Last year, Mercedes-Benz announced that in addition to working with GM and BMW on the Two-Mode hybrid system, they would also collaborate with BMW on a less complex mild hybrid that could be adapted to most of their vehicles. The first product of that collaboration is being displayed this week at the Frankfurt Motor Show. A pair of S-Class sedans with the mild hybrid system are on display in S400 and S300 Bluetec guises.
The S400 hybrid uses the 3.5L gasoline V-6 and has a total combined output of 299 hp/ 375 Nm with the electric assist. As you might expect, the S300 Bluetec hybrid mates the 3.0L Bluetec diesel V-6 to the new mild hybrid set up to peaks out at 560 Nm of torque. The two luxury sedans reach 29.8 mpg and 43.6 mpg (both in US gallons) respectively. That latter number is particularly impressive considering the girth of the S-Class.
The hybrid system itself consists of an electric motor/generator/starter sandwiched between the flywheel and transmission. It can provide power boost, start/stop capability, and regenerative braking. Energy is stored in a small lithium-ion battery pack that is mounted under-hood. This would make the S-Class hybrids the first such production vehicles to use a lithium battery. The S400 is due on the market in 2009 with the S300 a year later.
2009: S 400 HYBRID sets a new note in the luxury segment
At the same time as the ML 450 HYBRID, Mercedes-Benz will be launching an S‑Class with petrol hybrid on the market. In the S 400 HYBRID, which will also be available from mid-2009 in Europe, the 205 kW/279 hp V6 petrol engine is combined with a hybrid module delivering from the outset 160 Nm and 15 kW/ 20 hp. The combined maximum power output is 220 kW/299 hp, the combined maximum torque amounts to 375 Newton metres.
The S 400 HYBRID can accelerate in 7.3 seconds from 0 to 100 km/h and reach an electronically limited top speed of 250 km/h. Yet even with such excellent performance, this superb combustion engine requires a mere 7.9 litres per 100 kilometres in the NEFZ cycle. This results in CO2 emissions of just 190 grams per kilometre, making the S 400 HYBRID the most fuel-efficient luxury petrol engine saloon in the world, independently of whether competitors pit a petrol- diesel- or hybrid drive against it. Only the S 300 BLUETEC HYBRID, the S 400 BLUETEC HYBRID and the F 700, also presented at the IAA by Mercedes-Benz, can improve significantly on the world record set by the S 400 HYBRID in terms of low fuel consumption and CO2 emissions.
Enjoyable and economical driving from one efficient unit
The compact hybrid module installed in all the S-Class hybrids comprises a disk-shaped electric engine, which also functions as a starter motor and dynamo. This system offers a double benefit, working on the one hand in various ways to save fuel, and making driving so much more fun.
The main reason for the increased driving enjoyment is what is known as the boost effect, whereby the electric engine supports the combustion engine during the high-consumption acceleration phase with a maximum extra torque of 160 Newton metres. With this high torque the electric engine assists the combustion engine heartily when accelerating from very low engine speeds. As a result, the combustion engine itself needs less time and energy to build up its maximum torque. The only thing the driver notices from this synergy of the two power units is a supremely effortless power output whenever he starts off.
The hybrid module also features a comfortable start-stop function which switches the engine off whenever the vehicle stops, for example at traffic lights. Once the vehicle is ready to move off again, the electric engine starts the main engine again so gently, that it remains virtually unnoticed. This of course also contributes to fuel savings and is kind to the environment: since the engine starts virtually immediately, virtually no unburned fuel is discharged when starting off. When decelerating, on the other hand, the electric engine functions as a generator, and can recover braking energy in what is known as the recuperation process. This energy is stored in a powerful but compact lithium-ion battery pack in the engine compartment, ready for use when required. The engine management of this complex system is governed by a powerful control unit, which is also installed close to the engine.
2010: S 300 BLUETEC HYBRID with 560 Nm and just 5.4 l/100 km
The tremendous savings potential of the modular technology concept being applied by Mercedes-Benz is underlined by the S 300 BLUETEC HYBRID, due to arrive on the market in 2010, too. The configuration and performance data of this engine are identical to those in the E 300 BLUETEC HYBRID. In the S-Class too, the BLUETEC/Hybrid combination develops a maximum torque of 560 Newton metres, comparable with that of a large-volume V8 petrol engine. When combined with the standard 7G-TRONIC seven-speed automatic transmission, the S 300 BLUETEC HYBRID accelerates from 0 to 100 km/h in just 8.4 seconds, and it can reach a top speed of 240 km/h. Even with this superior performance, fuel consumption stands at just 5.4 litres of diesel per 100 kilometres, corresponding to a mere 142 grams of CO2 per kilometre ‑ 57 grams, or some 30 per cent, less than the current best saloon in the S-Class segment anywhere in the world.
The S-Class uses the version of BLUETEC with AdBlue injection system. Thanks to the combination of BLUETEC and hybrid technology - the only combination of this nature in the world, delivering the most economical and environmentally compatible premium cars in the world - the S 300 BLUETEC HYBRID has the potential to meet the most stringent emissions standards applicable anywhere in the world – for example, the European EU6 standard or the US 50-state BIN5 standard.