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First hydrogen vehicles introduced in Crash Recovery System

Technology Update July 2009

July 1th, 2009
 

Moditech Rescue Solutions is continuously monitoring the automotive market for new developments that could affect emergency response to vehicle accidents or car fires.

Alternative fuels and alternative propulsion are among the biggest challenges responders will be facing in the near future.

 

The Crash Recovery System is already prepared to show vehicles with alternative propulsion and therefore the decision was made to introduce the first two hydrogen-powered vehicles to the CRS database, well knowing that these vehicles are not really produced in series.

‘Emergency Responders are highly interested in emerging new technologies and are trying to prepare themselves for the new challenges.’ says Jan Mooij of Moditech Rescue Solutions. ''We are trying to support their efforts with the introduction of the first hydrogen-powered vehicles to our database. These sample vehicles can be used to assist training and to showcase how the future will look like. Besides, both vehicles are ‘on the road’ in Europe and North America and can of course also be involved in accidents.'' 

 

The problem of all current vehicles equipped with alternative propulsion is, that the deactivation procedures are not standardized and differ from vehicle to vehicle. Hence vehicle information is very important to make sure the vehicle can be disabled quickly and extrication techniques can be adapted to the vehicle.

 

Below some technical information about the vehicles that have been introduced:

 

BMW HYDROGEN 7

 

The BMW Hydrogen 7 is a limited production hydrogen vehicle built by German automobile manufacturer BMW. The car is based on BMW’s traditional gasoline powered 7-series line of vehicles, and more specifically the 760Li, however, it has been modified to also allow for the combustion of hydrogen as well as gasoline, making it a bivalent engine. Unlike many other current hydrogen powered vehicles the BMW directly ignites the hydrogen in its internal combustion engine.

 
The hydrogen fuel is stored in a large (110 liters) highly insulated tank that stores the fuel as liquid rather than as compressed gas. The hydrogen tank’s insulation is under high vacuum in order to keep heat transfer to the hydrogen to a bare minimum, and is purportedly equivalent to a 17 m thick wall of polystyrene Styrofoam.

To stay a liquid, hydrogen must be super-cooled and maintained at cryogenic temperatures of, at warmest, -253 °C. When not using fuel, the Hydrogen 7’s hydrogen tank starts to warm and the hydrogen starts to vaporize. Once the tank’s internal pressure reaches 87 PSi, at roughly 17 hours of non-use, the tank will safely vent the building pressure. Over 10-12 days, it will completely lose the contents of the tank because of this.

Beside the safety feuatres of the conventional BMW 7 series, the Hydrogen 7 contains a couple of features to make the use of hydrogen as safe as possible, including a gas warning system and pressure relief devices with a ventpoint on the roof of the vehicle.

 

 

 

MERCEDES-BENZ A-CLASS FCELL

 

The Mercedes-Benz A-Class F-CELL is based upon an extended version of the first Mercedes-Benz A-Class chassis. It has a Proton Exchange Membrane (PEM) hydrogen fuel cell that powers the vehicle and provides 72kW output power. An electric motor, rated at 65kW drives the front wheels. Unlike the BMW Hydrogen 7, there are two onboard hydrogen fuel tanks pressurized at 345 bar (similar to the pressurized tanks used to store CNG in vehicles nowadays).

Onboard, the A-Class F-CELL has regenerative braking that provides charging capability when applying the brakes and the vehicle has an energy storage system that works in conjunction with the fuel cell using nickel metal hydride (NiMh) batteries. The entire fuel cell power system for the F-CELL A-Class fits under the vehicle driving compartment and no interior space is lost from the original petrol (gasoline) version.