BMW Hydrogen 7

The Hydrogen 7 is a hydrogen- powered car. He carries the internal designation E68 and is based on the model 760Li ( E66 ) from the 7-series of the German manufacturer BMW.

A special feature of the Hydrogen 7 is powered by a hydrogen internal combustion engine. In addition, it can be switched over to petrol drive, with which the vehicle is to be practical for everyday use, since it only 14 publicly accessible hydrogen filling stations (May 2013) in Germany are. For this he needs an additional fuel tank. At the BMW plant in Dingolfing, 100 units of this model were made ​​, which were not sold, but only leased.

The Hydrogen 7 has two predecessors: One of the first hydrogen-powered vehicles worldwide were among those built in the year 2000 15 Single copies of type 750hL on the basis of the then 750i ( E38 ). They were used, among other things at the Expo 2000. The experience with the hydrogen prototype H2R in 2004 were incorporated into the development of the Hydrogen 7.

Motor

The hydrogen combustion engine of the Hydrogen 7 is technically almost identical to the engine of the 760i. He had to be modified for the use of hydrogen as a fuel though. The modifications relate mainly to the intake of the engine. In addition to the direct injection of gasoline a supply line to the hydrogen tank was integrated. Special injection valves always ensure the correct amount of hydrogen in the intake air.

Also the sealing of the piston rings had to be improved in order to prevent leakage of the hydrogen. This had resulted in earlier development stages again and again to explosions. As hydrogen burns faster times compared with conventional fuels, up to 100, the engine control system had to be adapted. Valvetronic and Double -VANOS offered the ideal conditions here. Valve opening times and valve timing can be optimally adjusted to the new requirements.

The engine of the Hydrogen 7 makes final 191 kW (260 hp) and a peak torque of 390 Nm (compared to the " normal" 760i makes 327 kW/445 hp and 600 Nm). From 0 to 100 km / h, the car needs 9.5 s The performance is compared to the 760i due to the bivalent configuration of the engine lower. With a full tank of 8 kg, it is about 200 km. With the fuel tank (74 l) he comes in addition once more 500 km. Since it is the Hydrogen 7 is a bivalent engine concept (that is, the motor can be operated on both hydrogen and gasoline ), an improvement in a monovalent principle ( an exclusively hydrogen-fueled engine ) is quite possible.

Other conversions

In addition to the changes to the engine and the trunk had to be changed: For the storage of hydrogen, an additional tank had to be built. The development and the subsequent series production of the tank was carried out by Magna Steyr vehicle technology in Graz / Austria. This tank reduces the usable trunk space of 500 liters to 250 liters This tank is the hydrogen at about 20 K in the low pressure region ( the boiling point of hydrogen is -252.882 ° C) stored in liquid form. The development was characterized among other things by the use of media materials suitable for cryogenic operating conditions. Further, the permeation of hydrogen presented a major challenge to insulation of the tank, a high vacuum was pulled between the inner and outer tank. The interior walls are lined with a suitable insulating material. The production was carried out, among others, under clean room conditions. The associated electronics and sensors for the measurement of the filling material and for monitoring the safety filling level in the refueling was presented a challenge in the development represents the company Atena Engineering (now Silver Atena Electronic Systems Engineering ) therefore developed the control unit, which handles the safety functions in accordance with the safety standard IEC 61508. Known as the life stage to the controlled evacuation of a half-filled hydrogen tank begins after 17 hours and is about 9 days. Then would remain in the tank sufficient hydrogen to travel still about 60 kilometers distance in the hydrogen mode. This isolation corresponds to about 17 m thick polystyrene foam.

The interior had to be changed a bit: The back seat was shifted by 12 cm forward and find it on her only two people, as the center armrest has been locked. Furthermore, the framework and crash zones were reinforced by composites.

Hydrogen 7 is in a more curved hood to see the lack of fog lights and the additional filler to the C-pillar.

Field trial

As "0 -liter car " in 2002 announced by BMW series production., Which was classified as greenwashing. So wrote Der Spiegel 46/2006:

" The supposed Ökomobil arg is thirsty - and charged the air like a heavy truck "

Because at the BMW statement, the expenditure for the production and liquefaction of the hydrogen remains fully taken into account in addition to the non-availability of hydrogen fueling stations. Thus, in the H2 - consumption (3.6 kg/100 km ) a gasoline equivalent is led by 13.3 l/100 km. However, besides the above -mentioned expenses for the provision of energy ( hydrogen production currently almost exclusively by steam reformation of natural gas) is also worth mentioning that self- emptied during idle time of the vehicle ( see prior to discharging time ) of the tank. The units produced 100 were not sold, but partially to celebrities (such as Plácido Domingo, Daniel Barenboim, Katja Riemann, Florian Henckel von Donnersmarck ), politicians (eg Günter Verheugen, Christian Ude, Guido Westerwelle ) and business representatives ( based on leasing handed over for use, for example, Roland Berger, Wolfgang Reitzle ). A part of the fleet was used in profile events as a train. So were during the field trial in Berlin constantly between five and ten vehicles in use, which were fueled at the then existing two hydrogen filling stations at fair dam and on the highway. On special occasions, such as during the Berlinale, the number of Hydrogen 7 in Berlin rose to around 20 The field trial was terminated in late 2009, the whereabouts of 100 vehicles is not known.

Next steps of development

BMW has announced the end of 2009, that at the present time, no new fleet of hydrogen vehicles is planned, as this would bring no new information after the experience with the Hydrogen 7.