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CN108361139A - The small fuel-flow control method of fuel injector - Google Patents

The small fuel-flow control method of fuel injector Download PDF

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Publication number
CN108361139A
CN108361139A CN201810082016.XA CN201810082016A CN108361139A CN 108361139 A CN108361139 A CN 108361139A CN 201810082016 A CN201810082016 A CN 201810082016A CN 108361139 A CN108361139 A CN 108361139A
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China
Prior art keywords
oil mass
injector
rail pressure
oil
fuel
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Granted
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CN201810082016.XA
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Chinese (zh)
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CN108361139B (en
Inventor
施华传
居钰生
顾欣
吴逸庭
马涛
邱云
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FAW Group Corp
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FAW Group Corp
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M65/00—Testing fuel-injection apparatus, e.g. testing injection timing ; Cleaning of fuel-injection apparatus
    • F02M65/001—Measuring fuel delivery of a fuel injector
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/24—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means
    • F02D41/2406—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means using essentially read only memories
    • F02D41/2425—Particular ways of programming the data
    • F02D41/2429—Methods of calibrating or learning
    • F02D41/2441—Methods of calibrating or learning characterised by the learning conditions
    • F02D41/2445—Methods of calibrating or learning characterised by the learning conditions characterised by a plurality of learning conditions or ranges
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/24—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means
    • F02D41/2406—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means using essentially read only memories
    • F02D41/2425—Particular ways of programming the data
    • F02D41/2429—Methods of calibrating or learning
    • F02D41/2477—Methods of calibrating or learning characterised by the method used for learning
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/30—Controlling fuel injection
    • F02D41/38—Controlling fuel injection of the high pressure type
    • F02D41/40—Controlling fuel injection of the high pressure type with means for controlling injection timing or duration
    • F02D41/402—Multiple injections
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/02—Input parameters for engine control the parameters being related to the engine
    • F02D2200/06—Fuel or fuel supply system parameters
    • F02D2200/0614—Actual fuel mass or fuel injection amount

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Combined Controls Of Internal Combustion Engines (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)

Abstract

The present invention relates to a kind of small fuel-flow control methods of fuel injector, it is characterized in that：The control method is to be dropped using the rail pressure before and after injector to be measured repeatedly small oil mass injection to carry out oil mass estimation, and estimation oil mass is compared with the basic oil mass characteristic curve of injector, its deviation factor relative to basic oil mass is obtained, is then filled in oil mass deviation factor learning table；After the study for completing oil mass deviation factor learning table, the oil mass pulse width conversion table Q2T of each injector alone is sought in the small corresponding deviation factor of oil mass nonlinear area applying working conditioni, and use revised Q2TiAcquisition of tabling look-up eventually passes through modified injection pulse width.The present invention can significantly improve the small oil mass consistency and control accuracy of injector, it solves the problems, such as that small oil mass between injector sprays high deviation and problem is corrected in aging, meets precision and oil mass coherence request that more maximum discharge and fuel economy regulation spray the small oil mass of injector.

Description

The small fuel-flow control method of fuel injector
Technical field
It is especially a kind of for being sprayed in fuel of internal combustion engine the present invention relates to a kind of small fuel-flow control method of fuel injector The control method of the middle injector oil mass compensation used, is suitable for the control of identity of injection when the small oil mass of any engine is sprayed Method belongs to engine injectors control technology field.
Background technology
The discharge and fuel economy regulation that China is increasingly stringenter just are becoming the driving force that market engine is changed.In view of lower Discharge and oil consumption, engine needs more first and then complicated control strategy to be adapted therewith, and these are small to fuel injector Higher requirements are also raised for the control accuracy and consistency of oil mass injection.Therefore, it is necessary to a new fuel injector oil spouts Control technology improves the control accuracy and consistency of fuel injector small oil mass injection.
In the prior art, the patent application CN201110355679 and CN201310224482 of horse Rayleigh company disclose one The inconsistent solution of the small oil mass of kind, implementation process are that multi-injection excitation injector is used to carry out small pulsewidth spray first It penetrates, the front and back rail pressure drop of small pulsewidth injection is then measured, to estimate the small oil mass of actual ejection, and the method for passing through statistical average To ensure the correctness of estimation oil mass；Estimation oil mass is finally compiled into oil mass compensation forms, to realize that oil mass compensates, enhancing spray Penetrate consistency.
The patent application CN103328796 of Bosch is intake and exhaust stroke (when injector leaves unused), not open injection The pulsewidth injection triggering injector of device needle-valve, at this time without oil spout, rail pressure drop is caused by oil return completely, can be by measuring rail pressure drop To determine recirculating oil quantity；And in normal injection, caused by rail pressure drop is the total amount being made of oil spout and oil return, it can be dropped by rail pressure Calculate distributive value (total amount-recirculating oil quantity).Finally, injector calibration is carried out using distributive value and recirculating oil quantity, to adjust each injection Oil spout scattered error between device, and realize injector compensation of ageing.
The method that Chinese patent application CN201110355679 is used to determine the jet law of fuel injector, discloses one How kind obtains the jet law of each injector and related fuel-flow control method, the jet law of fuel injector online to draw It is divided into four regions：Initial does not open region A, and since driving time is too short, injector, which is substantially at stationary state, to be sprayed Oil；Snap action region (batlistic zone) B, emitted dose Q is basic in approximation as driving pulsewidth becomes larger and quickly increases Linearity curve；And linear region D, injector are opened completely, emitted dose Q is as driving pulsewidth becomes larger and increases in a linear fashion. Joint region C connection snap actions region B to linear region D is greatly non-linear, to not recommend in join domain C Use fuel injector.The patent application disclose a kind of methods determining each injector jet law, can be approximately straight line R1 and straight line R2, straight line R1 are fitted snap action region B, and straight line R2 linears region D and intersect with straight line R1.Straight line R1 It is determined by characteristic point P1 and P2, straight line R2 is determined by characteristic point P3 and P4.Characteristic point P1-P4 as a whole can be close Like the jet law of accurately reconstruct injector.Since rail pressure has an impact jet law, each feature of jet law Point P1-P4 needs to determine at different fuel pressure P.Each respective jet law of injector is stored in the memory of ECU It is interior；ECU in use controls each injector using the jet law of each injector previously stored.
The method for determining each injector jet law is：
A, it interrupts and is supplied from oil pump to the fuel of rail pipe completely, avoided other than injector to be tested all other Injector is opened, and measures the initial fuel pressure in rail pipe by pressure sensor before opening injector to be tested Pi, then ECU with identical injection pulse width L drive injector, continuously spray n times, then measured after terminating injector oil spout Then final fuel pressure Pf in rail pipe obtains the pressure drop Δ P in the front and back rail pipe of oil pump capacity injection, is equal to the difference of Pi and Pf Value；
B, according to the total oil mass Q flowed out from rail pipeTOTRelated coefficient K between the pressure drop Δ P in rail pipe obtains QTOT= Δ P*K, and the fuel quantity Q of loss is subtracted, it both would know that single distributive value Q=(QTOT-QDamage)/N；ECU is by statistically handling pressure The series of measured values of Δ P is dropped to determine average pressure drop Δ P, can improve the accurate of Δ P and single injection event oil mass Q in this way Property, the characteristic point P1-P4 of the actual ejection rule of injector is determined by the above process, and then entire injection rule can be reconstructed Rule；
C, the implementation that n times are continuously sprayed includes two kinds：The first is that internal combustion engine is connected in external drive equipment, this Kind external drive equipment can keep internal combustion perseverance rotating speed to run, and how much be sprayed onto the actual oil mass in cylinder without pipe.Thus can Injector to be measured is allowed to implement the injection of the n times (N is more than 50) of continuous big figure, such pressure drop Δ P is relatively high, therefore is measured With regard to more accurate.Second is that can be tested in engine normal operation, changes internal combustion in certain error interval The demand fuel quantity Qd of machine, so that the oil mass Q sprayed in test action time T is exactly the integer factors of Qd, and And demand fuel quantity Qd preferably high as possible can improve pressure drop in this way so that injector to be measured can carry out several continuous unlatchings Measuring accuracy.Therefore total oil mass of the injection of n times continuous in this way is just consistent with demand oil mass Qd, can not thus influence interior Combustion engine normal operation.
Chinese patent application CN201310224482 is used to update method (the horse Rayleigh public affairs of fuel injector jet law Department), disclose it is a kind of how to be updated in engine normal operation and do not influence driver's normal driving vehicle in the case of it is each The method of the jet law of injector.Basic principle and thinking are similar with above-mentioned Chinese patent CN201110355679, only exist After ECU drives injector continuously to spray n times with identical injection pulse width L (total oil mass of n times injection is Q1), then also execute Second injection makes to start to compensate the requirement that total injection oil mass obtains needing oil mass Qd to keep the total oil mass of each cylinder almost the same Function works normally and is unlikely to allow driving and feels abnormal.It is required that total oil mass Q2 (Q2=Qd-Q1) of the second injection is necessary It falls in the linear region of spray characteristic, can thus meet the requirement that total oil mass reaches demand oil mass Qd.
Chinese patent application CN103328796A is used to determine the method (Bosch) of the controlled quentity controlled variable of injector, discloses A kind of method of determining injector controlled quentity controlled variable.The method is intake and exhaust stroke (when injector leaves unused), not open injector needle The pulsewidth injection triggering injector of valve, at this time without oil spout, rail pressure drop is caused by oil return completely, can be by measuring rail pressure drop come really Determine recirculating oil quantity；And in normal injection, caused by rail pressure drop is the total amount being made of oil spout and oil return, it can be dropped and be calculated by rail pressure Then total oil mass calculates distributive value (total amount-recirculating oil quantity).Finally, injector calibration is carried out using distributive value and recirculating oil quantity, to adjust Oil spout scattered error between whole each injector, and realize injector compensation of ageing.Specifically, by pre-defined fuel injection pulsewidth with Rail pressure triggers each cylinder injector injection, and the learning value of the distributive value and recirculating oil quantity according to rail pressure drop calculating injector to be measured, and It is stored in oil mass characteristic study table.After completing to learn, these learning values can be employed and carry out oil mass compensation.
The shortcoming of the patent application CN201110355679 and CN201310224482 of horse Rayleigh company are as follows：
(1) horse Rayleigh company chooses the determination that four characteristic point P1-P4 carry out rail pressure drop estimation oil mass under each rail pressure, Wherein, characteristic point P1 and P2 is in small oil mass nonlinear area, and P3 and P4 is in oil mass linear region, straight using 4 points two Line can the approximate jet law for accurately reconstructing injector.But the computational methods that use of horse Rayleigh be estimation oil mass absolute value with Fuel injection characteristic is reconstructed, but oil mass absolute magnitude can not characterize injector relative to the original basic characteristic aging journey of oil mass Degree.
(2) during implementing the multi-injection of oil mass self study, with the increase of injecting times, rail pressure when injection by It gradually reduces, although the pulsewidth of multi-injection is identical, the distributive value under different rail pressures is different, and horse Rayleigh is The total injection oil mass divided by injecting times of estimation are simply obtained into average single distributive value, as required starting rail pressure and required Practical single distributive value under pulsewidth does not consider the continuous influence declined to distributive value of pressure in course of injection；Horse Rayleigh This algorithm must be that and injecting times small on injection pulse width are less to premised on rail pressure drop very little.But if rail pressure , inherently can be not accurate enough to the measurement of rail pressure drop if decline is smaller, because the size order of magnitude of pressure drop is passed similar to pressure The minimum resolution when error size and reading pressure sensor of sensor.So this is an awkward selection, algorithm is necessary It is improved to avoid the irreconcilable contradiction of such inherence.Horse Rayleigh company attempts to unite to the rail pressure drop captured The method of meter come ensure rail pressure drop accuracy, although after the statistics of hundreds of number magnitudes, measure rail pressure drop accuracy It theoretically increases, but actually differs and surely meet the requirements.This method has also been aggravated significantly at the data of ECU simultaneously Reason burden, reduces the operational efficiency of algorithm, algorithm also necessarily expends the longer time.
(3) horse Rayleigh thinks that system will produce fuel loss when rail pressure is higher, can estimate it, and is sprayed in estimation The influence of fuel loss is deducted when oil mass.The first fuel loss is determined first, loses direct ratio in the duration of measurement, Then the second fuel loss is determined, this loses direct ratio in the unlatching number of fuel injector, finally by by the two values Addition obtains fuel quantity loss.Obvious horse Rayleigh is fairly simpleization, fuel oil damage about the processing method that fuel loss is estimated Mistake is different under different operating modes, such as has relationship with rail pressure and driving pulsewidth etc., while being contemplated that injector is old Change the influence to fuel loss.
(4) during oil mass self study multi-injection is implemented, in order to enable injector distributive value to be measured and demand oil mass Qd Unanimously, to can guarantee the internal combustion engine energy normal operation during oil mass self study, horse Rayleigh is after executing measurement injection, if surveyed The total oil mass sprayed during examination is Q1, and ECU will also execute the second injection, and distributive value is that (Q2=Qd-Q1, wherein Qd are injection to Q2 Device demand distributive value) so that the total fuel injection quantity of injector to be measured is identical as other fuel injectors.But when unlatching oil mass self study Afterwards, since injector to be measured carries out small oil mass multi-injection, the injection of self study stage small oil mass is certainly inaccurate, in turn results in Total oil mass is different from other a few cylinder distributive values, add combustion efficiency under multi-injection pattern may also can be impacted, finally Engine operation can be caused not steady enough or have subtle jitter phenomenon.
And Bosch has only carried out direction in patent application CN103328796 to oil mass compensation principle and compensatory device Property description explanation, do not refer to the specific steps for being dropped according to rail pressure and determining distributive value method specifically.
Invention content
The purpose of the present invention is overcoming the deficiencies in the prior art, a kind of small fuel-flow control side of fuel injector is provided Method is remarkably improved the small oil mass consistency and control accuracy of injector, solves the high deviation of the injection of the small oil mass between injector and asks Problem is corrected in topic and aging, meets precision and oil mass consistency that more maximum discharge and fuel economy regulation spray the small oil mass of injector It is required that.
According to technical solution provided by the invention, the small fuel-flow control method of fuel injector, it is characterized in that：The control Method processed is that repeatedly small oil mass is sprayed front and back rail pressure and dropped and carries out oil mass estimation using injector to be measured, and estimation oil mass with The basic oil mass characteristic curve of injector is compared, and is obtained its deviation factor relative to basic oil mass, is then filled with oil mass In deviation factor learning table；After the study for completing oil mass deviation factor learning table, in small oil mass nonlinear area applying working condition Corresponding deviation factor seeks the oil mass pulse width conversion table Q2T of each injector alonei, and use revised Q2TiIt tables look-up and obtains It takes and eventually passes through modified injection pulse width；Specifically include following steps：
(1) oil mass self study, which is opened, judges：Judge whether fuel injector needs to open oil mass self-learning function；
(2) oil mass estimation is enabled judges：After opening oil mass self-learning function, external condition judgement is carried out：Assess vehicle Whether the external status or working condition requirement of oil mass estimation are met；And carry out interior condition judgement：To fuel system leakproofness into Row detection is to judge whether fuel system meets oil mass estimation inner sealing requirement；After inner and exterior conditions all meet, enable Oil mass estimation function；
(3) rail pressure acquires before oil spout：After enabled oil mass estimation function, pump oil function and oil spout function are closed, in fuel oil In the case that system is without fuel oil input and output and rail pressure stabilization, rail pressure acquisition and acquisition before injector injection to be measured starts are carried out Rail pressure reasonability judges；
(4) injector sprays：Before completing to spray after rail pressure acquisition, the ejection function of injector is executed, it is suitable to select Injecting times and injection pulse width use multi-injection mould in the case where closing pump oil and other cylinder not oil spouts in addition to cylinder to be measured Formula triggers injector to be measured and executes N+1 injection, includes the continuous injection of the identical short pulse duration of n times, and separately add 1 micro- closed loop compensation Injection；
(5) rail pressure acquires after oil spout：After injector completes the continuous injection of the identical short pulse duration of n times, carry out again to be measured Rail pressure acquisition after injector injection judges with rail pressure acquisition reasonability；
(6) rail pressure drop calculates：According to the front and back pressure difference of injection, the injection rail pressure drop of injector to be measured is calculated, to rail pressure Drop carries out reasonability judgement, to obtain final rail pressure drop output mean value；
(7) total oil mass is estimated：According to the rail pressure drop mean value and related coefficient being calculated, seek estimating under current working Rail pipe flow out total oil mass QAlways；
(8) recirculating oil quantity is calculated：Experiment determines that different rail pressures are corresponding with driving pulsewidth and returns substantially before injector manufacture Oil mass, and insert basic recirculating oil quantity table；The oil return aging factor λ under different rail pressures is calculated, and using aging factor to basic Oil return scale is modified, to obtain the recirculating oil quantity after aging；
(9) single injection event oil mass is estimated：Total oil mass Q is flowed out according to the rail pipe estimated under current workingAlwaysWith recirculating oil quantity QIt is total to returnMeter Calculate the single injection event estimation oil mass Q of current injector to be measuredEstimation, QEstimation=α * (QAlways–QIt is total to return)/N, wherein α are rail pressure dynamic decline pair The correction factor of single injection event oil mass, N are injecting times；
(10) oil mass deviation factor learning table updates：It is oily to obtain the single estimation injection that different rail pressure differences correspond under pulsewidth Measure QEstimation, and deviation factor γ of the estimated single injection event oil mass relative to basic oil mass is calculated, and update the oil of each injector Measure deviation factor learning table；
(11) fuel injector degradation failure：According to the oil mass deviation factor γ after fuel injector agingAgingPass through when relative to manufacture The deviation factor γ that oil mass self study obtainsManufactureDrift value Δ γ judge fuel injector degree of aging, and with preset failure threshold value It is compared, to determine whether fuel injector occurs degradation failure；
(12) fuel injection pulsewidth is coordinated：After completing self study, after each injector amendment is obtained according to oil mass deviation factor Oil mass pulse width conversion table, and look into revised oil mass pulse width conversion table and obtain the revised injection pulse width of final process.
Further, the condition that the oil mass self study is opened never had carried out oil mass since including this group of injector manufacture Self study had carried out oil mass self study but had needed to carry out aging amendment to injector；The modified oil mass self study of aging Unlocking condition includes that the last aging amendment engine of distance has run certain time or corrected vehicle apart from last aging again Again travelled certain mileage or under characteristic operating point open this detected deviation factor phase of oil mass estimation function The offset of deviation factor when being corrected for last aging is more than the modified threshold value of aging.
Further, after oil mass self study unlatching, external condition and interior condition are judged；The outside Rule of judgment includes that vehicle operates in unfaulty conditions, rail pressure sensor acquisition fault-free, power source supplying voltage stabilization, rail pressure wave Dynamic range is less than threshold value and stablizes more than a period of time；The interior condition judgment method is：Vehicle, which is in, forbids spray pump oil to make Fuel system without oil inlet with it is fuel-displaced in the state of, record under different rail pressures, rail pressure in unit interval drop, and complete rail pressure drop and let out The update for leaking table drops the rail pressure under current rail pressure compared with the current rail pressure lower rail pressure drop leak threshold of predefined, rail pressure When drop is less than threshold value, it is believed that fuel system leakproofness meets internal judgment condition.
Further, before oil mass estimation, it is modified using fuel system leakage rail pressure drop, specific side Method is dropped according to unit interval fuel leakage rail pressure to calculate under current rail pressure, under the injector fuel injection pulsewidth duration to be measured Fuel leakage pressure drop Δ PLeakage, use leakage rail pressure drop Δ PLeakageInjector distributive value to be measured estimation and recirculating oil quantity estimation are used Rail pressure drop be modified, influenced with removing caused by fuel leakage rail pressure drop, enhance estimation precision.
Further, after enabled oil mass estimation function, signal is characterized by detecting each cylinder torque difference, and then will be to be measured Cylinder torque is compared with non-cylinder average torque to be measured, is adjusted with implementing micro- closed-loop control to cylinder oil mass to be measured, to be waited for The micro- closed loop adjusting oil mass △ Q for surveying cylinder, reach the coherence request of each cylinder torque.
Further, after injector aging causes recirculating oil quantity to deviate, using oil return aging factor, to basic oil return scale It compensates and corrects；Calculating acquisition aging factor condition is：Vehicle is in the state for not needing injector work, in this case The oil mass estimation function of injector to be measured is triggered with Standard pulse-width, this Standard pulse-width can not open the actuating injection of injector needle-valve Device, but will produce the oil return of injector, then oil return aging factor λ is the base for estimating recirculating oil quantity and acquisition of tabling look-up according to Standard pulse-width The ratio of this recirculating oil quantity, i.e. λ=QEstimate oil return/QBasic oil return, the aging factor under different rail pressures is obtained, and use aging factor under each rail pressure Basic oil return scale is modified, to obtain the recirculating oil quantity after aging.
Further, the rail pressure dynamic declines is to the finding process of the correction factor α of single injection event oil mass：It is spraying Rail pressure continuously decreases in the process, and it is mean rail pressure P during declining relative to rail pressure dynamic to lead to actual ejection oil massmBe averaged Spray oil mass Qm, using correction factor α to QmIt is modified, to obtain initial injection rail pressure PInitiallyUnder single injection event oil mass QEstimation； When driving pulsewidth to fix, Q2T tables are looked into according to rail pressure and can get distributive value, i.e. Q=Map (P), then correction factor α=Map (PInitially)/Map(Pm)；The method of α is sought to improve precision using successive ignition.
Further, the single injection event estimation oil mass Q under different rail pressures and the corresponding driving pulsewidth of basic oil mass is obtainedEstimation Afterwards, deviation factor γ, wherein γ=(Q of the estimation oil mass relative to basic oil mass are calculatedEstimation-QSubstantially)/QSubstantially, and according to substantially oily Amount is inserted deviation factor in the oil mass deviation factor learning table of test injector with rail pressure.
Further, when unfinished oil mass self study, the injection when acquisition of Q2T tables does not learn is looked into according to rail pressure and oil mass Pulsewidth；Complete learn after, can be used the respective oil mass pulse width conversion table of injector table look-up obtain study after injection pulse width；Respectively The Q2T of injectoriThe determination method of table is：First, according to oil mass deviation factor learning table, some rail in basic Q2T tables is determined Depress the estimation oil mass corresponding to each oil mass coordinate value, i.e. QEstimation=(1+ γ) * QSubstantially；It thus obtains anti-under current rail pressure It reflects estimation oil mass and drives the interim estimation oil mass inquiry table of relationship between pulsewidth；Further according to estimation oil mass inquiry table, using slotting The method of value calculates current injector Q2TiPractical driving pulsewidth in table under current rail pressure corresponding to each oil mass coordinate value； Above method is repeated under different rail pressures, you can complete the corresponding Q2T of fuel injector to be measurediThe update of table.
The small fuel-flow control method of fuel injector of the present invention can make injector reach high-precision when spraying fuel Control effect and keep identity of injection, the multi-injection requirement under higher emission regulation can be met, reach engine energy-saving The purpose of emission reduction.
Description of the drawings
Fig. 1 is the structure diagram of fuel injection system.
Fig. 2 is pulsewidth-distributive value curve of each injector in fuel injection system.
Fig. 3 is that fuel system leaks rail pressure monitoring curve.
Fig. 4 is the correlativity curve that fuel system injector oil mass and rail pressure drop.
Fig. 5 is oil mass under certain pulsewidth with rail pressure change curve.
Fig. 6 is to drop estimation distributive value and the modified algorithm schematic diagram of pulsewidth based on rail pressure.
Fig. 7 is the oil mass characteristic curve aging schematic diagram of injector.
Fig. 8 is to update injector oil mass pulse width conversion table Q2T to be measurediSchematic diagram.
Specific implementation mode
The present invention is directed to the high deviation of the small oil mass injection characteristics of existing electric-control motor fuel nozzle, the problem of consistency difference, It is dropped by the rail pressure before and after calculating injector to be measured repeatedly small oil mass injection to carry out oil mass estimation, and estimation oil mass and sprayed The basic oil mass characteristic curve of device is compared, and is obtained its deviation factor relative to basic oil mass, is then filled with oil mass deviation In coefficient learning table；After the study for completing oil mass deviation factor learning table, corresponding operating mode is used in small oil mass nonlinear area Deviation factor seek the oil mass pulse width conversion table Q2T of each injector alonei, and use revised oil mass pulse width conversion table Q2TiAcquisition of tabling look-up eventually passes through modified injection pulse width, to improve the oil mass consistency of oil spout nonlinear area.
For theoretically, fuel system leakage is the abnormality of system, should generally avoid the generation of leakage as possible, but real Fuel system unavoidably will produce leakage on border, it is considered herein that before carrying out rail pressure drop estimation oil mass, it should be ensured that Fuel System The leakage rate of system is met the requirements；Specifically, under the operating mode (such as vehicle towing astern) that injector does not spray, forbid spray pump oily, at this time In fuel system without oil inlet with it is fuel-displaced, the rail pressure detected using ECU is declined at any time is mainly caused by fuel system leaks, It records under different rail pressures, the rail pressure drop in the unit interval, and inserts in rail pressure drop leakage table.Before oil mass estimation, basis is needed Current rail pressure obtains the rail pressure drop in rail pressure drop leakage table, and drops fault threshold ratio with the rail pressure under the current rail pressure of predefined When being less than threshold value compared with, only in-orbit pressure drop, just think that fuel system leakproofness is met the requirements.
Even if the leakage of unit interval fuel system is less than threshold value, in order to ensure the accuracy of oil mass estimation, estimated in oil mass When rail pressure drop Δ P ' is calculated after, still fuel system leakage can be used to be modified it, specific method is, according to Unit interval fuel leakage rail pressure drops to calculate the fuel leakage pressure drop Δ P under the injector fuel injection pulsewidth duration to be measuredLeakage, then Eliminate rail pressure drop Δ P=Δs P '-Δ P of fuel leakage influenceLeakage.It should be noted that the rail pressure drop such as Δ referred in text P、ΔPOil returnEtc. be deducted fuel system leakage rail pressure drop.
In order to improve the front and back rail pressure acquisition precision of injector injection to be measured, the present invention has carried out multiple rail afterwards before ejecting Pressure acquisition, and the extent of deviation of these rail pressure collection values is judged, reject the rail pressure collection point that deviation is more than threshold value.Only After collecting multiple deviation degree smaller rail pressure collection value, the front and back rail pressure final output mean value of acquisition can be just confirmed.Make After being acquired with space of teeth rail pressure, entire gatherer process can be made to be completed in injector working cycles to be measured.
The present invention controls injection to enhance the reduction degree of rail pressure using the method for multi-injection, is distinguished with improving rail pressure drop Know precision.After completing injection and the front and back rail pressure acquisition of injection, acquisition injection rail pressure drop can be calculated.In order to reinforce rail pressure drop meter The accuracy of calculation, the present invention equally judges the rail pressure drop extent of deviation being repeatedly calculated, and is more than to reject deviation The rail pressure of threshold value drops.When collect enough extent of deviation it is smaller rail pressure drop after, can calculate rail pressure drop final output it is equal Value.
In order to make the oil mass of multi-injection be independent of each other, invention provides for the minimum injection interval angles of multi-injection, make Confirm minimum injection interval angle that oil mass is independent of each other with theoretical calculation or the method for experiment.The present invention sprays minimum It is spaced as one of the restrictive condition for opening rail pressure drop confirmation oil mass function, only demand injection pulse width long enough, meets multiple Oil mass estimation function could be opened when the pulsewidth of small oil mass injection is with minimum interval angle requirement.
The study found that from rail pipe flow out oil mass Q and rail pipe in pressure drop Δ P between have strong correlation.Specifically, oily The relative coefficient K of the amount Q and pressure drop Δ P in rail pipe is mainly determined by the compression modulus of the internal capacity of rail pipe and fuel jointly It is fixed.The internal capacity of rail pipe is fixed, and the compression modulus of fuel is by fuel type, bearing capacity (rail pressure) suffered by fuel and The decisions such as fuel oil temperature.Therefore related coefficient is the function of rail pressure and oil temperature, i.e. K=Fun (P, T).The present invention constructs correlation Coefficient lookup table is determined using the method for theoretical calculation Binding experiment under different rail pressures, oil temperature, the value feelings of related coefficient Condition.It after related coefficient is determined, can be dropped according to the rail pressure obtained is calculated, using formula Q=Δ P*K, seek the outflow of rail pipe Oil mass Q.
It studies and also found, the total oil mass Q generally flowed out from rail pipeAlways(having deducted fuel system leakage) can be by following two Oil mass is divided to constitute：(1) oil return, when injector works, fuel injection pulsewidth is shorter, is not enough to open injector needle-valve, though at this time Right injector can lead to the generation of injector interior oil return without distributive value；(2) oil mass is sprayed, when injector can open injection When the pulsewidth work of device needle-valve, oil return, but also triggering injector oil spout not only occurs.Therefore, it is necessary to use a kind of method, it is first determined The oil return Q of fuel system under current workingIt is total to return, then determine total oil mass Q of rail pipe outflow after the injector injection under current workingAlways, The injection oil mass Q of last injectorTotal spray=QAlways–QIt is total to return。
The corresponding recirculating oil quantity of certain injection pulse width under the manufacture certain rail pressure of injector can be determined using the mode of experiment, and This recirculating oil quantity is inserted in recirculating oil quantity inquiry table；Therefore, in the ideal case, the acquisition that can be tabled look-up according to rail pressure and injection pulse width is single The recirculating oil quantity of secondary injection, i.e. QOil return=Map (P, T).
In real engine operational process, each injector can gradual aging, this causes the recirculating oil quantity of each injector to generate Creep, tabling look-up the recirculating oil quantity sought at this time will be no longer accurate.The present invention proposes a kind of method, after determining injector aging Recirculating oil quantity.Specific method is under vehicle towing astern operating mode or scavenging stroke (injector does not have to work at this time), to stop injector Oil spout and oil pump pump oil, make fuel system be not only pumped into without fuel oil, but also are sprayed without fuel oil, trigger injection to be measured later with Standard pulse-width Device multi-injection can not open injector needle-valve actuating injector under this pulsewidth, but the oil return of injector can occur, acquire and count Calculate the oil return rail pressure drop under Standard pulse-width, and the oil return estimator Q being scaled under Standard pulse-widthEstimate oil return.When aging occurs for injector When, QEstimate oil returnTable look-up the basic recirculating oil quantity Q of acquisition with Standard pulse-widthBasic oil returnDifference will be generated, definition oil return aging factor is λ, In
After recirculating oil quantity aging factor is determined, the present invention devises the method for determining injector oil mass to be measured.Starting When machine normal operation, injector injection to be measured is triggered using the method for multi-injection, since injection pulse width is beaten more than injector Open minimum pulse width so that injector needle-valve is opened, and rail pressure drop at this time is collectively formed by distributive value and recirculating oil quantity, acquires and remember It records rail pipe and flows out rail pressure drop caused by total oil mass, and be scaled total estimation oil mass QAlways；Simultaneously according to pulsewidth and rail pressure computation of table lookup Basic recirculating oil quantity, and according to the oil return aging factor oil return Q total to fuel systemIt is total to returnIt is modified；Then the injection of injector is always estimated Calculate oil mass QTotal spray=QAlways–QAlwaysIt returns.
During multi-injection, with each fuel injection, rail pressure when injection continuously decreases, and therefore, sprays each time The starting rail pressure penetrated is different, and which results in the differences of distributive value.If not considering the influence that rail pressure dynamic declines, obtaining It obtains injector and always sprays estimation oil mass QTotal sprayAfterwards, can single distributive value Q directly be calculated according to injecting times NEstimation, QEstimation=QTotal spray/ N, and the present invention then thinks, although driving pulsewidth is identical, due to initial injection rail pressure PInitiallyDifference, can not be simply by QAlways/ N is as initial injection rail pressure PInitiallyUnder single injection event oil mass.This is to say, QAlwaysDivided by what N obtained is rail pressure dynamic decline process In average injection oil mass Qm, need to use average distributive value pair with the variation relation of rail pressure according to oil mass under current driving pulsewidth The rail pressure P answeredmTo QmIt is modified, the practical single injection event oil mass Q under initial injection rail pressure could be obtainedEstimation.Specifically, due to Oil mass can be embodied with the variation relation of rail pressure in Q2T tables, therefore after driving pulsewidth to fix, looking into Q2T tables can must spray Oil mass, i.e. Q=Map (P), then correction factor α=Map (PInitially)/Map(Pm), then the single distributive value under initial injection rail pressure QEstimation=α * Qm=α * QTotal spray/ N=α * (QAlways–QIt is total to return)/N.Since the primary standard injector used in first time oil mass self study is special Property data Q2T tables accuracy it is insufficient, therefore calculate the correction factor α obtained for the first time there is certain deviation, but with the The completion of oil mass self study, second of self study will be corrected using newer each individual Q2T tables of injector to calculate Factor alpha, after the iterating of self study several times, the accuracy of correction factor α will be promoted gradually, the essence of small oil mass estimation Degree also will be promoted further.
The present invention devises the oil mass deviation factor learning table of each injector, the list in the case where obtaining different rail pressures and pulsewidth Secondary injection estimation oil mass QEstimationAfterwards, deviation factor γ of the estimation oil mass relative to basic oil mass is calculated, whereinAnd Deviation factor is inserted in the oil mass deviation factor learning table of test injector.It can be defined according to the oil spout precision of project demand Study operating point number (generally being deleted on the basis of basic oil mass Q2T tables) in oil mass deviation factor learning table, To be balanced in terms of learning efficiency and study accuracy.
The deviation factor of injector represents extent of deviation of the injector relative to basic fuel injection characteristic, when fuel injector dispatches from the factory When, the purpose of estimating injector deviation factor γ manufactures is the deviation journey in order to determine fuel injector oil mass compared to basic oil mass Degree, to carry out small oil mass compensation control；When aging occurs in injector, injection characteristics curve will totally shift, and open at this time The purpose that oil mass estimation study calculates oil mass deviation factor γ agings is opened, is to determine shadow that aging generates oil spout curve It rings, then drift value Δ γ=γ of oil mass deviation factorAging–γManufacture, the degree of aging of injector can be characterized with this drift value. Invention defines bias drift degradation failure threshold values, when Δ γ has been more than aging threshold, remind the old of driver's fuel injector Change is very serious, carries out troubleshooting at this time and simultaneously closes oil mass estimation self study.Meanwhile it can also be to oil using deviation factor The accuracy of amount estimation is judged, if after carrying out oil mass estimation study, finds the deviation system that acquisition is calculated under certain operating mode Number is much larger than last same condition calculating much larger than the deviation factor of other operating points or this deviation factor for calculating acquisition When the deviation factor of acquisition, oil mass estimation accuracy will be under suspicion, ECU by again confrontation doubtful point deviation factor again into Row calculates.
In order to determine aging modified opportunity, in addition to the mileage number for using the last aging amendment of distance to pass through or start Machine run time can also detect engine and be in characteristic operating point and run come outside being judged in the characteristic operating point of setting When deviation factor γFeature (i), and calculate deviation factor γ when it is corrected relative to last agingFeature (i-1)Offset Δ γ ', by judge Δ γ ' whether more than aging correction threshold come determine fuel injector whether need carry out aging amendment.
Can engine during normal operation, complete injector to be measured oil mass estimation and self study.It is transported in internal combustion engine During row, when spray regime is in linear big pulsewidth region, the primary long pulsewidth injection of injector to be measured can be divided into has Limit time N short pulse durations continuously with single compensation spray by injection, and the injection of injector N+1 times is completed using the mode of multi-injection Function.Wherein n times injection is to carry out oil mass estimation, and total oil mass of injection is Q1；And remaining 1 injection is compensation spray It penetrates, effect is to ensure that the torque before and after opening oil mass estimation is consistent, then compensates distributive value Q2=Qd-Q1, and wherein Qd is injection Device demand distributive value.
Since injector to be measured carries out small oil mass n times injection, and the injection of self study stage small oil mass is accurate not enough, though Right target is Q1, but there are deviations by actual oil mass affirmative and Q1, in turn result in the total oil mass and other several cylinders of injector to be measured The total oil mass of injector is different, along with the combustion efficiency under multi-injection pattern may also can be impacted, eventually lead to cylinder to be measured Torque and other several cylinders caused by (cylinder belonging to injector i.e. to be measured, same as below) are different, to show as starting The machine fluctuation of speed, vehicle occur running not steady enough or have subtle jitter phenomenon.
To solve the above-mentioned problems, the present invention is used and is carried out to cylinder torque to be measured after opening oil mass self-learning function The method of closed-loop control compensation.Due to the difference of torque produced by each cylinder, it can be embodied on each cylinder transient rotative speed and (need to note Meaning, the torque difference token state of use includes but not limited to transient rotative speed, such as also transient rotative speed increment, cylinder pressure etc. Each cylinder torque difference can be characterized, in embodiment by taking each cylinder transient rotative speed as an example), therefore ECU is by detecting each cylinder transient rotative speed, And then cylinder transient rotative speed to be measured is compared with the average transient rotative speed of non-cylinder to be measured, so that it may with the oil mass Δ Q to cylinder to be measured into The micro- closed loop of row is adjusted, so that cylinder torque to be measured is identical as other cylinders, or the torque difference of cylinder to be measured and other cylinders is controlled micro- In small range, this small torque difference is usually that allow and driver is inconspicuous.
Specific implementation steps are that after opening oil mass self study, ECU opens each cylinder transient rotative speed of engine or wink immediately The detection function of state incremental speed, and calculate cylinder rotating speed N to be measuredTransient stateRelative to non-cylinder transient rotative speed mean value N to be measuredIt is averageDifference, Its discrepancy delta NDifference=| NTransient state-NIt is average|.Speed difference threshold value can be determined by rating test, as Δ NDifferenceWhen less than threshold value, vehicle Even running；Conversely, working as Δ NDifferenceWhen more than threshold value, then it is assumed that vehicle operation is unstable, needs the torque for carrying out cylinder to be measured is micro- to close Ring controls, and ECU is according to Δ NDifferenceTo calculate adjusting oil mass Δ Q (specifically, can be with Δ NDifferencePass through PID control for feedback quantity Method calculates Δ Q, but be not restricted to that such method.), and then closed loop adjusts cylinder compensation distributive value Q2 (Q2=at this time to be measured Qd-Q1+ Δ Q) so that Δ NDifferenceLess than threshold value, then it represents that cylinder to be measured is consistent with other each cylinder torques, so that it is guaranteed that opening oil mass Vehicle energy even running when self study.
Oil mass estimation is completed with after oil mass deviation factor self study, the oil mass of basic Q2T tables and each injector can be used Deviation factor learning table obtains the oil mass pulse width conversion table Q2T of each injector alonei, to carry out small oil mass nonlinear area Oil mass compensates.In general, oil mass pulse width conversion table Q2TiReference axis be with operating point number and oil mass deviation factor learning table Consistent, the pulse-width data being initialized as in basic oil mass Q2T tables.After completing oil mass deviation factor learning table, first, Oil mass deviation factor learning table can be used to calculate the estimation in Q2T tables under some rail pressure corresponding to each oil mass coordinate operating point Oil mass, i.e. QEstimation=(1+ γ) * QSubstantially, wherein QSubstantiallyFor each oil mass coordinate value in basic Q2T fuel level gauges；Thus obtain Reflection estimates oil mass and drives the interim estimation oil mass inquiry table of relationship between pulsewidth under current rail pressure；Finally further according to estimation oil Amount inquiry table calculates Q2T using the method for interpolationiReality in table under current rail pressure corresponding to each oil mass coordinate operating point Drive pulsewidth.Above method is repeated under each rail pressure coordinate value, you can complete the corresponding Q2T of fuel injector to be measurediThe update of table.
The invention will be further described With reference to embodiment.
It is fuel injection system structure diagram as shown in Figure 1.Fig. 1 intermediate fuel oils are sucked into from the fuel tank 1 with coarse filter Secondary fuel oil filter 2, a portion fuel oil in the plunger cavity of oil pump 3 are pressed to form the fuel oil of pressure and from 3 delivery valves of oil pump Mouthful flowing through oil pipe merges into high-voltage tube 5, and steady and sustained pressurized fuel source is provided for the injection of injector 7, and redundance is from oil At overflow valve on pump 3 fuel tank 1 is flowed back to together with 7 oil return of injector；Pressurized fuel is flowed to from pressure pipe 5 through pressure oil pipe respectively The injector 7 of each cylinder；Injector 7 is according to the pulse given times exported of electronic control unit ECU 8 and given width, by feature Spray characteristic sprays into fuel oil in the combustion chamber of each cylinder of engine.5 one end of pressure pipe is equipped with rail pressure sensor 6, real time monitoring Rail pressure situation in pressure pipe 5, when rail pressure is more than the maximum value allowed, relief valve 4 is opened, and the rail pressure in pressure pipe 5 is rapid It is reduced in safe range, to ensure the safety of whole system.It is real that the electronic control unit 8 of pressure system acquires each sensor When the engine that detects and pressure system state parameter, accurate electric current arteries and veins is sent out by built-in control strategy and storage data Signal is rushed, and makes corresponding compression pump solenoid valve, injector solenoid valve etc. and generate electromagnetic force, to drive corresponding actuator to carry out Action, makes fuel delivery, rail pressure, oil spout angle and distributive value carry out feedback regulation on demand.It is passed used by pressure jet system Sensor 9 includes：Speed probe, pressure sensor, cooling-water temperature transmitter, fuel temperature sensor, crank angle sensing Device (or camshaft angle sensor), accelerator pedal sensor etc. are a variety of, are also equipped on some engines：Vehicle speed sensor, sky The other sensors such as mass-air-flow sensor, barometric pressure sensor, boost-pressure sensor, atmosphere temperature transducer.Electronics control The actuator driven signal 10 of unit 8 processed includes：Injector solenoid valve and high-pressure oil pump solenoid-driven signal.
In the present embodiment, electronic control unit ECU8 plays a part of fuel injection controller.EUC8 is generally acknowledged micro- Type computer, it grasps working condition and the operator demand of engine according to each sensor signal, and by pumping oil spout Drive signal carrys out response control demand.ECU8 generally comprises computing device (CPU), storage device (deposit by program storage Rom, data Store up EEPROM, backup RAM), signal processing apparatus (A/D converter and clock generation circuit), communication device (serial communication, CAN Communication device).
As shown in Fig. 2, for pulsewidth-distributive value curve of each injector in certain fuel injection system, it is in fig. 2, each to spray Emitted dose otherness between emitter is larger, this problem will be especially acute in ballistic area, because, between injector and injector The high deviation of injection characteristics is mainly related with the deviation in injector parts manufacturing process size in ballistic area；However by In come the deviation for reducing the injection characteristics in ballistic area being very multiple by reducing the deviation in parts manufacturing process size It is miscellaneous and therefore cost is high.Meanwhile even if deviation when dispatching from the factory between fuel injector is preferable, but the aging of fuel injector is existing As can also consistency be made to be deteriorated, injection difference problem will be complicated further, such aging can make injection characteristics with when Between passage generate creep.
As shown in figure 3, for fuel system leak rail pressure monitor curve, theoretically for, fuel system leakage be system Abnormality should generally avoid the generation of leakage as possible, but actually fuel system unavoidably will produce leakage, and the present invention recognizes For before the oil mass estimation dropped based on rail pressure, it should be ensured that the leakage rate of fuel system is met the requirements；Specifically, spraying Under the operating mode (such as vehicle towing astern) that device does not spray, forbid spray pump oily, at this time in fuel system without oil inlet with it is fuel-displaced, examined using ECU Caused by the rail pressure measured declines mainly fuel system leakage at any time, record under different rail pressures, the rail in the unit interval Pressure drop, and insert in rail pressure drop leakage table.Before oil mass estimation, need to obtain the rail in rail pressure drop leakage table according to current rail pressure Pressure drop, and compared with the current rail pressure lower rail pressure drop fault threshold of predefined, when only in-orbit pressure drop is less than threshold value, just think Fuel system leakproofness is met the requirements.Rail pressure drop shown in Fig. 3 is formed in 1min clocks, in practical applications can be according to tool Body working condition sets the rational unit interval, and estimates that threshold value drops in rail pressure caused by fuel leakage.
Even if the leakage of unit interval fuel system is less than threshold value, in order to ensure the accuracy of oil mass estimation, estimated in oil mass When rail pressure drop Δ P ' is calculated after, fuel system leakage rail pressure drop still can be used to be modified it, specific method It is to be dropped according to unit interval fuel leakage rail pressure to calculate under current rail pressure, the combustion under the injector fuel injection pulsewidth duration to be measured Oil leakage pressure drop Δ PLeakage, specific current rail pressure leakage rate Δ PLeakage=TInjection×ΔPUnit leaks÷TUnit, wherein TUnitIt is examined for unit Survey time, TInjectionFor injection pulse width.Then eliminate rail pressure drop Δ P=Δs P '-Δ P of fuel leakage influenceLeakage.It needs to illustrate It is rail pressure drop such as the Δ P, Δ P referred in the present embodimentOil returnEtc. be deducted fuel system leakage rail pressure drop.
In order to improve the front and back rail pressure acquisition precision of injector injection to be measured, multiple rail pressure is carried out afterwards before ejecting and has adopted Collection, and the extent of deviation of these rail pressure collection values is judged, reject the rail pressure collection point that deviation is more than threshold value.Only when adopting After collecting the smaller rail pressure collection value of multiple deviation degree, the front and back rail pressure final output mean value of acquisition can be just confirmed.It uses After the rail pressure acquisition of space of teeth, entire gatherer process can be made to be completed in injector working cycles to be measured.
It can enhance the reduction degree of rail pressure to control injector injection using the method for multi-injection, be distinguished with improving rail pressure drop Know precision.After completing injection and the front and back rail pressure acquisition of injection, acquisition injection rail pressure drop can be calculated.In order to reinforce rail pressure drop meter The accuracy of calculation, the present invention equally judges the rail pressure drop extent of deviation being repeatedly calculated, and is more than to reject deviation The rail pressure of threshold value drops.When collect enough extent of deviation it is smaller rail pressure drop after, calculate rail pressure drop final output mean value.
In order to make to be independent of each other between adjacent injection in multi-injection, it is specified that the minimum injection interval angle of multi-injection. Confirm minimum injection interval angle that oil mass is independent of each other using theoretical calculation or the method for experiment, and different injection works Minimum interval inquiry table is inserted in the minimum injection interval determined under condition.Confirm oil using minimum injection interval as rail pressure drop is opened One of the restrictive condition of function, only demand injection pulse width long enough are measured, between the pulsewidth and minimum that meet repeatedly small oil mass injection Oil mass estimation function could be opened when angle requirement.When carrying out multi-injection, being tabled look-up according to spray regime, acquisition is minimum to spray Oily interval angles, and provide that adjacent injection interval cannot be less than minimum injection interval angle.
As shown in figure 4, the correlativity curve dropped for each injector oil mass of fuel system and rail pressure.The study found that from rail There is strong correlation between pressure drop Δ P in the oil mass Q and rail pipe of pipe outflow.Specifically, the pressure drop Δ P in oil mass Q and rail pipe Relative coefficient K mainly by the compression modulus of the internal capacity of rail pipe and fuel codetermine.The internal capacity of rail pipe is solid It is fixed, and the compression modulus of fuel is by fuel type, the decisions such as bearing capacity (rail pressure) and fuel oil temperature suffered by fuel.Due to tool Fuel type in internal combustion engine is constant, therefore related coefficient is the function of rail pressure and oil temperature, i.e. K=Fun (P, T).This Invention constructs related coefficient inquiry table, is determined under different rail pressures, oil temperature using the method for theoretical calculation Binding experiment, related The value condition of coefficient.After related coefficient is determined, it can drop according to the rail pressure obtained is calculated, using formula Q=Δ P*K, ask The oil mass Q for taking rail pipe to flow out.
As shown in Figure 1, generally after the continuous injection of the identical short pulse duration of n times, from total oil mass Q of rail pipe outflowAlwaysIt (has deducted Fuel system leakage) it can be made of two parts oil mass：The oil return of injector 7 and the injection oil mass of injector 7.Therefore, it is necessary to Using a kind of method, the oil return Q that fuel system is total under current working is determinedIt is total to return, then determine current working under injector injection after Total oil mass Q of rail pipe outflowAlways, total injection oil mass Q of last injectorTotal spray=QAlways–QIt is total to return.It can be determined using the mode of experiment The corresponding recirculating oil quantity of certain injection pulse width under certain rail pressure, and this recirculating oil quantity is inserted in recirculating oil quantity inquiry table；Therefore, in fuel injector When aging not occurring, it can be tabled look-up according to rail pressure and injection pulse width and obtain the recirculating oil quantity of single injection event, i.e. QOil return=Map (P, L), institute With the total recirculating oil quantity Q of the identical short pulse duration of n times continuously sprayedIt is total to return=N*QOil return=N*Map (P, L).
In real engine operational process, each injector can gradual aging, this causes the recirculating oil quantity of each injector to generate Creep, tabling look-up the recirculating oil quantity sought at this time will be no longer accurate.It is λ that the present invention, which defines and calculates oil return aging factor, is sprayed with determining Recirculating oil quantity after emitter aging.The computational methods of aging factor are, including but not limited in vehicle towing astern operating mode or ventilation row Under journey (injector does not have to work at this time), stops injector oil spout and oil pump pump oil, so that fuel system was not only pumped into without fuel oil, but also nothing Fuel oil sprays, and triggers injector multi-injection to be measured later with Standard pulse-width, and the actuating of injector needle-valve can not be opened under this pulsewidth Injector, but the oil return of injector can occur, the rail pressure drop generated according to oil return calculates oil return estimator QEstimate oil return.Work as injector When aging occurs, QEstimate oil returnWith the basic recirculating oil quantity Q for acquisition of being tabled look-up by Standard pulse-widthBasic oil returnDifference will be generated, thenBasic recirculating oil quantity inquiry table is modified using aging factor, and is sought using revised oil return inquiry table Recirculating oil quantity after aging.
As shown in figure 5, for the correlativity curve of oil mass and rail pressure of the fuel system injector under distinct pulse widths, by It is found that after pulsewidth determination, distributive value will change Fig. 5 with the variation of rail pressure.During oil mass estimates multi-injection, with Each fuel injection, rail pressure when injection continuously decreases, and therefore, the starting rail pressure sprayed each time is different, can from Fig. 5 Know, although injection pulse width is identical, the change of starting rail pressure will cause distributive value to generate variation.If not considering rail pressure dynamic The influence of decline then always sprays estimation oil mass Q in acquisition injectorTotal sprayAfterwards, initial spray can be directly calculated according to injecting times N Penetrate P under rail pressureInitiallySingle distributive value QEstimation, QEstimation=QTotal spray/ N, still, due to the decline of initial injection rail pressure, actually QTotal sprayIt removes It obtains being the mean rail pressure P during rail pressure dynamic declines with NmCorresponding average injection oil mass Qm, need according to current driving Oil mass uses mean rail pressure P with the variation relation of rail pressure under pulsewidthmSeek correction factor α, and to QmIt is modified, can just obtain Obtain initial injection rail pressure PInitiallyUnder practical single injection event oil mass QEstimation.Specifically, since oil mass can be with the variation relation of rail pressure It embodying in Q2T tables, therefore after driving pulsewidth to fix, distributive value can be obtained by looking into Q2T tables according to rail pressure, i.e. Q=Map (P), So correction factor α=Map (PInitially)/Map(Pm), then the single distributive value Q under initial injection rail pressureEstimation=α * Qm=α * QTotal spray/N =α * (QAlways–QIt is total to return)/N。
Calculate P used when αmFor average injection oil mass QmCorresponding rail pressure, one is preferably sought PmEmbodiment be Set PmIt is the average value of front and back the acquired rail pressure of oil mass estimation multi-injection.It is, of course, preferable to which the description of embodiment is in nature It is only exemplary and be in no way intended to limit the present invention, it also other distinct methods can be used to seek Pm.Due to first The basic oil mass pulse width conversion table Q2T of standard injector is used during secondary oil mass estimation self study, for each injector For, accuracy is also insufficient, therefore calculates the correction factor α obtained for the first time with certain deviation, but with for the first time The completion of oil mass self study, second of estimation oil mass will use newer each individual Q2T of injectoriTable corrects system to calculate Number α, after iteration several times, the accuracy of correction factor α will be promoted gradually, and the precision of small oil mass estimation also will be carried further It rises.
As shown in fig. 6, to drop estimation distributive value and the modified algorithm schematic diagram of pulsewidth based on rail pressure.When meeting working condition Afterwards, step 602 opens oil mass estimation study, and in engine normal operation, complete the oil mass estimation of injector to be measured with from Study.Due to injection pulse width be long enough that injector needle-valve is opened, rail pressure drop at this time is common with recirculating oil quantity by distributive value It constitutes, the rail pressure of the total oil mass of step 607 acquisition and recording drop, and the total estimation of related coefficient conversion for acquisition of being tabled look-up according to step 606 Oil mass QAlways；Total estimation oil mass, which subtracts the recirculating oil quantity that step 608 calculating obtains, can calculate total injection estimation oil mass Q of injectorTotal spray, Carried out rail pressure dynamic descent coefficient amendment and divided by injecting times after final single distributive value Q can be obtainedEstimation。
As shown in fig. 7, for the oil mass characteristic curve aging schematic diagram of certain injector, wherein curve 1 is serial fuel injector Basic oil mass characteristic curve, the actual oil mass characteristic curve of fuel injector when curve 2 is manufacture, curve 3 are the fuel injector aging Oil mass characteristic curve afterwards；Deviation factor 1 is that oil mass characteristic when certain fuel injector dispatches from the factory is characteristic relative to basic oil mass Deviation, deviation factor 2 are the oil mass characteristic after certain fuel injector aging relative to the characteristic deviation of basic oil mass.In different works The multi-injection driving pulsewidth that condition point looks into Q2T tables when implementing oil mass estimation function to determine according to rail pressure and basic oil mass, and with This pulsewidth drives the continuous n times injection of injector, and carries out oil mass estimation to obtain single injection event oil mass QEstimation, fall into a trap in step 609 Deviation factor γ of the estimation oil mass relative to basic oil mass is calculated, whereinAnd deviation factor filling is tested spray In the oil mass deviation factor learning table of emitter.According to the oil spout precision of project demand, define in oil mass deviation factor learning table Study operating point number (is generally deleted on the basis of basic Q2T tables operating point, learns operating point defined in this specification Number is identical as Q2T table operating points) to be balanced in learning efficiency and oil mass precision aspect.Deviation factor is compared and may be used also With the accuracy that oil amount determination is estimated, after calculating obtains certain operating point deviation factor, if it find that this deviation factor is much larger than The deviation factor of other operating points or this deviation factor for calculating acquisition obtain much larger than the last time with condition calculating inclined When poor coefficient, the accuracy of oil mass estimation will be under suspicion, and ECU recalculates the deviation factor of confrontation doubtful point again.
The dotted curve of injector deviation factor in Fig. 71,2 represents injector relative to the inclined of basic fuel injection characteristic Poor degree, but the two has difference again.The dotted curve of deviation factor 1 represents the oil mass characteristic phase when manufacture of certain fuel injector For the characteristic deviation of basic oil mass；The dotted curve of deviation factor 2 represents the oil mass characteristic phase after certain fuel injector aging For the characteristic deviation of basic oil mass.In the step 602 of Fig. 6, there are two types of the conditions of unlatching oil mass self study, the first Condition is that engine or vehicle just dispatch from the factory, and fuel injector never carries out oil mass estimation study, carries out injector oil mass self-study at this time It is to determine departure degree γ of each injector oil mass compared to basic oil mass to practise the purpose for obtaining deviation factorManufacture, to carry out Small oil mass compensation control, deviation factor 1 are such situation；The second situation is the injection characteristics when aging occurs in injector Curve will totally shift, though oil mass estimation study is had been carried out at this time, in order to determine what aging generated oil spout curve It influences, again estimating injector oil mass deviation factor γAging, to meet the modified needs of fuel injector aging, deviation factor 2 is Such situation.Therefore drift delta γ (Δ γ=γ of above-mentioned two deviation factor can be usedAging-γManufacture) characterize injector Degree of aging.Invention defines bias drift degradation failure threshold values, and by oil mass deviation factor drift delta γ and degradation failure Threshold value is compared, and when finding that deviation factor has drifted beyond degradation failure threshold value, fuel injector degradation failure has occurred in surface, Driver can be reminded to need timely processing.
In step 602, in opening fuel injector aging and correcting the condition calculating of oil mass self study, in order to determine aging amendment Opportunity, other than being judged in addition to the mileage number that uses the last aging amendment of distance to pass through or engine on time, Deviation factor γ when engine is in characteristic operating point operation can also be detected in the characteristic operating point of settingFeature (i), and count Calculate deviation factor γ when it is corrected relative to last agingFeature (i-1)Offset, by judge offset whether be more than aging Correction threshold come determine fuel injector whether need carry out aging amendment；Wherein, characteristic operating point when fuel injector dispatches from the factory into rower It is fixed, it can preferentially select to influence apparent operating point to fuel injector performance or engine operation commonly uses operating point as feature operating mode Point.It is worth noting that, detected this deviation factor γFeature (i), the degree of aging for confirming injector is can also be used to, That is characteristic operating point deviation factor drift value Δ γ '=γFeature (i)-γFeature (manufacture), wherein γFeature (manufacture)It is rigid for engine or vehicle Just when manufacture, in average departure degree of the characteristic operating point relative to basic oil mass, when Δ γ ' has been more than degradation failure threshold value When, it is also weathered serious that fuel injector also can be explained.
It should be noted that the above deviation factor γ and drift value Δ γ seek different methods can be used to complete, A preferred embodiment is listed in the present invention to be described, this embodiment is only exemplary and never in nature It is for limiting application of the invention or using.The present invention has been used in the deviation factor γ for seeking certain fuel injector to each work Deviation factor under condition carries out average method, and with the offset of this average value compared with fault threshold or aging correction threshold Compared with；The other methods for seeking deviation factor characterization value further include being weighted averagely to each operating mode lower deviation coefficient, so that weight The influence of operating point is wanted to increase, or whether the deviation factor drift value for being respectively compared each operating point works as operating mode more than threshold value When 50% or more the deviation factor drift of points is all higher than threshold value, then degradation failure or aging amendment are confirmed as.
Can engine during normal operation, complete injector to be measured oil mass estimation and self study.It is transported in internal combustion engine During row, multi-injection is calculated and implemented using step 605, specifically, the present invention sprays the long pulsewidth of injector to be measured Being divided into the identical short pulse duration of limited n times, continuously injection is sprayed with single compensation, and completes to spray using the mode of multi-injection The ejection function that device is N+1 times.Wherein continuously injection is to carry out oil mass estimation, total oil mass of injection to the identical short pulse duration of n times For Q1；And remaining 1 injection sprays Q2 (it is required that falling in the characteristic linear region of oil mass, to ensure that oil mass is sprayed for compensation The accuracy penetrated), effect, which is to ensure that, keeps the torque before and after oil mass estimation function consistent, compensates distributive value Q2=Qd-Q1+ Δ Q, Wherein Qd is injector demand distributive value, and Δ Q is micro- closed loop adjusting oil mass.
Since injector to be measured carries out small oil mass n times injection, and the injection of self study stage small oil mass is accurate not enough, though Right target is Q1, but there are deviations by actual oil mass affirmative and Q1, in turn result in the total oil mass and other several cylinders of injector to be measured The total oil mass of injector is different, along with the combustion efficiency under multi-injection pattern may also can be impacted, eventually lead to cylinder to be measured Torque and other several cylinders caused by (cylinder belonging to injector i.e. to be measured, same as below) are different, to show as starting The machine fluctuation of speed, vehicle occur running not steady enough or have subtle jitter phenomenon.
To solve the above-mentioned problems, the present invention is used and is carried out to cylinder torque to be measured after opening oil mass self-learning function The method of closed-loop control compensation.Due to the difference of torque produced by each cylinder, it can be embodied on each cylinder transient rotative speed and (need to note Meaning, the torque difference token state of use includes but not limited to transient rotative speed, such as also transient rotative speed increment, cylinder pressure etc. Each cylinder torque difference can be characterized, in the present embodiment by taking each cylinder transient rotative speed as an example), therefore ECU is by detecting each cylinder transient state Rotating speed, and then cylinder transient rotative speed to be measured is compared with the average transient rotative speed of non-cylinder to be measured, so that it may with the oil mass to cylinder to be measured Micro- closed loop adjusting is carried out, so that cylinder torque to be measured is identical as other cylinders, or the control of the torque difference of cylinder to be measured and other cylinders is existed In small range, this small torque difference is usually that allow and driver is inconspicuous.
Specific implementation steps are, after opening oil mass self study, ECU opens each cylinder transient rotative speed detection of engine immediately Function, and calculate cylinder transient rotative speed N to be measuredTransient stateRelative to non-cylinder transient rotative speed mean value N to be measuredIt is averageDifference, discrepancy delta NDifference= |NTransient state-NIt is average|.Speed difference threshold value can be determined by rating test, as Δ NDifferenceWhen less than threshold value, vehicle even running；Conversely, As Δ NDifferenceWhen more than threshold value, then it is assumed that vehicle operation is unstable, needs the micro- closed-loop control of torque for carrying out cylinder to be measured, ECU according to ΔNDifferenceTo calculate adjusting oil mass Δ Q (specifically, can be with Δ NDifferenceΔ Q is calculated by the method for PID control for feedback quantity, But be not restricted to that such method.), and then closed loop adjusts cylinder compensation distributive value Q2 to be measured so that Δ NDifferenceLess than threshold value, then table Show that cylinder to be measured is consistent with other each cylinder torques, so that it is guaranteed that vehicle energy even running when opening oil mass self study.
As shown in figure 8, to update certain injector oil mass pulse width conversion table Q2TiSchematic diagram, complete oil mass estimation with oil After measuring deviation factor self study, it can be come in step 610 using the oil mass deviation factor learning table of basic Q2T tables and each injector Obtain the oil mass pulse width conversion table Q2T of each injector alonei, to carry out the oil mass compensation of small oil mass nonlinear area.In general, Oil mass pulse width conversion table Q2TiReference axis be consistent with operating point number and oil mass deviation factor learning table, be initialized as Pulse-width data in basic oil mass Q2T tables.After completing oil mass deviation factor learning table, first, oil mass deviation system can be used Learning table is counted to calculate the estimation oil mass in Q2T tables under some rail pressure corresponding to each oil mass coordinate operating point, i.e. QEstimation=(1+ γ)*QSubstantially, wherein QSubstantiallyFor each oil mass coordinate value in basic Q2T fuel level gauges；It thus obtains and reflects under current rail pressure It estimates oil mass and drives the interim estimation oil mass inquiry table of relationship between pulsewidth；It is finally used further according to estimation oil mass inquiry table slotting The method of value calculates Q2TiPractical driving pulsewidth in table under current rail pressure corresponding to each oil mass coordinate operating point.Each Above method is repeated under rail pressure coordinate value, you can complete the corresponding Q2T of fuel injector to be measurediThe update of table.
As shown in figure 8, the present invention is listed according to certain fuel injector oil mass deviation factor learning table and basic oil mass Q2T characteristics Table determines the Q2T of fuel injector to be measurediOne embodiment of practical driving pulsewidth of the table in 50bar.First, according to deviation system Number learning table determines each estimation oil for being sprayed and being obtained with each driving pulsewidth in basic Q2T property lists when 50bar Amount；The interim estimation oil mass for thus obtaining relationship between reflection estimation oil mass and driving pulsewidth under current 50bar rail pressures is looked into Table is ask, but each point oil mass coordinate value of this estimation oil mass inquiry table and each point oil mass coordinate value in basic Q2Ti tables are not With, therefore finally also need to seek basic Q2T by the method for interpolation according to estimation oil mass inquiry tableiEach point in table The corresponding driving pulsewidth of oil mass coordinate value, and backfill into Q2TiIn row under the corresponding rail pressure 50bar of table, original pulsewidth number is covered According to.Above method is repeated under each rail pressure coordinate value, you can complete the entire Q2T of current fuel injectoriThe update work of table.
Finally, the control of the oil correct under small oil mass nonlinear area is carried out to fuel system.As shown in fig. 6, in step 601, which do not carry out oil mass, estimates that step 604 is tabled look-up using given basic Q2T tables and seeks fuel injection pulsewidth when learning, and judgement is It is no to need to carry out oil mass estimation self study.And it completes self study in step 603 and obtains the oil mass pulsewidth of each injector alone turn Change table Q2TiAfterwards, Q2T can be usediTable tables look-up to obtain revised fuel injection pulsewidth, to ensure the consistent of the small oil mass injection of injector Property.When needing to carry out compensation of ageing, oil mass estimation study still can be carried out again, to be modified to the aging of injector. Before aging amendment study is completed, the former Q2T that is obtained using step 610iTable obtains final fuel injection pulsewidth, aging amendment study After the completion, then newer Q2T is usediTable acquisition eventually passes through again modified fuel injection pulsewidth.
The present invention is different from solution existing in the prior art as follows：
(1) in order to improve the accuracy of injector oil mass estimation to be measured, (horse Rayleigh is public for solution of the existing technology Department) method of statistics has been used to ensure that it is correct that rail pressure drop calculates, although after estimating at hundreds of, estimation oil mass can be accurate to In ± 0.1mg.But this method greatly reduces the operational efficiency of algorithm, has aggravated the data processing load of ECU.
The present invention has carried out multiple rail pressure acquisition afterwards before ejecting, and sentences to the extent of deviation of these rail pressure collection values It is disconnected, reject the rail pressure collection point that deviation is more than threshold value.Only after collecting multiple deviation degree smaller rail pressure collection value, It can confirm the front and back rail pressure final output mean value of acquisition；The present invention equally carries out the rail pressure drop extent of deviation being repeatedly calculated Judge, dropped more than the rail pressure of threshold value with rejecting deviation, after only collecting the smaller rail pressure drop of enough extent of deviation, Calculate rail pressure drop final output mean value.The method is the accuracy that ensure that rail pressure acquisition and calculated with rail pressure drop in source, is kept away Having exempted from big data statistical disposition reduces algorithm operational efficiency.
(2) solution (horse Rayleigh company) in the prior art is chosen four characteristic point P1-P4 and is carried out under each rail pressure The determination of rail pressure drop estimation oil mass, wherein characteristic point P1 and P2 is in small oil mass nonlinear area, and P3 and P4 is in oil mass line Property region, using 4 points two straight lines can approximate accurately reconstruct injector jet law.The computational methods that horse Rayleigh uses It is to estimate oil mass absolute value to reconstruct fuel injection characteristic, but oil mass absolute magnitude can not illustrate injector relative to basic oil mass characteristic The extent of deviation of curve.
In order to overcome this deficiency, the present invention to devise the oil mass deviation factor learning table of each injector, obtaining one Orbit determination is pressed and the single injection event estimation oil mass Q under pulsewidthEstimationAfterwards, deviation factor γ of the estimation oil mass relative to basic oil mass is calculated, WhereinThen deviation factor is inserted in the oil mass deviation factor learning table of test injector.It can be according to reality Oil spout precision required by border ejector characteristics curve condition and project, to define the operating point in oil mass deviation factor learning table Number (is generally deleted on the basis of basic oil mass Q2T table operating points), in learning efficiency and fuel-flow control accuracy side Face is balanced.The deviation factor of injector represents extent of deviation of the injector relative to basic Q2T injection characteristics, works as injection When aging occurs in device, injection characteristics curve totally shifts, and with the increase of degree of aging, whole extent of deviation will not Disconnected drift becomes larger, therefore the drift value Δ γ of deviation factor can be used to characterize the degree of aging of injector, invention defines Aging threshold, and the drift value Δ γ of deviation factor is compared with aging threshold, the deviation factor under each operating mode of discovery When drift is more than aging threshold, driver's injector serious aging can be reminded.Meanwhile oil mass can also be estimated using deviation factor Accuracy judged, if carry out oil mass estimation study after, it is found that the deviation factor that acquisition is calculated under certain operating mode is long-range It is obtained with condition calculating much larger than the last time in the deviation factor of other operating points or this deviation factor for calculating acquisition When deviation factor, the accuracy of oil mass estimation will be under suspicion, and ECU is counted the deviation factor of confrontation doubtful point again again It calculates.
(3) when oil mass self-learning algorithm implements the injection under multiple same pulse width, with each fuel injection, when injection Rail pressure continuously decrease, therefore, the starting rail pressure P sprayed each timeInitiallyIt is all different, which results between each injection Distributive value will produce difference, and horse Rayleigh patent does not consider the starting rail pressure difference sprayed every time during multi-injection to oil mass Influence, only according to formula Q=QAlways/ N sprays rail pressure P to calculate most initialInitiallyUnder single distributive value Q.The present invention then recognizes For, it is different due to originating rail pressure although driving pulsewidth is identical, it can not be simply by QAlways/ N is sprayed as most initial under rail pressure Actual ejection oil mass.This is to say, QAlwaysDivided by N obtain be rail pressure dynamic decline during mean rail pressure PmCorresponding Averagely injection oil mass Qm, therefore obtaining QmAfterwards, it needs to be used with the variation relation of rail pressure according to oil mass under current driving pulsewidth flat Equal distributive value QmCorresponding rail pressure PmIt is modified, most initial injection rail pressure P could be obtainedInitiallyUnder actual ejection oil mass QEstimation.By It can be embodied in Q2T tables with the variation relation of rail pressure in oil mass, therefore after driving pulsewidth to determine, look into Q2TiBiao Ke get Distributive value, i.e. Q=Map (P), then correction factor α=Map (PInitially)/Map(Pm), then the single oil spout under initial injection rail pressure Measure Q=α * Qm.Correction factor α when due to first time oil mass self study is according to primary standard injector master data Q2T tables Lattice and calculate, and standard injector and the performance data of each single injector are different, therefore first time oil mass self study When the correction factor α that calculates there is certain error, but with the completion of first time oil mass self study, second of self study will adopt With newer each single individual Q2T of injectoriTable calculates correction factor α, after the iteration of self study several times, repaiies The accuracy of positive coefficient α will be gradually increased, and the precision of small oil mass estimation also will be promoted further.
(4) solution (Bosch) in the prior art is thought, the pulsewidth not open injector needle-valve drives spray Emitter, at this time without oil spout, rail pressure drop is caused by oil return completely, can determine recirculating oil quantity by measuring rail pressure drop；And normal When injection, total oil mass Q that rail pipe flows out after determining the injection of the injector under current working is dropped by rail pressureAlways, last injector Spray oil mass QTotal spray=QAlways–QIt is total to return.Although Bosch to the calculating of recirculating oil quantity and distributive value be carried out condition with it is general on direction It states, but does not refer to the specific steps of implementation specifically.And another solution (horse Rayleigh company) then think when rail pressure compared with System will produce fuel loss when high, can estimate it, and the influence of fuel loss is deducted when estimating distributive value.First It determines the first fuel loss, loses direct ratio in the duration of measurement, then determine the second fuel loss, this loss is straight Ratio is connect in the unlatching number of fuel injector, finally by being added the two values to obtain fuel quantity loss.Obvious horse Rayleigh Processing method about fuel loss estimation is fairly simpleization, does not also account for influence of the injector aging to leakage.
For theoretically, fuel system leakage is the abnormality of system, should generally avoid the generation of leakage as possible, but real Fuel system unavoidably will produce leakage on border, and invention is thought before carrying out oil mass self study, it should be ensured that fuel system Leakage rate is met the requirements, specifically, under the operating mode (such as vehicle Overrun operating modes) that injector does not spray, forbids spray pump oily, this When fuel system in without oil inlet with it is fuel-displaced, the rail pressure that ECU is detected declines at any time mainly fuel system leak caused by, remember It records under different rail pressures, the rail pressure drop in the unit interval, and inserts in the fuel leakage rail pressure petition of surrender.Before oil mass self study, need The rail pressure drop in the fuel leakage rail pressure petition of surrender is obtained according to current rail pressure, and event is dropped with the rail pressure under the current rail pressure of predefined Hinder threshold value comparison and just thinks that fuel system leakproofness is met the requirements when only in-orbit pressure drop is less than threshold value.Even if the unit interval fires Oil system leakage is less than threshold value, and in order to ensure the accuracy of oil mass estimation, rail pressure drop Δ P ' is calculated in oil mass self study Afterwards, still it can be modified using fuel system leakage rate, specific method is to leak rail pressure drop according to the unit interval To calculate the drop Δ of the fuel leakage rail pressure under the injector fuel injection pulsewidth duration to be measured PLeakage, then fuel leakage influence is eliminated Δ P=Δs P '-Δ P drops in rail pressureLeakage.It should be noted that the rail pressure drop such as the Δ P, Δ P that are referred in textOil returnEtc. be deduct The rail pressure drop of fuel system leakage.
In the present invention, it is determined using the mode of experiment under certain rail pressure, the corresponding recirculating oil quantity of certain injection pulse width, and handle This recirculating oil quantity is inserted in recirculating oil quantity inquiry table；Therefore, in the ideal case, it can be tabled look-up according to rail pressure and injection pulse width and obtain single The recirculating oil quantity of injection, i.e. QOil return=Map (P, L).And in real engine operational process, each injector can gradual aging, this leads The recirculating oil quantity of each injector is caused to generate creep, tabling look-up the recirculating oil quantity sought at this time will be no longer accurate.The present invention proposes a kind of side Method, to determine the recirculating oil quantity after injector aging.Specific method is, in operating mode (such as vehicle towing astern operating mode that injector does not spray Or scavenging stroke) under, injector multi-injection to be measured is triggered with Standard pulse-width, the cause of injector needle-valve can not be opened under this pulsewidth Dynamic injector, but the oil return of injector can occur, acquire and calculate the drop Δ of the oil return rail pressure under Standard pulse-width POil return, and according to phase Relationship number is scaled the oil return estimator Q under Standard pulse-widthEstimate oil return.When aging occurs for injector, QEstimate oil returnIt is looked into Standard pulse-width Table recirculating oil quantity QBasic oil returnDifference will be generated, definition oil return aging factor is λ
After oil return aging factor is determined, invention devises the specific implementation step for determining injector oil mass to be measured. When engine normal operation, injector injection to be measured is triggered using the method for multi-injection, since injection pulse width is long enough that It obtains injector needle-valve to open, rail pressure drop at this time is collectively formed by distributive value and recirculating oil quantity, acquires and record the rail of total oil mass Pressure drop and the total oil mass Q for being scaled the outflow of rail pipeAlways；According to pulsewidth and the basic recirculating oil quantity of rail pressure computation of table lookup, and it is old according to oil return Change factor pair fuel system oil return QIt is total to returnIt is modified, to confirm that recirculating oil quantity after injector aging, total injection of last injector are estimated Calculate oil mass QTotal spray=QAlways–QIt is total to return。
(5) in order to ensure oil mass self-learning function, current solution (Ma Rui can be executed in engine normal operation Sharp company) it is to record total oil mass of multi-injection first after executing multi-injection as Q1；Execute single compensation spray again later It penetrates, distributive value is Q2 (Q2=Qd-Q1, wherein Qd are injector demand distributive value), to supply the deficiency of distributive value.Due to be measured Injector carries out small oil mass multi-injection, and the injection of self study stage small oil mass is accurate not enough, although target is Q1, Actual oil mass is certainly and Q1 is there are deviation, in turn results in total oil mass of injector to be measured with other a few total oil masses of cylinder injector not Together, add multi-injection pattern under combustion efficiency may also can be impacted, eventually lead to cylinder to be measured (injector institute i.e. to be measured It is the cylinder of category, same as below) caused by torque and other several cylinders it is different, to show as the signal waves such as engine speed Dynamic, vehicle occurs running not steady enough or has subtle jitter phenomenon.
To solve the above-mentioned problems, the present invention is used and is carried out to cylinder torque to be measured after opening oil mass self-learning function The method of closed-loop control compensation.Due to the difference of torque produced by each cylinder, it can be embodied on each cylinder transient rotative speed and (need to note Meaning, the torque difference token state of use includes but not limited to transient rotative speed, such as also transient rotative speed increment, cylinder pressure etc. Each cylinder torque difference can be characterized, in the description by taking each cylinder transient rotative speed as an example), therefore ECU is turned by detecting each cylinder transient state Speed, and then cylinder transient rotative speed to be measured is compared with the average transient rotative speed of non-cylinder to be measured, so that it may with the oil mass to cylinder to be measured into Micro- closed loop of row Δ Q is adjusted, so that cylinder torque to be measured is identical as other cylinders, or the torque difference of cylinder to be measured and other cylinders is controlled In small range, this small torque difference is usually that allow and driver is inconspicuous.
Specific implementation steps are that after opening oil mass self study, ECU opens each cylinder transient rotative speed of engine or wink immediately The detection function of state incremental speed, and calculate cylinder rotating speed N to be measuredTransient stateRelative to non-cylinder transient rotative speed mean value N to be measuredIt is averageDifference, Its discrepancy delta NDifference=| NTransient state-NIt is average|.Speed difference threshold value can be determined by rating test, as Δ NDifferenceWhen less than threshold value, vehicle Even running；Conversely, working as Δ NDifferenceWhen more than threshold value, then it is assumed that vehicle operation is unstable, needs the torque for carrying out cylinder to be measured is micro- to close Ring controls, and ECU is according to Δ NDifferenceTo calculate adjusting oil mass Δ Q (specifically, can be with Δ NDifferencePass through PID control for feedback quantity Method calculates Δ Q, but be not restricted to that such method.), and then closed loop adjusts cylinder compensation distributive value Q2 (Q2=at this time to be measured Qd-Q1+ Δ Q) so that Δ NDifferenceLess than threshold value, then it represents that cylinder to be measured is consistent with other each cylinder torques, so that it is guaranteed that opening oil mass Vehicle energy even running when self study.

Claims (9)

1. a kind of small fuel-flow control method of fuel injector, it is characterized in that：The control method is multiple using injector to be measured The front and back rail pressure of small oil mass injection drops to carry out oil mass estimation, and the basic oil mass characteristic curve of estimation oil mass and injector into Row compares, and obtains its deviation factor relative to basic oil mass, is then filled in oil mass deviation factor learning table；Complete oil mass After the study of deviation factor learning table, each injector is sought in the small corresponding deviation factor of oil mass nonlinear area applying working condition Oil mass pulse width conversion table Q2T alonei, and use revised Q2TiAcquisition of tabling look-up eventually passes through modified injection pulse width；Specifically Include the following steps：
(1) oil mass self study, which is opened, judges：Judge whether fuel injector needs to open oil mass self-learning function；
(2) oil mass estimation is enabled judges：After opening oil mass self-learning function, external condition judgement is carried out：Whether assess vehicle Meet the external status or working condition requirement of oil mass estimation；And carry out interior condition judgement：Fuel system leakproofness is examined It surveys to judge whether fuel system meets oil mass estimation inner sealing requirement；After inner and exterior conditions all meet, oil mass is enabled Estimation function；
(3) rail pressure acquires before oil spout：After enabled oil mass estimation function, pump oil function and oil spout function are closed, in fuel system In the case that no fuel oil input and output and rail pressure are stablized, the rail pressure acquisition before injector injection to be measured starts and acquisition rail pressure are carried out Reasonability judges；
(4) injector sprays：Before completing to spray after rail pressure acquisition, the ejection function of injector is executed, selectes suitable injection Number and injection pulse width are touched in the case where closing pump oil and other cylinder not oil spouts in addition to cylinder to be measured using multi-injection pattern It sends out injector to be measured and executes N+1 injection, include the continuous injection of the identical short pulse duration of n times, and another plus 1 micro- closed loop compensation sprays It penetrates；
(5) rail pressure acquires after oil spout：After injector completes the continuous injection of the identical short pulse duration of n times, injection to be measured is carried out again Rail pressure acquisition after device injection judges with rail pressure acquisition reasonability；
(6) rail pressure drop calculates：According to the front and back pressure difference of injection, calculate the injection rail pressure drop of injector to be measured, to rail pressure drop into Row reasonability judges, to obtain final rail pressure drop output mean value；
(7) total oil mass is estimated：According to the rail pressure drop mean value and related coefficient being calculated, the rail estimated under current working is sought Pipe flows out total oil mass QAlways；
(8) recirculating oil quantity is calculated：Experiment determines different rail pressures basic recirculating oil quantity corresponding with driving pulsewidth before injector dispatches from the factory, And insert basic recirculating oil quantity table；The oil return aging factor λ under different rail pressures is calculated, and using aging factor to basic recirculating oil quantity Table is modified, to obtain the recirculating oil quantity after aging；
(9) single injection event oil mass is estimated：Total oil mass Q is flowed out according to the rail pipe estimated under current workingAlwaysWith recirculating oil quantity QIt is total to returnCalculating is worked as The single injection event estimation oil mass Q of preceding injector to be measuredEstimation, QEstimation=α * (QAlways–QIt is total to return)/N, wherein α are that rail pressure dynamic declines to single The correction factor of oil mass is sprayed, N is injecting times；
(10) oil mass deviation factor learning table updates：It obtains the single estimation that different rail pressure differences correspond under pulsewidth and sprays oil mass QEstimation, and deviation factor γ of the estimated single injection event oil mass relative to basic oil mass is calculated, and update the oil mass of each injector Deviation factor learning table；
(11) fuel injector degradation failure：According to the oil mass deviation factor γ after fuel injector agingAgingPass through oil mass when relative to manufacture The deviation factor γ that self study obtainsManufactureDrift value Δ γ to judge fuel injector degree of aging, and carried out with preset failure threshold value Compare, to determine whether fuel injector occurs degradation failure；
(12) fuel injection pulsewidth is coordinated：After completing self study, the revised oil of each injector is obtained according to oil mass deviation factor Pulse width conversion table is measured, and looks into revised oil mass pulse width conversion table and obtains the revised injection pulse width of final process.
2. the small fuel-flow control method of fuel injector as described in claim 1, it is characterized in that：What the oil mass self study was opened Condition had never carried out oil mass self study since including this group of injector manufacture or had carried out oil mass self study but needed to spray Emitter carries out aging amendment；The modified oil mass self study unlocking condition of aging includes that engine is corrected in the last aging of distance Having run certain time not only corrects vehicle apart from last aging but also has travelled certain mileage or under characteristic operating point Open the offset of deviation factor when this detected deviation factor of oil mass estimation function is corrected relative to last aging Amount is more than the modified threshold value of aging.
3. the small fuel-flow control method of fuel injector as described in claim 1, it is characterized in that：It is opened in the oil mass self study Afterwards, external condition and interior condition are judged；The external Rule of judgment includes that vehicle operates in unfaulty conditions, rail pressure Sensor acquires fault-free, power source supplying voltage stabilization, rail pressure fluctuation range and is less than threshold value and stablizes more than a period of time；It is described Interior condition judgment method is：Vehicle be in forbid spray pump oil make fuel system without oil inlet with it is fuel-displaced in the state of, record is different Under rail pressure, rail pressure in unit interval drop, and complete the update of rail pressure drop leakage table, by under current rail pressure rail pressure drop in advance The current rail pressure lower rail pressure drop leak threshold of definition compares, when rail pressure drop is less than threshold value, it is believed that in fuel system leakproofness meets Portion's Rule of judgment.
4. the small fuel-flow control method of fuel injector as described in claim 1, it is characterized in that：Before oil mass estimation, make It is modified with fuel system leakage rail pressure drop, specific method is dropped according to unit interval fuel leakage rail pressure to count It calculates under current rail pressure, the fuel leakage pressure drop Δ P under the injector fuel injection pulsewidth duration to be measuredLeakage, using leakage rail pressure, Δ drops PLeakageUsed rail pressure drop, which is modified, to be estimated with recirculating oil quantity to injector distributive value to be measured estimation, is led with removing fuel leakage The rail pressure drop of cause influences, and enhances estimation precision.
5. the small fuel-flow control method of fuel injector as described in claim 1, it is characterized in that：In enabled oil mass estimation function Afterwards, signal is characterized by detecting each cylinder torque difference, and then cylinder torque to be measured is compared with non-cylinder average torque to be measured, with Implement micro- closed-loop control to cylinder oil mass to be measured to adjust, to obtain micro- closed loop adjusting oil mass △ Q of cylinder to be measured, reaches each cylinder torque Coherence request.
6. the small fuel-flow control method of fuel injector as described in claim 1, it is characterized in that：Lead to oil return in injector aging After amount offset, using oil return aging factor, basic oil return scale is compensated and corrected；Calculating acquisition aging factor condition is： Vehicle is in the state for not needing injector work, and the oil mass for triggering injector to be measured with Standard pulse-width in this case estimates work( Can, this Standard pulse-width can not open injector needle-valve actuating injector, but will produce the oil return of injector, then oil return aging factor λ is to estimate recirculating oil quantity and the ratio for the basic recirculating oil quantity of acquisition of tabling look-up according to Standard pulse-width, i.e. λ=QEstimate oil return/QBasic oil return, obtain different Aging factor under rail pressure, and basic oil return scale is modified using aging factor under each rail pressure, after obtaining aging Recirculating oil quantity.
7. the small fuel-flow control method of fuel injector as described in claim 1, it is characterized in that：The rail pressure dynamic declines to list The finding process of correction factor α of secondary injection oil mass is：Rail pressure continuously decreases in course of injection, and actual ejection oil mass is caused to be Mean rail pressure P during declining relative to rail pressure dynamicmAverage injection oil mass Qm, using correction factor α to QmIt is modified, To obtain initial injection rail pressure PInitiallyUnder single injection event oil mass QEstimation；When driving pulsewidth to fix, looking into Q2T tables according to rail pressure can obtain Distributive value, i.e. Q=Map (P), then correction factor α=Map (PInitially)/Map(Pm)；Using successive ignition seek the method for α with Improve precision.
8. the small fuel-flow control method of fuel injector as described in claim 1, it is characterized in that：Obtain different rail pressures and substantially oil Single injection event estimation oil mass Q under the corresponding driving pulsewidth of amountEstimationAfterwards, deviation system of the estimation oil mass relative to basic oil mass is calculated Number γ, wherein γ=(QEstimation-QSubstantially)/QSubstantially, and deviation factor is inserted according to basic oil mass and rail pressure the oil mass for testing injector In deviation factor learning table.
9. the small fuel-flow control method of fuel injector as described in claim 1, it is characterized in that：When unfinished oil mass self study When, the injection pulse width when acquisition of Q2T tables does not learn is looked into according to rail pressure and oil mass；After completing to learn, injector can be used respectively Oil mass pulse width conversion table table look-up obtain study after injection pulse width；The Q2T of each injectoriThe determination method of table is：First, root According to oil mass deviation factor learning table, the estimation oil mass under some rail pressure corresponding to each oil mass coordinate value in basic Q2T tables is determined, That is QEstimation=(1+ γ) * QSubstantially；It thus obtains under current rail pressure reflection estimation oil mass and drives the interim of relationship between pulsewidth Estimate oil mass inquiry table；Further according to estimation oil mass inquiry table, current injector Q2T is calculated using the method for interpolationiIn table when Front rail depresses the practical driving pulsewidth corresponding to each oil mass coordinate value；Above method is repeated under different rail pressures, you can complete The corresponding Q2T of fuel injector to be measurediThe update of table.
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CN112096535A (en) * 2020-08-13 2020-12-18 东风汽车集团有限公司 Engine fuel injection frequency control method and system and automobile
CN113931760A (en) * 2021-09-26 2022-01-14 东风商用车有限公司 Power-on pulse width correction verification method and system for gas engine nozzle
CN114021313A (en) * 2021-10-21 2022-02-08 联合汽车电子有限公司 Self-learning method and device for hybrid vehicle and storage medium
CN114658542A (en) * 2022-03-24 2022-06-24 无锡威孚高科技集团股份有限公司 Non-road engine fault detection method based on oil quantity consistency of oil injector
CN114941601A (en) * 2022-06-10 2022-08-26 潍柴动力股份有限公司 Method and device for detecting consistency of oil sprayer
CN115596567A (en) * 2022-10-26 2023-01-13 东风商用车有限公司（Cn） A method, device, equipment and storage medium for self-adaptive compensation of fuel injection quantity
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CN109915271B (en) * 2019-02-21 2021-08-13 浙江吉利控股集团有限公司 Control method of methanol engine fuel injection amount, electronic control unit and vehicle
CN109915271A (en) * 2019-02-21 2019-06-21 浙江吉利控股集团有限公司 A kind of control method, electronic control unit and the vehicle of methanol engine fuel injection amount
CN111120130B (en) * 2019-11-19 2022-06-28 潍柴动力股份有限公司 Engine emission correction method and system
CN111042939A (en) * 2019-11-19 2020-04-21 潍柴动力股份有限公司 Method for measuring fuel injection quantity of engine and engine
CN111120130A (en) * 2019-11-19 2020-05-08 潍柴动力股份有限公司 Engine emission correction method and system
CN110987473A (en) * 2019-12-06 2020-04-10 辽宁龙马安泰网络技术有限责任公司 Distance correction method for transient fuel or waste gas of automobile bench test
CN110987473B (en) * 2019-12-06 2021-04-20 辽宁龙马安泰网络技术有限责任公司 Distance correction method for transient fuel or waste gas of automobile bench test
CN110985224A (en) * 2019-12-16 2020-04-10 潍柴动力股份有限公司 Method and system for judging working state of oil sprayer at initial starting stage of diesel engine
CN110985224B (en) * 2019-12-16 2022-08-23 潍柴动力股份有限公司 Method and system for judging working state of oil sprayer at initial starting stage of diesel engine
CN111520247A (en) * 2020-03-25 2020-08-11 吉利汽车研究院（宁波）有限公司 Method and system for determining air-fuel ratio based on injection pulse width of oil injector
CN111894781A (en) * 2020-06-30 2020-11-06 中国北方发动机研究所(天津) Test method for judging maximum lift of needle valve
CN112096535A (en) * 2020-08-13 2020-12-18 东风汽车集团有限公司 Engine fuel injection frequency control method and system and automobile
CN113931760A (en) * 2021-09-26 2022-01-14 东风商用车有限公司 Power-on pulse width correction verification method and system for gas engine nozzle
CN113931760B (en) * 2021-09-26 2023-09-29 东风商用车有限公司 Power-on pulse width correction verification method and system for gas engine nozzle
CN114021313A (en) * 2021-10-21 2022-02-08 联合汽车电子有限公司 Self-learning method and device for hybrid vehicle and storage medium
CN114021313B (en) * 2021-10-21 2024-08-02 联合汽车电子有限公司 Hybrid vehicle self-learning method, device and storage medium
CN114658542A (en) * 2022-03-24 2022-06-24 无锡威孚高科技集团股份有限公司 Non-road engine fault detection method based on oil quantity consistency of oil injector
CN114941601A (en) * 2022-06-10 2022-08-26 潍柴动力股份有限公司 Method and device for detecting consistency of oil sprayer
CN114941601B (en) * 2022-06-10 2023-12-15 潍柴动力股份有限公司 Method and device for detecting consistency of fuel injector
US20240068424A1 (en) * 2022-08-23 2024-02-29 Caterpillar Inc. Onboard diagnosis and compensation for tip wear in fuel injector
US11994083B2 (en) * 2022-08-23 2024-05-28 Caterpillar Inc. Onboard diagnosis and compensation for tip wear in fuel injector
CN115596567A (en) * 2022-10-26 2023-01-13 东风商用车有限公司（Cn） A method, device, equipment and storage medium for self-adaptive compensation of fuel injection quantity
CN115596567B (en) * 2022-10-26 2025-01-28 东风商用车有限公司 A method, device, equipment and storage medium for adaptive compensation of fuel injection quantity

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