Abstract:
Pre-evaporated Stratified Injection (PSI) is a low-cost
mechanical fuel injection system which dramatically
reduces exhaust gas emissions in small IC engines. In
two-stroke engines, this is achieved by incorporating a
mechanically driven coaxial air-fuel injector within the
upper half of an engine's main piston. In four stroke
engines the injector cylinder is located in the cylinder
head with the injector piston driven by the valve cam. In
both configurations, the relative motion of the injector
piston draws a rich air-fuel mixture from the carburetor,
captures and compresses for sufficient time under most
operating conditions to SUbstantially evaporate fuel
before direct injection into the cylinder.
This technology allows for stratified charge combustion
without wall wetting (spray impingement), leading to
lower hydrocarbon (HC) and carbon monoxide (CO)
emissions in four-stroke engines, and for the first time
allowing low cost, small two-stroke engines to meet nonhandheld
emission standards.
