EPA Invents Battery-Less Hybrid System

I have often wondered if the compressed-air engine could be utilized in a IC-air hybrid as an alternative to battery electric. One possibility would be a pluggable air option with a 20 mi. air only range (a PHCFV?). It seems like this is a more practical application of compressed air storage than trying to get a 100 mi. + CFV (compressed fluid vehicle) range.

EPA Invents Battery-Less Hybrid System
Hybrid drivetrain uses compressed fluid instead of electricity. To be tested on UPS trucks.

http://money.cnn.com/2005/12/21/Autos/hydraulic_hybrids/index.htm?section=money_latest

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Called hydraulic hybrid technology, the system uses energy stored up during braking to help propel a vehicle during acceleration. The energy is stored in pressurized hydraulic fluid, the same sort of fluid used in brake lines and for power steering.

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In the EPA's hydraulic hybrid system, braking pressure is used to power pumps that compress hydraulic fluid. This stores energy in the same way you would if you squeezed a spring with your hands. When needed, the pressure is released and the expanding hydraulic fluid is used to power gears that help turn the vehicle's wheels. The EPA began working on the system about 10 years ago, said Oge, under a Clinton administration program to research clean energy technology.

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There is a major advantage to the EPA's new system and one major disadvantage, the agency said. The advantage is its simplicity and relatively low cost. The system would cost an estimated $600 to install on a mass-production basis, the agency estimates, compared to $3,000 to $6,000 for an electric hybrid system. The disadvantage is the system's weight, the EPA says. According to a 2004 EPA report, a hydraulic hybrid SUV would weigh about 190 pounds more than a conventional SUV. That means the EPA's system is most applicable to trucks where the added weight would make a smaller overall difference, the agency said.

The added weight of the system is similar to the weight of an electric hybrid system, although the EPA itself cites weight as a disadvantage.

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how it works.

It was my understanding that liquids are considered incompressible. That's why hydraulic systems can work so well; the fluid doesn't compress but transmits power, rather than absorbing it through compression as a gas would.

The article says "The energy is stored in pressurized hydraulic fluid..." which is a well-known and widely used method. However, it says later that "braking pressure is used to power pumps that compress hydraulic fluid."

Any clarifications?

if one of those hoses breaks! There could be some serious burn injuries from the hot hydraulic fluid.

is included in the system?

reason, when you compress air, you get heat.

this type thing might make sense in a commercial
vehicle that makes a lot of stops, like a post office truck.
I think the idea is to store the energy as compressed air,
in an insulated 'can', powered by a hyraulic cylinder.

Compressed air for vehicles, is usually a scam,
otherwise, it would be done more.

Both liquids and gases are considered fluid states.

Solids are also compressible. The volume of a condensed state of matter changes with pressure according to a more or less constant value known as the bulk modulus. The bulk modulus of most materials is very much a function of their composition. This is different than is the case for gases, where generalized "ideal" states can be visualized as a first approximation. (In fact gases vary considerably under certain circumstances from "ideal behavior" and many state functions for gases have been used, depending on the accuracy required and the conditions applicable, all of which contain constants that are functions of composition. These composition dependent functions are analogous to a "bulk modulus" for gases.)

As a condensed state of matter, liquids and solids resist compression more than gases.

That said, condensed states require considerably more work to compress than do gases. I have a lot of trouble visualizing how this thing might work. In essence though, the behavior of fluids under compression is essentially what underlies the operation of all hydraulic devices. My problem has to do with the mechanical conversion of pressure energy of a condensed state (liquid) to rotary motion like that in wheels. I'm sure though that there are mechanical engineers who understand such things far better than I do.

There is a point for all substances, known as the critical point, at which gases and liquids are indistinguishable. Many modern power plants operate above the critical point of water, which is only present at temperatures above 373C and pressures 22,000 kPa, 220 atmospheres. Thus some "steam" turbines are not really "steam" turbines. They are supercritical water devices. Some critical fluids are accessible at temperatures close to room temperature. Supercritical carbon dioxide, which already enjoys wide technological use, with many other such uses contemplated (including dry cleaning), is accessible at 31C and 73 atmospheres.

I think compressed air - which is already widely used to store (or distribute) energy for powering tools like impact wrenches in auto repair shops and air brakes on trucks - has many properties that recommend it as an energy storage device. One possible technological side product for the wide use of compressed air in large plants is the production of water - albeit in small amounts and, through the use of gas separation membranes, the removal of carbon dioxide. It also has possible application to heating and cooling. Whether compressed air is a wise choice for automobiles, I doubt, but I haven't looked into the problem in any detail.

3 minute fill-up at the station.. 3 hours at home.

http://www.cyber-media.com/aircar/ the MDI Air Car the sell modular factories.. they are anti Globalists.. they sell Kit Factories for local production..

All this does is convert energy from one medium to another, something must drive the air compressor. There will be losses in the conversion. If the whole thing could run on renewable fuel resources, it would be great, but, it just isn't the case yet.
I wish these guys well, but they ain't ready for prime time.

full cycle. Comparable to batteries. This is for large grid storage installations, probably using centrifugal compressors.

Grid CAES systems compress the air using off-peak power, then burn it with natural gas on-peak. It's more like a turbo-charged gas generator than a "pure" storage set-up.

in the turbine, eliminatign the ~30% loss used to power the turbine. Neat Idea, but still uses natural gas. Big in Germany, I think.

I have a cheapo mountain bike with a Wilderness Energy 600 watt front hubmotor, it rocks! I am somewhat disabled, want to go places I can neither walk, because of disability, or drive, because of environmental concerns. It costs less than ten cents to charge my batts {3X 12 volts} good for 18 miles on hard roads, 8 or 10 miles riding on state park trails where I go looking for photogenic critters.
Once I have the batteries charged, I can run the bike with almost no environmental effect, but the power company is still burning something, so I can charge the batts, to begin with.
It beats hell out of running my 50CC motor scooter on the state park trails, but all it really does is move the stink to somewhere else, I am burning even more fossil fuel, because of the conversion losses. 70% sounds decent, but, it still means that 30% is pissed away. Overall, the 50CC Chinese motorscooter may actually be more efficient, and less polluting, just because there is one less conversion loss.
I am hoping that I will be able to hit contributor level out of next months SS check, I really want to be able to post on the restricted forums.
In the meantime, any of you want advice on how to keep a Chinese electric bike, or a Chinese motorscooter running, give me a shout!:toast:

Sorry to steal anyone's thunder but someone did post about this new system some time ago. This should not take away from the innovation though. I personally thought UPS had already done its trial and evaluation.

What is new with this article was that I thought that UPS and some R & D firm had developed the system for UPS' own use. Guess I was wrong on that note. I had no idea that EPA had developed the system.

Watch, our typically clueless U.S. auto manufacturers will not want nothing to do with it. Why? Because it is innovation, that's why.

of the breaking "energy" into forward motion than is the current hybrid-electric setup because the current batteries cannot absorb the electrical charge as quickly. New quick charging batteries under development may mitigate the quick charge problem.

Does anyone else remember something like that? Or is my aging mind playing tricks on me.

I wonder if this system would also work well on city buses and school buses, as the hybrid-electric does.

how much effective braking horsepower,
can the batteries in the Prius absorb in electricity?

don't assume it is the same as the power rating
of the electric motors, it is probably much less.

of course, Toyota never talks about this.

regen braking is mostly a scam,
on the other hand, you have to start somewhere

It was a mild-hybrid pickup truck, it got about 15% additional mileage.