| Author | Message | ||
| Ben Cannon (Artherd)
Member Username: Artherd Post Number: 878 Registered: 6-2002 |
Nebula- the metal temp should be within a few degrees of the water temp for alloy blocks (aluminum is a GREAT heat conductor, and quite efficent.) Iron blocks can get a tad warmer, not much. 10-20 degrees tops. (any expierenced engine guys have more exact figures?) The trick is how conductive is the medium, how much heat can it dump into the water jackets. And the answer with metal engines is basically; all of it  Carbon has a higher conductivity than Aluminum infact, but when done in a composite with epoxy (effectively an insulator now.) the value ranges from 1/5th to 1/10th that of aluminum. It varies all over the map however. The only really hot (hotter than water temp) area on an engine is the exhaust valves <because>, and the headers (though they're outside the engine proper...) There are other issues, britality being the biggest. Carbon and carbon-fibre are BRITTLE mo-fos! Some things can be done with filiment layup, and epoxy selection... and the low COE is on your side... This all really should be solveable soon though. Best! Ben. | ||
| PSk (Psk)
Member Username: Psk Post Number: 939 Registered: 11-2002 |
I'm sure I have seen an add for a carbon fibre engine in an English race mag. It was a 4 cylinder. When you think about it a block is extremely simple. Chuck in some steel (or alloy) liners and some sleaves for the crank bearings to attach to, seal the water jackets and away you go. Would you save any weight? Plus the big negative and why this is not used in F1, etc. is that when carbon fibre fails it is all over ... and what happens to the race result if this was on the last lap!!!!. A alloy or cast iron block might just hold together enough to finish ... and once you add all the other components required for a working short block you probably save F**k all, if anything. I even believe that many F1 blocks are now cast iron due to thin wall casting techniques that have made them light enough. Remember that Renault used to use conrods that were some sort of complicated layered manufacturing process ... but they went back to steel for ease of quality control (I believe) Pete | ||
| Nebula Class (Nebulaclass)
Member Username: Nebulaclass Post Number: 447 Registered: 11-2002 |
Hey Ben....with a really efficient cooling system, what does a typical block's temp get to? Excluding around the cylinder head, doesn't the heat dissipation, the oil lubrication, and water/coolant cooling keep the block "relatively" cool? | ||
| Ben Cannon (Artherd)
Member Username: Artherd Post Number: 861 Registered: 6-2002 |
bumpidity, can't let this die! | ||
| Ben Cannon (Artherd)
Member Username: Artherd Post Number: 858 Registered: 6-2002 |
Ferrari has also dabbled with CF frame gearboxes, though they went back to Titanium recently. The CF cases require bushing with aluminum (which must first be chemical-coated using an insulative process to prevent electrical corrosion with raw CF.) Also a few layers of S-glass can be used to provide more 'rugged' mounts (S-glas is much less brittle than CF.) The real problem, is building something as complex as an engine's shape. CF lays up like sheets of paper. a 4-cyl or opposed boxer might be an intresting excercise. I'd hate to try a vee though! Lastly, CF's COE (how much it expands with temprature) is very low, lower than almost all metals. Teflon breaks down at too low a temp (few hundred F) to use as a dry-film lubricant on a motor. DFLs in general work great with low or no side-load, and pistons/cranks place HUGE sideload on bearings! Carbon/epoxy composites are really limited by the epoxies. Beyond 500F, there just aren't many out there. The 500F stuff is fairly exotic, with most expxies in teh 250-350F service/cure range. Epoxy Tgs (melts at the polymer chain level) above it's rated (and sometimes cure) temprature. Carbon/ceramic hybrids have been used, with no metal in the engine, no cooling system was required at all... it operated at 1200C all the time Keep thinking! Ideas like this, that break the mould, are what human ingunity is founded on! Best! Ben. | ||
| Taek-Ho Kwon (Stickanddice)
Intermediate Member Username: Stickanddice Post Number: 2087 Registered: 11-2002 |
At the risk of sounding dumber than I already am...I just invested in the company. I don't have much insight into what the projects are. I am told what we can do and they try and wow me with their innovations so that I would pump in more money, but in essence, it's a brain trust with a division that actually manufactures the stuff and the products. We do some crazy things with CF. Like clipboards and key chains. Feel free to PM me about this stuff. I too find it fascinating. I'm on a trip to Houston right now so won't be checking my mail until I return to San Francisco on Saturday or Sunday. Cheers | ||
| S. Brent Cardani (Brentc)
New member Username: Brentc Post Number: 43 Registered: 8-2003 |
Taek-Ho, I'm fascinated by the stuff. If I were younger, I'd go back and get a degree in it. When I would visit my friend at school, I'd read his textbooks because I found them so interesting. I'd love to talk off-line about what you do and your company. | ||
| Taek-Ho Kwon (Stickanddice)
Intermediate Member Username: Stickanddice Post Number: 2085 Registered: 11-2002 |
BrentC, It's definitely very interesting stuff, isn't it? I own a company that does composites work for military, aerospace, and marine applications and some of the stuff they touch is soooooo far ahead of anything most people get to see. It's fun just hearing about it! Cheers | ||
| S. Brent Cardani (Brentc)
New member Username: Brentc Post Number: 42 Registered: 8-2003 |
Arrows F1 team used/uses a CF gearbox casing. It was featured on the cover of Racecar Engineering about 2 years ago. Not the same as an engine, but they did address some of the same issues being discussed here - porosity, etc. Also, have a friend who did his PhD dissertation in Materials Science on "self-healing" materials (destined for military use). They were composites made with fibers that had resin embedded in them so that in the event of penetration by a projectile, the resin would "leak" out and re-seal the panel. How's that for a high-tech tank? | ||
| William H (Countachxx)
Advanced Member Username: Countachxx Post Number: 3032 Registered: 2-2001 |
I think some light weight ceramics may work better, there already are jet turbine & turbocharger blades made out of high temp ceramics. I remember a race car with a plastic engine that was in the 1982 GTP season. Thing was constantly breaking. I dont know enough about CF in high tempratures to opine | ||
| rob guess (Beast)
Member Username: Beast Post Number: 319 Registered: 5-2003 |
Neb; Try a goggle or yahoo search on "Polimotor" This was the motor built out of plastic and even raced if i recall a few times. The main factor here is cost iron and Aluminum are cheap easy to work with and recyclable. Carbon Fiber is tough to work with and is still not a truly understood material. Recall that several F1 teams have tried CF trans cases but had to use Titanium bulkheads to hold the shafts. they had several failures with them. | ||
| Nebula Class (Nebulaclass)
Member Username: Nebulaclass Post Number: 434 Registered: 11-2002 |
Wouldn't it be bitchin' though? | ||
| Taek-Ho Kwon (Stickanddice)
Intermediate Member Username: Stickanddice Post Number: 2081 Registered: 11-2002 |
Carbon fiber would become brittle and unstable in these high temperatures after prolonged use. There are carbon/carbon graphite composites that can withstand tremendous temperatures (in the thousands of degrees Fahrenheit) but one has to be realistic in it's application. Cheers | ||
| Rikky Alessi (Ralessi)
Member Username: Ralessi Post Number: 325 Registered: 5-2002 |
I think I read something once about the carbon fiber engine internals not being practical because they do not expand like aluminum/steel does, and it would throw off the current specifications/tolerances. Also I think the rules may prevent carbon fiber blocks. | ||
| '75 308 GT4 (Peter)
Advanced Member Username: Peter Post Number: 3085 Registered: 12-2000 |
Ford experimented back in the late '70's and early '80's with their "plastic" engine (loosely based on the Cosworth four-cylinder design). It featured a block made in some kind-of thermosetting plastic, but the rest of the engine was mostly metal (obviously cylinder liners, head, valves, crank, etc). I think the connecting rods were made out of some fibre material. I remembered it being featured in a Popular Science (or Mechaincs) magazine during that above-mentioned time and they said it cost Ford a fortune to research and develop... | ||
| Mark (Study)
Member Username: Study Post Number: 791 Registered: 10-2001 |
In the name of fast response modern military. The Brits are driving around on military base in a new carbon fiber, plastic tank. Their goal is to have a tank that is light enough to be air-lifted into battle. Yet still strong enough to take a major hit. If they can build a tank... why not an engine block? | ||
| William H (Countachxx)
Advanced Member Username: Countachxx Post Number: 3031 Registered: 2-2001 |
how about connetcing roda made of artificial diamond ? How many carats would that be at $5 per carat ? Maybe diamond valves would be more practical | ||
| Hubert Otlik (Hugh)
Intermediate Member Username: Hugh Post Number: 1378 Registered: 1-2002 |
Nebula- not strange at all. I'm sure F1 teams will be the first to do it, if it happens, but the problem is lead time, and the (alleged) incoming regulations ( 1 engine/ weekend, etc.). It takes months of lead time to make one c/f rotor... imagine the lead time for a block, pistons, head , crank, etc.????? It's a great, nevertheless. | ||
| Nebula Class (Nebulaclass)
Member Username: Nebulaclass Post Number: 426 Registered: 11-2002 |
Here's my thought, Hubert. CF blocks are probably quite unpractical in terms of longevity and strength. The same would go for any sort of teflon-like substance used on moving parts. But what's the probability that F1 teams are using materials like this? I would assume, since the engines are essentially only good for one race, that they are using this kind of stuff in order to get that "one-up" on other race teams. Who knows, though? We may never know, as all F1 engines are held under severe secrecy by the builders and race teams. I just find myself often sitting in traffic or at home or whatever, thinking up odd things like teflon engines or cf engines. Strange mind, I guess. | ||
| Hubert Otlik (Hugh)
Intermediate Member Username: Hugh Post Number: 1377 Registered: 1-2002 |
Sure you could start sleeving the cf, but then (from the point of pragmatisim) what would be the utility of using CF for the remainder when Al is cheap (fairly) , is readily available and rather light? About the torsional strain... what I'm saying , if you put a bolt through a section of cf, how do you stop it from cracking, even if you brace it? CF crumbles, and spider webs; then again, the engine would be lighter, so the torque applied to it may not be a threshold value, but I don't know... it's not a bad idea, at all (I've had the same thought many times) BTW, berillyum used to be used in calipers and blocks by various F1 teams, but not only is it toxic (the dust is), but it's retarded expensive... makes Titanium look like tin. | ||
| Nebula Class (Nebulaclass)
Member Username: Nebulaclass Post Number: 424 Registered: 11-2002 |
Well, in terms of a cf engine, the cylinders could easily have sleeves, as could all the water/oil passages. Also, steel supports could be used to brace the block against any torsional strain. With the cylinders and water/oil passages sleeved, would there still be a problem with seepage through the cf? And, if I'm not mistaken, hypereutectic (fancy cast)pistons are fairly strong and long lasting. I know guys that run them in blown 500hp Mustangs and the pistons never crack or melt. | ||
| Hubert Otlik (Hugh)
Intermediate Member Username: Hugh Post Number: 1374 Registered: 1-2002 |
How would you seal the block? C/F by nature is porous which is why,incidentally, it's a good dissipater of heat; you could make carbon fiber oil pans, and such... (it's already been done, actually). If you encase / shroud it with a sealent coating , how will you disapate heat? Nothing is friction less... ever. Teflon is a chlorine / methyl composite coating (Cl and C bonds are robust ; i.e. , strong enough to render the molecule not readily reactive) coating... it works simply b/c it's inert, chemically, therefore bonds aren't formed, but there's always heat to worry about.. prolonged heat. Once you build up heat inside it all the bearings/joints will begin to fail. Also, the ceramic/cf composites used in brake systems still have elements of metals in them ; they're not pure fiber. Also, w/ cf and the temps that are seen under combustion how you keep from elements in the air from fusing to the fiber? Further, pistons are already coated with Nikasil (as are the cyl. sleves), and manufactures are using FRM sleeves to lower the overall weight, but he problem then is, a forged piston won't seal agains the FRM sleeves, so... you've got to use cast pistons, which I guess you could sanddown to make a bit sturider, but cast pistons won't hold indefinatly. Also, how are you going to insulate the carbon block from torsinal strain (i.e., when you accelerate the car, and the motor gets torque?? if you over dampen the motor mounts the whole car will feel like rubber). | ||
| Nebula Class (Nebulaclass)
Member Username: Nebulaclass Post Number: 419 Registered: 11-2002 |
no thoughts? | ||
| Nebula Class (Nebulaclass)
Member Username: Nebulaclass Post Number: 417 Registered: 11-2002 |
I was wondering.....since some manufacturers are using carbon fiber for high-stress parts such as brake disks and clutches, why would a carbon fiber engine block not work? It would be light as hell and would dissapate heat relatively well. I would venture to guess that carbon fiber samples have been made with some pretty heavy resin, abe to withstand the pressures that a normal block goes through. Second, is it possible to make an oil-less engine by using teflon? Assume that your cylinder and pistons are coated with teflon, and the pistons are fit almost exactly to the diameter of the cylinder, so close, in fact, that it is able to move and not use rings. Now, metal on teflon slides, but teflon on teflon is damn near close to friction-less. Also assume that the cam journals and the camshaft, as well as the rollers, are coated in teflon. Finally, assume that the crank shaft is coated in teflon, as are the rod bearings. Now, I don't know the dynamics of teflon, but I do know that it can stand up to pretty high temps, and I'm pretty sure that teflon in contact with teflon will not damage it. Am I totally off base here? Wouldn't a teflon engine greatly reduce any friction in the up/down motion of the pistons, the rotation of the crank, and the valvetrain movement, also killing the need for oil? Am I retarted? I need a scientist to smack me with a shovel and tell me all the dumb things I've missed in my brainstorming. |