Control device and control method for a hybrid vehicle

Abstract

A control device and a control method of a hybrid vehicle are provided. The control device controls a hybrid vehicle that includes an engine, a motor provided on a power transmission path between the engine and drive wheels, and a clutch provided in the power transmission path between the engine and the motor. The control device causes the engine to idle at a target engine speed and causes the motor to operate at a target motor speed in a released state of the clutch. The target motor speed is lower than the target engine speed when the engine idles in the released state of the clutch.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a control device and a control method for a hybrid vehicle. BACKGROUND

[0002] A control device for a hybrid vehicle is disclosed in Japanese Patent Application Publication No. 2020-111276. The hybrid vehicle is provided with an engine, a motor, a torque converter, and a transmission. The engine, the motor, the torque converter, and the transmission are arranged in this order.

[0003] The hybrid vehicle is further provided with a K0 clutch provided between the engine and the motor. The K0 clutch is capable of linking a crankshaft, which is an output shaft of the engine, and a rotor of the motor. That is, in an engaged state of the K0 clutch, the crankshaft and the rotor rotate as one. Here, a condition is assumed in which the engine rotational speed and the motor rotational speed are different in a released state of the K0 clutch. By switching the K0 clutch from the released state to the engaged state, the engine rotational speed and the motor rotational speed are the same.

[0004] The above-described control device switches the K0 clutch from the released state to the engaged state in a state in which the engine rotational speed and the motor rotational speed are controlled to be the same target rotational speed. Thereby, it is possible to suppress a sharp change in the motor rotational speed when the K0 clutch is switched from the released state to the engaged state. That is, it is possible to suppress a variation in driving force when the K0 clutch is engaged.

[0005] For example, there is a case in which the engine is idling in the released state of the K0 clutch. In this case, a higher engine rotational speed is sometimes required in order to stabilize combustion in the engine. The above-described control device, in conjunction with this, also increases the motor rotational speed. That is, in a case in which the engine is controlled in such a manner that combustion is stabilized, the power consumption in the motor increases according to the above-described control device. SUMMARY

[0006] According to an aspect of the present disclosure, there is provided a control device for a hybrid vehicle, the hybrid vehicle being provided with an engine, a motor provided on a power transmission path between the engine and a drive wheel, and a clutch provided between the engine and the motor in the power transmission path, the control device being provided with a processing circuit configured to, in a released state of the clutch, cause the engine to idle at a target engine rotational speed and cause the motor to operate at a target motor rotational speed, the target motor rotational speed being lower than the target engine rotational speed when the engine is idling in the released state of the clutch.

[0007] According to an aspect of the present disclosure, there is provided a control method of a hybrid vehicle that includes an engine, a motor provided on a power transmission path between the engine and a drive wheel, and a clutch provided in the power transmission path between the engine and the motor, the control method including: causing the engine to idle at a target engine rotation speed and causing the motor to operate at a target motor rotation speed in a released state of the clutch in accordance with the target engine rotation speed, the target motor rotation speed being lower than the target engine rotation speed when the engine idles in the released state of the clutch. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1 is a diagram showing a control device of a hybrid vehicle according to an embodiment and a hybrid vehicle controlled by the control device.

[0009] Figure 2 is a flowchart of a process of selecting a map from a normal map, a warm-up operation map, and a high-temperature restart map in a released state of a K0 clutch.

[0010] Figure 3 is a diagram showing the normal map.

[0011] Figure 4 is a diagram showing the warm-up operation map.

[0012] Figure 5 is a diagram showing the high-temperature restart map.

[0013] Figure 6 is a flowchart of a series of processes of switching from an EV travel mode to an engine travel mode by bringing the K0 clutch into an engaged state.

[0014] Figure 7 is a diagram showing an operation when switching from the EV travel mode to the engine travel mode in a case where the normal map is selected in the released state of the K0 clutch.

[0015] Figure 8 is a diagram showing an operation when switching from the EV travel mode to the engine travel mode in a case where the warm-up operation map is selected in the released state of the K0 clutch. DETAILED DESCRIPTION

[0016] Hereinafter, a control device of a hybrid vehicle according to an embodiment will be described with reference to the drawings.

[0017] <Configuration of Hybrid Vehicle 90>

[0018] Figure 1A control device 10 and a control target of the control device 10, that is, a hybrid vehicle (hereinafter, vehicle) 90 are shown. The vehicle 90 is provided with an engine 91 and a motor 82 as a drive source. The vehicle 90 is provided with a transmission unit 80 in a power transmission path from the engine 91 to a drive wheel 72. The transmission unit 80 and the drive wheel 72 are linked via a differential gear 71.

[0019] The transmission unit 80 is provided with the motor 82. The motor 82 is provided on the power transmission path between the engine 91 and the drive wheel 72. The motor 82 is connected to a power source via a converter. The motor 82 functions as a drive source that generates a driving force of the vehicle 90 by supply of electric power from the power source. In addition, the motor 82 can also function as a generator that generates electric power by power transmission from the engine 91 or the drive wheel 72.

[0020] The transmission unit 80 is provided with a K0 clutch 81. The K0 clutch 81 is located between the engine 91 and the motor 82 in the power transmission path. The K0 clutch 81 is operated by hydraulic pressure supplied from a hydraulic control mechanism 86 provided in the transmission unit 80. In an engaged state of the K0 clutch 81 in which the K0 clutch 81 is engaged, an output shaft, that is, a crankshaft 92 of the engine 91 is linked to a rotor of the motor 82. In a released state of the K0 clutch 81 in which the K0 clutch 81 is released, the crankshaft 92 is cut off from the rotor of the motor 82.

[0021] The transmission unit 80 is provided with a torque converter 83 and an automatic transmission 85. The automatic transmission 85 is located closer to the drive wheel 72 than to the motor 82 in the power transmission path. The automatic transmission 85 is linked to the motor 82 via the torque converter 83.

[0022] The torque converter 83 is provided with a pump impeller 83A on the input side and a turbine liner 83B on the output side. The pump impeller 83A rotates integrally with an input shaft to which power from the engine 91 and the motor 82 is input. The turbine liner 83B rotates integrally with an output shaft connected to the automatic transmission 85. In the torque converter 83, torque transmission via a fluid is performed between the pump impeller 83A and the turbine liner 83B.

[0023] In addition, the torque converter 83 is provided with a lock-up clutch 84 that can directly link the pump impeller 83A and the turbine liner 83B to rotate integrally with each other. The lock-up clutch 84 is operated by hydraulic pressure supplied from the hydraulic control mechanism 86. In the operating state of the lock-up clutch 84, there are a direct link state, a released state, and a slip state. The direct link state is a state in which the pump impeller 83A and the turbine liner 83B are directly linked via the lock-up clutch 84. The released state is a state in which the lock-up clutch 84 is released. The slip state is a state in which the lock-up clutch 84 slips.

[0024] In the vehicle 90, the running mode can be changed by switching between an EV (Electric Vehicle) running mode and an engine running mode. The EV running mode is a mode in which only the motor 82 is used as a drive source. The engine running mode is a mode in which the power of the engine 91 is transmitted to the drive wheels 72. In the EV running mode, the K0 clutch 81 is released. In the engine running mode, the K0 clutch 81 is engaged. The change of the running mode is performed by the control device 10 of the vehicle 90.

[0025] The control device 10 includes a so-called microcomputer having a CPU, a ROM, a RAM, and an input-output interface, and the like. The control device 10 performs signal processing by using the temporary storage function of the RAM and in accordance with a program stored in advance in the ROM. The control device 10 can control the engine 91, the motor 82, and the like.

[0026] The motor rotation speed sensor 14 is provided to the motor 82. The control device 10 can acquire the rotation speed of the motor 82, that is, the motor rotation speed, by the motor rotation speed sensor 14. The engine rotation speed sensor 20 is provided to the engine 91. The control device 10 can acquire the rotation speed of the engine 91, that is, the engine rotation speed, by the engine rotation speed sensor 20. The rotation speed refers to the number of rotations per 1 minute. The engine water temperature sensor 16 is provided to the engine 91. The control device 10 can acquire the water temperature of the engine 91, that is, the engine water temperature, by the engine water temperature sensor 16. The intake air temperature sensor 18 is provided to the engine 91. The control device 10 can acquire the temperature of the air taken into the engine 91, that is, the intake air temperature, by the intake air temperature sensor 18.

[0027] <Outline of the processing performed by the control device 10>

[0028] An idle operation of the engine 91 will be described. The idle operation refers to a state in which there is no output required to be taken out to the outside of the engine 91 and the engine rotation speed is constant. In other words, the idle operation means an operation of a state in which the shaft torque of the engine 91, that is, the net torque, is 0. The shaft torque of the engine 91 is a torque obtained by subtracting a torque consumed due to friction in the engine 91 from a torque generated by combustion in the engine 91. In other words, the shaft torque of the engine 91 is a torque taken out to the outside of the engine 91. In a case where the K0 clutch 81 is released and the shaft torque of the engine 91 is 0, the engine rotation speed is maintained constant. In a case where the K0 clutch 81 is released and the shaft torque of the engine 91 is negative, the engine rotation speed decreases. In a case where the K0 clutch 81 is released and the shaft torque of the engine 91 is positive, the engine rotation speed increases. Further, an idle operation in a state where the K0 clutch 81 is engaged is also considered.

[0029] As Figure 2As shown, with the K0 clutch 81 released, the control device 10 selects a mapping from normal mapping, preheating operation mapping, and high-temperature restart mapping. Here, these mappings specify the target engine speed and the target motor speed. The control device 10, according to the selected mapping, causes the engine 91 to idle and the motor 82 to operate. (Refer to...) Figures 3-5 These normal mappings, preheating operation mappings, and high-temperature restart mappings will be described later. When the K0 clutch 81 is released, as described above, the control device 10 controls the vehicle 90 in an EV driving mode that uses only the motor 82 as the drive source.

[0030] like Figure 6 As shown, when the requirement to switch the K0 clutch 81 from the released state to the engaged state (i.e., the switching requirement) is executed, the control device 10 performs a target speed matching process. The target speed matching process is the process of making the target engine speed, which is greater than the target motor speed, match the target motor speed. The switching requirement means that the engine driving mode is required to transmit power from the engine 91 to the drive wheel 72. After the engine speed matches the motor speed, the control device 10 switches the K0 clutch 81 from the released state to the engaged state. This suppresses fluctuations in the driving force when the K0 clutch 81 is engaged.

[0031] <Processes performed by control device 10 when clutch K0 81 is released>

[0032] With the K0 clutch 81 released, the control device 10 causes the engine 91 to idle at the target engine speed and the motor 82 to operate at the target motor speed. In other words, the control device 10 controls the engine 91 in a manner that matches the target engine speed. Similarly, the control device 10 controls the motor 82 in a manner that matches the target motor speed.

[0033] Reference Figure 2 This indicates that a specified mapping process is selected for the target engine speed and the target motor speed. Figure 2 The processing is repeated at predetermined intervals.

[0034] In step S200, control device 10 determines whether a preheating operation requirement exists. If a preheating operation requirement exists (step S200: Yes), control device 10 proceeds to step S202. In step S202, control device 10 selects... Figure 4 The preheating operation mapping is shown.

[0035] If there is no preheating operation requirement (step S200: No), the control device 10 proceeds to step S204. In step S204, the control device 10 determines whether a high-temperature restart requirement exists. If a high-temperature restart requirement exists (step S204: Yes), the control device 10 proceeds to step S206. Specifically, when the engine 91 is started, the control device 10 determines that a high-temperature restart requirement exists based on the condition that the intake air temperature is above a certain threshold and the engine coolant temperature is above a certain threshold (th temperature). In step S206, the control device 10 selects... Figure 5 The high-temperature restart mapping is shown. The high-temperature restart process is explained here. When the engine 91 stops at high ambient temperatures, fuel vaporization occurs. Under these conditions, fuel injection is difficult, resulting in unstable idling after the engine 91 starts. The high-temperature restart process promotes fuel injection by increasing the target engine speed. This stabilizes combustion.

[0036] If there is no requirement for high-temperature restart (step S204: No), control device 10 proceeds to step S208. In step S208, control device 10 selects... Figure 3 The typical mapping is shown.

[0037] After selecting a mapping in steps S202, S206, or S208, the control device 10 proceeds to step S210. In step S210, the control device 10 sets the target engine speed and target motor speed according to the selected mapping.

[0038] Next, refer to Figure 3 This indicates a typical mapping.

[0039] like Figure 3 As shown, in normal mapping, a constant target engine speed is set regardless of the shift position. Figure 3 In the example shown, the target engine speed is 800 rpm. The reason for setting a constant target engine speed regardless of shift position will be explained. Engine 91 is located upstream of motor 82, torque converter 83, and automatic transmission 85. K0 clutch 81 is located between engine 91 and motor 82. Therefore, when K0 clutch 81 is released, engine 91 is not affected by shift position. Therefore, with K0 clutch 81 released, a constant target engine speed is set regardless of shift position.

[0040] like Figure 3 As shown, in typical mapping, the target motor speed is set based on the shift position. Figure 3In the example shown, the target motor speed at the shift position of D (Drive) is 650. The D range is a shift position used during normal travel of the vehicle 90, and is a shift position in which the transmission 85 is automatically shifted in accordance with the speed of the vehicle 90. In the example shown, the target motor speed at the shift position of N (Neutral) is 700. The N range is a shift position in which power transmission of the gears in the transmission 85 is cut off. In the example shown, the target motor speed at the shift position of R (Reverse) is 650. The R range is a shift position used during reverse travel of the vehicle 90. Thus, the control device 10 sets the target motor speed based on the shift position, regardless of the operating state of the engine 91, when the engine 91 is idling in the released state of the K0 clutch 81. Figure 3 In the example shown, the target motor speed at the shift position of N (Neutral) is 700. The N range is a shift position in which power transmission of the gears in the transmission 85 is cut off. In the example shown, the target motor speed at the shift position of R (Reverse) is 650. The R range is a shift position used during reverse travel of the vehicle 90. Thus, the control device 10 sets the target motor speed based on the shift position, regardless of the operating state of the engine 91, when the engine 91 is idling in the released state of the K0 clutch 81. Figure 3 In the example shown, the target motor speed at the shift position of R (Reverse) is 650. The R range is a shift position used during reverse travel of the vehicle 90. Thus, the control device 10 sets the target motor speed based on the shift position, regardless of the operating state of the engine 91, when the engine 91 is idling in the released state of the K0 clutch 81.

[0041] As shown in FIG. 6, the target motor speed is lower than the target engine speed in the normal map used when the engine 91 is idling in the released state of the K0 clutch 81. Figure 3 As shown in FIG. 6, the target motor speed is lower than the target engine speed in the normal map used when the engine 91 is idling in the released state of the K0 clutch 81.

[0042] Next, the preheat operation map will be described with reference to FIG. 7. Figure 4 The preheat operation map will be described.

[0043] As shown in FIG. 8, the control device 10 sets the target engine speed based on the warm-up state of the engine 91, regardless of the shift position, when the engine 91 is warming up in the released state of the K0 clutch 81. As a variable that defines the warm-up state, the engine water temperature is used. The target engine speed set based on the warm-up state of the engine 91 is higher when the engine water temperature is lower. Figure 4 As shown in FIG. 9, the control device 10 sets the target motor speed based on the shift position and the warm-up state of the engine 91 when the engine 91 is warming up in the released state of the K0 clutch 81. The target motor speed set based on the shift position and the warm-up state of the engine 91 is higher when the engine water temperature is lower. As shown in FIG. 9, the relationship target motor speed (N range) > target motor speed (D range) ≥ target motor speed (R range) holds with respect to the engine water temperature. The target motor speed (D range) and the target motor speed (R range) are locally identical. In the example shown, the target motor speed (D range) is slightly shifted upward relative to the target motor speed (R range) for ease of illustration.

[0044] As shown in FIG. 9, the target motor speed is lower than the target engine speed in the preheat map used when the engine 91 is warming up in the released state of the K0 clutch 81, except for the target motor speed (N range) at the warm-up completion temperature Tn. Figure 4 As shown in FIG. 9, the target motor speed is lower than the target engine speed in the preheat map used when the engine 91 is warming up in the released state of the K0 clutch 81, except for the target motor speed (N range) at the warm-up completion temperature Tn. Figure 4 As shown in FIG. 9, the target motor speed is lower than the target engine speed in the preheat map used when the engine 91 is warming up in the released state of the K0 clutch 81, except for the target motor speed (N range) at the warm-up completion temperature Tn. Figure 4 As shown in FIG. 9, the target motor speed is lower than the target engine speed in the preheat map used when the engine 91 is warming up in the released state of the K0 clutch 81, except for the target motor speed (N range) at the warm-up completion temperature Tn.

[0045] As shown in FIG. 9, the target motor speed is lower than the target engine speed in the preheat map used when the engine 91 is warming up in the released state of the K0 clutch 81, except for the target motor speed (N range) at the warm-up completion temperature Tn. Figure 4 As shown in FIG. 9, the target motor speed is lower than the target engine speed in the preheat map used when the engine 91 is warming up in the released state of the K0 clutch 81, except for the target motor speed (N range) at the warm-up completion temperature Tn.

[0046] Next, with reference to Figure 5 The high-temperature restart map is explained.

[0047] The control device 10 executes the high-temperature restart processing in a case where it is determined that there is the above-described high-temperature restart request. The high-temperature restart processing includes processing of setting a target engine speed. As shown in FIG. 6, the target engine speed set in the high-temperature restart processing is higher when the engine water temperature is higher. Figure 5

[0048] The control device 10 sets a target motor speed based on the shift position and the engine water temperature when executing the high-temperature restart processing in the released state of the K0 clutch 81. As shown in FIG. 7, the target motor speed set in the high-temperature restart processing is higher when the engine water temperature is higher. As shown in FIG. 8, with respect to the engine water temperature, the relationship target motor speed (N range) > target motor speed (D range) = target motor speed (R range) holds. Figure 5 Figure 5

[0049] As shown in FIG. 9, the target motor speed is smaller than the target engine speed when the engine 91 is idling. Figure 5

[0050] <Processing executed by the control device 10 when switching the K0 clutch 81 from the released state to the engaged state>

[0051] With reference to FIG. 10, the processing executed by the control device 10 when switching the K0 clutch 81 from the released state to the engaged state is explained. The control device 10 starts the processing of FIG. 10 when the request to switch the K0 clutch 81 from the released state to the engaged state, i.e., the switching request, is executed. Figure 6 Figure 6

[0052] The control device 10 executes, in step S600, target speed matching processing of matching the target engine speed, which is larger than the target motor speed, with the target motor speed.

[0053] The control device 10 executes, in step S602, speed matching standby processing of standing by until the engine speed matches the target engine speed.

[0054] The control device 10 executes, in step S604, K0 clutch engagement processing of controlling the K0 clutch 81 to the engaged state.

[0055] ​​​​​​The control device 10 executes torque override processing in step S606. The torque override processing is processing that maintains the magnitude of the torque that is the sum of the engine shaft torque and the motor torque and changes the distribution of the engine shaft torque and the motor torque. Here, the engine shaft torque is the shaft torque of the engine 91, and the motor torque is the output torque of the motor 82.

[0056] When the processing in step S606 is completed, the control device 10 ends the present routine.

[0057] <Effects of the Present Embodiment>

[0058] Reference Figure 7 to explain the effects in the case where the switching request is executed in a state where the engine 91 is idling in accordance with the normal map.

[0059] First, the control device 10 idles the engine 91 in accordance with the target engine speed in the released state of the K0 clutch 81 and operates the motor 82 in accordance with the target motor speed. The target engine speed is greater than the target motor speed. Therefore, the engine speed is greater than the motor speed. The engine 91 is idling, and therefore the engine shaft torque is 0. In contrast, the motor torque is positive.

[0060] The control device 10 slightly increases the K0 clutch engagement rate from the released state of the K0 clutch 81 (i.e., a state where the K0 clutch engagement rate is 0) when the switching request is executed. Due to the target speed unification processing, the engine speed, which is greater than the motor speed, decreases from time T11 to time T12, and thereby approaches the motor speed. From time T11 to time T12, the engine shaft torque is negative.

[0061] At time T12, the engine speed and the motor speed are substantially identical. The control device 10 slightly increases the K0 clutch engagement rate from time T12 to time T13. Thereby, at time T13, the engine speed and the motor speed are identical. Thereby, the rotation synchronization flag, which indicates whether the engine speed and the motor speed are identical, changes from 0 to 1.

[0062] The control device 10 sharply increases the K0 clutch engagement rate to 1 from time T13 to time T14. The period from time T12, at which the engine speed and the motor speed are substantially identical, to time T14, at which the K0 clutch engagement rate is 1, is referred to as an engagement period.

[0063] The control device 10 executes torque override processing from time T14 to time T15. At time T15, the motor torque is 0. At time T15, the engine shaft torque is equal to the torque that was output from the motor 82 before the switching request was executed.

[0064] Reference Figure 8The effect in the case where the switching request is executed in a state where the engine 91 is idling in accordance with the warm-up operation map will be described. The change in engine speed, the change in motor speed, and the change in engine shaft torque according to the present embodiment are shown by a solid line. The change in engine speed, the change in motor speed, and the change in engine shaft torque according to the comparative example are shown by a one-dot chain line.

[0065] First, the control device 10 idles the engine 91 in accordance with the target engine speed in a released state of the K0 clutch 81, and operates the motor 82 in accordance with the target motor speed. Here, there is a warm-up operation request, so a higher target engine speed than the target engine speed of the normal map is set. In addition, a higher target motor speed than the target motor speed of the normal map is set. The target motor speed of the comparative example is the target motor speed of the normal map.

[0066] The control device 10 makes the engine speed coincide with the motor speed from time T21 to time T23. In order to make the engine speed coincide with the target motor speed, in the comparative example, the engine speed needs to be greatly reduced compared to the present embodiment. In the present embodiment, since a higher target motor speed is set before the switching request is executed, the amount of reduction in the engine speed is less compared to the comparative example. Here, even if the engine speed is made to coincide with the motor speed, the target motor speed is set to a size that is not affected by the poor warm-up operation of the engine 91.

[0067] Furthermore, the effect in the case where the switching request is executed in a state where the engine 91 is idling in accordance with the high-temperature restart map is the same as the effect shown in FIG. 9. Figure 8

[0068] <Effects of the Present Embodiment>

[0069] (1) The control device 10 idles the engine 91 in accordance with the target engine speed in a released state of the K0 clutch 81, and operates the motor 82 in accordance with the target motor speed. The target motor speed is smaller than the target engine speed. Therefore, compared to a configuration in which the motor 82 is operated in accordance with a target speed that coincides with the target engine speed, it is possible to reduce the power consumption in the motor 82.

[0070] (2) If the motor speed is changed, the driving force changes. When the switching request is executed, the target engine speed is made to coincide with the target motor speed. That is, even if the motor speed is not changed, it is possible to make the engine speed coincide with the motor speed. Thereby, it is possible to suppress the variation in driving force when the K0 clutch 81 is engaged.

[0071] ​(3) When the K0 clutch 81 is in the released state, the motor 82 is not affected by the engine 91. Therefore, the target motor speed can be freely set based on the shift position.

[0072] (4) When the K0 clutch 81 is in the released state, the engine 91 is not affected by the motor 82. Therefore, the target engine speed can be freely set based on the warm-up state of the engine 91 when the K0 clutch 81 is in the released state.

[0073] (5) When the engine water temperature is low, the warm-up of the engine 91 should be actively performed by raising the engine speed of the engine 91. In the above-described configuration, the target engine speed is higher when the engine water temperature is lower. Thus, the warm-up of the engine 91 can be appropriately performed.

[0074] (6) Sometimes, a shift request is made in the warm-up operation of the engine 91 in the released state of the K0 clutch 81. In the above-described configuration, the target engine speed is made to coincide with the target motor speed from a state in which the target motor speed is increased in anticipation of the target engine speed. Then, the K0 clutch 81 is controlled to the engaged state. Here, a comparative example can be considered in which the target engine speed is made to coincide with the target motor speed from a state in which the target motor speed is not increased in anticipation of the target engine speed. According to the above-described configuration, the change in the engine speed when the shift request is executed can be reduced compared to the comparative example. Therefore, in the above-described configuration, the warm-up of the engine 91 is less likely to be hindered compared to the comparative example. By controlling the K0 clutch 81 to the engaged state after the engine speed is made to coincide with the motor speed, the variation in the driving force at the engagement of the K0 clutch 81 can be suppressed.

[0075] (7) In the case where the engine 91 is stopped at a high outside air temperature, vaporization of fuel sometimes occurs. In this case, fuel is difficult to inject, and therefore unstable idling occurs after the start of the engine 91. In the above-described configuration, the control device 10 anticipates unstable idling in the case where the intake air temperature is equal to or higher than the threshold intake air temperature and the engine water temperature is equal to or higher than the threshold water temperature Th.

[0076] It is considered that the fuel pipe becomes hot when the engine water temperature is high. Therefore, it is considered that the higher the engine water temperature, the more likely vaporization of fuel occurs. In the above-described configuration, the target engine speed is higher when the engine water temperature is higher. By increasing the target engine speed, the injection of fuel can be further promoted. Thus, combustion can be stabilized.

[0077] (8) In some cases, switching request is made in the high-temperature restart processing in the released state of the K0 clutch 81. In the above-described configuration, the target engine speed is made to coincide with the target motor speed from the state in which the target motor speed is made to increase in such a manner that the target motor speed follows the target engine speed. Next, the K0 clutch 81 is controlled to the engaged state. Here, a comparative example can be considered in which the target engine speed is made to coincide with the target engine speed from the state in which the target motor speed is not made to increase in such a manner that the target motor speed follows the target engine speed. In the above-described configuration, compared with the comparative example, the change in the engine speed when the switching request is executed can be reduced. Therefore, in the above-described configuration, compared with the comparative example, it is difficult to hinder the high-temperature restart processing. By controlling the K0 clutch 81 to the engaged state after the engine speed and the motor speed are made to coincide, the variation in the driving force at the time of engagement of the K0 clutch 81 can be suppressed.

[0078] <Modification Example>

[0079] The present embodiment can be implemented as follows. The present embodiment and the following modification examples can be implemented in combination with each other within a range in which there is no technical contradiction.

[0080] In the above-described embodiment, the control device 10 selects the map from the normal map, the warm-up operation map, and the high-temperature restart map in the released state of the K0 clutch 81. However, this is only an example. When the engine 91 is idling in the released state of the K0 clutch 81, the target motor speed can also be only lower than the target engine speed.

[0081] In the above-described embodiment, Figure 3 The target engine speed and the target motor speed shown are only examples. For example, the target motor speed (D / R range) can be 650, and the target engine speed in the N range can be the same as the target motor speed, that is, 700. In this case, for example, when the engine 91 is idling in the state in which the shift position is in the D range, the target motor speed is lower than the target engine speed. In this case, the same effect as the above-described effect (1) can be obtained.

[0082] In the above-described embodiment, the target engine speed set based on the warm-up state of the engine 91 is higher when the engine water temperature is lower. However, this is only an example. For example, the target engine speed in the case where there is a warm-up request can also be a fixed value that is higher than the target engine speed in the case where there is no warm-up request.

[0083] In the above-described embodiment, the target engine speed set based on the warm-up state of the engine 91 is higher when the engine water temperature is lower. Figure 4 The warm-up operation map shown is only an example. For example, the target engine speed can also change in stages according to the engine water temperature.

[0084] In the above embodiment, the target motor speed set based on the shift position and the warm-up state of the engine 91 is higher when the engine water temperature is lower. Figure 4 The illustrated warm-up operation map is merely an example. For example, the target motor speed can also be changed in stages according to the engine water temperature.

[0085] In the above embodiment, the target engine speed set in the high-temperature restart processing is higher when the engine water temperature is higher. Figure 5 The illustrated high-temperature restart map is merely an example. For example, the target engine speed can also be changed in stages according to the engine water temperature.

[0086] In the above embodiment, the target motor speed set in the high-temperature restart processing is higher when the engine water temperature is higher. Figure 5 The illustrated high-temperature restart map is merely an example. For example, the target motor speed can also be changed in stages according to the engine water temperature.

[0087] In the above embodiment, the control device 10 has a CPU, a ROM, and a RAM, and executes software processing. However, this is merely an example. For example, the control device 10 can have a dedicated hardware circuit (e.g., ASIC, etc.) that processes at least a part of the software processing executed in the above embodiment. That is, the control device 10 can be configured in any one of (a) to (c) below. (a) The control device 10 has a processing device that executes all processing according to a program, and a program holding device such as a ROM that stores the program. That is, the control device 10 has a software execution device. (b) The control device 10 has a processing device that executes a part of the processing according to a program, and a program holding device. Further, the control device 10 has a dedicated hardware circuit that executes the remaining processing. (c) The control device 10 has a dedicated hardware circuit that executes all processing. Here, the software execution device and / or the dedicated hardware circuit can be plural. That is, the above processing can be executed by a processing circuitry having at least one of a software execution device and a dedicated hardware circuit. The software execution device and the dedicated hardware circuit included in the processing circuitry can be plural. The program holding device, i.e., the computer readable medium, includes all available media that can be accessed by a general-purpose or a dedicated computer.

Claims

1. A control device of a hybrid vehicle that has an engine, a motor provided on a power transmission path between the engine and a drive wheel, and a clutch provided in the power transmission path between the engine and the motor, the control device has a processing circuit, the processing circuit is configured to cause the engine to idle at a target engine speed and to cause the motor to operate at a target motor speed in a released state of the clutch, the target motor speed is lower than the target engine speed when the engine idles in the released state of the clutch, the processing circuit is configured to set the target engine speed based on a warm-up state of the engine regardless of a shift position when the engine warms up in the released state of the clutch, the target engine speed set based on the warm-up state of the engine is higher when the engine water temperature is lower, the processing circuit is configured to set the target motor speed based on a shift position and the warm-up state of the engine when the engine warms up in the released state of the clutch, the target motor speed set based on the shift position and the warm-up state of the engine is higher when the engine water temperature is lower, the processing circuit is configured to, when a request to switch the clutch to an engaged state, that is, a switching request, is executed in the warm-up operation of the engine in the released state of the clutch, execute: processing to make the target engine speed, which is higher than the target motor speed, coincide with the target motor speed; processing to wait until the engine speed coincides with the target engine speed; and processing to control the clutch to the engaged state.

2. The control device of the hybrid vehicle according to claim 1 the processing circuit is configured to, when a request to switch the clutch from the released state to the engaged state, that is, a switching request, is executed, execute: processing to make the target engine speed, which is higher than the target motor speed, coincide with the target motor speed; processing to wait until the engine speed coincides with the target engine speed; and processing to control the clutch to the engaged state.

3. The control device of the hybrid vehicle according to claim 1 or 2, the processing circuit is configured to set the target motor speed based on a shift position regardless of an operation state of the engine when the engine idles in the released state of the clutch.

4. A control device of a hybrid vehicle that has an engine, a motor provided on a power transmission path between the engine and a drive wheel, and a clutch provided in the power transmission path between the engine and the motor, the control device has a processing circuit, the processing circuit is configured to cause the engine to idle at a target engine speed and to cause the motor to operate at a target motor speed in a released state of the clutch, the target motor rotation speed is smaller than the target engine rotation speed when the engine is idling in the released state of the clutch, the processing circuitry is configured to execute a high-temperature restart process as a condition that an intake air temperature is equal to or higher than a threshold intake air temperature and an engine water temperature is equal to or higher than a threshold water temperature at the time of start of the engine, the high-temperature restart process includes a process of setting the target engine rotation speed, the target engine rotation speed set in the high-temperature restart process is higher when the engine water temperature is higher.

5. The control device of a hybrid vehicle according to claim 4, the processing circuitry is configured to set the target motor rotation speed based on a shift position and the engine water temperature when the high-temperature restart process is executed in the released state of the clutch, the target motor rotation speed set in the high-temperature restart process is higher when the engine water temperature is higher, the processing circuitry is configured to execute, when a request to switch the clutch to the engaged state, that is, a switching request is executed in the high-temperature restart process in the released state of the clutch: a process of making the target engine rotation speed, which is greater than the target motor rotation speed, coincide with the target motor rotation speed; a process of waiting until the engine rotation speed coincides with the target engine rotation speed; and a process of controlling the clutch to the engaged state.

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