Magnetic slurry could deliver heatsink-as-a-service

Serious water-cooled gamer-rig types will probably get busy experimenting with iron filings, water and magnets, to see if they can maker-reproduce research that uses magnets to create what amounts to a switch-on, switch-off heatsink. In a paper co-authored by researchers from MIT and Australia's University of Newcastle, the …

[John Smith 19]

Neat.

Focused heat removal where you need it.

Although I'd presume the particles are encapsulated to prevent settling and forming a lump in the low points of the systems.

Personally I've always wondered about about a sort of "liquid crankshaft" linking the cylinders on an internal combustion engine. The system acting as a regular hydraulic system with 1 way valves to keep the pistons cycling, then turning on the magnetism to shut down part of the engine (any part of the engine) and let the rest of the cylinders run.

Handy (I though) for any big engine that runs a lot in traffic, where a lot of the time is spent on ideal.

Thumbs up for bringing this out.

[Dave 126]

Re: Neat.

Wasn't there a big American car that could, in the case of radiator damage, run on just a couple of its cylinders, and then switch to the others to avoid overheating? I seem to remember it on a Top Gear episode over ten years ago.

[Corp-Rat]

Re: Neat.

That would be the Cadillac Northstar V8 (also used in several other GM motors)

[Alan Brown]

Re: Neat.

Those limphome/fuel conomy modes shut down the cylinders by turning off fuel. Pumping losses could be drasically reduced by not opening inlet/exhaust valves but that adds mechanical complexity.

Not that it matters: The days of camshaft actutated poppet valves are numbered. Various engines (Fiat's airtronic, etc) already use hydraulics to open the valves under computer control and the camshaft is only for base timing

American-market petrol engines can't use leanburn, charge chambering or strafified mixing techniques to reduce fuel consumption thanks to federal laws which force mixtures to be stoichiometric at all times. This reduces their flexibility a lot.

[squigbobble]

Re: Neat.

The Fiat MultiAir head operates like the VAG PD diesel fuel injectors; there's still a cam lobe driving the valve but there's some hydraulics between that and valve stem which can bleed off oil from the hydraulics to control how much of the travel of the cam bucket is passed on to the valve stem. The cam profile is set up for the maximum possible lift and the hydraulics just use whatever of that is required at the time.

See http://www.greencarcongress.com/2009/03/fiat-introduces.html for a nice picture of it. It's not that distant from valves with a hydraulic lash adjuster.

The next evolutionary step is to have the valves driven directly by the hydraulics with a common rail-type set up to power them. This requires expensive valves and a very powerful pump to drive the whole lot.

[annodomini2]

Re: Neat.

@Alan Brown,

They use the VVT to keep the inlet/exhaust valves open for longer to reduce pumping losses.

[Wzrd1]

Re: Neat.

My cousin owned a Cadillac sales agency years ago.

Originally, it was an 8-6-4 engine. In six cylinder mode, it ran rough, so eventually that was dropped and it went to the 8-4 engine.

The reason it was introduced was the 1973-74 energy crisis.

[Longrod_von_Hugendong]

Re: Neat.

I also believe the current petrol V8's in the Jeep (Chrysler) cab shut down 4 cylinders when in traffic or cruising along the highway. Wish we could get them here, if i wanted a 4x4 to sound like a tractor i would buy a Land / Range rover.

[Piro]

Re: Neat.

Very interesting.

Found a great explanation of it: http://www.cadillacforums.com/forums/northstar-engines-system-technical-discussion/7027-limp-yo-self-home-n.html#post58534

[fortran]

ferrohydrodynamics

As far as I know, the general name for this kind of fluid property is ferrohydrodynamics.

I've read of some neat applications in shock dampening, and in locking seals on doors.

[The last doughnut]

Oh Em Geezus

There is another Newcastle - and it is in Australia?

I'm going, and that's all there is to it.

[Captain DaFt]

Cue the techno babble for an epic trouble ticket.

"There's been a magnetic containment breach in Server Center One!

Black Goo every where, server room temperatures dropping!

So cold... so... cold..."