The impact of changing engine's operational parameters on its emission

The share of vehicles powered by compression ignition engines is constantly growing. The roots of this tendency are mainly of economic nature: diesel fuel is cheaper than petrol, and additionally compression ignition engines have higher efficiency than spark ignition engines. The growing number of vehicles also means that they start to impact the environment significantly. The vehicle-related emission of harmful substances is regulated by EURO emission standards in Europe. To satisfy them, engines must be equipped with additional exhaust after treatment systems such as exhaust gas recirculation (EGR) systems, catalytic reactors or diesel particulate filters (DPF). The fuel injection system, and more specifically its control strategy, responsible for controlling the time, manner and quantity of fuel delivered to the combustion chamber, significantly affects the emissions. When faced with problems in satisfying the requirements of the exhaust gas emission standards, many manufacturers attempt to limit the emissions by modifying the engine control strategy. The article discusses the problem related to the evaluation of the possible ways of limiting the emissions by modifying the engine's control parameters as performed by one of the leading car makers. The emissions of a car with an engine for which the manufacturer prepared a software control update aiming to curb the emission were measured in real life conditions. The tests were performed with the standard software and after its update. The results have shown that emissions of certain compounds can be limited without worsening operational parameters. (paper)