Mercedes-Benz DIRECT HYBRID and BLUETEC HYBRID

Press Release

In Short

 

Vision of the Future in 2005

 

• Petrol cars - as efficient as diesels
• Diesel cars - as clean as petrol cars

At the International Motor Show (IAA) 2005 in Frankfurt, Mercedes-Benz will be unveiling the "DIRECT HYBRID" and the "BLUETEC HYBRID," two groundbreaking concept cars. Using the new S-Class as an example, the company is exhibiting unique designs for yet again markedly improving fuel consumption and emissions in the near future � while preserving high dynamic ride comfort. The focus is on combining optimised petrol and diesel engines with a hybrid system and with ultra-modern exhaust gas purification.

The paramount goals for Mercedes-Benz in vehicle development are maximum ride comfort, dynamics and safety combined with economical consumption and environmentally-compatible emission levels. "For the drive concepts of the near future the objective is to make petrol cars as efficient as diesels, and diesels as clean as petrol cars" stated Dr. Thomas Weber, Member of the Board of Management of DaimlerChrysler AG responsible for research and technology and for development at the Mercedes Car Group.

For the petrol engine car, the main emphasis is on reducing fuel consumption even further. With the second-generation spray-guided petrol direct injection system, the engineers at Mercedes-Benz have achieved a crucial innovation that allows considerable fuel savings. Using the current 3.5-litre V6 as the basis, this technology was implemented under the bonnet of the new S-Class. This vehicle, which incorporates a compact, high-torque electric motor, will be presented in Frankfurt as the "DIRECT HYBRID."

Now that the particulate filter has been introduced as standard equipment, the task for the diesel is to adhere to the most stringent exhaust limits worldwide with regard to nitrogen oxide emissions, too - while retaining the celebrated fuel economy. Nitrogen oxides are currently the only exhaust gas component still emitted in greater quantities by the diesel than by the petrol engine. The goal of achieving the lowest possible emissions has been implemented commendably by the "BLUETEC HYBRID" concept car based on the new 3-litre V6 diesel in the new S-Class � and also incorporating a high-torque electric motor. The crucial element in the success of this system is "BLUETEC," a new exhaust gas purification technology that reduces the nitrogen oxides by about 80 per cent through selective catalytic reduction (SCR). This technology makes the "BLUETEC HYBRID" the cleanest diesel in the world.

Both of the drive systems in the concept cars introduced in Frankfurt are combined with an electric motor integrated in the drive train, thereby becoming what are called "mild hybrids". This makes it possible to once more significantly reduce the already excellent fuel consumption of the optimised combustion engine, especially in urban stop-and-go traffic. The combustion engine switches off whenever it is not needed. At other times, the combination of combustion engine and high-torque electric motor act in concert to ensure a powerful and silky-smooth start when pulling away. Moreover, the electric motor reclaims energy during coasting and braking. These combined features allow a 20 per cent reduction in fuel consumption in the "BLUETEC HYBRID" relative to the comparable predecessor model, and as much as a 25 per cent reduction in the "DIRECT HYBRID."

The two drive systems not only provide a dynamic driving performance, but also are extremely fuel-efficient and comply with the most stringent emissions standards worldwide. The drive system of the vision S320 BLUETEC HYBRID have a combined output of 179 kW/243 hp and 575 Nm of combined torque. The car can accelerate from zero to 100 km/h in 7.2 seconds and its top speed is electronically limited to 250 km/h. The vehicle is extremely fuel efficient, consuming only 7.7 litres of fuel per 100 km in the NEDC. The corresponding values for the S 350 DIRECT HYBRID are: 221 kW/300 hp; 395 Nm, 7.5 seconds, 250 km/h and 8.3 litres/100 km.

In the coming years, the hybrid - either in its mild or full hybrid configuration - can supplement the combustion engine in certain regions and traffic situations where it represents a reasonable and economical option for increasing dynamics, comfort and fuel efficiency. Trend-setting examples of such hybrids are the "DIRECT HYBRID" and "BLUETEC HYBRID" concept cars introduced at the IAA.

On 22 August 2005, DaimlerChrysler and General Motors (GM) signed a cooperation agreement regarding the joint development of hybrid drive systems begun in late 2004. In a memorandum of understanding, another partner, BMW, has now declared its intention to conclude an agreement with GM and DaimlerChrysler towards the end of the year. The three global automakers are cooperating in order to pool their expertise for the rapid and efficient development of future hybrid drive systems.

Mercedes-Benz is combining its clear commitment to the combustion engine as the indispensable basis for the coming years with a strong effort to help establish clean fuels and fuel alternatives. Their use goes a long way towards reducing emissions, because they immediately make all vehicles in the market cleaner and not only new cars. Synthetically produced designer fuels from natural gas or biomass are one option here. In particular, the fuels produced from biomass can contribute towards reducing CO2 emissions. In the ideal case, the CO2 produced by the combustion of biogenic fuels was previously absorbed by the plants during their growth, resulting in a closed CO2 cycle. Mercedes-Benz is actively participating in making SunDiesel a viable product for the market.

Yet the fuel cell remains the vision of researchers and developers at Mercedes-Benz for the automotive drive of the future. They have been working on it for more than ten years. The company has more than 100 fuel cell vehicles, from passenger cars to buses, engaged in road trials throughout the world � the largest fleet of its kind. To date, the A-Class F-Cell fleet has covered a total of around 440,000 kilometres in around 90,000 hours of operation. The reactions of the customers and passengers are very positive and give valuable insights that will help ensure the success of further development work.

Full Story

• Mercedes-Benz Advanced Power
• Pioneering drive concepts: Environmentally friendly, economical and dynamic

Mercedes-Benz is presenting two unique drive concepts at the International Motor Show 2005 in Frankfurt. In two concept cars � “DIRECT HYBRID� and “BLUETEC HYBRID� � each based on the new S-Class, the most efficient and environmentally friendly designs from the world of petrol and diesel engines are combined with a hybrid. While offering the maximum environmental compatibility, these vehicles simultaneously guarantee good driving dynamics and ride comfort.

At the start of the 21st century, it is becoming clear that, despite the merit of the fuel cell as a long-term prospect, the internal combustion engine will continue to play a major role over the medium term. It will therefore remain a central focus for the efforts of the Mercedes engineers in the coming years � in both its petrol and diesel forms. In both cases, the objective is to make still further improvements in fuel consumption and environmental compatibility. As a manufacturer of high-quality cars, Mercedes-Benz is shouldering its social responsibility in this respect. Moreover, the company sees a special obligation in the fact that it is a technological leader.

The petrol engine is becoming more economical

In the case of the petrol engine car, the main emphasis of development is on further reducing fuel consumption. Its advantages � high performance and outstanding ride comfort at low costs � will naturally be preserved. Since 2003, petrol engines have been meeting the emissions standards now in effect in Europe and the USA, since this year including the SULEV (Supra Ultra Low Emission Vehicles) standard, and Mercedes-Benz is also well-equipped to deal with forthcoming, more stringent exhaust emissions limits.

Compared with the diesel, the petrol engine still harbours considerable potential for reductions in consumption. With the second generation of the spray-guided petrol direct injection system, the engineers at Mercedes-Benz have achieved a crucial innovation that allows considerable improvements in fuel consumption. Using the current 3.5-litre, 4-valve V6 with fully variable valve timing as the basis, this technology was implemented in the Vision S350 “DIRECT HYBRID.�

Compared with the first-generation direct injection designs, the latest combustion process from Mercedes-Benz offers a significant improvement in fuel consumption and engine performance merely by ensuring the formation of a stable fuel spray through the injection nozzle. For the spray-guided combustion process, engineers developed a special piezo injection valve and a fuel system with a high pressure of 200 bar. The stability of the injection spray � one of the critical aspects of the process � is ensured by a special injection nozzle that opens to the outside and is activated at ultra-high speeds by a piezo crystal. The quantum leap of this innovative process lies in the control of the fuel spray and the extremely rapid timing of the piezo nozzle, which allow the formation of a fuel-air mixture with the ideal flammability. The thermodynamic efficiency improves markedly and enables low fuel consumption with better engine performance. With the innovative direct injection process, the 3.5-litre V6 in the “DIRECT HYBRID� generates an output of 215 kW (292 hp) at 6,000 rpm. Its maximum torque of 365 Nm is already accessible at 2,400 rpm and remains available over a broad range of engine speeds up to 5,000 rpm.

The exhaust treatment for this layered direct injection process takes place in the double-stream exhaust system. A NOx trap system for reducing the nitrogen oxides is also used, in addition to the two bulkhead catalytic converters and controlled recirculation of exhaust gas in each branch. It is thus possible to achieve extremely low exhaust emissions levels, which naturally satisfy the current EU 4 exhaust emissions standards and the forthcoming EURO 5 limit.

The design is rounded out by another technological feature that helps reduce consumption and also contributes to driving enjoyment � the built-in high-torque electric motor.

The built-in electric motor - a boost for the environment, fuel efficiency and comfort

This particular solution is what makes the two concept cars “mild hybrids�. To save space, the electric motor is installed between the engine and the 7G-TRONIC automatic transmission’s converter. Depending on the driving situation, it functions as a starter or a generator. This is particularly advantageous in the heavy traffic of an urban area, because it makes it easy to create an automatic stop-and-go transmission that alone can save three to six per cent of fuel under these circumstances. A quick touch of the accelerator and the electric motor smoothly brings the engine back to life. At the same time, the electric motor supplies a maximum of 250 Nm to the drive power during starting. It thus provides optimal support for the combustion engine which � as a consequence of its operating principle � first builds up its torque as the revs increase. The combination of motor and engine boosts the maximum available torque to 395 Nm and makes the vehicle’s starting characteristics powerful.

The electric motor concept unfolds its greatest potential in heavy stop-and-go traffic. Despite its dynamic acceleration (0 – 100 km/h in 7.5 seconds) the “DIRECT HYBRID� uses just 8.3 litres of petrol per 100 km in the European Driving Cycle. The advantages of this impressive technology package add up to an impressive result: Compared with its predecessor model, the S 350 V6 (W 220), the power has been increased by 19 per cent and the consumption cut by an impressive 25 per cent.

By reversing its function, the electric motor can also regain a portion of the vehicle’s kinetic energy during phases of coasting without acceleration and when engaged in regenerative braking. This energy is stored in a new type of rechargeable high-performance battery using lithium ions. Energy storage devices of this type are distinguished by their high power density, and can charge and discharge electrical energy extremely rapidly. At the same time, Mercedes-Benz is also investigating the use of high-performance capacitors known as ultracaps. Both of these energy storage devices can contribute a few percentage points towards fuel savings, depending on the application profile.

Diesel with “BLUETEC� and hybrid unites driving pleasure, economy and ecology

The latest concept car, the “BLUETEC HYBRID,� also presented by Mercedes-Benz in an S-Class at the IAA, even goes a step further. This vehicle unites a maximum of emissions reduction technology with the diesel’s typical advantages of economy and agility and the consumption technology of a mild hybrid. Like the “DIRECT HYBRID� petrol variant, the “BLUETEC HYBRID� uses an additional 6 kW/8.2 hp electric motor, which serves both as starter and as starting booster. It can also be used for regenerating power from kinetic energy. The basic drive of the “BLUETEC HYBRID� is the 3 litre V6 diesel engine, a variant of the 320 CDI with 173 kW/235 hp of output and a maximum torque of 540 Nm that is already available at between 1,600 and 2,400 rpm. “BLUETEC� offers a technology with which the diesel can also meet future emissions values in Europe, the USA and Japan. This technology package can achieve consumption figures of 7.7 litres /100 km in the European Driving Cycle. Compared to the S-Class predecessor model (S 400 CDI/W220) which was itself unusually economical, this represents a further saving of 20 per cent for comparable power and torque. Driving pleasure, economy and ecology are the distinguishing features of this concept car and will not cause contradictions at Mercedes.

“BLUETEC� � the world’s cleanest diesel

Thanks to its future-oriented research and development with “BLUETEC� technology (selective catalytic reduction, SCR), Mercedes-Benz is excellently equipped to meet future emissions requirements in Europe, Asia and the USA. “BLUETEC� has already been fitted to more than 5,000 Mercedes-Benz commercial vehicles such as the Actros und the Axor in customer’s fleets. “BLUETEC� has reduced their emissions of nitrogen oxides by around 80 per cent. This means that these vehicles already fulfil the EURO 5 exhaust gas standards, which will first become binding in 2009 for trucks. The precondition for this is the targeted and measured addition of “AdBlue� � an aqueous carbamide solution � into the exhaust line. This reacts with the nitrogen oxides in the catalytic converter to form ammonia (NH3) as an intermediate product which then is converted into the harmless natural products of water and nitrogen. In Europe, the supply network for “AdBlue� already includes 400 filling stations. Mercedes-Benz now intends to utilize the vast potential of this technology for diesel passenger cars too, and is currently carrying out tests on such vehicles worldwide. “BLUETEC� is available now and is currently the best technology for reducing emissions of nitrogen oxides � it can even be used to meet the planned stricter emissions guidelines in California.

The AdBlue must be metered precisely according to the driving situation in order to always achieve the maximum catalytic converter conversion rates. The customer, however, doesn’t need to worry about that. In order to guarantee keeping within the NOx exhaust emissions limits over the normal service interval, a 22-litre tank has been built into the spare-wheel well of the S Class. Average AdBlue consumption is around 0.1 litre per 100 kilometres. Should the supply run out before the next service, a signal in the instrument cluster warns the driver to visit a service station in plenty of time. This tank is therefore sufficient for the driving distance between two service intervals and the service personnel simply fill the tank up automatically when the car goes in for its next service.

Mercedes-Benz has set itself the objective of building the world’s cleanest diesel, and christened it “BLUETEC.� Diesels should be as clean as petrol engines as far as emissions are concerned, and thus ready for future emissions regulations worldwide. The company is following a three-stage plan to accomplish this:

• Internal measures to make the combustion process as efficient and clean as possible.
• Oxidation catalytic converters lower the carbon monoxide and hydrocarbon emissions and particulate filters cut the particulate emissions to a barely measurable level.
• “BLUETECâ€ÂÂÂ� technology will reduce emissions of nitrogen oxides â€â€ÂÂ� the last remaining exhaust gas constituent that is still present in higher levels than in petrol engine exhausts â€â€ÂÂ� by 80 per cent.

This can fulfil even the strictest exhaust emission limits currently under discussion and so secure the future of the diesel drive in markets such as the USA and Japan.

Comprehensive diesel expertise at Mercedes-Benz

Rudolf Diesel’s principle of self-ignition is closely linked with the history of Mercedes-Benz. The brand has acquired more than 70 years’ experience with the diesel engine worldwide. Milestones such as the world’s first production diesel passenger car (1936), the delivery of the one-millionth diesel passenger car in the post-war era (1971), the first use of a diesel particulate filter in the USA (1985) and premieres of the four-valve technology (1993) and the diesel direct injection passenger car (1996) are just a few of the highlights in the diesel engine’s success story. Since the presentation of the top-of-the-range model S400 CDI in 2000, Mercedes-Benz has offered the widest range of diesel engines in Europe � from the powerful V8 to the economical three-cylinder engine for the smart. And in autumn 2003, Mercedes-Benz became the world’s first automotive brand to offer diesel engines complying with the EU4 emissions standard in combination with diesel particulate filters. Today, Mercedes-Benz offers all 42 diesel passenger car models with a maintenance-free diesel particulate filter as standard equipment � thereby setting a unique standard.

The diesel’s popularity is due to the unmatched efficiency of its combustion process. The developments of the last 15 years � for example, the electronic valve timing, four valve technology, common-rail-direct injection and turbochargers with variable geometry � have enabled the Mercedes developers to build on its good consumption characteristics, and so to extend its lead over the spark ignition engine. What’s more, thanks to the engine’s excellent torque characteristics, these have been joined by convincing driving pleasure and comfort � properties that put the diesel on a level with the petrol engine, and sometimes even a cut above.

Fifty-seven per cent of all Mercedes customers in Western Europe alone decide to purchase a fuel-efficient diesel car. In the USA, diesel passenger cars have fallen back after their great successes in the 1980s. However, there are now positive signs of a change in the perception of this drive system, which has undergone enormous development both economically and technologically. The factors behind this change are the currently extremely high crude oil prices and the concern over national security of supply. Thanks to this political background and the US traffic conditions, with vast overland stretches ideally suited to the diesel, the engine continues to hold great potential in the USA.

Three E 320 CDI production vehicles impressively demonstrated that the V6-CDI is not just a proverbially economical and reliable engine at record drives in Laredo, Texas, last spring. They also showed their stamina and their sportiness by setting a number of world records at an average speed of 224.823 km/h over 100,000 miles.

The vehicles participating in the world record drives were also equipped with the current state of the art in exhaust purification technology. Thanks to the use of a maintenance-free diesel particulate filter, the particulate emissions typical of diesels were cut by more than 90 per cent � better than the EU 4 exhaust gas limits require. And once the tough and unusual stresses of the record drive were over, the TÜV (Technical Inspectorate) was able to confirm that the strict legal limits were still being maintained.

Fuel still holds great potential

Every efficient and environmentally friendly drive concept is a partnership of two elements � the engine itself and the fuel. Only when the fuel is burnt as completely as possible, with the minimum of residues, can the drive system operate with the lowest emissions. That means that every fuel � for petrol and diesel engines � should be matched to the respective combustion concept.

Sulphur, a natural component of petroleum, is a decisive player in this context, as it has a substantial effect on the emissions. On the one hand, sulphur and its products, the sulphates, have a negative effect on the particulate emissions. On the other, sulphur damages NOx traps. That’s why Mercedes-Benz is backing BLUETEC � which is more tolerant of sulphur � for reducing oxides of nitrogen in diesel exhausts. Nonetheless, the worldwide use of fuels with a maximum sulphur content of 10 ppm � that corresponds to a concentration of ten parts of sulphur to one million parts of fuel � is to be desired.

This low sulphur concentration is already standard in large parts of Western Europe. However, this is still a long way from being the case in other parts of the world. In the USA, for example, diesel grades with sulphur contents of 350 ppm and more are still normal. Plans, however, call for sulphur levels to be cut to 15 ppm in the USA by 2006. Mercedes-Benz is therefore actively supporting the introduction of cleaner fuels as a part of its efforts to offer customers vehicles with the most modern technology possible and so with the lowest possible emissions. Consumption and emissions can only be further optimised by means of the combination with optimised fuels � for diesel and petrol engines. And what’s more, this step would immediately have a significant positive effect on the pollutant emissions of older engines too � over the entire vehicle fleet. Mercedes-Benz therefore views efforts to reduce the sulphur content of fuels worldwide as an urgently needed improvement in fuel quality, although it is not the only improvement necessary.

The natural gas alternative: Good for the environment and the wallet

A logical option for an environmentally friendly drive system, in that it’s already available, is a switch to natural gas. Mercedes customers have had this option since the spring of 2004, with the E 200 NGT (Natural Gas Technology). The E 200 NGT, the top-performing natural gas-powered saloon on the market, can run on either natural gas or unleaded premium petrol. Switching between the two drives is also possible while the car is being driven, and the transition isn’t even noticed by the driver. The engine is based on the E 200 Kompressor, and it is tuned so that power (120kW/163 hp) and maximum torque (240 Nm) are the same with either fuel. The fact that the 18 kilograms of natural gas are transported in a gas cylinder, in addition to the petrol tank, results in the vehicle having a range in excess of 1,000 kilometres.

The natural gas drive has economic and environmental benefits. Depending on its origin, natural gas consists of far more than 90 per cent methane (CH4). Methane’s purity and high hydrogen content mean that its combustion produces less pollutants than burning conventional liquid fuels. And as a result of its low carbon content, the CO2 emissions are 20 per cent lower. And the operating costs are lower by half, a very welcome added benefit for the customer. Based on the current price of natural gas, about 0.72 euros per kilogram, that corresponds to a per-litre price of 0.48 euros, when calculated as the energy equivalent of petrol. This shows that natural gas is not only an environmentally friendly alternative but also an economical choice: With the definition of the minimum tax rates valid until the year 2020, customers can enjoy the security of long-term planning.

Gas To Liquid: Fuel from natural gas

Another viable transition to a fuel of the future could be a liquid fuel synthesized from natural gas, which otherwise wouldn’t be economical to use. This conversion produces what’s known as a “gas-to-liquid� (GTL) fuel. This indirect application of natural gas after it has been liquefied would have a decisive advantage: A dedicated network of filling stations would not be necessary. In contrast to the direct use of natural gas, which must be stored in pressurised tanks, GTL can be handled at the filling station like conventional diesel fuel and offers further benefits in terms of emissions. It has already been demonstrated that it will be possible to economically produce such a fuel in the future. In view of rising crude oil prices, this represents an economically feasible and environmentally friendly alternative. Such “designer fuels� are free from sulphur and aromatics and can, within certain limits, be “customised� for future combustion processes.

Thinking a step ahead: Fuel from biomass

In terms of CO2 emissions, fuels made from biomass offer even better perspectives. An ideal scenario for the use of these fuels is that the CO2 emitted during combustion was absorbed by the plants during their growth, giving rise to a closed cycle. For the last five years, Mercedes-Benz has been strongly committed to the development and introduction of such synthetic fuels made from biomass � known as SunDiesel or BTL (biomass-to-liquid) fuels.

The production process for SunDiesel � which is supported by DaimlerChrysler � begins with a multi-stage process developed by Choren in Freiberg, Germany. Choren derives the biogenic diesel fuel from wood scraps and clippings collected during forestry operations. The first step is to carbonise the wood waste. This in turn produces bio-coke and carbonisation gas � preliminary stages of a synthesis gas from which SunDiesel is made, using the well-known Fischer-Tropsch synthesis process. The decisive advantage of this process is that almost any type of biomass can be used � even residual materials like straw or waste cuttings from agricultural fields. That’s the difference between SunDiesel and conventional biodiesel (also called plant methyl ester), which uses only plant fruits that contain oil.

With the pilot plant currently in operation, production still costs about twice as much as producing diesel fuel from petroleum. But thanks to a European Union tax exemption, it is possible to achieve competitive production on a large-scale industrial basis. The objective announced by the EU is to gradually increase the share of biogenic fuels from the current level of about one per cent to eight per cent by the year 2020. That would mean Europe could reduce CO2 emissions by as much as 80 million tonnes. The environmental “balance sheet� shows that as much as 90 per cent of CO2 emissions along the entire BTL value chain, including transport and processing, can be avoided.

But SunDiesel is not only a very positive development in terms of CO2 emissions. Testing of Mercedes diesel engines shows that switching to synthetic fuels (GTL, BTL) alone would reduce particulate emissions by as much as 30 per cent and cut emissions of carbon monoxide and hydrocarbons by even as much as 90 per cent.

In addition to strongly supporting efforts by the German government and the EU to increase the use of renewable fuels, Mercedes-Benz intends to fill the tanks of all new diesel vehicles leaving its production plants with SunDiesel, as soon as there is a sufficient supply of the fuel.

The hybrid: Perspectives for special areas of application

Recent years have seen the introduction of hybrid technology, especially in Japan and the USA. The overarching objective behind this technology is to reduce fuel consumption. The technology is particularly effective at saving fuel in urban traffic, which is primarily characterised by frequent stops and low speeds. In the case of the combustion engine, the high-consumption operating points can be delegated to the second drive � the electric motor, which generates its maximum torque from a standing start. Intelligently controlled, the advantages of both drives can thus complement one another. Even greater savings can be achieved by the use of a stop-and-go automatic and the partial recovery of braking energy. It therefore makes sense to use this hybrid technology in heavy city traffic, thus improving both efficiency and comfort.

Mercedes-Benz has been working intensively on the implementation of various hybrid concepts since 1982. The company has so far produced several concept cars in different sizes and versions. The F 500 Mind caused a stir in 2003 as the first-ever research car to combine a diesel engine with an electric motor. As the precursor to the new R-Class, Mercedes-Benz also presented the Grand Sports Tourer as a hybrid version at the last Detroit Motor Show. This car combines a V8 diesel engine with 184 kW and a 50 kW electric motor. This parallel hybrid concept demonstrated savings potential of up to 20 per cent in the European Driving Cycle. And that’s with acceleration values (0 - 100 km/h in 6.6 seconds) that leave no shortage of driving pleasure.

Innovative: The two-mode hybrid drive

During the development of the latest generation of hybrid drives, the focus will be on the combination of a high-performance and compact drive. This involves a split-hybrid concept � an intelligent synthesis of series and parallel hybrid. In contrast to the familiar single-mode systems, the two-mode hybrid features a combination of two smaller electric motors with an automatic transmission. This patented solution can be accommodated in the vehicle in a space-saving arrangement. Because of its two-mode operation, the system also offers the advantage of reduced fuel consumption at the highest possible performance levels, particularly in the long-distance driving cycle. It also displays superior traction performance.

DaimlerChrysler has joined forces with General Motors (GM) for the development of this two-mode hybrid. A few days ago, BMW joined this cooperation under a Memorandum of Understanding. On the basis of the comprehensive experience of these three global automakers, the research and development activities will be coordinated in order to implement a modular concept with a combination of large-volume combustion engines and small electric motors that, insofar as possible, does not take up any additional space. Another joint aim is to make the hybrid particularly appealing to customers, not only in terms of its technology but also its costs. As part of this cooperation, Mercedes-Benz will concentrate on the development of luxury-class cars with rear-wheel and all-wheel drive.

Long-term goal � the fuel cell drive

Mercedes-Benz has been working on fuel cell technology since the early 1990s. As early as 1994, the company kick-started the development of the fuel cell drive with the first research vehicle, the NECAR 1. In this system, a chemical reaction between oxygen and pure hydrogen generates electrical energy, which then drives an electric motor. Mercedes-Benz thus opened up a far-sighted prospect for the 21st century � one that includes the vision of a zero-emission drive and the option of mobility without reliance on crude oil. Furthermore, the fuel cell drive is almost twice as efficient as conventional combustion engines, making it an environmentally-friendly alternative. Provided that the hydrogen is produced from renewable sources such as wind, water and solar energy, emissions of the greenhouse gas CO2 can be virtually avoided altogether.

Since the presentation of the first fuel cell vehicle in 1994 � the NECAR 1, in which the fuel cell drive took up the entire cargo space of a Mercedes van � the company has played a pioneering role in the development of this technology. For example, its performance has been significantly improved and the amount of space it requires has also been reduced to a minimum. Since the NECAR 1, a total of 20 prototypes and concept vehicles have been built, ranging from compact passenger cars based on the A-Class to the Mercedes Sprinter and Mercedes-Benz Citaro regular-service buses. Since 2003, the world’s first small-batch series of passenger cars � the “F-Cell� based on the Mercedes-Benz A-Class � has proven its suitability in everyday use when driven by customers. Together with 36 buses and a number of vans, the company currently has the largest fleet of fuel-cell powered vehicles in everyday use. A total of 60 Mercedes-Benz A-Class F-Cell vehicles are currently undergoing practical testing in Germany, Japan, the USA and Singapore. To date, the A-Class F-Cell has covered a total of around 440,000 kilometres in around 90,000 hours of operation, while the buses have driven 945,000 kilometres in 67,000 operating hours. This valuable practical experience will drive forward the successful continued development of this technology.

One of the most important breakthroughs was when the DaimlerChrysler researchers produced a fuel cell drive with cold-start capability. Improved structures in the fuel cell stack and new materials now ensure that the drive also starts in the winter months at temperatures of –20° C.

The next generation of fuel cell vehicles is the B-Class “F-Cell�. Here, the fuel cell drive will be significantly improved in terms of its performance. The high-torque 100 kW fuel cell drive outpaces the predecessor generation by 35 kW and combines zero-emission driving with dynamic performance. Furthermore, the range will be extended to 400 kilometres and the reliability and durability of the components will be improved.

The question as to how quickly the transition to the fuel cell age can be completed depends not only on the vehicle technology, but also largely on the creation of a universal infrastructure for the fuel. Mercedes-Benz is therefore actively working towards the introduction of the necessary social and political conditions.

Technical details:

S350 DIRECT HYBRID and S320 BLUETEC HYBRID

 

ÂÂÂÂ	S350 DIRECT HYBRID	S320 BLUETEC HYBRID
Engine	V6 petrol engine, spray-guided direct injection (2nd generation)	V6 CDI diesel engine with common-rail-direct injection
Engine designation	M272 DE35	OM642 DE30LA
Displacement in cm³	3498	2987
Transmission	7G-TRONIC automatic	7G-TRONIC automatic
Output of combustion engine kW/hp, rpm	215 kW/292 hp, 6000 rpm	173 kW/235 hp, 3800 rpm
Output of electric motor kW/hp	6 kW/8.2 hp	6 kW/8.2 hp
Combined output kW/hp	221 kW/300 hp	179 kW/243 hp
Torque Nm, rpm	350 Nm at 2400–5000 rpm	540 Nm at 1600–2400 rpm
Torque of electric motor Nm, rpm	250 Nm upon ignition/ 50 Nm at 1000 rpm	250 Nm upon ignition/ 50 Nm at 1000 rpm
Combined torque	395 Nm	575 Nm
Energy storage	Lithium-Ion battery	Lithium-Ion battery
Regeneration	8 kW max	8 kW max
Exhaust gas treatment systems	Computer-controlled 3-way catalytic converter, DeNox catalytic converter	Oxidation catalytic converter, DPF, BLUETEC (SCR system)
Fuel consumption in the NEDC in l/100 km	8,3	7,7
Change to the comparable pred- ecessor model in %	-25% Comp. model: S350 (W220) = 10.9 l/ 100km	-20% Comp. model: S 400 CDI (W220) =9.6 l/100km
Accel. 0-100 km/h or  0-60 mph	7.5 sec	7.2 sec
Ignition time	<0.3 sec	<0.3 sec
Top speed (km/h), electronically limited	250	250