5. Results and discussion
The performance of engine is greatly influenced by sources of bio-diesel, for example engine fuelled with palm oil bio-diesel is more efficient than bio-diesel produced from tallow and canola oil. Bio-diesel is likely to produce less power with high fuel consumption than diesel as the gross calorific value (energy content) of bio-diesel is lower than petroleum diesel. Blends of bio-diesel with petroleum fuel are widely used in diesel engine although the high viscosity of the fuels causes fuel flow and ignition problems in unmodified CI (compression ignition) engines and also decreases in power output. The lubricity and oxidative stability of the animal fat-based bio-diesels are better than soy-based bio-diesel. The results of performances and emissions of bio-diesels tested in this study (bio-diesel A and B) compared to diesel are presented and discussed in this section, as follows.