The paper presents a numerical model of car exhaust pollutant dispersion. The model can be used for estimation of the impact of pollutant emissions from road vehicles on the environment. The finite volume method has been used for model formulation. Equations obtained after discretisation are solved by using different methods like Runge-Kutta, Crank-Nicholson or decomposition methods. On the basis of the numerical simulation, conclusions are formulated about the numerical effectiveness of the integration methods used. In the paper, a problem of nitrogen oxides dispersion is formulated and solved, whereby chemical reactions are included in considerations. The model presented in the paper has been used for numerical calculations of car exhaust pollutant concentrations in a real car park. The last part of the paper presents some numerical results of calculations, which include emissions after cold start of engines.

Most countries in the world are facing two major challenges, one is the increase in the demand for energy consumption difficult to fulfill because of limited fossil fuel, and the second is the emission norms specified by many countries. Various methods are adopted to reduce emissions from engines but that leads to sacrificing the performance of CI engines. To eradicate this problem in the present study, the nanoparticles like (TiO2) are used with different particle sizes 10–30 nm, 30–50 nm and 50–70 nm induced in B20 (20% biodiesel and 80% diesel) with the constant volume fraction of 100 ppm, and utilized in the diesel engine without any modifications. The results showed that the incorporation of TiO2 nanoparticles improves the combustion of hydrocarbons and reduces the emissions of CO, unburned hydrocarbon concentration, NOx and soot. Moreover, among three sizes of the nanoparticles, those with size 30–50 nm showed interesting results with the reduction in brake-specific energy consumption, NOx, smoke and HC by 2.9%, 16.2%, 35% and 10%, respectively, com-pared to other blends used in the study, and hence the blend with the nanoparticle of size 30–50 nm is expected to be a more promising fuel for commercial application in CI engines.