resulting in slower burning and longer combustion duration. However, the
opposite trend was observed by Bittle [14] that biodiesel’s combustion
duration was shorter than petroleum diesel under low, medium
or high load. The cloud point and the pour point of biodiesel
are also higher than those of diesel which makes it very sensitive
to cold weather [15] and results in the difficulty of cold starting
[15,16]. Due to the oxygenated nature of biodiesel, the energy content
per liter of biodiesel is 5–12% lower compared to diesel. Combining
with the effects resulted from ignition delay and
combustion duration, the heat release rate of biodiesel is lower
than diesel, reducing the peak pressure rise rate, peak cylinder
pressure and power [3].