Abstract - Biofuel is an alternative fuel to reduce the dependent on fossil fuel due to the limited oil
stock and increment of oil prices. Straight vegetable oil (SVO) has several superior combustion
characteristics such as less hydrocarbons, carbon monoxide and particulate matter compared to
diesel fuel. More advantages are high biodegradability, excellent lubricity and no sulfur content.
During combustion, approximately 10wt% of its oxygen content promote more complete combustion
process and effectively reduce unburned hydrocarbons (UHC), carbon monoxide (CO) as well as
suspended aerosol carbon granules. However, high kinematic viscosity of SVO affects the spray
characteristics thus effect the engine efficiency. In this study, the effect of kinematic viscosity of SVO
on fuel injection spray characteristic are investigated using constant volume high pressure spray
chamber and nano-spark shadowgraph photography technique
