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A petrol-paraffin engine, TVO engine (United Kingdom) or gasoline-kerosene engine (North America) 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.
The advantages of the petrol-paraffin engine are that (compared to petrol):
Some of these advantages have become illusory since paraffin, once widely available as a cheap fuel, has become rarer and more expensive, particularly in developed countries. Also, while some older vessels still use marine petrol-paraffin engines, most inboard marine engines now tend to be diesels.[ citation needed ]
A petrol-paraffin engine differs from a single-fuel petrol engine in that two independent fuel tanks containing petrol and paraffin (respectively) are required, but both fuels may be supplied through the same carburetor or fuel injection system. An example of a fuel-injected petrol-paraffin engine is the Hesselman engine. [2]
Paraffin is less volatile than petrol, and will not normally ignite at ambient temperatures, so the petrol-paraffin engine is started using petrol, and only when the engine has attained a sufficient operating temperature will the engine be switched to paraffin. This switching can be done manually or automatically. Some engines use a vaporizer, which uses heat from the exhaust manifold to vaporize the fuel entering the intake system.[ citation needed ]
Petrol-paraffin engines were traditionally found in motor boats, fishing vessels, small tractors, light railway locomotives, and stationary auxiliary engines, [3] [4] [5] but not in cars or motorcycles.
The Milnes-Daimler motor bus of 1904 (based on the Cannstatt Daimler lorry), operated in London by Thomas Tilling, ran on either petrol or paraffin, but for starting the engine, or frequent stop-start work, petrol continuously was the preferable option. The airflow from the carburettor was heated by diverted exhaust gas. [6]
Petrol-paraffin fuelling is suitable for four-stroke cycle piston engines and wankel engines. A petrol/paraffin engine tends to run hotter whilst burning paraffin, and so the cooling system must be sufficiently robust. Being slower burning, the paraffin requires the longer combustion period that a four-stroke engine can provide; so two-stroke versions are rare J.A.P. used their 16H engine on TVO.[ citation needed ] Although modern petrol engines may have compression ratios typically between 9:1 and 12:1, a petrol-paraffin engine requires a lower compression ratio of 8:1 or less, to avoid pre-ignition of the fuel-air mixture which would cause damage from engine knocking. Most existing petrol aero-engines have low compression ratios, around 8:1 or 9:1, making dual-fuel conversions viable.[ citation needed ]
The fuel used in petrol-paraffin engines was known as Tractor vaporising oil (TVO) in the United Kingdom and as Power kerosene in Australia. TVO was withdrawn from sale by UK suppliers in 1974 but has been re-introduced by at least one supplier. [7]
A railway locomotive using solid naphthalene was built by Schneider-Creusot in France in 1913. It was a 70 bhp petrol-paraffin engine, but using solid naphthalene rather than paraffin, simply as a cheaper fuel. The naphthalene was melted and vaporised by a water jacket, heated by the engine. [8]
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.
The diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is called a compression-ignition engine. This contrasts with engines using spark plug-ignition of the air-fuel mixture, such as a petrol engine or a gas engine.
A carburetor is a device used by a gasoline internal combustion engine to control and mix air and fuel entering the engine. The primary method of adding fuel to the intake air is through the Venturi tube in the main metering circuit, though various other components are also used to provide extra fuel or air in specific circumstances.
Diesel fuel, also called diesel oil or historically heavy oil, is any liquid fuel specifically designed for use in a diesel engine, a type of internal combustion engine in which fuel ignition takes place without a spark as a result of compression of the inlet air and then injection of fuel. Therefore, diesel fuel needs good compression ignition characteristics.
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 is an internal combustion engine designed to run on petrol (gasoline). Petrol engines can often be adapted to also run on fuels such as liquefied petroleum gas and ethanol blends.
A four-strokeengine is an internal combustion (IC) engine in which the piston completes four separate strokes while turning the crankshaft. A stroke refers to the full travel of the piston along the cylinder, in either direction. The four separate strokes are termed:
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.
Indirect injection in an internal combustion engine is fuel injection where fuel is not directly injected into the combustion chamber.
The Otto engine was a large stationary single-cylinder internal combustion four-stroke engine designed by the German Nicolaus Otto. It was a low-RPM machine, and only fired every other stroke due to the Otto cycle, also designed by Otto.
Tractor vaporising oil (TVO) is a fuel for petrol-paraffin engines. It is seldom made or used today. In the United Kingdom and Australia, after the Second World War, it was commonly used for tractors until diesel engines became commonplace, especially from the 1960s onward. In Australian English it was known as power kerosene.
The hot-bulb engine, also known as a semi-diesel, 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.
The Hornsby-Akroyd oil engine, named after its inventor Herbert Akroyd Stuart and the manufacturer Richard Hornsby & Sons, was the first successful design of an internal combustion engine using heavy oil as a fuel. It was the first to use a separate vapourising combustion chamber and is the forerunner of all hot-bulb engines, which are considered predecessors of the similar Diesel engine, developed a few years later.
A carbureted compression ignition model engine, popularly known as a model diesel engine, is a simple compression ignition engine made for model propulsion, usually model aircraft but also model boats. These are quite similar to the typical glow-plug engine that runs on a mixture of methanol-based fuels with a hot wire filament to provide ignition. Despite their name, their use of compression ignition, and the use of a kerosene fuel that is similar to diesel, model diesels share very little with full-size diesel engines.
A naphtha launch, sometimes called a "vapor launch", was a small motor launch, powered by a naphtha engine. They were a particularly American design, brought into being by a local law that made it impractical to use a steam launch for private use.
The Hesselman engine is a hybrid between a petrol engine and a diesel engine. It was designed and introduced in 1925 by Swedish engineer Jonas Hesselman.
The Standard wet liner inline-four engine was an 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.
An internal combustion engine is a heat engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combustion engine, the expansion of the high-temperature and high-pressure gases produced by combustion applies direct force to some component of the engine. The force is typically applied to pistons, turbine blades, a rotor, or a nozzle. This force moves the component over a distance, transforming chemical energy into kinetic energy which is used to propel, move or power whatever the engine is attached to.
Distillate fuel, also called tractor fuel, was a petroleum product that was commonly used to power North American agricultural tractors from the early and mid-20th century. The product was crudely refined, akin to kerosene chemically, but impure.