A theoretical study on the heat transfer process in diesel engines

Abstract

The current and future emissions regulations and demands on internal combustion engines have increased the need for improvement of the thermal design and engine ef ciency. This paper reports an initial investigation concerning in-cylinder heat transfer. In addition, a literature review in this eld is presented. It was found that no extensive application studies have been performed on full cylinder heat transfer by taking the effect of combustion and gas exchange into the account. The available literature is mainly focused on individual component studies and sub-model improvements. Furthermore, a simple parameter study is performed in order to estimate the contribution of each parameter on the in-cylinder engine heat transfer. This is done by setting up an engine segment, using the commercial CFD tool AVL FIRE and the automatic mesh generator AVL Ese Diesel. Engine segment simulations are made for the period between IVC (intake valve closing) and EVO (exhaust valve opening). The parameter study revealed that most of the parameters selected do in-fact signi cantly affect the in-cylinder heat transfer. However, the effects on the indicated mean effective pressure, or indicated power output, are different. (Less)