The study of predicting hydrocarbon vapor generation in the automotive evaporative emission control system

摘要

The hydrocarbon(HC) emission from automotive vehicles has been named as a source of the ozone layer depletion. Therefore, the importance of Evaporative Emission Control(EEC) system which can reduce HC emission is brought forward. EEC system iscomposed of a fuel tank, a fuel-returning line, a roll-over valve, an orifice for pressure regulation, tubes, and a canister. The canister is the centerpiece of EEC system that captures HC vapor escaping into the atmosphere and its optimal capacity isdecided by the amount of HC vapor generated during test periods. In this study, the mathematical model of the HC vapor generation in EEC system was constructed and solved according to testing conditions. The fuel vapor was considered as an ideal gasmixture of 35 different HC species. The pressure rise in the tank due to vapor generation causes the mixture of the fuel vapor and the air to pass through EEC system including the canister where the fuel vapor is captured. The Reid Vapor Pressure(RVP)decrease of the remaining fuel was calculated and the amount of vapor generated in the tank and captured in the canister was predicted. In addition, the obtained results were compared with experimental results.