A Model Method for the Evaluation of the Scavenging System in a Two-Stroke Engine

Due to inadequate scavenging process two-stroke petrol engines suffer from substantial specific consumption as well as from poor emission of the toxical components in the exhaust gasses. The paper describes two different scavenging systems: the conventional-so called single phase (Schnürle) one, and the second most sophisticated two phase scavenging system. The effectiveness of the two systems was defined by means of the qualitative scavenging efficiency factor and the model methode was applied for this purpose. Instead of gasseous liquid working media were used on the model engine. A mathematical model based on the principles of the approximate similarity was also developed. It makes us possible to establish the relationships between the most important parameters on the model engine and on the real engine. A special testing device makes us possible the quantitative evaluation of the predictet values and the simulation of the working medium exchange process at different working conditions.