Diesel engines for the Imperial Navy

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The development and construction of diesel engines for the Imperial Navy in Germany was particularly advanced after the naval laws were passed . In the German Empire, the naval laws provided the legal basis for the construction of the German fleet before the First World War . This resulted in a high demand for drive units for warships.

introduction

Rudolf Diesel with his oil engine, as diesel engines were initially called

As one of the first developers and entrepreneurs, Rudolf Diesel was looking for a company to build his newly developed engine principle in parallel to his correspondence with the Munich patent office. After lengthy negotiations, the machine works Augsburg, from 1908 Augsburg-Nuremberg MAN , and soon Krupp too, agreed to finance an engine based on Diesel's designs. For this they became co-owners of Diesel's patents .

Experimental machines from 1893

First test engine in Augsburg

This first test machine was designed at MAN in Augsburg in 1893 as a four-stroke engine, initially, as formulated in the patent, without cooling and externally driven. In these attempts it was not possible to get the engine to run under its own power. Since there was no cooling, only a short operating time was possible without destroying the engine. The direct injection of the fuel caused difficulties, because with the technology of that time it was not yet possible to produce injection pumps with the required accuracy. Therefore, Diesel changed the injection method . Petroleum was then blown into the cylinder with compressed air at the time of ignition . Compressed air was later used on ships to start diesel engines .

The second engine in 1894

The water-cooled second motor turned under its own power for the first time in 1894. However, many attempts, calculations and design changes were required before the machine was ready for operation.

The third engine in 1897

In 1897 Diesel was able to demonstrate its third engine to a larger group of interested parties. Professor Schröter from Munich examined the engine on the test bench and determined an output of 18 hp (13.1 kW) at 154 revolutions per minute. The fuel consumption was 238 g / PSh (324 g / kWh). With this specific fuel consumption , the diesel engine undercut all heat engines built up to that point .

With the help of Krupp and MAN, Diesel succeeded in creating the most economical heat engine of its time. Both manufacturers, especially MAN, have long been at the forefront of the development of marine diesel engines . Even today, MAN, with its numerous patent holders, is one of the leading competitors in marine diesel engine construction.

Implementation in shipping

Junkers engine ideas prevailed in shipping (Doxford) and in aviation (Jumo 205)

Despite the convincing advantages, shipping circles were very reluctant to use the new technology; they waited for proof of its effectiveness - and rightly so, because there were to be many setbacks in further development. Worldwide, however, diesel engines have now been built and further developed by licensees . The diesel engine, successfully tested in 1897, enabled compact propulsion systems compared to steam propulsion, which were tested on river and seagoing vessels from around 1900 , but initially without success. On the Vandal and the sister ship Sarmat , both Russian river tankers, the diesel engine proved itself as early as 1902/1903. The 1100-ton tanker Vandal had three non-reversible diesel engines, each with 120 HP (88 kW) from the Swedish manufacturer Aktiebolaget Diesel Motorer , which were arranged amidships and which could also drive backwards with electric traction motors based on the del Proposto principle .

Of course, a lot happened at the place where the engine was born, the MAN plant in Augsburg, as well as at Krupp, but also at Deutz and Sulzer . In terms of construction, the open frames, which were modeled on the steam piston engine, had in some cases already gone over to the closed motor housings, with the simultaneous introduction of pressure circulation lubrication of the engine bearings. In 1908 MAN and Blohm & Voss formed a study group to develop a slow-running, double-acting two - stroke engine for the merchant marine , as innovative shipowners showed a need here. This resulted in Fritz in 1915 , the first merchant ship with double-acting two-stroke diesel engines. In addition, an attempt was made to arouse interest in this engine type at the Reichsmarineamt (RMA).

Process, types and charge exchange

The liner Prinzregent Luitpold was to receive the 12,000 hp diesel engine as a medium engine

The first plunger piston engine , i.e. without a crosshead, was built at MAN in 1901 . A distinction is made between cross head, plunger piston and opposed piston engines with and without cross head. The opposed piston engine co-developed by Junkers was later further developed by Doxford into a proven main engine for ships . The opposed piston engine was only built as a two-stroke engine in ships, with or without a crosshead, later even without a crankshaft as a Junkers free-piston air compressor or, according to the patent of Raúl Pateras Pescara, as a Modag free-piston propellant gas generator for gas turbines.

The valves for the gas exchange , the fuel injection and the starting were controlled by cams, the main engines could be reversed by moving the cams; Sulzer from 1906, MAN from 1907. The two-stroke engines required an overpressure of the scavenging air for the gas exchange, which was generated by attached pumps. In addition, one went from the original longitudinal flushing through inlet flushing valves in the cylinder cover and outlet slots in the cylinder liner largely to pure slot control by the working piston, z. B. Sulzer 1909 for cross flushing, MAN for reverse flushing . Here only the starter and fuel cams were reversed. The fuel was transported unchanged into the cylinder by blowing compressed air into it, the pressure of which was usually generated by a three-stage attached compressor of around 60 bar.

Diesel engines for battleships of the German Imperial Navy

In the development of practical submarines, the drive played a decisive role. The diesel engine as a 4-stroke engine (MAN) or as a 2-stroke engine ( Krupp Germaniawerft ) was able to prove its advantages and replaced all other primary drives (steam, compressed air, gasoline engine , petroleum engine ). While the cylinder output in 1901 was 30 hp (22 kW), MAN engines already achieved 200 hp (147 kW) in 1909. At that time, the Reichsmarineamt showed great interest in low-speed engines with 2,000 hp (1470 kW) per cylinder. With six cylinders, this engine should produce 12,000 hp (8,820 kW).

Double-acting two-stroke engines with 2,000 hp per cylinder

At MAN-Nürnberg, Anton von Rieppel had declared a double-acting two - stroke machine with the extremely high output of 12,000 hp to be feasible, as had the engine builders at Krupp-Germania shipyard.

MAN plant in Nuremberg

MAN Nuremberg test engine SN 1200/6 with 12,000 hp fully assembled in 1914

After preliminary discussions with the RMA, the MAN plant in Nuremberg had a. The engineers Rudolf Veith and Wilhelm Laudahn were involved and received the order for this test engine from the naval management in 1910. Initially, it was to be built and tested as a three-cylinder engine with a piston diameter of 850 mm and a stroke of 1050 mm. As a six-cylinder engine, it was then to serve as an economical medium-sized engine for the planned liner SMS Prinzregent Luitpold . This work was started in Nuremberg in March 1910 on a three-cylinder machine, and after several changes to the construction of the working cylinder, the thermal stresses were controlled. Again and again, the high loads led to cracks or breaks. In a serious accident in January 1912, ten Rieppel employees lost their lives and 14 were seriously injured. The construction of the engines was very complex. Each of the upper and lower cylinder covers had four fuel and four purge valves, which were mechanically operated by four control shafts. The two compressed air-controlled starting valves in the upper and lower cylinder covers also functioned as a safety valve . The Nuremberg six-cylinder engine ran for the first time in February 1914 and was carefully loaded with 10,000 hp until September.

The fuel was brought in with air that was blown in by a three-stage 600 HP compressor , which also provided the starting air. The horizontally arranged fuel valves and plate atomizers resulted in insufficient combustion in the power range around 10,000 HP. The results with the sleeve atomizer were considerably better, the color of the exhaust gas decreased and the performance increased with lower fuel consumption.

Meanwhile the First World War had begun, gas oil soon became scarce and the experiments were made more difficult by the use of coal tar oil in combination with ignition oil . The preliminary tests required for this were carried out on a single-cylinder test engine, which ran for the first time in April 1915 and in May for 72 hours with 2,130 hp with tar oil . The conversion of the six-cylinder engine to tar oil then lasted until 1917. On March 24, 1917, the power of 12,200 hp at 135 rpm was driven for twelve hours and the main acceptance took place at the end of March. The engine consumed 214 g / PSh tar oil and 29 g / PSh ignition oil. The engineering achievement was hardly appreciated because of the war, other heroic deeds were meanwhile in the foreground.

Krupp-Germania shipyard

Friedrich Alfred Krupp (1854–1902) in 1900
Krupp Germaniawerft, single cylinder test engine for 2000 HP

In May 1911, the Krupp-Germania shipyard received an order from the RMA for a three-cylinder machine with 6,000 hp (4410 kW), a piston diameter of 875 mm and a stroke of 1050 mm, which was intended as a test machine. After successful testing, it was then to be expanded as a six-cylinder engine with 12,000 hp. The Germania shipyard, however, had already started with a single-cylinder engine of the same dimensions on its own initiative. At the Krupp-Germania shipyard, the flushing and fuel valves were operated hydraulically with castor oil . The cylinder construction was completely changed after first attempts. Cracks required a third and fourth construction. Then you let the flush valves off and went by the DC on the cross flushing. Here you could replace the valves with slots. For the most complete flushing possible, the piston rods were now given deflector surfaces that influenced the flow. After initial trials with a single-cylinder machine, the three-cylinder machine was ready for bench tests in July 1912. In May 1914, a cylinder output of 1760 hp (1293 kW) at 150 rpm was achieved, the pistons could not withstand higher loads. Therefore new pistons were designed and the bronze hood was replaced by a cast steel hood. This enabled 1,800 hp (1323 kW) per cylinder and the naval management granted permission to expand it as a six-cylinder machine, which was completed in August 1916. In May 1917, 10,600 hp (7791 kW) were driven at 140 rpm during a five-day endurance test; for one hour, 12,060 hp (8864 kW) were achieved at 150 rpm. Similar to the MAN machine, the achievements of the engineers , technicians and test personnel involved in this success were hardly appreciated, because the war was now almost lost. The Navy had other worries, the machines were largely scrapped and so the 12,000 hp machines were quickly forgotten.

See also

literature

  • F. Romberg: About ship gas machines . In: Yearbook of the Shipbuilding Society , No. 11/1912, p. 437
  • G. Bauer: Ship engineering , 3rd and 4th volume. R. Oldenbourg, Munich / Berlin 1941
  • F. Sass: History of German internal combustion engine production from 1860 to 1918 . Springer Verlag, 1962.
  • K. Bösche, K.-H. Hochhaus, H.Pollem, J. Taggesell: Steamers, Diesel and Turbines - The World of Ship Engineers . Convent Verlag, Hamburg 2005

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