This paper addresses the use of neat, indigenous biodiesel in advanced Mercedes-Benz passenger cars. Modern, unmodified EU3 Common-Rail diesel engines with second generation common rail technology were used to determine the effects of neat biodiesel on performance and emission characteristics. The biodiesel was made from the seeds of the Jatropha Curcas plant and sourced from the Central Salt and Marine Chemicals Research Institute in Bhavnagar, India. The production of biodiesel and the vehicle tests are part of a PPP project, funded jointly by the DaimlerChrysler AG and the German DEG. The project aims at providing additional jobs and income in rural Indian areas along with reclaiming unused wasteland.
The test vehicles were operated for a cumulative 8000 kilometers with an intention to expose the vehicle and fuel to diverse climatic conditions. During the tests the vehicles were subjected to periodic emission testing in order to determine the on-road emission performance and identify key emission characteristics of the Jatropha Methyl Ester (JME). Storage stability testing as well as engine performance testing of the JME was conducted to determine the respective quality and performance parameters. The first vehicle-testing period revealed that the car running on biodiesel shows no particular deviation from a car running on fossil diesel as far as vehicle performance is considered.
The hydrocarbon and nitrogen oxides emissions are comparable to that of fossil diesel, however carbon monoxide emissions tend to increase. In order to come to a final conclusion, a larger sample size of tests needs to be considered as the variations are in a small bandwidth. Particulate emissions from the vehicle running on JME were significantly lower than those of a car running on fossil diesel. This can be considered as a conclusive outcome considering the two cars being tested so far.
The quality of the biodiesel, produced in a small scale, all Indian-made transesterification unit, exceeds the stringent requirements of the EU 14214 norm. Only the storage life of the biodiesel is a parameter which needs to be studied further as a negative variance with regards to emission performance was observed with biodiesel under long durations of storage. This is a well-known feature of biodiesel which can be remedied by using appropriate additives.
In order to come to a more conclusive understanding of the performance of biodiesel made from the Jatropha Curcas plant in Mercedes-Benz Common Rail Diesel engines, further testing with this vehicle over a distance in the region of 45000 to 55000 kilometers is under way. Additional testing under hostile and harsh environmental conditions will also be carried out to ascertain full fuel performance.