http://www.technologyreview.com/energy/24701/
They admit using a catalyst and preheating the fuel on top of autoignition
-
March 8, 2010 11:01 a.m. Raze HalfDork
-
March 8, 2010 11:43 a.m. klipless New Reader
Is this the same thing as HCCI (homogeneous charge compression igntion)?
-
March 8, 2010 11:49 a.m. alfadriver Dork
Yea, it sounds just like HCCI. Nothing really revolutionary, but I did find it interesting to use a catalysts on the fuel.
Since a catalyst is used to promote a reaction of some type, what reaction are they trying to achieve? You can't oxygenate a fuel without oxygen.
I remember being contacted by a person trying to sell me a similar technology, who claimed that the catalyst broke the fuel down into hydrogen and carbon, and then further converting carbon to hydrogen. I told him that if that was actually happening, he would be dead from the radiation given off- he then replied that it would explain why his credit cards were being erased.... Oook.
And then he told me that since he didn't take physics in HS, he didn't believe that radiation would be given off when carbon broke down to hydrogen... I'm not kidding he told me that.
But I'm not saying this is what is happening here. If it is, shame on MIT...
Eric
-
March 8, 2010 11:50 a.m. MadScientistMatt Dork
klipless wrote:
Is this the same thing as HCCI (homogeneous charge compression igntion)?
Looks like it.
Also, while that article claims their test car has "similar aerodynamics" to a Prius, it looks to me like it's probably got about the same coefficient of drag but half the frontal area. I suspect a fair slice of their MPG claims are because of what they put the motor in.
-
March 8, 2010 12:04 p.m. klipless New Reader
In reply to MadScientistMatt:
Yeah, it'd be nice if they stated their claims in brake spec fuel consumption, but then they couldn't get the wild headlines b/c no one would know what they're talking about.
-
March 8, 2010 12:27 p.m. 4cylndrfury SuperDork
-
March 8, 2010 1:01 p.m. Raze HalfDork
4cylndrfury wrote:
I agree at first blush this looks like snake oil, not because of the HCCI and improved control but because of the term 'catalyst'.
I still want to know more about the catalyst + fuel heating, I'd like to take a look at their chemistry...
I know from my unsteady combustor injector research in gradschool that with the right injector (read expensive compared to automotive injectors) + heating of the fuel, you can achieve smaller droplet size/ better atomization thus increasing the homogenousness of the mixture and combustion efficiencies on the order of %'s but this is in something like a turbine. There is a tradeoff in emissions and mechanical wear. The difficulties of acheiving similar efficiency improvments in a more volatile timed pulse detonation environment are higher but can be done...
And as has been pointed out, I'd like to see that engine in a jeep wrangler with the relative efficiencies tested...
-
March 8, 2010 1:29 p.m. mrwillie Reader
Along the same lines....does anyone know if these work?
http://somender-singh.com/content/view/7/31/
http://www.google.com/search?q=singh+grooves+cylinder+head&ie=utf-8&oe=utf...
I've tried them on a few lawnmowers and a chipper, and the mowers seemed to use less fuel and run better, but it could be my imagination. I have nothing at all to back these claims up. Anyone tried these b/4??
-
March 8, 2010 1:33 p.m. alfadriver Dork
While fuel heating is interesting, and quite useful, after a while, the injectors are flash vaporizing the fuel as it comes out of the injector. It happes on port injected engines and it happens on DI engines. All the heating does is make it happen sooner. And it is a good think- especially for direct injection (less drops = less smoke)
But the point is that you don't need a heater to inject vapor, just a nice warm engine. At 39psi, the fuel will flash vaporize at about 150F engine temp, at 1000psi, it's closer to 180.
The words they use for the heater makes it sound quite dubious.
The Catalyst, though? Yea, give me the chemistry that you are attempting before I even consider buying.
E-
-
March 8, 2010 2:12 p.m. Trans_Maro HalfDork
I did some reading on the Singh groove idea.
Apparently it works well until the grooves load up with carbon and you start getting detonation. Then your crap-gas-using, high-compression motor becomes just another premium-drinking high-comp motor.
Shawn
-
March 8, 2010 2:56 p.m. mrwillie Reader
In reply to Trans_Maro:
Well, that explains alot. One of the mowers that I tried it on wound up running really bad one day and had a bunch of craters on the piston and the head( I guess that's what you call in a mower engine.. ). The other mower never ran right after the second polish job on the chamber. One and a half years on free "dead" CL mowers made it easy to experiment and write off later. Is it a good idea to run a mower on E85?
-
March 8, 2010 3:01 p.m. klipless New Reader
mrwillie wrote: . Is it a good idea to run a mower on E85?
I don't see why not. It's not like you're concerned with mileage or anything. The higher octane might even help if the engine has a lot of carbon build-up upping the compression. The only thing to watch out for is that ethanol and certain kinds of plastics don't get along too well. It might dissolve the tank a bit, and no one wants to have that crap flowing through their engine.
Maybe if you only keep it in the tank while you're using it, then flush or dilute it with some regular gas.
-
March 8, 2010 3:16 p.m. kb58 Reader
alfadriver wrote: ...he told me that since he didn't take physics in HS, he didn't believe that radiation would be given off when carbon broke down to hydrogen...
I don't know whether to laugh or cry. So becausehe didn't take classes, what they teach doesn't apply to him... priceless. Reminds me of aluminum-frame Locost builders to whom metal fatigue doesn't exist because they haven't read about it. Or, builders who come up with a really bad suspension design, insulting those who point out problems as "you're living inside a box created by your schools and books." Unfortunately (or fortunately) physics and the laws of nature overrule positive thinking. Just priceless. -
March 8, 2010 5:08 p.m. Toyman01 Dork
Open intake, lean run and direct injection and no ignition sounds like a diesel to me. What kind of mileage would a diesel of comparable size and power get. 68 MPG sounds great, but what size and power engine. If it's a 1 liter at 60hp, that's one thing. If it's a 6 liter at 400hp that's a whole different story.
The only info I could find on the car was it was "mid sized" and the test was done on a chassis dyno. I'm not sure how you can get a realistic number on a dyno. Not much wind resistance on one of those.
-
March 8, 2010 5:12 p.m. ignorant SuperDork
Right now HCCI is hard to control.. Period! I know people that have it down, but only in very narrow RPM bands. They're going to utilize it for generators, because they run at one point with little variation(hint, probably natural gas first.). transients are hard to control with HCCI atleast right now.
-
March 8, 2010 5:26 p.m. John Brown SuperDork
mrwillie wrote:
Is it a good idea to run a mower on E85?
As long as your mower has Megasquirt and a KKK K03 turbo on it.
-
March 8, 2010 5:30 p.m. Raze HalfDork
ignorant wrote:
Right now HCCI is hard to control.. Period! I know people that have it down, but only in very narrow RPM bands. They're going to utilize it for generators, because they run at one point with little variation(hint, probably natural gas first.). transients are hard to control with HCCI atleast right now.
x2
-
March 8, 2010 5:43 p.m. paul New Reader
http://www.seattlepi.com/local/351903_needle20.html
...recently rediscovered the souped-down 1959 Opel T-1 that achieved 376.59 miles per gallonin a 1973 contest. (Photo by Cosmopolitan Motors)
-
March 8, 2010 5:53 p.m. John Brown SuperDork
ignorant wrote: transients are hard to control with HCCI atleast right now.
I was under the impression transients were easy to control once you added alcohol.
-
March 8, 2010 7:58 p.m. alfadriver Dork
Toyman01 wrote:
Open intake, lean run and direct injection and no ignition sounds like a diesel to me. What kind of mileage would a diesel of comparable size and power get. 68 MPG sounds great, but what size and power engine. If it's a 1 liter at 60hp, that's one thing. If it's a 6 liter at 400hp that's a whole different story.
The only info I could find on the car was it was "mid sized" and the test was done on a chassis dyno. I'm not sure how you can get a realistic number on a dyno. Not much wind resistance on one of those.
Ignoring the problems that Ignorant posted- all of which need solved... In theory, you get the best of both worlds- the possibility of lean combustion/diesel kind of system + gasoline power (equal displacement engines gas> diesel in power, assumed that both are boosted). The other theory is that the hardware required to run HCCI is still cheaper than diesel. That's why so many are trying to make it work.
We will see. It's still a long way out.
Eric
-
March 9, 2010 7:55 a.m. klipless New Reader
ignorant wrote:
Right now HCCI is hard to control.. Period! I know people that have it down, but only in very narrow RPM bands. They're going to utilize it for generators, because they run at one point with little variation(hint, probably natural gas first.). transients are hard to control with HCCI atleast right now.
Yeah, the few articles I've read on it mention that all the companies that have a car using it still use spark at low and high rpms. Get the gearing right, and you can see some great highway mileage.
-
March 9, 2010 10:30 a.m. MadScientistMatt Dork
I've heard one reason to avoid copper fuel fittings is that it has a catalyst effect: It breaks the fuel down into gum and varnish. Doesn't sound like you would want to do that on purpose.
-
March 9, 2010 11:43 a.m. Jensenman SuperDork
Honda has been there and done that wayyyy back in 1998. Won their class in Baja with it, too.
http://www.motorcycle.com/manufacturer/honda/quick-take-honda-exp2-15170.html
