| Mercedes-Benz OM642 engine | |
| Manufacturer: | Daimler AG |
| Configuration: | 72° V6 |
| Production: | 2005- |
| Predecessor: | Mercedes-Benz OM648 engine |
| Successor: | Mercedes-Benz OM656 engine VM A630 (VM Motori) |
| Bore: | 832NaN2 |
| Stroke: | 922NaN2 |
| Displacement: | 2987cc |
| Weight: | 208kg (459lb) |
| Block: | Aluminium |
| Head: | Aluminium |
| Valvetrain: | DOHC 4 valves x cyl. |
| Turbocharger: | Variable nozzle Garrett GT2056VK, GTB2060VKLR, GTB2260VKLR |
| Fuelsystem: | Common rail direct injection |
| Fueltype: | Diesel |
| Coolingsystem: | Water cooled |
| Power: | European models: 1950NaN0. US vehicles: 1570NaN0. Mercedes/Dodge Sprinter, x280 CDI models: 1400NaN0. Mercedes-Benz G-Class (W461) G280/G300 CDI: 1350NaN0. |
| Torque: | European models: 6200NaN0. US vehicles: 5400NaN0. Mercedes/Dodge Sprinter, x280 CDI models: 4400NaN0.Mercedes-Benz G-Class (W461) G280/G300 CDI: 4000NaN0. |
| Compression: | 18.0:1 |
The Mercedes-Benz OM642 engine is a 29871NaN1, 24-valve, aluminium/aluminium block and heads diesel 72° V6 engine manufactured by the Mercedes-Benz division of Daimler AG as a replacement for the Mercedes straight-5 and straight-6 cylinder engines.[1]
The engine features common rail Direct injection and a variable nozzle turbocharger. The injection system operates at 1600bar, while the compression ratio is 18.0:1. The engine features a counter-rotating balance shaft mounted between the cylinder banks to cancel the vibrations inherent to the 72 degree V6 design, and the crankpins are offset by 48 degrees to achieve even 120 degree firing intervals. In some heavy vehicle applications, Mercedes' BlueTec AdBlue urea injection is utilised for NOx reduction.[2] In lighter vehicle applications, a NOx storage catalyst captures nitrous oxides, which are periodically purged (decomposed) by running the engine slightly rich. A particulate filter lowers soot, making this engine ULEV certified.[3] Engine mass is 208kg (459lb). Power output is 1650NaN0 and 5100NaN0 of torque. For the 2007 model year, torque is raised to 5400NaN0.
At the beginning of summer 2017 the engine, together with Mercedes-Benz OM651 was under investigation by the Federal Motor Transport Authority in respect of the alleged emissions cheating scandal wherein the laboratory emissions testing produced a different amount of diesel exhaust fluid usage and lower emissions than in real world operating scenarios. [4]
Vehicles using this engine include:
Air is drawn into the engine through two air filters located above each cylinder head. The amount of the air is measured by two hot film mass air flow sensors B2/6&7. On Sprinter models, a single air filter housing is mounted upon brackets on top of the engine.
The variable geometry Turbine is actuated via a linkage connecting the controller to vanes inside the Turbine housing. With the VGT vanes in a closed position the exhaust gases is accelerated into the turbine wheel blades increasing shaft speed thereby increasing boost. With the vanes in the open position the exhaust gases are decelerated causing a drop in the shaft speed and consequent drop in boost.