Tractor vaporising oil

Tractor vaporising oil (or TVO) is a fuel for petrol-paraffin engines. In the United Kingdom and Australia, after the Second World War, it was commonly used for tractors until diesel engines became commonplace. In Australian English it was known as power kerosene.

TVO existed for at least fifteen years before it became widely used. A 1920 publication mentions it as a product of British Petroleum. But it was not until the late 1930s that it first became widely used. The post war Ferguson TE20 tractor, a carefully researched and near-ideal tractor for use on British farms, was designed around a petrol (gasoline) engine, the Standard inline-four. Although there was a campaign for the reintroduction of agricultural Road Duty (tax)-free petrol, which had been curtailed during the war, this was not forthcoming. Perkins Engines supplied some conversions into diesel engines which could use untaxed red diesel.

On the early Fordson model N, the tap which changed over from petrol to TVO was marked G for gasoline and K for kerosene, reflecting that these tractors had their design origin in the USA. In the UK tractor vaporising oil was usually called TVO.

As a substitute for petrol, TVO was developed. Paraffin (kerosene) was commonly used as a domestic heating fuel and was untaxed. Paraffin has a low octane rating and would damage an engine built for petrol. The manufacture of paraffin involves the removal of aromatic hydrocarbons from what is now sold as heating oil. These aromatics have an octane rating, so adding some of that otherwise waste product material back in a controlled manner into paraffin gave TVO. The resulting octane rating of TVO was somewhere between 55 and 70.

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