JP5149215B2 - Engine control device - Google Patents

Description

  The present invention relates to an engine control device that adjusts engine output in response to an acceleration request based on, for example, a driver's accelerator operation.

In a gasoline engine, it is common to adjust the output by changing the amount of intake air using a throttle valve provided in an intake pipe. In such an engine, when the engine output changes suddenly, for example, when the accelerator is suddenly turned on after the accelerator is turned off, backlash that is unavoidably provided in a power transmission mechanism such as a transmission is suddenly clogged. Etc. may occur.
On the other hand, for example, Patent Document 1 describes an engine control device that reduces acceleration shock by correcting the fuel injection amount to be increased when the throttle valve is opened.

Japanese Patent Laid-Open No. 2004-150312

In the case of a vehicle equipped with an electric throttle that drives a throttle valve with an electric actuator, the throttle valve is opened and closed when the accelerator is depressed and returned for the purpose of preventing acceleration shock as described above. It has been proposed to perform a control that delays the operation and lowers the throttle response.
However, when such delay control is always performed, the throttle opens slowly even when backlash is clogged, for example, when accelerating from a constant speed or when increasing acceleration from gradual acceleration. Therefore, the responsiveness (throttle response) to the accelerator operation is reduced.

On the other hand, when the load state of the engine is equal to or greater than a predetermined value, it may be determined that the backlash of the power transmission mechanism is clogged and canceling the delay control when the accelerator is on.
However, when the throttle valve closing delay control is performed when the accelerator is returned, the backlash of the power transmission mechanism is open even when the engine load state is determined to be equal to or greater than the predetermined value. Even in such a case, if the delay control when the accelerator is on is canceled, an acceleration shock occurs.
The subject of this invention is providing the engine control apparatus which suppressed generation | occurrence | production of the acceleration shock at the time of improving an output from the state which is performing output reduction delay control.

The present invention solves the above-described problems by the following means.
The invention of claim 1 is an engine control device for controlling an engine that drives a wheel via a power transmission mechanism, the acceleration request detecting means for detecting an acceleration request, and the output of the acceleration request detecting means based on the output of the acceleration request detecting means. Engine output adjusting means for adjusting output of the engine and performing output reduction delay control for delaying and reducing the output of the engine with respect to the decrease in acceleration request when the acceleration request is decreased; and Backlash determination means for determining whether backlash is clogged based on a parameter correlated with the output torque of the engine, and the engine output adjustment means increases the output of the engine in response to an increase in the acceleration request. In response to an increase in the first control mode and the acceleration request, the output of the engine is delayed from the first control mode. And when the backlash determining means determines that the backlash is clogged, the first control mode is selected and the backlash is open. If it is determined that the second control mode is selected, the acceleration request is input again when the output reduction delay control is executed, regardless of the parameter correlated with the engine output torque. An engine control device that selects a second control mode.

According to a second aspect of the present invention, the engine output adjusting means adjusts the engine output by controlling an actuator that opens and closes a throttle valve provided in an intake pipe of the engine, and the backlash determining means includes: 2. The engine control device according to claim 1, wherein the backlash is determined to be clogged when an intake pipe pressure on the engine side of the throttle valve is larger than a threshold value.
The invention according to claim 3 is characterized in that the threshold value in the backlash determination means is set based on data relating to the pressure in the intake pipe when the vehicle travels at a constant speed. It is.
According to a fourth aspect of the present invention, the engine output adjusting means executes the output reduction delay control when the control target torque of the engine increases by a predetermined value or more with respect to the acceleration request torque set based on the acceleration request. The engine control device according to any one of claims 1 to 3, wherein it is determined that the engine is operating.

According to the present invention, the following effects can be obtained.
(1) By selecting the second control mode regardless of the parameter correlated with the engine output torque when executing the output reduction delay control, the accelerator is executed when executing the output reduction delay control in which the backlash of the power transmission mechanism is open. When is turned on again, the second control mode for delaying the increase in output is executed, so that it is possible to prevent acceleration shock from occurring.
(2) By determining the presence or absence of backlash based on the pressure in the intake pipe that can be directly detected by the pressure sensor and highly correlated with the torque, for example, from the engine speed, fuel injection amount, throttle opening, etc. The presence or absence of backlash can be determined with high accuracy when estimating the output torque of the engine.
(3) By setting the threshold value of the pressure in the intake pipe based on data relating to the pressure in the intake pipe when the vehicle travels at a constant speed, whether the vehicle is traveling or accelerating at a constant speed and the backlash is clogged, Alternatively, it can be well determined whether the vehicle is decelerating and the backlash is open.
(4) By determining that the output reduction delay control is being executed when the engine control target torque is increased by a predetermined value or more with respect to the acceleration request torque set based on the acceleration request, the output reduction delay control is performed. Execution can be detected easily and accurately.

It is a mimetic diagram showing composition of vehicles which have an example of an engine control device to which the present invention is applied. 3 is a graph showing an example of a transition between a driver request torque and a control target torque in the engine control apparatus of FIG. 1. It is a flowchart which shows the necessity determination of DA control implementation in the engine control apparatus of FIG. 2 is a graph showing an intake manifold pressure when the vehicle of FIG. 1 travels on a flat road at a constant speed. 6 is a graph showing another example of changes in driver request torque and control target torque in the engine control apparatus of FIG. 1. 6 is a graph showing another example of changes in driver request torque and control target torque in the engine control apparatus of FIG. 1.

  An object of the present invention is to provide an engine control device that suppresses the occurrence of acceleration shock when improving output from a state in which output reduction delay control is performed. This is solved by determining whether it is necessary and executing the output increase delay control regardless of the intake manifold pressure when executing the output decrease delay control.

Embodiments of an engine control apparatus to which the present invention is applied will be described below.
The engine control apparatus according to the embodiment controls, for example, a gasoline engine that is mounted on an automobile such as a passenger car and performs output adjustment using an electric throttle valve.
FIG. 1 is a schematic diagram illustrating a configuration of a vehicle including an engine control device according to an embodiment.

The vehicle 1 includes an engine 10, a transmission 20, an accelerator pedal 30, an engine control unit (ECU) 100, and the like.
The engine 10 is, for example, a four-stroke gasoline engine, and includes an intake chamber 11, a throttle 12, an intake manifold 13, and the like.
The intake chamber 11 is a container-like member into which combustion air filtered by an air filter (not shown) is introduced.
The throttle 12 is provided in the intake pipe line between the intake chamber 11 and the intake manifold 13. The throttle 12 includes a throttle valve that adjusts the amount of combustion air introduced into the intake manifold 13. The throttle valve is a so-called electric throttle that is driven by an actuator such as an electric motor (not shown).
The intake manifold 13 is a branch pipe that distributes the air discharged from the throttle 12 to the intake ports of the cylinders of the engine 10.

The transmission 20 is, for example, a manual transmission with 6 forward speeds and 1 reverse speed. The transmission 20 has a drive shaft and a driven shaft arranged in parallel. The drive shaft is an input shaft that is connected to the crankshaft of the engine 10 via a clutch. The driven shaft is an output shaft that drives the wheels W via a transfer, a differential, a drive shaft, and the like. A gear train corresponding to each gear stage is provided between the drive shaft and the driven shaft, and these gear trains are selected by engaging means such as a hub sleeve according to a driver shift operation. Is done.
The accelerator pedal 30 is an operation unit that is provided in the vehicle interior and inputs an acceleration request when the driver steps on the accelerator pedal 30.

The engine control unit 100 is an information processing apparatus that comprehensively controls the engine 10 and its auxiliary devices, and includes a storage unit such as a RAM and a ROM, a calculation unit such as a CPU, an input / output interface, and the like. Has been.
The engine control unit 100 is an engine control device according to the present invention, and includes an acceleration request detection means 110, a throttle control means 120, a backlash determination means 130, and the like.

  The acceleration request detecting means 110 detects an operation amount (depression amount) of the accelerator pedal 30 by the driver, and calculates a driver request torque based on this. An accelerator pedal position sensor 111 that detects an operation amount of the accelerator pedal 30 is connected to the acceleration request detecting means 110. The output of the accelerator pedal position sensor 111 is also transmitted to the backlash determination means 130.

The throttle control unit 120 is an engine output adjusting unit that controls the electric actuator of the throttle 12 based on the driver request torque calculated by the acceleration request detection unit 110 and opens and closes the throttle valve. The throttle valve is controlled to open and close so that the torque generated by the engine substantially matches the control target torque set based on the driver request torque. The throttle control means 120 includes a throttle position sensor 121 that detects the position of the throttle valve of the throttle 12.
Here, when the operation amount of the accelerator pedal 30 is steady, the driver request torque and the control target torque are set to substantially coincide. On the other hand, in a transient state such as when the driver depresses or returns the accelerator pedal 30, the throttle control means 120 determines the change in the control target torque as the acceleration request torque in order to suppress acceleration shock and deceleration shock. A DA (Acceleration-Deceleration) control and an AD (Deceleration-Acceleration) control are performed to delay the time with respect to the change of the signal.

FIG. 2 is a graph showing an example of changes in driver request torque and control target torque in the engine control apparatus of the embodiment. In FIG. 2, the horizontal axis indicates time, and the vertical axis indicates torque. In FIG. 2, the driver required torque is indicated by a solid line and the control target torque is indicated by a broken line. (Same for FIGS. 5 and 6)
As shown in FIG. 2, when the accelerator pedal 30 is depressed and the driver request torque increases, the throttle control means 120 of the ECU 100 performs DA control that delays the control target torque with respect to the driver request torque. In DA control, the increase rate of the control target torque with respect to the increase rate of the driver request torque (the slope of the graph in FIG. 2) is reduced, and the increase rate of the control target torque is further reduced particularly in a region where the control target torque is small. Yes. As a result, when the accelerator pedal 30 starts to be depressed, the engine 10 gently increases the output to close the backlash of the transmission 20 and the like, and then increases the output of the engine 10 to suppress the acceleration shock. This AD control is terminated when the output torque of the engine 10 increases and substantially matches the driver request torque.

On the other hand, in the AD control, when the driver request torque decreases due to the accelerator pedal 30 being turned off, in the region where the driver request torque is small, the decrease rate of the control target torque is made smaller than the decrease rate of the driver request torque. . As a result, the torque of the engine 10 rapidly decreases, and the deceleration shock that occurs when the backlash of the transmission 20 is suddenly changed from the state where the backlash is blocked on the acceleration side to the state where it is blocked on the deceleration side is suppressed.
Further, the ECU 100 according to the embodiment has a function of determining whether or not the backlash of the power transmission mechanism such as the transmission 20 is clogged to the acceleration side and canceling the above-described DA control according to the determination result. This point will be described in detail later.

The backlash determination means 130 determines whether or not backlash (backlash) of the power transmission mechanism such as the transmission 20, a differential (not shown), or a drive shaft is clogged on the acceleration side (driving force transmission side). The backlash determination means 130 determines that the backlash is clogged when the vehicle 1 is traveling on a flat road surface on a constant side.
An intake manifold pressure sensor 131, an atmospheric pressure sensor 132, a crank angle sensor 133, a vehicle speed sensor 134, a shift position sensor 135, and the like are connected to the backlash determination means 130.

The intake manifold pressure sensor 131 detects the pressure in the intake manifold 13 of the engine 10.
The atmospheric pressure sensor 132 detects the atmospheric pressure in the atmosphere around the vehicle 1.
The crank angle sensor 133 outputs a pulse signal corresponding to the rotation of a crankshaft (not shown) of the engine 10. The backlash determination means 130 can acquire the rotational speed (rotational speed) of the engine 10 calculated based on the output of the crank angle sensor 133.
The vehicle speed sensor 134 is provided, for example, in a wheel hub portion that rotatably supports the wheel, and outputs a pulse signal corresponding to the traveling speed (vehicle speed) of the vehicle 1. The backlash determination means 130 can acquire the vehicle speed of the vehicle 1 calculated based on the output of the vehicle speed sensor 134.
The shift position sensor 135 detects the currently selected gear position in the transmission 20 and transmits it to the backlash determination means 130.

Hereafter, the necessity determination of DA control implementation mentioned above is demonstrated. FIG. 3 is a flowchart showing whether or not DA control execution is necessary.
Hereinafter, the steps will be described step by step.
<Step S01: Judgment of vehicle speed>
Based on the output of the vehicle speed sensor 134, the backlash determination means 130 determines whether the vehicle speed is equal to or higher than a predetermined value set in advance.
If the vehicle speed is equal to or higher than the predetermined value, it is assumed that the vehicle 1 is traveling and the process proceeds to step S02. If the vehicle speed is less than the predetermined value, the process proceeds to step S08 assuming that the vehicle 1 is stopped or traveling at a very low speed close thereto.

<Step S02: Determination of accelerator opening>
The backlash determination means 130 determines whether the accelerator opening detected based on the output of the accelerator pedal position sensor 111 is equal to or greater than a predetermined value set in advance.
If the accelerator opening is equal to or greater than the predetermined value, it is assumed that the driver intends to accelerate and the process proceeds to step S03. If the accelerator opening is less than the predetermined value, the process proceeds to step S08 assuming that the driver does not intend to accelerate.

<Step S03: Determination of abnormality of each sensor>
The backlash determination means 130 is used to detect various problems such as intake manifold pressure sensor 131, atmospheric pressure sensor 132, crank angle sensor 133, vehicle speed sensor 134, shift position sensor 135, and other information transmission means such as an in-vehicle LAN system. Diagnose whether there is an abnormality such as disconnection. If there is no abnormality, the process proceeds to step S04. If there is an abnormality, the process proceeds to step S08.

<Step S04: Determination of Difference between Control Target Torque and Driver Required Torque>
The backlash determination means 130 compares the difference value obtained by subtracting the driver request torque from the control target torque with a preset threshold torque, and if the difference value is equal to or less than the threshold torque, the process proceeds to step S05, where the difference value is the threshold value. If it exceeds the torque, the process proceeds to step S08.
The threshold torque is set to a small value of about 0.8 Nm, for example, and the DA control is canceled only when the difference between the control target torque and the driver request torque is substantially close to zero. It has become.

<Step S05: Calculation of threshold intake manifold pressure>
The backlash determination means 130 calculates a threshold intake manifold internal pressure used in step S06 described later. The threshold intake manifold pressure is calculated by multiplying a reference pressure determined based on the rotation speed of the engine 10 and the shift position (shift stage) of the transmission 20 by a correction coefficient determined based on the atmospheric pressure.

The reference pressure is, for example, an intake manifold pressure (absolute pressure) when the vehicle 1 travels on a flat road at a constant speed in an environment of atmospheric pressure 760 mmHg, and is based on a reference pressure table in which experimental values measured in advance are accumulated. Read out.
An example of the reference pressure table is shown in Table 1. FIG. 4 is a graph showing the reference pressure, where the horizontal axis shows the engine speed and the vertical axis shows the pressure. As shown in Table 1 and FIG. 4, the reference pressure increases as the shift speed becomes higher, and the reference pressure increases approximately in a quadratic curve as the engine speed increases at a shift speed of 2nd speed or higher. is doing. When an intermediate value of discrete data is necessary, a desired intermediate value is calculated by a predetermined interpolation process.

The correction coefficient is provided in consideration of the fact that when the air resistance of the vehicle 1 is reduced at high altitudes where the air becomes thin, the engine output required for constant speed traveling decreases, and the intake manifold pressure at this time also decreases. It has been. Table 2 is a table showing an example of the correction coefficient. As shown in Table 2, the correction coefficient is 1 (no correction) when the atmospheric pressure is 760 mmHg, and the correction coefficient is set to gradually decrease as the atmospheric pressure decreases from here. .

<Step S06: Pressure determination in intake manifold>
The backlash determination means 130 compares the actual intake manifold internal pressure detected by the intake manifold pressure sensor 131 with the threshold intake manifold internal pressure calculated in step S05. If the actual intake manifold internal pressure is equal to or higher than the threshold intake manifold internal pressure, it is determined that the backlash of the transmission 20 or the like is clogged to the acceleration side, and the process proceeds to step S07. On the other hand, when the actual intake manifold internal pressure is less than the threshold intake manifold internal pressure, it is determined that the backlash of the transmission 20 or the like is open (clogged to the deceleration side), and the process proceeds to step S08. .

<Step S07: DA control cancellation>
The throttle control unit 120 cancels the DA control that delays the increase of the control target torque according to the increase of the driver request torque or reduces the delay amount according to the determination result in step S06 by the backlash determination unit 130. Perform DA control. When performing DA control with a reduced amount of delay, for example, the throttle response may be improved by multiplying the rate of change of the control target torque in normal DA control by a coefficient of a predetermined magnification.
Thereafter, the series of processing is terminated (returned).

<Step S08: DA control execution>
Throttle control means 120 performs DA control that delays the increase in control target torque in accordance with the increase in driver request torque, in accordance with the determination result in step S06 by backlash determination means 130.
Thereafter, the series of processing is terminated (returned).

Hereinafter, effects of the above-described embodiment will be described.
FIG. 5 is a graph showing another example of changes in the driver request torque and the control target torque in the engine control apparatus of the embodiment.
In the embodiment, when the driver depresses the accelerator pedal 30 from the OFF state, DA control is performed, and the increase in the control target torque is delayed and the opening of the throttle 12 is delayed. It is possible to suppress the acceleration shock that occurs due to sudden clogging from the state in which the rush is open.

  Further, when the driver once returns the accelerator pedal 30 to the intermediate position from the accelerator-on state and depresses the accelerator pedal 30 again from this partial load state, the actual intake manifold pressure exceeds the threshold intake manifold pressure, and DA Since the control is canceled, the throttle 12 is opened with almost no delay with respect to the depression of the accelerator pedal 30, and the time delay of the engine output improvement with respect to the driver operation is reduced. At this time, since the backlash of the transmission 20 and the like is clogged on the acceleration side, no acceleration shock occurs even if the throttle 12 is opened early.

FIG. 6 is a graph showing another example of changes in the driver request torque and the control target torque in the engine control apparatus of the embodiment.
In the embodiment, AD control is performed when the driver returns the accelerator pedal 30, and the control target torque increases with respect to the driver request torque. At this time, if the difference value obtained by subtracting the driver request torque from the control target torque exceeds the threshold torque, the process proceeds from step S04 described above to step S08, and DA control is performed.

During such AD control, even if the intake manifold internal pressure is larger than the threshold intake manifold pressure, the backlash of the transmission 20 or the like is open (clogged to the deceleration side by the engine brake). Therefore, if the DA control is canceled, a large acceleration shock occurs when the driver depresses the accelerator pedal 30 again.
In this respect, according to the embodiment, when the control target torque is greater than or equal to the threshold torque with respect to the driver request torque by AD control (when the control target torque is substantially larger than the driver request torque because the threshold torque is minute) Therefore, by performing DA control, it is possible to prevent the occurrence of acceleration shock in such a case.

As described above, according to the embodiment, the following effects can be obtained.
(1) By not canceling DA control regardless of the intake manifold pressure during execution of AD control, DA control is performed when the accelerator is turned on again during execution of AD control when the backlash of the transmission 20 or the like is open. It is possible to prevent acceleration shock from occurring due to the cancellation of.
(2) By determining the presence or absence of backlash based on the pressure in the intake manifold that can be directly detected by the pressure sensor and highly correlated with the torque, for example, engine speed, fuel injection amount, throttle opening, etc. Therefore, it is possible to accurately determine the presence or absence of backlash in the case of estimating the output torque of the engine.
(3) By setting the threshold value of the intake manifold internal pressure based on the data related to the intake manifold internal pressure when the vehicle travels at a constant speed, the vehicle is traveling or accelerating at a constant speed and backlash is clogged. Or whether the vehicle is decelerating and the backlash is open can be satisfactorily determined.
(4) The AD control is executed by determining that the AD control is being executed when the engine control target torque is increased by a predetermined threshold torque or more with respect to the acceleration request torque set based on the acceleration request. It can be detected easily and accurately.

(Modification)
The present invention is not limited to the embodiments described above, and various modifications and changes are possible, and these are also within the technical scope of the present invention.
(1) In the above-described embodiment, the presence or absence of backlash of the power transmission mechanism is determined based on the intake manifold pressure, but may be determined by other methods. For example, the engine output torque is estimated based on various operating conditions such as engine speed, air flow meter flow rate, throttle opening, and fuel injection amount, and the estimated output torque is compared with the estimated vehicle running resistance. Thus, the presence or absence of backlash may be determined.
(2) In the above-described embodiment, the engine output is adjusted by the throttle valve. However, the present invention can also be applied to those that adjust the engine output by other methods. For example, in the case of a diesel engine, the engine output increase may be delayed with respect to the increase in the acceleration request described above by adjusting the fuel injection amount in the case of a diesel engine.

1 Vehicle 10 Engine 11 Intake Chamber 12 Throttle 13 Intake Manifold 20 Transmission 30 Accelerator Pedal 100 Engine Control Unit (ECU)
110 Acceleration Request Detection Unit 111 Accelerator Pedal Position Sensor 120 Throttle Control Unit 121 Throttle Position Sensor 130 Backlash Determination Unit 131 Intake Manifold Pressure Sensor 132 Atmospheric Pressure Sensor 133 Crank Angle Sensor 134 Vehicle Speed Sensor 135 Shift Position Sensor

Claims (4)

An engine control device that controls an engine that drives wheels via a power transmission mechanism,
An acceleration request detecting means for detecting an acceleration request;
Output adjustment of the engine is performed based on the output of the acceleration request detection means, and output reduction delay control is performed to reduce the output of the engine by delaying the decrease of the acceleration request when the acceleration request is decreased. Engine output adjusting means;
Backlash determination means for determining whether the backlash of the power transmission mechanism is clogged or not based on a parameter correlated with the output torque of the engine,
The engine output adjusting means has a first control mode for increasing the output of the engine in response to an increase in the acceleration request, and an output of the engine in accordance with an increase in the acceleration request from the first control mode. The second control mode is also delayed and increased, and when the backlash determination means determines that the backlash is clogged, the first control mode is selected and the backlash is opened. The second control mode is selected, and when the acceleration request is input again during the execution of the output reduction delay control, the parameter relating to the output torque of the engine is selected. The engine control apparatus, wherein the second control mode is selected. The engine output adjusting means adjusts the output of the engine by controlling an actuator that opens and closes a throttle valve provided in an intake pipe of the engine,
2. The engine control device according to claim 1, wherein the backlash determination unit determines that the backlash is clogged when an intake pipe pressure on the engine side of the throttle valve is larger than a threshold value. . The engine control apparatus according to claim 2, wherein the threshold value in the backlash determination means is set based on data relating to an intake pipe pressure when the vehicle travels at a constant speed. The engine output adjustment means determines that the output reduction delay control is being executed when the control target torque of the engine increases by a predetermined value or more with respect to the acceleration request torque set based on the acceleration request. The engine control device according to claim 1, wherein:

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