Browse Publications Technical Papers 1999-01-3289

SCIP Simplified Direct Injection for Low Emissions Small Two-Stroke Engines 1999-01-3289

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 engines. 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 neither driveshaft, or any electric power supply to drive the DI air assisted injection valve. The IAPAC poppet valve used for low pressure air assisted direct injection of fully atomized fuel, is here mechanically actuated by a diaphragm driven by pressures from the engine. The SCIP air assisted injector unit can be easily bolted on existing 2-stroke cylinder heads with minimum engine intrusion and redesign.
To be combined with the SCIP technology and hardware, Sagem has developed a low cost Engine Management System (EMS) including low pressure mass produced Electronic Fuel Injection (EFI) components for fuel metering. The key features of the Sagem MC 500 SCIP system are described in details. It also includes additional enhancement capabilities, such as lubrication oil control, vehicle anti-theft,…
After preliminary development and endurance testing carried out on a 125 cc 2-stroke scooter engine and described in a previous paper, the SCIP system has been applied to a 50 cc scooter engine and to a 125 cc small marine outboard for demonstration. The results obtained with these two proof of concept prototypes are described and show the SCIP capability to meet future European 2-wheeler as well as US EPA 2006 marine outboards emissions regulations while maintaining driveability and performance characteristics.
Combined with the SAGEM-developed MC 500 Engine Management System for small engines, the SCIP system appears therefore as a simple and highly efficient way to reduce pollutant emissions and fuel consumption of small 2-stroke engines.


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