Application of Low Pressure Direct Injection and Semi-Direct Injection to a Small Capacity Two-Stroke Engine

Based on the fundamental analysis of the two-stroke process (SETC 2005-32-0098) and the development of a stratified scavenged small capacity two-stroke engine (SETC 2006-32-0065), a further approach to achieve low emissions in this engine category is the main subject of this publication.

The principles of the system are described by design activities, results of the 3D-CFD simulation and the visualization of the spray in the cylinder. The benefit of this system on exhaust emissions is demonstrated by engine test bench as well as chassis dynamometer results. The achievable reduction of exhaust emissions, especially with an applied oxidation catalytic converter, is remarkable and the potential to fulfill future emission limits has already been demonstrated.

Additionally, the system, which will be available early 2009 on the market, is compared with alternative low emission 50 cm³ concepts, like the ASDI system and a four-stroke closed loop system in order to demonstrate its potential for the future.