Abstract: A method of controlling a power transmitting system for an automotive vehicle, having a continuously variable transmission and an auxiliary transmission which is connected with the continuously variable transmission, and which has at least two shift positions for forward driving of the vehicle. The auxiliary transmission is automatically shifted from one of the shift positions to another, based on a detected speed, a detected currently required output of the vehicle, and a detected speed ratio of the continuously variable transmission. Alternatively, the auxiliary transmission is shifted from one of the shift positions to another in response to an operation of a manual shift lever. When a predetermined condition is satisfied after the shift lever is operated to a given position, the auxiliary transmission is permitted to be shifted to the shift position corresponding to the position of the shift lever.

Abstract: A continuously variable transmission (CVT) has input and output pulleys interconnected by a V-belt. The output pulley is actuated by a line pressure. A throttle pressure is increased as the position of an intake throttle valve arranged in an intake path is increased. A transmission-ratio pressure is decreased as the position of the intake throttle valve is increased. The transmission-ratio pressure is decreased in the region of smaller openings of the intake throttle valve more gently than in the region of larger ones. The line pressure is produced in relation to the throttle pressure and the transmission-ratio pressure.

Abstract: A method for controlling a continuously variable transmission installed in an engine. The method controls the continuously variable transmission so that the actual maximum speed ratio of the continuously variable transmission may be set to be lower than the maximum speed ratio within the range where the speed ratio can be controlled.

Abstract: A hydraulic control system for a continuously variable transmission having a cylinder for changing the effective diameter of a pulley to control a speed ratio of the transmission. The control system comprises a spool valve assembly communicating with the cylinder to control the supply and discharge flows of a fluid to and from the cylinder. The valve assembly comprises a shift-speed control valve unit for controlling a rate of variation in the speed ratio of the transmission. The shift-speed control valve unit has only two discharge ports associated with the fluid discharge from the cylinder. The shift-speed control valve unit may take the form of a spool valve having a spool axially movable to open and close the ports to permit and restrict the fluid flows through supply and discharge conduits communicating with the ports and the cylinder. The spool may only partially open the corresponding port to permit the fluid flow therethrough for supplying or discharging the fluid.

Abstract: A method for controlling a continuously variable transmission installed in a vehicle. The method controls the continuously variable transmission such that the desired engine speed or the desired transmitting speed ratio of the transmission may be determined to be a function of a throttle opening or a pressure within an intake pipe and a vehicle speed.

Abstract: System and method for controlling a continuously variable transmission having a pair of variable-diameter pulleys disposed on input and output shafts, and a corresponding pair of hydraulic cylinders to change effective diameters of the pulleys. A speed ratio control valve assembly is used to control flows of a fluid to and from one of the cylinders. The control valve assembly is selectively placed in one of three states consisting of a first state for feeding the fluid to the one cylinder, a second state for discharging the fluid from the one cylinder, and a third state for restricting the flow to or from the one cylinder.

Abstract: An apparatus for controlling an continuously variable transmission (CVT) used for a power transmission system of a vehicle. The CVT is controlled such that an actual engine speed becomes a desired engine speed. The desired engine speed is set as a function of running parameter such as intake throttle position. When the CVT is controlled in the same way as at the steady state of the vehicle at the acceleration of the vehicle, the acceleration performance is degraded. Thus, according to the present invention, the speed ratio of the CVT is reduced when the acceleration of the vehicle is small, in spite of the requisition of the vehicle acceleration. As a result, satisfactory drivability is attained.

Abstract: A method is provided for controlling an engine using a continuously variable transmission whereby the fuel consumption of the engine is decreased. When an accelerator of the engine is displaced, first and second desired engine speeds are determined for steady state conditions before and after the displacement of the accelerator, respectively. The difference between the two desired engine speeds is calculated and compared with a predetermined value. If the difference between the desired engine speeds is smaller than the predetermined value, the actual engine speed is adjusted to gradually approach the second desired engine speed. If the difference between the two desired engine speeds is larger than the predetermined value, the actual engine speed is immediately adjusted to a transient value and is then adjusted to approach the new desired engine speed gradually.

Abstract: A method for controlling an engine using a continuously variable transmission, the method decreases the fuel consumption of the engine in a transient shifting condition. When the operator displaces the accelerator means and the magnitude of the difference between a steady state engine speed, which corresponds to the amount the throttle means of the engine is opened, and a previously detected engine speed differs from a predetermined constant value, the engine speed abruptly increases after a predetermined time elapses and thereafter the engine speed gradually changes to the steady state engine speed. The abrupt increases in the engine speed is a function of a vehicle speed and the amount of the throttle opening.