A Fresh Approach to the Design of Clean Engines for the Performance Motorcycle Market

Until the early to mid 1990's the engine of choice for off road and recreational vehicles were mainly 2-stroke engines due to the superior power density and Wide Open Throttle (WOT) torque characteristics. With the introduction of increasingly more stringent emission control requirements there has been a large swing to 4-stroke engines. In recent years there has been significant development to improve the power density of the 4-stroke engine in an effort to match the performance 2-stroke engine, however at a compromise to the torque characteristics and the manufacturing and maintenance cost of the engine. This paper looks at a fresh approach to develop a new concept engine to deliver a better compromise between the 4-stroke and existing carburettor 2-stroke characteristics, and provides early experimental results from the development work for a preferred WOT torque characteristic.