h a l f b a k e r yThe Out-of-Focus Group.
add, search, annotate, link, view, overview, recent, by name, random
news, help, about, links, report a problem
browse anonymously,
or get an account
and write.
register,
|
|
|
My idea is to have an engine with electromagnetic bearings, so the crankshaft, cam, and other bearings float inside the engine without any friction, or just take a friction load off the bearings. The magnets would need to be on the crankshaft journals, and also where the bearings would normally go. They
would need to be electrically charged to intensify the effect of the magnets, and keep them from touching. Of course, magnet strength is probably the first thing that would make this engine impossible, just an idea though
magnetic monopole geometry
http://www.matchroc.../ether/halbach.html
[beanangel, Mar 11 2008]
ironless airplane motors
http://www.grc.nasa.../RS08S-kascak2.html
At the NASA Glenn Research Center, our approach is first to improve the heat removal from the stator, by using forced-convection heat transfer, and second to improve the magnetic flux circuit with a Halbach Array. This will eliminate the need for an iron core [beanangel, Mar 11 2008]
[link]
|
| |
I think you've figured out for your elf why it probably won't woik; the forces acting on an engine bearing are immense. |
|
| |
They already float without any friction !
engines use hydraulic bearings, meaning the bearings and
the crank dont make contact with each other, they float
inside a film of oil, which is what the oil pressure is for.
Which means there is little to no friction, smokey yunik
built an engine with roller bearings once and it made no
difference in hp. |
|
| |
Yes, what the (appropriately named) [liquid2] said, except for the "without friction" part which is quite false. Oil can be slick but not that slick. |
|
| |
You'd still have to seal it somehow... |
|
| |
the cost involved with such an arrangement, as well as the weight, size, the unavailability of superconductors required, ect.... makes this idea interesting, but in no way practical or appliable. With the level of technology needed for this type of arrangement, wouldnt it be better to ditch the internal combustion engine alltogeather? By the way, modern engines use clearances and materials that allow conventional bearings to last well over 250,000 miles. The cost to benifit just isnt there (even if it were technically possible.) |
|
| |
The US Navy has a nuclear submarine with magnetic bearings in the turbine generators. Unfortunately every time it goes to sea one of the bearings fails and it has to limp back home with only one turbine generator left. I think they're planning to refit with conventional bearing turbine generators if they haven't already. Good idea but it seems the benefits don't justify the intense R&D needed to make them reliable. |
|
| |
If you're going that far, why not go
all the way and make vacuum-
magnetic bearings? Then you
really have no friction at all to
worry about. |
|
| |
I do recall an experiment, though,
where a moving magnetic field can
induce an electrical (and, hence,
opposite magnetic) field in a non-
magnetic metal, causing a force in
the opposite direction to
movement. It's usually
demonstrated by dropping a
magnet down the center of an
aluminum (yes, I'm in north
america) pipe. The magnet falls
slowly thanks to the little eddy
currents. |
|
| |
Think that might be a problem? |
|
| |
Not a bad idea, but the amount of power you gained from the bearings woul quickly be eat up powering the electro magnets. There are non-electro magnets that would be powerful enough to hold the crankshaft into place (rare earth magnets) but they are expensive, heavy, and would realign the magnetic poles due to the constant spinning in in one direction. Jet engines use air bearings, but i cant say as i know how they work. Roller bearings are far superior to bearing inserts. Among the many advantages of roller bearings is the fact that you dont have to use oil with roller bearings. The motor that smokey yunik built still ran oil in the crankcase. When the crank hits the oil at 5000 rpm it's like hitting a brick wall, like doing a belly flop off the tall diving board. That's what eats up the power. |
|
| |
Electromagnetic engine bearings?
I heard a good analogy for this the other day...
it is like buying a 747 for the peanuts. |
|
| |
the amount of energy it would take to run electromagnets powerfull enough to hold the vital engine parts would easily waste any gained horsepower... not to mention make designers eliminate all magnetic switches withen 15 feet. plus think about the interference in the radio. |
|
| |
Magnets aren't free of friction. There's flux leakage, eddy
currents, magnetisation, etc to worry about. |
|
| |
Improving the lubricating properties of oil would yield faster results, cheaper. If you want good results, now, use Castrol Syntek, Mobil 1, or Slick 50. Install an auxiliary electric oil pump to lubricate the bearings at start-up, so you have full oil pressure before the engine turns over. Buy an electric heated dipstick to heat the oil for a couple hours before you drive off. Where are those fluoridated Buckyballs we were promised a few years ago? |
|
| |
magnetic bearings in a piston engine would be too complicated and inefficient, magnetic bearings in turbines are awesome (i use them in the turbines i make that have power outputs above ~400 kW , below this power regular oil bearings are more cost-effective - although the friction does cause parasitic losses - about 2-5% depending on application) and magnetic bearings are a must in any application where the oil will be destroyed by the fuel itself (corrosive fuels - mainly acids and bases) |
|
| |
magnetic bearings consume less power than their oil bearing counterparts in turbines. you should probably read up on magnetic bearings before you comment about them |
|
| |
roller bearings are not superior as you have to cool them and this destroys the effectiveness of the turbine as it is a heat engine and providing cooling in the wrong place works against the engine itself as the turbine's efficiency is dictated by how high the high temp side is and low of the low temp side. same thing with the air bearings but this time it's pressure in the wrong place as a turbine's efficiency is also determined by the pressure drop across the blades |
|
| |
the newest thing on magnetic engine bearings is magnetic monopoles via the halbach method [link] |
|
| |
the idea is that using these magnetic monopole forms on the electric motors of flying vehicles skips the weighty iron part |
|
| |
translation: you are right |
|
| |
//Among the many advantages of roller bearings is the fact that you dont have to use oil with roller bearings// |
|
| |
... really? What the hell kind of roller bearings are you using? Do they last long? |
|
| |