High Performance Characteristics of a Motorcycle Powered by a Four-Stroke Small 50cc-125cc Engine at the Expense of a Positive Displacement Air Compressor as a Supercharger

摘要

There are several problems with small motorcycle (moped, scooter) engines of 50cc-125cc displacement, and even up to 200cc for special applications. Lack of engine power and design complexity of a multi-valve cylinder head are the most important problems. Despite some isolated attempts and several patented works the small engines of 50cc to 350cc displacement undeservedly remain without adequate air charging means - neither superchargers nor turbochargers are offered to the market. This article presents a theoretical basis on how to improve high performance characteristics of a motorbike by supplying a working cylinder with additional compressed air under certain conditions. A few versions of a positive displacement air compressor (supercharger) have been developed, built, and used for engine boosting. Road tests of the pitbike motorcycle equipped with our small rotor-vane compressor were performed. The results exceed expectations of the supercharger's performance and efficiency. Thus, to reach 50 km/h for the motorcycle powered by the 50cc four-stroke engine equipped with the supercharger, 40% less time is needed than for the same motorcycle powered by a naturally aspirated engine.