JP2009133434A - Controller of vehicular lock-up clutch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a failure of a valve for controlling the engagement and a release of an L/U clutch to be determined properly without causing the stop of revolutions of a driving force source even during the stop of a vehicle before starting. <P>SOLUTION: When an automatic transmission 10 is put into an interrupted state by selecting "P" or "N", a command is outputted to change over an L/U relay valve 102 to an ON side communication state (S4). A failure that an L/U control valve 104 is in an ON failure is determined based on a difference ΔN(=N<SB>E</SB>-N<SB>T</SB>) between the input-side and output-side rotational speeds of a torque converter 32 when it becomes ΔN<N1, that is, when it is presumed that the L/U clutch 28 is put into an engaged state (S6). When the vehicle is stopped in the driving range, the L/U relay valve 102 is changed over to the ON side communication state to prohibit the execution of a lost drive countermeasure that inhibits air-mixed hydraulic oil from flowing into the torque converter 32 (S7). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a control device for a lockup clutch for a vehicle, and more particularly to an improvement in a technique for determining a valve failure (failure) for controlling engagement / release of a lockup clutch.

  (a) It is provided in a fluid type power transmission device to which power is transmitted from a driving force source, and is engaged based on a differential pressure between the hydraulic pressure in the engagement side oil chamber and the hydraulic pressure in the release side oil chamber. A lockup clutch that directly connects the input side and the output side of the fluid power transmission device; and (b) supplying hydraulic oil to the engagement side oil chamber and connecting the release side oil chamber to the first discharge oil passage. A first valve that is switched between an ON state in which the hydraulic oil is supplied to the release-side oil chamber and an OFF state in which the engagement-side oil chamber is connected to the second discharge oil passage, and (c) the first discharge. A second valve that is switched between an ON state in which the hydraulic oil in the oil passage is discharged and an OFF state in which the hydraulic oil is supplied to the first discharge oil passage; (d) the first valve and the Engage the lock-up clutch by turning on the second valves. A control device for a vehicle lockup clutch that releases the lockup clutch when the first valve is turned off is known. The device described in Patent Document 1 is an example, and the clutch valve 108 corresponds to a first valve, the slip control solenoid valve 110 corresponds to a second valve, and a torque converter is used as a fluid type power transmission device. .

Further, Patent Document 2 outputs a command for switching ON (engaged) and OFF (released) of the lockup clutch during steady running at a predetermined vehicle speed or higher, and the input side rotational speed at that time, that is, the rotational speed of the driving force source. A technique for diagnosing a failure of a lockup mechanism such as the first valve or the second valve based on the change has been proposed.
JP 2007-247813 A JP-A-7-167286

  By the way, when the vehicle is stopped in a driving range such as the D range at the start of the engine when the temperature of the hydraulic oil is low, the viscosity of the hydraulic oil becomes high and the return to the oil pan is delayed at a low oil temperature. For this reason, the oil level (oil level) of the oil pan is lowered, and hydraulic oil mixed with bubbles due to air suction may be supplied to the fluid power transmission device. When the vehicle is stopped, the lockup clutch is released, and the first valve is turned off, so that the hydraulic oil is discharged from the second discharge oil passage to an oil cooler or the like. Since the rotation of the vehicle (such as a turbine impeller) is stopped, bubbles are likely to stop and accumulate in the fluid power transmission device. That is, when rotating, the hydraulic oil is pressed toward the outer peripheral side by centrifugal force, whereby bubbles gather at the center side, and the hydraulic oil is supplied to the release-side oil chamber, whereby the second portion provided on the rotation shaft of the central portion. Although the hydraulic oil mixed with air bubbles is discharged into the oil discharge passage, the air bubbles are likely to adhere to the output-side rotary impeller and the like when the rotation is stopped. If a large amount of such bubbles are accumulated in the fluid power transmission device due to a long stoppage, the transmission torque of the fluid power transmission device cannot be sufficiently obtained due to the presence of the bubbles at the start of the vehicle. There may be a lost drive whose driving performance is impaired.

  Although this is not yet known as a countermeasure, the second valve is turned off when the vehicle is stopped when a command is issued to turn off both the first valve and the second valve and the lockup clutch is released. A command to switch the first valve to the ON state while maintaining the flow rate of the hydraulic fluid to both the engagement-side oil chamber and the release-side oil chamber to inhibit the flow of the hydraulic oil, It can be considered that mixed hydraulic oil is prevented from flowing into the fluid power transmission device.

  However, at this time, if the second valve is fixed in the ON state due to an electrical system failure (disconnection or short circuit), a valve stick, etc., the lock-up clutch is engaged by switching the first valve to the ON state. The driving force source such as the engine stops rotating. For this reason, it is desired to diagnose in advance whether or not the second valve is ON-failed, and when it is ON-failed, it is desirable to prohibit the implementation of the lost drive countermeasure. The diagnosis technique described in is for diagnosing based on the change in rotational speed of the driving force source when the lock-up clutch is switched on and off, so that the diagnosis can be performed only during steady running at a predetermined vehicle speed or higher. It is not enough to take measures against lost drive when the vehicle is stopped in the driving range such as the D range before starting the vehicle.

  The present invention has been made against the background of the above circumstances, and the purpose of the present invention is to drive the valve fail judgment for controlling the engagement and release of the lockup clutch at the time of failure even when the vehicle is stopped before starting. It is to be able to perform appropriately without causing the rotation stop of the force source.

  In order to achieve such an object, the first invention is provided in (a) a fluid-type power transmission device to which power is transmitted from a driving force source, and includes a hydraulic pressure in an engagement side oil chamber and a hydraulic pressure in a release side oil chamber. A lockup clutch that directly connects the input side and the output side of the fluid power transmission device by being engaged based on the differential pressure; and (b) supplying hydraulic oil to the engagement side oil chamber and Switching between the ON state in which the release side oil chamber is connected to the first discharge oil passage and the OFF state in which hydraulic oil is supplied to the release side oil chamber and the engagement side oil chamber is connected to the second discharge oil passage. A first valve that is switched, and (c) a second valve that is switched between an ON state in which the hydraulic oil in the first discharge oil passage is discharged and an OFF state in which the hydraulic oil is supplied to the first discharge oil passage. (D) both the first valve and the second valve are turned on. In the vehicle lockup clutch control device that engages the lockup clutch and releases the lockup clutch when the first valve is turned off, (e) the first valve and the second valve A command to turn on one of the valves and turn off the other is output to change the output side rotational speed of the fluid-type power transmission device or to rotate the difference between the output side rotational speed and the input side rotational speed. And a failure determination means for determining the failure of the first valve or the second valve.

  According to a second aspect of the present invention, in the control device for a lockup clutch for a vehicle according to the first aspect of the invention, (a) it is possible to switch between a power transmission state and a cutoff state between the fluid type power transmission device and the drive wheels. An interrupting mechanism is provided, and (b) the fail determining means performs the fail determination when the interrupting mechanism is in a shut-off state.

  According to a third aspect of the invention, in the control device for a lockup clutch for a vehicle according to the first or second aspect of the invention, the fail determining means performs the fail determination when the temperature of the hydraulic oil is equal to or lower than a predetermined value. And

  4th invention is the control apparatus of the lockup clutch for vehicles in any one of 1st invention-3rd invention, (a) When the vehicle stops, the said 1st valve is made into an ON state, and said 2nd valve is made into an OFF state. (B) The fail determination, while having an air mixing countermeasure means for outputting a command and blocking the flow of the hydraulic oil so that the hydraulic oil is supplied to both the engagement side oil chamber and the release side oil chamber The means outputs a command to turn on the first valve and turn off the second valve, change the output side rotational speed of the fluid power transmission device, or the output side rotational speed and the input side rotational speed. And when it is estimated that the lock-up clutch is engaged based on the differential rotation of the second valve, it is determined that the second valve is ON-failed. (C) Based on judgment result , And determines whether to execute a control by the air intrusion protection means.

  In such a control device for a lockup clutch for a vehicle, the output of the fluid type power transmission device is output by outputting a command to turn on one of the first valve and the second valve and turn off the other. Based on the change in the side rotational speed or the differential rotation between the output side rotational speed and the input side rotational speed, the first valve or the second valve fails. That is, when a command to turn the first valve on and the second valve off is output, if both valves are normal, hydraulic oil is supplied to both the engagement side oil chamber and the release side oil chamber. While the lock-up clutch is released, when the second valve is in an on-fail state, the hydraulic oil in the release-side oil chamber is discharged from the first discharge oil passage through the second valve, and the lock-up clutch is released. When the lockup clutch is estimated to be engaged based on the change in the output side rotational speed of the fluid power transmission device or the differential rotation between the output side rotational speed and the input side rotational speed. It can be determined that the second valve is ON-failed. Also, when a command to turn on the second valve and turn off the first valve is output, if both valves are normal, hydraulic oil is supplied to the release side oil chamber and the engagement side oil chamber is activated. When the oil is discharged from the second discharge oil passage, the lock-up clutch is released. On the other hand, when the first valve is ON-failed, the hydraulic oil is supplied to the engagement side oil chamber. At the same time, since the hydraulic oil in the release side oil chamber is discharged from the first discharge oil passage through the second valve and the lockup clutch is engaged, the change in the output side rotational speed of the fluid type power transmission device or the output side rotation thereof If it is estimated that the lockup clutch is engaged based on the differential rotation between the speed and the input side rotational speed, it can be determined that the first valve is in an on-fail state.

  Here, in the present invention, the failure determination is performed based on the change in the output side rotational speed of the fluid type power transmission device or the differential rotation between the output side rotational speed and the input side rotational speed. It is not always necessary to change the side rotational speed, that is, the rotational speed of the driving force source. By stopping the power transmission between the driving wheels not only when the vehicle is running but also when the vehicle is stopped, It is possible to appropriately perform the failure determination without causing a stop. As a result, for example, as in the fourth aspect of the invention, it is determined whether or not the second valve is ON-failed, and when it is ON-failed, the execution of the control by the air mixing countermeasure means is prohibited. It can be avoided that the driving force source stops rotating due to the ON failure due to the control by the air mixing countermeasure means.

  The second invention is a case where an intermittent mechanism is provided between the hydrodynamic power transmission device and the drive wheel, and the fail determination means performs a fail determination when the intermittent mechanism is in a cutoff state. Even when the first valve or the second valve is in the ON failure state and the lockup clutch is engaged at the time of the failure determination, it is possible to appropriately determine the ON failure of those valves without causing the drive force source to stop rotating. it can.

  In the third invention, since the failure determination is performed when the oil temperature of the hydraulic oil is equal to or lower than the predetermined value, the control by the air mixing countermeasure means is performed based on the determination result related to the failure determination of the second valve as in the fourth invention. In the case of determining whether or not, it is possible to avoid useless signal processing in which the failure determination is performed until the oil temperature is relatively high and there is no possibility of the hydraulic oil mixed in.

  According to a fourth aspect of the present invention, when the vehicle is stopped, a command to turn on the first valve and turn off the second valve is output, and hydraulic oil is supplied to both the engagement-side oil chamber and the release-side oil chamber. In the case where there is an air mixing countermeasure means that inhibits the flow of the hydraulic fluid and suppresses the flow of the hydraulic fluid, the hydraulic fluid flows into the fluid power transmission device for a long time. When the vehicle stops, a large amount of bubbles are accumulated, and when the vehicle starts, the transmission torque of the fluid power transmission device cannot be sufficiently obtained due to the presence of the bubbles, and the occurrence of lost drive, in which the start drive performance is impaired, is suppressed. In this case, if the second valve is ON-failed, the hydraulic oil in the release side oil chamber is discharged from the first discharge oil passage through the second valve, the lock-up clutch is engaged, and the driving force source is Although the rotation stops, it is determined whether or not the second valve is ON-failed by the fail determination means, and whether or not the control by the air mixing countermeasure means is determined based on the determination result. Therefore, if the control by the air mixing countermeasure means is prohibited during the ON failure of the second valve, the driving force source is generated along with the execution of the control by the air mixing countermeasure means due to the ON failure of the second valve. Is prevented from stopping rotating.

  For example, an internal combustion engine that generates power by combustion of fuel, such as a diesel engine or a gasoline engine, is preferably used as the fluid power transmission device. Various driving force sources such as an electric motor or a combination of an electric motor and an internal combustion engine can be employed. The intermittent mechanism can be switched between a power transmission state and a cut-off state, and may be a simple clutch or the like, but a planetary gear type stepped transmission having a neutral that cuts off power transmission, or forward / reverse switching A device or the like is preferably used. Apart from the intermittent mechanism, a continuously variable transmission such as a belt type may be provided. A torque converter is preferably used as the fluid power transmission device, but a fluid coupling or the like can also be employed. Note that the intermittent mechanism is not necessarily required when the valve is switched during the vehicle traveling to perform the fail determination.

  The first valve is configured such that, for example, the spool is selectively moved to two positions and switched between the ON state and the OFF state depending on whether or not a predetermined signal oil pressure is supplied from a solenoid valve, for example. Various modes are possible, such as the spool can be moved directly by a solenoid. In the ON state, for example, a line oil passage to which a predetermined line oil pressure is supplied is connected to the engagement side oil chamber, and the line oil pressure is supplied to the engagement side oil chamber. The line is connected to the release-side oil chamber and the line hydraulic pressure is supplied to the release-side oil chamber. Although the first discharge oil passage is connected to the second valve, the second discharge oil passage may be drained to the oil pan or the like as it is, but it is cooled by introducing the hydraulic oil into the oil cooler. It is desirable to do so.

  The second valve is configured to connect the second discharge oil passage to the drain oil passage in the ON state and connect the line oil passage to the second discharge oil passage in the OFF state to supply hydraulic oil. However, for example, when the hydraulic pressure of the signal hydraulic pressure supplied from the linear solenoid valve is continuously changed, the position of the spool is continuously changed between the ON state and the OFF state. By continuously changing the communication state (flow cross-sectional area, etc.) between the oil passage, the drain oil passage, and the line oil passage, the hydraulic pressure in the first discharge oil passage, that is, the hydraulic pressure in the release-side oil chamber can be adjusted. It can also be configured. In that case, the differential pressure between the oil pressure in the engagement side oil chamber and the release side oil chamber changes continuously according to the oil pressure in the release side oil chamber, and the lockup clutch can be engaged in a predetermined slip state. it can.

  The fail determination means is estimated, for example, that the lockup clutch is engaged based on a change in the output side rotational speed of the fluid type power transmission device or a differential rotation between the output side rotational speed and the input side rotational speed. In this case, the first valve or the second valve is configured to determine that it has failed. Specifically, when performing a fail determination when the lockup clutch is released when the vehicle is stopped, if the output side rotational speed increases by a predetermined rotational speed or more, the output side rotational speed becomes the input side rotational speed. When the differential rotation between the output side rotational speed and the input side rotational speed becomes less than a predetermined value, when the differential rotation decreases by a predetermined constant rotational speed, etc. It can be determined as an ON failure. It is also possible to make a fail judgment while the vehicle is running, in which case it depends on whether the lock-up clutch is engaged or disengaged. When the differential rotation between the side rotational speed and the input side rotational speed remains below a predetermined value, it can be determined as an ON failure. Also, at the time of release, when the differential rotation between the output-side rotational speed and the input-side rotational speed is less than a predetermined value, or when the differential rotation is decreased by a predetermined constant rotational speed, etc., it is determined as ON failure. it can. When fail determination is performed when the lockup clutch is released including when the vehicle is stopped, the driver's output request amount such as the accelerator operation amount is constant, that is, the operating state of the driving force source is It is desirable to perform in a substantially constant state, and it is desirable to prohibit the fail determination when the operating state of the driving force source changes.

  For example, N (neutral) or P (parking) in which the interrupting mechanism is shut off is selected by the driving state selecting means, and the oil temperature of the hydraulic oil may cause a problem of air suction. When a certain predetermined value T1 or less, for example, 0 ° C. or less, and the differential rotation between the input side rotational speed and the output side rotational speed of the fluid type power transmission device is a predetermined value N1 or more, the valve is switched to perform the fail determination. Configured. In general, when the oil temperature is low such that air suction becomes a problem, the differential rotation is about 100 to 200 rpm due to the rotational resistance of an automatic transmission or the like due to agitation resistance or the like because the viscosity of the hydraulic oil is high. N1 is smaller than the differential rotation (100 to 200 rpm) and larger than the differential rotation (for example, about 25 rpm) at about 80 ° C. where there is no fear of air suction, and is set to about 50 rpm, for example. . As a result, only when there is a possibility of lost drive, the valve failure determination is performed reliably.

  Even when the driving range such as D (drive) in which the intermittent mechanism is in the power transmission state is selected by the driving state selection means, the input clutch, the brake, etc. are forcibly released to be in the shut-off state, and the fail determination is performed. It is also possible. Even when the lockup clutch is engaged, it is possible to make a fail determination while the drive power source does not stop rotating. In this case, a drive range such as D (drive) is selected by the drive state selection means. In addition, it is possible to carry out a fail determination while maintaining the power transmission state.

  Although the fourth aspect of the invention is provided with the air mixing countermeasure means, it can be applied to a vehicle that does not have the air mixing countermeasure means when implementing other inventions. The air contamination countermeasure means of the fourth aspect of the invention is, for example, a power transmission state in which a driving range such as the D range is selected, when the vehicle speed is approximately 0, and the oil temperature of the hydraulic oil becomes a problem of air suction. Although control is performed to prevent air contamination when the value is equal to or less than a predetermined value, it can also be performed when power transmission is interrupted when P (parking) or N (neutral) is selected.

  When deciding whether or not to implement control by the air mixing countermeasure means according to the result of the fail judgment by the fail judgment means, the fail judgment is performed only when selecting P or N immediately after starting the driving force source such as an engine, Once the D range or the like is selected and the vehicle has traveled, the fail determination may be stopped.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a skeleton diagram showing a schematic configuration of a vehicle drive device 8 to which the present invention is preferably applied. The vehicle 30 is preferably used for an FF vehicle mounted in the left-right direction (horizontal orientation) of the vehicle. Is transmitted from the torque converter 32 and the automatic transmission 10 to the pair of drive wheels 40 via the differential gear unit 34 and the pair of axles 38 shown in FIG. The engine 30 is a driving force source, and is constituted by an internal combustion engine such as a gasoline engine or a diesel engine. The torque converter 32 is a fluid power transmission device, and an input / output member, that is, a pump impeller 32p connected to the crankshaft of the engine 30 and a turbine impeller 32t connected to the input shaft 22 of the automatic transmission 10 are integrated. Or a lock-up clutch 28 that is connected in a predetermined relative rotational state.

  The automatic transmission 10 includes, in a transmission case 26 as a non-rotating member attached to a vehicle body, a first transmission unit 14 mainly composed of a single pinion type first planetary gear unit 12 and a double pinion type first gear unit. The second planetary gear device 16 and the single pinion type third planetary gear device 18 are used as a main component and have a second transmission 20 configured in a Ravigneaux type on a coaxial line (on a common axis C), and an input shaft 22 Are rotated and output from the output gear 24. The output gear 24 corresponds to an output member of the automatic transmission 10 and is a differential drive gear that meshes with a differential driven gear (large-diameter gear) 36 to transmit power to the differential gear device 34 shown in FIG. It is functioning. The automatic transmission 10 and the torque converter 32 are substantially symmetrical with respect to the center line (axial center) C, and the lower half of the center line C is omitted in the skeleton diagram of FIG. .

  The automatic transmission 10 includes clutches C1 and C2 and brakes B1 to B3 (hereinafter simply referred to as a clutch C and a brake B unless otherwise distinguished), and each of the first transmission unit 14 and the second transmission unit 20 is provided. As shown in FIG. 2, the first speed gear stage “1st” to the sixth speed gear stage are switched by switching the connection relationship and the fixed elements of the rotating elements (sun gears S1 to S3, carriers CA1 to CA3, ring gears R1 to R3). Six forward gear stages “6th” and one reverse gear stage “R” are established. That is, the engagement of the clutch C1 and the brake B2 changes the first speed gear, the engagement of the clutch C1 and the brake B1, the second speed gear, and the engagement of the clutch C1 and the brake B3, the third speed gear. The fourth gear is set by engagement of the clutch C1 and the clutch C2, the fifth gear is set by engagement of the clutch C2 and the brake B3, and the sixth gear is set by engagement of the clutch C2 and the brake B1. Each gear stage is established. Further, the reverse gear stage is established by the engagement of the brake B2 and the brake B3, and all of the clutches C1, C2 and the brakes B1 to B3 are released, so that a neutral state in which power transmission is interrupted is established. It is configured. FIG. 2 is an engagement operation table for explaining the operation states of the plurality of gear stages and the clutches C1 and C2 and the brakes B1 to B3 when each gear stage is established. “O” represents engagement. . The automatic transmission 10 corresponds to an intermittent mechanism that can be switched between a power transmission state and a cutoff state.

  The clutch C and the brake B are hydraulic friction engagement devices that are engaged and controlled by hydraulic actuators such as multi-plate clutches and brakes, and are linear solenoids as electromagnetic valve devices in the hydraulic control device 100 (see FIG. 3). Engagement, de-excitation, and current control control the valves SLC1, SLC2, SLB1, SLB2, and SLB3 to switch between engaged and disengaged states and control transient oil pressures during engagement and disengagement.

  FIG. 3 is a block diagram illustrating a main part of an electrical control system provided in the vehicle for controlling the automatic transmission 10 of FIG. The electronic control unit 90 includes, for example, a so-called microcomputer having a CPU, a RAM, a ROM, an input / output interface, and the like. The CPU uses a temporary storage function of the RAM and follows a program stored in the ROM in advance. By performing signal processing, output control of the engine 30, shift control of the automatic transmission 10, engagement and release control of the lockup clutch 28, and the like are executed. It is configured separately for control purposes.

3, the intake air of the engine rotational speed sensor 58, the engine 30 for detecting the rotational speed N _E of the accelerator operation amount sensor 52, an engine 30 for detecting an operation amount (accelerator opening) Acc of an accelerator pedal 50 an intake air amount sensor 60, the intake air temperature sensor 62 for detecting the temperature T _a of intake air, a throttle valve opening sensor 64 for detecting an opening theta _TH of an electronic throttle valve for detecting the amount Q, a vehicle speed sensor 66 for detecting a vehicle speed V (corresponding to the rotational speed N _OUT of the output gear 24), the cooling water temperature sensor 68 for detecting the cooling water temperature T _W of the engine 30, operation of the foot brake pedal 69 is a service brake a brake switch 70 for detecting the presence of a lever position (operating position) of the shift lever 72 as a shift operation member for detecting the P _SH Because of the lever position sensor 74, a turbine rotational speed N _T or input axis 22 of the rotational speed N _IN the turbine rotational speed sensor 76 for detecting the AT oil temperature T _OIL is a temperature of the hydraulic oil in the hydraulic control device 100 An AT oil temperature sensor 78 for detection is provided, and the accelerator operation amount (accelerator opening degree) Acc, engine rotational speed N _E , intake air amount Q, intake air temperature T are provided from these sensors and switches. _A , throttle valve opening θ _TH , vehicle speed V, output rotation speed N _{O UT} , engine cooling water temperature T _W , presence or absence of brake operation, shift lever 72 lever position P _SH , turbine rotation speed N _T (= input shaft rotation speed) N _IN ), AT oil temperature T _{OIL and the} like are supplied to the electronic control unit 90. The accelerator operation amount Acc corresponds to the driver's requested output amount.

  The shift lever 72 functions as drive state selection means for selecting the operating state of the automatic transmission 10, and for example, a “P” position for parking, an “N” position for interrupting power transmission, and a “D” for forward travel. The position is selectively moved to the “R” position, etc. for reverse travel. By operating to the “D” position, all forward gear stages “1st” to “6th” are operated. The automatic shift mode (D range) is established in which the vehicle travels forward while automatically switching. Further, when operated to the “R” position, the reverse gear stage “R” is established and the reverse travel is enabled. In addition to the automatic transmission mode, it is also possible to select a manual transmission mode in which other drive ranges such as the 4 range and the 3 range in which the automatic transmission range is limited can be specified. It is also possible to select the automatic transmission mode or the like by using a push button switch or the like instead of the shift lever 72.

On the other hand, from the electronic control unit 90, an engine output control command signal S _E for controlling the output of the engine 30, for example, a signal for driving a throttle actuator for controlling the opening / closing of the electronic throttle valve according to the accelerator operation amount Acc, An injection signal for controlling the amount of fuel injected from the fuel injection device, an ignition timing signal for controlling the ignition timing of the engine 30 by the ignition device, and the like are output. Further, a shift control command signal S _P for shift control of the automatic transmission 10, for example, linear solenoid valves SLC 1, SLC 2, SLB 1, SLB 2, SLB 3 in the hydraulic control device 100 for switching the gear stage of the automatic transmission 10 is set. Control signals are output.

  Specifically, the shift control will be described. For example, in the automatic shift mode, the electronic control unit 90 stores the relationship (map, shift diagram) stored in advance using the vehicle speed V and the accelerator operation amount Acc as parameters as shown in FIG. ) Based on the actual vehicle speed V and the accelerator operation amount Acc, it is functionally provided with a shift control means for executing the shift control according to the determination. At this time, the electronic control unit 90 engages and / or engages the hydraulic friction engagement device involved in the shift of the automatic transmission 10 so that the target gear stage is established according to the engagement operation table shown in FIG. Alternatively, a release command (shift output, hydraulic command), that is, the linear solenoid valves SLC1, SLC2, SLB1, SLB2, and SLB3 in the hydraulic control device 100 are respectively excited or de-energized to the hydraulic actuator of the hydraulic friction engagement device. A command to control the pressure of the supplied hydraulic pressure is output to the hydraulic control device 100.

  The electronic control unit 90 also functions the lockup clutch engagement / release control means 150, the lost drive countermeasure means 152, and the fail determination means 154 shown in FIG. 5 in relation to the operation of the torque converter 32 and the lockup clutch 28. In preparation. The lock-up clutch engagement / release control means 150 controls engagement / release of the lock-up clutch 28 according to, for example, the switching map shown in FIG. 6, and the hydraulic control device 100 controls engagement / release of the lock-up clutch 28. 7, a lockup relay valve 102 whose operation state is switched by a solenoid valve SL, a lockup control valve 104 whose operation state is controlled by a linear solenoid valve SLU, and the like are provided. In FIG. 7, the lockup relay valve 102 and the lockup control valve 104 are pumped up from an oil pan 112 through a strainer 114 by an oil pump 110 that is mechanically driven by the engine 30, and a line oil pressure control circuit 116. Thus, the hydraulic oil adjusted to the second line hydraulic pressure PL2 is supplied through the line oil passage 118, respectively. The line hydraulic control circuit 116 includes a linear solenoid valve SLT, a primary regulator valve, and the like. When the linear solenoid valve SLT is controlled by the electronic control unit 90, the line hydraulic control circuit 116 corresponds to the accelerator operation amount Acc and the like. The second line oil pressure PL2 is adjusted.

  The torque converter 32 includes an engagement side oil chamber 120 and a release side oil chamber 122 on both sides of the lockup clutch 28, and the hydraulic pressure Pon in the engagement side oil chamber 120 and the oil pressure in the release side oil chamber 122. The lockup clutch 28 is engaged with a predetermined engagement torque by a differential pressure ΔP (= Pon−Poff) with respect to Poff. A first oil passage 130 and a third oil passage 134 are connected to the engagement side oil chamber 120, while a second oil passage 132 is connected to the release side oil chamber 122. , 132, 134, the differential pressure ΔP is controlled by the flow of hydraulic oil in and out, and the lockup clutch 28 is engaged (ON) and released (OFF).

  The first oil passage 130, the second oil passage 132, and the third oil passage 134 are all connected to the lockup relay valve 102, and the lockup relay valve 102 is connected to the signal oil pressure from the solenoid valve SL. Thus, an ON side communication state (ON state) indicated by a solid line and an OFF side communication state (OFF state) indicated by a broken line are alternatively switched. When the lock-up relay valve 102 is brought into the ON-side communication state, as shown in FIG. 8, the line oil passage 118 is connected to the first oil passage 130, and the second line oil pressure PL2 is used as the engagement oil pressure. The first oil passage 130 is supplied to the engagement-side oil chamber 120 of the lockup clutch 28, and the second oil passage 132 and the third oil passage 134 are connected to the connection oil passages 136 and 138, respectively. The connection oil passages 136 and 138 are connected to the lockup control valve 104, and are connected to the ON-side communication state (ON state) indicated by the solid line by the signal oil pressure output from the linear solenoid valve SLU. The path 136 is connected to a drain oil path indicated by “EX”, and the working oil is directly recirculated to the oil pan 112, while the connecting oil path 138 is substantially blocked (blocked) to prevent the working oil from flowing out. Further, when the lockup control valve 104 is brought into the OFF side communication state (OFF state) indicated by a broken line by the signal hydraulic pressure output from the linear solenoid valve SLU, the connection oil passage 136 is connected to the line oil passage 118 and is While the two-line hydraulic pressure PL2 is supplied, the connection oil passage 138 is connected to the drain oil passage, and the working oil is returned to the oil pan 112 as it is.

  The hydraulic pressure of the signal hydraulic pressure output from the linear solenoid valve SLU can be continuously changed, and the position of the spool of the lock-up control valve 104 is continuously changed, so that the ON-side communication state and OFF The communication state is continuously changed between the side communication state. That is, the communication state between the connection oil passage 136 and the drain oil passage and the line oil passage 118 is continuously changed, whereby the hydraulic pressure of the connection oil passage 136 and further the hydraulic pressure Poff in the release-side oil chamber 122 are changed. The lockup clutch 28 is continuously adjusted, and in normal control, the lockup clutch 28 is brought into a completely engaged state or a predetermined slip state. The connection oil passage 138 communicated with the third oil passage 134 is opened and closed by the lockup control valve 104 according to the slip state of the lockup clutch 28, and the hydraulic oil in the torque converter 32 is passed through the lockup clutch 28. By draining at a flow rate corresponding to the slip state and introducing new hydraulic oil into the torque converter 32 from the first oil passage 130, temperature rise due to slip is suppressed. When the lock-up control valve 104 is brought into a complete OFF-side communication state, the connection oil passage 136 is connected to the line oil passage 118, and the second line oil pressure PL2 is supplied.

On the other hand, when the lockup relay valve 102 is brought into the OFF side communication state, as shown in FIG. 9, the line oil passage 118 is connected to the second oil passage 132, and the second line oil pressure PL2 is used as the release oil pressure. The oil passage 132 is supplied to the release-side oil chamber 122 of the lockup clutch 28, the first oil passage 130 is connected to the oil cooler 142 via the cooler oil passage 140, and the third oil passage 134 is shut off (closed). Is done. When the lock-up clutch 28 is released, the hydraulic oil in the torque converter 32 is agitated by the relative rotation of the turbine impeller 32t and the pump impeller 32p, and the AT oil temperature T _OIL rises. Is returned to the oil pan 112, the temperature rise of the hydraulic oil is suppressed. The lockup relay valve 102 is switched between the ON-side communication state and the OFF-side communication state by selectively moving the spool to the two positions depending on whether or not a predetermined signal oil pressure is supplied from the solenoid valve SL. . The lockup relay valve 102 corresponds to a first valve, and the lockup control valve 104 corresponds to a second valve. The connection oil passage 136 is a first discharge oil passage, and the cooler oil passage 140 is a second discharge oil passage. When the lock-up relay valve 102 is in the OFF-side communication state, the lock-up clutch 28 is released regardless of whether the lock-up control valve 104 is ON or OFF. In this embodiment, the lock-up control valve 104 is also illustrated in FIG. As shown in FIG.

  Here, in the hydraulic control device 100 for the lockup clutch configured as described above, if the vehicle is stopped in a driving range such as the D range at a low oil temperature such as at the initial start of the engine 30, the low oil temperature Occasionally, the viscosity of the hydraulic oil becomes high and the return to the oil pan 112 becomes slow, so that the oil level (oil level) of the oil pan 112 becomes low, and the hydraulic oil mixed with bubbles due to the suction of air enters the torque converter 32. May be supplied. When the vehicle is stopped, the lock-up clutch 28 is released, and the lock-up relay valve 102 is brought into the OFF-side communication state, whereby air-mixed hydraulic fluid is supplied from the second oil passage 132 into the torque converter 32. The oil is discharged from the first oil passage 130 through the cooler oil passage 140 to the oil cooler 142. However, since the rotation of the turbine impeller 32t is stopped when the vehicle is stopped in the drive range, the bubbles are stopped in the torque converter 32. Easy to accumulate. That is, when rotating, the hydraulic oil is pressed to the outer peripheral side by centrifugal force, whereby bubbles are gathered to the center side, and the hydraulic oil is supplied to the release-side oil chamber 122, whereby the first portion provided on the rotation shaft of the central portion. The hydraulic oil mixed with air bubbles is discharged in the form of being pushed out to the one oil passage 130, but when the rotation is stopped, the air bubbles adhere to the turbine impeller 32t and the like and are easily retained. If a large amount of such bubbles are accumulated in the torque converter 32 due to a long stoppage, the transmission torque of the torque converter 32 cannot be sufficiently obtained due to the presence of the bubbles when the vehicle starts, and the start drive performance is impaired. May cause lost drive.

  As a measure for suppressing such a lost drive, in this embodiment, as shown in the functional block diagram of FIG. 5, a lost drive measure means 152 is provided separately from the lockup clutch engagement / release control means 150. . This lost drive countermeasure means 152 corresponds to an air mixing countermeasure means, and performs signal processing according to the flowchart of FIG.

In step SS1 of FIG. 10, it is determined whether or not the shift lever 72 is in the drive range operated to the “D” position, in other words, whether or not the automatic transmission 10 is in the power transmission state. In step SS5, the lock-up clutch engagement / release control means 150 executes normal engagement / release control, but in the case of the “D” position, step SS2 and subsequent steps are executed. In step SS2, it is determined whether or not the vehicle is in a vehicle stop state where the vehicle speed V is substantially 0. If V≈0, step SS5 is executed. If V≈0, step SS3 is executed. In step SS3, whether or not the AT oil temperature T _OIL that is the temperature of the hydraulic oil is lower than a predetermined value T1, that is, a temperature at which lost drive occurs due to air suction, for example, lower than 0 ° C. If T _OIL <T1, step SS5 is executed. If T _OIL <T1, step SS4 is executed.

  In step SS4, a command for setting the lockup relay valve 102 to the ON side communication state and setting the lockup control valve 104 to the OFF side communication state is output. When the vehicle is stopped, the lockup clutch 28 is released, and the lockup relay valve 102 and the lockup control valve 104 are both in the OFF-side communication state. Therefore, the lockup control valve 104 is substantially connected to the OFF-side communication. A command to switch the lock-up lever valve 102 from the OFF-side communication state to the ON-side communication state is output while the state is maintained. This switching command is for switching between excitation and non-excitation of the solenoid valve SL. As a result, the hydraulic control circuit 100 changes from the state shown in FIG. 9 to the state shown in FIG. 11, the first oil passage 130 is connected to the line oil passage 118, and the second line oil pressure PL2 is applied to the engagement side oil chamber 120. While being supplied, the second oil passage 132 is connected to the line oil passage 118 via the connection oil passage 136 and the lockup control valve 104, and the second line oil pressure PL is supplied to the release-side oil chamber 122. That is, even when the lockup relay valve 102 is switched to the ON-side communication state, the oil pressure in the two oil chambers 120 and 122 is substantially the same, and the lockup clutch 28 is maintained in the released state. By applying the second line hydraulic pressure PL2 to 120, 122, the flow of the hydraulic oil is hindered, and it is suppressed that the hydraulic oil mixed in the air is supplied into the torque converter 32 and the lost drive is generated when the vehicle starts. Driving performance when the vehicle starts at low oil temperature is improved. The hydraulic oil flows out from the third oil passage 134 through the connection oil passage 138, but the flow cross-sectional area of the third oil passage 134 is relatively small, and the viscosity of the hydraulic oil is high at low oil temperature, so the pipeline Since the resistance is large, the flow rate is very small, and compared with the case where the hydraulic oil flows out from the first oil passage 130 as shown in FIG. The lost drive is suppressed.

  By the way, when the lock-up lever valve 102 is switched from the OFF-side communication state to the ON-side communication state when the vehicle is stopped by the lost drive countermeasure unit 152 as described above, the lock-up control valve 104 fails in the electric system, that is, the linear solenoid valve. When the SLU is disconnected or short-circuited, or is fixed to the ON-side communication state by a valve stick of the valve itself, the hydraulic control device 100 is in the state shown in FIG. 12, and the lock-up clutch 28 is engaged and the engine 30 stops rotating. Even when the lock-up control valve 104 is in an intermediate state between the ON-side communication state and the OFF-side communication state and the lock-up clutch 28 is slip-engaged with a predetermined engagement torque, depending on the engagement torque, the engine 30 Is stopped. When the engine 30 is stopped in this manner, the vehicle cannot be started substantially.

For this reason, in this embodiment, as shown in FIG. 5, a fail determination means 154 is provided functionally, and the lock-up control valve 104 is turned ON (ON-side communication state to intermediate) prior to the implementation of the lost drive countermeasure. The spool is fixed in the state). The fail determination means 154 performs signal processing according to the flowchart of FIG. 13. In step S1, whether or not the operation position of the shift lever 72 is the “P” position or the “N” position, that is, the automatic transmission 30 transmits power. It is determined whether or not it is in a shut-off state for shutting off, and if “P” or “N”, step S2 is executed. In step S2, as in step SS3, it is determined whether or not the AT oil temperature T _OIL that is the oil temperature of the hydraulic oil is lower than the predetermined value T1, that is, whether or not the execution condition of the lost drive countermeasure unit 152 is satisfied. If T _OIL <T1, step S3 is executed.

In step S3, the engine speed N _E or not greater than the predetermined value N1 in comparison with the turbine speed N _T, ie, the input side rotation speed of the torque converter 32 increases the viscosity of the hydraulic oil (engine rotational speed N _E ) And the output side rotational speed (turbine rotational speed N _T ), it is determined whether or not ΔN> N1. Step S4 and subsequent steps are executed. Generally, when such a low oil temperature suction of air is a problem, in the rotational resistance of the automatic transmission 10 due to agitation resistance such as high viscosity of the hydraulic oil, turbine rotational speed N _T is compared to the engine rotational speed N _E Therefore, the predetermined value N1 is smaller than the differential rotation (100 to 200 rpm) and is less than the differential rotation (for example, about 25 rpm) at about 80 ° C. where there is no fear of air suction. Is set to a large value, for example, about 50 rpm. As a result, only when there is a possibility of lost drive, step S4 and subsequent steps are executed reliably, and the determination of ON failure of the lockup control valve 104 is performed. In addition to this, it is also possible to add a condition that the vehicle is stopped at a vehicle speed V≈0, that it is before the first start after the engine is started, or the like as a condition for executing step S4 and subsequent steps.

In step S4, a command for switching the lockup relay valve 102 from the OFF-side communication state to the ON-side communication state is output. This switching command is for switching between excitation and non-excitation of the solenoid valve SL. Subsequently, step S5 is executed, and after a predetermined time has elapsed since the command for switching the lockup relay valve 102 to the ON-side communication state is output, the differential rotation ΔN (= N _E −N _T ) It is determined whether or not the value is smaller than the predetermined value N1. The predetermined time is longer than the delay time until the lockup clutch 28 changes to the engaged state and the turbine rotational speed _NT changes when the lockup control valve 104 is in the ON failure state. A time of about 2 to 2 seconds is set.

  If the determination in step S5 is YES (affirmative), that is, if ΔN <N1, it can be estimated that the lockup clutch 28 is in an engaged state, so that the lockup control valve 104 fails in step S6. In step S7, the lost drive countermeasure unit 152 prohibits the implementation of the lost drive countermeasure. Further, this fail information is also supplied to the lockup clutch engagement / release control means 150 to restrict the implementation of slip engagement control and the like controlled using the lockup control valve 104. If necessary, it is stored in a diagnosis or the like, or a failure display is displayed on an instrument panel or the like. On the other hand, if the determination in step S5 is NO (negative), that is, if ΔN ≧ N1, it is assumed that the lockup control valve 104 is operating normally, and the lost drive countermeasure means 152 performs the lost drive in step S8. Allow implementation of measures. Thereafter, in step S9, the lockup relay valve 102 is returned to the OFF-side communication state, and a series of signal processing ends.

The time chart of FIG. 14 shows the case where the lockup control valve 104 is in the ON failure state. At time t1, the determination in step S3 is YES, step S4 is executed, and the lockup relay valve 102 is in the OFF side communication state. Is a time when a command for switching to the ON-side communication state is output. In this example, when the lockup relay valve 102 is in the OFF side communication state (before time t1), the differential rotation ΔN (= N _E −N _T ) was about 200 rpm, whereas the ON side communication state. By switching to, the lockup clutch 28 is engaged due to the ON failure of the lockup control valve 104, and the differential rotation ΔN≈0 is achieved in less than 1 second.

Thus, in the vehicle lockup clutch control device of the present embodiment, by outputting a command to set the lockup control valve 104 to the OFF side communication state and the lockup relay valve 102 to the ON side communication state, Based on the differential rotation ΔN (= N _E −N _T ) between the input side rotational speed and the output side rotational speed of the torque converter 32, it is estimated that ΔN <N1, that is, the lock-up clutch 28 is engaged. In the case of failure, a failure determination is made to the effect that the lockup control valve 104 is in an ON failure state.

Here, for performing failure determination based on the rotational difference ΔN between the engine speed N _E and the turbine rotational speed N _T, the change in the engine rotational speed N _E is the input side rotation speed of the torque converter 32 is not necessarily required In addition, in this embodiment, when “P” or “N” is selected and the automatic transmission 10 is in the shut-off state, the fail determination is performed. Therefore, even if the lockup clutch 28 is engaged during the failure. The fail determination can be appropriately performed without causing the engine 30 to stop rotating.

  Further, in this embodiment, the automatic transmission 10 is disposed between the torque converter 32 and the drive wheel 40, and the fail determination unit 154 sets the automatic transmission 10 to a cutoff state such as neutral. Even if the lockup clutch 28 is engaged and the lockup clutch 28 is engaged at the time of the failure determination, the lockup control valve 104 is turned on without causing the engine 30 to stop rotating. A failure can be determined appropriately. In addition, when “P” or “N” is selected by the shift lever 72, that is, when the automatic transmission 10 is in the shut-off state by the driver's intention, the vehicle is started in order to execute the fail determination. Therefore, it is necessary to move the shift lever 72 to “D” or the like, and there is almost no possibility that the response performance at the time of start is impaired by the execution of the fail determination.

Further, in this embodiment, it is determined in step S2 whether or not the AT oil temperature T _OIL is equal to or lower than a predetermined value T1, and if T _OIL <T1, a fail determination is performed, and the lost drive is performed in steps S7 and S8 according to the determination result. In order to determine whether or not the control by the countermeasure unit 152 is to be performed, until the AT oil temperature T _OIL is relatively high and there is no risk of the hydraulic oil mixed in, and until the control by the lost drive countermeasure unit 152 is not performed. Useless signal processing for fail determination is avoided.

  Further, in this embodiment, when the automatic transmission 10 is stopped in the driving range such as the D range, the lockup relay valve 102 is set to the ON side communication state while the lockup control valve 104 is set to the OFF side communication state. Switching, the second line hydraulic pressure PL2 is supplied to both the engagement side oil chamber 120 and the release side oil chamber 122 so as to inhibit the flow of the hydraulic oil, and the hydraulic oil mixed flows into the torque converter 32. In the case where the lost drive countermeasure means 152 that suppresses this is provided, the hydraulic oil mixed in the air flows into the torque converter 32, and a large amount of bubbles are accumulated when the vehicle is stopped for a long time. The transmission torque of the converter 32 cannot be obtained sufficiently, and the occurrence of lost drive, in which the start drive performance is impaired, is suppressed. In this case, when the lock-up control valve 104 is in an ON-fail state, the hydraulic oil in the release side oil chamber 122 moves from the second oil path 132 to the lock-up relay valve 102, the connection oil path 136, and the lock-up control valve 104. In this embodiment, it is determined whether or not the lock-up control valve 104 is in an ON-fail state, and the lock-up clutch 28 is engaged and the engine 30 stops rotating. Since the execution of control by the lost drive countermeasure means 152 is prohibited at the time of failure, it is avoided that the engine 30 stops rotating due to the execution of the control by the lost drive countermeasure means 152 due to the ON failure of the lockup control valve 104. Is done.

  Next, another embodiment of the present invention will be described. In the following embodiments, parts that are substantially the same as those in the above embodiments are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIGS. 15A and 15B are diagrams showing two examples in a case where a failure determination is made by outputting a command to set one of the lockup relay valve 102 and the lockup control valve 104 to the ON side communication state and the other to the OFF side communication state. Thus, the upper determination method in which the lockup relay valve 102 is in the ON-side communication state and the lockup control valve 104 is in the OFF-side communication state corresponds to the above embodiment. The lower determination method is a case in which a failure determination is made by outputting a command to set the lockup relay valve 102 to the OFF side communication state and the lockup control valve 104 to the ON side communication state. If it is normal, the hydraulic control device 100 is supplied with the second line hydraulic pressure PL2 from the second oil passage 132 to the release side oil chamber 122 as shown in FIG. Is discharged from the first oil passage 130 through the cooler oil passage 140, so that the lockup clutch 28 is released.

  On the other hand, when the lockup relay valve 102 is in the ON failure state, the hydraulic control device 100 sets both the lockup relay valve 102 and the lockup control valve 104 to the ON side communication state as shown in FIG. 8 and the lock-up clutch 28 is engaged. Therefore, for example, by performing signal processing according to the flowchart shown in FIG. 18, it is possible to determine whether or not the lock-up relay valve 102 has failed.

In Steps Q1 to Q3 in FIG. 18, the same processing as Steps S1 to S3 in FIG. 13 is performed, and when both are YES, that is, “P” or “N” is selected and the automatic transmission 10 is cut off. In addition, when the AT oil temperature T _OIL is a low oil temperature equal to or lower than the predetermined value T1, the differential rotation ΔN (= N _E −N _T ) is larger than the predetermined value N1, and the vehicle is stopped immediately after the engine is started. Step Q4 and subsequent steps are executed. Note that the ON failure of the lockup relay valve 102 is not related to whether or not the control by the lost drive countermeasure means 152 is executed, and therefore, the predetermined value T1 regarding the AT oil temperature T _OIL should be set regardless of the intake of air. This step Q2 may be omitted.

In step Q4, a command for switching the lockup control valve 104 from the OFF-side communication state to the ON-side communication state is output. This switching command is for switching between excitation and non-excitation of the linear solenoid valve SLU. When switching to the ON-side communication state by excitation, the lock-up control valve 104 can be completely set to the ON-side communication state. Outputs current (maximum value, etc.). Subsequently, Step Q5 is executed, and it is determined whether or not the differential rotation ΔN (= N _E −N _T ) has become smaller than the predetermined value N1 after a predetermined time has passed, as in Step S5, and ΔN <N1 In this case, in step Q6, a fail determination is made to indicate that the lockup relay valve 102 has been turned on, and the fail information is supplied to the lockup clutch engagement release control means 150 and the like. In step Q7, the lock-up control valve 104 is returned to the OFF-side communication state, and a series of signal processing ends.

In any of the above-described embodiments, the fail determination is executed when “P” or “N” is selected by the shift lever 72. However, as shown in FIG. Fail determination can also be executed when is in a power transmission state. FIG. 19 is for determining ON failure of the lockup control valve 104 as in FIG. 13. In step R1, it is determined whether or not the shift lever 72 is operated to the “D” position, in other words, automatic shifting. It is determined whether or not the machine 10 is in a power transmission state, and if it is in the “D” position, step R2 is executed. In Step R2, it is determined whether or not the vehicle is stopped when the vehicle speed V is substantially 0. If V≈0, Step R3 is executed. In step R3, whether or not the AT oil temperature T _OIL that is the temperature of the hydraulic oil is lower than a predetermined value T1, that is, a temperature at which lost drive occurs due to air suction, for example, lower than 0 ° C. Whether or not T _OIL <T1, step R4 is executed.

  In step R4, the clutch C1, which is the input clutch of the automatic transmission 10, is released (OFF). As a result, power transmission between the torque converter 32 and the drive wheels 40 is interrupted, and the engine 30 is prevented from stopping when the lockup control valve 104 is turned ON. In the following steps R5 to R10, the same processing as that in steps S4 to S9 in FIG. 13 is executed. In step R7, a failure determination is made that the lockup control valve 104 is in the ON failure state, and in step R8, the lost operation is performed. While execution of control by the drive countermeasure means 152 is prohibited, execution of control by the lost drive countermeasure means 152 is permitted in step R9. In step R10, the lockup relay valve 102 is released (OFF) and the clutch C1 is engaged.

  In the embodiment of FIG. 19 as well, the lockup clutch 28 is engaged by the ON failure of the lockup control valve 104 in order to perform the fail determination in a state where the clutch C1 is released and the power transmission of the automatic transmission 10 is cut off. However, the same effect as in the above-described embodiment can be obtained, for example, fail determination can be appropriately performed without causing the engine 30 to stop rotating.

  As mentioned above, although the Example of this invention was described in detail based on drawing, this is an embodiment to the last, and this invention is implemented in the aspect which added various change and improvement based on the knowledge of those skilled in the art. Can do.

1 is a skeleton diagram illustrating a schematic configuration of a vehicle drive device to which the present invention is preferably applied. 2 is a chart for explaining an operating state of a friction engagement device when a plurality of gear stages of the automatic transmission of FIG. 1 are established. It is a block diagram explaining the principal part of the electrical control system provided in the vehicle in order to control the automatic transmission etc. of FIG. It is a figure which shows an example of the shift map used by the shift control of the automatic transmission performed by the electronic controller of FIG. It is a block diagram explaining the function with which the electronic controller of FIG. 3 is provided regarding control of a lockup clutch. It is a figure explaining an example of the switching map used for engagement of a lockup clutch performed by the lockup clutch engagement release control means of FIG. 5, and release control. It is a circuit diagram explaining the principal part structure with which the hydraulic control apparatus is provided regarding engagement and release control of a lockup clutch. FIG. 8 is a diagram showing a circuit configuration when the lockup relay valve is in an ON-side communication state in the hydraulic control device of FIG. 7. FIG. 8 is a diagram showing a circuit configuration when both the lockup relay valve and the lockup control valve are in the OFF-side communication state in the hydraulic control device of FIG. 7. 6 is a flowchart for specifically explaining the processing contents of the lost drive countermeasure means of FIG. 5. FIG. 11 is a circuit diagram showing a state in which a lost drive countermeasure is executed according to the flowchart of FIG. 10 and the lockup relay valve is switched to the ON-side communication state. In FIG. 11, it is a figure which shows the circuit structure in case the lockup control valve is failing ON. 6 is a flowchart for specifically explaining the processing contents of the fail determination means of FIG. 5. When the lockup control valve is in the ON failure state, a command for the rollup relay valve when signal processing is performed according to the flowchart of FIG. 13, and a time chart showing temporal changes in the engine speed and the turbine speed It is an example. It is a figure explaining two types of modes which can perform a fail determination by making one side of a lockup relay valve and a lockup control valve into an ON side communication state, and making the other into an OFF side communication state. It is a figure which shows the circuit structure of the hydraulic-control apparatus when a lockup relay valve is made into an OFF side communication state, and a lockup control valve is made into an OFF side communication state in order to determine ON failure of a lockup relay valve. In FIG. 16, it is a figure which shows a circuit structure in case the lockup relay valve is failing on. FIG. 6 is a flowchart for specifically explaining signal processing when the lockup control valve is switched to an ON-side communication state when the lockup clutch is released and an ON failure of the lockup relay valve is determined. It is a figure explaining further another Example of this invention, and is a flowchart explaining the signal processing at the time of determining ON failure of a lockup control valve, when a shift lever is operated to "D" position. is there.

Explanation of symbols

10: Automatic transmission (intermittent mechanism) 28: Lock-up clutch 30: Engine (drive power source) 32: Torque converter (fluid power transmission device) 40: Drive wheel 90: Electronic control device 102: Lock-up relay valve 104: Lock-up control valve (second valve) 118: Line oil passage 120: Engagement side oil chamber 122: Release side oil chamber 136: Connection oil passage (first discharge oil passage) 140: Cooler oil passage (Second discharge oil passage) 152: Lost drive countermeasure means (air mixing countermeasure means) 154: Fail determination means N _E : Engine rotation speed (input side rotation speed) N _T : Turbine rotation speed (output side rotation speed) ΔN : Differential rotation T _OIL : AT oil temperature (hydraulic oil temperature)

Claims (4)

It is provided in a fluid power transmission device to which power is transmitted from a driving force source, and is engaged based on a differential pressure between the hydraulic pressure in the engagement side oil chamber and the hydraulic pressure in the release side oil chamber. A lock-up clutch that directly connects the input side and output side of the transmission device;
An ON state in which hydraulic oil is supplied to the engagement side oil chamber and the release side oil chamber is connected to the first discharge oil passage, and hydraulic oil is supplied to the release side oil chamber and the engagement side oil chamber A first valve that is switched to an OFF state that connects to the second discharge oil passage;
A second valve that is switched between an ON state for discharging the hydraulic oil in the first discharge oil passage and an OFF state for supplying the hydraulic oil to the first discharge oil passage;
The lock-up clutch is engaged when both the first valve and the second valve are turned on, and the lock-up clutch is released when the first valve is turned off. In a control device for a lockup clutch for a vehicle,
A command to turn on one of the first valve and the second valve and turn off the other is output, and a change in the output side rotational speed of the fluid power transmission device or the output side rotational speed A control device for a lockup clutch for a vehicle, comprising: a fail determination unit that performs a failure determination of the first valve or the second valve based on a differential rotation with an input side rotational speed. Between the fluid power transmission device and the drive wheel, an intermittent mechanism capable of switching between a power transmission state and a cutoff state is provided,
The control apparatus for a vehicle lock-up clutch according to claim 1, wherein the fail determination unit performs the fail determination when the interrupting mechanism is in a shut-off state. The control device for a lockup clutch for a vehicle according to claim 1 or 2, wherein the fail determination means performs the fail determination when an oil temperature of the hydraulic oil is equal to or lower than a predetermined value. A command to turn on the first valve and turn off the second valve when the vehicle is stopped is output so that hydraulic oil is supplied to both the engagement side oil chamber and the release side oil chamber. While having air mixing countermeasures that hinder the flow of hydraulic oil,
The fail judging means outputs a command to turn on the first valve and turn off the second valve, change the output side rotational speed of the fluid power transmission device, or input the output side rotational speed When it is estimated that the lockup clutch is in an engaged state based on a differential rotation with respect to the side rotational speed, it is determined that the second valve is in an on-fail state,
The vehicle lockup clutch according to any one of claims 1 to 3, wherein it is determined whether or not to perform control by the air mixing countermeasure means based on a determination result of the fail determination means. Control device.

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