The BMW Hydrogen 7 is a limited production
hydrogen internal combustion engine vehicle
A hydrogen internal combustion engine vehicle (HICEV) is a type of hydrogen vehicle using an internal combustion engine. Hydrogen internal combustion engine vehicles are different from hydrogen fuel cell vehicles (which use electrochemical us ...
built from 2005-2007 by German
automobile
A car or automobile is a motor vehicle with Wheel, wheels. Most definitions of ''cars'' say that they run primarily on roads, Car seat, seat one to eight people, have four wheels, and mainly transport private transport#Personal transport, pe ...
manufacturer
BMW. The car is based on BMW’s traditional petrol-powered
BMW 7 Series (E65)
The fourth generation of the BMW 7 Series consists of the BMW E65 and BMW E66 luxury cars. The E65/E66 was produced from 2001 to 2008 and is often collectively referred to as the E65. The E65 replaced the E38 7 Series and was produced with petro ...
line of vehicles, and more specifically the 760Li. It uses the same 6-litre
V-12 motor as does the 760i and 760Li; however, it has been modified to also allow for the combustion of
hydrogen
Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, an ...
as well as petrol, making it a
bivalent Bivalent may refer to:
* Bivalent (chemistry), a molecule formed from two or more atoms bound together
*Bivalent (engine), an engine that can operate on two different types of fuel
*Bivalent (genetics), a pair of homologous chromosomes
*Bivalent log ...
engine. Unlike many other current hydrogen powered vehicles like those being produced by Hyundai,
Honda
is a Japanese public multinational conglomerate manufacturer of automobiles, motorcycles, and power equipment, headquartered in Minato, Tokyo, Japan.
Honda has been the world's largest motorcycle manufacturer since 1959, reaching a product ...
,
General Motors
The General Motors Company (GM) is an American Multinational corporation, multinational Automotive industry, automotive manufacturing company headquartered in Detroit, Michigan, United States. It is the largest automaker in the United States and ...
, and
Daimler AG
The Mercedes-Benz Group AG (previously named Daimler-Benz, DaimlerChrysler and Daimler) is a German multinational automotive corporation headquartered in Stuttgart, Baden-Württemberg, Germany. It is one of the world's leading car manufacture ...
which use
fuel cell
A fuel cell is an electrochemical cell that converts the chemical energy of a fuel (often hydrogen) and an oxidizing agent (often oxygen) into electricity through a pair of redox reactions. Fuel cells are different from most batteries in requ ...
technology and hydrogen to produce electricity to power the vehiclethe BMW Hydrogen 7 burns the hydrogen in an
internal combustion engine
An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combus ...
.
Production
![Motor Hydrogen 7](https://upload.wikimedia.org/wikipedia/commons/4/4a/Motor_Hydrogen_7.JPG)
BMW claims the Hydrogen 7 is the “world’s first production-ready hydrogen vehicle”; thus far, the Hydrogen 7 has been released to select high-profile lessees. Only 100 total vehicles were produced to put their technology to the test. BMW said it chose public figures such as politicians, media figures, businessmen and big names in the entertainment industry such as 2007
Academy Award
The Academy Awards, better known as the Oscars, are awards for artistic and technical merit for the American and international film industry. The awards are regarded by many as the most prestigious, significant awards in the entertainment ind ...
-winning director
Florian Henckel von Donnersmarck
Florian Maria Georg Christian Graf Henckel von Donnersmarck (; born 2 May 1973) is an Academy Award-winning German and Austrian film director. He is best known for writing and directing the 2006 dramatic thriller ''Das Leben der Anderen (The L ...
and the chairman of
Sixt
Sixt SE is an international mobility service provider with about 2,000 locations in more than 100 countries. Sixt SE acts as a parent and holding company of the Sixt Group, which is internationally active in the business areas of vehicle rental, ...
AG, Erich Sixt, because “they would be ideal ambassadors” for hydrogen fuel and could help spread awareness of the need for such technologies.
There is doubt over whether or not this technology will ever be put into larger production, even if hydrogen fuel technology reaches the point of economical and “green” feasibility, as well as to have the infrastructure required to put hydrogen vehicles in demand. The Hydrogen 7 uses more fuel than many trucks, consuming 13.9 L/100 km for petrol and 50 L/100 km for hydrogen. The following table shows the consumption (L/100 km) and fuel economy (mpg) for both Imperial and US gallons.
The difference in fuel consumption is largely due to the different
energy density
In physics, energy density is the amount of energy stored in a given system or region of space per unit volume. It is sometimes confused with energy per unit mass which is properly called specific energy or .
Often only the ''useful'' or extract ...
with gasoline (petrol) yielding 34.6
MJ/L and
liquid hydrogen
Liquid hydrogen (LH2 or LH2) is the liquid state of the element hydrogen. Hydrogen is found naturally in the molecular H2 form.
To exist as a liquid, H2 must be cooled below its critical point of 33 K. However, for it to be in a fully li ...
yielding 10.1
MJ/L. Based on these energy density figures, one would expect 47.6 L/100 km for hydrogen based on 13.9 L/100 km for gasoline (petrol); which is very close to the stated 50.0 L/100 km. Using hydrogen in an internal combustion engine as a source of energy is far less efficient than
fuel cell
A fuel cell is an electrochemical cell that converts the chemical energy of a fuel (often hydrogen) and an oxidizing agent (often oxygen) into electricity through a pair of redox reactions. Fuel cells are different from most batteries in requ ...
technologies; however, this is a system that is in production (albeit limited) now.
Nonetheless, hydrogen fuel (whether converted to energy in fuel cells or burned in an internal combustion engines) is not as green as it may seem; particularly so when you also consider that producing liquid hydrogen requires vast amounts of energy.
It will also be more expensive than its sister the 760Li (no retail price has been announced), which is BMW’s biggest and most expensive sedan, with a base price tag of over $118,000, thus further diminishing its widespread appeal. As of November, 2006, there were only five filling stations in the entire world that supported BMW’s filling technology, furthering the obstacles to making this car usable.
Use of hydrogen technology
![Wasserstoffeinfüllstutzen eines BMW](https://upload.wikimedia.org/wikipedia/commons/0/00/Wasserstoffeinf%C3%BCllstutzen_eines_BMW.jpg)
The BMW Hydrogen 7 burns hydrogen in an
internal combustion engine
An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combus ...
(ICE). When in hydrogen mode, high-pressure injectors, designed by HOERBIGER ValveTec GmbH, directly inject hydrogen gas into the cylinder combustion chamber with pressures of up to . The combustion technique is a combination of spark-ignition and diesel combustion systems using surface ignition, subsequently followed by a diffusion type of combustion. This combustion system matches the efficiency values of the currently best turbodiesel engines at a maximum of 42 percent. The car can also switch seamlessly between hydrogen and gasoline at the touch of a button on the steering wheel, and will do so automatically when one of the fuels is depleted.
The hydrogen fuel is stored in a large, nearly , bi-layered and highly insulated tank that stores the fuel as liquid rather than as compressed gas, which BMW says offers 75% more energy per volume as a liquid than compressed gas at 700 bars of pressure.
[Road Testing BMW's Hydrogen 7](_blank)
/ref> 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 thick wall of polystyrene Styrofoam
Styrofoam is a trademarked brand of closed-cell extruded polystyrene foam (XPS), commonly called "Blue Board", manufactured as foam continuous building insulation board used in walls, roofs, and foundations as thermal insulation and water barrie ...
.
To stay a liquid, hydrogen must be cooled and maintained at cryogenic
In physics, cryogenics is the production and behaviour of materials at very low temperatures.
The 13th IIR International Congress of Refrigeration (held in Washington DC in 1971) endorsed a universal definition of “cryogenics” and “cr ...
temperatures of, at warmest, . 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.
There have been some accusations of greenwash
Greenwashing (a compound word modeled on "whitewash"), also called "green sheen", is a form of advertising or marketing spin in which green PR and green marketing are deceptively used to persuade the public that an organization's products, aims ...
in reference to their BMW Hydrogen 7. Some critics claim that the emissions produced during hydrogen fuel
Hydrogen fuel refers to hydrogen which is burned as fuel with oxygen. It is zero-carbon, provided that it is created in a process that does not involve carbon. It can be used in fuel cells or internal combustion engines (see HICEV). Regarding hydr ...
production outweigh the reduction of tailpipe emissions, and that the Hydrogen 7 is a distraction from more immediate, practical solutions for car pollution. The BBC's Jorn Madslien
Jorn Madslien (Jørn Madslien) born 11 March 1967 is a journalist for BBC News Online and other BBC News outlets.
Madslien is features editor for the business and economics pages on the BBC News website. In addition he specialises on reporting i ...
questioned whether the Hydrogen 7 was "a truly green initiative or merely a cynical marketing ploy"
Specifications
The car is powered by a 6.0 litre V12 engine
A V12 engine is a twelve-cylinder piston engine where two banks of six cylinders are arranged in a V configuration around a common crankshaft. V12 engines are more common than V10 engines. However, they are less common than V8 engines.
The fi ...
capable of running on both premium gasoline and hydrogen fuel. It is rated at and of torque using either fuel. The car accelerates from stopped to in 9.5 seconds. The hydrogen fuel tank holds roughly of hydrogen, enough to travel . The gasoline fuel tank holds 73.8 litres equal to , enough to travel for a combined total of over at cruising speeds. The Hydrogen 7 gets about on hydrogen. In comparison, Honda's FCX Clarity
The Honda Clarity is a nameplate used by Honda on alternative fuel vehicles. It was initially used only on hydrogen fuel-cell electric vehicles such as the 2008 Honda FCX Clarity, but in 2017 the nameplate was expanded to include the battery-elec ...
gets about liquid hydrogen equivalent mileage. The curb weight
Vehicle weight is a measurement of wheeled motor vehicles; either an actual measured weight of the vehicle under defined conditions or a gross weight rating for its weight carrying capacity.
Curb or kerb weight
Curb weight (U.S. English) or kerb ...
of the Hydrogen 7 is roughly heavier than the 760Li, bringing it to about .
See also
* Bivalent (engine)
A bivalent engine is an engine that can use two different types of fuel. Examples are petroleum/CNG and petroleum/ LPG engines, which are widely available in the European passenger vehicle aftermarket.
Types Alcohol and Petroleum
Engines that ...
* List of hydrogen internal combustion engine vehicles
A hydrogen internal combustion engine vehicle (HICEV) is a vehicle powered by a hydrogen-fueled internal combustion engine. Some versions are hydrogen-gasoline hybrids.
1800s
* 1807 – Francois Isaac de Rivaz – the De Rivaz engine, the firs ...
Notes
External links
{{Commons category, BMW Hydrogen 7 (E66), BMW Hydrogen 7
BMW's hydrogen car: beauty or beast?
Article by GreenerMachine.com
Cars.com BMW Hydrogen 7 Prototype
Hydrogen 7
Hydrogen cars