JP2017026008A - Vehicle control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set a gear change ratio of a continuously variable transmission at a proper gear change ratio at restoration from free run.SOLUTION: In a vehicle control device of a vehicle having an engine, a continuously variable transmission, and a clutch which is arranged between the continuously variable transmission and drive wheels in the middle of a power transmission route, the vehicle control device comprises: gear change ratio setting means which sets a target gear change ratio of the continuously variable transmission corresponding to a vehicle speed; and traveling gear change control means which makes the vehicle inertia-travel in a state that a clutch is released and the supply of fuel into an engine is stopped when a prescribed execution condition is established and the vehicle speed is not lower than a prescribed speed during the traveling of the vehicle, and changes a gear change ratio of the continuously variable transmission to a target gear change ratio which is set by the gear change ratio setting means from a gear change ratio which is detected in advance in a state that the clutch is brought into a slip state and the supply of the fuel into the engine is stopped when the prescribed execution condition is established and the vehicle speed is lower than the prescribed vehicle speed during the traveling of the vehicle.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a vehicle control device.

  2. Description of the Related Art In a vehicle, a belt type CVT with a starting gear (hereinafter referred to as WCVT) provided with an electric oil pump is known as a hydraulic pressure supply source while the engine is stopped. In a so-called free run in which the vehicle is coasting while the engine is stopped, the clutch provided between the WCVT and the drive wheels is released. Thereby, the fuel consumption of the vehicle can be improved.

  Patent Document 1 includes a clutch interposed between a continuously variable transmission and a drive wheel, an electric motor coupled to the drive wheel, and an oil pump that supplies hydraulic pressure to the continuously variable transmission and the clutch. When the clutch is switched from the engaged state to the released state during decelerating regeneration in which regenerative torque is applied to the drive wheels by the electric motor in the equipped vehicle, the clutch is slipped and the speed ratio of the continuously variable transmission is set to the lowest speed ratio or the highest speed. A technique is disclosed in which the clutch is released after the gear ratio is set.

JP 2014-097773 A

  However, in the above-described technique, when the clutch is switched from the engaged state to the released state, the speed ratio of the continuously variable transmission is set to the minimum speed ratio or the maximum speed ratio, so depending on the vehicle speed when returning from free run, There arises a problem that there is a high possibility that the gear ratio is not appropriate.

  The present invention has been made in view of the above, and an object of the present invention is to provide a vehicle control device that can set the speed ratio of the continuously variable transmission to an appropriate speed ratio when returning from free run. There is.

  In order to solve the above-described problems and achieve the above object, a vehicle control device according to the present invention includes an engine, a continuously variable transmission, and a continuously variable transmission and a drive wheel in a power transmission path. In a vehicle control device for controlling a vehicle provided with a clutch provided, a gear ratio setting means for setting a target gear ratio according to a vehicle speed of the vehicle in the continuously variable transmission, and a predetermined value during travel of the vehicle Is satisfied and the vehicle speed is equal to or higher than a predetermined speed, the clutch is disengaged and the fuel supply to the engine is stopped, and the vehicle is coasted. Is satisfied and the vehicle speed is less than the predetermined speed, the clutch is brought into a slip state and the supply of fuel into the engine is stopped, and the gear ratio of the continuously variable transmission is set. Characterized in that the pre-detected gear ratio and a traveling speed change control means for changing the target speed ratio set by the said gear ratio setting means.

  According to the vehicle control device of the present invention, when the vehicle speed of the vehicle is less than the predetermined speed, the clutch is slipped and the continuously variable transmission is rotated, so that the gear ratio of the continuously variable transmission can be detected. Therefore, it is possible to execute the control to change the gear ratio to an appropriate speed ratio, so that the speed ratio of the continuously variable transmission can be set to an appropriate speed ratio when returning from free run.

FIG. 1 is a skeleton diagram schematically showing a target vehicle in the embodiment of the present invention. FIG. 2 is a block diagram illustrating an example of a vehicle control device according to an embodiment of the present invention. FIG. 3 is an engagement table showing the state of each travel mode. FIG. 4 is a hydraulic circuit diagram illustrating an example of the hydraulic control device. FIG. 5 is a flowchart for explaining the free-run control according to the first embodiment of the present invention. FIG. 6A shows a shift map during free run according to the first embodiment, FIG. 6B shows a graph of the target gear ratio according to the vehicle speed during free run according to the first embodiment, It is a figure which shows the graph of the 1st output-shaft rotational speed and 2nd output-shaft rotational speed according to vehicle speed to c). FIG. 7 is a timing chart showing changes in the vehicle state when returning from a free run. FIG. 8A shows a shift map during free run according to the second embodiment in FIG. 8A, and FIG. 8B shows a graph of the target gear ratio according to the vehicle speed during free run according to the second embodiment. FIG. 6C is a graph showing a lower limit value of the input shaft speed, a lower limit value of the first output shaft speed, a target first output shaft speed, and a second output shaft speed according to the vehicle speed. . FIG. 9 is a flowchart for explaining free-run control according to the third embodiment of the present invention.

  Embodiments of the present invention will be described below with reference to the drawings. In all the drawings of the following embodiments, the same or corresponding parts are denoted by the same reference numerals. Further, the present invention is not limited to the embodiments described below.

(1. Vehicle)
First, a vehicle to be controlled by a vehicle control device according to an embodiment of the present invention will be described. FIG. 1 is a skeleton diagram illustrating an example of a target vehicle in the present embodiment.

  As shown in FIG. 1, the vehicle Ve includes an engine 1 as a power source. The engine 1 outputs predetermined power in accordance with the engine speed Ne. The power output from the engine 1 includes a torque converter 2 as a fluid transmission device, an input shaft 3, a forward / reverse switching mechanism 4, a belt-type continuously variable transmission 5 (hereinafter referred to as CVT) or a gear train 6, an output shaft 7, It is transmitted to the drive wheel 11 via the counter gear mechanism 8, the differential gear 9 and the drive shaft 10. A second clutch C <b> 2 is provided on the downstream side of the CVT 5 as a clutch for disconnecting the engine 1 from the drive wheels 11. By releasing the second clutch C2, the CVT 5 and the output shaft 7 are disconnected so that torque cannot be transmitted, and the CVT 5 in addition to the engine 1 is disconnected from the drive wheels 11.

  Specifically, the torque converter 2 includes a pump impeller 2a coupled to the engine 1, a turbine runner 2b disposed opposite to the pump impeller 2a, and a stator 2c disposed between the pump impeller 2a and the turbine runner 2b. Prepare. The inside of the torque converter 2 is filled with oil as a working fluid. The pump impeller 2a rotates integrally with the crankshaft 1a of the engine 1. The input shaft 3 is connected to the turbine runner 2b so as to rotate integrally. The torque converter 2 includes a lock-up clutch. In the engaged state, the pump impeller 2a and the turbine runner 2b rotate integrally. In the opened state, the power output from the engine 1 is transmitted to the turbine runner 2b via the working fluid. Is done. The stator 2c is held by a fixed part such as a case via a one-way clutch.

  A mechanical oil pump (MOP) 41 is connected to the pump impeller 2a via a transmission mechanism such as a belt mechanism. The mechanical oil pump 41 is connected to the crankshaft 1 a via the pump impeller 2 a and is driven by the engine 1. The mechanical oil pump 41 and the pump impeller 2a may be configured to rotate integrally.

The input shaft 3 is connected to a forward / reverse switching mechanism 4. The forward / reverse switching mechanism 4 switches the direction of the torque acting on the drive wheel 11 between the forward direction and the reverse direction when transmitting the engine torque to the drive wheel 11. The forward / reverse switching mechanism 4 is composed of a differential mechanism, and in the example shown in FIG. 1, is constituted by a double pinion type planetary gear mechanism. Its forward-reverse switching mechanism 4, meshes with the sun gear 4S, a ring gear 4R, which is arranged concentrically with the sun gear 4S, a first pinion gear 4P ₁ meshed with the sun gear 4S, a first pinion gear 4P ₁ and ring gear 4R A second pinion gear 4P ₂ and a carrier 4C holding the pinion gears 4P ₁ and 4P _{2 so as} to be capable of rotating and revolving. The drive gear 61 of the gear train 6 is connected to the sun gear 4S so as to rotate integrally. The input shaft 3 is connected to the carrier 4C so as to rotate integrally.

  A first clutch C1 that selectively rotates the sun gear 4S and the carrier 4C integrally is provided. By engaging the first clutch C1, the entire forward / reverse switching mechanism 4 rotates integrally. Further, a brake B1 that selectively fixes the ring gear 4R so as not to rotate is provided. The first clutch C1 and the brake B1 are hydraulic.

  For example, when the first clutch C1 is engaged and the brake B1 is released, the sun gear 4S and the carrier 4C rotate integrally. That is, the input shaft 3 and the drive gear 61 rotate integrally. Further, when the first clutch C1 is released and the brake B1 is engaged, the sun gear 4S and the carrier 4C rotate in opposite directions. That is, the input shaft 3 and the drive gear 61 rotate in opposite directions.

  In the vehicle Ve, a CVT 5 that is a continuously variable transmission and a gear train 6 that is a stepped transmission unit are provided in parallel. As a power transmission path between the input shaft 3 and the output shaft 7, a power transmission path via the CVT 5 (hereinafter referred to as a first path) and a power transmission path via the gear train 6 (hereinafter referred to as a second path) are arranged in parallel. Is formed.

  The CVT 5 includes a primary pulley 51 that rotates integrally with the input shaft 3 and the input shaft rotation speed Nin, a secondary pulley 52 that rotates integrally with the secondary shaft 54, and a belt 53 wound around a V groove formed in the pair of pulleys 51, 52. Is provided. The input shaft 3 is a primary shaft. Since the winding diameter of the belt 53 changes by changing the V groove width of each pulley 51, 52, the transmission ratio γ of the CVT 5 can be continuously changed. The gear ratio γ of the CVT 5 continuously changes within the range from the maximum gear ratio γmax (gear is the lowest) to the minimum gear ratio γmin (gear is the highest).

The primary pulley 51 includes a fixed sheave 51a that is integrated with the input shaft 3, a movable sheave 51b that is movable in the axial direction on the input shaft 3, and a primary hydraulic cylinder 51c that applies thrust to the movable sheave 51b. The sheave surface of the fixed sheave 51a and the sheave surface of the movable sheave 51b face each other to form a V groove of the primary pulley 51. The primary hydraulic cylinder 51c is disposed on the back side of the movable sheave 51b. Hydraulic pressure in the primary hydraulic cylinder 51c (hereinafter, primary as pressure) by P _in, the thrust for moving the movable sheave 51b toward the fixed sheave 51a side is generated.

The secondary pulley 52 includes a fixed sheave 52a integrated with the secondary shaft 54, a movable sheave 52b that can move in the axial direction on the secondary shaft 54, and a secondary hydraulic cylinder 52c that applies thrust to the movable sheave 52b. The sheave surface of the fixed sheave 52a and the sheave surface of the movable sheave 52b face each other to form a V groove of the secondary pulley 52. The secondary hydraulic cylinder 52c is disposed on the back side of the movable sheave 52b. Hydraulic pressure in the secondary hydraulic cylinder 52c (hereinafter, the secondary pressure) by P _out, thrust for moving the movable sheave 52b toward the fixed sheave 52a side is generated.

  The second clutch C <b> 2 is provided between the secondary shaft 54 and the output shaft 7, and can selectively disconnect the CVT 5 from the output shaft 7. For example, when the second clutch C2 is engaged, the CVT 5 and the output shaft 7 are connected so as to be able to transmit power, and the secondary shaft 54 and the output shaft 7 rotate integrally. That is, the rotational speed Nout1 of the secondary pulley 52 on the upstream side of the second clutch C2 and the output shaft rotational speed Nout2 on the downstream side of the second clutch C2 coincide (Nout1 = Nout2). On the other hand, when the second clutch C2 is released, the secondary shaft 54 and the output shaft 7 are disconnected so that torque cannot be transmitted, and the engine 1 and the CVT 5 are disconnected from the drive wheels 11.

  The second clutch C2 is hydraulic. The engaging elements of the second clutch C2 are configured to frictionally engage with each other by a hydraulic actuator. Therefore, when the engagement elements of the second clutch C2 are frictionally engaged with each other in a half-engaged state, the second clutch C2 can be brought into a slip state. In this case, the torque transmitted between the CVT 5 and the output shaft 7 is relatively small.

  An output gear 7a and a driven gear 63 are attached to the output shaft 7 so as to rotate integrally. The output gear 7a meshes with the counter driven gear 8a of the counter gear mechanism 8 that is a reduction mechanism. The counter drive gear 8 b of the counter gear mechanism 8 meshes with the ring gear 9 a of the differential gear 9. Left and right drive wheels 11 and 11 are connected to the differential gear 9 via left and right drive shafts 10 and 10.

  The gear train 6 includes a drive gear 61 that rotates integrally with the sun gear 4 </ b> S of the forward / reverse switching mechanism 4, a counter gear mechanism 62, and a driven gear 63 that rotates integrally with the output shaft 7. The gear train 6 is a reduction mechanism, and the gear ratio (gear ratio) of the gear train 6 is set to a predetermined value larger than the maximum gear ratio γmax of the CVT 5. The gear ratio of the gear train 6 is a fixed gear ratio. The vehicle Ve is configured to be able to transmit torque from the engine 1 to the drive wheels 11 via the gear train 6 when starting. The gear train 6 functions as a starting gear.

  The drive gear 61 meshes with the counter driven gear 62 a of the counter gear mechanism 62. The counter gear mechanism 62 includes a counter driven gear 62 a, a counter shaft 62 b, and a counter drive gear 62 c that meshes with the driven gear 63. A counter driven gear 62a is attached to the counter shaft 62b so as to rotate integrally. The counter shaft 62 b is disposed in parallel with the input shaft 3 and the output shaft 7. The counter drive gear 62c is configured to be rotatable relative to the counter shaft 62b.

  Further, a meshing engagement device (hereinafter referred to as a dog clutch) S1 for selectively rotating the counter shaft 62b and the counter drive gear 62c integrally is provided. The dog clutch S1 includes a pair of meshing engagement elements 64a and 64b and a sleeve 64c movable in the axial direction. The first engagement element 64a is a hub that is spline-fitted to the counter shaft 62b. The first engagement element 64a and the counter shaft 62b rotate integrally. The second engagement element 64b is coupled to rotate integrally with the counter drive gear 62c. That is, the second engagement element 64b rotates relative to the counter shaft 62b. The dog clutch S1 is engaged when the spline teeth formed on the inner peripheral surface of the sleeve 64c mesh with the spline teeth formed on the outer peripheral surfaces of the engagement elements 64a and 64b. By engaging the dog clutch S1, the drive gear 61 and the driven gear 63 (second path) are connected so that torque can be transmitted. When the meshing between the second engagement element 64b and the sleeve 64c is released, the dog clutch S1 is released. By releasing the dog clutch S1, the space between the drive gear 61 and the driven gear 63 (second path) is blocked so that torque transmission is impossible. The dog clutch S1 is a hydraulic type, and the sleeve 64c is moved in the axial direction by a hydraulic actuator.

(2. Vehicle control device)
FIG. 2 is a functional block diagram schematically showing the vehicle control device of the present embodiment. The vehicle control device is configured by an electronic control device (hereinafter, ECU: Electronic Control Unit) 100 that controls the vehicle Ve. The ECU 100 is mainly composed of a microcomputer having a CPU (Central Processing Unit), a RAM (Random Access Memory), and the like. ECU 100 performs a calculation using the input data and data stored in advance, and outputs the calculation result as a command signal.

  The ECU 100 receives signals from various sensors 31 to 38. The vehicle speed sensor 31 detects the vehicle speed V. The input shaft rotational speed sensor 32 detects the rotational speed (hereinafter referred to as input shaft rotational speed) Nin of the input shaft 3. Since the input shaft 3 and the turbine runner 2b rotate integrally, the input shaft rotational speed sensor 32 detects the rotational speed (hereinafter referred to as turbine rotational speed) Nt of the turbine runner 2b. The input shaft rotational speed Nin and the turbine rotational speed Nt coincide. The first output shaft rotational speed sensor 33 detects the rotational speed of the secondary shaft 54 (hereinafter referred to as the first output shaft rotational speed) Nout1. The second output shaft rotational speed sensor 34 detects the rotational speed of the output shaft 7 (hereinafter referred to as the second output shaft rotational speed) Nout2. The first output shaft rotation speed Nout1 is before the second clutch C2 (upstream side), and the second output shaft rotation speed Nout2 is after the second clutch C2 (downstream side). The engine speed sensor 35 detects the rotation speed (hereinafter referred to as engine speed) Ne of the crankshaft 1a. The accelerator opening sensor 36 detects an operation amount of an accelerator pedal (not shown). The brake stroke sensor 37 detects an operation amount of a brake pedal (not shown). The shift position sensor 38 detects the position of a shift lever (not shown). Further, the ECU 100 can detect (calculate) the transmission ratio γ (= Nin / Nout1) of the CVT 5 by dividing the input shaft rotational speed Nin by the first output shaft rotational speed Nout1 during the rotation of the CVT 5.

  ECU 100 includes a travel control unit 101, a return control unit 102, a gear ratio setting unit 103, and a determination unit 104.

  The travel control unit 101 controls the vehicle Ve to a plurality of travel modes. An example of the running mode is free run. The free run is a travel mode in which the vehicle Ve is coasted by releasing the second clutch C2, which is an engine disconnecting clutch, and automatically stopping the engine 1. The ECU 100 executes free run control when a predetermined execution condition is satisfied, and shifts the vehicle Ve from normal running to free run. Further, when a predetermined return condition is satisfied during the free run, the return control unit 102 executes control (return control) for returning from the free run to the normal travel. By returning to the normal running from the free run, the vehicle can run with the power output by the engine 1. A transmission ratio setting unit 103 as a transmission ratio setting unit sets a transmission ratio γ of the CVT 5. The determination unit 104 determines whether an execution condition and a return condition are satisfied.

  The ECU 100 outputs a command signal to the engine 1 to control the fuel supply amount, intake air amount, fuel injection, ignition timing, and the like. Further, the ECU 100 outputs a hydraulic pressure command signal to the hydraulic pressure control device 200 to control the shift operation of the CVT 5 and the operation of each engagement device such as the first clutch C1. The hydraulic control device 200 supplies hydraulic pressure to the hydraulic cylinders 51c and 52c of the CVT 5 and the respective engagement devices, that is, the hydraulic actuators of the first clutch C1, the second clutch C2, the brake B1, and the dog clutch S1. The ECU 100 controls the hydraulic control device 200 to execute control for switching the power transmission path between the first path and the second path, shift control of the CVT 5, control for switching to various travel modes, and the like.

(2-1. Driving mode)
FIG. 3 is an engagement table showing various travel modes. In FIG. 3, with respect to the state of the engagement device, the engagement state is represented by “◯” and the release state is represented by “X”. Regarding the position of the shift lever, the drive position is represented by “D”, the reverse position is represented by “R”, the parking position is represented by “P”, and the neutral position is represented by “N”.

  The driving mode is divided into normal time and free run. The normal driving (D) includes three driving modes: start, medium speed, and high speed. When starting, the first clutch C1 and the dog clutch S1 are engaged, and the second clutch C2 and the brake B1 are released. The power transmission path at the start is set to the second path via the gear train 6. When the vehicle speed V rises to some extent after the start, the travel mode is changed from the start to the medium speed by performing the switching control for releasing the first clutch C1 and engaging the second clutch C2. At medium speed, the second clutch C2 and the dog clutch S1 are engaged, and the first clutch C1 and the brake B1 are released. The power transmission path at medium speed is set to the first path via the CVT 5. That is, the power transmission path is switched from the second path to the first path when shifting from the start to the medium speed. Further, the grip change control between the first clutch C1 and the second clutch C2 is clutch-to-clutch control that gradually changes the transmission torque capacity. When the vehicle speed V further increases during the medium speed travel, the dog clutch S1 is released and the travel mode shifts from the medium speed to the high speed. At high speed, the second clutch C2 is engaged, and the first clutch C1, the brake B1, and the dog clutch S1 are released. At the time of transition from medium speed to high speed, path switching is not performed, and the power transmission path remains the first path.

  At the time of reverse travel (R), the brake B1 and the dog clutch S1 are engaged, and the first clutch C1 and the second clutch C2 are released, so that the power transmission path is set to the second path via the gear train 6. When the shift position is “N” or “P”, the dog clutch S1 is engaged, and the first clutch C1, the second clutch C2, and the brake B1 are released.

  The free run includes medium speed and high speed. At the free running medium speed, the dog clutch S1 is engaged, and the first clutch C1, the second clutch C2, and the brake B1 are released. At the free-run high speed, the first clutch C1, the second clutch C2, the brake B1, and the dog clutch S1 are released. The power transmission path during free run is set to the first path. For example, when shifting from normal running to free run, there are cases where the normal speed (D) is shifted from the medium speed to the free run medium speed, and where the normal speed (D) is shifted from the high speed to the free run high speed. included. While traveling at a normal medium speed (D), the second clutch C2 is released to shift to a free-run medium speed. While traveling at a normal high speed (D), the second clutch C2 is released to shift to a free-run high speed. Further, when returning from normal running to normal running, the second clutch C2 is engaged. By engaging the second clutch C2 during the free-running medium speed, the vehicle returns to the normal medium speed (D). By engaging the second clutch C2 at the time of free-run high speed, the normal high speed (D) is restored.

(2-2. Hydraulic circuit)
FIG. 4 is a hydraulic circuit diagram illustrating an example of the hydraulic control device 200. The hydraulic control device 200 includes a mechanical oil pump 41 driven by an engine (Eng) 1 and an electric oil pump 43 driven by an electric motor (M) 42 as hydraulic supply sources. A battery (not shown) is electrically connected to the electric motor 42. Each pump 41, 43 sucks oil stored in the oil pan and pumps it to the first oil passage 201. Oil discharged from the electric oil pump 43 is supplied to the first oil passage 201 via the second oil passage 202. The first oil passage 201 and the second oil passage 202 are connected via a check valve. When the oil pressure in the first oil passage 201 is higher than the oil pressure in the second oil passage 202, the check valve is closed. When the oil pressure in the first oil passage 201 is lower than the oil pressure in the second oil passage 202, the check valve opens. For example, during the free run, the engine 1 stops and the mechanical oil pump 41 cannot be driven, so that the hydraulic oil is supplied into the first oil passage 201 by driving the electric oil pump 43.

The hydraulic control device 200 adjusts the hydraulic pressure of the first oil passage 201 to the first line pressure P _L1, and adjusts the oil discharged from the first pressure regulating valve 211 to the second line pressure P _L2 . second pressure regulating valve 212, regulates the primary pressure P _in the first pressure reducing valve for pressurizing regulated to a predetermined modulator pressure P _M the first line pressure P _L1 as a source pressure (modulator valve) 213, the first line pressure P _L1 as source pressure A second pressure reducing valve (transmission ratio control valve) 214 to be pressurized, and a third pressure reducing valve (clamping pressure control valve) 215 to regulate the secondary pressure P _out using the first line pressure P _L1 as a source pressure. The first pressure regulating valve 211 is controlled based on the control pressure output from the linear solenoid valve (not shown) so as to generate the first line pressure P _L1 according to the running state. Further, the oil regulated to the second line pressure P _L2 by the second pressure regulating valve 212 is supplied to the torque converter 2. The oil discharged from the second pressure regulating valve 212 is supplied to a lubrication system such as a meshing portion between the gears.

  A plurality of linear solenoid valves SL1, SL2, SL3, SLP, and SLS are connected to the first pressure reducing valve 213 through a third oil passage 203. Each of the linear solenoid valves SL1, SL2, SL3, SLP, and SLS is independently excited, de-energized, and current controlled by the ECU 100 to adjust the hydraulic pressure according to the hydraulic pressure command signal.

The linear solenoid valve SL1 regulates the modulator pressure P _M to the first clutch pressure P _C1 corresponding to the hydraulic pressure command signal and supplies it to the first clutch C1. The linear solenoid valve SL2 adjusts the modulator pressure P _M to the second clutch pressure P _C2 corresponding to the hydraulic pressure command signal, and supplies it to the second clutch C2. The linear solenoid valve SL3 is by regulating the hydraulic supply pressure P _bs corresponding to the modulator pressure P _M in the hydraulic pressure command signal is supplied to the dog clutch S1 and the brake B1. The linear solenoid valve SL3 is connected to the dog clutch S1 and the brake B1 via the switching valve 206. The switching valve 206 operates mechanically or electrically to switch the oil path based on the operation of the shift lever. When the shift lever is in the “D” position, the supply hydraulic pressure P _bs is supplied to the dog clutch S1. When the shift lever is in the “R” position, the supply hydraulic pressure P _bs is supplied to the dog clutch S1 and the brake B1. When the shift lever is in the “P” or “N” position, the supply hydraulic pressure P _bs is supplied to the dog clutch S1.

The linear solenoid valve SLP regulates the signal pressure P _SLP using the modulator pressure P _M as a source pressure, and outputs the signal pressure P _SLP to the second pressure reducing valve 214. The linear solenoid valve SLS regulates the signal pressure P _SLS using the modulator pressure P _M as a source pressure, and outputs the signal pressure P _SLS to the third pressure reducing valve 215.

A primary hydraulic cylinder 51 c is connected to the second pressure reducing valve 214 via a fourth oil passage 204. The second pressure reducing valve 214 and the fourth oil passage 204 form a transmission ratio control circuit for the CVT 5. The second pressure reducing valve 214 is a valve for controlling the gear ratio γ of the CVT 5. The second pressure reducing valve 214 controls the amount of oil (hydraulic pressure) supplied to the primary hydraulic cylinder 51c. Second pressure reducing valve 214 by regulating the primary pressure P _in the first line pressure P _L1 as an original pressure supplied to the primary hydraulic cylinder 51c. Second pressure reducing valve 214, pressure regulating the primary pressure P _in based on a signal pressure P _SLP inputted from the linear solenoid valve SLP. ECU100 regulates the primary pressure P _in by controlling the hydraulic pressure command signal to be output to the linear solenoid valve SLP. By primary pressure P _in changes, V groove width of the primary pulley 51 is changed. ECU100 by controlling the primary pressure P _in, to control the γ gear ratio of CVT5.

Specifically, for example, in the upshift control, increasing the primary pressure P _in narrowing the V groove width of the primary pulley 51 continuously. During the upshift, the transmission ratio γ of the CVT 5 is continuously reduced. In downshift control, reduce the primary pressure P _in, to increase the V groove width of the primary pulley 51 continuously. During downshifting, the gear ratio γ of the CVT 5 increases continuously. During downshifting, the oil in the primary hydraulic cylinder 51c was drained from the drain port of the second pressure reducing valve 214 reduces the primary pressure P _in. In the target gear ratio control executed during coasting pressure regulates the primary pressure P _in the speed ratio of CVT5 gamma is the gear ratio of the target. On the other hand, when to maintain the gear ratio in the coasting by the second pressure reducing valve 214 closes the fourth oil passage 204, to maintain the primary pressure P _in a predetermined value. Even if you wish to maintain the gear ratio gamma, there is a possibility that the primary pressure P _in is reduced by the oil leakage or the like. In this case, the second pressure reducing valve 214 is opened by a predetermined flow path cross-sectional area so that the first oil path 201 and the fourth oil path 204 communicate with each other, and a part of the first line pressure P _L1 is transferred to the primary hydraulic cylinder 51c. You may supply.

A secondary hydraulic cylinder 52 c is connected to the third pressure reducing valve 215 via a fifth oil passage 205. The third pressure reducing valve 215 and the fifth oil passage 205 form a clamping pressure control circuit for the CVT 5. The third pressure reducing valve 215 is a valve that controls the belt clamping pressure. The third pressure reducing valve 215 controls the amount of oil (hydraulic pressure) supplied to the secondary hydraulic cylinder 52c. The third pressure reducing valve 215 by regulating the secondary pressure P _out of the first line pressure P _L1 as an original pressure supplied to the secondary hydraulic cylinder 52c. The third pressure reducing valve 215 regulates the secondary pressure P _out based on the signal pressure P _SLS input from the linear solenoid valve SLS. The ECU 100 adjusts the secondary pressure _Pout by controlling a hydraulic pressure command signal output to the linear solenoid valve SLS. By secondary pressure P _out is changed, a change in belt clamping pressure CVT5. ECU 100 controls the clamping pressure of CVT 5 by controlling secondary pressure P _out .

Specifically, for example, the third pressure reducing valve 215, when the signal pressure P _SLS is high, operates to increase the secondary pressure P _out of the secondary hydraulic cylinder 52c. That is, the ECU 100 increases the belt clamping pressure by increasing the hydraulic pressure command value to the linear solenoid valve SLS. The belt clamping pressure is a force for clamping the belt 53 between the V grooves of the pulleys 51 and 52. The belt clamping pressure causes a frictional force between the pulleys 51 and 52 and the belt 53 in the rotating CVT 5. That is, tension is generated in the belt 53 in a state of being wound around the V grooves of the pulleys 51 and 52 by the belt clamping pressure. Therefore, in the secondary hydraulic cylinder 52c, it is necessary to generate a belt clamping pressure that prevents the belt 53 from slipping between the pulleys 51 and 52. As required belt clamping pressure occurs, the third pressure reducing valve 215 to the pressure regulation control secondary pressure P _out. When belt slip does not occur, such as when the CVT 5 stops rotating, the necessary belt clamping pressure is reduced. In this case, the oil in the secondary hydraulic cylinder 52c is discharged from the drain port of the third pressure reducing valve 215, and the secondary pressure _Pout is reduced.

(First embodiment)
Next, a free run control method for the vehicle Ve configured as described above will be described. FIG. 5 is a flowchart for explaining the free run control method according to the first embodiment, and FIG. 6 shows a shift map during free run, and FIG. 6B shows the vehicle speed during free run. (C) is a graph showing the first output shaft rotation speed and the second output shaft rotation speed according to the vehicle speed. The ECU 100 executes the control flow shown in FIG. 5 from the state where the vehicle Ve is controlled to the normal running state. In the normal travel state, the vehicle Ve is traveled forward by the power of the engine 1 by engaging the second clutch C2.

  As shown in FIG. 5, in step ST1, the travel control unit 101 detects the vehicle speed V of the vehicle Ve and the speed ratio γ of the CVT 5. Here, in the first embodiment, the travel control unit 101 as the travel shift control means detects the speed ratio γ of the CVT 5 before stopping the engine 1. This is because after the second clutch C2 is released and the engine 1 is stopped, the CVT 5 stops rotating and the gear ratio γ of the CVT 5 cannot be detected. Thereafter, the process proceeds to step ST2.

  Thereafter, in step ST2, the determination unit 104 determines whether or not the accelerator is off based on a signal from the accelerator opening sensor 36 while the vehicle Ve is traveling normally. When the accelerator is off (step ST2: Yes), the process proceeds to step ST3, and the determination unit 104 determines whether the brake is off based on a signal from the brake stroke sensor 37. In steps ST2 and ST3, the determination unit 104 determines whether or not a free-run execution condition that is a condition for starting free-run is satisfied. Here, the free run execution condition is when the accelerator is off and the brake is off while the vehicle Ve is traveling normally. Therefore, when the determination unit 104 determines that the accelerator is not off (step ST2: No) or determines that the brake is not off (step ST3: No), the control routine ends. That is, the normal running state is continued without shifting the vehicle Ve to the free-run state. Note that the accelerator is off (accelerator Off) means that the accelerator pedal is returned, for example, when the driver lifts his / her foot from the accelerator pedal. The accelerator is turned off when the accelerator opening is zero (0). Also, the brake is off (brake off) means that the brake pedal has been returned, such as when the driver lifts his / her foot from the brake pedal. The brake is turned off when the brake pedal force and the brake stroke amount are zero (0). If the determination unit 104 determines that the accelerator is off (step ST2: Yes) and the brake is also off (step ST3: Yes), the process proceeds to step ST4.

In step ST4, the determination unit 104 determines whether or not the detected vehicle speed is _{equal to} or higher than a predetermined vehicle speed V _C2 that is a control mode determination threshold value. The predetermined vehicle speed V _C2 is determined for each vehicle specification and engine 1. In the first embodiment, as shown in the shift map of FIG. 6A, the minimum shift line (coast line) when the accelerator opening is 0 (Acc = 0%) during normal travel. A lower limit vehicle speed at which coasting can be performed at a gear ratio γmin is defined as a predetermined vehicle speed V _C2 . In other words, the predetermined vehicle speed V _C2 is the lowest vehicle speed at which the vehicle can travel at the minimum gear ratio, and is the vehicle speed at which the coast line deviates from the line with the minimum gear ratio γmin and a downshift is started. In FIG. 6, the vehicle speed V _L is the lower limit of the vehicle speed V at which free run can be performed, and the vehicle speed V _H is the upper limit of the vehicle speed V at which free run can be performed. And as shown in FIG. 5, when the determination part 104 determines with the vehicle speed of the vehicle Ve being more than predetermined vehicle speed V _C2 (step ST4: Yes), it transfers to step ST5.

  In step ST5, the travel control unit 101 performs release control of the second clutch C2 to release the second clutch C2, and then proceeds to step ST6. In step ST <b> 6, the traveling control unit 101 stops combustion inside the engine 1 and automatically stops the engine 1. The control in steps ST5 and ST6 is free run start control. Thereafter, the process proceeds to step ST7.

In step ST7, traveling control unit 101 maintains the gear ratio γ of CVT 5 at the gear ratio detected in step ST1. Note that steps ST6 and ST7 may be executed simultaneously. In this case, the gear ratio γ of the CVT 5 is fixed at the start of the free run. While the vehicle Ve is free running, the traveling control unit 101 maintains the V groove width of each of the pulleys 51 and 52 at the V groove width at the start of the free run. In this case, the ratio (sheave thrust ratio) between the thrust of the primary pulley 51 and the thrust of the secondary pulley 52 is maintained. That is, the travel control unit 101 controls the hydraulic pressure ratio (hydraulic balance) between the primary pressure P _in and the secondary pressure P _out so that the V groove width of each pulley 51, 52 does not change. Therefore, the traveling control unit 101 executes control (transmission ratio maintaining control) for maintaining the hydraulic ratio in the state at the start of free run. Thereby, the gear ratio γ of the CVT 5 is maintained at the value at the start of the free run. In this state, since the rotation of the CVT 5 is stopped, the V groove widths of the pulleys 51 and 52 can be maintained in the state at the start of the free run even if the hydraulic pressure is lower than the hydraulic pressure before the start of free run. Furthermore, it transfers to step ST8 and the traveling control part 101 detects the vehicle speed V, when the vehicle Ve is free-running. Thereafter, the process proceeds to step ST9.

In step ST9, the determination unit 104 determines whether or not the vehicle speed V detected by the travel control unit 101 is less than a predetermined vehicle speed V _C2 . When the determination unit 104 determines that the vehicle speed V is less than the predetermined vehicle speed V _C2 , the process proceeds to step ST10.

  In step ST10, the traveling control unit 101 switches the control for the second clutch C2 from the release control to the slip control. Here, as shown in the graph of FIG. 6C, the second output shaft rotational speed Nout2 of the output shaft 7 on the downstream side of the second clutch C2 during the free run is proportional to the vehicle speed V. By the slip control for the second clutch C2, the torque transmitted from the drive wheel 11 through the output shaft 7 is weakened by the second clutch C2, and the upstream secondary pulley 52 is rotated at a predetermined first output shaft rotational speed Nout1tgt. . At this time, the predetermined first output shaft rotational speed Nout1tgt is controlled to be lower than the second output shaft rotational speed Nout2 of the output shaft 7 by the target slip rotational speed. In other words, the second clutch C2 is controlled to slip by the target slip rotation speed so that the rotation speed of the secondary pulley 52 becomes the predetermined first output shaft rotation speed Nout1tgt. Along with the rotation of the secondary pulley 52, torque is transmitted from the CVT 5 to the engine 1 through the input shaft 3 and the torque converter 2. As a result, the engine 1 starts to rotate at an extremely low speed in a state where the supply of fuel is stopped. Thereafter, the process proceeds to step ST11.

In step ST11, the travel control unit 101 performs target gear ratio control. In the target speed ratio control, as shown in the graph of the target speed ratio according to the vehicle speed in FIG. 6B, the speed ratio setting unit 103 sets the target speed ratio between the minimum speed ratio γmin and the maximum speed ratio γmax. Set γtgt. Note that the target gear ratio data corresponding to the vehicle speed V shown in FIG. 6B is stored in the gear ratio setting unit 103. Here, the target gear ratio γtgt is preferably a gear ratio calculated based on the coast line shown in FIG. 6A in consideration of responsiveness at the time of free-run return. Then, the travel control unit 101 as the travel speed control means executes the shift control of the CVT 5 and changes the speed ratio γ of the CVT 5 toward the target speed ratio γtgt. For example, if you run a downshift control to increase toward the target speed ratio γtgt the gear ratio gamma, traveling control unit 101, by lowering the primary pressure P _in and discharge the oil in the primary hydraulic cylinder 51c, The V groove width of the primary pulley 51 is increased. As a result, the gear ratio γ of the CVT 5 increases toward the target gear ratio γtgt. Conversely, when upshift control is performed toward the target gear ratio γtgt, the reverse control may be performed. As shown in FIGS. 6A, 6B, and 6C, in a state where the predetermined first output shaft rotational speed Nout1tgt does not change according to the vehicle speed V equal to or lower than the predetermined vehicle speed V _C2 , The input shaft rotational speed Nin of 3 is the rotational speed corresponding to the shift of the CVT 5 to the target speed ratio γtgt. Thereafter, the process proceeds to step ST12. In step ST12, the traveling control unit 101 detects the vehicle speed V as in step ST8.

Subsequently, in step ST13, the determination unit 104 determines whether the vehicle speed V detected in step ST12 is equal to or higher than a speed (V _C2 + V _hys ) obtained by adding a preset hysteresis speed V _hys to the predetermined vehicle speed V _C2 . Determine whether or not. Here, the criterion for determination by the determination unit 104 is set to a speed obtained by increasing the hysteresis speed V _hys to the predetermined vehicle speed V _C2 between switching control of the second clutch C2 and slip control. This is to prevent hunting that is repeated. When the determination unit 104 determines that the vehicle speed V is less than the total speed of the hysteresis speed V _hys and the predetermined vehicle speed V _C2 (step ST13: No), the process proceeds to step ST14.

  In step ST14, the determination unit 104 determines whether or not a condition for returning from free run to normal running (free run return condition) is satisfied. The free-run return condition includes a case where the accelerator is on (accelerator On) and a case where the brake is on (brake On). When there is a free-run return instruction by a driver request such as accelerator On or brake On, the free-run return condition is satisfied (step ST14: Yes), and the process proceeds to step ST15. Note that the free-run return condition may include power consumption, the state of charge (SOC) of the battery, the oil temperature of the transmission, and the like. These are system-required free-run return instructions. On the other hand, when the free-run return condition is not satisfied (step ST14: No), the ECU 100 returns to step ST11 and repeats the processes of steps ST11 to ST13. Here, accelerator On means that the driver has stepped on the accelerator pedal. When the accelerator opening is larger than zero, the accelerator is On. Brake On means that the driver has depressed the brake pedal. The brake is turned on when the brake depression force and the brake stroke amount are larger than zero.

  When moving to step ST15, the return control unit 102 restarts the engine 1. Subsequently, when the process proceeds to step ST16, the return control unit 102 engages the second clutch C2. By executing steps ST15 and ST16, the second clutch C2 is engaged and the engine 1 is driven, so the free-run state is terminated and the return control is completed. That is, returning from the free run means that the ECU 100 restarts the engine 1 and engages the second clutch C2 during the free run of the vehicle Ve. The control routine is completed by returning to normal running from free run.

  The control in steps ST14 to ST16 is control (return control) for returning from free run to normal travel. The return control unit 102 restarts the engine 1 to restart the rotation of the CVT 5 before engaging the second clutch C2, and executes the shift control (downshift) of the CVT 5. That is, the timing for restarting the engine 1 and the timing for engaging the second clutch C2 are different. Then, after the engine 1 is restarted and the downshift control of the CVT 5 is started, the second clutch C2 is engaged.

In step ST4, when the vehicle speed V is less than the predetermined vehicle speed V _C2 (step ST4: No), the process proceeds to step ST17, and the slip control for the second clutch C2 is performed by the travel control unit 101 in the same manner as in step ST10. Is done. Since the engine 1 is driven at this time, the state shown in FIG. 6 is shifted down from the highest gear, and then the process proceeds to step ST18.

  In step ST18, the supply of fuel to the engine 1 is stopped, and the engine 1 enters a non-independent state. At this time, since the slip control is performed on the second clutch C2, the torque from the drive wheel 11 is weakened via the second clutch C2 in the slip state, and the engine 1 is passed through the CVT 5 and the input shaft 3. Is transmitted. As a result, the engine 1 continues to rotate at an extremely low rotational speed. Thereafter, the process proceeds to step ST11.

In step ST9, when the vehicle speed V is equal to or higher than the predetermined vehicle speed V _C2 (step ST9: No), the process proceeds to step ST19, and whether or not the free-run return condition is satisfied by the determination unit 104 as in step ST14. Is determined. If the free-run return condition is not satisfied (step ST19: No), the process returns to step ST7, and steps ST7 to ST9 are repeatedly executed. On the other hand, when the free-run return condition is satisfied (step ST19: Yes), the process proceeds to step ST15 and the return control is performed.

Furthermore, when the determination unit 104 determines in step ST13 that the vehicle speed V is equal to or higher than the total speed of the hysteresis speed V _hys and the predetermined vehicle speed V _C2 (step ST13: Yes), the process proceeds to step ST20. In this case, the vehicle speed V increases due to various causes. Further, at the time of shifting to step ST20, slip control is performed on the second clutch C2 by the traveling control unit 101. Therefore, in step ST20, the travel control unit 101 switches to the release control for the second clutch C2. Thereafter, the process proceeds to step ST7, and steps ST7 to ST13 and step ST19 are repeatedly executed as necessary.

According to the first embodiment of the present invention described above, in the vehicle Ve equipped with the WCVT, when the vehicle speed V becomes equal to or higher than the predetermined vehicle speed V _C2 when or after the free-run execution condition is satisfied, the second This is a case where the vehicle speed V is lowered during the free run by performing the release control on the clutch C2 and performing the slip control on the second clutch C2 when the vehicle speed is lower than the predetermined vehicle speed V _C2. Since the CVT 5 can be rotated to change the speed, the responsiveness at the time of free-run return can be improved and drivability can be ensured.

  Further, according to the knowledge of the present inventor, when shifting the CVT 5 before the engagement of the second clutch C2 at the time of return from the free run, there are the following problems. FIG. 7 is a timing chart for explaining this problem.

As indicated by the portion surrounded by the broken line in FIG. 7, when the free-run return instruction is detected (time t ₄ ) and the free-run return control is started, the return control unit 102 executes the engine start control and restarts the engine 1. The engine 1 is started and becomes in a self-sustaining state (time t ₅ ). In this case, the engine speed Ne is a self-supporting speed. When the engine 1 becomes self-sustaining, the engine torque starts to be output by fuel supply / ignition, and the engine speed Ne starts to increase and the CVT 5 starts to rotate. Therefore, the input shaft speed Nin and the first output shaft speed Nout1 Begins to rise from zero. Therefore, at time t ₅ , the primary pressure P _in and the secondary pressure P _out of the pulleys 51 and 52 are increased so that the belt 53 of the CVT ₅ does not slip. When engine start control is executed after time t ₄ and CVT 5 begins to rotate, primary pulley 51 and secondary pulley 52 begin to rotate at the same time, so input shaft speed Nin (= turbine speed Nt) The output shaft speed Nout1 starts to rise from zero at the same time.

Further, from time t5, when the return control unit 102 starts the downshift control of the CVT ₅ , the input shaft rotational speed Nin starts to increase. Furthermore, the return control unit 102 controls the second clutch pressure P _C2 to a hydraulic pressure within a range in which the second clutch C2 does not generate a transmission torque capacity while the CVT 5 is being downshifted. In this case, the second clutch pressure P _C2 is maintained at a predetermined hydraulic pressure greater than zero. When the gear ratio γ of the CVT 5 reaches the target gear ratio γtgt, the downshift control is completed (time t ₆ ). At time t _6, the speed ratio of CVT5 gamma becomes the target speed ratio Ganmatgt, since the first output shaft rotational speed Nout1 is synchronized with the second output shaft rotating speed Nout2, engagement ECU100 from time t ₆ of the second clutch C2 Start the joint control. During time t _{5 to} t ₆ , CVT ₅ is being downshifted, and the actual gear ratio γact of CVT 5 continuously increases.

  In the free-run return control as described above, it is necessary to perform the shift in the CVT 5 as soon as possible from the viewpoint of responsiveness. For this reason, the electric oil pump 43 has a problem that large power consumption is required and the size of the electric oil pump 43 is increased, which increases the cost. On the other hand, according to the first embodiment described above, slip control is performed on the second clutch C2 during the free run, thereby rotating the CVT 5 to rotate the gear ratio toward the target gear ratio γtgt. Therefore, while ensuring responsiveness, it is possible to suppress power consumption of the electric oil pump 43 to suppress an increase in size and to reduce costs.

(Second Embodiment)
Next, a free run control method according to a second embodiment of the present invention will be described. FIG. 8A shows a shift map during free run according to the second embodiment in FIG. 8A, and FIG. 8B shows a graph of the target gear ratio according to the vehicle speed during free run according to the second embodiment. It is a figure which shows the lower limit of the input shaft rotational speed, the lower limit of the 1st output shaft rotational speed, the target 1st output shaft rotational speed, and the 2nd output shaft rotational speed according to vehicle speed to c).

As shown in FIG. 8, in the second embodiment, unlike the first embodiment, the target slip amount by the slip control is changed according to the vehicle speed V of the vehicle Ve. That is, the linear solenoid valve SL2 regulates the second clutch pressure P _C2 so that the rotation speeds of the primary pulley 51 and the secondary pulley 52 maintain the rotation speed at which the shift control can be performed, and the slip rotation speed of the second clutch C2. To control.

  Specifically, FIG. 8A is a shift map similar to that of the first embodiment. Further, as shown in FIG. 8B, the target speed ratio γtgt during the free run is determined based on the coast line in the same manner as in the first embodiment.

In FIG. 8C, the target input shaft is based on the rotational speed Ninlmt of the primary pulley 51 and the rotational speed Noutlmt of the secondary pulley 52, which is the minimum required for speed change control during free run. The rotation number Nintgt indicates a state determined by MAX selection according to the following equation (1).
Nintgt = max (Ninlmt, Noutlmt × γtgt) (1)

Further, the target first output shaft speed Nout1tgt on the upstream side of the second clutch C2 at this time is determined by the following equation (2).
Nout1tgt = Nintgt / γtgt (2)

The MAX selection according to the equation (1) is switched at a point where the target gear ratio γtgt crosses the gear ratio γlmt defined by the following equation (3).
γlmt = Ninlmt / Noutlmt (3)

  As in the first embodiment, the target slip rotation speed in the slip control of the second clutch C2 is the difference between the second output shaft rotation speed Nout2 and the first output shaft rotation speed Nout1tgt (Nout2-Nout1tgt). . Other configurations are the same as those of the first embodiment.

  In the second embodiment described above, the same effect as that of the first embodiment can be obtained, and the target first output shaft rotation speed Nout1tgt is changed according to the vehicle speed, so that the primary pulley of the CVT 5 can be obtained. By maintaining the rotational speeds of 51 and the secondary pulley 52 at the speeds at which the shift control is possible, the engine speed Ne is secured while ensuring the shift control performance during the slip control of the second clutch C2 during the free run. Can be made as low as possible, so that the free-run execution distance can be increased.

(Third embodiment)
Next, a free run control method according to a third embodiment of the present invention will be described. FIG. 9 is a flowchart for explaining the free-run control method according to the third embodiment.

As shown in FIG. 9, in the third embodiment, steps ST31 to ST43 and steps ST46 to ST52 are the same as steps ST1 to ST13 and steps ST14 to ST20 in the first embodiment, respectively. In step ST43, as in step ST13, when the determination unit 104 determines that the vehicle speed V is less than the total speed (V _C2 + V _hys ) of the predetermined vehicle speed V _C2 and the hysteresis speed V _hys (step ST43: No). The process proceeds to step ST44 while continuing the slip control.

  Since the slip control is continued in step ST44, unlike the first embodiment, the travel control unit 101 estimates the temperature of the second clutch C2 based on, for example, the following equations (4) to (6). To do. Note that the temperature of the second clutch C2 is the temperature of components such as a friction material and a separator plate that constitute the second clutch C2.

(4) is an equation for estimating the calorific value Q _in. The heat generation amount Qin can be estimated by time-integrating the product of the transmission torque T _slip and the slip rotation speed (Nout2-Nout1) from the slip start time T1 to the second clutch C2 to the time T2 at which the temperature is estimated. .

Expression (5) is an expression for estimating the heat dissipation amount Q _out . The heat radiation amount can be estimated by a function f having the lubricating flow rate Qlub, the first output shaft rotational speed Nout1, and the second output shaft rotational speed Nout2 as variables.

Expression (6) is an expression for calculating the estimated temperature T _C2 of the second clutch C2. The estimated temperature T _C2 has the heat generation amount Q _in obtained by the equation (4), the heat release amount Q _out obtained by the equation (5), and the heat capacity C _out of the components constituting the second clutch C2 as variables. It can be calculated by the function g. Thereafter, the process proceeds to step ST45.

In step ST45, the determination unit 104 determines whether or not the estimated temperature T _C2 of the second clutch C2 is higher than a predetermined temperature T _C2lmt . When the determination unit 104 determines that the estimated temperature T _C2 of the second clutch C2 is higher than the predetermined temperature T _C2lmt (step ST45: Yes), the process proceeds to step ST47. In step ST47, the engine 1 is restarted in the same manner as in step ST15 regardless of whether or not there is a free-run return instruction from the driver.

On the other hand, when the determination unit 104 determines that the estimated temperature T _C2 of the second clutch C2 is _{equal to} or lower than the predetermined temperature T _C2lmt (step ST45: No), the process proceeds to step ST46. In step ST46, whether or not the free-run return condition is satisfied is determined in the same manner as in step ST14. About another structure, it is the same as that of 1st Embodiment.

  In the third embodiment, the same effect as that of the first embodiment can be obtained, and the second clutch can be determined from the amount of heat generated and the amount of heat released from the second clutch C2 during the slip control for the second clutch C2. By estimating the temperature of the C2 component and constantly monitoring it, if the temperature of the component of the second clutch C2 exceeds a predetermined temperature, there is no instruction from the driver to return to free run. Since it is possible to forcibly return from the free run, the durability of the second clutch C2 can be ensured.

  As mentioned above, although embodiment of this invention was described concretely, this invention is not limited to the above-mentioned embodiment, Various deformation | transformation based on the technical idea of this invention is possible. For example, the numerical values given in the above-described embodiment are merely examples, and different numerical values may be used as necessary.

  For example, in the above-described embodiment, the second clutch C2 is released and the free run is performed. However, the first clutch C1 may be released and the free run may be performed. In this case, the slip control during the free run is executed for the first clutch C1 instead of the second clutch C2 described above.

DESCRIPTION OF SYMBOLS 1 Engine 2 Torque converter 3 Input shaft 5 Continuously variable transmission 6 Gear train 7 Output shaft 10 Drive shaft 11 Drive wheel 31 Vehicle speed sensor 100 ECU
101 Travel Control Unit 102 Return Control Unit 103 Gear Ratio Setting Unit 104 Determination Unit 200 Hydraulic Control Device C1 First Clutch C2 Second Clutch S1 Dog Clutch

Claims (1)

In a vehicle control device for controlling a vehicle including an engine, a continuously variable transmission, and a clutch provided between the continuously variable transmission and a drive wheel in a power transmission path,
Gear ratio setting means for setting a target gear ratio according to the vehicle speed of the vehicle in the continuously variable transmission;
When a predetermined execution condition is satisfied and the vehicle speed is equal to or higher than a predetermined speed while the vehicle is running, the vehicle is coasted with the clutch being released and the supply of fuel into the engine stopped. When the predetermined execution condition is satisfied and the vehicle speed is less than the predetermined speed while the vehicle is running, the continuously variable speed change is performed by setting the clutch to a slip state and stopping the fuel supply into the engine. A vehicle control apparatus, comprising: a travel speed control unit that changes a speed ratio of the vehicle from a speed ratio detected in advance to a target speed ratio set by the speed ratio setting unit.

Images