Energy demand and emissions of a passenger vehicle fueled with CNG, gasohol, hydrous ethanol and wet ethanol based on the key points of the WLTC

A compact sedan vehicle powered by a 1.4 dm(3) spark ignition engine fueled with compressed natural gas (CNG), Brazilian gasoline, hydrous ethanol 95% v/v and wet ethanol 88% v/v was evaluated throughout the Worldwide harmonized Light vehicles Test Cycle (WLTC) key points. The vehicle operating points with longest residence time on the WLTC were selected to fuel consumption and emissions evaluation at steady state conditions. The top five key operating points reported in this work accounted for 22% of the total time spent in the entire cycle. The results indicated a significant reduction on greenhouse gases (GHG) emissions and energy demand for operation with CNG. The ethanol-water blends provided reduced emissions of nitrogen oxides (NOx), but increased specific fuel consumption, carbon monoxide (CO) and GHG emissions in comparison to CNG and gasoline. The operation with gasoline resulted in the minimum CO emissions for all fuels tested, as well as the best fuel consumption between liquid fuels, despite the highest values of carbon dioxide (CO2), and increased NOx. Even though ethanol produced little total unburned hydrocarbons (THC), the emissions of alcohols and aldehydes raised an alert for this renewable fuel, whereas CNG emitted the least amount of such pollutants.