Experimental analysis of the global energy balance in a DI diesel engine

The increasingly stringent internal combustion engines (ICE) emissions regulations, has led to the extended use of after-treatment systems, giving progressively more importance to the engine efficiency optimization. In this context, the experimental methodologies to perform and analyse the energy balance show as a key issue to evaluate the potential of different engine strategies aimed at the consumption optimization and the improvement paths identification. This works deals with the complete description of an experimental energy balance tool, including the comprehensive description of the specific designed experimental installation used to the determination of each energy term involved in the energy balance. After the tool description, a study of the energy balance in the engine map of a DI Diesel engine was carried out, with the objective of determining the engine speed and load influence on each energy term. A subsequent parametric study varying the coolant temperature, the intake air temperature and the start of the injection (SOI) and their influence in the engine efficiency has been performed. The results shows that the variation of the coolant temperature has an almost negligible effect in terms of efficiency whilst cooling the air yields in an improvement about 1% and advancing the SOI about 1.5%.