Mercedes-Benz MB 518
The Mercedes engine of the MB 518 series is a diesel engine for driving fast government and marine boats as well as motor yachts.
development
The MB 518 was built in the 1940s as the MB 501 almost exclusively for use in speedboats and was a further development of the airship engine LOF 6, which also served as a drive for the airship Hindenburg . In 1951 this high-performance engine was produced again and initially only exported. The engines were then installed in several speedboat classes by the German Navy and exported to more than 35 countries in Europe, America, Africa and Asia.
Technical specifications
The engine is a high-speed 20-cylinder four-stroke diesel engine with a cylinder angle of 40 degrees and a displacement of 134.4 liters. The two-part motor housing is cast from a seawater-resistant aluminum alloy , both parts are screwed together with tie rods . The crankshaft is forged and runs in eleven double-row rolling bearings which, apart from the bearing, are divided into eleven due to their design. The engine oil collects in the lower part of the housing and is pumped from there into the oil collecting tank ( dry sump lubrication ). The engine is started and reversed with compressed air, the supercharger is driven mechanically. A planetary gear with clutch is attached to the power-emitting side . The reduction is 1.72: 1. With an engine weight of 4800 to 5390 kg, the power-to-weight ratio was around 1.5 kg / hp.
The cylinders consist of a cylinder head , cylinder liner and cooling water jacket and are used as a unit in the upper part of the housing. In the cylinder head, two inlet and outlet valves are arranged around the central prechamber . The inlet valves are provided with rotocaps . The two camshafts located on the side of the engine housing are on roller bearings and can be shifted for reversing. They operate the valves via roller tappets, push rods and rocker arms. Air intake valves are built into 18 cylinder heads. The main connecting rods are designed as fork connecting rods and run with the secondary connecting rods in plain bearings. The light alloy pistons have two oil control rings and three piston rings.
The gear case is attached to the front of the engine. From there the two camshafts, two cooling water pumps , four injection pumps , two fuel feed pumps, the injection timing adjuster, the oil pressure-controlled regulator, the engine oil pumps and the seawater pump are driven. The sea water pump feeds several cooling circuits; for the engine cooling water (fresh water), the engine oil and in versions C and D for the charge air.
variants
| Daimler Benz | |||
|---|---|---|---|
| 1951-1973 | |||
| diesel | |||
| engine | MB 518 | ||
| Executions | B. | C. | D. |
| MTU | MB 20V 672 M | MB 20V 672 T | |
| Dimensions | 4800 to 5390 kg depending on the version | ||
| L × W × H | 4520 mm × 1581 mm × 2420 mm | ||
| Construction year | from 1966 | from 1968 | |
| High performance | 2275 hp (1.7 MW)
1720 rpm |
2500 hp (1.8 MW)
1720 rpm |
3500 hp (2.6 MW)
1700 rpm |
| maximum torque | 12 kN m at? / Min | ||
| Mixture formation | Pre-chamber injection | ||
| design type | V20, cylinder bank angle 40 ° | ||
| Displacement | 134.4 l | ||
| drilling | 185 mm | ||
| Hub | 250 mm | ||
| Charging | without | compressor | turbo |
| Intercooler | without | Yes | Yes |
| cooling | water | ||
| Diesel pumps | 4th | ||
| Piston speed | 14.4 m / s | ||
The further developments of the MB 518 are the MB 518 B and MB 518 C (MB 20V 672 M) with mechanical charging fan and the MB 518 D (MB 20V 672 T) with exhaust gas turbocharger . The charging fan ( turbocharger in later versions ) is mounted on the output side. The intercooler is mounted upright above the engine. With the same basic data, the 518 B engines have a continuous output of 2275 HP with a maximum output of 3000 HP for 30 minutes within six hours, the 518 C has a continuous output of 2500 HP with 3000 HP maximum output and the 518 D has a continuous output of 2900 HP 3500 hp maximum output.
swell
- Mercedes-Benz AG brochure on the MB 518 series
- Mercedes-Benz construction instruction for speedboat diesel engine MB 518 B edition A, Stuttgart-Untertürkheim 1958