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The exhaust emission from modern vehicles is reduced by catalysts except for cold start phase. The difference in emissions for unheated catalysts is large and can reach several times higher than the emission for the heated thermal state of the engine. In the dyno tests, the analysis of the duration and volume of the emissions for harmful exhaust components: CO2 (carbon dioxide), CO (carbon monoxide), THC (total hydrocarbons), NOx (nitrogen oxides) at various climatic chamber operating temperatures, i.e. 0-30oC, for a vehicle meeting the EURO3 and EURO6 standards was performed. Stationary analyzers AVL AMA i60 were used to measure the emissions. The article presents the differences in the emissions for the cold-start phase of engine operation and the duration of time passing to a heated engine for vehicles powered by petrol and LPG (liquefied petroleum gas). The work shows the analysis of modal emissions as well as bag emission.

One of the important factors affecting exhaust emissions of car engines is driving resistance. A certain problem during the tests bench according to the driving cycle is the road load curve function, which is determined based on various methods. In the paper, the results of studies of the impact of the driving resistances on the exhaust gas emissions of CO (carbon monoxide), CO2 (carbon dioxide), THC (total hydrocarbons), NOx (nitrogen oxides) emitted by passenger cars with a SI engine, fuelled with petrol and LPG were presented. Tests were carried out in chassis dynamometer for road load coefficient determined by the road method and for type approval alternative method. The research was realized for NEDC (New European Driving Cycle) cold start tests for EURO 3 and EURO 6 standards vehicles. Results show that CO2, CO and THC emissions for tests realized by dyno settings based on road load are higher than for tests with dyno settings by the alternative method of the load.

The reduction in the toxic pollutant emissions in diesel engine exhaust gas is one of the main tasks of designers. Toxic substances emitted in diesel exhaust are, among other things, hydrocarbons. Reducing their emissions can be achieved by affecting the exhaust gases or reducing their formation in the combustion chamber. One method is to change the control parameters of the fuel injection process. In the present study, the direct injection diesel engine with a displacement of 1850 ccm was tested. The diesel engine was equipped with a prototype common rail injection system, allowing for the injection of a fuel quantity divided into three parts during one engine working cycle. Each part can be injected when the injector opens at certain injection advance angles. This results in six different control parameters. Such a number of parameters means a large number of combinations.

The legislative limitations of vehicle exhaust emission together with the current and prospective growth of road transportation intensity calls for continuous effort to improve vehicle powertrains that must be done both in design and technology domains. As the powerful remedy, a new generation of combustion engines fitted with the variable compression ratio (VCR) feature is considered. VCR technology can extend the range of clean engine operations such as HCCI or other advanced combustion strategies, enabling reduction of all exhaust harmful compounds simultaneously. There are several known technologies for performing variable compression ratio in combustion engines; some of them have been successfully tested in engine research rigs and/or vehicle prototypes. In the paper the proposal of application of variable compression ratio technology in four-cylinder, water-cooled engine is presented.