Clutch control device

Abstract

To provide a clutch control device that controls the clutch standby position to an optimal position according to the situation, thereby suppressing clutch drag and improving clutch durability, as well as preventing the time required for clutch engagement during gear changes and starting from becoming excessively long. [Solution] A clutch control device for use in a vehicle comprising an engine, a transmission mechanism that changes the engine's rotation speed at a gear ratio corresponding to the gear shift and outputs the result, a clutch that can be switched between an engaged state that transmits power between the engine and the transmission mechanism, and a disengaged state that disconnects the transmission of power, and a clutch actuator that automatically operates the clutch, the control device having a control unit that changes the clutch standby position, which is the stroke position of the clutch in the disengaged state during gear shifting, according to the engine's operating state.

Description

Technical Field

[0001] The present invention relates to a clutch control device.

Background Art

[0002] Patent Document 1 discloses a transmission control device that learns, as a power transmission start point of the friction clutch, the clutch stroke of the friction clutch when the rotational speed difference between the output shaft of the engine and the input shaft of the transmission is equal to or greater than a predetermined rotational speed difference when the friction clutch is changed from an engaged state toward a released state.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of Invention

Problems to be Solved by the Invention

[0004] By the way, for example, in order to quickly engage the clutch and start torque transmission at an early stage when the vehicle starts or shifts gears, the stroke time from the stroke position when the clutch is in a released state (hereinafter referred to as "clutch standby position") to the power transmission start point is wasted time, so the clutch standby position is preferably set near the power transmission start point.

[0005] However, at the clutch standby position set near the power transmission start point, even at the clutch standby position where the clutch should be in a released state, in a situation where the engine vibrates, the flywheel or clutch cover swings, causing the clutch disc to abut against the pressure plate or the flywheel, and there is a risk that torque is intermittently transmitted (this is also referred to as "clutch drag").

[0006] If clutch drag occurs during gear shifting, as described above, it negatively affects the adjustment of the rotational speed of the clutch disc, which is the input rotational element of the transmission (hereinafter referred to as "clutch rotational speed"). This increases the time it takes for the clutch rotational speed to synchronize with the rotational speed of the target gear, resulting in a longer gear shift time.

[0007] In contrast, if the clutch standby position is moved away from the power transmission start point, the clutch drag described above becomes less likely to occur.

[0008] However, if the clutch standby position is moved away from the power transmission start point, even in engine conditions where clutch drag does not occur, the distance from the clutch standby position to the power transmission start point increases, which lengthens the time it takes to initiate clutch engagement. As a result, the time required for clutch engagement, such as for shifting gears or starting, becomes longer even in unnecessary situations. For example, a delay in clutch engagement when starting a vehicle results in poor responsiveness to accelerator input, which reduces the vehicle's marketability.

[0009] The present invention has been made in view of the circumstances described above, and aims to provide a clutch control device that can control the clutch standby position to an optimal position according to the situation, thereby suppressing clutch drag and improving the durability of the clutch, as well as preventing the time required for clutch engagement, such as for shifting gears or starting, from becoming excessively long. [Means for solving the problem]

[0010] To achieve the above objective, the present invention provides a clutch control device for use in a vehicle comprising: an engine; a transmission mechanism that changes the rotation of the engine at a gear ratio corresponding to the gear shift and outputs the result; a clutch that can be switched between an engaged state for transmitting power between the engine and the transmission mechanism, and a released state for interrupting the transmission of power; and a clutch actuator that automatically operates the clutch, wherein the control device has a control unit that changes the clutch standby position, which is the stroke position of the clutch in the released state during gear shifting, according to the operating state of the engine. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a clutch control device that can control the clutch standby position to an optimal position according to the situation, thereby suppressing clutch drag and improving the durability of the clutch, as well as preventing the time required for clutch engagement, such as for shifting gears or starting, from becoming excessively long. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a schematic diagram of a vehicle equipped with a clutch control device according to one embodiment of the present invention. [Figure 2] Figure 2 is a block diagram of a control device for a vehicle equipped with a clutch control device according to one embodiment of the present invention. [Figure 3] Figure 3 illustrates the difference in synchronization time due to differences in the clutch standby position, where (a) shows a configuration in which the clutch standby position is close to the power transmission start point, and (b) shows a configuration in which the clutch standby position is far from the power transmission start point. [Figure 4] Figure 4 shows a timing chart for upshifting in a vehicle equipped with a clutch control device according to one embodiment of the present invention, where (a) shows the case when the engine speed is high and (b) shows the case when the engine speed is low. [Figure 5]Figure 5 shows a timing chart for downshifting in a vehicle equipped with a clutch control device according to one embodiment of the present invention, where (a) shows the case where the accelerator opening is large and the engine load is high, and (b) shows the case where the accelerator opening is small and the engine load is low. [Figure 6] Figure 6 is a timing chart illustrating the effect of changing the clutch standby position to a position further away from the power transmission start point. [Figure 7] Figure 7 is a timing chart illustrating the change in clutch engagement speed in a vehicle equipped with a clutch control device according to one embodiment of the present invention. [Figure 8] Figure 8 is a flowchart showing the control flow during gear shifting in a vehicle equipped with a clutch control device according to one embodiment of the present invention. [Modes for carrying out the invention]

[0013] A clutch control device according to one embodiment of the present invention is a clutch control device used in a vehicle comprising an engine, a transmission mechanism that changes the rotation of the engine at a gear ratio corresponding to the gear shift and outputs the result, a clutch that can be switched between an engaged state that transmits power between the engine and the transmission mechanism, and a disengaged state that interrupts the transmission of power, and a clutch actuator that automatically operates the clutch, and has a control unit that changes the clutch standby position, which is the stroke position of the clutch in the disengaged state during gear shifting, according to the operating state of the engine. As a result, the clutch control device according to one embodiment of the present invention can control the clutch standby position to an optimal position according to the situation and prevent the gear shifting time from becoming long. [Examples]

[0014] A vehicle equipped with a clutch control device according to one embodiment of the present invention will be described below with reference to Figures 1 to 8.

[0015] As shown in Figure 1, the vehicle 1 is a hybrid vehicle configured to include an internal combustion engine type engine 2, a transmission 3, a motor generator (labeled as "MG" in Figure 1) 4 serving as a motor, and drive wheels 5. The engine 2 and the motor generator 4 function as power sources that generate power (torque) for propelling the vehicle 1.

[0016] The engine 2 is formed with a plurality of cylinders. In the present embodiment, the engine 2 is configured to perform a series of four strokes including an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke for each cylinder. The engine 2 is configured to be able to transmit power to the drive wheels 5 via a clutch 32 described later.

[0017] An ISG (Integrated Starter Generator) 20 and a starter (labeled as "ST" in Figure 1) 21 are connected to the engine 2. The ISG 20 is connected to the crankshaft 18 of the engine 2 via a power transmission member such as a belt 22. The ISG 20 has a function of an electric motor that rotationally drives the engine 2 by being supplied with electric power to rotate, and a function of a generator that converts rotational force input from the crankshaft 18 into electric power.

[0018] In the present embodiment, the ISG 20 functions as an electric motor to restart the engine 2 from a stopped state by the idling stop function. The ISG 20 can also function as a power source that assists the traveling of the vehicle 1 via the engine 2 by functioning as an electric motor.

[0019] The starter 21 is configured to include a motor (not shown) and a pinion gear. The starter 21 is configured to rotate the crankshaft 18 by rotating the motor to apply rotational force at the time of start-up to the engine 2. In this way, the engine 2 is started by the starter 21, and is restarted by the ISG 20 from the stopped state by the idling stop function.

[0020] The transmission 3 changes the speed of the rotation output from the engine 2 and transmits it to the drive wheels 5 via the drive shaft 23, thereby driving the drive wheels 5. The transmission 3 includes a normally meshing type gear shifting mechanism 31 consisting of a parallel shaft gear mechanism, a clutch 32 consisting of a normally closed type dry single-plate clutch, a clutch actuator 35 (see Figure 2), and a shift actuator 36.

[0021] The transmission 3 is configured as a so-called AMT (Automated Manual Transmission), and the gear changes in the gear shifting mechanism 31 are performed by a shift actuator 36 (see Figure 2) controlled by a control device 10, which will be described later, and the clutch actuator 35 (see Figure 2) engages or disengages the clutch 32.

[0022] The transmission mechanism 31 has gear pairs (not shown) and a synchronization mechanism that constitute multiple gear stages, and outputs the rotation of the engine 2 at a gear ratio corresponding to the gear pairs that constitute the gear stages.

[0023] The clutch 32 is a friction clutch configured to switch between an engaged state, which transmits power between the engine 2 and the transmission mechanism 31, and a disengaged state, which disconnects the transmission of said power, by a clutch actuator 35 (see Figure 2), which will be described later.

[0024] Specifically, the clutch 32 includes a flywheel 32a connected to the crankshaft 18 and a clutch disc 32b connected to the input shaft 31a of the transmission mechanism 31 so as to rotate integrally with it. A clutch cover (not shown) is connected to the flywheel 32a, and a pressure plate (not shown) is connected to the clutch cover. The clutch disc 32b is positioned between the flywheel 32a and the pressure plate.

[0025] The clutch 32 can be switched between an engaged state in which the clutch disc 32b and the flywheel 32a rotate together to transmit power by pressing the clutch disc 32b against the flywheel 32a, and a released state in which the clutch disc 32b is separated from the flywheel 32a, interrupting power transmission between the flywheel 32a and the clutch disc 32b. Furthermore, a semi-clutch state, which is an intermediate state between the integrated engaged state and the separated released state, in which the clutch disc 32b rotates relative to the flywheel 32a while making frictional contact with it, can also be controlled.

[0026] The motor-generator 4 is connected to the output side of the transmission mechanism 31 via a power transmission mechanism 42 such as a chain. Therefore, there is no disengagement mechanism such as a clutch 32 between the motor-generator 4 and the drive wheel 5, and the motor-generator 4 is directly connected to the drive wheel 5 via the power transmission mechanism 42. As a result, the motor-generator 4 is configured to transmit power to the drive wheel 5 without going through the clutch 32.

[0027] The motor generator 4 is configured to output assist torque to the drive wheels 5 while the clutch 32 is disengaged during driving. This suppresses torque loss during gear changes.

[0028] The motor generator 4 functions not only as an electric motor but also as a generator, and can generate electricity through the movement of vehicle 1.

[0029] Thus, Vehicle 1 is a parallel hybrid system that can use the power of both the engine 2 and the motor generator 4 to drive the vehicle, and is a hybrid vehicle that runs on the power output of at least one of the engine 2 and the motor generator 4.

[0030] Vehicle 1 is equipped with a high-voltage battery (indicated as "HV BT" in Figure 1) 40 and a low-voltage battery (indicated as "Pb BT" in Figure 1) 50. The high-voltage battery 40 and the low-voltage battery 50 are each composed of rechargeable secondary batteries.

[0031] The high-voltage battery 40 is, for example, a lithium-ion battery and is electrically connected to the motor generator 4 via an inverter (indicated as "INV" in Figure 1) 41, and is configured to supply power to the motor generator 4.

[0032] The inverter 41 is configured to convert between AC power and DC power. For example, when the motor generator 4 is powered, the inverter 41 converts the DC power discharged by the high-voltage battery 40 into AC power and supplies it to the motor generator 4. Conversely, when the motor generator 4 performs regenerative power generation, the inverter 41 converts the AC power generated by the motor generator 4 into DC power and charges the high-voltage battery 40.

[0033] The low-voltage battery 50 is made of, for example, a lead-acid battery, is electrically connected to the ISG 20 and the starter 21, and is configured to supply power to the ISG 20 and the starter 21. The low-voltage battery 50 is also configured to supply power to electrical loads other than the ISG 20 and the starter 21.

[0034] As shown in Figure 2, vehicle 1 is equipped with a control device 10. The control device 10 consists of a computer unit that includes a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), flash memory for storing backup data, an input port, and an output port.

[0035] The ROM of these computer units stores, for example, various constants and maps, along with a program that allows the computer unit to function as a control device 10.

[0036] The control device 10 is connected to various sensors, including a crank angle sensor 11, a clutch rotation speed sensor 12, a vehicle speed sensor 13, an accelerator pedal position sensor 14, a clutch position detection sensor 15, and a shift position sensor 16.

[0037] The crank angle sensor 11 detects the rotation angle of the crankshaft 18 of the engine 2 (hereinafter referred to as "crank angle"). The control device 10 calculates the engine speed, which is the rotational speed of the engine 2, based on the information indicating the crank angle input from the crank angle sensor 11.

[0038] The clutch rotation speed sensor 12 detects the rotation speed of the clutch disc 32b and the input shaft 31a (hereinafter referred to as "clutch rotation speed"). The vehicle speed sensor 13 detects the vehicle speed, which is the speed of the vehicle 1.

[0039] The accelerator pedal position sensor 14 detects the amount of accelerator pedal depression by the driver (not shown). Alternatively, the accelerator pedal position sensor 14 may also detect the movement of the throttle valve, which changes in conjunction with the amount of accelerator pedal depression.

[0040] The clutch position detection sensor 15 detects the position of a release bearing (not shown) in the clutch 32, or the position of a release fork or other component that moves in relation to the movement state of the release bearing (hereinafter referred to as "clutch position"). The clutch position indicates the state of the clutch 32 (disengaged state / half-clutched state / engaged state), and can also be considered to indicate the magnitude of the torque transmitted by the clutch 32.

[0041] The shift position sensor 16 detects, for example, the gear position that is currently set in the transmission mechanism 31.

[0042] The control device 10 is connected to various devices such as a motor generator 4, a clutch actuator 35, and a shift actuator 36.

[0043] The clutch actuator 35 performs a clutch operation to switch the operating state of the clutch 32. Specifically, the clutch actuator 35 moves a release bearing (not shown) in the axial direction of the input shaft 31a using a release fork or the like, and elastically deforms the diaphragm spring of the flywheel 32a using the release bearing, thereby moving the pressure plate that was pressing the clutch disc 32b against the flywheel 32a away from the clutch disc 32b. As a result, the clutch 32 is released.

[0044] The clutch actuator 35 moves the release bearing from the released position in the opposite direction to when it is released, and releases the diaphragm spring from elastic deformation, thereby causing the pressure plate to press the clutch disc 32b against the flywheel 32a. This causes the clutch 32 to engage.

[0045] The shift actuator 36 performs the gear shifting operation in the transmission mechanism 31.

[0046] Various controllers, such as the engine ECU 37 and the battery management controller 38, are connected to the control device 10 in a bidirectional manner. The engine ECU 37 controls the operation of the engine 2 by controlling the ignition system and fuel injection system (not shown).

[0047] The battery management controller 38 manages the status of the high-voltage battery 40, such as its charge level. The battery management controller 38 monitors the charge level of the high-voltage battery 40 and transmits, for example, the current charge level to the control device 10.

[0048] The control device 10 is configured to switch the driving state (driving mode) of the vehicle 1. The driving states of the vehicle 1 include EV driving, E / G driving, and HEV driving.

[0049] EV driving is a driving state in which the engine 2 is stopped and the vehicle 1 is driven by the power of the motor generator 4 (hereinafter also referred to as motor torque). At this time, the clutch 32 is switched to a released state by the clutch actuator 35, which disconnects the transmission of power between the engine 2 and the transmission mechanism 31. During EV driving, the control device 10 controls the motor generator 4 so that the motor torque meets the torque requested by the driver.

[0050] Engine-driven driving is a driving state in which the vehicle 1 is driven by the power of engine 2 (hereinafter also referred to as engine torque) generated by engine 2. During engine-driven driving, the control device 10 controls engine 2 so that the engine torque satisfies the torque requested by the driver.

[0051] HEV driving is a driving state in which the engine 2 is operated, and the vehicle 1 is driven by the power of the engine 2 and the power of the motor generator 4. During HEV driving, the control device 10 controls the engine 2 and the motor generator 4 so that the total torque obtained by adding the engine torque and the motor torque satisfies the torque requested by the driver.

[0052] The control device 10 switches the driving mode to one of EV driving, E / G driving, or HEV driving depending on the state of the vehicle 1, for example, the charge state of the high-voltage battery 40 or the temperature state of the clutch 32.

[0053] The control device 10, for example, determines whether or not to perform a gear change based on a gear map in which the gear position is determined based on the vehicle speed and accelerator opening. If it decides to perform a gear change, it automatically performs clutch and shift operations to perform the gear change.

[0054] When shifting gears, the control device 10 controls the clutch actuator 35 and the shift actuator 36 to switch the clutch 32 from the engaged state to the disengaged state, then switch the gear in the shift mechanism 31, and then switch the clutch 32 back from the disengaged state to the engaged state, thereby automatically performing clutch and shift operations.

[0055] In order to suppress torque loss during gear changes, the control device 10 controls the motor generator 4 to output assist torque to the drive wheels 5 while the clutch 32 is disengaged during gear changes.

[0056] The control device 10 functions as a control unit 60 that changes the clutch standby position, which is the stroke position of the clutch 32 in the released state during gear shifting, according to the operating state of the engine 2. Here, gear shifting that changes the clutch standby position includes both upshift and downshift gear shifting.

[0057] Specifically, when the engine 2 is operating at high speed, the control device 10 changes the clutch standby position to a position further away from the power transmission start point of the clutch 32 compared to when the engine 2 is operating at low speed.

[0058] The high-speed state described above refers to the state in which the engine 2 is operated in a predetermined rotational speed range in which vibrations occur in the engine 2 that cause the flywheel 32a and the clutch cover (not shown) to wobble, resulting in clutch drag. The rotational speed range in which vibrations causing clutch drag occur in the engine 2 has been determined experimentally in advance.

[0059] When performing an upshift, the control device 10 can determine that the engine 2 is operating at a high speed if the engine speed at the time of transitioning to the gear shift phase, which will be described later, is within the predetermined rotational speed range described above.

[0060] When downshifting, the control device 10 estimates the engine speed after the shift is completed based on the target gear (the gear to which the shift is made) and the vehicle speed. If the estimated engine speed is within the predetermined rotation range described above, the control device 10 can determine that the engine 2 is operating at a high rotation speed.

[0061] The stroke position of the clutch 32 described above actually corresponds to the position of the release bearing moved axially by the clutch actuator 35 in the input shaft 31a. Therefore, the clutch standby position can also be said to be the position of the release bearing when the clutch 32 is in a disengaged state during gear shifting, that is, when the clutch disc 32b is not in contact with the flywheel 32a, or when it is in contact but no torque is being transmitted.

[0062] The power transmission start point mentioned above refers to the stroke position of the clutch 32, that is, the position of the release bearing, when the gap between the flywheel 32a and the pressure plate narrows, the clutch disc 32b begins to contact the flywheel 32a, and torque transmission begins.

[0063] Here, since no torque is transmitted by the clutch 32 between the power transmission start point and the clutch standby position, the time required to move the stroke position of the clutch 32 from the clutch standby position to the power transmission start point is wasted, for example, when the vehicle starts moving. For this reason, it is desirable for the clutch standby position to be as close as possible to the power transmission start point.

[0064] However, if the clutch standby position is close to the power transmission start point, there is a risk that the aforementioned clutch drag may occur due to vibrations of the engine 2 when the engine 2 is operating at high rotational speeds.

[0065] Therefore, in this embodiment, when the engine 2 is running at high RPMs where clutch drag may occur, the clutch standby position is changed to a position away from the power transmission start point of the clutch 32, as described above.

[0066] In this embodiment, an example was described in which the clutch standby position is changed to a position further away from the power transmission start point of the clutch 32 when the engine 2 is operating at high speed. However, the embodiment is not limited to this, and the clutch standby position may also be changed to a position further away from the power transmission start point of the clutch 32 when the engine 2 is operating under high load compared to when the engine 2 is operating under low load. In this case, the high load state of the engine 2 is a state in which the engine 2 is operated in a load region in which vibrations occur in the engine 2 that cause the flywheel 32a and a clutch cover (not shown) to wobble, resulting in clutch drag. The load region in which vibrations that cause clutch drag occur in the engine 2 have been determined experimentally in advance, for example, based on the accelerator opening that correlates with the load of the engine 2.

[0067] Furthermore, when the engine 2 is operating at high rotation speed and under high load, the clutch standby position may be changed to a position further away from the power transmission start point of the clutch 32.

[0068] Next, referring to Figure 3, we will explain the difference in synchronization time due to differences in clutch standby position.

[0069] Figures 3(a) and 3(b) both show the relationship between engine speed, clutch speed, and clutch stroke during gear changes (upshifts) when the engine speed is high. In Figure 3, the clutch stroke is expressed as a large value when engaged and a small value when disengaged. The clutch standby position (A) is a clutch stroke position close to the power transmission start point, and the clutch standby position (B) is a clutch stroke position further from the power transmission start point than the clutch standby position (A). Both the clutch standby position (A) and the clutch standby position (B) are clutch stroke positions where the clutch is disengaged. Torque transmission occurs in the clutch 32 at clutch stroke positions above the power transmission start point. The clutch standby position and the power transmission start point are determined by the clutch stroke.

[0070] As shown in Figure 3(a), when the clutch standby position during gear shifting is the clutch standby position (A) which is close to the power transmission start point, the clutch stroke decreases to the clutch stroke position that releases the clutch 32 at time t1. However, because the engine speed is high, which generates vibrations, the clutch disc 32b comes into contact with the pressure plate and flywheel 32a, causing clutch drag and preventing the clutch speed from decreasing quickly. As a result, the time it takes for the clutch speed to reach the speed of the gear after gear shifting (hereinafter also called the "synchronous speed") (hereinafter also called the "synchronous time") becomes longer. In other words, in upshifting, the clutch speed needs to decrease quickly to reach the speed of the next gear, but the slow engine speed hinders the decrease in speed, and the synchronous time until the clutch speed reaches the synchronous speed becomes longer.

[0071] In contrast, as shown in Figure 3(b), when the clutch standby position during gear shifting is clutch standby position (B), after the clutch 32 reaches the disengaged state at time t1, the clutch disc 32b is released to a clutch stroke position where it does not contact the pressure plate or flywheel 32a. As a result, clutch drag does not occur, the clutch rotation speed decreases rapidly, and the synchronization time is shorter compared to when the clutch standby position is clutch standby position (A).

[0072] Next, with reference to Figures 4 and 5, the clutch standby position during gear shifting, which is executed by the control device 10 according to this embodiment and corresponds to the engine operating state, will be described.

[0073] In Figures 4 and 5, the "clutch release phase" refers to the stage in which a clutch operation is performed to move the engaged clutch 32 towards the release state, the "gear shift phase" refers to the stage in which the clutch 32 is in the release state and a gear shift operation is performed in the transmission mechanism 31, and the "clutch engagement phase" refers to the stage in which a clutch operation is performed to move the released clutch 32 towards the engagement state.

[0074] Furthermore, in Figures 4 and 5, "target gear" refers to the gear corresponding to the planned (destined) gear shift, and "actual gear" refers to the gear corresponding to the actual gear shift. Therefore, when the actual gear matches the target gear, the gear shift in the transmission mechanism 31, that is, the gear shift, is completed.

[0075] (During upshift) Figures 4(a) and 4(b) are both timing charts for upshifting, showing the case where the accelerator is pressed by the driver and the engine speed is high (Figure 4(a)), and the case where, for example, the accelerator is not pressed and the engine speed is low (Figure 4(b)).

[0076] As shown in Figure 4(a), when the engine speed is high, the clutch standby position during gear shifting, i.e., the clutch standby position in the gear shift phase, is changed from the clutch standby position (A) to the clutch standby position (B), which is a clutch stroke position that further releases the clutch 32.

[0077] As a result, clutch drag does not occur during the gear shift phase, the clutch rotation speed decreases rapidly, and the synchronization time is shortened compared to when the clutch is in the clutch standby position (A).

[0078] In other words, in this embodiment, when the engine speed is high, the synchronization time is shorter compared to when the clutch standby position is not changed (for example, when the clutch standby position is kept at clutch standby position (A)). As a result, the time from the start of the clutch release phase to the end of the clutch engagement phase, that is, the time required for shifting gears (hereinafter also referred to as "shifting time"), is also shortened.

[0079] In contrast, as shown in Figure 4(b), when the engine speed is low, the clutch standby position during gear shifting, i.e., the clutch standby position in the gear shift phase, is temporarily changed to the clutch standby position (B) at the timing of transitioning to the gear shift phase, and then maintained at the clutch standby position (A). Thus, when the engine speed is low, clutch drag does not occur, and the clutch standby position in the gear shift phase is maintained at the clutch standby position (A), which is close to the power transmission start point.

[0080] As a result, when the engine speed is low, the clutch speed quickly decreases to the speed of the next gear, and the time required to move the stroke position of the clutch 32 from the clutch standby position to the power transmission start point is shortened compared to when the clutch standby position is clutch standby position (B), thus shortening the time required for the clutch engagement phase.

[0081] Therefore, when the engine speed is low, the shift time is shorter compared to when the clutch is in the clutch standby position (B).

[0082] (During downshift) Figures 5(a) and 5(b) are both timing charts for downshifting, showing the case where the accelerator is pressed by the driver and the engine load is high (Figure 5(a)), and the case where the accelerator is not pressed and the engine load is low (Figure 5(b)).

[0083] As shown in Figure 5(a), when the accelerator is pressed by the driver and the accelerator opening is ON, resulting in a high engine load, for example, in the case of a kickdown with the accelerator opening ON, the clutch standby position during gear shifting, i.e., the clutch standby position in the gear shift phase, changes from clutch standby position (A) to clutch standby position (B). Thus, when the accelerator opening is ON, it can be said that the engine is operating at a high rotational speed.

[0084] As a result, clutch drag does not occur during the gear shift phase, even during downshifting, and the clutch rotation speed increases rapidly. Since clutch drag does not occur, the durability of the clutch can be improved compared to when the clutch is in the clutch standby position (A).

[0085] In other words, in this embodiment, even during downshifting, when the engine speed is high, the synchronization time is shorter compared to when the clutch standby position is not changed (for example, when the clutch standby position is kept at clutch standby position (A)), and therefore the shift time is also shortened.

[0086] In contrast, as shown in Figure 5(b), when the engine load is low, for example, when the accelerator is OFF, the clutch standby position during gear shifting, i.e., the clutch standby position in the gear shift phase, is temporarily changed to the clutch standby position (B) at the moment of transition to the gear shift phase, and then maintained at the clutch standby position (A). Thus, even during downshifting, when the engine load is low, clutch drag does not occur, and the clutch standby position in the gear shift phase is maintained at the clutch standby position (A), which is close to the power transmission start point. In this way, when the accelerator is OFF, it can be said that the engine is operating at a low rotational speed.

[0087] As a result, even during downshifting, when the engine load is low, the clutch rotation speed quickly increases to the rotation speed of the next gear, and compared to when the clutch standby position is clutch standby position (B), the time required to move the stroke position of the clutch 32 from the clutch standby position to the power transmission start point is shortened, thus shortening the time required for the clutch engagement phase.

[0088] Therefore, even during downshifting, if the engine load is low, the shift time will be shorter compared to when the clutch is in the clutch standby position (B).

[0089] Next, referring to Figure 6, we will explain the effects of changing the clutch standby position to clutch standby position (B).

[0090] As shown in Figure 6, when the clutch standby position is changed to clutch standby position (B), the time it takes to return the clutch stroke position to the power transmission start point (hereinafter also referred to as "clutch engagement time") becomes longer compared to when the clutch standby position is clutch standby position (A) (shown by the dashed line in Figure 6).

[0091] Therefore, when the clutch standby position is changed to clutch standby position (B), the time it takes for the engine speed to match the clutch speed becomes longer compared to when the clutch standby position is clutch standby position (A) (shown by the dashed line in Figure 6). This increases the time required for the clutch engagement phase, and consequently, the gear shift time.

[0092] Therefore, in Figures 4(b) and 5(b) of this embodiment, the clutch is initially changed to the clutch standby position (B), but then returned to the clutch standby position (A). Furthermore, when the control device 10 changes the clutch standby position to the clutch standby position (B), it can also increase the clutch engagement speed (movement speed) when returning the clutch 32 from the clutch standby position to the power transmission start point, compared to when the clutch standby position is not changed to the clutch standby position (B).

[0093] Specifically, the control device 10 increases the clutch engagement speed (movement speed) when returning the clutch 32 from the clutch standby position to the power transmission start point until the clutch stroke exceeds a predetermined threshold corresponding to the vicinity of the power transmission start point. Preferably, the predetermined threshold is a clutch stroke position that is on the clutch release side of the power transmission start point and closer to the power transmission start point than the clutch standby position (A).

[0094] In this case, as shown in Figure 7, if the clutch engagement speed when returning the clutch 32 from the clutch standby position to the power transmission start point is increased (shown by a solid line in Figure 7), the time taken for the clutch engagement phase is shortened compared to when the clutch engagement speed is not changed (shown by a dashed line in Figure 7).

[0095] As explained above, in this embodiment, the shift time can be shortened, which in turn makes it possible to shorten the output time of the assist torque of the motor generator 4 for suppressing torque loss during shifting, for example, during upshift shifting.

[0096] Next, with reference to Figure 8, the control performed by the control device 10 according to this embodiment during gear shifting will be described. Figure 8 shows an example in which, in addition to control to change the clutch standby position, control to change the clutch engagement speed is also performed.

[0097] As shown in Figure 8, the control device 10 determines whether or not a gear change has started (step S1). If the control device 10 determines in step S1 that a gear change has not started, it terminates this control.

[0098] If the control device 10 determines that a gear change has started in step S1, it proceeds to the clutch release phase and automatically performs the clutch operation (step S2).

[0099] Next, the control device 10 calculates the clutch release speed (step S3). Then, the control device 10 determines whether or not the clutch release is complete (step S4). The control device 10 can determine whether or not the clutch release is complete by, for example, whether or not the clutch stroke has reached the clutch stroke corresponding to the clutch standby position (B).

[0100] In this embodiment, regardless of the operating state of engine 2, that is, regardless of whether the engine speed is high or not, the clutch standby position is temporarily changed to clutch standby position (B).

[0101] Alternatively, the control device 10 may determine the clutch standby position to either clutch standby position (A) or clutch standby position (B) according to the operating state of the engine 2, without first changing the clutch standby position to clutch standby position (B), and control the clutch 32 to the determined clutch standby position. In this case, the control device 10 can determine, for example, whether clutch release is complete based on whether the clutch stroke has reached the clutch stroke corresponding to the determined clutch standby position.

[0102] If the control device 10 determines in step S4 that the clutch has not been released, it returns to step S3.

[0103] If the control device 10 determines that clutch release is complete in step S4, it proceeds to the gear shift phase (step S5). Subsequently, the control device 10 determines the clutch standby position to either clutch standby position (A) or clutch standby position (B) according to the operating state of the engine 2 (step S6).

[0104] Specifically, when the engine 2 is rotating at high speed, the control device 10 determines the clutch standby position to clutch standby position (B). Conversely, when the engine 2 is rotating at low speed, the control device 10 determines the clutch standby position to clutch standby position (A).

[0105] Next, the control device 10 controls the clutch 32 to the clutch standby position determined in step S6 (step S7). That is, the control device 10 controls the clutch actuator 35 to adjust the clutch 32 to the determined clutch standby position and holds it in that position.

[0106] Next, the control device 10 determines whether the gear shift is complete (step S8). The control device 10 can determine whether the gear shift is complete by, for example, determining whether the gear shift currently engaged in the transmission mechanism 31 is the target gear shift, based on the detection result of the shift position sensor 16.

[0107] If the control device 10 determines in step S8 that the gear shift is not complete, it returns to step S7.

[0108] If the control device 10 determines that the gear shift is complete in step S8, it proceeds to the clutch engagement phase (step S9).

[0109] Subsequently, the control device 10 determines whether the clutch standby position is clutch standby position (A) or not (step S10). If the control device 10 determines in step S10 that the clutch standby position is clutch standby position (A), it proceeds to step S13.

[0110] If the control device 10 determines in step S10 that the clutch standby position is not the clutch standby position (A), that is, if it determines that it is the clutch standby position (B), it controls the clutch 32 at a clutch engagement speed C2 that is faster than the clutch engagement speed C1 described later, that is, it controls the clutch actuator 35 to return the clutch 32 from the clutch standby position toward the power transmission start point at the clutch engagement speed C2 (step S11).

[0111] Next, the control device 10 determines whether the clutch stroke is greater than or equal to a predetermined threshold (step S12). If the control device 10 determines in step S12 that the clutch stroke is not greater than or equal to the predetermined threshold, it returns to step S11.

[0112] If the control device 10 determines in step S12 that the clutch stroke is greater than or equal to a predetermined threshold, it controls the clutch 32 at the clutch engagement speed C1, that is, it controls the clutch actuator 35 to return the clutch 32 from the clutch standby position toward the power transmission start point at the clutch engagement speed C1 (step S13).

[0113] Here, the clutch engagement speed C1 is a clutch engagement speed predetermined by the specifications of the clutch 32, and is slower than the clutch engagement speed C2. For example, it is set to be the same as the clutch engagement speed during gear changes at low engine speeds.

[0114] Next, the control device 10 determines whether or not the clutch 32 has been fully engaged (step S14). If the control device 10 determines in step S14 that the clutch 32 has not been fully engaged, it returns to step S13.

[0115] If the control device 10 determines in step S14 that the engagement of the clutch 32 is complete, it terminates this control.

[0116] As described above, the clutch control device according to this embodiment changes the clutch standby position of the clutch 32 in the disengaged state during gear shifting according to the operating state of the engine 2. By controlling the clutch standby position to an optimal position according to the situation, clutch drag is suppressed and the durability of the clutch 32 is improved, and the time required for the engagement of the clutch 32, such as for gear shifting or starting, is prevented from becoming longer. For example, in situations where clutch drag occurs, by changing the clutch standby position during gear shifting to a position farther away from the power transmission start point, it is possible to prevent the synchronization time from becoming longer, and consequently, to prevent the gear shifting time from becoming longer.

[0117] Furthermore, by changing the clutch standby position during gear shifting to a position further away from the power transmission start point, clutch drag can be suppressed, preventing vibrations in the vehicle body and unintended driving force associated with clutch drag.

[0118] Furthermore, in situations where clutch drag does not occur, maintaining the clutch standby position close to the power transmission start point prevents the time required to transition the clutch 32 to the engaged state, i.e., the time required for the clutch engagement phase, from becoming excessive.

[0119] The clutch control device according to this embodiment changes the clutch standby position to a position further from the power transmission start point when the engine 2 is operating at high speeds, compared to when the engine 2 is operating at low speeds. This suppresses clutch drag associated with the high-speed state of the engine 2, prevents the synchronization time from becoming longer, and consequently prevents the gear shift time from becoming longer.

[0120] In this embodiment, when the clutch standby position is changed to a position further away from the power transmission start point while the engine 2 is rotating at high speed, the clutch engagement speed when returning the clutch 32 from the clutch standby position to the power transmission start point is increased compared to when the clutch standby position is not changed while the engine 2 is rotating at high speed. As a result, the time taken for the clutch engagement phase can be shortened compared to when the clutch standby position is not changed while the engine 2 is rotating at high speed. This further shortens the gear shift time.

[0121] As described above, in the clutch control device according to this embodiment, when the operating state of the engine 2 is a high load state, the clutch standby position may be changed to a position further from the power transmission start point compared to when the operating state of the engine 2 is a low load state. Even in this case, the same effects and advantages as in this embodiment can be obtained.

[0122] While embodiments of the present invention have been disclosed, it will be apparent to those skilled in the art that modifications can be made without departing from the scope of the invention. All such modifications and equivalents are intended to be included in the following claims. [Explanation of symbols]

[0123] 1 vehicle 2 engines 3 Transmission 4. Motor Generator (Motor) 5 drive wheels 10 Control device 11. Crank angle sensor 12. Clutch rotation speed sensor 13. Vehicle speed sensor 14. Accelerator position sensor 15. Clutch position detection sensor 16 Shift position sensor 31. Transmission 31a Input axis 32 Clutch 32a Flywheel 32b Clutch Disc 35 Clutch Actuator 36 Shift Actuator

Claims

1. The engine and A transmission mechanism that changes the rotation of the aforementioned engine at a gear ratio corresponding to the gear stage and outputs the result, A clutch that can be switched between an engaged state for transmitting power between the engine and the transmission mechanism, or a disengaged state for interrupting the transmission of power, A clutch actuator that automatically operates the aforementioned clutch, A clutch control device used in a vehicle equipped with the following: A clutch control device having a control unit that changes the clutch standby position, which is the stroke position of the clutch in the released state during gear shifting, according to the operating state of the engine.

2. The clutch control device according to claim 1, wherein the control unit changes the clutch standby position to a position further away from the clutch power transmission start point when the engine is operating at a high rotational speed compared to when the engine is operating at a low rotational speed.

3. The clutch control device according to claim 1, wherein the control unit changes the clutch standby position to a position further away from the clutch power transmission start point when the engine is operating under a high load condition compared to when the engine is operating under a low load condition.

4. The clutch control device according to claim 2 or 3, wherein when the control unit changes the clutch standby position to a position far from the power transmission start point of the clutch, the clutch engagement speed when returning the clutch from the clutch standby position to the power transmission start point is increased compared to when the clutch standby position is not changed.

5. The clutch control device according to claim 4, further comprising a motor capable of transmitting power to the drive wheels without going through the clutch, wherein the motor outputs assist torque to the drive wheels while the clutch is in the disengaged state during gear shifting.

Images