A reciprocating engine, also often known as a piston engine, is typically a heat engine that uses one or more reciprocating pistons to convert high temperature and high pressure into a rotating motion. This article describes the common features of all types. The main types are: the internal combustion engine, used extensively in motor vehicles; the steam engine, the mainstay of the Industrial Revolution; and the Stirling engine for niche applications. Internal combustion engines are further classified in two ways: either a spark-ignition (SI) engine, where the spark plug initiates the combustion; or a compression-ignition (CI) engine, where the air within the cylinder is compressed, thus heating it, so that the heated air ignites fuel that is injected then or earlier.
A steam engine is a heat engine that performs mechanical work using steam as its working fluid. The steam engine uses the force produced by steam pressure to push a piston back and forth inside a cylinder. This pushing force can be transformed, by a connecting rod and crank, into rotational force for work. The term "steam engine" is most commonly applied to reciprocating engines as just described, although some authorities have also referred to the steam turbine and devices such as Hero's aeolipile as "steam engines". The essential feature of steam engines is that they are external combustion engines, where the working fluid is separated from the combustion products. The ideal thermodynamic cycle used to analyze this process is called the Rankine cycle. In general usage, the term steam engine can refer to either complete steam plants, such as railway steam locomotives and portable engines, or may refer to the piston or turbine machinery alone, as in the beam engine and stationary steam engine.
The valve gear of a steam engine is the mechanism that operates the inlet and exhaust valves to admit steam into the cylinder and allow exhaust steam to escape, respectively, at the correct points in the cycle. It can also serve as a reversing gear. It is sometimes referred to as the "motion".
A connecting rod, also called a 'con rod', is the part of a piston engine which connects the piston to the crankshaft. Together with the crank, the connecting rod converts the reciprocating motion of the piston into the rotation of the crankshaft. The connecting rod is required to transmit the compressive and tensile forces from the piston. In its most common form, in an internal combustion engine, it allows pivoting on the piston end and rotation on the shaft end.
Main components found on a typical steam locomotive include:
A fire-tube boiler is a type of boiler invented in 1828 by Mark Seguin, in which hot gases pass from a fire through one or more tubes running through a sealed container of water. The heat of the gases is transferred through the walls of the tubes by thermal conduction, heating the water and ultimately creating steam.
Mamod is a toy manufacturer based in Britain that specializes in producing live steam models. The company was founded in Birmingham in 1937 by Geoffrey Malins. The name "Mamod" is a combination of "Malins Models." Initially, the company manufactured stationary steam engines, which were originally sold under the 'Hobbies' brand. Subsequently, Malins introduced the brand name 'Mamod.' Over time, Mamod expanded its range to include models of road rollers, traction engines, steam wagons, and other steam-powered road vehicles. These models were primarily intended for the toy market and were designed to be user-friendly and operate at low boiler pressures for safety, although they were not precise scale models.
A portable engine is an engine, either a steam engine or an internal combustion engine, that sits in one place while operating, but is portable and thus can be easily moved from one work site to another. Mounted on wheels or skids, it is either towed to the work site or moves there via self-propulsion.
A hit-and-miss engine or Hit 'N' Miss is a type of stationary internal combustion engine that is controlled by a governor to only fire at a set speed. They are usually 4-stroke but 2-stroke versions were made. It was conceived in the late 19th century and produced by various companies from the 1890s through approximately the 1940s. The name comes from the speed control on these engines: they fire ("hit") only when operating at or below a set speed, and cycle without firing ("miss") when they exceed their set speed. This is as compared to the "throttle governed" method of speed control. The sound made when the engine is running without a load is a distinctive "Snort POP whoosh whoosh whoosh whoosh snort POP" as the engine fires and then coasts until the speed decreases and it fires again to maintain its average speed. The snorting is caused by the atmospheric intake valve used on many of these engines.
The Leavitt-Riedler Pumping Engine (1894) is a historic steam engine located in the former Chestnut Hill High Service Pumping Station, in Boston, Massachusetts. It has been declared a historic mechanical engineering landmark by the American Society of Mechanical Engineers. The pumping station was decommissioned in the 1970s, and turned into the Metropolitan Waterworks Museum in 2011.
The London Steam Carriage was an early steam-powered road vehicle constructed by Richard Trevithick in 1803 and the world's first self-propelled passenger-carrying vehicle. Cugnot had built a steam vehicle 30 years previously, but that had been a slow-moving artillery tractor, not built to carry passengers.
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.
An oscillating cylinder steam engine is a simple steam-engine design that requires no valve gear. Instead the cylinder rocks, or oscillates, as the crank moves the piston, pivoting in the mounting trunnion so that ports in the cylinder line up with ports in a fixed port face alternately to direct steam into or out of the cylinder.
Internal combustion engines come in a wide variety of types, but have certain family resemblances, and thus share many common types of components.
The South African Railways Class 10B 4-6-2 of 1910 was a steam locomotive from the pre-Union era in Transvaal.
The South African Railways Class 10A 4-6-2 of 1910 was a steam locomotive from the pre-Union era in Transvaal.
The South African Railways Class 6L 4-6-0 of 1904 was a steam locomotive from the pre-Union era in the Cape of Good Hope.
A semi-portable engine is a form of stationary steam engine. They were built in a factory as a single unit including the boiler, so that they could be rapidly installed on site and brought into service.
A return connecting rod, return piston rod or double piston rod engine or back-acting engine is a particular layout for a steam engine.
Stuart Turner Ltd is a British engineering company, based in Henley-on-Thames, Oxfordshire, England, founded by engineer Sidney Marmaduke Stuart Turner in 1906.
