Mercedes-Benz OM 628 / OM 629 diesel engines

Mercedes Benz
OM 628 OM 629
Manufacturer:	Mercedes Benz
Production period:	1999-2010
How it works:	diesel
Style:	Eight-cylinder V-engine
Engines:	4.0 liters (3996 cc)

The OM 628 and his successor OM 629 are turbo - diesel engines with eight cylinders in V-arrangementand 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 "oil engine" (engine, which is operated with light oil / diesel) and designates since the beginning of production until today the diesel engines of Daimler .

History

The first V8 passenger car diesel engine from Daimler came in the summer of 2000 in the Mercedes model S 400 CDI the S-Class (220 series) on the market. In the aftermath of this type of engine as E 400 CDI wasalso used in the E-Class (W 211) and was used in the off-road vehicle G-Class and M-Class (W 163) . Depending on the model, he made 184 to 191 kW (250 to 260 hp).With the OM 628 engine, Daimler-Chrysler was able to catch up with the previously published offers for eight-cylinder diesels from competitors Audi ( A8 ) and BMW ( 740d ).As a successor in mid-2005, the OM 629 with higher performance on the market. End of 2010, the series was discontinued; The engine concept was not pursued by Daimler.

Since 2017, Mercedes-Benz has again awarded the model designation 400 d in the S-Class (class 222)and the E-Class (W 213) , but here with the inline six-cylinder OM 656 diesel .

OM 628

The OM 628 was launched in the summer of 2000 in the Mercedes model S 400 CDI S-Class (220 series) on the market.

The engine has an engine block made of aluminum sand casting in bedplate construction (divided at the height of the crankshaft) with inserted wet cylinder liners made of cast iron ( centrifugal casting ). Reinforcements of the main bearings made of GGG are cast in 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 usual in V8 engines. As a result, free inertial forces of the first order occur. To compensate for this, over the crankshaft in the cylinder V is a balance shaftarranged. For even firing intervals, the crank pins are the crankshaft divided (without intermediate web). For each cylinder bank, the engine has a turbocharger with adjustable turbine vanes, two overhead camshafts, and four valves per cylinder 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 lower flow resistance.

The OM 628 with the exact engine designation OM 628 DE 40 LA * was used until 2005 in the following Mercedes vehicles:

OM 629

With newer CDI technology and higher boost pressure of the two turbochargers, but same displacement, this engine achieves higher power and torque values. He was also from mid-2005 in E and S-class sedan and also used in M ​​and GL class under the name 420 CDI . In the G-Class, the OM 629 accounted for the V6-CDI OM 642 .

The OM 629 with the exact engine designation OM 629 DE 40 LA * was used until the end of 2010 in the following Mercedes vehicles: