Mercedes-Benz confirms a new family of engines

Mercedes-Benz finally confirmed it is going to revive the inline six-cylinder aluminium engine. First revealed to Drive at the 2015 Geneva motor show, the German brand used a showcase of its alternative powertrain technology in Stuttgart this week to officially confirm the new straight six will headline a new family of engines.

The new aluminium engines will be built in both four- and six-cylinder configurations and in both petrol and diesel forms. The four-cylinder is expected to be 2.0-litres in capacity and the six-cylinder will be 3.0-litres.

Bernhard Heil, vice president of powertrains for Mercedes-Benz, revealed work began on the new aluminium engine family five years ago with several key targets in mind.

"Having in mind that emissions should be one key element, having in mind that CO2 should be one key element and performance should be one key element," Heil said.

The inline six-cylinder will be rolled out across the Mercedes range in the coming years, eventually replacing the current V6 powerplants. The decision to switch back to an inline configuration was driven by several factors, including packaging inside the car.

But another key reason, according to Heil is the fact all variants can be built in the same factory, which means Mercedes can tailor production to meet market demand. That helps as four-cylinder engines become more popular, reducing the need for a V6 that cannot be shared with an inline four.

"Nowadays the situation is changing a bit," Heil said. "Eight-cylinder volume is more or less stable, six-cylinder volume is more or less stable [but there is an] increase in four-cylinder volume. That's why we said it makes sense to combine four and six-cylinder aluminium engines."

The move to turbocharged engines has allowed the Mercedes engineers to repackage the straight six engine, with no need for a complex exhaust manifold to improve torque of a naturally-aspirated engine. That allows the engineers to stand the engine up straighter in the engine bay creating more space.

With Mercedes committed to adding particulate filters to both its diesel and petrol engines, the inline configuration allows for both the turbocharger and particulate filter to go on one side of the engine. According to Heil that provides a major advantage over a V6 engine which takes up more space in the engine bay with its angled cylinder banks.