Germany: Mercedes-Benz's first hybrid has world's first lithium-ion automotive battery
By: Glenn Brooks, Thursday, September 18, 2008, AutomotiveWorld.com
The new Mercedes-Benz S 400 BlueHybrid, a mild hybrid, is a new version of the three-year old S-Class sedan. Its 279hp (208kW) 3,498cc V6 gasoline engine is based upon the unit in the existing S 350, but an electric motor/generator and the first lithium-ion battery in a production car have been added.
The S 400 BlueHybrid was previewed by the S 400 hybrid, a prototype that was exhibited at the Frankfurt IAA a year ago.
The new car's electric motor kicks in with extra 88 lb ft of torque under hard acceleration, as well as an additional 20 horsepower. Mercedes-Benz claims the combined torque output is 285 lb ft.
Unlike the Lexus GS 450h, which has just been updated with a larger boot thanks to a less intrusive battery pack behind its rear seat, the S 400 BlueHybrid has its battery under the bonnet. The car's bootspace is therefore identical to that of other standard wheelbase S-Class sedans.
Like the Lexus, there is also a gauge to show the driver where the energy is flowing.
As the Mercedes is a mild hybrid, unlike the Lexus, it cannot run on its batteries alone at low speeds.
The new car has start-stop and regenerative braking. As for concerns about power steering and climate control whilst the engine is stopped, there need be none, as the new variant, like other S-Class sedans, does not have a belt driven pump and compressor respectively - both are electrically-powered.
The issue of safety of the new battery (its power also means the conventional battery has been done away with) has been dealt with in several ways. For example, it is mounted in a high-strength steel housing. Bedding the cells in a special gel effectively dampens any jolts and knocks, Mercedes-Benz claims. There is a blow-off vent with a rupture disc and a separate cooling circuit, while an internal electronic controller continuously monitors the safety requirements and immediately signals any malfunctions.
Further, there is separation of the battery terminals, individual safety-wiring for all high-voltage components and continuous monitoring by multiple interlock switches. This means that all high-voltage components are connected by an electric loop, the OEM adds. In the event of a malfunction, the high-voltage system is automatically switched off.
Mercedes-Benz claims the S 400 BlueHybrid returns average fuel consumption of 7.9 litres/100km, with a CO2 number of 190g/km. These figures, it states, make the car not only the world's most economical luxury sedan powered by a spark-ignition engine but give it the lowest emissions for a car in this vehicle and performance class.
Sales of the forthcoming S 400 BlueHybrid in European markets are due to start in the summer. No right-hand drive cars are planned. As of now, it has no direct rivals - the similarly-sized Lexus LS 600h and long wheelbase LS 600hL are powered by a 5.0-litre V8. Sources claim BMW will soon announce an 'ActiveHybrid' version of its new 7 Series as a rival for the S-Class, however.
Mercedes-Benz itself will follow up the S 400 BlueHybrid with a diesel-electric version of the S-Class "after 2010", having shown such a model as a prototype, the S 400 Bluetec hybrid, at the Frankfurt IAA in September 2007. A version with a four-cylinder diesel engine, the S 300 Bluetec hybrid, was another prototype that appeared at the Frankfurt show. No production plans were announced, nor has there been any news on this vehicle since.
As for gasoline-electric prototypes, the ML 450 hybrid also appeared in concept form at the 2007 IAA, with production due to start in 2009, the firm announced at the time. As 'Bluetec' is the sub-branding for all Mercedes-Benz diesels and 'BlueHybrid' now the production badging for gasoline-electric hybrids, this SUV is therefore expected to be named 'ML 450 BlueHybrid'. At this stage, it is not known how Mercedes-Benz will refer to any future diesel-electric hybrid cars.
Published on Thursday, September 18, 2008
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