The effect of speed on power output, brake specific fuel consumption (BSFC), and thermal efficiency of an engine using ethanol is compared with gaso­line engine, is shown in Figs. 7.2 through 7.5.

The observations are listed below:

1. The power output of the ethanol engine is higher, compared to a gaso­line engine at all speeds.

2. The BSFC is improved with an ethanol engine, compared to a petrol engine.

3. The maximum thermal efficiency of an ethanol engine is higher than that of a petrol engine. The efficiency curve of an ethanol engine is flat for a wide range of speeds, which indicates that the partial-load efficiency is much better, compared with a petrol engine.

4. The engine torque is considerably higher for ethanol as compared to a petrol engine.

Figure 7.2 Effect of speed on power at different compression ratios.

Figure 7.3 Effect of speed on BSFC (brake specific fuel con­sumption).

Figure 7.4 Effect of speed on thermal efficiencies.

Figure 7.5 Effect of speed on the torque.