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Steam Hybrid Car from BMW
RMX writes "BMW is unveiling its turbosteamer hybrid engine, which uses the excess heat in the exhaust system and reclaims 80% of it by powering a steam engine that assists the gas engine. Overall, this gives a 15% more efficient engine; and significant additional performance (power and torque) with practically no downside. "This project resolves the apparent contradiction between consumption and emission reductions on one hand, and performance and agility on the other," commented Professor Burkhard Göschel. Are steam engines the future of environmental-friendly hybrid vehicles?"
BMW has the ability to make Hydrogen-powered production cars, it is a shame that they have not caught on yet.
Current fuels will eventually go the way of the steam engine, or wait, maybe not the steam.
Interesting site: http://www.bmwworld.com/hydrogen/
He who knows best knows how little he knows. - Thomas Jefferson
German online news site Spiegel Online has more details on this:
Heat plant in the car. It uses a high temperature (up to 550 Celsius) circuit using water and a low temperature one using ethanol (alcohol) (operating at 150 Celsius). Both are closed systems.
The pictures accompanying the article suggest the system interfaces with the relatively large radiator already in the front of the car. It is not going to produce nearly as much steam as an engine that would power the entire car, and this steam engine doesn't need a heat source either.
Don't forget that most turbocharged engines will give up some fuel efficiency as compared to a naturally aspirated engine of the same displacement even when operating under light loads. This is because in order to handle (without blowing head gaskets or detonation) the increased charge density provided by forced induction, they must use a lower static compression ratio. Lower compression ratio generally equals less efficient combustion.
This is why Saab developed this.
"Prefiero morir de pie que vivir siempre arrodillado!"
" I think you are confusing fuel and engine form. Diesel is just a fuel, it doesn't dictate the engine type."
Oh yes it does! Just try putting diesel fuel into your Otto Cycle automobile!
The Diesel Cycle is inherently different from the Otto Cycle in that there are no sparkplugs. As opposed to an external ignition source, diesel engines use nothing but the compression in the cylinder to ignite the air-fuel mixture. Overgenerallizing a little, diesel engines operate entirely on what you would call "knock."
I could go on about temperature vs. entropy comparisons between the Diesel and Otto cycles, but your eyes would glaze over.
For the same compression ratio, the Otto Cycle is more efficient than the Diesel Cycle. However, when engineering comes into play, you can have much, much greater compression ratios with a Diesel engine than an Otto engine. The source of ignition in a Diesel Engine is the pressure in the cylinder, and the pressure is uniform throughout the chamber, ensuring uniform combustion and uniform expansion of the cylinder. You can get away with building cylinders, say, 1 m in diameter. With the Otto Cycle, because you need an ignition source (sparkplugs), combustion in the chamber will be non-uniform and there will be more energy lost because of it, so F-1 and GPX cars use many, many cylinders that are very long but very slender. Only a fool would use an Otto Cycle engine to power a locomotive, let alone a ship.
"So... there's no reason you couldn't make a highly efficient diesel external combustion (probably steam) engine."
No. Diesel means internal combustion. If you want external combustion, you build a steam turbine (far fewer moving parts), and they don't care what you burn. There's no reason to burn something as expensive as refined diesel fuel. Modern steamships burn whatever it is the refineries can't sell to anybody else.
You could try a gas turbine, but, again, diesel fuel isn't designed for that; it will ignite when you don't want it to, and not ignite when you need it to. Go with kerosene.
"So... there's no reason you couldn't make a highly efficient diesel external combustion (probably steam) engine."
Not a mechanical engineer, are we?
"If the water runs out,"
Then you take it back to the dealer. The water isn't supposed to come out, you put your superheated steam through the preheater, getting it back down to saturation before you put it back into the boiler again. You should no less run out of water than you would run out of motor oil or transmission fluid (with similar Very Bad Things happening to your engine if you do).
> The only thing hydrogen is good for is to reduce emissions from the
> vehicles themselves, but you only end up pushing the pollution to
> power generating stations, which we'll need a lot more of if the
> 'hydrogen economy' takes off.
Except that you're missing a critical piece here: since hydrogen extraction facilities are very large and stationary (something most cars are not), they can use fuels that would simply not be an option for the cars themselves, such as wind, solar, wave or nuclear power. And even if you do keep producing hydrogen by burning fossil fuels, because of the size and relatively low number of production facilities you have the economic luxury of investing in technologies that burn fossil fuels more efficiently and transform waste into more benign forms than would be feasible in the cars themselves.
You can't take heat from the catalytic converter because that heat is required to catalyze the gasses. That's why emissions suck for the first 5 or so minutes that you run your car - the catalyst is cold and not doing its job. That's also why urban areas use MTBE and other oxygenates in fuel in the winter time - so that the mal effects of the cold catalyst are mitigted.