Influence of the single EGR valve on the concentration level of selected toxic compounds in exhausts of a multi-cylinder compression ignition engine

The most important problem faced by engineers constructing modern combustion engines is to meet stringent standards for the emission of toxic and harmful compounds in exhaust gases. One of the ways to reduce the emission of toxic compounds, in particular nitrogen oxides, is the use of various configurations of EGR systems in single and multi-cylinder engines. Its task is to introduce a certain amount of exhaust gas into the combustion chamber, which directly affects the combustion process, and ultimately the reduction of nitrogen oxides. However, the effectiveness of the EGR system is usually presented basing of emissions reduction or decrease of toxic compounds concentration in the exhaust manifold system, without division into the share of emissions from individual cylinders.

This article presents the results of the tests carried out in order to verify the degree of uneven distribution of concentrations between cylinders of a multi-cylinder engine with the use of a single EGR valve. As a research object, a compression ignition engine with symmetrical intake manifold and a centrally located EGR valve was used. (paper)