Hybrid Vehicles

Abstract

To provide a hybrid vehicle which is improved in acceleration responsiveness at the time of starting an engine.SOLUTION: The hybrid vehicle is provided with: an engine; a motor provided on a power transmission path extending from the engine to a driving wheel; a clutch provided on the power transmission path between the engine and the motor; an acceleration aperture detecting part that detects an acceleration aperture; and a control device that when the clutch is in a released state and start of the engine is requested, engages the clutch, by starting combustion of the engine while making the motor crank the engine through the clutch. The control device includes: a determining part that determines whether or not the accelerator aperture is a threshold or more when the start of the engine is requested; and an ignition time control part that makes a time of igniting the engine advance when the determination by the determining part is affirmative more than when the determination by the determining part is negative.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to hybrid vehicles. [Background technology]

[0002] There is a hybrid vehicle equipped with an engine, a motor provided on a power transmission path from the engine to the drive wheels, and a clutch provided on the power transmission path between the engine and the motor. In such a hybrid vehicle, when the clutch is in a disengaged state and there is a request to start the engine, the engine is cranked by the motor via the clutch, combustion in the engine starts, and the clutch is engaged. In this way, the engine is started (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-054165 Summary of the Invention [Problem to be solved by the invention]

[0004] When the accelerator pedal depression operated by the driver at engine start is large, i.e., when the driver's degree of acceleration request is large, if the engine torque increases slowly, there is a risk that acceleration responsiveness to the driver's request will decrease.

[0005] SUMMARY OF THE PRESENT EMBODIMENTS The present invention has an object to provide a hybrid vehicle with improved acceleration response when the engine is started. [Means for solving the problem]

[0006] The above object is to provide a vehicle engine having an engine, a motor provided on a power transmission path from the engine to drive wheels, a clutch provided on the power transmission path between the engine and the motor, an accelerator opening detection unit that detects an accelerator opening, and a control device that, when the clutch is in a released state and there is a request to start the engine, starts combustion in the engine while cranking the engine by the motor via the clutch and engages the clutch, wherein the control device has a determination unit that, when there is a request to start the engine, determines whether the accelerator opening is equal to or greater than a threshold value, and an ignition timing control unit that, when a positive determination is made by the determination unit, advances the ignition timing of the engine more than when a negative determination is made by the determination unit. a prediction unit that predicts a rotation speed of the motor when the clutch is engaged, and the ignition timing control unit advances the ignition timing as the predicted rotation speed of the motor becomes higher. This can be achieved with hybrid vehicles.

[0009] The engine may further include a temperature detection unit that detects a temperature of the engine, and the ignition timing control unit may advance the ignition timing as the temperature of the engine decreases.

[0010] The engine may further include an engine speed detection unit that detects a speed of the engine, and the ignition timing control unit may advance the ignition timing as the engine speed increases.

[0011] The ignition timing control unit may advance the ignition timing as the accelerator opening degree increases. Effect of the Invention

[0012] According to the present invention, it is possible to provide a hybrid vehicle with improved acceleration response when the engine is started. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram of a hybrid vehicle. [Diagram 2] FIG. 2 is a schematic diagram of the engine. [Diagram 3] FIG. 3 is a flowchart showing an example of engine start control executed by the ECU. [Figure 4] 4A to 4C are examples of maps that define the ignition timing. [Diagram 5] FIG. 5 is a flowchart showing an example of motor rotation speed prediction control. [Figure 6] FIG. 6A is a map that defines the relationship between the propeller shaft torque and the propeller shaft rotation speed for each accelerator opening, and FIG. 6B is a map that defines the relationship between the vehicle required torque and the motor rotation speed. [Figure 7] FIG. 7 is a map that defines the relationship between ignition timing and motor rotation speed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] [General configuration of hybrid vehicle] FIG. 1 is a schematic diagram of a hybrid vehicle 1. In the hybrid vehicle 1, a K0 clutch 14, a motor 15, a torque converter 18, and a transmission 19 are provided in this order in a power transmission path from an engine 10 to drive wheels 13. The engine 10 and the motor 15 are mounted as a driving source for running the hybrid vehicle 1. The engine 10 is, for example, a V6 gasoline engine, but the number of cylinders is not limited thereto, and may be an in-line gasoline engine or a diesel engine. The K0 clutch 14, the motor 15, the torque converter 18, and the transmission 19 are provided in a transmission unit 11. The transmission unit 11 and the left and right drive wheels 13 are drivingly connected via a propeller shaft 12a and a differential 12.

[0015] The K0 clutch 14 is provided between the engine 10 and the motor 15 on the power transmission path. The K0 clutch 14 is switched from a released state to an engaged state when hydraulic pressure is supplied, connecting the power transmission between the engine 10 and the motor 15. The K0 clutch 14 is switched to a released state when the hydraulic pressure supply is stopped, cutting off the power transmission between the engine 10 and the motor 15. The engaged state is a state in which both engagement elements of the K0 clutch 14 are connected and the engine 10 and the motor 15 have the same rotation speed. The released state is a state in which both engagement elements of the K0 clutch 14 are separated.

[0016] The motor 15 is connected to the battery 16 via an inverter 17. The motor 15 functions as a motor that generates driving force for the vehicle in response to power supplied 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 drive wheels 13. The electric power exchanged between the motor 15 and the battery 16 is adjusted by the inverter 17.

[0017] The inverter 17 is controlled by the ECU 100 described later, and converts the DC voltage from the battery 16 into an AC voltage, or converts the AC voltage from the motor 15 into a DC voltage. In the case of powering operation in which the motor 15 outputs torque, the inverter 17 converts the DC voltage of the battery 16 into an AC voltage and adjusts the power supplied to the motor 15. In the case of regenerative operation in which the motor 15 generates power, the inverter 17 converts the AC voltage from the motor 15 into a DC voltage and adjusts the power supplied to the battery 16.

[0018] The torque converter 18 is a fluid coupling having a torque amplifying function. The transmission 19 is a stepped automatic transmission that switches the gear ratio in multiple stages by switching the gear stage, but is not limited thereto and may be a continuously variable automatic transmission. The transmission 19 is provided between the motor 15 and the driving wheels 13 on the power transmission path. The motor 15 and the transmission 19 are connected via the torque converter 18. The torque converter 18 is provided with a lock-up clutch 20 that is supplied with hydraulic pressure and is engaged to directly connect the motor 15 and the transmission 19.

[0019] 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 transmission 19, and the lock-up clutch 20 via the hydraulic control mechanism 22. The hydraulic control mechanism 22 is provided with hydraulic circuits for the K0 clutch 14, the torque converter 18, the transmission 19, and the lock-up clutch 20, and various hydraulic control valves for controlling the operating hydraulic pressures thereof. It should be noted that a wet clutch may be provided instead of the torque converter 18.

[0020] The hybrid vehicle 1 is provided with an ECU (Electronic Control Unit) 100 as a control device for the vehicle. The ECU 100 is an electronic control unit including a calculation processing circuit that performs various calculation processes related to vehicle driving control, and a memory that stores control programs and data. The ECU 100 is an example of a control device for a hybrid vehicle, and functionally realizes a determination unit, an ignition timing control unit, and a prediction unit, which will be described in detail later.

[0021] The ECU 100 controls the operation of the engine 10 and the motor 15. Specifically, the ECU 100 controls the throttle opening, ignition timing, and fuel injection amount of the engine 10 to control the rotation speed and torque of the engine 10. The ECU 100 controls the inverter 17 to adjust the amount of electric power exchanged between the motor 15 and the battery 16, thereby controlling the rotation speed and torque of the motor 15. The ECU 100 also controls the operation of the K0 clutch 14, the lock-up clutch 20, and the transmission 19 through the control of the hydraulic control mechanism 22.

[0022] The ECU 100 receives signals from an ignition switch 71, a crank angle sensor 72, a motor revolution speed sensor 73, an accelerator opening sensor 74, an airflow meter 75, and a water temperature sensor 76. The crank angle sensor 72 detects the revolution speed of the crankshaft of the engine 10. The crank angle sensor 72 is an example of an engine revolution speed detection unit. The motor revolution speed sensor 73 detects the rotation speed of the output shaft of the motor 15. The motor revolution speed sensor 73 is an example of a motor revolution speed detection unit. The accelerator opening sensor 74 detects the accelerator pedal opening, which is the amount of depression of the accelerator pedal by the driver. The accelerator opening sensor 74 is an example of an accelerator opening detection unit. The airflow meter 75 detects the amount of intake air of the engine 10. The water temperature sensor 76 detects the temperature of the coolant that cools the engine 10. The temperature of the coolant correlates with the temperature of the engine 10, and the water temperature sensor 76 is an example of an engine temperature detection unit. The engine temperature detection unit may be, for example, an oil temperature sensor that detects the temperature of the lubricating oil that lubricates the engine 10, which is correlated with the temperature of the engine 10.

[0023] The ECU 100 runs the hybrid vehicle in either a motor mode or a hybrid mode. In the motor mode, the ECU 100 releases the K0 clutch 14 and runs the vehicle using the power of the motor 15. In the hybrid mode, the ECU 100 switches the K0 clutch 14 to an engaged state and runs the vehicle using at least the power of the engine 10. The hybrid mode includes a mode in which the vehicle runs using only the power of the engine 10, and a mode in which the motor 15 is powered and the vehicle runs using both the engine 10 and the motor 15 as power sources.

[0024] The driving mode is switched based on the vehicle's required driving force calculated from the vehicle speed and accelerator opening, and the state of charge of the battery 16. For example, when the required driving force is relatively small and the SOC (State Of Charge) indicating the amount of charge 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 the SOC of the battery 16 is relatively low, the hybrid mode in which the engine 10 is driven is selected.

[0025] In the hybrid mode, the ECU 100 executes intermittent operation control to automatically stop the engine 10 when a predetermined stop condition is satisfied, and to start the automatically stopped engine 10 when a predetermined start condition is satisfied. For example, in the hybrid mode, when the accelerator opening becomes zero, the ECU 10 automatically stops the engine 10 as the automatic stop condition is satisfied. In addition, when the accelerator opening becomes larger than zero, the ECU 10 automatically starts the engine 10 as the start condition is satisfied. When automatically stopping the engine 10, the ECU 100 releases the K0 clutch 14 to stop fuel injection. When automatically starting the engine 10, the ECU 100 cranks the engine 10 by the motor 15 via the K0 clutch 14 to start fuel injection and ignition, and then engages the K0 clutch 14.

[0026] [Engine outline] FIG. 2 is a schematic diagram of the engine 10. The engine 10 has cylinders 30, pistons 31, connecting rods 32, a crankshaft 33, an intake passage 35, an intake valve 36, an exhaust passage 37, and an exhaust valve 38. FIG. 2 shows only one of the multiple cylinders 30 of the engine 10. An air-fuel mixture is burned in the cylinder 30. A piston 31 is accommodated in each cylinder 30 so as to be capable of reciprocating, and is connected to a crankshaft 33, which is an output shaft of the engine 10, via a connecting rod 32. The connecting rod 32 converts the reciprocating motion of the piston 31 into the rotational motion of the crankshaft 33.

[0027] The intake passage 35 is connected to the intake port of each cylinder 30 via an intake valve 36. The exhaust passage 37 is connected to the exhaust port of each cylinder 30 via an exhaust valve 38. An air flow meter 75 and a throttle valve 40 that adjusts the amount of intake air are provided in the intake passage 35. A catalyst 43 for purifying exhaust gas is provided in the exhaust passage 37.

[0028] Each cylinder 30 is provided with an in-cylinder injection valve 41. The in-cylinder injection valve 41 injects fuel directly into the cylinder 30. Note that instead of or in addition to the in-cylinder injection valve 41, a port injection valve that injects fuel toward an intake port may be provided. Each cylinder 30 is provided with an ignition device 42 that ignites a mixture of intake air introduced through the intake passage 35 and fuel injected by the in-cylinder injection valve 41 by spark discharge.

[0029] When a start request is made for the engine 10 configured as described above with the K0 clutch 14 in a released state, the ECU 100 controls the engine 10, the K0 clutch 14, and the motor 15 as follows. The ECU 100 slips the K0 clutch 14 to increase the torque of the motor 15, thereby cranking the engine 10 by the motor 15 via the K0 clutch 14. When the engine speed reaches a predetermined value or more, the ECU 10 starts combustion in the engine 10, synchronizes the engine speed with the motor speed, and engages the K0 clutch 14. In this manner, the start of the engine 10 is completed. Here, when the accelerator opening operated by the driver at the time of starting the engine 10 is large, that is, when the degree of acceleration request by the driver is large, if the increase speed of the engine torque is slow, there is a risk that the acceleration responsiveness to the driver's request will decrease. Therefore, when there is a start request for the engine 10 and the accelerator opening is large, the ECU 100 advances the ignition timing of the engine 10 to increase the engine torque early. This will be described in detail below.

[0030] [Engine start control] FIG. 3 is a flowchart showing an example of engine start control executed by ECU 100. This control is repeatedly executed at a predetermined cycle with the ignition on. ECU 100 judges whether or not there is a request to start engine 10 (step S1). If the answer is No in step S1, this control ends. If the answer is Yes in step S1, ECU 100 judges whether or not the accelerator opening is equal to or greater than threshold value α (step S2). Threshold value α is set to a minimum value at which the degree of acceleration request by the driver is large and an advance in the ignition timing is required. Step S2 is an example of processing executed by the judgment unit.

[0031] If the result of step S2 is No, the degree of the driver's request for acceleration is deemed to be low, and the ECU 100 executes normal ignition start control (step S3). In the normal ignition start control, the ignition timing is controlled based on the coolant temperature, engine speed, and predicted motor speed, as will be described in detail later, to start the engine 10.

[0032] If the answer is Yes in step S2, the degree of acceleration request by the driver is deemed to be large, and the ECU 100 executes advanced ignition start control (step S4). In advanced ignition start control, the ignition timing is set to the more advanced side than in normal ignition start control, and the engine 10 is started. In advanced ignition start control, as in normal ignition start control, the ignition timing is controlled based on the coolant temperature, engine speed, and predicted motor speed. Step S4 is an example of a process executed by the ignition timing control unit.

[0033] In the normal ignition start control and the advanced ignition start control, the ECU 100 controls the ignition timing by referring to the maps of Figures 4A to 4C. Figures 4A to 4C are examples of maps that define the ignition timing. Figures 4A to 4C show the ignition timing when the accelerator opening degree at which the normal ignition start control is executed is less than the threshold value α, and the ignition timing when the accelerator opening degree at which the advanced ignition start control is executed is equal to or greater than the threshold value α.

[0034] FIG. 4A is an example of a map that defines the relationship between the ignition timing and the temperature of the coolant. The vertical axis indicates the ignition timing [deg], and the horizontal axis indicates the temperature of the coolant [°C]. As shown in FIG. 4A, in both cases where the accelerator opening is less than the threshold value α and greater than or equal to the threshold value α, the ignition timing is defined to be more advanced as the temperature of the coolant detected by the water temperature sensor 76 decreases. This is because the lower the temperature of the coolant, the more likely the engine torque is to decrease, and it is preferable to advance the ignition timing to compensate for this decrease in engine torque. In addition, when the accelerator opening is greater than or equal to the threshold value α, the ignition timing is defined to be more advanced than when the accelerator opening is less than the threshold value α. This is because when the accelerator opening is greater than or equal to the threshold value α, the degree of acceleration request by the driver is large, and it is preferable to increase the engine torque early from the viewpoint of acceleration responsiveness.

[0035] 4A, the rate of increase in the advance amount of the ignition timing relative to the decrease in the coolant temperature is set to be larger when the accelerator opening is equal to or greater than the threshold value α than when it is less than the threshold value α. This is because a large accelerator opening has a larger effect on the decrease in engine torque than a small accelerator opening, even if the amount of decrease in the coolant temperature is the same.

[0036] FIG. 4B is an example of a map that defines the relationship between the ignition timing and the engine speed. The vertical axis indicates the ignition timing [deg], and the horizontal axis indicates the engine speed [rpm]. As shown in FIG. 4B, in both cases where the accelerator opening is less than the threshold value α and greater than or equal to the threshold value α, the ignition timing is defined to be more advanced as the engine speed detected by the crank angle sensor 72 increases. This is because by advancing the ignition timing when the engine speed is high, the combustion speed can be increased, and the timing at which the cylinder pressure is maximized can be made to correspond to the optimal timing with high torque efficiency. Also, in FIG. 4B, when the accelerator opening is greater than or equal to the threshold value α, the ignition timing is defined to be more advanced than when the accelerator opening is less than the threshold value α. This is because, in this case as well, it is preferable to increase the engine torque earlier from the viewpoint of acceleration response.

[0037] In the map of FIG. 4B, when the engine speed is below a predetermined value, the ignition timing is constant regardless of the accelerator opening. This is because when the engine speed is low, the combustion speed is unlikely to increase and the engine torque is unlikely to increase even if the ignition timing is advanced. Also, when the engine speed is above this predetermined value, the rate of increase in the amount of ignition timing advance relative to an increase in engine speed is set to be greater when the accelerator opening is equal to or greater than the threshold value α than when the accelerator opening is below the threshold value α. Also, when the engine speed exceeds an even higher predetermined value, the ignition timing is limited to a constant value. This is because there is a risk of knocking occurring if the ignition timing is controlled to be advanced too much.

[0038] FIG. 4C is an example of a map that specifies the relationship between the ignition timing and the predicted motor rotation speed. The vertical axis indicates the ignition timing [deg], and the horizontal axis indicates the predicted motor rotation speed [rpm]. The predicted motor rotation speed is the motor rotation speed at the time of engagement of the K0 clutch 14 in the engine start control, which is predicted based on the accelerator opening, as will be described later in detail. As shown in FIG. 4C, in both cases where the accelerator opening is less than the threshold value α and is equal to or greater than the threshold value α, the ignition timing is specified to be more advanced as the predicted motor rotation speed is higher than a predetermined value. This is because the higher the predicted motor rotation speed, the larger the difference with the engine rotation speed before the engagement of the K0 clutch 14 is, and it is preferable to ensure the engine torque at the start of the engine 10. In FIG. 4C as well, when the accelerator opening is equal to or greater than the threshold value α, the ignition timing is specified to be more advanced than when the accelerator opening is less than the threshold value α. This is because in this case as well, it is preferable to increase the engine torque earlier from the viewpoint of acceleration response.

[0039] 4C, the rate of increase in the advance amount of the ignition timing relative to an increase in predicted motor speed is set to be larger when the accelerator opening is equal to or greater than threshold α than when the accelerator opening is less than threshold α. This is because, even if the increase in predicted motor speed is the same, it is necessary to ensure a larger rate of increase in engine torque when the accelerator opening is large than when it is small.

[0040] As described above, in the advance ignition start control, the ECU 100 controls the ignition timing to be more advanced than in the normal ignition start control. This makes it possible to increase the engine torque at the time of engine start in response to the driver's request for acceleration, improving acceleration responsiveness.

[0041] In the maps of Figures 4A to 4C, the ignition timing changes linearly, but is not limited to this, and may change in a curved or stepped manner. Also, without being limited to the above maps, the ignition timing may be calculated by an arithmetic expression using the accelerator opening, the coolant temperature, the engine speed, and the predicted motor speed as arguments. Also, in the above maps, when the accelerator opening is equal to or greater than the threshold value α, the ignition timing is specified regardless of the accelerator opening, but is not limited to this. When the accelerator opening is equal to or greater than the threshold value α, the ignition timing may be specified to be more advanced as the accelerator opening increases.

[0042] [Motor rotation speed predictive control] Next, motor rotation speed prediction control for calculating the predicted motor rotation speed described above will be described. The motor rotation speed prediction control is an example of a process executed by the prediction unit. Fig. 5 is a flowchart showing an example of the motor rotation speed prediction control. The motor rotation speed prediction control is executed when there is a request to start the engine 10 and the accelerator opening is equal to or greater than the threshold value α.

[0043] First, the ECU 100 calculates the accelerator opening at the time of a request to start the engine 10 and the rate of change in the accelerator opening per unit time based on the accelerator opening sensor 74 (step S11). Next, the ECU 100 predicts the accelerator opening at the time of engagement of the K0 clutch 14 (step S12). Specifically, the ECU 100 multiplies the time required from when a request to start the engine 10 is made until the K0 clutch 14 engages by the rate of change in the accelerator opening, and adds the current accelerator opening to the value obtained by this multiplication, thereby predicting the accelerator opening at the time of engagement of the K0 clutch 14.

[0044] Next, the ECU 100 predicts the torque required for the engine 10 when the K0 clutch 14 is engaged, based on the predicted accelerator opening (step S13). Specifically, the ECU 100 predicts the torque required for the engine 10 when the K0 clutch 14 is engaged, as follows.

[0045] The ECU 100 calculates the torque required for the hybrid vehicle 1 (hereinafter referred to as the vehicle required torque) from the predicted accelerator opening by referring to the map of FIG. 6A. FIG. 6A is a map that specifies the relationship between the propeller shaft torque and the propeller shaft rotation speed for each accelerator opening. The vertical axis indicates the propeller shaft torque [N·m], and the horizontal axis indicates the propeller shaft rotation speed [rpm]. The propeller shaft torque and the propeller shaft rotation speed are the torque and rotation speed of the propeller shaft 12a. The propeller shaft torque corresponds to the vehicle required torque. FIG. 6A shows the cases where the accelerator opening is 0%, 50%, and 100% as examples. Such maps for each gear are stored in the memory of the ECU 100.

[0046] As shown in Fig. 6A, the greater the accelerator opening, the greater the propeller shaft torque, i.e., the vehicle required torque. ECU 100 calculates the vehicle required torque based on the predicted accelerator opening and the current gear position. Next, ECU 100 multiplies the vehicle required torque by the current motor rotation speed to calculate the required output to hybrid vehicle 1 (hereinafter referred to as vehicle required output).

[0047] Next, an output required for the engine 10 (hereinafter referred to as the engine required output) is calculated by adding an output based on a charge / discharge request for the battery 16 (hereinafter referred to as the charge / discharge required output) to the vehicle required output. The charge / discharge required output is calculated as a positive value when there is a charge request for the battery 16, a negative value when there is a discharge request for the battery 16, and 0 when there is no charge / discharge request for the battery 16. Next, a torque required for the engine 10 (hereinafter referred to as the engine required torque) is calculated by dividing the engine required output by the current engine speed.

[0048] Next, the ECU 100 calculates a predicted motor rotation speed based on the engine required torque calculated in this manner (step S14). Specifically, the ECU 100 refers to the map in Fig. 6B to predict the motor rotation speed when the K0 clutch 14 is engaged from the engine required torque. Fig. 6B is a map that defines the relationship between the vehicle required torque and the motor rotation speed. The vertical axis represents the vehicle required torque [N·m], and the horizontal axis represents the motor rotation speed [rpm].

[0049] 6B, the equal power lines are indicated by dotted lines, the relationship between rotation speed and torque according to the gear shift is indicated by thin lines, and the operating lines of the actual hybrid vehicle 1 are indicated by thick lines. For example, when the current operating state of the hybrid vehicle 1 indicates the operating point P1, the gear shift is third gear, and the engine required torque is T2, the predicted gear shift when the K0 clutch 14 is engaged is fourth gear, and the predicted motor rotation speed is rotation speed R2. In this way, the motor rotation speed when the K0 clutch 14 is engaged can be predicted based on the accelerator opening.

[0050] Since the ignition timing is advanced based on the predicted motor rotation speed calculated as described above, the engine torque can be increased early in response to the predicted motor rotation speed, improving acceleration responsiveness.

[0051] Next, a modified example will be described. In the above embodiment, the advance amount of the ignition timing is calculated according to the predicted motor rotation speed. In contrast, in the modified example, the ECU 100 calculates the advance amount of the ignition timing according to the motor rotation speed detected by the motor rotation speed sensor 73 when there is a request to start the engine 10. Specifically, the ECU 100 calculates the advance amount of the ignition timing by referring to the map of FIG. 7. FIG. 7 is a map that specifies the relationship between the ignition timing and the motor rotation speed. The vertical axis indicates the ignition timing [deg], and the horizontal axis indicates the motor rotation speed [rpm]. FIG. 7 corresponds to FIG. 4C. In this case, as in the map of FIG. 4C, it is specified that the higher the motor rotation speed, the more the ignition timing is advanced, regardless of whether the accelerator opening is less than the threshold value α or equal to or greater than the threshold value α. In this modified example, unlike the above embodiment, there is no need to predict the motor rotation speed, and therefore the processing load of the ECU 100 is reduced.

[0052] In the above embodiment, the hybrid vehicle is controlled by a single ECU 100, but the present invention is not limited to this. For example, the above-mentioned control may be performed by a plurality of ECUs, such as an engine ECU for controlling the engine 10, a motor ECU for controlling the motor 15, a clutch ECU for controlling the K0 clutch 14, and a hybrid ECU for integrally controlling these ECUs. For example, the above-mentioned steps S1 and S2 may be performed by the hybrid ECU, and steps S3 and S4 may be performed by the engine ECU.

[0053] 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 are possible within the scope of the gist of the present invention described in the claims. [Explanation of symbols]

[0054] 10 Engine 14 K0 clutch 15 Motor 72 Crank angle sensor (engine speed detector) 73 Motor rotation speed sensor (motor rotation speed detection section) 74 Accelerator opening sensor (accelerator opening detection section) 76 Water temperature sensor (engine temperature detector) 100 ECU (judgment section, ignition timing control section, prediction section)

Claims

1. The engine, a motor provided on a power transmission path from the engine to a drive wheel; a clutch provided on the power transmission path between the engine and the motor; an accelerator opening detection unit that detects an accelerator opening; a control device that, when the clutch is in a released state and there is a request to start the engine, starts combustion in the engine while cranking the engine by the motor via the clutch, and engages the clutch, The control device includes: a determination unit that determines whether the accelerator opening is equal to or greater than a threshold when a request to start the engine is received; an ignition timing control unit that advances an ignition timing of the engine when a positive determination is made by the determination unit more than when a negative determination is made by the determination unit; a prediction unit that predicts a rotation speed of the motor when the clutch is engaged, A hybrid vehicle, wherein the ignition timing control unit advances the ignition timing as the predicted rotation speed of the motor becomes higher.

2. a temperature detection unit for detecting a temperature of the engine, 2. The hybrid vehicle according to claim 1, wherein the ignition timing control unit advances the ignition timing as the temperature of the engine decreases.

3. an engine speed detection unit that detects the engine speed; 3. The hybrid vehicle according to claim 1, wherein the ignition timing control unit advances the ignition timing as the engine speed increases.

4. 4. The hybrid vehicle according to claim 1, wherein the ignition timing control unit advances the ignition timing as the accelerator opening degree increases.

Images