Mercedes plugs-in the S-Class hybrid

(Credit: Mercedes-Benz)

Okay, so after a pair of supercar reveals on yesterday, let's take a step in a different direction and focus on something more environmentally friendly.

Hot on the heels of the S 400 Hybrid's European launch, Mercedes-Benz is set to trot our its new Vision S 500 Plug-in Hybrid at the 2009 Frankfurt auto show. (Wait, isn't BMW's new hybrid concept also called "Vision?" Oooh, scandalous!)

The Vision S 500's engine room is predictably similar to that of the S 400. Both vehicles use the same direct injected V-6 gasoline engine, both vehicles feature a electric ring motor sandwiched between the gasoline engine and the 7G-Tronic seven-speed automatic transmission. However, there are a few crucial differences.

Firstly, the S 500's 44 kW/60 horsepower electric motor is about three times more powerful than the S 400's 15 kW/20 horsepower unit. Additionally, the S 500's larger 10 kWh lithium ion battery pack is housed over the rear axle, instead of in the engine compartment.

A more robust electrical component allows the Vision S to go up to 18 miles on EV power.

(Credit: Mercedes-Benz)

Finally, the Vision S 500 Plug-in Hybrid is, as the name implies, a plug-in hybrid electric vehicle (PHEV), with its own onboard charger. Mercedes-Benz claims that a rapid charge cycle takes less than an hour with a 20 kW source. Recharging a completely discharged battery to full with a conventional household socket takes about 4.5 hours. Not too bad, we think.

Fully juiced, the Vision S can drive for up to 18 miles on silent electric power before the gasoline engine has to intervene. Mercedes is claiming a certified consumption of 73.5 US mpg (on the New European Driving Cycle), which pretty much blows the S 400 hybrid's 29 mpg out of the water.