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Mercedes-Benz E 300 BlueTEC HYBRID

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The new Mercedes-Benz E 300 BlueTEC HYBRID returns 67.2 mpg along with 109 g/km CO
2
in Saloon form, and an Estate is also available.

This is a reduction in CO 2 emissions and fuel consumption of around 15 per cent compared with the E 250 CDI.

Mercedes claims that the 4-cylinder diesel engine of the E 300 BlueTEC HYBRID, with 204 hp and 500 Nm combined with an electric motor producing 250 Nm, makes it the most economical luxury-class vehicle in the world.

There’s also an E 400 HYBRID model with a V6 petrol engine producing 306 hp and 370 Nm, which is also supplemented by a further 250 Nm from the electric motor. The consumption figures based on the American CAFE standard are: City 24 mpg, Highway 31 mpg, Combined 27 mpg.

The new hybrid models are having their world premiere at the Detroit Motor Show (14 to 22 January 2012) and will appear on the market over the course of the year.

In addition to diesel and petrol variants there will also be right-hand drive hybrid variants.

The E 300 BlueTEC HYBRID is initially planned to be launched on the European market, while the E 400 HYBRID will be made available on the American market first, followed by other countries such as Japan and China later.

The new hybrid models from Mercedes-Benz are part of the company’s intelligent downsizing strategy which aims to make conventional models perform significantly more efficiently than ever before – without compromising when it comes to driveability or comfort.

Mercedes claims that the cars have been developed to deliver good economy in real-life driving.

Features of the hybrid system include:

Stationary vehicle/ECO start/stop function

Manoeuvring : parking or turning are for the most part carried out in electric mode

Accelerating : moving off and driving at low loads are carried out in purely electric mode. Accelerating from a standstill is powerful, since the full torque of up to 250 Nm is available from the electric motor

Boost function : the electric motor supports the combustion engine when accelerating, such as when executing an overtaking manoeuvre, by providing additional drive torque

Cruising : at constant speeds, the engine control unit shifts the operating range towards lower specific fuel consumption levels

“Sailing” : the “sailing” function can be used at speeds below 160 km/h. With this function, the combustion engine switches off and the desired speed is maintained primarily by using the electric motor, until the batteries need to be recharged

Recuperation of kinetic energy (regenerative braking) in deceleration mode or when braking: during deceleration the electric motor works as a generator and stores the converted kinetic energy back in the high-voltage battery.

The hybrid drive unit is an enhancement of the module used in the S 400 HYBRID and is based on the 7G-TRONIC PLUS automatic transmission.

A new element is the lack of hydraulic torque converter. Instead a wet clutch has been added, as also found in a number of AMG models. As a result, the electric motor can be integrated into the transmission unit in such a way that it only requires marginally more installation space than the 7G-TRONIC (+65 mm). The lack of converter allows for a purely electric driving mode as well as the “sailing” function, and also therefore significantly increases the potential for reducing consumption.

The compact electric motor, which is installed in the clutch housing between the engine and the transmission to save space, is a 3-phase AC internal rotor magneto motor, which develops a peak output of 20 kW and a peak torque of 250 Nm at an operating voltage of 120 Volts.

The electric energy of the hybrid drive comes courtesy of the high-voltage lithium-ion battery which has been specially developed for automotive use. Its characteristics include an output of 19 kW and an energy content of 0.8 kWh, enabling the E-Class to achieve a speed of up to 35 km/h and a range of up to one kilometre in purely electric mode.

Major advantages over conventional nickel/metal hydride batteries include a higher energy density and better electrical efficiency, together with more compact dimensions and a lower weight. Thanks to space-saving installation in the engine compartment, where it replaces the conventional starter battery, the interior space and boot capacity remain unchanged.

Read our review of the Mercedes-Benz E220 CDI Blue Efficiency