vehicle

Abstract

The aim was to improve drivability by suppressing the loss of driving force that occurs when restarting the engine with the output side connected. [Solution] Vehicle V is equipped with an internal combustion engine 3 and an electric motor 4, and controls the switching of these drive sources. It has an input shaft 13 that transmits power from the internal combustion engine 3, an electric motor connection shaft 60 connected to the electric motor 4, and an output shaft 15 that transmits power to the drive wheels. Furthermore, it is equipped with a switching mechanism 70 that switches the power transmission path between the electric motor connection shaft 60 and the input shaft 13, or between the electric motor connection shaft 60 and the output shaft 15, and a clutch 50 that transmits rotation from the input shaft 13 to the output shaft 15. When restarting the internal combustion engine 3 while driving with the output side connected, the torque capacity of the clutch 50 is gradually increased, and the output torque of the electric motor 4 is increased in conjunction with this.

Description

TECHNICAL FIELD

[0001] The present invention relates to a vehicle that includes an internal combustion engine and an electric motor, and that changes a traveling mode by performing switching control of drive sources of the internal combustion engine and the electric motor.

BACKGROUND ART

[0002] Conventionally, hybrid vehicles equipped with an electric motor (motor) and an internal combustion engine (engine) are known. In such hybrid vehicles, one or both of the electric motor and the internal combustion engine are used as a drive source. In particular, in a hybrid vehicle including a drive unit of a parallel hybrid mechanism, the motor can be caused to function as a starter, a generator, and a drive source by switching a power transmission path of the motor.

[0003] For example, there is a method in which the motor and the output shaft are directly connected via a power transmission path that directly connects the motor connection shaft and the output shaft, and a forward-reverse clutch and a lock-up clutch are engaged to apply rotation to the crankshaft to perform restarting. This method is positively adopted from the viewpoint of drivability because no drop in driving force occurs during restarting.

PRIOR ART DOCUMENTS

PATENT DOCUMENTS

[0004]

PATENT DOCUMENT 1

SUMMARY OF INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0005] However, when the internal combustion engine is restarted in a state where the electric motor connection shaft and the output shaft are directly connected as described above, the power of the motor is used for both traveling and starting. At this time, when inertia torque and friction loss torque of the engine are generated, the vehicle driving force is lost by that amount, and there arises a problem that a deceleration sensation occurs at the time of restarting.

[0006] Therefore, the present invention aims to suppress the loss of driving force that occurs when restarting the engine with the output side connected, and to improve drivability. [Means for solving the problem]

[0007] (1) The present invention, provided to solve the above-mentioned problems, is a vehicle equipped with an internal combustion engine and an electric motor, which changes the driving mode by switching control between the drive sources of the internal combustion engine and the electric motor, and is characterized in that, when the vehicle is running in the output-side connection state, the torque capacity of the clutch is gradually increased and the output torque of the electric motor is increased in conjunction with the increase in the torque capacity of the clutch, when the vehicle is restarted in response to a request to start the internal combustion engine while the vehicle is running in the output-side connection state, the torque capacity of the clutch is gradually increased and the output torque of the electric motor is increased in conjunction with the increase in the torque capacity of the clutch.

[0008] As described in (1) above, the vehicle of the present invention is configured such that when restarting the internal combustion engine in an output-side connected state that enables the transmission of power between the motor connection shaft and the output shaft, the torque capacity of the clutch is gradually increased, and the output torque of the motor is increased in conjunction with the increase in the torque capacity of the clutch.

[0009] This configuration prevents clutch shock during engagement by gradually increasing the clutch's torque capacity when restarting the internal combustion engine with the output side engaged. Furthermore, by increasing the motor's output torque in conjunction with the increase in clutch torque capacity, the loss of vehicle driving force due to inertia torque and friction loss torque generated during engine restart can be offset. This suppresses acceleration changes that occur during engine restart with the output side engaged, resulting in improved drivability.

[0010] Here, the output-side connection state refers to a state in which power can be transmitted between, for example, the motor connection shaft and the output shaft. In this state, the power of the motor is transmitted to the output shaft via the motor connection shaft. On the other hand, the input-side connection state refers to a state in which power can be transmitted between, for example, the motor connection shaft and the input shaft.

[0011] (2) The vehicle of the present invention is characterized in that the clutch is at least one of a forward clutch and a reverse clutch.

[0012] As described in (2) above, the vehicle of the present invention is configured such that the clutch is at least one of a forward clutch and a reverse clutch.

[0013] This configuration allows for the prevention of shocks during engine restart while simultaneously offsetting losses in vehicle drive force by controlling either the forward or reverse clutch. For example, the torque capacity of the forward clutch can be controlled during forward driving, and the torque capacity of the reverse clutch can be controlled during reverse driving. This effectively suppresses fluctuations in drive force during engine restart in both forward and reverse driving conditions.

[0014] (3) In the vehicle of the present invention, the torque capacity of the clutch is calculated based on the hydraulic pressure supplied to the clutch.

[0015] As described in (3) above, the vehicle of the present invention is configured such that the torque capacity of the clutch is calculated based on the hydraulic pressure supplied to the clutch.

[0016] This configuration allows for accurate determination of the clutch's torque capacity by utilizing the correlation between the hydraulic pressure supplied to the clutch and the clutch's torque capacity. This enables appropriate control of the motor's output torque increase in conjunction with the increase in the clutch's torque capacity, resulting in a more effective suppression of fluctuations in driving force during the restart of the internal combustion engine.

[0017] (4) In the vehicle of the present invention, the torque capacity of the clutch is calculated based on the hydraulic pressure supplied to the clutch detected by a hydraulic sensor.

[0018] As described in (4) above, the vehicle of the present invention is configured such that the torque capacity of the clutch is calculated based on the hydraulic pressure supplied to the clutch, which is detected by a hydraulic sensor.

[0019] This configuration allows for a more accurate determination of the clutch's torque capacity by directly detecting the hydraulic pressure actually supplied to the clutch using a hydraulic sensor. This improves the accuracy of the control of increasing the output torque of the electric motor in conjunction with the increase in the clutch's torque capacity, resulting in a more effective suppression of fluctuations in driving force when the internal combustion engine is restarted.

[0020] (5) The vehicle of the present invention is characterized in that the torque capacity of the clutch is calculated based on a target value for the torque capacity of the clutch.

[0021] As described in (5) above, the vehicle of the present invention is configured such that the torque capacity of the clutch is calculated based on a target value for the torque capacity of the clutch.

[0022] With this configuration, even if a hydraulic sensor is not installed or there is a response delay in the sensor value, the torque capacity of the clutch can be appropriately estimated by using the target value of the clutch torque capacity. As a result, regardless of the presence or absence of a sensor, the effect of suppressing fluctuations in driving force when restarting the internal combustion engine can be obtained. Furthermore, by using both the detected value of the hydraulic sensor and the target value, it becomes possible to estimate the torque capacity with higher accuracy, resulting in improved control reliability.

[0023] (6) The vehicle of the present invention is characterized in that when the internal combustion engine is restarted, control is also performed to shift the belt gear ratio of the continuously variable transmission to the high gear side.

[0024] The vehicle of the present invention is configured to additionally execute control for shifting the belt speed ratio of the continuously variable transmission to the high gear side when restarting the internal combustion engine, as described in the above (6).

[0025] According to this configuration, power transmission from the electric motor to the internal combustion engine can be performed more efficiently. In the output-side connected state, the power of the electric motor is transmitted from the output shaft side to the input shaft side, so it is advantageous to set the belt speed ratio to the high gear side. As a result, the output torque of the electric motor required to rotate the internal combustion engine can be reduced, and the internal combustion engine can be restarted efficiently while suppressing an increase in the output torque of the electric motor. As a result, the energy consumption of the electric motor can be reduced, and the effect of avoiding the constraint due to the upper limit of the output torque of the electric motor can be obtained.

[0026] The configurations of the above (1) to (6) can be arbitrarily combined. In particular, by combining the configurations (3) to (5) relating to the method of calculating the torque capacity of the clutch and the configuration (6) relating to the belt speed ratio control of the continuously variable transmission, it is possible to obtain the effect of reducing the energy consumption of the electric motor while more effectively suppressing the driving force fluctuation at the time of restarting the internal combustion engine.

Effects of the Invention

[0027] According to the present invention, it is possible to provide a vehicle capable of suppressing driving force loss that occurs when the engine is restarted in the output-side connected state and improving drivability.

Brief Description of the Drawings

[0028] [Figure 1] This is an overall front view of the vehicle according to one embodiment of the present invention, with the transmission cover cut away. [Figure 2] This is a skeleton diagram of one embodiment of the transmission in Figure 1. [Figure 3] This is a block diagram showing the configuration of a control system included in the vehicle according to one embodiment of the present invention. [Figure 4] This is a flowchart relating to the internal combustion engine restart control performed in a vehicle according to one embodiment of the present invention. [Modes for carrying out the invention]

[0029] The following describes in detail a vehicle V and a transmission 10 mounted thereon according to one embodiment of the present invention, with reference to the drawings. Note that the figures are schematic representations for ease of understanding and may differ from the actual shape, size, and arrangement of components. Also note that the fact that each shaft is supported by appropriate bearings and is rotatable may be omitted. Furthermore, in the following, the front side of the vehicle V may be referred to as the front Fr and the rear side as the rear Rr.

[0030] ≪Basic Configuration of a Transmission≫ As shown in Figures 1 and 2, vehicle V is equipped with an internal combustion engine 3, an electric motor 4, and a battery 6, and changes the driving mode by switching the power source of the internal combustion engine 3 and the electric motor 4. Vehicle V is equipped with a transmission 10, to which the internal combustion engine 3 and the electric motor 4 are connected.

[0031] The internal combustion engine 3 is composed of, for example, a gasoline engine or a diesel engine. The drive shaft (not shown) of the internal combustion engine 3 is connected to the input shaft 13 of the transmission 10. Therefore, the power output by the internal combustion engine 3 is input to the transmission 10 through the input shaft 13.

[0032] As shown in Figures 1 and 2, the electric motor 4 is configured, for example, as a motor generator, and can output driving force and generate electricity. The motor shaft 4A of the electric motor 4 is connected to the motor connection shaft 60 in the transmission 10 via a universal joint 5. Therefore, the power output by the electric motor 4 is input to the transmission 10 via the motor connection shaft 60.

[0033] The transmission 10 has multiple gears and is configured to change the speed of the power generated by the internal combustion engine 3 and the electric motor 4, and to transmit the regenerated energy to the electric motor 4.

[0034] As shown in Figures 1 and 2, the transmission 10 includes a torque converter 12, an input shaft 13, a continuously variable transmission 20 (CVT 20), a reverse transmission mechanism 40, a forward clutch 51 (clutch device 50), a reverse clutch 55 (clutch device 50), and an output shaft 15. The transmission 10 also includes an electric motor connecting shaft 60, a primary shaft 21, a secondary shaft 23, a first driven shaft 30, a second driven shaft 35, a reverse idler shaft 41, and a switching mechanism 70, etc.

[0035] As shown in Figures 1 and 2, the torque converter 12 includes a pump impeller 12A, a turbine runner 12B, and a lock-up mechanism 12C (lock-up clutch), etc. The input shaft 13 is connected to the pump impeller 12A and is able to rotate integrally with the input shaft 13 around the same axis of rotation. The turbine runner 12B is rotatable around the same axis of rotation as the pump impeller 12A.

[0036] The lock-up mechanism 12C is provided to directly connect / disconnect the pump impeller 12A and the turbine runner 12B. When the lock-up mechanism 12C is engaged (lock-up on), the pump impeller 12A and the turbine runner 12B are directly connected, and when the lock-up mechanism 12C is released (lock-up off), the pump impeller 12A and the turbine runner 12B are separated.

[0037] The input shaft 13 is positioned so that its axis coincides with the rotation axis of the torque converter 12. The input shaft 13 can transmit power output from the internal combustion engine 3. An input shaft gear 14 is integrally formed on the input shaft 13. The front end Fr of the input shaft 13 is inserted into the torque converter 12.

[0038] The output shaft 15 is positioned at a rearward (Rr) distance from the input shaft 13. The output shaft 15 is positioned so that its axis aligns with the axis of the input shaft 13. Although not shown in the illustration, the output shaft 15 can transmit power to the drive wheels of the vehicle V via a drive shaft or the like. An output shaft gear 16 is integrally formed on the output shaft 15.

[0039] The continuously variable transmission 20 is provided with a primary shaft 21, a secondary shaft 23, a primary pulley 26, a secondary pulley 27, and a belt 28. A primary input gear 22 (also called a driven gear 22) is mounted on the primary shaft 21 so as to be rotatable relative to it. The primary input gear 22 meshes with an input shaft gear 14 and a second driven gear 36, which will be described later.

[0040] A secondary input gear 24 and a secondary output gear 25 are mounted on the secondary shaft 23. The secondary input gear 24 is rotatable relative to the secondary shaft 23. The secondary output gear 25 is mounted so as not to rotate relative to the secondary shaft 23. The secondary output gear 25 meshes with an output shaft gear 16 provided on the output shaft 15.

[0041] In the continuously variable transmission 20, a belt 28 is stretched between a primary pulley 26 and a secondary pulley 27. In the continuously variable transmission 20, the hydraulic pressure supplied to the hydraulic chambers (not shown) of the primary pulley 26 and the secondary pulley 27 is controlled, and the groove widths of the primary pulley 26 and the secondary pulley 27 are changed, thereby continuously changing the belt gear ratio (pulley ratio between the primary pulley 26 and the secondary pulley 27) within a constant gear ratio range. The rotational force (power) of the shifted secondary shaft 23 is transmitted to the output shaft 15 via the secondary output gear 25 and the output shaft gear 16, driving the drive wheels (not shown).

[0042] The reverse transmission mechanism 40 is a mechanism that transmits power (rotation) from the input shaft 13 to the secondary input gear 24. The reverse transmission mechanism 40 is equipped with a reverse idler shaft 41 and reverse idler gears 42 (first reverse idler gear 42A and second reverse idler gear 42B).

[0043] The reverse idler shaft 41 is a shaft located midway between the secondary shaft 23 and the first driven shaft 30, which will be described later. As shown in Figure 1, the reverse idler shaft 41 is rotatably supported at both ends by a front bearing 44 and a rear bearing 46. The front bearing 44 and the rear bearing 46 are each held in the transmission case 10A. The front bearing 44 is located at the end of the reverse idler shaft 41 on the side of the first reverse idler gear 42A. The rear bearing 46 is located at the end on the side of the second reverse idler gear 42B.

[0044] As shown in Figures 1 and 2, the first reverse idler gear 42A is integrally formed with the reverse idler shaft 41 and meshes with the input shaft gear 14. In other words, the first reverse idler gear 42A can reverse the rotation direction of the input shaft gear 14 (input shaft 13).

[0045] The second reverse idler gear 42B is formed integrally with the reverse idler shaft 41 at the rear Rr of the first reverse idler gear 42A and meshes with the secondary input gear 24.

[0046] The forward clutch 51 (clutch device 50) is provided to allow / prevent the rotation of the primary input gear 22 relative to the primary shaft 21. The forward clutch 51 forms a clutch device 50 that includes a clutch drum, clutch piston, friction material, and hydraulic chamber, although these are not shown in the figures. The forward clutch 51 controls the engagement of the clutch by controlling the supply of oil to the hydraulic chamber according to the output value of a solenoid (not shown).

[0047] When the forward clutch 51 is engaged (engaged state), relative rotation of the primary input gear 22 with respect to the primary shaft 21 is prohibited. In other words, the engagement of the forward clutch 51 causes the primary shaft 21 and the primary input gear 22 to rotate as a single unit. As a result, a driving force in the forward direction is transmitted to the output shaft 15 via the continuously variable transmission 20, and the drive wheels (not shown) are driven in the forward direction.

[0048] The reverse clutch 55 (clutch device 50) is provided to allow / prevent the rotation of the secondary input gear 24 relative to the secondary shaft 23. The reverse clutch 55 has the same configuration as the forward clutch 51.

[0049] When the reverse clutch 55 is engaged (engaged state), relative rotation of the secondary input gear 24 with respect to the secondary shaft 23 is prohibited. In other words, the engagement of the reverse clutch 55 causes the secondary shaft 23 and the secondary input gear 24 to rotate together. This transmits a driving force in the reverse direction to the output shaft 15, and drives the drive wheels (not shown) in the reverse direction. On the other hand, when the reverse clutch 55 is released (released state), relative rotation of the secondary input gear 24 with respect to the secondary shaft 23 is permitted. Therefore, even if the secondary input gear 24 rotates, that rotation is not transmitted to the secondary shaft 23.

[0050] The motor connecting shaft 60 has a first motor connecting shaft 60A and a second motor connecting shaft 60B (hereinafter, the first motor connecting shaft 60A may be referred to as the front end side (Fr side) of the motor connecting shaft 60, and the second motor connecting shaft 60B may be referred to as the rear end side (Rr side) of the motor connecting shaft 60). As shown in Figures 1 and 2, a universal joint 5 is connected to the front end (front Fr side / first motor connecting shaft 60A) of the motor connecting shaft 60. The motor shaft 4A of the electric motor 4 (for example, a motor generator) is connected to the front end side (Fr side) of the universal joint 5. In addition, a motor connecting shaft gear 61, an output side gear 33, a switching mechanism 70, and the second motor connecting shaft 60B are provided on the axis of the first motor connecting shaft 60A.

[0051] The motor connecting shaft gear 61 is located on the first motor connecting shaft 60A, which is on the front end (front Fr side) of the motor connecting shaft 60. The motor connecting shaft gear 61 has an outer sleeve shape and is connected to a clutch 71 which is part of the switching mechanism 70. The motor connecting shaft gear 61 is designed so that the motor connecting shaft 60 and the motor connecting shaft gear 61 can rotate synchronously when the switching mechanism 70 is in a state that enables power transmission between the motor connecting shaft 60 and the input shaft 13 (input side connection state), as will be described in detail later. The motor connecting shaft gear 61 meshes with the third driven gear 32A on the first driven shaft 30. Therefore, when the motor 4 is driven, the power output from the motor 4 is transmitted to the first driven shaft 30. As will be described in more detail later, when the first driven shaft 30 is driven by the internal combustion engine 3, the power output from the internal combustion engine 3 is transmitted to the first driven shaft 30 and then used to generate electricity for the electric motor 4 via the motor connecting shaft gear 61 and the motor connecting shaft 60.

[0052] As shown in Figure 2, the first driven shaft 30 is provided between the motor connection shaft 60 and the input shaft 13. The first driven shaft 30 is rotatably supported at both its front end (front Fr side) and rear end (rear Rr side). A first driven gear 32 is also fixed to the middle of the first driven shaft 30.

[0053] The first driven gear 32 comprises a third driven gear 32A and a fourth driven gear 32B located on the rear side (Rr) of the third driven gear 32A.

[0054] The third driven gear 32A meshes with the motor connection shaft gear 61. Therefore, the first driven shaft 30 can transmit the power output from the motor connection shaft 60.

[0055] The fourth driven gear 32B is located on the opposite side of the first driven shaft 30 from the internal combustion engine 3 side (towards the transmission 10 side) in the axial direction of the first driven shaft 30. The fourth driven gear 32B meshes with the second driven gear 36, which is fixed to the second driven shaft 35, which will be described later.

[0056] As shown in Figures 1 and 2, the second driven shaft 35 is positioned parallel to the first driven shaft 30, with a gap between them. The second driven gear 36 is mounted to the second driven shaft 35.

[0057] The second driven gear 36 meshes with the primary input gear 22 (driven gear 22) and the fourth driven gear 32B. Therefore, when the clutch 71 of the switching mechanism 70 is in the "input side engaged state", the second driven gear 36 can rotate together with the second driven shaft 35 in accordance with the rotation of the primary input gear 22. That is, the power output from the internal combustion engine 3 is transmitted to the motor connection shaft 60 via the primary input gear 22, the second driven shaft 35, and the first driven shaft 30, and is used for generating electricity in the motor 4. Also, the second driven gear 36 can rotate together with the second driven shaft 35 in accordance with the rotation of the first driven shaft 30. That is, the power output from the motor 4 is transmitted to the first driven shaft 30, the second driven shaft 35, and the input shaft 13, and is used for starting the internal combustion engine 3.

[0058] The output gear 33 is fixed to the second motor connecting shaft 60B. The output gear 33 meshes with the output transmission shaft gear 18 (also called the output idler gear 18), which is fixed to the output transmission shaft 17 (described later). (Note that although the diagram shows the output gear 33 and the output transmission shaft 17 as being separated, they are actually meshed with each other.)

[0059] The output transmission shaft 17 is mounted parallel to the motor connection shaft 60, with a gap between them. An output transmission shaft gear 18 is mounted on the output transmission shaft 17. The output transmission shaft gear 18 meshes with the output shaft gear 16 on the output shaft 15. The output transmission shaft gear 18 also meshes with the output side gear 33 on the first driven shaft 30. The output transmission shaft gear 18 also meshes with the output shaft gear 16 on the output shaft 15. Therefore, the output transmission shaft 17 can transmit power from the first driven shaft 30 to the output shaft 15 as the first driven shaft 30 rotates.

[0060] The switching mechanism 70 is located between the first motor connecting shaft 60A and the second motor connecting shaft 60B. The switching mechanism 70 includes a clutch 71 and the like.

[0061] The switching mechanism 70 can switch between an "input-side connection state" that enables power transmission between the motor connection shaft 60 and the input shaft 13, and an "output-side connection state" that enables power transmission between the motor connection shaft 60 and the output shaft 15, by switching the connection state of the clutch 71 by hydraulics or the like. Specifically, the motor connection shaft 60 is divided into a first motor connection shaft 60A and a second motor connection shaft 60B via the clutch 71 of the switching mechanism 70. The first motor connection shaft 60A is equipped with a motor connection shaft gear 61, and the second motor connection shaft 60B is equipped with an output-side gear 33.

[0062] Therefore, in the "input-side connected state," the second motor connecting shaft 60B is not connected (the rear Rr side of the clutch 71 is not engaged), and only the first motor connecting shaft 60A rotates. That is, the motor connecting shaft gear 61 (input-side gear 61) rotates in conjunction with the rotation of the first motor connecting shaft 60A. Therefore, when the internal combustion engine 3 is driven in the "input-side connected state," the power output from the internal combustion engine 3 is used to generate electricity for the motor 4 via the input shaft 13, primary shaft 21, second driven shaft 35, first driven shaft 30, and motor connecting shaft 60. On the other hand, when the internal combustion engine 3 is stopped in the "input-side connected state," the power output from the motor 4 is used to start the internal combustion engine 3 via the motor connecting shaft 60, first driven shaft 30, second driven shaft 35, primary shaft 21, and input shaft 13.

[0063] Furthermore, in the "output-side connected state," the clutch 71 engages, connecting the second motor connecting shaft 60B, causing the first motor connecting shaft 60A and the second motor connecting shaft 60B to rotate together. Therefore, when the motor 4 is driven in the "output-side connected state," the power output from the motor 4 is used to drive the drive wheels (not shown) via the first motor connecting shaft 60A and the second motor connecting shaft 60B (EV driving state or assisted driving (HEV driving) state). On the other hand, when the drive wheels are braked (decelerated) in the "output-side connected state," the braking force acting on the output shaft 15 is used for regeneration (power generation) of the motor 4 via the motor connecting shaft 60.

[0064] Vehicle control system configuration As shown in Figure 3, vehicle V is equipped with a control system 100. The control system 100 includes an ECU (Electronic Control Unit) 101, which is a control device. The ECU 101 is composed of a microcomputer equipped with a CPU (Central Processing Unit) 102, RAM (Random Access Memory) 103, and ROM (Read Only Memory) 104, etc.

[0065] The ECU 101 receives detection signals from various sensors. Specifically, the ECU 101 receives detection signals from the accelerator pedal position sensor 111, vehicle speed sensor 112, engine speed sensor 113, battery charge sensor 114, clutch hydraulic pressure sensor 115, and others. The ECU 101 can also output control signals to the internal combustion engine 3, electric motor 4, clutch device 50 (forward clutch 51, reverse clutch 55), switching mechanism 70, and continuously variable transmission 20.

[0066] The accelerator pedal position sensor 111 detects the amount the accelerator pedal is pressed. The vehicle speed sensor 112 detects the vehicle speed from the rotational speed of the output shaft 15. The engine speed sensor 113 detects the rotational speed of the internal combustion engine 3. The battery charge sensor 114 detects the remaining charge of the battery 6. The clutch hydraulic pressure sensor 115 detects the hydraulic pressure supplied to the clutch device 50. The clutch hydraulic pressure sensor 115 is provided on at least one of the forward clutch 51 and the reverse clutch 55.

[0067] ≪Overall Overview of the Control Flow≫ The ECU101 controls the driving mode according to the driving conditions based on detection signals from various sensors. For example, the ECU101 switches between the internal combustion engine 3 and the electric motor 4 as the drive source based on the accelerator opening, vehicle speed, battery level, etc.

[0068] Examples of driving modes for vehicle V include an engine driving mode using only the internal combustion engine 3 as the power source, an electric motor driving mode (EV driving mode) using only the electric motor 4 as the power source, and a hybrid driving mode (HEV driving mode) using both the internal combustion engine 3 and the electric motor 4 as power sources.

[0069] In electric motor driving mode, the ECU 101 controls the switching mechanism 70 to an output-side connection state that enables power transmission between the motor connection shaft 60 and the output shaft 15. In this state, a power transmission path is formed in which the power of the electric motor 4 is transmitted to the output shaft 15 via the motor connection shaft 60, the output-side gear 33, the output transmission shaft gear 18, and the output shaft gear 16.

[0070] When the ECU101 detects a request to start the internal combustion engine while the vehicle is in electric motor driving mode, it performs control to restart the internal combustion engine 3. Examples of requests to start the internal combustion engine include when the accelerator opening exceeds a predetermined value, when the vehicle speed exceeds a predetermined value, when the battery level falls below a predetermined value, or when the internal combustion engine 3 needs to be warmed up.

[0071] Figure 4 is a flowchart of the restart control of the internal combustion engine 3 when the output side is connected. The ECU 101 performs the following steps S1 to S6 in order, according to the flowchart shown in Figure 4, as internal combustion engine restart control.

[0072] When restarting the internal combustion engine 3 while the output side is connected, the ECU 101 first detects an internal combustion engine start request (step S1). As described above, the internal combustion engine start request is determined based on conditions such as accelerator opening, vehicle speed, and battery level.

[0073] Subsequently, the ECU 101 confirms that the vehicle V is running in the output-side connected state (step S2). Here, the output-side connected state refers to a state in which power can be transmitted between the motor connection shaft 60 and the output shaft 15 by the switching mechanism 70. Once it is confirmed in step S2 that the vehicle V is running in the output-side connected state, the control flow proceeds to step S3.

[0074] In step S3, the ECU 101 initiates control to gradually increase the clutch torque capacity (gradual torque capacity increase control). The ECU 101 gradually increases the torque capacity of the clutch device 50. Specifically, the gradual torque capacity increase control is performed by gradually increasing the torque capacity of the forward clutch 51 or the reverse clutch 55. By gradually increasing the torque capacity of the clutch device 50 in this way, the shock when the clutch engages is suppressed.

[0075] Furthermore, the torque capacity of the clutch device 50 changes according to the hydraulic pressure supplied to the clutch. That is, the higher the clutch hydraulic pressure, the greater the torque capacity of the clutch device 50. Therefore, in step S3, the ECU 101 can gradually increase the torque capacity of the clutch device 50 by gradually increasing the clutch hydraulic pressure. After that, the control flow proceeds to step S4.

[0076] In step S4, the ECU 101 starts controlling the motor output torque increase. The ECU 101 increases the output torque of the motor 4 in conjunction with increasing the torque capacity of the clutch device 50. Specifically, it increases the output torque of the motor 4 in proportion to the increase in the torque capacity of the clutch device 50.

[0077] When restarting the internal combustion engine 3, if rotational force is transmitted to the engine 3 via the clutch, inertial torque is generated at the start of rotation of the engine 3 due to inertial force. In addition, friction loss torque is generated due to the internal friction of the engine 3. These torques are lost from the driving force of the vehicle V, and as a result, a feeling of deceleration may occur when restarting.

[0078] Therefore, in this embodiment, the output torque of the electric motor 4 is increased in conjunction with the increase in the torque capacity of the clutch device 50, thereby offsetting the loss of vehicle driving force associated with restarting the internal combustion engine 3. This makes it possible to suppress fluctuations in the driving force of the vehicle V when the internal combustion engine 3 is restarted.

[0079] Specifically, the ECU 101 sets the torque capacity of the clutch device 50 to Tc, and increases the output torque of the electric motor 4 from Tm0 to Tm0 + ΔTm in accordance with this torque capacity. Here, Tm0 is the basic output torque of the electric motor 4, and ΔTm is the torque increase. The torque increase ΔTm is determined based on the torque capacity Tc of the clutch device 50. For example, the torque increase ΔTm is set to be proportional to the torque capacity Tc of the clutch device 50.

[0080] As described above, once the motor output torque increase control is performed in step S4, the ECU 101 monitors the rotational speed of the internal combustion engine 3 in step S5. As the torque capacity of the clutch device 50 increases, the rotational speed of the internal combustion engine 3 begins to increase.

[0081] In step S6, the ECU 101 determines whether the rotational speed of the internal combustion engine 3 has reached a predetermined value, and if it has reached the predetermined value, it switches to normal control (step S7). Once the rotational speed of the internal combustion engine 3 stabilizes, the ECU 101 fully engages the clutch device 50 and adjusts the output torque of the electric motor 4 to a value corresponding to the normal driving conditions.

[0082] The above control steps compensate for the loss of driving force in the vehicle V during the restart of the internal combustion engine 3, thereby achieving a smooth restart.

[0083] ≪Method for Calculating Clutch Torque Capacity≫ The torque capacity of the clutch device 50 can be calculated in various ways. In this embodiment, the torque capacity of the clutch device 50 is calculated based on the hydraulic pressure supplied to the clutch.

[0084] One method involves calculating the torque capacity of the clutch device 50 using the hydraulic pressure detected by the clutch hydraulic pressure sensor 115. The clutch hydraulic pressure sensor 115 can directly detect the hydraulic pressure supplied to the clutch device 50. The ECU 101 calculates the torque capacity of the clutch device 50 based on the detection signal from the clutch hydraulic pressure sensor 115.

[0085] Specifically, the torque capacity Tc of the clutch device 50 can be calculated using the clutch hydraulic pressure P, a coefficient k, and a constant α, based on a formula such as the following: Tc = k × P + α Here, the coefficient k and the constant α are values ​​set according to the characteristics of the clutch device 50.

[0086] As a second method, if the clutch hydraulic sensor 115 is not provided, or if there is a response delay in the sensor value, a target value for the torque capacity of the clutch device 50 can be used. The ECU 101 sets a target value for the torque capacity when controlling the clutch device 50. By using this target value, the torque capacity of the clutch device 50 can be estimated without using a sensor.

[0087] These methods can also be combined. For example, both the detected value and the target value of the clutch hydraulic sensor 115 can be used to estimate the torque capacity with greater accuracy. This allows for compensation for the effects of the response delay of the clutch hydraulic sensor 115.

[0088] <<Supplementary control: CVT belt gear ratio control>> In restarting the internal combustion engine 3, the ECU 101 can perform control to increase the torque capacity of the clutch device 50 and increase the output torque of the electric motor 4, as well as control to shift the belt gear ratio of the continuously variable transmission 20 to the higher gear side.

[0089] When transmitting power from the motor connection shaft 60 to the input shaft 13, setting the belt gear ratio of the continuously variable transmission 20 to the high gear side allows for more efficient power transmission from the motor 4 to the internal combustion engine 3. This is because, in the output-side connection state, the power of the motor 4 is transmitted from the output shaft side to the input shaft side.

[0090] In a normal engine drive, power is transmitted from the input shaft 13 to the output shaft 15, so the belt gear ratio of the continuously variable transmission 20 is often set to the low gear side. However, when restarting the internal combustion engine 3, power is transmitted from the electric motor 4 to the internal combustion engine 3, so it is advantageous to set the belt gear ratio to the high gear side.

[0091] By setting the belt gear ratio to the high gear side, the output torque of the electric motor 4 required to rotate the internal combustion engine 3 can be reduced. This allows the internal combustion engine 3 to be restarted efficiently while suppressing the increase in output torque of the electric motor 4. As a result, the energy consumption of the electric motor 4 can be reduced, and the constraint of the upper limit of the output torque of the electric motor 4 can be avoided.

[0092] ≪Variations≫ Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and various modifications are possible.

[0093] For example, the above embodiment shows an example in which the torque capacity of the clutch device 50 is calculated based on hydraulic pressure, but the method for calculating torque capacity is not limited to this. For example, it is also possible to provide a sensor that detects the piston displacement of the clutch device 50 and calculate the torque capacity based on the value detected by this sensor.

[0094] Furthermore, various modifications are possible to the method for calculating the increase in output torque of the electric motor 4. For example, if the amount of inertia torque and friction loss torque generated differs depending on the type, displacement, and temperature conditions of the internal combustion engine 3, the torque increase can be adjusted by taking these conditions into consideration.

[0095] Furthermore, in this embodiment, an example was shown in which clutch torque capacity increase control, motor output torque increase control, and CVT belt gear ratio control are combined in the restart control of the internal combustion engine 3. However, it is also possible to apply only some of these controls. For example, it is possible to implement only clutch torque capacity increase control and motor output torque increase control, and omit the CVT belt gear ratio control.

[0096] Furthermore, although this embodiment describes the restart control of the internal combustion engine 3 when the output side is connected, the same control can be applied when restarting the internal combustion engine 3 when the input side is connected. In this case, the power of the electric motor 4 is transmitted to the internal combustion engine 3 via the electric motor connection shaft 60, the first driven shaft 30, the second driven shaft 35, the primary shaft 21, and the input shaft 13.

[0097] <Effects> The vehicle V described above has the following characteristic configurations (a) to (f). Therefore, the vehicle V of this embodiment can achieve the following unique effects that cannot be achieved with the prior art.

[0098] (a) The vehicle V of this embodiment is equipped with an internal combustion engine 3 and an electric motor 4, and is a vehicle that changes the driving mode by switching control of the drive source between the internal combustion engine 3 and the electric motor 4, and is equipped with an input shaft 13 that transmits power output from the internal combustion engine 3, an electric motor connection shaft 60 connected to the electric motor 4, an output shaft 15 that transmits power to the drive wheels of the vehicle V, a switching mechanism 70 that switches between an input-side connection state that enables power transmission between the electric motor connection shaft 60 and the input shaft 13 and an output-side connection state that enables power transmission between the electric motor connection shaft 60 and the output shaft 15, and a clutch 50 that transmits the rotation of the input shaft 13 to the output shaft 15, and is characterized in that when driving in the output-side connection state and restarting the internal combustion engine 3 in response to an internal combustion engine start request, the torque capacity of the clutch 50 is gradually increased and the output torque of the electric motor 4 is increased in conjunction with the increase in the torque capacity of the clutch 50.

[0099] As described in (a) above, the vehicle V of this embodiment is configured such that when restarting the internal combustion engine 3 in an output-side connected state that enables power transmission between the motor connecting shaft 60 and the output shaft 15, the torque capacity of the clutch 50 is gradually increased, and the output torque of the electric motor 4 is increased in conjunction with the increase in the torque capacity of the clutch 50. With this configuration, when restarting the internal combustion engine 3 in an output-side connected state, the shock when the clutch 50 engages can be prevented by gradually increasing the torque capacity of the clutch 50. In addition, by increasing the output torque of the electric motor 4 in conjunction with the increase in the torque capacity of the clutch 50, the loss of vehicle driving force due to inertia torque and friction loss torque that occurs when restarting the internal combustion engine 3 can be offset. Therefore, the vehicle V of this embodiment can suppress the loss of driving force and changes in acceleration that occur when restarting the internal combustion engine 3 in an output-side connected state, and the effect of improved drivability is obtained.

[0100] (b) In the vehicle V of this embodiment, the clutch 50 is characterized by being at least one of the forward clutch 51 and the reverse clutch 55.

[0101] As described in (b) above, the vehicle V of this embodiment is configured such that the clutch 50 is at least one of a forward clutch 51 and a reverse clutch 55. With this configuration, by controlling the forward clutch 51 or the reverse clutch 55, it is possible to prevent shocks when the internal combustion engine 3 is restarted while offsetting the loss of vehicle driving force. For example, the torque capacity of the forward clutch 51 can be controlled when driving forward, and the torque capacity of the reverse clutch 55 can be controlled when driving in reverse. Therefore, the vehicle V of this embodiment can suppress fluctuations in driving force when the internal combustion engine 3 is restarted, regardless of whether it is driving forward or in reverse.

[0102] Although the vehicle V in this embodiment is equipped with the configuration described in (b) above, the present invention is not limited thereto. The vehicle V may not be equipped with some or all of the configuration described in (b) above, or it may use, for example, a different type of clutch.

[0103] (c) In the vehicle V of this embodiment, the torque capacity of the clutch 50 is calculated based on the hydraulic pressure supplied to the clutch 50.

[0104] In this embodiment, the vehicle V is configured such that the torque capacity of the clutch 50 is calculated based on the hydraulic pressure supplied to the clutch 50, as described in (c) above. With this configuration, the torque capacity of the clutch 50 can be accurately determined by utilizing the correlation between the hydraulic pressure supplied to the clutch 50 and the torque capacity of the clutch 50. Therefore, in this embodiment, the vehicle V can appropriately control the increase in output torque of the electric motor 4 in conjunction with the increase in the torque capacity of the clutch 50, and can more effectively suppress fluctuations in driving force when the internal combustion engine 3 is restarted.

[0105] Although the vehicle V in this embodiment is equipped with the configuration described in (c) above, the present invention is not limited thereto. The vehicle V may not be equipped with some or all of the configuration described in (c) above, or the torque capacity of the clutch 50 may be calculated by other means. Other calculation methods include, for example, providing a sensor to detect the piston displacement of the clutch 50 and calculating the torque capacity based on the detected value of this sensor, or calculating it based on the temperature of the friction material of the clutch 50.

[0106] (d) In the vehicle V of this embodiment, the torque capacity of the clutch 50 is calculated based on the hydraulic pressure supplied to the clutch 50 detected by the hydraulic pressure sensor 115.

[0107] In this embodiment, the vehicle V is configured such that, as described in (d) above, the torque capacity of the clutch 50 is calculated based on the hydraulic pressure supplied to the clutch 50 as detected by the hydraulic pressure sensor 115. With this configuration, the torque capacity of the clutch 50 can be determined more accurately by directly detecting the hydraulic pressure actually supplied to the clutch 50 by the hydraulic pressure sensor 115. Therefore, in this embodiment, the accuracy of the output torque increase control of the electric motor 4, which is linked to the increase in the torque capacity of the clutch 50, is improved, and the effect of suppressing fluctuations in the driving force when the internal combustion engine 3 is restarted is obtained.

[0108] Although the vehicle V in this embodiment is equipped with the configuration described in (d) above, the present invention is not limited thereto. The vehicle V may not be equipped with some or all of the configuration described in (d) above, or it may be controlled without, for example, the hydraulic sensor 115. Even without the hydraulic sensor 115, the driving force fluctuations during the restart of the internal combustion engine 3 can be suppressed by using the target value of the torque capacity of the clutch 50. Furthermore, by not providing the hydraulic sensor 115, costs can be reduced and the configuration can be simplified.

[0109] (e) In the vehicle V of this embodiment, the torque capacity of the clutch 50 is calculated based on a target value for the torque capacity of the clutch 50.

[0110] As described in (e) above, the vehicle V of this embodiment is configured such that the torque capacity of the clutch 50 is calculated based on a target value for the torque capacity of the clutch 50. With this configuration, even if the hydraulic sensor 115 is not provided or if there is a response delay in the sensor value, the torque capacity of the clutch 50 can be appropriately estimated by using the target value for the torque capacity of the clutch 50. Therefore, the vehicle V of this embodiment can suppress fluctuations in the driving force when the internal combustion engine 3 is restarted, regardless of whether the sensor is present or not. Furthermore, by using both the detected value of the hydraulic sensor 115 and the target value, it is possible to estimate the torque capacity with higher accuracy, and the reliability of the control is also improved.

[0111] Although the vehicle V in this embodiment is equipped with the configuration described in (e) above, the present invention is not limited thereto. The vehicle V may not be equipped with some or all of the configuration described in (e) above, or it may be controlled based solely on the measured torque capacity of the clutch 50, for example. When using only the measured torque capacity of the clutch 50, more accurate control may be possible if the sensor has high responsiveness.

[0112] (f) In the vehicle V of this embodiment, when the internal combustion engine 3 is restarted, control is also performed to change the belt shift ratio of the continuously variable transmission 20 to the high gear side.

[0113] As described in (f) above, the vehicle V of this embodiment is configured to also implement control to shift the belt gear ratio of the continuously variable transmission 20 to the high gear side when restarting the internal combustion engine 3. This configuration allows for more efficient power transmission from the electric motor 4 to the internal combustion engine 3. In the output-side connection state, the power of the electric motor 4 is transmitted from the output shaft 15 to the input shaft 13, so it is advantageous to set the belt gear ratio to the high gear side. Therefore, the vehicle V of this embodiment can reduce the output torque of the electric motor 4 required to rotate the internal combustion engine 3, and can efficiently restart the internal combustion engine 3 while suppressing the increase in the output torque of the electric motor 4. As a result, it is possible to reduce the energy consumption of the electric motor 4 and avoid the constraint of the upper limit of the output torque of the electric motor 4.

[0114] Although the vehicle V in this embodiment is equipped with the configuration described in (f) above, the present invention is not limited thereto. The vehicle V may not be equipped with some or all of the configuration described in (f) above, or it may be possible to control the continuously variable transmission 20 while keeping the belt gear ratio fixed. When the belt gear ratio is kept fixed, the control of the continuously variable transmission 20 is simplified, and the responsiveness of the system may be improved. In addition, for example, if there is sufficient output torque from the electric motor 4, the control can be simplified by controlling without changing the belt gear ratio.

[0115] The configurations (a) to (f) described above can be combined in any way. In particular, by combining the configurations (c) to (e) concerning the method for calculating the torque capacity of the clutch 50 with the configuration (f) concerning the belt gear ratio control of the continuously variable transmission 20, it is possible to more effectively suppress fluctuations in the driving force when the internal combustion engine 3 is restarted while reducing the energy consumption of the electric motor 4.

[0116] The present invention is not limited to the configurations described in the embodiments, etc. above, and can be modified as appropriate without departing from the scope of the technical idea of ​​the present invention. The components of each embodiment and modified example described above can be arbitrarily selected and combined. Furthermore, any component of each embodiment and modified example can be arbitrarily combined with any component described in the means for solving the problem, the form for carrying out the invention, etc., or any component that embodies any component described in the means for solving the problem, the form for carrying out the invention, etc. The present application or a divisional application, amendment application, etc. based thereon also intends to obtain rights for these as well. [Industrial applicability]

[0117] The present invention can be suitably used in all types of vehicles that include an internal combustion engine, an electric motor, and a battery, and that change the driving mode by switching and controlling the drive source between the internal combustion engine and the electric motor. [Explanation of symbols]

[0118] 3: Internal combustion engine 4:Electric motor 13: Input axis 15: Output shaft 20: Continuously Variable Transmission 50: Clutch 51: Forward clutch 55: Reverse clutch 60: Motor connecting shaft 70: Switching mechanism 115: Hydraulic sensor V: Vehicle

Claims

1. A vehicle equipped with an internal combustion engine and an electric motor, which changes the driving mode by switching and controlling the drive source between the internal combustion engine and the electric motor, An input shaft that transmits power output from the internal combustion engine, The motor connection shaft connected to the aforementioned motor, An output shaft that transmits power to the drive wheels of the aforementioned vehicle, A switching mechanism that switches between an input-side connection state that enables power transmission between the motor connection shaft and the input shaft and an output-side connection state that enables power transmission between the motor connection shaft and the output shaft, A clutch that transmits the rotation of the input shaft to the output shaft, Equipped with, While driving with the output side connected, when restarting the internal combustion engine in response to a request to start the internal combustion engine, The torque capacity of the clutch is gradually increased, A vehicle characterized by increasing the output torque of the electric motor in conjunction with an increase in the torque capacity of the clutch.

2. The vehicle according to claim 1, characterized in that the clutch is at least one of a forward clutch and a reverse clutch.

3. The vehicle according to claim 1 or 2, characterized in that the torque capacity of the clutch is calculated based on the hydraulic pressure supplied to the clutch.

4. The vehicle according to claim 3, characterized in that the torque capacity of the clutch is calculated based on the hydraulic pressure supplied to the clutch detected by a hydraulic sensor.

5. The vehicle according to claim 3, characterized in that the torque capacity of the clutch is calculated based on a target value for the torque capacity of the clutch.

6. The vehicle according to claim 1 or 2, characterized in that when restarting the internal combustion engine, control is also performed to shift the belt gear ratio of the continuously variable transmission to the high gear side.

Images