Fig. 3(a) and (b) shows the SFC variations depending on the speed of the engine. SFC increases at low speed, decreases at medium speed, and increases again at high speed in both the UE (a) and the CE (b) for all test fuels. The decrease in SFC was 4.9% for 2D, 5.8% for CME-100, 4.7% for CME-20, and 8.0% for CME-35 in the CE (b) compared with UE (a).