Effect of Natural Gas Usage as Fuel in Gasoline- Based Vehicle Using 100% Substitution Method

Abstract

Abstract This study performed a comparative experimental analysis of vehicle performance, fueled with domestic gasoline and compressed natural gas (CNG). A passenger vehicle, with 1.5 L, 4-cylinder gasoline engine was used as tool through a road test, dyno test and idling emission measurement. The 100% substitution method was applied in all experiments. The road test covered the distance of Serpong-Bandung (Route I, 237 km) and Bandung-Jakarta (Route II, 142.4 km). In general, this study revealed that all engine performance parameters decreased by CNG usage, but CNG has advantages over gasoline, including considerable emission and cost reductions. In term of fuel economy, gasoline was more efficient by covering longer distance per liter fuel, but CNG gave almost 50% fuel cost cutting per kilometer due to price difference. CNG came 13–20% short in term of engine output torque and horsepower, most likely because incomplete gas combustion in the engine cylinder. CNG emitted lower carbon oxides, but higher nitrogen oxides and hydrocarbons. The slow CNG flame speed seemingly caused relatively high proportion of unburnt methane. Interesting fact was that CNG performed better on rougher Route I than on Route II, demonstrated the suitability of CNG to heavy-duty vehicles.