Tractor vaporising oil
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Tractor vaporising oil (TVO) is a fuel for
History
TVO existed for at least fifteen years before it became widely used. A 1920 publication mentions it as a product of
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.
Octane rating
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
Fuel | Octane rating | Notes |
---|---|---|
Petrol | 98 | - |
Kerosene | 15-20 | - |
Paraffin | 0 | - |
Diesel fuel | 0 | - |
Petrol (pbv) |
Heating oil (pbv) |
Octane rating |
---|---|---|
1 | 0 | 98 |
2 | 1 | 72 |
1 | 1 | 59 |
1 | 2 | 46 |
0 | 1 | 20 |
- pbv = parts by volume
The words paraffin and kerosene are often used interchangeably but the tables suggest that this is incorrect because they have different octane ratings. However, kerosene and heating oil have similar octane ratings. Paraffin, kerosene and petrol (gasoline) are all rather loosely defined. For example, gasoline may have an octane rating between 88 and 102.
Engine modifications
Compression ratio
Because TVO has a lower
Vaporiser
In practice TVO had most of the properties of paraffin, including the need for heating to encourage vapourisation. As a result, the exhaust and inlet manifolds were adapted so that more heat from the former warmed the latter. Such a setup was called a vaporiser. To get the tractor to start from cold, a small second fuel tank was added that contained petrol. The tractor was started on the expensive petrol, then – once the engine was warm – the fuel supply switched over to TVO or paraffin. So long as the engine was working hard, as when ploughing or pulling a load, the TVO would burn well. Under light conditions, such as travelling unloaded on the highway, the engine was better on petrol.
Radiator blind
Some tractor designs included a radiator "blind" that would restrict the flow of air over the radiator which led to the engine running hotter, which could help with starting. If the radiator blind was left shut, though, there was a risk of engine damage, especially in warm weather.
Terminology
The phrase petrol-paraffin engine is often used to describe an engine that uses TVO. This can be interpreted either as
- the use of the two fuels, starting on petrol then switching to the paraffin-based TVO
- the use of a mixture of petrol and paraffin as a substitute for the proper TVO
Supply
TVO was withdrawn from sale by UK suppliers in 1974. An approximation to the correct specification can be made from
North American distillate fuel
In North America a similar product, called distillate, was produced. Of lower quality than TVO, its octane rating varied between 33 and 45. Manufacture of tractors using distillate ended by 1956, when gasoline and diesel-engined tractors had captured the North American farming equipment market.[6][7]
Notes and references
- ^ Editorial staff (1920), "News column", The Commercial Motor, vol. 31, Temple Press Limited.
- ^ a b "Tractor Vaporising Oil". 2005-04-18. Archived from the original on April 18, 2005. Retrieved 2014-08-11.
{{cite web}}
: CS1 maint: unfit URL (link) - ^ "Friends of Ferguson Heritage Ltd.- TVO Recipes". Fofh.co.uk. Retrieved 2014-08-11.
- ^ "Friends of Ferguson Heritage Ltd.- TVO Recipes". Fofh.co.uk. Retrieved 2014-08-10.
- ^ "HCOTEG12780". Hmrc.gov.uk. Retrieved 2014-08-09.
- ^ "Tractor Fuel Types". TractorData. Retrieved 3 September 2021.
- JSTOR 44467751. Retrieved 3 September 2021.