Watt steam engineThe Watt steam engine design became synonymous with steam engines, and it was many years before significantly new designs began to replace the basic Watt design. The first steam engines, introduced by Thomas Newcomen in 1712, were of the "atmospheric" design. At the end of the power stroke, the weight of the object being moved by the engine pulled the piston to the top of the cylinder as steam was introduced. Then the cylinder was cooled by a spray of water, which caused the steam to condense, forming a partial vacuum in the cylinder.
External combustion engineAn external combustion engine (EC engine) is a reciprocating heat engine where a working fluid, contained internally, is heated by combustion in an external source, through the engine wall or a heat exchanger. The fluid then, by expanding and acting on the mechanism of the engine, produces motion and usable work. The fluid is then dumped (open cycle), or cooled, compressed and reused (closed cycle). In these types of engines, the combustion is primarily used as a heat source, and the engine can work equally well with other types of heat sources.
Reciprocating motionReciprocating motion, also called reciprocation, is a repetitive up-and-down or back-and-forth linear motion. It is found in a wide range of mechanisms, including reciprocating engines and pumps. The two opposite motions that comprise a single reciprocation cycle are called strokes. A crank can be used to convert into reciprocating motion, or conversely turn reciprocating motion into circular motion.
Fuel injectionFuel injection is the introduction of fuel in an internal combustion engine, most commonly automotive engines, by the means of an injector. This article focuses on fuel injection in reciprocating piston and Wankel rotary engines. All compression-ignition engines (e.g. diesel engines), and many spark-ignition engines (i.e. petrol (gasoline) engines, such as Otto or Wankel), use fuel injection of one kind or another.
Straight engineThe straight engine (also called inline engine) is a piston engine where all of the cylinders are aligned in a row along the crankshaft. Most straight engines have four or six cylinders, however straight engines have ranged from two cylinders to fourteen cylinders. A straight engine is easier to build than an equivalent flat engine or V engine, since it uses one cylinder head rather than two. Inline engines are also narrower than flat engines or V engines, however they are longer and can be taller.
Opposed-piston engineAn opposed-piston engine is a piston engine in which each cylinder has a piston at both ends, and no cylinder head. Petrol and diesel opposed-piston engines have been used mostly in large-scale applications such as ships, military tanks, and factories. Current manufacturers of opposed-piston engines include Cummins, Achates Power and Fairbanks-Morse Defense (FMDefense).
Rotary engineThe rotary engine is an early type of internal combustion engine, usually designed with an odd number of cylinders per row in a radial configuration. The engine's crankshaft remained stationary in operation, while the entire crankcase and its attached cylinders rotated around it as a unit. Its main application was in aviation, although it also saw use in a few early motorcycles and automobiles. This type of engine was widely used as an alternative to conventional inline engines (straight or V) during World War I and the years immediately preceding that conflict.
Ignition systemIgnition systems are used by heat engines to initiate combustion by igniting the fuel-air mixture. In a spark ignition versions of the internal combustion engine (such as petrol engines), the ignition system creates a spark to ignite the fuel-air mixture just before each combustion stroke. Gas turbine engines and rocket engines normally use an ignition system only during start-up. Diesel engines use compression ignition to ignite the fuel-air mixture using the heat of compression and therefore do not use an ignition system.
SwashplateA swashplate, also known as slant disk, is a mechanical engineering device used to translate the motion of a rotating shaft into reciprocating motion, or vice versa. The working principle is similar to crankshaft, Scotch yoke, or wobble/nutator/Z-crank drives, in engine designs. It was originally invented to replace a crankshaft, and is one of the most popular concepts used in crankless engines. It was invented by Anthony Michell in 1917. A swashplate consists of a disk attached to a shaft.
Single- and double-acting cylindersIn mechanical engineering, the cylinders of reciprocating engines are often classified by whether they are single- or double-acting, depending on how the working fluid acts on the piston. A single-acting cylinder in a reciprocating engine is a cylinder in which the working fluid acts on one side of the piston only. A single-acting cylinder relies on the load, springs, other cylinders, or the momentum of a flywheel, to push the piston back in the other direction. Single-acting cylinders are found in most kinds of reciprocating engine.
