The split-cycle engine is a type of

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 combus ...

Design

In a conventional

Otto cycle An Otto cycle is an idealized thermodynamic cycle that describes the functioning of a typical spark ignition piston engine. It is the thermodynamic cycle most commonly found in automobile engines. The Otto cycle is a description of what happ ...

engine, each

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 ...

performs four strokes per cycle: intake, compression, power, and exhaust. This means that two revolutions of the

crankshaft A crankshaft is a mechanical component used in a piston engine to convert the reciprocating motion into rotational motion. The crankshaft is a rotating shaft containing one or more crankpins, that are driven by the pistons via the connecting ...

are required for each power stroke. The split-cycle engine divides these four strokes between two paired cylinders: one for intake and compression, and another for power and exhaust. Compressed air is transferred from the compression cylinder to the power cylinder through a crossover passage. Fuel is then injected and fired to produce the power stroke.

History

The Backus Water Motor Company of

Newark, New Jersey Newark ( , ) is the most populous city in the U.S. state of New Jersey and the seat of Essex County and the second largest city within the New York metropolitan area.hot-tube ignitor A hot-tube ignitor was an early device that fit onto the cylinder head of an internal-combustion engine, used to ignite the compressed fuel/air mixture by means of a flame heating part of the tube red-hot. A hot-tube ignitor consisted of a metal o ...

system. It was produced in sizes ranging from 1/2 to and the company had plans to offer a scaled-up version capable of or more. The Atkinson differential engine was a two piston, single cylinder

four-stroke engine A four-stroke (also four-cycle) engine is an internal combustion (IC) engine in which the piston completes four separate strokes while turning the crankshaft. A stroke refers to the full travel of the piston along the cylinder, in either directio ...

that also used a displacer piston to provide the fuel air mixture for use by the power piston. However, the power piston did the compression. The

twingle engine In internal combustion engines, a split-single design is a type of two-stroke where two cylinders share a single combustion chamber. The first production split-single engine was built in 1918 and the design was used on several motorcycles and ...

(U.S. English) or

split-single In internal combustion engines, a split-single design is a type of two-stroke where two cylinders share a single combustion chamber. The first production split-single engine was built in 1918 and the design was used on several motorcycles and ca ...

engine (British English) is a twin cylinder (or more)

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 t ...

; more precisely, it has one or more U-tube cylinders that each use a pair of pistons, one in each arm of the U. However, both pistons in each pair are used for power (and the underside of both supplies fuel air mixture, if crankcase scavenging is used), and they only differ in that one piston works the transfer port to provide the fuel air mixture for use in both cylinders and the other piston works the exhaust port, so that the burnt mixture is exhausted via that cylinder. Unlike the Scuderi both cylinders are connected to the combustion chamber. As neither piston works as a displacer piston at all, this engine has nothing whatsoever to do with the split cycle engine apart from a purely coincidental similarity of the names. The

Scuderi engine The Scuderi engine, formally called the Scuderi Split Cycle Engine, is a split cycle, internal combustion engine invented by Carmelo J. Scuderi (April 13, 1925 – October 16, 2002). Scuderi Group, an engineering and licensing company based ...

is a design of a split-cycle,

invented by Carmelo J. Scuderi. The Scuderi Group, an engineering and licensing company based in

West Springfield, Massachusetts West Springfield is a city in Hampden County, Massachusetts, United States. It is part of the Springfield, Massachusetts Metropolitan Statistical Area. The population was 28,835 at the 2020 United States Census. The city is also known as "West Si ...

and founded by Carmelo Scuderi’s children, said that the prototype was completed and was unveiled to the public on April 20, 2009. The Tour Engine is an opposed-cylinder split-cycle internal combustion engine that uses a novel Spool Shuttle Crossover Valve (SSCV) to transfer fuel/air charge from the cold to hot cylinder. The first prototype was completed on June, 2008. Tour Engine was funded by grants from the

Israel Israel (; he, יִשְׂרָאֵל, ; ar, إِسْرَائِيل, ), officially the State of Israel ( he, מְדִינַת יִשְׂרָאֵל, label=none, translit=Medīnat Yīsrāʾēl; ), is a country in Western Asia. It is situated ...

Ministry of National Infrastructures, Energy and Water Resources The Ministry of Energy ( he, משרד האנרגיה) is the Israeli cabinet, Israeli government ministry responsible for energy and water infrastructure. The ministry has changed names several times since its establishment. The ministerial post w ...

and

ARPA-E ARPA-E, or Advanced Research Projects Agency–Energy is a United States government agency tasked with promoting and funding research and development of advanced energy technologies. It is modeled after the Defense Advanced Research Projects Agenc ...

Another split-cycle design, using an external combustion chamber, is the Zajac engine. A split cycle engine invented by New Zealander Rick Mayne used a multitude of small cylinders arranged in a radial arrangement with pistons operated by a Geneva mechanism. This engine was never successfully run in a meaningful demonstration, but significant capital was raised through a share plan.

References

{{Piston engine configurations, state=uncollapsed Engine technology Piston engines