Hydrogen Mazda RX-8

Hydrogen Mazda RX-8
Mazda Motor Corporation today announced that it has delivered one dual-fueled RX-8 Hydrogen RE vehicle, which runs on either gasoline or hydrogen, to the Japan Automobile Research Institute. The Mazda RX-8 Hydrogen RE has a rotary engine with a dual-fuel system that allows the driver to select either gasoline or hydrogen fuel with the flick of a switch. Cool.
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alchomaialchomai - 3/14/2007 12:23:57 PM
0 Boost
nice work. congratulations. I think there's nuff said bout this issue, isn't it?

so, what now?


5MTenthus5MTenthus - 3/14/2007 12:52:41 PM
+1 Boost
Running on hydrogen, it is half as powerful as it would be if it were running on gasoline. Needless to say, still in development.


Will_Will_ - 3/14/2007 12:57:12 PM
0 Boost
I like the concept of hydrogen-powered cars being able to run on either gas or hydrogen however, burning hydrogen just seems pointless altogether anyway.


cdokecdoke - 3/14/2007 2:47:07 PM
+1 Boost
I would say there will be some additional problems due to the combination of hydrogen and th rotary engine. I have yet to figure out why they always use the term "rotary engine" evey rotary engine is technically a "Wankel Engine" and they have been around, as I recall, since the 1950's. The reason that you don't see them in cars is that they have massive sealing probles, not only between fuel stages throught the multiple apexes of the convex triangualr piston, as it were, but also between the piston housing and the crankshaft: resulting in fuel encroachment.

Replacing hydrocarbons [literally carbon chains whith hydroge attached] with teh much smaller molecual of hydrogen itself will exacerbate this problem.


cdokecdoke - 3/14/2007 4:25:03 PM
+2 Boost
My knowledge on this subject is due to my engineering education, ans has more to with the history of the engines development. I will be the first to admit that I know litte about Mazdas particular engine.

I do know that in general the ingingement of fluid across to verteces of the convex triangle is generally considered insignificant from a fundamental standpoint simply because it can sort of be circulated out. It does however decrease the efficiency of the engine, by reducing the compression efficiency: it leaks. The biggest problem is that if you take the rotation chamber and look at it from the sidem: it looks like a box, and what happens is that along the face of the convex triangular I'll call it an impellar, impinges into teh crashaft space. This is not however a static process, it is dynamic. Sections once occupied by fuel become exposed to the crankshaft as the interior gear set [the one in the middle of the impellar, rotates oblongly about the crankshaft. This causes primarily the fuel to impinge in that rotating space which is exposed to the crankshaft. This further decreases efficiency, in addition creating a a potentially dangerous situation. Such a thing is less of an issue in a reciprocating pictons engine simply because the general place for leaks is along the axis of the chamber and has some capacity to do work. In addition, in the RPE the seals are exposed to two directional loads. In the Wankel engine, the loading of the seals is continually variable.

Viscosity of a fluid is generally a function of molecule size. That is a bit on an oversimplification, since for example there is pressure dependence, and in oil there is acutally a local mimima of the viscosity as a function of that pressure at the bubble point and as pressure is increased, viscosity increases slightly. That just models ability to flow abstractly. Let me explain it a different way. Hydrogen is significantly smaller molecule than hydrocarbons, and as such can fit through smaller tolerances. Places that were not leaks with hydrocarbons become leaks with hydrogen, in particular when you try to pressurize it.


cdokecdoke - 3/14/2007 4:26:19 PM
+1 Boost
My was that poorly written.


5MTenthus5MTenthus - 3/14/2007 7:14:03 PM
+1 Boost
They just put a (the first) hydrogen filling station here in Irvine.


VinnyPVinnyP - 3/14/2007 9:16:30 PM
+1 Boost
Has anyone watched that film "Who killed the Electric Car" they have some good points as to why Hydrogen is inferior to that of the Electric car, or in just any case, how Hydrogen is not a good alternative.

"Hydrogen is a much tougher alternative fuel than any other alternative out there"

1) Fuel Cell cars using Hydrogen uses 3 to 4 times more energy than a car using batteries.
2) Current Hydrogen Car costs $1 million dollars
3) Not enough room for hydrogen fuel. Need an enormous amount of hydrogen storage within a car to get decent mileage out of it.
4) Hydrogen Fuel Infrastructure, meaning more pumps like the ones built in Irvine as said above.
5) Hydrogen Fuel is expensive. Costs 2 to 3 times more than gasoline.

I recommend everyone watch this movie if you get the chance, because it gives some good points that makes you think. The best alternative that is coming, is PLUG-IN hybrids.

Even a Toyota exec. for the Toyota Hydrogen vehicles Bill Reinert said the hydrogen car is many years away, and is inferior to electric cars.

Bill Reinert "The Worst question is when will this vehicle be available." Thats what we should be asking for these hydrogen cars being built shown as concepts right now.


VinnyPVinnyP - 3/14/2007 9:18:34 PM
+1 Boost
And to reply to this Mazda car, just imagine how much it will cost to have a car like this, that can take 2 different fuels. Its a good idea do, but probably crazy expensive.


chewychewy - 3/15/2007 7:43:59 PM
+1 Boost
Silly.

1. Burning hydrogen.
2. Rotary engine.
3. Just for hype.


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