JP2012225465A - Vehicle control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle control device that can suppress unnecessary supply of a working fluid and improve fuel consumption.SOLUTION: The control device includes: an engine stop determination unit 66 which connects a transmission 14 to an engine 11 mounted on a vehicle via a torque converter and a power transmission clutch 13, connects a driving wheel to the transmission 14 via a deceleration and differential mechanism and determines whether the engine stop permission conditions are established; an engine control unit (automatic stopping means) 67 which can automatically stop the engine 11 when the engine stop permission conditions are established; and a transmission control unit 69 which adjusts the control oil pressure of the transmission 14 in accordance with the vehicle speed, when the engine 11 is automatically stopped by the engine control unit 67.

Description

  The present invention relates to a vehicle control device.

  Various belt-type continuously variable transmissions (CVTs) have been proposed as power transmission devices for vehicles. This continuously variable transmission has a primary pulley provided on the drive side, a secondary pulley provided on the output side, and a drive belt that is wound around the primary pulley and the secondary pulley. And the output rotation speed can be adjusted steplessly by changing the ratio (pulley ratio) of the winding diameter of the drive belt to each pulley by hydraulic pressure.

  An example of such a continuously variable transmission is described in Patent Document 1 below. In the control device for a continuously variable transmission described in Patent Document 1, when the rotation speed of the primary pulley is equal to or lower than a predetermined value, the vehicle speed is equal to or lower than the predetermined value, and the deceleration of the vehicle is larger than the predetermined value. In addition, the secondary pressure is set to a high pressure, the shift speed at which the drive belt generates slippage with respect to the primary pulley is set to a high speed, sudden deceleration is performed, an extremely low vehicle speed state is achieved, and the rotation speed of the primary pulley decreases rapidly. Even so, the occurrence of gloss slip of the drive belt is prevented.

JP 2002-310276 A

  In the above-described conventional continuously variable transmission control device, when the vehicle is brought into an extremely low vehicle speed state due to sudden deceleration of the vehicle and the primary pulley rotation speed suddenly decreases, the secondary belt is increased more than usual so that the drive belt is moved to the primary belt. The shift speed at which the pulley slips is increased to prevent the occurrence of gloss slip of the drive belt. However, if the secondary pressure is suddenly increased when the primary pulley rotation speed suddenly drops, a large load is applied to the oil pump, accumulator, etc., as a lubrication system, and the loss in oil supply becomes larger than necessary, resulting in fuel efficiency. There is a problem that gets worse.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vehicle control device capable of improving fuel efficiency by suppressing wasteful supply of working fluid.

  A vehicle control device according to the present invention includes a drive source mounted on a vehicle, a belt-type continuously variable transmission that changes the rotational speed of the drive source in accordance with a control hydraulic pressure and transmits a drive force to wheels, An automatic stop means capable of automatically stopping the drive source in accordance with an operating state, and a control for adjusting a control hydraulic pressure of the belt-type continuously variable transmission in accordance with a vehicle speed when the drive source is automatically stopped by the automatic stop means. And a hydraulic pressure adjusting means.

  In the vehicle control apparatus, it is preferable that the control hydraulic pressure adjusting means adjusts the control hydraulic pressure to be lower as the vehicle speed is lower.

  In the vehicle control device, the control hydraulic pressure adjusting means is configured to control the belt-type continuously variable transmission according to the vehicle speed if the vehicle speed is lower than a predetermined low vehicle speed when the drive source is automatically stopped. It is preferable to adjust the control oil pressure.

  The vehicle control device according to the present invention adjusts the control hydraulic pressure of the belt-type continuously variable transmission according to the vehicle speed when the drive source automatically stops, so that it is possible to improve fuel efficiency by suppressing wasteful supply of working fluid. There is an effect that.

FIG. 1 is a schematic configuration diagram illustrating a vehicle control device according to the first embodiment of the present invention. FIG. 2 is a control block diagram illustrating the vehicle control apparatus according to the first embodiment. FIG. 3 is a flowchart showing a flow of processing of engine stop control by the vehicle control device of the first embodiment. FIG. 4 is a graph showing the required hydraulic pressure of the transmission with respect to the vehicle speed. FIG. 5 is a flowchart showing a process flow of engine stop control by the vehicle control device according to the second embodiment of the present invention. FIG. 6 is a graph showing the required hydraulic pressure of the transmission with respect to the vehicle speed.

  Hereinafter, an embodiment of a vehicle control device according to the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by this embodiment, and when there are a plurality of embodiments, it includes those configured by combining the embodiments.

Embodiment 1
1 is a schematic configuration diagram illustrating a vehicle control device according to a first embodiment of the present invention, FIG. 2 is a control block diagram illustrating the vehicle control device of the first embodiment, and FIG. 3 is a vehicle control device according to the first embodiment. FIG. 4 is a flowchart showing the processing flow of engine stop control, and FIG. 4 is a graph showing the required hydraulic pressure of the transmission with respect to the vehicle speed.

  In the vehicle control apparatus of the first embodiment, as shown in FIG. 1, the vehicle 10 includes an engine 11, a torque converter 12, a power transmission clutch 13, a transmission 14, a speed reduction / differential mechanism 15, and driving wheels. 16 is installed. Here, the engine 11 functions as a drive source of the present invention.

  The engine 11 is a power source of the vehicle 10, and can convert the combustion energy of the fuel into the rotational motion of the crankshaft (output shaft) 21 and output it. The torque converter 12 is a fluid transmission device that transmits power via oil (working fluid), and includes a pump impeller 31 and a turbine runner 32. The pump impeller 31 is connected to the crankshaft 21 of the engine 11, and the turbine runner 32 is connected to the power transmission clutch 13 by a connecting shaft 33. Therefore, the rotation input from the engine 11 to the pump impeller 31 is transmitted to the turbine runner 32 via the working fluid and input to the power transmission clutch 13 via the connecting shaft 33.

  The power transmission clutch 13 is a friction engagement type clutch device, and the power transmission between the engine 11 and the transmission 14 can be interrupted by opening the power transmission clutch 13. The power transmission clutch 13 has an input side engaging member 41 and an output side engaging member 42. The input side engaging member 41 is connected to the turbine runner 32 by a connecting shaft 33, and the output side engaging member 42 is connected to the transmission 14. In the power transmission clutch 13, the input side engaging member 41 and the output side engaging member 42 can be moved toward and away from each other by an actuator operated by hydraulic pressure or electromagnetic force. Therefore, the power transmission clutch 13 can be switched between the fully engaged state, the semi-engaged state, and the released state according to the clutch pressure (clutch engagement pressure) applied by the actuator. The actuator can control the degree of engagement of the power transmission clutch 13 in the half-engaged state, that is, the slip amount and the slip rate.

  The transmission 14 is a belt-type continuously variable transmission, and connects the engine 11 and the drive wheels 16, specifically, the power transmission clutch 13 and the speed reduction / differential mechanism 15. The transmission 14 includes a primary pulley 51, a secondary pulley 52, a belt 53, and a hydraulic control device (not shown). The primary pulley 51 includes a primary fixed sheave 51a, a primary movable sheave 51b, and a primary shaft 51c. The secondary pulley 52 has a secondary fixed sheave 52a, a secondary movable sheave 52b, and a secondary shaft 52c. Then, a substantially V-shaped primary groove formed between the primary fixed sheave 51a and the primary movable sheave 51b, and a substantially V-shaped secondary groove formed between the secondary fixed sheave 52a and the secondary movable sheave 52b. Between the two, an endless belt 53 is wound around. In the transmission 14, power is transmitted from the primary pulley 51 to the secondary pulley 52 via the belt 53.

  The hydraulic control device can control the transmission ratio of the transmission 14 by controlling the hydraulic pressure (control hydraulic pressure) supplied to the primary pulley 51 and the secondary pulley 52. Here, the gear ratio is a value obtained by dividing the rotational speed of the primary shaft 51c, which is the input shaft, by the rotational speed of the secondary shaft 52c, which is the output shaft. That is, the gear ratio corresponds to the rotation speed ratio between the primary shaft 51c and the secondary shaft 52c. Therefore, the hydraulic control device can change the gear ratio steplessly by adjusting the supply hydraulic pressure and changing the groove width of the primary groove and the groove width of the secondary groove.

  The speed reduction / differential mechanism 15 connects the secondary shaft 52c and the drive wheel 16 in the transmission 14, and has a speed reduction mechanism and a differential mechanism by a combination of gears. Accordingly, the rotation input from the transmission 14 is decelerated by the deceleration / differential mechanism 15 and distributed to the left and right drive wheels 16.

  As shown in FIG. 2, the vehicle 10 is equipped with an electronic control unit (ECU) 61, which can control the engine 11, the power transmission clutch 13, and the transmission 14. The ECU 61 can control the fuel injection amount by the injector, the fuel injection timing, the ignition timing by the spark plug, and the like based on the operating state of the engine 11 by the driver and the operating state of the engine 11.

  Further, the ECU 61 can execute deceleration eco-run control and free-run control (hereinafter, eco-run control) by controlling the vehicle 10. In this eco-run control, the power transmission clutch 13 is released to cut off power transmission between the engine 11 and the transmission 14, and then the vehicle 10 is coasted with the engine 11 stopped. This eco-run control can improve fuel consumption by stopping fuel consumption in the engine 11.

  That is, the ECU 61 opens the power transmission clutch 13 and automatically stops the engine 11 when an automatic engine stop condition (for example, the accelerator pedal by the driver is not depressed for a predetermined time) is satisfied while the vehicle 10 is traveling. . Further, the ECU 61 automatically connects the power transmission clutch 13 and automatically starts the engine 11 when an engine automatic start condition (for example, depression of an accelerator pedal by a driver) is satisfied while the vehicle 10 is stopped. To do. When the ECU 61 automatically stops the engine 11, fuel supply to the engine 11 and ignition are stopped.

  More specifically, the ECU 61 is connected to a brake sensor 62, an accelerator operation amount sensor 63, a vehicle speed sensor 64, and a gradient sensor 65. The brake sensor 62 can detect the operation amount with respect to the brake pedal and the presence or absence of the brake operation. The operation amount with respect to the brake pedal is, for example, a pedal stroke of the brake pedal or a pedaling force input to the brake pedal. The presence or absence of a brake operation is detected by, for example, a switch. The accelerator operation amount sensor 63 can detect an operation amount with respect to the accelerator pedal, for example, an accelerator opening. The vehicle speed sensor 64 can detect the traveling speed of the vehicle 10 and detects the vehicle speed based on the rotational speed of each wheel.

  The gradient sensor 65 can detect the gradient of the road surface on which the vehicle 10 is traveling. The gradient sensor 65 detects or estimates the gradient of the surface of the road on which the vehicle 10 travels based on, for example, the tilt of the vehicle 10 in the front-rear direction. The ECU 61 receives signals indicating the detection results of the sensors 62, 63, 64, and 65.

  The ECU 61 has an engine stop determination unit 66. The engine stop determination unit 66 determines whether to stop the engine 11 based on the detection results of the brake sensor 62, the accelerator operation amount sensor 63, the vehicle speed sensor 64, and the gradient sensor 65. That is, the engine stop determination unit 66 is, for example, a condition that the brake pedal is depressed, a condition that the accelerator opening is 0, a condition that the vehicle speed is traveling below a predetermined vehicle speed, and a road gradient is within a predetermined range. It has an engine stop permission condition including conditions, and if all these conditions are satisfied, it is determined that the engine 11 is stopped and the eco-run control is executed.

  The ECU 61 includes an engine control unit 67 that controls the engine 11, a clutch control unit 68 that controls the power transmission clutch 13, and a transmission control unit 69 that controls the transmission 14. Here, the engine control unit 67 functions as an automatic stop unit according to the present invention, and the transmission control unit 69 functions as a control hydraulic pressure adjustment unit according to the present invention.

  When the engine stop determining unit 66 determines not to stop the engine 11, the engine control unit 67 determines an engine control amount based on the target torque, and controls the engine 11 based on the determined engine control amount. The engine control amount is, for example, a control amount related to fuel injection control or a control amount related to ignition control. In addition, when the engine stop determination unit 66 determines that the engine 11 is not stopped, the clutch control unit 68 controls the power transmission clutch 13 based on the target clutch oil pressure. Further, the transmission control unit 69 determines a transmission control amount based on the target rotational speed, and controls the transmission 14 based on the determined transmission control amount. The transmission control amount is, for example, a control amount for realizing a gear ratio and a change speed of the gear ratio (shift speed), and is output to the hydraulic control device of the transmission 14.

  Further, when the engine stop determining unit 66 determines to stop the engine 11, the engine control unit 67 controls the engine 11 so that the engine control amount is set to 0 regardless of the target torque, and fuel injection and ignition are stopped. When the engine stop determination unit 66 determines to stop the engine 11, the clutch control unit 68 sets the clutch pressure to 0 regardless of the target clutch oil pressure and releases the power transmission clutch 13 before stopping the engine 11.

  By the way, if the engine stop permission condition is satisfied while the vehicle 10 is traveling, the engine 11 is stopped after the power transmission clutch 13 is released. At this time, an oil pump (not shown) driven by the engine 11 is stopped. This makes it difficult for the transmission 14 to secure the hydraulic pressure that the hydraulic control device supplies to the primary pulley 51 and the secondary pulley 52.

  Therefore, in the first embodiment, when the engine stop determination unit 66 determines to stop the engine 11, the clutch control unit 68 releases the power transmission clutch 13, and the engine control unit 67 automatically stops the engine 11. The transmission control unit 69 adjusts the control hydraulic pressure of the transmission 14 according to the vehicle speed, that is, the hydraulic pressure (control hydraulic pressure) supplied to the primary pulley 51 and the secondary pulley 52 by the hydraulic control device.

  At this time, the transmission control unit 69 adjusts the control hydraulic pressure to be lower as the vehicle speed is lower. Further, when the engine 11 is automatically stopped, the transmission control unit 69 adjusts the control hydraulic pressure of the transmission 14 according to the vehicle speed if the vehicle speed is lower than a predetermined low vehicle speed.

  Hereinafter, engine stop control by the vehicle control apparatus of Embodiment 1 will be described in detail with reference to the flowchart of FIG.

  In the vehicle control apparatus of the first embodiment, as shown in FIG. 3, the engine stop determination unit 66 determines whether the engine stop permission condition is satisfied in the traveling vehicle 10, and the engine stop permission condition is If established, the clutch control unit 68 releases the power transmission clutch 13 (clutch pressure is 0), and the engine control unit 67 stops the engine 11.

  In step S <b> 11, the ECU 61 determines whether the engine 11 is automatically stopped while the vehicle 10 is traveling. Here, if it is determined that the engine 11 is not automatically stopped while the vehicle 10 is traveling, the routine exits without doing anything. On the other hand, if it is determined that the engine 11 is automatically stopped while the vehicle 10 is traveling, it is determined in step S12 whether the vehicle speed is lower than a predetermined low vehicle speed V1 (for example, 10 km / h). . Here, if it is determined that the vehicle speed is equal to or higher than the predetermined low vehicle speed V1, the routine is terminated without doing anything.

  On the other hand, if it is determined that the vehicle speed is lower than the predetermined low vehicle speed V1, the transmission control unit 69 calculates the required hydraulic pressure of the transmission 14 with respect to the vehicle speed in step S13. In this case, the required hydraulic pressure of the transmission 14 may be obtained from the graph showing the required hydraulic pressure of the transmission 14 with respect to the vehicle speed shown in FIG. The graph showing the required hydraulic pressure of the transmission 14 with respect to the vehicle speed shown in FIG. 4 is obtained in advance by experiments. In the low vehicle speed region where the vehicle speed is lower than the low vehicle speed V1, the need for the transmission 14 with respect to the increase in the vehicle speed. The hydraulic pressure tends to increase proportionally, and in the region where the vehicle speed is V1 or higher, the required hydraulic pressure of the transmission 14 tends to be constant as the vehicle speed increases. That is, the predetermined low vehicle speed V1 is the maximum vehicle speed in a region where the required hydraulic pressure of the transmission 14 increases in proportion to the increase in the vehicle speed. In addition, since the required hydraulic pressure of the transmission 14 differs according to various driving states with respect to the increase in vehicle speed, it is desirable to prepare a plurality of graphs according to each driving state.

  When the required hydraulic pressure of the transmission 14 with respect to the vehicle speed is calculated, the transmission control unit 69 outputs the required hydraulic pressure, that is, the transmission control amount to the transmission 14 in step S14. In the transmission 14, the hydraulic control device sets the transmission ratio by supplying the control oil pressure corresponding to the required oil pressure (transmission control amount) to the primary pulley 51 and the secondary pulley 52. Note that the control in which the transmission control unit 69 sets the control hydraulic pressure of the transmission 14 with respect to the vehicle speed is canceled when the engine 11 is started.

  As described above, in the vehicle control apparatus of the first embodiment, the transmission 14 is connected to the engine 11 mounted on the vehicle 10 via the torque converter 12 and the power transmission clutch 13, and the speed reduction / difference is connected to the transmission 14. An engine stop determination unit 66 that determines whether or not an engine stop permission condition is satisfied by connecting the drive wheels 16 via the moving mechanism 15 and an engine control that can automatically stop the engine 11 when the engine stop permission condition is satisfied. And a transmission control unit 69 that adjusts the control hydraulic pressure of the transmission 14 in accordance with the vehicle speed when the engine 11 is automatically stopped by the engine control unit 67.

  Therefore, in the transmission 14, the required control oil pressure changes linearly according to the vehicle speed. Therefore, when the engine 11 is automatically stopped, the control oil pressure of the transmission 14 is adjusted according to the vehicle speed, thereby changing the speed. The machine 14 ensures only an appropriate control oil pressure according to the vehicle speed, and can suppress wasteful supply of oil (working fluid) by a lubrication system such as an oil pump and an accumulator, thereby improving fuel efficiency. can do.

  In the vehicle control apparatus of the first embodiment, the transmission control unit 69 adjusts the control hydraulic pressure to be lower as the vehicle speed is lower. Therefore, the transmission control unit 69 can supply the minimum control hydraulic pressure to the transmission 14 according to the vehicle speed, and can improve fuel efficiency.

  In the vehicle control device of the first embodiment, when the engine 11 is automatically stopped and the vehicle speed is lower than the predetermined low vehicle speed V1 when the engine 11 is automatically stopped, the transmission control unit 69 sets the transmission 14 according to the vehicle speed. The control hydraulic pressure is adjusted. Therefore, the control hydraulic pressure of the transmission 14 is adjusted according to the vehicle speed only in the low vehicle speed region where the control hydraulic pressure required according to the vehicle speed changes linearly, and the control hydraulic pressure of the transmission 14 is set appropriately. Can do.

[Embodiment 2]
FIG. 5 is a flowchart showing the flow of processing of engine stop control by the vehicle control apparatus according to Embodiment 2 of the present invention, and FIG. 6 is a graph showing the required hydraulic pressure of the transmission with respect to the vehicle speed. The basic configuration of the vehicle control device of the present embodiment is substantially the same as that of the above-described first embodiment, and will be described with reference to FIGS. 1 and 2 and have the same functions as those of the above-described embodiment. The members having the same reference numerals are given the detailed descriptions thereof.

  In the vehicle control apparatus of the second embodiment, as shown in FIGS. 1 and 2, the vehicle 10 includes an engine 11, a torque converter 12, a power transmission clutch 13, a transmission 14, a speed reduction / differential mechanism 15, and the like. The drive wheel 16 is mounted. The vehicle 10 is equipped with an electronic control unit (ECU) 61, which can control the engine 11, the power transmission clutch 13, and the transmission 14.

  That is, the ECU 61 is connected to a brake sensor 62, an accelerator operation amount sensor 63, a vehicle speed sensor 64, and a gradient sensor 65. The ECU 61 has an engine stop determination unit 66. The engine stop determination unit 66 determines whether to stop the engine 11 based on the detection results of the brake sensor 62, the accelerator operation amount sensor 63, the vehicle speed sensor 64, and the gradient sensor 65. That is, when the engine stop permission condition is satisfied, the engine stop determination unit 66 determines to stop the engine 11 and execute the eco-run control.

  The ECU 61 has an engine control unit 67, a clutch control unit 68, and a transmission control unit 69. When the engine stop determining unit 66 determines to stop the engine 11, the engine control unit 67 sets the engine control amount to 0 regardless of the target torque, and controls the engine 11 to stop fuel injection and ignition. When the engine stop determination unit 66 determines to stop the engine 11, the clutch control unit 68 sets the clutch pressure to 0 regardless of the target clutch oil pressure and releases the power transmission clutch 13 before stopping the engine 11.

  In the second embodiment, when the engine stop determination unit 66 determines to stop the engine 11, the clutch control unit 68 releases the power transmission clutch 13, and the engine control unit 67 automatically stops the engine 11. The transmission control unit 69 adjusts the control hydraulic pressure of the transmission 14 according to the vehicle speed, that is, the hydraulic pressure (control hydraulic pressure) supplied to the primary pulley 51 and the secondary pulley 52 by the hydraulic control device.

  Here, the transmission control unit 69 adjusts the control hydraulic pressure of the transmission 14 in accordance with not only the vehicle speed but also the road surface condition on which the vehicle 10 travels, that is, the road surface friction coefficient μ.

  Hereinafter, engine stop control by the vehicle control apparatus of Embodiment 2 will be described in detail with reference to the flowchart of FIG.

  In the vehicle control apparatus of the second embodiment, as shown in FIG. 5, in step S21, the ECU 61 determines the road surface condition on which the vehicle 10 travels. In this case, for example, the road surface friction coefficient μ may be calculated based on the vehicle weight, the braking force or driving force of each driving wheel.

  The engine stop determination unit 66 determines whether or not the engine stop permission condition is satisfied in the traveling vehicle 10, and when the engine stop permission condition is satisfied, the clutch control unit 68 opens the power transmission clutch 13 ( The clutch control is set to 0), and the engine control unit 67 stops the engine 11.

  In step S22, the ECU 61 determines whether or not the engine 11 is automatically stopped while the vehicle 10 is traveling. Here, if it is determined that the engine 11 is not automatically stopped while the vehicle 10 is traveling, the routine exits without doing anything. On the other hand, if it is determined that the engine 11 is automatically stopped while the vehicle 10 is traveling, it is determined in step S23 whether the vehicle speed is lower than a predetermined low vehicle speed V1 (for example, 10 km / h). . Here, if it is determined that the vehicle speed is equal to or higher than the predetermined low vehicle speed V1, the routine is terminated without doing anything. The predetermined low vehicle speed V1 may be adjusted according to the road surface condition (road surface friction coefficient μ).

  On the other hand, if it is determined that the vehicle speed is lower than the predetermined low vehicle speed V1, the transmission control unit 69 calculates the required hydraulic pressure of the transmission 14 with respect to the vehicle speed in step S24. In this case, the required hydraulic pressure of the transmission 14 may be obtained from the graph showing the required hydraulic pressure of the transmission 14 with respect to the vehicle speed shown in FIG. The graph representing the required hydraulic pressure of the transmission 14 with respect to the vehicle speed shown in FIG. 6 is obtained in advance by experiments. In the low vehicle speed region where the vehicle speed is lower than the low vehicle speed V1, the need for the transmission 14 with respect to the increase in the vehicle speed. The hydraulic pressure tends to increase proportionally, and in the region where the vehicle speed is V1 or higher, the required hydraulic pressure of the transmission 14 tends to be constant as the vehicle speed increases. That is, the predetermined low vehicle speed V1 is the maximum vehicle speed in a region where the required hydraulic pressure of the transmission 14 increases in proportion to the increase in the vehicle speed.

  Further, since the required hydraulic pressure of the transmission 14 varies depending on the road surface friction coefficient μ with respect to the increase in the vehicle speed, in the present embodiment, the DRY road surface (dry road surface) and the low μ road surface (wet road surface) are used. Two corresponding curves are set. That is, as the road surface friction coefficient μ is smaller, the required hydraulic pressure of the transmission 14 is larger. In this case, the low vehicle speed V1 is also different according to the road surface friction coefficient μ. The three curves shown in FIG. 6 are also obtained in advance by experiments.

  When the required hydraulic pressure of the transmission 14 with respect to the vehicle speed is calculated, the transmission control unit 69 outputs the required hydraulic pressure, that is, the transmission control amount, to the transmission 14 in step S25. In the transmission 14, the hydraulic control device sets the transmission ratio by supplying the control oil pressure corresponding to the required oil pressure (transmission control amount) to the primary pulley 51 and the secondary pulley 52. Note that the control in which the transmission control unit 69 sets the control hydraulic pressure of the transmission 14 with respect to the vehicle speed is canceled when the engine 11 is started.

  Thus, in the vehicle control apparatus of the second embodiment, when the engine stop determination unit 66 determines to stop the engine 11, the clutch control unit 68 opens the power transmission clutch 13, and the engine control unit 67 After the automatic stop, the transmission control unit 69 controls the control hydraulic pressure of the transmission 14 according to the vehicle speed and the road surface friction coefficient μ, that is, the hydraulic pressure (control hydraulic pressure) supplied to the primary pulley 51 and the secondary pulley 52 by the hydraulic control device. Adjust.

  Therefore, in the transmission 14, the required control hydraulic pressure changes linearly according to the vehicle speed, and the required control hydraulic pressure increases / decreases according to the road surface friction coefficient. Therefore, when the engine 11 automatically stops, By adjusting the control hydraulic pressure of the transmission 14 according to the road surface friction coefficient, the transmission 14 ensures only an appropriate control hydraulic pressure according to the vehicle speed, and the oil (by an oil pump, an accumulator, etc.) Wasteful supply of the working fluid) can be suppressed, and as a result, fuel consumption can be improved.

11 Engine (drive source)
12 Torque converter 13 Power transmission clutch 14 Transmission 15 Deceleration / differential mechanism 16 Drive wheel 61 Electronic control unit, ECU
62 Brake sensor 63 Accelerator operation amount sensor 64 Vehicle speed sensor 65 Gradient sensor 66 Engine stop determination unit 67 Engine control unit (automatic stop means)
68 Clutch control section 69 Transmission control section (control hydraulic pressure adjusting means)

Claims (3)

A drive source mounted on the vehicle;
A belt-type continuously variable transmission that shifts the rotational speed of the drive source in accordance with the control oil pressure and transmits the driving force to the wheels;
Automatic stop means capable of automatically stopping the drive source according to the driving state of the vehicle;
Control oil pressure adjusting means for adjusting the control oil pressure of the belt type continuously variable transmission according to the vehicle speed when the drive source is automatically stopped by the automatic stop means;
A vehicle control device comprising:   The vehicle control apparatus according to claim 1, wherein the control hydraulic pressure adjusting means adjusts the control hydraulic pressure to be lower as the vehicle speed is lower.   The control hydraulic pressure adjusting means adjusts the control hydraulic pressure of the belt type continuously variable transmission according to the vehicle speed if the vehicle speed is lower than a predetermined low vehicle speed when the drive source is automatically stopped. The vehicle control device according to claim 1 or 2, characterized in that

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