JPH10246132A - Control device for hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To absorb a torque step difference generated by an engine by calculating a torque step difference value generated by the engine according to demand torque to the engine, an operating condition of the engine, and an engine control switching signal, and controlling an electric motor according to the torque step difference. SOLUTION: In control in the case where combustion of an engine 101 is changed from stoichiometric air-fuel ratio combustion to lean combustion, an engine control switching signal is outputted according to accelerating operation of a driver and the like by engine control switching means 107, and an air-fuel ratio is changed following with the engine control switching signal and a demand torque by an engine control means 105. A torque step difference is calculated from the demand torque, an engine operating condition, and the engine control switching signal by a torque step difference calculating means 106, and an electric motor 102 is controlled by a motor control means 104 so as to offset the torque step difference. A composite torque of the engine 101 and the electric motor 102 is set to a constant value so as to solve disorder feeling applied on the driver.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a hybrid vehicle in which an engine and an electric motor are connected on an axle of the vehicle and one or both of them drive the vehicle.
The present invention relates to a control device for a hybrid vehicle that can suppress a sudden change in torque generated from an engine and purify exhaust gas generated from the engine.

[0002]

2. Description of the Related Art Hitherto, a hybrid vehicle has been proposed in which an engine is assisted by an electric motor to make exhaust gas exhausted cleaner. In this type of hybrid vehicle, the vehicle driving state such as the accelerator opening and the vehicle speed is detected, and the sharing of use between the engine and the electric motor is controlled.

For example, in a hybrid vehicle proposed in Japanese Patent Laid-Open Publication No. Sho 59-204402, a motor mode, a power generation mode, a regenerative mode, and an engine mode are appropriately selected in accordance with a required operating state. so,
Driving with engine-efficient rotation speed and output,
An operation in which the amount of exhaust gas is reduced is performed by driving a motor.

Further, when the driver performs a rapid accelerator operation, it is necessary to change the output of the engine in accordance with the change in the required output, and the air-fuel ratio control cannot be maintained.
Toxic substances in the exhaust gas will increase. As a conventional technique for solving this problem, for example, Japanese Patent Application Laid-Open
There is a hybrid vehicle proposed in Japanese Patent Publication No. 088905, which limits the output of the engine in response to a driver's accelerator operation within a range of a predetermined rate of change, that is, a range in which air-fuel ratio control is maintained, and becomes insufficient or extra. The torque will be supplemented by an electric motor.

[0005]

However, according to this configuration, it is possible to prevent the exhaust from deteriorating due to a sudden torque change request of the driver, but it is possible to suppress the torque fluctuation of the engine itself which is not related to the driver's request. I can't. Here, the torque fluctuation of the engine itself means
For example, (1) an engine torque step that occurs when switching between lean combustion and stoichiometric air-fuel ratio combustion in a lean-burn engine, and (2) when switching between stratified combustion and homogeneous combustion in an in-cylinder direct fuel injection engine. (3) An engine torque step generated when switching valve timing in an engine having a variable valve timing mechanism.

Further, according to this configuration, it is not possible to respond to a sudden change in torque demanded by a driver other than the driver without deteriorating the exhaust gas. The abrupt torque change request required from a driver other than the driver here is, for example,
(4) Request for reduction of engine torque output from a means for detecting idling when tires idle due to excessive driving force with respect to the road surface condition; (5) Reduction of shock during shifting with an automatic transmission mechanism In order to reduce and increase the engine torque.

[0007] These engine torque steps or engine torque reduction requests are very fast changing speeds and cannot be handled by controlling the intake air amount of the engine. In addition, controlling the ignition timing limits the torque control range, and further has an effect on the engine exhaust and fuel efficiency. Further, by controlling the torque by the fuel cut, it is possible to control only in a decreasing direction, and since the cut is performed for each cylinder, the controllable torque value is:
Only discrete values can be realized.

The present invention has been made in view of the above-mentioned problems of the prior art, and abrupt changes in driving torque for absorbing a torque step generated by the engine itself or improving the performance of the vehicle. It is an object of the present invention to provide a control device for a hybrid vehicle which can realize the above-mentioned conditions without deteriorating the exhaust performance and the like.

[0009]

In order to achieve the above object, a control apparatus for a hybrid vehicle according to the present invention according to a first aspect of the present invention provides a control apparatus for a hybrid vehicle having an engine for driving a vehicle and an electric motor. Engine control switching means for outputting an engine control switching signal according to the required torque and the operating state of the engine; engine control means for controlling the engine according to the required torque for the engine, the operating state of the engine and the engine control switching signal; A torque step calculating means for calculating a torque step value generated by the engine in accordance with a required torque to the engine, an operating state of the engine, and an engine control switching signal; and a motor control means for controlling an electric motor in accordance with the torque step value. It is characterized by having.

According to a second aspect of the present invention, the engine control switching means is means for switching between lean combustion and stoichiometric combustion of the engine.

According to a third aspect of the present invention, the engine control switching means is means for switching between stratified combustion and homogeneous combustion of the engine.

According to a fourth aspect of the present invention, the engine control switching means is means for switching engine valve timing.

In the control apparatus for a hybrid vehicle according to the first to fourth aspects of the present invention, the electric motor generates torque so as to absorb a torque step of the engine generated when the control state of the engine is switched. Drivability of the vehicle is improved, and it is possible to prevent the driver from feeling uncomfortable. At that time, there is no accompanying increase in harmful components in the exhaust gas.

According to a fifth aspect of the present invention, there is provided a hybrid vehicle control apparatus for detecting a change in the state of a vehicle in a hybrid vehicle including an engine for driving a vehicle and an electric motor. Vehicle state change detection means, engine control means for controlling the engine according to the required torque to the engine and the operating state of the engine,
Motor torque calculating means for calculating a motor torque command value according to a required torque to the engine, a change in the operating state of the engine, and a change in the vehicle state; and a motor control means for controlling the motor according to the motor torque command value. It is characterized by.

7. The hybrid vehicle control device according to claim 6, wherein the vehicle state change is a tire idling, and the motor torque calculating means calculates a motor torque command value for preventing the tire from idling. Means.

8. The control system for a hybrid vehicle according to claim 7, wherein the change in the state of the vehicle is a shift of an automatic transmission, and the motor torque calculating means includes a motor torque for preventing a shock generated by the shift. It is a means for calculating a command value.

In the control apparatus for a hybrid vehicle according to the fifth to seventh aspects of the present invention, when the change in the driving state of the vehicle is detected, the sudden drive torque to be changed is
Since the electric power is generated by the electric motor instead of the engine, it is possible to improve the drivability of the vehicle without increasing the harmful components in the exhaust gas.

[0018]

According to the present invention, the torque step generated by the engine is absorbed by the electric motor.
Drivability of the vehicle is improved without affecting the exhaust.

According to the present invention, when the driving force needs to be rapidly changed, the change is generated by the electric motor, so that the drivability of the vehicle is improved without affecting the exhaust. I do.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. First Embodiment FIG. 1 is a block diagram showing a first embodiment of the present invention. In the figure, 101 is an engine for driving a vehicle,
Reference numeral 102 denotes an electric motor that is connected to the axle and drives the vehicle, similarly to the engine 101. 103 is the motor 10
A battery 104 serving as a power source for the second motor controls electric power supplied from the battery 103, and a motor control means for driving the electric motor 102 in accordance with the torque step. A battery 105 includes an intake air amount of the engine 101, a fuel injection amount, Engine control means for controlling the ignition timing and the like, and driving the engine 101 according to the engine operating state, the required torque and the engine control switching signal.

Reference numeral 106 denotes an engine 101 according to a required torque, an engine operating state, and an engine control switching signal.
Torque step calculating means for calculating a torque step generated by
Reference numeral 107 denotes an engine control switching unit that determines an engine control mode according to the required torque and the engine operating state, and outputs an engine control switching signal.

Next, the case where the combustion of the engine 101 is switched from the stoichiometric air-fuel ratio combustion to the lean combustion (lean burn) will be specifically described by way of example. FIG. 2 shows a case where ideal switching can be realized. Engine control switching according to the engine operating state, that is, the engine speed, water temperature, etc., and the required torque, ie, the torque command value calculated from the driver's accelerator operation and the vehicle speed, the torque command value from the vehicle speed control device, and the like. Means 107 outputs an engine control switching signal for switching the combustion mode of engine 101 from stoichiometric air-fuel ratio combustion to lean combustion at time t1.

The engine control means 105 changes the air-fuel ratio R according to the engine control switching signal and the required torque so as to satisfy the required torque. That is, the intake air amount Q is changed at time t1 as shown in FIG. The change of the intake air amount Q is realized by controlling a slot actuator of a throttle valve, etc., but the actual intake air amount Q changes smoothly as shown in FIG. 2 mainly due to the dynamics of the intake system. . Accordingly, the fuel injection amount P is changed by controlling the fuel injection device. As a result of such control, the torque T of the engine 101 becomes constant despite changing the combustion mode.

However, in the conventional hybrid vehicle, harmful components contained in the exhaust gas increase during this process. That is, during the change of the combustion mode, the air-fuel ratio continuously changes from the stoichiometric air-fuel ratio to the air-fuel ratio of the lean combustion.
In a certain air-fuel ratio range, harmful segments cannot be removed due to the performance of the exhaust catalyst.

In order to solve this problem, in the hybrid vehicle according to the present embodiment, as shown in FIG.
1 and the electric motor 102 are controlled.

The intake air amount Q is changed in the same manner as described with reference to FIG. 2, but the fuel injection amount P is changed as shown in FIG. Then, the air-fuel ratio R changes stepwise.
That is, the time during which the air-fuel ratio at which the harmful components in the exhaust gas increase is extremely short.

However, because of this, the engine torque TE
Is not constant, and a step occurs in the process of changing the combustion mode. Therefore, the torque step calculating means 106
Calculates this torque step from the required torque, the engine operating state such as the number of revolutions, and the engine control switching signal. Then, the motor control element stage 104 controls the electric motor 102 so as to cancel the torque step. As a result, as shown in FIG. 3, the combined torque T between the engine 101 and the electric motor 102 becomes constant, and a sense of discomfort to the driver is prevented,
Drivability of the vehicle is improved.

The above description is a specific example in which the combustion of the engine is switched between stoichiometric and lean. Similarly, in the case of the direct fuel injection engine, for example, the stratified combustion and the homogeneous This control device can be applied when switching to combustion.

That is, the engine control switching means 107 is
As means for switching between stratified combustion and homogeneous combustion, the torque step calculating means 106 is provided with an engine 1 generated at the time of the switching.
01 means for calculating a torque step.

By doing so, the torque fluctuation of the engine 101 itself that occurs when switching between stratified combustion and homogeneous combustion can be offset by the electric motor 102. As a result, the combined torque T between the engine 101 and the electric motor 102 becomes constant. This prevents the driver from feeling uncomfortable and improves the drivability of the vehicle.

The same applies to the case of the engine 101 and the engine control means 105 to which the variable valve timing mechanism is added. That is, the engine control switching means 1
07 is a means for switching the valve timing, and the torque step calculating means 106 is a means for calculating the torque step of the engine 101 generated at the time of the switching.

By doing so, the torque fluctuation of the engine 101 itself that occurs when the valve timing is switched can be canceled by the electric motor 102. As a result, the engine 1
01 and the electric motor 102 become constant, the discomfort to the driver is prevented, and the drivability of the vehicle is improved.

Second Embodiment Next, a second embodiment of the present invention will be described. FIG.
FIG. 3 is a block diagram showing a second embodiment. In the figure, 101 is an engine that drives the vehicle, and 102 is an electric motor that is connected to the axle and drives the vehicle similarly to the engine 101. Reference numeral 103 denotes a battery serving as a power source for the electric motor 102; 104, a motor control means for controlling electric power supplied from the battery 103 to drive the electric motor 102 in accordance with a torque command value; Control the amount, fuel injection amount, ignition timing, etc.,
The engine 1 according to the engine operating state and the required torque
01 is an engine control means for driving the motor.

Reference numeral 108 denotes a motor torque calculating means for calculating a torque command value generated by the motor according to the required torque, the engine operating state and the vehicle state change detection signal.
Reference numeral 9 denotes a vehicle state change detecting unit that detects a vehicle state change from the vehicle state and outputs a vehicle state change detection signal request torque.

Next, a specific description will be given of an example in which the tires idle due to excessive driving force relative to the road surface condition and the idling is suppressed by reducing the driving force.

First, the vehicle state change detecting means 109 outputs a vehicle state change detection signal based on the vehicle state, that is, the vehicle speed and the wheel speed, that is, a signal indicating whether or not the tire is slipping. The engine control means 105
The engine 101 is controlled so as to realize the engine operating state and the required torque, that is, the torque command value of the engine 101 calculated from the accelerator operation of the driver or the like.

The motor torque calculating means 108 determines whether the tire is slipping according to the vehicle state change detection signal.
A negative torque command value to be generated by the electric motor 102 to reduce the driving force is calculated. Motor control means 104
Controls the electric motor 102 according to the negative torque command value.

As a result, the engine 101 and the electric motor 102
Is reduced, and the driving force generated by the tire is also reduced. Therefore, the grip force of the tire on the road surface is restored, and the slip is suppressed.

To achieve such an effect, it is conceivable to reduce the torque of the engine 101. However, it takes time to reduce the amount of intake air due to the dynamics of the intake system, and the fuel injection Controlling the amount and ignition timing has an effect on exhaust gas. These problems are solved by using the electric motor 102 as in the present embodiment.

The above description is a specific example applied to the case of detecting the idling state of the tire. However, the present control device can also be applied to a case where the shift shock of the automatic transmission is reduced.

In this case, the vehicle state change detecting means 10
Numeral 9 outputs a vehicle state change detection signal, that is, a shift operation state, based on the vehicle state, that is, the speed ratio and timing determined by the automatic transmission from the vehicle speed and the driver's accelerator operation.

The motor torque calculating means 108 calculates the torque command value to be generated by the motor 102, that is, the torque to be reduced so that the rotation speeds of the engine 101 and the motor 102 do not increase during the shift (neutral state). Then, a torque that gradually returns so as to smoothly connect at the end of the shift is calculated. Motor control means 104
Controls the electric motor 102 according to the torque command value. As a result, a shift shock can be prevented, and the drivability of the vehicle is improved.

To achieve such an effect, it is conceivable to change the torque of the engine 101. However, it takes time to change the amount of intake air due to the dynamics of the intake system. Controlling the amount and ignition timing has an effect on exhaust gas. These problems can be solved by using the electric motor 102 as in the present embodiment.

The embodiments described above are described for facilitating the understanding of the present invention, and are not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of a control device for a hybrid vehicle according to the present invention.

FIG. 2 is a waveform chart for explaining the operation of the first embodiment of the present invention.

FIG. 3 is a waveform chart for explaining the operation of the first embodiment of the present invention.

FIG. 4 is a block diagram showing a first embodiment of a control device for a hybrid vehicle according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 ... Engine 102 ... Electric motor 103 ... Battery 104 ... Electric motor control means 105 ... Engine control means 106 ... Torque step calculating means 107 ... Engine control switching means 108 ... Electric motor torque calculating means 109 ... Vehicle state change detecting means

Claims (7)

[Claims] 1. A hybrid vehicle including an engine for driving a vehicle and an electric motor, an engine control switching means for outputting an engine control switching signal according to a required torque for the engine and an operating state of the engine, and a request for the engine. Engine control means for controlling the engine in accordance with the torque, the operating state of the engine and the engine control switching signal, and calculating the torque required by the engine and the torque step value generated by the engine in accordance with the engine operating switching signal and the engine control switching signal A control device for a hybrid vehicle, comprising: a torque step calculating unit that performs the control; and a motor control unit that controls the motor in accordance with the torque step value. 2. The hybrid vehicle control device according to claim 1, wherein said engine control switching means is means for switching between lean combustion and stoichiometric combustion of the engine. 3. The hybrid vehicle control device according to claim 1, wherein said engine control switching means is means for switching between stratified combustion and homogeneous combustion of the engine. 4. The hybrid vehicle control device according to claim 1, wherein said engine control switching means is means for switching engine valve timing. 5. A hybrid vehicle comprising a vehicle driving engine and an electric motor, a vehicle state change detecting means for detecting a state change of the vehicle, and controlling the engine according to a required torque for the engine and an operating state of the engine. Motor control means for calculating a motor torque command value in accordance with a required torque for the engine and a change in the operating state and vehicle state of the engine, and a motor control means for controlling the motor in accordance with the motor torque command value A control device for a hybrid vehicle, comprising: 6. The vehicle according to claim 1, wherein the change in the state of the vehicle is a slip of a tire, and the motor torque calculating means calculates a motor torque command value for preventing the tire from slipping. 6. The control device for a hybrid vehicle according to claim 5. 7. The state change of the vehicle may be a shift of an automatic transmission, and the motor torque calculating means may be a means for calculating a motor torque command value for preventing a shock caused by the shift. The control device for a hybrid vehicle according to claim 5, wherein