Shopping on line can be easy, simple and save you lots of money. It can also take a lot of your time, frustrate you, and result in unwanted purchases. Now the same can be said for regular high street shopping, but with the vast opportunity presented by the Internet it will pay you to spend a few minutes reading this and understanding how to better optimize your Opposed Piston shopping experience:
1. Compare - without doubt the biggest advantage that the Opposed Piston offers shoppers today is the ability to compare thousands of Opposed Piston at a time. This is a great thing, but not necessarily all the time! Too much can be daunting at times so take advantage of the great comparison sites and where possible let them do the hard work for you.
2. Research - if it has been said it will be on the internet. Ignorance is no longer a justifiable reason for buying the wrong thing. Take the time to research in detail everything that you could possible want to know about
3. Testimonials - don't know anybody that has bought a Opposed Piston? Wrong! If the Opposed Piston is good the internet will let you know. Use the Internet as a friend and get testimonials before you buy.
4. Questions - Got a question about Opposed Piston then search the Forums, FAQ's, Blogs etc. Don't be afraid to ask .....
5. Reputation - Never heard of the company selling Opposed Piston? Don't worry, no reason why you should know every company in the world, but you know someone that does! Use the internet to find out what people are saying about Opposed Piston and build up a picture of their reputation for sales, returns, customer service, delivery etc.
6. Returns - still worried that even after all of the above your Opposed Piston wont be what you want? Check out the returns policy. There is so much competition now that someone, somewhere is bound to offer the terms that you are comfortable with.
7. Feedback - happy with your Opposed Piston then let people know, after all you are depending on others people input in your buying decision, so why not give a little back.
8. Security - check for the yellow padlock on the Opposed Piston site before you buy, and the s after http:/ /i.e. https:// = a secure site
9. Contact - got a question about Opposed Piston, or want to leave a comment then check out the sites contact page. Reputable companies have them and respond.
10. Payment - ready to pay for your Opposed Piston, then use your credit card or PayPal! Be aware of companies that don't accept them, there may be genuine reasons but given the huge amount of choice you have when buying online there is no reason at all not to buy via credit card or PayPal.
s on the
submarine USS Pampanito.
An
opposed piston engine is one in which the cylinders are double-ended, with a piston at each end and no cylinder head. Some variations of the Opposed Piston or OP designs can use a single
crankshaft like the Doxford ship engines and the Commer OP truck engines They should not be confused with a
flat engine, which is referred to as horizontally opposed, or sometimes as a "Boxer" engine.
Configurations
Junkers Jumo 205A more common layout uses 2 crankshafts or even 3 Crankshafts like the Napier Deltic diesel engines. These engines use 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 Junkers engines had one crankshaft, the upper pistons having long connecting rods outside the cylinder. These engine were the forerunner of the Doxford marine engine. There is currently a resurgence of this design in a boxer configuration 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 is also an effort to reintroduce the OP diesel aircraft engine http://www.dair.co.uk/
This configuration has also been used for marine auxiliary generators and for larger marine propulsion engines, notably
Fairbanks-Morse diesel engines 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) 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 20000 hp. Certain models were license-built in the US. Production of Doxford engines in the UK ceased in 1980.
Assembly and function
image:opposite_piston_engine.gif (587 kByte), for a view in perspective :image:opposite_piston_engine_persp.gif.Shown is the layout of an Otto cycle two-stroke engine 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 of 250 cm³, and one with 350 cm³ displacement. The engine had two
cylinder (engine)s with four
pistons, two
crankshafts and a
supercharger. The crankshafts were connected by gears. The fuel-air mixture was produced by a carburetor. This resulted in a high specific fuel consumption.
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 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). In 1998 the production of that brand was halted as well due to the lower cost of available four cycle diesels.
The U.S. and British Militaries still purchase remanufactured engines if needed due to high demand.
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.
"Amazine 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 topower a go-cart.
See also
External links
- Fairbanks-Morse 38D8 Diesel Engine
s on the
submarine USS Pampanito.
An
opposed piston engine is one in which the cylinders are double-ended, with a piston at each end and no cylinder head. Some variations of the Opposed Piston or OP designs can use a single crankshaft like the Doxford ship engines and the Commer OP truck engines They should not be confused with a
flat engine, which is referred to as horizontally opposed, or sometimes as a "Boxer" engine.
Configurations
Junkers Jumo 205A more common layout uses 2 crankshafts or even 3 Crankshafts like the Napier Deltic diesel engines. These engines use 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 Junkers engines had one crankshaft, the upper pistons having long connecting rods outside the cylinder. These engine were the forerunner of the Doxford marine engine. There is currently a resurgence of this design in a boxer configuration 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 is also an effort to reintroduce the OP diesel aircraft engine http://www.dair.co.uk/
This configuration has also been used for marine auxiliary generators and for larger marine propulsion engines, notably
Fairbanks-Morse diesel engines 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) 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 20000 hp. Certain models were license-built in the US. Production of Doxford engines in the UK ceased in 1980.
Assembly and function
image:opposite_piston_engine.gif (587 kByte), for a view in perspective
:image:opposite_piston_engine_persp.gif.Shown is the layout of an Otto cycle two-stroke engine 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 of 250 cm³, and one with 350 cm³ displacement. The engine had two cylinder (engine)s with four pistons, two crankshafts and a
supercharger. The crankshafts were connected by gears. The fuel-air mixture was produced by a
carburetor. This resulted in a high
specific fuel consumption.
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 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). In 1998 the production of that brand was halted as well due to the lower cost of available four cycle diesels.
The U.S. and British Militaries still purchase remanufactured engines if needed due to high demand.
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.
"Amazine 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 topower a go-cart.
See also
External links
- Fairbanks-Morse 38D8 Diesel Engine
Opposed piston engine - Wikipedia, the free encyclopedia
An opposed piston engine is one in which the cylinders are double-ended, with a piston at each end and no cylinder head.
List of Fairbanks-Morse locomotives - Wikipedia, the free encyclopedia
Fairbanks-Morse, is a historic American (and Canadian) industrial scale manufacturer. It later diversified into pumps, engines and industrial supplies.
Fairbanks Morse Engine - an EnPro Industries company
The Fairbanks Morse Opposed Piston (OP) engine has been designed and developed for a wide array of electrical power generation and heavy industrial applications.
Marine Engines
Doxfords built vertical, opposed-piston two-stroke diesel engines for ships, up to 8000 bhp, and their design became a standard unit for British flag-carriers until the licence ...
opposed - definition of opposed by the Free Online Dictionary ...
v. op·posed, op·pos·ing, op·pos·es ... Opposed piston Opposed piston engine Opposed-piston Opposed/Opposite Opposeless
opposed-piston engine - Definitions from Dictionary.com
op·posed-pis·ton en·gine ...
Russian Reforms- Unusual Russian Locomotive Technology.
THE OR23-01 OPPOSED-PISTON STEAM LOCOMOTIVE. 1949 I assume the point of opposed-pistons was to obtain balance of the fore-and-aft forces, which would mean a reduction in wheel ...
Opposed Piston Opposed Cylinder Engine - Engineering TV
An extremely lightweight opposed piston opposed cylinder (OPOC) engine has been developed under a Defense Advanced Research Projects Agency (DARPA) program.
Novelties: TARDEC Opposed Piston Opposed Cylinder 2-Cycle Diesel ...
newVideoPlayer Darpa engine flv Talk about a gee-whiz motor TARDEC is showing off its Opposed Piston Opposed Cylinder Engine OPOC
Opposed Piston Opposed Cylinder (Opoc) Engine for Military Ground ...
Engineering technical paper: Opposed Piston Opposed Cylinder (Opoc) Engine for Military Ground Vehicles
