Abstract: A control system for controlling hydraulic pressure in a dual pass continuously variable transmission includes a pump to provide primary and secondary hydraulic pressures for regulating the pulley ratio and belt tension. A minicomputer regulates the primary and secondary pressures, and a transition mechanism alternates the paths of the primary and secondary pressures between first and second pulleys of the transmission so that the primary pressure is fed to the drive pulley and the secondary pressure is fed to the driven pulley.

Abstract: A continuously variable transmission system having a controllable variable speed component and a fluid controlled clutch includes a schedule for providing a desired engine speed in response to the engine throttle angle and engine torque, and a system element for providing an error signal representative of the difference between desired and actual engine speeds. The error signal is developed to provide an output signal representative of a required clutch pressure that allows clutch slippage sufficient to unload the engine and allow it to rapidly reach its desired speed. The clutch is reengaged when the engine speed and the ratio of the variable speed component have reached or approached their required values.

Abstract: A power train configuration for a continuously variable transmission includes a slippable start clutch located upstream of a belt and sheave system and a pair of non-dynamic forward-reverse clutches located down stream of the continuously variable component. The clutch capacities of the pair of forward-reverse clutches are marginally greater than the maximum torque capacity of the engine but marginally less than the torque at which the belt of the belt and sheave system slips.

Abstract: A solenoid operated hydraulic control valve which has a specially ported spool valve to statically balance spool force in the opened and closed positions, and a specially designed solenoid operator which includes very small ratios of gaps to cross-sectional areas for the working and non-working gaps between the armature and stator.

Abstract: A pressure transducer, which senses clutch pressure and effects closed loop clutch control in a continuously variable transmission, is used after the clutch is fully engaged to provide closed loop line pressure control to a desired setpoint, which line pressure regulates the tension on the belt in the transmission. Only a single transducer is needed since there is a known relationship between the clutch and line pressures when the clutch is locked up. Prior to lockup, the line pressure is governed by an open loop controller which establishes the line pressure at a level higher than that called for by the setpoint. This ensures that the line pressure will be high enough to provide the required tension on the belt so that it will not slip. After the clutch is engaged, the closed loop line pressure controller (which includes both the open loop line pressure controller and the closed loop clutch controller) establishes the line pressure at the setpoint.

Abstract: An electromechanical valve apparatus has an electrical winding and a magnetic flux circuit defining a flux path therefor which includes a plurality of adjacent magnetic segments. The segments include a generally cylindrical center segment with a fluid passage, an end segment, an outer segment and a magnetic armature member. At least one of the segments is physically translatable within the valve apparatus along the flux path to adjust a portion of one of the magnetic segments that is in the flux path and the extent of an air gap adjacent the translatable segment. The apparatus includes a non-magnetic seat member which is located near or at the point of highest flux density along the longitudinal axis through the electrical winding. The armature is preferably an elongated cup member with its closed end located within the electrical winding near the non-magnetic seat member. The seat member and armature are enclosed within a chamber defining body such as the bobbin.

Abstract: This invention relates to a unique transmission system for applying torque from an engine flywheel to the drive train of an automotive vehicle including a long travel viscous damped torsional damper driven by the flywheel and coupled to a continuously variable transmission which in turn is coupled to a wet drive clutch, the output of which is connected to an output counter shaft for the automotive drive train. An important part of the unique combination is the long travel viscous damped torsional damper of the invention which includes an enclosed, effectively sealed housing contains input and output members coupled through a plurality of series parallel spring sets and immersed in a viscous medium to provide effective viscous damping matched to the effective spring rate of the mechanical damping system to accommodate both transient and steady-state vibrational torques. The damper is especially useful with the continuously variable transmission but is useful in other applications as well.