Hydraulic circuit and manifold with multifunction valve

Abstract

A hydraulic manifold has features adapted to the needs of hybrid vehicle applications. In one embodiment, multifunction valves selectively regulate fluid flow among primary and auxiliary flow paths. A normally closed butterfly valve is biased by a relatively small secondary biasing force against rotation in first and second (opposite) directions, and by a relatively large principal biasing force against rotation in the first direction past a transitional angular position at which the principal biasing force takes effect. An actuator selectively controls the transitional angular position and the magnitude of the principal biasing force. In the first direction, flow must overcome only the secondary biasing force to pass the valve. In the second direction, any flow sufficient to overcome the secondary biasing force but not the principal biasing force will divide into a first flow passing the valve and a second flow induced to enter an auxiliary path upstream. Additional flow causing the principal biasing force to additionally be overcome will substantially pass the valve as part of the first flow. This and other embodiments provide a manifold that is controllable to allocate flow among primary and auxiliary paths while remaining responsive to sudden large changes in flow independently of immediate control response.