Patent ID: 7827943
Filing Date: 2010-11-09
Classification: F02B,F02D

Abstract:
1. A variable compression ratio system for use in a reciprocating-piston engine having a combustion cylinder and a crankshaft, the variable compression ratio system comprising: a hydraulically operated variable length mechanism having: a source for supplying pressurized hydraulic fluid having an injection check valve permitting flow of hydraulic fluid from the source and blocking flow in the opposite direction; a sink for receiving pressurized hydraulic fluid having a pressure control valve for providing a variable degree of resistance to the flow of hydraulic fluid to the sink responsive to a control signal; a slave hydraulic pump for alternatively supplying and withdrawing hydraulic fluid to and from the variable length mechanism having: a control unit for providing the control signal, wherein a degree of resistance provided by the pressure control valve, responsive to the control signal, is in accordance with a desired compression ratio; wherein the degree of resistance provided by the pressure control valve creates a backpressure in the slave hydraulic pump, the equalization of the hydraulic pressures in the slave hydraulic pump and the hydraulic cylinder resulting in alternatively the supply and withdrawal of hydraulic fluid to and from the hydraulic cylinder response to a pressure differential, the distance from the combustion-chamber facing surface of the engine piston to the center of the pivotal connection of the connection rod to the crankshaft alternatively increasing and decreasing responsive to the volume of hydraulic fluid alternatively supplied and withdrawn from the hydraulic cylinder, and the compression ratio of the engine increasing when the distance is increased and the compression ratio decreasing when the distance is decreased.