The analysis of effects of the exhaust gas back pressure on performance and exhaust emissions of diesel engines

The requirment for sustainable energy production, forces diesel engine producers to develop more enviromental-friendly and more efficient motor models. Concordantly, exhaust gas aftertreatment systems to decrease exhaust emissions and exhaust waste heat recovery systems to increase thermal efficiency are the most frequently used methods for this purpose. However, any system installed on the exhaust pipe of diesel engines is a source of exhaust backpressure. Increasing the exhaust backpressure has negative effects on the performance and exhaust emissions of diesel engines. In this study, a comprehensive experimental study was conducted to make experiments and analyzes on issues not addressed in the literature to analyze the effects of exhaust backpressure on engine performance and exhaust emissions, and to verify and test the findings of previous studies. In the experimental study, the exhaust back pressure was increased by means of orifices installed on the exhaust line, and the effects of back pressure increment and engine load on various engine performance indicators were made by making measurements at 1600 rpm engine speed, 6 different engine loads and 5 different exhaust backpressure values. The findings were discussed in the light of the theory. According to the results of the study, increasing back pressure causes to retarding of combustion periods, causes to decrease of the maximum in-cylinder pressures, volumetric efficiency, fuel conversion efficiency, nitric oxide emissions and causes to increase of pumping loss, mechanical efficiency, brake specific fuel consumption, carbondioxide emissions and carbonmonoxide emissions. In the conclusion part of the thesis, suggestions are presented to reduce the negative effects of the exhaust back pressure increment.