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Engines

In the early to mid-20th century, kerosene or tractor vaporizing oil (TVO) was used as a cheap fuel for tractors and hit 'n miss engines. The engine would start on gasoline, then switch over to kerosene once the engine warmed up. On some engines a heat valve on the manifold would route the exhaust gasses around the intake pipe, heating the kerosene to the point where it was vaporized and could be ignited by an electric spark.

In Europe following the Second World War, automobiles were similarly modified to run on kerosene rather than gasoline, which they would have to import and pay heavy taxes on. Besides additional piping and the switch between fuels, the head gasket was replaced by a much thicker one to diminish the compression ratio (making the engine less powerful and less efficient, but able to run on kerosene). The necessary equipment was sold under the trademark "Econom".

During the fuel crisis of the 1970s, Saab-Valmet developed and series-produced the Saab 99 Petro that ran on kerosene, turpentine or gasoline. The project, codenamed "Project Lapponia", was headed by Simo Vuorio, and towards the end of the 1970s, a working prototype was produced based on the Saab 99 GL. The car was designed to run on two fuels. Gasoline was used for cold starts and when extra power was needed, but normally it ran on kerosene or turpentine. The idea was that the gasoline could be made from peat using the Fischer–Tropsch process. Between 1980 and 1984, 3,756 Saab 99 Petros and 2,385 Talbot Horizons (a version of the Chrysler Horizon that integrated many Saab components) were made. One reason to manufacture kerosene-fueled cars was that in Finland kerosene was less heavily taxed than gasoline.

Kerosene is used to fuel smaller-horsepower outboard motors built by Yamaha, Suzuki, and Tohatsu. Primarily used on small fishing craft, these are dual-fuel engines that start on gasoline and then transition to kerosene once the engine reaches optimum operating temperature. Multiple fuel Evinrude and Mercury Racing engines also burn kerosene, as well as jet fuel.

Today, kerosene is mainly used in fuel for jet engines in several grades. One highly refined form of the fuel is known as RP-1, and is often burned with liquid oxygen as rocket fuel. These fuel grade kerosenes meet specifications for smoke points and freeze points. The combustion reaction can be approximated as follows, with the molecular formula C H (dodecane):

In the initial phase of liftoff, the Saturn V launch vehicle was powered by the reaction of liquid oxygen with RP-1. For the five 6.4 meganewton sea-level thrust F-1 rocket engines of the Saturn V, burning together, the reaction generated roughly 1.62 × 10 watts (J/s) (162 gigawatt) or 217 million horsepower.

Kerosene is sometimes used as an additive in diesel fuel to prevent gelling or waxing in cold temperatures.

Ultra-low sulfur kerosene is a custom-blended fuel used by the New York City Transit Authority to power its bus fleet. The transit agency started using this fuel in 2004, prior to the widespread adoption of ultra-low-sulfur diesel, which has since become the standard. In 2008, the suppliers of the custom fuel failed to tender for a renewal of the transit agency's contract, leading to a negotiated contract at a significantly increased cost.

JP-8 (for "Jet Propellant 8"), a kerosene-based fuel, is used by the United States military as a replacement in diesel fueled vehicles and for powering aircraft. JP-8 is also used by the U.S. military and its NATO allies as a fuel for heaters, stoves, tanks, and as a replacement for diesel fuel in the engines of nearly all tactical ground vehicles and electrical generators.