This paper reviews the use of vegetable oils and animal fats as diesel
feul. Physical and chemical properties and structure of the vegetable
oils are discussed. Fuel preparation by transesterification, pryolysi
s, dilution, and microemulsion and the effects of these processes on t
he properties of the fuel and, in turn, their effects on the engines h
ave been reviewed. Each of the processes give improved fuel properties
over those of unprocessed vegetable oil. The performance of engines u
sing triglyceride based fuels and their emission characteristics are a
lso presented.