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Tractor vaporising oil (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. [1] 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.[ citation needed ]
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.
| 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 |
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.
Because TVO has a lower octane rating than petrol, the engine needs a lower compression ratio. On the TVO version of the Ferguson TE20 tractor, the cylinder head was re-designed to reduce the compression ratio to 4.5:1. This reduced the power output, so the cylinder bore was increased to 85 mm to restore the power. [2] The petrol version had a compression ratio of 5.77:1 and a cylinder bore of 80 mm on early versions..
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.
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.
The phrase petrol-paraffin engine is often used to describe an engine that uses TVO. This can be interpreted either as
TVO was withdrawn from sale by UK suppliers in 1974. An approximation to the correct specification can be made from petrol and heating oil (burning oil). [4] In the UK there is an exception that permits the use of rebated kerosene and fuel oils in vintage vehicles. [5]
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]
The compression ratio is the ratio between the volume of the cylinder and combustion chamber in an internal combustion engine at their maximum and minimum values.
Kerosene, paraffin, or lamp oil is a combustible hydrocarbon liquid which is derived from petroleum. It is widely used as a fuel in aviation as well as households. Its name derives from Greek: κηρός (keros) meaning "wax", and was registered as a trademark by Canadian geologist and inventor Abraham Gesner in 1854 before evolving into a generic trademark. It is sometimes spelled kerosine in scientific and industrial usage. The term kerosene is common in much of Argentina, Australia, Canada, India, New Zealand, Nigeria, and the United States, while the term paraffin is used in Chile, eastern Africa, South Africa, Norway, and in the United Kingdom. The term lamp oil, or the equivalent in the local languages, is common in the majority of Asia and the Southeastern United States. Liquid paraffin is a more viscous and highly refined product which is used as a laxative. Paraffin wax is a waxy solid extracted from petroleum.
Gasoline or petrol is a transparent, petroleum-derived flammable liquid that is used primarily as a fuel in most spark-ignited internal combustion engines. It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives. On average, a 160-liter (42-U.S.-gallon) barrel of crude oil can yield up to about 72 liters of gasoline after processing in an oil refinery, depending on the crude oil assay and on what other refined products are also extracted. The characteristic of a particular gasoline blend to resist igniting too early is measured by its octane rating, which is produced in several grades. Tetraethyl lead and other lead compounds, once widely used to increase octane ratings, are no longer used except in aviation and off-road and auto-racing applications. Other chemicals are frequently added to gasoline to improve chemical stability and performance characteristics, control corrosiveness, and provide fuel system cleaning. Gasoline may contain oxygen-containing chemicals such as ethanol, MTBE, or ETBE to improve combustion.
Diesel fuel in general is any liquid fuel specifically designed for use in diesel engines, in which fuel ignition takes place, without any spark, as a result of compression of the inlet air mixture and then injection of fuel. Therefore, diesel fuel needs good compression ignition characteristics.
An octane rating, or octane number, is a standard measure of a fuel's ability to withstand compression in an internal combustion engine without detonating. The higher the octane number, the more compression the fuel can withstand before detonating. Octane rating does not relate directly to the power output or the energy content of the fuel per unit mass or volume, but simply indicates gasoline's capability against compression. In broad terms, fuels with a higher octane rating are used in higher-compression gasoline engines, which may yield higher power. Such higher power comes from the fuel's higher compression by the engine design, and not directly from the gasoline.
A stratified charge engine describes a certain type of internal combustion engine, usually spark ignition (SI) engine that can be used in trucks, automobiles, portable and stationary equipment. The term "stratified charge" refers to the working fluids and fuel vapors entering the cylinder. Usually the fuel is injected into the cylinder or enters as a fuel rich vapor where a spark or other means are used to initiate ignition where the fuel rich zone interacts with the air to promote complete combustion. A stratified charge can allow for slightly higher compression ratios without "knock," and leaner air/fuel ratio than in conventional internal combustion engines.
A petrol engine or gasoline engine is an internal combustion engine with spark-ignition, designed to run on petrol (gasoline) and similar volatile fuels.
TVO may refer to:
Natural-gas condensate, also called natural gas liquids, is a low-density mixture of hydrocarbon liquids that are present as gaseous components in the raw natural gas produced from many natural gas fields. Some gas species within the raw natural gas will condense to a liquid state if the temperature is reduced to below the hydrocarbon dew point temperature at a set pressure.
Liquid fuels are combustible or energy-generating molecules that can be harnessed to create mechanical energy, usually producing kinetic energy; they also must take the shape of their container. It is the fumes of liquid fuels that are flammable instead of the fluid. Most liquid fuels in widespread use are derived from fossil fuels; however, there are several types, such as hydrogen fuel, ethanol, and biodiesel, which are also categorized as a liquid fuel. Many liquid fuels play a primary role in transportation and the economy.
Herbert Akroyd-Stuart was an English inventor who is noted for his invention of the hot bulb engine, or heavy oil engine.
The Ferguson TE20 is an agricultural tractor designed by Harry Ferguson. By far his most successful design, it was manufactured from 1946 until 1956, and was commonly known as the Little Grey Fergie. It marked a major advance in tractor design, distinguished by lightweight, small size, manoeuvrability and versatility. The TE20 popularised Harry Ferguson's invention of the hydraulic three-point hitch system around the world, and the system quickly became an international standard for tractors of all makes and sizes that has remained to this day. The tractor played a large part in introducing widespread mechanised agriculture. In many parts of the world the TE20 was the first tractor to be affordable to the average farmer and was small and light enough to replace the draft horse and manual labour. Many TE20s remain in regular use in farming and other work and the model is also a popular collector's item for enthusiasts today.
The hot-bulb engine is a type of internal combustion engine in which fuel ignites by coming in contact with a red-hot metal surface inside a bulb, followed by the introduction of air (oxygen) compressed into the hot-bulb chamber by the rising piston. There is some ignition when the fuel is introduced, but it quickly uses up the available oxygen in the bulb. Vigorous ignition takes place only when sufficient oxygen is supplied to the hot-bulb chamber on the compression stroke of the engine.
A petcock is a small shut-off valve used to control the flow of liquid or gas. Historically, petcocks were threaded valves controlled by a butterfly handle; modern petcocks are typically ball valves.
Engine efficiency of thermal engines is the relationship between the total energy contained in the fuel, and the amount of energy used to perform useful work. There are two classifications of thermal engines-
Paraffin may refer to:
The Standard wet liner inline-four engine was a 2,088 cc inline four cylinder petrol engine produced by the Standard Motor Company. Originally developed concurrently for passenger car use and for the Ferguson TE20 tractor, it was widely used for Standard passenger cars of the 1950s, most notably the Vanguard. Later it was successfully used in Standard's popular early generation Triumph TR series sports cars.
Petroleum refining processes are the chemical engineering processes and other facilities used in petroleum refineries to transform crude oil into useful products such as liquefied petroleum gas (LPG), gasoline or petrol, kerosene, jet fuel, diesel oil and fuel oils.
A petrol-paraffin engine, TVO engine or gasoline-kerosene engine is an old-fashioned type of dual-fuel internal combustion engine with spark-ignition, designed to start on petrol (gasoline) and then to switch to run on paraffin (kerosene) once the engine is warm. The grade of paraffin used is known as tractor vaporising oil in the UK.
Distillate fuel, also called tractor fuel, was a petroleum product that was commonly used to power North American agricultural tractors in the early and mid-twentieth century. The product was crudely refined, akin to kerosene chemically, but impure.
