First Law Analysis of Diesel Engine Performance Using Diesel and Bio-diesel Fuel

In this study, the performance of a single cylinder four stroke direct injection (DI) diesel engine is analyzed in the light of first law of thermodynamics. An energy balance study is carried out to quantify the various losses associated with diesel engine processes on the basis of experimental performance and emission data. The engine was fuelled with normal diesel and Jatropha Methyl Ester (JME) in order to obtain experimental results corresponding to steady state engine operations at full load. For both the fuel operations at full load, the energetic performance parameters of the engine were evaluated. The results showed lower brake thermal efficiency (BTE) and higher fuel consumption in respect of JME. From the energy analysis, it was seen that the fuel energy input was more with JME due to higher fuel consumption although the fuel calorific value was less for JME. The indicated power (IP) produced by the engine with JME operation was comparatively higher. The energy loss with the exhaust gases was marginally higher and the loss of energy due to cooling was slightly lower for the JME. However the unaccounted heat losses were significantly higher and this was the reason of lower BTE with JME. The viscosity of JME was higher (5.03 cSt) compared to diesel (2.2 cSt) and may be due to higher viscosity, the JME fuel did not atomize properly resulting in poor combustion. The combustion efficiency was found to be less with JME and higher losses of energy due to combustion inefficiency resulted in higher unaccounted losses and hence lower BTE with JME.