Exhaust emissions and fuel consumption of a triple-fuel spark-ignition engine powered passenger car

This paper examines the influence of compressed natural gas, liquefied petroleum gas and gasoline fuel on the exhaust emissions and the fuel consumption of a spark-ignition engine powered passenger car. The vehicle was driven according to the urban driving cycle and extra urban driving cycle speed profiles with the warmed-up engine. Cause and effect based analysis reveals potential for using different fuels to reduce vehicle emission and deficiencies associated with particular fuels. The highest tank to wheel efficiency and the lowest CO2 emission are observed with the natural gas fuelled vehicle, that also featured the highest total hydrocarbon emissions and high NOx emissions because of fast three way catalytic converter aging due the use of the compressed natural gas. Retrofitted liquefied petroleum gas fuel supply systems feature the greatest air–fuel ratio variations that result in the lowest TtW efficiency and in the highest NOx emissions of the liquefied gas fuelled vehicle.

► Influence of utilizing CNG, gasoline and LPG fuel on variation in fuel consumption.
► Benefits and deficiencies of different fuels with regard on vehicle emissions.
► CNG fuel features the highest TtW efficiency and high THC and NOx emissions.
► Large A/F ratio variations of the retrofitted LPG fuel delivery system.