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In this work, a new mechanical cam phaser (MCP) system is developed. This MCP system is simple, reliable, and cost-effective, and also offers good control. Phasing of either intake, exhaust or both intake and exhaust cam can be achieved with this system. A prototype of the mechanical cam phaser has been tested on a motored rig to validate its dynamic characteristics. The system was tested onto a small two wheeler engine and this paper describes the newly developed MCP mechanism and its effects on the performance of a small two wheeler engine.

Engine operation at low temperatures is of considerable interest from the standpoint of exhaust gas emissions and fuel economy. A semi-empirical film model is developed to study the transient cold starting process. Variation of air-to-fuel ratio reaching the cylinder during the starting is estimated. Film-model uses some inputs from the CFD simulation and essentially avoids the multiple cycle CFD simulation. CFD simulation was carried out with unsteady boundary condition obtained from the experiment. The experiments were conducted at different temperatures inside cold chamber. Air-to-fuel ratio variations were recorded after starting which is used for qualitative comparison with the film model. The model is able to capture the qualitative trends observed in the experiment.