THE USE OF AN ENGINE CYCLE SIMULATION TO EXAMINE ALCOHOL FUELS FOR A SPARK-IGNITION ENGINE

摘要

The use of alcohol fuels in spark-ignition engines has been well established for over 100 years through extensive experimental and numerical studies. The current work examines the detail thermodynamics of the use of methanol and ethanol by an automotive, spark-ignition engine. Both overall engine performance parameters and detail instantaneous quantities are determined as functions of engine design and operating conditions. In addition, the results for alcohol fuels are compared to results for isooctane. Results include brake power, torque and efficiency as functions of engine speed and load. Operating conditions include constant equivalence ratio (stoichiometric), MBT spark timing, and constant burn duration. All results are for constant load (bmep = 325 kPa) which results in a more open throttle for the alcohol fuels. For the conditions examined, the alcohol fuels resulted in higher efficiencies, lower nitric oxides, and less exergy destruction during the combustion process. The results are explained by detail knowledge of the relative heat transfer, pumping losses and cylinder gas temperatures.