Hydraulic drive for cam setting in IC engine - has hydraulic pump driven by reversible DC motor and separated from pump by non return valves cross linked to other feed lines.

摘要

The relative setting of the cam and the camshaft for each cylinder, is controlled by a hydraulic servo cylinder (15) connected to both sides of a constant output hydraulic pump (10). The pump is driven by a reversible DC motor (11) and the servo is separated from the pump by non return valves (26, 28). The motor is a permanent magnet DC motor. The non return valves are cross linked to the other feed lines for pressure control and for return feed of fluid. A control valve (35) controls the return flow to the sump (38) as well as the pump take-up from the sump. ADVANTAGE - Power saving pump only operated when required. Variable cam setting control. Reduced power loss, so reduced exhaust emissions.