BMW Hydrogen 7 Revealed

Press Release

BMW Hydrogen 7: paving the way into the future

Launching BMW Hydrogen 7, the BMW Group is opening up a new era for the development of automobiles with alternative drive technologies: BMW Hydrogen 7 is not the result of a research project, but has rather successfully completed the entire Product Development Process (PDP) obligatory for all new BMWs.

In this process all components of the new technology were integrated into the overall vehicle according to the same criteria applied to “regular” production cars. Hence, BMW Hydrogen 7 has reached a level of development significantly beyond the status of all hydrogen prototypes and demonstration cars built so far and allowing homologation under the usual rules and standards in both Germany and the ECE.

The knowledge gained in the Product Development Process has not only made a decisive contribution to the everyday driving qualities of the BMW Hydrogen 7, but has also had a positive effect on the features and qualities of all individual components. In the Product Development Process each and every component as well as the overall vehicle is analysed and checked to the smallest detail, determining whether it meets the requirements of series production.

Representing firm features in the Product Development Process, the individual process steps in Development, Testing, Clearance and Signing-Off guarantee the high standards demanded of a BMW Group vehicle. Naturally, the process takes all criteria relevant to the customer into account in order to verify that the new product is ready for the market in every respect. For only then are the conditions fulfilled for presenting the customer – as with all other BMW models – with the world’s first luxury saloon running with a hydrogen combustion engine.

Entering the market as the first hydrogen car for everyday use, the BMW Hydrogen 7 is a milestone – and at the same time it introduces a new era in car production. The knowledge gained in developing the car will have a significant influence on the development and production of future hydrogen car concepts, with the principle of dual-mode drive as well as the features of other components now going through the strict test of everyday driving practice.

Liquid hydrogen – the energy of the future

Ever since the start of research and development in this area, the BMW Group has given preference to the use of liquid hydrogen as the appropriate source of energy for the automobile. Compared with gaseous and highly compressed hydrogen, liquid, cryogenic hydrogen offers much higher energy density.

And comparing the amount of energy stored in a tank of the same size as cryogenic, liquid hydrogen as opposed to a car tank with gaseous hydrogen compressed to 700 bar, we see that liquid hydrogen has the advantage of offering 75 per cent more energy. Clearly, therefore, a vehicle running on liquid hydrogen has a correspondingly longer cruising range with all the practical benefits involved.

Dual-mode combustion engine for enhanced flexibility

In judging the everyday qualities of a new drive concept, the practical cruising range offered by a car is one of the most important criteria. But apart from consumption figures and the tank capacity in a car, we must also consider the existing fuel supply infrastructure.

Right now there is not yet a full network of hydrogen filling stations. Hence, vehicles running on hydrogen alone can only be used within certain limits on public roads and do not offer the flexibility naturally expected by the customer.

Precisely this is why the BMW Group, introducing the world’s first hydrogen car for everyday use, is opting for dual-mode drive technology, with the combustion engine of BMW Hydrogen 7 being able to run on both hydrogen and gasoline.

The cruising range of the car in the hydrogen mode is more than 200 kilometres, with another 500 kilometres in the gasoline mode. As a result, the driver of a BMW Hydrogen 7 benefits from virtually unlimited mobility and is able to use his vehicle without problems even when far away from the nearest hydrogen filling station.

Dual-mode drive technology – the key to everyday motoring

The prerequisite for permanent use of hydrogen as a source of energy is a closely-knit network of hydrogen filling stations. On the other hand there will only be an incentive to build additional filling stations when a significant potential for vehicles with hydrogen drive is obviously developing in the market.

Precisely this is why BMW Hydrogen 7 is destined to become a pacemaker for progress on both levels. It now generates the momentum required for expanding the right fuel supply infrastructure, ultimately benefiting those car makers focusing exclusively on single-mode hydrogen technology. For once the number of hydrogen filling stations increases accordingly, these vehicles will also become more attractive, single-mode hydrogen vehicles then offering the same everyday driving qualities and practical benefits that BMW Hydrogen 7 is already able to prove today.

Opting for this dual-mode drive concept, the BMW Group is consciously acting as a pacemaker. Indeed, this commitment to set standards not only to the benefit of BMW’s own customers, but also to the advantage of an entire world of technology, is part of the responsibility the BMW Group is happy to assume in our modern world.

Fuel cell technology BMW style: the APU

Despite this clear focus on hydrogen technology, the BMW Group is also working consistently on the fuel cell to ensure practical use of this technology also in the automobile. The long-term objective is to use the fuel cell as an auxiliary power unit (APU) both in the hydrogen and gasoline car, the APU serving to supply electric power for the on-board network both while driving and at a standstill.

V12 power unit developing dynamic performance BMW style from hydrogen

Under current conditions, dual-mode drive is indeed the only really practical solution in giving hydrogen the breakthrough it deserves. And at the same time the combustion engine featured in BMW Hydrogen 7 is excellently suited for arousing widespread acceptance of this new technology.

Particularly in comparison with the fuel cell, the power unit featured by BMW develops much more engine power, the V12 driving BMW Hydrogen 7 combining dynamic performance, superior comfort and enhanced safety in a manner typical of all BMWs, regardless of the type of fuel or engine technology.

Displacing 6.0 litres, the power unit develops maximum output of 191 kW. Maximum torque, in turn, is 390 Newton-metres at an engine speed of 4,300 rpm. This enables BMW Hydrogen 7 to accelerate from a standstill to 100 km/h in 9.5 seconds and gives the car an electronically limited top speed of 230 km/h, both on hydrogen and gasoline.

Right from the start, therefore, this alternative energy technology brand-new in a series production car is absolutely equal to the gasoline engine with its history of more than 100 years. So the conclusion is clear: A hydrogen car is also able to offer power, performance, driving dynamics, motoring refinement and, as a result, sheer driving pleasure of the supreme standard expected of a genuine BMW.

Apart from the driving experience, the twelve-cylinder power unit carried over from the BMW 760i as the basis for the engine in BMW Hydrogen 7 offers further benefits highly relevant to the customer. Indeed, the engine comes with all the qualities gained by BMW in decades of experience in the production of particularly powerful and efficient power plants, which also means the supreme reliability so typical of a BMW.

Compared with a fuel cell hardly able to offer the same kind of power, the combustion engine is far lighter right from the start. A further point is that use of a combustion engine also means lower cost of production, with BMW Hydrogen 7 not only having gone through the BMW Group’s entire process of series development, but also being fully integrated in the conventional production process even as a hydrogen car: The new hydrogen model is built at BMW’s Dingolfing Plant parallel to the other models in the BMW 7, 6 and 5 Series, with the drive unit in BMW Hydrogen 7 coming like all BMW twelve-cylinders from the Company’s engine production plant in Munich.

Direct gasoline injection and hydrogen intake manifold supply

The hydrogen combustion engine is based on the gasoline power unit featured in the BMW 760i, offering the most advanced and sophisticated highlights in technology such as fully variable VALVETRONIC valve management and variable double-VANOS camshaft control. Further confirmation of the engineering skills of BMW’s engine development specialists is borne out by the modifications required for dual-mode drive, with fuel being supplied in the gasoline mode through direct injection and with a hydrogen supply pipe integrated in the engine’s intake system.

The key technology is the injection valves required to provide the appropriate fuel/air mixture, blowing exactly the right amount of hydrogen gas into the intake air within fractions of a second.

Burning up to ten times faster than conventional fuel, hydrogen offers a higher level of efficiency. To make use of this potential in full, the V12 power unit in BMW Hydrogen 7 requires particularly flexible engine management ensured ideally by VALVETRONIC and double-VANOS, where both the gas cycle and injection rhythm can be perfectly tailored to the specific features and characteristics of the hydrogen/air mixture.

Minimisation of nitric oxides

Under full load the power unit in BMW Hydrogen 7 runs under stochiometric conditions, meaning a complete balance of oxygen and hydrogen (lambda = 1). This mixture ratio also provides the highest level of performance and output on low emissions in the hydrogen mode.

With hydrogen, contrary to fossil fuel, not containing any carbon, the combustion of hydrogen generates neither hydrocarbons (HC) nor carbon monoxide (CO). If at all, minute traces of HC, CO, and CO2 emissions will be generated by the combustion of lubricant and by rinsing the activated carbon filter while running in the hydrogen mode.

The only relevant factor, therefore, is the emission of nitric oxides (NOX) generated above all at particularly high combustion temperatures. Highly flexible combustion management, however, allows an operating strategy able to largely control the formation of NOX. In practice, this means that the engine is run under part load with a high share of oxygen and, accordingly, a high lambda factor of more than 2.

In this case the temperatures in the combustion process are relatively low, keeping NOX emissions to an absolute minimum.

Such a lean burn mode can be maintained throughout a particularly wide range of operation in the engine control map. And since hydrogen offers particularly broad ignition limits and burns at a fast rate, only a small amount of fuel is required in the mixture to generate a high level of efficiency.

To boost engine output, the share of fuel in the fuel/air mixture is also increased in the hydrogen mode. This, in turn, means an increase in combustion temperatures under higher load. With the fuel/air mixture range creating the maximum amount of nitric oxide lying between lambda = 1 and lambda = 2, the engine management of BMW Hydrogen 7 cancels out this operating range with its negative effects on emission management without any reduction or change in torque.

NOX emissions are almost completely avoided under full load with a lambda factor of 1. To convert the minimum amounts of NOX still remaining under these operating conditions, all the engine needs is a regular three-way catalyst system, the specific composition of exhaust gases in a hydrogen combustion engine running under stochiometric conditions (lambda = 1) promoting the conversion of nitric oxides possibly contained in the exhaust emissions by way of the three-way catalyst. In practice, therefore, the drive unit featured in BMW Hydrogen 7 offers the same dynamic performance in the hydrogen mode as when running on gasoline, while emitting nothing but vapour in the process.