JP4258572B2 - Internal combustion engine control device and fuel property detection device - Google Patents

Description

  The present invention relates to an internal combustion engine control device and a fuel property detection device.

  Conventionally, not only gasoline but also an internal combustion engine that can use various fuels such as an alcohol-mixed liquid fuel obtained by mixing alcohol with gasoline is known. However, the properties of gasoline and alcohol-mixed fuel are different, and the alcohol concentration or the component ratio in the alcohol-mixed fuel is not always constant, so that the fuel property may be different every time the engine is refueled.

  On the other hand, when the fuel property changes, for example, the theoretical air-fuel ratio changes. Therefore, when the fuel injection amount is controlled so that the air-fuel ratio matches the target air-fuel ratio with the feedback correction coefficient based on the output of the air-fuel ratio sensor arranged in the exhaust passage, the fuel property is the feedback correction coefficient. It will be represented by the average value. Therefore, an internal combustion engine is known in which the fuel property is obtained from the average value of the feedback correction coefficient, and the engine is controlled according to the fuel property (see Patent Document 1).

JP 2006-77683 A

  In the internal combustion engine described above, when the property of the fuel in the fuel tank changes due to refueling, the feedback correction coefficient gradually changes and stabilizes at a value determined according to the fuel property. For this reason, when the property of the fuel supplied to the engine has changed significantly due to refueling, it takes a long time for the feedback correction coefficient to stabilize. However, the fuel properties are not accurately determined until the feedback correction coefficient is stabilized, and therefore, good engine control based on the fuel properties is performed for a while after the engine operation is resumed after refueling. There is a problem that it cannot be done.

  In order to solve the above problems, according to the present invention, the fuel tank is provided with a fuel chamber and a residual fuel chamber that can communicate with each other or shut off, and when fueling is performed, the fuel chamber and the residual fuel chamber that have been communicated with each other are provided. When the engine operation is resumed after refueling, the fuel supply chamber and the remaining fuel chamber are shut off from each other, and only the fuel in the remaining fuel chamber is supplied to the engine. In addition, engine control is performed in accordance with the predetermined properties of the fuel in the remaining fuel chamber, and when a predetermined condition is satisfied, the fuel in the fuel chamber and the remaining fuel chamber are kept shut off from each other. And the fuel in the remaining fuel chamber are supplied to the engine at a predetermined rate, and the fuel supplied to the engine at the predetermined rate based on the engine state quantity obtained at this time Obtain the properties, obtain the average properties of the fuel in the refueling chamber and the fuel in the remaining fuel chamber based on the properties of the fuel supplied to the engine at the predetermined ratio and the properties of the remaining fuel determined in advance. The fueling chamber and the remaining fuel chamber are connected to each other so that the fuel in the fueling chamber and the fuel in the remaining fuel chamber are mixed with each other, and the fuel is supplied to the engine from at least one of the fueling chamber and the remaining fuel chamber. The engine is controlled according to the average fuel property.

  In order to solve the above problems, according to the present invention, a reference fuel chamber containing a reference fuel whose properties are known in advance and a target fuel chamber containing a target fuel whose properties are unknown are provided. The fuel and the target fuel are supplied to the engine at a predetermined ratio, and the properties of the target fuel or the fuel in the reference fuel chamber and the fuel in the target fuel chamber are determined based on the engine state quantity and the reference fuel properties obtained at this time. The average property is calculated.

  Good engine control based on fuel properties can be secured when engine operation is resumed after refueling.

  FIG. 1 shows a case where the present invention is applied to a spark ignition type internal combustion engine. However, the present invention can also be applied to a compression ignition type internal combustion engine.

  Referring to FIG. 1, for example, 1 is an engine body having four cylinders, 2 is a cylinder block, 3 is a cylinder head, 4 is a piston, 5 is a combustion chamber, 6 is an intake valve, 7 is an intake port, and 8 is an exhaust. A valve, 9 is an exhaust port, and 10 is a spark plug. The intake port 7 is connected to a surge tank 12 via a corresponding intake branch pipe 11, and the surge tank 12 is connected to an air cleaner 14 via an intake duct 13. An air flow meter 15 for detecting the intake air mass flow rate Ga and a throttle valve 17 driven by a step motor 16 are arranged in the intake duct 13. In addition, an electrically controlled fuel injection valve 18c that directly injects fuel into the combustion chamber 5 is disposed in the combustion chamber 5 of each cylinder. Hereinafter, the fuel injection valve 18c is referred to as an in-cylinder injection valve.

  The fuel tank 19 is provided with an oil supply chamber 19f and a residual fuel chamber 19r separated from each other by a partition wall 19w in the internal space. A communication hole is formed in the partition wall 19w, and an electromagnetic shut-off valve 20 is disposed in the communication hole. Therefore, when the shutoff valve 20 is opened, the fuel supply chamber 19f and the remaining fuel chamber 19r communicate with each other, and the fuel in the fuel supply chamber 19f and the fuel in the remaining fuel chamber 19r are mixed with each other. On the other hand, when the shutoff valve 20 is closed, the fuel supply chamber 19f and the remaining fuel chamber 19r are shut off from each other. The fuel supply chamber 19f is provided with a fuel supply port 19i. However, the remaining fuel chamber 19r is not provided with a fuel supply port. The lid 21 of the filler port 19i is attached with a filler port sensor 22 that emits a signal indicating that the filler port 19i is opened and fueling is performed.

  Fuel supply branch pipes 23f and 23r are connected to the fuel supply chamber 19f and the remaining fuel chamber 19r, respectively. These fuel supply branch pipes 23f and 23r are connected to a fuel supply pipe 25 via a common metering device 24. The fuel supply pipe 25 is connected to each in-cylinder injection valve 18c via a fuel pressure accumulation chamber, that is, a delivery pipe 26c. Electronically controlled fuel pumps 27f and 27r with variable discharge amount are disposed in the fuel supply branch pipes 23f and 23r, respectively. In the example shown in FIG. 1, these fuel pumps 27f and 27r are accommodated in the fuel supply chamber 19f and the remaining fuel chamber 19r, respectively, but may be disposed outside the fuel supply chamber 19f and the remaining fuel chamber 19r. When the fuel pumps 27f and 27r disposed in the fueling chamber 19f and the remaining fuel chamber 19r are referred to as a fueling chamber pump and a remaining fuel chamber pump, respectively, the fuel in the fueling chamber 19f and the fuel in the remaining fuel chamber 19r are refueled. The fuel is supplied to the metering device 24 by the chamber pump 27f and the residual fuel chamber pump 27r, and is supplied to the in-cylinder injection valve 18c through the fuel supply pipe 25 and the delivery pipe 26c. A fuel amount sensor for detecting the fuel amount QFf in the fuel chamber 19f and the fuel amount QFr in the remaining fuel chamber 19r is attached to the fuel chamber pump 27f and the remaining fuel chamber pump 27r, respectively. In the present invention, for example, a fuel property sensor for detecting the property of the fuel flowing through the fuel supply pipe 25 is not provided in the fuel supply pipe 25.

  The metering device 24 is for supplying the fuel in the fuel supply chamber 19f and the fuel in the remaining fuel chamber 19r to the fuel supply pipe 25 at a predetermined ratio. That is, in the metering device 24, the ratio of the fuel amount in the fuel supply chamber 19f out of the fuel supplied to the engine via the in-cylinder injection valve 18c when both the fuel supply chamber pump 27f and the remaining fuel chamber pump 27r are operated. q (0 <q <1), and the ratio of the fuel amount in the remaining fuel chamber 19r is set to (1-q). Naturally, when only the fuel chamber pump 27f is operated, only the fuel in the fuel chamber 19f is supplied from the metering device 24 to the in-cylinder injection valve 18c, and when only the residual fuel chamber pump 27r is operated, the remaining fuel chamber. Only the fuel in 19r is supplied from the metering device 24 to the in-cylinder injection valve 18c.

  During normal operation other than immediately after refueling, the shutoff valve 20 is opened, the refueling chamber pump 27f is operated, and the remaining fuel chamber pump 27r is stopped. Therefore, during normal operation, the fuel in the fueling chamber 19f and the remaining fuel chamber 19r is supplied to the cylinder injection valve 18c by the fueling chamber pump 27f and supplied to the engine. During normal operation, only the remaining fuel chamber pump 27r may be operated, or both the fueling chamber pump 27f and the remaining fuel chamber pump 27r may be operated.

  In the internal combustion engine of FIG. 1, fossil liquid fuels such as gasoline and light oil, liquid alcohol, or a mixture thereof can be used as fuel. In this case, the fuel properties can be expressed by, for example, the ratio or concentration of a specific component, viscosity, evaporation characteristics, average molecular weight, and the like.

  On the other hand, the exhaust port 9 is connected to a small capacity auxiliary catalyst 31 via an exhaust manifold 30, and the auxiliary catalyst 31 is connected to a large capacity main catalyst 33 via an exhaust pipe 32. An air-fuel ratio sensor 34 for detecting the air-fuel ratio is attached to the exhaust pipe 32.

  The electronic control unit 40 is composed of a digital computer, and is connected to each other by a bidirectional bus 41. A ROM (read only memory) 42, a RAM (random access memory) 43, a CPU (microprocessor) 44, an input port 45 and an output port 46 It comprises. A water temperature sensor 35 for detecting the engine cooling water temperature is attached to the engine body 1. Further, a load sensor 50 for detecting the depression amount of the accelerator pedal 49 is connected to the accelerator pedal 49. Here, the depression amount of the accelerator pedal 49 represents a required load. The output signals of the air flow meter 15, the fuel inlet sensor 22, the fuel amount sensors of the fuel chamber pump 27f and the remaining fuel chamber pump 27r, the air-fuel ratio sensor 34, the water temperature sensor 35, and the load sensor 50 are respectively sent through corresponding AD converters 47. To the input port 45. Further, the input port 45 includes a crank angle sensor 51 that generates an output pulse every time the crankshaft rotates, for example, 30 °, and an ignition (IG) switch 52 that generates an output pulse indicating whether the crankshaft is on or off. Connected. The CPU 44 calculates the engine speed Ne based on the output pulse of the crank angle sensor 51. On the other hand, the output port 46 is connected to the spark plug 10, the step motor 16, the in-cylinder injection valve 18c, the shutoff valve 20, the fuel supply chamber pump 27f, and the remaining fuel chamber pump 27r through corresponding drive circuits 48, respectively. Control is performed based on an output signal from the control unit 40. In the embodiment according to the present invention, electric power is supplied to the electronic control unit 40 even when the ignition switch 52 is turned off.

  In the internal combustion engine of FIG. 1, the fuel injection time TAU is calculated based on the following equation (1).

TAU = TB · (1 + FAF + kI + kF) (1)
Here, TB represents a basic fuel injection time, FAF represents a feedback correction coefficient, kI represents an increase correction coefficient, and kF represents a property correction coefficient.

  When the fuel whose properties are basic properties is referred to as basic fuel, the basic fuel injection time TB is the fuel injection time required to set the air-fuel ratio to the target air-fuel ratio when the fuel supplied to the engine is the basic fuel. And stored in advance in the ROM 42 as a function of the engine operating state, for example, the output of the air flow meter 15 and the engine speed.

  The feedback correction coefficient FAF is used to make the actual air-fuel ratio coincide with the target air-fuel ratio, and is calculated based on the air-fuel ratio detected by the air-fuel ratio sensor 34. This feedback correction coefficient FAF fluctuates around zero, and is maintained at zero when correction is not necessary.

  The increase correction coefficient kI is a collective representation of the start-up increase correction coefficient, the acceleration increase correction coefficient, and the like, and is maintained at zero when correction is not necessary.

  The property correction coefficient kF is determined according to the property of the fuel supplied to the engine, and is maintained at zero when the fuel supplied to the engine is a basic fuel.

  First, a method for calculating the feedback correction coefficient FAF will be briefly described with reference to FIGS. In the embodiment according to the present invention, the target air-fuel ratio is set to the stoichiometric air-fuel ratio, and in this case, an oxygen concentration sensor that detects the oxygen concentration in the exhaust gas is used as the air-fuel ratio sensor 34. The output voltage V of the oxygen concentration sensor 34 is substantially the reference voltage VR when the air-fuel ratio is the stoichiometric air-fuel ratio, and is approximately 1.0 (volt) when the air-fuel ratio is richer than the stoichiometric air-fuel ratio. When it is leaner than the air-fuel ratio, it becomes almost 0 (volt).

  FIG. 4 shows a routine for calculating the feedback correction coefficient FAF. Referring to FIG. 4, in step 100, it is determined whether or not a condition for executing feedback control is satisfied. In the embodiment according to the present invention, it is determined that the feedback control execution condition is satisfied when the oxygen concentration sensor 34 is activated and the engine warm-up operation is completed, and it is determined that the other conditions are not satisfied. The When it is determined that the feedback control execution condition is not satisfied, the routine proceeds to step 101 where the feedback correction coefficient FAF is fixed to zero. On the other hand, when it is determined that the feedback control execution condition is satisfied, the routine proceeds to step 102 where it is determined whether or not the output voltage V of the oxygen concentration sensor 34 is higher than the reference voltage VR. Next, when V> VR, the routine proceeds to step 103, where it is determined whether or not the output voltage VP of the oxygen concentration sensor 34 in the previous processing cycle is equal to or lower than the reference voltage VR. When VP ≦ VR, that is, when the air-fuel ratio is switched from lean to rich with respect to the stoichiometric air-fuel ratio, the routine proceeds to step 104 where the skip value SR is subtracted from the feedback correction coefficient FAF. As a result, the feedback correction coefficient FAF is greatly reduced as shown in FIG. Next, the routine proceeds to step 109. On the other hand, when VP> VR, that is, when the air-fuel ratio continues and is rich with respect to the stoichiometric air-fuel ratio, the routine proceeds to step 105 where the integral value IR (<< SR) is subtracted from the feedback correction coefficient FAF. As a result, the feedback correction coefficient FAF gradually decreases as shown in FIG. Next, the routine proceeds to step 109. On the other hand, when V ≦ VR in step 102, the routine proceeds to step 106, where it is determined whether or not the output voltage VP of the oxygen concentration sensor 34 in the previous processing cycle is higher than the reference voltage VR. When VP> VR, that is, when the air-fuel ratio is switched from rich to lean with respect to the stoichiometric air-fuel ratio, the routine proceeds to step 107 where the skip correction value SL is added to the feedback correction coefficient FAF. As a result, the feedback correction coefficient FAF significantly increases as shown in FIG. Next, the routine proceeds to step 109. On the other hand, when VP ≦ VR, that is, when the air-fuel ratio continues to be lean with respect to the stoichiometric air-fuel ratio, the routine proceeds to step 108 where the integral value IL (<< SL) is added to the feedback correction coefficient FAF. As a result, the feedback correction coefficient FAF gradually increases as shown in FIG. Next, the routine proceeds to step 109. In step 109, the output voltage V of the oxygen concentration sensor 34 in the current processing cycle is stored as VP.

  By the way, when the feedback correction coefficient FAF is stable, that is, when the air-fuel ratio is substantially maintained at the stoichiometric air-fuel ratio, the average value or fluctuation center of the feedback correction coefficient FAF is determined according to the theoretical air-fuel ratio. The air-fuel ratio is determined according to the properties of the fuel supplied to the engine. Therefore, when the property of the fuel supplied to the engine is changed, the feedback correction coefficient average value FAFA changes, and the changed feedback correction coefficient average value FAFA is the property of the fuel supplied to the engine, more precisely, the basic property. Represents the deviation from. The change amount of the feedback correction coefficient average value FAFA that occurs when the property of the fuel supplied to the engine is changed represents the change amount of the property of the fuel supplied to the engine.

  Then, when the feedback correction coefficient average value FAFA changes, the new property correction coefficient kF is newly supplied to the engine by adding the change amount of the feedback correction coefficient average value FAFA to the previous property correction coefficient kF. Will be accurately represented. At the same time, when subtracted from the feedback correction coefficient FAF by the amount added to the property correction coefficient kF, the fuel injection time TAU can be maintained as can be seen from the above equation (1).

  That is, in the example shown in FIG. 5, when the property of the fuel supplied to the engine is changed at the time X, the feedback correction coefficient FAF increases by the integral value IL described above. Next, as indicated by Y in FIG. 5, the feedback correction coefficient FAF is stabilized and the air-fuel ratio is maintained substantially at the stoichiometric air-fuel ratio. As a result, the average value of the feedback correction coefficient increases by ΔF from FAFA2 to FAFA1. In this case, as indicated by Z in FIG. 5, the property correction coefficient kF is increased by ΔF, and the feedback correction coefficient FAF is decreased by ΔF. The same applies to the case where the feedback correction coefficient FAF decreases when the property of the fuel supplied to the engine is changed.

  In this way, even if the fuel having a property different from the property of the fuel remaining in the fuel tank 19 is supplied and the property of the fuel supplied to the engine is changed, the property correction coefficient kF is the value of the fuel supplied to the engine. The properties are accurately represented, and the air-fuel ratio can be reliably maintained at the stoichiometric air-fuel ratio by controlling the air-fuel ratio using the property correction coefficient kF.

  The nature of the fuel supplied to the engine is determined not only by the feedback correction coefficient average value FAFA, but also by the engine state quantity such as the optimum ignition timing such as MBT, knock limit, combustion pressure, timing when the combustion pressure peaks, and idling speed. Is also represented. Therefore, the property correction coefficient kF may be calculated based on the optimal ignition timing or the like. Therefore, in general terms, the properties of the fuel supplied to the engine are determined based on the engine state quantity obtained at this time.

  However, as can be seen from FIG. 5, when fueling is performed and the fuel properties are changed, the feedback correction coefficient FAF is changed little by little with the small integral values IR and IL (see FIG. 3). Therefore, in particular, when the fuel property changes significantly, it takes a long time to calculate the property correction coefficient kF representing the property of the fuel supplied to the engine after refueling until the feedback correction coefficient FAF is stabilized. .

  Therefore, in the embodiment according to the present invention, when refueling is performed, the following pre-refueling process and post-refueling process are performed. Next, the pre-oiling process and the post-oiling process will be described with reference to FIG.

  Referring to FIG. 6, at the time of normal operation not immediately after refueling, as described above, the shutoff valve 20 is opened and only the refueling chamber pump 27f is operated. Next, as shown by t1 in FIG. 6, when the ignition switch 52 is turned off to stop the engine operation, the operation of the oil supply chamber pump 27f is stopped. Next, when the fuel filler opening 19i is opened to perform refueling, the shutoff valve 20 is closed as indicated by t2 in FIG. 6, so that the fuel fill chamber 19f and the remaining fuel chamber 19f of the fuel tank 19 are shut off from each other. Next, new fuel is supplied from the fuel supply port 19i only to the fuel supply chamber 19f. In this case, new fuel does not flow into the remaining fuel chamber 19r, and the properties of the fuel in the remaining fuel chamber 19r are maintained at the properties of the fuel supplied to the engine before refueling. On the other hand, the fuel in the refueling chamber 19f after refueling is composed of a mixture of the fuel remaining before refueling and the newly refueled fuel.

  After refueling is completed, when the ignition switch 52 is turned on and the engine operation is restarted as indicated by t3 in FIG. 6, only the remaining fuel chamber pump 27f is operated with the shutoff valve 20 closed. As a result, only the fuel in the remaining fuel chamber 19r is supplied to the engine. If the property correction coefficient kF representing the property of the fuel in the remaining fuel chamber 19r at this time is represented by kFr, the property correction coefficient kFr has already been calculated before refueling. Therefore, at this time, by setting the property correction coefficient kF to kFr and performing the engine operation, the engine control according to the property of the fuel supplied to the engine can be performed accurately.

  Next, when a predetermined calculation condition is satisfied, as shown by t4 in FIG. 6, both the fuel chamber pump 27f and the remaining fuel chamber pump 27r are operated with the shutoff valve 20 closed, and the fuel in the fuel chamber 19f A property correction coefficient kFa representing the average property of the fuel in the remaining fuel chamber 19r is calculated. Here, the average property of the fuel in the fuel supply chamber 19f and the fuel in the remaining fuel chamber 19r means the average property of the fuel in the fuel tank 19 when the shutoff valve 20 is opened.

  Next, when the calculation of the property correction coefficient kFa is completed, the shutoff valve 20 is opened as shown by t5 in FIG. 6, only the oil supply chamber pump 27f is operated, and the normal operation is performed with the property correction coefficient kF set to this kFa. Is resumed. As a result, it is possible to accurately perform engine control in accordance with the properties of the fuel supplied to the engine during engine operation after refueling.

  Next, a method for calculating the property correction coefficient kFa will be described. As described above, the property correction coefficient kFa represents the average property of the fuel in the fuel supply chamber 19f and the fuel in the remaining fuel chamber 19r, and can be expressed by the following equation (2).

kFa = {QFf · kFf + QFr · kFr} / (QFf + QFr) (2)
Here, kFf represents a property correction coefficient representing the property of the fuel in the fuel supply chamber 19f when the shutoff valve 20 is closed after refueling.

  Therefore, if the property correction coefficient kFf for the fuel in the refueling chamber 19f is calculated and the fuel amount QFf in the refueling chamber 19f and the fuel amount QFr in the remaining fuel chamber 19r are detected by the fuel amount sensor, the property correction coefficient kFa is obtained. It can be calculated.

  On the other hand, when both the fuel chamber pump 27f and the remaining fuel chamber pump 27r are operated with the shutoff valve 20 closed, the fuel in the fuel chamber 19f and the remaining fuel chamber are measured by the metering device 24 (FIG. 1) as described above. Fuel in 19r is mixed at a ratio of q: (1-q) and supplied to the engine. In this case, if the property correction coefficient representing the property of the mixed fuel supplied to the engine is kFq, the property correction coefficient kFq is expressed by the following equation.

kFq = q.kFf + (1-q) .kFr
Therefore, the property correction coefficient kFf is expressed by the following equation (3).

kFf = {kFq− (1-q) · kFr} / q (3)
Therefore, in the embodiment according to the present invention, when the property correction coefficient kFa is to be calculated (t4 in FIG. 6), first, both the oil supply chamber pump 27f and the remaining fuel chamber pump 27r are operated while the shutoff valve 20 is closed. The property correction coefficient kFq is calculated from the change amount of the average value FAFA of the obtained feedback correction coefficients FAF, then the property correction coefficient kFf is calculated from the equation (3), and then the property correction coefficient kFa is calculated from the equation (2). I have to.

  In this regard, in the embodiment according to the present invention, the fuel in the remaining fuel chamber 19r whose properties are known in advance and the fuel in the fuel supply chamber 19f whose properties are unknown are supplied to the engine at a predetermined ratio. Based on the obtained engine state quantity and the fuel property (kFr) in the remaining fuel chamber 19r, the fuel property (kFf) in the fuel chamber 19f or the fuel in the fuel chamber 19f and the fuel in the remaining fuel chamber 19r It can also be said that the average property (kFa) is obtained.

  The calculation of the property correction coefficient kFa is started when the above-described calculation condition is satisfied (t4 in FIG. 6). In the embodiment according to the present invention, kFq is calculated in order to calculate the property correction coefficient kFa, and the feedback control execution condition needs to be satisfied in order to calculate kFq. Therefore, in the embodiment according to the present invention, it is determined that the above-described calculation condition is not satisfied until the feedback control execution condition is satisfied, and it is determined that the calculation condition is satisfied when the feedback control execution condition is satisfied.

  When the calculation of the property correction coefficient kFa is started, a ratio of the fuel supplied to the engine from the fuel in the remaining fuel chamber 19r to the fuel in the fuel chamber 19f and the fuel in the remaining fuel chamber 19r (q : (1-q)). In this case, until the feedback correction coefficient FAF deviates from zero and stabilizes, that is, until the calculation of the property correction coefficient kFq is completed, it is not necessarily the case that the engine control according to the property of the fuel supplied to the engine is performed. Needless to say, the time required for calculating the property correction coefficient kFq or kFa is preferably as short as possible. From this point, it is preferable to set the ratio q of the fuel in the fuel supply chamber 19f to a value as small as possible and to a value smaller than 0.5 at most.

  On the other hand, when the property correction coefficient kFq or kFa is to be calculated, the fuel in the refueling chamber 19f and the fuel in the remaining fuel chamber 19r are converted into the fuel amount QFf in the refueling chamber 19f and the fuel amount QFr in the remaining fuel chamber 19r. When supplied at a ratio (QFf / (QFf + QFr): QFr / (QFf + QFr)) that matches the ratio, the property correction coefficient kFq calculated at this time is the fuel in the fuel tank 19 when the shutoff valve 20 is opened. Therefore, kFa can be directly and easily calculated.

  FIG. 7 shows a replenishment pretreatment routine according to an embodiment of the present invention. This routine is executed by interruption every predetermined time.

  Referring to FIG. 7, first, at step 120, it is judged if the fuel filler opening 19i of the fuel tank 19 is opened. When the refueling port 19i is not opened, that is, when refueling is not performed, the processing cycle is ended. When the refueling port 19i is opened, that is, when refueling is performed, the process proceeds to step 121, and the shutoff valve 20 is closed. Is done. In subsequent step 122, the property correction coefficient kF at this time is stored as kFr. In the following step 123, the calculation flag is reset. This calculation flag is reset when refueling is performed, and then set when the calculation of the property correction coefficient kFa is completed.

  FIG. 8 shows an after-oiling processing routine of the embodiment according to the present invention. This routine is executed by interruption every predetermined time.

  Referring to FIG. 8, first, at step 140, it is judged if the calculation flag is reset. Since the calculation flag is reset when the engine operation is resumed after refueling, the routine proceeds to step 141 where it is determined whether or not the feedback control execution condition is satisfied. When the feedback control execution condition is not satisfied, the routine proceeds to step 142 where the fuel chamber pump 27f is stopped and the remaining fuel chamber pump 27r is operated. In subsequent step 143, the property correction coefficient kF is set to the property correction coefficient kFr for the fuel in the remaining fuel chamber 19r.

  Next, when the feedback control execution condition is satisfied, the routine proceeds from step 141 to step 144, where the fueling chamber pump 27f and the remaining fuel chamber pump 27r are operated. In the following step 145, a routine for calculating the property correction coefficient kFa is executed. A routine for calculating the property correction coefficient kFa is shown in FIG.

  Referring to FIG. 9, first, at step 160, it is judged if the feedback correction coefficient FAF has become stable. As long as the feedback correction coefficient FAF is not stabilized, the processing cycle is terminated. When the feedback correction coefficient FAF is stabilized, the process proceeds to step 161, and the average value or the fluctuation center FAFA of the feedback correction coefficient FAF at this time is calculated. In the following step 162, only the feedback correction coefficient average value FAFA is added to the property correction coefficient kF, and only FAFA is subtracted from the feedback correction coefficient FAF. In the following step 163, the property correction coefficient kFf for the fuel in the fuel supply chamber 19f is calculated from the above equation (3). In the following step 164, the property correction coefficient kFa for the fuel mixture in the fuel supply chamber 19f and the fuel in the remaining fuel chamber 19r is calculated from the above equation (2). In the following step 165, the calculation flag is set.

  Referring again to FIG. 8, when the calculation flag is set, the routine proceeds from step 140 to step 146, where the shutoff valve 20 is opened. In the following step 147, the fuel chamber pump 27f is operated and the remaining fuel chamber pump 27r is stopped. In the following step 148, the property correction coefficient kF is set to kFa calculated by the routine of FIG.

  FIG. 10 shows a routine for calculating the fuel injection time TAU. This routine is executed by interruption every predetermined crank angle.

  Referring to FIG. 10, first, at step 180, the basic fuel injection time TB is calculated, and at step 181 the increase correction coefficient kI is calculated. In the subsequent step 182, the routine for calculating the feedback correction coefficient FAF shown in FIG. 4 is executed, and in the subsequent step 183, the property correction coefficient kF set in the post-fuel supply processing routine in FIG. 8 is read. In the following step 184, the fuel injection time TAU is calculated from the equation (1). Fuel is injected from the in-cylinder injection valve 18c by TAU.

  As can be seen from the routine of FIG. 8, the property correction coefficient kFa is immediately calculated when the feedback control execution condition is satisfied when engine operation is resumed after refueling. That is, when the engine operation is resumed, it is not necessary to supply only the fuel in the remaining fuel chamber 19r to the engine.

  Further, after the property correction coefficient kFq is calculated, the fuel in the fuel supply chamber 19f and the fuel in the remaining fuel chamber 19r are determined in a predetermined ratio (q: (1-q) while the shutoff valve 20 is closed. ) And the property correction coefficient kF can be set to this kFq to perform engine control. Alternatively, after the property correction coefficient kFf is calculated, only the fuel in the fuel supply chamber 19f is supplied to the engine while the shutoff valve 20 is closed, and the property correction coefficient kF is set to this kFf to control the engine. You can also do it.

  The internal combustion engine shown in FIG. 1 has only one fuel injection valve, and this single fuel injection valve is composed of an in-cylinder injection valve 18c. However, only one fuel injection valve can be constituted by a port injection valve which is a fuel injection valve for injecting fuel into the intake passage. However, part of the fuel injected from the port injection valve once adheres to the inner wall surface of the intake port 7 and then evaporates and flows into the combustion chamber 5. On the other hand, the nature of the fuel in the oil supply chamber 19f immediately after refueling is not known. For this reason, when the evaporation characteristics of the fuel in the fuel supply chamber 19f and the evaporation characteristics of the fuel in the remaining fuel chamber 19r are significantly different, the fuel and the remaining fuel in the fuel supply chamber 19f are calculated in order to calculate the property correction coefficient kFq or kFa. When the fuel in the fuel chamber 19r is mixed at a predetermined ratio and injected from the port injection valve, the ratio of the fuel that flows into the combustion chamber 5 and burns is not maintained at the above-described predetermined ratio. The calculated kFq does not accurately represent the properties of the fuel in the fuel supply chamber 19f and the fuel in the remaining fuel chamber 19r mixed at a predetermined ratio. On the other hand, in the case of the in-cylinder injection valve, the fuel is directly injected into the combustion chamber 5, so that the ratio of the fuel burned in the combustion chamber 5 can be maintained at the above-described predetermined ratio. .

  That is, after the fuel supply is performed and until the calculation of the fuel property coefficient kFq or kFa is completed, the fuel in the fuel supply chamber 19f is prohibited from being injected from the port injection valve, and is injected from the in-cylinder injection valve 18c. This is preferable.

  In order to achieve this, when only one fuel injection valve is provided as in the internal combustion engine of FIG. 1, it is preferable that this single fuel injection valve is composed of the in-cylinder injection valve 18c. Become.

  On the other hand, FIG. 11 shows another embodiment according to the present invention having two fuel injection valves, that is, an in-cylinder injection valve 18c and a port injection valve 18p. In this example, the fuel supply pipe 25 extending from the metering device 24 is branched into a cylinder injection valve supply pipe 25c and a port injection valve supply pipe 25p, and the cylinder injection valve supply pipe 25c is used for the cylinder injection valve. The cylinder injection valve 18c is connected to each in-cylinder injection valve 18c via a delivery pipe 26c, and the port injection valve supply pipe 25p is connected to each port injection valve 18p via a port injection valve delivery pipe 26p. As a result, one or both of the fuel in the fuel supply chamber 19f and the fuel in the remaining fuel chamber 19r are supplied to the engine from the cylinder injection valve 18c, and the fuel and remaining fuel chamber in the fuel supply chamber 19f are also supplied from the port injection valve 18p. One or both of the fuels in 19r may be supplied to the engine.

  In the example shown in FIG. 11, when the property correction coefficient kFa is to be calculated, as shown by t4 in FIG. 12, the oil supply chamber pump 27f and the remaining fuel chamber pump 27r are operated, and only the in-cylinder injection valve 18c is operated. Therefore, the fuel in the refueling chamber 19f and the fuel in the remaining fuel chamber 19r are supplied from the in-cylinder injection valve 18c to the engine at a predetermined ratio (q: (1-q)). As a result, as described above, the ratio of the fuel burned in the combustion chamber 5 can be maintained at the above-described predetermined ratio.

  When engine operation is resumed after refueling, only the remaining fuel chamber pump 27r is operated and only the in-cylinder injection valve 18c is operated, as shown by t3 in FIG. Only the fuel in the remaining fuel chamber 19r is supplied to the engine only from 18c. As a result, fuel can be reliably supplied into the combustion chamber 5 when the engine is started. In this case, in order to supply the fuel in the remaining fuel chamber 19r to the engine, only the port injection valve 18p can be used, or both the in-cylinder injection valve 18c and the port injection valve 18p can be used. This is because the nature of the fuel in the remaining fuel chamber 19r is known, and thus it can be predicted how much the fuel adheres to the inner wall surface of the intake port 7 when injected from the port injection valve 18p.

  On the other hand, during normal operation, fuel is supplied to the engine from the in-cylinder injection valve 18c and the port injection valve 18p, for example, according to the engine operating state. For example, only the in-cylinder injection valve 18c is used to supply fuel to the engine during low engine load operation, and only the port injection valve 18p is used during high load operation. Alternatively, both the in-cylinder injection valve 18c and the port injection valve 18p can be used. In the example shown in FIG. 12, only the in-cylinder injection valve 18c is used for fuel supply during normal operation before refueling, and only the port injection valve 18p is used during normal operation after calculating the property correction coefficient kFa.

  FIG. 13 shows a refueling aftertreatment routine according to another embodiment of the present invention. This routine is executed by interruption every predetermined time.

  Referring to FIG. 13, first, at step 140, it is judged if the calculation flag is reset. Since the calculation flag is reset when the engine operation is resumed after refueling, the routine proceeds to step 141 where it is determined whether or not the feedback control execution condition is satisfied. When the feedback control execution condition is not satisfied, the routine proceeds to step 142 where the fuel chamber pump 27f is stopped and the remaining fuel chamber pump 27r is operated. In the subsequent step 142a, the cylinder injection valve 18c is operated while the operation of the port injection valve 18p is stopped. In this case, the fuel in the remaining fuel chamber 19r is injected from the in-cylinder injection valve 18c for the fuel injection time TAU. In subsequent step 143, the property correction coefficient kF is set to the property correction coefficient kFr for the fuel in the remaining fuel chamber 19r.

  Next, when the feedback control execution condition is satisfied, the routine proceeds from step 141 to step 144, where the fueling chamber pump 27f and the remaining fuel chamber pump 27r are operated. In the following step 144a, the cylinder injection valve 18c is operated while the operation of the port injection valve 18p is stopped. In this case, the fuel in the fuel supply chamber 19f and the fuel in the remaining fuel chamber 19r are injected from the in-cylinder injection valve 18c for a fuel injection time TAU at a predetermined ratio. In the subsequent step 145, a routine for calculating the property correction coefficient kFa shown in FIG. 9 is executed.

  When the calculation flag is set in the routine for calculating the property correction coefficient kFa, the routine proceeds from step 140 to step 146, where the shutoff valve 20 is opened. In the following step 147a, the fuel supply chamber pump 27f, the remaining fuel chamber pump 27r, the cylinder injection valve 18c, and the port injection valve 18p are normally controlled. In the following step 148, the property correction coefficient kF is set to kFa calculated by the routine of FIG.

  Other configurations and operations of the embodiment shown in FIG. 11 are the same as those of the embodiment shown in FIG.

  FIG. 14 shows a modification of another embodiment according to the present invention shown in FIG. In the example shown in FIG. 14, the fuel supply branch pipe 23f connected to the fuel supply chamber 19f is branched into a cylinder injection valve supply pipe 25c and a port injection valve supply pipe 25p, and the cylinder injection valve supply pipe 25c. Is connected to each in-cylinder injection valve 18c via an in-cylinder injection valve delivery pipe 26c, and the port injection valve supply pipe 25p is connected to each port injection valve 18p via a port injection valve delivery pipe 26p. Further, the fuel supply branch pipe 23r connected to the remaining fuel chamber 19r is connected to the in-cylinder injection valve supply pipe 25c without being connected to the port injection valve supply pipe 25p. As a result, in this case, one or both of the fuel in the fuel supply chamber 19f and the fuel in the remaining fuel chamber 19r are supplied to the engine from the cylinder injection valve 18c, and the fuel in the fuel supply chamber 19f is supplied from the port injection valve 18p. Only fuel can be supplied to the engine.

  In the example shown in FIG. 14, as in the example shown in FIG. 11, when the engine operation is resumed after refueling, only the remaining fuel chamber pump 27r is operated, as indicated by t3 in FIG. Only the in-cylinder injection valve 18c is operated, so that only the fuel in the remaining fuel chamber 19r is supplied from the in-cylinder injection valve 18c to the engine. As a result, fuel can be reliably supplied into the combustion chamber 5 when the engine is started.

  Next, when the property correction coefficient kFa is to be calculated, as indicated by t4 in FIG. 12, the oil supply chamber pump 27f and the remaining fuel chamber pump 27r are operated, and only the in-cylinder injection valve 18c is operated. As a result, the ratio of the fuel burned in the combustion chamber 5 can be maintained at the above-described predetermined ratio. In this case, the fuel chamber pump 27f discharges so that the fuel in the fuel chamber 19f and the fuel in the remaining fuel chamber 19r are supplied to the in-cylinder injection valve 18c at a predetermined ratio (q: (1-q)). The amount and the discharge amount of the remaining fuel chamber pump 27r are controlled, so that the metering device can be omitted.

  FIG. 15 shows still another embodiment according to the present invention. In the example shown in FIG. 15, the in-cylinder injection valve 18c is connected only to the fuel supply fuel chamber 19f via the in-cylinder injection valve delivery pipe 26c, the in-cylinder injection valve supply pipe 25c, and the fuel supply branch pipe 23f, and the port injection The valve 18p is connected only to the remaining fuel chamber 19r through the port injection valve delivery pipe 26p, the port injection valve supply pipe 25p, and the fuel supply branch pipe 23r. As a result, only the fuel in the fuel supply chamber 19f is supplied to the engine from the cylinder injection valve 18c, and only the fuel in the remaining fuel chamber 19r is supplied to the engine from the port injection valve 18p.

  In the example shown in FIG. 15, when the engine operation is resumed after refueling, only the remaining fuel chamber pump 27r is operated and only the port injection valve 18p is operated, as indicated by t3 in FIG. Therefore, only the fuel in the remaining fuel chamber 19r is supplied from the port injection valve 18p to the engine.

  Next, when the property correction coefficient kFa is to be calculated, as indicated by t4 in FIG. 16, the oil supply chamber pump 27f and the remaining fuel chamber pump 27r are operated, and the in-cylinder injection valve 18c and the port injection valve 18p are operated. In this case, the fuel injection time TAUC of the in-cylinder injection valve 18c is set to TAU · q, and the fuel injection time TAUP of the port injection valve 18p is set to TAU · (1-q), so that the fuel in the fuel supply chamber 19f is set. The fuel in the remaining fuel chamber 19r is supplied to the engine at a predetermined ratio (q: (1-q)). As a result, the ratio of the fuel combusted in the combustion chamber 5 can be maintained at the above-described predetermined ratio, and the metering device can be omitted.

  Also in the embodiment shown in FIG. 15, during normal operation, for example, fuel is supplied from the in-cylinder injection valve 18c or the port injection valve 18p to the engine in accordance with the engine operating state. For example, only the in-cylinder injection valve 18c is used to supply fuel to the engine during low engine load operation, and only the port injection valve 18p is used during high load operation. Further, both the in-cylinder injection valve 18c and the port injection valve 18p can be used. In the example shown in FIG. 16, only the in-cylinder injection valve 18c is used for fuel supply during normal operation before refueling, and only the port injection valve 18p is used during normal operation after calculating the property correction coefficient kFa.

  FIG. 17 shows a refueling aftertreatment routine according to still another embodiment of the present invention. This routine is executed by interruption every predetermined time.

  Referring to FIG. 17, first, at step 140, it is judged if the calculation flag is reset. Since the calculation flag is reset when the engine operation is resumed after refueling, the routine proceeds to step 141 where it is determined whether or not the feedback control execution condition is satisfied. When the feedback control execution condition is not satisfied, the routine proceeds to step 142 where the fuel chamber pump 27f is stopped and the remaining fuel chamber pump 27r is operated. In the subsequent step 142b, the fuel injection time TAUC of the in-cylinder injection valve 18c is set to zero, and the fuel injection time TAUP of the port injection valve 18p is set to TAU. That is, in this case, the fuel in the remaining fuel chamber 19r is supplied to the engine only from the port injection valve 18p. In subsequent step 143, the property correction coefficient kF is set to the property correction coefficient kFr for the fuel in the remaining fuel chamber 19r.

  Next, when the feedback control execution condition is satisfied, the routine proceeds from step 141 to step 144, where the fueling chamber pump 27f and the remaining fuel chamber pump 27r are operated. In the following step 144b, the fuel injection time TAUC of the in-cylinder injection valve 18c is set to TAU · q, and the fuel injection time TAUP of the port injection valve 18p is set to TAU · (1-q). That is, in this case, the fuel in the fuel supply chamber 19f is injected from the in-cylinder injection valve 18c, the fuel in the remaining fuel chamber 19r is supplied from the port injection valve 18p, and the fuel in the fuel supply chamber 19f and the fuel in the remaining fuel chamber 19r. Is supplied to the engine at a predetermined rate. In the subsequent step 145, a routine for calculating the property correction coefficient kFa shown in FIG. 9 is executed.

  When the calculation flag is set in the calculation routine for the property correction coefficient kFa, the routine proceeds from step 140 to step 146, where the shutoff valve 20 is opened. In the subsequent step 147b, the fuel supply chamber pump 27f, the remaining fuel chamber pump 27r, the cylinder injection valve 18c, and the port injection valve 18p are normally controlled. In the following step 148, the property correction coefficient kF is set to kFa calculated by the routine of FIG.

  Other configurations and operations of the embodiment shown in FIG. 15 are the same as those of the embodiment shown in FIG.

  Each embodiment described so far shows a case where the present invention is applied to air-fuel ratio control or fuel injection amount control. However, the present invention can also be applied to ignition timing control that maintains the ignition timing at an optimal ignition timing such as MBT, and to rotation speed control that maintains the idling rotation speed at the target rotation speed.

1 is an overall view of an internal combustion engine. It is a figure which shows the output of an oxygen concentration sensor. It is a time chart for demonstrating the calculation method of the feedback correction coefficient FAF. It is a flowchart which shows the calculation routine of the feedback correction coefficient FAF. It is a time chart for demonstrating the calculation method of property correction coefficient kF. It is a time chart for demonstrating the Example by this invention. It is a flowchart which shows a refueling pre-processing routine. It is a flowchart which shows a refueling post-processing routine. It is a flowchart which shows the calculation routine of property correction coefficient kFa. It is a flowchart which shows the calculation routine of fuel injection time TAU. It is a general view of the internal combustion engine of another Example by this invention. It is a time chart for demonstrating another Example by this invention. It is a flowchart which shows the refueling post-processing routine of another Example by this invention. It is a general view of the internal combustion engine of the modification of another Example by this invention. It is a general view of the internal combustion engine of another Example by this invention. It is a time chart for demonstrating another Example by this invention. It is a flowchart which shows the refueling post-processing routine of another Example by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine body 18c In-cylinder injection valve 18p Port injection valve 19 Fuel tank 19f Refueling chamber 19r Remaining fuel chamber 19w Partition 20 Shutoff valve

Claims (2)

  The fuel tank is provided with a fuel chamber and a residual fuel chamber that can communicate with each other or shut off, and when fueling is performed, the fuel chamber and the residual fuel chamber that have been communicated with each other are shut off from each other and then only the fuel chamber is filled. When the engine operation is resumed after refueling, only the fuel in the remaining fuel chamber is first supplied to the engine while the fuel chamber and the remaining fuel chamber are shut off from each other, and the fuel in the remaining fuel chamber determined in advance is supplied. When the engine control is performed according to the properties, and then a predetermined condition is satisfied, the fuel chamber and the remaining fuel chamber are shut off from each other, and the fuel in the fuel chamber and the fuel in the remaining fuel chamber are set in a predetermined ratio. The fuel is supplied to the engine at the predetermined rate based on the engine state quantity obtained at this time, and the property of the fuel supplied to the engine is obtained at the predetermined rate. Based on the properties of the supplied fuel and the properties of the remaining fuel obtained in advance, the average properties of the fuel in the fueling chamber and the fuel in the remaining fuel chamber are obtained, and then the fueling chamber and the remaining fuel chamber are connected to each other to connect the fueling chamber. The fuel in the remaining fuel chamber and the fuel in the remaining fuel chamber are mixed with each other, the fuel is supplied to the engine from at least one of the fueling chamber and the remaining fuel chamber, and the engine is controlled according to the obtained average fuel property. A control device for an internal combustion engine.   A reference fuel chamber containing a reference fuel whose properties are known in advance and a target fuel chamber containing a target fuel whose properties are unknown are supplied to the engine at a predetermined ratio. In addition, a fuel property detection device for an internal combustion engine that obtains the property of the target fuel or the average property of the fuel in the reference fuel chamber and the fuel in the target fuel chamber based on the engine state quantity and the property of the reference fuel obtained at this time.

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