DOI: 10.1615/ICHMT.2017.CHT-7
ISBN Print: 9781-56700-4618
ISSN: 2578-5486
Numerical investigations on the performance of an engine fueled with gasoline-nbutanol blends
Краткое описание
In this work, the performance of a "downsized" spark-ignition engine fueled by gasoline and bio-butanol blends has been analyzed.
Experimental tests have been carried out at operating points ranging from low up to medium engine speed and load. The engine has been fueled with gasoline and butanol/gasoline blends B20 and B40 (20% and 40% butanol mass percentage)
The first investigations were aimed to assess the main differences among the different fuels in terms of output torque, efficiency, combustion duration and optimal spark timing. In order to reproduce the real world urban driving cycle, stoichiometric mixtures have been chosen.
Both the engine torque and thermal efficiency slightly decrease (about 4 percent) when the alcohol content increases.
Experimental results have been used to validate a 1-D model able to estimate the performance of an engine fueled by gasoline-butanol blends reproduce the whole engine lay-out.
When the concentration exceeds 40% of butanol there are problems of corrosion in engines normally in circulation. For this reason, the 1D model has been used.
By means of this model, calculations have been done in order to predict the engine performance at partial load operation of a downsized spark-ignition engine. Several n-butanol/gasoline mixtures, differing for the alcohol contents (B0, B20, B40, B60, B80, B100) been analyzed.
Results show that both torque and indicated efficiency decrease when small quantities of alcohol are added to the gasoline. On the contrary, when the engine is fueled by neat n-butanol, torque and efficiency reach values about 2 % higher than those obtained with neat gasoline.
Furthermore, the optimal spark timing, for alcohol-gasoline mixture operation, must be retarded (up to 13 %) in comparison with the correspondent values of the gasoline operation.