Direct Fuel Injection: Piaggio Approach to Small 2T SI Engines

Following general considerations about the advantages of two stroke S.I. engines equipped with direct fuel injection systems, especially for light vehicle applications, two solutions, developed for mass production, are presented.

The first one deals with a mechanical high pressure D.I. system characterized by an essential fuel delivery control.

The second one is concerned with an electronic low pressure semi - D.I. in view of a reduction of the involved costs.

While the mechanical solution achieves a dramatic reduction in HC emission and fuel consumption but with high costs, the electronic one still appears a good compromise between improvements and costs when very fast injectors are industrially available.