Development and Testing of a Novel Direct Mixture Injection System for a Two Stroke SI Engine



Small Engine Technology Conference & Exposition
Authors Abstract
In this work a novel mixture injection system has been developed and tested on a two stroke scooter engine. This system admits finely atomized gasoline directly into the combustion chamber. It employs many components that were individually developed, fabricated, tested and then coupled together. A small compressor driven by the engine sends pressurized air at the correct crank angle through a timing valve. This is connected to a mechanical injector through a high pressure pipe. Fuel is metered into the high pressure pipe using a standard low pressure injector. The developed mixture injection system resulted in considerable improvements in thermal efficiency and reduction in HC emissions over the manifold injection method at all engine outputs. A considerable reduction in short circuiting losses was seen. The highest brake thermal efficiency achieved was 25.5% as against 23% with the manifold injection system. The minimum HC level is 460 ppm where as for manifold injection it is 1360 ppm. Better combustion with the developed system lead to a small increase in the peak NO level as compared to the manifold injection system. Further improvements are possible by redesigning the compressor and combustion chamber.
Meta TagsDetails
Loganathan, M., and Ramesh, A., "Development and Testing of a Novel Direct Mixture Injection System for a Two Stroke SI Engine," SAE Technical Paper 2008-32-0077, 2008,
Additional Details
Sep 9, 2008
Product Code
Content Type
Technical Paper