The influence of deposit control additives on exhaust CO and HC emissions from gasoline engines (case study: Tehran)

Air pollution is the most serious environmental problem in Tehran with exhaust emissions from spark-ignition engines accounting for a major part of problem. The formation and accumulation of deposits on the internal surfaces of engines could adversely affect the exhaust emission from vehicles. It is the perception that some of fuel additives can remove these deposits due to their detergency. The Iranian Department of Environment decarbonized more that 250,000 SI engine vehicles in Tehran with the goal of reducing exhaust CO and HC emissions from gasoline engine vehicles by engine deposit removal. Here, the influence of engine deposit removal by decarbonization on the exhaust CO and HC emissions from more than 500 gasoline engine vehicles is examined. It is found that the decarbonization process could reduce the exhaust CO and HC emissions, significantly. Emissions from Peykan and Pride vehicles decreased considerably after decarbonization.