Comparison of performance and emissions of a CRDI diesel engine fuelled with biodiesel of different origin

In the present paper, laboratory produced, animal origin biofuels (swine lard and turkey lard had been used as raw material for biofuel production) were evaluated in terms of physicochemical parameters and compared with commercial mineral diesel fuel and its mixture with rapeseed oil methyl esters. Basing on the results of physicochemical parameters assessment, mixtures containing 75% share of bio-component were preselected for further engine tests. The engine tests were performed on a medium-duty, turbocharged, Common Rail, Direct Injection (CRDI) diesel engine, using factory control maps. The scope of experiments included steady state measurements for two rotational speeds (1500 and 3000 RPM), for which full load sweep had been performed. Two injection strategies were utilized: single pulse (for 3000 RPM) and multi-pulse injection (1500 RPM). The research covered evaluation of engine performance parameters and full exhaust emissions. Furthermore, detailed combustion analysis was performed. The study confirmed that high quality fuel can obtained from waste fatty material. The mixtures containing up to 75% of bio-component are suitable for modern CRDI combustion engines, though slight deterioration of engine performance parameters can be expected. An average brake specific fuel consumption increased by 13% compared to reference, for biodiesel mixtures derived from animal fatty material. At the same time a 3% increase against rapeseed oil/diesel mixture was recorded. This was correlated with a minor reduction of brake fuel conversion efficiency, but the average drop didn't exceed 2% for all examined biodiesels. A significant reduction in exhaust gas emissions was observed, when comparing biofuel operation to reference diesel. The use of swine lard methyl ester/diesel mixture caused average reduction of hydrocarbon concentration (THC) by 13%, carbon monoxide (CO) by 22% and carbon dioxide (CO2) by 7%. The turkey biodiesel emission results were respectively: 9%, 20% and 6% reduced. NOx emission increased on average by 7% for both animal origin biofuels.