Recent Comments:
Air Car will be released this year thanks to $30 million from Tata {Autoblog Green}
Feb 14th 2008 3:38PM ronEbear said:
Air in a tank vs. Flammable fuel in a fuel tank
Air in a tank tank vs. chemical-laden batteries
Air tank wins.
I have concerns about the ability to build a large/safe compressed air tank in the vehicle without dipping into expensive things like carbon fiber.
But the bigger problem is the overall efficiency of the system. Compressing/expanding air brings all kinds of thermodynamic losses into play. A significant portion of the energy used to compress air is transferred into heat rather than into pressure. That heat is then lost to the atmosphere. When transferring from a compressed tank at a filling station to an initially lower pressure tank in the car, the gas will be agian expanded then compressed, pumping more energy into and out of the system, and again some will be lost. Once in the tank, expanding the compressed air will cool it, reducing the energy you can extract from it. I've heard it theorized that such a system only works in hot climates where 1) you can more easily prevent your air motors from literally freezing as the expanding/cooling air flows through them and 2) you can extract some heat from the environment to counteract the cooling effects (think themal fins all over everything).
For anything other than free solar energy, the efficiency will probably be terrible. And then there is the fact that the longevity of a high pressure tank that is frequently pressurized/depressurized could be questionable. And the fact that the infrastructure to support this new fuel source isn't there - don't try to think you can charge the tank on a standard gas station compressor in 2 mins - you'd need a high pressure reservoir to accomplish that, with specialized connections and safety systems.
And even for that free solar energy - don't count on a full system with high pressure tank and large solar array being able to fill up more than a handful of cars each day at best.
I'm a pessimist on this technology. Prove me wrong Tata/MDI! Please!!!!!
Meet the MarySlim, a Very Slender Vessel {Autoblog Green}
Feb 13th 2008 12:37PM I agree with rgseidl - this is definitely not green.
For a better approach to an efficient, slender cruising vessel, check out the Dashew FPB series: http://www.setsail.com/dashew/do_PARADIGM.html
The Dashew FPB 64 is powered by a 236hp motor - compare that to the MarySlim's 1650 hp motor and decide which is a good example of green design. Even the FPB 83' version only uses dual 150hp motors.
It's not a 'new' boat, but much more worth of an ABG mention than this monstrous jet ski. If only I had a few million bucks to spend....
Chicago 2008: North American Debut of the Toyota 1/x {Autoblog Green}
Feb 6th 2008 3:01PM For a 'real' example of this type of thinking, look at the Loremo. The Loremo doesn't rely on carbon fiber for its light weight, doesn't rely on an expensive hybrid powertrain for efficiency, and still achieves over 100mpg with the smaller engine option (77mpg with the larger engine). Total weight for the Loremo is about 1300 lbs. That's about 350 lbs more than the 1/x, but it's real and can realistically be produced to meet crash specifications (includes crumple zones and airbags).
Video: 130 MPG Ingo car gets local news coverage {Autoblog Green}
Jan 31st 2008 11:27AM I'm still not convinced that this design offers significant benefits compared to the air car - it would seem to me that in either case you are compressing and expanding air (a sealed nitrogen bag in this case) in order to store and extract energy. The heating and cooling of the air as you compress and expand the air means that some of the energy from the ICE and even from the regen braking will be lost. I didn't do the calculations myself, but detractors of the air car concept seemed certain that these losses made the whole system a poor idea. If the only difference is the efficiency of hydraulic motors vs pneumatic motors, I'd be skeptical of the claims.
Theoretically, one might use the hydraulic fluid surrounding the nitrogen bag as a heat sink - absorbing the heat of compression and returning it to the expanding air - to reduce the losses. But I can't picture a flexible bag covered in cooling fins to make the transfer happen.
Hopefully Ingo will build at least one prototype and prove somebody right and somebody wrong!
On the plus side, it seems that the interesting part of this design is the hydraulic system, not the free piston pump. Another more proven compressor design could easily be used if the free piston pump proves problematic.
Also on the plus side, the T shaped tank arrangement would be an automatic fit for something like the XR3 (http://rqriley.com/xr3.htm) - heck it practically matches the XR3 layout perfectly. If the drive concept actually works, it'd be a cinch to redesign the XR3 around it. The XR3 is supposed to be only 1300 lbs and have a very low drag coefficient. If tanks could be made reasonably cheaply (carbon fiber pressure vessels don't sound DIY friendly), this would simplify the XR3 systems considerably. And that's a good thing :-)
Video: 130 MPG Ingo car gets local news coverage {Autoblog Green}
Jan 30th 2008 8:00PM According to the official website:
The piston of the free-piston internal combustion engine pumps hydraulic fluid into the accumulator. It stores the energy by compressing the gas bladder inside. The engine will be turned off automatically when the accumulator is filled – and turned on again shortly before it becomes empty.
The pressurized fluid drives the wheelmotors, one in each wheel.[...]
The wheelmotors are reversed during braking and become pumps.
It sure sounds like the Ingo car is simply compressing air with the ICE, and using that stored energy to drive the wheels. The only difference between this an a 'true air-car' is that the air car uses air to drive the wheel motors, while this uses the air pressue to push hydraulic fluid through the wheel motors. In either case, the energy is going ICE -> pressure wheel, and the inefficiencies involved in converting pressure to work will be involved.
If the ICE was only driving the hydraulic fluid directly through the motors rather than compressing an air bladder, the wheel HP would only be equal to the ICE HP minus hydraulic transmission losses (which are considerable). If so, why are they bothering with the hydraulic transmission at all?
The Ingo car is simply an air-car with hydraulic fluid mixed in. Right? Is this just hype like air-car hype?????
Video: 130 MPG Ingo car gets local news coverage {Autoblog Green}
Jan 30th 2008 6:00PM Why is this different from the 'air car' that seems to be dismissed by readers of this blog? People were saying that the inefficiencies of compressing air and then using it to perform work were insurmountable, that the only way it was worth it was if the energy to compress the air was essentially free (e.g. a wind turbine on your garage).
Now the Ingo car is using an onboard ICE to compress a nitrogen bladder in the accumulator. Do the same inefficiences not apply for some reason?
