Hybrid vehicle control device

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

[Technical field]

[0001] The present invention relates to a control device for a hybrid vehicle that has, as driving force sources, an engine and a motor having a power generating function. [Background technology]

[0002] Patent Document 1 describes a control device for a hybrid vehicle equipped with an engine and a motor having a power generating function as a driving force source. The control device described in Patent Document 1 is configured to generate power using the motor when starting from a stopped state with maximum driving torque, that is, when starting, a so-called launch start, and to assist the driving torque with the motor in addition to the engine torque when starting. More specifically, when the accelerator pedal is depressed with the brake pedal depressed, the driving torque of the engine is offset by the generating torque (negative torque) of the motor to generate power. Then, when the braking force becomes "0", the power generation by the motor is stopped, and the vehicle is started by the driving torque of the engine and the driving torque of the motor.

[0003] Patent Document 2 describes a clutch cooling device that is configured to prevent the starting clutch from seizing and ensure acceleration by using a coolant that is lower in temperature than normal when launching the vehicle, thereby lowering the temperature of the starting clutch in advance. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-078704 A [Patent Document 2] JP 2020-076482 A Summary of the Invention [Problem to be solved by the invention]

[0005] The control device described in the above-mentioned Patent Document 1 is configured to satisfy acceleration by outputting electric power generated by a motor as a driving 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 be reduced. If the motor and the battery are continuously controlled in such a state, the motor and the battery may become hot before the battery is fully charged or charged to a predetermined value, and the torque assist function of the motor may be reduced. In such a case, the output of the battery and the motor may be reduced, making it impossible to generate the required driving force, and thus the desired acceleration may not be obtained.

[0006] This invention has been devised with an eye on the above-mentioned technical problems, and aims to provide a control device for a hybrid vehicle that is capable of generating the required driving force while suppressing the temperature rise of the motor and battery. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention provides a vehicle equipped with an engine as a driving force source and a motor having a power generating function, a transmission provided on the output side of the driving force source, a clutch provided between the driving force source and the transmission, and a battery electrically connected to the motor, When there is a request to start the vehicle, A control device for a hybrid vehicle configured to increase the rotational speed of the engine with the clutch released, and to engage the clutch to generate driving force when starting the vehicle from a stopped state. The position is A controller for controlling the vehicle, the controller comprising: When there is a request to start the vehicle, In the vehicle stopped state, the motor is driven by the torque of the engine to generate power and charge the battery, and at least one of the temperature of the motor and the temperature of the battery is set to a predetermined value. The first threshold When the value is reached, Reduce the torque required for generating electricity. When the vehicle starts moving from the stopped state, By driving the motor with the power of the battery, The engine and the motor output driving torque. and reducing the driving torque of the motor after at least one of the temperature of the motor and the temperature of the battery reaches a second predetermined threshold value. It is configured as The second threshold value is determined based on a temperature at which the motor can output a maximum output, and the first threshold value is a temperature that is previously determined as a temperature lower than the second threshold value. It is characterized by the above. Effect of the Invention

[0008] According to the control device for a hybrid vehicle of the present invention, in the case of so-called launch start, the maximum torque is output from the engine and the motor to start the vehicle Ve. Specifically, when the vehicle is stopped, the engine drives the motor to generate electricity with the clutch released, and the battery is charged. When the temperature of the motor and the battery reaches a threshold, the generation is stopped. In this state, the SOC of the battery is increased, so the motor outputs a driving torque (assist torque) in addition to the engine to start the vehicle. This makes it possible to generate the driving force required by the driver when starting the vehicle, and as a result, the vehicle can be started with a desired acceleration. Also, as described above, when the temperature of the motor and the battery reaches a threshold, the generation is stopped. Therefore, it is possible to suppress the temperature (coil temperature) of the battery and the motor from rising excessively, and as a result, it is possible to suppress the output of the motor and the battery from decreasing. In other words, the vehicle can be started by generating the maximum power while protecting the components of the battery and the motor, and as a result, the desired acceleration can be obtained. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic diagram showing an example of a vehicle to which the present invention is applied; [Diagram 2] 4 is a time chart for explaining an example of control in the embodiment of the present invention. [Diagram 3] FIG. 13 is a schematic diagram showing another example of a vehicle to which the present invention is applied. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the accompanying drawings. Note that the following embodiment is merely an example of a specific embodiment of the present invention, and is not intended to limit the present invention.

[0011] FIG. 1 shows a schematic diagram of an example of a hybrid vehicle to be controlled in an embodiment of the present 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 an engine 1 to rear wheels 2. The hybrid vehicle (hereinafter, referred to as the vehicle) Ve shown in FIG. 1 includes the above-mentioned engine (ENG) 1 and a motor (MG) 3 capable of transmitting torque to the rear wheels 2 as a power source. 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 main components. The target vehicle Ve is not limited to the vehicle shown in FIG. 1, and may be a FF (front engine, front drive) vehicle, a MR (mid engine, rear drive) vehicle, or a RR (rear engine, rear drive) vehicle.

[0012] The engine 1 is an internal combustion engine such as a gasoline engine or a diesel engine, and is configured so that the adjustment of the output and the operating state 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, the on / off of ignition, and the ignition timing are electrically controlled. In the case of a diesel engine, the amount of fuel injected, the timing of fuel injection, or the opening of the throttle valve in an EGR [Exhaust Gas Recirculation] system are electrically controlled.

[0013] The motor 3 is disposed 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 engine torque output by the engine 1. In the vehicle Ve according to the embodiment of the present invention, the motor 3 also has a function as an electric motor that is driven by being supplied with electric power and outputs motor torque. That is, the motor 3 is a motor having a power generating function (so-called a motor generator), and is configured, for example, by a permanent magnet synchronous motor or an induction motor. The motor 3 is connected to a battery 4 via an inverter (not shown). Therefore, the motor 3 can be driven as a generator, and electricity generated at that time can be stored in the battery 4. In addition, 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.

[0014] The battery 4 is an electricity storage device that stores electricity generated by the motor 3, and is connected to the motor 3 so as to be able to send and receive electric power. Therefore, the electricity generated by the motor 3 as described above can be stored in the battery 4. Also, the electricity stored in the battery 4 can be supplied to the motor 3 to drive the motor 3. Note that the electricity storage device is not limited to the battery as shown in FIG. 1, and may be, for example, a capacitor.

[0015] As shown in Fig. 1, the automatic transmission 5 is disposed on the same axis as the engine 1 and on the output side of the motor 3, and is a transmission mechanism that transmits torque between the engine 1 and the motor 3 and the rear wheels 2 via a differential device 8. The automatic transmission 5 is essentially a mechanism that can appropriately change the ratio of the input rotation speed to the output rotation speed, and can set a plurality of gear ratios in a stepped manner. In the example shown in Fig. 1, the automatic transmission 5 is configured as a stepped automatic transmission that changes the transmission path of the drive torque by engaging or releasing an engagement mechanism (not shown) to perform gear shifting.

[0016] As shown in FIG. 1, a clutch 6 is provided between the automatic transmission 5 and the engine 1 and motor 3, which selectively transmits and cuts off torque. As is conventionally known, the clutch 6 is a friction-type engagement mechanism that is engaged and released by hydraulic pressure, for example, and is configured to be able to continuously change its torque capacity (transmission torque capacity). Specifically, the clutch 6 has friction plates connected to the rotating members on the engine 1 and motor 3 side, and friction plates connected to the rotating members on the rear wheels 2 side (both not shown). The clutch 6 can also be configured, for example, by a multi-plate clutch in which a plurality of friction plates are alternately arranged. By releasing the clutch 6, the engine 1 and motor 3 are separated from the drive system of the vehicle Ve. By engaging the clutch 6, the engine 1 and motor 3 are connected to the drive system of the vehicle Ve. That is, in the example shown in FIG. 1, the clutch 6 is configured to selectively transmit and cut off 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 steered wheels.

[0017] The ECU 7 corresponds to a "controller" in the embodiment of the present invention, and in the example shown in FIG. 1, it mainly controls the automatic transmission 5, the engine 1, the motor 3, the battery 4, and the clutch 6. The ECU 7 is an electronic control device mainly composed of, for example, a microcomputer, and receives data detected or calculated from various sensors. The input data includes, for example, an on / off signal of a launch control switch 10, an accelerator opening, a brake signal, a vehicle speed, a wheel speed, an engine speed, a motor speed, an engine torque, a motor torque, and a torque capacity of the clutch 6. The ECU 7 performs calculations using the various input data and pre-stored data and calculation formulas, and outputs the calculation results as control command signals to control the engine 1, the motor 3, the battery 4, the automatic transmission 5, the clutch 6, and the like.

[0018] As described above, the vehicle Ve configured as above outputs torque from the engine 1 and the motor 3 when the vehicle is launched, because the required driving force and the required acceleration become large. Specifically, when the vehicle is stopped and the launch control switch 10 (or an operation switch for a sports mode or the like) is turned on and the accelerator pedal is depressed, the engine speed and the engine torque are increased with the clutch 6 released. In addition, in order to charge the battery 4 at that time, the motor 3 is driven by the engine torque to generate electricity. As a result, large driving force and acceleration are generated by the engine torque and the motor torque. On the other hand, during the transitional period of the launch (particularly when the motor 3 is generating electricity and charging the battery 4), if the cooling performance of the battery 4 or the motor 3 is reduced, the temperature of the motor 3 or the battery 4 may rise excessively during generation and charging, and the output of each of them may decrease. In that case, it may not be possible to generate the acceleration and driving force required when the vehicle Ve is launched. Therefore, in the embodiment of the present invention, the vehicle is configured to suppress an excessive temperature rise of the motor 3 or the battery 4 at the time of launch.

[0019] 2 is a time chart showing an example of this control, in which the launch control switch 10 is turned on and the vehicle starts moving when it is stopped. Note that the thick solid line shows an example of the case where the control according to the embodiment of the present invention is executed, and the thin solid line shows an example of the case where this control is not executed (conventional example).

[0020] Specifically, first, when the launch control switch 10 (or an operating switch such as a sports mode switch) is turned on, the clutch 6 is released, and the accelerator is operated at a predetermined accelerator opening, the engine speed and engine torque start to increase (time t1). The motor 3 is driven by the engine torque, so that the motor 3 functions as a generator, and the generated electricity is charged to the battery 4. Therefore, at this time t1, the SOC of the battery 4 also starts to increase. Furthermore, as the motor 3 is driven and charging of the battery 4 begins, the temperature of the coil of the motor 3 increases, and the temperature of the battery 4 also increases.

[0021] Next, the increased temperature of the battery 4 reaches a threshold value (BATT threshold 1), or the temperature of the coil of the motor 3 reaches a threshold value (MG threshold 1) (at 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. Accordingly, the rate of increase in the SOC of the battery 4 decreases. Note that the respective threshold values ​​of the temperature of the battery 4 and the temperature of the coil of the motor 3 are set lower in anticipation of the rise in the temperatures of the battery 4 and the coil of the motor 3 when maximum power is output from the motor 3 at the time of starting (i.e., during acceleration).

[0022] Next, when the SOC of the battery 4 reaches a threshold value (SOC threshold value), the vehicle Ve is started (time t3). That is, the engine 1 and the motor 3 are able to output maximum power, and therefore, at time t3, the clutch 6 is engaged and the accelerator opening is increased to its maximum. This causes the engine torque and engine speed to increase further. The assist torque (driving torque) by the motor 3 also increases.

[0023] Next, the SOC of the battery 4 starts to decrease as a result of the drive torque being output from the motor 3. That is, the SOC decreases as power is supplied to the motor 3. Furthermore, as a result of the drive torque being output from the motor 3, the temperature of the battery 4 rises to a threshold value (BATT threshold 2), and the coil temperature of the motor 3 rises to a threshold value (MG threshold 2) (at time t4). The respective threshold values ​​of the temperature of the battery 4 and the temperature of the coil of the motor 3 are temperatures at which the motor 3 can output its maximum output, in other words, temperatures 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 their threshold values, so the drive torque of the motor 3 is decreased. This is to protect the components of the motor 3 and the battery 4.

[0024] Next, the operation of the embodiment of the present invention will be described. As described above, in the embodiment of the present invention, the vehicle Ve is configured to start by outputting maximum torque from the engine and the motor when launching. Specifically, when the vehicle is stopped, the engine 1 drives the motor 3 to generate electricity while the clutch 6 is released, and the battery 4 is charged. When the temperatures of the motor 3 and the battery 4 reach a threshold value, the generation of electricity is stopped. In this state, the SOC of the battery 4 is increased, so that the motor 3 outputs a driving torque (assist torque) in addition to the engine 1 to start the vehicle. This makes it possible to avoid or suppress inconveniences such as a small driving torque from the motor due to the SOC of the battery not increasing, as shown in the conventional example of FIG. 2. In other words, in the embodiment of the present invention, the driving force required by the driver can be generated when starting the vehicle, and as a result, the vehicle can be started with the desired acceleration.

[0025] Furthermore, as described above, in the embodiment of the present invention, the power generation is stopped when the temperature of the motor 3 or the battery 4 reaches a threshold value. Therefore, the temperature (coil temperature) of the battery 4 or the motor 3 can be prevented from rising excessively, and as a result, the output of the motor 3 or the battery 4 can be prevented from decreasing. In other words, the vehicle Ve can be started by generating maximum power while protecting the components of the battery 4 and the motor 3, and thus the desired acceleration can be obtained.

[0026] Although the embodiment of the present invention has been described above, the present invention is not limited to the above-mentioned examples, and may be modified as appropriate within the scope of achieving the object of the present invention. In the above-mentioned embodiment, the vehicle Ve to be the subject of the description is a vehicle having an engine 1 and one motor 3, but the vehicle Ve may have a plurality of motors, not limited to one. FIG. 3 shows an example of such a hybrid vehicle. In the example shown here, the motor 11 is connected to the front wheels 12 so as to be capable of transmitting power. That is, the example shown in FIG. 3 is an example of a four-wheel drive vehicle (referred to as 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.

[0027] Like the above-mentioned motor 3, the motor 11 may be a motor having a power generating function (so-called motor generator). The motor 11 is connected to the battery 4 via an inverter (not shown). The motors 3 and 11 are further connected via the inverter so as to be able to exchange power with each other. Therefore, for example, it is possible to directly supply electricity generated by the motor 3 to the motor 11, and have the motor 11 output motor torque. [Explanation of symbols]

[0028] 1 Engine (ENG) 3,11 Motor (MG) 4 Battery (BATT) 5 Automatic transmission (TM) 6. Clutch 7 ECU (controller) 10 Launch control switch Vehicle

Claims

[Claim 1] The vehicle comprises an engine as a driving force source and a motor having a power generating function, a transmission provided on an output side of the driving force source, a clutch provided between the driving force source and the transmission, and a battery electrically connected to the motor, A control device for a hybrid vehicle configured to increase a rotation speed of the engine with the clutch released when there is a request to start the vehicle, and to engage the clutch to generate a driving force when starting the vehicle from a stopped state, A controller for controlling the vehicle, The controller: When there is a request to start the vehicle, while the vehicle is stopped, the motor is driven by the torque of the engine to generate power and charge the battery; When at least one of a temperature of the motor and a temperature of the battery reaches a predetermined first threshold, a power generation torque for the power generation is reduced; When starting the vehicle from the stopped state, the motor is driven by electric power from the battery, thereby outputting a driving torque from the engine and the motor; a drive torque of the motor is reduced after at least one of a temperature of the motor and a temperature of the battery reaches a predetermined second threshold; The second threshold value is determined based on a temperature at which the motor can output a maximum output, and the first threshold value is a temperature that is determined in advance as a temperature lower than the second threshold value. A control device for a hybrid vehicle.

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