Opposed piston engine - Revision history

Red marquis at 16:51, 24 May 2010

2010-05-24T16:51:14Z

← Older revision		Revision as of 16:51, 24 May 2010
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	==Configurations==		==Configurations==

	Some variations of the Opposed Piston or OP designs use a single [[crankshaft]] like the Doxford ship engines<ref name="oldengine1">{{Cite web\|url= http://www.oldengine.org/members/diesel/Marine/doxford.htm \|title= Marine Engines – Doxford - Page 1\|accessdate=2010-02-23 \|publisher= OldEngine.org}}</ref> and the Commer OP truck engines.<ref name="oldengine2">{{Cite web\|url= http://www.oldengine.org/members/diesel/technical/TS3.htm \|title= Rootes-Lister – TS3 Horizontally Opposed Piston Engine Page 1 \|accessdate= 2008-03-23\|publisher= OldEngine.org}}</ref>~~{{deadlink\|date=February 2010}}~~ They should not be confused with [[flat engine]]s. Though flat engines are sometimes referred to as horizontally opposed, they are very different mechanically.		Some variations of the Opposed Piston or OP designs use a single [[crankshaft]] like the Doxford ship engines<ref name="oldengine1">{{Cite web\|url= http://www.oldengine.org/members/diesel/Marine/doxford.htm \|title= Marine Engines – Doxford - Page 1\|accessdate=2010-02-23 \|publisher= OldEngine.org}}</ref> and the Commer OP truck engines.<ref name="oldengine2">{{Cite web\|url= http://www.oldengine.org/members/diesel/technical/TS3.htm \|title= Rootes-Lister – TS3 Horizontally Opposed Piston Engine Page 1 \|accessdate= 2008-03-23\|publisher= OldEngine.org}}</ref> They should not be confused with [[flat engine]]s. Though flat engines are sometimes referred to as horizontally opposed, they are very different mechanically.

	A more common layout uses 2 crankshafts, with the crankshafts geared together, or even 3 geared crankshafts in the [[Napier Deltic]] diesel engines. The Deltic uses three crankshafts serving three banks of double-ended cylinders arranged in an equilateral triangle, with the crankshafts at the corners. These were used in [[railway ~~locomotive]]s~~ and to power fast patrol boats. Both types are now largely obsolete, although the [[Royal Navy]] still maintains some Deltic-powered [[Hunt class mine countermeasure ~~vessel]]s~~.		A more common layout uses 2 crankshafts, with the crankshafts geared together, or even 3 geared crankshafts in the Napier Deltic diesel engines. The Deltic uses three crankshafts serving three banks of double-ended cylinders arranged in an equilateral triangle, with the crankshafts at the corners. These were used in railway locomotives and to power fast patrol boats. Both types are now largely obsolete, although the Royal Navy still maintains some Deltic-powered Hunt class mine countermeasure vessels.

	The first opposed-piston diesel engines were developed in the beginning of 20th century. In 1907, Raymond Koreyvo, the engineer of Kolomna Works, patented and built opposed-piston two-stroke diesel with two crankshafts, connected by gearing. Although Koreyvo patented his diesel in France in November, 1907, the direction would not go on to manufacture opposed-piston engines.		The first opposed-piston diesel engines were developed in the beginning of 20th century. In 1907, Raymond Koreyvo, the engineer of Kolomna Works, patented and built opposed-piston two-stroke diesel with two crankshafts, connected by gearing. Although Koreyvo patented his diesel in France in November, 1907, the direction would not go on to manufacture opposed-piston engines.

	The first Junkers engines had one crankshaft, the upper pistons having long connecting rods outside the cylinder. These engines were the forerunner of the Doxford marine engine, and this layout was also used for two- and three-cylinder car engines from around 1900 to 1922 by Gobron-Brillié.<ref>{{cite book\|title= Some Unusual Engines \|author= L.J.K. Setright \|ISBN=0 85298 208 9}}</ref> There is currently a resurgence of this design in a boxer configuration as a small [[diesel aircraft engine]], and for other application, called the 'OPOC'<ref>{{cite web\|url= http://www.propulsiontech.com/opocengine.html \|title= The Patented opoc Engine \|accessdate=2010-02-23}}</ref> engine by Advanced Propulsion Technologies, Inc. of [[California]].<ref name="enginetech1">{{Cite web\|url= http://home.arcor.de/hildst/EnEx99e.html \|title= Stroke of genius – OPOC takes two \|accessdate=2010-02-23 \|author= Peter Hofbauer \|publisher= Engine Technology International}}</ref> Later Junkers engines like the [[Junkers Jumo 205~~]] [[~~diesel aircraft engine]], use two crankshafts, one at either end of a single bank of cylinders. There are efforts to reintroduce the opposed-piston [[diesel aircraft engine]] with twin geared crankshafts for [[General aviation]] applications, by both Dair and PowerPlant Developments in the UK.<ref name="dieselair1" >{{Cite web\|url= http://www.dair.co.uk/ \|title= The 100hp Liquid Cooled Diesel Aircraft Engine \|accessdate =2010-02-23 \|publisher= Diesel Air Limited}}</ref>		The first Junkers engines had one crankshaft, the upper pistons having long connecting rods outside the cylinder. These engines were the forerunner of the Doxford marine engine, and this layout was also used for two- and three-cylinder car engines from around 1900 to 1922 by Gobron-Brillié.<ref>{{cite book\|title= Some Unusual Engines \|author= L.J.K. Setright \|ISBN=0 85298 208 9}}</ref> There is currently a resurgence of this design in a boxer configuration as a small diesel aircraft engine, and for other application, called the 'OPOC'<ref>{{cite web\|url= http://www.propulsiontech.com/opocengine.html \|title= The Patented opoc Engine \|accessdate=2010-02-23}}</ref> engine by Advanced Propulsion Technologies, Inc. of California.<ref name="enginetech1">{{Cite web\|url= http://home.arcor.de/hildst/EnEx99e.html \|title= Stroke of genius – OPOC takes two \|accessdate=2010-02-23 \|author= Peter Hofbauer \|publisher= Engine Technology International}}</ref> Later Junkers engines like the Junkers Jumo 205 diesel aircraft engine, use two crankshafts, one at either end of a single bank of cylinders. There are efforts to reintroduce the opposed-piston diesel aircraft engine with twin geared crankshafts for General aviation applications, by both Dair and PowerPlant Developments in the UK.<ref name="dieselair1" >{{Cite web\|url= http://www.dair.co.uk/ \|title= The 100hp Liquid Cooled Diesel Aircraft Engine \|accessdate =2010-02-23 \|publisher= Diesel Air Limited}}</ref>

	This configuration has also been used for marine auxiliary generators and for larger marine propulsion engines, notably [[Fairbanks-Morse]] [[diesel engine]]s used in both conventional and nuclear US [[submarines]]. Fairbanks-Morse also used it in [[diesel locomotives]] starting in 1944. With the addition of a [[supercharger]] or [[turbocharger]], opposed-piston designs can make very efficient [[two-stroke cycle]] Diesel engines. Attempts were made to build non-diesel 4-stroke engines, but as there is no cylinder head, the bad location of the valves and the spark plug makes them inefficient.		This configuration has also been used for marine auxiliary generators and for larger marine propulsion engines, notably Fairbanks-Morse [[diesel engine]]s used in both conventional and nuclear US submarines. Fairbanks-Morse also used it in diesel locomotives starting in 1944. With the addition of a [[supercharger]] or [[turbocharger]], opposed-piston designs can make very efficient [[two-stroke cycle]] Diesel engines. Attempts were made to build non-diesel 4-stroke engines, but as there is no cylinder head, the bad location of the valves and the spark plug makes them inefficient.

	Koreyvo, Jumo and Deltic engines used one piston per cylinder to expose an intake port, and the other to expose an exhaust port. Each piston is referred to as either an ''intake piston'' or an ''exhaust piston'' depending on its function in this regard. This layout gives superior scavenging, as gas flow through the cylinder is axial rather than radial, and simplifies design of the piston crowns. In the Jumo 205 and its variants, the upper crankshaft serves the exhaust pistons, and the lower crankshaft the intake pistons. In designs using multiple cylinder banks, such as the [[Junkers Jumo 223]] and the Deltic, each big end bearing serves one inlet and one exhaust piston, using a forked connecting rod for the exhaust piston.		Koreyvo, Jumo and Deltic engines used one piston per cylinder to expose an intake port, and the other to expose an exhaust port. Each piston is referred to as either an ''intake piston'' or an ''exhaust piston'' depending on its function in this regard. This layout gives superior scavenging, as gas flow through the cylinder is axial rather than radial, and simplifies design of the piston crowns. In the Jumo 205 and its variants, the upper crankshaft serves the exhaust pistons, and the lower crankshaft the intake pistons. In designs using multiple cylinder banks, such as the Junkers Jumo 223 and the Deltic, each big end bearing serves one inlet and one exhaust piston, using a forked connecting rod for the exhaust piston.

	The Doxford Engine Works of the UK designed and built very large opposed-piston engines for marine use. These engines differ in design from Jumo and Fairbanks-Morse engines by having external connecting rods outside the cylinder linking the upper and lower pistons, thus requiring only a single crankshaft. The first engine of this type was developed by Karl Otto Keller in 1912. Doxford obtained a sole UK license from Oechelhauser and [[Junkers ~~(Aircraft)\|Junkers]]~~ to build this design of engine. After World War I these engines were produced in a number of models, such as the P and J series, with outputs as high as ~~{{convert\|20000\|hp}}~~. Certain models were license-built in the US. Production of Doxford engines in the UK ceased in 1980.<ref name="doxfordfriends1" >{{Cite web\|url= http://www.doxford-engine.com/ \|title= Doxford Engines 1878–1980 \|accessdate=2010-02-23 \|publisher= Doxford Engine Friends Association}}</ref><ref name="oldengine1" /><ref name="zoeller1" >{{Cite web\|url= http://www.geocities.com/hjunkers/ju_shipengines_a1.htm \|title= Junkers Ship Engines \|accessdate=2008-03-23\|publisher= Horst Zoeller}}</ref>~~{{deadlink\|date=February 2010}}~~		The Doxford Engine Works of the UK designed and built very large opposed-piston engines for marine use. These engines differ in design from Jumo and Fairbanks-Morse engines by having external connecting rods outside the cylinder linking the upper and lower pistons, thus requiring only a single crankshaft. The first engine of this type was developed by Karl Otto Keller in 1912. Doxford obtained a sole UK license from Oechelhauser and Junkers to build this design of engine. After World War I these engines were produced in a number of models, such as the P and J series, with outputs as high as 20,000 horsepower (15,000 kW). Certain models were license-built in the US. Production of Doxford engines in the UK ceased in 1980.<ref name="doxfordfriends1" >{{Cite web\|url= http://www.doxford-engine.com/ \|title= Doxford Engines 1878–1980 \|accessdate=2010-02-23 \|publisher= Doxford Engine Friends Association}}</ref><ref name="oldengine1" /><ref name="zoeller1" >{{Cite web\|url= http://www.geocities.com/hjunkers/ju_shipengines_a1.htm \|title= Junkers Ship Engines \|accessdate=2008-03-23\|publisher= Horst Zoeller}}</ref>

	==Assembly and function==		==Assembly and function==
	The layout of a [[two-stroke engine]] is similar to the one developed by engineer Kurt Bang at the Prüssing Office on the basis of the prewar DKW race engine. There existed two versions: one with a [[engine displacement\|displacement]] of ~~{{convert\|~~250\|cm3~~\|abbr=on}}~~, and one with ~~{{convert\|~~350\|cm3~~\|abbr=on}}~~ displacement. The engine had two [[cylinder (engine)\|cylinder]]s with four [[piston]]s, two [[crankshaft]]s and a [[supercharger]]. The crankshafts were connected by [[gear]]s.		The layout of a [[two-stroke engine]] is similar to the one developed by engineer Kurt Bang at the Prüssing Office on the basis of the prewar DKW race engine. There existed two versions: one with a [[engine displacement\|displacement]] of 250 cm3 (15 cu in), and one with 350 cm3 (21 cu in) displacement. The engine had two [[cylinder (engine)\|cylinder]]s with four [[piston]]s, two [[crankshaft]]s and a [[supercharger]]. The crankshafts were connected by [[gear]]s.

	The supercharger takes in the fuel-air mixture, compressing it and pushing it into the airbox. From here it reaches the crank housings. On the outlet side it cools the thermically high loaded piston. After [[Ignition system\|ignition]] the pistons move outwards, performing the power stroke. At first, the outlet piston opens its slots in the cylinder. The remaining pressure accelerates the gas column towards the exhaust. Then the other piston opens the inlet slots. The pressurized fresh mixture pushes the remaining waste gas out. While the inlet is still opened, the outlet is closed. The supercharger forces additional gas into the cylinder until the inlet slots are closed by the piston. Then the compression stroke starts and the cycle repeats. This type of two cycle system is similar to the famous Grey Marine Diesel, later to be known as the GM Diesel ([[Detroit Diesel]]). Production ceased in 1998 but the U.S. and British Militaries still purchase remanufactured engines on occasion.~~{{Citation needed\|date=January 2010}}~~		The supercharger takes in the fuel-air mixture, compressing it and pushing it into the airbox. From here it reaches the crank housings. On the outlet side it cools the thermically high loaded piston. After [[Ignition system\|ignition]] the pistons move outwards, performing the power stroke. At first, the outlet piston opens its slots in the cylinder. The remaining pressure accelerates the gas column towards the exhaust. Then the other piston opens the inlet slots. The pressurized fresh mixture pushes the remaining waste gas out. While the inlet is still opened, the outlet is closed. The supercharger forces additional gas into the cylinder until the inlet slots are closed by the piston. Then the compression stroke starts and the cycle repeats. This type of two cycle system is similar to the famous Grey Marine Diesel, later to be known as the GM Diesel ([[Detroit Diesel]]). Production ceased in 1998 but the U.S. and British Militaries still purchase remanufactured engines on occasion.

	==Free-piston engine==		==Free-piston engine==
	{{Main\|Free-piston engine}}		{{Main\|Free-piston engine}}
	An interesting variation on the opposed-piston engine is the free-piston engine which was patented in 1934 by [[Raúl Pateras de Pescara]]. It has no crankshaft and the pistons are returned after each firing stroke by compression and expansion of air in a separate cylinder. Early applications were for use as an air compressor or as a gas generator for a [[gas turbine]]. There is now renewed interest in it for powering vehicles by using it to drive a [[linear alternator]].		An interesting variation on the opposed-piston engine is the free-piston engine which was patented in 1934 by Raúl Pateras de Pescara. It has no crankshaft and the pistons are returned after each firing stroke by compression and expansion of air in a separate cylinder. Early applications were for use as an air compressor or as a gas generator for a gas turbine. There is now renewed interest in it for powering vehicles by using it to drive a linear alternator.

	"Amazing New Lightweight Turbine Engine" was the cover story in the February 1969 issue of Mechanix Illustrated magazine. It was actually a free-piston engine, not a turbine, and was used to power a go-cart.		"Amazing New Lightweight Turbine Engine" was the cover story in the February 1969 issue of Mechanix Illustrated magazine. It was actually a free-piston engine, not a turbine, and was used to power a go-cart.

	~~==Other notable opposed-piston engines==~~
	*[[Junkers Jumo 205]].
	*[[Commer TS3]] "The Commer Knocker" commercial vehicle engine.
	*[[Leyland L60]] [[tank]] engine, used in the [[Chieftain tank]].Similar in layout to the Junkers Jumo 205 and [[Napier & Son\|Napier]] Culverin.
	*[[Rolls-Royce K60]] engine, smaller and improved version of the L60 used in the [[FV430]] series [[armoured fighting vehicles]] and swedish tank [[Strv 103]].
	*[[Napier Deltic]].
	*Soviet engine 5TDF used on tank [[T-64]].
	*Soviet engine 6TD used on tanks [[T-80UD]], [[T-84]] and [[Al-Khalid (tank)\|Al-Khalid]].

	==See also==		==See also==

Red marquis at 16:34, 24 May 2010

2010-05-24T16:34:05Z

New page

An '''opposed-piston engine''' is one in which the cylinders are double-ended, with a piston at each end and no cylinder head.

==Configurations==

Some variations of the Opposed Piston or OP designs use a single [[crankshaft]] like the Doxford ship engines<ref name="oldengine1">{{Cite web|url= http://www.oldengine.org/members/diesel/Marine/doxford.htm |title= Marine Engines – Doxford - Page 1|accessdate=2010-02-23 |publisher= OldEngine.org}}</ref> and the Commer OP truck engines.<ref name="oldengine2">{{Cite web|url= http://www.oldengine.org/members/diesel/technical/TS3.htm |title= Rootes-Lister – TS3 Horizontally Opposed Piston Engine Page 1 |accessdate= 2008-03-23|publisher= OldEngine.org}}</ref>{{deadlink|date=February 2010}} They should not be confused with [[flat engine]]s. Though flat engines are sometimes referred to as horizontally opposed, they are very different mechanically.

A more common layout uses 2 crankshafts, with the crankshafts geared together, or even 3 geared crankshafts in the [[Napier Deltic]] diesel engines. The Deltic uses three crankshafts serving three banks of double-ended cylinders arranged in an equilateral triangle, with the crankshafts at the corners. These were used in [[railway locomotive]]s and to power fast patrol boats. Both types are now largely obsolete, although the [[Royal Navy]] still maintains some Deltic-powered [[Hunt class mine countermeasure vessel]]s.

The first opposed-piston diesel engines were developed in the beginning of 20th century. In 1907, Raymond Koreyvo, the engineer of Kolomna Works, patented and built opposed-piston two-stroke diesel with two crankshafts, connected by gearing. Although Koreyvo patented his diesel in France in November, 1907, the direction would not go on to manufacture opposed-piston engines.

The first Junkers engines had one crankshaft, the upper pistons having long connecting rods outside the cylinder. These engines were the forerunner of the Doxford marine engine, and this layout was also used for two- and three-cylinder car engines from around 1900 to 1922 by Gobron-Brillié.<ref>{{cite book|title= Some Unusual Engines |author= L.J.K. Setright |ISBN=0 85298 208 9}}</ref> There is currently a resurgence of this design in a boxer configuration as a small [[diesel aircraft engine]], and for other application, called the 'OPOC'<ref>{{cite web|url= http://www.propulsiontech.com/opocengine.html |title= The Patented opoc Engine |accessdate=2010-02-23}}</ref> engine by Advanced Propulsion Technologies, Inc. of [[California]].<ref name="enginetech1">{{Cite web|url= http://home.arcor.de/hildst/EnEx99e.html |title= Stroke of genius – OPOC takes two |accessdate=2010-02-23 |author= Peter Hofbauer |publisher= Engine Technology International}}</ref> Later Junkers engines like the [[Junkers Jumo 205]] [[diesel aircraft engine]], use two crankshafts, one at either end of a single bank of cylinders. There are efforts to reintroduce the opposed-piston [[diesel aircraft engine]] with twin geared crankshafts for [[General aviation]] applications, by both Dair and PowerPlant Developments in the UK.<ref name="dieselair1" >{{Cite web|url= http://www.dair.co.uk/ |title= The 100hp Liquid Cooled Diesel Aircraft Engine |accessdate =2010-02-23 |publisher= Diesel Air Limited}}</ref>

This configuration has also been used for marine auxiliary generators and for larger marine propulsion engines, notably [[Fairbanks-Morse]] [[diesel engine]]s used in both conventional and nuclear US [[submarines]]. Fairbanks-Morse also used it in [[diesel locomotives]] starting in 1944. With the addition of a [[supercharger]] or [[turbocharger]], opposed-piston designs can make very efficient [[two-stroke cycle]] Diesel engines. Attempts were made to build non-diesel 4-stroke engines, but as there is no cylinder head, the bad location of the valves and the spark plug makes them inefficient.

Koreyvo, Jumo and Deltic engines used one piston per cylinder to expose an intake port, and the other to expose an exhaust port. Each piston is referred to as either an ''intake piston'' or an ''exhaust piston'' depending on its function in this regard. This layout gives superior scavenging, as gas flow through the cylinder is axial rather than radial, and simplifies design of the piston crowns. In the Jumo 205 and its variants, the upper crankshaft serves the exhaust pistons, and the lower crankshaft the intake pistons. In designs using multiple cylinder banks, such as the [[Junkers Jumo 223]] and the Deltic, each big end bearing serves one inlet and one exhaust piston, using a forked connecting rod for the exhaust piston.

The Doxford Engine Works of the UK designed and built very large opposed-piston engines for marine use. These engines differ in design from Jumo and Fairbanks-Morse engines by having external connecting rods outside the cylinder linking the upper and lower pistons, thus requiring only a single crankshaft. The first engine of this type was developed by Karl Otto Keller in 1912. Doxford obtained a sole UK license from Oechelhauser and [[Junkers (Aircraft)|Junkers]] to build this design of engine. After World War I these engines were produced in a number of models, such as the P and J series, with outputs as high as {{convert|20000|hp}}. Certain models were license-built in the US. Production of Doxford engines in the UK ceased in 1980.<ref name="doxfordfriends1" >{{Cite web|url= http://www.doxford-engine.com/ |title= Doxford Engines 1878–1980 |accessdate=2010-02-23 |publisher= Doxford Engine Friends Association}}</ref><ref name="oldengine1" /><ref name="zoeller1" >{{Cite web|url= http://www.geocities.com/hjunkers/ju_shipengines_a1.htm |title= Junkers Ship Engines |accessdate=2008-03-23|publisher= Horst Zoeller}}</ref>{{deadlink|date=February 2010}}

==Assembly and function==
The layout of a [[two-stroke engine]] is similar to the one developed by engineer Kurt Bang at the Prüssing Office on the basis of the prewar DKW race engine. There existed two versions: one with a [[engine displacement|displacement]] of {{convert|250|cm3|abbr=on}}, and one with {{convert|350|cm3|abbr=on}} displacement. The engine had two [[cylinder (engine)|cylinder]]s with four [[piston]]s, two [[crankshaft]]s and a [[supercharger]]. The crankshafts were connected by [[gear]]s.

The supercharger takes in the fuel-air mixture, compressing it and pushing it into the airbox. From here it reaches the crank housings. On the outlet side it cools the thermically high loaded piston. After [[Ignition system|ignition]] the pistons move outwards, performing the power stroke. At first, the outlet piston opens its slots in the cylinder. The remaining pressure accelerates the gas column towards the exhaust. Then the other piston opens the inlet slots. The pressurized fresh mixture pushes the remaining waste gas out. While the inlet is still opened, the outlet is closed. The supercharger forces additional gas into the cylinder until the inlet slots are closed by the piston. Then the compression stroke starts and the cycle repeats. This type of two cycle system is similar to the famous Grey Marine Diesel, later to be known as the GM Diesel ([[Detroit Diesel]]). Production ceased in 1998 but the U.S. and British Militaries still purchase remanufactured engines on occasion.{{Citation needed|date=January 2010}}

==Free-piston engine==
{{Main|Free-piston engine}}
An interesting variation on the opposed-piston engine is the free-piston engine which was patented in 1934 by [[Raúl Pateras de Pescara]]. It has no crankshaft and the pistons are returned after each firing stroke by compression and expansion of air in a separate cylinder. Early applications were for use as an air compressor or as a gas generator for a [[gas turbine]]. There is now renewed interest in it for powering vehicles by using it to drive a [[linear alternator]].

"Amazing New Lightweight Turbine Engine" was the cover story in the February 1969 issue of Mechanix Illustrated magazine. It was actually a free-piston engine, not a turbine, and was used to power a go-cart.

==Other notable opposed-piston engines==
*[[Junkers Jumo 205]].
*[[Commer TS3]] "The Commer Knocker" commercial vehicle engine.
*[[Leyland L60]] [[tank]] engine, used in the [[Chieftain tank]].Similar in layout to the Junkers Jumo 205 and [[Napier & Son|Napier]] Culverin.
*[[Rolls-Royce K60]] engine, smaller and improved version of the L60 used in the [[FV430]] series [[armoured fighting vehicles]] and swedish tank [[Strv 103]].
*[[Napier Deltic]].
*Soviet engine 5TDF used on tank [[T-64]].
*Soviet engine 6TD used on tanks [[T-80UD]], [[T-84]] and [[Al-Khalid (tank)|Al-Khalid]].

==See also==

{{Piston engine configurations}}

==External links==
* [http://www.psrm.org/roster/diesel/fm/index.html Fairbanks-Morse 38D8 Diesel Engine]

[[Category:Two-stroke diesel engines]]
[[Category:Opposed piston engines]]