From Development to Industrialization of an IAPAC® Marine Outboard D.I. 2-Stroke Engine 2001-01-1780

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 for both 2-wheeler and marine outboard application. This crankcase Compressed Air Assisted Fuel Injection process allowing the introduction of the fuel separately from the scavenging air, minimizes the fuel short-circuiting and has shown its potential on various prototype demonstrators.

This paper presents the development and pre-industrialization work performed to apply this concept to an SELVA Marine 2-cylinder 50 HP outboard 2-stroke engine. A standard carbureted engine has been converted to a IAPAC® prototype engine by mainly modifying the cylinder head. Then, this prototype engine has been calibrated, tested and optimized on the dyno test bench to comply with future emissions regulation while keeping similar power output than the reference carbureted engine. Transient operations, partially investigated on the dyno test bench, have been refined during the boat testing campaign.

After this feasibility assessment study which has demonstrated more than 30% reduction in fuel consumption and the capability to comply with both IMEC Stage 2 and EPA 2006 emission regulations with sufficient margin, the pre-industrialization phase has been engaged by taking into account a better integration of the specific IAPAC® components.

Final results of this IAPAC® pre-industrial D.I. 2-stroke engine are presented and also compared to its other engine counterpart technology showing its adequate application to face future stringent emissions regulations and environmental constraints while keeping its intrinsic advantages in terms of compactness, light weight and specific power.