JP2013164127A - Vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid an evil (for example, a shock) by failure of a solenoid valve.SOLUTION: In a vehicle, hydraulic pressure supplied to a lockup clutch (LUC) and a power transmission clutch (FC) is switched in response to output of first and second ON-OFF solenoid valves (S1 and S2), and an ECU controls the S1 and S2 in any of a plurality of control modes including a first mode of releasing the LUC and engaging the FC by turning on the S1 and turning on the S2, a second mode of releasing the LUC and engaging the FC by turning off the S1 and turning off the S2 and a third mode of supplying output hydraulic pressure of a linear solenoid valve to the LUC and engaging the FC by turning off the S1 and turning on the S2. The ECU prohibits transfer to the third mode (S12), when releasing the FC (YES in S11) in a control mode except for the third mode (NO in S10).

Description

  The present invention relates to a vehicle including a torque converter with a lock-up clutch and a power transmission clutch on a power transmission path from an engine to driving wheels.

  Japanese Patent Laid-Open No. 2009-257424 (Patent Document 1) discloses an abnormality caused by a failure of each solenoid valve stored in advance in a transmission including a plurality of solenoid valves used for at least one of a plurality of controls. A technique is disclosed that determines which combination of phenomenon combinations matches the combination of actual abnormal phenomena, and identifies that the solenoid valve corresponding to the combination determined to match is broken.

JP 2009-257424 A JP 2007-107598 A

  By the way, if a control valve (solenoid valve) breaks down during a certain control mode, the transition to another control mode is restricted or the transition to another control mode is prevented so that no adverse effects (such as shocks) due to the failure occur. It is desirable to incorporate a control for performing special processing in advance for the transition. However, Patent Document 1 does not show any such control.

  The present invention has been made to solve the above-described problems, and an object thereof is to avoid an adverse effect (for example, a shock or the like) due to a failure of a control valve.

  The vehicle according to the present invention includes a torque converter with a lock-up clutch and a power transmission clutch on a power transmission path from the engine to the drive wheels. The vehicle includes a linear solenoid valve that adjusts and outputs the original pressure to a hydraulic pressure corresponding to a linear command pressure, a first and second on / off valve that outputs hydraulic pressure in the on state and does not output hydraulic pressure in the off state, A switching valve for switching the hydraulic pressure supplied to the lockup clutch and the power transmission clutch according to the combination of the hydraulic pressures input from the second on / off valve, a control device for controlling the linear solenoid valve and the first and second on / off valves Is provided. The switching valve is configured to supply a predetermined release hydraulic pressure to the lockup clutch and a predetermined engagement hydraulic pressure to the power transmission clutch when both the first and second on / off valves are in an on state or an off state. When the first on / off valve is off and the second on / off valve is on, the output hydraulic pressure of the linear solenoid valve is supplied to the lockup clutch and the predetermined engagement hydraulic pressure is supplied to the power transmission clutch. When the first on / off valve is in the on state and the second on / off valve is in the off state, the predetermined release hydraulic pressure is supplied to the lockup clutch, and the output hydraulic pressure of the linear solenoid valve is supplied to the power transmission clutch. Switch to the third state. The control device sets both the first and second on / off valves to the on state, thereby setting the switching valve to the first state and setting the linear command pressure to substantially zero, and the first and second on / off valves. By switching both to the off state, the switching valve is set to the first state and the linear command pressure is made substantially zero, and the first on / off valve is turned off and the second on / off valve is turned on. The first and second on / off valves are controlled in any of a plurality of control modes including a third mode in which the switching valve is set to the second state and the linear command pressure is adjusted to control the engagement state of the lockup clutch. To do. The control device limits the transition to the third mode when the power transmission clutch is released during a control mode other than the third mode.

  Preferably, the control device executes an increase control for increasing the output hydraulic pressure of the linear solenoid valve during the restriction on the transition to the third mode.

  Preferably, when the power transmission clutch is engaged by the increase control, the control device releases the restriction on the transition to the third mode and allows the transition to the third mode.

  Preferably, in the plurality of control modes, in addition to the first, second, and third modes, the first on / off valve is turned on and the second on / off valve is turned off to bring the switching valve into the third state. And a fourth mode.

  Preferably, the control device allows the shift to the third mode when the power transmission clutch is not released during the control mode other than the third mode.

  Preferably, the vehicle further includes a continuously variable transmission. The power transmission clutch is a forward / reverse clutch provided between the torque converter and the continuously variable transmission.

  According to the present invention, it is possible to avoid adverse effects (for example, shocks) caused by a malfunction of the control valve.

It is a figure which shows schematic structure of a vehicle. It is a control block diagram which shows the equipment connected to ECU and ECU. FIG. 3 is a first diagram illustrating a configuration of a part of a hydraulic control circuit; FIG. 2 is a second diagram illustrating a configuration of a part of a hydraulic control circuit. FIG. 6 is a third diagram illustrating a configuration of a part of a hydraulic control circuit. FIG. 6 is a diagram (part 4) illustrating a partial configuration of the hydraulic control circuit; It is the figure which put together the control mode which ECU performs. It is a figure for demonstrating the aspect of lockup clutch control. It is the figure which showed for example the control example equivalent to the past at the time of S1 ON failure. It is a flowchart which shows the process sequence of ECU. It is the figure which showed the example of control which ECU performs.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  FIG. 1 is a diagram showing a schematic configuration of a vehicle 1 according to the present embodiment. The vehicle 1 travels by transmitting the power of the engine 200 to the drive wheels 800. On the power transmission path from the engine 200 to the drive wheel 800, a torque converter 300 with a lock-up clutch 308, a forward / reverse clutch 400, a belt-type continuously variable transmission 500, a reduction gear 600, and a differential gear device 700 are provided. It is done.

  The output of engine 200 is input to continuously variable transmission 500 via torque converter 300 and forward / reverse clutch 400. The output of the continuously variable transmission 500 is transmitted to the reduction gear 600 and the differential gear device 700, and is distributed to the left and right drive wheels 800. Instead of the belt type continuously variable transmission 500, a chain type or toroidal type continuously variable transmission may be used.

  The torque converter 300 includes a pump impeller 302 connected to the crankshaft of the engine 200, a turbine impeller 306 connected to the forward / reverse clutch 400 via the turbine shaft 304, and the pump impeller 302 and the turbine impeller 306. And a lockup clutch 308 provided therebetween.

  The lockup clutch 308 is engaged or released according to the hydraulic pressure supplied from the outside. When the lockup clutch 308 is engaged, the pump impeller 302 and the turbine impeller 306 rotate integrally. The pump impeller 302 is provided with a mechanical oil pump 310 that generates hydraulic pressure.

  The forward / reverse clutch 400 is a power transmission clutch provided between the torque converter 300 and the continuously variable transmission 500. The forward / reverse clutch 400 is composed of a double pinion type planetary gear device. Turbine shaft 304 of torque converter 300 is connected to sun gear 402. The input shaft 502 of the continuously variable transmission 500 is connected to the carrier 404. Carrier 404 and sun gear 402 are connected via forward clutch 406. Ring gear 408 is fixed to the housing via reverse brake 410. The forward clutch 406 and the reverse brake 410 are engaged or released by hydraulic pressure supplied from outside.

  When the forward clutch 406 is engaged and the reverse brake 410 is released, the forward / reverse clutch 400 enters a forward power transmission state in which the forward drive force is transmitted to the continuously variable transmission 500. When the forward clutch 406 is disengaged and the reverse brake 410 is engaged, the forward / reverse clutch 400 enters a reverse power transmission state in which driving force in the reverse direction is transmitted to the continuously variable transmission 500. When the forward clutch 406 is released, the forward / reverse clutch 400 enters a neutral state in which power transmission is interrupted.

  The continuously variable transmission 500 includes a primary pulley 504 provided on the input shaft 502, a secondary pulley 508 provided on the output shaft 506, and a transmission belt 510 wound around these pulleys. Power is transmitted using frictional forces between the pulleys and the transmission belt 510.

  By controlling the hydraulic pressure of the hydraulic cylinder of the primary pulley 504, the groove width of each pulley changes. As a result, the engagement diameter of the transmission belt 510 is changed, and the gear ratio γ (= primary pulley rotation speed NIN / secondary pulley rotation speed NOUT) is continuously changed.

  FIG. 2 is a control block diagram showing an ECU (Electronic Control Unit) 8000 that controls each device of the vehicle 1 and devices connected to the ECU 8000.

  As shown in FIG. 2, the ECU 8000 includes an engine speed sensor 902, a turbine speed sensor 904, a vehicle speed sensor 906, a throttle opening sensor 908, a cooling water temperature sensor 910, an oil temperature sensor 912, an accelerator opening sensor 914, a foot A brake switch 916, a position sensor 918, a primary pulley rotation speed sensor 922, and a secondary pulley rotation speed sensor 924 are connected.

  Engine speed sensor 902 detects the rotational speed of engine 200 (hereinafter referred to as “engine speed NE”). The turbine rotation speed sensor 904 detects the rotation speed of the turbine shaft 304 (hereinafter referred to as “turbine rotation speed NT”). The vehicle speed sensor 906 detects the vehicle speed V. The throttle opening sensor 908 detects the opening degree θ (TH) of the electronic throttle valve. Cooling water temperature sensor 910 detects cooling water temperature T (W) of engine 200. The oil temperature sensor 912 detects the oil temperature T (C) of the continuously variable transmission 500 or the like. The accelerator opening sensor 914 detects an accelerator opening (amount of operation of the accelerator pedal by the user) A. The foot brake switch 916 detects whether or not the foot brake is operated. The position sensor 918 detects the position P (SH) of the shift lever 920 operated by the user. Primary pulley rotation speed sensor 922 detects the rotation speed of primary pulley 504 (hereinafter referred to as “primary pulley rotation speed NIN”). Secondary pulley rotation speed sensor 924 detects the rotation speed of secondary pulley 508 (hereinafter referred to as “secondary pulley rotation speed NOUT”). When the forward / reverse clutch 400 is in the forward power transmission state, the turbine rotational speed NT matches the primary pulley rotational speed NIN. The vehicle speed V becomes a value corresponding to the secondary pulley rotation speed NOUT. Therefore, when the vehicle is stopped and the forward clutch 406 is engaged, the turbine speed NT is zero. Each sensor transmits a signal representing the detection result to ECU 8000.

  ECU 8000 controls output of engine 200 by controlling electronic throttle valve 1000, fuel injection device 1100, ignition device 1200, and the like. ECU 8000 executes engagement control of lockup clutch 308 and forward / reverse clutch 400, shift control of continuously variable transmission 500, and the like by controlling hydraulic control circuit 2000.

  3 to 6 are diagrams schematically showing a configuration used for controlling the lock-up clutch 308 and the forward clutch 406 (forward / reverse clutch 400) in the hydraulic control circuit 2000.

  The hydraulic control circuit 2000 includes a pressure regulating valve 2010, a first on / off solenoid valve (hereinafter simply referred to as “first on / off valve”) S1, and a second on / off solenoid valve (hereinafter also simply referred to as “second on / off valve”) S2. , Linear solenoid valve RS, and switching valve 2020. The switching valve 2020 includes a first switching valve 2020A and a second switching valve 2020B.

  The linear solenoid valve RS adjusts and outputs the original pressure input from the outside to a hydraulic pressure corresponding to a command pressure from the ECU 8000 (hereinafter also referred to as “linear command pressure”). The output hydraulic pressure of the linear solenoid valve RS (hereinafter also referred to as “linear solenoid pressure”) is output to the switching valve 2020 (the first switching valve 2020A and the second switching valve 2020B).

  Both the first and second on / off valves S1 and S2 are controlled to be in either an on state in which hydraulic pressure is output or an off state in which no hydraulic pressure is output in accordance with a control signal from the ECU 8000. The output hydraulic pressures of the first and second on / off valves S1 and S2 are supplied to the pressure regulating valve 2010 and the switching valve 2020 (the first switching valve 2020A and the second switching valve 2020B).

  3 shows the hydraulic flow when S1 is on and S2 is on, FIG. 4 shows the hydraulic flow when S1 is off and S2 is off, and FIG. 5 shows S1 off and S2 is on. FIG. 6 shows the flow of hydraulic pressure when S1 is on and S2 is off.

  The pressure regulating valve 2010 regulates and outputs the line pressure that is the original pressure to a constant pressure. The value of the constant pressure output from the pressure regulating valve 2010 is changed according to whether or not the hydraulic pressure is input from the second on / off valve S2. When S2 is on, the constant pressure output from the pressure regulating valve 2010 is a relatively high value (see FIGS. 3 and 5). On the other hand, when S2 is off, the constant pressure output from the pressure regulating valve 2010 is a relatively low oil pressure (see FIGS. 4 and 6). The constant pressure output from the pressure regulating valve 2010 is supplied to the first switching valve 2020A.

  The switching valve 2020 switches the hydraulic pressure supplied to the lockup clutch (LUC) 308 and the forward clutch (FC) 406 according to the combination of hydraulic pressures input from the first and second on / off valves S1 and S2.

  When S1 is on and S2 is on, the switching valve 2020 is in the state shown in FIG. 3 (hereinafter referred to as “first state”). In this first state, the lockup clutch 308 is released because the hydraulic pressure of the lockup clutch 308 is discharged to the outside via the second switching valve 2020B. In other words, a predetermined release hydraulic pressure is supplied to the lockup clutch 308. On the other hand, the output hydraulic pressure of the pressure regulating valve 2010 (the hydraulic pressure obtained by regulating the line pressure to a constant pressure) is supplied to the forward clutch 406 via the first switching valve 2020A. Thereby, the forward clutch 406 is engaged.

  When S1 is off and S2 is off, the switching valve 2020 is in the state shown in FIG. The state of the switching valve 2020 at this time is the same state as the state shown in FIG. 3 described above, that is, the first state.

  As described above, when S1 is on and S2 is on, or when S1 is off and S2 is off, the switching valve 2020 supplies a predetermined release hydraulic pressure to the lockup clutch 308 and a predetermined engagement hydraulic pressure to the forward clutch 406. The first state is entered. Therefore, in the first state, the lockup clutch 308 is released and the forward clutch 406 is engaged.

  When S1 is off and S2 is on, the switching valve 2020 is in the state shown in FIG. 5 (hereinafter also referred to as “second state”). In the second state, the spool of the second switching valve 2020B is moved in the direction in which the spring is pressed (the direction indicated by the arrow α) with respect to the first state described above. As a result, the linear solenoid pressure is supplied to the lockup clutch 308. Therefore, the engagement state of the lockup clutch 308 is controlled by the linear solenoid pressure. On the other hand, as in the first state, the output hydraulic pressure of the pressure regulating valve 2010 is supplied to the forward clutch 406 via the first switching valve 2020A. Thereby, the forward clutch 406 is engaged.

  When S1 is on and S2 is off, the switching valve 2020 is in the state shown in FIG. 6 (hereinafter also referred to as “third state”). In the third state, the spool of the first switching valve 2020A is moved in the direction in which the spring is pressed (the direction indicated by the arrow β) with respect to the first state described above. As a result, the linear solenoid pressure is supplied to the forward clutch 406. Therefore, the engagement state of the forward clutch 406 is controlled by the linear solenoid pressure. On the other hand, the hydraulic pressure of the lockup clutch 308 is discharged to the outside through the second switching valve 2020B, as in the first state. Therefore, the lockup clutch 308 is released.

  ECU 8000 controls first and second on / off valves S1, S2 and linear solenoid valve RS according to a predetermined condition.

  FIG. 7 is a diagram summarizing the control modes executed by the ECU 8000. The ECU 8000 controls the state of the first and second on / off valves S1, S2 and the linear solenoid pressure in any one of the first to fourth control modes.

  In the first mode, the ECU 8000 outputs a control signal for turning S1 on and S2 on to the first and second on / off valves S1, S2. In this case, the switching valve 2020 is in the first state described above (see FIG. 3). In the first state, the linear solenoid pressure is not supplied to the lockup clutch 308 or the forward clutch 406. Therefore, in the first mode, ECU 8000 sets the linear command pressure to substantially zero.

  In the second mode, ECU 8000 outputs a control signal for turning S1 off and S2 off to first and second on / off valves S1 and S2. Also in this case, the switching valve 2020 is in the first state described above (see FIG. 4). In the second mode, as in the first mode, the ECU 8000 sets the linear command pressure to substantially zero.

  ECU 8000 sets the state of switching valve 2020 to the first state by setting the control mode to the first mode or the second mode during normal traveling. Therefore, during normal travel, the lockup clutch 308 is released and the forward clutch 406 is engaged. Further, the linear solenoid pressure is not supplied to either the lockup clutch 308 or the forward clutch 406.

  In the third mode, ECU 8000 outputs a control signal for turning S1 off and S2 on to first and second on / off valves S1 and S2. In this case, the switching valve 2020 is in the second state described above (see FIG. 5). In the second state, linear solenoid pressure is supplied to the lockup clutch 308. Therefore, when controlling the engagement state of the lockup clutch 308, the ECU 8000 switches to the third mode and adjusts the linear command pressure. In other words, the third mode is a control mode for performing lock-up clutch control.

  FIG. 8 is a diagram for explaining a mode of lock-up clutch (LUC) control. In FIG. 8, alternate long and short dash lines indicated by S1, S2, and RS indicate command signals (on / off control signals and linear command pressures) transmitted from the ECU 8000 to the valves, and solid lines indicate actual states (on / off states, Linear solenoid pressure). The same applies to FIGS. 9 and 11 described later.

  In the example shown in FIG. 8, the control mode is set to the second mode (S1 off and S2 off) before time t1 (before the lockup clutch control is started), and the state of the switching valve 2020 is the first state described above. It becomes. Therefore, a predetermined release hydraulic pressure is supplied to the lock-up clutch 308, and a hydraulic pressure obtained by adjusting the line pressure to a constant pressure (an output hydraulic pressure of the pressure adjustment valve 2010) is supplied to the forward clutch 406. At this time, since it is not necessary to increase the linear solenoid pressure, the linear command pressure is set to substantially zero.

  At time t1 when the lockup clutch control is started, ECU 8000 switches the control mode from the second mode to the third mode (S1 off and S2 on). As a result, the state of the switching valve 2020 is switched from the first state to the second state, so that the linear solenoid pressure is supplied to the lockup clutch 308. In this state, ECU 8000 adjusts the engagement state (engagement pressure) of lockup clutch 308 to a desired state by adjusting the linear command pressure. Note that the hydraulic pressure Pfc supplied to the forward clutch 406 is maintained at the hydraulic pressure obtained by adjusting the line pressure to a constant pressure even after the time t1.

  Returning to FIG. 7, in the fourth mode, the ECU 8000 outputs a control signal for turning S1 on and S2 off to the first and second on / off valves S1 and S2. In this case, the switching valve 2020 is in the above-described third state (see FIG. 6). In the third state, the linear solenoid pressure is supplied to the forward clutch 406. Therefore, when it is necessary to smoothly engage or disengage forward clutch 406, ECU 8000 controls the engaged state of forward clutch 406 by switching to the fourth mode and adjusting the linear command pressure.

  In the vehicle 1 having the above configuration, during normal traveling, the control mode is set to the first mode or the second mode as described above, so the forward clutch 406 is originally engaged. However, even during normal travel (during the first mode or the second mode), the forward clutch 406 may be released due to a failure of S1, S2, or the like. When shifting to the third mode in order to perform lockup clutch control in such a state, the hydraulic pressure Pfc supplied to the forward clutch 406 suddenly increases from substantially zero to a constant pressure, and the forward clutch 406 is suddenly engaged. Cause shock and belt slip.

  FIG. 9 is a diagram showing, as a reference, a control example corresponding to the prior art that starts lock-up clutch control in the event of an S1 on-failure (failure in which the first on-off valve S1 is stuck in the on state).

  In the example shown in FIG. 9, the control mode is set to the second mode (S1 off and S2 off) before time t2 (before the start of lockup clutch control). However, because of S1 on failure, S1 is not turned off but is fixed to S1 on. That is, the state of the switching valve 2020 should be the first state (S1, S2 = OFF, OFF, refer to the alternate long and short dash line) in terms of control, but actually the third state (S1, S2 = ON, OFF, see solid line). Therefore, linear solenoid pressure is supplied to the forward clutch 406 instead of the hydraulic pressure obtained by adjusting the line pressure to a constant pressure. Since the linear command pressure is set to substantially zero during the second mode, the hydraulic pressure Pfc supplied to the forward clutch 406 is substantially zero (minimum value MIN). Therefore, the forward clutch 406 is actually released.

  If the control mode is switched from the second mode to the third mode (S1 off and S2 on) in order to start the lock-up clutch control at time t2 in such a state, the state of the switching valve 2020 is controlled. Should be switched from the first state (S1, S2 = OFF, OFF) to the second state (S1, S2 = OFF, ON) (refer to the alternate long and short dash line). (S1, S2 = ON, OFF) is switched to the first state (S1, S2 = ON, ON) (see solid line). As a result, the hydraulic pressure Pfc supplied to the forward clutch 406 increases rapidly from substantially zero to a constant pressure, and the forward clutch 406 is suddenly engaged.

  In view of such a problem, ECU 8000 according to the present embodiment may cause an S1 ON failure when forward clutch 406 is released when lock-up clutch control is not being performed (during the third mode). Therefore, in order to avoid sudden engagement of the forward clutch 406, the transition to the lock-up clutch control (the transition to the third mode) is prohibited. Further, ECU 8000 attempts to engage forward clutch 406 by increasing the linear command pressure while prohibiting transition to lockup clutch control, and when it is detected that forward clutch 406 is actually engaged. Releases the lock-up clutch control prohibition and permits the transition to the lock-up clutch control.

  FIG. 10 is a flowchart showing a processing procedure for realizing the function of ECU 8000 described above.

  In step (hereinafter, step is abbreviated as “S”) 10, ECU 8000 determines whether lock-up clutch control is being performed or not. If lock-up clutch control is being performed (YES in S10), the process is terminated.

  If lock-up clutch control is not being performed (NO in S10), in other words, if the control mode is other than the third mode, ECU 8000 determines in S11 whether forward clutch 406 is released. For example, ECU 8000 determines that forward clutch 406 is released when the difference between turbine rotational speed NT and primary pulley rotational speed NIN exceeds a reference value.

  When forward clutch 406 is disengaged (YES in S11), ECU 8000 prohibits transition to lockup clutch control in S12. In addition, you may make it alert | report to a user using a display (video), a speaker (audio | voice), etc. that S1 ON failure may have arisen at this point.

  In subsequent S13, ECU 8000 increases the linear command pressure to increase the linear solenoid pressure.

  If forward clutch 406 is engaged (NO in S11), ECU 8000 permits transition to lockup clutch control in S14. At this time, when the forward clutch 406 is engaged by increasing the linear solenoid pressure in the process of S13 during the lock-up clutch control prohibition, the lock-up clutch control prohibition is released.

  FIG. 11 is a diagram illustrating a control example when the ECU 8000 executes lock-up clutch control when the S1 is on failure.

  Prior to time t11, the control mode is set to the second mode (S1 off and S2 off). However, because of S1 on failure, S1 is not turned off but is fixed to S1 on. As a result, the hydraulic pressure Pfc supplied to the forward clutch 406 becomes substantially zero, and the forward clutch 406 is released.

  When it is detected that forward clutch 406 is in the disengaged state at time t11, ECU 8000 prohibits transition to lockup clutch control. As a result, it is possible to prevent a shock from being suddenly shifted to the lock-up clutch control.

  Further, ECU 8000 starts increasing the linear command pressure after switching the control mode from the second mode to the fourth mode (S1 on and S2 off) at time t11. As a result, the linear solenoid pressure increases, and when it is detected that forward clutch 406 is engaged at time t12, ECU 8000 permits the transition to lockup clutch control.

  In the example shown in FIG. 11, ECU 8000 switches the control mode from the fourth mode to the first mode (S1 on and S2 on) at time t12. As a result, the state of the switching valve 2020 is switched to the first state even when the S1 ON failure occurs. Therefore, the hydraulic pressure for engaging the forward clutch 406 can be switched from the linear solenoid pressure to the hydraulic pressure adjusted to a constant line pressure.

  After switching to the first mode, the ECU 8000 considers the time lag until the state of the switching valve 2020 actually switches to the first state, and the ECU 8000 sets the linear command pressure near the maximum value until a predetermined period elapses from time t12. After that, the linear command pressure is returned to substantially zero.

  Thereafter, when the lockup clutch control start condition is satisfied at time t13, ECU 8000 switches the control mode from the first mode to the third mode and starts the lockup clutch control. At this time, the hydraulic pressure Pfc supplied to the forward clutch 406 does not change before and after time t13 and is maintained at a constant pressure, so that the problem of sudden engagement as shown in FIG. 9 does not occur.

  In the example shown in FIG. 11, after the time t13, the state of the switching valve 2020 is the second state (S1, S2 = OFF, ON, refer to the one-dot chain line) in terms of control, but due to the influence of the S1 ON failure. Actually, the first state is maintained. Therefore, in practice, the linear solenoid pressure is not supplied to the lockup clutch 308.

  As described above, ECU 8000 according to the present embodiment transitions to lock-up clutch control (third mode) when forward clutch 406 is released when lock-up clutch control is not being performed (third mode). ) Is prohibited. As a result, it is possible to avoid adverse effects caused by the S1 ON failure, specifically, shocks and belt slips caused by sudden engagement of the forward clutch 406 at the time of transition to the third mode.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  1 vehicle, 200 engine, 300 torque converter, 302 pump wheel, 304 turbine shaft, 306 turbine wheel, 308 lock-up clutch, 310 oil pump, 400 forward / reverse clutch, 402 sun gear, 404 carrier, 406 forward clutch, 408 ring gear , 410 reverse brake, 500 continuously variable transmission, 502 input shaft, 504 primary pulley, 506 output shaft, 508 secondary pulley, 510 transmission belt, 600 reduction gear, 700 differential gear device, 800 drive wheel, 902 engine speed sensor , 904 Turbine speed sensor, 906 Vehicle speed sensor, 908 Throttle opening sensor, 910 Cooling water temperature sensor, 912 sensor, 914 Accelerator opening sensor, 916 Foot brake switch H, 918 position sensor, 920 shift lever, 922 primary pulley rotation speed sensor, 924 secondary pulley rotation speed sensor, 1000 electronic throttle valve, 1100 fuel injection device, 1200 ignition device, 2000 hydraulic control circuit, 2010 pressure regulating valve, 2020 switching Valve, 2020A first switching valve, 2020B second switching valve, 8000 ECU, RS linear solenoid valve, S1 first on / off valve, S2 second on / off valve.

Claims (6)

A vehicle including a torque converter with a lock-up clutch and a power transmission clutch on a power transmission path from an engine to a drive wheel,
A linear solenoid valve that regulates and outputs the original pressure to a hydraulic pressure corresponding to the linear command pressure;
First and second on / off valves that output hydraulic pressure in the on state and do not output hydraulic pressure in the off state;
A switching valve that switches the hydraulic pressure supplied to the lockup clutch and the power transmission clutch according to a combination of hydraulic pressures input from the first and second on / off valves;
A control device for controlling the linear solenoid valve and the first and second on / off valves;
The switching valve supplies a predetermined release hydraulic pressure to the lockup clutch and a predetermined engagement hydraulic pressure to the power transmission clutch when both the first and second on / off valves are in an on state or an off state. When the first on / off valve is off and the second on / off valve is on, the output hydraulic pressure of the linear solenoid valve is supplied to the lock-up clutch and the power transmission clutch When the first on / off valve is on and the second on / off valve is off, the predetermined release hydraulic pressure is supplied to the lockup clutch. And it switches to the 3rd state which supplies the output oil pressure of the linear solenoid valve to the power transmission clutch,
The control device sets the switching valve to the first state by turning both the first and second on / off valves to an on state, and sets the linear command pressure to substantially zero, and the first mode A second mode in which both the second on-off valve are turned off to place the switching valve in the first state and the linear command pressure is made substantially zero; and the first on-off valve is turned off, and A third mode in which the second on / off valve is turned on to place the switching valve in the second state and adjust the linear command pressure to control the engagement state of the lock-up clutch. Controlling the first and second on / off valves in any of the control modes;
The control device restricts transition to the third mode when the power transmission clutch is released during a control mode other than the third mode.   2. The vehicle according to claim 1, wherein the control device executes an increase control for increasing an output hydraulic pressure of the linear solenoid valve while the transition to the third mode is restricted.   3. The control device according to claim 2, wherein when the power transmission clutch is engaged by the increase control, the control device releases the restriction on the transition to the third mode and allows the transition to the third mode. vehicle.   In addition to the first, second, and third modes, the plurality of control modes may be configured such that the first on / off valve is turned on and the second on / off valve is turned off to turn the switching valve on the third mode. The vehicle according to claim 1, further comprising a fourth mode for setting the state.   2. The vehicle according to claim 1, wherein the control device allows a transition to the third mode when the power transmission clutch is not released during a control mode other than the third mode. The vehicle further includes a continuously variable transmission,
The vehicle according to claim 1, wherein the power transmission clutch is a forward / reverse clutch provided between the torque converter and the continuously variable transmission.

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