Here’s How Mercedes Uses a 48-Volt System to Improve its Cars

Fuel economy is one obvious upside to a hybrid system, but smoother power delivery and a lower idle offer more advantages.

With emissions and fuel economy standards becoming more stringent around the world, automakers are looking for new, clever ways to get power out of their vehicles while ensuring that all of the standards are met. In a lengthy article, Motor Authority got the inside scoop behind Mercedes-Benz’s 48-volt system, which will appear on the automaker’s new 3.0-liter inline-six-cylinder engine.

The 48-volt system, as the outlet reports, will appear on the 2018 Mercedes-Benz S-Class. However, it won’t reach the U.S. anytime soon. While U.S. bound S-Class models will get the system eventually, the automaker will release another, unspecified car with the same system first. For everywhere else, the S450 and S500 have the 48-volt system before migrating to different engines.

The 48-volt system, which Motor Authority claims can be seen as a mild hybrid system, allows the engine to run without any belts. It features an electric air-conditioning compressor, an integrated starter-alternator (ISA) between the engine and gearbox, an electric water pump, an electric supercharger, and a regular ol’ turbo.

That sounds complicated and it is. However, as powertrain engineers told the outlet, the complex system offers many upsides. First, it helps six-cylinder engines deliver V8 levels of power more efficiently. While the S500 model has always fitted a V8 engine, the new inline-six with the 48-volt system delivers the same amount of power more efficiently. Motor Authority reports that the motor is 22 percent more efficient than the old twin-turbo 4.0-liter V8.

The second advantage comes from the lack of belts. That creates fewer parasitic losses for the engine. The 48-volt system generates enough power to run belt-driven systems on its own. That ensures that the engine doesn’t suffer from any parasitic losses, however little they may be.

The 48-volt system’s other advantages include a smoother start-stop system, a lower idle (as low as 520 rpm), and a gliding function. The gliding function, as Motor Authority claims, happens when the battery has enough juice and when the vehicle is traveling on a downhill grade. The engine, as the outlet reports, “will decouple from the powertrain and shut itself off.” After its finished gliding down the hill, the ISA brings the engine back up to the proper speed.

While seeing the S-Class make the switch back to an inline-six engine gives us a bitter-sweet feeling, Mercedes clearly knows what it’s doing. With all of the advantages that the 48-volt brings with it, we can’t wait to see what car it appears on when it lands on our side of the ocean.