Abstract for presentation at 14th IUAPPA World Congress

One of the most important environmental problems in Iran is air pollution, especially in the capital city of Tehran. The exhaust emissions from spark ignition engines accounts for a major portion of this problem in Tehran. Nitrogen oxides are one of the main groups of pollutants in exhaust emissions from spark ignition engines. Engine deposits derived mainly from the gasoline could adversely affect the engine emissions. It has been observed in the majority of studies that the accumulation of engine deposits may lead to an increase in NO_x emissions. In line with Iranian department of environment policies to reduce Tehran air pollution, more that 250,000 SI engine vehicles were decarbonized in Tehran. In decarbonization process a mixture of gasoline and additive was injected into engine to remove engine deposits. In the present research, the influence of a deposit control additive on NO_x emissions from two types of gasoline engine vehicles i.e. Peykan (base on Hillman) and Pride (South Korea Kia Motors) was studied. Exhaust NO_x emissions from 192 Peykans and 227 Prides were measured in to stages, before decarbonization process and after that. Statistical analysis was conducted on the measurement results.
Results showed that NO_x emissions from Peykans increased 0.28% and NO_x emissions from Pride automobiles decreased 6.18% on average, due to the elimination of engine deposits. The observed variations were not statistically and practically significant. The results indicated that making use of detergent additives is not an effective way to reduce the exhaust NO_x emissions from gasoline engine vehicles.