Abstract: A hydraulic control circuit includes a pressure regulator valve, a first pilot valve, a second pilot valve, and a third pilot valve. A first pilot pressure is introduced as a source pressure into the primary solenoid valve that generates a primary signal pressure and a secondary solenoid valve that generates a secondary signal pressure. A second pilot pressure is introduced as a source pressure into a lock-up solenoid valve that generates the lock-up signal pressure. A third pilot pressure is introduced as a damping pressure into a primary regulator valve that controls a primary pulley pressure according to the primary signal pressure, and into a secondary regulator valve that controls a secondary pulley pressure according to the secondary signal pressure.

Abstract: A valve arrangement structure of a control valve unit includes a control valve body to which oil is supplied from a main pump. The valve arrangement structure includes a pressure regulator valve that is arranged in the control valve body and regulates a pressure of discharged oil from the main pump to a line pressure, a pressure control valve that is arranged in the control valve body and regulates the pressure of the oil to a required pressure with the line pressure as a source pressure, and a first oil passage that is provided in the control valve body and connects the main pump and the pressure regulator valve. The pressure control valve is arranged on a second oil passage branched from the first oil passage.

Abstract: A hydraulic control circuit includes a pressure regulator valve, a first pilot valve, a second pilot valve, and a third pilot valve. A first pilot pressure is introduced as a source pressure into the primary solenoid valve that generates a primary signal pressure and a secondary solenoid valve that generates a secondary signal pressure. A second pilot pressure is introduced as a source pressure into a lock-up solenoid valve that generates the lock-up signal pressure. A third pilot pressure is introduced as a damping pressure into a primary regulator valve that controls a primary pulley pressure according to the primary signal pressure, and into a secondary regulator valve that controls a secondary pulley pressure according to the secondary signal pressure.

Abstract: A CVTECU includes a secondary-pressure control section and a line-pressure control section that performs a same-pressure control to equalize a line pressure and a secondary pressure with each other if a predetermined start condition is satisfied. The line-pressure control section realizes a same-pressure state between the line pressure and the secondary pressure by lowering the line pressure below a target secondary pressure, and then controls the line pressure such that an actual secondary pressure is brought to the target secondary pressure by hydraulic feedback control while maintaining the same-pressure state. The secondary-pressure control section includes a restriction section that restricts an accumulation of integral term of an integral action for a duration between a time point at which the actual secondary pressure starts to be pushed down and a time point at which the same-pressure state between the line pressure and the secondary pressure is realized.

Abstract: In a hydraulic control circuit including a solenoid valve, whose change responsiveness in an actual pressure with respect to a change in an instructional pressure deteriorates when the instructional pressure enters a dead band region on a lower pressure side than a dead band threshold, for adjusting a hydraulic pressure supplied to a hydraulic device operated by the hydraulic pressure based on the instructional pressure, the instructional pressure is increased in a stepwise manner to a charge pressure higher than the dead band threshold, when the instructional pressure is set in the dead band region and the instructional pressure increases within the dead band region to such an extent that a speed ratio does not change. Then, a lower limit of the instructional pressure is set to the dead band threshold, and use of the dead band region is prohibited for a certain period of time.

Abstract: A CVTECU includes a secondary-pressure control section and a line-pressure control section that performs a same-pressure control to equalize a line pressure and a secondary pressure with each other if a predetermined start condition is satisfied. The line-pressure control section realizes a same-pressure state between the line pressure and the secondary pressure by lowering the line pressure below a target secondary pressure, and then controls the line pressure such that an actual secondary pressure is brought to the target secondary pressure by hydraulic feedback control while maintaining the same-pressure state. The secondary-pressure control section includes a restriction section that restricts an accumulation of integral term of an integral action for a duration between a time point at which the actual secondary pressure starts to be pushed down and a time point at which the same-pressure state between the line pressure and the secondary pressure is realized.

Abstract: A transmission controller determines whether a shift is a kickdown, and when the shift is determined as the kickdown, the target line pressure is increased to a first target pressure corresponding to an input torque to a continuously variable transmission increased by the kickdown; the transmission controller then determines whether the line pressure has reached the first target pressure, and if determined that the line pressure has reached the first target pressure, the target line pressure is increased to a second target pressure higher than the first target pressure.

Abstract: A target primary pressure and a target secondary pressure are set based on a speed ratio, a target line pressure as a target value of a line pressure is set to be a value obtained by adding an offset amount, as a positive value, to either one having a higher value out of the target primary pressure and the target secondary pressure, in at least a cross-point region as a region where an absolute value of a deviation, obtained by subtracting the target primary pressure from the target secondary pressure, is smaller than a predetermined deviation, and a primary pressure, a secondary pressure, and the line pressure are controlled to be the target primary pressure, the target secondary pressure, and the target line pressure, respectively.

Abstract: A transmission controller determines whether a shift is a kickdown, and when the shift is determined as the kickdown, the target line pressure is increased to a first target pressure corresponding to an input torque to a continuously variable transmission increased by the kickdown; the transmission controller then determines whether the line pressure has reached the first target pressure, and if determined that the line pressure has reached the first target pressure, the target line pressure is increased to a second target pressure higher than the first target pressure.

Abstract: A target primary pressure and a target secondary pressure are set based on a speed ratio, a target line pressure as a target value of a line pressure is set to be a value obtained by adding an offset amount, as a positive value, to either one having a higher value out of the target primary pressure and the target secondary pressure, in at least a cross-point region as a region where an absolute value of a deviation, obtained by subtracting the target primary pressure from the target secondary pressure, is smaller than a predetermined deviation, and a primary pressure, a secondary pressure, and the line pressure are controlled to be the target primary pressure, the target secondary pressure, and the target line pressure, respectively.

Abstract: In a hydraulic control circuit including a solenoid valve, whose change responsiveness in an actual pressure with respect to a change in an instructional pressure deteriorates when the instructional pressure enters a dead band region on a lower pressure side than a dead band threshold, for adjusting a hydraulic pressure supplied to a hydraulic device operated by the hydraulic pressure based on the instructional pressure, the instructional pressure is increased in a stepwise manner to a charge pressure higher than the dead band threshold, when the instructional pressure is set in the dead band region and the instructional pressure increases within the dead band region to such an extent that a speed ratio does not change. Then, a lower limit of the instructional pressure is set to the dead band threshold, and use of the dead band region is prohibited for a certain period of time.

Abstract: In hydraulic pressure control apparatus and method for a continuously variable transmission, a line pressure of the continuously variable transmission is developed with a working oil supplied from an oil pump as an original pressure, and a command pressure is set to develop a line pressure target value of the target value in such a manner that the command pressure is maintained at a predetermined small value for a constant time and, thereafter, the value of the command pressure is raised up to the target value when a shift range of the continuously variable transmission is switched from a neutral range to a running range, the command pressure being raised at a rate lower than a step input to suppress an overshoot developed in the actual line pressure.

Abstract: A hydraulic control apparatus for an automatic transmission with a line pressure regulator valve operative to regulate an oil pressure produced by an oil pump and set a line pressure, the hydraulic control apparatus including a control unit outputting a first command for controlling the line pressure regulator valve to set the line pressure to a minimum value immediately after engine start, and a second command for controlling the line pressure regulator valve to set the line pressure to a target value in accordance with increase in engine speed. The control unit is programmed to set the target value of the line pressure to a value smaller than a maximum value of the line pressure and/or reduce a target speed of engine speed, upon start of the engine in a low temperature condition.

Abstract: A belt-type continuously variable transmission having a forward clutch is incorporated with a speed-changing hydraulic pressure control system. The control system includes an engaging pressure regulating device for outputting an engaging pressure for the forward clutch. An electronically controlled hydraulic pressure control valve is provided to output a signal pressure which is able to cause the engaging pressure regulating device to set the engaging pressure. A control unit is provided to output a control command signal to the hydraulic pressure control valve, the control command signal causing the hydraulic pressure control valve to output the signal pressure. Here, the engaging pressure regulating device is arranged to output a minimum value of the engaging pressure in response to a maximum value of the signal pressure from the hydraulic pressure control valve, and to output a maximum value of the engaging pressure in response to a minimum value of the signal pressure.

Abstract: In control apparatus and method for an automotive vehicle, the vehicle having a continuously variable transmission associated with a vehicular engine and including a belt that transmits a revolution of a primary pulley to a secondary pulley that is enabled to make a gear shift by modifying a pulley ratio between the primary and secondary pulleys with a hydraulic, a determination is made as to whether a belt slip between at least one of the primary and the secondary pulleys occurs and an output section outputs a signal to command an engine control unit to increase an engine speed by a predetermined engine speed when the belt slip is determined to occur.

Abstract: Hydraulic control apparatus includes a belt-drive CVT, a pressure regulator valve (P.REG.V) regulating the oil pressure produced by an oil pressure source, a controller programmed to develop a transmission control signal, a transmission actuator driven based on the signal, and a transmission control valve actuated by the actuator. There are provided a first oil passage for supplying an oil pressure regulated by the P.REG.V, a second oil passage for supplying the oil pressure regulated to a primary pulley cylinder chamber of the CVT and draining the oil pressure therefrom, a third oil passage for draining the oil pressure within the cylinder chamber, and a fourth oil passage downstream of the P.REG.V. The third and fourth oil passages are connected to supply an oil pressure to the cylinder chamber and establish a minimum oil pressure required for clamping the belt depending on reduction of the oil pressure within the cylinder chamber.

Abstract: In hydraulic pressure control apparatus and method for a continuously variable transmission, a line pressure of the continuously variable transmission is developed with a working oil supplied from an oil pump as an original pressure, and a command pressure is set to develop a line pressure target value of the target value in such a manner that the command pressure is maintained at a predetermined small value for a constant time and, thereafter, the value of the command pressure is raised up to the target value when a shift range of the continuously variable transmission is switched from a neutral range to a running range, the command pressure being raised at a rate lower than a step input to suppress an overshoot developed in the actual line pressure.

Abstract: A hydraulic control apparatus for an automatic transmission with a line pressure regulator valve operative to regulate an oil pressure produced by an oil pump and set a line pressure, the hydraulic control apparatus including a control unit outputting a first command for controlling the line pressure regulator valve to set the line pressure to a minimum value immediately after engine start, and a second command for controlling the line pressure regulator valve to set the line pressure to a target value in accordance with increase in engine speed. The control unit is programmed to set the target value of the line pressure to a value smaller than a maximum value of the line pressure and/or reduce a target speed of engine speed, upon start of the engine in a low temperature condition.

Abstract: A belt-type continuously variable transmission having a forward clutch is incorporated with a speed-changing hydraulic pressure control system. The control system includes an engaging pressure regulating device for outputting an engaging pressure for the forward clutch. An electronically controlled hydraulic pressure control valve is provided to output a signal pressure which is able to cause the engaging pressure regulating device to set the engaging pressure. A control unit is provided to output a control command signal to the hydraulic pressure control valve, the control command signal causing the hydraulic pressure control valve to output the signal pressure. Here, the engaging pressure regulating device is arranged to output a minimum value of the engaging pressure in response to a maximum value of the signal pressure from the hydraulic pressure control valve, and to output a maximum value of the engaging pressure in response to a minimum value of the signal pressure.

Abstract: In corrective control system and method for a liquid pressure control apparatus for a control valve unit, fundamental maps are preset on the basis of a hysteresis characteristic, the hysterisis characteristic being exhibited in such a manner that an output liquid pressure actually measured value which takes along a first hysterisis loop when the current value is increased toward a larger value is different from that which takes along a second hysterisis loop when the current value is, in turn, decreased toward a smaller value from the larger value and the fundamental maps uses a relationship on a derived first-order function at a lower output pressure side than a linear region of the hysterisis characteristic.