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JesseJames
Mar 5, 2004, 06:36 PM
I'm really liking what's coming out of the Mazda motorstables.

http://www.new-cars.com/news/040105-mazda-rx8-hydrogen-rotary-engine.html

wdlove
Mar 5, 2004, 07:10 PM
I'm really liking what's coming out of the Mazda motorstables.

http://www.new-cars.com/news/040105-mazda-rx8-hydrogen-rotary-engine.html

It does look cool, but when are they going to make to make a "green" car for the older adult. Also for the vertically challenged!

Dippo
Mar 5, 2004, 08:19 PM
I'm really liking what's coming out of the Mazda motorstables.

http://www.new-cars.com/news/040105-mazda-rx8-hydrogen-rotary-engine.html


I don't think it looks that great, looks like every other Mazda out there.

Frohickey
Mar 5, 2004, 08:22 PM
Now THIS would be a car, environmentally friendly or not, that I would buy and use.

Imagine. Rotary powered for quick revs and quick response on the pedal.
Ability to use gasoline for those times when you are not near a hydrogen station.
And with hydrogen, you get the additional power from intercooling.

WOW!!!

Whats the 0-60 and quartermile speed/time of this car when its running on H2?

I think a 2 rotor engine is like a 6 cylinder engine, with the weight and volume of a 4 cylinder engine. And its not that difficult to add another rotor to the package.

Hmm... how about if you both have gasoline and H2 available? Wouldn't that be like having a nitrous system?!!! :D

agreenster
Mar 5, 2004, 10:03 PM
I don't think it looks that great, looks like every other Mazda out there.

Yes, but it runs on hydrogen, stupid. (unlike every other car out there.)

Next time, READ the article and dont just look at the pictures before posting a silly comment like that....sheesh.

lind0834
Mar 5, 2004, 10:25 PM
Very nice.. I'm still waiting for the Fuel Cell VW Golf.. but that's just me.

zimv20
Mar 5, 2004, 11:23 PM
It does look cool, but when are they going to make to make a "green" car for the older adult. Also for the vertically challenged!

i don't know your height, but you might want to try a VW New Beetle. my 6'6" friend was pleasantly surprised. you can get one w/ a TDi engine (diesel). mine gets 40/55 mpg. i've gotten 60+ on the highway at times. good acceleration, too.

rainman::|:|
Mar 5, 2004, 11:49 PM
It does look cool, but when are they going to make to make a "green" car for the older adult. Also for the vertically challenged!

the new Prius ought to do. Lexus features, Toyota styling, hybrid system, and not bad price-wise. Basically, imagine a normal car (tho really high-tech) that does not burn gas unless it goes above 30mph. All of the city driving you do below that, all of the time sitting at stoplights... no gas used. This thing has a completely silent idle, which is cool :) (unless you're using your air conditioner, as the engine or batteries need to power that). If you do mostly highway driving, this won't save you *that* much gas; but if you do any amount of city driving, it's a boon.

Plus it's not ugly and cliché like the beetle.

paul

zimv20
Mar 5, 2004, 11:56 PM
Plus it's not ugly and cliché like the beetle.


guns at dawn

Sayhey
Mar 5, 2004, 11:57 PM
Excuse the ignorance from a non-engineer, but this is still a internal combustion engine not fuel cell technology, right? I'm assuming that hydrogen burns a lot cleaner than gasoline in such an engine, but does it still put out emissions that are harmful to the environment? If so why go this route?

MrMacMan
Mar 6, 2004, 12:10 AM
Ah gotta love the rotarty engine...

Quite unique in its design... + hydrogen powerd...


Very very nice indeed.

zimv20
Mar 6, 2004, 12:39 AM
this is still a internal combustion engine not fuel cell technology, right? I'm assuming that hydrogen burns a lot cleaner than gasoline in such an engine, but does it still put out emissions that are harmful to the environment? If so why go this route?

if it's the same kind of rotary-wankel as was used in the rx-7, then it is indeed internal combustion. iirc, hydrogen engines produce NOx, but at lower concentrations than gasoline engines.

wdlove
Mar 6, 2004, 11:49 AM
i don't know your height, but you might want to try a VW New Beetle. my 6'6" friend was pleasantly surprised. you can get one w/ a TDi engine (diesel). mine gets 40/55 mpg. i've gotten 60+ on the highway at times. good acceleration, too.

I'm 6' 8" I haven't been in one of the new VW Beetles. But did drive one of the older one's a '65 model and a '75 model. For the price they couldn't be beat. They were great around town and good in the snow. I had plenty of head room. The problem was the my knee was almost up against the dash board. Most of my height is in my legs. Amazingly even in something like a Cadillac, I could use more leg room.

zimv20
Mar 6, 2004, 01:15 PM
I'm 6' 8" I haven't been in one of the new VW Beetles.

if you get a chance, try sitting in a New Beetle. i'd be interested to know if you find it comfortable. dunno if he still drives it, but i know Shaq bought one a few years ago.

pooky
Mar 6, 2004, 02:43 PM
Excuse the ignorance from a non-engineer, but this is still a internal combustion engine not fuel cell technology, right? I'm assuming that hydrogen burns a lot cleaner than gasoline in such an engine, but does it still put out emissions that are harmful to the environment? If so why go this route?

It is indeed a hydrogen combustion engine, which is certainly atypical as most hydrogen systems seem to be leaning toward fuel cells. Pure hydrogen combustion doesn't produce any organic or nitrogenous pollutants, though it does producea greenhouse gas (water): H2 + O2 -> H2O. It's not clear what the widespread production of water vapor would do, but it is certainly much more desireable than carbon dioxide.

Now of course, that's in an ideal system. I don't know the particulars of combusting hydrogen in an engine, so there may be other pollutants produced. Someone mentioned NOx...

rainman::|:|
Mar 6, 2004, 02:53 PM
It is indeed a hydrogen combustion engine, which is certainly atypical as most hydrogen systems seem to be leaning toward fuel cells. Pure hydrogen combustion doesn't produce any organic or nitrogenous pollutants, though it does producea greenhouse gas (water): H2 + O2 -> H2O. It's not clear what the widespread production of water vapor would do, but it is certainly much more desireable than carbon dioxide.

Now of course, that's in an ideal system. I don't know the particulars of combusting hydrogen in an engine, so there may be other pollutants produced. Someone mentioned NOx...

The problem is hydrogen production, to produce serious quantity pollutes as much, or more according to some people, pollution as an internal combustion does. So the push for hydrogen cars is counterproductive, until better methods of hydrogen production are found... which could be a ways off...

paul

zimv20
Mar 6, 2004, 03:25 PM
H2O.[...]Now of course, that's in an ideal system. I don't know the particulars of combusting hydrogen in an engine, so there may be other pollutants produced. Someone mentioned NOx...

as you imply, the implementation would be short of ideal. iirc, the NOx is produced because of the aspiration involving outside air.

cr2sh
Mar 6, 2004, 06:45 PM
Its a shame its just a concept car. I'd love to wn one of these.

Mazda.com has a PDF on this vehicle:

http://www.mazdausa.com/MusaWeb/NA_Autoshow/downloads/hydrogen_re.pdf

Backtothemac
Mar 6, 2004, 07:56 PM
Yes, but it runs on hydrogen, stupid. (unlike every other car out there.)

Next time, READ the article and dont just look at the pictures before posting a silly comment like that....sheesh.

Um, actually, you should re-read it. It is a dual mode motor. It will run on Gasoline, or hydrogen.

Frohickey
Mar 8, 2004, 01:56 PM
Excuse the ignorance from a non-engineer, but this is still a internal combustion engine not fuel cell technology, right? I'm assuming that hydrogen burns a lot cleaner than gasoline in such an engine, but does it still put out emissions that are harmful to the environment? If so why go this route?

H2 combines with O2 to make steam/water as the combustion byproduct. The high temperatures in the engine, along with the O2 and N2 in the air makes the NOx compounds that are considered pollutants.

Now, if we can only make H2 from H2O using nothing but solar power (ie plants with chlorophyll), we'd be set. Genetically modified, anyone?

Frohickey
Mar 8, 2004, 01:58 PM
The problem is hydrogen production, to produce serious quantity pollutes as much, or more according to some people, pollution as an internal combustion does. So the push for hydrogen cars is counterproductive, until better methods of hydrogen production are found... which could be a ways off...

paul

Same with fuel cells using hydrogen.

TANSTAAFL... err... TANSTAFE :D

wdlove
Mar 10, 2004, 08:56 PM
The demand accelerates for Toyota hybrid


By Royal Ford, Globe Staff, 3/10/2004


Claire Boudreau, a self-described environmentalist, knew from the moment the concept was introduced that she wanted a hybrid gasoline/electric automobile -- once the kinks had been worked out of the technology.

So, the Ayer woman marched into Acton Toyota on Oct. 1, as soon as the lighter, more efficient, 2004 Prius hit dealerships, convinced she was near the head of the line.

At best, she was near the end of a national line that formed even before the car appeared in a showroom. And it is a line that continues to grow -- one so long that those waiting for 2004 models may have to be patient until the 2005 models roll off the assembly line. It has left frustrated buyers and dealers across the country struggling to keep up with the public's hunger for a car whose popularity has outrun its production.

"Demand has gone through the roof," said Toyota spokesman Wade Hoyt.

http://www.boston.com/news/nation/articles/2004/03/10/the_demand_accelerates_for_toyota_hybrid/

JamesDPS
Mar 10, 2004, 09:07 PM
Anyone know how power using H2 compares to petroleum fuel? I like the direction cars are going in now: clean without being an obviously different car, but the RX8 is already too slow as it is... I was excited before they came out originally, but that faded very quickly. If this isn't as powerful as the normal model, what's the point of trying to make it look like a sports car?

Personally I'm stoked about the Lexus RX400h (a hybrid that combines a 3.2L V6 with two electric motors to produce torque and hp of a 4L v8, hence the name, while getting something like 35 mpg and producing incredibly low emissions). Also, I heard a rumor somewhere that Mazda might bring back the RX7, which would be awesome. I'm a fan of the rotary engine, and the old RX7s are sweet (twin turbo does 0-60 in 5.2, not too shabby), but all the new cars are way too slow (I like the look of the Mazda 6, for example, but they top out at something like 180hp or something... WEAK SAUCE!)

So for now I think perfect combo is a big comfy hybrid (like the lexus) and a real sports car that does it the old fashioned way for your weekends :D

Frohickey
Mar 10, 2004, 10:04 PM
The demand accelerates for Toyota hybrid

It has left frustrated buyers and dealers across the country struggling to keep up with the public's hunger for a car whose popularity has outrun its production.

"Demand has gone through the roof," said Toyota spokesman Wade Hoyt.

http://www.boston.com/news/nation/articles/2004/03/10/the_demand_accelerates_for_toyota_hybrid/

Great. So, with demand outpacing supply, prices for the Toyota hybrid would be high. I guess I keep on waiting.

Frohickey
Mar 10, 2004, 10:49 PM
Anyone know how power using H2 compares to petroleum fuel? I like the direction cars are going in now: clean without being an obviously different car, but the RX8 is already too slow as it is... I was excited before they came out originally, but that faded very quickly. If this isn't as powerful as the normal model, what's the point of trying to make it look like a sports car?


Hydrogen Economy (http://maemail.ucsd.edu/~mae118a/2003_Presentations/AchievingHydrogenEconomy_DistributionUtilization_HoffmanGroup.pdf)

-Compressed H2 has less energy per unit volume than gasoline (octane)
-1kg of H2 by weight has about the same amount of energy as 1 gallon of gasoline.


Chapter 4 (http://physics.weber.edu/schroeder/eee/chapter4.pdf)
Consider again reaction 4.1, which involves only hydrogen and oxygen atoms. When one mole of hydrogen molecules (two grams) combines with half a mole of oxygen molecules (16 grams) to form one mole of water molecules (18 grams), the energy given o? turns out to be 242,000 joules, assuming that the water comes out as a gas rather than as a liquid. (If the water comes out as a liquid, then the total energy released is greater: 286,000 joules.) Since there are 500 moles of hydrogen gas in a kilogram, this means that burning a kilogram of hydrogen gas releases 500
times as much energy, or 121 million joules (again, assuming that the water comes out as a gas, as is usually the case in a combustion process).
2 grams of H2 is 242 kilojoule. 1 kilogram of H2 is 500*242 kilojoule, or 121 megajoules of energy.
1 gallon of Gasoline has 121 megajoules of energy.
1 cubic foot is 7.481 gallons.
Gasoline is 46.81 lbs per cubic foot.
2.2046lbs to a kilogram.
Liquid H2 is 4.23 lb. per cubic foot.

To make the math easier, lets say a typical car has a 14.962 gallon fuel tank of gasoline (thats 2 cubic feet). (93.62 lbs of gasoline)
That means for the same energy, you want 14.962 kilograms of H2.
14.962kg*2.2046lb/kg = 32.9862lbs
32.9862lbs/4.23lb/ft^3 = 7.800 cubic feet
Okay...
93.62 lbs of gasoline == 32.9862 lbs of liquid H2
14.962 gallons of gasoline == 58.336 gallons of liquid H2

Fuel injectors are usually rated as cubic feet per minute (CFM), so to keep the horsepower the same, you need to inject 3.9 times more liquid H2 than gasoline to get the same OOOMPH. Do they make bigger higher flow injectors, sure. But you would also need a fuel tank thats almost 4 times as big!!! I think you are going to be driving a SUV-sized car, for that much liquid H2! :eek:

agreenster
Mar 11, 2004, 08:10 AM
Um, actually, you should re-read it. It is a dual mode motor. It will run on Gasoline, or hydrogen.

Yes yes yes I know.

But my comment was aimed at the person who said, "It looks like every other Mazda out there" when in fact, its nothing like every other Mazda out there. I think they just looked at the picture and made a comment.

wPod
Mar 11, 2004, 11:07 AM
yes yes, we can all calculate the power in H2 but. . . has anyone paid attention to history? what was the last device to use H2 on a large scale, can you say 'Hindenburg' H2 is a bit more volitale than gasoline. just what we need, a bunch of dumb drivers with a bomb of H2 on the back of their cars. a little fender bender punctures the tank. . . then you can say goodbye to like the entire block around the car (ok maybe not that bad) but all you making the calcultions, you must have had a chem class recently (or in your memory) and when i was in chem class, my proff always blew up hydrogen baloons. . . like little balloons would wake up everyone in a huge lecture hall. . . i couldnt imagine the effects of a larege pressurized tank surrounded by a car full of shrapnel. maybe everyone will become safer drivers. . . or at least all the non-safe drivers would be blown sky high. . . and thats not even considering the large tankers of H2 diving around filling up gas stations. . . or gas stations themselves. . . you get a hole in a gasoline tank and you clean up a bit and patch the hole. . . you get a hole in your h2 tank and well there will be people cleaning up and re-building for quite a while.


just a thought.

Frohickey
Mar 11, 2004, 12:30 PM
yes yes, we can all calculate the power in H2 but. . . has anyone paid attention to history? what was the last device to use H2 on a large scale, can you say 'Hindenburg' H2 is a bit more volitale than gasoline. just what we need, a bunch of dumb drivers with a bomb of H2 on the back of their cars. a little fender bender punctures the tank. . . then you can say goodbye to like the entire block around the car (ok maybe not that bad) but all you making the calcultions, you must have had a chem class recently (or in your memory) and when i was in chem class, my proff always blew up hydrogen baloons. . . like little balloons would wake up everyone in a huge lecture hall. . . i couldnt imagine the effects of a larege pressurized tank surrounded by a car full of shrapnel. maybe everyone will become safer drivers. . . or at least all the non-safe drivers would be blown sky high. . . and thats not even considering the large tankers of H2 diving around filling up gas stations. . . or gas stations themselves. . . you get a hole in a gasoline tank and you clean up a bit and patch the hole. . . you get a hole in your h2 tank and well there will be people cleaning up and re-building for quite a while.


just a thought.

Did your chemistry professor also make a fuel-air bomb from a thimble of gasoline atomized for efficient burn? "Oh, the humanity!" :p

What we need is Mr. Fusion.