DE10355412B4 - Method and device for optimizing the operation of an internal combustion engine, which is designed with a direct fuel injection system - Google Patents

Abstract

method for optimizing the operation of an internal combustion engine (41), the with a direct fuel injection system is formed, wherein for the optimization of the operation several criteria, in particular regarding the Emissions and comfort, should be considered, characterized in that in advance for a plurality of optimization criteria special map sets be stored, depending on optimal operating values from the driving situation and / or environmental conditions are assigned and that a classifier (1) is formed, the for one current driving situation or ambient condition an optimization criterion selects and then the direct fuel injection system or another affected Control system controls accordingly.

Description

The The invention is based on a method for optimizing the operation an internal combustion engine with a direct fuel injection system of the type the sibling claims 1 and 9 off. For The optimization will be several criteria, especially regarding the Emission behavior and comfort. there be for every single criterion determines optimal parameters and for each Operating point of the internal combustion engine in specific maps saved. With these optimal operating values are then one Direct injection system for Controlled fuel or other affected control systems. Switching between the criteria and thus between the different maps takes place continuously during a driving cycle and such that over the entire driving distance achieved an overall optimum with regard to all essential criteria becomes.

at The known method is usually carried out an optimization strategy in such a way that from a firm Set of maps the "optimal" operating values for each Operating point selected which is always a compromise between many individual criteria, such as Exhaust and noise emissions as well as drivability pose. Thus, for each operating point a rigid "optimum" is firmly applied, with the the control systems of the internal combustion engine or the vehicle to be controlled. However, this compromise provides for the respective Individual criteria results that are considered in particular over an entire driving cycle are only partially optimal. The potential of modern injection methods, especially of multiple injections in diesel engines remains largely unused.

The publication DE 196 37 210 A1 discloses a powertrain control for a motor vehicle in which an integrated powertrain control for a motor vehicle interprets the position of the accelerator pedal and the brake pedal as a desired wheel torque by the driver. The powertrain control has a calculation device, by means of which the position of the accelerator pedal and the brake pedal are received and from which central control parameters for the drive sources and the delaying units of the driveline are generated.

The publication DE 100 62 349 A1 discloses a method and an arrangement for controlling and / or regulating a load of a vehicle to improve a noise emission or noise emission caused by a vehicle. This method or arrangement has a recording unit which determines the instantaneous load of the vehicle based on at least one operating variable of the vehicle, wherein the operating variable is controlled and / or regulated by means of a control unit in dependence on a noise level resulting from the instantaneous load of the vehicle becomes.

The publication DE 296 18 851 U1 discloses a powertrain control for a motor vehicle by which the position of the accelerator pedal is interpreted as a driver desired wheel torque or transmission output torque and used to calculate setpoint values for the engine and the transmission of the vehicle.

Of the Invention is based on the object, a method or to provide a device for optimizing the operation of an internal combustion engine, with the one out of the different, each on a specific criterion optimized map sets Targeted for the respective situation appropriate map set is selected. This object is achieved with the features of the independent claims 1 and 9 solved.

at the method for optimizing the operation of an internal combustion engine with the characterizing features of the independent claims 1 and 9, there is the advantage that the control of the direct injection system for the Fuel or other affected tax systems flexible to the current driving situation and the environmental conditions are adjusted can. It is considered to be particularly advantageous that This results in improved overall engine and vehicle characteristics. The continuous prioritization and switching between different In addition, optimization criteria leads over one whole cycle, with lower emission and consumption levels as well as to improved comfort characteristics of the vehicle than this would be achievable with known optimization methods.

By those in the dependent Claims listed measures are advantageous developments and improvements in the sibling claims 1 and 9 specified method or the device for Optimization of the operation of the internal combustion engine given. Especially Cheap is that the optimization criteria in each case in sub-criteria be divided and then for these subcriteria optimal operating values are determined. With Optimization to strictly defined subcriteria can be achieved the internal combustion engine or the vehicle even better and more precisely in the control the current driving situation optimal operating point.

As subcriteria, emission behavior is analyzed and evaluated in particular for NO _x emissions, particle emissions and the regeneration mode of a diesel particulate filter, or for comfort, drivability and noise emission. These subcriteria are not only important in terms of minimum consumption and emissions, but must be monitored and controlled in an advantageous manner to meet legal requirements.

to Determination of an optimization criterion for a current driving situation a classifier is used, which selects and prioritizes performs a predetermined algorithm. It has proved to be Advantage shown that the classifier in addition to the environmental conditions For example, also used information of a driver type recognition.

alternative for this it is possible that the classifier only uses information from sensors, For example, as a temperature sensor, oil pressure sensor, knock sensor, Speed sensor, etc. arranged in the region of the internal combustion engine are. With this information can be particularly optimal Operating values for the exhaust emission or fuel consumption at a given determine the requested load.

Furthermore It makes sense that the classifier contains information from facilities of the motor vehicle, in particular a navigation system, a used on radio-based telematics system or the like. For example, the noise emission minimizes the vehicle in particular when driving through a residential area become. Alternatively, in highway driving, e.g. concerning the Fuel consumption are optimized, in urban transport priority in terms of suitable exhaust emission criteria. A particle filter regeneration strategy is mainly on longer Expressway and motorway sections useful. Also can be received road status messages For example, to use the drivability characteristics of Vehicle adapt.

A particularly advantageous solution for the implementation of the optimization method is seen in that the classifier carries out its selection and prioritization strategy according to the fuzzy method. The In this context, fuzzy method has the advantage that out the variety of input variables by their picture on blurred Quantities and subsequent Application of suitable fuzzy rules very comfortable on a discrete Value of the output variable "optimization criterion" can be closed can. This makes it easy to classify the classifier suitable criterion for select the current driving situation.

In In this context, it still seems favorable that optimal operating values for vehicle, Engine or ambient conditions be determined, which optimizes exhaust emission, a minimum Fuel consumption, optimum driving comfort, minimal driving noise or a Relate to regeneration of the particulate filter.

at the device for optimizing the operation of an internal combustion engine There is the advantage that this is for direct injection systems of Gasoline, diesel and gas engines can be used. In these Engines usually become activates a multiple injection within one injection cycle, which is controlled by the electrically controlled piezoelectric or magnetic Injectors largely decoupled from the crankshaft angle. Thereby can be very easily almost all possible injection conditions realize and thus for every operating state of the internal combustion engine, the optimal operating point to adjust.

One embodiment The invention is illustrated in the drawing and will be described in the following Description closer explained.

1 shows a schematic representation of a block diagram of the invention,

2 shows an arrangement for a control device according to the invention,

3 shows a block diagram of a classifier,

4 shows a schematic block diagram of the device for optimizing the operation of an internal combustion engine,

5 shows an example of switching between different optimization criteria over a drive cycle and

6 shows simulation examples of how the overall emission behavior over a drive cycle can be improved by means of the method according to the invention.

The invention is applicable to an internal combustion engine designed for direct injection of diesel, gasoline or gas into one or more cylinders. Such internal combustion engines generally use magnetically or piezoelectrically driven injectors with which a multiple injection can also be carried out within one injection cycle. The injected Fuel quantity and the start of injection are calculated by a program-controlled control device as a function of various engine parameters or functions and can be injected directly into the cylinder at the given time and largely decoupled from the crankshaft angle.

In order to obtain optimal operation of the internal combustion engine, it is proposed according to the invention to determine individual operating parameters, such as the emission behavior (exhaust emissions) of the internal combustion engine, comfort, etc., in advance and store them in a suitable form. The optimum operating values are stored as a function of the optimization criteria or partial criteria, preferably in the form of specific characteristic map sets. With regard to the "emission behavior" criterion, the sub-criteria "NO _x emissions" and "particulate emissions" (diesel engine) are to be mentioned, while the criterion "comfort" includes the sub-criteria "driveability" and "noise emission".

aim The invention is an optimization criterion for the operation specify the internal combustion engine, with the of the plurality of individual criteria or the associated optimized map sets the one selected which is best adapted to a current driving situation. In this case, preferably the integral exhaust gas emission values are determined via the entire route taken into account. The selection of the appropriate optimization criterion is carried out with the help of a classifier.

In 1 is a schematic representation of a block diagram in which the function of the classifier 1 is recognizable. The classifier 1 receives at its inputs setpoints that are supplied by various devices of the engine or the vehicle. For example, a torque request is specified by the driver as desired torque TQI_SP. As another function, a vehicle speed VS is input. Further functions are an environmental function ENVD1 and ENVD2. As environment function ENVD1 and ENVD2, for example, information of a navigation system, traffic information of a telematics system or the like can be used. Thus, for example, data on winding roads, inclines, protected areas with noise or speed limits, etc. can be made available. This information applies to a current driving situation.

The classifier 1 determines now by means of a predetermined optimization algorithm, for example, using a fuzzy method, which optimization criterion is to be used. In 1 For reasons of clarity, two optimal operating strategies are the optimization criteria 2a . 2 B shown. The first optimal operating strategy 2a applies if, in addition to the classic parameters setpoint torque TQI_SP and engine speed N, the environmental data ENVD1 is available. The second optimal operating strategy 2 B applies to the same characteristics TQI_SP and N but has different environment data ENVD2. The classifier 1 decides on the basis of its algorithm which optimization criterion of the two possible operating strategies 2a . 2 B should be selected. For example, decides on the first optimal operating strategy 2a , then the setpoints for the individual control systems over the zu 2a associated map set determined and issued. For example, an air pressure setpoint MAP_SP and an air mass setpoint MAF_SP are applied to the control system 3 specified for exhaust control. At its output then a corresponding actuator is controlled.

Furthermore, the unit gives 2a for a tax system 4 to control the fuel hydraulic (pressure pump) before a fuel pressure setpoint FUP_SP, which is also processed accordingly.

For controlling the injection system 5 , For example, the magnetic or piezoelectric actuator of an injector, the injection start SOI_SP and the injection quantity MF_x_SP of the fuel are specified. These values are also in the injection system 5 processed and passed a corresponding information to the actuator (actuator).

For the second optimal operating strategy 2 B the determination of the setpoint values takes place in the same way as for 2 B associated characteristic field set, so that the affected tax systems 3 . 4 . 5 correspondingly receive other parameter setpoints.

The two operating strategies 2a . 2 B for the local optimization are shown only as examples and can be extended arbitrarily.

2 shows a schematic representation of a device according to the invention, with which the operation of the internal combustion engine can be optimized. It essentially has a programmable control device 29 which reads in the various parameters and environmental data. For example, by an accelerator pedal 30 the setpoint for the driver's desired torque TQI_SP specified. The vehicle-internal sensors 31 provide additional data such as the engine speed N, the vehicle speed VS, the air pressure AMP, the ambient temperature TIA, etc. About the unit 32 For example, a navigation or telematics system, supplementary data, such as the vehicle weight VM, road characteristics ROAD, Verkehrsin formations TRAFIC and so on.

These input data for the above-mentioned optimization method represent the current operating and driving situation. On the basis of this data, the classifier decides 1 which optimization criterion should be selected. In 2 For example, the following optimization criteria were listed: the minimization of fuel consumption 33 , Minimizing NOx emission 34 , Minimization of particle emission 35 or minimizing noise emission 36 ,

Depending on which of the optimization criteria OPT1, OPT2, OPT3, OPT4 from the classifier 1 is selected at pre-controller level 38 determined from the associated map set the corresponding setpoints for the various control variables.

For completeness, it should be mentioned that the control device 29 an emergency function 37 (Limp Home Function), which is used to reset the classifier 1 can be achieved.

The setpoint values of the control variables determined in accordance with the optimization strategy become - as already the case 1 - to the appropriate tax systems 3 . 4 . 5 or the associated control algorithms. The control systems 3 . 4 . 5 then control their associated actuators 40 ,

On the basis of the block diagram of 3 is the optimization algorithm in the classifier below 1 explained in more detail. The classifier 1 preferably works according to the rules of fuzzy logic. It is believed that the unit 46 all data includes which of the units 30 . 31 , and 32 (see description to 2 ) and this to the classifier 1 supplies. These data are from a fuzzifier 22 mapped to a limited number of fuzzy sets. As an example, the input variable "road type" of a navigation system, which depending on the version, for example 16 discrete values can be mapped onto three fuzzy sets "subordinate roads", "middle roads" and "expressways". Furthermore contains the classifier 1 a rule base 21 which describes the required links of the input variables (fuzzy sets). A possible fuzzy rule would be, for example, "IF there is a subordinate road AND the vehicle is located in the city THEN minimize particulate emissions". Together with the algorithms of decision logic 23 Then, the memberships for a limited number of output quantities are determined from the multiplicity of input quantities, which describe the possible optimization criteria as well as a prioritization. A defuzzifier 24 converts the result from the fuzzy area into a concrete value of an output variable, eg an integer. This corresponds in each case to a specific optimization criterion or operating strategy. Im in 2 As shown, these would be the 4 criteria "Consumption Minimization", "NOx Minimization", "Particle Minimization" and "Noise Minimization". Further possible optimization criteria would be, for example, "driveability optimization" and "optimization of the particle filter regeneration mode" in diesel engines. The output value of the classifier then becomes, possibly together with additional values, for further processing in unit 25 made available.

4 shows in simplified representation a block diagram of the device for optimizing the operation of the internal combustion engine. The device shows the programmable controller 29 , which first the classifier 1 contains. Furthermore, it has a memory 43 for the optimization algorithm, a data store 44 for the map situation dependent on the driving situation and / or environmental conditions and a memory 45 for the classic control algorithms. Preferably, the control device 29 via a suitable data and control bus with one unit 46 (Sensor system), which at least the in-vehicle sensors (units 30 . 31 ), ideally also a navigation or telematics system (unit 32 ). All of these sensors and information units are arranged in the region of the vehicle. The internal combustion engine 41 is designed as a gasoline, diesel or gas engine with a direct injection system. It has at least one injector 47 so on the internal combustion engine 41 It is arranged that he puts the fuel into a cylinder 48 can inject. The injector 47 is via the control device 29 activated for fuel injection.

5 shows an example of possible changes in the optimization strategy over the European driving cycle. The lower diagram shows the predefined speed profile of the drive cycle, ie the vehicle speed v was plotted over time t. The upper diagram shows the currently selected optimization strategy OPT, for which four options were specified. This means optimization strategy 1 Consumption minimization, optimization strategy 2 "NOx minimization", optimization strategy 3 Particle Minimization and Optimization Strategy 4 ' Noise minimization " 5 shows, in the first part of the cycle, which is representative of city traffic, the optimization strategy is given priority 4 (at very low speeds or stationary vehicle) and the optimization strategies 2 and 3 (at medium speeds). in the extra-urban part of the cycle, especially at higher speeds, then outweighs optimization strategy 1 , By including the integral values of the exhaust emissions in the selection of the optimization strategy, it is ensured that the overall emission behavior improves over the drive cycle.

6 shows simulation results for the European driving cycle. The triangles show the integral NOx and particulate emission values PE for a 4-cylinder common rail diesel engine with multiple injection using a fixed map set whose values have been optimized for each operating point of the engine as a compromise on multiple emissions and consumption values (standard calibration) , The three different results are due to minor modifications of the standard calibration.

The circles in the diagram of 6 show the for the same system lower particulate emissions PE and thus improved results when according to the invention during the driving cycle, the operating strategy OPT is handled flexibly and the current driving situation adapted choice is made. The focus of optimization in this case was on minimizing particulate emissions. However, another focus criterion could be chosen. As 6 shows, can be reduced by about 20% by means of this inventively proposed dynamic optimization, the particle emission in tel without, for example, increases the NOx emission. This is a big advantage, since today's vehicles could already meet the harsher conditions of the future Euro 5 stage without any intervention in the hardware.

Claims (10)

Method for optimizing the operation of an internal combustion engine ( 41 ), which is designed with a fuel direct injection system, wherein for the optimization of the operation of several criteria, in particular with regard to the emission behavior and comfort, are taken into account, characterized in that in advance for several optimization criteria specific map sets are stored, depending on the driving situation and / or environmental conditions are assigned optimal operating values and that a classifier ( 1 ), which selects an optimization criterion for a current driving situation or environmental condition and then controls the direct fuel injection system or an affected other control system accordingly. Method according to claim 1, characterized in that that the optimization criteria are subdivided into subcriteria and that for each subcriterion a separate map set with optimal operating values is determined. A method according to claim 1 or 2, characterized in that as partial criteria of the NO _x emissions, the particle emission, driveability, the regeneration mode, the fuel consumption or the noise emission is used. Method according to one of the preceding claims, characterized in that the classifier ( 1 ) also uses information of a driver type recognition for further subdivision of the criterion driveability in addition to the environmental conditions. Method according to one of the preceding claims, characterized in that the classifier ( 1 ) Informa tion of sensors ( 46 ), which in the area of the internal combustion engine ( 41 ) are arranged. Method according to one of the preceding claims, characterized in that the classifier ( 1 ) Uses information from one or more information systems of the motor vehicle, in particular a navigation system, a radio-based telematics system or the like. Method according to one of the preceding claims, characterized in that the classifier ( 1 ) determines the optimization criterion with the aid of the fuzzy method. Method according to claim 7, characterized in that that with the help of the fuzzy method one of the following optimization criteria is selected: Optimization of exhaust emission, minimum fuel consumption, optimal Ride comfort, minimal noise emission or optimization of the regeneration mode of a particulate filter. Device for controlling a direct fuel injection system of an internal combustion engine, having a programmable control device ( 29 ), which is a data store ( 44 ) and an algorithm for determining an optimization criterion, with which the direct fuel injection system or another control system of the vehicle is controllable, characterized in that the control device ( 29 ) is designed to determine in advance for several optimization criteria of the driving situation and / or environmental conditions dependent map sets and in the data memory ( 44 ) and that the control device ( 29 ) a classifier ( 1 ), which depends on a current driving situation and / or environmental condition from the data memory ( 44 ) an optimization criterion preferably with respect to the emission of the exhaust gas, a minimum fuel consumption, optimum ride comfort, minimum noise emission or regeneration of the particulate filter. Apparatus according to claim 9, characterized in that the direct fuel injection system for a gasoline, diesel or gas engine ( 21 ) is trained.