page_title: Hot-bulb engine
section_title: Uses
hierarchical_section_title: Hot-bulb engine / Uses
caption_attribution_description: Deutsch: Lanz Bulldog der Baureihe D 8506, Baujahr 1939 (Bauzeit 1936 bis 1954), Einzylinder-Glühkopfmotor, Hubraum 10.338 cm³, 35 PS, aufgenommen am 15.07.2006 beim Traktortreffen in Hillscheid.
context_page_description: 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 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.
  Most hot-bulb engines were produced as one or two-cylinder, low-speed two-stroke crankcase scavenged units.
context_section_description: The reliability of the hot bulb engine, their ability to run on many fuels and the fact that they can be left running for hours or days at a time made them extremely popular with agricultural, forestry and marine users, where they were used for pumping and for powering milling, sawing and threshing machinery. Hot bulb engines were also used on road rollers and tractors.
  J.V. Svenssons Motorfabrik, i Augustendal in Stockholm Sweden used hot bulb engines in their Typ 1 motor plough, produced from 1912 to 1925. Munktells Mekaniska Verkstads AB, in Eskilstuna, Sweden, produced agricultural tractors with hot bulb engines from 1913 onwards.  Heinrich Lanz AG, in Mannheim, Germany, started to use hot bulb engines in 1921, in the Lanz Bulldog HL tractor. Other well known tractor manufacturers that used bulb engines were Bubba, Gambino, Landini and Orsi in Italy, HSCS in Hungary, SFV in France, and Ursus in Poland.
  At the start of the 20th century there were several hundred European manufacturers of hot bulb engines for marine use. In Sweden alone there were over 70 manufacturers, of which Bolinder is the best known; in the 1920s they had about 80% of the world market. The Norwegian Sabb was a very popular hot bulb engine for small fishing boats, and many of them are still in working order.  In America, Standard, Weber, Reid, Stickney, Oil City, and Fairbanks Morse built hot bulb engines.
  A limitation of the design of the engine was that it could only run over quite a narrow (and slow) speed band, typically 50 to 300 rpm.  This made the hot bulb engine difficult to adapt to automotive uses, other than vehicles such as tractors, where speed was not a major requirement. This limitation was of little consequence for stationary applications, where the hot bulb engine was very popular.
  Owing to the lengthy pre-heating time, hot bulb engines only found favour with users who needed to run engines for long periods of time, where the pre-heating process only represented a small percentage of the overall running period. This included marine use — especially in fishing boats — and pumping or drainage duties.
  The hot bulb engine was invented at the same time that dynamos and electric light systems were perfected, and electricity generation was one of the hot bulb engine's main uses. The engine could achieve higher R.P.M. than a standard reciprocating steam engine, although high-speed steam engines were developed during the 1890s, and its low fuel and maintenance requirements, including the ability to be operated and maintained by only one person, made it ideal for small-scale power generation. Generator sets driven by hot bulb engines were installed in numerous large houses in Europe, especially in rural areas, as well as in factories, theatres, lighthouses, radio stations and many other locations where a centralised electrical grid was not available. Usually, the dynamo or alternator would be driven off the engine's flywheel by a flat belt, to allow the necessary "gearing up" — making the generator turn at a faster speed than the engine. Companies such as Armstrong Whitworth and Boulton Paul manufactured and supplied complete generating sets, both the engine and generator, from the 1900s to the late 1920s, when the formation of national grid systems throughout the world and the replacement of the hot bulb engine by the diesel engine caused a drop in demand.
  The engines were also used in areas where the fire of a steam engine would be an unacceptable fire risk. Akroyd-Stuart developed the world's first locomotive powered by a hot bulb oil engine, the "Lachesis", for the Royal Arsenal, Woolwich, where the use of locomotives had previously been impossible due to the risk. Hot bulb engines proved very popular for industrial engines in the early 20th century, but lacked the power to be used in anything larger.
caption: 1939 Lanz Bulldog, a tractor built around a hot bulb engine.
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