Never mind Esso’s suggestion to ‘put a tiger in your tank’; we could soon be putting a pig in our petrol.Well, diesel, actually. American oil company ConocoPhillips and food producer Tyson Foods have announced a plan to produce diesel from pork, beef and chicken fat.The processed animal fats will be turned into a kind of diesel similar to biodiesel, and with the same chemical properties as oil-based diesel.That means that engines will require no modification to run on the animal fuel. The fat is a by-product from Tyson – the world’s largest meat producer – and is currently used for making soaps and cosmetics.We don’t understand the technology behind it, but ConocoPhilips and Tyson say that it will create a low-sulphur fuel. According to the two companies, “Using a proprietary thermal depolymerization production technology, the animal fats will be processed with hydrocarbon feedstocks to produce a high-quality diesel fuel…The addition of animal fat also improves the fuel’s ignition properties, while the processing step improves its storage stability and handling characteristics.”If things go to plan, the fatty fuel will be on sale in the US by the end of 2007, and should account for around three per cent of ConocoPhilips’ total output, or 175 million gallons of animal diesel a year. The porcine petrol may even make it to Europe: the first tests were carried out at ConocoPhilips’ plant in Cork, Ireland.We’re just hoping that the exhaust fumes smell like a bacon sarnie.