Now those are some bodacious Tatas.

March 19, 2007 9:57 PM

For years, MDI has been developing a car that runs on compressed air. Last month, they signed an agreement with Tata Motors to produce the MiniCat - a zero-emissions vehicle that will travel up to 180 miles on $3 worth of fuel. See it in action here. (youtube)
posted by Afroblanco (45 comments total)

Totally not true. He even said the engine was constructed from this new metal with a totally made up fakey name: alyoumineeum. How bogus is that? Alyoumineeum. Sheesh.
posted by sourwookie at 10:08 PM on March 19, 2007

That shit is cool. And sourwookie, I'm sure there's something about alyoumineeum here.
posted by serazin at 10:14 PM on March 19, 2007

Anyone remember a toy made in the 1980s by Tomy, which was a VW Beetle that was powered by compressed air? It included a hand pump, you'd pump up the big tank inside the car, and it would go like a shot. Man, that was fun.
posted by Blazecock Pileon at 10:15 PM on March 19, 2007

MDI's air car has been "coming soon" for a decade. Every once in a while, they appear in the media, claiming that a launch is imminent. Bah.
posted by stereo at 10:16 PM on March 19, 2007

That's pretty cool, I'm just trying to figure out how many watts that "4 hour home recharger" would pull.

Man, though, aren't commenters on YouTube pathetic? Makes me proud to be a Metafilter member. Comment by comment;

1. Stoopid! Don't you know you have to use energy to compress the air first! (Well, duh...don't you know that the oil we burn now had the energy "put into it" millions of years ago, and isn't getting replaced? That's kinda why we need to look for alternatives.)
2. It's ugly! (Fair call)
3. See comment #1.
4. CO2 causing global warming is a lie!
5. Great, we can fuck over the arabs!

That's the point I kinda gave up reading...
posted by Jimbob at 10:22 PM on March 19, 2007

I don't get how a single tank of gas, running a compressor, is going to get this thing from Texas to New York like they claim in the video.
posted by zippy at 10:24 PM on March 19, 2007

And the entire article is misleading.

From the Press release:

Tata Motors, in keeping with its role as the leading company in India for automotive R&D, has signed an agreement, in yet another exciting engineering and development effort, with MDI of France for application in India of MDI’s path-breaking technology for engines powered by air.

It sounds like they are just doing some R&D together, no plans for the cars to be manufactured yet.
posted by zabuni at 10:30 PM on March 19, 2007

I don't get how a single tank of gas, running a compressor, is going to get this thing from Texas to New York like they claim in the video.

I think that was referring to the "hybrid" version, with both petrol and air.
posted by Jimbob at 10:33 PM on March 19, 2007

Recent AskMe thread about air cars.

When I used to work for public radio I remember screening a The World story on a prototype, the one thing I remember was that it WAS INCREDIBLY LOUD.

Blazecock (always such a pleasure to type), there were a bunch of totally cool toys that ran on compressed air, I had this awesome race car when I was, like, 13. It was really loud too, now that I think about it.
posted by nanojath at 10:36 PM on March 19, 2007

Someday someone's gonna put out a car I can buy on the used market for 5 grand a few years later and not starve on the maintenance schedule. The world will be a better place on that day.

Man, though, aren't commenters on YouTube pathetic? Makes me proud to be a Metafilter member.

Just so you can revel in the feeling a bit more without having to go anywhere...
posted by carsonb at 11:16 PM on March 19, 2007

Jimbob -

Glad to see someone else thought the same thing I did, and quickly.

While yammering about health improvements, and cost efficiency, and environmental concerns, not very many people stop to think that we need energy sources to compress that air or crack that hydrogen. And that, of course, leads us to the same problem that lead to these altfuel cars in the first place...
posted by Samizdata at 11:17 PM on March 19, 2007

someone's gonna put out a ^^clean car I can buy on the used market for 5 grand...
posted by carsonb at 11:18 PM on March 19, 2007

This is all just a bunch of hot compressed air.
posted by jimmythefish at 11:26 PM on March 19, 2007

What if the tanks ruptured in an accident? That'd be a hell of a blast. The amount of pressure needed to store so much energy must be pretty high.
posted by Mitrovarr at 11:30 PM on March 19, 2007

not very many people stop to think that we need energy sources to compress that air or crack that hydrogen

But the bright hope is that the energy sources we can use to do these things need not be fossil fuel based. Sure, we need energy to compress the air. Specifically, we need electricity. But we are reasonably good at generating electricity from solar, wind, geothermal, hell even nuclear, meaning that a compressed air car, while certainly requiring energy input, might not necessarily require fossil fuels.

Steven C. Den. Beste will likely show up shortly to remind us all that "renewable" energy sources don't have constant availability, yadda yadda - well, storing that energy "while the sun shines" in the compressed air tanks of cars doesn't sound unreasonable. We can plug them in and "rechage" them all during the day while we're at work in our offices.

Thats why I'm wondering how much energy that home compressor would use; little enough to be powered by some solar cells on my roof? At "$2" a recharge, I'm imagining it would require quite a bit more in reality, but I haven't done the sums.

My other question is; do you reckon this technology could be used on, say, a scooter / small motorbike?
posted by Jimbob at 11:36 PM on March 19, 2007

What if the tanks ruptured in an accident?

What if an LPG tank ruptured in an accident?
posted by Jimbob at 11:37 PM on March 19, 2007

What if the tanks ruptured in an accident?

It's mentioned in the video that they're made of carbon fiber, so they'll just split (rather than spray shrapnel everywhere). I wonder if an explosion could roll the car though?
posted by carsonb at 11:46 PM on March 19, 2007

What carsonb said. Nonetheless, I think it would still be scary as all hell if the did break.

Still, an interesting sounding idea, and as others have said, if a clean power source is used to compress the air, then it sounds awfully clean. Cool beans.
posted by HighTechUnderpants at 11:49 PM on March 19, 2007

carsonb: It's mentioned in the video that they're made of carbon fiber, so they'll just split (rather than spray shrapnel everywhere).

The shrapnel comes from the car. A large high-pressure tank of compressed air easily contains enough energy enough to blow it apart.
posted by Mitrovarr at 12:25 AM on March 20, 2007

Enough x 2? (editing mistake)
posted by Mitrovarr at 12:28 AM on March 20, 2007

A large high-pressure tank of compressed air easily contains enough energy to blow it apart.

I don't doubt the energy's there, but the implication in the video is that because of the way the tank would burst, the energy would not be narrowly directed. My assumption is that you have to direct the energy in the tank quite narrowly (ie via a small, fuel-injection-like spigot) to get it to move metal. I'm imagining the tank exploding like what happens when you open a canister of biscuits.
posted by carsonb at 12:47 AM on March 20, 2007

While neat, and an opportunity to move away from fossil fuels by using cleanly generated electricity (solar power is great, nuclear needs some serious advocacy in the US) it's vital to note that as of 2000 around 65% of the energy production in the United States was produced by the burning of fossil fuels.

So at this point, in this nation, we'd be adding a middleman to our fossil fuel consumption. That is to say, instead of burning it on a small scale individually we could centralize all our combustion to power plants. Which would probably be more harmful than beneficial.

Aluminum also takes a fair piece of electricity to produce and is rather expensive, as is carbon fiber.

So you know, sweet as it may be, and it sure could surely be awesomely great for everyone once we have a majority of renewable power sources... This car and cars like it are by no means a panacea to the problems we see today (at least not on their own).
posted by Matt Oneiros at 1:18 AM on March 20, 2007

Fossil fuel power plants are substantially more efficient than individual petrol or diesel motors; scale brings some definite benefits. However, you have to weigh that off against concentration of pollution and the efficiency losses when transmitting the power over wires, step-up/step-down transformers etc etc.

The whole basis of this sort of plan though is move most power generation centrally*, which basically will have to be nuclear fission plus some percentage of renewable, with an eye to nuclear fusion or some sort of other clean future tech taking over. Electricity continues to be generated, but we're stuck for a portable, high-density power store. Hydrogen is one possible, chemical batteries are another, compressed air is a possible third, giant flywheels are even possible, but they are all significantly less power dense than petrol and diesel, and all have technological implementation problems as a result of that. There simply isn't an easy answer yet. Lets hope we find one in the next 50 years, or we're going to be in real trouble.

*You can of course tie small local generation into that; solar, local wind generator etc, and charge your battery or whatever; but they're still fixed to a location, there's no high-density mobile power source that can be generated on the fly. Until we invent Mr Fusion running off garbage, of course.
posted by ArkhanJG at 2:02 AM on March 20, 2007

Oh, and don't forget coal is a fossil fuel; you can burn it in power stations but not cars, and it makes up 46% of total US generation. Still, dirty, dirty stuff. The amount of radioactive pollution caused by the burning of coal (releasing small amounts of uranium particles?) is greater than that you get from an equivalent nuclear station, let alone all the other pollutants.
posted by ArkhanJG at 2:07 AM on March 20, 2007

Matt-I don't think anyone is under the impression that this is some sort of perpetual motion machine. Of course it takes energy to run, but what makes this exciting is that if it's run from a clean, renewable energy source then it is a very green option.

You can't really say the same thing about fossil fuel based transportation-by definition, it's going to be releasing stuff into the atmosphere that we'd rather not put there. Of course we can (and should) be improving fuel efficiency in the meantime, but all that does is decrease the rate at which we're fouling our air. So that's why I (and others) are excited to see non-fossil fuel based transportation. Even if we're not yet at a point where it's favorable for people to have electric cars they are powering from the grid, this is great because it would royally suck if we got to that point and there were no vehicles ready to be sold to the average consumer. And for those who can afford to buy a car like this, or a Tesla, or a Tango (or whatever) and run it from solar cells atop their garage, well, I think that's exciting.

I guess what I'm saying is, of course no single technological innovation is going to solve the environmental problems caused by transportation. But this, in concert with developments in renewable and clean energy sources, is an interesting, promising development. IMHO.
posted by HighTechUnderpants at 2:26 AM on March 20, 2007

I'd like to be enthusiastic about this, but...

"Compressed air is one of the most expensive uses of energy in a manufacturing plant. About eight horsepower of electricity is used to generate one horsepower of compressed air. Calculating the cost of compressed air can help you justify improvements for energy efficiency." ^[i]
posted by maxwelton at 3:09 AM on March 20, 2007 [2 favorites has favorites]

The estimate they give in the video is two days worth of household electricity for a refill. So for me that comes out to about $3, which I believe is the same price they said it would cost to get the tanks filled at an adapted gas station.

For those complaining that you'd still be burning fossil fuel, remember that some places (like my province) receive 9x% of their energy from hydro power, and that we sell it to the states too. That alone could lead to a serious reduction in emissions, and if just a quarter of our taxis were to use it I could see it having a major impact on city smog.

If you concentrate your fossil fuel burning to power plants, then you can also benefit from better filter technology because you don't have to adapt it to a light-weight moving vehicle and a vehicle's maintenance schedule. They could stack the filters sky high and change them twice a day and you'd only see the impact on your electricity bill, divided by all the other electricity customers.

A lot of warehouse forklifts work on compressed air, so it's not like this is a new technology, only adapted.
posted by furtive at 4:01 AM on March 20, 2007

Oh man, Beyond Tomorrow. I cried myself to sleep for many years based on the broken promises of that stupid show.
posted by DU at 4:22 AM on March 20, 2007

or how about a proven technology using centrally produced energy:

trains! Choo Choo!
posted by geos at 5:28 AM on March 20, 2007

DU says Oh man, Beyond Tomorrow. I cried myself to sleep for many years based on the broken promises of that stupid show.

I used to watch that show when it was called Beyond 2000! *sniff*
posted by misskaz at 7:57 AM on March 20, 2007

Beyond 2000

Me too, but the music and breathless assurances that the future is JUST AROUND THE CORNER!!! are unmistakable. I think there might have been another permutation of the name in there too.
posted by DU at 7:58 AM on March 20, 2007

little enough to be powered by some solar cells on my roof?

It took more energy to create those solar cells than they will produce over their lifetime.

What if the tanks ruptured in an accident?

It's mentioned in the video that they're made of carbon fiber, so they'll just split (rather than spray shrapnel everywhere). I wonder if an explosion could roll the car though?

Carbon fiber composites don't split when they fail; they shatter (at least at the point of failure), throwing out lots of little carbon fiber segments a fraction of an inch long. A lot of the time, a "carbon fiber composites" also includes a wrap of Kevlar to contain the carbon fiber shrapnel in the event of failure. Kevlar is a worthy lightweight composite fiber in its own right, and is also the stuff of bulletproof vests.
posted by Doohickie at 8:36 AM on March 20, 2007

Not that I have any idea what the characteristics of these air engines are (torque, preferred rpm, etc), but it seems to me that an ideal proving ground for this tech (assuming it's half of what the inventors claim) would be the lawn care and landscaping industry. Imagine how much pollution (noise and air) you could get rid of by replacing all those fouling little two strokes with these things.
posted by crumbly at 8:50 AM on March 20, 2007

When it all boils down you know how I think it's going to come out? Small, high-efficiency, fuel-flexible diesels mounted in ultralight (probably thermally molded carbon fiber) frames. Nothing particularly new at all, just improved and integrated. They'll make the SUVs even bigger and meaner looking, with all these chrome spikes and pseudo-military accents, but they'll weigh a third as much.
posted by nanojath at 8:56 AM on March 20, 2007

The real value of this technology could lie in the rapidly expanding cities of the developing world. Given the level of toxic pollution from car emissions in such places, the non-smog aspect of these air vehicles could be a greater advantage that possible climate change benefits.
posted by sindark at 9:12 AM on March 20, 2007

JimBob: I think that was referring to the "hybrid" version, with both petrol and air.

I get that they're talking about a hybrid. The part I don't get is their claim that it will go nearly 2000 miles on a single tank of gas. Let's say the hybrid can go 100 miles just on compressed air, and further that it can hold 15 gallons of gas. Assuming the vehicle gets a fuel efficiency of 50mpg, that's a range of 850 miles (100 + 15 * 50).
posted by zippy at 10:14 AM on March 20, 2007

nanojath is close, but they'll do the diesel electric hybrid thing to generate torque for the trucks.

And the slogan will be "Tows Like A Train!".

Totally correct on the weight, spikes and military visual cues.
posted by dglynn at 10:16 AM on March 20, 2007

Dookickie, I was about to email you in private to ask why you're spreading misinformation, but I figured it might as well be out in public.

"Solar cells requiring more energy to make than they will generate" is a long debunked myth that you shouldn't be spreading. Over the 25-year lifespan of a modern solar cell, they generate 10x or greater energy than was required to manufacture them.

87% to 97% of the energy that PV systems generate won’t be plagued by pollution, greenhouse gases, and depletion of resources....

Energy "payback" time is 2 to 4 years, and 1 year for emerging technology. That's According to the National Renewable Energy Laboratory of the U.S. Department of Energy.

So I would thankyou to stop shouting your ignorance on Metafilter.
posted by Jimbob at 10:29 AM on March 20, 2007

I'm surprised the air-powered bike hasn't been mentioned yet.
posted by Kickstart70 at 1:11 PM on March 20, 2007

Did anyone watch past the first few minutes of the segment? The second inventor they show, the fellow in Australia, has built a motor that only ways 13 kilograms - a bit less than 30 pounds - that he's got powering a small vehicle that looks akin to a golf cart. The 5.7 litre engine in my old Chevy muscle car weighs something like 750 pounds, while a Honda 4-cylinder motor goes around 500 or so, for comparison.

Go forward to about 5:40 on the video and check it out. The presenter can hold the entire engine in both his hands easily. It looks like an ingenious design on a similar principle as the Wankel rotary engine that powers the Mazda RX-7 and RX-8, giving a very high displacement-to-output ratio.

As far as charging the car overnight or at some kind of filling station, remember that even with the built-in losses, using generated electricity is a lot more efficient than burning liquid fuel in millions of individual car engines. Having centralized compressor/storage at gas stations would be very efficient.

"About eight horsepower of electricity is used to generate one horsepower of compressed air."

So that gives an efficiency of 12.5%? The average car engine is only about 15% efficient, so if you've got a 300hp engine, you're burning the equivalent of 2000hp to get that output - that's 1.5 megawatts of power, to get some equivalency with electricity. And of course that's only counting the fuel in the engine; how much energy was used to refine the fuel, transport the fuel, and pump it into your tank... I think you'll find that compressor fueling stations for these cars would mean some pretty significant efficiency gains across the board.

"I get that they're talking about a hybrid. The part I don't get is their claim that it will go nearly 2000 miles on a single tank of gas. Let's say the hybrid can go 100 miles just on compressed air, and further that it can hold 15 gallons of gas. Assuming the vehicle gets a fuel efficiency of 50mpg, that's a range of 850 miles (100 + 15 * 50)."

My guess on that is that a small and light gas/petrol engine (like a 5HP Briggs & Stratton, maybe - or think about one of those small Honda portable generators) is there to run an on-board compressor to keep the air pressure up in the tanks. I have a hard time visualizing how one would create a dual-drive system (where both systems can drive the wheels directly) that wasn't extra complicated, although I suppose a 6-cylinder engine with 2 cylinders running on petrol fuel and the other 4 running on compressed air could be worked out... but that just seems like too much added weight to me, since you'd need separate intake, exhaust and cooling systems added on, plus designing to handle the heat differentials would be complex.

I think it would make a lot more sense to have a small, high-efficiency gas motor running a compressor directly; it would kick on when the tanks reached a pre-set low pressure, and click off when they reached a pre-set high. That part is proven technology, my art airbrush compressor does exactly that. It's simple and light.

The MDI car is pretty interesting, but it's unclear whether it will ever be produced; I think the other fella's tiny little rotary motor is way, way more interesting since its size should make it very easy to manufacture in large numbers at a very low expense.

I can't seem to find anything on the web about how the thing is holding up at that Melbourne wholesale warehouse though... be interesting to get some real world "in use" information.
posted by zoogleplex at 2:22 PM on March 20, 2007

It took more energy to create those solar cells than they will produce over their lifetime.

Cite?
posted by delmoi at 3:59 PM on March 20, 2007

Whoops. Motor that only WEIGHS 13 kg.

Type too fast, makey mistakey.
posted by zoogleplex at 4:46 PM on March 20, 2007

...surprised the air-powered bike hasn't been mentioned yet.

Or the air-power assisted motorcycle.
posted by Wash Jones at 7:24 PM on March 20, 2007

Sorry ... should be a big, fat, pimply NSFW tag on that last comment.
posted by Wash Jones at 7:29 PM on March 20, 2007

goes like a bat for the first 50 feet and drops rapidly after that
posted by altman at 3:07 AM on March 21, 2007