Effects of Biodiesel Fuels Produced from Vegetable Oil and Waste Animal Fat on the Characteristics of a TDI Diesel Engine

Abstract

In this study, four different biodiesel fuels obtained from corn oil, safflower-rapeseed oil mixture (50%-50% v/v), waste chicken fat, and waste fleshing oil were tested in a six-cylinder, water-cooled, TDI diesel engine. Vegetable oil and waste animal fat origin biodiesel fuels’ effects on the performance, injection, combustion and emission characteristics of test engine were compared with each other and petroleum-based diesel fuel as reference fuel. Biodiesel fuels (regardless of their feedstock) increased in-cylinder gas pressure, brake specific fuel consumption, and NOx emissions while decreased THC and CO emissions compared to pure diesel fuel. In comparison to petro-diesel, the start of fuel injection timing advanced but the end of fuel injection timing retarded with biodiesels. In addition, comparatively higher fuel injection pressure values were attained with all biodiesel fuels. Waste animal fat and vegetable oil origin biodiesel fuels showed similar in-cylinder gas pressures, fuel injection characteristics and brake specific fuel consumption values. However, CO emissions of vegetable oil-based biodiesel fuels were lower and NOx emissions were higher than those of waste animal fat-based biodiesels.