Vehicle drive device control device

Abstract

To provide a vehicle drive system control device capable of expanding a lock-up region without affecting control of a shift clutch.SOLUTION: A control device is for a vehicle drive system which comprises: a torque converter provided with a lock-up clutch connected to an engine; a transmission mechanism which outputs rotation of the engine by changing a rotation speed; a shift clutch which is arranged between the torque converter and the transmission mechanism; and a clutch actuator which performs automatic clutch operation. A lock-up clutch control section completes switching of the lock-up clutch from a disengaged state to an engaged state when the transmission mechanism is in shifting operation to switch shift stages and the shift clutch is in a disengaged state.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a control device for a vehicle drive device. [Background technology]

[0002] Patent Document 1 discloses a power transmission device that includes a fluid coupling that transmits engine power to the transmission side, a lock-up clutch for mechanically connecting and disconnecting the fluid coupling, and a speed change clutch that is provided between the fluid coupling and the transmission and that is connected and disconnected in response to a gear change operation of the transmission, and that connects the lock-up clutch before the speed change clutch when a peculiar starting operation is performed by the driver. The power transmission device described in Patent Document 1 can prevent poor connection of the lock-up clutch.

[0003] Here, an unusual starting operation by the driver refers to an operation in which, for example, when starting on a downhill slope, the transmission is left in neutral gear position, that is, the vehicle is started without being shifted into any gear, and the transmission is shifted into gear once the vehicle speed has increased to a certain extent. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2005-76667 A Summary of the Invention [Problem to be solved by the invention]

[0005] In a power transmission device having a variable speed clutch between a torque converter with a lock-up clutch and a shift mechanism, it is possible to consider not changing the state of the lock-up clutch during a shift operation so as not to affect the control of the variable speed clutch.

[0006] In this case, the lock-up clutch cannot be engaged until the shift is completed, and therefore the lock-up region cannot be expanded. For this reason, in a power transmission device configured as described above, it is desirable to expand the lock-up region without affecting the control of the shift clutch.

[0007] However, in the power transmission device described in Patent Document 1, no consideration is given to control of the shift clutch and the lock-up clutch during a shift operation, and there is still room for improvement.

[0008] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a control device for a vehicle drive device that can expand the lock-up region without affecting the control of the shift clutch. [Means for solving the problem]

[0009] In order to achieve the above object, the present invention provides a control device for a vehicle drive system including a torque converter with a lock-up clutch connected to an internal combustion engine, a transmission mechanism that changes the speed of the internal combustion engine at a gear ratio corresponding to a gear position and outputs the rotation of the internal combustion engine, a transmission clutch that is provided between the torque converter and the transmission mechanism and can be switched to an engaged state for transmitting power or a disconnected state for disconnecting power, and a clutch actuator that automatically operates the transmission clutch, the control device including a control unit that controls the engagement or release of the lock-up clutch, and the control unit that, when a shift operation to switch the gear position of the transmission mechanism is in progress and the transmission clutch is in the disconnected state, completes the switching of the lock-up clutch from release to engagement. During the shift operation, a pre-charge during shifting can be executed in which the command pressure for the lock-up clutch is temporarily increased before the lock-up clutch is engaged and then the command pressure is maintained at a first pressure and kept in a standby state, and the pre-charge during shifting is completed before the shift clutch is switched to a disengaged state during the shift operation. It has a configuration. Effect of the Invention

[0010] According to the present invention, it is possible to provide a control device for a vehicle drive device that can expand the lock-up region without affecting the control of the speed-change clutch. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram of a vehicle equipped with a control device for a vehicle drive device according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a flowchart showing a flow of processing for lock-up control executed by the control device for a vehicle drive device according to one embodiment of the present invention. [Diagram 3] FIG. 3 is an example of a timing chart during a gear shift operation in a vehicle equipped with a control device for a vehicle drive device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] A control device for a vehicle drive device according to one embodiment of the present invention includes a torque converter with a lock-up clutch connected to an internal combustion engine, a transmission mechanism that changes the speed of the internal combustion engine at a gear ratio corresponding to a gear position and outputs the rotation of the internal combustion engine, a transmission clutch that is provided between the torque converter and the transmission mechanism and can be switched between an engaged state for transmitting power and a disconnected state for disconnecting the power, and a clutch actuator that automatically operates the transmission clutch, and includes a control unit that controls engagement or release of the lock-up clutch, and the control unit is characterized in that when a shift operation for switching the gear position of the transmission mechanism is in progress and the transmission clutch is in the disconnected state, the control device for a vehicle drive device according to one embodiment of the present invention can expand the lock-up region without affecting the control of the transmission clutch. EXAMPLES

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vehicle equipped with a control device for a vehicle drive device according to an embodiment of the present invention will now be described with reference to the drawings.

[0014] As shown in FIG. 1, a vehicle 1 includes an engine 2 as an internal combustion engine, an automatic transmission 3 as a vehicle drive device, drive wheels 4, and a control device 10.

[0015] The engine 2 is formed with a plurality of cylinders. In this embodiment, the engine 2 is configured to perform a series of four strokes, which are an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke, for each cylinder. The engine 2 is a power source for the vehicle 1.

[0016] The automatic transmission 3 is provided in a power transmission path between the engine 2 and drive wheels 4. The automatic transmission 3 has a torque converter 30, a speed change mechanism 31, a speed change clutch 32, and a clutch actuator 33.

[0017] The torque converter 30 is a so-called torque converter with a lock-up clutch, which has a lock-up clutch 35. The torque converter 30 is provided in a power transmission path between the engine 2 and the variable speed clutch 32, and transmits power via a fluid to output the power to a turbine shaft 36.

[0018] A variable speed clutch 32 is connected to the turbine shaft 36. The torque converter 30 amplifies the torque (driving force) input from the crankshaft 21 of the engine 2 by a rotation difference through a fluid, and outputs the amplified torque to the turbine shaft 36 and the variable speed clutch 32. The output of the torque converter 30 is then transmitted to the transmission mechanism 31 via the turbine shaft 36 and the variable speed clutch 32.

[0019] The inside of the torque converter 30 is divided into an apply chamber and a release chamber (not shown) by the lock-up clutch 35. Hydraulic oil is supplied to the apply chamber or the release chamber, and the operating state of the lock-up clutch 35 is switched depending on the hydraulic pressure (hydraulic oil pressure) of the supplied hydraulic oil.

[0020] The lock-up clutch 35 is provided within the torque converter 30, and its operating state can be switched between a connected state (hereinafter referred to as "direct connection") in which the crankshaft 21 and turbine shaft 36 of the engine 2 rotate integrally to transmit power, and a released state in which the direct connection between the crankshaft 21 and the turbine shaft 36 is released and the crankshaft 21 and the turbine shaft 36 transmit power via a fluid (hydraulic oil).

[0021] The lock-up clutch 35 is switched to the engaged state by supplying hydraulic pressure (hereinafter, this hydraulic pressure is referred to as "engagement hydraulic pressure") to the apply chamber and discharging hydraulic oil from the release chamber. Conversely, the lock-up clutch 35 is switched to the released state by supplying hydraulic pressure (hereinafter, this hydraulic pressure is referred to as "release hydraulic pressure") to the release chamber and discharging hydraulic oil from the apply chamber.

[0022] The transmission mechanism 31 is provided in a power transmission path between the transmission clutch 32 and the drive wheels 4, and has an input shaft 37 connected to the transmission clutch 32, and an output shaft 38 connected to the drive wheels 4 via a differential (not shown). The transmission mechanism 31 converts the driving force input from the transmission clutch 32 to the input shaft 37, changes the rotational speed, and outputs it from the output shaft 38.

[0023] The transmission mechanism 31 changes the rotation of the engine 2, which is output from the engine 2 and transmitted to an input shaft 37, at a gear ratio corresponding to one of a plurality of gears, which will be described later, selected, and outputs the changed rotation to an output shaft 38. The rotation and driving force output to the output shaft 38 are transmitted to the drive wheels 4 via a differential, not shown.

[0024] The transmission mechanism 31 is configured to be capable of forming a plurality of gear stages with different gear ratios by a plurality of gear pairs with different gear ratios. The gear stages in the transmission mechanism 31 are automatically switched by a shift actuator (not shown). In detail, the control device 10 judges whether a gear shift is necessary by referring to a gear shift map based on the vehicle speed and the depression amount of the accelerator pedal, and outputs a gear shift command to the shift actuator. Then, the shift actuator that receives the gear shift command operates to perform the gear shift.

[0025] The variable speed clutch 32 is provided in a power transmission path between the torque converter 30 and the transmission mechanism 31. The variable speed clutch 32 has a clutch wheel disc 32a connected to the turbine shaft 36 so as to rotate integrally therewith, and a clutch disc 32b connected to the input shaft 37 of the transmission mechanism 31 so as to rotate integrally therewith.

[0026] The variable speed clutch 32 is a dry single-plate clutch that can be switched between an engaged state in which the clutch disc 32b is pressed against the clutch wheel disc 32a to rotate together with the clutch wheel disc 32a to transmit power, and a disconnected state in which the clutch disc 32b is separated from the clutch wheel disc 32a to disconnect the power transmission between the clutch wheel disc 32a and the clutch disc 32b. In other words, the variable speed clutch 32 transmits power between the turbine shaft 36 and the input shaft 37 in the engaged state, and disconnects the power transmission between the turbine shaft 36 and the input shaft 37 in the disconnected state.

[0027] The operation of switching the speed-change clutch 32 between an engaged state and a disengaged state (hereinafter referred to as “clutch operation”) is performed automatically by a clutch actuator 33.

[0028] The clutch actuator 33 is electrically connected to the control device 10, and performs clutch operation of the speed change clutch 32 based on a command from the control device 10. Specifically, the clutch actuator 33 moves a release bearing (neither of which is shown) in the axial direction of the input shaft 37 using a release fork or the like, and causes the release bearing to elastically deform a diaphragm spring of the clutch wheel disc 32a, thereby disengaging the speed change clutch 32. The clutch actuator 33 also moves the release bearing from the disengaged position in the opposite direction to that used for disengaging the clutch, thereby releasing the diaphragm spring from elastic deformation, thereby disengaging the speed change clutch 32.

[0029] The control device 10 is composed of a computer unit having a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory for storing backup data, etc., an input port, and an output port.

[0030] The ROM of the computer unit stores various constants, various maps, and the like, as well as a program for causing the computer unit to function as the control device 10. That is, the CPU executes the program stored in the ROM using the RAM as a working area, whereby the computer unit functions as the control device 10 in this embodiment.

[0031] The control device 10 is connected to various devices such as the shift actuator, clutch actuator 33, and hydraulic control device 40 described above (not shown), as well as various sensors such as a crank angle sensor 50, a turbine rotation speed sensor 51, a clutch rotation speed sensor 52, a clutch position detection sensor 53, a lock-up hydraulic sensor 54, a vehicle speed sensor 55, and an accelerator sensor 56.

[0032] The hydraulic control device 40 controls the hydraulic pressure supplied to the lock-up clutch 35 and the clutch actuator 33 of the torque converter 30. The hydraulic control device 40 switches the lock-up clutch 35 between an engaged state and a released state by adjusting the magnitude of the hydraulic pressure supplied to the lock-up clutch 35 based on a command from the control device 10. The hydraulic control device 40 switches the variable speed clutch 32 between an engaged state and a released state by adjusting the magnitude of the hydraulic pressure supplied to the clutch actuator 33 based on a command from the control device 10.

[0033] The crank angle sensor 50 detects the rotation angle (hereinafter referred to as the "crank angle") of the crankshaft 21. The control device 10 calculates the engine speed, which is the rotation speed of the engine 2 (the rotation speed of the crankshaft 21), based on the information indicating the crank angle input from the crank angle sensor 50.

[0034] The turbine rotation speed sensor 51 detects the rotation speed (hereinafter referred to as "turbine rotation speed") of the turbine shaft 36. The clutch rotation speed sensor 52 detects the rotation speed (hereinafter referred to as "clutch rotation speed") of the clutch disc 32b and the input shaft 37.

[0035] The clutch position detection sensor 53 detects the position of the release bearing in the transmission clutch 32 or the position of a part such as a release fork that moves in relation to the moving state of the release bearing (hereinafter referred to as the "clutch position"). The clutch position indicates the state of the transmission clutch 32 (disengaged state / half-clutch state / engaged state), and can also be considered to indicate the magnitude of the torque transmitted by the transmission clutch 32. The lock-up oil pressure sensor 54 detects the hydraulic oil pressure supplied to the lock-up clutch 35. In this embodiment, at least the engagement oil pressure acting on the apply chamber is detected, but the oil pressure acting on the apply chamber may be estimated or detected based on the release oil pressure acting on the release chamber. The vehicle speed sensor 55 detects the vehicle speed, which is the speed of the vehicle 1. The accelerator sensor 56 detects the amount of depression of an accelerator pedal (not shown) by the driver. The accelerator sensor 56 may also detect the movement of a throttle valve that changes in conjunction with the amount of depression of the accelerator pedal.

[0036] The control device 10 functions as a clutch control unit 101 that controls the variable speed clutch 32 by referring to a map (not shown) that defines the relationship between the clutch position and the clutch transmission torque based on the clutch position detected by the clutch position detection sensor 53.

[0037] The control device 10 has a function as a lockup clutch control unit 102 that controls the engagement or release of the lockup clutch 35. For example, when a predetermined lockup condition is established, the control device 10 executes lockup control that controls the hydraulic control device 40 so as to switch the lockup clutch 35 from a released state to an engaged state. The lockup clutch control unit 102 in this embodiment constitutes a control unit.

[0038] In this embodiment, the predetermined lock-up condition is, for example, when the vehicle speed is equal to or greater than a predetermined vehicle speed. The predetermined lock-up condition is not limited to this, and may be other conditions, or the state of the gear position and the vehicle speed may be the predetermined lock-up condition.

[0039] In the above-mentioned lockup control, the control device 10 executes pre-charge, which temporarily increases the command pressure for the lockup clutch 35 (hereinafter referred to as "LU command pressure") to a predetermined pre-charge pressure before the lockup clutch 35 is engaged, and then waits while maintaining the predetermined pressure. Pre-charge is an operation for filling the apply chamber with hydraulic oil in order to shorten the response time of the lockup clutch 35 (the time from when a lockup command is issued until the lockup clutch 35 actually engages), and the command pressure is set taking into consideration the response delay due to the flow resistance of the hydraulic oil itself. Specifically, pre-charge aims to bring the lockup clutch 35 into a state where it starts engaging (transmitting power) early, and in this embodiment, it also means waiting in a state just before engagement so that the operation of engaging the lockup clutch 35 can start immediately when other conditions are in a state where the lockup clutch 35 can start engaging.

[0040] The above-mentioned LU command pressure is a hydraulic pressure commanded from the control device 10 to the hydraulic control device 40, and is a command value of the differential pressure between the engagement hydraulic pressure and the release hydraulic pressure.

[0041] In the above-mentioned lockup control, when the lockup clutch 35 is to be fully engaged, the control device 10 increases the LU command pressure to the engagement command pressure P5, and engages the lockup clutch 35 in one go. This increases the hydraulic pressure of the lockup clutch 35 in one go, and the lockup clutch 35 quickly completes engagement. The engagement command pressure P5 is set to a pressure higher than each pre-charge pressure, which will be described later. When maintaining the engagement of the lockup clutch 35, the LU command pressure may be left at the engagement command pressure P5, but it can be reduced to an LU command pressure lower than the engagement command pressure P5 within a range that does not cause slippage.

[0042] In this embodiment, there are various types of precharge for the lockup clutch 35, including at least a normal precharge, a precharge during gear shifting, and a precharge at start-up, and the control device 10 selectively executes these precharges depending on the situation.

[0043] Normal precharge is executed, for example, in a situation other than during a shift operation for switching gear stages in the transmission mechanism 31 or when the vehicle 1 is not starting, and is a precharge in which the LU command pressure is temporarily increased to a normal precharge pressure (hereinafter referred to as "normal precharge pressure Pn") before the engagement of the lock-up clutch 35, and then the LU command pressure is kept at the first pressure P2 while waiting. In other words, normal precharge is a precharge control in a state in which the transmission clutch 32 is engaged, and is a precharge control in a state in which there is no release control or operation of the transmission clutch 32 to release or to transition between the released and engaged states.

[0044] Pre-charge during gear shifting is executed during a gear shift operation to switch gear positions in the gear change mechanism 31, and is a pre-charge in which the LU command pressure is temporarily increased to a pre-charge pressure during gear shifting (hereinafter referred to as "pre-charge pressure during gear shifting P3") before the lock-up clutch 35 is engaged, and then the LU command pressure is kept at the first pressure P2 and kept on standby. In other words, pre-charge during gear shifting is a pre-charge control when the gear shift clutch 32 is disengaged or in transition between the disengaged and engaged states.

[0045] The precharge during gear shifting is executed during a gear shift operation, and more specifically, it is executed in either of the following cases (1) or (2). (1) When a specified lockup condition is met and a gear shift command is issued at the same time. (2) When a predetermined lock-up condition is established after a gear shift command is issued, and it is determined that the pre-charge during gear shifting can be completed before the gear shift clutch 32 switches from the engaged state to the disengaged state.

[0046] The first pressure P2 is a pressure lower than the mid-shift pre-charge pressure P3 and the normal pre-charge pressure Pn, and is a pressure that is increased in advance so that the engagement of the lock-up clutch 35 can be completed quickly, specifically, it is a command pressure that realizes a pressure at which the lock-up clutch 35 is in a state (maintains a state) at which it starts to engage (transmit power), and is determined in advance by experiment and stored in the ROM of the control device 10. In this embodiment, the standby pressure for both the normal pre-charge and the mid-shift pre-charge is the first pressure P2, but they may be different pressures.

[0047] The pre-charge pressure during gear shifting P3 and the normal pre-charge pressure Pn are LU command pressures that are temporarily increased so that the pressure difference between the engagement hydraulic pressure and the release hydraulic pressure of the lock-up clutch 35 quickly reaches the first pressure P2. As described above, pre-charge is an operation for filling the apply chamber with hydraulic oil in order to shorten the response time of the lock-up clutch 35, and the command pressure is set taking into consideration the response delay caused by the flow resistance of the hydraulic oil itself, etc. For this reason, the pre-charge command pressure and pre-charge time are set taking into consideration the viscosity of the hydraulic oil, which depends on temperature, and the flow characteristics of the oil passages and valves, etc.

[0048] Since the pre-charge during shifting is to prepare for completing the engagement of the lock-up clutch 35 while the shift clutch 32 is in a disengaged state, the pre-charge during shifting is completed during the shift operation before the shift clutch 32 switches from an engaged state to a disengaged state. However, since the shift clutch 32 is in a state of transmitting power (engaged state or in transition from an engaged state to a disengaged state) when the pre-charge during shifting is performed in this manner, if the pre-charge pressure during shifting P3 is made too high, the operating oil pressure of the lock-up clutch 35 will suddenly increase, and the lock-up clutch 35 will engage and transmit torque, which may cause a torque fluctuation (shock). In particular, the pre-charge during shifting is performed when the shift clutch 32 changes state from an engaged state to a disengaged state, and the driving force (input) input from the torque converter 30 to the shift clutch 32 will change when the torque transmitted by the shift clutch 32 is changing, so there is a high possibility of a shock being felt by the occupant. Furthermore, when the vehicle is accelerating, the change in driving force is also large, and this is particularly noticeable. Such shock is transmitted to the drive wheels 4, causing changes in the acceleration of the vehicle body (vibrations), which reduces the marketability of the vehicle.

[0049] Therefore, in this embodiment, the shift-in-progress pre-charge pressure P3 is set to a value lower than the normal pre-charge pressure Pn, thereby suppressing the occurrence of shocks that would otherwise accompany a sudden increase in the hydraulic pressure of the lock-up clutch 35.

[0050] The start-up pre-charge is executed when the vehicle 1 starts, specifically when it is detected that the driver has depressed the accelerator pedal. The start-up pre-charge is a pre-charge in which the LU command pressure is temporarily increased to the start-up pre-charge pressure (hereinafter referred to as "start-up pre-charge pressure P4"), and then the LU command pressure is maintained at the second pressure P1 and kept in standby.

[0051] The second pressure P1 is lower than the above-mentioned first pressure P2 and also lower than the starting pre-charge pressure P4, and is a pressure that is increased in advance so that the filling of hydraulic oil for removing backlash in a lock-up clutch piston (not shown) can be completed early, and is experimentally determined in advance and stored in the ROM of the control device 10.

[0052] The starting pre-charge pressure P4 is an LU command pressure that is temporarily increased so that the differential pressure between the engagement oil pressure and the release oil pressure of the lock-up clutch 35 reaches the second pressure P1 early, and is a pressure higher than the above-mentioned pre-charge pressure P3 during gear shifting and the normal pre-charge pressure Pn.

[0053] The start-up pre-charge is set to be completed in a shorter time than the above-mentioned pre-charge during gear shifting. Even if torque transmission occurs in the lock-up clutch 35 and some torque fluctuation occurs due to the temporary increase in the LU command pressure in a short time, the driver will not feel uncomfortable when the vehicle 1 is started. In addition, when the vehicle 1 is started, a delay occurs in the actual flow of hydraulic oil due to the high viscosity of the hydraulic oil and the flow resistance of the oil passage, so that a situation in which the actual hydraulic oil pressure rises suddenly even if the LU command pressure is changed suddenly does not occur. Therefore, no problem occurs even if the start-up pre-charge is completed in a short time.

[0054] In contrast, the pre-charge during gear shifting is executed for a longer period of time than the pre-charge at start. While the vehicle 1 is running, including while the vehicle 1 is shifting, the driver is likely to feel changes in acceleration, and so even a slight torque fluctuation may cause the driver to feel uncomfortable. In addition, while the vehicle 1 is running, including while the vehicle 1 is shifting, the viscosity of the hydraulic oil may decrease or the flow resistance may change depending on the temperature, resulting in high responsiveness of the actual hydraulic oil pressure.

[0055] For this reason, if the LU command pressure is suddenly increased in a short period of time, the actual hydraulic pressure may also suddenly increase, which may cause the torque fluctuations described above, etc. Therefore, it is preferable that the pre-charge during gear shifting is performed for a longer period of time than the pre-charge at start-up, as described above.

[0056] (Lock-up control) Next, the flow of processing for lock-up control executed by the control device 10 of this embodiment will be described with reference to FIG.

[0057] 2, the control device 10 determines whether or not a predetermined lock-up condition is satisfied (step S1). If the control device 10 determines in step S1 that the predetermined lock-up condition is not satisfied, the control device 10 repeats the process of step S1.

[0058] When the control device 10 determines in step S1 that the predetermined lock-up condition is satisfied, it determines whether or not a gear shift command has already been issued, i.e., whether or not a gear shift command was issued when the predetermined lock-up condition was satisfied (step S2).

[0059] The control device 10 operates a shift actuator (not shown) to switch gears in the transmission mechanism 31 by referring to a gear shift map based on the vehicle speed and the depression amount of the accelerator pedal (gear-shift-related parts other than the gear shift clutch 32 are omitted in FIG. 1), and can determine whether or not a gear shift command has been issued. The gear shift map is a map in which the vehicle speed and the depression amount of the accelerator pedal correspond to gear shift lines, and is obtained in advance by experiment and stored in the ROM of the control device 10.

[0060] If the control device 10 determines in step S2 that there is no gear shift command, it executes normal precharge (step S9) and proceeds to the process of step S8.

[0061] When the control device 10 determines in step S2 that a shift command has been issued, it determines whether the shift clutch 32 is in transition from an engaged state to a disengaged state (step S3). The control device 10 can determine whether the shift clutch 32 is in transition from an engaged state to a disengaged state, for example, based on the clutch position. In addition, the control device 10 can determine whether the shift clutch 32 is in transition from an engaged state to a disengaged state, for example, based on the time elapsed since the shift command. Whether the shift clutch 32 is in transition from an engaged state to a disengaged state may be determined by other methods without being limited to the above-mentioned methods.

[0062] When the control device 10 determines in step S3 that the shift clutch 32 is not in transition from an engaged state to a disengaged state, the control device 10 ends the lockup control. That is, a predetermined lockup condition is satisfied and the lockup clutch 35 is to be engaged, but the shift control for the transmission mechanism 31 and the shift clutch 32 is in an advanced state, and the lockup clutch 35 is not engaged (specifically, precharged) until the shift control is terminated so as not to adversely affect the shift control. In contrast, when the control device 10 determines in step S3 that the shift clutch 32 is in transition from an engaged state to a disengaged state, the control device 10 changes the LU command pressure to the shift-in-progress precharge pressure P3 (step S4). That is, if the shift control has just started, the control device 10 starts engaging the lockup clutch 35 (specifically, precharged).

[0063] Next, the control device 10 determines whether or not a predetermined time (between time t1 and time t2) has elapsed for the instruction to set the LU command pressure to the pre-charge pressure during shifting P3 (step S5). The predetermined time is set to a time that is at least shorter than the time it takes for the shift clutch 32 to switch from the engaged state to the disengaged state. If the control device 10 determines in step S5 that the predetermined time has not elapsed, it repeats the process of step S5. In other words, the control device 10 continues to issue an instruction to pre-charge the LU command pressure to the pre-charge pressure during shifting P3 until the predetermined time has elapsed.

[0064] When the control device 10 determines in step S5 that the predetermined time has elapsed, it changes the LU command pressure from the pre-charge pressure during shifting P3 to the first pressure P2 (step S6). In other words, the control device 10 issues a command to maintain a working oil pressure state at which the engagement of the lock-up clutch 35 can be started, assuming that the pre-charge has been completed after the predetermined time has elapsed.

[0065] Next, the control device 10 determines whether the shift clutch 32 is in a disengaged state (step S7). If the control device 10 determines in step S7 that the shift clutch 32 is not in a disengaged state, it determines that the shift clutch 32 has not yet been shifted to a disengaged state, and repeats the process of step S7. In other words, the control device 10 waits with the LU command pressure set to the first pressure P2 until the shift clutch 32 is disengaged in step S7.

[0066] If the control device 10 determines in step S7 that the speed-change clutch 32 is in the disengaged state, the process proceeds to step S8.

[0067] In step S8, the control device 10 changes the LU command pressure from the first pressure P2 to the engagement command pressure P5 (step S8), and ends this lock-up control. By executing step S8, the hydraulic pressure of the hydraulic pressure is increased, and the lock-up clutch 35 is engaged.

[0068] In this way, the control device 10 can execute the operation of changing the state of the lockup clutch 35 to engagement only when the shift clutch 32 is transitioning from an engaged state to a disengaged state. During other shift operations, the control device 10 suppresses the operation of changing the state of the lockup clutch 35 to engagement. When the shift clutch 32 is in a disengaged state during a shift operation, the control device 10 instructs the lockup clutch 35 to be switched from released to engaged. The operation of switching the lockup clutch 35 from released to engaged can be completed in a short time because a precharge is also performed, so that the shift stage in the shift mechanism 31 can be completed in a time shorter than the time it takes to change from 1st gear to 2nd gear.

[0069] Next, a transition of the LU command pressure during a gear shift operation from 1st gear to 2nd gear in the vehicle 1 of this embodiment will be described with reference to Fig. 3. Fig. 3 shows an example in which a gear shift command from 1st gear (denoted as "1st" in Fig. 3) to 2nd gear (denoted as "2nd" in Fig. 3) and a lock-up command, i.e., the establishment of a predetermined lock-up condition, are issued simultaneously.

[0070] As shown in Figure 3, at time t0, a specified lockup condition is not satisfied, i.e., no lockup instruction has been issued (indicated as "OFF" in Figure 3), and the vehicle 1 is accelerating in first gear.

[0071] At time t0, the clutch position is a position when the variable speed clutch 32 is engaged (indicated as "engaged" in FIG. 3), and the LU command pressure is maintained at the second pressure P1. In addition, since the vehicle is accelerating, the engine speed Ne, the turbine speed Nt, and the clutch speed Nc are increasing over time.

[0072] After that, at time t1, when a shift command from 1st gear to 2nd gear is issued and at the same time a lock-up command is issued (indicated as "ON" in FIG. 3), variable speed clutch 32 starts to transition from an engaged state to a disengaged state. As a result, the clutch position transitions from a position indicating engagement to a position when variable speed clutch 32 is in a disengaged state (indicated as "disengaged" in FIG. 3).

[0073] Furthermore, at time t1, pre-charge during gear shifting is started, and the LU command pressure is increased from the second pressure P1 to the pre-charge pressure during gear shifting P3.

[0074] Then, at time t2, when a predetermined time has elapsed since the start of the pre-charge during gear shifting, the LU command pressure is changed to the first pressure P2, and the pre-charge during gear shifting is completed. Also, around time t2, as the gear shift clutch 32 transitions from the engaged state to the disengaged state, the clutch rotation speed Nc starts to decrease relative to the turbine rotation speed Nt. As a result, the driving force of the vehicle 1 decreases, and the acceleration of the vehicle 1 also decreases.

[0075] Then, at time t3, when the clutch position reaches a position indicating disengagement and shift clutch 32 enters the disengaged state, the LU command pressure is increased from first pressure P2 to engagement command pressure P5. This starts the switching of lockup clutch 35 from the released state to the engaged state, and thereafter, while shift clutch 32 is disengaged (in the example shown in FIG. 3, between time t3 and time t4), lockup clutch 35 is fully engaged. In other words, lockup clutch 35 switches to the engaged state, and the control to engage lockup clutch 35 is completed.

[0076] 3, at time t3, the LU command pressure is increased from the first pressure P2 to the engagement command pressure P5 at the same time that the shift clutch 32 is disengaged, but if it is possible to switch the lock-up clutch 35 to the engaged state while the shift clutch 32 is disengaged, the LU command pressure does not have to be increased from the first pressure P2 to the engagement command pressure P5 at the same time that the shift clutch 32 is disengaged. For example, the LU command pressure may be increased from the first pressure P2 to the engagement command pressure P5 after time t3.

[0077] As described above, between time t3 and time t4, when the lock-up clutch 35 switches to the engaged state, the engine speed Ne and the turbine speed Nt are synchronized, and as a result, the speed difference between the engine speed Ne and the turbine speed Nt (denoted as "|Ne-Nt|" in Figure 3) becomes zero.

[0078] Furthermore, between time t3 and time t4, the gear position in the transmission mechanism 31 is changed from 1st gear to 2nd gear. As a result, from time t3, the clutch rotation speed Nc starts to decrease toward the rotation speed corresponding to the 2nd gear, and around time t4, the change to the 2nd gear in the transmission mechanism 31 is almost completed, and the clutch rotation speed Nc becomes the rotation speed corresponding to the 2nd gear.

[0079] Thereafter, at time t4, switching of variable speed clutch 32 from the disengaged state to the engaged state begins, and the clutch position gradually transitions toward a position indicating engagement.

[0080] After time t4 has elapsed, engine speed Ne decreases so as to synchronize with clutch speed Nc as variable speed clutch 32 transitions to an engaged state. Then, acceleration resumes as engine power is transmitted, and clutch speed Nc increases (vehicle speed increases).

[0081] Thereafter, at time t5, when the clutch position reaches a position indicating engagement and the shift clutch 32 enters an engaged state, the engine speed Ne and turbine speed Nt are synchronized with the clutch speed Nc, and the shift to second gear is completed.

[0082] As described above, the control device for a vehicle drive device in this embodiment is configured to complete the switching of the lock-up clutch 35 from released to engaged when a gear shift operation is in progress and the gear shift clutch 32 is in a disengaged state.

[0083] With this configuration, the control device for a vehicle drive system according to this embodiment can engage lock-up clutch 35 before the shift is completed, without waiting for the engagement of lock-up clutch 35 until the shift is completed. This makes it possible to expand the lock-up region without affecting the control of variable-speed clutch 32. This makes it possible to improve fuel efficiency.

[0084] In addition, the control device for a vehicle drive device in this embodiment is configured to complete the switching of lock-up clutch 35 from released to engaged while shift clutch 32 is in the disengaged state during a shift operation when a specified lock-up condition is met and a shift command is issued simultaneously, or when a specified lock-up condition is met after a shift command is issued and it is determined that pre-charge during shifting can be completed before shift clutch 32 switches from the engaged state to the disengaged state.

[0085] As a result, the control device for a vehicle drive device in this embodiment does not need to change the control of the variable speed clutch 32 to take into account the engagement of the lock-up clutch 35, thereby preventing the control of the variable speed clutch 32 from becoming complicated.

[0086] Furthermore, the control device for a vehicle drive device according to this embodiment can engage the lock-up clutch 35 before the shift is completed without waiting for the shift to be completed and without affecting the control of the shift clutch 32.

[0087] In addition, the control device for a vehicle drive device in this embodiment is capable of executing a pre-charge during a gear shift before the lock-up clutch 35 is engaged during a gear shift operation, and is configured to complete the pre-charge during a gear shift before the gear shift clutch 32 during the gear shift operation switches to a disengaged state.

[0088] With this configuration, the control device for the vehicle drive device according to this embodiment can reduce the time required for the lock-up clutch 35 to switch from the released state to the engaged state by performing pre-charge during gear shifting.

[0089] In addition, the control device of the vehicle drive device in this embodiment is capable of executing start-up pre-charge when the vehicle 1 starts, and the start-up pre-charge pressure P4 in the start-up pre-charge is set to a pressure higher than the pre-charge pressure P3 during gear shifting.

[0090] As a result, the control device for a vehicle drive device according to this embodiment can complete eliminating backlash in the lock-up clutch piston earlier when the vehicle 1 starts moving than during a gear shift operation.

[0091] Moreover, the control device for a vehicle drive device according to this embodiment is configured to execute the pre-charge during gear shifting for a longer period of time than the pre-charge at start-up.

[0092] With this configuration, the control device for a vehicle drive device according to this embodiment can suppress a sudden increase in the actual operating oil pressure, and can suppress the driver from feeling uncomfortable due to torque fluctuations.

[0093] In this embodiment, for example, at time t3 in Fig. 3, an example has been described in which the LU command pressure is instantly increased from the first pressure P2 to the engagement command pressure P5, but the present invention is not limited to this, and the LU command pressure may be gradually increased from the first pressure P2 to the engagement command pressure P5. Also, even when the speed change clutch 32 is not in the disengaged state, the LU command pressure may be gradually increased toward the engagement command pressure P5.

[0094] In this case, the rate of increase of the LU command pressure is preferably set to be faster when the shift clutch 32 is disengaged than when the shift clutch 32 is not disengaged. This is because the lock-up clutch 35 needs to be switched to the engaged state while the shift clutch 32 is in the disengaged state during a gear shift operation.

[0095] Although an embodiment of the invention has been disclosed, it will be apparent to one of ordinary skill in the art that modifications may be made therein without departing from the spirit and scope of the invention, and it is intended that all such modifications and equivalents be included in the following claims. [Explanation of symbols]

[0096] 1 vehicle 2. Engine (internal combustion engine) 3 Automatic transmission (vehicle drive system) 4 Drive wheels 10 Control device 21 Crankshaft 30 Torque converter 31 Transmission mechanism 32 Shift clutch 32a clutch wheel disc 32b clutch disc 33 Clutch actuator 35 Lock-up clutch 36 Turbine shaft 37 Input shaft 38 Output shaft 40 Hydraulic control device 50 Crank angle sensor 51 Turbine speed sensor 52 Clutch rotation speed sensor 53 Clutch position detection sensor 54 Lockup oil pressure sensor 55 Vehicle speed sensor 56 Accelerator Sensor 101 Clutch control unit 102 Lock-up clutch control unit (control unit) Pn Normal precharge voltage P1 Second pressure P2 First pressure P3 Precharge pressure during shifting P4 Precharge pressure at start P5 Fastening pressure

Claims

1. a torque converter with a lock-up clutch connected to the internal combustion engine; a speed change mechanism that changes the rotation of the internal combustion engine at a speed change ratio corresponding to a speed change stage and outputs the rotation; a variable speed clutch that is provided between the torque converter and the speed change mechanism and that can be switched between an engaged state in which power is transmitted and a disconnected state in which power is disconnected; A clutch actuator that automatically operates the speed change clutch; A control device for a vehicle drive device comprising: A control unit is provided for controlling engagement or release of the lock-up clutch, The control unit completes switching of the lock-up clutch from release to engagement when a shift operation for switching the gear stage of the transmission mechanism is in progress and the shift clutch is in the disengaged state, During the shift operation, a pre-charge during shifting can be executed in which a command pressure for the lock-up clutch is temporarily increased before the lock-up clutch is engaged and then the command pressure is kept at a first pressure, 4. The control device for a vehicle drive system, wherein the precharge during the shift is completed before the shift clutch during the shift operation is switched to a disengaged state.

2. The control unit is capable of executing a start pre-charge in which, when the vehicle starts, a command pressure for the lock-up clutch is temporarily increased and then the command pressure is maintained at a second pressure lower than the first pressure, 2. The control device for a vehicle drive device according to claim 1, wherein the command pressure temporarily increased before being maintained at the second pressure during the start precharge is higher than the command pressure temporarily increased during the shift precharge.

3. 3. The control device for a vehicle drive device according to claim 2, wherein the pre-charge during gear shifting is executed for a longer period of time than the pre-charge at start-up.

4. 4. The control device for a vehicle drive device according to claim 1, wherein the increasing rate of the command pressure for engaging the lock-up clutch is faster when the variable speed clutch is in the disengaged state than when the variable speed clutch is not in the disengaged state.

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