Mercedes-Benz OM 628 / OM 629
| Mercedes Benz | |
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| OM 629 | |
| Manufacturer: | Mercedes Benz |
| Production period: | 1999-2010 |
| Working principle: | diesel |
| Design: | Eight-cylinder V-engine |
| Engines: | 4.0 liters (3996 cm³) |
| Previous model: | none |
| Successor: | none |
The OM 628 and his successor OM 629 are turbo - diesel engines with eight cylinders in V-arrangement and common-rail direct injection , developed and produced by the end of 2010 by Daimler-Benz for use in Mercedes-Benz - cars from the upper middle class.
The abbreviation "OM" stands for "Oel-Motor" (engine that runs on light oil / diesel) and has been used to describe Daimler's diesel engines since production began .
history
The first V8 passenger car diesel engine from Daimler came onto the market in the summer of 2000 in the Mercedes model S 400 CDI of the S-Class (220 series) . In the period that followed, this engine type was also used as the E 400 CDI in the E-Class (W 211) and was used in the G-Class and M-Class SUVs (W 163) . Depending on the model, it developed 184 to 191 kW (250 to 260 hp).
With the OM 628 engine, Daimler-Chrysler was able to catch up with the eight-cylinder diesel offers from competitors Audi ( A8 ) and BMW ( 740d ) that had appeared earlier .
The successor to the market was the OM 629 with a higher output in mid-2005 . The series was discontinued at the end of 2010; Daimler did not pursue the engine concept any further.
Since 2017, Mercedes-Benz has been issuing the model designation 400 d again in the S-Class (222 series) and the E-Class (W 213) , but here with the in-line six-cylinder diesel OM 656 .
OM 628
The OM 628 came onto the market in the summer of 2000 in the Mercedes model S 400 CDI of the S-Class (220 series) .
The engine has an engine block made of sand-cast aluminum in bedplate design (split at the level of the crankshaft) with inserted wet cylinder liners made of cast iron ( centrifugal casting ). Reinforcements of the main bearings made of GGG are cast into the lower part . The bore is 86 mm, the stroke 86 mm. The compression ratio is 18.5: 1. The cylinder spacing is 97 mm. For the angle between the cylinder banks, 75 ° and not 90 ° were chosen due to the installation space, as is usual with V8 engines. This results in first-order free mass forces. To compensate for this, a balance shaft is arranged above the crankshaft in the cylinder V. The crank pins of the crankshaft are split (without intermediate beam) to ensure even firing intervals. For each row of cylinders, the engine has a turbocharger with adjustable turbine guide vanes, two overhead camshafts, and four valves per cylinder that are operated by hydraulic bucket tappets . The charge air is cooled by an air-water heat exchanger with a second, cold water circuit. This has the advantage that the cooler contains a smaller volume of air while still having a lower flow resistance.
The OM 628 with the exact engine designation OM 628 DE 40 LA * was used in the following Mercedes vehicles until 2005:
| Sales description | model series | Construction period |
|---|---|---|
| Displacement: 3996 cm³, power: 184 kW (250 hp) at 4000 rpm, torque: 560 Nm at 1700-2600 rpm | ||
| ML 400 CDI | W 163 | 2001-2005 |
| S 400 CDI | W / V 220 | 1999-2003 |
| G 400 CDI | W 463 | 2001-2005 |
| Displacement: 3996 cm³, output: 191 kW (260 hp) at 4000 rpm, torque: 560 Nm at 1700-2600 rpm | ||
| E 400 CDI | W 211 | 2003-2005 |
| S 400 CDI | W / V 220 | 2003-2005 |
OM 629
With newer CDI technology and higher boost pressure of the two turbochargers, but the same displacement, this engine achieves higher power and torque values. It was also used from mid-2005 in the E- and S-Class sedans and also in the M- and GL-Class under the designation 420 CDI . In the G-Class, the OM 629 was dropped in favor of the V6-CDI OM 642 .
The OM 629 with the exact engine designation OM 629 DE 40 LA * was used in the following Mercedes vehicles until the end of 2010:
| Sales description | model series | Construction period |
|---|---|---|
| Displacement: 3996 cm³, power: 225 kW (306 hp) at 3600 rpm, torque: 700 Nm at 2000-2600 rpm | ||
| ML 420 CDI ML 450 CDI |
W 164 | 2007-2009 2009-2010 |
| GL 420 CDI GL 450 CDI |
X 164 | 2006–2009 2009–2010 |
| Displacement: 3996 cm³, power: 231 kW (314 hp) at 3600 rpm, torque: 730 Nm at 2200 rpm | ||
| E 420 CDI | W 211 | 2005-2009 |
| Displacement: 3996 cm³, output: 235 kW (320 hp) at 3600 rpm, torque: 730 Nm at 2200 rpm | ||
| S 420 CDI S 450 CDI |
W / V 221 | 2006–2009 2009–2010 |
* Engine designation is encoded as follows: OM = oil engine (diesel), series = 3 digits, DE = direct injection, displacement = deciliters (rounded), L = charge air cooling, A = exhaust gas turbocharger
Other uses
The OM 629 is also used as an aircraft engine under the name Thielert Centurion 4.0 .