Technical Paper
Air-Forced Fuel Injection System for 2-Stroke D.I. Gasoline Engine
1991-02-01
910664
Late fuel injection directly into the cylinder of a 2-stroke engine is desirable to prevent escape of some fuel into exhaust system during cylinder scavenging. This leaves little time for fuel evaporation and mixture preparation and puts a premium on the degree of fuel atomization needed during the injection process. Although a respectable degree of atomization can be attained in fuel systems with high pressure, liquid-only injection, further improvements can be made when compressed air is used to assist atomization. A novel air-forced (AFI) fuel injection system for in-cylinder injection in a 2-stroke engine is described. The system employs compressed air to force a metered quantity of fuel from the fuel injector internal cavity past a spring loaded poppet valve. A fog-like cloud containing a rich mixture of fuel and air is injected into the cylinder. As a result, an exceptionally fine atomization is achieved.