Experimental investigation of performance for single cylinder spark ignited cng fueled engine at different compression ratios

The petrol reserves of the world is decreasing year by year and the air pollution rate is increasing due to the industrial development. Because of that CNG is accepted as new alternative fuel and the researches about CNG fuel is increasing globally. With increasing usage of CNG and studies about cogeneration and trigeneration highly encourage scientific researches about this topic. In this study, gasoline fueled spark ignited engine with 661 cm^3 cylinder volume and adjustable compression ratio has been retrofitted and CNG started to be used as new fuel. In the new fuel line CNG was delivered at 2 bar pressure. Injection timing was determined as beginning of suction stroke and the ignition timing was determined 26 CAD. Butterfly valve was used at wide open position. It was aimed to learn either CR or CR 10 is more effective. Experiments were made at 1000, 1400 and 1800 rpm. Regarding to the experimental results it was observed that increase in break mean effective pressure is less than increase in break power while compression ratio was changed from 8 to 10. However it was seen that engine works more effectively and consumes less fuel at compression ratio 10 compared to compression ratio 8. Then the performance values of CNG operation was compared to Gasoline operation. Power, pressure and torque values of CNG operation is higher than the values of gasoline operation at high speed while there is not much difference between different operations at low speed. Fuel consumption and break thermal efficiency values are higher for CNG operation compared to gasoline at low speed while the values are higher for gasoline operation at high speed. It was seen that volumetric efficiency is lower for gasoline operation. Keywords: Alternative fuel, Natural gas engine, Engine performance