Abstract: A hydraulic valve assembly is provided to activate and deactivate cylinder valves of a multi-cylinder engine. A plurality of electrohydraulic valves are loosely received in openings in a base plate which allows the relative positions of the valve to adjust automatically for dimensional irregularities as the assembly is installed on the engine. At the complete of that installation, elements of each electrohydraulic valve are clamped between the base plate and the engine to secure the valves in position. A flexible lead frame containing electrical conductors is secured to both the base plate and the electrohydraulic valves provides additional support while allowing movement of the valves with respect to the base plate.

Abstract: An electrically operated valve controls the flow of oil to and from a device that activates and deactivates a cylinder of a multi-cylinder engine. A first valve seat is between an inlet and a workport connected to the device and a second valve seat is between the workport and an outlet. A valve element engages the first valve seat when a solenoid actuator is energized. The valve element and the first valve seat cooperate to allow air to bleed from the inlet through the valve upon starting the engine, but prevent the oil from flowing in that path unless the solenoid actuator is energized. In one version of the valve, the valve element engages the second valve seat when disengaged from the first valve seat. In a second version, another valve element engages the second valve seat when oil flows through the first valve seat.

Abstract: An improved pressure-compensated hydraulic system for feeding hydraulic fluid to one or more hydraulic actuators. A remotely located, variable displacement pump provides an output pressure equal to a control input pressure plus a constant margin. A pressure compensation system requires that a load-dependent pressure be provided to the pump input through a load sense circuit. An isolator transmits the load-dependent pressure to the pump control input, while preventing fluid from leaving the load sense circuit and flowing to the remotely located pump. A valve section, which controls the fluid flow between the pump and actuator, has a pressure compensating valve with a piston and spool controlling a pressure differential across a main control valve orifice by moving within a bore in response to a pressure differential between a pump supply pressure and the load sense pressure.

Abstract: An improved pressure-compensated hydraulic system for feeding hydraulic fluid to one or more hydraulic actuators. A remotely located, variable displacement pump provides an output pressure equal to input pressure plus a constant margin. A pressure compensation systems requires that a load-dependent pressure be provided to the pump input through a load sense circuit. A reciprocally spooled, multiported isolator transmits the load-dependent pressure to the pump input but prevents fluid in the load sense circuit from leaving the load sense circuit and flowing through a relatively long conduit leading to the remotely located pump. In a multi-valve array, at least one valve section has a backflow-preventing shuttle valve which prevents backflow through the pressure compensation system if a main relief valve is operative.