Factors Influencing the Composition and Quantity of Passenger Car Refueling Emissions-Part II

Refueling emissions from a 1986 Pontiac Grand Am were characterized using 3 test fuels, including a winter, summer and intermediate blend gasoline under a variety of seasonal temperature conditions. The effects of varying fuel volatility (10.1 to 13.3 psi RVP), dispensed fuel temperature (50 to 88°F), and vehicle tank fuel temperature (40 to 108°F), were investigated. Hydrocarbon (HC) emissions ranged from 2.90 to 7.41 grams per gallon of delivered fuel. Detailed hydrocarbon analyses were completed for both the test fuels (dispensed fuel and tank fuel) and the refueling emissions. The average (all test fuels and temperature scenarios) test gasoline composition was 46.1% paraffins, 6.3% olefins, 45.2% aromatics, with an average carbon number of 7.42; the average HC emission rate was 4.69 g/gal; and the average emissions composition was 81.4% paraffins, 12.2% olefins, 5.4% aromatics, with an average carbon number of 4.79. Butanes and pentanes comprised about 70% of the total HC refueling emissions.