Exhaust gas dose uniformity in modern diesel engines

Currently, the environment protection challenges the designers and manufacturers of combustion engines due to the fact that the engine emits toxic compounds, which are hazardous to the life organisms. Increasingly strict regulations concerning emission of the exhaust gases forces application of the innovative technologies or improvement of the presently used. One of systems, which reduce the toxicity of the exhaust gases, is the Exhaust Gas Recirculation (EGR) system. This solution reverse part of the exhaust gases back into the manifold and mixes it with fresh inlet air. In consequence, the combustion temperature decreases. Less oxygen reacts with nitrogen and more connects with carbon and hydrogen. Presently there are two types of EGR system i.e. internal and external. In case of the first one part of the exhaust gases remains in the combustion chamber after the combustion but its construction is not complicated. The external EGR system uses one valve of the exhaust gas recirculation system located on the manifold. This location can result of the uneven portion of exhaust gases directed to the combustion chamber. In consequence, the decrease on the temperature is also uneven and therefore different portion of nitrogen oxide in the exhaust gases.