31 Aug 06
You can make your diesel car considerably more eco-friendly by fuelling it with biodiesel. Essentially, this is because biodiesel is carbon-neutral to use, because the CO2 produced when it is burned has already been absorbed from the atmosphere by the plants from which it is produced. It's clearly an elegant solution - and not only to slowing global warming (CO2 production) and reducing our dependency on fossil fuels.
Biofuels are virtually free from sulphur or metals. The particulates produced in the exhaust of engines that burn conventional diesel are partly created from these metals and sulphur. There are some health concerns with particulates, and even if these prove to be unfounded, it's a fact that particulates blacken buildings, so it's desirable to prevent them from being formed. Depending on the biofuel used, particulate emissions can be virtually eliminated.
And there's another reason why sulphur-free fuel is a blessing: if there's no sulphur in the exhaust emissions, you can use an exhaust after-treatment device called a denox catalyst. Diesel engines can produce significant oxides of nitrogen (NOx) in their exhaust, and these gases contribute to acid rain and respiratory problems. But sulphur-free fuel allows a denox catalyst to be used to good effect, converting NOx to harmless nitrogen.
Not that the advantages stop there. Another significant one is that biodiesel naturally has a high cetane rating. This is a measure of how readily diesel fuel ignites - the higher the rating, the better. This is most relevant in low winter temperatures when engine starting can be sluggish.
Oh, and we forgot to say that biodiesel has considerably better lubricity than normal derv, and that's vitally important to fuel-injection systems. While conventional diesel needs a package of chemical additives to boost its lubricity, biodiesel does not.
