BMW at the 2005 NAIAS

Press Release

Hydrogen Combustion Engine on the Fast Lane

BMW Writes Motoring History ??????????????????????????????????????? Nine Records with the Hydrogen Combustion Engine

The BMW H2R Hydrogen World Record Car is being presented at the 2005 North American International Auto Show. In September 2004 BMW proved on the high-speed course of Miramas in France that hydrogen is able to power not only rockets and spaceships in achieving maximum performance: Nine records for hydrogen-drive cars with a combustion engine are clear proof the true capability of a hydrogen car.

???????????????????????????????????Nine records marking the starting point into the hydrogen age. BMW??????????????????????????????????????s hydrogen technology has come a long way. Now we must join forces with politicians and the energy industry in making our vision of sustained mobility reality????????????????????????????????, stated Professor Dr. Burkhard G??????????????????schel, Board Member of the BMW Group, during the record trials in Miramas.

At the high-speed course in Miramas, the BMW Group thus underlined its conviction that hydrogen is able to replace conventional fuels without requiring the driver to forego the dynamic performance of a modern car.

The data and performance figures of the H2R clearly confirm this superiority: Maximum output of the six-liter 12-cylinder engine is more than 210 kW/285 bhp, accelerating the prototype to 100 km/h in approximately 6 seconds and giving it a top speed of more than 300 km/h or 186 mph.

The hydrogen combustion engine is based on the gasoline engine of the BMW 760i, thus boasting the most advanced technologies such as fully variable VALVETRONIC valve control. The particular modifications involve the car??????????????????????????????????????s fuel injection adjusted to the specific features and characteristics of hydrogen. In the process H2R has benefited from the results already gained in series development of BMW??????????????????????????????????????s future hydrogen engine for the world??????????????????????????????????????s first premium sedan with dual-mode drive. During the production life of the current 7 Series BMW will be introducing a model able to run both on hydrogen and gasoline alike.

The H2R prototype set up the following records listed here according to times and speeds:

These records are still subject to homologation by the FIA Council, which is expected by the end of 2004.

BMW works drivers Alfred Hilger, J??????????????????rg Weidinger, and G??????????????????nther Weber took turns at the wheel of the record car.

These outstanding records not only prove the power and performance offered by the hydrogen car, but also underline the high degree of maturity BMW has achieved in the meantime in developing hydrogen drive. BMW??????????????????????????????????????s focus in the process is on the combustion engine which, given all its qualities, offers the most via option.

The H2R World Record Car developed in just 10 months.

The BMW H2R World Record Car was conceived, designed and developed by BMW??????????????????????????????????????s legendary subsidiary BMW Forschung und Technik GmbH. The name ???????????????????????????????????H2R???????????????????????????????? stands for ???????????????????????????????????Hydrogen Record Car???????????????????????????????? or ???????????????????????????????????Hydrogen Research Car????????????????????????????????.

???????????????????????????????????We had just 10 months to develop the car???????????????????????????????????, says J??????????????????rgen K??????????????????bler, the H2R Project Manager. But short periods and substantial demands of this kind are almost normal for BMW??????????????????????????????????????s creative engineers, who indeed benefited from three factors in this case: First, the components featured in BMW??????????????????????????????????????s future hydrogen production car have already reached a standard of maturity allowing their simple and straightforward use in the record car. Second, the development engineers, in designing the chassis, were able to use proven BMW suspension systems meeting the greatest demands and requirements. And third, far-reaching use of CAD technology helped to clearly focus and speed up the development process.

The engine: production 12-cylinder specially modified for hydrogen.

The ???????????????????????????????????heart???????????????????????????????? of H2R is based largely on BMW??????????????????????????????????????s top-of-the-range engine, the six-liter 12-cylinder. The use of hydrogen in driving the car is made possible by appropriate modification of engine management as well as the fuel/air mixture components.

The biggest difference in technical terms involves the integration of the hydrogen injection valves and the choice of materials in the combustion chamber: Contrary to the production engine with fuel injected directly into the combustion chambers, the injection valves on the hydrogen engine are fitted directly in the intake manifolds. For the record attempts the hydrogen combustion engine was laid out for single-mode operation running exclusively on hydrogen.

This clear focus allowed BMW??????????????????????????????????????s engineers to set up the engine specifically for hydrogen drive, for example by using valve sheet rings made of a special material. The reason is that hydrogen lacks the lubricating effect of a conventional gasoline/air mixture. And it is important to note in this context that such a change was already required upon the introduction of unleaded fuel with its reduced lubricating effect. Since then, production engines have been made of more resistant materials, anyway.

Higher efficiency with hydrogen.

The combustion properties of hydrogen are quite different from those of gasoline or diesel: Hydrogen burns faster at normal air pressure, but at a somewhat lower temperature than gasoline.

In the engine the higher combustion rate of a hydrogen/air mixture generates higher temperatures than in an engine running on gasoline. Accordingly, engine management of the BMW H2R World Record Cars has been modified to defer the ignition process until the piston reaches its top dead center, in this way ensuring maximum power and output.

With a gasoline/air mixture burning relatively slowly, by comparison, such a mixture must be ignited earlier as a function of increasing engine speeds, with maximum pressure being generated as the piston starts to move down. The higher combustion pressure of a hydrogen/air mixture also offers a significant advantage in practice, more power from the same energy ensuring a high level of efficiency.

As desirable as it is to use the ignition benefits of hydrogen within the engine, it is precisely this ease of ignition that calls for particular attention outside of the combustion chamber. So to avoid any misfiring, BMW??????????????????????????????????????s engineers have developed a special gas cycle and fuel injection strategy:

BMW??????????????????????????????????????s infinite VANOS camshaft control monitors and masterminds the share of residual gas according to specific requirements at each point in time. Before the hydrogen/air mixture is allowed to flow in, the combustion chamber is cooled by air guaranteeing that the mixture cannot ignite by itself in an uncontrolled process.

VALVETRONIC providing optimum conditions for hydrogen drive.

Using BMW??????????????????????????????????????s exclusive VALVETRONIC valve management featured as standard for controlling the valves on the 12-cylinder engine, BMW??????????????????????????????????????s engine specialists have an ideal ???????????????????????????????????tool???????????????????????????????? for masterminding this sophisticated gas charge cycle. For VALVETRONIC acts both on the duration of valve movement and on valve lift as such:

VALVETRONIC incorporates an intermediate lever between the camshaft and the two intake valves on each cylinder. The position of this lever relative to the camshaft may be varied infinitely by an additional eccentric shaft operated by an electric motor. Depending on the position of the eccentric shaft, the lever converts the humps on the cams into a larger or smaller movement of the valves, as required.

A further feature of VALVETRONIC is that it is based on BMW??????????????????????????????????????s infinite camshaft adjustment. This system called VANOS is an integral part of the VALVETRONIC concept. Incorporating a hydraulically controlled adjuster unit in the camshaft drive, VANOS is able to control the beginning and end of the valve opening times. Fully variable valve management of this kind serves to modify the gas charge cycle in the 12-cylinder engine perfectly to the needs and requirements of hydrogen drive.

Special injection valves for hydrogen drive.

The need to inject hydrogen into the intake manifold at the latest possible point makes great demands of the injection valves. Indeed, these valves are a new, trendsetting development by BMW: With gaseous hydrogen accounting for a greater volume per unit of energy than liquid gasoline, the injection valves are larger than conventional fuel valves. And at the same time they cover a far wider range, having to operate at a varying level of system pressure and with both very short and longer injection periods.

A fundamental objective in developing the valves was to inject exactly the right amount of hydrogen required into the intake manifold in a very short injection period at maximum engine speeds and under full load ??????????????????????????????????????? and this objective has been reached in full.

Clean mixture formation: fuel consumption down under part load, more power at full load.

Under full load the 12-cylinder engine operates with a fuel/air mixture of lambda = 1. This corresponds to the mixture also used in a modern diesel engine and which, in principle, develops maximum power in a combustion engine. Under part load ??????????????????????????????????????? another benefit offered by hydrogen ??????????????????????????????????????? the engine runs in a highly fuel-efficient lean burn mode with a surplus of air.

Since hydrogen combustion generates nitric oxides within a specific fuel/air mixture ???????????????????????????????????window???????????????????????????????? starting slightly above lambda = 1 and extending all the way to lambda > 2, this mixture window is cancelled here, as it is not required for running the engine:

Fast engine management in BMW??????????????????????????????????????s hydrogen engine is able to skip this window and thus avoid NOx emissions in the first place. So that ultimately H2R is just as powerful as a conventional car running on gasoline, but in practice emits nothing but vapor.

Safety systems.

The fuel system featured in the BMW H2R World Record Car is based on a proven concept carried over from series development. Fuel is filled into H2R at a mobile hydrogen filling station through a manual tank coupling. The vacuum-insulated, double-walled tank takes up more than 11 kilos or 24 lb of liquid hydrogen and is housed next to the driver??????????????????????????????????????s seat.

No less than three check valves ensure optimum safety: The operation valve on the tank itself opens up at a pressure of 4.5 bar. Two additional safety valves ensure that even leakage within the cryogenic shell does not have any dangerous consequences, the valves opening up as soon as pressure inside the tank exceeds 5 bar. This double-redundant safety system makes it impossible for the hydrogen tank to burst due to excess pressure.

Heat exchanger replacing the gasoline pump.

Gas pressure in the fuel supply system is generated by actively warming up the cryogenic liquid fuel in the tank then kept at an operating pressure of approximately 3 bar by tank pressure control. The coolant in the 12-cylinder engine subsequently warms up the hydrogen gas in a heat exchanger to ambient temperature.

Valve technology.

Further valves control gas pressure in the delivery lines to the engine: Cryogenic valves inside the tank monitor the extraction of hydrogen. Should any of the advance pipes develop a leak with supply pressure dropping below 0.4 bar, the extraction valves automatically close down, disconnecting the tank from its surroundings. The supply line may also be interrupted manually by a ball tap. To maintain optimum pressure on the injection valves ??????????????????????????????????????? which may vary as a function of driving conditions ??????????????????????????????????????? engine management reduces the pressure level in the supply line via a control valve to approximately 1.2 bar.

This comprehensive safety system featured in the H2R World Record Car is permanently monitored by telemetric control carried over from Formula 1: Four hydrogen sensors at neuralgic points ??????????????????????????????????????? for example in the tank area and around the tank coupling ??????????????????????????????????????? detect and report any leakage without delay.

Chassis and suspension.

Focusing on the load-bearing structure of the BMW H2R World Record Car, the development engineers at BMW Forschung und Technik GmbH used series components carried over from a high-performance BMW sports car: the aluminum spaceframe and the entire chassis. High-strength structural panels made of aluminum as an extra-light material resistant to corrosion fill up the spaces between the generously dimensioned extrusion-pressed profiles serving as the car??????????????????????????????????????s stable ???????????????????????????????????skeleton????????????????????????????????. This gives the driver a magnificent, absolutely direct feeling at the wheel free of any vibration.

Front wheel suspension is a double-arm spring strut type with rack-and-pinion steering, an aluminum track control arm, tiebars, and an anti-roll bar. The front axle subframe is a welded aluminum structure made of extrusion-pressed profiles and panels supporting all front axle components and bolted to the body at six points. The track control arm made of forged aluminum features two spherical joints ensuring precise wheel guidance at all times. Wheel guidance at the rear is provided by an integral four-arm axle, a multi-arm configuration complete with anti-roll bar patented by BMW.

Tires measuring 245/40x19 ensure optimum road contact and safety at all times.

Bodyshell: outer skin made of carbon-fiber.

BMW??????????????????????????????????????s designers were responsible for the unique body of the BMW H2R World Record Car. And indeed, in its proportions the body of the car is reminiscent both of classic BMW racing cars as well as speed record vehicles: H2R is 212.6 inches (5.40 meters) long and 78.7 inches (2.00 meters) wide, designed through and through for optimum aerodynamics.

An important factor contributing to the world speed record is the drag coefficient of just 0.21, with a frontal area of 19.9 square feet (1.85 square meters). A rear diffuser measuring 7.87 inches or 20 centimeters in length prevents air swirl behind the car possibly slowing it down.

The side profiles as well as the sheer length of the car serve additionally to maintain stable driving characteristics even at maximum speed. As on a Formula 1 racing car, the outer skin is made of carbon-fiber-reinforced plastic, thus offering the optimum combination of supreme stiffness and low weight: Overall weight of the H2R with a full tank and the driver in position is just 3,440 lb or 1,560 kg.