Technical Paper
SCIP : a New Simplified Camless IAPAC Direct Injection for Low Emission Small Two-Stroke Engines
1997-10-27
978455
The IAPAC Direct fuel Injection (DI) system, developed by IFP, has already well proven its capability to reduce pollutants emissions and fuel consumption of 2-stroke engine. This crankcase Compressed Air Assisted Fuel Injection Process allowing the introduction of the fuel separately from the scavenging air, minimizes the fuel short-circuiting. In earlier works, results of the implementation of the IAPAC system on cylinder displacement from 125 cc to 400 cc have been presented in various papers. These first prototypes were all using a camshaft to drive the IAPAC DI poppet valve, which was considered as a limitation for applying this system to small displacement 2-stroke engines. The new SCIP system is no more using a camshaft. The IAPAC poppet valve used for low pressure air assisted fuel atomization and in-cylinder injection, is here actuated by a diaphragm and the lift of the valve is controlled by pressures from the engine.