JP3797113B2 - Control device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control device for an internal combustion engine, and more particularly to a control device for an internal combustion engine that controls the engine speed to a target speed during engine idle operation.
[0002]
[Prior art]
A control device that maintains the engine speed at a predetermined target speed during engine idle operation is generally known.
For example, an example of this type of control device is disclosed in Japanese Patent Application Laid-Open No. 5-222997. The device disclosed in the publication keeps the idling engine speed constant by feedback controlling the engine intake air amount so that the engine speed matches a predetermined target engine speed during idling operation, and the engine intake air amount. When a failure occurs in the rotational speed control by the control, the idle rotational speed is kept constant by feedback control of the ignition timing.
[0003]
[Problems to be solved by the invention]
However, when the engine is started, particularly when the engine is cold started, combustion is likely to deteriorate, and the engine speed may become unstable.
For example, in an engine equipped with a fuel injection valve that injects fuel into the engine intake port, the injected fuel adheres to the intake port wall surface as a liquid without being vaporized due to the low temperature at the cold start of the engine. The concentration may be insufficient. In particular, when low-volatile fuel (heavy fuel) is used, fuel vaporization becomes insufficient during engine cold start, and the amount of vaporized fuel actually sucked into the cylinder decreases. Combustion is likely to deteriorate due to lean air-fuel ratio of the air-fuel mixture in the cylinder. In such a case, if the rotational speed control based on the intake air amount is performed as in the device disclosed in Japanese Patent Laid-Open No. Hei 5-222997, the degree of deterioration of combustion increases, and the rotational speed control based on the intake air amount is abnormal. Even if it does not occur, the engine speed may become more unstable.
[0004]
That is, when the engine speed is decreased due to the deterioration of combustion in the rotational speed control based on the intake air amount, an operation for increasing the throttle valve opening is performed in order to increase the intake air amount and increase the rotational speed. However, if the throttle valve opening is increased with insufficient fuel vaporization, the intake pipe negative pressure on the downstream side of the throttle valve decreases (absolute pressure increases), so the fuel adhering to the intake port wall surface is further vaporized. The air-fuel ratio of the air-fuel mixture becomes leaner and the deterioration of combustion is amplified.
In order to solve the above problem, the applicant of the present application has already disclosed Japanese Patent Laid-Open No. 2000-291467 that controls the idling engine speed during cold by adjusting the throttle valve opening (engine intake air amount) and engine combustion. In the case where deterioration occurs, a control device is proposed in which the rotational speed control by adjusting the throttle valve opening is stopped and switched to rotational speed control by adjusting the engine ignition timing.
[0005]
In the apparatus of the publication, the deterioration of the engine combustion state is judged based on the peak rotational speed at the time of starting the engine, the rotational fluctuation, etc., and when the deterioration has occurred, the rotational speed control by adjusting the throttle valve opening is stopped, By switching to engine speed control by adjusting the engine ignition timing, it is possible to maintain the engine speed at the target engine speed even when the combustion deteriorates.
However, in the internal combustion engine for a vehicle, when the engine speed is controlled by adjusting the engine ignition timing during idle operation after the engine is started, there is no problem when the vehicle is stopped, but there may be a problem when the vehicle starts running.
[0006]
For example, in a vehicle equipped with an automatic transmission, even if the engine is in an idling state (that is, a state where the driver does not depress the accelerator pedal), if the selector lever is set to the drive range, the vehicle is not depressed unless the brake pedal is depressed. The so-called creep running occurs. In this case, when the ignition timing rotation speed control is performed, the engine rotation speed is maintained at the set rotation speed. Therefore, the engine rotation speed becomes higher than when the rotation speed control is not performed, and the driver is The vehicle traveling speed may increase without intention.
Further, during creep travel during ignition timing rotation speed control, the engine ignition timing is often corrected to the advance side in order to prevent a decrease in engine rotation speed due to travel load. For this reason, for example, when the driver depresses the accelerator pedal to start running from this state and the engine load increases, the ignition timing is advanced more than the normal start operation and knocking occurs. There is a case.
[0007]
The above is not a problem peculiar to vehicles equipped with automatic transmissions. Even in vehicles equipped with manual transmissions, the creeping of the vehicle starts when the clutch is gradually connected without the driver depressing the accelerator pedal. A similar problem arises because of
The above problem can be solved for the time being by stopping the rotational speed control based on the ignition timing immediately when creep driving is started or when the driver starts the vehicle and returning the ignition timing to the basic ignition timing determined from the engine operating state. . However, when the engine is cold, the ignition timing correction amount by the ignition timing rotation speed control may be considerably large. For this reason, if the ignition timing is immediately returned to the basic ignition timing when the creep running is started, the engine rotational speed decreases due to the traveling load, and the engine may stall due to the decrease in the rotational speed. Also, for example, if the ignition timing has been significantly corrected to the retarded side, if the engine ignition timing is immediately returned to the basic ignition timing when the driver starts the vehicle, the driver will exceed the intention of the driver. There is a possibility that an increase in torque occurs and the vehicle suddenly starts unintended by the driver.
[0008]
In view of the above problems, the present invention causes the driver to feel uncomfortable or prevent the start operation when the vehicle starts running while the ignition timing rotation speed control is performed during engine cold idle operation. It is another object of the present invention to provide a control device for an internal combustion engine that can stop the ignition timing rotation speed control and shift the engine ignition timing to the basic ignition timing.
[0009]
[Means for Solving the Problems]
According to the first aspect of the present invention, when a predetermined condition during the engine cold idle operation is satisfied, the engine ignition timing correction amount is calculated according to the engine speed, and is determined based on the engine operating state. A control device for an internal combustion engine for a vehicle that controls an engine speed to a predetermined target speed by performing ignition timing speed control for correcting a basic ignition timing using the correction amount, wherein the ignition timing speed When the vehicle starts creep running during execution of the number control, the ignition timing rotation speed control is stopped and the correction amount at the start of creep running is stored, and stored after the creep driving starts regardless of the engine speed. A control device for an internal combustion engine is provided that corrects the basic ignition timing using the correction amount.
[0010]
That is, according to the first aspect of the present invention, when the vehicle starts creep running during execution of the ignition timing rotational speed control, the ignition timing correction based on the engine rotational speed is stopped and the correction amount is set to the value at the start of creep traveling. Fix it. For this reason, it is possible to prevent the ignition timing from being advanced excessively at the start of creep travel and causing the traveling speed to be excessive, or being retarded excessively to cause engine stall. In addition, since the ignition timing is corrected using the correction amount in the state when the vehicle is stopped without immediately returning to the basic ignition timing, the ignition timing corresponding to the combustion state of the engine is stored. become.
[0011]
According to the second aspect of the present invention, when a predetermined condition during the engine cold idle operation is satisfied, the engine ignition timing correction amount is calculated according to the engine speed, and is determined based on the engine operating state. A control device for an internal combustion engine for a vehicle that controls an engine speed to a predetermined target speed by performing ignition timing speed control for correcting a basic ignition timing using the correction amount, wherein the ignition timing speed When the vehicle starts creeping during execution of the number control, the engine ignition timing is corrected to the advance side by the ignition timing rotational speed control, and the vehicle creep traveling speed is equal to or higher than a predetermined first predetermined speed. When the ignition timing rotational speed control is stopped, the correction amount when the ignition timing rotational speed control is stopped is gradually reduced to zero while the vehicle creep travel speed is equal to or higher than the first predetermined speed. Close to While performing the damping operation, the basic ignition timing is corrected using the correction amount being attenuated to gradually bring the engine ignition timing closer to the basic ignition timing, and the engine ignition is controlled by the ignition timing rotation speed control. When the timing is corrected to the retard side and the vehicle creep travel speed is equal to or lower than a second predetermined speed that is lower than the first predetermined speed, the ignition timing rotation speed control is stopped, and the vehicle While the creep travel speed is equal to or lower than the second predetermined speed, a basic operation is performed using the correction amount that is being attenuated while performing an attenuation operation that gradually brings the correction amount when the ignition timing rotation speed control is stopped to zero. There is provided a control device for an internal combustion engine that performs a creep travel speed reduction suppressing operation that gradually brings the engine ignition timing closer to the basic ignition timing by correcting the ignition timing.
[0012]
That is, in the invention of claim 2, when the vehicle starts creeping during execution of the ignition timing rotation speed control, the vehicle speed becomes equal to or higher than the first predetermined value in a state where the ignition timing is corrected to the advance side. In such a case, the creep travel speed increase suppression operation is performed to gradually retard the ignition timing and approach the basic ignition timing, so that the creep travel speed is prevented from excessively increasing. In addition, when creep running is started during execution of the ignition timing rotational speed control and the ignition timing is corrected to the retard side, the vehicle speed is gradually reduced to a second predetermined value or less, and the ignition timing is gradually advanced. Since the creep travel speed decrease suppressing operation is performed so as to approach the basic ignition timing, the creep travel speed is prevented from excessively decreasing. For this reason, in the present invention, the creep travel speed is maintained between the first predetermined speed and the second predetermined speed.
In the present invention, as in the first aspect of the invention, the ignition timing rotation speed control is stopped when the vehicle starts creeping, and thereafter, the ignition timing correction amount is held at the value at the time of stop, It is also possible to perform an operation for suppressing an increase or a decrease in the creep traveling speed when the creep traveling speed is equal to or higher than the first predetermined value or equal to or lower than the second predetermined value.
[0013]
According to the third aspect of the present invention, when a predetermined condition during the engine cold idle operation is satisfied, the engine ignition timing correction amount is calculated according to the engine speed, and is determined based on the engine operation state. A control device for an internal combustion engine for a vehicle that controls an engine speed to a predetermined target speed by performing ignition timing speed control for correcting a basic ignition timing using the correction amount, wherein the ignition timing speed When the vehicle starts creep running during execution of the numerical control, the engine temperature at the start of creep running is stored, and after the creep running starts, the engine temperature is equal to or greater than a predetermined range from the engine temperature at the start of creep running. When the engine temperature rises or when the engine temperature becomes equal to or higher than a predetermined temperature, the ignition timing rotation speed control is stopped, and the damping operation that gradually brings the correction amount close to zero While, the control apparatus for an internal combustion engine gradually perform a return operation to approach the basic ignition timing engine ignition timing by correcting the basic ignition timing is provided using the correction amount in attenuation.
[0014]
That is, according to the third aspect of the present invention, when the engine temperature (for example, the engine coolant temperature) rises by a predetermined width during engine creep, or when the engine temperature becomes a predetermined value or more, the combustion state of the engine is improved. Therefore, a return operation is performed to return the ignition timing to the basic ignition timing determined from the operating state of the engine. Thus, it is possible to prevent the occurrence of knocking due to the advance of the ignition timing being maintained despite the improved combustion state. Further, since the return to the basic ignition timing is performed by gradually reducing the correction amount to zero, it is possible to prevent sudden changes in the engine speed and torque shock due to sudden changes in the ignition timing.
The operation of the present invention can be used in combination with the operation of the invention of claim 1 and / or 2.
[0015]
According to the fourth aspect of the present invention, when a predetermined condition during the engine cold idle operation is satisfied, the engine ignition timing correction amount is calculated according to the engine speed, and is determined based on the engine operation state. A control device for an internal combustion engine for a vehicle that controls an engine speed to a predetermined target speed by performing ignition timing speed control for correcting a basic ignition timing using the correction amount, wherein the ignition timing speed The engine timing is stopped when the engine throttle opening exceeds a predetermined value when the vehicle is stopped or creeping during engine speed control, and when the engine timing is stopped. If it is corrected to the advance side, the engine ignition timing is immediately returned to the basic ignition timing, and if it is corrected to the retard side, an attenuation operation is performed to gradually bring the correction amount close to zero. Control apparatus for an internal combustion engine which performs gradual return operation for returning to the basic ignition timing engine ignition timing by correcting the basic ignition timing by using the correction amount in attenuation is provided.
[0016]
That is, according to the fourth aspect of the present invention, when the driver performs a start (or acceleration) operation during execution of the ignition timing rotation speed control and the engine load increases, the ignition timing is returned to the basic ignition timing determined by the engine operating state. Perform the operation. In this case, when the ignition timing is corrected to the advance side by correcting the ignition timing rotation speed, the ignition timing is advanced by the ignition timing rotation speed correction by returning the ignition timing to the basic ignition timing simultaneously with the start of the start operation. In addition to the angle, the occurrence of knocking due to the ignition timing advance by acceleration is prevented. Further, when the ignition timing is corrected to the retard side by the ignition timing rotation speed control, the basic ignition timing is restored by gradually reducing the correction amount to zero. As a result, it is possible to prevent the ignition timing from being rapidly advanced and to generate more torque than intended by the driver during the start operation.
The present invention can also be carried out simultaneously with the invention of claim 1, 2 or 3.
[0017]
According to the fifth aspect of the present invention, when the engine ignition timing is corrected to the advance side at the start of the return operation, the fuel supply amount to the engine is increased by an amount corresponding to the ignition timing correction amount. In addition, the control device for an internal combustion engine according to claim 4 is provided, wherein the increase width after the increase is gradually decreased until the increase width becomes zero.
[0018]
That is, in the invention of claim 5, when the ignition timing is corrected to the advance side in claim 4, the ignition timing is returned to the basic ignition timing and the engine is supplied to the engine by an amount corresponding to the correction amount of the ignition timing. Therefore, the reduction in engine output torque due to the return to the basic ignition timing (retardation of ignition timing) is prevented, and the acceleration performance at the time of starting does not deteriorate. In addition, since the increased fuel supply amount is gradually reduced and then stopped, the fuel supply amount returns to a normal value, and sudden fluctuations in the engine output torque at the time of return are prevented.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a schematic view showing the overall configuration when the present invention is applied to an automobile internal combustion engine. In FIG. 1, 1 is an internal combustion engine body, 2 is a surge tank provided in the intake passage of the engine 1, 2a is an intake manifold that connects the surge tank 2 and the intake port of each cylinder, and 16 is an upstream side of the surge tank 2. A throttle valve 7 disposed in the intake passage is a fuel injection valve that injects pressurized fuel into the intake port of each cylinder of the engine 1.
[0020]
In the present embodiment, the throttle valve 16 is provided with an actuator 16a such as a stepper motor, and a type having an opening corresponding to a control signal input from the ECU 10 described later is used. That is, as the throttle valve 16 of the present embodiment, a so-called electronically controlled throttle valve that can take an opening degree that is independent of the driver's accelerator pedal operation amount is used. The throttle valve 16 is provided with a throttle opening sensor 17 for generating a voltage signal corresponding to the operation amount (opening) of the throttle valve.
[0021]
In FIG. 1, 11 is an exhaust manifold for connecting the exhaust ports of the cylinders to a common collective exhaust pipe 14, 20 is a three-way catalyst disposed in the exhaust pipe 14, and 13 is an exhaust merging portion (three-way catalyst 20) of the exhaust manifold 11. An upstream air-fuel ratio sensor 15 disposed upstream) is a downstream air-fuel ratio sensor disposed in the exhaust pipe 14 downstream of the three-way catalyst 20. The three-way catalyst 20 is configured so that when the inflowing exhaust air-fuel ratio is close to the theoretical air-fuel ratio, HC, CO, NO_XThese three components can be purified simultaneously. The air-fuel ratio sensors 13 and 15 are used for exhaust air-fuel ratio detection when feedback-controlling the fuel injection amount to the engine so that the engine air-fuel ratio becomes a predetermined target air-fuel ratio during normal engine operation.
[0022]
In the present embodiment, an intake pressure sensor 3 for generating a voltage signal corresponding to the intake pressure (absolute pressure) in the surge tank is provided in the surge tank 2 in the intake passage, and the water jacket 8 of the cylinder block of the engine body 1 is also provided. Is provided with a water temperature sensor 9 that generates an electrical signal of an analog voltage corresponding to the temperature of the cooling water.
The output signals of the throttle valve opening sensor 17, the intake pressure sensor 3, the water temperature sensor 9, and the air-fuel ratio sensors 13 and 15 are input to the A / D converter 101 with a built-in multiplexer of the ECU 10 described later.
[0023]
Reference numerals 5 and 6 in FIG. 1 denote crank angle sensors disposed in the vicinity of a cam shaft and a crank shaft (not shown) of the engine 1. The crank angle sensor 5 generates a reference position detection pulse signal every 720 °, for example, in terms of the crank angle, and the crank angle sensor 6 generates a crank angle detection pulse signal every 30 ° of the crank angle. The pulse signals of the crank angle sensors 5 and 6 are supplied to the input / output interface 102 of the ECU 10, and the output of the crank angle sensor 6 is supplied to the interrupt terminal of the CPU 103 of the ECU 10. The ECU 10 calculates the rotational speed (rotational speed) of the engine 1 based on the crank angle pulse signal interval from the crank angle sensor 6 and uses it for various controls.
[0024]
The electronic control unit (ECU) 10 of the engine 1 is configured as, for example, a microcomputer, and when the ROM 104, RAM 105, and main switch are turned off in addition to the A / D converter 101 with built-in multiplexer, the input / output interface 102, and the CPU 103. However, a backup RAM 106, a clock generation circuit 107, and the like that can be stored are provided.
The ECU 10 performs basic control of the engine 1 such as fuel injection amount control and ignition timing control of the engine 1 based on the intake pressure, the throttle valve opening, and the engine speed, and in this embodiment, as described later, Idle speed control is performed to maintain the engine speed at the target speed during operation.
[0025]
In order to perform the above-described control, the ECU 10 performs an A / D conversion routine executed at regular time intervals, an intake pressure (PM) signal from the intake pressure sensor 3, a throttle opening (THA) signal from the throttle opening sensor 17, a water temperature A coolant temperature (THW) signal from the sensor 9 is A / D converted and input. Further, a pulse signal proportional to the vehicle travel speed SPD is input to the ECU 10 from a vehicle travel speed sensor 109 provided on a driven wheel (not shown) of the vehicle. The ECU 10 calculates the vehicle travel speed at regular intervals based on the travel speed pulse signal interval.
The input / output interface 102 of the ECU 10 is connected to the fuel injection valve 7 via a drive circuit 108 to control the fuel injection amount and the injection timing from the fuel injection valve 7.
[0026]
Further, the input / output interface 102 of the ECU 10 is connected to each ignition plug 111 of the engine 1 via the ignition circuit 110 to control the ignition timing of the engine and to the actuator 16a of the throttle valve 16 via the drive circuit 113. The actuator 16a is driven to control the throttle valve 16 opening.
[0027]
Next, idle speed control of this embodiment will be described.
In the present embodiment, the ECU 10 performs idle speed control for maintaining the engine speed at a predetermined target speed during idle operation after engine startup. Normally, at the time of engine start (at the time of cranking start), the fuel injection amount of the engine is corrected according to the intake air temperature (atmosphere temperature) and atmospheric pressure to the basic start-up injection amount determined from the coolant temperature and the engine speed. Set to the added amount. Then, after the cranking is started, it is determined that the engine speed has exceeded a predetermined speed (for example, about 400 rpm) higher than the cranking speed (that is, combustion has started in each cylinder and the engine has reached a complete explosion state). After that, the fuel injection amount is set to an amount obtained by multiplying the basic fuel injection amount according to the engine intake air amount and the engine speed by a predetermined coefficient. The basic fuel injection amount is a fuel injection amount required for maintaining the engine combustion air-fuel ratio at the stoichiometric air-fuel ratio. The predetermined coefficient is for compensating for the fuel adhering to the intake port wall surface at the start of the engine and the deterioration of the fuel vaporization state due to the low temperature. The predetermined coefficient is a value greater than 1 at the time of engine start. The engine combustion air-fuel ratio is set to be richer than the stoichiometric air-fuel ratio.
[0028]
Further, when the engine is started, the temperature of the exhaust purification catalyst (shown by 20 in FIG. 1) disposed in the exhaust passage is low, and the catalyst cannot exhibit the exhaust purification function. Therefore, after the engine is started, it is necessary to raise the catalyst temperature to the activation temperature as soon as possible and to start exhaust purification by the catalyst. For this reason, the engine ignition timing is retarded compared to that during normal operation in order to raise the exhaust temperature and raise the catalyst temperature in a short time during idle operation after engine startup.
[0029]
As described above, the fuel injection amount at the time of starting the engine is appropriately set according to various factors. Therefore, if the engine is normally in a normal state, the engine speed fluctuation due to deterioration of combustion during the idling operation after the engine starts. Is less likely to occur. However, even if the engine is normal, the engine speed may fluctuate due to combustion deterioration during idle operation. For example, if the properties of fuel (gasoline) used in the engine are different, combustion deterioration at the time of starting tends to occur. The fuel injection amount at the time of starting the engine is set based on the use of fuel having standard properties. For this reason, for example, when a fuel having a low volatility (heavy fuel) compared to a standard fuel is used for an engine, combustion may be deteriorated particularly at the time of cold start of the engine. That is, since the heavy fuel has low volatility, even when the same amount of fuel as the standard fuel is injected, the ratio of the fuel adhering to the wall surface of the intake port without being vaporized increases and is actually supplied into the cylinder. The amount of fuel that can be reduced. For this reason, the combustion air-fuel ratio of the engine shifts to a leaner side than usual, and the engine rotational speed becomes unstable due to deterioration of combustion.
[0030]
In general, as a method of preventing instability of the engine speed during idling and maintaining the engine speed at a predetermined target speed, feedback control of the engine intake air amount based on the engine speed (intake air speed) Control). In the intake air amount speed control, when the engine speed is lower than the target speed, the throttle valve 16 opening is increased (the engine intake air amount is increased) to increase the speed, and the speed is higher than the target speed. In this case, the rotational speed is maintained at the target rotational speed by performing feedback control based on the rotational speed, which reduces the rotational speed by reducing the throttle valve opening (reducing the intake air amount). However, when heavy fuel is used, the deterioration of combustion of the engine cannot be suppressed by the intake air amount rotational speed control, and the idle rotational speed may not be maintained at the target rotational speed.
[0031]
For example, if heavy combustion fuel is used and the combustion air-fuel ratio of the engine becomes a lean air-fuel ratio and the combustion deteriorates when the engine is started, the intake air speed control increases the engine speed when the engine speed decreases due to combustion deterioration. Therefore, the throttle valve opening is increased. However, when the throttle valve opening is increased, the negative pressure in the intake passage on the downstream side of the throttle valve is reduced (the absolute pressure is increased), so that the injected fuel becomes more difficult to vaporize. For this reason, the engine combustion air-fuel ratio further shifts in the lean direction, resulting in an increase in combustion deterioration.
[0032]
In the present embodiment, when it is determined that the reduction in the engine speed due to the deterioration of the combustion cannot be compensated for by the intake air speed control during the idling engine speed control, the ignition timing engine speed control is performed instead of the intake air engine speed control. Thus, the engine speed is accurately maintained at the target speed even when the combustion deteriorates.
In the ignition timing rotational speed control, an operation for maintaining the engine rotational speed at the target rotational speed by performing feedback control of the ignition timing based on the engine rotational speed during idle operation is performed. However, there is no particular problem even if such ignition timing rotation speed control is performed when the vehicle is stopped, but there is a problem if such ignition timing rotation speed control is performed when the vehicle starts or creeping. There is.
[0033]
For example, when a vehicle creep travels during execution of idle speed control in a vehicle with an automatic transmission or a vehicle with a manual transmission, the vehicle starts to travel without performing the driver's accelerator operation. If the idle speed control by adjusting the ignition timing has been executed, the ignition timing speed control is continued as it is. For this reason, the ignition timing is corrected in the advance direction in order to compensate for the decrease in the engine speed due to the traveling load. For this reason, even if the creep travel is started, the engine speed does not decrease, and the vehicle creep travel speed gradually increases to a speed corresponding to the set idle speed of the engine. For this reason, the traveling speed during creep traveling may increase more than the driver intended.
[0034]
Even when the increase in the creep speed does not occur, when the engine combustion state improves and the idle speed control is stopped during the creep travel, the engine is immediately If the ignition timing is returned to the basic ignition timing, a sudden torque fluctuation due to a change in the ignition timing occurs during traveling of the vehicle, causing a problem that causes the driver to feel uncomfortable.
When the vehicle is started from a stopped state, the engine load increases, so that the normal basic ignition timing is advanced. For this reason, if the start operation of the vehicle is performed from the state where the ignition timing is advanced by the ignition timing rotation speed control, the ignition timing may be excessively advanced and knocking may occur.
[0035]
In order to prevent these problems, the ignition timing rotation speed control should be stopped immediately when the vehicle start operation or creep travel is started. However, even if the creep travel is started, the combustion state of the engine is improved. However, if the ignition timing rotational speed control is stopped immediately at the start of creep travel to prevent the speed from increasing, the engine load may increase due to creep travel and the engine may stall.
[0036]
In the embodiment described below, when a vehicle starting operation or creep running is performed during execution of ignition timing rotation speed control, the ignition timing rotation speed control is smoothly stopped without causing the above-described problems. I have to.
[0037]
Next, an embodiment of the stop operation of the ignition timing rotation speed control at the start of the vehicle or at the start of creep traveling according to the present invention will be described. Before that, the intake air amount rotation in the idle rotation speed control common to the following embodiments is described. The switching operation from the number control to the ignition timing rotation speed control will be described by taking the conventional ignition timing rotation speed control as an example.
FIGS. 2 and 3 are flow charts for explaining the intake air amount rotational speed control operation and the ignition timing rotational speed control operation in the idle rotational speed control, respectively.
In the operation of FIGS. 2 and 3, the intake air amount rotational speed control (FIG. 2) is first performed during engine idle operation, and the intake air amount feedback correction amount, which will be described later, increases due to deterioration of combustion during the intake air amount rotational speed control. When the engine speed reaches a predetermined upper limit, or when the engine speed decreases by a predetermined width or more with respect to the target engine speed, the intake air amount speed control is stopped, and instead the ignition timing speed control (FIG. 3). Is implemented.
[0038]
FIG. 2 is a flowchart for explaining the intake air amount rotational speed control operation. This operation is performed by a routine executed by the ECU 10 at regular intervals.
In the intake air amount rotational speed control operation of FIG. 2, the target idle rotational speed NE is set.₀And the difference DNE (= NE from the current engine speed NE)₀-NE), and the integrated value (integrated value) of DNE and the time change rate DDNE of IDNE and DNE, the value of the intake air amount feedback correction amount EQ becomes EQ = α₁× DNE + α₂× IDNE + α_ThreeX Calculated as DDNE, target intake air quantity Q_TIs increased or decreased according to the correction amount EQ. That is, the engine intake air amount is the target rotational speed NE.₀The proportional integral derivative (PID) control is performed based on the difference DNE between the actual rotational speed NE and the actual rotational speed NE.
[0039]
When the operation shown in FIG. In the present embodiment, when the driver's accelerator pedal operation amount is zero (a state where the driver does not depress the accelerator pedal), it is determined that the engine is currently idling.
When the engine is currently idling in step 201, there is no need for idling engine speed control, so in step 203 the value of an ignition timing engine speed control execution flag IN, which will be described later, is set to 0 and the operation is immediately terminated. The flag IN is a flag indicating whether or not the ignition timing rotation speed control can be executed. When the value of IN is set to 1, the ignition timing rotation speed control (FIG. 3) is executed. The initial value of IN is set to 0.
Therefore, when the engine is not currently idling in step 201, not only the intake amount rotation speed control in step 207 and the subsequent steps but also the ignition timing rotation speed control is not performed. Further, since the value of the intake air amount control execution flag CN, which will be described later, is not changed, the next operation after step 207 is executed if the value of CN is set to 1 when the idle operation is performed next time.
[0040]
If it is determined in step 201 that the engine is currently idling, it is next determined in step 205 whether or not the value of the intake air amount rotational speed control execution flag CN is set to 1. The initial value of the flag CN is set to 1 (execution). As will be described later, the value of the flag CN is determined so that the difference between the target rotational speed and the current rotational speed is the upper limit value DNE at step 219._MAXIf it becomes larger, or the value of the intake air amount feedback correction amount EQ becomes the upper limit EQ in step 221_MAXWhen it becomes larger, it is set to 0 (stop).
If CN ≠ 1 in step 205, this operation is immediately terminated without executing the intake air amount rotational speed control in step 207 and thereafter. If CN = 1, the engine speed NE is read in step 207, and the target speed NE is read in step 209.₀And NE, the integrated value IDNE (integrated value) of the difference DNE is calculated in step 211, and the time change rate DDNE of the difference DNE is calculated in steps 213 and 215, respectively. DNE in step 213_i-1Is the value of DNE at the time of the previous operation execution, and is updated in preparation for the next operation execution at step 215.
[0041]
In step 217, the value of the intake air amount feedback correction amount EQ is determined based on the values of DNE, IDNE, and DDNE.
EQ = α₁× DNE + α₂× IDNE + α_Three× DDNE
Is calculated as α₁, Α₂, Α_ThreeAre a proportional term coefficient, an integral term coefficient, and a derivative term coefficient, respectively, and are positive constant values.
Next, at step 219, the rotational speed difference DNE calculated at step 209 is a predetermined upper limit value DNE._MAX(DNE_MAX> 0), that is, the current engine speed NE is equal to the target engine speed NE.₀It is determined whether or not it has decreased by a predetermined width or more. In step 219, DNE> DNE_MAXIn this case, the engine speed has dropped significantly due to the deterioration of combustion at present, and the engine speed cannot be maintained at the target speed with the intake air speed control, and in the worst case, engine stall occurs. there is a possibility. Therefore, in this case, the process proceeds to step 229 described later, and an operation for stopping the intake air amount rotational speed control and starting the ignition timing rotational speed control is performed. Maximum speed difference DNE_MAXSince it varies depending on the engine type and the like, the details are determined by an experiment using an actual engine.
[0042]
In step 219, DNE ≦ DNE_MAX In other words, if the rotational speed reduction range has not reached the upper limit value, the process proceeds to step 221 where the value of the feedback correction amount EQ calculated in step 217 is equal to the predetermined upper limit value EQ._MAXIt is determined whether or not:
The value of the feedback correction amount EQ increases as the engine combustion deteriorates and the rotational speed decreases, and as the state where the rotational speed decreases continues longer. For this reason, the value of EQ can be used as a parameter representing the degree of deterioration of the engine combustion state. That is, when the value of EQ is larger than a certain level, it is determined that the engine combustion state has deteriorated to the extent that it is difficult to increase the engine speed to the target speed by the intake air speed control. Can do.
[0043]
In the operation of FIG. 2, the value of the feedback correction amount EQ increases, and a predetermined upper limit EQ_MAXIs reached (step 221), it is determined that the deterioration of the combustion state is large and the engine speed cannot be controlled to the target speed by compensating for the deterioration of the combustion by the intake air speed control. In this case, similarly to the case of step 219, step 229 is executed next, and switching from the intake air amount rotational speed control to the ignition timing rotational speed control is performed. EQ_MAXSince it differs depending on the type of engine, it is actually set based on experiments.
In step 219, DNE> DNE_MAXOr EQ> EQ in step 221_MAXIf YES, step 227 is executed, the value of the intake air amount rotational speed control execution flag CN is set to 0, and the value of the ignition timing rotational speed control execution flag IN is set to 1. As a result, when this operation is executed next, the intake air amount rotational speed control in step 207 and the subsequent steps is not executed, and ignition timing rotational speed control (FIG. 3) is executed instead.
[0044]
In step 221, EQ ≦ EQ_MAXIn step 223, the value of the ignition timing rotational speed control execution flag IN is set to 0. In step 225, the target intake air amount Q of the engine is set._TValue is Q_T= Q_CAL+ EQ, and in step 227, the target intake air amount Q_TIs adjusted so that the throttle valve 16 is opened. Q_CALIs the basic intake air amount, and is a value determined by a preset relationship based on the engine speed NE and the throttle valve opening. That is, in this case, the intake air amount rotational speed control is executed, and the ignition timing rotational speed control is not performed.
[0045]
FIG. 3 is a flowchart for explaining a conventional ignition timing rotation speed control operation. The operation of FIG. 3 is performed by a routine executed by the ECU 10 at regular time intervals (or at constant engine crankshaft rotation angles).
In the operation of FIG. 3, first, at step 301, it is determined whether or not the value of the ignition timing rotation speed control execution flag IN is set to 1, and only the operation after step 303 is executed when IN = 1. That is, the ignition timing rotation speed control operation of FIG. 2 is performed only when it is determined that the engine rotation speed cannot be maintained at the target rotation speed by the intake air amount rotation speed control of FIG. 1 (FIG. 2, steps 219 and 221). .
[0046]
Steps 303 to 313 are the same operations as steps 207 to 217 in FIG. That is, also in this operation, the value of the ignition timing feedback correction amount EA is equal to the target rotational speed NE.₀Using the difference DNE between the actual engine speed NE, the integral value IDNE of DNE, and the change rate DDNE (differential value),
EA = β₁× DNE + β₂× IDNE + β_Three× DDNE
As determined by proportional integral derivative (PID) control. β₁, Β₂, Β_ThreeAre a proportional term coefficient, an integral term coefficient, and a derivative term coefficient, respectively, and are positive constant values.
Here, the value of the ignition timing feedback correction amount EA can be used as a parameter representing the degree of deterioration of combustion, similarly to the value of the intake air amount feedback correction amount EQ.
[0047]
After calculating the ignition timing feedback correction amount EA in step 313, in step 315, the engine ignition timing AOP (represented by the crank angle to the compression top dead center of each cylinder) is AOP = EA._CALCalculated as + EA-EACAT. In step 317, the AOP value calculated as described above is set in the ignition circuit 110, and the operation ends. EA_CALIs a basic ignition timing determined by a relationship set in advance according to the engine load state (the intake pressure detected by the intake pressure sensor 3 and the engine speed). Further, EACAT is an ignition timing retard amount for warming up the catalyst, and is a value that changes from a predetermined value to 0 after a predetermined time has elapsed after the start of the engine start operation. EA_CALAnd EACAT are values determined from the operating state of the engine regardless of the ignition timing rotational speed control. Therefore, in the following description, AOP = EA_CAL+ EA-EACAT on the right side of (EA_CALThe value of -EACAT) will be referred to as basic ignition timing for convenience.
[0048]
If IN ≠ 1 in step 301, the ignition timing feedback correction amount EA is set to 0 in step 319, and then step 315 is executed. That is, when the ignition timing rotation speed control is not executed (when the intake air amount rotation speed control of FIG. 2 is executed), the ignition timing AOP is AOP = EA._CAL-Set as EACAT.
[0049]
2 and 3, when it is determined that the engine combustion state deteriorates and the engine speed cannot be controlled to the target engine speed only by the intake air quantity engine speed control of FIG. 2, the ignition timing engine speed of FIG. Control is performed and the rotational speed is maintained at the target rotational speed. However, as described above, if the vehicle creep travel or the start operation is performed during the ignition timing rotation speed control, problems such as an increase in the creep travel speed and occurrence of knocking at the time of start occur. In addition, if the ignition timing rotation speed control is immediately stopped to prevent this problem, problems such as engine stall or uncomfortable feeling to the driver arise.
[0050]
Therefore, in each embodiment described below, even when creep running or starting operation is performed during ignition timing rotation speed control, the driver does not feel uncomfortable or engine stall occurs. An operation to smoothly stop the ignition timing rotation speed control is performed.
Hereinafter, some embodiments of the ignition timing rotation speed control operation of the present invention will be described.
[0051]
(1) First embodiment
In the present embodiment, when the vehicle starts creeping while the ignition timing rotational speed control is being executed (vehicle traveling in a state where the driver does not step on the accelerator pedal), the ignition timing rotational speed control is stopped. After the start of travel, the value of the ignition timing feedback correction amount EA is fixed to the value at the start of travel. As a result, the ignition timing is further advanced during creep travel, and knocking and travel speed are prevented from increasing. In addition, the ignition timing rotational speed control is substantially stopped after the start of travel, but the ignition timing is corrected using the feedback correction amount at the start of creep travel, so that the engine may stall due to deterioration of the combustion state. Is prevented.
[0052]
FIG. 4 is a flowchart for explaining the ignition timing rotation speed control operation of the present embodiment. In the present embodiment, the operation of FIG. 4 is performed at regular intervals by the ECU 10 instead of the ignition timing rotation speed control operation of FIG.
In FIG. 4, in step 401, it is determined based on the value of the flag IN whether or not the ignition timing rotational speed control is currently being executed. If the ignition timing rotational speed control is not being executed, that is, if IN ≠ 1, As in the conventional control of FIG. 3, the value of the ignition timing feedback correction amount EA is set to 0 (step 405).
[0053]
On the other hand, if the ignition timing rotation speed control is currently being executed in step 401, the current vehicle travel speed SPD detected by the vehicle travel speed sensor 109 in step 403 is the predetermined value A.₁It is determined whether or not this is the case. Predetermined value A₁Is a relatively small speed at which it can be determined that the vehicle has started creeping (eg, A₁(Approx. 3 Km / H speed).
[0054]
SPD <A₁If so, since the vehicle is currently stopped (that is, creep running has not started), the ignition timing feedback correction amount EA is calculated based on the idle speed in steps 407 to 411. That is, in step 407, the engine speed NE is read, and in step 409, the deviation DNE (= NE is used using the idle set speed NE0 and NE.₀-NE), and the integrated value (integrated value) IDNE and DNE of time change rate DDNE and DNE are calculated. In step 411, the feedback correction amount EA is EA = β.₁× DNE + β₂× IDNE + β_Three* Calculated as DDNE. The operations in steps 407 to 411 are the same as the operations in steps 303 to 313 in FIG.
[0055]
In step 413 of FIG. 4, the engine ignition timing AOP is set to AOP = EA using the correction amount EA._CALCalculated as + EA−EACAT, and the calculated ignition timing AOP is set in the ignition circuit 110 in step 415. The operations in steps 413 and 415 are the same as those in steps 315 and 317 in FIG.
Thereby, the same ignition timing rotation speed control as that in FIG. 3 is executed when the vehicle is stopped.
On the other hand, at step 403, SPD ≧ A₁If it is, it is determined that creep driving is being performed because the vehicle is currently idling (ie, the driver is not operating the accelerator pedal) and the vehicle has started to travel. . In this case, steps 407 to 411 are not executed, and step 413 is immediately executed. In this embodiment, since the value of the ignition timing feedback correction amount EA is always calculated in steps 407 to 411 during execution of the ignition timing rotation speed control, if step 413 is executed directly after step 403, step 413 is executed. The value of the feedback correction amount EA used in 413 is a value calculated at the time of executing 411 from the previous step 407 (that is, a value at the time when the vehicle starts creeping). Therefore, when the vehicle creep travel is started in step 403, the value of the feedback correction amount EA is fixed to the value at the start of creep travel, and the engine ignition timing AOL is calculated in step 413 using this correction amount EA. Will come to be.
For this reason, it is possible to suppress an increase in the traveling speed due to the ignition timing advance angle due to the ignition timing rotation speed control during creep traveling, and it is possible to prevent a stall from occurring due to deterioration of engine combustion.
[0056]
(2) Second embodiment
Next, a second embodiment of the present invention will be described. In the first embodiment described above, when the vehicle starts creep running during execution of the ignition timing rotation speed control, the feedback correction amount EA is fixed to the value at the start of creep running, whereas In the present embodiment, the first embodiment is that the feedback correction amount is gradually changed to approach the basic ignition timing in accordance with the creep travel speed and the ignition timing correction direction (advanced side or retarded side). It is different from the form.
[0057]
FIG. 5 is a flowchart for explaining the ignition timing rotation speed control operation of the present embodiment. Also in this embodiment, the operation of FIG. 5 is executed at regular intervals by the ECU 10 instead of the operation of FIG.
In FIG. 5, it is determined in step 501 whether or not the ignition timing rotation speed control is currently being executed. If not, the value of the ignition timing feedback correction amount EA is set to zero. If the ignition timing rotation speed control is currently being executed (IN = 1), then in step 505, the current vehicle travel speed SPD is set to the first predetermined value A.₂It is determined whether or not this is the case. Predetermined value A₂Is a relatively large value (eg A₂≈15 Km / H). In step 505, the vehicle travel speed is a first predetermined value A.₂If it is smaller, then in step 507, the vehicle travel speed SPD is a second predetermined value A._ThreeIt is determined whether or not: Second predetermined value A_ThreeIs a relatively small value (eg, A_Three≒ 6Km / H).
[0058]
  And in step 507SPD> A _Three If it is, the ignition timing feedback control based on the rotational speed is executed in steps 509 to 517. Steps 509 to 517 are the same operations as steps 303 to 317 in FIG. That is, in this embodiment, even when the vehicle starts creeping, if the traveling speed is between the second predetermined value A3 and the first predetermined value A2, the normal ignition timing rotational speed control is performed. Will continue.
  On the other hand, if SPD ≧ A2 in step 505, then whether or not the ignition timing is corrected to the advance side by the current ignition timing rotation speed correction in step 519 is based on the value of the feedback correction amount EA. Is determined. In step 519, the ignition timing correction direction (advance or retard) is determined based on whether the value of EA is positive or negative. That is, since the ignition timing is represented by the crankshaft rotation angle up to the top dead center of the compression stroke, when the feedback correction amount EA is positive, the current ignition timing is corrected to the advance side. When the value of EA is negative, it is corrected to the retard side.
[0059]
If the ignition timing is corrected to the advance side in step 519 (EA> 0), the vehicle creep travel speed is currently relatively large, and the ignition timing is corrected to the advance side, so that the travel speed is further increased. May increase. Therefore, in this case, SPD ≧ A₂As long as this state continues, steps 521 to 525 are executed each time the operation of FIG. 5 is executed, and the feedback correction amount EA is decreased by a certain amount ΔEA until EA = 0. As a result, the ignition timing is gradually retarded, and further increase in the creep travel speed is prevented without causing a shock due to a sudden change in the ignition timing.
[0060]
Further, when the ignition timing is corrected to the retard side in step 505 (EA ≦ 0), it is unlikely that the creep travel speed will increase further, so the routine proceeds to step 509 and normal ignition timing rotational speed control is performed. Continue.
Similarly, in step 507, SPD ≦ A_ThreeIf so, then the routine proceeds to step 527, where it is determined whether or not the current ignition timing has been corrected to the retard side (EA <0). When the ignition timing is corrected to the retard side, the current vehicle traveling speed is relatively small (SPD ≦ A_ThreeIn addition, since the ignition timing is corrected to the retard side, there is a possibility that the creep travel speed may further decrease against the driver's intention. Therefore, in this case, in steps 527 to 533, the feedback correction amount EA is increased by a certain amount ΔEA for every operation execution until EA = 0. As a result, the ignition timing is gradually advanced, and a further decrease in the creep travel speed is prevented without causing a shock.
[0061]
If the ignition timing is corrected to the advance side in step 527 (EA ≧ 0), it is unlikely that the creep travel speed will decrease any further, so the routine proceeds to step 509 and normal ignition timing rotation speed control is continued. To do.
In this embodiment, unlike the first embodiment, the vehicle speed is set to the second predetermined value A even during creep running._ThreeAnd a first predetermined value A₂If it is between, the ignition timing rotation speed control is executed (steps 509 to 517), but the ignition timing rotation speed control of steps 509 to 517 is performed when the vehicle is stopped (SPD) as in the first embodiment. ≦ A₁) Only when the vehicle travel speed is the second predetermined value A._ThreeAnd a first predetermined value A₂If the value is between the two, the feedback correction amount EA can be fixed to the value at the start of creep travel.
[0062]
(3) Third embodiment
Next, a third embodiment of the present invention will be described.
In the present embodiment, when the vehicle starts creeping during execution of the ignition timing rotational speed control, when the engine temperature rises by a predetermined width or more after the start, or when the engine temperature exceeds a predetermined temperature, the engine It is determined that the combustion has improved, the ignition timing rotational speed control is stopped, and the feedback correction amount EA is reset to zero. Despite engine combustion improving, if the ignition timing is advanced by ignition timing rotation speed control, knocking is likely to occur, and drive torque fluctuations may occur during creep running. When the combustion improves, the ignition timing rotation speed control is stopped to prevent knocking. In this case, since the vehicle is creeping, a sudden shock may occur if the feedback correction amount EA is suddenly reset. Therefore, as in the second embodiment, the value of the feedback correction amount EA is gradually changed. It tries to return to zero.
[0063]
FIG. 6 is a flowchart for explaining the ignition timing rotational speed control operation of the present embodiment. The operation of FIG. 6 is executed at regular intervals by the ECU 10 instead of the operation of FIG.
In FIG. 6, in step 601, it is determined whether or not the ignition timing rotation speed control is currently being executed. If not (IN ≠ 1), the feedback correction amount EA is set to zero (step 603). ). If the ignition timing rotation speed control is currently being executed (IN = 1), the current engine coolant temperature THW is read from the coolant temperature sensor 9 in step 605. In the present embodiment, the coolant temperature THW is used as a parameter representing the engine temperature.
[0064]
Next, in step 607, it is determined whether or not the vehicle is currently starting creep travel. If the vehicle is not starting creep travel (the vehicle travel speed SPD detected by the speed sensor 109 is a predetermined value A).₁(A₁If ≦ 3Km / H) or less), the coolant temperature THW read in step 605 is set to THW.₀In Steps 611 to 619, normal ignition timing rotation speed control (similar to Steps 303 to 317 in FIG. 3) is performed. As a result, THW₀Stores the coolant temperature immediately before the vehicle starts creeping.
[0065]
If it is determined in step 607 that the vehicle has started creeping, the process proceeds to step 621 where the engine coolant temperature THW read in step 605 is equal to the predetermined temperature THW.₁It is determined whether or not it has been reached. THW₁Is the coolant temperature at which it can be determined that the engine warm-up has progressed and the combustion state has improved, for example, THW in this embodiment₁≒ 60 ℃ is set.
In step 621, the coolant temperature is THW.₁If not, the process proceeds to step 623, where the coolant temperature THW stored in step 609 is stored.₀The cooling water temperature THW is set to a predetermined width ΔT after the vehicle starts creeping.₁It is determined whether or not it has risen above. ΔT₁Is a cooling water temperature rise range in which it can be determined that the engine combustion state has improved. In this embodiment, for example, ΔT₁≒ 10 ℃ is set.
[0066]
In step 621, the cooling water temperature is a predetermined temperature THW.₁And the cooling water temperature rise after the start of creep travel is a predetermined value ΔT₁If it is less than this, it can be determined that the combustion state of the engine has not improved yet. In this case, the normal ignition timing rotational speed control in step 611 and subsequent steps is continued even during creep running. As a result, stall due to deterioration of combustion during creep running is prevented.
On the other hand, if at least one of step 621 or step 623 is determined to be positive, it is considered that the combustion state of the engine is improving, and therefore it is not necessary to continue the ignition timing rotation speed control. Further, if the ignition timing rotational speed control is continued in this state, for example, the ignition timing may be advanced excessively and knocking may occur. Therefore, in this case, the operation from step 625 is performed, and the ignition timing rotation speed control is stopped after the ignition timing feedback correction amount EA is gradually returned to zero.
[0067]
That is, in step 625, it is determined whether the ignition timing is currently corrected to the advance side (EA> 0) or the retard side (EA ≦ 0) by the ignition timing rotation speed control, and the ignition timing is set to the advance side. If corrected, the feedback correction amount EA is decreased by a certain amount ΔEA every time the operation is executed, and the ignition timing is gradually brought closer to the basic ignition timing (steps 635, 637, 641 and steps 617, 619). Similarly, when it is corrected to the retard side, the value of EA is increased by a certain amount ΔEA every time the operation is executed, and the ignition timing is gradually brought closer to the basic ignition timing (steps 627, 629, 633 and step 617). 619).
In both cases, after the value of the feedback correction amount EA passes through zero, the value of EA is fixed to zero (steps 633 and 641), and the value of the flag IN is set to 0 (steps 631 and 639). ).
[0068]
As a result, when the engine combustion state improves, ignition timing rotation speed control is stopped without causing a shock even during creep travel, and knocking is prevented from occurring.
In this embodiment, the ignition timing rotational speed control is stopped in accordance with the engine temperature during creep running. However, the engine temperature is not less than a predetermined range in combination with the control of the first or second embodiment described above. It is also possible to stop the ignition timing rotational speed control according to the creep travel speed until it rises or exceeds a predetermined value.
[0069]
(4) Fourth embodiment
Next, a fourth embodiment of the present invention will be described.
In the present embodiment, when the driver starts the vehicle during the ignition timing rotation speed control during creep driving or when the vehicle is stopped, and the engine load increases relatively rapidly, the driver's starting operation is smoothly performed. The ignition timing rotation speed control is stopped while changing the ignition timing so that it can be performed. As described in steps 201 and 203 in FIG. 2, when the driver depresses the accelerator pedal, it is determined that the idling operation has ended, so the value of the flag IN is reset to zero and the ignition timing rotation speed control is immediately stopped. Is done. However, during ignition timing rotation speed control, the ignition timing is corrected to the advance side or the retard side compared to the basic ignition timing. For this reason, a problem may arise if ignition timing rotation speed control is stopped immediately when the vehicle starts.
[0070]
For example, in the case where the ignition timing is corrected to the advance side, if the ignition timing is immediately retarded to the basic ignition timing, the engine may stall due to deterioration of combustion. Further, even if the engine does not stall, the engine output torque decreases due to deterioration of combustion, and the output torque at the start intended by the driver cannot be obtained, and the acceleration performance may deteriorate. On the other hand, if the start operation is performed while the ignition timing is advanced to prevent this, the basic ignition timing is further advanced due to an increase in load accompanying the start operation, causing knocking during the start operation, Compared to the start operation, the increase in the engine output is increased, and a so-called “jump” at the start may occur due to an increase in the output beyond the intention of the driver.
[0071]
On the other hand, when the ignition timing is corrected to the retarded side, if the ignition timing is immediately advanced to the basic ignition timing at the time of start operation, the output torque suddenly increases due to the rapid advance of the ignition timing. “Jump” may occur when starting. In order to prevent this, if the start operation is performed while the ignition timing is retarded, the ignition timing on the advance side necessary for the start operation can be obtained even if the basic ignition timing is advanced along with the start operation. Therefore, the engine output does not increase sufficiently, and the acceleration performance of the vehicle may deteriorate.
Therefore, in the present embodiment, when the engine load increases to some extent due to the vehicle start operation when the ignition timing rotation speed control is performed during vehicle creep traveling or when the vehicle is stopped, the ignition timing rotation speed control is stopped when the ignition timing rotation speed control is stopped. The method for returning to the basic ignition timing is changed according to the correction direction (advance or retard).
[0072]
That is, when the ignition timing is corrected to the advance side at the start operation, the feedback correction amount EA is immediately reset to zero in order to prevent the vehicle from “jumping out”. A deterioration in acceleration is prevented by temporarily increasing the amount of fuel supplied to the engine according to the value of the feedback correction amount EA.
[0073]
In other words, the ignition timing rotation speed control is executed when the engine combustion state has deteriorated. Therefore, simply stopping the advance correction of the ignition timing when the vehicle starts, the engine output is reduced due to the deterioration of combustion. May decrease. Therefore, in the present embodiment, when the ignition timing is corrected to the advance side, the engine according to the amount by which the period ignition timing is retarded by stopping the ignition timing rotation speed control (that is, the feedback correction amount EA). The amount of fuel supplied to the vehicle is temporarily increased to prevent deterioration of acceleration. This increase is temporary, and once the fuel is increased by an amount corresponding to the feedback correction amount EA, the increase in fuel is gradually reduced to zero, and the fuel supply amount becomes the value at the normal start. Return.
[0074]
On the other hand, when the ignition timing is corrected to the retard side during the vehicle start operation, the feedback correction amount EA is gradually approached to zero, and the ignition timing is gradually advanced to perform basic ignition during a normal start operation. You are approaching the time. As a result, the engine output is restored to the value at the time of a normal start operation, and deterioration of acceleration performance is prevented. The reason why the feedback correction amount EA is gradually brought close to zero at the time of the retard side correction is that when the EA is immediately reset to zero, a rapid advance of the ignition timing occurs, and the engine output increases more than the driver intended. This is because there are cases.
[0075]
7 and 8 are flowcharts for explaining the ignition timing rotation speed control of the present embodiment. 7 and 8 are executed at regular intervals by the ECU 10 instead of the operation of FIG.
In FIG. 7, it is determined in step 701 whether or not ignition timing rotation speed control is currently being executed. If it is being executed (IN = 1), normal ignition timing rotation speed control is performed in steps 703 to 713. In step 709, the value of a flag IN2 described later is set to 1. Steps 703 to 707 and 711 and 713 are the same operations as steps 303 to 313, 315 and 317 in FIG. 3. Further, the flag IN2 is a flag having a function of causing the operations of steps 723 to 735 to be executed only at the time of a start operation, as will be described later.
[0076]
If IN ≠ 1 in step 701, it is then determined in step 715 whether or not the driver is performing an engine load increasing operation (vehicle starting operation).
The presence or absence of the engine load increasing operation is based on whether the opening THA of the throttle valve 16 detected by the throttle valve opening sensor 17 is a predetermined value THA.₀Judgment is made based on whether or not the above is true. Predetermined value THA₀Is a throttle valve opening corresponding to the driver's accelerator pedal depression amount during a normal vehicle start operation, and is set to about 30 degrees in this embodiment, for example.
If the driver does not perform the start operation in step 715, the value of the flag IN becomes zero because conditions other than the start operation are satisfied (for example, it is determined that the engine temperature has increased and combustion has improved). Since it is considered that the engine has been reset, there is no problem in starting operation even if the ignition timing rotational speed control is immediately stopped. Therefore, in this case, the value of the feedback correction amount EA is immediately reset to zero in step 717, and the value of the flag IN2 is reset to zero in step 719.
[0077]
On the other hand, in step 715, THA ≧ THA₀In this case, it is considered that the value of the ignition timing rotation speed control execution flag IN was reset to zero in step 203 in FIG. 2 because the driver performed the start operation. In this case, the process proceeds to step 721, where it is determined whether or not the value of the flag IN2 is set to 1.
As will be described later, the value of the flag IN2 is always set to 1 in step 709 during execution of the ignition timing rotation speed control, and is reset to zero when the operations of steps 723 to 735 are completed during the start operation. For this reason, if IN2 ≠ 1 in step 721, the operation after step 723 has been completed, so the process proceeds to step 717, where the value of EA is immediately reset to zero and steps 711 and 713 are executed. .
[0078]
On the other hand, if IN2 = 1 in step 721, the operation after step 723 is not completed, so the ignition timing return operation after step 723 is performed.
That is, in this case, the operation after step 723 is executed, and the following operation is performed depending on whether the current ignition timing (at the start of the start operation) is corrected to the advance side or the retard side. .
[0079]
That is, in step 723, it is determined whether the current ignition timing is corrected to the advance side or the retard side based on whether the feedback correction amount EA is positive or negative. If the ignition timing is corrected to the advance side in step 723 (EA ≧ 0), the feedback correction amount EA is reset to zero in steps 725, 727, and 717, and the fuel injection amount of the engine is temporarily set. The operation to increase is performed.
In this case, in step 725, the fuel increase initial value Q is determined in accordance with the current feedback correction amount EA (that is, at the start of the starting operation)._INC0Is determined based on a predetermined relationship. Fuel increase initial value Q_INC0Is set to a larger value as the value of EA is larger, that is, as the retard angle width of the ignition timing due to the stop of the ignition timing rotation speed correction is larger, preventing deterioration of combustion and a decrease in output torque due to the retard of the ignition timing. Has been.
[0080]
In step 725, the fuel increase initial value Q_INC0In step 727, the value of the fuel increase execution flag F is set to 1. Thereby, in the fuel injection amount calculation operation of FIG. 8 described below, the fuel injection amount is set to the initial value Q._INC0After increasing the amount only, an operation of gradually decreasing the amount of increase is performed.
Further, after execution of step 727, the process proceeds to step 717, where the value of the feedback correction amount EA is reset to zero, and in step 719, the value of the aforementioned flag IN2 is reset to zero.
[0081]
FIG. 8 is a flowchart showing a fuel injection amount calculation operation of the engine 1 that is executed by the ECU 10 at regular intervals.
In FIG. 8, in step 801, it is first determined whether or not the value of the fuel injection amount increase execution flag F is set to 1. The value of the flag F is set to 1 at step 727 in FIG. 7, and is set to zero at step 811 in FIG. 8 after the fuel increase is completed. If F ≠ 1 in step 801, the fuel increase is not executed and the value of a counter C, which will be described later, is reset to zero in step 803. Then, the process proceeds to step 813, and the fuel increase Q_INCSet the value of to zero. In step 815, the fuel injection amount Q is determined using a predetermined relationship based on the engine load (for example, the intake pressure detected by the intake pressure sensor 3 and the engine speed)._INJIs calculated.
[0082]
In step 817, the calculated Q_INJAnd Q_INCThe actual fuel injection amount Q using the value of_INJAQ_INJA= Q_INJ+ Q_INCCalculate as That is, if F ≠ 1 in step 801, Q_INCSince = 0 is set, the fuel injection amount is not increased.
On the other hand, if F = 1 in step 801, the process proceeds to step 805, where the value of the counter C is increased by 1. Since the value of the counter C is always set to zero in step 803 while F ≠ 1 in step 801, the value of the counter C after being increased in step 805 is the value after the fuel increase starts (F = It is a value corresponding to the elapsed time since it was set to 1.
[0083]
Next, at step 807, the fuel increase amount Q_INCIs the initial value Q set according to the value of EA in step 719 in FIG._INC0And counter C, Q_INC= Q_INC0−C × ΔQ_INCIs calculated as Where ΔQ_INCIs a positive constant value. As a result, the fuel increase amount Q_INCIs the initial value Q_INC0As the value of the counter C increases, the amount decreases (as time elapses after the fuel increase starts).
In step 809, the increase amount Q calculated in step 807 is set._INCIt is determined whether the value of is less than or equal to zero and Q_INCIf> 0, steps 815 and 817 are executed, and the amount of increase Q calculated in step 807 is_INCOnly increase the fuel injection amount.
[0084]
In step 809, increase amount Q_INCIf the value decreases to zero or less, the routine proceeds to step 811 where the value of the fuel increase execution flag F is reset to zero and at step 813 the Q_INCIs set to zero and steps 815 and 817 are executed.
As described above, in the fuel injection amount calculation operation of FIG. 8, the vehicle is started with the ignition timing corrected to the advance side in FIG. 7, and the value of the ignition timing feedback correction amount EA is immediately reset to zero. First, the amount Q according to the value of EA_INC0Only the fuel injection amount to the engine is increased, and then the fuel injection amount increase is gradually reduced to return to the normal fuel injection amount.
[0085]
On the other hand, when the ignition timing is corrected to the retard side in step 723 in FIG. 7 (when EA <0), an operation of gradually advancing the ignition timing to the basic ignition timing is performed in steps 729 to 735. Done.
That is, at step 729, the value of the feedback correction amount EA is increased by a certain amount ΔEA. As a result, the value of EA gradually approaches zero each time the operation of step 727 is executed. Further, after the value of EA exceeds 0 in step 731, the value of flag IN2 is set to 0 in step 733, and the value of EA is set to 0 in step 735. As a result, the ignition timing is gradually advanced to reach the basic ignition timing.
When the value of the flag IN2 is reset to zero in step 719 or step 733, the operations in steps 721 to 735 are not performed from the next operation execution.
[0086]
As described above, in the present embodiment, when the start operation is performed during execution of the ignition timing rotational speed control, if the ignition timing is corrected to the advance side when the start operation is performed, the feedback correction amount is immediately The value of EA is reset to zero to prevent the vehicle from “jumping out” and the amount of fuel supplied to the engine is increased to prevent a decrease in engine output due to worsening combustion (steps 723 to 727 and 717 and 719). ). If the ignition timing has been corrected to the retard side, the feedback correction amount EA is gradually returned to zero, and the ignition timing is gradually advanced to the basic ignition timing, thereby preventing deterioration in acceleration. An operation is performed.
[0087]
In this embodiment, at the time of starting operation (THA ≧ THA at step 715) without distinction between the starting operation from when the vehicle is stopped and the starting operation from during creep running.₀Step 723 and subsequent operations are performed.
In the present embodiment, as long as the flag IN is set to 1, normal ignition timing rotation speed control (steps 703 to 707, and 711, 713) is always performed. It is also possible to perform ignition timing control based on the traveling speed similar to that in the second embodiment, or ignition timing control based on the engine temperature as in the third embodiment, or both.
[0088]
【The invention's effect】
According to the invention described in each claim, when the vehicle starts running during execution of the ignition timing rotation speed control at the time of engine cold idling, the driving force suddenly changes or knocks, or the start operation is inhibited. There is a common effect that the ignition timing can be returned to the normal value.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a schematic configuration of an embodiment when the present invention is applied to an automobile internal combustion engine.
FIG. 2 is a flowchart illustrating an intake air amount rotation speed control operation.
FIG. 3 is a flowchart illustrating an example of a conventional ignition timing rotation speed control operation.
FIG. 4 is a flowchart illustrating a first embodiment of an ignition timing rotation speed control operation according to the present invention.
FIG. 5 is a flowchart for explaining a second embodiment of the ignition timing rotation speed control operation of the present invention.
FIG. 6 is a flowchart for explaining a third embodiment of the ignition timing rotation speed control operation of the present invention.
FIG. 7 is a flowchart illustrating a fourth embodiment of the ignition timing rotation speed control operation according to the present invention.
FIG. 8 is a flowchart for explaining a fuel injection calculation operation executed in the fourth embodiment.
[Explanation of symbols]
1 ... Internal combustion engine body
5, 6 ... Crank angle sensor
10: Electronic control unit (ECU)
16 ... Electronically controlled throttle valve
109 ... travel speed sensor
110 ... Ignition circuit

Claims (5)

When a predetermined condition is established during engine cold idle operation, the engine ignition timing correction amount is calculated according to the engine speed, and the basic ignition timing determined based on the engine operating state is corrected using the correction amount. A control device for an internal combustion engine for a vehicle that controls the engine speed to a predetermined target speed by performing ignition timing speed control.
If the vehicle starts creeping during execution of the ignition timing rotational speed control, the ignition timing rotational speed control is stopped and the correction amount at the start of creep traveling is stored. A control apparatus for an internal combustion engine, which corrects the basic ignition timing using the stored correction amount regardless of whether or not. When a predetermined condition is established during engine cold idle operation, the engine ignition timing correction amount is calculated according to the engine speed, and the basic ignition timing determined based on the engine operating state is corrected using the correction amount. A control device for an internal combustion engine for a vehicle that controls the engine speed to a predetermined target speed by performing ignition timing speed control.
When the vehicle starts creeping during the ignition timing rotation speed control,
When the engine ignition timing is corrected to the advance side by the ignition timing rotation speed control and the vehicle creep travel speed is equal to or higher than a predetermined first predetermined speed, the ignition timing rotation speed control is stopped. While the vehicle creep travel speed is equal to or higher than the first predetermined speed, the correction amount that is being attenuated is used while performing an attenuation operation that gradually brings the correction amount when the ignition timing rotation speed control is stopped to zero. The creep travel speed increase suppression operation for gradually bringing the engine ignition timing closer to the basic ignition timing by correcting the basic ignition timing,
When the engine ignition timing is corrected to the retard side by the ignition timing rotation speed control and the vehicle creep travel speed is equal to or lower than a second predetermined speed smaller than the first predetermined speed, the ignition While the timing rotation speed control is stopped and the vehicle creep travel speed is equal to or lower than the second predetermined speed, while performing the damping operation to gradually bring the correction amount when the ignition timing rotation speed control is stopped to zero, A control apparatus for an internal combustion engine, which performs a creep travel speed reduction suppressing operation for gradually bringing the engine ignition timing closer to the basic ignition timing by correcting the basic ignition timing using a correction amount during damping. When a predetermined condition is established during engine cold idle operation, the engine ignition timing correction amount is calculated according to the engine speed, and the basic ignition timing determined based on the engine operating state is corrected using the correction amount. A control device for an internal combustion engine for a vehicle that controls the engine speed to a predetermined target speed by performing ignition timing speed control.
When the vehicle starts creeping during the ignition timing rotation speed control,
The engine temperature at the start of creep travel is stored, and after the start of creep travel, the engine temperature rises by a predetermined width or more from the engine temperature at the start of creep travel, or the engine temperature exceeds a predetermined temperature. When the engine ignition timing is reached, the engine ignition timing is corrected by stopping the ignition timing rotational speed control and correcting the basic ignition timing using the correction amount that is being attenuated while performing an attenuation operation that gradually brings the correction amount closer to zero. A control device for an internal combustion engine that performs a return operation to gradually bring the engine closer to the basic ignition timing. When a predetermined condition is established during engine cold idle operation, the engine ignition timing correction amount is calculated according to the engine speed, and the basic ignition timing determined based on the engine operating state is corrected using the correction amount. A control device for an internal combustion engine for a vehicle that controls the engine speed to a predetermined target speed by performing ignition timing speed control.
When the engine throttle opening is equal to or greater than a predetermined value when the vehicle is stopped or creeping during execution of the ignition timing rotational speed control, the ignition timing rotational speed control is stopped,
When the engine ignition timing is corrected to the advance side when the ignition timing rotation speed control is stopped, the engine ignition timing is immediately returned to the basic ignition timing, and when it is corrected to the retard side, the correction amount is gradually increased. A control device for an internal combustion engine that performs a return operation for gradually returning the engine ignition timing to the basic ignition timing by correcting the basic ignition timing using the correction amount that is being attenuated while performing an attenuation operation that approaches zero. If the engine ignition timing is corrected to the advance side at the start of the return operation, the fuel supply amount to the engine is increased by an amount corresponding to the ignition timing correction amount, and the increase amount after the increase is made zero. The control apparatus for an internal combustion engine according to claim 4, wherein the control apparatus gradually decreases until it reaches.

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