Fairbanks-Morse opposed piston diesel engines 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. It should not be confused with the flat engine (often called a "Boxer" or "horizontally opposed engine") which has a single crankshaft with its two cylinder banks set 180° apart. Image File history File links Download high resolution version (1600x1200, 460 KB) Opposed-piston Fairbanks-Morse diesel engine on the submarine Potanipo This submarine is permanently docked in San Francisco and can be toured as part of the Maritime Museum. ... Image File history File links Download high resolution version (1600x1200, 460 KB) Opposed-piston Fairbanks-Morse diesel engine on the submarine Potanipo This submarine is permanently docked in San Francisco and can be toured as part of the Maritime Museum. ... The diesel engine is a type of internal combustion engine; more specifically, it is a compression ignition engine, in which the fuel is ignited by being suddenly exposed to the high temperature and pressure of a compressed gas, rather than by a separate source of ignition, such as a spark... German UC-1 class World War I submarine A model of Gunter Priens Unterseeboot 47 (U-47), German WWII Type VII diesel-electric hunter-killer (SSK) submarine USS Virginia, a Virginia-class nuclear attack (SSN) submarine A submarine is a specialized watercraft that can operate underwater. ... USS Pampanito (SS-383), a Balao-class submarine, was the only ship of the United States Navy to be named for the gafftopsail pompano, Trachinotus rhodopus. ... A flat engine is an internal combustion engine in which the cylinders are arranged in two banks on either side of a single crankshaft so that the motion of all the pistons is in a single plane. ... Crankshaft, pistons, and flywheel Continental engine marine crankshafts, 1942 For the comic strip about an old, curmudgeonly bus driver, see Crankshaft (comic strip). ...

This type of configuration was used in the Junkers Jumo 205 diesel aircraft engine, with two crankshafts, one at either end of a single bank of cylinders. Other Junkers engines had but one crankshaft, the upper pistons having long connecting rods outside the cylinder (see below). Even more remarkable were the Napier Deltic diesel engines, with 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 Junkers Jumo 205 aircraft engine was the most famous of a series of diesel engines that were the first, and for more than half a century, the only successful diesel aircraft engines. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Napier Deltic powered British Rail Class 55 Alycidon, at the National Railway Museum, York, UK The term Deltic (meaning in the form of the Greek letter Delta) is used to refer to both the opposed piston high speed diesel engine designed and produced by Napier & Son, and the locomotives produced... The Royal Navy of the United Kingdom is the senior service of the British armed services being the oldest of its three branches. ...

An April, 1950 print advertisement for Fairbanks-Morse opposed piston engines.

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. Some 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. Image File history File links Download high resolution version (582x800, 77 KB)A print advertisement for the FM Opposed Piston Engine dated 4-17-50. ... Image File history File links Download high resolution version (582x800, 77 KB)A print advertisement for the FM Opposed Piston Engine dated 4-17-50. ... Fairbanks-Morse, located in Beloit, Wisconsin has specialized in the manufacture of opposed piston diesel engines for United States Naval vessels and railroad locomotives since 1932. ... The diesel engine is a type of internal combustion engine; more specifically, it is a compression ignition engine, in which the fuel is ignited by being suddenly exposed to the high temperature and pressure of a compressed gas, rather than by a separate source of ignition, such as a spark... USS Los Angeles A submarine is a specialized watercraft that can operate underwater. ... Great Western Railway No. ... A supercharger (also known as a blower) is an air compressor used to compress air into the cylinders of an internal combustion engine. ... Air foil bearing-supported turbocharger cutaway made by Mohawk Innovative Technology Inc. ... The two-stroke cycle of an internal combustion engine differs from the more common four-stroke cycle by having only two strokes (linear movements of the piston) instead of four, although the same four operations (intake, compression, power, exhaust) still occur. ...

Both the 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 Junkers Jumo 223 was an experimental 24-cylinder aircraft engine based on the Junkers Jumo 205. ...

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 1, 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. [1] [2] [3] For the Prussian/German landowning classes, see junker. The name Junkers (IPA: /ˈjunkeɺs/) is well known in connection with aircraft, which were produced under this name for the Luftwaffe during World War II. In particular the Ju 87 Stuka and Ju 52 Tante Ju were common symbols of the...

Assembly and function

An example of an opposed piston engine.
1 intake for the fuel-air mixture
2 supercharger (here: rotary vane pump; original: Centrix)
3 airbox to buffer and distribute the mixture
4 waste valve to limit the pressure level
5 outlet crank mechanism
6 inlet crank mechanism (runs app. 20° past the outlet to achieve an asymmetric control diagram)
7 cylinder with inlet and outlet slots
8 exhaust
9 water cooling jacket
10 sparkplug
For an animation see here (587 kByte), for a view in perspective here.

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 displacement of 250 cm³, and one with 350 cm³ displacement. The engine had two cylinders 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 fuel consumption. Image File history File links sectional view of an opposite piston engine Animierte Schnittansicht eines Gegenkolbenmotors Source: self-made UtzOnBike with Autodesk Inventor File links The following pages link to this file: Opposed piston engine ... Image File history File links Animated sectional view of an opposite piston engine / Animierte Schnittansicht eines Gegenkolbenmotors Source: self-made UtzOnBike with Autodesk Inventor File links There are no pages that link to this file. ... Image File history File links Download high resolution version (775x808, 83 KB) Sectional view of opposite piston engine in perspective / Perspektivische Schnittansicht eines Gegenkolbenmotors Source: self-made UtzOnBike with Autodesk Inventor File links There are no pages that link to this file. ... Engine displacement is defined as the total volume of air/fuel mixture an engine can draw in during one complete engine cycle; it is normally stated in cubic centimetres, litres or cubic inches. ... A piston and cylinder from a steam engine A cylinder in an internal combustion engine is the space within which a piston travels. ... piston + connecting rod In general, a piston is a sliding plug that fits closely inside the bore of a cylinder. ... Crankshaft, pistons, and flywheel Continental engine marine crankshafts, 1942 For the comic strip about an old, curmudgeonly bus driver, see Crankshaft (comic strip). ... A supercharger (also known as a blower) is an air compressor used to compress air into the cylinders of an internal combustion engine. ... Spur gears found on a piece of farm equipment. ... Stromberg side-draft carburetor The carburetor (American spelling, also carburettor, carburetter, carburator, carb for short, or carbie (slang)) is a device which mixes air and fuel for an internal-combustion engine. ... Specific fuel consumption, often shortened to SFC, is an engineering term that is used to describe the fuel efficiency of an engine design. ...

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 presses additional gas into the cylinder until the inlet slots are closed by the piston. Now the compression stroke starts and the cycle repeats. This type of two cycle system was a similar version of the famous Grey Marine Diesel later to be known as the GM Diesel (Detroit Diesel). In 1998 the seize of production of that brand was halted as well due to the cost of four cycle diesel's being more readily available cheaper. The U.S. and British Militarys still receive remanifacted engines if needed due to high demand.

External links

• Fairbanks-Morse 38D8 Diesel Engine