Development of a Three Wheeler Engine With LPG fuel For Improved Performance Using Simulation Techniques

Three-wheeler is a popular mode of transport in developing nations. Customers demand higher fuel economy from the vehicles to keep the operating costs to a minimum. Competitive environment of automobile market demands for new improved products with minimum development time. Computer simulations are very useful in reducing the development time through virtual prototyping and testing the system on computers rather than making the physical prototypes and testing on road. Particularly, lumped parameter modeling provides reasonably accurate results for predicting vehicle performance characteristics in short span of time. This is very useful when various system level targets have to be achieved and when trade-offs have to be made to obtain optimal results. This paper focuses on the development of a three-wheeler with LPG fuelled engine to achieve target performance using simulation tools. Performance levels of LPG powered vehicles are not optimum when the parameters of gasoline engines are followed as it is. The engine and vehicle performance simulation tools are used along with Design of Experiments (DoE) to achieve the target performance levels for an LPG engine, at all throttle and engine speed conditions. The major engine specifications required for LPG fuel are arrived from the engine parameter optimization using the 1-D thermodynamic software. The effect of variables such as compression ratio, valve timing, ignition timing, exhaust pipe and intake pipe parameters is evaluated. Predicted engine performance data is used to simulate the overall vehicle characteristics e.g., acceleration and tractive force, to compare against the base gasoline vehicle performance. The work is further extended to optimize driveline parameters to achieve improved fuel economy.