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mechanical engineering Mechanical engineering is the study of physical machines that may involve force and movement. It is an engineering branch that combines engineering physics and mathematics principles with materials science, to design, analyze, manufacture, an ...
, the cylinders of
reciprocating engine 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 fea ...
s are often classified by whether they are single- or double-acting, depending on how the
working fluid For fluid power, a working fluid is a gas or liquid that primarily transfers force, motion, or mechanical energy. In hydraulics, water or hydraulic fluid transfers force between hydraulic components such as hydraulic pumps, hydraulic cylinders, ...
acts on the piston.


Single-acting

A single-acting cylinder in a
reciprocating engine 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 fea ...
is a
cylinder A cylinder (from ) has traditionally been a three-dimensional solid, one of the most basic of curvilinear geometric shapes. In elementary geometry, it is considered a prism with a circle as its base. A cylinder may also be defined as an infin ...
in which the
working fluid For fluid power, a working fluid is a gas or liquid that primarily transfers force, motion, or mechanical energy. In hydraulics, water or hydraulic fluid transfers force between hydraulic components such as hydraulic pumps, hydraulic cylinders, ...
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 A flywheel is a mechanical device which uses the conservation of angular momentum to store rotational energy; a form of kinetic energy proportional to the product of its moment of inertia and the square of its rotational speed. In particular, as ...
, to push the piston back in the other direction. Single-acting cylinders are found in most kinds of reciprocating engine. They are almost universal in
internal combustion engine An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal c ...
s (e.g.
petrol Gasoline (; ) or petrol (; ) (see ) is a transparent, petroleum-derived flammable liquid that is used primarily as a fuel in most spark-ignited internal combustion engines (also known as petrol engines). It consists mostly of organic c ...
and
diesel engine 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 a so-ca ...
s) and are also used in many
external combustion engine An 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 an ...
s such as
Stirling engine A Stirling engine is a heat engine that is operated by the cyclic compression and expansion of air or other gas (the ''working fluid'') between different temperatures, resulting in a net conversion of heat energy to mechanical work. More specif ...
s and some steam engines. They are also found in pumps and
hydraulic ram A hydraulic ram, or hydram, is a cyclic water pump powered by hydropower. It takes in water at one "hydraulic head" (pressure) and flow rate, and outputs water at a higher hydraulic head and lower flow rate. The device uses the water hammer ef ...
s.


Double-acting

A double-acting cylinder is a cylinder in which the working fluid acts alternately on both sides of the piston. In order to connect the piston in a double-acting cylinder to an external mechanism, such as a crank shaft, a hole must be provided in one end of the cylinder for the piston rod, and this is fitted with a gland or "
stuffing box A stuffing box or gland package is an assembly which is used to house a gland seal. It is used to prevent leakage of fluid, such as water or steam, between sliding or turning parts of machine elements. Components A stuffing box of a sailing boat ...
" to prevent escape of the working fluid. Double-acting cylinders are common in steam engines but unusual in other engine types. Many hydraulic and pneumatic cylinders use them where it is needed to produce a force in both directions. A double-acting hydraulic cylinder has a port at each end, supplied with hydraulic fluid for both the retraction and extension of the piston. A double-acting cylinder is used where an external force is not available to retract the piston or it can be used where high force is required in both directions of travel.


Steam engines

Single-acting oscillating-cylinder steam engine Steam engines normally use double-acting cylinders. However, early steam engines, such as atmospheric engines and some beam engines, were single-acting. These often transmitted their force through the beam by means of chains and an "arch head", as only a tension in one direction was needed. Where these were used for pumping mine shafts and only had to act against a load in one direction, single-acting designs remained in use for many years. The main impetus towards double-acting cylinders came when James Watt was trying to develop a
rotative beam engine A beam engine is a type of steam engine where a pivoted overhead beam is used to apply the force from a vertical piston to a vertical connecting rod. This configuration, with the engine directly driving a pump, was first used by Thomas Newc ...
, that could be used to drive machinery via an output shaft. With a single-cylinder engine, a double-acting cylinder gave a smoother power output. The high-pressure engine, as developed by
Richard Trevithick Richard Trevithick (13 April 1771 – 22 April 1833) was a British inventor and mining engineer. The son of a mining captain, and born in the mining heartland of Cornwall, Trevithick was immersed in mining and engineering from an early age. He w ...
, used double-acting pistons and became the model for most steam engines afterwards. Some of the later steam engines, the
high-speed steam engine High-speed steam engines were one of the final developments of the stationary steam engine. They ran at a high speed, of several hundred rpm,, 400 to 1,200 rpm which was needed by tasks such as electricity generation. Defining characteristics ...
s, used single-acting pistons of a new design. The crosshead became part of the piston, and there was no longer any piston rod. This was for similar reasons to the internal combustion engine, as avoiding the piston rod and its seals allowed a more effective crankcase lubrication system. Small models and toys often use single-acting cylinders for the above reason but also to reduce manufacturing costs.


Internal combustion engines

In contrast to steam engines, nearly all
internal combustion engine An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal c ...
s have used single-acting cylinders. Their pistons are usually
trunk piston A piston is a component of reciprocating engines, reciprocating pumps, gas compressors, hydraulic cylinders and pneumatic cylinders, among other similar mechanisms. It is the moving component that is contained by a cylinder and is made gas-tigh ...
s, where the gudgeon pin joint of the connecting rod is within the piston itself. This avoids the crosshead, piston rod and its sealing gland, but it also makes a single-acting piston almost essential. This, in turn, has the advantage of allowing easy access to the bottom of the piston for lubricating oil, which also has an important cooling function. This avoids local overheating of the piston and rings.


Crankcase compression two-stroke engines

Small petrol
two-stroke engine A two-stroke (or two-stroke cycle) engine is a type of internal combustion engine that completes a power cycle with two strokes (up and down movements) of the piston during one power cycle, this power cycle being completed in one revolution of ...
s, such as for motorcycles, use crankcase compression rather than a separate supercharger or
scavenge blower 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 a so-calle ...
. This uses both sides of the piston as working faces, the lower side of the piston acting as a piston compressor to compress the inlet charge ready for the next stroke. The piston is still considered as single-acting, as only one of these faces ''produces'' power.


Double-acting internal combustion engines

Some early gas engines, such as
Lenoir Lenoir may refer to: Locations: * Lenoir, North Carolina, United States * Lenoir County, North Carolina, United States * Lenoir City, Tennessee In Universities: * Lenoir-Rhyne University * Lenoir Dining Hall, a dining hall at the University of N ...
's original engines, from around 1860, were double-acting and followed steam engines in their design. Internal combustion engines soon switched to single-acting cylinders. This was for two reasons: as for the high-speed steam engine, the high force on each piston and its connecting rod was so great that it placed large demands upon the bearings. A single-acting piston, where the direction of the forces was consistently compressive along the connecting rod, allowed for tighter bearing clearances. Secondly the need for large valve areas to provide good gas flow, whilst requiring a small volume for the combustion chamber so as to provide good
compression Compression may refer to: Physical science *Compression (physics), size reduction due to forces *Compression member, a structural element such as a column *Compressibility, susceptibility to compression * Gas compression *Compression ratio, of a ...
, monopolised the space available in the
cylinder head In an internal combustion engine, the cylinder head (often abbreviated to simply "head") sits above the cylinders and forms the roof of the combustion chamber. In sidevalve engines, the head is a simple sheet of metal; whereas in more modern ...
. Lenoir's steam engine-derived cylinder was inadequate for the
petrol engine A petrol engine (gasoline engine in American English) 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 (such as ' ...
and so a new design, based around
poppet valve A poppet valve (also called mushroom valve) is a valve typically used to control the timing and quantity of gas or vapor flow into an engine. It consists of a hole or open-ended chamber, usually round or oval in cross-section, and a plug, usua ...
s and a single-acting
trunk piston A piston is a component of reciprocating engines, reciprocating pumps, gas compressors, hydraulic cylinders and pneumatic cylinders, among other similar mechanisms. It is the moving component that is contained by a cylinder and is made gas-tigh ...
appeared instead. Extremely large gas engines were also built as
blowing engine A blowing engine is a large stationary steam engine or internal combustion engine directly coupled to air pumping cylinders. They deliver a very large quantity of air at a pressure lower than an air compressor, but greater than a centrifugal fan. ...
s for blast furnaces, with one or two extremely large cylinders and powered by the burning of furnace gas. These, particularly those built by
Körting Körting is a surname. Notable people with the name include: * Georg Körting (1844–1919), German Chief Surgeon General of the Guards Corps in the First World War * Gustav Körting (1845–1913), German philologist * Heinrich Körting (1859–189 ...
, used double-acting cylinders. Gas engines require little or no compression of their charge, in comparison to petrol or compression-ignition engines, and so the double-acting cylinder designs were still adequate, despite their narrow, convoluted passageways. Double-acting cylinders have been infrequently used for internal combustion engines since, although
Burmeister & Wain Burmeister & Wain was a large established Danish shipyard and leading diesel engine producer headquartered in Copenhagen, Denmark. Founded by two Danes and an Englishman, its earliest roots stretch back to 1846. Over its 150-year history, it ...
made 2-stroke cycle double-acting (2-SCDA) diesels for marine propulsion before 1930. The first, of 7,000 hp, was fitted in the British MV ''Amerika'' (United Baltic Co.) in 1929."Amazing Airplane Motor Doubles The Power", Popular Mechanics, September 1932
cutaway drawing of double action aircraft engine The two B&W SCDA engines fitted to the in 1937 produced 24,000 hp each.


USS ''Pompano''

In 1935 the US submarine USS ''Pompano'' was ordered as part of the ''Perch'' class Six boats were built, with three different diesel engine designs from different makers. ''Pompano'' was fitted with H.O.R. (
Hooven-Owens-Rentschler The firm of Hooven, Owens, Rentschler, and Company manufactured steam and diesel engines in Hamilton, Ohio. Because the firm was frequently known by its initials, H.O.R., the ''Hooven'' is sometimes incorrectly rendered as ''Hoover'', and the '' ...
) 8-cylinder double-acting engines that were a
licence-built Licensed production is the production under license of technology developed elsewhere. The licensee provides the licensor of a specific product with legal production rights, technical information, process technology, and any other proprietary compo ...
version of the
MAN A man is an adult male human. Prior to adulthood, a male human is referred to as a boy (a male child or adolescent). Like most other male mammals, a man's genome usually inherits an X chromosome from the mother and a Y chromo ...
auxiliary engines of the cruiser ''Leipzig''. Owing to the limited space available within the submarines, either
opposed-piston An 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 f ...
, or, in this case, double-acting engines were favoured for being more compact. ''Pompano''s engines were a complete failure and were wrecked during trials before even leaving the
Mare Island Navy Yard The Mare Island Naval Shipyard (MINSY) was the first United States Navy base established on the Pacific Ocean. It is located northeast of San Francisco in Vallejo, California. The Napa River goes through the Mare Island Strait and separates t ...
. ''Pompano'' was laid up for eight months until 1938 while the engines were replaced. Even then the engines were regarded as unsatisfactory and were replaced by
Fairbanks-Morse Fairbanks, Morse and Company was an American manufacturing company in the late 19th and early 20th century. Originally a weighing scale manufacturer, it later diversified into pumps, engines, windmills, coffee grinders, radios, farm tractors, fee ...
engines in 1942. While ''Pompano'' was still being built, the ''Salmon''-class submarines were ordered. Three of these were built by Electric Boat, with a 9-cylinder development of the H.O.R. engine. Although not as great a failure as ''Pompano''s engines, this version was still troublesome and the boats were later re-engined with the same single-acting General Motors 16-248 V16 engines as their sister boats. Other Electric Boat-constructed submarines of the ''Sargo'' and ''Seadragon'' classes, as well as the first few of the ''Gato'' class, were also built with these 9-cylinder H.O.R. engines, but later re-engined.


Hydraulic cylinders

A hydraulic cylinder is a mechanical actuator that is powered by a pressurised liquid, typically oil. It has many applications, notably in construction equipment (
engineering vehicles Heavy equipment or heavy machinery refers to heavy-duty vehicles specially designed to execute construction tasks, most frequently involving earthwork operations or other large construction tasks. ''Heavy equipment'' usually comprises five e ...
), manufacturing machinery, and civil engineering.


Footnotes


References

{{Steam engine configurations, state=collapsed Piston engines Steam engines Hydraulics