Abstract
Acquiring any precise Pressure/Volume diagram (or ‘PV’ diagram) throughout IC-engine working cycle has been critical on determining internal combustion engines performance. Due to the complexity of this type of measurement, numerous experimental analysis of IC-engine research has been purposed without pressure versus cylinder volume data being taken. Besides measuring engine input parameters (i.e. engine fuel flow, intake manifold temperature), engine’s exhaust gas provides numerous details of engine running conditions (i.e. oxygen percentage remaining in residual gas). However, the information inside exhaust gas temperatures itself cannot provide an accurate measurement of engine cycle heat losses because of a relatively large heat transfer to engine cooling system during the exhaust process. Considering the traditional IC engine’s four-stroke cycle and nature of reciprocating piston motion, excessive heat losses happened during combustion period and expansion stroke decrease engine cycle efficiency. Most chemical energy from the fuel is released around Top Dead Center (or ‘TDC’), and the piston is moving at a low velocity around both TDC and BDC (Bottom Dead Center). Consequently, heat flux around engine TDC is relatively higher than any other piston positions. Heat losses during the exhaust or intake process do not affect engine cycle efficiency. This work allows for the differentiation of heat losses during combustion period and expansion stroke without measuring cylinder pressure versus cylinder volume data. A general view of energy flow throughout the entire engine working cycle is feasible by the generated PV-diagrams. Through regenerating PV diagram, the percentage of energy flow rejected into coolant system as heat loss is quantized by adjusting computer model’s inputs to match real experimental data. Additionally, besides using Woschni’s correlation, some other heat-transfer correlations were implemented and testified for further comparisons.