Vehicle control device

Abstract

To appropriately execute gear ratio control of a belt-type continuously variable transmission even when a vehicle mounted with the belt-type continuously variable transmission travels while performing a garage shift operation.SOLUTION: In a vehicle control device which performs belt-clamping force control and gear ratio control of a belt-type continuously variable transmission 3 through hydraulic control using hydraulic pressure generated by an oil pump driven by an engine, when a driver performs a garage shift, which is a shift operation that switches a shift range of the bet-type continuously variable transmission between a travel range (D range or R range) and a non-travel range (N range) while a vehicle is traveling at a predetermined low speed, idle-up control is executed (Step S3) to temporarily increase an engine idling speed above a normal idling speed during a non-garage-shift operation.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a control device for a vehicle equipped with a continuously variable transmission, and more particularly to a control device for a vehicle that hydraulically controls the operation of a belt-type continuously variable transmission (belt clamping pressure control and gear ratio control). [Background technology]

[0002] Patent Document 1 describes a control device for a belt-type continuously variable transmission that aims to maintain a maximum gear ratio while suppressing belt slippage. The belt-type continuously variable transmission described in Patent Document 1 includes a primary pulley and a secondary pulley around which a transmission belt is wound, an oil pump, and a hydraulic control device. The oil pump is driven by the output torque of the engine to discharge hydraulic oil. The hydraulic control device applies the hydraulic oil discharged from the oil pump to a primary moving sheave of the primary pulley and a secondary moving sheave of the secondary pulley. The belt-type continuously variable transmission control device controls a primary thrust for moving the primary moving sheave and a secondary thrust for moving the secondary moving sheave. When the maximum gear ratio is required, the belt-type continuously variable transmission control device described in Patent Document 1 reduces the primary target pressure when the secondary target pressure is smaller than the discharge capacity of the oil pump compared to when the secondary target pressure is greater than the discharge capacity of the oil pump. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-60259 Summary of the Invention [Problem to be solved by the invention]

[0004] As described in the above-mentioned Patent Document 1, a belt-type continuously variable transmission has two pulleys, i.e., a primary pulley and a secondary pulley, around which a transmission belt is wound. The belt-type continuously variable transmission performs belt clamping pressure control and speed ratio control by controlling the thrust (or sheave pressure) for moving the movable sheaves of the primary pulley and secondary pulley in the direction of their rotation axes. For example, belt clamping pressure control for preventing belt slippage is performed by hydraulically controlling the sheave pressure of the secondary pulley. Meanwhile, speed ratio control for changing the transmission belt's winding diameter and changing the speed ratio is performed by hydraulically controlling the sheave pressure of the primary pulley.

[0005] Typically, the speed ratio control of a belt-type continuously variable transmission is performed by feedback control or a combination of feedback control and feedforward control. For example, in order to make the actual speed ratio (actual speed ratio) of the belt-type continuously variable transmission follow the target speed ratio, an upshift amount or a downshift amount is calculated by feedback control. Then, the speed ratio control is performed by hydraulically controlling the sheave pressure of the primary pulley based on the calculated upshift amount or downshift amount. However, when the vehicle is traveling at extremely low speeds, the rotation speeds of the input shaft and output shaft of the belt-type continuously variable transmission cannot be properly detected, and an accurate speed ratio cannot be calculated. Therefore, the speed ratio control is performed using only feedforward control without using feedback control.

[0006] In the speed ratio control using feedforward control described above, the sheave pressure of the secondary pulley (secondary sheave pressure) for preventing belt slippage and the sheave pressure of the primary pulley (primary sheave pressure) for achieving a speed ratio that follows the target speed ratio are commanded to maintain a balance with each other. That is, the command pressure (target value) of the primary sheave pressure and the command pressure (target value) of the secondary sheave pressure are calculated using feedforward control. If the actual secondary sheave pressure (detected value by a hydraulic sensor) is used to calculate the command pressure of the primary sheave pressure, hydraulic vibrations (pulsations) may cause hunting in the speed ratio control. For this reason, the command pressure of the primary sheave pressure is calculated using the command pressure of the secondary sheave pressure using feedforward control. However, for example, when the oil temperature of a belt-type continuously variable transmission is high, the discharge performance of the oil pump that generates each sheave pressure is reduced, and the balance between the primary sheave pressure and the secondary sheave pressure (actual pressure) is lost toward the upshift side. In this case, since the actual speed ratio cannot be made to follow the target speed ratio by feedback control, it is not possible to immediately correct the state in which the actual speed ratio deviates from the target speed ratio.

[0007] Furthermore, in situations where a so-called garage shift is performed, in which the driver repeatedly switches between shift ranges (D, R, N) while the vehicle is traveling at a low speed, such as when parking the vehicle in a garage or when making a turn or maneuver in a narrow space, gear ratio control is performed by controlling the hydraulic pressure of the fail-safe valve. For example, if a failure occurs while the vehicle is traveling, such as when the solenoid valve of the belt-type continuously variable transmission stops operating, the fail-safe valve sets a large gear ratio or the maximum gear ratio, enabling the vehicle to escape. However, when the gear ratio control of the belt-type continuously variable transmission is performed using the fail-safe valve in such a situation where a garage shift is performed, the primary sheave pressure cannot be controlled in the same way as in normal gear ratio control, so the command pressure of the primary sheave pressure is mechanically set. In this case, the command pressure of the primary sheave pressure is set higher than normal in consideration of a safety factor. Therefore, the gear ratio of the belt-type continuously variable transmission is set to the upshift side compared to normal gear ratio control.

[0008] As described above, when a vehicle equipped with a belt-type continuously variable transmission travels at low vehicle speeds and performs a so-called garage shift, a state in which the gear ratio control is performed by the feedforward control described above and a state in which the gear ratio control is performed using the fail-safe valve described above alternately repeat. As a result, a state in which a gear ratio on the upshift side that is smaller than the target gear ratio (i.e., the maximum gear ratio) continues to be set. Therefore, the belt-type continuously variable transmission continues to gradually upshift, which may result in a shortage of driving force for the vehicle.

[0009] This invention was devised with an eye on the above-mentioned technical problems, and aims to provide a vehicle control device that can appropriately perform gear ratio control of a belt-type continuously variable transmission even when a vehicle equipped with the belt-type continuously variable transmission is traveling at low vehicle speeds using garage shifting. [Means for solving the problem]

[0010] In order to achieve the above object, the present invention provides a vehicle control device comprising an engine, a belt-type continuously variable transmission having a primary pulley and a secondary pulley around which a transmission belt is wound, and which transmits engine torque output by the engine to drive wheels, and an oil pump driven by the engine, which hydraulically controls the primary sheave pressure supplied to the primary pulley and the secondary sheave pressure supplied to the secondary pulley using oil pressure generated by the oil pump, and performs belt narrowing pressure control and gear ratio control of the belt-type continuously variable transmission, and which includes a control unit that controls the belt-type continuously variable transmission, and which is characterized in that when a garage shift is performed by a driver's shift operation while driving, switching the shift range of the belt-type continuously variable transmission between a driving range (i.e., D range and R range) in which the engine torque is transmitted to the drive wheels and a non-driving range (i.e., N range) in which the engine torque is not transmitted to the drive wheels, the control unit performs idle-up control to temporarily increase the idling speed of the engine above the idling speed that is set during normal times when the garage shift is not being performed.

[0011] In addition, the control unit in the present invention may be configured to execute the idle-up control when the garage shift is performed and the temperature of the oil discharged by the oil pump is equal to or higher than a predetermined oil temperature threshold at which the discharge performance of the oil pump decreases.

[0012] Furthermore, the control unit in the present invention may be configured to terminate the idle-up control when the vehicle speed becomes higher than a predetermined vehicle speed threshold while the idle-up control is being executed and the actual gear ratio of the belt-type continuously variable transmission follows the target gear ratio (or maximum gear ratio) of the belt-type continuously variable transmission. [Effects of the Invention]

[0013] The vehicle control device of the present invention controls a vehicle equipped with a belt-type continuously variable transmission and performs belt narrowing pressure control and gear ratio control of the belt-type continuously variable transmission. For example, when the vehicle is traveling at extremely low speeds, such as when parking the vehicle in a garage or turning or maneuvering in a narrow space, the rotation speeds of the input shaft and output shaft of the belt-type continuously variable transmission cannot be accurately detected. In such cases, gear ratio control is performed using only feedforward control without feedback control. In such cases, for example, if the oil in the belt-type continuously variable transmission becomes hot and the oil pump discharge rate decreases, the actual secondary sheave pressure (actual pressure) will be insufficient compared to the commanded secondary sheave pressure, resulting in an imbalance between the primary sheave pressure and the secondary sheave pressure toward the upshift side. Furthermore, when a so-called garage shift is performed, in which the shift range is switched between D, R, and N while the vehicle is traveling, a fail-safe valve is used to set the commanded primary sheave pressure higher than normal to perform gear ratio control. As a result, the gear ratio of the belt-type continuously variable transmission is set to a higher upshift side than normal. Therefore, in the vehicle control device of the present invention, when the above-described garage shift is performed, the engine is temporarily idled at a higher rotational speed than normal (idle-up control is executed). By increasing the engine idling speed, the oil pump discharge volume can be ensured, thereby preventing the above-described imbalance in sheave pressure. Furthermore, by ensuring the oil pump discharge volume and obtaining an appropriate oil pressure, the belt clamping pressure can be controlled as desired. Therefore, even if the belt-type continuously variable transmission operates to the upshift side during the above-described garage shift, it can be immediately returned to the maximum gear ratio or a large gear ratio on the downshift side. Therefore, the gear ratio control of the belt-type continuously variable transmission can be executed appropriately.

[0014] Even when a garage shift is performed as described above, the normal oil pump discharge rate can be ensured when the temperature of the oil discharged from the oil pump is lower than a predetermined oil temperature (oil temperature threshold). However, when the oil temperature exceeds the oil temperature threshold, the oil pump's discharge performance deteriorates, reducing the oil discharge rate. As a result, there is a concern that the commanded secondary sheave pressure and the actual secondary sheave pressure may diverge, as described above. Therefore, the vehicle control device of the present invention executes engine idle-up control when a garage shift is performed and the oil temperature exceeds the oil temperature threshold, reducing the oil discharge rate from the oil pump. Therefore, the temporary increase in idling speed as described above can be effectively implemented, allowing for appropriate gear ratio control of the belt-type continuously variable transmission.

[0015] Furthermore, after the execution of the idle-up control is started, when the vehicle speed becomes higher than a preset vehicle speed threshold, it becomes possible to control the speed ratio by feedback control, and as a result, when the actual speed ratio of the belt-type continuously variable transmission is following the target speed ratio (or maximum speed ratio), the execution of the idle-up control is terminated. Therefore, the temporary idle-up control as described above can be executed at an appropriate period, and the speed ratio control of the belt-type continuously variable transmission can be executed appropriately.

[0016] Therefore, according to the vehicle control device of the present invention, even when a vehicle equipped with a belt-type continuously variable transmission performs garage shifting at low vehicle speeds, the gear ratio control of the belt-type continuously variable transmission can be appropriately performed, and an appropriate driving force can be generated to allow the vehicle to run. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a diagram for explaining the configuration of a vehicle equipped with a belt-type continuously variable transmission that is the subject of control in the present invention, and is a diagram that schematically shows the drive system (gear train) and control system. [Figure 2]FIG. 2 is a time chart for explaining the details of the speed ratio control of a belt-type continuously variable transmission according to the prior art and the problems with that speed ratio control. [Figure 3] FIG. 3 is a flowchart for explaining an example of the idle-up control executed by the vehicle control device of the present invention. [Figure 4] FIG. 4 is a time chart for explaining the details of the idle-up control shown in the flowchart of FIG. 3 and the effects of executing the idle-up control. DETAILED DESCRIPTION OF THE INVENTION

[0018] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following embodiments of the present invention will be described with reference to the accompanying drawings. Note that the following embodiments are merely examples of specific embodiments of the present invention and are not intended to limit the scope of the present invention.

[0019] The vehicle to be controlled in the embodiment of the present invention is equipped with a belt-type continuously variable transmission that uses an engine (internal combustion engine) as a driving force source and transmits the engine's output torque (engine torque) to a drive shaft and drive wheels. The vehicle control device in the embodiment of the present invention executes belt clamping pressure control and gear ratio control of the belt-type continuously variable transmission. Figure 1 shows an example of a vehicle and a belt-type continuously variable transmission to be controlled in the embodiment of the present invention.

[0020] 1 includes an engine (ENG) 1 as a driving force source. The vehicle Ve also includes a belt-type continuously variable transmission 3 that transmits torque between the engine 1 and drive wheels 2. The vehicle Ve also includes a detection unit 4 that detects various data used to control the vehicle Ve, and a control unit 5 that controls the operation of the vehicle Ve, particularly the belt-type continuously variable transmission 3.

[0021] The engine 1 is an internal combustion engine, such as a gasoline engine or a diesel engine, that obtains power by burning fuel. The engine 1 is electrically controlled in terms of output adjustment and operating states such as starting and stopping.

[0022] The drive wheels 2 are wheels that generate drive force for the vehicle Ve by transmitting the output torque of the engine 1. In the example shown in FIG. 1, the vehicle Ve is imagined as a front-wheel drive vehicle in which the front wheels are drive wheels 2 and drive force is generated by the front wheels. Note that the vehicle Ve in the embodiment of the present invention may be a front-wheel drive vehicle (not shown) in which the rear wheels are drive wheels 2 and drive force is generated by the rear wheels. Alternatively, the vehicle Ve may be a four-wheel drive vehicle (not shown) in which the output torque of the engine 1 is distributed to the front and rear wheels by a transfer case (not shown), and the front and rear wheels are drive wheels 2. Alternatively, the vehicle may be a four-wheel drive hybrid vehicle (not shown) in which either the front or rear wheels are driven by the engine 1 and the other of the front or rear wheels is driven by a motor.

[0023] The belt-type continuously variable transmission 3 is connected to the output side of the engine 1 via, for example, a torque converter 6, and transmits the output torque of the engine 1 to the drive wheels 2 between the engine 1 and the drive wheels 2. At the same time, it changes the rotation speed of the output shaft 1a of the engine 1. The belt-type continuously variable transmission 3 is a power transmission device that can appropriately and continuously change the ratio of the rotation speed of the output shaft 3b to the rotation speed of the input shaft 3a, i.e., the gear ratio, and the control for changing the gear ratio, i.e., the gear ratio control, is automatically controlled.

[0024] Specifically, the belt-type continuously variable transmission 3 includes, as its main components, a primary pulley 7, a secondary pulley 8, and a power transmission belt 9 that transmits power by being wound around the primary pulley 7 and the secondary pulley 8. The belt-type continuously variable transmission 3 also includes a forward / reverse switching mechanism 10, an oil pump 11, and a hydraulic control device (not shown).

[0025] 1, the primary pulley 7 is provided on the input shaft 3a side and includes a fixed sheave 7a that is fixed to the input shaft 3a and rotates integrally with the input shaft 3a, a movable sheave 7b that rotates integrally with the input shaft 3a and is movable relative to the input shaft 3a in the axial direction (left and right direction in FIG. 1), and a hydraulic cylinder 7c that operates the movable sheave 7b. When performing speed ratio control of the belt-type continuously variable transmission 3, the primary pulley 7 controls the hydraulic pressure (primary sheave pressure) acting on the movable sheave 7b, thereby changing the winding diameter of the power transmission belt 9.

[0026] 1, the secondary pulley 8 is provided on the output shaft 3b side and includes a fixed sheave 8a that is fixed to the output shaft 3b and rotates integrally with the output shaft 3b, a movable sheave 8b that rotates integrally with the output shaft 3b and is movable relative to the output shaft 3b in the axial direction (left and right direction in FIG. 1), and a hydraulic cylinder 8c that operates the movable sheave 8b. When belt clamping pressure control of the belt-type continuously variable transmission 3 is performed, the secondary pulley 8 controls the hydraulic pressure (secondary sheave pressure) acting on the movable sheave 7b, thereby adjusting the belt clamping pressure of the power transmission belt 9.

[0027] In the example shown in FIG. 1 , the forward / reverse switching mechanism 10 is mainly composed of a double-pinion planetary gear mechanism 10a, a forward clutch (C1) 10b, and a reverse brake (B1) 10c. The forward / reverse switching mechanism 10 controls the engagement / disengagement states of the forward clutch 10b and the reverse brake 10c, respectively, to switch the rotation direction of the input shaft 3a between the forward direction and the reverse direction of the vehicle Ve. In addition, the neutral state of the belt-type continuously variable transmission 3 is established by disengaging both the forward clutch 10b and the reverse brake 10c. Therefore, by operating the forward / reverse switching mechanism 10, the shift range of the belt-type continuously variable transmission 3 is switched between at least the "driving ranges" of the D (drive) range and the R (reverse) range and the "non-driving range" of the N (neutral) range.

[0028] The oil pump 11 is a "mechanical oil pump" that generates hydraulic pressure when driven by the output torque of the engine 1. The hydraulic pressure generated by the oil pump 11 is supplied to the hydraulic cylinder 7c of the primary pulley 7 and the hydraulic cylinder 8c of the secondary pulley 8 via a hydraulic control device, and the speed ratio control and the belt clamping pressure control of the belt-type continuously variable transmission 3 are performed.

[0029] 1 has basically the same configuration as the "belt-type continuously variable transmission" shown in "Fig. 1" of the above-mentioned Patent Document 1 or, for example, "Fig. 4" of Japanese Patent Application Laid-Open No. 2014-62596. Therefore, detailed explanations of the configurations of the various parts of the belt-type continuously variable transmission 3 are the same as those explained in the specification of Patent Document 1 and the specification of Japanese Patent Application Laid-Open No. 2014-62596.

[0030] The detection unit 4 is a device or apparatus for acquiring various data and information required to control the vehicle Ve, and includes, for example, a power supply unit, a microcomputer, a sensor, an input / output interface, etc. In particular, the detection unit 4 in this embodiment of the present invention detects various data for controlling the belt-type continuously variable transmission 3. For example, the detection unit 4 includes various sensors and devices such as a vehicle speed sensor 4a that detects the vehicle speed, an acceleration sensor 4b that detects the acceleration of the vehicle Ve, an oil pressure sensor 4c that detects the oil pressure (primary sheave pressure) acting on the movable sheave 7b and the oil pressure (secondary sheave pressure) acting on the movable sheave 8b, a rotation speed sensor 4d that detects the engine speed, the rotation speed of the input shaft 3a (or primary pulley 7), and the rotation speed of the output shaft 3b (or secondary pulley 8), an oil temperature sensor 4e that detects the oil temperature of the belt-type continuously variable transmission 3 (specifically, the temperature of the oil discharged from the oil pump 11), an accelerator opening sensor 4f that detects the amount of depression of the accelerator pedal (not shown) (or accelerator opening), and a shift position sensor 4g that detects the shift position of a shift device (not shown) that switches the shift range of the belt-type continuously variable transmission 3. The detection unit 4 is electrically connected to the control unit 5 described later, and outputs electrical signals and the like corresponding to the detected or calculated values ​​of the various sensors, devices, and apparatuses described above to the control unit 5 as detection data.

[0031] The control unit 5 is an electronic control device mainly composed of, for example, a microcomputer. In this embodiment of the present invention, the control unit 5 controls the vehicle Ve, particularly the belt-type continuously variable transmission 3. The control unit 5 receives various data detected or calculated by the detection unit 4. The control unit 5 performs calculations using the received data, pre-stored data, calculation formulas, and the like. The control unit 5 then outputs the calculation results as control command signals to control the vehicle Ve as described above. Specifically, the control unit 5 outputs a command pressure (hydraulic pressure command value) for the primary sheave pressure to the hydraulic control device of the belt-type continuously variable transmission 3, thereby controlling the gear ratio of the belt-type continuously variable transmission 3. The control unit 5 also outputs a command pressure (hydraulic pressure command value) for the secondary sheave pressure, thereby controlling the belt clamping pressure of the belt-type continuously variable transmission 3. While FIG. 1 shows an example in which one control unit 5 is provided, multiple control units 5 may be provided for each device or equipment to be controlled or for each control content.

[0032] As described above, in a vehicle Ve equipped with the above-described belt-type continuously variable transmission 3, when a so-called garage shift is performed, in which the shift range is switched between D range or R range and N range while traveling at a low vehicle speed, a fail-safe valve (not shown) is used to set the command pressure of the primary sheave pressure higher than normal, thereby controlling the gear ratio. As a result, the gear ratio of the belt-type continuously variable transmission 3 is set to a higher value than normal. Furthermore, when the vehicle Ve is traveling at an extremely low vehicle speed, the rotation speed of the output shaft 3b of the belt-type continuously variable transmission 3 cannot be accurately detected, so the gear ratio is controlled by feedforward control rather than feedback control. In this case, if the oil temperature becomes high and the amount of oil discharged by the oil pump 11 decreases, the actual secondary sheave pressure (actual pressure) will fall short of the command pressure of the secondary sheave pressure, which may result in an imbalance between the primary sheave pressure and the secondary sheave pressure being shifted to the upshift side.

[0033] For example, as shown in the time chart of Figure 2, after time t1, while the "vehicle" is traveling at a low vehicle speed, if the shift range of the "belt-type continuously variable transmission" is switched from N range to D range or R range at time t2 (i.e., garage shift is performed), hydraulic pressure is output by a failsafe valve (not shown), making normal gear ratio control impossible and causing the gear ratio of the "belt-type continuously variable transmission" to decrease. In other words, the "belt-type continuously variable transmission" essentially upshifts.

[0034] Furthermore, if the oil temperature rises and the oil pump discharge rate decreases during low-speed driving, the actual primary sheave pressure (actual primary pressure) falls short of the target primary sheave pressure (target primary pressure). As a result, the balance between the primary sheave pressure and the secondary sheave pressure is disrupted, causing the belt-type continuously variable transmission to upshift. When the vehicle speed exceeds a predetermined low speed (e.g., 2 km / h) at time t3, feedback control of the gear ratio becomes possible, and the gear ratio of the belt-type continuously variable transmission gradually returns to the target gear ratio or maximum gear ratio. However, if a garage shift such as the one described above is performed or if the vehicle speed remains below the predetermined low speed, an unintended upshift such as the one described above may occur between time t2 and time t4, potentially resulting in insufficient driving force for the vehicle.

[0035] Therefore, in the vehicle control device according to the embodiment of the present invention, even when the above-described garage shift is performed, in order to appropriately perform the gear ratio control of the belt-type continuously variable transmission 3, the control shown in the flowchart of FIG. 3 is performed.

[0036] In the flowchart of Figure 3, first, in step S1, it is determined whether a shift operation has been performed while the vehicle Ve is traveling, specifically, whether a garage shift has been performed by the driver's shift operation while the vehicle Ve is traveling at a predetermined low vehicle speed, in which the shift range of the belt-type continuously variable transmission 3 is switched between a driving range (i.e., D range and R range) and a non-driving range (i.e., N range).

[0037] If the garage shift has not yet been performed and therefore the answer is "No" in step S1, the process proceeds to step S2.

[0038] In step S2, the garage shift flag is turned OFF. If the garage shift flag is already OFF, the OFF state is maintained. At the same time, the idling speed of the engine 1 is controlled to a normal speed (normal idle speed) when a garage shift is not being performed. The garage shift flag is a control flag that is turned "ON" when the execution of a garage shift as described above is detected or determined, and is turned "OFF" when the end of a garage shift is detected or determined, as will be described later, or when the end of idle-up control, which will be described later, is detected or determined.

[0039] In step S2, the garage shift flag is turned OFF and the engine 1 is controlled at a normal idling speed, after which the routine shown in the flowchart of FIG. 3 is temporarily terminated.

[0040] On the other hand, if a garage shift has been performed by the driver's shift operation and the answer is "Yes" in step S1, the process proceeds to step S3.

[0041] In step S3, it is determined whether the oil temperature is equal to or higher than the oil temperature threshold value A. Specifically, it is determined whether the temperature of the oil (oil temperature) discharged by the oil pump 11 is equal to or higher than the oil temperature threshold value A. The oil temperature threshold value A is a threshold value for determining a state in which the discharge performance of the oil pump 11 is reduced, and is set in advance based on, for example, the results of a running experiment using an actual vehicle or a simulation.

[0042] If the oil temperature is lower than the oil temperature threshold A and the determination in step S3 is "No," the process proceeds to step S2, where the same control as before is executed, and then the routine shown in the flowchart of FIG. 3 is temporarily ended.

[0043] On the other hand, if the oil temperature is equal to or higher than the oil temperature threshold A and therefore the determination in step S3 is "Yes," the process proceeds to step S4.

[0044] In step S4, the garage shift flag is turned ON. At the same time, the idle-up of the engine 1 is performed. Specifically, the idling speed of the engine 1 is temporarily increased above the idling speed set in normal times when no garage shift is being performed (the normal idle speed set in step S2 above). That is, the execution of the idle-up control in this embodiment of the present invention is started.

[0045] When the above-described idle-up control is started in step S4, the conditions for ending the idle-up control are determined in the following steps S5 and S6.

[0046] In step S5, it is determined whether the vehicle speed is higher than vehicle speed threshold B. Vehicle speed threshold B is a predetermined low vehicle speed, for example, about 2 km / h as mentioned above, and is set in advance based on the results of running experiments using an actual vehicle, simulations, etc., as a threshold for determining a state in which gear ratio control by feedback control becomes possible.

[0047] If the vehicle speed is still equal to or less than the vehicle speed threshold B and therefore the determination in step S5 is "No," the control in step S5 is executed again. That is, the control in step S5 is repeated until the vehicle speed becomes higher than the vehicle speed threshold B.

[0048] On the other hand, if the vehicle speed is higher than the vehicle speed threshold B and therefore the answer is "Yes" in step S5, the process proceeds to step S6.

[0049] In step S6, it is determined whether the gear ratio (actual gear ratio) of the belt-type continuously variable transmission 3 has returned to the maximum gear ratio (γmax) or whether the actual gear ratio of the belt-type continuously variable transmission 3 is following the target gear ratio in the gear ratio control. In other words, since the vehicle speed has exceeded vehicle speed threshold B, feedback control of the gear ratio control is possible, and it is determined whether the actual gear ratio of the belt-type continuously variable transmission 3 has become the maximum gear ratio or the target gear ratio.

[0050] If the actual speed ratio of the belt-type continuously variable transmission 3 has not yet returned to the maximum speed ratio or the target speed ratio and therefore the determination in step S6 is "No," the controls in steps S5 and S6 are executed again. That is, the controls in steps S5 and S6 are repeated until the vehicle speed becomes higher than the vehicle speed threshold B and the actual speed ratio of the belt-type continuously variable transmission 3 returns to the maximum speed ratio or the target speed ratio.

[0051] If the actual speed ratio of the belt-type continuously variable transmission 3 has returned to the maximum speed ratio or the target speed ratio and the answer to step S6 is "Yes," the process proceeds to step S2, where the same control as before is executed. That is, in this case, the execution of the above-described idle-up control is terminated, and the garage shift flag is set to OFF. Then, the routine shown in the flowchart of FIG. 3 is temporarily terminated.

[0052] 4, after time t11, while the vehicle Ve is traveling at a low vehicle speed, when the shift range of the belt-type continuously variable transmission 3 is switched from N range to D range or R range at time t12 (i.e., a garage shift is performed), the control unit 5 in this embodiment of the present invention turns on the garage shift flag and starts executing idle-up control to temporarily increase the idling speed of the engine 1. By increasing the idling speed of the engine 1, the discharge amount of the oil pump 11 is ensured, and the shortage of the actual primary sheave pressure (actual primary pressure) relative to the target value of the primary sheave pressure (target primary pressure) is resolved.

[0053] Before time t11, when the idle-up control is started, a deviation occurs between the target primary pressure and the actual primary pressure, causing the belt-type continuously variable transmission 3 to upshift and temporarily reduce the gear ratio. In contrast, in the control unit 5 according to the embodiment of the present invention, by executing the idle-up control, the discharge rate of the oil pump 11 increases, and the belt clamping pressure of the belt-type continuously variable transmission 3 can be output as desired. Therefore, the gear ratio that has decreased after time t11 due to the unintended upshift described above can be immediately returned to the target gear ratio or the maximum gear ratio.

[0054] Then, the actual speed ratio of the belt-type continuously variable transmission 3 returns to the target speed ratio or the maximum speed ratio, and at time t13, the vehicle speed becomes equal to or greater than the vehicle speed threshold B, so the execution of the idle-up control is terminated. At the same time, the garage shift flag is turned OFF.

[0055] As described above, in the vehicle control device according to the embodiment of the present invention, when a garage shift is performed while the vehicle Ve is traveling at a low vehicle speed, the vehicle control device executes idle-up control, temporarily idling the engine 1 at a higher rotational speed than normal. By raising the idling rotational speed of the engine 1, the discharge volume of the oil pump 11 can be ensured and an appropriate oil pressure can be obtained, thereby controlling the belt clamping pressure of the belt-type continuously variable transmission 3 as desired. Therefore, even if the belt-type continuously variable transmission 3 operates toward the upshift side during the above-described garage shift, it can be quickly returned to the maximum gear ratio or the target gear ratio.

[0056] Therefore, according to the vehicle control device of this embodiment of the present invention, even when a vehicle Ve equipped with a belt-type continuously variable transmission 3 performs garage shifting at a low vehicle speed, the gear ratio control of the belt-type continuously variable transmission 3 can be appropriately performed, and an appropriate driving force can be generated to allow the vehicle Ve to travel. [Explanation of symbols]

[0057] 1 Engine (ENG) 2 drive wheels 3 Belt-type continuously variable transmission 3a (Belt-type continuously variable transmission) input shaft 3b (Belt type continuously variable transmission) output shaft 4. Detection unit 4a (detection part) vehicle speed sensor 4b Acceleration sensor (detection section) 4c Oil pressure sensor (detection part) 4d (detection part) rotation speed sensor 4e Oil temperature sensor (detection section) 4f (Detection section) Accelerator opening sensor 4g Shift position sensor (detection part) 5 Control Unit (ECU) 6 Torque converter 7 Primary pulley 7a Fixed sheave (of primary pulley) 7b Movable sheave (of primary pulley) 7c Hydraulic cylinder (primary pulley) 8 Secondary pulley 8a Fixed sheave (of secondary pulley) 8b (Secondary pulley) movable sheave 8c Hydraulic cylinder (secondary pulley) 9 Transmission belt 10 Forward / reverse switching mechanism 10a Planetary gear mechanism (for forward / reverse switching mechanism) 10b Forward clutch (C1) (for forward / reverse switching mechanism) 10c Reverse brake (B1) 11 Oil pump Vehicle

Claims

[Claim 1] A control device for a vehicle including an engine, a belt-type continuously variable transmission having a primary pulley and a secondary pulley around which a transmission belt is wound, and transmitting engine torque output by the engine to drive wheels, and an oil pump driven by the engine, wherein a primary sheave pressure supplied to the primary pulley and a secondary sheave pressure supplied to the secondary pulley are hydraulically controlled using oil pressure generated by the oil pump, and belt clamping pressure control and gear ratio control of the belt-type continuously variable transmission, a control unit for controlling the belt-type continuously variable transmission; The control unit When a garage shift is performed by a driver during driving, in which the shift range of the belt-type continuously variable transmission is repeatedly switched between a driving range in which the engine torque is transmitted to the driving wheels and a non-driving range in which the engine torque is not transmitted to the driving wheels, an idle-up control is executed to temporarily increase the idling speed of the engine above the idling speed set in normal times when the garage shift is not being performed. A vehicle control device comprising:

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