Oil - For a Cause - Future Watch

Smooth, fast and stylish, the Mercedes-Benz C220CDI is one very desirable car. But what happens when you put some vegetable oil in its fuel tank? Here's what...

Story: Sameer Kumar Photography Kunal Khadse

Powered by a 2148cc, common-rail turbodiesel, the C220CDI packs 143PS and 324Nm of torque, which makes it quite a lot of fun to drive. It's responsive, handles reasonably well and is as plush and refined as you'd expect a Merc to be. Which are some of the reasons why Mercedes-Benz chose this car for their Biodiesel project.

The company wanted to show that bio-fuels are indeed a viable alternative and that neither performance nor fuel efficiency suffer on account of using such fuels. With the biodiesel C220, it is mission accomplished for them.

The current yearly consumption of diesel in India is in excess of 50 million tones and it's growing at a rate of around five percent per annum. And that, er..., is a lot. Also, India's vehicle population has increased more than eight times over the last two decades, and today, vehicles contribute about 70 percent to the total air pollution. With ever-increasing costs (and ultimately, dwindling supplies) of fossil fuel, the biodiesel initiative is DaimlerChrysler's step towards reduced emissions and sustainable mobility. The company wanted to work on establishing the viability of oil culled from the Jatropha plant, which can be used as a substitute for diesel. In India, the Jatropha plant can be cultivated on wastelands in Orissa and Gujarat, on which other crop will not grow. Hence, there is a dual advantage here - wasteland being put to good use, and fuel actually being cultivated by farmers, who have a lot to gain in return.

The Hohenheim University in Germany, which has extensive experience with Jatropha plantations in other parts of the world, has been partnering DaimlerChrysler in this biodiesel project. Also on board is the Central Salt & Marine Chemicals Research Institute (CSMCRI), an Indian Government-owned industrial research institute in with a mandate to reclaim wasteland in India. The trio has been working on the biodiesel project for around three years, and we though now might be a good time to pit a biodiesel C220 against a 'normal diesel' C220, and see how the two compare, in terms of engine performance. And as it turns out, the biodiesel Merc does quite well for itself. It sprints from zero to 60km/h in 4.96 seconds, to 100km/h in 11.76 seconds and hits a top speed of 212km/h. These figures are quite comparable to those of a C220CDI running on 'normal' diesel - zero to 60 in 4.94 seconds, to 100 in 11.44 seconds and a top speed of 215km/h. As you can see, the biodiesel car is only marginally slower, and on the road, there is no discernible difference in acceleration and drivability. Brilliant stuff, this veggie oil!

In the last three years, DaimlerChrysler's biodiesel project has focused on selection of appropriate land in Orissa and Gujarat, survey for the availability of Jatropha seeds (for the production of about 1000 litres of biodiesel), and optimisation of the transesterification process, to make sure that the biodiesel produced conforms to European emission standards. Now, the focus is on optimisation of Jatropha plantations, the harvesting of seeds, and optimisation of oil extraction and transesterification, with emphasis on economy and quality. To make biodiesel really viable, it would have to be priced competitively, and for that, production will need to be upscaled. This will happen with the added involvement of mineral oil companies, co-operatives and public agencies, which will hopefully result in large-scale reclamation of wasteland, and commercial-scale production and marketing of biodiesel.

Another important thing is, biodiesel is capable of lowering carbon dioxide emissions, and emissions of other harmful gases and particulates are also lower compared to ordinary diesel. Plus, biodiesel has a higher cetane number, with analysis showing >60 as compared to 49 for conventional diesel. And finally, biodiesel is low in sulphur and high in oxygen content, and features excellent lubricating properties - all of which bodes well for its use in automobile engines. In fact, after the thousand of kilometers over which the biodiesel-powered C220 has been tested, the engine's cylinder head was dismantled. And it was observed. that even though carbon deposits on the injectors were marginally higher than normal, the engine was in perfect condition as regards to cylinder walls, valves and cylinder head. Even the flame travel marks on the piston crown were quite ideal, with an equal propagation on all sides of the point of ignition. The engine oil was also analysed, and while viscosity had increased slightly (compared to a car run on normal diesel), water content and iodine number, which is a measure for oxidation stability, were about the same.

One major performance parameter in using an alternative fuel is full load performance of the powertrain, and Mercedes-Benz conducted a full load, full throttle engine test on the biodiesel-powered C220. A marginal power drop of about three percent was observed, though torque curves were about the same. Carbon Monoxide emissions increased slightly, while particulate emissions showed significant reduction. Overall, the benefits outweigh the negative aspects by a healthy margin and if cultivated successfully, and in large enough quantities, there's much hope for Jatropha-derived biodiesel. Three cheers for vegetable oil then...