The control of vehicle evaporative and refuelling emissions – the “on-board” system

Report no. 88/62: In this research programme to further investigate "on-board"control of evaporative Volatile Organic Compound (VOC) emissions from gasoline fuelled vehicles, an Opel Ascona and a Honda Civic were tested with specially installed enlarged carbon canisters to control refuelling emissions. Both installations achieved refuelling emissions below 0.05 g/litre of fuel dispensed representing control efficiencies of about 97% or more. The total evaporative emissions as normally measured, being the sum of diurnal, hot soak and refuelling losses, were below 2 g/test with all the fuels used which ranged between 61 kPa and 103 kPa RVP.

No significant changes in exhaust emissions or in hot or cold weather driveability were seen between the standard and converted cars, and the tests demonstrated that regeneration of the canisters was achieved much more quickly than required to cope with the vapour from subsequent refuellings.