Abstract: A motor-driven power steering system for a vehicle and a method for controlling the same in which the assisting torque of a motor is transmitted through a clutch toward steerable road wheels of the vehicle for power assisting the steering motion imparted to a steering wheel by an operator. It is possible to precisely judge whether there exists a failure in the operation of the motor and/or the clutch before the clutch is connected. To this end, a certain characteristic value of the motor under no load condition is measured with the clutch disconnected, and then compared with a preset comparison value such as a reference motor current to determine whether the motor is mechanically restricted. If not, the clutch is connected. If so, the clutch is kept not connected so that an appropriate failsafe operation can be performed.

Abstract: An apparatus for controlling a continuously variable vehicle transmission includes a fixed pulley member and a movable pulley member which is supported for movement toward and away from the fixed pulley member. A groove defined between the pulley members has a width which is decreased and increased to thereby respectively increase and decrease the rotational radius of a belt which is received in the groove. A control arrangement executes speed change control to change the belt ratio. The control arrangement includes a control unit which receives throttle opening degree and vehicle velocity detection signals and determines first and second target engine rotational speed which are based respectively on these detection signals. The control unit determines an optimum target engine rotational speed based on the firt and second target engine rotational speeds and sets upper and lower limit values of the optimum target engine rotational speed in accordance with predetermined conditions.

Abstract: A method for controlling a continuously variable transmission having a pair of pulleys each of which includes a groove defined between a stationary pulley element and a movable pulley element, including the step of using hydraulic oil for increasing and decreasing the width of the groove to respectively decrease and increase the radius of rotation of a belt looped around the pulleys to thereby vary the belt ratio. A hydraulic clutch is provided, and connection and disconnection of the clutch is controlled according to various predetermined control modes. Line pressure is controlled with a control device which uses both open loop control, and closed loop feedback control responsive to a signal from a pressure sensor. During open loop control, the line pressure is controlled so as to reflect the clutch pressure during a vehicle start mode.

Abstract: A continuously variable transmission which effects a speed change by increasing and decreasing the width of a groove between a fixed pulley part and a movable pulley part. A belt ratio controller for the transmission uses oil pressure to increase and decrease the rotating radius of a belt wound on the pulley parts, the belt controller controlling the belt ratio to a target belt ratio value set based on the opening of the throttle when starting on a road having a small road surface friction coefficient.

Abstract: A method and apparatus for controlling a continuous speed variable transmission includes a pressure sensor for detecting atmospheric pressure, and a control unit which receives a detection signal from the pressure sensor. The control unit responds to the detected atmospheric pressure, the shift position of the transmission, and other predetermined conditions to correct clutch pressure and line pressure.

Abstract: A method of controlling the rotational speed of a continuously variable transmission having a pair of pulleys which each includes a fixed pulley member and a movable pulley member, including the steps of decreasing and increasing the groove width between each pair of fixed and movable pulley members to respectively increase and decrease the rotational radius of a belt wrapped around the pulleys. A hydraulic clutch is provided and is connected to and disconnected from the driving force of the transmission in response to clutch pressure applied thereto. A control section is provided for calculating a desired clutch pressure for the hydraulic clutch. This desired clutch pressure is based on an engine torque value and a desired engine rotational speed. When the clutch is in a normal starting mode and certain other predetermined conditions are satisfied, the control section is used to adjust the desired engine rotational speed based on the temperature of the oil in the transmission.

Abstract: A continously variable transmission has a fixed pulley piece and has a movable pulley piece which is supported for movement toward and away from the fixed pulley piece, the width of a groove between the pulley pieces being increased or decreased in order to increase or decrease the radius of rotation of a belt looped around a driving side pulley and a driven side pulley which include the fixed and movable pulley pieces to thereby vary a belt ratio. A hydraulic clutch is engaged and disengaged under control of a clutch pressure in order to vary a driving force output by the continuously variable transmission, and a control arrangement controls and hydraulic clutch so that creep caused by slippage of the hydraulic clutch in a hold mode during a reverse gear operation of the continuously variable transmission is larger than creep caused by slippage of the hydraulic clutch in a hold mode during forward gear operation of the continuously variable transmission.

Abstract: A method of controlling a continuously variable transmission which includes a fixed pulley member and a movable pulley member supported relative to the fixed pulley member so as to be movable both toward and away from the fixed pulley member, including the steps of decreasing and increasing the width of a groove defined between the pulley members to thereby respectively increase and decrease a rotational radius of a belt which is received between the pulley members in the groove. When a target engine rotational speed based on throttle opening degree and vehicle velocity changes during vehicle running, a transient speed change control is performed so as to change a belt ratio of the transmission based on a predetermined rate limit value. A control unit is provided for receiving the throttle opening degree and vehicle velocity and executing the transient speed change control.

Abstract: A hydraulic control method is applied to a continuously variable speed change gear mechanism including a pulley having a fixed pulley member fixed to a rotary shaft and a movable pulley member movable by oil pressure toward and away from the fixed pulley member so that a groove width between the fixed and movable pulley members is decreased or increased to thereby reduce or increase the effective rotational radius of a belt extending between the pulley members and thus change a change gear ratio and control the gear change.

Abstract: A continuously variable transmission has a fixed pulley piece and a movable pulley piece supported on the fixed pulley piece so that the movable pulley piece can be moved toward and away from the fixed pulley piece, the width of a groove between the pieces being increased or decreased by changing hydraulic pressure so that the rotational radius of a belt looped around the pulleys is increased or decreased to vary a belt ratio. A clutch pressure control device includes a hydraulic clutch for which engagement and disengagement is controlled according to various control modes, and a control arrangement which calculates a target clutch pressure with reference to a slip amount of the hydraulic clutch and which feedback controls the target clutch pressure so that the slip amount of the clutch is maintained substantially constant.

Abstract: A method of controlling a clutch of a continuously variable transmission system which controls a transmission system by either expanding or contracting the width of a channel between a stationary pulley member and an axially movable pulley member to expand or contract the radius of rotation of a belt wound on the pulleys to eventually vary the belt ratio. The continuously variable transmission system includes a controller unit which executes a control operation by feeding actually detected clutch pressure back to an objective clutch pressure, and an oil-pressure circuit which controls oil pressure in response to signals from the controller unit.

Abstract: A continuously variable transmission includes a driving side pulley and a driven side pulley each having a fixed pulley part and having a movable pulley part supported for movement toward and away from the fixed pulley part, the width of a groove between the pulley parts of each pulley being increased and decreased to increase the decrease at each pulley the rotating radius of a belt wound around both of the pulleys to change a belt ratio. A revolution controller for the transmission limits the rate of change of a target number of revolutions for an engine driving the transmission to a rate limit lower than a prescribed rate when the target number of revolutions of the engine specified by a speed change schedule map based on a throttle opening and a vehicle speed is changed during travel of the vehicle.

Abstract: A constant-speed running apparatus for a vehicle comprising a throttle-valve actuator for activating a throttle-valve opening angle of a vehicle engine, a constant-speed running controller for controlling the throttle-speed running, a continuously variable transmission (CVT) which is constructed in a power transmission path of the vehicle engine, and a CVT controller for controlling a transmission-ratio of the CVT; further comprising a detecting element constructed in the constant-speed running controller for a control efficiency of the constant-speed running for detecting an acceleration demand of a driver and for informing the CVT controller of the demand; and further comprising a correction element for calculating a corrected transmission-ratio as a corrected vehicle acceleration corresponding to a target vehicle accelerating force on the basis of the acceleration demand detected by the detecting element.

Abstract: A hydraulic control method is applied to a continuously variable speed change gear mechanism including a pulley having a fixed pulley member fixed to a rotary shaft and a movable pulley member movable by oil pressure toward and away from the fixed pulley member so that a groove width between the fixed and movable pulley members is decreased or increased to thereby reduce or increase the effective rotational radius of a belt extending between the pulley members and thus change a change gear ratio and control the gear change.

Abstract: A hydraulic control method is applied to a continuously variable speed change gear mechanism including a pulley having a fixed pulley member fixed to a rotary shaft and a movable pulley member movable by oil pressure toward and away from the fixed pulley member so that a groove width between the fixed and movable pulley members is decreased or increased to thereby reduce or increase the effective rotational radius of a belt extending between the pulley members and thus change a change gear ratio and control the gear change.

Abstract: A method and apparatus for controlling line pressure of a belt-type continuously variable transmission system. The apparatus controls line pressure by raising it by a specific amount in the presence of predetermined conditions when slipping of a clutch is detected during the drive mode of the system so that optimum clutch engagement can eventually be implemented.

Abstract: A novel method of controlling a continuously variable transmission system by executing sequential steps including delivering a throttle-aperture detection signal and a vehicle-speed detection signal to a controller unit; determining an optimum objective number of engine revolution in reference to a first objective number of engine revolution set by the throttle-aperture detection signal and a second-objective number of engine revolution set by the vehicle-speed detection signal and in accordance with an instruction limiting the number of engine revolution at the shift position; and executing control of the transmission system in response to the vehicle-speed detection signal.

Abstract: A method of controlling clutch pressure in a continuously variable transmission system which can expand and contract the width of a channel between a stationary pulley member and a movable pulley member movable relative to the stationary pulley member in order to respectively contract and expand a radius of travel about the pulleys of a belt engaging the pulleys before eventually varying a belt ratio, a clutch-pressure control arrangement of the continuously variable transmission system including a controller unit which effects control by feeding an actually-detected clutch pressure back in determining an objective clutch pressure and including an oil-pressure circuit which controls oil pressure in response to signals from the controller unit; the method comprising the step of: causing the controller unit to calculate a clutch duty ratio in reference to the objective clutch pressure and an objective line pressure when a pressure sensor detecting the actually-detected clutch pressure outputs an abnormal signal

Abstract: A control apparatus for controlling the gear engaged by an automatic transmission of a motor vehicle, whereby gear change operations are temporarily inhibited when a signal indicative of a fault condition in a load signal or a speed signal is sensed. The signals representing the speed and load of the vehicle are ordinarily employed directly to determine the gear engaged by the transmission. If a fault condition, such as may be due to a short circuit or open circuit of the corresponding sensor, is detected, to prevent skidding due to a sudden change to an incorrect gear, the gear presently engaged is held for a predetermined period of time. After that predetermined period of time, if the fault condition still exists, the transmission is shifted to the safest gear. Otherwise, the present gear is maintained.

Abstract: A speed change control unit of an automatic transmission for automobiles including a hydraulic servo for achieving speed change operations electrically and hydraulically controlled depending upon the operating state of an engine. The flow rate of working oil for the servo having a substantially constant pressure applied thereto and flowing through an orifice is detected so as to control the operating speed of the hydraulic servo in accordance with the flow rate, whereby changes in the characteristics of the hydraulic servo ascribable to the temperature change and quality fluctuation of the working oil of the transmission can be thereby compensated for so as to ensure a smooth speed change operation at all times.