Patent ID: 8104436

Claim:
A quasi free piston internal combustion engine, comprising: a pair of axially opposed combustion cylinders; a pair of combustion pistons respectively mounted in said combustion cylinders for reciprocating linear motion therein, responsive to successive combustion events within said combustion cylinders; a rigid means connecting said pair of combustion pistons to form a reciprocating dual piston assembly which reciprocates as a single unit; pumping pistons driven by the linear motion of the combustion pistons; a pair of axially aligned hydraulic cylinders respectively receiving said pumping pistons for reciprocating linear motion therein; ports in each of said hydraulic cylinders for admitting fluid at a first pressure and discharging fluid at a second pressure higher than the first pressure; a crankshaft mechanically connected to the dual piston assembly through a connecting rod; and a flywheel rotationally driven by the crankshaft.