The influence of the size and shape of the “central body” of a combustion chamber on the toxicity of the exhaust gases in the Ursus 4390 engine

This work is the third part of the articles published on the effects of the shape and position of the combustion chamber in piston compression diesel engines on the toxicity of exhaust gases. In two previous articles presented at the KONES 2015 conference, the impact of position of the combustion chamber in relation to position of the injector, and the influence of the shape of the chamber (diameter, depth, lip on the CO, HC and NOx emissions was analysed. In the current article, the shape of the “central body” in a combustion chamber is analysed. “Central body” is the protrusion located in the central part of a toroidal combustion chamber. Subsequent modifications to the basic combustion chamber consisted of reducing the size of this protrusion. The study involved four versions of combustion chambers. Modifications caused a slight decrease in the compression ratio, which could have an impact on the unambiguousness of the results, as the effect of changes in shape of the “central body”. However, to maintain a constant compression ratio would require a change in diameter or depth of the chamber cavity, which would obscure the obtained results with even greater impact. Emission tests in discussed study were performed according to ECE-R4. During the tests, the completion of the engine and the engine settings were not changed.