Hybrid vehicles

Abstract

A torque control device for a hybrid vehicle according to the present invention comprises: a maximum driving force calculation unit that calculates a parallel maximum driving force, which can be output during parallel driving in which a drive gear meshes with a driven gear, and a series maximum driving force, which can be output during series driving in which the drive gear is disengaged from the driven gear; and a power generation torque setting unit that sets an increase gradient of the power generation torque of a generator on the basis of an actual driving force during the parallel driving, the parallel maximum driving force, and the series maximum driving force.

Description

Technical Field

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[0001] The present disclosure relates to a hybrid vehicle.

Background Art

[0002] There is known a hybrid vehicle capable of parallel running in which drive wheels are driven by a drive motor supplied with electricity from an engine and a drive battery, and series running in which the drive motor drives the drive wheels by electricity generated by a generator and electricity supplied from the drive battery. Also known is a hybrid vehicle provided with two transmission stages, a high gear stage and a low gear stage, between the engine and the drive wheels, and selectively using the high gear stage and the low gear stage according to the running state and required output in parallel running (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the vehicle speed is limited by the engine speed (rotational speed) and the gear ratio (transmission ratio) of the gear stage, and parallel running cannot be performed beyond the upper limit vehicle speed in the low gear stage. Therefore, when the upper limit vehicle speed is exceeded in the low gear stage, it is required to transition from parallel running to series running.

[0005] On the other hand, in an engine clutch that blocks power transmission from the engine to the drive wheels by disengaging a drive gear on the engine side meshed with a driven gear on the drive wheel side on a clutch shaft provided between the drive wheels and the engine, when transitioning from parallel running to series running, it is required to cancel the driving torque of the engine with the power generation torque of the generator and bring the torque on the clutch shaft close to 0 Nm.

[0006] Therefore, when transitioning from parallel to series driving, if the engine's driving torque is abruptly offset by the generator's generating torque, the driving force will also decrease abruptly, worsening the vehicle's usability.

[0007] In view of the above circumstances, at least one embodiment of the present invention aims to provide a hybrid vehicle that can transition from parallel driving to series driving while avoiding a sudden decrease in driving force. [Means for solving the problem]

[0008] (1) A hybrid vehicle according to at least one embodiment of the present invention is a hybrid vehicle that drives the drive wheels by at least one of a drive motor or an engine, comprising: a drive battery that supplies electricity to the drive motor; a generator that is driven by the engine and supplies electricity to at least one of the drive motor or the drive battery; an engine clutch that disconnects the transmission of power from the engine to the drive wheel by disengaging the drive gear on the engine side that is meshed with the driven gear on the drive wheel side, on a clutch shaft provided between the drive wheel and the engine; and a drive clutch that disconnects the drive gear from the driven gear. The system includes a torque control device that controls the generated torque of the generator on the clutch shaft so that when the clutch is released, the generated torque of the generator cancels out the driving torque of the engine, the torque control device including a maximum driving force calculation unit that calculates the maximum parallel driving force that can be output during parallel driving when the drive gear is meshed with the driven gear, and the maximum series driving force that can be output during series driving when the drive gear is disengaged from the driven gear, and a generated torque setting unit that sets the increasing gradient of the generated torque based on the actual driving force during parallel driving, the maximum parallel driving force, and the maximum series driving force.

[0009] According to the configuration described in (1) above, when transitioning from parallel driving to series driving, the increase gradient of the generated torque is set based on the actual driving force during parallel driving, the maximum parallel driving force, and the maximum series driving force. As a result, the generated torque gradually increases in accordance with the increase gradient of the generated torque. This gradually cancels out the engine's driving torque with the generated torque of the generator, and the amount of electricity supplied from the generator to the drive motor gradually increases, thus avoiding a sudden drop in driving force. When the engine's driving torque is canceled out by the generated torque of the generator, the torque on the clutch shaft becomes 0 Nm, and the disengagement of the engine's drive gear, which is engaged with the driven gear on the drive wheel side, begins. When the drive gear is disengaged from the driven gear, power transmission from the engine to the drive wheels is interrupted, and the system transitions from parallel driving to series driving.

[0010] (2) In some embodiments, in the configuration of (1) above, the power generation torque setting unit reduces the increase gradient of the power generation torque to a predetermined reference value when the maximum parallel driving force is greater than the maximum series driving force and the actual driving force during parallel driving is greater than the maximum series driving force.

[0011] According to the configuration described in (2) above, when transitioning from parallel driving to series driving, if the maximum parallel driving force is greater than the maximum series driving force, and the actual driving force during parallel driving is greater than the maximum series driving force, the increase gradient of the generated torque becomes smaller than the reference value, and the generated torque gradually increases according to the increase gradient smaller than the reference value. Therefore, the engine's driving torque is gradually canceled out by the generator's generated torque, and the electricity supplied from the generator to the drive motor gradually increases. As a result, the driving force gradually decreases from the actual driving force during parallel driving and eventually reaches the maximum series driving force, thus avoiding a sudden drop in driving force. When the engine's driving torque is canceled out by the generator's generated torque, the torque on the clutch shaft becomes 0 Nm, and the engine's drive gear, which is meshed with the driven gear on the drive wheel side, begins to disengage. When the drive gear is disengaged from the driven gear, power transmission from the engine to the drive wheels is interrupted, and the system transitions from parallel driving to series driving.

[0012] (3) In some embodiments, in the configuration of (2) above, the power generation torque setting unit sets the increase gradient of the power generation torque to the reference value when the maximum parallel driving force is greater than the maximum series driving force and the actual driving force during parallel driving is less than or equal to the maximum series driving force.

[0013] According to the configuration described in (3) above, when transitioning from parallel to series driving, if the maximum parallel driving force is greater than the maximum series driving force, and the actual driving force during parallel driving is less than or equal to the maximum series driving force, the increase gradient of the generated torque becomes the reference value, and the generated torque gradually increases according to the increase gradient that becomes the reference value. Therefore, the engine's driving torque is gradually canceled out by the generator's generated torque, and the electricity supplied from the generator to the drive motor gradually increases. As a result, the transition from PR driving to SR driving is made while maintaining the actual driving force during PR driving, thus avoiding a sudden drop in driving force. When the engine's driving torque is canceled out by the generator's generated torque, the torque on the clutch shaft becomes 0 Nm, and the engine's drive gear, which is meshed with the driven gear on the drive wheel side, begins to disengage. When the drive gear is disengaged from the driven gear, the power transmission from the engine to the drive wheels is cut off, and the system transitions from PR driving to SR driving.

[0014] (4) In some embodiments, in the configuration of (2) or (3) above, the torque control device includes a required driving force calculation unit that calculates the required driving force required for the hybrid vehicle, and the power generation torque setting unit increases the gradient of the power generation torque greater than the reference value when the parallel maximum driving force is less than or equal to the series maximum driving force and the required driving force is greater than the parallel maximum driving force.

[0015] According to the configuration described in (4) above, when transitioning from parallel driving to series driving, if the maximum parallel driving force is less than or equal to the maximum series driving force, and the required driving force is greater than the maximum parallel driving force, the increase gradient of the generated torque becomes greater than the reference value. As a result, the generated torque gradually increases in accordance with the increase gradient greater than the reference value. Therefore, the engine's driving torque is offset faster than when the increase gradient of the generated torque is at the reference value, and the torque on the clutch shaft becomes 0 Nm. This allows for a faster transition from PR driving to SR driving than when the increase gradient of the generated torque is at the reference value.

[0016] (5) In some embodiments, in the configuration of (4) above, the power generation torque setting unit sets the increasing gradient of the power generation torque to the reference value when the parallel maximum driving force is less than or equal to the series maximum driving force and the requested driving force is less than or equal to the parallel maximum driving force.

[0017] According to the configuration described in (5) above, when transitioning from parallel driving to series driving, if the maximum parallel driving force is less than or equal to the maximum series driving force, and the required driving force for the hybrid vehicle is less than or equal to the maximum parallel driving force, the increase gradient of the generated torque becomes a reference value, and the generated torque gradually increases according to the reference increase gradient. Therefore, the engine's driving torque is gradually offset by the generated torque of the generator, and the electricity supplied from the generator to the drive motor gradually increases. As a result, it is possible to transition from parallel driving to series driving while gradually increasing the driving force from the actual driving force during PR driving towards the required driving force.

[0018] (6) In some embodiments, in the configuration of (1) or (2) above, the power generation torque setting unit increases the gradient of the power generation torque as the difference between the actual driving force and the series maximum driving force decreases, when the parallel maximum driving force is greater than the series maximum driving force and the actual driving force during parallel driving is greater than the series maximum driving force.

[0019] According to the configuration described in (6) above, when transitioning from parallel driving to series driving, if the maximum parallel driving force is greater than the maximum series driving force, and the actual driving force during parallel driving is greater than the maximum series driving force, the smaller the difference between the actual driving force and the maximum series driving force, the greater the gradient of increase in generated torque. As a result, the generated torque gradually increases in accordance with the gradient of increase in generated torque, which increases as the difference between the actual driving force and the maximum series driving force decreases, until the torque on the clutch shaft becomes 0 Nm. This allows for a transition from parallel driving to series driving while suppressing the decrease in actual driving force. [Effects of the Invention]

[0020] According to at least one embodiment of the present invention, it is possible to transition from parallel driving to series driving while avoiding a sudden decrease in driving force. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] [Figure 1] It is a figure which shows roughly the hybrid vehicle which concerns on Embodiment 1. [Figure 2] It is a figure which shows roughly the principal part structure of the hybrid vehicle shown in FIG. 1. [Figure 3] It is a block diagram which shows roughly the control structure of the hybrid vehicle shown in FIG. 2. [Figure 4] It is a block diagram which shows roughly the control structure of the HEV-ECU shown in FIG. 3. [Figure 5] It is a figure which shows the sudden decrease in the actual driving force that occurs at the PRLo upper limit vehicle speed when the parallel maximum driving force is greater than the series maximum driving force, and the actual driving force during parallel driving is greater than the series maximum driving force, and the increase gradient of the generated torque is set as a predetermined reference value. [Figure 6] It is a figure which shows the decrease in the actual driving force when the parallel maximum driving force is greater than the series maximum driving force, and the actual driving force during parallel driving is greater than the series maximum driving force, and the increase gradient of the generated torque is made smaller than the reference value. [Figure 7] It is a figure which shows the decrease in the actual driving force when the parallel maximum driving force is greater than the series maximum driving force, and the actual driving force during parallel driving is less than or equal to the series maximum driving force, and the increase gradient of the generated torque is set as the reference value. [Figure 8] It is a flowchart which shows roughly the control content of the torque control device shown in FIG. 4. [Figure 9] It is a time chart which shows the operation of the hybrid vehicle when the increase gradient of the generated torque of the generator is set as the reference value when transitioning from PR driving to SR driving. [Figure 10]This is a time chart showing the operation of a hybrid vehicle when the increase gradient of the generator's power generation torque is smaller than the standard value during the transition from PR (Pulse Reaction) driving to SR (Slow Reaction) driving. [Figure 11] This is a block diagram schematically showing the control configuration of the HEV-ECU according to Embodiment 2. [Figure 12] This figure shows the increase in actual driving force when the increase gradient of the generated torque is greater than the reference value, in a case where the maximum parallel driving force is less than or equal to the maximum series driving force, and the required driving force is less than or equal to the maximum parallel driving force. [Figure 13] Figure 11 is a flowchart that schematically shows the control process of the torque control device. [Figure 14] This is a time chart showing the operation of a hybrid vehicle when the increase in the generator's power generation torque is greater than the standard value during the transition from PR (Pressure Reaction) driving to SR (Slow Reaction) driving. [Figure 15] This figure shows the actual driving force during PR driving decreasing due to the set increasing gradient of generated torque when the maximum parallel driving force is greater than the maximum series driving force, and the actual driving force during PR driving is greater than the maximum series driving force. [Modes for carrying out the invention]

[0022] Hereinafter, several embodiments of the present invention will be described with reference to the attached drawings. However, the dimensions, materials, shapes, relative arrangements, etc., of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples. For example, expressions describing relative or absolute arrangements such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" should not only strictly represent such arrangements, but also represent states of relative displacement with tolerances, or angles or distances that allow the same function to be obtained. Furthermore, expressions describing shapes such as square or cylindrical should not only represent geometrically precise square or cylindrical shapes, but also shapes including concave and concave parts, chamfered parts, etc., to the extent that the same effect can be obtained. On the other hand, expressions such as "equipped," "possess," "features," "includes," or "has" a single component are not exclusive expressions that exclude the existence of other components.

[0023] [Embodiment 1] [Hybrid vehicles] Figure 1 is a schematic diagram showing a hybrid vehicle 1 according to Embodiment 1. As shown in Figure 1, the hybrid vehicle 1 according to Embodiment 1 is a hybrid vehicle (HV, HEV) that drives the drive wheels 14 by at least one of a drive motor 10 or an engine 12. The hybrid vehicle 1 according to Embodiment 1 is a plug-in hybrid vehicle (PHV, PHEV) that can be charged from an external device (e.g., a fast charger) while stationary (hereinafter referred to as "external charging") and can supply power to an external source (e.g., a general household) while stationary (hereinafter referred to as "external power supply"), but is not limited to this. Furthermore, the hybrid vehicle 1 according to Embodiment 1 is a hybrid vehicle that drives the two front wheels, but it may also be a hybrid vehicle that drives four wheels.

[0024] [Hybrid Vehicle Configuration] Figure 2 is a schematic diagram showing the main components of the hybrid vehicle 1 shown in Figure 1. As shown in Figure 2, the hybrid vehicle 1 according to Embodiment 1 includes, in addition to the drive motor 10 and engine 12 described above, a drive battery 16 (see Figure 1) that supplies electricity to the drive motor 10, a generator 18 driven by the engine 12 that supplies electricity to at least one of the drive motor 10 or the drive battery 16, an engine clutch 28 that disconnects the engine-side drive gear 26, which is meshed with the driven gear 22 (24) on the drive wheel side, on a clutch shaft 20 provided between the drive wheel 14 and the engine 12, thereby interrupting the transmission of power from the engine 12 to the drive wheel 14, and a torque control device 30 (see Figure 3) that controls the generated torque of the generator 18 on the clutch shaft 20 so that the generated torque of the generator 18 cancels out the driving torque of the engine 12 when the driven gear 26 is disconnected from the driven gear 22 (24).

[0025] As described above, the engine clutch 28 is a gear clutch in which the engine-side drive gear 26 meshes with the drive wheel-side driven gear 22(24) on the clutch shaft 20. When the drive gear 26 meshes with the driven gear 22(24), power is transmitted from the engine 12 to the drive wheels 14. When the drive gear 26 is disengaged from the driven gear 22(24), the transmission of power from the engine 12 to the drive wheels 14 is interrupted. As a result, the hybrid vehicle 1 according to Embodiment 1 is capable of engine-driven driving, where the engine 12 drives the drive wheels 14, or parallel driving (hereinafter referred to as "PR driving"), where the drive wheels 14 are driven by a drive motor 10 powered by electricity supplied from the engine 12 and the drive battery 16, while the drive gear 26 is meshed with the driven gear 22(24). Furthermore, by disconnecting the drive gear 26 from the driven gear 22 (24), it becomes possible to perform EV driving, in which the drive motor drives the drive wheels 14 using only electricity supplied from the drive battery 16, or series driving (hereinafter referred to as "SR driving"), in which the drive motor 10 drives the drive wheels 14 using electricity generated by the generator 18 and electricity supplied from the drive battery 16.

[0026] For example, the clutch shaft 20 of the engine clutch 28 is mounted coaxially with the output shaft (crankshaft) of the engine 12, a driven gear 22 (24) is rotatably arranged on the clutch shaft, and a drive gear 26 is slidably arranged in the axial direction of the clutch shaft 20. For example, the driven gear 22 (24) is composed of a dog gear with teeth on the outer surface of a hub, and the drive gear 26 is composed of a spline gear with teeth formed on the inner surface of a sleeve slidably mounted on the clutch shaft 20, but is not limited to this.

[0027] The hybrid vehicle 1 according to Embodiment 1 is provided with a transaxle 32 that incorporates the engine clutch 28 described above. The transaxle 32 is a power transmission device that integrates the transmission 36 and the final drive 38. In addition to the drive motor 10, engine 12, and generator 18 described above, the transaxle 32 is connected to a drive shaft (axle) 34 that drives the drive wheels 14 (front wheels) described above.

[0028] The transmission 36 is provided with a power transmission path 40 (hereinafter referred to as "motor power transmission path 40") that transmits power from the drive motor 10 to the final drive 38, and a power transmission path 42 (hereinafter referred to as "engine power transmission path 42") that transmits power from the engine 12 to the final drive 38. The final drive 38 is provided with a final gear 44 to which power is transmitted from the transmission 36, and a differential gear 46 to which the drive shaft 34 is connected.

[0029] The motor power transmission path 40 is provided with a motor clutch 48 that interrupts power transmission from the drive motor 10 to the drive wheels 14, but the motor clutch 48 is not essential. The motor clutch 48 is a wet multi-plate clutch that interrupts power transmission from the drive motor 10 to the final gear 44 by disengaging the drive disc 54 on the drive motor side, which is pressed against the driven disc 52 on the final gear side, at a clutch shaft 50 provided between the final gear 44 and the drive motor 10, but it is not limited to this, and for example, a dog clutch may also be used.

[0030] For example, the clutch shaft 50 is provided parallel to the drive shaft 34 and the output shaft of the drive motor 10, and a driven disc 52 and a drive disc 54 are arranged on the clutch shaft. The driven disc 52 is fixed to the clutch shaft 50, and the drive disc 54 is rotatably mounted on the clutch shaft 50. A drive gear 56 is provided on the drive disc 54, and the power of the drive motor 10 is transmitted to the drive disc 54 when the drive gear 56 meshes with a motor gear 58 provided on the output shaft of the drive motor 10. A driven gear 60 is provided on the clutch shaft 50, and the rotation of the clutch shaft 50 (driven disc 52) is transmitted to the final gear 44 when the driven gear 60 meshes with the final gear 44.

[0031] The motor clutch 48 is operated, for example, by a first actuator (ACT1) 62, and the first actuator 62 disconnects the drive disc 54, which is pressed against the driven disc 52, from the driven disc, thereby interrupting the power transmission from the drive motor 10 to the final gear 44.

[0032] In addition to the engine clutch 28 described above, the engine power transmission path 42 is provided with two gear stages, a low gear stage 64 and a high gear stage 66, which can be used depending on the driving conditions and required output during PR driving. For example, the low gear stage 64 is composed of a combination of a small-diameter gear 68 and a large-diameter gear 70, and the high gear stage 66 is composed of a combination of a large-diameter gear 72 and a small-diameter gear 74.

[0033] As described above, the clutch shaft 20 of the engine clutch 28 is provided coaxially with the output shaft (crankshaft) of the engine 12, and for example, a small-diameter gear 68 for the low gear stage 64 and a large-diameter gear 72 for the high gear stage 66 are rotatably arranged on the clutch shaft. The driven gears 22 and 24 described above are provided on the small-diameter gear 68 for the low gear stage 64 and the large-diameter gear 72 for the high gear stage 66, respectively, and when the drive gear 26 described above meshes with either one of them, either the low gear stage 64 or the high gear stage 66 is selected. In addition, a counter shaft 76 is provided parallel to the drive shaft 34 and the clutch shaft 20 of the engine clutch 28, and the large-diameter gear 70 for the low gear stage 64 and the small-diameter gear 74 for the high gear stage 66 are fixed on the counter shaft. The large-diameter gear 70 of the low gear stage 64 meshes with the small-diameter gear 68 of the low gear stage 64. When the drive gear 26 meshes with the driven gear 24 provided on the small-diameter gear 68 of the low gear stage 64, power is transmitted from the clutch shaft 20 through the low gear stage 64 to the counter shaft 76. The small-diameter gear 74 of the high gear stage 66 meshes with the large-diameter gear 72 of the high gear stage 66. When the drive gear 26 meshes with the driven gear 22 provided on the large-diameter gear 72 of the high gear stage 66, power is transmitted from the clutch shaft 20 through the high gear stage 66 to the counter shaft 76. The counter shaft 76 is provided with a counter gear 78, and when the counter gear 78 meshes with the final gear 44, the rotation of the counter shaft 76 is transmitted to the final gear 44.

[0034] The engine clutch 28 is operated, for example, by a second actuator (ACT2) 80, which disconnects the drive gear 26, which is meshed with the driven gear 22(24), from the driven gear 22(24), thereby interrupting the transmission of power from the engine 12 to the final gear 44.

[0035] Furthermore, the transaxle 32 is provided with a power transmission path 82 (hereinafter referred to as the "generator power transmission path 82") that transmits power from the engine 12 to the generator 18. The generator power transmission path 82 is provided with a drive gear 84 and a generator gear 86, with the drive gear 26 being provided on the clutch shaft 20 and the generator gear 86 being provided on the input shaft of the generator 18. As a result, the power from the engine 12 is input to the generator 18 through the clutch shaft 20, the drive gear 84 and the generator gear 86.

[0036] [Control configuration for hybrid vehicles] Figure 3 is a block diagram schematically showing the control configuration of the hybrid vehicle 1 shown in Figure 2. As shown in Figure 3, a motor control unit 88 (hereinafter referred to as "motor ECU 88") is electrically connected to the drive motor 10 described above, and the drive motor 10 is electrically controlled by the motor ECU 88.

[0037] A fuel tank 90 (see Figure 1) is connected to the engine 12 described above, and fuel is supplied to the engine 12 from the fuel tank 90. ​​In addition, an engine control unit 92 (hereinafter referred to as "engine ECU 92") is electrically connected to the engine 12, and the engine 12 is electrically controlled by the engine ECU 92.

[0038] A battery control unit 94 (hereinafter referred to as "battery ECU 94") is electrically connected to the aforementioned drive battery 16, and acquires battery status (e.g., state of charge (SOC), battery temperature) from a current sensor 96, a voltage sensor 98, and a temperature sensor 100 provided on the drive battery 16.

[0039] A generator control unit 102 (hereinafter referred to as "generator ECU 102") is electrically connected to the generator 18 described above, and the generator torque of the generator 18 is controlled by the generator ECU 102.

[0040] A clutch control unit 104 (hereinafter referred to as "clutch ECU 104") is electrically connected to the first actuator 62 that operates the motor clutch 48 and the second actuator 80 that operates the engine clutch 28, and the first actuator 62 and the second actuator 80 are electrically controlled by the clutch ECU 104.

[0041] The motor ECU88, engine ECU92, battery ECU94, generator ECU102, and clutch ECU104 each consist of a processor comprising an arithmetic unit, registers for storing instructions and information, and peripheral circuits, memory such as ROM (Read Only Memory) and RAM (Random Access Memory), and an input interface.

[0042] The motor ECU 88, engine ECU 92, battery ECU 94, generator ECU 102, and clutch ECU 104 are electrically connected to the vehicle control device 106 (hereinafter referred to as "HEV-ECU 106") via an in-vehicle network (CAN (Controller Area Network)). As a result, the motor ECU 88, engine ECU 92, battery ECU 94, generator ECU 102, and clutch ECU 104 are managed by the HEV-ECU 106, and in response to commands from the HEV-ECU 106, the motor ECU 88, engine ECU 92, battery ECU 94, generator ECU 102, and clutch ECU 104 control the drive motor 10, engine 12, drive battery 16, generator 18, first actuator 62, and second actuator 80. For example, the generator ECU 102 controls the generator 18 so that it generates electricity with the generated torque input to the generator ECU 102 from the HEV-ECU 106.

[0043] Furthermore, the HEV-ECU106 is connected to the vehicle control unit 108 (hereinafter referred to as "vehicle ECU108") via CAN. The vehicle ECU108 consists of a processor comprising an arithmetic unit, registers for storing instructions and information, and peripheral circuits, as well as memory such as ROM (Read Only Memory) and RAM (Random Access Memory), and an input interface.

[0044] For example, the vehicle ECU 108 is electrically connected to a speed sensor 110 and a wheel speed sensor 112. The vehicle ECU 108 receives information from the speed sensor 110 (vehicle speed) and the wheel speed sensor 112 (wheel speed), and the vehicle speed and wheel speed are then input from the vehicle ECU 108 to the HEV-ECU 106.

[0045] Furthermore, an accelerator position sensor 113 (hereinafter referred to as "APS113") is connected to the HEV-ECU106, and the accelerator opening angle is input from the APS113 to the HEV-ECU106.

[0046] [HEV-ECU Configuration] Figure 4 is a schematic block diagram showing the control configuration of the HEV-ECU 106 of the hybrid vehicle 1 shown in Figure 3. As shown in Figure 4, the HEV-ECU 106 has a torque control unit 114 that controls the generated torque of the generator 18 at the clutch shaft 20 so that the generated torque of the generator 18 cancels out the driving torque of the engine 12 when the driven gear 24 is disengaged, and constitutes a torque control device 30.

[0047] [Torque control device] The torque control device 30 (torque control unit 114) includes a maximum driving force calculation unit 116 that calculates the maximum parallel driving force that can be output during PR driving when the drive gear 26 is meshed with the driven gear 24, and the maximum series driving force that can be output during SR driving when the drive gear 26 is disengaged from the driven gear 24, and a power generation torque setting unit 118 that sets the increasing gradient of the power generation torque based on the actual driving force during PR driving, the maximum parallel driving force, and the maximum series driving force.

[0048] The parallel maximum driving force is the maximum driving force that the drive motor 10 can output using electricity supplied from the engine 12 and the drive battery 16, and is dependent on the battery state of the drive battery 16, such as current, voltage, and temperature. The series maximum driving force is the maximum driving force that the drive motor 10 can output using electricity generated by the generator 18 and electricity supplied from the drive battery 16, and is dependent on the power generation state of the generator 18, such as the generated torque.

[0049] For example, as shown in Figure 5, in PR driving with the low gear 64 selected in the transaxle 32, there is a speed (hereinafter referred to as the "PRLo upper limit vehicle speed") at which acceleration cannot be achieved without transitioning from PR driving to SR driving due to the rotational speed limit of the engine 12. In this case, it is necessary to offset the driving torque of the engine 12 with the generated torque of the generator 18 at the clutch shaft 20, bringing the torque on the clutch shaft close to 0 Nm. However, the generated torque of the generator 18 cannot be immediately used as the driving torque of the engine 12. Therefore, the increasing gradient of the generated torque of the generator 18 is set to a predetermined reference value. However, if the maximum parallel driving force is greater than the maximum series driving force, and the actual driving force during PR driving is greater than the maximum series driving force, a sudden decrease in driving force may occur.

[0050] Therefore, in the power generation torque setting unit 118 according to this embodiment, the increase gradient of the power generation torque is set based on the actual driving force during PR driving, the maximum parallel driving force, and the maximum series driving force. For example, at the upper limit vehicle speed of PRLo, the increase gradient of the power generation torque is set so that the actual driving force is less than the maximum series driving force.

[0051] Furthermore, as shown in Figure 6, for example, the power generation torque setting unit 118 reduces the increase gradient of the power generation torque to less than the aforementioned reference value when the maximum parallel driving force is greater than the maximum series driving force, and the actual driving force during PR driving is greater than the maximum series driving force. In this way, when the power generation torque setting unit 118 sets the increase gradient of the power generation torque to less than the aforementioned reference value, the actual driving force gradually decreases so that it becomes less than the maximum series driving force. Subsequently, by transitioning from PR driving to SR driving, it becomes possible to drive beyond the PRLo upper limit vehicle speed.

[0052] For example, as shown in Figure 7, the power generation torque setting unit 118 sets the increase gradient of the power generation torque to the aforementioned reference value when, at a preset determination vehicle speed, the maximum parallel driving force is greater than the maximum series driving force, and the actual driving force during PR driving is less than or equal to the maximum series driving force. In this way, when the power generation torque setting unit 118 sets the increase gradient of the power generation torque to the reference value, the actual driving force will not exceed the maximum series driving force. Subsequently, by transitioning from PR driving to SR driving, it becomes possible to drive beyond the PRLo upper limit vehicle speed.

[0053] [torque control device] Figure 8 is a flowchart illustrating the control contents of the torque control device 30 shown in Figure 5. As shown in Figure 8, the torque control device 30 according to Embodiment 1 determines whether or not the hybrid vehicle 1 is in PR driving mode (step S11). If the hybrid vehicle 1 is in PR driving mode (step S11: Yes), the maximum driving force calculation unit 116 calculates the parallel maximum driving force and the series maximum driving force (step S12). If the parallel maximum driving force is greater than the series maximum driving force (step S13: Yes), and the actual driving force during PR driving is greater than the series maximum driving force (step S14: Yes), the power generation torque setting unit 118 reduces the increase gradient of the power generation torque to less than the above-mentioned reference value (step S15).

[0054] On the other hand, if the maximum parallel driving force is greater than the maximum series driving force (Step S13: Yes), and the actual driving force during PR driving is less than or equal to the maximum series driving force (Step S14: No), the increase gradient of the generated torque is set to the reference value (Step S16).

[0055] [Effects of Hybrid Vehicles] According to the hybrid vehicle 1 of Embodiment 1, when transitioning from PR driving to SR driving, the increasing gradient of the generated torque is set based on the actual driving force during PR driving, the maximum parallel driving force, and the maximum series driving force, so that the generated torque gradually increases according to the increasing gradient. As a result, the driving torque of the engine 12 is gradually canceled out by the generated torque of the generator 18, and the electricity supplied from the generator 18 to the drive motor 10 gradually increases, thus avoiding a sudden drop in driving force. When the driving torque of the engine 12 is canceled out by the generated torque of the generator 18, the torque on the clutch shaft becomes 0 Nm, and the disengagement of the engine-side drive gear 26, which is meshed with the driven gear 22 on the drive wheel side, begins. When the drive gear 26 is disengaged from the driven gear 22, the power transmission from the engine 12 to the drive wheels 14 is cut off, and the vehicle transitions from PR driving to SR driving.

[0056] For example, as shown in Figure 9, when transitioning from PR driving to SR driving, if the increase gradient of the generated torque (GEN torque) is set to a predetermined reference value based on the actual driving force during PR driving, the maximum parallel driving force, and the maximum series driving force, the generated torque will gradually increase according to the increase gradient that becomes the reference value. As a result, the driving torque of the engine 12 is gradually canceled out by the generated torque of the generator 18, and the electricity supplied from the generator 18 to the drive motor 10 gradually increases. When the driving torque (ENG torque) of the engine 12 is canceled out by the generated torque of the generator 18, the torque on the clutch shaft becomes 0 Nm, and the disengagement of the engine-side drive gear 26, which is meshed with the driven gear 22 on the drive wheel side, begins. When the drive gear 26 is disengaged from the driven gear 22, the power transmission from the engine 12 to the drive wheels 14 is cut off, and the system transitions from PR driving to SR driving.

[0057] For example, as shown in Figure 10, when transitioning from PR driving to SR driving, if the maximum parallel driving force is greater than the maximum series driving force, and the actual driving force during PR driving is greater than the maximum series driving force, the increase gradient of the generated torque (GEN torque) becomes smaller than the reference value, and the generated torque gradually increases according to an increase gradient smaller than the reference value. Therefore, the driving torque (ENG torque) of the engine 12 is gradually canceled out by the generated torque of the generator 18, and the electricity supplied from the generator 18 to the drive motor 10 gradually increases. As a result, the driving force gradually decreases from the actual driving force during PR driving and eventually becomes the maximum series driving force, thus avoiding a sudden drop in driving force. When the driving torque of the engine 12 is canceled out by the generated torque of the generator 18, the torque on the clutch shaft becomes 0 Nm, and the engine-side drive gear 26, which is meshed with the driven gear 22 on the drive wheel side, begins to disengage. When the drive gear 26 is disengaged from the driven gear 22, the power transmission from the engine 12 to the drive wheels 14 is cut off, and the vehicle transitions from PR driving to SR driving.

[0058] Furthermore, for example, when transitioning from PR driving to SR driving, if the maximum parallel driving force is greater than the maximum series driving force, and the actual driving force during PR driving is less than or equal to the maximum series driving force, the increase gradient of the generated torque becomes a predetermined reference value, and the generated torque gradually increases according to the increase gradient that becomes the reference value. Therefore, the driving torque of the engine 12 is gradually canceled out by the generated torque of the generator 18, and the electricity supplied from the generator 18 to the drive motor 10 gradually increases. As a result, the transition from PR driving to SR driving is made while maintaining the actual driving force during PR driving, thus avoiding a sudden drop in driving force. When the driving torque of the engine 12 is canceled out by the generated torque of the generator 18, the torque on the clutch shaft becomes 0 Nm, and the engine-side drive gear 26, which is meshed with the driven gear 22 on the drive wheel side, begins to disengage. When the drive gear 26 is disengaged from the driven gear 22, the power transmission from the engine 12 to the drive wheels 14 is cut off, and the system transitions from PR driving to SR driving.

[0059] [Embodiment 2] [Hybrid vehicles] Figure 11 is a block diagram schematically showing the control configuration of the HEV-ECU 106 according to Embodiment 2. The hybrid vehicle and HEV-ECU according to Embodiment 2 have the same configuration as the hybrid vehicle 1 and HEV-ECU 106 according to Embodiment 1, except for the torque control unit 120. Therefore, the explanation of the configuration which is the same as the hybrid vehicle 1 and HEV-ECU 106 according to Embodiment 1 will be omitted.

[0060] [Torque control device] The torque control unit 120 (torque control device 30) according to Embodiment 2 includes, in addition to the maximum driving force calculation unit 116 and the power generation torque setting unit 118 described above, a required driving force calculation unit 122 that calculates the required driving force required for the hybrid vehicle 1. For example, the required driving force calculation unit 122 calculates the required driving force required for the hybrid vehicle 1 based on the vehicle speed measured by the speed sensor 110 and the accelerator opening detected by the APS 113.

[0061] In the power generation torque setting unit 118 according to this second embodiment, the increase gradient of the power generation torque is set based on the actual driving force during PR driving, the required driving force, the maximum parallel driving force, and the maximum series driving force.

[0062] For example, as shown in Figure 12, the power generation torque setting unit 118 increases the increase gradient of the power generation torque to a value greater than the aforementioned reference value when the maximum parallel driving force is less than or equal to the maximum series driving force, and the required driving force is greater than the maximum parallel driving force. In this way, when the power generation torque setting unit 118 is set to increase the increase gradient of the power generation torque to a value greater than the aforementioned reference value, the rate of increase of the power generation torque becomes faster.

[0063] Furthermore, for example, the power generation torque setting unit 118 sets the increase gradient of the power generation torque to the aforementioned reference value when the maximum parallel driving force is less than or equal to the maximum series driving force, and the required driving force is less than or equal to the maximum parallel driving force. In this way, when the power generation torque setting unit 118 sets the increase gradient of the power generation torque to the reference value, the power generation torque increases along the increase gradient that becomes the reference value.

[0064] [torque control device] Figure 13 is a flowchart that schematically shows the control contents of the torque control device 30 shown in Figure 12. As shown in Figure 13, the torque control device 30 according to Embodiment 2 increases the gradient of the generated torque above a reference value (Step S22) when, during PR driving, the maximum parallel driving force is less than or equal to the maximum series driving force (Step S13: No), and the required driving force is greater than the maximum parallel driving force (Step S21: Yes).

[0065] On the other hand, if the maximum parallel driving force is less than or equal to the maximum series driving force (Step S13: Yes), and the required driving force is less than or equal to the maximum parallel driving force (Step S21: No), the power generation torque setting unit 118 sets the increasing gradient of the power generation torque to a reference value (Step S16).

[0066] [Effects of Hybrid Vehicles] In the hybrid vehicle according to Embodiment 2, when transitioning from PR driving to SR driving, the increasing gradient of the generated torque is set based on the actual driving force during PR driving, the required driving force, the maximum parallel driving force, and the maximum series driving force, so that the generated torque gradually increases according to the increasing gradient. As a result, the driving torque of the engine 12 is gradually canceled out by the generated torque of the generator 18, and the electricity supplied from the generator 18 to the drive motor 10 gradually increases, thus avoiding a sudden drop in driving force. When the driving torque of the engine 12 is canceled out by the generated torque of the generator 18, the torque on the clutch shaft becomes 0 Nm, and the disengagement of the engine-side drive gear 26, which is meshed with the driven gear 22 on the drive wheel side, begins. When the drive gear 26 is disengaged from the driven gear 22, the power transmission from the engine 12 to the drive wheels 14 is cut off, and the vehicle transitions from PR driving to SR driving.

[0067] For example, as shown in Figure 14, when transitioning from PR driving to SR driving, if the maximum parallel driving force is less than or equal to the maximum series driving force, and the required driving force is greater than the maximum parallel driving force, the increase gradient of the generated torque becomes greater than the reference value, and the generated torque gradually increases in accordance with the increase gradient greater than the reference value. Therefore, the driving torque of the engine 12 is offset faster than when the increase gradient of the generated torque is at the reference value, and the torque on the clutch shaft becomes 0 Nm. As a result, the transition from PR driving to SR driving can be made faster than when the increase gradient of the generated torque is at the reference value.

[0068] Furthermore, for example, when transitioning from PR driving to SR driving, if the maximum parallel driving force is less than or equal to the maximum series driving force, and the required driving force for the hybrid vehicle is less than or equal to the maximum parallel driving force, the increase gradient of the generated torque becomes the reference value, and the generated torque gradually increases according to the reference increase gradient. Consequently, the driving torque of the engine 12 is gradually offset by the generated torque of the generator 18, and the electricity supplied from the generator 18 to the drive motor 10 gradually increases. This makes it possible to transition from PR driving to SR driving while gradually increasing the driving force from the actual driving force during PR driving towards the required driving force.

[0069] [Embodiment 3] [Hybrid vehicles] The hybrid vehicle 1, HEV-ECU 106, and torque control unit 114 according to Embodiment 3 have the same configuration as the hybrid, HEV-ECU 106, and torque control unit 114 according to Embodiment 1, except for the power generation torque setting unit 118. Therefore, the explanation of the same configuration as the hybrid vehicle 1, HEV-ECU 106, and torque control unit 114 according to Embodiment 1 will be omitted.

[0070] [Torque setting section] As shown in Figure 15, the power generation torque setting unit 118 according to Embodiment 3 increases the gradient of the power generation torque as the difference between the actual driving force and the series maximum driving force decreases when the parallel maximum driving force is greater than the series maximum driving force and the actual driving force during PR driving is greater than the series maximum driving force.

[0071] [Effects of Hybrid Vehicles] According to the hybrid vehicle 1 of Embodiment 3, when transitioning from PR driving to SR driving, if the maximum parallel driving force is greater than the maximum series driving force, and the actual driving force during PR driving is greater than the maximum series driving force, the smaller the difference between the actual driving force and the maximum series driving force, the greater the gradient of increase in generated torque. As a result, the generated torque gradually increases in accordance with the gradient of increase in generated torque, which increases as the difference between the actual driving force and the maximum series driving force decreases, until the torque on the clutch shaft becomes 0 Nm. This makes it possible to transition from PR driving to SR driving while suppressing the decrease in actual driving force.

[0072] The present invention is not limited to the embodiments described above, and includes modified forms of the embodiments described above, as well as forms that combine these forms as appropriate. [Explanation of symbols]

[0073] 1. Hybrid vehicle 10 Drive motor 12 Engines 14. Drive wheels (front wheels) 16 Power Battery 18 Generators 20 Clutch shaft 22,24 Driven gear 26 drive gears 28 Engine Clutch 30 Torque control device 32 transaxle 34. Drive axle (wheel axle) 36 Transmission 38 Final Drive 40 Power transmission path (motor power transmission path) 42 Power transmission path (engine power transmission path) 44 Final Gear 46 Differential Gear 48 Motor Clutch 50 Clutch shaft 52 Driven disk 54 Drive disk 56 Drive gear 58 Motor Gear 60 Driven gear 62. First Actuator (ACT1) 64 Low gears 66 high gears 68 Small diameter gear 70 Large Diameter Gear 72 Large Diameter Gear 74 Small diameter gear 76 Counter axis 78 Counter Gear 80 Second Actuator (ACT2) 82 Power transmission path (generator power transmission path) 84 Drive Gear 86 Generator Gear 88 Motor Control Unit (Motor ECU) 90 Fuel Tank 92 Engine Control Unit (Engine ECU) 94 Battery Control Unit (Battery ECU) 96 Current Sensor 98 Voltage Sensor 100 Temperature Sensor 102 Generator Control Unit (Generator ECU) 104 Clutch Control Unit (Clutch ECU) 106 Vehicle Control Unit (HEV-ECU) 108. Vehicle Control Unit (Vehicle ECU) 110 Speed ​​Sensor 112 Wheel speed sensor 113 Accelerator Position Sensor (APS) 114 Torque Control Unit 116 Maximum driving force calculation unit 118 Power generation torque setting section 120 Torque Control Unit 122 Request driving force calculation unit

Claims

1. A hybrid vehicle in which the drive wheels are driven by at least one of a drive motor or an engine, A drive battery that supplies electricity to the drive motor, A generator driven by the engine and supplying electricity to at least one of the drive motor or the drive battery, A clutch shaft provided between the drive wheel and the engine includes an engine clutch that disconnects the drive gear on the engine side from the driven gear on the drive wheel side, thereby interrupting the transmission of power from the engine to the drive wheel. When the drive gear is disengaged from the driven gear, a torque control device controls the generator's generated torque on the clutch shaft so that the generator's generated torque cancels out the engine's driving torque. Equipped with, The torque control device is A maximum driving force calculation unit calculates the maximum parallel driving force that can be output during parallel operation when the drive gear is meshed with the driven gear, and the maximum series driving force that can be output during series operation when the drive gear is disconnected from the driven gear. A power generation torque setting unit sets the increasing gradient of the power generation torque based on the actual driving force during parallel driving, the maximum parallel driving force, and the maximum series driving force. Hybrid vehicles, including those mentioned above.

2. The power generation torque setting unit reduces the increase gradient of the power generation torque to a predetermined reference value when the maximum parallel driving force is greater than the maximum series driving force, and the actual driving force during parallel driving is greater than the maximum series driving force. The hybrid vehicle according to claim 1.

3. The power generation torque setting unit sets the increase gradient of the power generation torque to the reference value when the maximum parallel driving force is greater than the maximum series driving force, and the actual driving force during parallel driving is less than or equal to the maximum series driving force. The hybrid vehicle according to claim 2.

4. The torque control device includes a required driving force calculation unit that calculates the required driving force required for the hybrid vehicle, The power generation torque setting unit increases the gradient of the power generation torque to a value greater than the reference value when the maximum parallel driving force is less than or equal to the maximum series driving force, and the required driving force is greater than the maximum parallel driving force. The hybrid vehicle according to claim 2 or 3.

5. The power generation torque setting unit sets the increasing gradient of the power generation torque to the reference value when the maximum parallel driving force is less than or equal to the maximum series driving force, and the required driving force is less than or equal to the maximum parallel driving force. The hybrid vehicle according to claim 4.

6. The power generation torque setting unit increases the gradient of the power generation torque as the difference between the actual driving force and the series maximum driving force decreases, when the parallel maximum driving force is greater than the series maximum driving force and the actual driving force during parallel driving is greater than the series maximum driving force. A hybrid vehicle according to claim 1 or 2.

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