New engines and 48-volt systems are on the docket.

Mercedes-Benz is preparing to give the C-Class a mid-cycle update. The visual changes will be minor, as they always have been, but the modifications under the sheet metal will be much more significant.

In America, the C-Class line-up will start with a brand-new turbocharged 2.0-liter four-cylinder engine, according to sources who spoke to British magazine Autocar. In some applications, it will be part of a 48-volt electrical system that will provide a small power boost and help the C burn less gasoline.

The gasoline-electric C350e will carry on with a bigger electric motor programmed to provide more power. It will also boast faster charging hardware, and its lithium-ion battery pack will provide up to 31 miles of electric-only driving. That's on the wildly optimistic European testing cycle; the U.S.-spec model's figure will undoubtedly be much lower.

Interestingly, the mid-range C43 won't get Mercedes' new 3.0-liter straight-six engine. It will instead carry on with an evolution of the turbocharged 3.0-liter V6 engine that powers today's model. At the top end of the line-up, the C63 will get a tweaked version of AMG's ubiquitous twin-turbocharged 4.0-liter V8.

All engines will shift through a nine-speed automatic transmission. Rear-wheel drive will come standard, and Mercedes' 4Matic all-wheel drive system will be offered at an extra cost on select models.

Buyers in Europe will have access to several diesel-powered models, including a diesel-electric variant named C400d EQ Power. None of them will be sold in the United States, however.

Autocar's sources suggested the sedan and wagon variants of the 2019 Mercedes C-Class will make their debut in March at the Geneva Auto Show. The German firm will wait until the New York Show to unveil the coupe and convertible variants.

Note: Euro-spec 2015 Mercedes-Benz C300 BlueTec Hybrid pictured. Photos by Ronan Glon.