Pollutant Emissions Comparison in a Cursor9 Heavy Duty Vehicle Engine Fuelled with Different Energy Sources

The objective of this thesis is an emissive comparison between two different same-rated heavy-duty engines fuelled with different energy sources. The engines are both Cursor-9, one CI and the other SI. The energy sources used are Diesel (taken as reference), CNG and a Diesel-like paraffinic fuel commercially named HVO. All the tests have been carried out in the FPT Industrial testing facility. They are a set of engine bench tests and a set of In-Service-Conformity and PEMS tests. After the introduction to the regulatory environment and the description of the data set, some information taken from papers are reported as starting point. A sort of state of the art, in which all the problems, expectations and research results are collected and critically analysed. From papers is clear that CNG cannot offer an optimal solution for pollutant emissions, but only a good reduction of CO2. The HVO offers a good reduction of pollutant emissions with respect to Diesel, especially if the analysis is carried out on CO2 again but enlarged on Well-To-Wheel. From the subsequent analysis of tests data, the expectations for CNG are satisfied, while for HVO is clear that the trade-off soot-NOx is not shifted down as expected. The causes are mainly two: firstly, the tests results are collected at tailpipe and not at engine outlet (so there is a conformity in pollutant emissions between Diesel and HVO mainly due to the ATS action), secondly the calibration dataset is kept unchanged, even though for HVO a slightly modification should have been done. So, the main conclusion is that as far as CO2 emissions are concerned, CNG and HVO are good alternatives for Diesel, while for the other pollutants the situation is unchanged and the need for a better ATS or a better dataset calibration is clear. The thesis is concluded with a paragraph about future developments, moving our point of view towards future regulations and Euro-VII expectations. Finally, the tool V.E.C.T.O. is introduced, with the results of the analysis carried out on the engines under study as an example. This tool is the one used by the European Environment Agency in order to collect data about CO2 average emissions and to set the future regulatory limits.