Cam advancing and retarding mechanism

摘要

An engine accessory retards or advances one or more cam shafts of an engine relative to the crankshaft during engine operation. The accessory acts upon the timing chain that engages wheels on cam shafts and crankshaft. The accessory includes a rod translatably mounted to the engine, wherein a hydraulic cylinder or an electric motor translates the rod in accordance with signals from an electronic controller. The signals from the controller are in response to values of selected variables related to engine condition or are in response to manual input. Chain engagement wheels are journalled on either end of the rod. One chain engagement wheel mates with the part of the timing chain approaching the crankshaft wheel. The other chain engagement wheel mates with the part the chain travelling away from the crankshaft wheel. Translation of the rod affects the chain length between the crankshaft wheel and the camshaft wheels which are driven by the crankshaft wheel, whereby the rod's translation retards or advances the cam shafts relative to the crankshaft.