The Mercedes-Benz E-Class, now in its fifth generation, is due for a refresh soon, and Mercedes has lifted sheet, so to speak, cluing us in on what's next for the mid-size luxury sedan in a new video. The car it's chosen to show is just a prototype, debadged and still wearing a bit of camouflage, but it looks to be ready to go, so there shouldn't be too many surprises when Mercedes finally debuts the car for real as a 2021 model.

The updated car's piece de resistance is a new four-cylinder engine with an integrated starter-generator - part of a 48-volt mild-hybrid system that will help accomplish greater fuel efficiency.

Unfortunately, Michael Kelz, Chief Engineer for the Mercedes-Benz E-Class, is tight-lipped in the video about the new four-cylinder's specifics. The 2021 E-Class will be this engine's first application, where it will be offered alongside Mercedes's M256 inline-six from the CLS. That engine also uses a starter-generator, as part of a 48-volt mild-hybrid system that leverages an auxiliary air compressor to spool the turbocharger up for reduced lag.

Just as important, the plug-in-hybrid E-Class appears destined to solider on, although it's unknown whether it will feature any significant mechanical changes from the current version. Kelz remarks in the video that hybrids will "play a major role in the future, both as petrol and diesel variants," so we expect to see both make an appearance in the 2021 model line and beyond - although not necessarily in every market.

Otherwise, the biggest changes coming to the Mercedes-Benz E-Class are primarily visual, with new headlight and taillight designs, a massaged exterior appearance, and inside, a completely reworked steering wheel - something that Kelz calls the "defining new feature of the interior of the Mercedes-Benz E-Class.

But the E-Class's tech will receive some welcome improvements, as well, the 2021 model benefitting from a gesture control system that can actually differentiate between commands issued by the driver or front-seat passenger, and an improved automatic parking system that might work even faster than a human driver, Kelz says.

The newly refreshed Mercedes-Benz E-Class will debut officially online next week, following the cancelation of the 2020 Geneva Motor Show.