Development and Evaluation of a Multipoint Gas Injection System for a Passenger Car

An electronically controlled sequential gas injection system was developed and tested for a 4 cylinder passenger car spark ignition engines. The vehicle is bi-fuelled i.e. it can run with gasoline and CNG fuel based on the need and availability of the fuel. The fuel mode can be selected with a selector switch. The master slave concept was adopted, in this concept output of the gasoline ECU is the input for the gas ECU. Different parameters like injection duration and ignition timing were optimised under idling and different load conditions. The change over performance from gas to petrol and petrol to gas were also analysed. Start-ability, idle stability were also analysed. The effect of gas injection pressure on pulse width and engine stability are also analysed and discussed. After calibration and optimisation vehicle was tested for performance and mass emissions. Test results indicate CO2 emissions are reduced by 25%, CO and HC were comparable and power is reduced by 12 percent in CNG mode as compared to gasoline mode with Gas injection system. Gas injection system meets the BS3 emission with comfortable margins and can be calibrated for BS4.