Barat Ghobadian - Associate Professor، Tarbiat Modares University,Tehran-Iran
Gholamhassan Najafi - Ph.D.Student، Tarbiat Modares University,Tehran-Iran
Hadi Rahimi - M.E.Graduated، Tarbiat Modares University,Tehran-Iran
Ali Mohammad Nikbakht - Ph.D.Student، Tarbiat Modares University,Tehran-Iran

Under time domain analysis various operations are performed on digital time history records of the signals in the time domain itself to yield information on rates,commencement,duration and end of events,and identification of different phases of any process.This kind of analysis often required some intermed iate stages of data processing.In this paper,analysis of combustion parameters in a DI diesel engine which has been performed in the time domain yielded the followings:estimates of cylinder pressure derivatives,estimates for start of injection and ignition delay,estimates of the duration of fuel injection along with the start of dynamic fuel injection,estimates of the heat release descriptors,identification of the phases of c ombustion and estimates of their duration,identification of the phases of liner vibrations vis-à-vis their origin.The analysis procedure relating to these parameters has been discussed in this paper.Besides the directly controlled parameters of engine speed (N),load torque (Tr)or engine power and fuel injection timing ,the derived parameters identified combustion parameters are peak cylinder pressure [Pc]max,maximum rate of cylinder pressure rise [P •c]max,maximum accelaration of cylinder pressure [P ••c]max,peak rate of heat release [Q •]max which have been investigated in this paper.

Combustion parameters,time domain analysis,cylinder pressure ,heat release,ignition delay