Mercedes-Benz OM 86
The 12-cylinder four-stroke diesel engine Mercedes-Benz OM 86 was a high-speed diesel engine from Mercedes-Benz for installation in fast railcars of the Deutsche Reichsbahn . The engine was used for the first time in 1937 and was designated the MB 806 from 1938 . Five copies of it were installed in pre-war railcars and were the further development of the Mercedes-Benz OM 85 . The increase in performance compared to these engines was achieved by increasing the cylinder diameter. Compared to the diesel engines from Maybach-Motorenbau and MAN , which are predominant in railcar construction, the engines had some design changes. After the Second World War , 12-cylinder four-stroke diesel engines in diesel railcars, including the Mercedes-Benz MB 836 series , became known.
Structure and components
Basic structure
The engine is naturally aspirated and has a pre-chamber injection of the fuel. It consisted of a crankcase made of silumin , three cylinders from each engine were cast as a cast piece from gray cast iron and screwed to the crankcase. The two rows of cylinders, arranged in a V-shape, faced each other without any offset. In contrast to the Maybach GO 5 , fork-shaped connecting rods were used on the right side of the OM 86 . Three cylinder heads are also combined in one cast block. The cylinder liners were made of cast iron and individually interchangeable.
The crankshaft had seven bearings in the crankcase. It was case hardened . In two engines, the crankshafts were made of nitrided steel, which cost three times the price of conventionally manufactured crankshafts. The bearing in the crankcase was designed in plain bearings . The Thermodur bearings (with a support shell made of steel and cast bronze) were primarily used for the bearing of the crankshaft in the housing and for the bearing of the connecting rods on the crankshaft, so-called Admos bearings were used for the two motors with crankshafts made of nitrided steel ( Pin bearing with cast bearing running layer) is used. The connecting rod bearing with the piston was the usual one-piece bronze bushing.
There were also variants in the choice of piston. At first, those made of light metal were used, later, during the scheduled maintenance in the repair shop, those made of forged material were used.
Fuel system and engine control
The engine works on the prechamber principle of fuel injection. A separate diesel injection pump was used for each cylinder side ; they were manufactured by Bosch and were arranged one behind the other in the V of the engine. Both injection pumps had a common injection adjuster that was inserted between the pump drive wheel and the first pump. The engine governor and injection pump were operated via a bevel gear drive from the camshaft drive . The motor was controlled according to the principle of speed regulation in five stages. The glow plugs used for preheating were supplied by their own 12 V network, which was fed by its own generator. The alternator worked on a backup battery and was arranged transversely on the diesel engine; it was driven by the output of the camshaft.
The diesel engine was operated with speed control in five stages. The associated speed controller was electrically driven.
Cooling, lubrication and air system
The engine was water-cooled. The cooling system was arranged in the machine bogie and under the floor in the usual way at the time.
Like all large diesel engines , the engine was operated with pressure circulation lubrication ; the pressure oil was delivered by two single-stage gear pumps .
Technical specifications
| Parameter | unit | value | comment |
|---|---|---|---|
| rated capacity | kW | 331 | 450 hp |
| Rated speed | min -1 | 1,400 | |
| Idle speed | min -1 | 600 | |
| Number of cylinders | 12 | ||
| Cylinder diameter | mm | 165 | |
| Piston stroke | mm | 195 | |
| Stroke volume | l | 50 | |
| mean piston speed | m / s | 9.1 | |
| medium work pressure | bar | 5.6 | |
| Injection pressure | bar | 95 | |
| highest ignition pressure | bar | 58 | |
| Fuel consumption | g / PSh | 200 | at full load |
| Compression ratio | 17th | ||
| Engine ground | kg | 2,500 | with accessories |
| Motor length | mm | 1,964 | |
| Engine width | mm | 1,240 | |
| Engine height | mm | 1,554 | |
| Procurement price | Reichsmark | 43,176 |
Vehicles equipped with the engine for delivery
The three railcars VT 137 188 to 190 and the two VT 137 286-287 were equipped with this engine from the factory. Other engines were not known until after the Second World War with the successor model, the Mercedes-Benz MB 836 .
Operating experience
For the engines mentioned in the literature, there is no information in the literature on their reliability and mileage. The two Ruhr railcars ran next to nothing at all until the end of the war, and no information is available about the standard railcars. At least two of them achieved a service period until 1965 with the DB and until 1976 with the DR of the GDR . The documents do not indicate with which engines. The DB vehicle is known to have been used in a railcar circuit on the express train from Frankfurt am Main to Regensburg (342 km), alternating with railcars DR 137 271 and 272 on this route.
literature
- Heinz R. Kurz: The railcars of the Reichsbahn types. EK-Verlag, Freiburg 1988, ISBN 3-88255-803-2 .
Individual evidence
- ↑ a b Heinz R. Kurz: The railcars of the Reichsbahn types. EK-Verlag, Freiburg 1988, ISBN 3-88255-803-2 , p. 311.
- ↑ Heinz R. Kurz: The railcars of the Reichsbahn types. EK-Verlag, Freiburg 1988, ISBN 3-88255-803-2 , p. 301.
- ↑ Heinz R. Kurz: the railcars of the Reichsbahn types. EK-Verlag, Freiburg 1988, ISBN 3-88255-803-2 , p. 375.
- ↑ Data sheet of the VT 137 190 at www.roter-brummer.de
- ↑ Data sheet of the VT 137 189 at www.roter-brummer.de
- ↑ Heinz R. Kurz: The railcars of the Reichsbahn types. EK-Verlag, Freiburg 1988, ISBN 3-88255-803-2 , p. 351.
| Timeline of the Daimler-Benz diesel engines up to 1945 | |||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Number of cylinders | design type | Displacement (l) | 1920s | 1930s | 1940s | ... | |||||||||||||||||||||||
| 0 | 1 | 2 | 3 | 4th | 5 | 6th | 7th | 8th | 9 | 0 | 1 | 2 | 3 | 4th | 5 | 6th | 7th | 8th | 9 | 0 | 1 | 2 | 3 | 4th | 5 | ||||
| 1 | Lying | 3.4 | OE engine | ||||||||||||||||||||||||||
| 4.2 | OE engine | ||||||||||||||||||||||||||||
| 2 | In-line engine | 5.7 | S6 engine | ||||||||||||||||||||||||||
| 4th | 2.6 | OM 138 | |||||||||||||||||||||||||||
| 3.8 | OM 59 | ||||||||||||||||||||||||||||
| 4.9 | OM 65 | ||||||||||||||||||||||||||||
| 8.8 | OB 2 | ||||||||||||||||||||||||||||
| 6th | 7.3 | OM 67 | |||||||||||||||||||||||||||
| 7.4 | OM 67 | ||||||||||||||||||||||||||||
| 8.6 | OM 5 | ||||||||||||||||||||||||||||
| 10.3 | OM 79 | ||||||||||||||||||||||||||||
| 11.3 | OM 57 | ||||||||||||||||||||||||||||
| 12.5 | |||||||||||||||||||||||||||||
| OM 54 | |||||||||||||||||||||||||||||
| 12 | Boxer engine | 30.2 | OM 807 | ||||||||||||||||||||||||||
| V engine | 30.5 | OM 85 | |||||||||||||||||||||||||||
| OM 86 | |||||||||||||||||||||||||||||
| Legend: | Benz engines | Daimler-Benz engines | |||||||||||||||||||||||||||