Mercedes-Benz OM 5

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Daimler-Benz AG

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OM 5
Production period: 1928-1932
Manufacturer: Daimler-Benz AG
Working principle: diesel
Motor design: R6
Valve control: OHV
Displacement: 8572 cm 3
Mixture preparation: Pre-chamber injection
Engine charging: no
Power: 44 kW
Previous model: OB 2
Successor: OM 59
OM 65
OM 67

The OM 5 is a diesel engine from Daimler-Benz AG . It was introduced in 1927 as a drive for the L 5 truck; series production started in 1928. The successor models were produced from 1932 onwards.

The OM 5 is a six-cylinder in-line engine. It is a four - stroke diesel engine with pre-chamber injection , water cooling and pressure circulation lubrication and a side, spur gear-driven camshaft and seven crankshaft bearings. Bore and stroke are 105 mm × 165 mm, this results in a displacement of 8572 cm 3 . It delivers 60 hp (44 kW) at 1300 min -1 .

background

The previously competing companies Benz & Cie. and Daimler-Motoren-Gesellschaft had already independently developed truck models in the 5-ton class that were powered by diesel engines. The two companies merged in 1926 to form Daimler-Benz AG , which continued to manufacture trucks. The diesel engine had not yet established itself as a vehicle drive in 1927, the OB 2 engine model from Benz & Cie. for example, it had not been produced in significant numbers. In the new model range of Daimler-Benz AG, the light and medium-weight trucks in the 1.5-ton and 3.5-ton classes were initially only offered with gasoline engines. The L 5 truck in the 5-ton class was initially the only truck from Daimler-Benz that was offered with a diesel engine. The M 36 gasoline engine with 100 hp (74 kW) was also optionally available for this truck.

Compared to the Otto engine, the diesel engine has the disadvantage that its displacement is lower. Truck manufacturers who did not offer a diesel engine in their vehicles benefited from this fact in the 1920s. Their vehicles were more powerful than diesel vehicles with the same cubic capacity. Daimler-Benz AG countered this with the OM 5, which in 1928 was the four-stroke diesel engine with the highest displacement on the German commercial vehicle market. Its performance was 71 hp (52 kW) at 1300 min -1 specified, the capacity is 8572 cm 3 . This development was possible because Bosch began mass-producing a new in-line injection pump in 1928 and the options for calculating engines had improved. The engine achieved an average working pressure of 5.6 bar, which was high for its time. The engine was not able to cope with this, which manifested itself in "unmanageable difficulties" and in "reduced durability of the pistons". Theo Delfried Domina sees this as a thermal overload of the engine. In the series model, the average working pressure has therefore been reduced to 4.74 bar. The nominal power reduced thereby from 71 hp to 60 hp at a speed of 1300 continues min -1 . Advances in diesel engine technology, the rated speeds of more than 2000 min could soon -1 be increased, so that higher power ratings were achieved. The OM 5 was replaced by the OM 59 as early as 1932 . The more powerful models OM 65 and OM 67 are also based on this engine .

swell

  • Olaf von Fersen: A Century of Automotive Technology. Commercial vehicles. VDI-Verlag, Düsseldorf 1987, ISBN 9783662011195 , pp. 128 and 129.

Web links

Individual evidence

  1. ↑ Fersen, p. 129.
  2. ↑ a b Fersen, p. 128.
  3. ↑ 1933: Daimler-Benz presents the new LZ 4000, LZ 6000 and LZ 8000 semi-trailers. - Fast-running diesels are the key to success
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