I want
An Electric Car.
No, really. Not a Volt, or a hybrid, but a pure electric or turbine electric, because, lets get serious here, the efficiency of an electric drivetrain at putting the rubber to the road is unequalled by any mechanical system that can be made. Shit, diesel electric is how they use locomotives to pull 24,000 ton trains.
Using the correct electronics, you can accelerate faster with electric motors than anything, because electrics can be used to carefully monitor and put power to the ground right at the very limit of tire slippage, and four very small wheel mounted motors can do more than just move the vehicle around, they can regeneratively brake to save energy, they can change speeds readily in cornering, etc.
I don’t give a shit for fuel economy; I want to have a small quiet car that’s ass kicking fast and can outrun and outhandle just about anything, and soon enough Electrics are going to be the way to do it.
On the other hand, there’s the volt. The $300,000 answer to a question that nobody asked.
24 comments Og | Uncategorized
I’m itching for a Tesla Model S. Gotta have a back seat.
It seems that the government asked, “Would anyone like a quarter million dollars per unit to produce a piece of crap”?
And GM answered, “Yes please”!
I want one that can carry 6 adult passengers and their luggage and tow 8,000 pounds.
… and fly.
The idea of an electric motor at each wheel is VERY close to what Tucker was originally wanting to do with the Tucker Torpedo. Back then, electric motors were not as advanced, and he wanted to use a hydraulic motor at each wheel.
Design it. Collect materials
We kin build it at my house(workshop).
All I ask is a few bucks for welding gas.
Say the word.
I have access to robotic welding equipment. I don’t have the time or inclination. I want to buy it, not build it. I won’t live long enough.
*sigh* Why is this always so hard? Is it just that people want it so badly?
Down where the quantums live, all chemistry is molecules exchanging electrons with one another. If you look up something called the “electromotive series” you will find a list that tells you how eager the molecules are to engage in that sport. Pick any two; the difference between the numbers in the last column is the energy available.
If the reaction is weak and peaceful enough, it may be possible to capture the electrons and force them to do work in a circuit before reaching their molecular destiny. If you do that, you have a battery.
But if the electromotive difference is big enough, you can’t do that. The electrons go directly to their destination, and the energy comes out as heat — in which case it’s called combustion.
In both cases exactly the same thing is happening: electrons are being swapped around. It follows that batteries are wimpy by definition — you can’t make a battery out of any pair that yields enough energy to be useful, because the energy comes out as heat. You’re better off calling one “fuel” and the other “oxidizer”, and using that combination in a heat engine.
There does exist the fuel cell, in which the electrons from an energetic reaction are captured before they get where they’re going and forced to traverse a circuit, doing work. The problem there is that you have to split the electrons off from the fuel before they start reacting; to do that requires strong electric fields in a so-called catalyst, and there are only a few catalysts that work at all — and those only work with the simplest molecule, hydrogen. In everything else, the catalyst isn’t strong enough to pull the electrons out, and the fuel cell doesn’t work. Catalysts are extremely expensive and virtually impossible to fabricate, and hydrogen is so small that the concept of “tank” is empty: there are only various grades of filters for it.
Back at the turn of the Twentieth Century people were building electric cars with a range of sixty to a hundred miles, because that’s what’s possible with batteries. Now, at the turn of the Twenty-First Century, people are building what’s possible with batteries, which is electric cars with a range of sixty to a hundred miles.
Until and unless you find a way to store and/or generate electricity by other than chemical means, batteries are what you have, and sixty to a hundred miles is the range you’ll get: end, period, full stop, end chapter, end book.
Regards,
Ric
The trick is to do it the way Og suggested, i.e., the way EMD did for locomotives — constant speed diesel alternator charging batteries, dynamic braking, etc.
Indeed. I want the batteries to act as temporary storage at most, while a turbine provides the juice. I was born at night, but not last night.
Seems to me I recall that the serious hobbiests in the jet-engined RC field have access to some serious small gas turbines. Maybe one of them could be used to spin a generator.
FWIW back about 8 or 10 years in one of those odd little specialized industy magazine I read about a project for the US military that was on the order of a 100 pound diesel that spun a 1KW generator. Only saw the one article, never saw another thing about it.
Back in the heyday of the GM Impact, I saw where Burt Rutan opined that GM oughta remove a couple of batteries and drop a gas turbine generator in there, just big enough to cover base loads.
The real problem, though, is that gas turbines aren’t as efficient as good piston engines; they are used in planes because they are light for their power output and are marvelously reliable, but they are thirsty. A Boeing 747’s four engines produce more power than the engine room of a supertanker, at a tiny fraction of the weight, but the tanker probably burns less fuel per kilowatt.
So while a turbine-electric hybrid would be a *fantastic* race car or sports car, it would have trouble with CAFE and emissions regs, I think.
I’ve got a well-used ’90 Suburban 1500 that blew the engine at 175k miles. Before I got talked into replacing the old busted one with a new longblock, I took a long hard look at Kohler two cylinder diesel power units, a hefty little generator and a stout high voltage, high amp DC motor. Would have been simple enough to bolt into the cavern Chevy calls the engine bay of a ‘Burb. Controllers can be bought off the shelf. 1 gal/hr fuel consumption at 70mph sounds like 70mpg to me.
A friend of mine when I lived in St. Louis had a VW Rabbit that he converted to electric after the motor blew. I think he used an electric motor out of a forklift and his battery pack was 6 8 volt fork lift batteries. He only used it to go to work the store and home. Since he worked for One of the forklift repair companies in St. Louis he got most of his stuff for it for free.
Hitler, at least, made the VW affordable.
“The real problem, though, is that gas turbines aren’t as efficient as good piston engines;”
I’m not sure what you’re smoking, but you should stop, and bury it. it’s damaging your brain.
Rankin/Brayton turbines run at two or three times the efficiency of anything with pistons, and there is a lot of talk now about breaking the 60% efficiency barrier. Piston engines at peak can only do about 30% and that’s pushing it hard. And yes, I’m talking turbines, not jets. Jets provide thrust, turbines provide angular momentum.
GM made turbine buses, years back, but they had horrible driveability issues because they used the turbine to directly power the vehicle- which meant changing speeds of the turbine constantly. At a set speed, turbines are most efficient and using them to run a generator (at a single, most efficient speed) to charge batteries is a good idea. Which is why Jag did it.
http://www.popularmechanics.com/cars/alternative-fuel/electric/jaguar-hybrid-micro-turbine-engineering
They’re using Bladon jets, which is a company to watch.
http://www.bladonjets.com/technology/gas-turbines/
Og,
“GM made turbine buses, years back, but they had horrible driveability issues because they used the turbine to directly power the vehicle- which meant changing speeds of the turbine constantly.”
Don’t forget this one.
Using the straight mechanical output from a turbine is just turning money into noise, which only works if you’re the government. Running at constant speed to turn a generator makes more sense.
Huh, Og. That is interesting. I had thought turbines were one of the lesser efficient engines.
Turbines and turbine generators are remarkably efficient, because at a single speed, they can be really remarkably efficient, and charging batteries would take place at a single speed. So far everyone but Jag has used the mechanical output of the turbine to turn the vehicles wheels, at which turbines suck donkey dick. use them to charge a battery- and only enough battery to act as a buffer during accel and decel is required- and this is a much better solution all around. Frankly, I’m pissed nobody is using it.
Indeed, tam, the Chryslers were monumental flops for a variety of reasons.
I remember going through most of this same comment thread in my head during engineering school 15 years ago.
1. Turbine (on whatever fuel) makes DC
2. Excess DC is stored in buffer
3. Buffer supplies DC to motors on each wheel
It still seems simple. If it wasn’t for item 2.
Batteries are still about the only buffer layer option and their weight, charge/discharge rates and cycle ranges still aren’t good enough. Their weight is especially craptastic in a passenger vehicle, especially when you’re already carrying 20 gal of liquid energy to get started.
High speed flywheels were bounced around back then (maybe now too, I’ve been in computers since) but their failure characteristics are “spectacular.” Low speed flywheels don’t have the needed charge/discharge rates.
I heard rumors about capacitor storage research that had me rubbing my hands together. Those things can take and release charge fast but couldn’t hold enough at a time. I haven’t heard anything since.
This, still, sucks. I’d line up behind Og for my copy if it existed.
All y’all are forgetting that AMC did the battery/electric thing in a Concord DL back in the mid-70’s. It also had a diesel genset in a light trailer that you hooked up just when the 40 miles battery range wasn’t going to be enough. Problem was, the trailer rig was an option, and it was to cost almost as much as the car.
Never got past the prototype stage.
“Rankin/Brayton turbines run at two or three times the efficiency of anything with pistons, and there is a lot of talk now about breaking the 60% efficiency barrier.”
The only turbines I’ve seen coming anywhere close to 60% are in combined-cycle applications, in which you use the exhaust heat of the gas turbine (or piston engine, for that matter) as input heat for a secondary steam turbine. Combined cycle is great for large stationary installations, but AFAIK has never been successfully applied in motor vehicles.
Ultimately, the efficiency of any combustion engine of whatever design is limited by the delta between working temp and exhaust temp. You can make any design more efficient by extracting more energy from the exhaust (combined cycle, turbine in the exhaust pipe, MHD, thermocouples, heat exchangers) or by raising combustion temps. Single-pass gas turbines tend to have worse exhaust temps than piston designs, and in cars combustion temps are limited more by NOx emissions regs than by materials limitations, I don’t see turbines as being able to exceed optimized-for-baseload piston engines in vehicle applications. Direct-injection piston engines working at their optimal BMEP are as efficient as any road-able gas turbine that I’m aware of. I’d love to be proven wrong, though; I’ve wanted a turbine powered car since I was a kid watching Knight Rider.
“AFAIK has never been successfully applied in motor vehicles.”
So…. you didn’t like, read the actual words that I wrote, yes?
“Direct-injection piston engines working at their optimal BMEP are as efficient as any road-able gas turbine that I’m aware of”
Ah, no. You didn’t.
Try actually reading the words that I wrote. The “Roadable” turbines you know about are of course not the ones I’m referring to, which you would know, if you, say, read the post.
And NO direct injection engine ever aproaches the efficiency of turbines, even at constant speed.
aczarnowski:
carbon nano-tube capacitors. Researchers were saying about 7 years to bring it to market (any time now, IIRC). They figured it would take that long to figure out how to manufacture it. Cell phone size would charge in seconds, car batt size in a couple minutes, or less. Can’t remember who, now (big name).