Comparison of Vehicle Exhaust Emissions with Gasoline Engines of Different Ecological Classes in Road Tests

Abstract

The introduction of changes in the vehicle type approval testing procedures is a way to reduce the issue of exceeding the limits set in the standards. Previous laboratory tests of vehicle emissions did not contain information on the actual vehicle and engine operating conditions. Therefore, particular attention was paid to comparative tests of gasoline engines in the context of the particles number and nitrogen oxides road emission. The reason for this was a significant discrepancy in the ecological classification of engines (Euro 6 and Euro 6d-Temp) for vehicles of similar weight. The article presents the assessment of ecological vehicle indicators in real traffic conditions in accordance with the latest RDE (Real Driving Emissions) test proposals. It has been shown that despite the compliance of vehicles with emission limits of nitrogen oxides and the number of particles in tests carried out in the chassis dynamometer test, they are varied in real operation conditions. This proves that special attention should be paid to gasoline engines, which emit much more solid particles than the latest emission class compression-ignition (Euro 6d-Temp) engines. At the same time, the development of the automotive industry, new engine designs fueled by alternative fuels and the use of hybrid drives should constantly include the latest emission testing procedures.