OM 651 – the first 4-cylinder diesel engine in a limousine
In 2009, Mercedes used a 4-cylinder diesel engine in an S-Class limousine for the first time in history. It was OM 651 Engine introduced by Mercedes-Benz in 2008. The engine set a new standard in terms of efficiency, fuel consumption, exhaust emission, and smooth working. It met EURO V and later EURO VI standards. OM 651 was designed in such a way so that it was possible to produce engines of different power from one capacity and to use them both in rear- and front-wheel drive cars.
All versions included fourth-generation common rail injection, high- and low-pressure turbocharger, improved combustion chambers, variable turbine geometry, and two Lanchester balancer shafts, which ensured balanced work culture in a unit with 2143 cm3 capacity. 204 hp type of OM 651 DE 22 LA was used in two ground breaking Mercedes models.
The first was S 250 CDI BlueEFFICIENCY (W 221 MOPF) which pioneered the use of four-cylinder engines in this car segment. The second model was E 300 BlueTEC Hybrid (W 212), in which a diesel engine equipped in BlueTEC technology was combined with an electric engine for the first time.