Mercedes-Benz V-6 engines are not long for this world, but it's not all bad news. Ola Källenius, head of Mercedes research and development, did confirm the brand will phase out V-6 engine, but it means a return of the inline-6.

Road & Track reported on Källenius' comments on Tuesday after a roundtable interview at the 2018 Detroit auto show. The strategy behind new inline-6s and the V-6's retirement surrounds a shift to more inline-4 powered vehicles. The inline-6 and inline-4 are natural partners, just like the V-8 and V-6 engine were for decades, the R&D chief said.

Källenius said Mercedes-Benz's inline-4 and 6 engines "are branches of the same tree," and they can be built on the same production line. The silky smooth operation of the 6 is but a cherry on top, he added.

The German luxury brand showed its first inline-6 engine, dubbed the M256, displacing 3.0-liters in 2016. The engine features a 48-volt mild-hybrid system with an integrated starter generator. The unit replaces the standard starter and generator with a single more powerful unit placed between the engine and transmission sans belts. The design also helps overcome one of the inline-6's downsides: its overall length. 

The ISG can also add a 20 horsepower and 162 pound-feet of torque boost during high-load situations, and Mercedes-Benz proclaimed it will offer V-8-like performance with 6-cylinder efficiencies. 

Although the brand is all-in on inline-6 engines, the change won't happen overnight. Road & Track also reported there are no plans to place the engine in the C-Class, but the United States market will see the engine in a new E53, CLS450, and CLS53. But the best may be yet to come. Last year, Mercedes-AMG announced it too has an inline-6 based on the M256 in the works. We can't wait to see how much power that engine will produce and in what vehicles it will be used.