JP2016044561A - Fuel injection control device and fuel injection control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injection control device which can reduce deviation between a target amount and an actual injection amount in target amounts which are different from each other, and a fuel injection control method.SOLUTION: A fuel injection control device 50 comprises a storage part 53 which stores an injection character map 54, and an injection control part which calculates a target amount of a fuel injection valve 13, and drives the fuel injection valve in a drive time based on the target amount and the fuel injection character map 54. The fuel injection control device 50 calculates a second target amount which is obtained by adding an oscillation component to a first target amount which corresponds to a drive state as the target amount, and drives the fuel injection valve 13 in a trial time being a drive time of the second target amount. Furthermore, the fuel injection control device calculates an air-fuel ratio of a cylinder 12 corresponding to the fuel injection valve 13 which is driven for the trial time on the basis of a detection value of an air-fuel ratio sensor 36, and calculates a correction injection amount based on the air-fuel ratio and an air amount which is sucked by the cylinder 12. Then, the fuel injection control device corrects the fuel character map 54 on the basis of correction data 56 which are constituted of a plurality of pieces of data which are obtained by making the trial time and the correction injection amount associated with each other.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fuel injection control device and a fuel injection control method for controlling an injection amount from a fuel injection valve.

  2. Description of the Related Art Conventionally, in an engine system, a drive time of a fuel injection valve that opens during driving is controlled by a fuel injection control device. The fuel injection control device calculates, for example, the fuel amount corresponding to the engine operating state based on the engine speed and the accelerator opening as the target amount. The fuel injection control device obtains a drive time corresponding to the target amount from the injection characteristic indicating the relationship between the drive time of the fuel injection valve and the injection amount with respect to the drive time, and drives the fuel injection valve for the obtained drive time. .

  On the other hand, when the injection characteristic of the fuel injection valve changes due to deterioration over time, the difference between the target amount and the actual injection amount increases. Such divergence leads to a decrease in engine output and a reduction in exhaust gas purification ability. For this reason, in Patent Document 1, in order to bring the actual injection amount closer to the target amount, the drive time for the target amount is based on the injection amount correction coefficient calculated from the difference between the average effective pressure in the cylinder and the target average effective pressure. A technique for correcting the above is disclosed.

JP 2008-196361 A

  However, in the method of Patent Document 1, the driving time for the target amount is uniformly increased or decreased by the injection amount correction coefficient. For this reason, for example, when the amount to be corrected is different between when the target amount is small and when the target amount is large, there is a possibility that the difference between the actual injection amount and the target amount may not be improved.

  It is an object of the present invention to provide a fuel injection control device and a fuel injection control method that can reduce the difference between the target amount and the actual injection amount at different target amounts.

  A fuel injection control device that solves the above problems includes a storage unit that stores an injection characteristic map that indicates a relationship between a drive time of a fuel injection valve and an injection amount, and an injection amount that corresponds to an operating state of the engine as a first target amount. An injection control unit that calculates and calculates the drive time corresponding to the first target amount from the injection characteristic map, and controls the drive time of the fuel injection valve to the calculated drive time; and an exhaust passage of the engine An air-fuel ratio calculation unit that calculates an air-fuel ratio of a cylinder corresponding to the fuel injection valve driven for the drive time based on a detection value of an air-fuel ratio sensor provided, and the injection control unit includes the first A second target amount obtained by adding a swing component to one target amount, which is different from each other in different injection strokes, and corresponds to the second target amount from the injection characteristic map. The driving time A certain trial time is obtained for each injection stroke, the driving time of the fuel injection valve is controlled to the obtained trial time, and the cylinder corresponding to the fuel injection valve driven for the trial time is compared with the cylinder The injection characteristic map is calculated from the trial time and the corrected injection amount for each injection stroke by calculating a corrected injection amount that is a fuel amount based on the amount of air sucked in and the air-fuel ratio of the cylinder for each injection stroke. A correction unit is further provided for correcting.

  A fuel injection method that solves the above problem includes a storage unit that stores an injection characteristic map that indicates a relationship between a drive time of a fuel injection valve and an injection amount, and an injection amount that corresponds to the operating state of the engine is calculated as a first target amount. An injection control unit that obtains the drive time corresponding to the first target amount from the injection characteristic map and controls the drive time of the fuel injection valve to the obtained drive time, and an exhaust passage of the engine And a fuel injection control device comprising: an air-fuel ratio calculation unit that calculates an air-fuel ratio of a cylinder corresponding to the fuel injection valve driven for the drive time based on the detected value of the air-fuel ratio sensor. The fuel injection control apparatus calculates a second target amount that is a second target amount obtained by adding a swing component to the first target amount, and that is different from each other in different injection strokes. The jet A trial time, which is the drive time corresponding to the second target amount, is determined for each injection stroke from a property map, the drive time of the fuel injection valve is controlled to the obtained trial time, and is driven for the trial time. For each of the cylinders corresponding to the fuel injection valve, a corrected injection amount, which is a fuel amount based on the amount of air taken in by the cylinder and the air-fuel ratio of the cylinder, is calculated for each injection stroke. The injection characteristic map is corrected from the trial time and the corrected injection amount.

  According to the above configuration, the injection characteristic map is corrected based on a plurality of data instead of one data in which the trial time is associated with the corrected injection amount for the trial time. Thus, the injection characteristic map is changed to an injection characteristic map that more reflects the changed injection characteristic. As a result, even if the injection characteristic of the fuel injection valve changes, the difference between the target amount and the actual injection amount becomes small. In addition, since the second target amounts are different from each other in different injection strokes, the injection characteristic map can be corrected even when the engine is in a steady state, that is, the first target amount is substantially constant.

  The fuel injection device further includes a correction target detection unit that detects a correction target that is the fuel injection valve whose injection characteristic has changed among the plurality of fuel injection valves of the engine, and the storage unit includes the plurality of fuel injection valves. The injection characteristic map is separately stored for each fuel injection valve, and the injection control unit calculates the second target amount of the correction target and obtains the trial time from the injection characteristic map corresponding to the correction target. Preferably, the drive time of the correction target is controlled to the obtained trial time, and the correction unit corrects the injection characteristic map corresponding to the correction target.

  According to the above configuration, when the engine has a plurality of fuel injection valves, the fuel injection valve whose injection characteristic has changed is detected as a correction target, and the injection characteristic map corresponding to the correction target is corrected. Thereby, the injection characteristic map corresponding to the fuel injection valve in which the injection characteristic has changed can be corrected separately.

In the fuel injection control apparatus, it is preferable that the correction target detection unit detects the correction target when the operating state of the engine is in a steady state.
According to the above configuration, since the air-fuel ratios of all the cylinders are stable in the steady state, it is possible to detect the fuel injection valve whose injection characteristic has changed with high accuracy.

  In the fuel injection control device, the air-fuel ratio calculation unit calculates the air-fuel ratio for each of a plurality of cylinders of the engine, and the correction target detection unit calculates an average value of the air-fuel ratios in the plurality of cylinders and the air-fuel ratio. Preferably, a deviation from the air-fuel ratio for each cylinder is calculated, and the fuel injection valve that injects fuel into the cylinder having the abnormal deviation is detected as the correction target.

  As described above, the correction target can be detected in a steady state depending on whether or not the deviation between the average value of the air-fuel ratios of all the cylinders and the air-fuel ratio of each cylinder is an abnormal value.

The figure which shows schematic structure of the engine system carrying one Embodiment of a fuel-injection control apparatus. The graph which shows an example of an injection characteristic map typically. The flowchart which shows an example of the process which detects correction | amendment object. The flowchart which shows an example of the process which correct | amends an injection characteristic map. The graph which shows an example of correction | amendment of an injection characteristic map typically.

With reference to FIGS. 1-5, one Embodiment of a fuel-injection control apparatus is described. With reference to FIG. 1, the whole structure of the engine system in which the fuel injection control device is mounted will be described.
As shown in FIG. 1, the engine 10 of the engine system has six cylinders 12 in a cylinder block 11. The engine 10 is an MPI (Multi Point Injection) engine, and has a fuel injection valve 13 for injecting fuel into the cylinder 12 for each cylinder 12. An intake manifold 14 for supplying intake air to each cylinder 12 and an exhaust manifold 15 into which exhaust gas from each cylinder 12 flows are connected to the cylinder block 11.

  In the intake passage 16 connected to the intake manifold 14, an air cleaner (not shown), a compressor 18 constituting a turbocharger 17, an intercooler 19, a throttle valve 20, and a surge tank 21 are provided in order from the upstream side. The exhaust passage 25 connected to the exhaust manifold 15 is provided with a turbine 26 that is connected to the compressor 18 via a connecting shaft and constitutes the turbocharger 17.

  The engine system includes an intake air amount sensor 30, an intake pressure sensor 31, an intake air temperature sensor 32, a crank angle sensor 34, a cam angle sensor 35, an air-fuel ratio sensor 36, a coolant temperature sensor 37, and an accelerator opening sensor 38.

  The intake air amount sensor 30 detects an intake air amount Qa that is a volume flow rate of intake air flowing through the intake passage 16 upstream of the compressor 18 in the intake passage 16. The intake pressure sensor 31 detects an intake pressure Pb that is the pressure of intake air in the surge tank 21. The intake air temperature sensor 32 detects an intake air temperature ti that is the temperature of intake air in the surge tank 21. The crank angle sensor 34 detects a crank angle CA that is a rotation angle of the crankshaft 10a. The cam angle sensor 35 outputs a cylinder discrimination signal G at a timing when a predetermined cylinder 12 reaches the compression top dead center based on a rotation angle of a camshaft (not shown). The air-fuel ratio sensor 36 detects the air-fuel ratio λ, which is the ratio of the weight of air to the weight of fuel in the air-fuel mixture, based on the oxygen concentration contained in the exhaust gas flowing out from the turbine 26. The cooling water temperature sensor 37 detects the cooling water temperature tw that is the temperature of the cooling water that cools the engine 10. The accelerator opening sensor 38 detects an accelerator opening ACC that is a depression amount of the accelerator pedal 39. The signals output from the sensors 30 to 38 are input to a fuel injection control device 50 (hereinafter simply referred to as the control device 50).

  The control device 50 is mainly configured by a microcomputer having a CPU, a ROM, and a RAM. The control device 50 includes an acquisition unit 51 that acquires various types of information based on signals from each sensor, a processing unit 52 that executes various types of processing, and a storage unit 53 that stores various types of control programs and various types of data. The processing unit 52 performs various processes based on various control programs stored in the storage unit 53 and information input from the sensors 30 to 38.

  Based on signals from various sensors, the acquisition unit 51 receives the intake air amount Qa, the intake pressure Pb, the intake air temperature ti, the crank angle CA, the cylinder discrimination signal G, the air-fuel ratio λ, the cooling water temperature tw, and the accelerator opening ACC. To get. The acquisition unit 51 acquires the engine speed Ne, which is the rotation speed of the crankshaft 10a, based on the signal from the crank angle sensor 34.

  As shown in FIG. 2, the storage unit 53 stores, as various data, an injection characteristic map 54 in which the drive time Tr of the fuel injection valve 13 with respect to the target amount Gft is defined for each fuel injection valve 13. Yes.

  Based on the cylinder discrimination signal G and the signal from the crank angle sensor 34, the processing unit 52 sets the injection target that is the fuel injection valve 13 that injects fuel and the injection timing of the injection target. The processing unit 52 is a first target amount that is the weight of fuel suitable for the operating state of the engine 10 based on the intake air amount Qa, the intake pressure Pb, the intake air temperature ti, the engine speed Ne, the accelerator opening degree ACC, and the like. Gf1 is calculated as a target amount Gft to be injected. The processing unit 52 sets the drive time Tr to be injected based on the calculated target amount Gft and the injection characteristic map 54. The processing unit 52 outputs a signal indicating the injection target and the driving time Tr to the driving current generating unit 55. The drive current generation unit 55 generates a drive current based on the signal from the processing unit 52, and outputs the generated drive current to the ejection target.

  The processing unit 52 calculates the air-fuel ratio λ of each cylinder 12. The processing unit 52 calculates the timing at which the exhaust gas discharged from the cylinder 12 reaches the air-fuel ratio sensor 36 for each cylinder 12 based on the cylinder discrimination signal G and the signal from the crank angle sensor 34. The processing unit 52 calculates the air-fuel ratio λ of each cylinder 12 based on the signal from the air-fuel ratio sensor 36 at that timing.

  The processing unit 52 detects a correction target that is the fuel injection valve 13 whose injection characteristic has changed. The processing unit 52 detects a correction target when the warm-up of the engine 10 is completed and the operating state of the engine 10 is a steady state. The processing unit 52 determines that the warm-up has been completed on condition that the coolant temperature tw is equal to or higher than the warm-up completion temperature tw1, which is a temperature at which it is determined that the engine 10 has been warmed up. The steady state is a state in which the fluctuation of the load of the engine 10 is small. For example, the engine speed Ne, the accelerator opening ACC, and the target amount Gft are substantially constant. The processing unit 52 calculates the average value λave of the air-fuel ratio λ of all the cylinders 12 from the calculation result of the air-fuel ratio λ, and calculates the deviation Δλ between the calculated average value λave and the air-fuel ratio λ of the cylinder 12 for each cylinder 12. To do. The processing unit 52 determines whether or not the absolute value of the deviation Δλ is an abnormal value with a value larger than the threshold value Δλth determined to have changed the injection characteristic as an abnormal value. When there is a cylinder 12 in which the absolute value of the deviation Δλ is an abnormal value, the processing unit 52 detects the fuel injection valve 13 corresponding to the cylinder as a correction target.

  When the fuel injection valve 13 that is not the correction target is set as the injection target, the processing unit 52 that has detected the correction target calculates the first target amount Gf1 as the target amount Gft. On the other hand, when the fuel injection valve 13 that is the correction target is set as the injection target, the processing unit 52 adds the swing component d to the first target amount Gf1 by a predetermined sampling number of 2 or more. 2 The target amount Gf2 is calculated as the target amount Gft. The processing unit 52 obtains the driving time Tr corresponding to the second target amount Gf2 from the injection characteristic map 54 as the trial time Tt, and drives the fuel injection valve 13 at the obtained trial time Tt. The swing component d is, for example, an addition value for the first target amount Gf1 or a multiplication value of 1 or more for the first target amount Gf1, and the amount of fuel supplied to the correction target is changed to the second target amount Gf2. It is preferable that the driver cannot experience this. It is preferable that the processing unit 52 calculates a second target amount Gf2 that is different from one another for each sampling.

  For each sampling, the processing unit 52 determines the amount of air taken in by the cylinder 12 based on the intake air amount Qa, the intake pressure Pb, the intake air temperature ti, and the engine speed Ne used for the calculation of the first target amount Gf1. The air amount Ga which is weight is calculated. Based on the air amount Ga and the air-fuel ratio λ of the cylinder 12 corresponding to the correction target, the processing unit 52 calculates a correction injection amount Gfc that is the correction target injection amount. The processing unit 52 generates correction data 56 by storing data in which the trial time Tt and the correction injection amount Gfc are associated with each other in the predetermined area of the storage unit 53 by the number of samplings.

  The processing unit 52 corrects the injection characteristic map 54 corresponding to the correction target based on the correction data 56. For example, the processing unit 52 obtains an approximate line by a least square method using a specific function, and corrects the injection characteristic map by obtaining the drive time Tr of each target amount Gft from the obtained approximate line.

  Thus, the processing unit 52 functions as an injection control unit, an air-fuel ratio calculation unit, an injection amount calculation unit, and a correction unit. The number of samplings is preferably the number of samplings according to the correction method of the injection characteristic map 54 and the number of samplings with which sufficient reliability can be obtained in the corrected injection characteristic map 54.

With reference to FIG. 3, an example of processing for detecting a correction target will be described. This process includes starting the engine 10 and correcting the injection characteristic map 54 as the start timing.
As shown in FIG. 3, the processing unit 52 first determines whether or not the operating state of the engine 10 is a steady state after completion of warm-up (step S11). When the operating state of the engine 10 is not a steady state after completion of warm-up (step S11: NO), the processing unit 52 once ends a series of processes.

  On the other hand, when the operating state of the engine 10 is a steady state after completion of warm-up (step S11: YES), the processing unit 52 calculates the air-fuel ratio λ of each cylinder 12 (step S12). Further, the processing unit 52 calculates an average value λave of the air-fuel ratios λ of all the cylinders 12 (step S13).

  In the next step S14, the processing unit 52 calculates the deviation Δλ between the air-fuel ratio λ and the average value λave for each cylinder 12, and is an absolute value greater than the threshold value Δλth at which it is determined that the injection characteristic of the fuel injection valve 13 has changed. It is determined whether or not there is a large deviation Δλ. When all the deviations Δλ are equal to or smaller than the threshold value Δλth (step S14: NO), the processing unit 52 once ends a series of processing.

  On the other hand, when there is a deviation Δλ having an absolute value larger than the threshold value Δλth (step S14: YES), the processing unit 52 sets the fuel injection valve 13 corresponding to the cylinder 12 having the deviation Δλ as a correction target (step S15). ). And the process part 52 performs the process which correct | amends the injection characteristic map 54 corresponding to correction object.

An example of processing for correcting the injection characteristic map 54 will be described with reference to FIG.
As illustrated in FIG. 4, the processing unit 52 first acquires various types of information via the acquisition unit 51 (step S21). In the next step S22, the processing unit 52 determines whether or not the fuel injection valve 13 set as an injection target is a correction target (step S22). When the injection target is not the correction target (step S22: NO), the processing unit 52 proceeds to the process of step S21. On the other hand, when the injection target is the correction target (step S22: YES), the processing unit 52 calculates the second target amount Gf2 as the target amount Gft (step S23). The processing unit 52 drives the correction target with the driving time Tr corresponding to the second target amount Gf2 as the trial time Tt (step S24).

  In the next step S25, the processing unit 52 calculates the air-fuel ratio λ of the cylinder 12 corresponding to the fuel injection valve 13 to be corrected. Further, in step S26, the processing unit 52 is based on the intake air amount Qa, the intake pressure Pb, the air amount Ga based on the intake air temperature ti acquired in step S21, and the air-fuel ratio λ calculated in step S25. The corrected injection amount Gfc is calculated.

  Next, the processing unit 52 associates the trial time Tt based on the second target amount Gf2 calculated in step S23 with the corrected injection amount Gfc calculated in step S26, and stores it in a predetermined area of the storage unit 53 ( Step S27), the correction data 56 is constructed. Next, the processing unit 52 determines whether or not the correction target sampling is completed (step S28).

  When the sampling is not completed (step S28: NO), the processing unit 52 proceeds to the process of step S21 again. On the other hand, when the sampling is completed (step S28: YES), the processing unit 52 corrects the injection characteristic map 54 to be corrected based on the correction data 56 (step S29), and ends the series of processes.

The operation of the control device 50 configured as described above will be described.
The control device 50 detects the fuel injection valve 13 whose injection characteristic has changed, and corrects the injection characteristic map 54 corresponding to the fuel injection valve 13. The control device 50 corrects the injection characteristic map 54 based on correction data 56 composed of a plurality of data in which the trial time Tt and the correction injection amount Gfc are associated with each other.

  That is, as shown in FIG. 5, when the driving time Tr with respect to the target amount Gft is uniformly increased or decreased based on one sampling, the basic injection characteristic 60 is obtained by parallel movement based only on (Gft1, Tr1) in FIG. The injection characteristic 61 is corrected. On the other hand, in the correction of the injection characteristic map 54 described above, (Gft2, Tr2) and (Gft3, Tr3) are added in addition to (Gft1, Tr1). Therefore, since the injection characteristic map 54 is corrected to the injection characteristic 62 that more reflects the changed injection characteristic, the difference between the target amount Gft and the actual injection amount is reduced.

  Then, by setting the target amount Gft to be corrected to the second target amount Gf2 that is different for each injection stroke, even if the operating state of the engine 10 is a steady state where the change in the first target amount Gf1 is small, a plurality of target amounts Gft2 are set. The injection characteristic map 54 can be corrected based on the sampling.

According to the fuel injection control device 50 of the above embodiment, the effects listed below can be obtained.
(1) The injection characteristic map 54 is corrected based on a plurality of samplings. As a result, the difference between the target amount Gft and the actual injection amount becomes small.

  (2) A correction target is detected from the plurality of fuel injection valves 13, and the injection characteristic map 54 corresponding to the correction target is corrected. As a result, even if only one fuel injection valve 13 among the plurality of fuel injection valves 13 is detected as a correction target, the correction is made without affecting the injection characteristic map 54 corresponding to the other fuel injection valves 13. Only the injection characteristic map 54 corresponding to the object can be corrected.

  (3) The correction target is detected when the operating state of the engine 10 is a steady state. In the steady state, since the fluctuation of the load on the engine 10 is small and the air-fuel ratios of all the cylinders are stable, it is possible to detect the fuel injection valve 13 whose injection characteristics have changed with high accuracy.

(4) In a steady state, the correction target can be detected based on the deviation Δλ between the average value λave of the air-fuel ratio λ and the air-fuel ratio λ for each cylinder 12.
In addition, the said embodiment can also be suitably changed and implemented as follows.
The processing unit 52 detects, as a correction target detection unit, the fuel injection valve 13 corresponding to the cylinder 12 whose absolute value of the deviation Δλ is larger than the threshold value Δλth as a correction target. That is, a threshold value that is determined as an abnormal value when the deviation Δλ is a positive value, a threshold value that is determined as an abnormal value when the deviation Δλ is a negative value, and these are the same size. The processing unit 52 is not limited to this, and the threshold value when the deviation Δλ is a positive value may be different from the threshold value when the deviation Δλ is a negative value. According to this configuration, for example, the threshold value can be set according to the deterioration characteristic of the fuel injection valve 13.

  The processing unit 52 serves as a correction target detection unit, for example, an air-fuel ratio λ calculated based on a signal from the air-fuel ratio sensor 36, an air-fuel ratio λ1 calculated based on the first target amount Gf1 and the air amount Ga, these The correction target may be detected on the condition that the absolute value of the deviation Δλ1 is larger than the threshold value Δλ1th. According to this configuration, the effects equivalent to the above (1) and (2) can be obtained, and the correction target can be detected not only when the operation state of the engine 10 is in a steady state but also in an acceleration state, for example. it can.

  In the above configuration, the threshold value Δλ1th may be a constant value or a value that varies according to the operating state of the engine 10. When the threshold value Δλ1th varies, the threshold value Δλ1th is preferably a minimum value in a steady state of the engine 10, for example.

  The processing unit 52 may specify the correction target as a correction target detection unit based on a change in the engine speed Ne based on a signal from the crank angle sensor 34 in a steady state of the engine 10, for example.

  The control device 50 can also be applied to a single point injection (SPI) engine that supplies fuel to each cylinder 12 by injecting fuel to the intake air flowing into each cylinder 12.

The intake air amount sensor 30 may detect the mass flow rate of intake air flowing through the intake passage 16. In such a case, the air amount Ga is a detection value of the intake air amount sensor 30.
The engine 10 to which the control device 50 is applied may be a gasoline engine, a gas engine, or a diesel engine.
The first target amount Gf1 may be calculated taking into account, for example, the outside air temperature or the fuel temperature.

  By setting the second target amount Gf2 obtained by adding the swing component d to the first target amount Gf1 as the target amount Gft of the specific fuel injection valve 13, the following can also be realized.

  For example, the target amount Gft of the specific fuel injection valve 13 is set to the second target amount Gf2 on condition that the injection characteristics of the fuel injection valve 13 are substantially the same and the engine 10 is in a steady state. In this case, the air-fuel ratio λ of the cylinder 12 corresponding to the specific fuel injection valve 13 is different from the air-fuel ratio λ of the other cylinders 12. Based on the difference in the air-fuel ratio λ, it is possible to grasp the timing at which the exhaust gas discharged from the cylinder corresponding to the specific fuel injection valve 13 reaches the air-fuel ratio sensor 36. That is, even when the distance to the air-fuel ratio sensor 36 is different for each cylinder 12, it is possible to grasp which portion of the signal output from the air-fuel ratio sensor 36 corresponds to the specific fuel injection valve 13. Can do.

  Further, for example, when the air-fuel ratio λ of the cylinder 12 corresponding to the specific fuel injection valve 13 is the same value as the air-fuel ratio λ of the other cylinders 12 or a value deviating from the normal range, the specific fuel It is also possible to determine whether the injection valve 13 is normal or abnormal.

  Further, for example, the difference between the air-fuel ratio λ of the cylinder 12 corresponding to the specific fuel injection valve 13 and the air-fuel ratio λ of the other cylinder 12, the difference between the first target amount Gf1 and the second target amount Gf2, based on these It is also possible to determine the degree of deterioration of the air-fuel ratio sensor 36 and the presence or absence of abnormality.

  DESCRIPTION OF SYMBOLS 10 ... Engine, 10a ... Crankshaft, 11 ... Cylinder block, 12 ... Cylinder, 13 ... Fuel injection valve, 14 ... Intake manifold, 15 ... Exhaust manifold, 16 ... Intake passage, 17 ... Turbocharger, 18 ... Compressor, 19 ... Intercooler, 20 ... throttle valve, 21 ... surge tank, 25 ... exhaust passage, 26 ... turbine, 30 ... intake air amount sensor, 31 ... intake air pressure sensor, 32 ... intake air temperature sensor, 34 ... crank angle sensor, 35 ... cam angle Sensor: 36 ... Air-fuel ratio sensor, 37 ... Cooling water temperature sensor, 38 ... Accelerator opening sensor, 39 ... Accelerator pedal, 50 ... Fuel injection control device, 51 ... Acquisition unit, 52 ... Processing unit, 53 ... Storage unit, 54 ... Injection characteristic map, 55... Drive current generator, 56. , 60 ... the basic injection characteristic, 61, 62 ... injection characteristics.

Claims (5)

A storage unit for storing an injection characteristic map indicating a relationship between a drive time of the fuel injection valve and an injection amount;
The injection amount corresponding to the operating state of the engine is calculated as a first target amount, the drive time corresponding to the first target amount is obtained from the injection characteristic map, and the drive time of the fuel injection valve is obtained. An injection controller that controls the time,
An air-fuel ratio calculating section for calculating an air-fuel ratio of a cylinder corresponding to the fuel injection valve driven for the drive time based on a detection value of an air-fuel ratio sensor provided in an exhaust passage of the engine;
With
The injection control unit calculates a second target amount, which is a second target amount obtained by adding a swing component to the first target amount, and is different from each other in different injection strokes, from the injection characteristic map Obtaining a trial time, which is the drive time corresponding to the second target amount, for each injection stroke, and controlling the drive time of the fuel injection valve to the obtained trial time;
For the cylinder corresponding to the fuel injection valve driven for the trial time, a corrected injection amount, which is a fuel amount based on the air amount sucked by the cylinder and the air-fuel ratio of the cylinder, is calculated for each injection stroke. The fuel injection control device further includes a correction unit that corrects the injection characteristic map from the trial time and the corrected injection amount for each injection stroke. A correction target detection unit for detecting a correction target that is the fuel injection valve whose injection characteristic has changed among the plurality of fuel injection valves of the engine;
The storage unit stores the injection characteristic map for each of the plurality of fuel injection valves,
The injection control unit calculates the second target amount of the correction target, calculates the trial time from the injection characteristic map corresponding to the correction target, and sets the driving time of the correction target to the calculated trial time. Control
The fuel injection control device according to claim 1, wherein the correction unit corrects the injection characteristic map corresponding to the correction target. The correction target detection unit
The fuel injection control device according to claim 2, wherein the correction target is detected when the operating state of the engine is in a steady state. The air-fuel ratio calculation unit is
Calculating the air-fuel ratio for each of a plurality of cylinders of the engine;
The correction target detection unit
A deviation between an average value of air-fuel ratios in the plurality of cylinders and the air-fuel ratio for each cylinder is calculated, and the fuel injection valve that injects fuel into a cylinder having the abnormal deviation is detected as the correction target. Item 4. The fuel injection control device according to Item 2 or 3. A storage unit for storing an injection characteristic map indicating a relationship between a drive time of the fuel injection valve and an injection amount;
The injection amount corresponding to the operating state of the engine is calculated as a first target amount, the drive time corresponding to the first target amount is obtained from the injection characteristic map, and the drive time of the fuel injection valve is obtained. An injection controller that controls the time,
An air-fuel ratio calculation unit that calculates an air-fuel ratio of a cylinder corresponding to the fuel injection valve driven for the drive time based on a detection value of an air-fuel ratio sensor provided in an exhaust passage of the engine; A fuel injection control method performed by a control device,
The fuel injection control device includes:
A second target amount obtained by adding a swing component to the first target amount, and calculating the second target amount that is different from each other in different injection strokes, from the injection characteristic map to the second target amount. A trial time that is the corresponding drive time is obtained for each injection stroke, and the drive time of the fuel injection valve is controlled to the obtained trial time,
For the cylinder corresponding to the fuel injection valve driven for the trial time, a corrected injection amount, which is a fuel amount based on the air amount sucked by the cylinder and the air-fuel ratio of the cylinder, is calculated for each injection stroke. A fuel injection control method for correcting the injection characteristic map from the trial time and the corrected injection amount for each injection stroke.

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