The article presents issues related to the assessment of concentrations of harmful substances in the exhaust gas cloud behind a compression-ignition passenger vehicle. The introduction describes issues related to the impact of air pollution on the environment and on human health and life expectancy. The article presents exhaust gas dispersion tests behind the vehicle were carried out both in stationary conditions (a specially prepared laboratory stand) and in real operating conditions. PEMS testing equipment was used for this type of measurements. During the measurements, concentrations of harmful exhaust gas compounds were analyzed in relation to the distance of the measuring probe from the exhaust system. In stationary conditions, the influence of the engine speed on the dispersion of pollutants was also studied. The tests carried out show that the concentrations obtained behind a moving vehicle significantly decrease with the distance of the measuring probe, and their dispersion is much smaller in most cases than in the case of stationary tests. This is the basis for recognizing that thanks to this, it is possible to analyze the concentrations obtained and conduct tests using the emission gate.
The basic problem in terms of measuring exhaust emissions is the approval tests of traction vehicles, which are carried out on engine dynamometers. Therefore, it is impossible to obtain reliable results concerning their actual impact on the natural environment. It is therefore advisable to carry out the tests in real operation conditions, as is the case for road vehicles for which RDE (Real Driving Emissions) tests are carried out. The latest Stage V emission standards push for the introduction of this type of test, but no limit values for toxic exhaust gases have been established and no test guidelines have been defined for assessing actual emissions. This article describes the issues related to the legislative guidelines for non-road vehicles in force in Europe, as well as the measurement tools used, such as mobile equipment for measuring emissions of PEMS (Portable Emissions Measurement Systems) and newly developed emission gates. Additionally, the paper presents examples of locomotive exhaust emission tests in real operating conditions. The aim of the measurements was to assess the emission of toxic compounds against the relevant standards. The subject of the research was a diesel locomotive type T448.P equipped with a modernized internal combustion engine.
The article presents toxic exhaust components emission measurement results as well as solid particles mass and number. The test involved a direct gasoline injection engine, in which special attention should be paid to the particulates number emission. Small diameters of nanoparticles make them particularly dangerous to human health. Nowadays, vehicle engines are constantly improved and modernized as a result of the need to meet existing exhaust gas emission standards. One of the few ways to determine the actual content of toxic and harmful compounds in the exhaust gases is the RDE (Real Driving Emissions) procedure, the requirements of which apply from 2016 for new vehicles, and from 2019 will apply to all registered passenger cars. The RDE procedure does not replace the WLTP (World Light-Duty Vehicle Test Procedure), but complements it. The tests on the dynamometer are separated from external conditions such as traffic volume or congestion and are not a sufficient indicator of emissions in real traffic conditions.
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