Hybrid vehicle control device

Abstract

To provide a control device of a hybrid vehicle which enables improvement of regeneration efficiency.SOLUTION: A hybrid vehicle 10 includes: an engine 11; a motor 13; a battery 14 connected to the motor 13; a transmission 12 disposed between the engine 11 and the motor 13; and a rear tire 16 connected to the motor 13. The transmission 12 has: an input shaft 12a connected to the engine 11; an output shaft 12b connected to the motor 13; and a clutch mechanism 12c which causes the input shaft 12a and the output shaft 12b to engage with or discharge from each other. In one embodiment of the disclosure, a control device 1 of the hybrid vehicle 10 brings the clutch mechanism 12c included in the transmission 12 into an open state when regenerative power generation, in which rotational power transmitted from the rear tire 16 is utilized to cause the motor 13 to generate electric power, is performed.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a control device for a hybrid vehicle. [Background technology]

[0002] Patent Document 1 discloses a technique in which a throttle valve is controlled to open when a generator is generating regenerative power. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-183794 Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology disclosed in Patent Document 1, the generator is connected to the engine crankshaft via a belt mechanism, which means that when the generator generates electricity regeneratively, engine friction can prevent efficient power generation, potentially reducing regeneration efficiency.

[0005] Therefore, the present disclosure has been made to solve the above-mentioned problems, and has an object to provide a control device for a hybrid vehicle that can improve regeneration efficiency. [Means for solving the problem]

[0006] One aspect of the present disclosure made to solve the above problems is a control device for a hybrid vehicle having an engine, a generator, a battery connected to the generator, a transmission arranged between the engine and the generator, and wheels connected to the generator, wherein the transmission is provided with an input shaft connected to the engine, an output shaft connected to the generator, and a clutch mechanism that engages and disengages the input shaft and the output shaft, the control device being arranged in the order of the engine, the transmission, the generator, and the wheels from the engine side toward the wheels, and when regenerative power generation is performed to cause the generator to generate electricity using rotational power transmitted from the wheels, the clutch mechanism provided in the transmission is disengaged so that engine friction does not act on the generator. the transmission has an oil pump for maintaining oil pressure within the transmission, the oil pump is not connected to the power of the engine, and the oil pump is an electric oil pump; when an accelerator pedal of the hybrid vehicle is turned off to perform the regenerative power generation, the engine is stopped, and thereafter, before the accelerator pedal is turned on to engage the clutch mechanism, if the oil pressure is equal to or lower than a predetermined oil pressure, the oil pump is driven to maintain the oil pressure at a pressure higher than the predetermined oil pressure; It is characterized by:

[0007] According to this aspect, when regenerative power generation is performed, the clutch mechanism of the transmission is disengaged, disengaging the engine from the generator. Therefore, when regenerative power generation is performed, engine friction does not act on the generator, so the rotational power transmitted from the wheels is not consumed by engine friction but is efficiently recovered by the generator and used for regenerative power generation by the generator. Therefore, the generator can be efficiently made to generate power and charge the battery, thereby improving regeneration efficiency. Furthermore, by efficiently generating power and using the power charged in the battery through regenerative power generation to run the hybrid vehicle, fuel consumption in the hybrid vehicle can be reduced, thereby improving the fuel efficiency of the hybrid vehicle.

[0008] Furthermore, because the engine and generator can be decoupled using an existing transmission, there is no need for a dedicated part for decoupling the engine and generator, which simplifies the structure of the hybrid vehicle and reduces the cost and size of the hybrid vehicle. Furthermore, because the oil pump is not connected to the engine's power, it can be driven even when the engine is not running. Therefore, when regenerative power generation is performed and the engine is stopped, there is no need to run the engine to drive the oil pump to maintain hydraulic pressure in the transmission. Therefore, since the engine can be stopped even when regenerative power generation is performed for a long period of time, the amount of fuel consumed to run the engine can be reduced. Furthermore, since the oil pump is an electric oil pump, it is easy to control, and therefore the oil pump can be controlled with good responsiveness in accordance with the oil pressure in the transmission. Furthermore, when regenerative power generation is performed, the hydraulic pressure in the transmission can be maintained at the required pressure while the engine is stopped, which reduces the amount of fuel consumed to operate the engine while maintaining the hydraulic pressure in the transmission.

[0015] In the above aspect, it is preferable that a charging rate monitoring unit is provided that monitors the charging rate of the battery, and when the regenerative power generation is performed, if the charging rate of the battery monitored by the charging rate monitoring unit is equal to or higher than a predetermined charging rate, the clutch mechanism is brought into an engaged state.

[0016] According to this aspect, when regenerative power generation is performed, the clutch mechanism of the transmission is disengaged, and the engine and generator are disconnected. Therefore, when regenerative power generation is performed, engine friction does not act on the generator, and the rotational power transmitted from the wheels is not consumed by engine friction but is efficiently recovered by the generator and used for regenerative power generation by the generator. Therefore, the generator can be efficiently made to generate power and charge the battery, thereby improving regeneration efficiency. [Effects of the Invention]

[0017] According to the control device for a hybrid vehicle of the present disclosure, it is possible to improve regeneration efficiency. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a structural diagram of a control device for a hybrid vehicle according to a first embodiment. [Figure 2] FIG. 3 is a flowchart showing the contents of control performed in the first embodiment. [Figure 3] FIG. 4 is a diagram showing a state where regenerative power generation is performed in the first embodiment. [Figure 4] FIG. 1 is a diagram illustrating a problem in the prior art. [Figure 5] FIG. 3 is a structural diagram of a control device for a hybrid vehicle according to second and third embodiments. [Figure 6] FIG. 10 is a flowchart showing the contents of control performed in the second embodiment. [Figure 7] FIG. 10 is a flowchart showing the contents of control performed in the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of a control device for a hybrid vehicle according to the present disclosure will be described.

[0020] [First embodiment] First, the first embodiment will be described.

[0021] <Hybrid vehicle overview> First, an overview of a hybrid vehicle 10 in the hybrid vehicle control device 1 of this embodiment will be described. As shown in Fig. 1, the hybrid vehicle 10 has an engine 11, a transmission 12, a motor 13, a battery 14, front tires 15, rear tires 16, an ECU 17, and the like.

[0022] The engine 11 is a power source for the motor 13 and includes a crankshaft 11a. The crankshaft 11a is connected to an input shaft 12a of the transmission 12.

[0023] The transmission 12 is disposed between the engine 11 and the motor 13. The transmission 12 includes an input shaft 12a connected to the crankshaft 11a of the engine 11, an output shaft 12b connected to the motor 13, and a clutch mechanism 12c that engages and disengages the input shaft 12a and the output shaft 12b. The transmission 12 is an example of the "transmission" of the present disclosure.

[0024] The motor 13 is disposed closer to the rear tires 16 than the transmission 12, i.e., on the opposite side of the transmission 12 from the engine 11. The motor 13 functions as a motor that generates mechanical power from electrical energy, and as a generator that generates electrical energy from mechanical energy. That is, the motor 13 functions as a motor that generates power (i.e., mechanical power) for propelling the hybrid vehicle 10 using power (i.e., electrical energy) supplied from the battery 14. The motor 13 also functions as a generator that generates power (i.e., regenerative power generation) using the rotational power (i.e., mechanical energy) transmitted from the rear tires 16 and charges the power (i.e., electrical energy) into the battery 14. The motor 13 is an example of a "generator" in the present disclosure.

[0025] The battery 14 is connected to the motor 13. The battery 14 supplies power to the motor 13 to discharge, and receives power from the motor 13 to charge.

[0026] The front tires 15 are non-drive wheels, while the rear tires 16 are drive wheels and are connected to the motor 13 via an axle 21, a differential gear 19, and a drive shaft 18. The rear tires 16 are an example of the "wheels" of the present disclosure.

[0027] The ECU 17 is a control unit that controls the components of the hybrid vehicle 10 (for example, the engine 11, the transmission 12, the motor 13, etc.), and includes a central processing unit (CPU), various memories, an external input circuit, an external output circuit, etc.

[0028] <Control performed by the control device of a hybrid vehicle> Next, the control performed by the control device 1 for the hybrid vehicle, that is, the control performed by the ECU 17, will be described.

[0029] As shown in FIG. 4, conventionally, when the motor 13 performs regenerative power generation during deceleration of the hybrid vehicle 10, engine friction acts on the motor 13, which is connected to the engine 11 via the transmission 12. As a result, the rotational power (i.e., mechanical energy, indicated as "energy" in the figure) transmitted from the rear tires 16 is consumed by the engine friction, reducing the amount available for regenerative power generation by the motor 13, thereby reducing regenerative efficiency. Note that "engine friction" refers to friction loss that occurs between the components that make up the engine 11. Furthermore, "regenerative efficiency" refers to the power generation efficiency when the motor 13 performs regenerative power generation, i.e., the conversion efficiency when the rotational power is converted into electric power when the motor 13 performs regenerative power generation.

[0030] Therefore, in this embodiment, in order to improve regeneration efficiency, the ECU 17 performs control shown in Fig. 2 when the hybrid vehicle 10 is decelerating. As shown in Fig. 2, the ECU 17 determines whether or not a regeneration condition is met (step S1). Here, "the regeneration condition is met" means that, for example, an accelerator pedal (not shown) provided on the hybrid vehicle 10 is turned off or a brake pedal (not shown) provided on the hybrid vehicle 10 is turned on, causing the hybrid vehicle 10 to decelerate and meeting the condition for regenerative power generation by the motor 13.

[0031] Then, when the ECU 17 determines that the regeneration conditions are met (step S1: YES), it instructs the transmission 12 to set to N range (step S2), and operates a solenoid (not shown) provided in the transmission 12 to set the transmission 12 to N range (step S3).

[0032] In this way, when the hybrid vehicle 10 is decelerating, the transmission 12 is set to the N range, and as shown in Fig. 3, the clutch mechanism 12c of the transmission 12 is disengaged, and the input shaft 12a and the output shaft 12b of the transmission 12 are disengaged. This then interrupts the power transmission path between the engine 11 side and the motor 13 side of the transmission 12, and the engine 11 and the motor 13 are disengaged. In other words, the power transmission between the engine 11 and the motor 13 is physically interrupted. Note that "the clutch mechanism 12c is disengaged" means that, for example, if the clutch mechanism 12c includes multiple clutches (not shown), the multiple clutches are disengaged.

[0033] Next, the ECU 17 performs regenerative power generation (step S4). That is, the ECU 17 uses the rotational power transmitted from the rear tires 16 to cause the motor 13 to generate power, and causes the battery 14 to be charged with the power generated by the motor 13.

[0034] In this way, the engine 11 and the motor 13 are in a disconnected state, and the motor 13 performs regenerative power generation.

[0035] As described above, according to this embodiment, when regenerative power generation is performed by causing the motor 13 to generate electricity using the rotational power transmitted from the rear tires 16, the ECU 17 opens the clutch mechanism 12c of the transmission 12, as shown in FIG. 3.

[0036] In this way, when regenerative power generation is performed, the clutch mechanism 12c of the transmission 12 is disengaged, and the engine 11 and the motor 13 are disconnected. Therefore, when regenerative power generation is performed, engine friction does not act on the motor 13, and as shown in FIG. 3, the rotational power (i.e., mechanical energy, indicated as "energy" in FIG. 3) transmitted from the rear tires 16 is not consumed by engine friction but is efficiently recovered by the motor 13 and used for regenerative power generation by the motor 13. Therefore, the motor 13 can be efficiently caused to generate power and charge the battery 14, thereby improving regeneration efficiency. Furthermore, by efficiently performing regenerative power generation and using the power charged in the battery 14 to run the hybrid vehicle 10 (for example, EV running or HEV running), fuel (for example, gasoline) consumption in the hybrid vehicle 10 can be reduced, and the fuel efficiency of the hybrid vehicle 10 can be improved.

[0037] The applicant analyzed the regenerative efficiency and the fuel efficiency of the hybrid vehicle 10, and found that the invention of this embodiment improves both the regenerative efficiency and the fuel efficiency of the hybrid vehicle 10 compared to the conventional technology shown in FIG. 4 and the case where the throttle valve of the engine is opened as in Patent Document 1.

[0038] Furthermore, according to this embodiment, the engine 11 and the motor 13 can be decoupled using the existing transmission 12, eliminating the need for a dedicated component (such as a clutch) for decoupling the engine 11 and the motor 13. This simplifies the structure of the hybrid vehicle 10, thereby reducing the cost and size of the hybrid vehicle 10.

[0039] Second Embodiment Next, the second embodiment will be described with respect to the differences from the first embodiment.

[0040] 5, the control device 1 for a hybrid vehicle has an electric oil pump 31 for maintaining oil pressure in the transmission. The electric oil pump 31 is an electric oil pump and is not connected to the power of the engine 11.

[0041] In this embodiment, the ECU 17 performs the control shown in Fig. 6 when the hybrid vehicle 10 is decelerating. As shown in Fig. 6, when the accelerator pedal is released (step S101), the hybrid vehicle 10 decelerates and regenerative power generation is performed, the ECU 17 sets the transmission 12 (denoted as "T / M" in the drawing) to the N range and stops the engine 11 (step S102).

[0042] In this way, in this embodiment, when regenerative power generation is performed, the ECU 17 stops the engine 11. This makes it possible to reduce the amount of fuel consumed to operate the engine 11 when regenerative power generation is performed.

[0043] With the engine 11 stopped in this manner, the ECU 17 then determines whether the oil pressure in the transmission 12 is equal to or lower than a predetermined oil pressure P (e.g., 0.5 MPa) (step S103). The oil pressure in the transmission 12 is detected by a pressure sensor (not shown).

[0044] If the oil pressure in the transmission 12 is equal to or lower than the predetermined oil pressure P (step S103: YES), the ECU 17 drives the electric oil pump 31 (step S104) to increase the oil pressure in the transmission 12 to a pressure higher than the predetermined oil pressure P.

[0045] On the other hand, if the oil pressure in the transmission 12 is higher than the predetermined oil pressure P (step S103: NO), the ECU 17 stops the electric oil pump 31 (step S105).

[0046] In this way, the ECU 17 controls the electric oil pump 31 to maintain the oil pressure in the transmission 12 at a pressure higher than the predetermined oil pressure P.

[0047] Thereafter, when the accelerator pedal is turned ON (step S106) and the hybrid vehicle 10 accelerates, the ECU 17 sets the transmission 12 to the D range (step S107).

[0048] As described above, according to this embodiment, the control device 1 for a hybrid vehicle has the electric oil pump 31 for maintaining oil pressure in the transmission 12. The electric oil pump 31 is not connected to the power of the engine 11.

[0049] In this way, the electric oil pump 31 is not connected to the power of the engine 11, and can therefore be driven even when the engine 11 is not running. Therefore, when regenerative power generation is being performed and the engine 11 is stopped, there is no need to operate the engine 11 to drive the electric oil pump 31 in order to maintain oil pressure in the transmission 12. Therefore, since the engine 11 can be stopped even when regenerative power generation is being performed for a long period of time, the amount of fuel consumed to operate the engine 11 can be reduced.

[0050] Furthermore, the electric oil pump 31 is easy to control because it is electrically driven, and therefore can be controlled with good responsiveness in accordance with the hydraulic pressure in the transmission 12.

[0051] In addition, when regenerative power generation is performed, the ECU 17 stops the engine 11, and if the oil pressure in the transmission 12 is below a predetermined oil pressure P, it drives the electric oil pump 31 to control the oil pressure in the transmission 12 to maintain a pressure greater than the predetermined oil pressure P.

[0052] As a result, when regenerative power generation is performed, the oil pressure in the transmission 12 can be maintained at a required pressure while the engine 11 is stopped. Therefore, the oil pressure in the transmission 12 can be maintained while reducing the amount of fuel consumed to operate the engine 11.

[0053] Third Embodiment Next, the third embodiment will be described with respect to differences from the first and second embodiments.

[0054] 5, the control device 1 for the hybrid vehicle has a charging rate monitoring unit 32 that monitors the charging rate of the battery 14. The charging rate monitoring unit 32 is, for example, a charging rate sensor that detects the charging rate of the battery 14. Information (signal) on the charging rate of the battery 14 monitored (detected) by the charging rate monitoring unit 32 is input to the ECU 17.

[0055] In this embodiment, the ECU 17 performs the control shown in Fig. 7 when the hybrid vehicle 10 is decelerating. As shown in Fig. 7, when the accelerator pedal is released (step S201), the hybrid vehicle 10 decelerates, and regenerative power generation is performed, the ECU 17 checks the battery state (step S202). Specifically, in step S202, the ECU 17 checks the state of charge of the battery 14 monitored by the state of charge monitor 32.

[0056] Next, the ECU 17 determines whether or not there is a regeneration restriction determination (step S203). Specifically, in step S203, the ECU 17 determines whether or not it has been determined that the charge rate of the battery 14 is equal to or higher than a predetermined charge rate and therefore it is necessary to restrict regeneration power generation.

[0057] If a regeneration restriction determination is made (step S203: YES), specifically, if it is determined that the charge rate of the battery 14 is equal to or higher than a predetermined charge rate and therefore regenerative power generation needs to be restricted, the ECU 17 sets the transmission 12 to the D range and couples the power of the transmission 12 (step S204). Then, regenerative torque is output (step S205).

[0058] In this way, in this embodiment, when regenerative power generation is performed, if the charging rate of the battery 14 monitored by the charging rate monitoring unit 32 is equal to or higher than a predetermined charging rate, the ECU 17 sets the transmission 12 to D range and engages the clutch mechanism 12c of the transmission 12.

[0059] As a result, when regenerative power generation is performed while the battery 14 is fully charged, engine friction acts on the motor 13, and the rotational power transmitted from the rear tires 16 is consumed by the engine friction and is not used for regenerative power generation by the motor 13. Therefore, when the battery 14 is fully charged, it is possible to prevent the motor 13 from generating power to charge the battery 14. Therefore, the battery 14 is not overcharged, and the life of the battery 14 can be extended.

[0060] On the other hand, if there is no determination to limit regeneration (step S203: NO), specifically, if it is determined that there is no need to limit regenerative power generation because the charge rate of the battery 14 is less than the predetermined charge rate, the ECU 17 sets the transmission 12 to the N range and disconnects the power of the transmission 12 (step S204). Then, regenerative torque is output (step S205).

[0061] In this way, in this embodiment, when regenerative power generation is performed, if the charging rate of the battery 14 monitored by the charging rate monitoring unit 32 is less than a predetermined charging rate, the ECU 17 sets the transmission 12 to N range and puts the clutch mechanism 12c of the transmission 12 into an open state.

[0062] As a result, when regenerative power generation is performed, the clutch mechanism 12c of the transmission 12 is disengaged, and the engine 11 and the motor 13 are disconnected. Therefore, when regenerative power generation is performed, engine friction does not act on the motor 13, so the rotational power transmitted from the rear tires 16 is not consumed by engine friction but is efficiently recovered by the motor 13 and used for regenerative power generation by the motor 13. Therefore, the motor 13 can be efficiently made to generate power and charge the battery 14, thereby improving regenerative efficiency.

[0063] It should be noted that the above-described embodiments are merely examples and do not limit the present disclosure in any way. It goes without saying that various improvements and modifications are possible within the scope of the gist of the present disclosure. [Explanation of symbols]

[0064] 1. Hybrid vehicle control device 10 Hybrid vehicles 11 Engine 11a Crankshaft 12 Transmission 12a Input shaft 12b Output shaft 12c clutch mechanism 13 Motor 14 Battery 15 Front tires 16 rear tires 17 ECU 18 Drive shaft 19 Differential gear 21 axles 31 Electric oil pump 32 Charging rate monitoring section

Claims

1. The engine and A generator and a battery connected to the generator; a transmission disposed between the engine and the generator; a wheel connected to the generator; and In a control device for a hybrid vehicle, the transmission includes an input shaft connected to the engine, an output shaft connected to the generator, and a clutch mechanism that engages and disengages the input shaft and the output shaft, The engine, the transmission, the generator, and the wheels are arranged in this order from the engine side toward the wheels, When regenerative power generation is performed by using the rotational power transmitted from the wheels to cause the generator to generate electricity, the clutch mechanism provided in the transmission is opened to prevent engine friction from acting on the generator, an oil pump for maintaining oil pressure in the transmission; The oil pump is not connected to the power of the engine, The oil pump is an electric oil pump, When the accelerator pedal of the hybrid vehicle is released and the regenerative power generation is performed, Stopping the engine, and thereafter, when the accelerator pedal is turned ON and the clutch mechanism is brought into an engaged state, if the oil pressure is equal to or lower than a predetermined oil pressure, the oil pump is driven to control the oil pressure to be maintained at a pressure higher than the predetermined oil pressure. A control device for a hybrid vehicle, comprising:

2. 2. The hybrid vehicle control device according to claim 1, a charging rate monitoring unit that monitors the charging rate of the battery; When the regenerative power generation is performed, if the charging rate of the battery monitored by the charging rate monitoring unit is equal to or higher than a predetermined charging rate, the clutch mechanism is brought into an engaged state. A control device for a hybrid vehicle, comprising:

Images