JP2013164126A - Vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To specify a failure valve when an engine stall is caused.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 of 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 (RS) to the LUC and engaging the FC by turning off the S1 and turning on the S2. The ECU determines RS ON failure in the third mode when the engine stall is caused, determines S1 OFF failure in the first mode, and determines S2 OFF failure in the second mode.

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. Disclosed is a technique for determining which of the combinations of phenomena matches the combination of the abnormal phenomena actually occurring, and specifying that the solenoid valve corresponding to the combination determined to match is broken. ing.

JP 2009-257424 A

  However, Patent Document 1 does not disclose any configuration for specifying which control valve (solenoid valve) is malfunctioning when an engine stall occurs.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a vehicle including 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. Is to identify which control valve is malfunctioning when an engine stall occurs.

  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. Switch to the second state. The control device sets both the first and second on / off valves to the first state by setting both the first and second on / off valves to the on state, and sets both the first and second on / off valves to the off state. A second mode for setting the switching valve to the first state, and a third mode for setting the switching valve to the second state by setting the first on / off valve to the off state and turning the second on / off valve to the on state. The first and second on / off valves are controlled in any of a plurality of control modes including. The control device determines that the first on / off valve is abnormal when the engine stall occurs during the first mode, and determines that the second on / off valve is abnormal when the engine stall occurs during the second mode. When the engine stall occurs during the third mode, it is determined that the linear solenoid valve is abnormal.

  Preferably, the control device determines that the first on-off valve is an off-failure in which the first on-off valve is fixed in the off state when the engine stall occurs in response to the increase of the linear command pressure during the first mode, If the engine stall occurs in response to the increase of the linear command pressure during the second mode, it is determined that the second on / off valve is in an on failure in which the on / off valve is fixed to the on state.

  Preferably, the switching valve supplies a predetermined release hydraulic pressure to the lockup clutch and an output hydraulic pressure of the linear solenoid valve to the power transmission clutch when the first on / off valve is on and the second on / off valve is off. It switches to the 3rd state to supply. In addition to the first, second, and third modes, the plurality of control modes include a first control for setting the switching valve to the third state by turning on the first on / off valve and turning off the second on / off valve. 4 modes are further included. When the vehicle stops in the accelerator-off state during the first mode, the control device performs preparatory control for increasing the linear command pressure to a substantially maximum value in the first mode, and switches to the fourth mode after completion of the preparatory control. Neutral control is performed to release the power transmission clutch by controlling the command pressure. When the engine stall occurs in response to the execution of the preparation control during the first mode, the control device determines that the first on / off valve has an off failure.

  Preferably, when the power transmission clutch is changed from the released state to the engaged state, the control device performs engagement control for gradually increasing the linear command pressure in the fourth mode, and switches to the second mode after the end of the engagement control. End control for increasing the linear command pressure to a substantially maximum value is executed. The control device determines that the second on / off valve is in an on failure when an engine stall occurs in response to executing the end control during the second mode.

  Preferably, the control device has an abnormality in which the linear solenoid outputs a hydraulic pressure equal to or higher than the linear command pressure when an engine stall occurs until a predetermined time elapses after switching from the mode other than the third mode to the third mode. Is determined.

  Preferably, when the vehicle travels at a speed lower than a predetermined vehicle speed, the control device executes lockup control for controlling the engagement state of the lockup clutch by switching to the third mode and controlling the linear command pressure. The control device determines that it is abnormal for the linear solenoid to output a hydraulic pressure equal to or higher than the linear command pressure when an engine stall occurs before a predetermined time elapses from the start of the lockup control.

  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, in a vehicle having a torque converter with a lock-up clutch and a power transmission clutch on a power transmission path from the engine to the drive wheel, which control valve is broken when an engine stall occurs. Can be identified.

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 of 1st, 2nd on-off valve S1, S2. It is a functional block diagram of ECU. It is a figure for demonstrating the aspect of neutral control. It is a figure for demonstrating the aspect of forward clutch control. It is a figure for demonstrating the aspect of lockup clutch control. It is the figure which showed typically the state of each valve | bulb when neutral control was performed at the time of S1 off failure. It is the figure which showed typically the state of each valve | bulb when forward clutch control is performed at the time of S2 ON failure. It is the figure which showed typically the state of each valve when lockup clutch control is performed at the time of RS-on failure. It is the flowchart which illustrated the process sequence of ECU.

  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, 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 via the second switching valve 2020B. Therefore, the lockup clutch 308 is released.

  FIG. 7 is a diagram summarizing the control modes of the first and second on / off valves S1 and S2 executed by the ECU 8000. The ECU 8000 controls the first and second on / off valves S1, S2 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 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 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 fourth mode, ECU 8000 outputs a control signal for turning S1 on and S2 off to 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 vehicle 1 having the above-described configuration, when both the lock-up clutch 308 and the forward clutch 406 are simultaneously engaged, the engine speed NE, the turbine speed NT, and the primary pulley speed NIN are substantially equal. Therefore, for example, when both the lock-up clutch 308 and the forward clutch 406 are simultaneously engaged while the engine 200 is stopped (NE> 0 and NIN = NOUT = 0), the engine speed NE is increased. The engine is stalled by being pulled down to the primary pulley rotational speed NIN (= 0).

  Considering this point, ECU 8000 does not perform control to simultaneously engage both lockup clutch 308 and forward clutch 406 at least in the low vehicle speed region (the region where vehicle speed V is less than the predetermined value).

  However, when at least one of the first and second on / off valves S1 and S2 and the linear solenoid valve RS fails, both the lockup clutch 308 and the forward clutch 406 are simultaneously engaged in the low vehicle speed region, and the engine stall is caused. May occur. When such an engine stall occurs, it is desired to specify which one of the first and second on / off valves S1, S2 and the linear solenoid valve RS is malfunctioning.

  Therefore, ECU 8000 according to the present embodiment has a function of identifying a malfunctioning valve from the control mode when engine stall actually occurs. More specifically, ECU 8000 determines that first on / off valve S1 is abnormal when engine stall occurs during the first mode, and second on / off valve when engine stall occurs during second mode. It is determined that S2 is abnormal. If an engine stall occurs during the third mode, it is determined that the linear solenoid valve RS is abnormal. This is the most characteristic point of the present invention.

  FIG. 8 is a functional block diagram of the ECU 8000 relating to the identification of the failed valve. Each functional block shown in FIG. 8 may be realized by hardware or software.

ECU 8000 includes a control unit 8010 and a determination unit 8020.
First, the control unit 8010 will be described. The control unit 8010 controls the control mode and the linear solenoid pressure of the first and second on / off valves S1 and S2 in accordance with a predetermined condition.

  The control unit 8010 normally sets the switching valve 2020 to the first state by setting the control mode to the first mode or the second mode. As described above, in the first state, the lockup clutch 308 is released and the forward clutch 406 is engaged. In the first state, the linear solenoid pressure is not supplied to either the lockup clutch 308 or the forward clutch 406.

  When a condition that the vehicle 1 is stopped in the brake-on state (hereinafter also referred to as “neutral control start condition”) is established, the control unit 8010 performs “neutral control” that releases the forward clutch 406 using linear solenoid pressure. Run. At this time, the control unit 8010 switches the control mode from the first mode (or the second mode) to the fourth mode, supplies the linear solenoid pressure to the forward clutch 406, and gradually decreases (gradually decreases) the linear solenoid pressure. To release the forward clutch 406.

  FIG. 9 is a diagram for explaining a mode of neutral control. In FIG. 9, 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. 10 to 14 described later.

  During deceleration with the accelerator off (before time t1), since the control mode is the first mode, the lockup clutch 308 is released and the forward clutch 406 is engaged. Therefore, the turbine rotational speed NT substantially coincides with the primary pulley rotational speed NIN, while a speed difference between the turbine rotational speed NT and the engine rotational speed NE is allowed.

  When the neutral control start condition is satisfied at time t1, the control unit 8010 first maintains linearity while maintaining the first mode until time t2 when the predetermined time T1 elapses in preparation for switching to the fourth mode. Prepare control to increase solenoid pressure to near maximum value. When this preparation control is completed, the control unit 8010 switches the control mode from the first mode to the fourth mode to supply the linear solenoid pressure to the forward clutch 406, and gradually decreases the linear command pressure to change the forward clutch 406. Release smoothly. As a result, the turbine speed NT is increased to near the engine speed NE. A series of these controls is neutral control.

  Further, when the shift range is switched from the N (neutral) range to the D (drive) range by the shift operation by the user, the control unit 8010 uses the linear solenoid pressure to smoothly engage the forward clutch 406 “forward clutch control”. ”Is executed. At this time, the control unit 8010 switches the control mode from the first mode to the fourth mode, supplies the linear solenoid pressure to the forward clutch 406, and gradually increases (gradually increases) the linear solenoid pressure to smooth the forward clutch 406. Engage with.

  FIG. 10 is a diagram for explaining a mode of forward clutch control. Prior to time t3 when the shift range is the N range, the hydraulic pressure of the forward clutch 406 is discharged to the outside via a manual valve (not shown). Therefore, the forward clutch 406 is released.

  When the shift range is switched to the D range at time t3, the control unit 8010 smoothly engages the forward clutch 406 by switching the control mode from the first mode to the fourth mode and gradually increasing the linear solenoid pressure. The forward clutch engagement control to be combined is started. As the forward clutch engagement control is executed, the turbine rotational speed NT is gradually reduced to the primary pulley rotational speed NIN, but the engine speed NE is maintained because the lockup clutch 308 is released. Thereafter, the forward clutch engagement control is terminated at time t4 when the turbine rotational speed NT and the primary pulley rotational speed NIN substantially coincide.

  When the forward clutch engagement control is terminated, the control mode is switched from the fourth mode to the second mode. At this time, the hydraulic pressure supplied to the forward clutch 406 is switched from the linear solenoid pressure to a constant pressure (the state of the switching valve 2020 is switched from the third state to the first state), but considering the switching time lag due to the response delay of the hydraulic pressure Then, the control unit 8010 performs end control for increasing the linear solenoid pressure to near the maximum value from time t4 to time t5 when the predetermined time T2 elapses. Thereby, the entire forward clutch control is terminated.

  Further, the control unit 8010 executes “lock-up clutch control” that adjusts the engagement state of the lock-up clutch 308 using the linear solenoid pressure when the vehicle 1 travels in a region where the vehicle speed V is low. At this time, the control unit 8010 switches the control mode from the second mode to the third mode, supplies the linear solenoid pressure to the lockup clutch 308, and adjusts the engagement state of the lockup clutch 308 by the linear solenoid pressure.

  FIG. 11 is a diagram for explaining a mode of lock-up clutch control. When it is detected that the user depresses the accelerator pedal at time t7 and the vehicle starts running at time t8, the control unit 8010 switches the control mode from the second mode to the third mode and changes the vehicle speed. The linear solenoid pressure is gradually increased according to the increase. Thereby, the engagement state (engagement pressure) of the lock-up clutch 308 is appropriately adjusted according to the vehicle speed, and the power transmission efficiency is improved.

  Next, the determination unit 8020 will be described. The determination unit 8020 determines whether or not an engine stall has occurred from the detection result of the engine rotation speed NE or the like. Then, when an engine stall occurs, the determination unit 8020 identifies a failed valve from the control mode set by the control unit 8010 when the engine stall occurs.

  FIG. 12 is a diagram schematically showing the state of each valve when neutral control is executed at the time of S1 off failure (failure in which the first on / off valve S1 is stuck in the off state).

  Prior to time t11, since the vehicle is still running, the control mode is set to the first mode (S1 on and S2 on). However, due to the S1 off failure, S1 is not turned on but is fixed to S1 off. That is, the state of the switching valve 2020 should be the first state (S1, S2 = ON, ON, refer to the one-dot chain line) in terms of control, but actually the second state (S1, S2 = OFF, ON, see solid line). Accordingly, the forward clutch 406 is supplied with a hydraulic pressure adjusted to a constant line pressure, and the lockup clutch 308 is supplied with a linear solenoid pressure instead of a release hydraulic pressure (see FIG. 7).

  When the neutral control is started at time t11, as described above, the linear solenoid pressure becomes maximum while maintaining the first mode (actually in the second state) until time t12 when the predetermined time T1 elapses. Preparatory control that is increased to near the value is executed. In response to the execution of this preparation control, the lockup clutch 308 is engaged and the engine speed NE is reduced to the turbine speed NT (= 0), so that an engine stall occurs.

  Thus, a typical case where engine stall occurs in the first mode is a case where the linear solenoid pressure is increased by the preparation control in the S1 off-failure state. Therefore, the determination unit 8020 determines that an S1 off failure occurs when an engine stall occurs in the first mode. Note that, when an engine stall occurs in response to the execution of the preparation control in the first mode, it may be determined that the S1 off failure has occurred.

  FIG. 13 is a diagram schematically showing the state of each valve when the forward clutch control is executed at the time of S2 on failure (failure in which the second on / off valve S2 is stuck in the on state).

  Prior to time t13, the control mode is the first mode and the state of the switching valve 2020 is the first state, but the forward clutch 406 is released because the shift range is the N range.

  When the shift range is switched from the N range to the D range at time t13, the control mode is switched from the first mode to the fourth mode. However, because of S2 on failure, S2 is not turned off but is fixed to S2 on. That is, the state of the switching valve 2020 should be the third state (S1, S2 = ON, OFF, refer to the one-dot chain line) in terms of control, but actually the first state (S1, S2 = ON, ON, see solid line). Therefore, in actuality, at time t13 when switching to the D range, the forward clutch 406 is suddenly engaged by instantaneously supplying the forward clutch 406 with the hydraulic pressure adjusted to a constant line pressure. Thereby, the turbine rotational speed NT decreases rapidly.

  At time t14 when the turbine rotational speed NT decreases to the primary pulley rotational speed NIN, the forward clutch engagement control is terminated, and the control mode is switched from the fourth mode to the second mode. However, because of the S2 on failure, the state of the switching valve 2020 should be switched from the third state (S1, S2 = ON, OFF) to the first state (S1, S2 = OFF, OFF) in terms of control ( In practice, the one-dot chain line reference) is switched from the first state (S1, S2 = ON, ON) to the second state (S1, S2 = OFF, ON) (see solid line).

  After switching to the second mode (actually after the state of the switching valve 2020 is switched to the second state instead of the first state), as described above, until the time t15 when the predetermined period T2 elapses, the hydraulic pressure is increased. Considering the circuit switching time lag, end control is executed in which the linear solenoid pressure is increased to near the maximum value. In response to the execution of this end control, the lockup clutch 308 is engaged and the engine speed NE is reduced to the turbine speed NT (= 0), so that an engine stall occurs.

  As described above, a typical case where the engine stall occurs in the second mode is a case where the linear solenoid pressure is increased by the termination control in the S2 ON failure state. Therefore, the determination unit 8020 determines that an S2 on failure has occurred when an engine stall has occurred in the second mode. It should be noted that when the engine stall occurs in response to the execution of the end control in the second mode, it may be determined that the S2 on failure has occurred.

  FIG. 14 schematically shows the state of each valve when lock-up clutch control is executed in the event of an RS-on failure (a failure in which the linear solenoid valve RS is fixed in a state in which the maximum hydraulic pressure is output regardless of the linear command pressure). FIG.

  Before time t17 when the vehicle is stopped, the control mode is the second mode, and the state of the switching valve 2020 is the first state. Therefore, the linear solenoid pressure is not supplied to the lock-up clutch 308 or the forward clutch 406.

  When the user depresses the accelerator pedal at time t17, the vehicle 1 starts to travel. When it is detected that the vehicle 1 starts running at time t18, lockup clutch control is started, and the control mode is switched from the second mode to the third mode. Thereby, since the switching valve 2020 is switched to the second state, the forward clutch 406 is engaged and the linear solenoid pressure is supplied to the lockup clutch 308.

  After switching to the third mode, the linear solenoid pressure is gradually increased according to the increase in the vehicle speed (see the alternate long and short dash line). However, at time t18 when the mode is switched to the third mode due to an RS ON failure, the linear solenoid pressure has already reached the maximum hydraulic pressure (see solid line). Therefore, the lockup clutch 308 is suddenly engaged at time t18 when switching to the third mode. Due to this influence, the engine speed NE is suddenly reduced to the turbine speed NT (= 0), so that an engine stall occurs.

  Thus, a typical case where the engine stall occurs in the third mode is a case where the lockup clutch control is started in the RS-on failure state. Accordingly, the determination unit 8020 determines that an RS-on failure has occurred when an engine stall occurs in the third mode, more specifically, when an engine stall occurs within a predetermined time from the start of lockup clutch control.

  Note that the determination unit 8020 notifies the user of the determination result using a display (video), a speaker (sound), or the like.

  FIG. 15 is a flowchart illustrating a processing procedure for realizing the functions of the ECU 8000 described above. This flowchart is repeatedly executed at a predetermined cycle during the operation of the ECU 8000.

  In step (hereinafter, step is abbreviated as “S”) 10, ECU 8000 determines whether or not an engine stall has occurred from the detection result of engine speed NE. If an engine stall has not occurred (NO in S10), the process ends.

  If an engine stall has occurred (YES in S10), ECU 8000 determines in S20 whether it is within a predetermined time from the start of lockup clutch control. As described above, it may be determined whether or not the control mode is the third mode in this process.

  If it is within a predetermined time from the start of lockup clutch control (YES in S20), ECU 8000 determines in S30 that there is an RS-on failure. If it is not within the predetermined time from the start of lockup clutch control (NO in S20), ECU 8000 determines in S40 whether the control mode is the first mode.

  When in the first mode (YES in S40), ECU 8000 determines in S50 that there is an S1 off failure. If not in the first mode (NO in S40), ECU 8000 determines in S60 whether or not the control mode is the second mode.

  When in the second mode (YES in S60), ECU 8000 determines in S70 that there is an S2 off failure. If not in the second mode (NO in S60), the process is terminated.

  In addition, although the example which determines in order of S20, S40, S60 is shown by FIG. 15, these determination orders are not specifically limited.

  As described above, ECU 8000 according to the present embodiment identifies a malfunctioning valve from the control mode when engine stall has occurred. Specifically, ECU 8000 determines that S1 is abnormal (S1 off failure) when engine stall occurs during the first mode, and S2 abnormality (S2 on) when engine stall occurs during second mode. If the engine stall occurs during the third mode, it is determined that there is an RS abnormality (RS on failure). In this way, even in the event of the same engine stall, it is possible to quickly identify which valve is abnormal by acquiring what control mode was being controlled when the engine stall occurred. Can do.

  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, 8010 control unit, 8020 determination unit, RS linear solenoid valve, S1 first on / off valve, S2 second on / off valve.

Claims (7)

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 To the second state in which the predetermined engagement hydraulic pressure is supplied to
The control device sets both the first and second on / off valves to the first mode by turning both the first and second on / off valves on, and the first mode and the second on / off valve. A second mode for setting the switching valve to the first state by turning it off; and setting the switching valve to the first state by turning the first on / off valve off and turning the second on / off valve on. And controlling the first and second on / off valves in any one of a plurality of control modes including a third mode for setting the second state,
The control device determines that the first on / off valve is abnormal when an engine stall occurs during the first mode, and the second on / off valve when the engine stall occurs during the second mode. Is determined to be abnormal, and if the engine stall occurs during the third mode, the linear solenoid valve is determined to be abnormal.   When the engine stall occurs in response to the increase of the linear command pressure during the first mode, the control device determines that the first on / off valve is an off failure in which the first on / off valve is fixed in an off state. 2. When the engine stall occurs in response to the increase of the linear command pressure during the second mode, it is determined that the second on / off valve is in an on-failure state in which the second on / off valve is fixed to an on state. Vehicle described in. The switching valve supplies the predetermined release hydraulic pressure to the lockup clutch and the linear solenoid valve to the power transmission clutch when the first on / off valve is on and the second on / off valve is off. Switch to the third state to supply the output hydraulic pressure of
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. And further includes a fourth mode for entering a state,
When the vehicle stops in the accelerator-off state during the first mode, the control device performs preparatory control for increasing the linear command pressure to a substantially maximum value in the first mode, and after the preparatory control ends, Performing neutral control to release the power transmission clutch by switching to the fourth mode and controlling the linear command pressure;
3. The control device according to claim 2, wherein the control device determines that the first on-off valve is the off-failure when the engine stall occurs in response to the execution of the preparation control during the first mode. vehicle. The control device performs engagement control for gradually increasing the linear command pressure in the fourth mode when the power transmission clutch is changed from the released state to the engaged state, and after the engagement control is finished, the second mode Execute end control to increase the linear command pressure to a substantially maximum value by switching to
4. The control device according to claim 3, wherein the control device determines that the second on / off valve is the on-failure when the engine stall occurs in response to the execution of the end control during the second mode. 5. vehicle.   When the engine stall occurs before a predetermined time elapses after the control device switches from the mode other than the third mode to the third mode, the linear solenoid outputs a hydraulic pressure equal to or higher than the linear command pressure. The vehicle according to claim 1, wherein the vehicle is determined to be abnormal. The control device executes lock-up control for controlling an engagement state of the lock-up clutch by switching to the third mode and controlling the linear command pressure when the vehicle travels below a predetermined vehicle speed. ,
The control device determines that the linear solenoid is abnormal to output a hydraulic pressure equal to or higher than the linear command pressure when the engine stall occurs before the predetermined time elapses from the start of the lockup control. Item 6. The vehicle according to Item 5. 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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