JP2023045599A - Hybrid-vehicular control apparatus - Google Patents

Abstract

To provide a hybrid-vehicular control apparatus with a shock suppressed when starting an engine.SOLUTION: A hybrid-vehicular control apparatus is applied to a hybrid vehicle that includes an engine, a motor disposed in a power transmission path between the engine and a wheel, and a clutch disposed in the power transmission path between the engine and motor. In a case where the engine is required to start, the apparatus causes the motor to crank the engine by allowing the clutch to slip, followed by engaging the clutch. The apparatus includes: a first start control unit for starting combustion of the engine with the clutch slipping if a rotation speed of the motor is equal to or higher than a threshold in a case where the engine is required to start; and a second start control unit for starting combustion of the engine with the clutch engaged when the rotation speed of the motor is less than the threshold in a case where the engine is required to start.SELECTED DRAWING: Figure 3

Description

The present invention relates to a hybrid vehicle control device.

Some hybrid vehicles include an engine, a motor provided on a power transmission path between the engine and wheels, and a clutch provided between the engine and the motor on the power transmission path. When the engine is requested to start, the clutch is slipped and the engine is cranked by the motor, the clutch is engaged, and the engine is started (see, for example, Patent Document 1).

JP 2019-025985 A

As described above, the engine can be started early if combustion of the engine is started while the clutch is in the slipping state. However, in this case, the engine rotation speed increases beyond the motor rotation speed, and the rotation of the engine causes the rotation of the motor to increase, which may cause a shock to the hybrid vehicle.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a control device for a hybrid vehicle that suppresses a shock when the engine is started.

The above object is applied to a hybrid vehicle comprising an engine, a motor provided in a power transmission path between the engine and wheels, and a clutch provided between the engine and the motor in the power transmission path. A control device for a hybrid vehicle, wherein when there is a request to start the engine, the clutch is slipped, the engine is cranked by the motor, and then the clutch is engaged, when there is a request to start the engine. a first start control unit for starting combustion of the engine when the clutch is in a slip state when the rotational speed of the motor is equal to or greater than a threshold; (1) can be achieved by a control device for a hybrid vehicle including a second start control section for starting combustion of the engine when the clutch is engaged.

According to the present invention, it is possible to provide a control device for a hybrid vehicle that suppresses a shock when the engine is started.

FIG. 1 is a schematic configuration diagram of a hybrid vehicle. FIG. 2 is a timing chart showing an example of engine start control of a comparative example. FIG. 3 is a timing chart showing an example of engine start control according to this embodiment. FIG. 4 is a flowchart showing an example of engine start control executed by the ECU.

[Schematic configuration of hybrid vehicle]
FIG. 1 is a schematic configuration diagram of a hybrid vehicle 1. As shown in FIG. In the hybrid vehicle 1, a K0 clutch 14, a motor 15, a torque converter 18, and an automatic transmission 19 are provided in this order in a power transmission path from the engine 10 to the wheels 13. The engine 10 and the motor 15 are mounted on the hybrid vehicle 1 as drive sources. The engine 10 is, for example, a V-type 6-cylinder gasoline engine, but the number of cylinders is not limited to this, and may be an in-line engine or a diesel engine. K0 clutch 14 , motor 15 , torque converter 18 , and automatic transmission 19 are provided within transmission unit 11 . The transmission unit 11 and the left and right wheels 13 are drivingly connected via a differential 12 .

K0 clutch 14 is provided between engine 10 and motor 15 on the same power transmission path. The K0 clutch 14 is supplied with hydraulic pressure and becomes engaged to connect power transmission between the engine 10 and the motor 15 . The K0 clutch 14 is released when the supply of hydraulic pressure is stopped, and cuts off power transmission between the engine 10 and the motor 15 .

Motor 15 is connected to battery 16 via inverter 17 . The motor 15 functions as a motor that generates driving force for the vehicle in response to power supply from the battery 16, and also functions as a generator that generates electric power to charge the battery 16 in response to power transmission from the engine 10 and the wheels 13. also works. Electric power exchanged between the motor 15 and the battery 16 is regulated by the inverter 17 .

The inverter 17 is controlled by an ECU 40, which will be described later, and converts the DC voltage from the battery 16 into AC voltage, or converts the AC voltage from the motor 15 into DC voltage. In the power running operation in which the motor 15 outputs torque, the inverter 17 converts the DC voltage of the battery 16 into AC voltage to adjust the power supplied to the motor 15 . In the case of regenerative operation in which the motor 15 generates power, the inverter 17 converts AC voltage from the motor 15 into DC voltage to adjust the power supplied to the battery 16 .

The torque converter 18 is a fluid coupling having a torque amplifying function. The automatic transmission 19 is a stepped automatic transmission that switches the gear ratio in multiple stages by switching gear stages. The automatic transmission 19 is provided between the motor 15 and the wheels 13 on the power transmission path. A motor 15 and an automatic transmission 19 are connected via a torque converter 18 . The torque converter 18 is provided with a lockup clutch 20 that is engaged by being supplied with hydraulic pressure to directly connect the motor 15 and the automatic transmission 19 .

The transmission unit 11 is further provided with an oil pump 21 and a hydraulic control mechanism 22 . The hydraulic pressure generated by the oil pump 21 is supplied to the K0 clutch 14, the torque converter 18, the automatic transmission 19, and the lockup clutch 20 via the hydraulic control mechanism 22, respectively. The hydraulic control mechanism 22 includes hydraulic circuits for the K0 clutch 14, the torque converter 18, the automatic transmission 19, and the lockup clutch 20, and various hydraulic control valves for controlling the operating hydraulic pressures of these circuits. It is

The hybrid vehicle 1 is provided with an ECU (Electronic Control Unit) 40 as a control device for the vehicle. The ECU 40 is an electronic control unit that includes an arithmetic processing circuit that performs various kinds of arithmetic processing related to vehicle travel control, and a memory that stores control programs and data. The ECU 40 is an example of a control device for a hybrid vehicle, and functionally implements a first start control section and a second start control section, which will be described later in detail.

The ECU 40 controls driving of the engine 10 and the motor 15 . For example, the ECU 40 controls the torque and rotation speed of the engine 10 by controlling the throttle opening, ignition timing, and fuel injection amount of the engine 10 . The ECU 40 also controls the driving of the K0 clutch 14 , the lockup clutch 20 and the automatic transmission 19 through the control of the hydraulic control mechanism 22 .

The ECU 40 controls the rotation speed and torque of the motor 15 by controlling the inverter 17 and adjusting the amount of electric power exchanged between the motor 15 and the battery 16 . Although details will be described later, the ECU 40 controls the electric power supplied from the motor 15 to the battery 16 by the inverter 17 so that the motor braking torque in regenerative operation becomes a target value.

Signals from an ignition switch 31 , a crank angle sensor 32 , a motor speed sensor 33 and an accelerator opening sensor 34 are input to the ECU 40 . Crank angle sensor 32 detects the rotation speed of the crankshaft of engine 10 . A motor rotation speed sensor 33 detects the rotation speed of the output shaft of the motor 15 . The accelerator opening sensor 34 detects the accelerator pedal opening, which is the amount of depression of the accelerator pedal by the driver.

The ECU 40 drives the hybrid vehicle in one of the motor mode and the hybrid mode. In the motor mode, the ECU 40 releases the K0 clutch 14 and the power of the motor 15 drives the vehicle. In the hybrid mode, the ECU 40 engages the K0 clutch 14 to drive at least with the power of the engine 10 . Note that the hybrid mode includes a mode in which the vehicle runs only with the power of the engine 10, and a mode in which the motor 15 is powered and runs using both the engine 10 and the motor 15 as power sources.

The switching of the driving mode is performed based on the required driving force of the vehicle obtained from the vehicle speed and the degree of opening of the accelerator, the state of charge of the battery 16, and the like. For example, when the required driving force is relatively small and the SOC (State Of Charge), which indicates the amount of power remaining in the battery 16, is relatively high, the motor mode in which the engine 10 is stopped is selected to improve fuel efficiency. When the required driving force is relatively large or when the SOC of battery 16 is relatively low, at least the hybrid mode in which engine 10 is driven is selected.

For example, when the accelerator opening exceeds a predetermined value while the vehicle is running in the motor mode, the engine 10 is requested to be started. When there is a request to start the engine 10, the ECU 40 controls the hydraulic control mechanism 22 to shift the K0 clutch 14 from the released state to the slip state. This causes the motor 15 to start cranking the engine 10 . Further, although details will be described later, the ECU 40 starts combustion of the engine 10 when the K0 clutch 14 is in a slipping state or Combustion of the engine 10 is started. By starting the engine 10 in this way, the running mode is switched from the motor mode to the hybrid mode. It should be noted that starting combustion of the engine 10 means starting fuel injection from the fuel injection valve and starting ignition of the air-fuel mixture.

[Engine start control]
Next, before describing the engine start control of this embodiment, the engine start control of a comparative example will be described. FIG. 2 is a timing chart showing engine start control in a comparative example. FIG. 2 shows the engine speed [rpm], the motor speed [rpm], the state of the K0 clutch 14, and the combustion state of the engine 10. As shown in FIG. The engine speed is indicated by a dashed line, and the others are indicated by a solid line.

At time t0, the K0 clutch 14 is in the released state, the engine speed is 0, and combustion in the engine 10 is stopped. When there is a request to start the engine 10 after that, the K0 clutch 14 enters a slip state at time t1, and the output torque of the motor 15 increases by the torque for cranking the engine 10 . As a result, the cranking of the engine 10 is started by the motor 15 while the motor speed is maintained at the current speed, and the engine speed increases.

When combustion of the engine 10 starts at time t2 when the K0 clutch 14 is in a slip state and the engine speed is less than the motor speed, the rate of increase in the engine speed further increases. As a result, the engine speed exceeds the motor speed at time t3. Since the K0 clutch 14 is in a slip state, the motor rotation speed also temporarily increases due to the rotation of the engine 10, which may accelerate the hybrid vehicle 1 and cause a shock. After that, at time t4, the engine speed stabilizes and matches the motor speed, and the K0 clutch 14 is engaged. As described above, the phenomenon in which the engine speed exceeds the motor speed when the engine is started tends to occur when the motor speed is relatively low, for example, when the motor speed is equal to or less than a threshold value α described later.

FIG. 3 is a timing chart showing an example of engine start control according to this embodiment. 3 shows the engine speed [rpm], the motor speed [rpm], the state of the K0 clutch 14, and the combustion state of the engine 10, as in FIG. As in the comparative example, from time t0 when the K0 clutch 14 is in the released state and the engine 10 is stopped, the K0 clutch 14 is put in the slip state at time t1 by an engine start request, and cranking of the engine 10 is started. When the engine speed increases to the motor speed at time t2, the K0 clutch 14 is engaged, and combustion of the engine 10 starts at time t3. As described above, in the present embodiment, combustion of the engine 10 is started when the K0 clutch 14 is engaged, so it is possible to suppress the shock that occurs in the comparative example in which combustion of the engine 10 is started when the K0 clutch 14 is in a slipping state.

When the combustion of the engine 10 is started while the K0 clutch 14 is engaged as in this embodiment, it is preferable to start the combustion of the engine 10 immediately after the K0 clutch 14 is engaged. This is for suppressing start-up delay of the engine 10 . Further, when combustion of the engine 10 is started while the K0 clutch 14 is engaged as in the present embodiment, the hybrid vehicle 1 may vibrate due to an increase in the torque of the engine 10 . Therefore, the torque of the motor 15 may be decreased so as to offset the increase in the torque of the engine 10 in accordance with the timing of the start of combustion of the engine 10 .

As described above, the shock at engine start-up is likely to occur when the motor speed is relatively low. Therefore, in this embodiment, when the motor rotation speed is less than the threshold value α, the engine 10 starts combustion with the K0 clutch 14 engaged, and when the motor rotation speed is equal to or higher than the threshold value, the K0 clutch 14 is engaged. Combustion of the engine 10 is started in the slip state. Here, the threshold value α is set to an upper limit value at which the engine speed may exceed the motor speed when combustion of the engine 10 is started while the K0 clutch 14 is in a slipping state. Therefore, the engine 10 can be started early by starting the combustion of the engine 10 with the K0 clutch 14 in the slip state when the motor speed is equal to or higher than the threshold value which is less likely to be exceeded by the engine speed.

[Engine start control executed by ECU]
FIG. 4 is a flowchart showing an example of engine start control executed by the ECU 40. As shown in FIG. This control is repeatedly executed at predetermined intervals while the ignition is on. The ECU 40 determines whether there is a request to start the engine 10 (step S1). If No in step S1, this control ends.

In the case of Yes in step S1, the ECU 40 determines whether or not the engine 10 is being restarted after failure to start (step S2). Here, for example, the ECU 40 of this embodiment determines that the engine has failed to start and turns on the failure history flag when the engine speed cannot be increased to the speed at which the engine can be operated independently by cranking the motor 15. to The ECU 40 makes a determination in step S2 by referring to this flag. The ECU 40 immediately restarts the engine 10 by re-cranking the engine 10 when starting fails. At this time, the ECU 40 increases the cranking torque of the motor 15 by a predetermined value from the cranking torque before the failure.

If No in step S2, that is, if the engine 10 is started for the first time after a start request is issued, the ECU 40 determines whether or not the motor rotation speed is equal to or greater than the threshold value α (step S3).

In the case of Yes in step S3, the ECU 40 assumes that the above-described shock is unlikely to occur, and starts combustion in the engine 10 with the K0 clutch 14 in a slip state to start the engine 10 (step S4). As a result, the engine 10 can be started early. The state of the K0 clutch can be determined based on the absolute value of the difference between the engine speed and the motor speed. When this absolute value is less than a predetermined value which can be regarded as almost 0, the K0 clutch 14 is considered to be in the engaged state, and when this absolute value is greater than or equal to the predetermined value, it is considered that the K0 clutch 14 is in the slipping state. can be done. The process of step S4 is an example of the process executed by the first start control section.

If No in step S3, that is, if the motor rotation speed is less than the threshold value α, the ECU 40 starts combustion in the engine 10 with the K0 clutch 14 engaged to start the engine 10 (step S5). As a result, it is possible to suppress the occurrence of the shock described above. The process of step S5 is an example of the process executed by the second start control section.

If Yes in step S2, that is, if the engine 10 is restarted after a failure after a start request has been issued, the ECU 40 determines whether or not the motor rotation speed is equal to or greater than the threshold β ( step S6). Here, the threshold β is a value larger than the threshold α. As described above, the cranking torque is greater at the time of restart after a start failure than at the time of the initial start, so the engine speed is more likely to exceed the motor speed at the time of the restart than at the time of the first start. Therefore, when the engine is restarted after a failed start, it is determined whether or not the motor rotation speed is equal to or greater than the threshold value β, which is larger than the threshold value α.

In the case of Yes in step S6, the ECU 40 starts combustion in the engine 10 with the K0 clutch 14 slipping to start the engine 10 (step S4). Also in this case, the engine 10 can be started early. If No in step S6, the ECU 40 starts combustion in the engine 10 with the K0 clutch 14 engaged (step S5). In this case as well, the occurrence of the shock described above can be suppressed.

In the above embodiment, the case where the hybrid vehicle is controlled by the single ECU 40 has been exemplified, but the present invention is not limited to this. The control described above may be executed by a plurality of ECUs such as the clutch ECU.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and variations can be made within the scope of the gist of the present invention described in the scope of claims. Change is possible.

10 engine 14 K0 clutch 15 motor 40 ECU (first start control unit, second start control unit)

Claims (1)

applied to a hybrid vehicle comprising an engine, a motor provided in a power transmission path between the engine and wheels, and a clutch provided between the engine and the motor in the power transmission path; A control device for a hybrid vehicle that engages the clutch after slipping the clutch and cranking the engine by the motor when there is a request for starting,
a first start control unit for starting combustion of the engine with the clutch in a slip state when the number of revolutions of the motor is equal to or greater than a threshold value when there is a request to start the engine;
A control device for a hybrid vehicle, comprising: a second start control unit that starts combustion of the engine with the clutch engaged when the number of revolutions of the motor is less than the threshold value at the time of request to start the engine.

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