Abstract: A hydraulic pressure control device is provided that that controls hydraulic pressure of a clutch supplying torque to a continuously variable transmission while the vehicle is stopped and in a running range. The hydraulic pressure control device has an control section that estimates a clutch engagement hydraulic pressure for the clutch based on initially rotational movement of a primary pulley of the continuously variable transmission, and then controls regulation of the hydraulic pressure to the clutch to a designated pressure that is no greater than the clutch engagement hydraulic pressure, when the vehicle is stopped and in the running range, so that the torque from the engine does not rotate a secondary pulley of the continuously variable transmission.

Abstract: A hydraulic pressure control device is provided that that controls hydraulic pressure of a clutch supplying torque to a continuously variable transmission while the vehicle is stopped and in a running range. The hydraulic pressure control device has an control section that estimates a clutch engagement hydraulic pressure for changing the clutch from an engaged state to a disengaged state based the hydraulic fluid pressure acting on the clutch during the stopping of the rotational movement of a primary pulley of the continuously variable transmission, and then controls regulation of the hydraulic pressure to the clutch from an engaged state to a disengaged state, when the vehicle is stopped and in the running range, so that the torque from the engine does not rotate a secondary pulley of the continuously variable transmission.

Abstract: A hydraulic pressure control device is provided to control hydraulic fluid pressure supplied to pulleys of a continuously variable transmission to change a gear ratio. A line pressure regulating component is controlled by a hydraulic CVT controller to regulate line pressure from a hydraulic fluid pump. A secondary pressure regulating component regulates the line pressure to supply a target pressure to the secondary pulley such that the target pressure increases as the signal pressure increases. A signal pressure regulating component adjusts the signal pressure by draining the hydraulic fluid from a pilot line pressure such that the signal pressure increases as the aperture size of the solenoid valve increases. The signal pressure regulating component regulates the signal pressure so that the target pressure supplied to the secondary pulley is at a maximum from a time the forward clutch is released to a time the forward clutch is re-engaged.

Abstract: Hydraulic control system and method for a belt-drive continuously variable transmission (CVT). The system includes an oil pump operative to produce an oil pressure and an oil flow amount which are supplied to the CVT, a pressure regulator valve operative to regulate the oil pressure, an oil supply passage for supplying oil to the belt on a downstream side of the pressure regulator valve, means for detecting an engine operating condition and generating a signal indicative of the engine operating condition detected, and a controller programmed to calculate a CVT input torque based on the signal, calculate a required belt lubricating oil flow amount to be supplied to the belt on the basis of the signal and the CVT input torque, determine a minimum speed of the oil pump based on the required belt lubricating oil flow amount, and control the oil pump at the minimum speed.

Abstract: A system for controlling a hydraulic pressure of an automatic transmission includes a torque converter having a lockup clutch for direct coupling between an engine and the transmission, a lockup solenoid valve for providing a signal pressure for controlling engagement of the lockup clutch, a lockup control valve for providing an engagement pressure to the lockup clutch in accordance with the signal pressure, and a CVT control unit for controlling the lockup solenoid valve. The CVT control unit is programmed to determine torque provided to the torque converter and control the signal pressure in accordance with the torque.

Abstract: Disclosed is a control device for controlling a two-way linear solenoid valve (60) including a pressure regulating port (60p) which communicates with a hydraulic circuit side, a drain port (60d) which communicates with a drain side, a plunger (61) which controls the state of communication between the pressure regulating port and drain port, and a coil (70) which drives the plunger in accordance with an exciting current. The control device has a current generator (65) which supplies the coil with the exciting current corresponding to a duty signal; and a microcomputer (1). The microcomputer determines whether or not a preset foreign matter removal starting condition for removing foreign matter accumulated in the ports has been established.

Abstract: Disclosed is a control device for controlling a two-way linear solenoid valve (60) including a pressure regulating port (60p) which communicates with a hydraulic circuit side, a drain port (60d) which communicates with a drain side, a plunger (61) which controls the state of communication between the pressure regulating port and drain port, and a coil (70) which drives the plunger in accordance with an exciting current. The control device has a current generator (65) which supplies the coil with the exciting current corresponding to a duty signal; and a microcomputer (1). The microcomputer determines whether or not a preset foreign matter removal starting condition for removing foreign matter accumulated in the ports has been established.

Abstract: In a transmission-fluid cooling system of an automatic transmission of an automotive vehicle equipped with a water-cooled oil cooler and an air-cooled oil cooler connected in series to each other, a first bypass valve is provided to permit working fluid to circulate therevia through oil passages in the transmission, bypassing the water-cooled oil cooler and the air-cooled oil cooler, only when a working-fluid temperature is less than or equal to a predetermined temperature and the line pressure is greater than or equal to a predetermined pressure. Also provided is a second bypass valve that opens to permit the working fluid to circulate via the water-cooled oil cooler and the second bypass valve through the oil passages in the transmission, bypassing only the air-cooled oil cooler, only when the working-fluid temperature is less than or equal to a preset temperature value.

Abstract: In a transmission-fluid cooling system of an automatic transmission of an automotive vehicle equipped with a water-cooled oil cooler and an air-cooled oil cooler connected in series to each other, a first bypass valve is provided to permit working fluid to circulate therevia through oil passages in the transmission, bypassing the water-cooled oil cooler and the air-cooled oil cooler, only when a working-fluid temperature is less than or equal to a predetermined temperature and the line pressure is greater than or equal to a predetermined pressure. Also provided is a second bypass valve that opens to permit the working fluid to circulate via the water-cooled oil cooler and the second bypass valve through the oil passages in the transmission, bypassing only the air-cooled oil cooler, only when the working-fluid temperature is less than or equal to a preset temperature value.

Abstract: In a transmission-fluid cooling system of an automatic transmission of an automotive vehicle equipped with a water-cooled oil cooler and an air-cooled oil cooler connected in series to each other, a first bypass valve is provided to permit working fluid to circulate therevia through oil passages in the transmission, bypassing the water-cooled oil cooler and the air-cooled oil cooler, only when a working-fluid temperature is less than or equal to a predetermined temperature and the line pressure is greater than or equal to a predetermined pressure. Also provided is a second bypass valve that opens to permit the working fluid to circulate via the water-cooled oil cooler and the second bypass valve through the oil passages in the transmission, bypassing only the air-cooled oil cooler, only when the working-fluid temperature is less than or equal to a preset temperature value.

Abstract: A system for controlling a hydraulic pressure of an automatic transmission includes a torque converter having a lockup clutch for direct coupling between an engine and the transmission, a lockup solenoid valve for providing a signal pressure for controlling engagement of the lockup clutch, a lockup control valve for providing an engagement pressure to the lockup clutch in accordance with the signal pressure, and a CVT control unit for controlling the lockup solenoid valve. The CVT control unit is programmed to determine torque provided to the torque converter and control the signal pressure in accordance with the torque.

Abstract: Hydraulic control system and method for a belt-drive continuously variable transmission (CVT). The system includes an oil pump operative to produce an oil pressure and an oil flow amount which are supplied to the CVT, a pressure regulator valve operative to regulate the oil pressure, an oil supply passage for supplying oil to the belt on a downstream side of the pressure regulator valve, means for detecting an engine operating condition and generating a signal indicative of the engine operating condition detected, and a controller programmed to calculate a CVT input torque based on the signal, calculate a required belt lubricating oil flow amount to be supplied to the belt on the basis of the signal and the CVT input torque, determine a minimum speed of the oil pump based on the required belt lubricating oil flow amount, and control the oil pump at the minimum speed.

Abstract: In a transmission-fluid cooling system of an automatic transmission of an automotive vehicle equipped with a water-cooled oil cooler and an air-cooled oil cooler connected in series to each other, a first bypass valve is provided to permit working fluid to circulate therevia through oil passages in the transmission, bypassing the water-cooled oil cooler and the air-cooled oil cooler, only when a working-fluid temperature is less than or equal to a predetermined temperature and the line pressure is greater than or equal to a predetermined pressure. Also provided is a second bypass valve that opens to permit the working fluid to circulate via the water-cooled oil cooler and the second bypass valve through the oil passages in the transmission, bypassing only the air-cooled oil cooler, only when the working-fluid temperature is less than or equal to a preset temperature value.