https://www.autocar.co.uk/car-news/n...ybrid-four-pot
My thoughts on the article:
Based on comments made by Tobias Moers a couple years ago, it has been clear that the next generation of AMG vehicles in the Mercedes "C" family will ditch the V8 for a hybrid setup with fewer cylinders and less displacement.
However, the M256 inline six seemed like the most natural choice (to me, anyway) since it was designed from the start as a hybrid engine (ISG) for RWD applications and would apparently only need minimal attention to be upgraded from the middle tier seat it occupies in Mercedes "E" family of *53 vehicles at 430hp to a top tier seat in their "C" family with presumably 500hp+.
But now it appears the new M139 four cylinder may have been given the nod instead. This means it will gain an ISG setup like the M256 already has, and also be reoriented for longitudinal configuration. If true, this move is surprising for a couple reasons. First, the M139 is a very high strung engine, while the M256 has lots of room for growth - potentially to 600hp and beyond which is where the S58 will likely be heading by the middle of next decade (with the addition of a mild hybrid setup of its own, no doubt). Moreover, the perception here is going to be interesting for Mercedes to manage because their performance seeking clientele has traditionally been drawn in at least in part by higher displacement and cylinder counts than competitors.
I would have been completely convinced if the plan were described as a move to an I4 hybrid for the *43 vehicles while the *63 tier (perhaps with a new name, like *55) moved to the I6 hybrid. But the elimination of all engines with more than four cylinders across the whole lineup is a bit difficult to accept, even as electrification becomes more and more pervasive in performance applications.