vehicle

Abstract

In a vehicle that changes the driving mode by switching control between a drive source consisting of an internal combustion engine and an electric motor, the time lag during engine startup is suppressed. [Solution] The vehicle V includes an input shaft 13 that transmits power output from an internal combustion engine 3, an electric motor connection shaft 60 connected to an electric motor 4, a switching shaft that transmits power between the input shaft 13 and the electric motor connection shaft 60, an output shaft 15, a first switching mechanism that transmits and releases power between the input shaft 13 and the output shaft 15, a second switching mechanism that transmits and releases power between the electric motor connection shaft 60 and the output shaft 15, and a clutch device 50 for switching the power transmission state. A lock-up mechanism 12C is provided between the internal combustion engine 3 and the transmission 10. When the internal combustion engine 3 is stopped, the vehicle V engages the lock-up mechanism 12C and maintains the engaged state of the lock-up mechanism 12C while the internal combustion engine 3 is stopped.

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 travel 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 (for example, Patent Document 1). In such hybrid vehicles, one or both of the electric motor and the internal combustion engine are used as drive sources. Further, the electric motor in a hybrid vehicle is configured to exhibit a function as a generator that generates electric power by regenerative torque during vehicle braking.

[0003] In conventional CVT control, during low-speed travel or when the engine is stopped, the lock-up clutch is released so as not to hinder engine stall or engine start. However, in hybrid vehicles, the frequency of engine stop and engine restart during travel increases. Therefore, if the release control of the lock-up clutch is adopted, engagement of the lock-up clutch is required every time the engine is started, which leads to a problem of worsening of the time lag at the time of restart.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of Invention

Problems to be Solved by the Invention

[0005] Accordingly, an object of the present invention is to suppress the time lag at the time of engine start in a vehicle that changes a travel mode by performing switching control of a drive source including an internal combustion engine and an electric motor.

Means for Solving the Problems

[0006] (1) The present invention 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, wherein the vehicle has a transmission, which comprises an input shaft for transmitting power output from the internal combustion engine, an electric motor connection shaft connected to the electric motor, a switching shaft for transmitting power between the input shaft and the electric motor connection shaft, an output shaft for transmitting power to the drive wheels of the vehicle, a first switching mechanism for transmitting and releasing power between the input shaft and the output shaft, and a second switching mechanism for transmitting and releasing power between the electric motor connection shaft and the output shaft, wherein a lock-up mechanism is provided between the internal combustion engine and the transmission, and the lock-up mechanism is engaged when the internal combustion engine is stopped, and the engaged state of the lock-up mechanism is maintained while the internal combustion engine is stopped.

[0007] As described in (1) above, the vehicle of the present invention engages the lock-up mechanism when the internal combustion engine stops and maintains the engaged state of the lock-up mechanism while the internal combustion engine is stopped, eliminating the need to engage the lock-up mechanism when restarting the internal combustion engine. This shortens the time lag when restarting the internal combustion engine. Specifically, it can significantly reduce the time lag when restarting compared to conventional technology, and can greatly suppress the restart time. Furthermore, by equipping the powertrain with a transmission that switches between the internal combustion engine and the electric motor as the drive source, efficient power control according to various driving modes becomes possible.

[0008] (2) In the vehicle of the present invention described above, when the internal combustion engine is stopped, the lock-up mechanism is engaged and the clutch device constituting the first switching mechanism is released.

[0009] As described in (2) above, the vehicle of the present invention engages the lock-up mechanism and disengages the clutch device when the internal combustion engine stops, thereby interrupting power transmission from the internal combustion engine to the drive wheels. This prevents energy loss due to the rotation of the internal combustion engine. Furthermore, by disengaging the clutch device, it is possible to prevent the occurrence of unintended shocks, engine stalls, and other malfunctions when the internal combustion engine stops.

[0010] (3) In the vehicle of the present invention described above, the restart of the internal combustion engine may be performed by power transmission from the motor connecting shaft to the input shaft, or by power transmission from the output shaft to the input shaft.

[0011] As described in (3) above, the vehicle of the present invention can achieve a flexible restart method by restarting the internal combustion engine by transmitting power from the motor connection shaft to the input shaft, or by transmitting power from the output shaft to the input shaft. When restarting by transmitting power from the motor connection shaft, the torque of the motor can be directly transmitted to the internal combustion engine, so a restart with high responsiveness can be achieved. On the other hand, when restarting by transmitting power from the output shaft, the vehicle's driving energy can be utilized, so energy efficiency can be improved. In this way, the optimal restart method can be selected depending on the situation.

[0012] (4) The vehicle of the present invention described above may include the condition that the lock-up mechanism is engaged as a condition for stopping the internal combustion engine while it is running.

[0013] As described in (4) above, the vehicle of the present invention includes the condition that the lock-up mechanism is engaged as a stopping condition for the internal combustion engine while driving, thereby reducing the number of times the lock-up mechanism is engaged and disengaged each time the internal combustion engine is stopped and restarted. This simplifies the control logic, improves the reliability of the control system, and reduces development costs. Furthermore, by making the engaged state of the lock-up mechanism a stopping condition, it becomes possible to start the internal combustion engine in an optimal state when restarting, further reducing the time lag during restart.

[0014] (5) In the vehicle of the present invention described above, the first switching mechanism is a clutch and the second switching mechanism is a dog clutch.

[0015] As described in (5) above, the vehicle of the present invention can achieve optimal power transmission control according to the characteristics of each switching mechanism by using a clutch as the first switching mechanism and a dog clutch as the second switching mechanism. Since a clutch is a transmission mechanism that allows slippage, it enables smooth power transmission between the input shaft and the output shaft. In particular, a rotational difference is likely to occur between the input shaft and the output shaft, and a shock may occur due to sudden engagement, so a clutch that can control slippage is suitable for the first switching mechanism. On the other hand, since a dog clutch is a transmission mechanism that engages mechanically, it enables reliable power transmission between the motor connection shaft and the output shaft. This makes it possible to achieve efficient power transmission that corresponds to various operating modes, such as starting an internal combustion engine with an electric motor or driving a vehicle with an electric motor.

[0016] The above configurations (1) to (5) can be combined in any way. In particular, the combination of (1) and (2) allows for both a reduction in the time lag when restarting the internal combustion engine and prevention of energy loss due to the rotation of the internal combustion engine, thereby achieving both excellent fuel efficiency and driving performance. [Effects of the Invention]

[0017] According to the present invention, in a vehicle that changes the driving mode by switching control of a drive source consisting of an internal combustion engine and an electric motor, it is possible to suppress the time lag when starting the engine. [Brief explanation of the drawing]

[0018] [Figure 1] This is an overall front view of a vehicle according to one embodiment of the present invention, with the transmission cover cut out. [Figure 2] This is a skeleton diagram of one embodiment of the transmission shown in Figure 1. [Figure 3]This is a timing chart of internal combustion engine stop control during vehicle stopping. [Figure 4] This is a timing chart of internal combustion engine stop control during traveling. [Figure 5] This is a timing chart of internal combustion engine restart control from a stopped state. [Figure 6] This is a timing chart of internal combustion engine restart control during traveling. [Mode for Carrying Out the Invention]

[0019] Hereinafter, a vehicle V according to an embodiment of the present invention and a transmission 10 mounted thereon will be described in detail with reference to the drawings. It should be noted that each drawing is schematically represented for ease of understanding, and may differ from the actual shape, size, and arrangement of component parts. It should also be noted that the fact that each shaft is supported by an appropriate bearing or the like and is rotatable may be omitted. Further, in the following description, the front side of the vehicle V may be referred to as front Fr, and the rear side may be referred to as rear Rr.

[0020] «Basic Configuration of Transmission» As shown in FIG. 1 and FIG. 2, the vehicle V includes an internal combustion engine 3, an electric motor 4, and a battery 6, and switches and controls the drive source between the internal combustion engine 3 and the electric motor 4 to change the traveling mode. The vehicle V is provided with a transmission 10. Further, the internal combustion engine 3 and the electric motor 4 are connected to the transmission 10.

[0021] The internal combustion engine 3 is constituted by, for example, an engine such as a gasoline engine or a diesel engine. The internal combustion engine 3 has a drive shaft (not shown) connected to the input shaft 13 in the transmission 10. Therefore, the power output by the internal combustion engine 3 is input to the transmission 10 through the input shaft 13.

[0022] 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 (see Figure 5) 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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).

[0032] 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).

[0033] 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.

[0034] 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).

[0035] 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.

[0036] 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).

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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. 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.

[0041] 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.

[0042] 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.

[0043] The first driven gear 32 comprises a third driven gear 32A and a fourth driven gear 32B positioned on the rear side (Rr) of the third driven gear 32A.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.)

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] Control Method Next, we will describe the control performed in the vehicle V of this embodiment when the internal combustion engine 3 is stopped (internal combustion engine stop control).

[0055] <<Overview of Internal Combustion Engine Stop Control>> In the vehicle V of this embodiment, control is performed to maintain the lock-up mechanism 12C in an engaged state when the internal combustion engine 3 is stopped and while it is stopped. This eliminates the need to engage the lock-up mechanism 12C when restarting the internal combustion engine 3, thereby shortening the time lag during restart.

[0056] When stopping the internal combustion engine 3 while driving, vehicle V maintains the lock-up mechanism 12C in an engaged state and controls the clutch device 50 (forward clutch 51 and reverse clutch 55) to a disengaged state. By disengaging the clutch device 50, power transmission between the internal combustion engine 3 and the drive wheels is interrupted, preventing energy loss due to the rotation of the internal combustion engine 3.

[0057] The internal combustion engine 3 is shut down considering various factors, such as the vehicle's driving condition, the driver's operation, and the battery's charge level. For example, the internal combustion engine 3 is shut down when conditions such as the vehicle speed being above a certain value, the acceleration request being small, and the battery 6 being sufficiently charged are met. By setting these conditions, the internal combustion engine 3 can be shut down at the optimal timing, maximizing the fuel efficiency improvement effect.

[0058] The following describes in detail the specific control procedures for the internal combustion engine 3 during shutdown, while stopped, and during restart.

[0059] Control during internal combustion engine shutdown In this embodiment, vehicle V controls the lock-up mechanism 12C to engage (lock-up on) when the internal combustion engine 3 is stopped. This eliminates the need to engage the lock-up mechanism 12C when restarting the internal combustion engine 3, thereby shortening the time lag during restart.

[0060] Furthermore, when the internal combustion engine 3 stops, vehicle V controls the forward clutch 51 and the reverse clutch 55 to a disengaged state. This interrupts the power transmission from the internal combustion engine 3 to the drive wheels via the clutch device 50, preventing unintended shocks, engine stalls, and other malfunctions.

[0061] As shown in Figure 3, when the vehicle V is stationary and the internal combustion engine 3 is to be stopped, upon receiving a stop command for the internal combustion engine 3, the forward clutch 51 is first released, and then the lock-up mechanism 12C is engaged (turned on). This control sequence ensures that the clutch device 50 is released before directly connecting the internal combustion engine 3 and the torque converter 12, thereby preventing malfunctions in the power transmission system while achieving the engaged state of the lock-up mechanism 12C.

[0062] Furthermore, as shown in Figure 4, when stopping the internal combustion engine 3 while driving, the vehicle V, upon receiving a command to stop the internal combustion engine 3, maintains the lock-up mechanism 12C in the engaged state (on) while gradually reducing the hydraulic pressure of the forward clutch 51 to release it. This allows the rotational speed of the internal combustion engine 3 to be smoothly reduced, enabling the internal combustion engine 3 to be stopped without causing discomfort to the occupants. In addition, since the engaged state of the lock-up mechanism 12C is maintained even when the internal combustion engine 3 is stopped, the vehicle is ready for restart.

[0063] Control during internal combustion engine shutdown Vehicle V maintains the lock-up mechanism 12C engaged while the internal combustion engine 3 is stopped. This eliminates the need to engage the lock-up mechanism 12C when restarting the internal combustion engine 3, thereby shortening the time lag during restart.

[0064] Vehicle V maintains the clutch device 50 (forward clutch 51 and reverse clutch 55) in a disengaged state while the internal combustion engine 3 is stopped. This allows for smooth driving using the electric motor 4 (EV driving), increasing opportunities for fuel-efficient driving. In addition, the disengaged state of the forward clutch 51 and reverse clutch 55 prevents energy loss due to the rotation of the internal combustion engine 3.

[0065] When the vehicle V is stationary and the internal combustion engine 3 is stopped, the forward clutch 51 is released and the lock-up mechanism 12C is engaged, thereby ensuring a power transmission path from the electric motor 4 to the internal combustion engine 3 (the power transmission path from the electric motor connection shaft 60 to the input shaft 13 in the input-side connected state). This state setting makes it possible to drive the internal combustion engine 3 with the electric motor 4, and maintains a state where the vehicle is ready to restart the internal combustion engine 3 from a stationary position.

[0066] Furthermore, in this state, vehicle V can also generate electricity by using the electric motor 4 to rotate the internal combustion engine 3. This allows the battery 6 to be charged as needed, even when vehicle V is stationary, and extends the EV driving range powered by the electric motor 4.

[0067] Control during internal combustion engine restart Vehicle V can restart the internal combustion engine 3 in the following two ways:

[0068] The first method is restarting by transmitting power from the electric motor 4 to the internal combustion engine 3. In this method, the vehicle V restarts the internal combustion engine 3 by transmitting power from the electric motor 4 to the internal combustion engine 3 when a power transmission path is formed from the electric motor connecting shaft 60 to the input shaft 13 (the "input side connection state" described above). Specifically, the vehicle V restarts the engine by driving the electric motor 4 and rotating the internal combustion engine 3 via the electric motor connecting shaft 60, the first driven shaft 30, the second driven shaft 35, the primary shaft 21, and the input shaft 13. With this method, the vehicle V can directly transmit the torque of the electric motor 4 to the internal combustion engine 3, enabling restarting with high responsiveness.

[0069] The second method is restarting by transmitting power from the output shaft 15 to the internal combustion engine 3. In this method, the vehicle V is in a state where a power transmission path is formed from the output shaft 15 to the input shaft 13 (the "output side connection state" described above). When traveling forward, the engine is restarted by rotating the internal combustion engine 3 via the secondary pulley 27, belt 28, primary pulley 26, forward clutch 51, input shaft gear 14, and input shaft 13. When traveling in reverse, the engine is restarted by rotating the internal combustion engine 3 via the output shaft 15, secondary output gear 25, secondary input gear 24, reverse transmission mechanism 40, and input shaft 13. With this method, the vehicle V can effectively utilize deceleration energy to restart the internal combustion engine 3, thereby improving energy efficiency.

[0070] In this embodiment, since the lock-up mechanism 12C is already engaged while the internal combustion engine 3 is stopped, the electric motor 4 can be driven immediately when a restart command for the internal combustion engine 3 is issued. As a result, the vehicle V can shorten the time lag until the internal combustion engine 3 starts rotating and improve its responsiveness to the driver's acceleration requests.

[0071] As shown in Figure 5, when restarting the internal combustion engine 3 from a stationary state, the vehicle V maintains the engaged state of the lock-up mechanism 12C. This significantly reduces the time lag during restart compared to the conventional method, and greatly improves the responsiveness to the driver's acceleration requests.

[0072] As shown in Figure 6, even when the vehicle V restarts the internal combustion engine 3 while driving, it can immediately rotate the internal combustion engine 3 by maintaining the engaged state of the lock-up mechanism 12C and engaging the forward clutch 51. This allows for a quick response to acceleration requests while driving, resulting in improved drivability.

[0073] In this embodiment, control is performed using the control method described above. This makes it possible to achieve the specific effects described below.

[0074] Specifically, by engaging the lock-up mechanism 12C when the internal combustion engine 3 is stopped, and maintaining the engaged state of the lock-up mechanism 12C while the internal combustion engine 3 is stopped, the time lag when restarting the internal combustion engine 3 can be shortened.

[0075] Furthermore, by disengaging the clutch device 50 when the internal combustion engine 3 is stopped, the above effects can be obtained without causing energy loss due to the internal combustion engine 3 rotating along with the other components. With the clutch device 50 disengaged, power transmission from the internal combustion engine 3 to the drive wheels is interrupted, preventing energy loss due to the internal combustion engine 3 rotating along with the other components.

[0076] Furthermore, it becomes possible to engage the lock-up mechanism 12C regardless of vehicle speed, enabling a reduction in time lag with a simpler control specification. Conventionally, control was performed to release the lock-up mechanism 12C during low-speed driving, but according to the control method of this embodiment, the lock-up mechanism 12C can be kept engaged even during low-speed driving. This enables consistent control regardless of driving conditions and simplifies the control logic.

[0077] In addition, by engaging the lock-up mechanism 12C while the internal combustion engine 3 is stopped, a power transmission path from the electric motor 4 to the internal combustion engine 3 is secured. This allows the torque of the electric motor 4 to be directly transmitted to the internal combustion engine 3 when it is restarted, enabling a highly responsive restart. This improves responsiveness to the driver's acceleration requests and enhances drivability.

[0078] These effects make it possible to improve driving performance while maintaining fuel efficiency in a vehicle V equipped with an internal combustion engine 3 and an electric motor 4. This effect is particularly noticeable in city driving where the internal combustion engine 3 is frequently stopped and restarted.

[0079] ≪Variations≫ The embodiments described above are examples of the present invention, and various modifications are possible within the scope of the present invention.

[0080] For example, in this embodiment, the lock-up mechanism 12C is always engaged when the internal combustion engine 3 is stopped, but depending on the driving conditions of the vehicle V, control can also be performed to release the lock-up mechanism 12C. Under certain driving conditions, releasing the lock-up mechanism 12C may help suppress vibrations of the vehicle V and improve quietness.

[0081] Furthermore, in this embodiment, the forward clutch 51 and reverse clutch 55 are released when the internal combustion engine 3 stops. However, the release timing of the clutch device 50 can also be adjusted according to the vehicle's driving condition and the driver's operation. For example, if a sudden acceleration request is anticipated, the release of the clutch device 50 can be delayed to prepare for a quick restart.

[0082] Furthermore, in this embodiment, we have described a control that engages the lock-up mechanism 12C while the internal combustion engine 3 is stopped to shorten the time lag when restarting the internal combustion engine 3. However, it is also possible to combine this control with other controls. For example, by combining it with a control to improve the starting performance of the internal combustion engine 3 or a control to optimize the torque characteristics of the electric motor 4, it is possible to further shorten the restart time and improve fuel efficiency.

[0083] In addition, in this embodiment, two methods for restarting the internal combustion engine 3 were described: restarting by transmitting power from the electric motor 4 to the internal combustion engine 3, and restarting by transmitting power from the output shaft 15 to the internal combustion engine 3. However, it is also possible to control the system to select the optimal restart method according to the state of the vehicle V. For example, if the charge level of the battery 6 is low, restarting by transmitting power from the output shaft 15 can be prioritized to reduce the consumption of the battery 6.

[0084] As described above, the present invention can be realized in various embodiments, and in each embodiment, it is possible to perform optimal control according to the situation.

[0085] ≪Specific configuration and effects of vehicle V≫ The vehicle V according to this embodiment described above has characteristic configurations such as (a) to (e) below. Because it has such configurations, the vehicle V can achieve the following unique effects.

[0086] (a) The vehicle V of this embodiment is equipped with an internal combustion engine 3 and an electric motor 4, and changes the driving mode by switching control of the drive sources of the internal combustion engine 3 and the electric motor 4. The vehicle V has a transmission 10, which includes 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, a switching shaft that transmits power between the input shaft 13 and the electric motor connection shaft 60, an output shaft 15 that transmits power to the drive wheels of the vehicle V, a first switching mechanism that transmits and releases power between the input shaft 13 and the output shaft 15, and a second switching mechanism that transmits and releases power between the electric motor connection shaft 60 and the output shaft 15. A lock-up mechanism 12C is provided between the internal combustion engine 3 and the transmission 10, and the lock-up mechanism 12C is engaged when the internal combustion engine 3 stops, and the engaged state of the lock-up mechanism 12C is maintained while the internal combustion engine 3 is stopped.

[0087] In this embodiment, as described in (a) above, the vehicle V engages the lock-up mechanism 12C when the internal combustion engine 3 stops, and maintains the engaged state of the lock-up mechanism 12C while the internal combustion engine 3 is stopped, eliminating the need to engage the lock-up mechanism 12C when restarting the internal combustion engine 3. This shortens the time lag when restarting the internal combustion engine 3. Specifically, the time lag when restarting can be reduced by approximately 1 second compared to the conventional technology, and the restart time can be reduced by approximately half. Furthermore, by providing a transmission 10 that switches between the drive sources of the internal combustion engine 3 and the electric motor 4 as part of the powertrain configuration, efficient power control according to various driving modes becomes possible.

[0088] (b) In this embodiment, when the internal combustion engine 3 of the vehicle V is stopped, the lock-up mechanism 12C is engaged and the clutch device 50 constituting the first changeover is released.

[0089] In this embodiment, as described in (b) above, when the internal combustion engine 3 stops, the vehicle V engages the lock-up mechanism 12C and disengages the clutch device 50, thereby interrupting power transmission from the internal combustion engine 3 to the drive wheels. This prevents energy loss due to the internal combustion engine 3 rotating with the vehicle. Furthermore, by disengaging the clutch device 50, it is possible to prevent unintended shocks, engine stalls, and other malfunctions when the internal combustion engine 3 stops.

[0090] (c) In this embodiment, the restart of the internal combustion engine 3 of the vehicle V is performed by power transmission from the motor connecting shaft 60 to the input shaft 13, or by power transmission from the output shaft 15 to the input shaft 13.

[0091] As described in (c) above, the vehicle V of this embodiment can achieve a flexible restart method by restarting the internal combustion engine 3 by transmitting power from the motor connecting shaft 60 to the input shaft 13, or by transmitting power from the output shaft 15 to the input shaft 13. When restarting by transmitting power from the motor connecting shaft 60, the torque of the electric motor 4 can be directly transmitted to the internal combustion engine 3, so a restart with high responsiveness can be achieved. On the other hand, when restarting by transmitting power from the output shaft 15, the driving energy of the vehicle V can be utilized, so energy efficiency can be improved. In this way, the optimal restart method can be selected depending on the situation.

[0092] (d) The vehicle V of this embodiment includes a condition for stopping the internal combustion engine 3 while it is in motion, in which case the lock-up mechanism 12C is engaged.

[0093] As described in (d) above, the vehicle V of this embodiment includes the lock-up mechanism 12C being engaged as a stopping condition for the internal combustion engine 3 while driving, thereby reducing the number of times the lock-up mechanism 12C is engaged and disengaged each time the internal combustion engine 3 is stopped and restarted. This simplifies the control logic, improves the reliability of the control system, and reduces development costs. Furthermore, by making the lock-up mechanism 12C being engaged a stopping condition, it becomes possible to start the internal combustion engine 3 in an optimal state when restarting, further reducing the time lag during restart.

[0094] (e) In this embodiment, the vehicle V has a first switching mechanism which is a clutch and a second switching mechanism which is a dog clutch.

[0095] As described in (e) above, the vehicle V of this embodiment can achieve optimal power transmission control according to the characteristics of each switching mechanism by using a clutch as the first switching mechanism and a dog clutch as the second switching mechanism. Since a clutch is a transmission mechanism that allows slippage, it enables smooth power transmission between the input shaft 13 and the output shaft 15. In particular, a rotational difference is likely to occur between the input shaft 13 and the output shaft 15, and a shock may occur due to sudden engagement, so a clutch that can control slippage is suitable for the first switching mechanism. On the other hand, since a dog clutch is a transmission mechanism that engages mechanically, it enables reliable power transmission between the motor connection shaft 60 and the output shaft 15. This makes it possible to achieve efficient power transmission that corresponds to various operating modes, such as starting the internal combustion engine 3 by the electric motor 4 and driving the vehicle V by the electric motor 4.

[0096] The configurations (a) to (e) above can be combined in any way. In particular, the combination of (a) and (b) allows for both a reduction in the time lag when restarting the internal combustion engine 3 and prevention of energy loss due to the rotation of the internal combustion engine 3, thereby achieving both excellent fuel efficiency and driving performance.

[0097] 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 modification described above can be arbitrarily selected and combined. Furthermore, any component of each embodiment and modification can be arbitrarily combined with any component described in the means for solving the problem, the form for carrying out the invention, etc., or a component that embodies any component described in the means for solving the problem, the form for carrying out the invention, etc. The present application also intends to obtain rights in this application or in divisional applications, amendment applications, etc. based on this application. [Industrial applicability]

[0098] 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]

[0099] 3: Internal combustion engine 4: Electric motor 10: Transmission 12C: Lock-up mechanism 13: Input axis 15: Output axis 50: Clutch device 60: Motor connecting shaft 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 sources of the internal combustion engine and the electric motor, The aforementioned vehicle has a transmission, The aforementioned transmission is, An input shaft that transmits power output from the internal combustion engine, The motor connection shaft connected to the aforementioned motor, A switching shaft that transmits power between the input shaft and the motor connection shaft, An output shaft that transmits power to the drive wheels of the aforementioned vehicle, A first switching mechanism for transmitting and releasing power between the input shaft and the output shaft, A second switching mechanism for transmitting and releasing power between the motor connection shaft and the output shaft, Equipped with, A lock-up mechanism is provided between the internal combustion engine and the transmission. When the internal combustion engine is stopped, the lock-up mechanism is engaged. A vehicle characterized by maintaining the engaged state of the lock-up mechanism while the internal combustion engine is stopped.

2. The vehicle according to claim 1, characterized in that when the internal combustion engine is stopped, the lock-up mechanism is engaged and the clutch device constituting the first switching mechanism is released.

3. The vehicle according to claim 1 or 2, characterized in that the restart of the internal combustion engine is performed by power transmission from the motor connecting shaft to the input shaft, or by power transmission from the output shaft to the input shaft.

4. The vehicle according to claim 1 or 2, characterized in that the conditions for stopping the internal combustion engine while driving include the lock-up mechanism being engaged.

5. The vehicle according to claim 1 or 2, characterized in that the first switching mechanism is a clutch and the second switching mechanism is a dog clutch.

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