M 256, an abbreviation in principle also for a diesel engine, at Daimler marked with an 'O' for 'Oil motor'. First of all there is the change from V to in-line engine. Interesting in the data above, the significantly smaller cylinder spacing, which shows that a V6 is probably also mathematically a bit longer than an In-line 4 because of its crank mechanism. But since the S-Class also houses V8 engines, there is no problem with an I6.

The I6 has a hot and an equal big cold side, the V6 usually has little room on the cold in the V and splitted space on the two hot sides. Aggregates for exhaust gas purification are therefore easier to accommodate on one side of the R-6. So there is more space under the car floor, eg for battery capacity.

Obviously, the R-6 also makes it easier to expose the rapid heat of the turbo to the exhaust system. There are two less camshafts to drive and it has the more balanced mass. In addition, the manufacturer dispenses with E-air compressor and E-liquid pump on any belt drive. Presumably, it then fits into even shorter engine compartments.

The engine is designed with a clearly longer stroke, a first advantage for more torque. Despite a larger stroke, the length of the connecting rods has shrunk, probably at the expense of the pistons length, which, incidentally, are made from steel. However, the geometric compression is disappointingly low for the Miller process, which was most recently preferred by Daimler. Efficiency seams to be not to have priority.

The beltless drive is praised, but at the same time it is explained that the 48V system was absolutely necessary to apply the 5 kW for the air conditioning compressor. Conversely, much more kinetic energy of the internal combustion engine first has to be converted into electrical energy instead of being transmitted directly via belt drive when the air conditioning is switched on.

The engine is expected in the S-class to have the torque of an eight-cylinder. It can do it justice by a large, twin-bladed turbocharger. It might have have start-up problems at low revs. But a turbo lag is completely avoided by the electric motor on the crankshaft and the additional electric charger. Only missing its electric motor directly on the shaft of the large turbocharger shaft.

A direct driving 48V engine is pretty new. Its modest-sounding performance is rather unimportant, but with 250 Nm, it allows the combustion engine to operate in particularly fuel-efficient parts of the map, sailing is possible, start even more smoothly. As already mentioned, however, efficiency was not widely respected. They do not need it, because the size of the 48V battery allows to reach any CO₂ value. The European hybrid legislation opens the door to more rather than less CO₂ emissions. 06/18