Hybrid vehicles

Abstract

To provide a hybrid vehicle which enables power generation (P-range power generation) using a motor generator in a P (parking) range, and which, when switching to an R (backward traveling) range is performed (when shift operation is performed) during the P-range power generation, can prevent the occurrence of a delay in response to the shift operation.SOLUTION: In a hybrid vehicle 1, a manual valve 80 allows oil to be supplied to a forward clutch 32 when a P range is selected. When an SOC of a high-voltage battery 73 decreases to a predetermined value or lower in the P range, an HEV-CU 70 or the like disengages an output clutch 61, engages the forward clutch 32, and causes an engine 10 to operate to drive a motor generator 40 as a generator. When an R range is selected while power is being generated in the P range, the HEV-CU 70 or the like drives an electric oil pump 36, and supplies the oil to the output clutch 61 through an oil passage 39.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a hybrid vehicle. Background Art

[0002] In recent years, hybrid vehicles (HEVs), which can effectively improve the fuel consumption rate (fuel efficiency) of vehicles by using both an engine and an electric motor, have been widely put into practical use.

[0003] For example, Patent Document 1 discloses that a crankshaft of an engine is connected to one end of a primary shaft (primary pulley) of a continuously variable transmission via a torque converter including a lock-up clutch and a forward / reverse switching mechanism including a forward clutch and a reverse brake, the other end of the primary shaft of the continuously variable transmission is connected to an input / output shaft of a motor generator (electric motor), and a secondary shaft (secondary pulley) of the continuously variable transmission is connected to front wheels via an output clutch. Prior Art Documents Patent Documents

[0004] Patent Document 1 Japanese Unexamined Patent Publication No. 2016-61348 Summary of the Invention Problems to be Solved by the Invention

[0005] By the way, in the hybrid vehicle having the configuration described in Patent Document 1, when the state of charge (SOC) of a high-voltage battery decreases due to power consumption of electrical components such as an air conditioner during parking in the P (parking) range, there is a demand to drive the motor generator with the engine to generate electric power (to charge the high-voltage battery). That is, there is a demand to generate power in the P range (hereinafter referred to as "P-range power generation").

[0006] However, in the hybrid vehicle described in Patent Document 1, both the forward clutch and the reverse brake are released in the P range, so the engine cannot drive the motor generator and therefore cannot generate electricity (P range power generation).

[0007] Therefore, in order to enable power generation in P range, if, for example, the forward clutch is engaged, the reverse brake is released, and the output clutch is also released in P range, that is, if the engine can drive the motor generator and no driving force is transmitted to the front wheels, then when the vehicle is switched from P range to R (reverse) range (when the shift is performed) during power generation in P range, the number of clutches that need to be engaged (oil supply) (e.g., the output clutch) increases (to two systems) compared to when the vehicle is switched from P range to R range (or D (drive) range) under normal conditions (i.e., when power generation in P range is not performed), which may cause a delay in response to the shift operation. This may cause discomfort to the driver.

[0008] The present invention was made to solve the above problems, and aims to provide a hybrid vehicle in which the engine is connected to one end of the primary shaft of a continuously variable transmission via a forward / reverse switching mechanism including a forward clutch and a reverse brake, the other end of the primary shaft of the continuously variable transmission is connected to a motor generator, and the secondary shaft of the continuously variable transmission is connected to the drive wheels via an output clutch, and which enables power generation using the motor generator in the parking (P) range (P range power generation), and which prevents a delay in response to a shift operation even if the vehicle is switched to the R range (or D range) (even if a shift operation is performed) during P range power generation. [Means for solving the problem]

[0009] A hybrid vehicle according to one aspect of the present invention is a hybrid vehicle in which an engine is connected to one end of the primary shaft of a continuously variable transmission via a forward / reverse switching mechanism including a forward clutch and a reverse brake, the other end of the primary shaft of the continuously variable transmission is connected to a motor generator, and the secondary shaft of the continuously variable transmission is connected to the drive wheels via an output clutch, and the hybrid vehicle includes a mechanical oil pump driven by the engine and motor generator to pressurize and discharge oil, an electric oil pump driven by an electric motor to discharge oil via a check valve that opens when the discharge pressure is higher than the discharge pressure of the mechanical oil pump, a manual valve that switches the supply of oil to the forward clutch and reverse brake according to the shift operation state, and the electric oil pump and output The vehicle comprises an oil passage communicating with the clutch or reverse brake, and a control unit that controls the drive of the engine, motor generator, and electric oil pump, as well as the engagement and disengagement of the forward clutch, reverse brake, and output clutch. A manual valve is configured to supply oil to the forward clutch when the parking range is selected. The control unit is characterized in that, when the charge level of the high-voltage battery falls below a predetermined value in the parking range, it disengages the output clutch, engages the forward clutch, and operates the engine to drive the motor generator as a generator. When the motor generator is being generated in the parking range and the reverse driving range is selected, it drives the electric oil pump and supplies oil to the output clutch or reverse brake through the oil passage. [Effects of the Invention]

[0010] According to the present invention, in a hybrid vehicle in which the engine is connected to one end of the primary shaft of a continuously variable transmission via a forward / reverse switching mechanism including a forward clutch and a reverse brake, the other end of the primary shaft of the continuously variable transmission is connected to a motor generator, and the secondary shaft of the continuously variable transmission is connected to the drive wheels via an output clutch, it is possible to generate electricity using the motor generator in the parking (P) range (P range generation), and even if the vehicle is switched to the R range (or D range) during P range generation (even if a shift operation is performed), it is possible to prevent a delay in response to the shift operation. [Brief explanation of the drawing]

[0011] [Figure 1] This is a block diagram showing the configuration of a hybrid vehicle according to the embodiment. [Figure 2] This diagram shows the configuration of the hydraulic circuit that supplies hydraulic pressure to the forward / reverse switching mechanism (forward clutch, reverse brake) and the output clutch (P range, power generation state). [Figure 3] This diagram shows the configuration of the hydraulic circuit that supplies hydraulic pressure to the forward / reverse switching mechanism (forward clutch, reverse brake) and the output clutch (in the R range state). [Figure 4] This is an engagement table showing the engagement and release states of the lock-up clutch, forward clutch, output clutch, transfer clutch, and reverse brake in each of the following states: P range, P range generator, R range, and D range. [Figure 5] This flowchart (Part 1) shows the processing procedure for power generation in the P range in a hybrid vehicle according to the embodiment. [Figure 6] This flowchart (part 2) shows the processing procedure for power generation in the P range in a hybrid vehicle according to the embodiment. [Modes for carrying out the invention]

[0012] Preferred embodiments of the present invention will be described in detail below with reference to the drawings. In the drawings, the same or corresponding parts will be denoted by the same reference numerals. In addition, in each drawing, the same elements will be denoted by the same reference numerals, and redundant explanations will be omitted.

[0013] First, the configuration of the hybrid vehicle 1 according to the embodiment will be explained using Figures 1 to 4 together. Figure 1 is a block diagram showing the configuration of the hybrid vehicle 1. Figure 2 is a diagram showing the configuration of the hydraulic circuit that supplies hydraulic pressure to the forward / reverse switching mechanism 30 (forward clutch 32, reverse brake 33) and the output clutch 61 (P range power generation state), and Figure 3 is a diagram showing the configuration of the same hydraulic circuit (R range state). Figure 4 is an engagement table showing the engagement and release states of the lock-up clutch 24, forward clutch 32, output clutch 61, transfer clutch 64, and reverse brake 33 in the P range, P range power generation, R range, and D range states.

[0014] The engine 10 can be of any type, but for example, it is a horizontally opposed, direct-injection, four-cylinder gasoline engine. In the engine 10, air drawn in from the air cleaner (not shown) is restricted by an electronically controlled throttle valve located in the intake manifold, passes through the intake manifold, and is drawn into each cylinder of the engine 10. Here, the amount of air drawn in from the air cleaner is detected by an airflow meter 83. Furthermore, the throttle valve is equipped with a throttle opening sensor that detects the opening degree of the throttle valve. Each cylinder is fitted with an injector that injects fuel. Each cylinder is also fitted with a spark plug that ignites the fuel-air mixture, and an igniter-integrated coil that applies a high voltage to the spark plug. In each cylinder of the engine 10, the fuel-air mixture of the drawn-in air and the fuel injected by the injector is ignited by the spark plug and combusted. The exhaust gas after combustion is discharged through the exhaust pipe.

[0015] In addition to the airflow meter 83 and throttle position sensor mentioned above, a cam angle sensor is mounted near the camshaft of the engine 10 to determine which cylinder it is. A crank angle sensor 84 is also mounted near the crankshaft 15 of the engine 10 to detect the rotational position (rotational speed) of the crankshaft 15. These sensors are connected to the engine control unit (hereinafter referred to as "ECU") 71, which will be described later. Various other sensors, such as a water temperature sensor for detecting the temperature of the engine 10's coolant, are also connected to the ECU 71.

[0016] A continuously variable transmission (CVT) 50 is connected to the crankshaft 15 of the engine 10 via a torque converter 20, which has a clutch function and a torque amplification function, and a forward / reverse switching mechanism 30, which converts and outputs the driving force from the engine 10.

[0017] The torque converter 20 mainly consists of a pump impeller 21, a turbine runner 22, and a stator 23. The pump impeller 21, connected to the crankshaft 15, generates an oil flow, and the turbine runner 22, positioned opposite the pump impeller 21, receives power from the engine 10 via the oil and drives the turbine shaft 25. The stator 23, located between the two, rectifies the discharge flow (return) from the turbine runner 22 and returns it to the pump impeller 21, thereby generating a torque amplification effect.

[0018] Further, the torque converter 20 includes a lock-up clutch 24 that directly connects an input and an output. When the lock-up clutch 24 is not engaged (in a non-lock-up state), the torque converter 20 torque-amplifies the driving force of the engine 10 and transmits the amplified driving force to the continuously variable transmission 50; when the lock-up clutch 24 is engaged (during lock-up), the torque converter 20 directly transmits the driving force of the engine 10 to the continuously variable transmission 50. Note that when generating electricity in the P range (parking range), the lock-up clutch 24 is engaged (details will be described later). The rotational speed (turbine rotational speed) of the turbine runner 22 constituting the torque converter 20 is detected by a turbine rotation sensor 87. The detected turbine rotational speed is output to a transmission control unit (hereinafter referred to as "TCU") 74 described later.

[0019] The forward / reverse switching mechanism 30 switches between forward rotation and reverse rotation of drive wheels (forward travel and reverse travel of a vehicle). The forward / reverse switching mechanism 30 mainly includes a double-pinion type planetary gear train 31, a forward clutch 32, and a reverse brake 33. The forward / reverse switching mechanism 30 is configured such that the transmission path for the engine driving force can be switched by controlling the respective states of the forward clutch 32 and the reverse brake 33.

[0020] More specifically, when the D range (forward travel range) is selected, by engaging the forward clutch 32 and releasing the reverse brake 33, the rotation of the turbine shaft 25 is transmitted as it is to a primary shaft 51 described later, enabling the vehicle to travel forward. Further, when the R range (reverse travel range) is selected, by releasing the forward clutch 32 and engaging the reverse brake 33, the planetary gear train 31 is actuated to reverse the rotational direction of the primary shaft 51, enabling the vehicle to travel in reverse.

[0021] When the N range or P range is selected, the turbine shaft 25 and the primary shaft 51 are disconnected (the transmission of engine driving force is interrupted) by releasing the forward clutch 32 and the reverse brake 33, and the forward / reverse switching mechanism 30 is placed in a neutral state in which no power is transmitted to the primary shaft 51. However, when generating power in the P range, the forward clutch 32 is engaged and the reverse brake 33 is released (details will be described later).

[0022] The operations (engagement and release) of the forward clutch 32 and the reverse brake 33 are controlled by a TCU 74, a valve body 75, and a manual valve 80 which will be described later.

[0023] The continuously variable transmission 50 includes a primary shaft 51 connected to the turbine shaft 25 of the torque converter 20 via the forward / reverse switching mechanism 30, and a secondary shaft 55 disposed parallel to the primary shaft 51.

[0024] A primary pulley 52 is provided on the primary shaft 51. The primary pulley 52 includes a fixed sheave 52a joined to the primary shaft 51, and a movable sheave 52b disposed opposite to the fixed sheave 52a and slidably mounted in the axial direction of the primary shaft 51, and is configured such that the interval between the cone surfaces of the respective sheaves 52a and 52b, that is, the pulley groove width, can be changed. On the other hand, a secondary pulley 53 is provided on the secondary shaft 55. The secondary pulley 53 includes a fixed sheave 53a joined to the secondary shaft 55, and a movable sheave 53b disposed opposite to the fixed sheave 53a and slidably mounted in the axial direction of the secondary shaft 55, and is configured such that the pulley groove width can be changed.

[0025] A chain 54 that transmits driving force is wrapped between the primary pulley 52 and the secondary pulley 53. By changing the groove width of the primary pulley 52 and the secondary pulley 53, the ratio of the chain 54's winding diameter to each pulley 52 and 53 (pulley ratio) is changed, and the gear ratio is changed steplessly. Here, if the winding diameter of the chain 54 with respect to the primary pulley 52 is Rp and the winding diameter with respect to the secondary pulley 53 is Rs, then the gear ratio i is expressed as i = Rs / Rp. Therefore, the gear ratio i can be obtained by dividing the primary pulley rotation speed Np by the secondary pulley rotation speed Ns (i = Np / Ns).

[0026] Here, a hydraulic chamber 52c is formed on the rear side of the movable sheave 52b of the primary pulley 52. ​​On the other hand, a hydraulic chamber 53c is formed on the rear side of the movable sheave 53b of the secondary pulley 53. The groove widths of the primary pulley 52 and the secondary pulley 53 are set and changed by adjusting the primary hydraulic pressure introduced into the hydraulic chamber 52c of the primary pulley 52 and the secondary hydraulic pressure introduced into the hydraulic chamber 53c of the secondary pulley 53.

[0027] A motor generator (electric motor) 40 is connected to the other end of the primary shaft 51 of the continuously variable transmission 50 in a manner that allows for torque transmission. The motor generator 40 is, for example, a three-phase AC type AC synchronous motor. In this embodiment, the motor generator 40 is of a type that uses permanent magnets for the rotor and coils for the stator. The motor generator 40 mainly operates as a driving force source to drive the vehicle and acts as a generator during regeneration, etc. In addition, the motor generator 40 may use coils for the rotor and permanent magnets for the stator. Furthermore, instead of an AC synchronous motor, the motor generator 40 may be, for example, an AC induction motor or a DC motor.

[0028] The continuously variable transmission 50 is equipped with a mechanical oil pump 35 to pump oil used in the continuously variable transmission 50, the forward / reverse switching mechanism 30, the output clutch 61, the transfer clutch 64, the motor generator 40, etc. The mechanical oil pump 35 draws in oil stored in the oil pan, pressurizes it, and pumps it to the continuously variable transmission 50, the forward / reverse switching mechanism 30, the output clutch 61, the transfer clutch 64, the motor generator 40, etc. For example, a trochoid pump or a vane pump can be used as the mechanical oil pump 35. The drive shaft of the mechanical oil pump 35 is connected to the turbine shaft 25 and the primary shaft 51, respectively, via a chain or the like, so as to be able to transmit torque. In other words, the mechanical oil pump 35 is configured to be driveable by the engine 10 and the motor generator 40, respectively.

[0029] Furthermore, the continuously variable transmission 50 is equipped with an electric oil pump 36 to ensure the necessary oil pressure when the rotation (discharge pressure) of the mechanical oil pump 35 decreases, for example, when the engine 10 is stopped during low-speed driving. The electric oil pump 36 is driven by an electric motor and pressurizes and discharges the oil stored in the oil pan. The operation of the electric oil pump 36 is controlled by the TCU 74.

[0030] As shown in Figures 2 and 3, the discharge port of the electric oil pump 36 is connected to the discharge port of the mechanical oil pump 35 via a check valve 37 that opens when the discharge pressure of the electric oil pump 36 is higher than the discharge pressure of the mechanical oil pump 35 (above a predetermined pressure). The check valve 37 is composed of, for example, a spring and a ball, or a spring and a rod-shaped valve body, and is a check valve that allows oil to flow from the electric oil pump 36 to the mechanical oil pump 35 and prohibits oil from flowing from the mechanical oil pump 35 to the electric oil pump 36.

[0031] Furthermore, an oil passage 39, which communicates with the output clutch 61, is connected to the discharge port of the electric oil pump 36 via a second check valve 38. The second check valve 38 opens when the oil pressure (discharge pressure) on the electric oil pump 36 side is higher (above a predetermined pressure) than the oil pressure on the output clutch 61 side. In other words, the second check valve 38 allows oil to flow (supply) from the electric oil pump 36 to the output clutch 61, while prohibiting oil to flow (backflow) from the output clutch 61 to the electric oil pump 36.

[0032] Returning to Figure 1, the secondary shaft 55 of the continuously variable transmission 50 is connected to the counter shaft 60 via a reduction gear (secondary reduction gear) 59 consisting of a pair of gears (reduction drive gear and reduction driven gear). The driving force converted by the continuously variable transmission 50 is transmitted to the counter shaft 60 via the reduction gear 59. An output clutch 61 and a parking gear 62, which constitutes the parking mechanism, are attached to the counter shaft 60. The parking mechanism locks the wheels to prevent them from rotating when the P range is selected. The parking mechanism locks the parking gear 62 by engaging the parking pawl with the parking gear 62, thereby putting the continuously variable transmission 50 into the parking state.

[0033] The output clutch 61 is installed between the secondary shaft 55 of the continuously variable transmission 50 and the drive wheels, and intermittently transmits torque between the continuously variable transmission 50 (engine 10 and motor generator 40) and the drive wheels. For example, when the vehicle is stopped and the engine 10 is used to rotate the motor generator 40 to generate electricity (P range generation), the output clutch 61 is released to disconnect the engine 10 and motor generator 40 from the wheels. Therefore, the output clutch 61 is engaged at all other times (for example, while driving). The control (engaging and disengaging) of the output clutch 61 is performed by the TCU 74, which will be described later.

[0034] The counter shaft 60 is connected to the front drive shaft 66 via a counter gear 63 consisting of a pair of gears (counter drive gear and counter driven gear). The driving force transmitted to the counter shaft 60 is transmitted to the front differential (hereinafter also referred to as "front differential") 67 via the counter gear 63 and the front drive shaft 66. The front differential 67 is, for example, a bevel gear type differential. The driving force from the front differential 67 is transmitted to the left front wheel via the left front drive shaft and to the right front wheel via the right front drive shaft.

[0035] On the other hand, a transfer clutch 64 is interposed downstream of the counter gear 63 (counter drive gear) on the counter shaft 60 mentioned above, which adjusts the driving force transmitted to the rear differential (hereinafter also referred to as "rear differential") 69. The transfer clutch 64 controls its clamping force (i.e., the torque distribution rate to the rear wheels) according to the driving state of the four wheels (for example, the slip state of the front wheels) and engine torque. Therefore, the driving force transmitted to the counter shaft 60 is distributed according to the clamping force of the transfer clutch 64 and transmitted to the rear wheels.

[0036] More specifically, the rear end of the countershaft 60 is connected to a propeller shaft 68 extending to the rear of the vehicle via a transfer gear 65 consisting of a pair of gears (transfer drive gear and transfer driven gear). Therefore, the driving force transmitted to the countershaft 60 and regulated (distributed) by the transfer clutch 64 is transmitted from the transfer gear 65 (transfer driven gear) to the rear differential 69 via the propeller shaft 68.

[0037] The rear differential 69 is connected to both the left and right rear drive shafts. The driving force from the rear differential 69 is transmitted to the left rear wheel via the left rear drive shaft and to the right rear wheel via the right rear drive shaft.

[0038] As described above, the hybrid vehicle 1 can drive the wheels (vehicle) with two power sources: the engine 10 and the motor generator 40. The motor generator 40 can also be used for regenerative braking and power generation. Furthermore, as described above, the power transmission system is configured such that, for example, when the shift lever 77 is operated to the D range, the forward clutch 32 is engaged, and the engine power (and the power of the motor generator 40) is input to the primary shaft 51 of the continuously variable transmission 50. The power converted by the continuously variable transmission 50 is output from the secondary shaft 55 and transmitted to the front drive shaft 66 via the reduction gear 59, counter shaft 60, and counter gear 63. The power is then distributed to the left and right by the front differential 67 and transmitted to the left and right front wheels.

[0039] Meanwhile, a portion of the driving force transmitted to the countershaft 60 is transmitted to the propeller shaft 68 via the transfer clutch 64 and the transfer gear 65. When a predetermined clutch torque is applied to the transfer clutch 64, the driving force distributed according to that clutch torque is output to the propeller shaft 68. This driving force is then transmitted to the rear wheels via the rear differential 69.

[0040] Furthermore, when the R range is selected, the forward clutch 32 is released and the reverse brake 33 is engaged, reversing the rotation direction of the primary shaft 51. The subsequent torque flow is the same as in the D range described above. When the P range is selected, both the forward clutch 32 and the reverse brake 33 are released, disconnecting the turbine shaft 25 and the primary shaft 51 (the transmission of engine power is interrupted). When generating power in the P range, the forward clutch 32 is engaged, the reverse brake 33 is released, and the output clutch 61 is released, allowing the engine 10 to drive the motor generator 40, while preventing power from being transmitted to the front and rear wheels (details will be described later).

[0041] The engine 10, motor generator 40, and continuously variable transmission 50, which are the driving force sources of the vehicle, are comprehensively controlled by a control system that includes a hybrid vehicle control unit (hereinafter referred to as "HEV-CU") 70, an ECU 71, a power control unit (hereinafter referred to as "PCU") 72, a TCU 74, a vehicle dynamics control unit (hereinafter referred to as "VDCU") 76, and the like.

[0042] HEV-CU70, ECU71, PCU72, TCU74, and VDCU76 each consist of a microprocessor that performs calculations, an EEPROM that stores programs for the microprocessor to execute various processes, RAM that stores various data such as calculation results, a backup RAM that holds the stored contents, and an input / output interface, etc.

[0043] HEV-CU70, ECU71, PCU72, TCU74, and VDCU76 are each connected to each other via CAN (Controller Area Network) 100, enabling them to communicate with one another.

[0044] The HEV-CU70 is connected to various sensors, including, for example, an accelerator pedal sensor 81 that detects the amount the accelerator pedal is pressed, i.e., the amount of accelerator pedal operation, and a resolver 82 that detects the rotational position (rotational speed) of the motor generator 40. The HEV-CU70 also receives various information via CAN100 from the ECU71, PCU72, TCU74, VDCU76, etc., such as engine speed, primary pulley rotation speed, secondary pulley rotation speed, brake operation amount, steering wheel steering angle, and yaw rate.

[0045] Based on the various information acquired, the HEV-CU70 comprehensively controls the drive of the engine 10, motor generator 40, and continuously variable transmission 50. For example, based on various information such as the accelerator pedal operation amount (driver's requested driving force), engine speed, motor speed, primary pulley speed, secondary pulley speed, vehicle driving state (vehicle speed, steering angle, etc.), and the charge level (SOC) of the high-voltage battery 73, the HEV-CU70 determines the requested output of the engine 10, the torque command value of the motor generator 40, and the target gear ratio of the continuously variable transmission 50. The HEV-CU70 then outputs the determined requested output, torque command value, target gear ratio, etc., via CAN100. Furthermore, in the P range state, if the SOC of the high-voltage battery 73 falls below a predetermined value, the HEV-CU70 controls the engine 10 to drive the motor generator 40 to generate electricity (P range generation) and charge the high-voltage battery 73 (details will be described later).

[0046] In the ECU71, the cylinder is identified from the output of the camshaft angle sensor mentioned above, and the engine speed (rotational velocity) is determined from the change in the rotational position of the crankshaft 15 detected by the output of the crankshaft angle sensor 84. In addition, the ECU71 acquires various information such as intake air volume, accelerator pedal operation amount, air-fuel ratio of the air-fuel mixture, and water temperature based on the detection signals input from the various sensors mentioned above. Based on this acquired information and the request output from the HEV-CU70, the ECU71 controls the engine 10 by controlling the fuel injection amount, ignition timing, and various devices such as the electronically controlled throttle valve. The ECU71 operates the engine 10 when generating power in P range.

[0047] Furthermore, the ECU71 calculates the engine torque (output torque) of the engine 10 based on, for example, the amount of intake air detected by the airflow meter 83 and the engine speed. The ECU71 then transmits information such as engine speed (rotational speed) and engine torque to the TCU74, HEV-CU70, etc., via the CAN100.

[0048] The PCU 72 drives the motor generator 40 via the inverter 72a based on the torque command value from the HEV-CU 70. Here, the inverter 72a converts the DC power from the high-voltage battery 73 into three-phase AC power and supplies it to the motor generator 40. On the other hand, during regeneration or when generating power in P range, the inverter 72a converts the AC voltage generated by the motor generator 40 into DC voltage to charge the high-voltage battery 73.

[0049] The VDCU76 is connected to a brake switch 89 that detects whether or not the brake pedal is pressed, and a brake fluid pressure sensor 90 that detects the master cylinder pressure (brake hydraulic pressure) of the brake actuator. The VDCU76 is also connected to a wheel speed sensor 91 that detects the rotational speed (vehicle speed) of each wheel of the vehicle.

[0050] The VDCU76 brakes the vehicle by driving the brake actuator according to the amount of brake pedal operation (pressure), and also detects vehicle behavior using various sensors (e.g., wheel speed sensor 91, steering angle sensor, acceleration sensor, yaw rate sensor, etc.). By controlling the brakes through automatic pressure application and torque control of the engine 10, etc., it suppresses skidding and ensures vehicle stability during cornering. Furthermore, the VDCU76 incorporates an anti-lock braking function (ABS function) that prevents wheel lock that occurs when braking suddenly or on slippery surfaces, maintains the appropriate slip ratio of each wheel to ensure directional stability and steering performance during braking and obtains optimal braking force, and a traction control function (TCS function) that suppresses wheelspin of the drive wheels caused by slippery surfaces or excessive driving force to ensure vehicle stability and acceleration during starting and acceleration.

[0051] The VDCU76 transmits braking information (brake operation information) such as the detected brake switch 89 and brake fluid pressure, as well as wheel speed (vehicle speed), etc., to the TCU74, HEV-CU70, and ECU71, etc., via CAN100.

[0052] The TCU74 is connected to a primary pulley rotation sensor 85 that detects the rotational speed of the primary pulley 52, and a secondary pulley rotation sensor 86 that detects the rotational speed of the secondary pulley 53 (corresponding to vehicle speed). The TCU74 is also connected to a turbine rotation sensor 87, an output clutch rotation sensor 88, and other sensors.

[0053] Furthermore, the TCU74 receives information such as engine torque from the ECU71 via CAN100, information such as motor torque and accelerator pedal operation from the HEV-CU70, and information such as vehicle speed and brake operation from the VDCU76.

[0054] The TCU74 continuously changes the gear ratio of the continuously variable transmission 50 based on the acquired information (vehicle driving status) and the target gear ratio from the HEV-CU70.

[0055] In this process, the TCU 74 controls the drive of the solenoid valves (electromagnetic valves) that constitute the valve body 75, thereby adjusting the hydraulic pressure supplied to the hydraulic chamber 52c of the primary pulley 52 and the hydraulic chamber 53c of the secondary pulley 53, and changing the gear ratio of the continuously variable transmission 50.

[0056] Furthermore, as shown in Figures 2 and 3, the TCU 74 controls the drive of the linear solenoid 751 and control valve 752 that constitute the valve body 75, thereby adjusting the amount of oil (hydraulic pressure) supplied to / discharged from the forward clutch 32 or the reverse brake 33 to engage / disengage the forward clutch 32 or the reverse brake 33. Whether to supply (or discharge) oil to the forward clutch 32 side or to the reverse brake 33 side is switched by a manual valve 80 that is configured to move in conjunction with the shift lever 77.

[0057] Here, for example, a shift lever (select lever) 77 is provided on the vehicle's floor (center console) or the like, which accepts the driver's operation to selectively switch the operating state (range) of the continuously variable transmission 50. A range switch 79 is attached to the shift lever 77 so as to move in conjunction with the shift lever 77 and detects the selected position of the shift lever 77. The range switch 79 is connected to the TCU 74, and the detected selected position of the shift lever 77 is read into the TCU 74. The shift lever 77 can selectively switch between drive "D" range, manual "M" range, parking "P" range, reverse "R" range, neutral "N" range, etc. Alternatively, a switch-type select mechanism may be used instead of the shift lever 77.

[0058] When the shift lever 77 is operated and the D range (forward driving range) is selected, the manual valve 80 moves, supplying oil to the hydraulic chamber of the forward clutch 32 and discharging oil from the hydraulic chamber of the reverse brake 33. As a result, the forward clutch 32 is engaged and the reverse brake 33 is released, allowing the vehicle to move forward. On the other hand, when the shift lever 77 is operated and the R range (reverse driving range) is selected, the manual valve 80 moves, supplying oil to the hydraulic chamber of the reverse brake 33 and discharging oil from the hydraulic chamber of the forward clutch 32. As a result, the reverse brake 33 is engaged and the forward clutch 32 is released, allowing the vehicle to move in reverse.

[0059] When the shift lever 77 is operated and the N or P range is selected, oil is discharged from the hydraulic chamber of the forward clutch 32 and the hydraulic chamber of the reverse brake 33. As a result, the forward clutch 32 and the reverse brake 33 are released (the transmission of engine power is interrupted), and the continuously variable transmission 50 enters a neutral state. However, when generating power in the P range, oil is supplied to the hydraulic chamber of the forward clutch 32, and it enters a engaged state. Here, the manual valve 80 is configured to supply oil (hydraulic pressure) to the forward clutch 32 when the P range is selected.

[0060] Furthermore, the TCU 74 controls the engagement and disengagement of the output clutch 61 by adjusting the amount of oil (oil pressure) supplied to and discharged from the output clutch 61 through the drive of the linear solenoid 754 and control valve 755 that constitute the valve body 75 described above. The TCU 74 engages the output clutch 61 in P range and disengages the output clutch 61 when generating power in P range (see Figure 4). Also, when generating power in P range, if the vehicle is switched to R range (shift operation is performed), the TCU 74 drives the electric oil pump 36 and supplies oil to the output clutch 61 through the oil passage 39. The TCU 74 stops driving the electric oil pump 36 when the oil chamber of the output clutch 61 is filled with oil and the oil pressure on the output clutch 61 side rises and the second check valve 38 closes.

[0061] Furthermore, the TCU 74 adjusts the hydraulic pressure supplied to the transfer clutch 64 (i.e., adjusts the clamping force) by controlling the drive of the solenoid valves that constitute the valve body 75 described above, thereby adjusting the distribution ratio of the driving force transmitted to the rear wheels.

[0062] As described above, and as shown in Figure 4, in the P range, the lock-up clutch 24 is released, the forward clutch 32 is released, the output clutch 61 is engaged, the transfer clutch 64 is engaged, and the reverse brake 33 is released. In the P range power generation state, the lock-up clutch 24 is engaged, the forward clutch 32 is engaged, the output clutch 61 is released, the transfer clutch 64 is engaged, and the reverse brake 33 is released. In the D range state, the lock-up clutch 24 is engaged according to the vehicle speed, the forward clutch 32 is engaged, the output clutch 61 is engaged, the transfer clutch 64 is engaged, and the reverse brake 33 is released. In the R range state, the lock-up clutch 24 is released, the forward clutch 32 is released, the output clutch 61 is engaged, the transfer clutch 64 is engaged, and the reverse brake 33 is engaged.

[0063] Therefore, when transitioning from the P range to the D range, only the forward clutch 32 (system 1) needs to be engaged. Also, when transitioning from the P range to the R range, only the reverse brake 33 (system 1) needs to be engaged. Furthermore, when transitioning from the P range generator state to the D range, only the output clutch 61 (system 1) needs to be engaged. On the other hand, when transitioning from the P range generator state to the R range, both the reverse brake 33 and the output clutch 61 (system 2) need to be engaged.

[0064] In particular, the HEV-CU70, TCU74, and ECU71 (hereinafter sometimes referred to as "HEV-CU70, etc.") work together to enable power generation using the motor generator 40 in P range (P range power generation), and have a function to prevent a delay in response to a shift operation even if the vehicle is switched to R range (shift operation is performed) during P range power generation. In the HEV-CU70, TCU74, and ECU71, this function is realized by the execution of programs stored in their respective EEPROMs, etc., by a microprocessor. The HEV-CU70, TCU74, and ECU71 function as the control unit described in the claims.

[0065] In the HEV-CU70 and similar models, when the state of charge (SOC) of the high-voltage battery 73 falls below a predetermined value while in P range, the output clutch 61 is released, the forward clutch 32 is engaged (see Figure 4), and the engine 10 is started to drive the motor generator 40 as a generator (generates electricity). At the same time (when generating electricity in P range), the HEV-CU70 and similar models also engage the lock-up clutch 24 and the transfer clutch 64 (see Figure 4).

[0066] Furthermore, in the HEV-CU70 and similar models, when generating power in P range, the EPB (electric parking brake) is automatically turned on and the parking mechanism (parking gear 62) is locked (see Figure 4).

[0067] In the HEV-CU70 and similar units, when the state of charge (SOC) of the high-voltage battery 73 reaches a predetermined value or higher (when charging is complete), the P-range power generation is terminated and the unit returns to the normal P-range state (forward clutch 32 released, lock-up clutch 24 released, output clutch 61 engaged) (see Figure 4).

[0068] In the HEV-CU70 and similar models (TCU74), when power generation is being performed in P range, if the vehicle is switched to R range (shift operation is performed), power generation in P range is terminated, and the electric oil pump 36 is driven to supply oil to the output clutch 61 through the oil passage 39. Therefore, the output clutch 61 is supplied with oil from both the mechanical oil pump 35 and the electric oil pump 36.

[0069] Furthermore, in the HEV-CU70 and similar models (TCU74), when oil is filled into the hydraulic chamber of the output clutch 61 and the hydraulic pressure on the output clutch 61 rises, causing the second check valve 38 to close, the operation of the electric oil pump 36 is stopped.

[0070] Incidentally, the amount of oil leaking (dropping) from the hydraulic chamber of the output clutch 61 correlates with the time from when power generation starts in P range until the system switches to R range. Therefore, the HEV-CU70, etc. (TCU74) measures the time from when power generation starts in P range until the system switches to R range, sets (controls) the driving time of the electric oil pump 36 according to the measured time, and drives the electric oil pump 36 until the set driving time has elapsed. In other words, the HEV-CU70, etc. (TCU74) estimates the amount of oil leaking (dropping) from the hydraulic chamber of the output clutch 61 and drives the electric oil pump 36 according to that amount.

[0071] Next, the operation of the hybrid vehicle 1 will be explained with reference to Figures 5 and 6. Figures 5 and 6 are flowcharts showing the processing procedure for power generation in the P range in the hybrid vehicle 1. This process is mainly performed repeatedly at predetermined timings in the HEV-CU70, ECU71, and TCU74.

[0072] In step S100, a determination is made as to whether or not the system has shifted to the P range. If it has shifted to the P range, the process proceeds to step S102. On the other hand, if it has not shifted to the P range, the process is temporarily exited.

[0073] In step S102, a determination is made as to whether the SOC of the high-voltage battery 73 is below a predetermined value (a%). If the SOC is higher than the predetermined value (a%), the forward clutch 32 is released (step S104) and the lock-up clutch 24 is released (step S106). In other words, the system returns to the normal P range state. The system then exits this process. On the other hand, if the SOC is below the predetermined value (a%), the process proceeds to step S108.

[0074] In step S108, the output clutch 61 is released. Subsequently, in step S110, a timer (t1) is activated to measure the time from when power generation starts in P range until the vehicle switches to R range.

[0075] Next, in step S112, the forward clutch 32 is engaged, and in step S114, the lock-up clutch 24 is engaged.

[0076] Next, in step S116, a determination is made as to whether or not the engine 10 is running. If the engine 10 is not running, then in step S118, the engine 10 is started, and then the process proceeds to step S120. On the other hand, if the engine 10 is already running, the process proceeds to step S120.

[0077] In step S120, power generation is performed in P range. Next, in step S122, a determination is made as to whether the SOC of the high-voltage battery 73 is above a predetermined value (b%) (whether charging is complete or not). If the SOC is higher than the predetermined value (b%), the forward clutch 32 is released (step S124), the lock-up clutch 24 is released (step S126), and the output clutch 61 is engaged (step S128). In other words, the system returns to the normal P range state. After that, the system exits this process. On the other hand, if the SOC is below the predetermined value (b%), the process proceeds to step S130.

[0078] In step S130, a determination is made as to whether or not the shift operation has been accepted. If the shift operation has not been accepted, the process proceeds to step S120, and power generation in P range continues. On the other hand, if the shift operation has been accepted, the process proceeds to step S132.

[0079] In step S132, a determination is made as to whether or not the range has shifted to the R range. If the range has shifted to a range other than R, the process proceeds to step S133. On the other hand, if the range has shifted to R, the process proceeds to step S134.

[0080] In step S133, a determination is made as to whether or not the gear has been shifted to the D range. If the gear has been shifted to a range other than D, the process proceeds to step S124 described above, and the gear temporarily returns to the normal P range state before returning to the selected shift state. On the other hand, if the gear has been shifted to the D range, the process proceeds to step S126 described above, and the lock-up clutch 24 is released (step S126) and the output clutch 61 is engaged (step S128). In other words, the gear returns to the D range state. After that, the process is temporarily exited.

[0081] In step S134, the timer (t1) that measures the time from when power generation starts in P range until it is switched to R range is stopped. Subsequently, the forward clutch 32 is released (step S136) and the lock-up clutch 24 is released (step S138).

[0082] In the following step S140, a determination is made as to whether the SOC of the high-voltage battery 73 is below a predetermined value (c%). If the SOC is below the predetermined value (c%), the process proceeds to step S150. On the other hand, if the SOC is higher than the predetermined value (c%), the process proceeds to step S142.

[0083] In step S142, a determination is made as to whether the value of timer (t1) is greater than or equal to a predetermined value. If the value of timer (t1) is less than the predetermined value, the process proceeds to step S150. On the other hand, if the value of timer (t1) is greater than or equal to the predetermined value, the process proceeds to step S144.

[0084] In step S144, the electric oil pump 36 is driven at a predetermined rotational speed (i.e., oil is supplied to the output clutch 61). Next, in step S146, a determination is made as to whether a predetermined time (set time) has elapsed since the start of driving the electric oil pump 36. If the predetermined time (set time) has not elapsed since the start of driving the electric oil pump 36, the process proceeds to step S144, and the electric oil pump 36 is driven thereafter. On the other hand, if the predetermined time (set time) has elapsed since the start of driving the electric oil pump 36, the process proceeds to step S148.

[0085] In step S148, the electric oil pump 36 is deactivated. Next, in step S150, the reverse brake 33 is engaged. Then, in step S152, the output clutch 61 is engaged, meaning the vehicle switches to reverse driving mode. After that, the process is temporarily exited.

[0086] As described in detail above, according to this embodiment, when the P range is selected, the system is configured to supply oil (hydraulic oil) to the forward clutch 32. When the state of charge (SOC) of the high-voltage battery 73 falls below a predetermined value in the P range, the output clutch 61 is released, the forward clutch 32 is engaged, and the engine 10 is started, driving the motor generator 40 as a generator (power generation occurs). When power generation is being performed in the P range, if the system is switched to the R range (shift operation is performed), the electric oil pump 36 is driven, and oil is supplied to the output clutch 61 through the oil passage 39. Therefore, the electric oil pump 36 can assist in supplying oil (engaging) to one of the two clutch systems (output clutch 61 and reverse brake 33) that require engagement (oil supply) to switch to the R range (output clutch 61 in this embodiment). As a result, power generation using the motor generator 40 in the P range (P range power generation) is made possible, and even if the system is switched to the R range (shift operation is performed) while P range power generation is being performed, it is possible to prevent a delay in response to the shift operation.

[0087] According to this embodiment, a second check valve 38 is provided interposed in the oil passage 39 and opens when the hydraulic pressure (discharge pressure) on the electric oil pump 36 side is higher (above a predetermined pressure) than the hydraulic pressure on the output clutch 61 side. In other words, it is possible to allow the inflow of oil (oil supply) from the electric oil pump 36 to the output clutch 61, while prohibiting the inflow of oil (backflow) from the output clutch 61 to the electric oil pump 36. Therefore, after the output clutch 61 has been fully engaged, the second check valve 38 closes, preventing excessive oil supply from the electric oil pump 36.

[0088] Incidentally, the amount of oil leaking (dropping) from the hydraulic chamber of the output clutch 61 correlates with the time from when power generation starts in P range until the system switches to R range. According to this embodiment, the time from when power generation starts in P range until the system switches to R range is measured, and the driving time of the electric oil pump 36 is set according to the measured time. The electric oil pump 36 is then driven until the set driving time has elapsed. Therefore, the amount of oil leaking (dropping) from the hydraulic chamber of the output clutch 61 can be estimated, and the electric oil pump 36 can be driven according to that amount. Thus, it is possible to prevent unnecessary driving (operation beyond what is necessary) of the electric oil pump 36 and suppress power consumption.

[0089] According to this embodiment, the lock-up clutch 24 is engaged when generating power in P range. Therefore, the engine 10 and the motor generator 40 can be directly connected, making it possible to generate power more efficiently.

[0090] Although embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and various modifications are possible. For example, in the above embodiment, the electric oil pump 36 and the output clutch 61 are connected by an oil passage 39, but instead of the output clutch 61, the electric oil pump 36 and the reverse brake 33 (downstream of the control valve 752) may be connected by an oil passage.

[0091] In the above embodiment, the time from when power generation starts in P range until it is switched to R range is measured, and the driving time of the electric oil pump 36 is set according to the measured time, and the electric oil pump 36 is driven until the set driving time has elapsed. In addition, if the measured time exceeds a predetermined time during measurement, the electric oil pump 36 may be temporarily driven (to the extent that the clutch is not engaged) and the measured time may be reset (restarted).

[0092] Furthermore, when generating power in P range, the reverse brake 33 may be engaged instead of the forward clutch 32. More specifically, the manual valve 80 may be configured to supply oil (hydraulic pressure) to the reverse brake 33 instead of the forward clutch 32 when the P range is selected, and instead of the oil passage connecting the electric oil pump 36 to the output clutch 61 or the reverse brake 33, the electric oil pump 36 may be connected to the output clutch 61 or the forward clutch 32, and when the HEV-CU70 or the like is generating power in P range and is switched to D range (shifted), the electric oil pump 36 may be driven and oil may be supplied to the output clutch 61 or the forward clutch 32 through the oil passage.

[0093] In the above embodiment, the HEV-CU70, ECU71, TCU74, VDCU76, etc., are connected to each other via CAN100 to enable communication (system configuration). However, the system configuration is not limited to the configuration of the above embodiment. For example, the ECU71 that controls the engine 10 and the TCU74 that controls the continuously variable transmission 50 may be configured as a single piece of hardware. [Explanation of symbols]

[0094] 1. Hybrid vehicle 10 Engines 15 Crank Axle 20 Torque Converter 21 Pump Impeller 22 Turbine Runner 23 Status 24 Lock-up clutch 25 Turbine shaft 30 Forward / Forward Switching Mechanism 31 Planetary gear train 32 Forward clutch 33 Reverse brake 35 Mechanical oil pump 36 Electric oil pump 37 Check valve 38. Second check valve 39 Oil passage (hydraulic circuit) 40 Motor Generator 50 Continuously Variable Transmission 51 Primary axis 52 Primary Pulley 53 Secondary Pulley 54 chain 55 Secondary axis 59. Reduction gear (secondary reduction gear) 60 counter axis 61 Output clutch 62 Parking gear 63 Counter gear 64 Transfer Clutch 65 Transfer Gear 66 Front drive shaft 67 Front Differential 68 Propeller Shaft 69 Rear Differential 70 HEV-CU 71 ECU 72 PCU 73 High-voltage battery 74 TCU 75 Valve Body 751, 754 Linear Solenoid 752, 755 Control Valves 76 VDCU 77 Shift lever 79 Range switch 80 Manual Valve 81 Accelerator pedal sensor 82 resolvers 83 Airflow Meter 84 Crank angle sensor 85 Primary pulley rotation sensor 86 Secondary pulley rotation sensor 87 Turbine rotation sensor 88 Output clutch rotation sensor 89 Brake switch 90 Brake fluid pressure sensor 91 Wheel speed sensor 100 CAN

Claims

1. In a hybrid vehicle in which the engine is connected to one end of the primary shaft of a continuously variable transmission (CVT) via a forward / reverse switching mechanism including a forward clutch and a reverse brake, the other end of the primary shaft of the CVT is connected to a motor generator, and the secondary shaft of the CVT is connected to the drive wheels via an output clutch, A mechanical oil pump driven by the aforementioned engine and motor generator, which pressurizes and discharges oil, An electric oil pump, driven by an electric motor, discharges oil through a check valve that opens when the discharge pressure is higher than the discharge pressure of the mechanical oil pump, A manual valve that switches the supply of oil to the forward clutch and the reverse brake according to the shift operation state, An oil passage connecting the electric oil pump and the output clutch or the reverse brake, The system includes a control unit that controls the driving of the engine, the motor generator, and the electric oil pump, and the engagement and disengagement of the forward clutch, the reverse brake, and the output clutch, The manual valve is configured to supply oil to the forward clutch when the parking range is selected. The aforementioned control unit is When the charge level of the high-voltage battery falls below a predetermined value in the parking range, the output clutch is released, the forward clutch is engaged, and the engine is started to drive the motor generator as a generator. When generating power in the parking range, if the reverse driving range is selected, the electric oil pump is driven and oil is supplied to the output clutch or the reverse brake through the oil passage. A hybrid vehicle characterized by the following features.

2. The hybrid vehicle according to claim 1, further comprising a second check valve interposed in the oil passage, which opens when the hydraulic pressure on the electric oil pump side is higher than the hydraulic pressure on the output clutch or the reverse brake side.

3. The hybrid vehicle according to claim 2, characterized in that the control unit measures the time from when power generation starts in the parking range until the vehicle switches to the reverse range, sets the driving time of the electric oil pump according to the measured time, and drives the electric oil pump until the set driving time has elapsed.

4. Displaced between the engine and the forward / reverse switching mechanism, the torque converter includes a lock-up clutch, The output clutch is further equipped with a transfer clutch disposed between it and the driven wheel on the downstream side of the output clutch, The hybrid vehicle according to claim 3, characterized in that the control unit engages the lock-up clutch and the transfer clutch when generating power in the parking range.

5. The manual valve is configured to supply oil to the reverse brake instead of the forward clutch when the parking range is selected. Instead of connecting the electric oil pump with the output clutch or the reverse brake, the oil passage connects the electric oil pump with the output clutch or the forward clutch. The hybrid vehicle according to any one of claims 1 to 4, characterized in that the control unit drives the electric oil pump and supplies oil to the output clutch or the forward clutch through the oil passage when the forward driving range is selected while generating power in the parking range.

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