Patent ID: 6269783
Filing Date: 2001-08-07
Classification: F02B

Abstract:
A free piston internal combustion engine, comprising:a housing including a combustion cylinder and a hydraulic cylinder;a piston including a piston head reciprocally disposed within said combustion cylinder and movable during a compression stroke to a top dead center position and during a return stroke to a bottom dead center position, a plunger head reciprocally disposed within said hydraulic cylinder, and a plunger rod interconnecting said piston head with said plunger head, said plunger head and said hydraulic cylinder defining a variable volume pressure chamber on a side of said plunger head generally opposite said plunger rod;a high pressure hydraulic accumulator with a high pressure fluid therein;at least one valve interconnecting said high pressure hydraulic accumulator with said pressure chamber during a beginning portion of said compression stroke to provide a pulse of said high pressure fluid to said pressure chamber and thereby move said piston head toward said top dead center position;a low pressure hydraulic accumulator with a lower pressure fluid therein; anda valve interconnecting said low pressure hydraulic accumulator with said pressure chamber during a remaining portion of said compression stroke to allow a lower pressure fluid to flow into said pressure chamber.