Two stroke direct injection spark ignition engine for two wheelers

Two stoke engine for mopeds and motorcycles is reaching an important appointment for its survival. In fact, already with the introduction of EURO 1 emission limits, it was necessary to modify some components of the propulsion apparatus in order to reduce especially the huge amount of HC emissions, due to the mixture losses during the scavenging. It was demonstrated that an effective solution to lessen emissions, including benzene, from current two stroke engines for two wheelers, could be retrofitting circulating vehicles with a catalyst. But this is not enough to comply the future more stringent European limits. A powerful solution has been suggested by an important Italian two wheeler manufactures based on the direct injection of gasoline, during the compression stroke, when the exhaust port is closed. The engine is described in the paper, in terms of performance and emissions, and the main results are reported.