External speed–torque characteristics of Fiat 0.9 TwinAir petroland CNG-fuelled engine

The paper presents the results of the experimental study of the turbocharged spark ignition Fiat 0.9 TwinAir engine, with indirect, multipoint petrol injection system, powered by petrol and equipped with the injection system of the compressed natural gas (CNG) supplying gas into the intake manifold. The test results provide the comparison of the selected fuel-efficiency, energetic and ecologic indicators of engine work, obtained when it is powered by Pb95 petrol and the CNG gas. The paper compares the external torque-speed characteristics with factory-set engine controllers. Also presented are the concentration levels of harmful gases in the exhaust fumes: carbon monoxide (CO), nitric oxides (NO_x), hydrocarbons (HC) and carbon dioxide (CO₂). Results obtained on the engine powered by CNG are indicating lower power and torque, lower concentration of hazardous gases, in particular carbon monoxide and hydrocarbons as well as significantly lower consumption of the gas when compared to petrol.