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With the introduction of increasingly more stringent emission standards, Engine Management Systems (EMS), including port fuel injection, are now being introduced in the 4-stroke motorcycle marketplace. These systems have been generally derived from the automotive industry, albeit with some significant changes to satisfy the strict cost and packaging constraints of the motorcycle applications. Direct injection (DI) is positioned to become one of the next generation of technologies for the automotive engine, offering the potential for improved fuel economy, performance and emissions control. Direct injection can also provide similar benefits for motorcycle applications. However, direct transfer of the current production automotive systems is unlikely to suit the requirements of motorcycle applications, due to some of the specific challenges faced in the motorcycle market.

It has been shown that an automotive, stratified charge, direct injected (DI) 2-stroke engine is capable of meeting the proposed Stage 3 European emissions standards and the Ultra Low Emissions Vehicle standards of California at low mileage. In order to meet these stringent standards and develop a high in-field mileage capability for this lean burn engine, new engine control strategies and catalyst formulations have been developed. Engine out emissions and catalyst temperatures over both the proposed Stage 3 New European Drive Cycle (NEDC) and Federal Test Procedure (FTP) are described. Also with catalyst light-off time being an important factor in determining the overall cycle emissions, engine calibration based Fast Light Off and light load exhaust temperature strategies have been developed, in conjunction with optimised catalyst system configurations.