1. Alternative drive systems at Daimler AG for the mobility of the future

2. Alternative drive systems at Daimler AG

3. Hybrid vehicles - several drive systems on board

4. Electric motors as an alternative to combustion engines

5. Fuel cell - moving towards a zero-emission future

6. Using better fuels, achieving cleaner combustion and higher performance

7. Advancements with other internal combustion machines

8. Timeline: Alternative drive systems at Mercedes-Benz

Electric motors as an alternative to combustion engines

• 1898: The first electric automobile in the history of Daimler AG
  
  
• In more recent times, electrically powered vans have been produced, as well as passenger cars with this environment-friendly drive system´
  
  
• Further development of battery technology
  
  

Around the turn of the twentieth century, the gasoline engine was by no means without its rival systems. Individual motorization with the automobile experienced an initial boom, and a range of different designs competed for buyers. The electric motor was touted as an alternative to the internal combustion engine as a power source for the automobile. The Berlin-Marienfelde motor vehicle and engine factory, the forerunner of the Mercedes-Benz Berlin plant, produced its first electric vehicle as early as 1898. Its partner in the project was the American Columbia Electric Company in Connecticut, which continued to build electric automobiles up to 1918. The license agreement with the Berlin plant, formerly the Altmann & Cie. GmbH company, was signed in 1897.

In 1899, the Berlin-Marienfelde motor vehicle and engine factory offered four different passenger cars based on the American patent. The motor, whose battery was installed in a box underneath the passenger compartment, transferred its power to the rear axle via a gearwheel drive. The “electric coach” weighed 1,800 kilograms, had a range of 40 kilometers, required 0.34 kilowatt hours per kilometer, coped with inclines of up to seven percent, and cost 9,300 marks.

The car was particularly well suited to the city, according the manufacturer’s advertising text in 1899: “While motor vehicles operating on gasoline, steam, etc. represent what could be termed the strong and powerful, bourgeois-artisan manifestation of this form of transportation, built to withstand continual, repeated jolts, transport heavy loads, and travel long distances on country highways with a more or less adequate seal, electric vehicles meet the more aristocratic task of transporting people through busy streets in big cities, without noise or smell, faster, more pleasantly, and more comfortably than the best team of horses could pull a luxury coach.” The Berlin-Marienfelde motor vehicle and engine factory also supplied small buses and trucks with the environment-friendly drive system.

However, the electric motor built according to the Columbia Electric system was unable to keep up with the rapid development of the internal combustion engine. Production was discontinued in Berlin-Marienfelde in 1902. In the same year, in a resolution on August 16, Daimler-Motoren-Gesellschaft merged with the Berlin-Marienfelde motor vehicle and engine factory.

A Mercedes with electric drive

The first electrically powered Mercedes was built five years later in Vienna, and was not seen as anything unusual at all, but rather as a serious alternative to the combustion engine. A contemporary report about the Automobile Exhibition in Vienna in spring 1907 had this to say: “The elegance of the electric city vehicle is perfectly illustrated by several Mercedes-Electriques which attracted great attention at the exhibition.” In the same year, Allgemeine Automobil-Zeitung (AAZ) automotive newspaper wrote: “Our readers know that the Mercedes company is now also producing electric automobiles, using the Lohner-Porsche system, unquestionably the best system in the world.” The Mercedes-Electrique vehicles were used in particular as fire engines and buses. The advantages they offered were that they were always ready to start promptly, and were relatively cheap to run. This was because mechanical components, such as transmissions, clutches or chains were no longer needed to transfer the power, thanks to electric wheel hub motors.

In a similar vein, the operating instructions for the Mercedes-Electrique were full of praise for the system: “For this reason, the electric Daimler is extremely economical to operate, and offers the maximum guarantee of operating safety; in addition, it requires the smallest imaginable amount of maintenance, and is so easy to operate that its operation can be mastered in next to no time by non-specialists such as coachmen, etc.” The principal drawbacks of the system were a short range and the considerable weight of the battery sets.

In 1908, for example, the Berlin fire brigade decided to deploy electric vehicles, when a new platoon comprising four Mercedes-Electrique vehicles came into service (gas pump, steam pump, tender and mobile turntable ladder). Due to the short range of the electric vehicles, however, the firefighters ordered a second steam-powered platoon for call-outs in the country.

Vans bring the electric drive system up to date

The first concept for a modern electrically-powered van at
Mercedes-Benz was created in 1972 - the LE 306. The engine developed 31 kW (42 hp), achieved a maximum speed of 70 km/h, and had a range of 65 kilometers. A press release issued on the occasion of the vehicle presentation stated that the battery could be “recharged during breaks or replaced using what is known as push-through horizontal-exchange technology. This procedure, which to a large extent can be automated, takes no more than the time needed to fill up a vehicle’s tank.”

Three vehicles were initially built and operated for test purposes, while the LE 306 was also used at the 1972 Munich Olympic Games. In the years that followed, a total of 89 electric vans clocked up some 2.9 million kilometers between themselves in test drives. In a first conclusion, the system was recommended in November 1975 for urban distribution vehicles covering less than 100 kilometers a day. For longer distances, however, a serial hybrid drive was planned using a diesel engine as an energy source; in sensitive areas, however, such as inner city zones, the hybrid van was to be powered by lead batteries. The costs, particularly for the batteries, argued against any large-scale production launch.

In 1975, the Research unit came up with the duo bus. This was based on the Mercedes-Benz OE 302, but had an all-electric drive system with dual energy supply: the propulsion energy came either from an underfloor battery or flowed into the vehicle from overhead wires (hence the name “O-Bus”). This gave it a degree of flexibility independent of the wire network. Although the range when operating solely on battery power was greater, it was recommended to return to overhead-wire operation after ten kilometers, which would simultaneously recharge the vehicle’s battery. When the vehicle braked, energy was fed back into the battery. Advances had already been made in terms of the battery weight, which at 15 percent of the gross vehicle weight was described as “relatively low.” The duo bus was presented in Esslingen in April 1975, and on the same day it started out on an extensive public transport test program with the aim of achieving reliable and economical operation. It had 37 seats and room for 45 standing passengers. In mid-1976, at the end of the specified test period, the duo bus was taken out of service again. For the town of Esslingen, however, the trolley bus was there to stay.

The next generation of the duo bus was presented in 1979. Three prototypes illustrated different power supply options: in one variant, the Mercedes-Benz O 305 took its traction energy from either the overhead wires or the onboard batteries, in a second variant from either the overhead wires or a conventional diesel engine. Variant number two was also tested in an articulated bus offering greater passenger-carrying capacity. In each case, the bus was able to free itself from the rigid link to the overhead wires and drive independently. The major benefit of the O 305, operating on electric power only, was zero emissions wherever it was deployed. The diesel-electric O 305, on the other hand, offered even greater flexibility. Once again, the town of Esslingen participated in regular-service testing.

Production maturity of electric drive systems moves closer
In October 1980, at the “Drive Electric ’80” exhibition in London, Daimler-Benz presented the electric 307 E van. The principal aim in development was to reduce the manufacturing and operating costs. The control engineering had been simplified, and vehicle handling in everyday operation was no different from that of a van with an internal combustion engine. Tests with the LE 306 set up in 1972 showed that, in most cases, battery exchange technology, which requires expensive special equipment, was not necessary. The energy storage unit in the 307 E was arranged in two rows under the vehicle floor. There was also an integrated lifting device, allowing the batteries to be simply removed from below. The loading space corresponded exactly to that of the production van with an internal combustion engine, while the payload capacity was 1.5 tons.

A large-scale test with 22 Deutsche Post (German Mail) vans in Bonn in 1983 showed that all-electric vans incurred energy costs that were roughly double those of vehicles with diesel engines. However, the local zero emissions from the electric vehicles made the high costs worthwhile for specific applications.

In 1982, Mercedes-Benz commenced production of the O 305 GT trolley bus for all-electric drive, with power supply from overhead wires. It was manufactured in Switzerland in collaboration with FBW and Sécheron. Its electric motor developed 169 kW (230 hp) and drove the rear axle. In traffic, compared with trams, the O-Bus had the advantage that it was not physically bound to one track and could deviate up to three meters to the side in order to avoid obstacles. If there were problems with the overhead wires, it was possible to switch on an emergency unit so that the bus could continue under its own power; a gasoline engine developing 37 kW (51hp) and a flange-mounted generator then supplied the drive energy.

First passenger cars with electric drive

In early 1982, Mercedes-Benz began testing an electric drive system for passenger cars. The research car based on the 123-series station wagon model had a novel drive concept. A single module comprised a DC drive motor (continuous output 25 kW/34 hp, peak output 32 kW/44 hp), a multiple-disc start-up clutch, automatic transmission (derived from a passenger car automatic transmission), an encapsulated upstream two-cylinder internal combustion engine (10 kW/14 hp) as emergency drive system, and an intermediate centrifugal clutch. The modified trunk housed a newly designed nickel-iron battery, from which the researchers hoped to achieve double the energy content per weight unit than from a lead battery. In terms of ride comfort and equipment, the car matched the current production configuration for the model series; only the trunk volume was limited because the battery was housed there, resulting in a reduced payload. The car’s range was about 100 kilometers.

In 1985, a solar vehicle from Mercedes-Benz and Alpha Real proved itself in the “Tour de Sol” rally. It was ultra-light and featured solar panels on the roof to generate the drive energy. The test model thus came very close to achieving the ideal of an independent electric vehicle.
The “transport ’88” exhibition in Munich saw the premiere of the O 405 T trolley bus. Like the O 405 GTD duo bus, it featured novel electric drive technology that Daimler-Benz had jointly developed with Dornier and AEG.

As battery technology was constantly moving towards smaller and more powerful units, Mercedes-Benz launched the first vans with electric drive onto the market in 1988. The 308 E (T1 series), for example, was used in the cities of Mainz, Düsseldorf and Stuttgart as refuse collection vehicles in inner city zones. It featured a direct-current series-wound motor with an output of 18 kW (24 hp), allowing a top speed of 46 km/h and a range of up to 60 kilometers. Similarly, the MB 100 E and large-capacity vans from the T2 series were offered with electric drive. The vehicles were fitted with tried and tested maintenance-free lead-gel batteries.

A Mercedes-Benz 190 (201 series) was the basis for another electric test car that was presented to the public in 1991. In this case, two electric motors excited by permanent magnets, each with a maximum output of 16 kW (22 hp), directly drove the rear axle. No transmission was needed because of the high torque across the entire revolving speed range; this meant that the powertrain could be omitted, and the associated losses did not occur. The light and compact design created space and saved on weight. However, this solution was more expensive than a conventional DC motor. Not only a battery was accommodated under the engine hood of this “mobile laboratory” but also a host of electronic equipment for controlling the drive system. A second battery and measuring equipment took up almost the entire trunk space, and this represented an improvement; before this 190 model, there had been test cars with DC motors whose batteries occupied the trunk and part of the rear seat bench area, leaving room for only three people in the car.

In 1992, a demonstration project that was planned to run for four years was started on the island of Rügen to test the latest generation of electric vehicles, in order to gain information about their practicality under realistic conditions. A total of 60 passenger cars and small vans from various manufacturers were used. From Mercedes-Benz, ten advanced 190 and MB 100 units with different kinds of electric-motor-and-battery combinations took part. The vehicles were charged from normal electric sockets and also at gas stations specially equipped with recharging stations where the electricity was generated in part by solar cells.

At the 1993 Olympic Games in Barcelona, the MB 100 E was deployed as a back-up and transport vehicle. It was fitted with a DC shunt-wound motor, delivering 28 kW (38 hp) and allowing a top speed of 80 km/h with a maximum range of 80 kilometers.

Testing of electric drive systems continued. 1993 saw a prototype based on the C-Class (202 series) powered by an asynchronous electric motor (35 kW/48 hp). Zebra high-energy batteries from AEG gave the concept car a range of 110 kilometers. The engineers accommodated all the technology in the car so skillfully that the electrically powered Mercedes-Benz had almost the same amount of space as a standard C-Class sedan. The payload capacity was still a good 370 kilograms. The safety level was identical with that of a standard C-Class.

Battery technology keeps pace

The maintenance-free Zebra high-energy battery was one of the most promising energy storage units for electric automobiles. The electrochemical reaction took place at a temperature of between 260 and 350°C (500 – 660°F), which meant that it was necessary to heat the hermetically sealed and thermally insulated battery cells electrically. A microcomputer handled temperature control. The Zebra battery, with roughly four times the capacity of a standard lead battery, had a remarkably long life. Experts estimated that a vehicle fitted with a Zebra battery could travel well over 100,000 kilometers.

A comparison with an electric prototype of the Mercedes-Benz 190 developed in 1989 clearly illustrated the level of progress that the researchers had achieved: the earlier test car was fitted with a sodium/nickel chloride battery, allowing a range of approximately 100 kilometers with a maximum energy content of 27.5 kilowatt hours under city driving conditions. However, the engineers could achieve these values only by using a large, single-piece battery which, in contrast to the new electrically powered C-Class, took up almost all of the rear seat area and the trunk of the sedan.

The drive system also differed from the more recent electric prototype from Daimler-Benz: the 190 Electric was fitted with a 19 kW (26 hp) DC shunt-wound motor whose maximum torque of 125 Nm was transferred to the rear wheels via a five-speed manual transmission. In this way, the prototype of 1991 accelerated from standstill to 50 km/h within 13 seconds and achieved a top speed of 110 km/h. The C-Class had an asynchronous motor with an output of 20 kW (27 hp, peak output: 35 kW/48 hp) and a maximum torque of 170 Nm. The car required nine seconds to accelerate from a standstill to 50 km/h and had a top speed of 120 km/h.

Over the next few years, more than 60 experimental vehicles powered by Zebra high-energy batteries were produced, for example the 108 E based on the Vito van (600 kilogram payload, range between 110 und 175 kilometers). An A-Class followed in 1998 (range 160 to 200 kilometers, with an electronically controlled top speed of 130 km/h) that had been specifically chosen for this type of application: its sandwich floor offered the ideal installation space for alternative drive systems, and illustrated that the latter could be accommodated even in such a compact car. There were no restrictions on the interior space, and it was possible to fully utilize the trunk space.

At the Commercial Vehicle Show in Hanover in September 1994, Mercedes-Benz presented the prototype of the O 405 GNTD, a low-floor duo bus with diesel engine and electric wheel hub drive.

In 1998, Mercedes-Benz unveiled the production version of the Cito bus at the Commercial Vehicle Show. Following the design of the duo buses, it had a diesel-electric drive system - with a four-cylinder engine driving a generator whose power was transferred to the propulsion motor. The result was smooth, completely jolt-free acceleration, something that was impossible to achieve with a purely mechanical powertrain. The configuration offered extra space for reserve batteries, allowing zero-emission operation in city centers.

In July 2006, a pilot project for the smart brand, which forms part of the Mercedes Car Group, was launched in the U.K. From November, the smart fortwo ev (electric vehicle) was deployed there for everyday use; in 2007, the model was renamed fortwo ed (electric drive). The company provided approximately 100 units as lease vehicles to selected British customers. The model was powered by an electric motor with an output of 30 kW (41 hp). The battery used sodium-nickel chloride technology. In London, the smart fortwo ev was exempted from the inner-city congestion charges, and its operating costs were well below those for a smart with gasoline engine: fuel costs amounted to 0.02 euros as against 0.06 euros per kilometer. Acceleration to 60 km/h was roughly the same as with the gasoline version. The top speed was 120 km/h with a range of 110 kilometers. The figures spoke for themselves: the electric smart was a car that was ideal for traveling short distances in city traffic.

A predecessor to the smart in terms of overall concept, the NAFA (German abbreviation for short-radius car) concept study presented by Mercedes-Benz in 1981, was incorporated in plans for alternative drive systems as early as the mid-1980s. At the time, schemes included not only housing an electric drive, but also fitting a storage tank for hydrogen as the fuel for a spark ignition engine.
Incidentally, automobiles with a fuel cell as the drive system of the future also include electric vehicles, i.e. those with an onboard powerplant for producing electrical energy. This energy is generated from hydrogen in a chemical reaction on board the vehicle.

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	Group photo: In the 1970s and 1980s, Mercedes-Benz tested different propulsion concepts – with a correspondingly large fleet of test vehicles. The photo was taken on the test track in Stuttgart-Untertürkheim in 1981.
	Group photo: In the 1970s and 1980s, Mercedes-Benz tested different propulsion concepts – with a correspondingly large fleet of test vehicles. The photo was taken on the test track in Stuttgart-Untertürkheim in 1981.
	Mercedes Electrique: “The most reliable, quietest and most modern electric city car.” Advertisement of 1907.
	Rapid start: In 1908, the Berlin fire brigade opted for the Mercedes Electrique with electric drive and purchased a fleet consisting of four vehicles. The wheel hub motors in the front wheels are clearly visible.
	Mercedes Mixte on the front cover of the magazine “La France Automobile”, edition of November 9, 1901.
	Environment-friendly electric drive: The Mercedes-Benz LE 306 of 1972 featured a battery exchange system which accelerated the “refueling”. The vehicle was extensively tested.
	Environment-friendly electric drive: The Mercedes-Benz LE 306 of 1972 featured a battery exchange system which accelerated the “refueling”. The vehicle was extensively tested.
	Environment-friendly electric drive: The Mercedes-Benz LE 306 of 1972 featured a battery exchange system which accelerated the “refueling”. The vehicle was extensively tested.
	Environment-friendly electric drive: The Mercedes-Benz LE 306 of 1972 featured a battery exchange system which accelerated the “refueling”. The vehicle was extensively tested.
	Ready for boarding: Mercedes-Benz city bus with hybrid electric drive of 1979. The internal combustion engine powered a generator which produced electricity for the traction motor.
	Ready for boarding: Mercedes-Benz city bus with hybrid electric drive of 1979. The internal combustion engine powered a generator which produced electricity for the traction motor.
	Ready for boarding: Mercedes-Benz city bus with hybrid electric drive of 1979. The internal combustion engine powered a generator which produced electricity for the traction motor.
	Diesel-electric operation in cities: In the Mercedes-Benz Cito (1998), a four-cylinder engine powered a generator which produced electricity for the traction motor. Purely electric operation was possible over short distances.
	Diesel-electric operation in cities: In the Mercedes-Benz Cito (1998), a four-cylinder engine powered a generator which produced electricity for the traction motor. Purely electric operation was possible over short distances.
	Energy providers: The Mercedes-Benz OE 302 electric test bus (1969) needed five battery modules which were installed underneath the floor.
	Diesel-electric: The Mercedes-Benz OE 302 test city bus was powered by electricity, its batteries being charged by a diesel engine. This vehicle marked a new start in hybrid drive development in 1969.
	No clutch pedal: The driver of the Mercedes-Benz OE 302 electric test bus (1969) only had to actuate the accelerator and brake with his feet.
	Diesel-electric: The Mercedes-Benz OE 302 test city bus was powered by electricity, its batteries being charged by a diesel engine. This vehicle marked a new start in hybrid drive development in 1969.
	Early example of an electric car: The chassis of the 30/35-hp Mercedes with wheel hub motors (built from 1905 until 1909).
	Refueling at the mains: Two Mercedes-Benz test vehicles with electric drive, photographed in 1995.
	Testing in the early 1990s: Mercedes-Benz MB 100 D van with electric drive; a city bus version of this model was also set up.
	Large-scale electric-drive test on the island of Rügen in 1992: Mercedes-Benz contributed ten 190 cars and ten MB 100 D vans.
	Large-scale electric-drive test on the island of Rügen in 1992: Mercedes-Benz contributed ten 190 cars and ten MB 100 D vans.
	Emissionsfrei unterwegs: Der in Serie gefertigte Duo-Bus, hier ein Exemplar aus dem Jahr 1993, hat einen reinen Elektroantrieb mit doppelter Energiezufuhr. Die Antriebsenergie kommt entweder aus einer Unterflur-Batterie oder gelangt per Oberleitung ins Fahrzeug („O-Bus“). Das bringt Flexibilität abseits des Leitungsnetzes.
	Transparency: The X-ray picture of a Mercedes-Benz C-Class with electric drive of 1993 shows the layout of components.
	Large-scale electric-drive test on the island of Rügen in 1992: Mercedes-Benz contributed ten 190 cars and ten MB 100 D vans.
	Test car with ZEBRA battery: Mercedes-Benz 190 with electric drive, 1993.
	Large-scale electric-drive test on the island of Rügen in 1992: Mercedes-Benz contributed ten 190 cars and ten MB 100 D vans.
	Novel electric drive: The Mercedes-Benz 190 used as a test car in 1991.
	Novel electric drive: The Mercedes-Benz 190 used as a test car in 1991.
	Large-scale electric-drive test on the island of Rügen in 1992: Mercedes-Benz contributed ten 190 cars and ten MB 100 D vans.
	Zero-emission motoring in the city: In July 2006, the smart brand launched a pilot project in London. The fortwo ed (electric drive) generates an output of 30 kW (41 hp) for adequate performance and has a range of some 100 kilometers (62 miles).
	Zero-emission motoring in the city: In July 2006, the smart brand launched a pilot project in London. The fortwo ed (electric drive) generates an output of 30 kW (41 hp) for adequate performance and has a range of some 100 kilometers (62 miles).
	High level of ride comfort: In early 1982, Mercedes-Benz began testing electric drive systems in passenger cars. The station wagon from the 123 series largely corresponded to the production version but its load compartment was reduced in size by the fact that it accommodated the battery.
	High level of ride comfort: In early 1982, Mercedes-Benz began testing electric drive systems in passenger cars. The station wagon from the 123 series largely corresponded to the production version but its load compartment was reduced in size by the fact that it accommodated the battery.
	High level of ride comfort: In early 1982, Mercedes-Benz began testing electric drive systems in passenger cars. The station wagon from the 123 series largely corresponded to the production version but its load compartment was reduced in size by the fact that it accommodated the battery.
	Testing in city traffic: Mercedes-Benz 307 E van with electric drive (1980).
	On the test track in Stuttgart-Untertürkheim: Mercedes-Benz 307 E van with electric drive (1980).
	Propulsion energy at times of hardship, available ex factory: Mercedes-Benz 170 VG (1935) with wood gas burner.
	Mercedes-Benz L 307 van of 1975: Test vehicle with hydrogen propulsion and hydride storage unit.
	Test bus of 1971: The six-cylinder spark-ignition engine of the Mercedes-Benz OG 305 operated on natural gas – with very low pollutant emissions.
	Prototype with electric drive: The Mercedes-Benz A-Class (W 168 series) of 1998 derived its energy from a ZEBRA high-performance battery on a sodium/nickel chloride basis.
	In 1992, Mercedes-Benz presented a “Flexible Fuel” test car based on the 300 SE S-Class model (140 series). It engine management was designed for variable mixed methanol/ gasoline operation with a methanol proportion of up to 85 percent.
	Adjustable engine management: In 1990, Mercedes-Benz presented the 300 E-24 for variable mixed methanol/gasoline operation.
	Special setup: The Mercedes-Benz 450 SL test car (R 107 series) of 1974 had a spark-ignition engine optimized for operation on methanol. The engineers used the console and additional switches for controlling and monitoring the fuel system.
	Three test vehicles from Mercedes-Benz (from left to right): LE 306 electric van (1972), OE 302 electric test bus (1969), OG 305 natural-gas test bus (1971).
	Energy carrier for the future: In 1988, hydrogen was tested as a fuel in Mercedes-Benz vans and passenger cars.
	Mercedes-Benz 200, 1981: Test car for the combined supply of the internal combustion engine with gasoline and liquefied gas.
	Methanol operation and energy recuperation: The Mercedes-Benz O 305 test city bus on the test track in Stuttgart-Untertürkheim (1981). The vehicle was also tested in regular service.
	Environment-friendly vehicles: Mercedes-Benz city bus with electric drive, van with electric drive and passenger car (123 series) for mixed methanol/gasoline operation. The photo was taken around 1980.
	Methanol as a fuel: In 1979, the Federal German Ministry of Transport launched a research project named “Alternative Energies for Road Traffic”. Mercedes-Benz participated in a field test in Berlin with different vehicles, among them the 230 model (123 series).
	Methanol as a fuel: In 1979, the Federal German Ministry of Transport launched a research project named “Alternative Energies for Road Traffic”. Mercedes-Benz participated in a field test in Berlin with different vehicles, among them the 230 model (123 series).
	Gratifyingly low emissions, more efficient power output: The Mercedes-Benz 450 SL test car (R 107 series) with a spark-ignition engine optimized for operation on methanol was presented to the public in 1974.
	B-Class F-Cell
	NECAR 1, 2 and 3: From van to A-Class.
	Mercedes-Benz Concept Vehicles, NECAR 1: An MB 100 van served as basis.
	Mercedes-Benz Concept Vehicles, NECAR 1: The cargo space is packed with equipment. The stacks are arranged beneath the yellow hydrogen flask.
	The Technology of the Fuel Cell and its Operating Systems, The operating principle of the fuel cell.
	Matured: After the completion of the test stage, several units of the NGT Sprinter (Natural Gas Technology) were put into service, for instance by RHENAG in April 1996.
	Matured: After the completion of the test stage, several units of the NGT Sprinter (Natural Gas Technology) were put into service, for instance by RHENAG in April 1996.
	In 1992, Mercedes-Benz presented a “Flexible Fuel” test car based on the 300 SE S-Class model (140 series). It engine management was designed for variable mixed methanol/ gasoline operation with a methanol proportion of up to 85 percent.
	Hydrogen testing: Mercedes-Benz also investigated the suitability of hydrogen as an energy supplier for internal combustion engines in vans.
	On the way into the future: Different vehicles – the photo shows a Mercedes-Benz 230 E – were used in 1993 for testing hydrogen as a fuel for the internal combustion engine.
	On the way into the future: Different vehicles – the photo shows a Mercedes-Benz 230 E – were used in 1993 for testing hydrogen as a fuel for the internal combustion engine.
	Production car: In March 2006, smart presented the forfour lpg (liquefied petroleum gas) with a liquefied-gas tank in addition to the gasoline tank. In combined operation, the car has a range of 1,300 kilometers (over 800 miles).
	Production car: In March 2006, smart presented the forfour lpg (liquefied petroleum gas) with a liquefied-gas tank in addition to the gasoline tank. In combined operation, the car has a range of 1,300 kilometers (over 800 miles).
	Production car: In March 2006, smart presented the forfour lpg (liquefied petroleum gas) with a liquefied-gas tank in addition to the gasoline tank. In combined operation, the car has a range of 1,300 kilometers (over 800 miles).
	Spectacular test car: The Wankel or rotary-piston engine was tested in the Mercedes-Benz C 111-I (1969, shown in the photo) and C 111-II (1970).
	Spectacular test car: The Wankel or rotary-piston engine was tested in the Mercedes-Benz C 111-I (1969, shown in the photo) and C 111-II (1970).
	On the way into the future: Different vehicles – the photo shows a Mercedes-Benz 230 E – were used in 1993 for testing hydrogen as a fuel for the internal combustion engine.
	V8 gasoline engine with cylinder shutoff, six-cylinder diesel engine with turbocharger, gas turbine: The Mercedes-Benz Auto 2000 research car (1981) was used for testing these three propulsion systems.
	V8 gasoline engine with cylinder shutoff, six-cylinder diesel engine with turbocharger, gas turbine: The Mercedes-Benz Auto 2000 research car (1981) was used for testing these three propulsion systems.
	V8 gasoline engine with cylinder shutoff, six-cylinder diesel engine with turbocharger, gas turbine: The Mercedes-Benz Auto 2000 research car (1981) was used for testing these three propulsion systems.
	V8 gasoline engine with cylinder shutoff, six-cylinder diesel engine with turbocharger, gas turbine: The Mercedes-Benz Auto 2000 research car (1981) was used for testing these three propulsion systems.
	V8 gasoline engine with cylinder shutoff, six-cylinder diesel engine with turbocharger, gas turbine: The Mercedes-Benz Auto 2000 research car (1981) was used for testing these three propulsion systems.

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