Two-stroke diesel engine

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Charge exchange in a auslassgesteuerten two-stroke diesel engine
One of the largest German trucks with a diesel two-stroke engine was the Krupp Titan
Diesel two-stroke engine of a Krupp "Elch"

A two-stroke diesel engine is one of the two-stroke principle working diesel engine .

In large diesel engines, the fresh air is through inlet slots (, ports' ) in the lower region of the liner is blown and the exhaust gases via the exhaust valves ejected in the cylinder head. This creates a gas flow from 'cold' to 'hot' and thus a better thermal efficiency. The excess pressure in the fresh air is usually generated by a turbocharger - more rarely a Roots charger .

Two-stroke diesel engines are used as marine engines , and in the past also in trucks, locomotives, agricultural machinery and aircraft. Well-known examples of this are the two-stroke diesel engines of the 53, 71, 92, and 149 series from Detroit Diesel Corporation (DDC), the DR series V 200 locomotive known as the "Taiga drum" , and the opposed piston engines from Junkers ( Jumo 205 ) and Napier ( Napier Deltic ).

Marine diesel

Marine diesels used in large cargo ships are mostly low-speed two - stroke diesel engines. In-line engines are common, preferably with an odd number of cylinders of up to twelve cylinders. Typical dimensions of such engines are bores of up to one meter, a stroke of up to three and a half meters and a nominal speed of 60–80 min −1 with low geometric compression ratios (only about 6: 1 to 8: 1).

These motors are designed with a cross head in the crank drive for low speed in order to drive the propeller directly without coupling and gearbox, which saves costs, installation space and loss of efficiency of gearboxes. You do not need a motorized starter, as they are started by compressed air for forward or reverse rotation. Such engines achieve an efficiency of up to approx. 55% (e.g. MAN G90ME-C10 ), which no other engine type among heat engines can achieve. Due to their huge dimensions and heavy components, marine diesel two-stroke engines are usually built under license directly at the shipyards and not in a central engine production facility. The largest engines are built in Korean and Chinese shipyards.

A typical fuel for these engines is heavy oil , which is obtained from crude oil as residual oil during atmospheric distillation . In its normal state, this heavy oil is as viscous as axle grease and must first be heated to temperatures of 30 - 40 ° C in heating devices on the floor of the fuel bunker before it becomes sufficiently thin and thus pumpable to allow it to be heated to around 130 - 140 after further heating in the end preheaters ° C to be injected into the cylinder heads for combustion.

Agricultural tractor

Hanomag Griffin

After the Second World War, Hanomag , the market leader for agricultural tractors in Germany at the time, tried to establish the two-stroke diesel engine in small haulers such as the Hanomag R12 . The engines of the Hanomag 611 (single-cylinder) and 621 (two-cylinder) series were slot-controlled with Roots flush fans and developed 12 or 24 hp (8.8 or 18 kW). However, Hanomag was unsuccessful in the shrinking market for small tractors : Because of the low power and numerous engine problems, farmers soon decried as a "farm moped" , these tractors contributed to Hanomag's economic decline. In 1962, the "C 115 Greif" was the last Hanomag tractor with a two-stroke diesel engine.

Between 1954 and 1958 , the tractor manufacturer Normag equipped small tractors of the "Kornett" series with a self-designed and built 1.28-liter single-cylinder two-stroke diesel engine with outputs between 12 and 18 hp (8.8 and 13 kW). These engines were also slot-controlled, flushing was carried out with a piston pump (“flushing piston”) operated via a connecting rod .

The engines with direct injection from Heinrich Lanz AG , known as semi-diesel engines , do not use the diesel method with compression ignition , but use the high temperature of the cylinder head as an ignition aid and are therefore direct-injection hot-head engines .

Aircraft engines

In the 1930s there were a few two-stroke diesel opposed piston aircraft engines such as the Jumo 205 and 207 (list here ), as well as others in the experimental stage with direct injection with air storage .

Two-stroke diesel engines for aircraft are offered, for example, by DeltaHawk Engines or Zoche Aero-Diesel (Munich).

railroad

Two-stroke diesel engines have been used in numerous rail vehicles. This includes all locomotives of Class 55 of the British Rail with Napier Deltic engine , a three-row opposed piston engine with three crankshafts at the corners. In addition, two-stroke diesel engines were widely used in diesel-electric locomotives in the United States, with EMC engines being used for decades, for example in the F7 series . Even in European locomotives, such as the Vossloh Euro 4000 , which is mainly used for the Portuguese Takargo Rail , an EMD V16 two-stroke diesel engine was installed.

Flushing and charging

See also gas exchange in a two-stroke engine . Newer two-stroke diesel engines are usually charged , usually with exhaust gas turbochargers . Such engines have an asymmetrical control diagram , which means that the inlet closes later than the outlet so that the boost pressure can build up. For starting up or when the turbocharger's delivery rate is insufficient in partial load operation, there are auxiliary fans, which are usually electrically driven.

In the past, various manufacturers of uncharged two-stroke diesel engines used Roots blowers for flushing, for example Commer in the TS-3 opposed piston engine , Krupp in the engine of the Titan , or Napier, Detroit Diesel and Cummins . The Roots blower was driven mechanically by the engine. There were also engines with crankcase flushing , for example from Fichtel and Sachs .

advantages

Two-stroke diesel engines have a good power-to-weight ratio . Due to the few moving components, they are less prone to failure and therefore have a long service life. Since only minor environmental regulations apply at sea, they are preferred as marine diesel engines with heavy oil as fuel.

disadvantage

These types of engines produce high levels of pollutant emissions in their exhaust gases . Therefore, the uncontrolled (valveless) two-stroke diesel engine in the automotive sector (similar to the two-stroke gasoline engine) could not establish itself despite its simple design.

(former) manufacturer

See also

literature

  • Richard van Basshuysen, Fred Schäfer: Handbook Internal Combustion Engine Basics, Components, Systems, Perspectives. 3rd edition, Friedrich Vieweg & Sohn Verlag / GWV Fachverlage GmbH, Wiesbaden 2005, ISBN 3-528-23933-6 .
  • Peter Gerigk, Detlev Bruhn, Dietmar Danner, Jürgen Göbert: Automotive engineering. 3rd edition, Westermann Schulbuchverlag GmbH, Braunschweig 2000, ISBN 3-14-221500-X .
  • Development status of two-stroke diesel engines for motor vehicles. In: Motor Vehicle Technology 5/1953, pp. 135–141; 6/1953, pp. 174-180; 11/1953, pp. 335-340 and 12/1953, pp. 374-376.
  • The more recent development of the glow head motor. In: Motor Vehicle Technology 9/1954, pp. 264–268.
  • Development work on a short-stroke two-stroke diesel engine KZD 12.4. In: Motor Vehicle Technology 12/1954, pp. 356-360 and 5/1960, pp. 165-168.
  • Development work on the two-stroke diesel engine NZD 12.5. In: Motor Vehicle Technology 10/1955, pp. 342–347, 11/1955, pp. 381–386, 5/1958, pp. 164–167 and 6/1958, pp. 210–214.
  • Is the two-stroke diesel engine gaining ground in motor vehicles? In: Motor vehicle technology 1/1957, pp. 3–6 (including Ford trucks).
  • Operating results of a modern two-stroke diesel engine. In: Motor Vehicle Technology 9/1959, pp. 357–361.
  • The lance Triumph two-stroke diesel engine LT 85 D . In: Motor vehicle technology 1/1960, pp. 4-7 and 2/1960, pp. 46–51.
  • The Ford AD6 two-stroke diesel engine . In: Motor Vehicle Technology 4/1960, pp. 129-136.

Web links

Commons : Two-Stroke Diesel Engines  - Collection of pictures, videos and audio files

Individual evidence

  1. ↑ Konrad Reif (Ed.): Fundamentals of vehicle and engine technology . Springer Fachmedien, Wiesbaden 2017, ISBN 978-3-658-12635-3 , Fields of application of diesel engines / engine characteristics, Table 1: Comparative data for diesel and gasoline engines .
  2. ↑ MAN G90ME-C10 IMO Tier II and III 2015
  3. ^ Contemporary Normag prospectus
  4. ↑ Udo Paulitz: Tractor classics: the most beautiful historical tractors in Germany , Geramond, Munich, 2008, ISBN 9783865170910 . P. 131
  5. ↑ Patent DE938688 : Hot-head motor. Registered on February 2, 1956 , published on May 31, 1952 , applicant: Heinrich Lanz AG, inventor: Anton Lentz. ‌
  6. ↑ [1] (English)
  7. ↑ Brons 2-stroke marine diesel (detailed drawing)
  8. ↑ Rootes multi-fuel diesel engine . In: Motor vehicle technology 9/1960, pp. 365-367.
  9. ↑ a b Technical data / profiles ( Memento from September 4, 2009 in the Internet Archive )
  10. ↑ LM Shugurow: АВТОМОБИЛИ России и СССР. First and second part. Ilbi / Prostreks, Moscow 1993/94, ISBN 5-87483-004-9 and ISBN 5-87483-006-5 .
  11. ↑ Jung two-stroke from Feldbahn ( Memento from January 15, 2014 in the Internet Archive ) (accessed January 14, 2014)
  12. ↑ here a 20 hp 2-T diesel from Jung ( Memento from January 16, 2014 in the Internet Archive )