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Langhuber is a term from internal combustion engine construction and describes an engine whose piston stroke is greater than the cylinder bore , the so-called stroke ratio is then greater than 1.

Langhuber have a lower maximum speed and thus a lower maximum output. Four-stroke long-stroke engines have smaller inlet and outlet valves. However, they have compact and therefore thermally efficient combustion chambers. Valve-controlled two-stroke long-stroke engines (see below) have lower fuel consumption than short -stroke engines . The lower maximum speed and thus the lower power density may be disadvantageous. For problem-free lubrication , the top piston speed is 20 m / s.

The petrol engine with probably the largest stroke ratio ran in the racing Voiturette VX5 from Peugeot around 1910: the two-cylinder with 2815 cm³ displacement had a cylinder bore of 80 mm and a piston stroke of 280 mm (stroke ratio 3.5: 1). The cause was a competition regulation, which stipulated the cylinder bore at 80 mm without limiting the stroke. The Ventoux with 603 cm³ from the Renault 3 with a cylinder bore of 49 mm and a piston stroke of 80 mm should have the largest stroke ratio of 1.63 among the engines of series passenger cars. The Willys Go Devil four-cylinder with a cylinder bore of 79.4 mm and a piston stroke of 111.1 mm is also designed with a long stroke of 1.40. A car with a moderately long-stroke gasoline engine was the Mercedes A 200 (100 kW / 136 PS).

In large, slow-running two-stroke marine diesel engines , the maximum speed is limited to around 60 to 120 rpm due to the risk of cavitation (vapor bubble formation) on the directly driven propeller. This results in very long strokes despite low mean piston speeds. For example, the Wärtsilä-Sulzer RTA96-C has a cylinder bore of 960 mm and a piston stroke of 2500 mm (stroke ratio 2.60: 1). Its successor, the X92, has a cylinder bore of 920 mm and a piston stroke of 3468 mm (stroke ratio 3.77: 1). The medium-speed oil and gas powered MAN 2-stroke engine 5G45ME has cylinders with a bore of 450 mm and a stroke of 2250 mm (stroke ratio 5: 1).

Individual evidence

  2. Richard v. Frankenberg / Marco Matteucci: History of the Automobile (1973), Sigloch Service Edition / STIG Torino; P. 164.


  • Max Bohner, Richard Fischer, Rolf Gscheidle: Expertise in automotive technology. 27th edition, Verlag Europa-Lehrmittel, Haan-Gruiten 2001, ISBN 3-8085-2067-1 .