Topic: Goodbye heat sink material, hello ceramics! (Read 1668 times)

Jack Morris · « **on:** March 27, 2005, 10:05:26 pm »

http://biz.yahoo.com/bw/050327/275006.html?.v=1

Those Japanese really are science oriented people! I remember in the late 80's they were pushing ceramic engines for cars, they had high temp lasers striking a ceramic engine to show just how heat resistant it was!

I also visited a Honda dealership in Austin, I did not see any supposed 3k dealer add on for the hybrid civics, but they run 2k plus over a gas powered car. I found out the reason for the increase, it's called very high demand! They did not even have a hybrid accord available on the lot!

Hybrid civic gets 48 city, 52 hwy!

Commander Maxillius · « **Reply #1 on:** March 29, 2005, 07:42:53 pm »

hybrid Accord gets something like mid-30's hwy.

If I'm going to pay for a 6000 option like hybrid drive, I would think it would be for more than a 5 MPG increase

Death_Merchant · « **Reply #2 on:** March 30, 2005, 11:25:17 am »

DM's tech rule-of-thumb: Never EVER buy v1.0 of anything!

The Accord and most if not all new hybrids use NiMH batteries. These have many advantages over lead-acid or Ni-Cd, but one thing still really has yet to be shown: long term reliability

The sticker price of the Accord hybrid over a similar non-hybrid means you must drive about 100,000 miles to recoup your initial outlay (even assuming CA gas at $2.50/gal). This is assuming the battery pack does not need to be replaced before that. If so, factor in another $4-6K.

I'm hoping hybrids take off, but I'm not comfortable buying one just yet....

Sirgod · « **Reply #3 on:** March 30, 2005, 11:27:50 am »

There was talk of Creating Iridium Based Super Conductive Ceramics, and alot of Research put into it a few years back. Basicly they would be superconductive at Room temperature. Essientially Electricity could flow through wires made of this stuff (even though It's not Metal) without raising the Temperature at all.

I'll try and find the article again, but Like I said It's been years ago.

Stephen

E_Look · « **Reply #4 on:** March 30, 2005, 11:32:12 am »

Boys, think about one thing for a sec...

... it's going to be ceramic- too heavy and brittle to make engine blocks from! Maybe as Jack said, only for heat sinks, but ceramics are generally poor conductors of anything, except for those famous "high Tc" superconductors.

Commander Maxillius · « **Reply #5 on:** March 30, 2005, 09:53:09 pm »

Perhaps if it were a hybrid material, say, a type of plastic or metal latticed within the ceramic material, like rebar in concrete...

also consider that they may not *have* to make engine blocks out of the stuff. A superconducting ceramic motor can be made smaller since less energy is wasted, so the added weight of the ceramic can be offset by decreased weight of fewer batteries and increased power of the motor.

KOTH-KieranXC, Ret. · « **Reply #6 on:** March 30, 2005, 11:14:53 pm »

Quote from: Maxillius on March 29, 2005, 07:42:53 pm

hybrid Accord gets something like mid-30's hwy.

If I'm going to pay for a 6000 option like hybrid drive, I would think it would be for more than a 5 MPG increase

hell, my used 96 Sunfire gets 35 mpg on its own, and that's with a conventional gas burning engine...

Death_Merchant · « **Reply #7 on:** March 30, 2005, 11:23:28 pm »

Quote from: Maxillius on March 30, 2005, 09:53:09 pm

Perhaps if it were a hybrid material, say, a type of plastic or metal latticed within the ceramic material, like rebar in concrete...

Much research has been done in this area, and the rebar analogy is good but not quite accurate.
Rebar is used in concrete because while very strong in compression, concrete has poor tensile strength. The rebar is used to take the tensile loads, not necessarily to stop cracks from forming and propagating.

Most research in high-temp brittle ceramics has been to increase the toughness (resistance to crack growth). The best reinforcements are not long continuous "fibers" like rebar in concrete, but small whiskers. Additionally, you want to design the fiber/matrix interface to slip. It is this microfiber pullout that dissipates energy and blunts cracks. It's called "crack bridging" in the literature.

DM pauses, realizing he is even boring himself.....
Sorry folks...

Hmmmm.... "Report to Moderator" link...
I should report myself. I suk. Lame-ass posting...
I wonder what happens? Will I get a electrical keyboard shock? I ban myself? Kewl!

Commander Maxillius · « **Reply #8 on:** March 31, 2005, 09:22:39 pm »

it's actually not boring, but enlightening

suppose if an engine could have very thin metal cylinder walls and heads, but a ceramic block surrounding the metal, with vanes of metal running out into the ceramic to dissipate heat from the metal to the ceramic material...

Death_Merchant · « **Reply #9 on:** March 31, 2005, 11:47:31 pm »

A metal liner would need to be diffusion bonded to the ceramic. A simple mechanical interface makes for a lousy thermal interface.

And you're still left with the fundamental problem: a ceramic engine block prone to cracking

There are design ways around that, but now you defeat the whole purpose. For a little bit of efficiency improvement, you've built yourself a hugely complicate engine with questionable reliability. The cons just got bigger than the pros.....

Jack Morris · « **Reply #10 on:** April 01, 2005, 08:54:46 am »

Good to see you DM, I've been wondering where you have been hiding!

Grand Master of Shadows NCC37385 · « **Reply #11 on:** April 01, 2005, 09:33:29 pm »

Ive been telling people for years that they need to invest in my Perpetual Motion Automobile. Please send all investment monies to my personal account at the Grand Cayman National Bank...

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