JP2004301128A - Engine operation control device of hybrid electric vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine operation control device of a hybrid electric vehicle which can eliminate and reduce a sense of incongruity about engine revolution feeling against accelerator operation and, prevent a drop in battery voltage caused by quick accelerator operation. <P>SOLUTION: When a quantity of accelerator operation is detected by a means 8 for detecting the quantity of accelerator operation, accelerator operation speed is calculated by a means 61 for calculating the accelerator operation speed based on this detected information. Then a rate of change of the targeted opening of the throttle of an engine at the time of power generation is set by a means 62 for setting the rate of change of the targeted opening of the throttle corresponding to the accelerator operation speed. Thus, engine revolution speed is quickly increased in relation to the quick accelerator operation, and the sense of incongruity against the accelerator operation can be eliminated. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an engine operation control device suitable for use in a series hybrid electric vehicle.

  2. Description of the Related Art Hitherto, a hybrid electric vehicle in which an internal combustion engine (engine) and an electric motor (motor) are combined to obtain a driving force of a vehicle has been developed and put into practical use. Such hybrid electric vehicles include a series hybrid electric vehicle that uses an engine exclusively as a power supply source for a motor, and a parallel hybrid electric vehicle in which both an output shaft of an engine and an output shaft of a motor are mechanically connected to drive wheels. Electric vehicles are known.

  Among them, in a series-type hybrid electric vehicle, a motor is operated by power supply from a battery to run the vehicle. Then, when the remaining power of the battery becomes less than the first predetermined value (for example, 60%), the engine is operated to drive the generator, thereby charging the battery and supplying power to the motor. When the remaining capacity of the battery becomes equal to or more than a second predetermined value (for example, 65%) larger than the above-mentioned predetermined value, the operation of the engine is stopped and the power generation is stopped.

Here, during the operation of the engine (that is, at the time of power generation), the operation of the engine is performed with characteristics as shown in FIGS. 7 and 8.
First, a power generation amount instruction value (target power generation amount) is set from the map shown in FIG. 7 based on the accelerator pedal depression amount of the driver. The target power generation amount is set to a value in which the power generation amount required for traveling is further taken into consideration so that the remaining power of the battery tends to recover. As shown in the figure, the target power generation amount is set to a step-like characteristic. For example, when the accelerator pedal depression amount exceeds 10%, the target power generation amount is changed from 10 kW to 20 kW.

  As shown in FIGS. 8 (a) and 8 (b), when the accelerator opening is increased by depressing the accelerator and the target power generation amount is changed, the throttle actuator attached to the throttle starts operating at this point. The throttle opening increases and the engine output increases. As a result, the amount of power generation also increases, and the required power is obtained. The throttle actuator is formed of a stepper motor or the like, and the throttle opening is adjusted by appropriately changing a control signal for the stepper motor.

  This will be described with reference to a flowchart shown in FIG. 9. When the engine is operating, first, in step S10, a target power generation amount is set based on the accelerator depression amount. Then, in step S20, a target throttle opening is set based on the target power generation amount, and in step S30, the throttle actuator is driven to achieve the target throttle opening, and the throttle is opened and closed.

However, as shown in FIGS. 8A and 8B, conventionally, the rate of change of the throttle opening (throttle changing speed) is constant regardless of the stepping speed of the accelerator opening. There is a problem that a change in the engine rotation speed causes a sense of incompatibility.
That is, even in a series-type hybrid electric vehicle in which the engine and the driving wheels are not mechanically connected, for example, when the driver steps on the accelerator quickly, the faster the engine speed is, the more the driver feels. Conventionally, however, the operation speed of the throttle actuator is a constant value, which may not match the driver's feeling in some cases.

Also, if the driver steps on the accelerator quickly, the remaining capacity of the battery decreases and the battery voltage decreases from the increase in the power generation amount indication value to the actual increase in the power generation amount, and as a result, the motor output decreases. There is a problem that the running performance is reduced due to the suppression.
The present invention has been made in view of the above-described problems, and is a hybrid electric vehicle capable of reducing an uncomfortable feeling of an engine rotation with respect to an accelerator operation and preventing a decrease in a battery voltage when the accelerator is quickly depressed. It is an object of the present invention to provide an engine operation control device.

In the engine operation control device for a hybrid electric vehicle according to the first aspect of the present invention, when the accelerator pedal depression amount is detected by the accelerator pedal depression amount detecting means, the accelerator pedal speed calculating means calculates the accelerator pedal based on the detected information. Is calculated.
The target throttle opening change rate setting means sets the change rate of the target throttle opening of the engine during power generation according to the accelerator depression speed.

  As a result, when the accelerator is quickly depressed, the change rate of the target throttle opening of the engine is set to be large, and the engine rotational speed is quickly increased.

According to the engine operation control apparatus for a hybrid electric vehicle according to the present invention, the rate of change of the target throttle opening of the engine during power generation is set based on the depression speed of the accelerator pedal of the driver. There is an advantage that the engine can be operated in accordance with the feeling.
In addition, when the driver steps on the accelerator quickly, the engine speed increases quickly, so the time until the power generation actually increases can be shortened, and the remaining battery power until the engine speed increases. There is an advantage that it is possible to reliably prevent a situation in which the capacity is reduced and the traveling performance is reduced.

  Further, the configuration of the conventional hybrid electric vehicle only needs to be changed in the control logic, and there is no need to add any new parts, so that there is an advantage that the cost and weight do not increase.

  Hereinafter, an engine operation control device for a hybrid electric vehicle according to an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, a battery 1 is mounted on the hybrid electric vehicle, and the battery 1 It is electrically connected to the electric motor (motor) 3 via the electric motor. The motor 3 is connected to a driving wheel side of a vehicle (not shown), and the hybrid electric vehicle runs by driving the motor 3.

The hybrid electric vehicle is also provided with an engine 4, and an output side of the engine 4 is mechanically connected to a generator 5 for supplying electric power to the battery 1 and the motor 3. When the generator 5 is driven by the engine 4, electric power corresponding to the load of the generator 5 is generated.
In addition, the vehicle is provided with a control device (or simply referred to as a controller) 6 as control means to which various sensors are connected. The engine 4 and the generator 5 are controlled by a control signal from the controller 6. The operation is controlled on the basis of the operation.

  On the other hand, the accelerator pedal 7 is provided with an accelerator opening sensor (accelerator depression amount detecting means) 8, and an output corresponding to the depression amount of the accelerator pedal 7 by the driver is input to the motor controller 2 and the controller 6. I have. An instruction output to the motor 3 is set by the motor controller 2 based on an output signal of the accelerator opening sensor 8, and the motor 3 is driven according to the instruction output to the motor 3.

Further, the battery 1 is provided with a remaining capacity detecting means (specific gravity meter) 10 for detecting the remaining power of the electric power, and the remaining capacity of the battery 1 is detected by the specific gravity meter 10 and inputted to the controller 6. Has become.
Normally, when the remaining capacity of the battery 1 is equal to or more than a first predetermined value (for example, 60%), the vehicle is driven by the electric power stored in the battery 1, and the remaining capacity of the battery 1 is set to the first predetermined value. When it is less than the predetermined value, the engine 4 is operated to drive the generator 5. Then, at this time, the vehicle is run using the electric power generated by the generator 5, and the battery 1 is charged at the same time. Further, when the remaining capacity of the battery 1 recovers to a second predetermined value (for example, 65%) or more by the charging at this time, the operation of the engine 4 is stopped.

Further, the engine 4 is provided with a water temperature sensor (water temperature detecting means) 22 for detecting the temperature of the cooling water in the water jacket 21. When the engine 4 is started, the water temperature is lower than a predetermined temperature (for example, 60 ° C.). Then, the controller 6 executes the warm-up operation of the engine 4. Note that power is not generated during the warm-up operation.
During normal operation of the engine 4 (at the time of power generation), the output of the engine 4 is controlled according to the required power generation (target power generation). That is, when the target power generation amount is large, the throttle attached to the engine 4 is opened to increase the engine rotation speed, and when the target power generation amount is small, the throttle is closed to suppress the engine rotation speed. ing.

  The throttle has an actuator (throttle actuator, see reference numeral 4a in FIG. 2) for driving the throttle valve to change the throttle opening. The operation of the actuator 4a is controlled by a control signal from the controller 6. It is supposed to be. Note that, for example, a stepper motor is applied as the throttle actuator 4a.

  By the way, as shown in FIG. 2, the controller 6 is provided with an accelerator depression speed calculating means 61 and a target throttle opening change rate setting means 62. The accelerator depression speed calculating means 61 calculates the rate of change of the accelerator opening (that is, the accelerator depression speed) based on the detection information from the accelerator opening sensor 8. The target throttle opening change rate setting means 62 sets the target throttle opening change rate (target throttle change speed) of the engine 4 during operation of the engine 4 (that is, during power generation).

  Here, the target throttle opening change rate setting means 62 stores, for example, a map as shown in FIG. 3B. According to the accelerator depressing speed calculated by the accelerator depressing speed calculating means 61, The target throttle change speed is set. Specifically, the faster the accelerator pedal is depressed, the higher the target throttle change speed is set. The characteristics for setting the target throttle change speed are not limited to those shown in FIG. 3 (b), but may have characteristics such that the throttle change speed increases at least as the accelerator opening increases. Other characteristics may be used.

When the target throttle change speed is set by the target throttle opening change rate setting means 62, the control signal is sent from the controller 6 to the throttle actuator 4a so that the change speed of the throttle opening becomes the target throttle change speed. Is output.
As shown in the figure, the controller 6 is provided with a first target power generation amount setting means 63, a second target power generation amount setting means 64 and a selection means 65. The opening is set.

Among these, the first target power generation amount setting means 63 and the second target power generation amount setting means 64 are means for individually setting the target power generation amounts based on different parameters, respectively. This is a means for comparing the values set by the target power generation amount setting means 63 and 64 and selecting the larger value.
Here, the first target power generation amount setting means 63 is provided with a map as shown in FIG. 4A, and the target is set in a stepwise manner based on the accelerator depression amount, similarly to the above-described conventional technology. The amount of power generation is set. Further, a map as shown in FIG. 4B is provided in the second target power generation amount setting means 64 so that the target power generation amount is set from the required output of the motor 3. Note that the required output of the motor 3 is calculated from the power consumption of an inverter (not shown) attached to the motor 3.

The selecting unit 65 selects the larger one of these two target power generation amounts. As shown in FIG. 3A, the selection means 65 is provided with a map for converting the selected target power generation amount into a throttle opening, and the target throttle of the throttle actuator 4a is used by using this map. The opening is set.
Thus, by selecting the larger one of the two target power generation amounts, the engine 4 can be operated such that the remaining capacity of the battery 1 tends to recover during power generation traveling by the engine 4. is there. Note that the target power generation amount may be simply set based on the accelerator depression amount without providing the second target power generation amount setting unit 64 and the selection unit 65.

Since the engine operation control device for a hybrid electric vehicle according to one embodiment of the present invention is configured as described above, the throttle actuator 4a is driven based on, for example, the flowchart shown in FIG.
That is, when the engine 4 is operating (except during warm-up operation), the first target power generation amount setting means 63 gradually increases the target power generation amount based on the accelerator depression amount obtained from the accelerator sensor 8. At the same time, the target power generation amount is set stepwise from the required output of the motor 3 by the second target power generation amount setting means 64, and the larger one of them is selected by the selection means 65 (step S1). Then, a target throttle opening corresponding to the selected target power generation amount is set from a map as shown in FIG. 3A (step S2).

On the other hand, based on the detection information from the accelerator opening sensor 8, the accelerator depression speed calculating means 61 calculates the rate of change of the accelerator opening (that is, the accelerator depression speed). Then, the target throttle change rate setting means 62 sets the target throttle change rate according to the accelerator pedal depressing speed from a map as shown in FIG. 3B (step S3).
When the target throttle change speed and throttle opening are calculated in this way, the controller 6 sets the throttle valve opening and its change speed to the target throttle opening and target throttle change speed. The throttle actuator 4a is driven (step S4).

Therefore, as shown in FIGS. 5 (a) and 5 (b), the accelerator pedal is depressed during power generation traveling by the engine 4 (see the upper graph in the figure), thereby increasing the target power generation by one level (the middle graph). ), A control signal is output from the controller 6 to the actuator 4a, and the throttle opening is changed according to the control signal (see the lower graph).
At this time, as shown in FIGS. 5 (a) and 5 (b), even if the accelerator depression speed (the gradient of the graph) is different, if the accelerator depression amount is the same, the throttle opening amount itself that is changed as a result is not changed. The same, but the rate of change of the throttle opening is set according to the accelerator depressing speed, so if you depress the accelerator quickly, the engine speed will increase quickly, and if you depress the accelerator slowly. The engine speed increases slowly so that the driver does not feel uncomfortable.

  As described above, according to the engine operation control device for a hybrid electric vehicle according to the embodiment of the present invention, the rate of change of the target throttle opening of the engine 4 during power generation is set according to the accelerator pedal depression speed. When the accelerator is depressed quickly, the change rate of the target throttle opening of the engine 4 is set to a large value, and the engine speed is quickly increased, so that it is possible to eliminate an uncomfortable feeling with the accelerator operation and match the driver's feeling. There is an advantage that the operation of the engine 4 can be performed.

In addition, when the driver depresses the accelerator quickly, the engine speed increases quickly, which can reduce the time from the increase in target power generation to the actual increase in power generation, increasing the engine speed. By doing so, there is an advantage that it is possible to reliably prevent a situation where the remaining capacity of the battery 1 is further reduced and the running performance is reduced.
Further, since the control logic only needs to be changed without adding any new parts to the configuration of the conventional hybrid electric vehicle, there is an advantage that cost and weight do not increase.

  In addition, a larger value is selected from the target power generation amount set based on the detection information of the accelerator sensor 8 and the target power generation amount set based on the required output required by the motor 3. Since the target throttle opening of the engine 4 is set based on the target power generation amount thus set, the engine 4 can be operated such that the remaining capacity of the battery tends to recover during power generation traveling by the engine 4. There are benefits too.

  The engine operation control device for a hybrid electric vehicle according to the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the present invention is not limited to a series-type hybrid electric vehicle, but can be widely applied to a hybrid electric vehicle having at least a mode in which an engine is operated for power generation.

FIG. 1 is a diagram for describing an overall configuration of a hybrid electric vehicle to which the present invention is applied. 1 is a schematic block diagram illustrating a main configuration of an engine operation control device for a hybrid electric vehicle according to an embodiment of the present invention. (A), (b) is a diagram for explaining the operation of the engine operation control device of the hybrid electric vehicle according to an embodiment of the present invention, and sets the target throttle opening and target throttle change speed of the engine, respectively. It is a map for. (A), (b) is a diagram for explaining the operation of the engine operation control device of the hybrid electric vehicle according to an embodiment of the present invention, is a map for setting a target power generation amount. (A), (b) is a figure explaining the operation | movement of the engine operation control apparatus of the hybrid electric vehicle concerning one Embodiment of this invention. 4 is a flowchart illustrating an operation of the engine operation control device for the hybrid electric vehicle according to the embodiment of the present invention. FIG. 9 is a diagram for explaining a conventional technique. FIG. 9 is a diagram for explaining a conventional technique. FIG. 9 is a diagram for explaining a conventional technique.

Explanation of reference numerals

1 battery 3 electric motor
4 engine 5 generator 6 control means (controller)
7 Accelerator pedal 8 Accelerator depression amount detection means (accelerator sensor)
61 accelerator depression speed calculation means 62 target throttle opening change rate setting means 63 first target power generation amount setting means 64 second target power generation amount setting means 65 selection means

Claims (1)

An engine operation control device for a hybrid electric vehicle including at least an electric motor and an engine,
Accelerator depression amount detecting means for detecting the depression amount of the accelerator pedal,
Accelerator depressing speed calculating means for calculating a depressing speed of the accelerator pedal based on detection information from the accelerator depressing amount detecting means,
Target throttle opening change rate setting means for setting a change rate of a target throttle opening during power generation operation of the engine based on the accelerator stepping speed calculated by the accelerator stepping speed calculating means. An engine operation control device for a hybrid electric vehicle.

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