A computer program which simulates the operation of a diesel engine is in current use at University of Wisconsin. The heat transfer in this simulation is computed using equivalent "steady state" temperatures for the various metal surfaces in the engine cylinder.
The objectives of this investigation were to predict the instantaneous temperature of the cylinder head and piston gas-side surface and to study the effect of using these varying temperature on the results of the cycle simulation.
A computer subroutine which solves numerically the one-dimensional conduction heat transfer equations for the cylinder head and the piston walls, at each time interval, was incorporated into the cycle simulation program.
Simulation runs were made at an engine condition for which experimental cylinder head surface temperature data were available.
Results show that for clean walls the simpler, steady state, cycle simulation gives adequate results for computing engine performance parameters.
When surface deposits are present, there are much larger variations in surface temperature and this makes it necessary to use the variable temperature model in the cycle simulation.
The computed cylinder head surface temperatures compared favorably with experimental data for amplitude and shape but there was a discrepancy in the absolute values of temperature
copyright 1967
Engine Research Center
University of Wisconsin-Madison