Two-stroke cycle, free piston, shaft power engine

Abstract

A simple two-stroke cycle engine can match the four-stroke cycle engine in efficiency and low exhaust emissions by incorporating a spring powered free-piston reciprocating within a sleeve valve to provide the required separation of gases during the exhaust and intake functions. The exhaust gas is displaced by the free-pistons' top surface, while simultaneously the bottom surface creates suction for the intake process during its upward stroke. These processes are completed in the interval between the effective end of the power stroke and the effective beginning of the compression stroke. The sleeve-valve controlled exhaust and intake ports of the cylinder are at the top and bottom extremities of the free-pistons' travel, respectively. The spring-powered travel of the free-piston to the top of the cylinder starts with the release by “blow-down” of the restraining combustion pressure at the start of opening of the exhaust ports. The continuously moving crankshaft mounted sleeve valve (having a bulkhead closure in-line with the bottom edge of its intake ports) following its upward stroke closing of the intake and exhaust ports, begins compression of both the previously inducted gas charge and the spring against the bottom of the free-piston now stationary against the cylinder head. Through the check valve in the free-piston, the charge is pumped into the combustion chamber with increasing pressure to be ignited by a spark at nearly the top center position of the sleeve valve/bulkhead assembly. Upon combustion, the spring biased free-piston abuts the bulkhead, and in this nested form, the assembly proceeds on its power stroke.

Dependencies are inferred from the claim text.