Scavenging Performance Measurements of High Speed Two-Stroke Engines

In order to improve the performance of two-stroke engines for motorcycles, it is necessary to measure the trapping efficiency at engine speeds up to 8, 000 rpm. The Watson method is usually used to determine the trapping efficiency by measuring the oxygen concentration in the exhaust gas. However, up to now this method had never been applied at such high engine speeds.

In the paper, engine performance is found to be evaluated completely according to the charging efficiency, which is based upon the trapping efficiency measured appropriately. Moreover, a technique for estimating the scavenging efficiency is described.