Shift control for high and low speed clutches of motorcars

Abstract

A control apparatus for motorcars having an automatic transmission with a speed-change sensor and a shift valve therein, for controlling the operation of the latter, the apparatus comprising oil-pressure operated high-speed and low-speed clutches interposed in respective high-speed and low-speed systems of the transmission, the system being selectively connectable through the shift valve to a line pressure supply passage connected to an oil-pressure source, wherein the shift valve is operable by the oil pressure and has at one end an oil-pressure chamber connectable to the supply passage through an electromagnetic pilot valve that is responsive to the sensor. Preferably a manually operable valve is interposed between the supply passage and the oil-pressure source, for selectively operating the oil-pressure controlled shift valve in one of a plurality of operational modes of the transmission.

Dependencies are inferred from the claim text.