Mercedes-Benz will pave the way for what it describes as a new vehicle category when it unveils the Vision Grand Sports Tourer – “a new take on the groundbreaking touring saloon concept” – at the North American International Auto Show in January.

Besides an innovative six-seater arrangement deploying three rows of two seats, permanent all-wheel drive, drive-by-wire transmission control and a nearly all-glass roof, the Vision sports a newly developed diesel hybrid powertrain that. develops 234 kW.

Until Ricardo and Valeo demonstrated an Astra-based diesel 'mild hybrid' to manufacturers last year - now to be followed in 2004-5 by a diesel hybrid Multispace prototype under development by Ricardo, PSA and British technology firm Qinetiq - hybrid powertrains have been restricted to Toyota's and Honda's petrol-electric cars.

The Mercedes Vision's powertrain mates a 250 hp V8 CDI diesel from the S-Class with a 50 kW electric motor. As a result, the vehicle sports 234 kW of total power and 860 Nm of torque. The Vision Grand Sports Tourer can sprint from 0-62 mph in 6.6 seconds.

The diesel hybrid system's fuel consumption is 30 mpg according to the US measurement method. With future engine generations, the drive concept of the Vision Grand Sports Tourer will offer the potential for 33 mpg. In the European driving cycle; the Vision Grand Sports Tourer with a hybrid drive uses about 20% less fuel than a comparable diesel-only model.

With electronic control of both power sources, the electric motor kicks in when starting off, parking, driving in stop-and-go traffic or crawling in heavy traffic when less power is required. Only when more engine power is required does the V8 CDI fire up. During regenerative braking, the electric motor produces current for recharging the drive battery.