JP2022131154A - Control device for hybrid vehicle - Google Patents

Abstract

To provide a control device for a hybrid vehicle capable of generating demand drive force while curbing an increase in temperatures of a motor and a battery.SOLUTION: A control device is for a hybrid vehicle which: comprises an engine, a motor which has a power generation function, a transmission which is installed on an output side of a drive force source, a clutch which is installed between the drive force source and the transmission and a battery which is electrically connected to the motor; increases an engine rotation speed with the clutch released; and generates drive force with the clutch engaged when starting the vehicle in a stopped state. The control device causes the motor to be driven with engine torque with the vehicle in the stopped state for generating power and charging the battery. The control device also stops power generation when at least either a temperature of the motor or a temperature of the battery reaches a threshold and causes the engine and the motor to output drive torque when the vehicle in the stopped state is started.SELECTED DRAWING: Figure 2

Description

The present invention relates to a control device for a hybrid vehicle having an engine and a motor having a power generation function as driving force sources.

Patent Literature 1 describes a control device for a hybrid vehicle having an engine as a driving force source and a motor having a power generation function. The control device described in Patent Document 1 generates power by the motor when the vehicle is started with the maximum drive torque from a stop state, that is, when the vehicle is started, and assists the drive torque by the motor in addition to the engine torque when starting the vehicle. is configured as More specifically, when the brake pedal is depressed and the accelerator pedal is depressed, the driving torque of the engine is offset by the power generation torque (negative torque) of the motor to generate electricity. When the braking force becomes "0", the power generation by the motor is stopped, and the vehicle is started by the drive torque of the engine and the drive torque of the motor.

In addition, in Patent Document 2, when the launch is started, the temperature of the starting clutch is lowered in advance by using a cooling liquid that is lower in temperature than usual, thereby suppressing seizure of the starting clutch and ensuring acceleration performance. A clutch cooling device is described that is configured to.

Japanese Unexamined Patent Application Publication No. 2016-078704 Japanese Unexamined Patent Application Publication No. 2020-076482

The control device described in Patent Literature 1 described above is configured to satisfy acceleration by outputting electric power generated by the motor as drive torque in addition to engine torque when launching. However, when launching, the vehicle starts from a stopped state, so the cooling performance of the motor and the battery may deteriorate. If the motor and battery are continuously controlled under such conditions, the temperature of the motor and battery may rise before the battery is fully charged or charged to the specified value, and the torque assist function of the motor may deteriorate. be. In such a case, the output of the battery and the motor may decrease, and the required driving force may not be generated, and the desired acceleration may not be obtained.

SUMMARY OF THE INVENTION The present invention has been conceived by paying attention to the above technical problems, and provides a control device for a hybrid vehicle capable of generating a required driving force while suppressing an increase in the temperature of a motor and a battery. It is intended for

In order to achieve the above object, the present invention provides an engine as a driving force source and a motor having a power generation function, a transmission provided on the output side of the driving force source, and the driving force source and the transmission. and a battery electrically connected to the motor. A control device for a hybrid vehicle configured to generate driving force by engaging a clutch, comprising a controller for controlling the vehicle, wherein the controller drives the motor with the torque of the engine when the vehicle is stopped. When the temperature of at least one of the temperature of the motor and the temperature of the battery reaches a predetermined threshold value, the power generation is stopped and the vehicle is stopped. It is characterized in that when the vehicle is started, driving torque is output from the engine and the motor.

According to the hybrid vehicle control apparatus of the present invention, in the case of so-called launch start, the vehicle Ve is started by outputting maximum torque from the engine and the motor. Specifically, when the vehicle is stopped, with the clutch released, the engine drives the motor to generate power, charges the battery, and stops power generation when the temperature of the motor and battery reaches a threshold value. In this state, since the SOC of the battery is increasing, the vehicle is started by outputting drive torque (assist torque) from the motor in addition to the engine. As a result, the driving force requested by the driver can be generated at the time of starting, and as a result, the vehicle can be started with desired acceleration. Moreover, as described above, the power generation is stopped when the temperature of the motor or the battery reaches the threshold value. Therefore, it is possible to prevent the temperature (coil temperature) of the battery and the motor from rising excessively, and as a result, it is possible to prevent the output of the motor and the battery from decreasing. That is, it is possible to generate maximum power and start the vehicle while protecting the battery and motor components, and as a result, desired acceleration can be obtained.

1 is a schematic diagram showing an example of a vehicle targeted by the present invention; FIG. 4 is a time chart for explaining an example of control in the embodiment of the invention; FIG. 3 is a schematic diagram showing another example of a vehicle targeted by the present invention;

Embodiments of the present invention will be described with reference to the drawings. It should be noted that the embodiment shown below is merely an example when the present invention is embodied, and does not limit the present invention.

FIG. 1 schematically shows an example of a hybrid vehicle to be controlled in an embodiment of the invention. The example shown here is an example of a hybrid vehicle based on a so-called FR (front engine/rear drive) vehicle that transmits the power of the engine 1 to the rear wheels 2 . A hybrid vehicle (hereinafter referred to as vehicle) Ve shown in FIG. 1 includes, as power sources, an engine (ENG) 1 and a motor (MG) 3 capable of transmitting torque to rear wheels 2 . The vehicle Ve also includes a battery (BATT) 4, an automatic transmission (TM) 5, a clutch 6, and an ECU (electronic control unit) 7 as other major components. The target vehicle Ve is not limited to the vehicle shown in FIG. There may be.

The engine 1 is, for example, an internal combustion engine such as a gasoline engine or a diesel engine, and is configured such that its output is adjusted and operating conditions such as starting and stopping are electrically controlled. In the case of a gasoline engine, the opening of the throttle valve, the amount of fuel supplied or injected, execution and stop of ignition, ignition timing, etc. are electrically controlled. In the case of a diesel engine, the amount of fuel injection, the timing of fuel injection, or the opening of a throttle valve in an EGR (Exhaust Gas Recirculation) system is electrically controlled.

The motor 3 is arranged on the output side of the engine 1 . The motor 3 has at least a function as a generator that generates electricity by being driven by receiving the engine torque output by the engine 1 . In the vehicle Ve according to the embodiment of the present invention, the motor 3 also functions as an electric motor that is driven by electric power supply and outputs motor torque. That is, the motor 3 is a motor having a power generation function (so-called motor generator), and is configured by, for example, a permanent magnet synchronous motor or an induction motor. A battery 4 is connected to the motor 3 via an inverter (not shown). Therefore, the motor 3 can be driven as a generator and the electricity generated at that time can be stored in the battery 4 . Alternatively, the electricity stored in the battery 4 can be supplied to the motor 3, and the motor 3 can be driven as an electric motor to output motor torque.

The battery 4 is a power storage device that stores electricity generated by the motor 3, and is connected to the motor 3 so as to be able to transmit and receive electric power. Therefore, the electricity generated by the motor 3 can be stored in the battery 4 as described above. Also, the electricity stored in the battery 4 can be supplied to the motor 3 to drive the motor 3 . Note that the power storage device is not limited to the battery shown in FIG. 1, and may be, for example, a capacitor.

The automatic transmission 5 is arranged on the same axis as the engine 1 and on the output side of the motor 3 as shown in FIG. , and a transmission mechanism that transmits torque via the differential device 8 . The automatic transmission 5 is, in short, a mechanism capable of appropriately changing the ratio of the input rotation speed to the output rotation speed, and is capable of setting a plurality of gear ratios stepwise. In the example shown in FIG. 1, the geared automatic transmission is configured to change the drive torque transmission path by engaging or disengaging an engagement mechanism (not shown) to execute gear shifting. .

As shown in FIG. 1, a clutch 6 is provided between the automatic transmission 5 and the engine 1 and motor 3 to selectively transmit and interrupt torque. This clutch 6 is, as is conventionally known, a frictional engagement mechanism that is engaged and released by hydraulic pressure, for example, so that its torque capacity (transmission torque capacity) can be changed continuously. It is configured. Specifically, the clutch 6 has friction plates connected to rotating members on the engine 1 and motor 3 sides, and friction plates connected to rotating members on the rear wheel 2 side (both not shown). ). The clutch 6 can also be configured by, for example, a multi-plate clutch in which a plurality of friction plates are alternately arranged. By disengaging the clutch 6, the engine 1 and the motor 3 are disconnected from the drive system of the vehicle Ve. By engaging the clutch 6, the engine 1 and the motor 3 are connected to the drive system of the vehicle Ve. In other words, the example shown in FIG. 1 is configured to selectively transmit and interrupt power between the engine 1 and motor 3 and the rear wheels 2 . In the example shown in FIG. 1, the front wheels 9 are steering wheels.

The ECU 7 corresponds to the "controller" in the embodiment of the invention, and mainly controls the automatic transmission 5, the engine 1, the motor 3, the battery 4, the clutch 6, etc. in the example shown in FIG. The ECU 7 is an electronic control device mainly composed of a microcomputer, for example, and receives input of data detected or calculated from various sensors. The input data includes, for example, the on/off signal of the launch control switch 10, the accelerator opening, the brake signal, the vehicle speed, the wheel speed, the engine speed, the motor speed, the engine torque, the motor torque, and the clutch 6. torque capacity, etc. Further, the ECU 7 performs calculations using various input data, pre-stored data, calculation formulas, etc., and outputs the calculation results as control command signals to control the engine 1, the motor 3, the battery 4, the engine 1, the motor 3, the battery 4, It is configured to control the automatic transmission 5, the clutch 6, and the like.

As described above, the vehicle Ve configured in this way outputs torque from the engine 1 and the motor 3 because the required driving force and the required acceleration increase when the vehicle Ve is launched. Specifically, when the vehicle is stopped, the launch control switch 10 (or an operation switch such as a sports mode) is turned on, and the accelerator pedal is depressed, the engine speed and engine torque are increased with the clutch 6 released. In order to charge the battery 4 at that time, the engine torque drives the motor 3 to generate electricity. As a result, the engine torque and motor torque generate a large driving force and acceleration. On the other hand, in the transitional period of launching (especially when the motor 3 is generating power and charging the battery 4), if the cooling performance of the battery 4 and the motor 3 is degraded, the power generation and charging In addition, the temperature of the motor 3 and the temperature of the battery 4 may rise excessively, and the respective outputs may decrease. In that case, it may not be possible to generate the acceleration and driving force required when starting the vehicle Ve. Therefore, the embodiment of the present invention is configured to suppress excessive temperature rise of the motor 3 and the battery 4 at the time of launch start.

FIG. 2 is a time chart showing an example of the control, showing an example in which the launch control switch 10 is turned on while the vehicle is stopped. A thick solid line indicates an example when the control in the embodiment of the present invention is executed, and a thin solid line indicates an example (conventional example) when this control is not executed.

Specifically, first, when the launch control switch 10 (or an operation switch such as a sports mode) is turned on, the clutch 6 is released, and when the accelerator is operated at a predetermined accelerator opening, the engine speed and The engine torque begins to increase (time t1). Further, the motor 3 functions as a generator by driving the motor 3 with the engine torque, and the battery 4 is charged with the generated electric power. Accordingly, at time t1, the SOC of battery 4 also begins to increase. Furthermore, by driving the motor 3 and starting to charge the battery 4, the temperature of the coil of the motor 3 and the temperature of the battery 4 rise.

Next, the increased temperature of the battery 4 reaches a threshold (BATT threshold 1), or the temperature of the coil of the motor 3 reaches a threshold (MG threshold 1) (time t2). Therefore, in order to suppress the temperature rise of the motor 3 and the battery 4 at time t2, the power generation torque is reduced. Further, along with this, the rate of increase of the SOC of the battery 4 becomes smaller. Note that the respective thresholds for the temperature of the battery 4 and the temperature of the coil of the motor 3 are such that the coil temperatures of the battery 4 and the motor 3 rise when maximum power is output from the motor 3 at the time of start (that is, acceleration). In anticipation of this, it is set lower than that.

Next, when the SOC of the battery 4 reaches a threshold (SOC threshold), the vehicle Ve is started (time t3). In other words, the engine 1 and the motor 3 are in a state where maximum power can be output. Therefore, at time t3, the clutch 6 is engaged and the accelerator opening is increased to the maximum. This further increases the engine torque and engine speed. The assist torque (driving torque) by the motor 3 also increases.

Then, by outputting drive torque from the motor 3, the SOC of the battery 4 begins to decrease. That is, electric power is supplied to the motor 3 and the SOC is lowered. Further, by outputting drive torque from the motor 3, the temperature of the battery 4 rises to the threshold (BATT threshold 2) and the coil temperature of the motor 3 rises to the threshold (MG threshold 2) (time t4). The thresholds for the temperature of the battery 4 and the temperature of the coil of the motor 3 are the temperatures at which the output of the motor 3 can be maximized, in other words, the temperature at which the output of the motor 3 does not decrease. After time t4, the temperature of the battery 4 and the temperature of the coil of the motor 3 reach the threshold values, so the drive torque of the motor 3 is reduced. This is to protect parts such as the motor 3 and the battery 4 .

Next, the operation of the embodiment of the invention will be described. As described above, the embodiment of the present invention is configured to output the maximum torque from the engine and the motor to start the vehicle Ve when launching. Specifically, when the vehicle is stopped, with the clutch 6 released, the motor 3 is driven by the engine 1 to generate power, and the battery 4 is charged. Stop. In this state, since the SOC of the battery 4 is increasing, the drive torque (assist torque) is output from the motor 3 in addition to the engine 1 to start the vehicle. As a result, as shown in the conventional example of FIG. 2, the SOC of the battery does not increase, and it is possible to avoid or suppress problems such as a small driving torque from the motor. That is, in the embodiment of the present invention, the driving force requested by the driver can be generated at the time of starting, and as a result, the vehicle can be started with desired acceleration.

Further, in the embodiment of the present invention, as described above, power generation is stopped when the temperature of the motor 3 or the battery 4 reaches the threshold value. Therefore, it is possible to prevent the temperature (coil temperature) of the battery 4 and the motor 3 from excessively increasing, and as a result, it is possible to prevent the output of the motor 3 and the battery 4 from decreasing. That is, it is possible to generate the maximum power to start the vehicle Ve while protecting the components such as the battery 4 and the motor 3, thereby obtaining desired acceleration.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above examples, and may be modified as appropriate within the scope of achieving the object of the present invention. In the above-described embodiment, a vehicle having an engine 1 and a single motor 3 is described as an example of the target vehicle Ve. FIG. 3 schematically shows an example of the hybrid vehicle. In the example shown here, the motor 11 is connected to the front wheels 12 so as to be able to transmit power. That is, the example shown in FIG. 3 is an example of a four-wheel drive vehicle (called 4WD or AWD) in which the power of the engine 1 and the motor 3 is transmitted to the rear wheels 2, and the power of the motor 11 is transmitted to the front wheels 12. is.

It should be noted that the motor 11 may be a motor having a power generation function (a so-called motor generator), like the motor 3 described above. Also, the motor 11 is connected to the battery 4 via an inverter (not shown). Furthermore, the motor 3 and the motor 11 are connected via an inverter so as to be able to exchange electric power with each other. Therefore, for example, the electricity generated by the motor 3 can be directly supplied to the motor 11 and the motor 11 can output the motor torque.

1 engine (ENG)
3, 11 motor (MG)
4 battery (BATT)
5 Automatic transmission (TM)
6 Clutch 7 ECU (controller)
10 Launch control switch Ve Vehicle

Claims (1)

a motor having an engine and a power generation function as a driving force source; a transmission provided on the output side of the driving force source; a clutch provided between the driving force source and the transmission; a battery connected to the
A control device for a hybrid vehicle configured to generate driving force by engaging the clutch when starting the vehicle from a stopped state by increasing the rotation speed of the engine with the clutch released,
A controller that controls the vehicle,
The controller is
In the stopped state, the motor is driven by the torque of the engine to generate power and the battery is charged;
stopping the power generation when at least one of the temperature of the motor and the temperature of the battery reaches a predetermined threshold;
A control device for a hybrid vehicle, wherein a driving torque is output from the engine and the motor when starting the vehicle from the stopped state.

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