Adelard of Bath wrote: I watched it in college...hee hee
A mechanical engineering student in college, watching a show for people much younger than myself? Cool.
I think my favourite one was the one on "the desert" I think....that must be what it was about cuz he kept saying "Death...Valley..." over and over and I almost died laughing and no one could figure me out.
Another engineer on this forum :blink:. Hell, we should all get together and start our own motor company. We can design a millenium version of the tercel 4wd.
Adelard of Bath wrote: Only if you let me design a nice gas turbine engine for it! woo hoo!
FOR SURE!! I absolutely love the idea of turbine engines in cars!! I've thought lots about this concept too. I have no idea why this never took off. I think Chrysler messed around with the concept in the 60's (and actually had running cars), but dropped it for some reason. I think that some of the materials technology was too expensive and advanced at the time, but with the use of turbine engines in most aircraft these days, the technology is well established and understood.
Points to consider:
- Only one main moving part (the compressor and turbine) - spins in one direction, so momentum is not lost (unlike the constant change of velocity of pistons in a convential automobile engine).
- More power per unit weight/size of engine
- At least twice the efficiency of a conventional automobile engine
- Can run it off hydrogen, thus producing zero emissions
- Would need a pretty fancy constantly variable transmission (as the throttle response of a turbine engine is very poor compared to a piston engine)
- Did you know that they actually used a turbine engine in racing for a while? The car using the turbine was super kick ass, but the regulating authority kept changing the rules regarding the intake size of the turbine, thus limiting the car to eventual failure.
- The technology of a gas turbine engine is obviously far beyond the 100 year old design of a piston engine. It's too bad auto manufacturers are not revisiting it.
Oh yeah, and I'll design all the electrical/electronic systems, including an EMS (engine management system) for the gas turbine.
I'd think that with turbines in cars, your major hurdles would be:
emmissions
noise
high temp operation
super high rpm
which also turns into a reliability issue
And I bet there is a whole building of lawyers sitting around somewhere, just WAITING for someone to put a turbine in a car and have it go horribly wrong....
hhe
You know, I am always surprised that NOBODY realises that you could engineer the turbine to put all of its output into ROTATIONAL power, everyone imagines this jet-nozzle sticking out the back of the car, frying the people behind them...
But, I know they use them in navy ships etc, and sometimes in portable generators, don't they use them in train engines? In that case, they run generators and suddenly you don't have a problem of a transmission anymore...but rather a super high torque electric motor
Hmmm I can see it now...a hybrid tercel 4wd using a tiny gas turbine instead of an IC engine....interesting.
Make it run off diesel available at any station, and you have a winner
hehehe
As I recall, the fuel can be run past the bearings for cooling and lubrication, so you don't need oil, and THAT is why jet fuel is the same as kerosene and it is oily
Actually in my kerosene heater in the garage I run diesel...i dont have any jet fuel laying around.
Too bad for 4wdrules who started this post with the Previa question....
lets make a turbine powered Previa how about that! No coolant as far as I know, so therefore overheating problem solved. course underhood temps would be.....crazy
oh and then somebody can shorten the previa wheelbase and add 4wd so I can have a sweet offroader
Adelard of Bath wrote:
But, I know they use them in navy ships etc, and sometimes in portable generators, don't they use them in train engines? In that case, they run generators and suddenly you don't have a problem of a transmission anymore...but rather a super high torque electric motor
I had thought about the possiblities of not having a transmission too actually. Just use the turbine shaft to drive a generator. Electric current can be controlled and routed to electric motors for the front and rear axles (or all wheels individually). This would again reduce the weight of the car.
They are actually experimenting with hydrogen gas turbine engines (big ones) in the US...for power generation I think...kerosene works too, but roads would reek like jet fumes at an airport.
Haha sorry for hijacking your thread tercel4wdrules. I think your previa questions were answered fairly well, but feel free to ask more.
While those ideas are well based... There is a lot of fine-tuning to your ideas that is needed.
The problems with the 60's turbines were; heat management, "turbo-lag", very high RPMs, and noise.
Now.. The idea with electric motors for each wheel, you would need the motors mounted towards the center of the line relative to the wheel- like in an independant suspension. Why? Keep the weight sprung. Unsprung weight is not exactly your best friend. It creates more rotational mass causing decreased braking as well as more weight not being "sprung" causing a rougher ride.
Exhaust routing is an issue. You don't want to catch trees aflame, but you don't want to melt peoples fairings either. You could of course come up with a heat dispersal system, which decreases exhaust flow efficiency. You could point it from many nozzles down. Sure, it melts ice and snow on the road, but creates lift which is your enemy at speed. Many nozzles up? Want to catch your garage door on fire? Or the trees down the way? Or the electrical cables in the tunnel you are passing thru?
Want to spin a generator? Well, its a good idea, but you'll need a clutching system. Remember, a turbine doesn't start and suddenly have 100 horses. You start it and it puts out 9, then over the course of maybe 1-3 seconds is raised to about 50 horses at idle in the case of a turbine the size of the one in Jay Leno's jet-turbine powered motorcycle. You get it going and its power could quite rapidly go to 260 horses. So the clutch would have to variably engage over more horsies, but that means a "warm-up" period before you could drive too far. Sure, you could have a 200 lb capacitor bank to let you drive 3 miles while it warms up, but that is expensive and inefficient. So it looks like you'd need a variable transmission for this as well, low gears for early on, higher gears for later on. Obviously hehe. Well, turbines are thirsty buggers. I dunno the range on Leno's bike, nor the fuel capacity, but to get an idea... An M1-A1 Abrahms tank drains a 120 gallon tank in about 120 miles. It uses a turbine. Now, you compare that to a diesel engines roughly 120 gallons to 60-100 miles, that is a nice improvement. But also consider the drivetrain development cost something like a billion dollars on that bugger.
Where was I going with this hehehe....
A turbine can run off almost anything flammable. Put butane in it, it'll go. Put olive oil in it, it'll run. Put gas, diesel, kerosene, or peanut oil in it and it'll rev. That kind of flexibility in a car is a major major asset.
A turbine is very very lightweight. In the world of models, a 4.5 lb turbine can put out 23 lbs of thrust.
In a car, you would need to concoct a lubrication system. Lets face it, big bearing changes every 15,000 miles doesn't sound too fun. Good thing? There are only maybe 3 bearings in a very basic turbine. Its power routing that makes it more difficult, like tranny and driveshaft lube. I dunno how they do it on the helocopters and boats.
The idea of a turbine in a car as a means of power is smart, but you'd need to compensate for the lagginess of a turbine. You think a big turbo-charger lags? A turbine engine is worse. Again, they put one of the turbines in a super-sport motor bike and it is tolerable, but consider that it only weighs about 550 lbs. If you could come up with a system that stored power in a lithium ion or nickel cadmium battery cell for takeoff, you might be set. Just enough to get you up to maybe 15 mph. By that point the turbo should be making sufficient power to provide acceleration. Terrifying thing about it is that the gearing you would have to use to get it moving in low RPM's would get it going very fast. We are talking a turbine spinning 50,000 RPM's and up.. You get a first gear that get you moving from 25,000 RPMs, and your turbine redlines at 75,000 RPM, that is 50,000 RPM's of play. Now, a turbo built for this kind of application would have a much more narrow band, closer to 20,000 RPM, but that is still significant. So that makes for 2 scarey componants;
A turbine produces more power the faster it goes (until self-destruction)
A turbine spins at rediculousy high RPM's and has a very large RPM range.
What does this combo make for? Well, to give you an idea....
A test driver on Leno's jet bike ran it full-open down a moderatly long runway. The driver backed off at 225 or so MPH in 3rd gear.. He backed off because he was terrified to go any faster. If you've ridden a motorcycle at a mere 100 MPH, you understand this I'm sure. Now for the scarey part- he was only 7/8 thru the RPM band for 3rd gear and had 4th gear yet to shift into.
Can you say- GOVERNERS and MARKET TO THE GERMAN PEOPLE!
RIP 10-07- 1984 Toyota Tercel SR5 4wd Wagen 6 speed
RIP 04-05- 1986 Toyota Tercel SR5 4wd Wagen 6 speed
Thanks for the input! Humans have overcome many more difficult challenges than these. I'm sure it can be done. An electromagnetic clutch could be used between the turbine and generator (same sort of clutch as is used to turn AC on). It would take way more money to develop this thing than any of us will ever have...but I still think it is a really cool idea.
Hey I have been wanting to read about Leno and his collection, but I guess I always forget to find a link online or anything....I know he writes (or used to) articles for popular mechanics or something and those are fun to read; know anyplace like that online, or leno saying "here are my cars" blah blah blah
that guy is pretty cool, he has a sweet love for wrenching and is down to earth about cars...dont really like his show though
I used to work at a place and we had a drivetrain for cars that was run off a microtubine to generate electricity and a carbon fiber fly wheel to store electricity. It was pretty trick. Sounded cool. Do a google search for Rosen Motors if you want more info. They may have something out there still about it. It was hot technology at the time.
Well, you could always use a magnetic spacial coupling. It consists of alternate-pole magnets spaced in a fan config and points two of these together. One rotates, it transfers torque to the other with no resistance between. If you could have a combination of permanant rare-earth-metal magnets and electromagnets, you could form a linkage that would allow gradual decrease of "slip" allowed, transferring more power to the generator side and creating enough looseness to allow the turbine to start up. The rem magnets could be used to allow a slippage of maybe 1000 turns of the turbine to 1 turn of the generator. As power generates, the electromagnets slowly are increased in magnet pull, causing less and less slip, untill you are in a 1:1 or maybe 1:2 generator:turbine slippage ratio. Of course, this means a warm-up period of maybe a minute, with full power going towards the electromagnets for the first while, untill the turbine is spinning proficiently to take full load, then allowing power to be put thru to motors and accessories.
Remember.. electric motors have maximum torque at literally just above zero RPM's. Perfect for dragging.
You could adapt that coupling to a clutch on the powered side, allowing the turbine to "idle" at maybe half-way up its power band, or whatever is necessary to get the vehicle moving. The magnetic coupling again allowing a lag-time or slippage to take place. In this situation though, you'd have to have a centrifugal clutch linked generation system on the turbine side of the equation. Just imagine the powering possibilities though... You look at an alternator, it provides peak power around maybe 2400 RPM right? You get a turbine producing 100 horsies at 24,000 RPM, gear that 24,000 down to 2400 for the generator or alternator.... Imagine the wattage you could pump thru these babies.
If any people with mechanical knowledge are interested in the concept.... Maybe you could get it started? I mean.. If we could develop half of the system and maybe test it to scale... Look what we could get started.
But then again... The cost of turbine engines is very high. Heck, a model sized one putting 32 lbs of thrust out costs roughly $3800.
Again, market to the German people hehehe.... These cars could be hyper-speedsters and thus to some people would justify the projection of maybe a $75,000 pricetag for the equivalent of a Passat VR6 with this drive system.. Of course, after the necessary frame bolsterings, it'd run maybe $85,000. But hey, if ou could make it sporty, fun to drive, economical, fast, responsive, and safe, a lot of better-off people would buy it. The base model from Ruf of Germany (they modify Porsche's into the best supercars in the world.. These things run circles around Ferrari's and Lambo's speed-wise and are right alongside with the other marks) is $90,000. And its barely even modified off the Boxter S. lol.
RIP 10-07- 1984 Toyota Tercel SR5 4wd Wagen 6 speed
RIP 04-05- 1986 Toyota Tercel SR5 4wd Wagen 6 speed
Ingenious idea. Did they ever figure out power-holding over long periods? That truly is a potentially revolutionizing concept.
Please.. Explain what issues you/they ran into.
Sooo... This was done roughly 10 years ago.. They need to restart the program if it was unsuccessful. I'm sure it could go a lot further with modern technologies.
RIP 10-07- 1984 Toyota Tercel SR5 4wd Wagen 6 speed
RIP 04-05- 1986 Toyota Tercel SR5 4wd Wagen 6 speed
Financial feasability? I think that is why most seemingly good projects don't go anywhere....those of us here might be into it, but...
I dunno, its all getting too deep for me! turbines sure are fun, but IC is definetely tried and true...when I was in college a number of years ago, we were all theorising on the awesomeness of hybrids, and i see it is FINALLY catching on....I say there is hardly a better way to go, although I would rather see it go in this direction:
Dedicated electrics for drive, and a TINY engine running at its one specific speed, running a generator, only when needed. Once you set the speed and the load on an engine, efficiency = good
but at least Ford is popping a hybrid engine (technology purchased from toyota, like seven out of who knows how many patents) into that little suv. And I heard that Toyota plans to have them available in their whole lineup by 2006. that's moving in the right direction! cuz if I could get a hybrid tercel 4wd...those forest trails better watch out! ooh I could switch the engine to "off" and run in silent mode, like "hunt for red october" which would make the whole camping experience that much sweeter, and I wouldn't have to put up with chevy z71s and their huge pipes
Humans have overcome many more difficult challenges than these. I'm sure it can be done. An electromagnetic clutch could be used between the turbine and generator (same sort of clutch as is used to turn AC on). It would take way more money to develop this thing than any of us will ever have...but I still think it is a really cool idea. 