JP5811001B2 - Vehicle equipped with torque converter - Google Patents

Description

  The present invention relates to control of a vehicle equipped with a torque converter with a lockup clutch.

  A vehicle in which an engine and an automatic transmission are connected via a torque converter having a lock-up clutch is often used. Such a vehicle torque converter includes a pump impeller coupled to an engine output shaft (crankshaft), a turbine runner coupled to an input shaft of an automatic transmission, and a stator. In this type of fluid transmission device, the pump impeller rotates and the turbine runner is rotationally driven by the hydraulic oil discharged from the pump impeller to transmit the output torque of the engine to the input shaft of the automatic transmission.

  The lock-up clutch directly connects the input side (pump side) and the output side (turbine side) of the torque converter by engaging, but the lock-up clutch is intermediate between the engaged state and the released state. There has also been proposed a structure capable of making the input side (pump side) and the output side (turbine side) slip in a half-engaged state.

  In a vehicle equipped with such a torque converter, for example, when traveling in a lockup-off state with a high-speed gear when traveling uphill, the temperature of the hydraulic oil rises due to the loss of the torque converter, In some cases, the hydraulic oil deteriorates and the performance of the hydraulic control system decreases. For this reason, when the temperature of the hydraulic fluid of a torque converter becomes high temperature, the method which suppresses heat_generation | fever of a torque converter by making a lockup clutch into an engagement state is proposed (for example, refer patent document 1).

  In a torque converter with a lock-up clutch capable of slip control, a lock-up switching valve that switches engagement and disengagement of the lock-up clutch, and a lock-up that controls the hydraulic pressure of hydraulic oil supplied to the torque converter through the lock-up switching valve. Many have a control valve (see, for example, Patent Document 2). In this configuration, the oil pressure in both the engagement-side pressure chamber and the release-side pressure chamber of the torque converter is adjusted by a single lock-up control valve, so that the lock-up clutch is engaged and released by the lock-up switching valve. In order to reduce shock due to sudden engagement during lockup, it is necessary to operate the lockup switch valve after reducing the pressure of the hydraulic oil supplied from the lockup control valve once. . For this reason, a delay may occur in the lock-up operation.

Japanese Patent Laid-Open No. 4-151069 JP 2010-127380 A

  By the way, in recent years, a flex start that starts the vehicle while suppressing the slip rotation of the torque converter by causing the lock-up clutch to be in a slip state and generating an engagement force in the lock-up clutch has been frequently used. Since this flex start can improve fuel efficiency, it is preferable to perform the flex start as much as possible when starting the vehicle.

  However, it is necessary to set the lock-up clutch to the slip state at the time of flex start. In this state, the flow rate of the working oil flowing through the torque converter is reduced, and the cooling of the working oil is limited. For this reason, when the temperature of the hydraulic fluid of the torque converter has become high due to the traveling state immediately before the start of the vehicle, priority is given to cooling of the hydraulic fluid of the torque converter, and the lock-up clutch is released and the vehicle is It is necessary to start.

  On the other hand, for example, the torque converter is brought into the lock-up released state during the stop state immediately before the vehicle starts, the hydraulic oil flow rate is increased to lower the hydraulic oil temperature, and the torque converter is then slipped. As a method, a flex start method can be considered. However, in the case of a configuration in which the hydraulic pressures of both the engagement side pressure chamber and the release side pressure chamber of the torque converter are adjusted by one lockup control valve as described in Patent Document 2, the lockup operation is performed. Due to the delay, when the vehicle starts, it may not be possible to smoothly transition to the flex start and the flex start may not be performed.

  In addition, when the temperature of the hydraulic fluid of the torque converter before the start of the vehicle is low, there is a case where it is not necessary to cool the hydraulic fluid by increasing the flow rate of the hydraulic fluid of the torque converter in the stop state before the vehicle starts. is there.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to improve the fuel consumption by enabling frequent use of a flex start in a vehicle equipped with a torque converter with a lock-up clutch.

The torque converter-equipped vehicle of the present invention includes a torque converter including a lock-up clutch that engages and releases according to the hydraulic pressure of the engagement side oil chamber and the hydraulic pressure of the release side oil chamber, and the operation supplied to each of the oil chambers. A torque converter-equipped vehicle including a common hydraulic control valve that adjusts the oil pressure of the oil and a control unit that controls the operation of the hydraulic control valve, wherein the control unit has a first oil temperature of the hydraulic oil. When the vehicle is stopped, the hydraulic pressure control valve holds the hydraulic pressure of the hydraulic oil at a second hydraulic pressure lower than the first hydraulic pressure for cooling the hydraulic oil when the vehicle is stopped. a first vehicle onset Susumute stage performing flex start, wherein when the working oil temperature is equal to or larger than the first threshold value, when the vehicle is stopped, the hydraulic oil pressure of the hydraulic fluid by the hydraulic control valve Maintained at the first hydraulic pressure for cooling. And, possess a second vehicle starting means suppressing flex start to when the vehicle starts, the first vehicle starting means, at the start of the vehicle, when the accelerator opening is equal to or more than the third threshold value The hydraulic pressure of the hydraulic oil is held at the second hydraulic pressure by the hydraulic pressure control valve for a predetermined time, and the hydraulic pressure of the hydraulic oil is increased by the hydraulic pressure control valve after the predetermined time has elapsed. It is characterized by raising from .

  In the torque converter-equipped vehicle of the present invention, when the oil temperature of the hydraulic oil is equal to or higher than the first threshold when the vehicle is stopped, and the oil temperature of the hydraulic oil is lowered below the first threshold while the vehicle is stopped It is also preferable that the hydraulic pressure of the hydraulic oil is reduced to the second hydraulic pressure by the hydraulic pressure control valve.

In the torque converter equipped vehicle of the present invention, includes a passage switching valve for switching the flow of hydraulic fluid to the previous SL respective oil chambers, said first vehicle starting means may further control the operation of the flow path switching valve, When the accelerator opening is equal to or greater than a third threshold when the vehicle starts, the flow path switching valve is switched so that the hydraulic oil flows to the engagement side oil chamber, and at least the hydraulic control valve It is also preferable to increase or decrease the oil pressure in the release- side oil chamber so that the lock-up clutch is in a slip state.

  In the vehicle equipped with the torque converter according to the present invention, the second vehicle starter may cause the hydraulic fluid to flow through the flow path switching valve when the accelerator opening is equal to or greater than a third threshold value when the vehicle starts. It is also preferable that the hydraulic pressure of the hydraulic oil is maintained at the first hydraulic pressure by switching to flow to the release side oil chamber.

In the vehicle equipped with the torque converter according to the present invention, when the accelerator opening is equal to or greater than a third threshold value at the time of starting the vehicle, the control unit causes the hydraulic oil to flow to the engagement side oil chamber by the flow path switching valve. It is also preferable that at least the hydraulic pressure in the release side oil chamber is increased or decreased by the hydraulic pressure adjusting valve to bring the lockup clutch into a slip state.

  According to the present invention, in a vehicle equipped with a torque converter with a lock-up clutch, it is possible to make frequent use of flex start and improve fuel efficiency.

1 is a system diagram showing a configuration of a vehicle equipped with a torque converter in an embodiment of the present invention. It is a flowchart which shows operation | movement of the torque converter mounting vehicle in embodiment of this invention. It is explanatory drawing which shows the flow of the hydraulic fluid of the torque converter mounting vehicle in embodiment of this invention. It is explanatory drawing which shows the flow of the hydraulic fluid of the torque converter mounting vehicle in embodiment of this invention. It is explanatory drawing which shows the flow of the hydraulic fluid of the torque converter mounting vehicle in embodiment of this invention. It is a graph which shows the change of the speed of the torque converter mounting vehicle in embodiment of this invention, oil temperature, an accelerator opening degree, the oil_pressure | hydraulic of a lockup hydraulic pressure control valve exit, and a lockup differential pressure | voltage.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, a vehicle 100 equipped with the torque converter of this embodiment includes a torque converter 10, an oil pump 40 that supplies hydraulic oil to the torque converter 10, and the pressure of the hydraulic oil that is supplied to the torque converter 10. A lock-up hydraulic control valve 20 to be adjusted, a lock-up switching valve 30 for switching a hydraulic oil supply line to the torque converter 10, and a linear solenoid valve 43 for adjusting a control hydraulic pressure P _SLU supplied to the lock-up hydraulic control valve 20 When a solenoid valve 44 for adjusting the control pressure P _SL supplied to the lockup switching valve 30, a regulator 42 for reducing the discharge pressure of the oil pump 40 linear solenoid valve 43, the hydraulic supply pressure P _M of the solenoid valve 44, It has.

  As shown in FIG. 1, the torque converter 10 includes a pump impeller 12 on the input shaft side to which power from the engine is input, a turbine runner 11 on the output shaft side that outputs power to the automatic transmission, a stator 13, The power transmission from the engine to the automatic transmission is performed between the pump impeller 12 and the turbine runner 11 via the hydraulic oil.

The torque converter 10 is provided with a lockup clutch 14 that directly connects the input side and the output side of the torque converter 10. As shown in FIG. 1, the lock-up clutch 14 includes an engagement side oil chamber 15 and a release side oil chamber 16 in which hydraulic pressure is adjusted by taking hydraulic oil into and out of the engagement side port 17 and the release side port 18. Differential pressure (lockup differential pressure) ΔP between the oil pressure in the engagement side oil chamber 15 and the oil pressure in the release side oil chamber 16 (ΔP = hydraulic pressure P _ON in the engagement side oil chamber 15 −release side oil chamber) 16 is a hydraulic friction clutch that is frictionally engaged with the front cover 19 by the hydraulic pressure P _OFF ). The lockup clutch 14 is engaged by controlling the lockup differential pressure ΔP to be positive, and is released when the lockup differential pressure ΔP is controlled to be negative. Further, by adjusting the lockup differential pressure ΔP, it is possible to achieve a half-engagement in the slip state.

When the lockup clutch 14 is completely engaged, the pump impeller 12 and the turbine runner 11 rotate together. Further, by engaging the lockup clutch 14 in a predetermined slip state (half-engaged state), the turbine runner 11 rotates following the pump impeller 12 with a predetermined slip amount during driving. On the other hand, by setting the lockup differential pressure ΔP to be negative (hydraulic pressure P _OFF in the disengagement side oil chamber 16> hydraulic pressure P _ON in the engagement side oil chamber 15), the lockup clutch 14 is disengaged and the pump impeller 12 Power is transmitted from the engine to the automatic transmission via the hydraulic oil with the turbine runner 11.

Lockup switching valve 30, the engagement of the lock-up clutch 14 in accordance with the control oil pressure P _SL from the solenoid valve 44 (lockup ON), a valve for switching the release (lockup OFF), disposed within The spool valve element is moved in the axial direction to switch the connection flow path. In FIG. 1, the lock-up switching valve 30 is not an actual internal structure but a schematic diagram for explaining its function.

As shown in FIG. 1, the lockup switching valve 30 is engaged with an input port 32 a to which hydraulic oil of hydraulic pressure Pb supplied from the lockup hydraulic pressure adjustment valve 20 is input and an engagement side oil chamber 15. A side oil chamber communication port 35a, an engagement side discharge port 37a for discharging the working oil in the engagement side oil chamber 15, a release side oil chamber communication port 36a communicating with the release side oil chamber 16, and a release side oil chamber A release side discharge port 38 a for discharging 16 hydraulic oil and a control pressure input port 31 a to which the control hydraulic pressure P _SLU is input from the linear solenoid valve 43 are provided. Inside the lockup switching valve 30, a first switching mechanism 32 that switches between fluid communication between the input port 32a and the engagement-side internal flow path 32b and fluid communication between the input port 32a and the release-side internal flow path 32c; A second switching mechanism 33 that switches between fluid communication between the engagement side oil chamber communication port 35a and the engagement side internal flow path 32b and fluid communication between the engagement side oil chamber communication port 35a and the engagement side discharge port 37a; A third switching mechanism 34 that switches between fluid communication between the release side oil chamber communication port 36a and the release side internal flow path 32c and fluid communication between the release side oil chamber communication port 36a and the release side discharge port 38a. ing. Each switching mechanism 32, 33, 34 is connected to a common internal link 39. The internal link 39 moves in the axial direction by the pressure of the control hydraulic chamber 31 to which the control pressure input port 31a is connected, and operates each switching mechanism 32, 33, 34 to switch each flow path. Further, the engagement side oil chamber communication port 35 a is connected to the engagement side port 17 of the torque converter 10 by the engagement side oil chamber communication pipe 35, and the release side oil chamber communication port 36 a is released by the release side oil chamber communication pipe 36. It is connected to the side port 18. Further, the engagement side discharge port 37 a is connected to the engagement side discharge pipe 37, and the release side discharge port 38 a is connected to the first communication port 26 a of the lockup hydraulic pressure control valve 20 by the communication pipe 38.

When the lockup clutch 14 is engaged (lockup ON), the lockup hydraulic pressure adjusting valve 20 moves the internal spool valve element in the axial direction according to the control hydraulic pressure P _SLU from the linear solenoid valve 43. The hydraulic pressure of the hydraulic oil supplied to the lockup switching valve 30 and the hydraulic pressure of the release side oil chamber 16 are adjusted. In FIG. 1, the lock-up hydraulic control valve 20 is not a real internal structure but a schematic diagram for explaining its function.

As shown in FIG. 1, the lockup hydraulic pressure control valve 20 includes an input port 22a to which hydraulic oil Pb supplied from an oil pump 40 is input, and a hydraulic pressure Pa input to the input port 22a. A first adjustment mechanism 22 that adjusts to the hydraulic pressure Pb supplied to 30; an output port 25a that outputs hydraulic oil adjusted to the hydraulic pressure Pb; and a first communication port that communicates with the release-side discharge port 38a of the lockup switching valve 30. 26a, a discharge port 27a to which the discharge pipe 27 is connected, a second connection port 28a connected by the output port 25a and the second connection pipe 28, and a control pressure to which the control hydraulic pressure P _SLU is input from the linear solenoid valve 43 And an input port 21a. Further, in the lock-up hydraulic pressure control valve 20, in addition to the first adjustment mechanism 22 described above, the degree of communication with the first communication port 26a, the second communication port 28a, and the discharge port 27a is adjusted. Is provided with a second adjusting mechanism 23 for adjusting the hydraulic pressure of the first communication port 26a. Each adjusting mechanism 22, 23 is connected to a common internal link 29. The internal link 29 moves in the axial direction according to the control oil pressure P _SLU of the control oil pressure chamber 21 to which the control pressure input port 21a is connected, and operates the adjusting mechanisms 22 and 23 to adjust the oil pressure.

  The oil pump 40, the linear solenoid valve 43, and the solenoid valve 44 are each connected to the control unit 50, and are configured to operate according to commands from the control unit 50. Further, the output port 25a of the lockup hydraulic control valve 20 and the input port 32a of the lockup switching valve 30 are connected by a communication pipe 25, and the communication pipe 25 is connected to the outlet of the lockup hydraulic control valve 20 or the lockup. A pressure sensor 45 for detecting the hydraulic pressure Pb at the inlet of the switching valve 30 is attached, a temperature sensor 46 for detecting the temperature T of the hydraulic oil is attached to the torque converter 10, and a vehicle speed V is detected for the vehicle 100. A speed sensor 47 and an accelerator opening sensor 48 for detecting the accelerator opening are provided. Each sensor 45, 46, 47, 48 is connected to the control unit 50, and the control unit 50 is configured to acquire the hydraulic pressure Pb, temperature T, vehicle speed V, and accelerator opening S.

The operation of the vehicle 100 described above will be described with reference to FIGS. When the vehicle 100 is traveling at a certain vehicle speed V, the lockup clutch 14 of the torque converter 10 is in an engaged state (lockup ON). When a command for engaging the lockup clutch 14 is output from the control unit 50, the solenoid valve 44 shuts off the control hydraulic pressure _PSL . As a result, the control hydraulic pressure _PSL is not supplied to the control hydraulic pressure chamber 31 of the lock-up switching valve 30, so that the internal link 39 is pressed against the control hydraulic pressure chamber 31 by a spring (not shown), and as shown in FIG. The switching mechanism 32 communicates the input port 32a and the engagement side internal flow path 32b and blocks the release side internal flow path 32c, and the second switching mechanism 33 communicates the engagement side internal flow path 32b and the engagement side oil chamber communication port. 35a is communicated, the engagement side discharge port 37a is shut off, and the release side oil chamber communication port 36a and the release side discharge port 38a are connected by the third switching mechanism 34. Further, the linear solenoid valve 43 shuts off the control hydraulic pressure P _SLU according to a command from the control unit 50 to engage the lockup clutch 14. As a result, the control hydraulic pressure P _SLU is not supplied to the lockup hydraulic control valve 20 and the control hydraulic chamber 21 is not supplied. pressure Pb supplied to the valve 30 is adjusted to the first hydraulic P _1, a first communication port 26a by the second adjustment mechanism is passed through the discharge ports 27a are communicated, the second connection port 28a is shut off. As will be described later, the first hydraulic pressure P ₁ can cool the hydraulic oil by increasing the flow rate of the hydraulic oil that flows when the lockup clutch 14 is released (lockup OFF). Pressure.

As described above, when the lockup switching valve 30 and the lockup hydraulic pressure control valve 20 are operated, the hydraulic oil supplied from the oil pump 40 through the hydraulic oil supply pipe 24 as shown by the thick line in FIG. It is adjusted to the first hydraulic pressure P ₁ by the lockup hydraulic pressure control valve 20 and is input to the lockup switching valve 30 through the connecting pipe 25. The hydraulic oil input to the lockup switching valve 30 passes from the input port 32a through the engagement side internal flow path 32b, through the engagement side oil chamber communication port 35a, through the engagement side oil chamber communication pipe 35, and to the torque converter 10. From the engagement side port 17 to the engagement side oil chamber 15. For this reason, the hydraulic pressure in the engagement side oil chamber 15 is the first hydraulic pressure P ₁ . On the other hand, the hydraulic oil in the release side oil chamber 16 enters the release side oil chamber communication port 36a from the release side port 18 through the release side oil chamber connection pipe 36, and locks from the release side discharge port 38a through the connection pipe 38. It enters the communication port 26a of the up hydraulic pressure control valve 20, and is discharged from the discharge pipe 27 through the discharge port 27a from the communication port 26a. For this reason, the hydraulic pressure in the release-side oil chamber 16 is substantially zero, and the differential pressure (lock-up differential pressure) ΔP (ΔP = engagement side) between the hydraulic pressure in the engagement-side oil chamber 15 and the hydraulic pressure in the release-side oil chamber 16 The hydraulic pressure P _ON in the oil chamber 15 -the hydraulic pressure P _OFF in the release-side oil chamber 16) becomes the first hydraulic pressure P ₁ , and the lockup clutch 14 is pressed against the front cover 19 and frictionally engaged with the front cover 19. It has become.

Control unit 50, as shown in step S101 of FIG. 2, obtains the speed of the vehicle from the speed sensor 47 is compared with a predetermined speed V ₀ as shown in step S102 of FIG. When the vehicle speed is not equal to or lower than the predetermined speed V ₀ (when it exceeds the predetermined speed V ₀ ), the engagement state (lock-up ON) of the lock-up clutch 14 is maintained. However, as shown in FIG. 6C from time zero to time t ₁ , the control unit 50 changes the hydraulic pressure Pb at the outlet of the lockup hydraulic control valve 20 or the inlet of the lockup switching valve 30 as the vehicle speed decreases. lowering towards the lower second hydraulic P ₂ than the first pressure P ₁ from the first hydraulic P _1. The control oil pressure P _LSU output from the linear solenoid valve 43 is gradually increased by a command from the control unit 50, whereby the internal link 29 moves little by little in the direction opposite to the control oil pressure chamber 21. This first adjusting mechanism 22 is operated in response to a command pressure from the control unit 50 by a hydraulic pressure Pb from the first hydraulic pressure P ₁ toward the second hydraulic P ₂ is varied. When the pressure Pb which is input to the lock-up switch valve 30 is reduced to the second pressure P _2, the pressure of the engagement side oil chamber 15 is also reduced to P _2. Since the oil pressure in the release-side oil chamber 16 is substantially zero and does not change, the lockup differential pressure ΔP also changes from the first oil pressure P ₁ to the second oil pressure P ₂ as shown in FIG. 6D from time zero to t _1. descend.

Then, step S102 in FIG. 2, as shown in the solid line a of FIG. 6 (a), when the vehicle speed in time t ₁ is the predetermined speed V ₀ or less, the control unit 50, as shown in step S103 of FIG. 2, locking A command to release the up clutch 14 (lock up OFF) is output. In response to this command, the solenoid valve 44 outputs the control hydraulic pressure _PSL to the lockup switching valve 30. As a result, the hydraulic pressure in the control hydraulic chamber 31 becomes P _SL , the internal link 39 moves in the opposite direction to the control hydraulic chamber 31, and the first, second, and third switching mechanisms 32, 33, and 34 are reversed, as shown in FIG. As shown, the input port 32a and the release side internal flow path 32c are communicated by the first switching mechanism 32 and the engagement side internal flow path 32b is blocked, and the engagement side oil chamber communication port 35a is disconnected by the second switching mechanism 33. The engagement side discharge port 37a is communicated, and the release side oil chamber communication port 36a and the release side internal flow path 32c are communicated by the third switching mechanism 34 and the release side discharge port 38a is blocked. As a result, the hydraulic oil input to the lockup switching valve 30 is supplied to the release-side oil chamber 16, and the hydraulic pressure P _OFF of the release-side oil chamber 16 becomes the second hydraulic pressure P ₂ . oil pressure P _ON in the engagement side oil chamber 15 is discharged from the engaging side exhaust pipe 37 through the engagement-side oil chamber connecting pipe 35 becomes substantially zero. Therefore, as shown at time t ₁ in FIG. 6D, the lockup differential pressure ΔP becomes −P ₂ , and the lockup clutch 14 moves away from the front cover 19. The hydraulic oil discharged from the engagement side discharge pipe 37 is cooled by an oil cooler (not shown) and then supplied to the oil pump 40, and flows into the release side oil chamber 16 from the lockup hydraulic pressure control valve 20 and the lockup switching valve 30. . As described above, when the lockup clutch 14 is released (lockup OFF), the hydraulic oil is released from the release side oil chamber 16 to the engagement side oil chamber 15, the lockup switching valve 30, the engagement side discharge pipe 37, Since the oil cooler, the oil pump 40, the lockup hydraulic pressure control valve 20, the lockup switching valve 30, and the release side oil chamber 16 circulate, the higher the hydraulic oil pressure, the greater the circulating flow rate and the greater the hydraulic oil cooling. If the hydraulic oil pressure is low, the circulating oil flow is small and the cooling of the hydraulic oil is not so great.

After releasing the lock-up clutch 14, the control unit 50 acquires the temperature T of the hydraulic oil of the torque converter 10 by the temperature sensor 46 attached to the torque converter 10 shown in FIG. 1, as shown in step S104 of FIG. and obtains the vehicle speed V by the speed sensor 47, obtains the accelerator opening S by the accelerator opening sensor 48, the first thresholds T _1, respectively, the second threshold value V _1, the third with the threshold S ₁ Comparative . Then, as shown in step S105 of FIG. 2, the hydraulic oil temperature T indicated by the dotted line b in FIG. 6A is less than the first threshold value T ₁ at time t ₂ in FIG. 6A. And the vehicle speed V indicated by the solid line a in FIG. 6A is less than the second threshold value V ₁ , and the accelerator opening S indicated by the solid line e in FIG. 6B is less than the third threshold value S _1. In this case, it is determined that the vehicle 100 is stopped, the temperature of the hydraulic oil of the torque converter 10 is low, and it is not necessary to greatly cool the hydraulic oil during the stop, and as shown in step S106 of FIG. The hydraulic pressure Pb at the outlet of the control valve 20 or the inlet of the lock-up switching valve 30 is held at a _second hydraulic pressure P ₂ lower than the first hydraulic pressure P ₁ for increasing the cooling of the hydraulic oil. Further, as shown by the one-dot chain line c and the two-dot chain line d in FIG. 6A, when the oil temperature T of the hydraulic oil is equal to or higher than the _first threshold T _{1 at} the time t ₂ when the vehicle 100 stops, the operation is performed. It is determined that large cooling of the oil is necessary, and the first hydraulic pressure P _{1 at} which large cooling of the hydraulic oil can be performed is maintained as shown in step S114 of FIG.

When the hydraulic pressure Pb at the outlet of the lockup hydraulic pressure control valve 20 or the inlet of the lockup switching valve 30 is held at the _second hydraulic pressure P2, the control unit 50, as shown in step S107 in FIG. get the accelerator opening S 48, waits until the accelerator opening S becomes the third threshold value S ₁ or more. Then, as shown by the solid line e in FIG. 6B, when the accelerator opening S becomes equal to or greater than the third threshold value S _{1 at} time t ₄ , the lockup clutch 14 is engaged as shown in step S108 in FIG. Outputs a command to turn on (lock-up ON). By this command, the solenoid valve 44 is operated, the supply of the control hydraulic pressure _PSL to the lockup switching valve 30 is stopped, and the first, second, and third switching mechanisms 32, 33, 34 of the lockup switching valve 30 are stopped. Operates to form a flow path through which hydraulic oil flows as shown by the thick line in FIG. Then, the hydraulic pressure P _ON of the engagement side oil chamber 15 becomes the second hydraulic pressure P ₂ , the hydraulic pressure P _OFF of the release side oil chamber 16 becomes substantially zero, and as shown by the solid line j in FIG. the lock-up differential pressure ΔP to t ₄ is the P _2. At this time, the lockup differential pressure ΔP fluctuates from −P ₂ to P _2, but the second hydraulic pressure P ₂ is smaller than the first hydraulic pressure P _1, so the lockup hydraulic pressure small amount of variation of the lock-up differential pressure [Delta] P, occurrence of shock due to sudden engagement of the lockup clutch 14 is suppressed than the case where the hydraulic pressure Pb of the outlet of the regulator valve 20 is held in the first hydraulic pressure P ₁ .

Then, as shown in step S109 in FIG. 2, the control unit 50 adjusts the lockup differential pressure ΔP and engages the lockup clutch in a sliding state to perform a flex start that starts the vehicle 100. In this case, the control unit 50 outputs a command value for the lockup differential pressure ΔP to the linear solenoid valve 43. The linear solenoid valve 43 increases or decreases the control hydraulic pressure P _SLU supplied to the lockup hydraulic pressure control valve 20 according to a command from the control unit 50. As shown in FIG. 5, when the control hydraulic pressure P _SLU is changed, the internal link 29 is activated, the second adjusting mechanism 23 is activated, and the second communication port 28a and the first communication port 26a are communicated to lock up. from the output port 25a of the hydraulic control valve 20 the hydraulic fluid of the second hydraulic P ₂ flows from the second communication port 28a to the first communication port 26a, the hydraulic oil first communication pipe 38, the lockup switching valve 30, the release side By supplying the release side oil chamber 16 from the oil chamber communication pipe 36, the hydraulic pressure P _OFF of the release side oil chamber 16 is increased. Since the engagement side oil chamber 15 is held at the second oil pressure P ₂ as shown by a solid line f in FIG. 6C, when the oil pressure P _OFF of the release side oil chamber 16 is increased, the lockup differential pressure ΔP is Decrease. Conversely, when the lockup differential pressure ΔP is increased, the control oil pressure P _SLU is changed, the second adjusting mechanism 23 is operated, and the flow rate of the hydraulic oil supplied to the release-side oil chamber 16 is reduced. Thus, the pressure in the release side oil chamber 16 is reduced. As indicated by a solid line j from time t ₄ to time t ₅ in FIG. 6D, the control unit 50 adjusts the lock-up differential pressure ΔP in accordance with the start of the vehicle 100, and sets the lock-up clutch 14 to the slip state. Is started (first vehicle starting means).

Then, as shown in step S110 of FIG. 2, the control unit 50 determines that the start of the vehicle 100 by the flex start has ended when a predetermined time has elapsed since the start of the vehicle 100, and step S111 of FIG. As shown at time t ₅ in FIG. 6 (c), the hydraulic pressure Pb at the outlet of the lockup hydraulic pressure control valve 20 is stopped from being held at the second hydraulic pressure P ₂ , and the hydraulic pressure Pb is changed from the second hydraulic pressure P _2. raised, it moves to normal control as shown in step S113 in FIG. 2, raises the pressure Pb of the outlet of the lock-up hydraulic regulating valve 20 from the second hydraulic P ₂ according to the vehicle speed V.

Further, when the control unit 50 holds the hydraulic pressure Pb at the outlet of the lockup hydraulic pressure control valve 20 at the first hydraulic pressure P ₁ in step S114 of FIG. 2, as shown in steps S115 and S116 of FIG. When the vehicle 100 is stopped and the accelerator opening S is not equal to or greater than the third threshold value S ₁ (less than S ₁ ), the hydraulic oil temperature T is acquired and compared with the first threshold value T ₁ . Since the hydraulic pressure Pb at the outlet of the lock-up hydraulic pressure control valve 20 is held at the first hydraulic pressure P ₁ , the flow rate of the hydraulic oil that circulates between the torque converter 10 and the oil cooler is large. As indicated by the alternate long and short dash line c, the oil temperature of the hydraulic oil at the time t ₃ during the stop of the vehicle 100 even when the oil temperature of the hydraulic oil is higher than the first threshold value T _{1 at} the time t ₂ when the vehicle 100 stops. 2 is less than the first threshold value T ₁ , the process proceeds to step S106 in FIG. 2, and the outlet of the lock-up hydraulic pressure control valve 20 at time t ₃ as shown by the one-dot chain line g in FIG. Is reduced to the second hydraulic pressure P ₂ . At this time, the lock-up differential pressure ΔP becomes −P _{2 as} indicated by a one-dot chain line k in FIG. Then, the control unit 50, as explained above, carry out the flex start as the state slip lockup clutch 14 When exceeding accelerator opening S is the threshold value S _1. Again, during the start of the vehicle 100, FIG. 6 as shown in solid line j of the (d), the time t ₄ in the lock-up differential pressure ΔP is pressure P ₂ smaller second than the first pressure P ₁ Therefore, at time t ₃ , the hydraulic pressure Pb at the outlet of the lockup hydraulic pressure control valve 20 is not reduced from the _first hydraulic pressure P ₁ to the second hydraulic pressure P ₂ but is held at the _first hydraulic pressure P _1. When the lockup differential pressure ΔP varies from −P ₁ to P ₁ as in the case where the lockup differential pressure ΔP varies, the amount of fluctuation of the lockup differential pressure ΔP is smaller, and the occurrence of shock due to the sudden engagement of the lockup clutch 14 is suppressed.

As indicated by a two-dot chain line d in FIG. 6A, the control unit 50 determines that the hydraulic oil temperature is higher than the first threshold T _{1 at} the time t ₂ when the vehicle 100 stops and the vehicle 100 is stopped. of the oil temperature of the hydraulic oil to a time t _3, not the first less than the threshold value T _1, exceeds accelerator opening S is the threshold value S ₁ at the threshold value T ₁ or more state oil temperature T is in the first hydraulic oil Then, as indicated by a two-dot chain line h in FIG. 6C, the lockup clutch 14 is released (lockup OFF) while the hydraulic pressure Pb at the outlet of the lockup hydraulic pressure control valve 20 is held at the _first hydraulic pressure P1. The vehicle 100 is started as it is. In this case, the lockup differential pressure ΔP remains held at −P _{1 as} indicated by a two-dot chain line m in FIG.

In this case, as described above, similarly to the control temperature of the hydraulic oil is lower than the first thresholds T ₁ at the time the vehicle 100 is started, the lock-up switch by operating the solenoid valve 44 to the time t ₄ When the valve 30 is switched and the lockup clutch 14 is engaged (lockup ON), the hydraulic pressure P _ON of the engagement side oil chamber 15 rapidly rises to the first hydraulic pressure P _1, and the hydraulic pressure of the release side oil chamber 16 is increased. Since P _OFF rapidly becomes zero, the lock-up differential pressure ΔP rises greatly from −P ₁ to P ₁ , causing the lock-up clutch 14 to be suddenly engaged, and a shock is thereby generated. In this case, at time t ₄ , the lockup hydraulic control valve 20 is operated to temporarily reduce the hydraulic pressure Pb supplied to the lockup switching valve 30 to the second hydraulic pressure P _{2, and} then operate the lockup switching valve 30. A method of switching the lockup clutch 14 from disengagement (lockup OFF) to engagement (lockup ON) is conceivable. When this method is used, the lock-up differential pressure ΔP is a small fluctuation from −P ₂ to P ₂ , and the lock-up clutch 14 is not suddenly engaged. However, in this case, hydraulic pressure supplied from the stepped accelerator (accelerator opening S becomes the third threshold value S ₁ or more) by operating the lock-up hydraulic control valve 20 to the lockup switching valve 30 Since the lock-up clutch 14 is switched after the Pb is reduced, it takes time to engage the lock-up clutch 14 and it is difficult to start the vehicle 100 smoothly.

Therefore, in the present embodiment, without the engaged state of the lockup clutch 14 at t ₄ when FIG. 6, as shown in step S117 in FIG. 2, and the lock-up clutch 14 and the released state (lockup OFF) The vehicle 100 is started as it is. In addition, when the accelerator opening S is equal to or greater than the third threshold value S ₁ , the lock-up clutch 14 is released (lock-up) if the hydraulic oil temperature is not less than the first threshold value T _1. By starting off, the temperature of the hydraulic oil of the torque converter 10 can be lowered by circulating the hydraulic oil, and the temperature of the hydraulic oil can be maintained at an appropriate temperature (second vehicle starting means).

As described above, the vehicle 100 equipped with the torque converter of the present embodiment has a large hydraulic oil pressure when the temperature of the hydraulic oil is low and the hydraulic oil does not need to be cooled while the vehicle 100 is stopped. Thus, the second hydraulic pressure P ₂ lower than the first hydraulic pressure P ₁ for performing the operation is held, and the flex start can be smoothly performed without causing a shock when the vehicle 100 is started. For this reason, the flex start can be frequently used when the vehicle 100 is started, and the fuel consumption of the vehicle 100 can be improved. Further, the vehicle 100 equipped with the torque converter according to the present embodiment starts with lock-up OFF when the temperature of the hydraulic oil is high, thereby lowering the hydraulic oil temperature of the torque converter 10 by circulating the hydraulic oil. Thus, the oil temperature of the hydraulic oil can be maintained at an appropriate temperature.

  DESCRIPTION OF SYMBOLS 10 Torque converter, 11 Turbine runner, 12 Pump impeller, 13 Stator, 14 Lock-up clutch, 15 Engagement side oil chamber, 16 Release side oil chamber, 17 Engagement side port, 18 Release side port, 19 Front cover, 20 Lock UP hydraulic control valve, 21, 31 control hydraulic chamber, 21a, 31a control pressure input port, 22 first adjustment mechanism, 22a input port, 23 second adjustment mechanism, 24 hydraulic oil supply pipe, 25 communication pipe, 26a first communication Port, 27 Discharge pipe, 27a Discharge port, 28 Second communication pipe, 28a Second communication port, 29, 39 Internal link, 30 Lock-up valve hydraulic control valve, 32 First switching mechanism, 32a Input port, 32b Engagement side Internal flow path, 32c Release side internal flow path, 33 2nd switching mechanism, 34 3rd switching 35, engagement side oil chamber communication pipe, 35a engagement side oil chamber communication port, 36 release side oil chamber communication pipe, 36a release side oil chamber communication port, 37 engagement side discharge pipe, 37a engagement side discharge port, 38 1st communication pipe, 38a Release side discharge port, 40 Oil pump, 42 Regulator, 43 Linear solenoid valve, 44 Solenoid valve, 45 Pressure sensor, 46 Temperature sensor, 47 Speed sensor, 48 Accelerator opening sensor, 50 Control part, 100 vehicles.

Claims (5)

A torque converter including a lock-up clutch that engages and releases according to the hydraulic pressure of the engagement side oil chamber and the hydraulic pressure of the release side oil chamber;
A common hydraulic control valve that adjusts the hydraulic pressure of the hydraulic oil supplied to each of the oil chambers;
A control unit for controlling the operation of the hydraulic control valve;
A vehicle equipped with a torque converter,
The controller is
When the oil temperature of the hydraulic oil is lower than the first threshold, the hydraulic pressure of the hydraulic oil is lower than the first hydraulic pressure for cooling the hydraulic oil by the hydraulic pressure control valve when the vehicle is stopped. holding of the hydraulic pressure, and the first vehicle onset Susumute stage to perform a flex start at the time the vehicle is started,
When the oil temperature of the hydraulic oil is equal to or higher than a first threshold value, the hydraulic pressure of the hydraulic oil is held at the first hydraulic pressure for cooling the hydraulic oil by the hydraulic pressure control valve when the vehicle is stopped. A second vehicle starting means for suppressing a flex start at the time of starting;
I have a,
When the accelerator opening is equal to or greater than a third threshold value when the vehicle is started, the first vehicle starting means controls the hydraulic pressure of the hydraulic oil by the hydraulic control valve for a predetermined time. Holding at a hydraulic pressure, and increasing the hydraulic pressure of the hydraulic oil from the second hydraulic pressure by the hydraulic pressure control valve after the lapse of the predetermined time;
A vehicle equipped with a torque converter. A vehicle equipped with a torque converter according to claim 1,
When the oil temperature of the hydraulic oil is equal to or higher than the first threshold value when the vehicle is stopped, and the oil temperature of the hydraulic oil falls below the first threshold value while the vehicle is stopped, the hydraulic oil is controlled by the hydraulic control valve. Reducing the hydraulic pressure of the second hydraulic pressure to the second hydraulic pressure,
A vehicle equipped with a torque converter. A vehicle equipped with a torque converter according to claim 1 ,
A flow path switching valve for switching the flow of hydraulic oil to each oil chamber,
The first vehicle starting means further controls the operation of the flow path switching valve,
When the accelerator opening is equal to or greater than a third threshold when the vehicle starts, the flow path switching valve is switched so that the hydraulic oil flows to the engagement side oil chamber, and at least the hydraulic control valve Increasing or decreasing the oil pressure in the release side oil chamber to bring the lock-up clutch into a slip state;
A vehicle equipped with a torque converter. A vehicle equipped with a torque converter according to claim 1,
A flow path switching valve for switching the flow of hydraulic oil to each oil chamber,
The second vehicle starting means further controls the operation of the flow path switching valve,
When the accelerator opening is equal to or greater than a third threshold value when the vehicle starts, the hydraulic fluid is switched by the flow path switching valve so that the hydraulic fluid flows into the release side oil chamber, and the hydraulic pressure of the hydraulic fluid is changed to the first hydraulic pressure. Holding at a hydraulic pressure of 1,
A vehicle equipped with a torque converter. A vehicle equipped with a torque converter according to claim 2,
A flow path switching valve for switching the flow of hydraulic oil to each oil chamber,
The control unit further controls the operation of the flow path switching valve,
If the accelerator opening is equal to or greater than a third threshold value when the vehicle is started, the hydraulic fluid is switched to flow into the engagement side oil chamber by the flow path switching valve, and at least the release is performed by the hydraulic pressure control valve. Increasing or decreasing the oil pressure in the side oil chamber , and bringing the lock-up clutch into a slip state;
A vehicle equipped with a torque converter.

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