Use of a thermodynamic cycle simulation to determine the difference between a propane-fuelled engine and an iso-octane-fuelled engine

摘要

A thermodynamic cycle simulation of the four-stroke spark-ignition engine wasused to determine the effects of variations in engine design and operating parameters onengine performance and emission characteristics. The overall objective was to use theengine cycle simulation to determine the difference between a propane-fuelled and aniso-octane-fuelled engine for the same operating conditions and engine specifications.A comprehensive parametric investigation was conducted to examine the effectsof variations in load, speed, combustion duration, spark timing, equivalence ratio,exhaust gas recycle, and compression ratio for a 3.3 liter, Chrysler Minivan, V 6 engineoperating on propane. Parameters were selected for the analysis. Variations in the brakespecific fuel consumption, brake specific NOx emissions, and mean exhaust temperaturewere determined for both the propane-fuelled and the iso-octane-fuelled engines.Brake specific fuel consumption and mean exhaust temperature values for thepropane-fuelled engine were consistently lower (3 to 5 %) than the corresponding valuesfor the iso-octane-fuelled engine. Fuel structure did not have a significant effect on brakespecific nitric oxide emissions.Predictions made from the simulation were compared with some of the availableexperimental results. Predicted brake torque and brake power showed acceptablequantitative agreement (less than 10 % variation) in the low engine speed range (1,000 to3,000 rpm) and similar trends with the available experimental data.