Doxford opposed piston engine
The Doxford opposed piston engine was built by Hugo Junkers' patents at the William Doxford & Sons shipyard and engineering company in Pallion , Sunderland on the Wear River in England from 1913 to 1979.
History of the opposed piston engine
The shipyard and machine factory William Doxford & Sons in Sunderland had made the step from wooden shipbuilding to iron shipbuilding in contrast to many shipyards and among other things had built offices for construction and workshops for the construction of steam engines. Around 1900 one began to deal with the design and construction of steam turbines and diesel engines.
With patents from Hugo Junkers
Junkers and O Wechselhauser had designed, patented and commissioned an opposed piston gas engine in Dessau in 1893 , which developed 220 hp at 140 rpm. This engine was built and delivered under license by Borsig in Berlin-Tegel , among others . These engines were built in twin design up to an output of 9000 hp. Junkers later used this principle to design diesel engines using the two-stroke process, both in the single-cylinder design and in tandem design. In the complicated tandem version, two cylinders are one behind the other and four pistons are arranged in the cylinder axis.
Several ships such as the Primus received such Junkers diesel engines in tandem, but they were too complicated and difficult to operate and ended in failure. Instead, the ships received steam engines or single-acting two-stroke diesel engines.
Doxford opposed piston engine
The Doxford opposed piston engine with two pistons per cylinder, built according to the Junkers patent, developed quite differently.
Test stand with water brake
Doxford engine of type 58JS3
Doxford engine of type 58JS3
Turbocharged Doxford engine
Crosshead Doxford engine
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The Swiss engineer Karl Otto Keller, who had previously worked for Sulzer , started at Doxford in 1905 and worked for three years with steam engines, gas and diesel engines. Doxford decided to build diesel engines and in 1912 acquired the only Junkers license for England to build an opposed piston engine. A year earlier, Keller came back to work intensively on the construction of these diesel engines as head of construction. After the construction of the first prototype of the single-cylinder machine with opposed pistons, the tests began on the test bench in the hall, but they did not lead to success. When Junkers read this, he sent a few employees to Doxford in England, who together with Otto Keller and William Purdie built a second single-cylinder machine. The bore was 500 mm and the stroke of the two pistons was 750 mm each. After some initial problems on the test bench, the engine ran with an output of 500 hp at 130 rpm. The collaboration between Junkers and Doxford ended with the outbreak of the First World War. After the war, Doxford continued the development and constructed multi-cylinder engines and built them into ships. The first ship was the Yngaren for Swedish owners.
- 1 Yngaren (born Doxfords June 1921, 9000 to 3000 hp, to Sweden)
- 2 Devon-City (built in 1921, 9000 to 3000 hp)
- 3 Pacific Commerce (built February 1922 from 9000 to 2700 hp)
- 4 Eknaren (built in September 1922 9000 bis, 3000 hp, to Sweden)
- 5 Pacific Shipper (built 1924 to 9500, built 3200 HP)
In 1979 the construction of these marine diesel engines was stopped. The complicated construction was one of the reasons and the competition from MAN and Sulzer, especially with regard to the specific fuel consumption, had become overwhelming.
Engine description
The Doxford opposed piston engine worked in the two-stroke process and had a cylinder liner with slots at the top and bottom, which were used to supply air and flush the combustion gases. Two opposing pistons in the cylinder compressed the air and around the end of the compression, the fuel was added with the help of compressed air. The high temperature caused the fuel to ignite and the mixture to expand. The lower piston transmitted the power directly to the crankshaft via a crosshead. The upper piston was positively connected to a crosshead. Two vertical tie rods then also transferred the force as lateral piston rods to the crankshaft. Therefore, the crankshaft for the single cylinder engine had three cranks.
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- Sass, Friedrich: History of the German internal combustion engine construction. 1962 Springer Verlag
- Many pictures of the engine and production: [1]