The effect of gasoline voatility on vehicle exhaust emissions at low ambient temperatures
Eight European vehicles, four of which were equipped with 3-way catalysts,have been tested on two gasoliries with significantly different front-end midrange volatilities. The investigation was conducted over the new ECE + EUDC test cycle at various ambient temperatures.It was found that emission levels varied widely between individual vehicles and that the effect of fuel volatility on emissions was much less than the effect of temperature.Carbon Monoxide (CO) and Hydrocarbon (HC) emissions increased dramatically as test temperature was reduced. For catalyst cars, CO emissions increased by over 500 per cent and HC emissions by around 300 per cent as the temperature was reduced from 25 to -5OC. NO, emissions were much less affected by test temperature.