Influence of Dynamically Changing Operating Conditions on the Content of Nitrogen Oxide in Old and New Diesel Vehicles

The conditions of actual operation of the vehicle in certain cases differ from the standard conditions of application of the relevant standard for determining the content of toxic components in the exhaust gases. This leads to an incorrect estimate of the absolute volume of toxic emissions released into the atmosphere. Nitrogen oxides in the exhaust gases of diesel cars are significantly affected by the dynamics of the operating mode, as well as the engine load. This trend is particularly negative for older diesel cars, which do not have the option of additional neutralization of exhaust gases. Under the conditions of the car fleet of the Republic of Bulgaria, which has an average age of 18 years, this problem is essential. For the objective assessment of the actual amount of nitrogen oxides emitted in the exhaust gases, planned experiments have been conducted in which extreme acceleration processes and loads of the car are artificially simulated. The experiments were performed on a car that meets the requirements of the EURO3 standard (18 years old) and on a new car according to the EURO 6D - TEMP standard. Conclusions have been made regarding the high level of neutralization of nitrogen oxides in the exhaust gases of vehicles with catalytic reduction.