CONTROL VALVE SYSTEM FOR A FOUR SPEED RATIO AUTOMATIC TRANSMISSION INCLUDING A DUAL RANGE REGULATOR VALVE FOR CONTROLLING INDEPENDENTLY TWO UPSHIFT RATIO CHANGES

摘要

A control system for a four speed ratio automatic transmission wherein a ratio change from a first speed ratio to a second speed ratio is effected by a 1-2 shift valve that activates a fluid pressure operated second ratio clutch and a ratio change from a third speed ratio to a fourth speed ratio is effected by a 3-4 shift valve that activates a fluid pressure operated fourth ratio brake, both the clutch and the brake having an independent pressure accumulator and an accumulator pressure regulator valve that is common to both accumulators for developing unique accumulator control pressures whereby the system may be calibrated for maximum shift smoothness for both 1-2 upshifts and 3-4 upshifts.