The Environmental Safety of the Fiat 0.9 TwinAir Compressed Natural Gas Engine

Abstract

The article presents the results of measurements of concentrations of selected exhaust components of the Fiat 0.9 TwinAir spark-ignition engine operating according to load characteristics. The tested engine has an indirect, multi-point petrol supply system and has been retrofitted with an indirect CNG injection system. The results of the tests are a comparison of selected economic, ecological and energetic indicators of engine operation obtained when fuelled with CNG and 95 octane petrol. The operation of the engine fuelled with gaseous fuel was preceded by autocalibration of the controller of the fuelling system. The article presents the results of tests of concentrations of harmful components of exhaust gases: carbon dioxide CO2, carbon monoxide CO, nitrogen oxides NOx and HC hydrocarbons. Moreover, the values of lambda λ air excess coefficient are presented and fuel consumption is compared. The obtained results of the tests of the engine fuelled with CNG gas show a significant decrease in the value of the obtained torque in comparison to the engine torque when fuelled with petrol. The engine fuelled with compressed natural gas contributed to the improvement of its ecological properties and a reduction of fuel consumption, which are important factors of ecological and energy safety. Exhaust gas analysis showed a reduction in the concentration of harmful components of exhaust gases, mainly hydrocarbons and nitrogen oxides. A positive effect of the operation of the engine powered by CNG was also a significant reduction of carbon dioxide in the exhaust gases compared to the engine powered with gasoline.