Evaporative emissions: developing australian emission algorithms

Evaporative emissions from motor vehicles contribute significantly to hydrocarbon emissions in urban areas. This contribution is typically in the order of 10-25% of total HC emissions from road transport, but contributions up to about 60% have been reported. Given the importance of hydrocarbon emissions for modelling of photochemical smog and secondary particles, as well as quantification of the levels of exposure to specific hydrocarbons (benzene, toluene, etc.), accurate estimation of evaporative emissions is vital. This paper discusses the development of emission algorithms from Australian and European test data, which have been incorporated in the COPERT Australia software program. Differences between Australian and European technologies (canister size, fuel tank size, etc.) are discussed. The algorithms are then used to estimate total evaporative emission loads for Queensland and these estimates are compared to predictions for other types of emissions (hot running, cold start).