The New York International Auto Show played host to the world premiere of the Mercedes Benz ML450 Hybrid this week – a vehicle with fuel consumption and emissions that are up to 60 per cent less than a conventional eight cylinder SUV.
The ML450 Hybrid uses two-mode hybrid technology derived from the Global Hybrid Co-operation which brought together research and development from Daimler AG, BMW, General Motors and Chrysler. The car has been specifically developed for the North American market.
Among its features, the ML450 Hybrid includes a system output of 250kW and a combined torque of 517Nm. Its city fuel consumption is 21mpg and highway consumption is 24mpg.
The vehicle uses a transmission unit with two compact electric motors, three planetary gear sets and four clutches. This allows power to be split into an electrical and mechanical path whereas conventional one-mode hybrid cars do not have mechanical ratios leaving the bulk of power to be transferred via the electrical path with higher electrical output meaning lower efficiency.
With increasing engine loads and higher speeds the two-mode hybrid shifts the power transfer from the electrical path to the mechanical drive. This makes it much more efficient in all situations whether in stop-and-go traffic or on fast motorways. The four clutches meanwhile distribute the driving force depending on the situation or the driver’s requirements. For example, when moving off or at a low speed the second gear operates in electric continuously variable transmission mode creating a smooth and comfortable drive; whereas in the first and third fixed gear the electric motors both work synchronously for additional energy for acceleration or to store during braking and coasting.
The vehicle will be available with a Sport mode that provides the handling of a conventional automatic transmission with very short shift times. The car will be produced at the Mercedes Benz plant in Tuscaloosa, Alabama.
