JP3734324B2 - Vehicle engine control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicular engine control device that electrically controls the opening of a throttle valve.
[0002]
[Prior art]
Conventionally, as a vehicular engine control device, the throttle valve is not directly opened and closed by a link mechanism interlocked with the accelerator pedal, but the operation amount of the accelerator pedal (accelerator operation amount) is electrically detected and detected. An engine control apparatus employing a so-called linkless throttle system in which the opening degree of a throttle valve is controlled by an electric actuator such as a motor in accordance with an accelerator operation amount has been put into practical use.
[0003]
And in this type of engine control device, it is always monitored whether or not the drive control system of the throttle valve, such as the actuator itself and the drive circuit for operating the actuator, is normal, and when it is determined that an abnormality has occurred, For example, the energization of the actuator is forcibly stopped or the so-called fuel cut for stopping the fuel supply to the engine is performed.
[0004]
That is, in normal engine control, the amount of air flowing into the engine (intake air amount) is detected by opening the throttle valve, and the fuel supply amount to the engine is determined according to the detected intake air amount. If the throttle valve drive control system malfunctions and the throttle valve opens greatly against the driver's intention, the fuel supply amount will increase accordingly. This is because the engine torque may increase.
[0005]
However, even if it is configured to perform the fail-safe as described above, if the abnormality detection circuit for detecting an abnormality breaks down at the same time, there is no longer anything to do.
Therefore, as a technique for solving such a rare case defect, for example, in Japanese Patent Application Laid-Open No. 63-147940, an upper limit value of the fuel supply amount is set in accordance with the accelerator operation amount, and the vehicle is operated. When the fuel supply amount determined according to the state exceeds the set upper limit value, it has been proposed to perform control such as limiting the fuel supply amount to the upper limit value.
[0006]
According to this technique, the engine torque is unnecessarily increased even in the worst case such that the drive control system of the throttle valve and the abnormality detection circuit for detecting abnormality thereof are simultaneously broken. This can be prevented.
[0007]
[Problems to be solved by the invention]
However, the technique disclosed in the above publication has the following problems because the upper limit value of the fuel supply amount is set based on the operation amount of the accelerator pedal operated by the driver.
[0008]
For example, when so-called auto-cruise control is performed in which the vehicle travels at a constant speed set by the driver, the driver releases his / her foot from the accelerator pedal, so the accelerator operation amount becomes zero. Then, in the above-described conventional technology, the upper limit value of the fuel supply amount is set to be extremely low, and sufficient engine torque cannot be obtained when traveling uphill, and the engine may stall in the worst case. is there.
[0009]
In recent years, so-called VSC (Vehicle Stability Control) control has been adopted in which vehicle stability is improved by suppressing understeer and oversteer of the vehicle. In this VSC control, the driver is operating a brake (usually at this time). When the accelerator operation amount is 0), the throttle valve may be opened to some extent to increase the engine torque. However, even in this case, in the conventional technique in which the upper limit value of the fuel supply amount is set based on the accelerator operation amount, the upper limit value of the fuel supply amount is set extremely low, and as a result, the engine torque can be increased. Without being able to improve the running stability of the vehicle.
[0010]
As described above, in the technique disclosed in the above publication, various vehicle controls that may adjust the throttle valve to the open side regardless of the amount of accelerator operation (even when the accelerator pedal is not depressed), and driving of the throttle valve Even if an abnormality occurs in the control system, a fail-safe function that does not unnecessarily increase engine torque cannot be achieved.
[0011]
The present invention has been made in view of these problems, and provides a fail-safe function in which the engine torque does not increase unnecessarily even when an abnormality occurs in the drive control system of the throttle valve, and the throttle valve opening is controlled by the amount of accelerator operation. It is an object of the present invention to provide a vehicular engine control device that can reliably achieve control that is adjusted in accordance with vehicle conditions other than the above.
[0012]
[Means for solving the problems and effects of the invention]
In the vehicle engine control apparatus of the present invention made to achieve the above object, the target opening setting means normally has a target opening of the throttle valve according to the amount of operation of the accelerator pedal operated by the driver. And the target opening of the throttle valve is set according to the vehicle state other than the operation amount of the accelerator pedal. Then, the drive signal output means outputs a drive signal corresponding to the target opening set by the target opening setting means to the actuator for driving the throttle valve, so that the throttle valve opening becomes the target opening. The target opening set by the setting means is controlled.
[0013]
On the other hand, the fuel supply amount calculating means calculates the fuel supply amount to the engine based on the operating state of the engine including the intake air amount adjusted by the throttle valve, and the upper limit setting means is the fuel supply to the engine. The upper limit value of the supply amount is set to a larger value in accordance with the target opening of the throttle valve set by the target opening setting means as the target opening is set to the open side.
[0014]
When the limiting means compares the fuel supply amount calculated by the fuel supply amount calculating means with the upper limit value set by the upper limit value setting means, and the calculated fuel supply amount exceeds the upper limit value. The fuel supply amount to the engine is limited to the upper limit value, and the fuel supply means supplies the fuel supply amount obtained through the restriction means to the engine.
[0015]
According to such a vehicle engine control apparatus of the present invention, the throttle valve drive control system comprising the actuator for driving the throttle valve and the drive signal output means for outputting a drive signal to the actuator becomes abnormal. Even if the engine opens more than necessary and the intake air amount of the engine increases, the amount of fuel supplied to the engine is limited to the upper limit value according to the target opening of the throttle valve, so the engine torque increases unnecessarily. Can be prevented.
[0016]
Moreover, in the vehicle engine control device of the present invention, when the target opening of the throttle valve is normally set according to the amount of operation of the accelerator pedal, and the driving state of the vehicle is in a predetermined specific state Is set according to the vehicle state other than the amount of operation of the accelerator pedal, but in particular, the upper limit value for limiting the fuel supply amount is set to the open side according to the target opening of the throttle valve. The larger the value is set, the larger the value is set.
[0017]
Therefore, for example, the above-described auto cruise control or VSC control is performed, and the target opening of the throttle valve is set to the open side even though the operation amount of the accelerator pedal is 0 (that is, the accelerator pedal is fully closed). In this case, the upper limit value of the fuel supply amount corresponding to the target opening is set, and an appropriate engine torque can be obtained without causing a shortage of the engine torque as in the prior art described above. it can.
[0018]
Therefore, according to the vehicle engine control apparatus of the present invention, the fail-safe function that the engine torque does not increase unnecessarily even if an abnormality occurs in the drive control system of the throttle valve, and the opening degree of the throttle valve is controlled by the accelerator pedal. Control that adjusts according to the vehicle state other than the operation amount can be made compatible at a high level.
[0019]
Incidentally, since the intake air amount of the engine changes with a delay with respect to the change in the target opening of the throttle valve, for example, when the target opening of the throttle valve changes from fully open to fully closed during VSC control or the like. If the upper limit of the supply amount is suddenly set to the value when the target opening is fully closed, the fuel supply amount will be insufficient with respect to the actual intake air amount, and the engine will misfire. There is a possibility.
[0020]
Therefore, as described in claim 2, when the upper limit value change adjusting means is provided, and the upper limit value change adjusting means at least changes the target opening of the throttle valve set by the target opening setting means to the closed side In addition, if the upper limit value set by the upper limit value setting means and used by the limiting means is gradually changed, the engine of the engine when the target opening of the throttle valve suddenly changes to the closing side as described above. Misfire can be reliably prevented, and a greater effect can be obtained.
[0021]
The upper limit value change adjusting means may always gradually change the upper limit value of the fuel supply amount, but only when the target opening of the throttle valve changes to the closing side, the upper limit value of the fuel supply amount. May be gradually changed (that is, the upper limit value is gradually reduced).
[0022]
In order to prevent engine misfire when the target opening of the throttle valve suddenly changes to the closing side, the target opening of the throttle valve set by the target opening setting means as set forth in claim 3. Limiting operation prohibiting means for prohibiting the restriction of the fuel supply amount by the limiting means when the degree changes to the closing side may be provided.
[0023]
In the configuration provided with such restricting operation prohibiting means, when the target opening degree changes to the closed side, an abnormality occurs in the drive control system of the throttle valve, and the throttle valve opens more than necessary. When the air amount increases, the fuel supply amount increases accordingly, and the engine torque increases. However, when the change of the target opening degree to the closing side is finished, the fuel supply amount is immediately limited and becomes important. It is prevented.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. Needless to say, the embodiments of the present invention are not limited to the following, and can take various forms as long as they belong to the technical scope of the present invention.
[0025]
[First Embodiment]
First, FIG. 1 is a configuration diagram illustrating the vehicle engine control device of the first embodiment together with the entire system of the engine 2. The engine 2 of the present embodiment is a so-called four-cylinder engine having four cylinders, and the vehicle on which the engine 2 is mounted is a so-called rear wheel drive vehicle having rear wheels as drive wheels.
[0026]
As shown in FIG. 1, the engine 2 is provided with an intake passage 4 and an exhaust passage 6, and a throttle valve for adjusting the amount of air taken into the engine 2 (intake air amount) is provided in the intake passage 4. 8 is provided, and an air flow meter 10 for detecting the intake air amount is provided upstream thereof.
[0027]
A motor 12 having a rotor connected to the rotating shaft of the throttle valve 8 via a gear is provided on the outer wall of the intake passage 4. The throttle valve 8 is opened and closed by the motor 12. Further, on the rotating shaft of the throttle valve 8, a return spring 14 for urging the throttle valve 8 in the fully closed direction, a throttle opening sensor 16 for detecting the actual opening (throttle opening) of the throttle valve 8, and Is provided.
[0028]
Further, an electromagnetic fuel injection valve 18 for injecting fuel for each cylinder is provided in the vicinity of the engine 2 in the intake passage 4, and the fuel injection valve 18 and the motor 12 are engine control electronics. It is driven by a control device (hereinafter referred to as engine ECU) 20.
[0029]
The engine ECU 20 is composed mainly of a well-known microcomputer comprising a CPU 20a, ROM 20b, RAM 20c and the like, and outputs a drive signal to each of the motor 12 and the fuel injection valve 18 in response to a command from the microcomputer. It also has a circuit.
[0030]
The engine ECU 20 includes an accelerator opening sensor 24 that detects an accelerator opening that is an operation amount of an accelerator pedal 22 that is depressed by a driver of the vehicle, including the air flow meter 10 and the throttle opening sensor 16. The engine 2 includes a rotation speed sensor 26 that detects the rotation speed of the engine 2 (engine rotation speed), a water temperature sensor 28 that detects the cooling water temperature of the engine 2, and an air-fuel ratio sensor 30 that detects the concentration of oxygen remaining in the exhaust gas. Sensor signals from various sensors for detecting the driving state are input. The engine ECU 20 also receives a signal from a vehicle speed setting switch 32 for so-called auto-cruise control that causes the vehicle to travel at a constant speed set by the driver.
[0031]
Further, the engine ECU 20 includes a VSC control electronic control device (hereinafter referred to as VSC / ECU) 34 that performs so-called VSC control that suppresses understeer and oversteer of the vehicle to improve running stability, and an automatic transmission 36. A transmission control electronic control unit (hereinafter referred to as ECT / ECU) 38 for performing the shift control is connected via a communication line 40. The VSC / ECU 34 and the ECT / ECU 38 are also configured with a known microcomputer as a main part, like the engine ECU 20.
[0032]
Here, the engine ECU 20, the VSC / ECU 34, and the ECT / ECU 38 are configured to share the sensor signal input to each of them and the control information calculated by each of them by performing serial communication via the communication line 40. Has been.
The VSC / ECU 34 detects the turning state of the vehicle based on sensor signals from the lateral acceleration sensor 44 that detects the lateral acceleration of the vehicle, the wheel speed sensor 46 provided on each wheel, and the detected turning state. Accordingly, the brake device (not shown) of each wheel is controlled in response to this, and the target opening of the throttle valve 8 for performing VSC control (hereinafter referred to as target opening by VSC control) is transmitted to the engine ECU 20. Then, the engine ECU 20 controls the opening degree of the throttle valve 8.
[0033]
For example, when the vehicle is in an oversteer tendency, the vehicle posture is stabilized by braking one of the left and right wheels, and when understeer occurs during braking by the driver, the throttle valve 8 is opened and the engine is opened. The vehicle posture is stabilized by increasing the torque. Furthermore, the throttle valve 8 may be forcibly closed when the amount of operation (accelerator opening) of the accelerator pedal 22 by the driver is too large and power oversteer occurs.
[0034]
On the other hand, the ECT / ECU 38 receives signals from the shift switch 48 provided on the shift lever and information acquired from other ECUs 20 and 34 by serial communication (mainly the accelerator opening from the engine ECU 20 and the VSC / ECU 34). In accordance with the vehicle speed calculated based on the signal from the wheel speed sensor 46, the gear of the automatic transmission 36 is controlled, and the target opening of the throttle valve 8 (hereinafter referred to as the throttle valve 8) for performing automatic transmission control to the engine ECU 20 , The target opening by ECT control) is transmitted, and the engine ECU 20 controls the opening of the throttle valve 8.
[0035]
For example, the automatic transmission 36 is shifted down when the driver releases the accelerator pedal. At this time, the throttle valve 8 is opened to increase the engine torque so that sudden engine braking does not work. Further, in order to protect the automatic transmission 36, the throttle valve 8 may be closed.
[0036]
The engine ECU 20 drives the motor 12 so that the throttle opening detected by the throttle opening sensor 16 becomes the target opening of the throttle valve 8 set internally. The target opening degree of the throttle valve 8 is set according to the accelerator opening degree detected by the opening degree sensor 24, and the vehicle speed setting switch 32 is set when the vehicle is traveling at a predetermined speed (for example, 60 km / h) or more. When the button is pressed, the vehicle speed at that time is stored, and auto-cruise control is performed in which the target opening of the throttle valve 8 is set so that the actual vehicle speed becomes the stored vehicle speed. In the following description, the target opening of the throttle valve 8 set according to the accelerator opening is referred to as the target opening based on the accelerator opening, and the target of the throttle valve 8 set for auto-cruise control. The opening is referred to as a target opening by cruise control.
[0037]
Furthermore, when the engine ECU 20 receives the target opening degree by the VSC control from the VSC / ECU 34 or the target opening degree by the ECT control from the ECT / ECU 38, the engine ECU 20 sets the received opening degree to the accelerator opening degree. Is used for driving the motor 12 with priority over the target opening based on the above and the target opening by cruise control.
[0038]
On the other hand, the engine ECU 20 starts the intake air amount of the engine 2 detected by the air flow meter 10, the engine rotational speed detected by the rotational speed sensor 26, the cooling water temperature detected by the water temperature sensor 28, and the air-fuel ratio sensor 30. Based on the oxygen concentration in the exhaust gas detected by the above, a fuel injection amount as a fuel supply amount to the engine 2 is calculated, and the fuel injection valve 18 is driven according to the calculated fuel injection amount. By driving the fuel injection valve 18 in this way, fuel corresponding to the calculated fuel injection amount is supplied to the engine 2.
[0039]
Then, next, processing unique to the first embodiment, which is executed by the engine ECU 20 to drive the motor 12 (throttle valve 8) and the fuel injection valve 18, will be described with reference to the flowchart shown in FIG. Note that the process of FIG. 3 is repeatedly executed at predetermined time intervals (for example, 8 ms).
[0040]
As shown in FIG. 3, when the engine ECU 20 starts executing the processing, in a first step (hereinafter simply referred to as “S”) 110, the target opening degree of the throttle valve 8 used to drive the motor 12. Is set according to the following procedure.
First, a target opening based on the accelerator opening is obtained according to the accelerator opening detected by the accelerator opening sensor 24. Note that the target opening based on the accelerator opening is obtained by referring to a data map in the ROM 20b indicating the relationship between the accelerator opening and the target opening of the throttle valve 8.
[0041]
Further, at the time of auto-cruise control, the target opening degree by cruise control is set so that the actual vehicle speed calculated by the VSC / ECU 34 based on the signal from the wheel speed sensor 46 becomes the vehicle speed set by operating the vehicle speed setting switch 32. Ask for.
When the target opening by the VSC control from the VSC / ECU 34 and the target opening by the ECT control from the ECT / ECU 38 are not received, that is, the opening adjustment of the throttle valve 8 by the VSC control and the automatic transmission control. In the case where the throttle valve 8 is not adjusted by driving, the motor 12 is driven with the larger one of the target opening based on the obtained accelerator opening and the target opening by cruise control. It is set as the target opening used for
[0042]
Further, when the target opening by ECT control is received from the ECT / ECU 38, the target opening by the received ECT control is given priority over the target opening by the accelerator opening and the target opening by cruise control. The opening degree is set as a target opening degree used for driving the motor 12.
[0043]
Furthermore, when the target opening degree by the VSC control is received from the VSC / ECU 34, the target opening degree based on the accelerator opening degree, the target opening degree by the cruise control, and the target opening degree by the ECT control are all determined. Also, the received target opening degree by the VSC control is set as a target opening degree used for driving the motor 12.
[0044]
That is, the priority of the target opening actually used for driving the motor 12 is the highest priority on the target opening based on the VSC control, and then the priority on the target opening based on the ECT control is given priority. When the opening degree of the throttle valve 8 is not adjusted by the transmission control, the larger opening degree is given priority between the target opening degree based on the accelerator opening degree and the target opening degree based on the cruise control.
[0045]
Although not shown, the engine ECU 20 executes a motor drive process for driving the motor 12 every predetermined time in parallel with the process of FIG. 3, and the throttle valve set in S110 above is executed. The target opening of 8 is referred to in the motor driving process. Then, by executing this motor driving process, a drive signal is output to the motor 12 so that the throttle opening detected by the throttle opening sensor 16 becomes the target opening set in S110.
[0046]
In this embodiment, the VSC / ECU 34 calculates the actual vehicle speed based on the signal from the wheel speed sensor 46, and the engine ECU 20 and the ECT / ECU 38 obtain the vehicle speed from the VSC / ECU 34 by serial communication. However, the wheel speed sensor 46 or another vehicle speed sensor for detecting the vehicle speed may be input to the engine ECU 20 and the ECT / ECU 38, respectively, and the engine ECU 20 and the ECT / ECU 38 may detect the vehicle speed by themselves. .
[0047]
Next, after setting the target opening of the throttle valve 8 as described above in S110, in the following S120, from the target opening set in S110, using a data map stored in advance in the ROM 20b as shown in FIG. The maximum injection amount as the upper limit value of the fuel supply amount is obtained. The data map of FIG. 2 shows the relationship between the target opening of the throttle valve 8 and the maximum injection amount, and the maximum injection amount becomes larger as the target opening is set to the open side. It is set up. FIG. 2 shows an image of the data map. The actual data map is stored as binary data in the ROM 20b.
[0048]
When the maximum injection amount is obtained in this way, in subsequent S130, sensor signals from various sensors 26, 28, 30 including the air flow meter 10 are taken in, and the operating state of the engine 2 such as the intake air amount is detected. . In subsequent S140, the fuel injection amount to the engine 2 is calculated based on the operating state such as the intake air amount detected in S130.
[0049]
In subsequent S150, the fuel injection amount obtained in S140 is compared with the maximum injection amount obtained in S120. If the fuel injection amount is larger than the maximum injection amount, the process proceeds to S160 and obtained in S120. The maximum injection amount is set as the fuel injection amount used to drive the fuel injection valve 18, and then the processing ends.
[0050]
In S150, when it is determined that the fuel injection amount obtained in S140 is not larger than the maximum injection amount, the process is terminated as it is, so that the fuel injection amount obtained in S140 becomes the fuel injection valve 18. Is set as the fuel injection amount used to drive the.
[0051]
Although not shown, the engine ECU 20 executes an injection valve drive process for driving the fuel injection valve 18 in parallel with the process of FIG. 3 and in synchronization with the rotation of the engine 2. The fuel injection amount set as the fuel injection amount used for driving the fuel injection valve 18 as described above is referred to in the injection valve drive processing. By executing this injection valve driving process, the fuel injection valve 18 is opened for a time corresponding to the set fuel injection amount, and fuel is supplied to the engine 2.
[0052]
In the first embodiment, the motor 12 corresponds to an actuator, and the VSC / ECU 34 performs processing for obtaining the target opening by VSC control and the ECT / ECU 38 for obtaining the target opening by ECT control. The process to be performed and the process of S110 correspond to the target opening setting means, and the drive circuit provided for outputting the drive signal to the motor 12 in the engine ECU 20 and the motor drive process described above are the drive signal output. The processing of S130 and S140 corresponds to the fuel supply amount calculation means, the processing of S120 corresponds to the upper limit value setting means, the processing of S150 and S160 corresponds to the limiting means, the fuel injection valve 18, The above-described injection valve driving process corresponds to the fuel supply means.
[0053]
As described above in detail, in the vehicle engine control apparatus according to the first embodiment, as shown in FIG. 4, the cruise obtained according to the target opening based on the accelerator opening and the vehicle state other than the accelerator opening. Any one of the target opening by control, the target opening by VSC control, and the target opening by ECT control is selected and set as the target opening of the throttle valve 8 used to drive the motor 12. ing.
[0054]
That is, at the normal time when the throttle valve 8 is not adjusted by auto-cruise control, VSC control, and automatic transmission control, the target opening based on the accelerator opening is set as the target opening of the throttle valve 8, and cruise When the target opening by cruise control is larger than the target opening based on the accelerator opening at the time of control, the opening of the throttle valve 8 is adjusted by VSC control because the vehicle tends to understeer or oversteer when the vehicle turns. In this case, or when adjusting the opening of the throttle valve 8 in accordance with the shift control of the automatic transmission 36, the target opening by the cruise control, the target opening by the VSC control, and the ECT control regardless of the accelerator opening Any one of the target openings is set as the target opening of the throttle valve 8.
[0055]
Then, the maximum injection amount for limiting the fuel injection amount is set to a larger value as the target opening is set to the open side according to the target opening of the throttle valve 8 set as described above. The fuel injection amount obtained according to the operating state of the engine 2 such as the intake air amount is limited to the maximum injection amount.
[0056]
According to the vehicle engine control apparatus of the first embodiment as described above, the drive control system of the throttle valve 8 including the motor 12 that drives the throttle valve 8 and the drive circuit that outputs a drive signal to the motor 12 becomes abnormal. Thus, even if the throttle valve 8 opens more than necessary and the intake air amount of the engine 2 increases, the fuel injection amount to the engine 2 is limited to the maximum injection amount according to the target opening of the throttle valve 8. It is possible to prevent the engine torque from increasing unnecessarily.
[0057]
Moreover, in the vehicle engine control apparatus of the first embodiment, the maximum injection amount for limiting the fuel injection amount is set according to the target opening of the throttle valve 8.
Therefore, auto-cruise control, VSC control, and automatic transmission control are performed, and the target opening of the throttle valve 8 is opened despite the accelerator opening being 0 (that is, the accelerator pedal 22 is fully closed). Even when set to the side, the maximum fuel injection amount corresponding to the target opening is set and an appropriate fuel injection amount is secured, and the engine torque is insufficient as in the prior art disclosed in the aforementioned publication. Therefore, an appropriate engine torque can be obtained.
[0058]
Therefore, according to the vehicle engine control apparatus of the first embodiment, the fail-safe function that the engine torque does not increase unnecessarily even if an abnormality occurs in the drive control system of the throttle valve 8, and the throttle valve 8 is opened. The auto cruise control, the VSC control, and the automatic transmission control that adjust the degree according to the vehicle state other than the accelerator opening can be achieved at a high level.
[0059]
[Second Embodiment]
Incidentally, since the intake air amount of the engine 2 changes with a delay with respect to the change in the target opening of the throttle valve 8, for example, when the target opening of the throttle valve 8 changes from fully open to fully closed during VSC control. When the maximum injection amount, which is the upper limit value of the fuel injection amount, is suddenly set to the value when the target opening is fully closed, the fuel injection amount becomes insufficient with respect to the actual intake air amount, There is a possibility that the engine 2 may misfire.
[0060]
Therefore, if configured as in the second embodiment described below, misfire of the engine 2 when the target opening of the throttle valve 8 suddenly changes to the closing side can be reliably prevented.
The vehicle engine control apparatus of the second embodiment differs from the first embodiment only in that the process shown in FIG. 5 is executed by the engine ECU 20. Note that the process of FIG. 5 is executed in place of the process of FIG.
[0061]
That is, when the engine ECU 20 starts executing the process of FIG. 5, first, in S210, the target opening of the throttle valve 8 used to drive the motor 12 is set in the same procedure as S110 of FIG. Then, in the subsequent S220, as in S120 of FIG. 3, the maximum injection amount is obtained from the target opening set in S210 using the data map shown in FIG. 2, but in the second embodiment, The obtained maximum injection amount is set as a temporary maximum injection amount tFMAX.
[0062]
In S225, the maximum injection amount FMAXn that is actually used to limit the fuel injection amount in the current process is obtained from the provisional maximum injection amount tFMAX set in S220 using the following equation 1. In Equation 1, “α” is a constant preset to a value from 0 to 1, and “FMAX n-1” is the maximum injection amount obtained in the previous S225.
[0063]
[Expression 1]
FMAXn = (1-α) × FMAXn−1 + α × tFMAX (Formula 1)
When the maximum injection amount FMAXn is determined in this way, in the following S230, the operating state of the engine 2 is detected in the same procedure as S130 in FIG. 3, and in the subsequent S240, the same as S140 in FIG. The fuel injection amount to the engine 2 is calculated based on the operating state such as the intake air amount detected in S230.
[0064]
Then, in subsequent S250 and S260, processing for limiting the fuel injection amount is performed in the same manner as in S150 and S160 of FIG.
Specifically, in S250, the fuel injection amount obtained in S240 is compared with the maximum injection amount FMAXn obtained in S225. If the fuel injection amount is larger than the maximum injection amount FMAXn, in subsequent S260, The maximum injection amount FMAXn obtained in S225 is set as the fuel injection amount used to drive the fuel injection valve 18, and then the processing ends. If it is determined in S250 that the fuel injection amount obtained in S240 is not larger than the maximum injection amount FMAXn, the process is terminated as it is, and the fuel injection amount obtained in S240 is thereby changed to the fuel injection valve. 18 is set as the fuel injection amount used to drive the motor 18.
[0065]
That is, in the second embodiment, the above formula 1 is applied to the latest maximum injection amount tFMAX obtained according to the target opening of the throttle valve 8 and is actually used to limit the fuel injection amount. By obtaining the maximum injection amount FMAXn, the influence on the actual maximum injection amount FMAXn when the maximum injection amount tFMAX is changed is suppressed. In other words, the actual maximum injection amount FMAXn is set by smoothing the maximum injection amount tFMAX.
[0066]
According to the vehicular engine control apparatus of the second embodiment, even when the target opening of the throttle valve 8 suddenly changes to the closing side during VSC control or the like, the maximum injection amount FMAXn changes gently ( As a result, the misfire of the engine 2 is ensured when the target opening of the throttle valve 8 suddenly changes to the closing side. Can be prevented, and a greater effect can be obtained.
[0067]
In the second embodiment, the process of S225 in FIG. 5 corresponds to the upper limit change adjusting means.
In the second embodiment, the maximum injection amount FMAXn is always gradually changed. However, only when the target opening degree of the throttle valve 8 is changed to the closing side, the process of S225 is executed to obtain the maximum value. The injection amount FMAXn may be gradually changed (that is, gradually decreased).
[0068]
[Third Embodiment]
On the other hand, in order to prevent misfire of the engine 2 when the target opening of the throttle valve 8 suddenly changes to the closing side, a third embodiment described below may be used.
The vehicle engine control apparatus of the third embodiment is different from the first embodiment only in that the process shown in FIG. 6 is executed by the engine ECU 20. Note that the process of FIG. 6 is executed in place of the process of FIG. 3, and this process is also repeatedly executed at predetermined time intervals (for example, 8 ms). In FIG. 6, the same processing contents as those in FIG. 3 are denoted by the same step numbers, and detailed description thereof is omitted.
[0069]
That is, as shown in FIG. 6, in the process executed by the engine ECU 20 of the third embodiment, after obtaining the fuel injection amount in S140, in the subsequent additional S145, the throttle valve 8 set in S110 is set. It is determined whether or not the target opening degree has changed to the closing side, and when the target opening degree has changed to the closing side, the process is performed as it is without performing the processing for limiting the fuel injection amount in S150 and S160. The process 6 is terminated.
[0070]
Even with the vehicular engine control apparatus according to the third embodiment, when the target opening of the throttle valve 8 suddenly changes to the closed side during VSC control, the fuel for the actual intake air amount is obtained. It is possible to prevent the injection amount from becoming insufficient, and as a result, misfire of the engine 2 can be prevented.
[0071]
In the third embodiment, the process of S145 in FIG. 6 corresponds to the restricting operation prohibiting unit.
[Brief description of the drawings]
FIG. 1 is a configuration diagram illustrating an entire system configuration according to a first embodiment.
FIG. 2 is an explanatory diagram illustrating a data map for setting a maximum fuel injection amount according to a throttle valve target opening.
FIG. 3 is a flowchart showing a process executed by the engine ECU of FIG.
FIG. 4 is an explanatory diagram showing a procedure for setting a throttle valve target opening.
FIG. 5 is a flowchart showing a process executed by an engine ECU of a second embodiment.
FIG. 6 is a flowchart showing a process executed by an engine ECU of a third embodiment.
[Explanation of symbols]
2 ... Engine 4 ... Intake passage 6 ... Exhaust passage 8 ... Throttle valve
10 ... Air flow meter 12 ... Motor 14 ... Return spring
16 ... Throttle opening sensor 18 ... Fuel injection valve
20 ... Electronic control unit for engine control (engine ECU) 20a ... CPU
20b ... ROM 20c ... RAM 22 ... Accelerator pedal
24 ... Accelerator opening sensor 26 ... Rotation speed sensor 28 ... Water temperature sensor
30 ... Air-fuel ratio sensor 32 ... Vehicle speed setting switch
34 ... Electronic control unit for VSC control (VSC / ECU) 36 ... Automatic transmission
38 ... Electronic control unit for transmission control (ECT / ECU) 40 ... Communication line
44 ... Lateral acceleration sensor 46 ... Wheel speed sensor 48 ... Shift switch

Claims (3)

A throttle valve for adjusting the intake air amount of an engine mounted on the vehicle;
An actuator for driving the throttle valve;
In normal times, the target opening of the throttle valve is set according to the amount of operation of the accelerator pedal operated by the driver, and when the driving state of the vehicle becomes a predetermined specific state, A target opening setting means for setting a target opening of the throttle valve according to a vehicle state other than an operation amount of an accelerator pedal;
Drive signal output means for outputting a drive signal corresponding to the target opening set by the target opening setting means to the actuator;
Fuel supply amount calculation means for calculating a fuel supply amount to the engine based on at least an operating state of the engine including the intake air amount;
The upper limit value that sets the upper limit value of the fuel supply amount to the engine to a larger value as the target opening degree is set to the open side according to the target opening degree set by the target opening degree setting means Setting means;
When the fuel supply amount calculated by the fuel supply amount calculation means is compared with the upper limit value set by the upper limit value setting means, and the calculated fuel supply amount exceeds the upper limit value, Limiting means for limiting the fuel supply amount to the upper limit;
Fuel supply means for supplying the engine with the fuel supply amount determined through the limiting means;
A vehicle engine control apparatus comprising: The vehicle engine control device according to claim 1,
At least when the target opening of the throttle valve set by the target opening setting means changes to the closing side, the upper limit value set by the upper limit setting means and used by the limiting means is changed gently. Provided with an upper limit change adjustment means,
An engine control device for a vehicle. The vehicle engine control device according to claim 1,
When the target opening degree of the throttle valve set by the target opening degree setting means has changed to the closing side, a limiting operation prohibiting means for prohibiting the restriction of the fuel supply amount by the limiting means;
An engine control device for a vehicle.

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