Active grill block idea
 

What do you guys think about this automatic vent?
Link for more infoFind Black Plastic Auto Foundation Vent and other Home Ventilation at Aubuchon Hardware
http://media.mydoitbest.com/imagereq...=C&newsize=600

It works with a bimetal coil. That thing probably isn't strong enough to have the vent open/close at highway air pressure. It looks interesting though and could be a good base to use with a step motor in place of the coil.

That wire mesh looks about like common window screen.
It might not work real well at highway speeds, due to surface turbulence on the mesh, slowing the air flow.
If it is indeed a small mesh, you could get an idea of how it might work by driving 65 mph while holding an 8"x16" screen (on a frame) outside the window.

Interesting idea...I think I have seen something like this on semi trucks. Would be nice to have this on the cooling fan switch and only have it open when the cooling fan came on. Obviously it would have to have a motor to operate it.

justpassntime -

I'm not addressing automation, but I keep this idea floating around in my head :

Side View
http://img529.imageshack.us/img529/5...bloczk5.th.jpg

*If* you had a flat nose on your car, and *if* you had the space for a cylinder, you could have a stepper motor control a pipe that has a cutaway view that looks like the picture above. The stepper motor would rotate the pipe closed or open.

I *think* it would be robust at wind speeds.

Maybe the best way to fight the wind velocity is to have a sliding grill. Maybe a grid of holes that lines up for ventilation and slides (horizontally?) to misalign the holes, closing the vent.

CarloSW2

that's exactly what i'm planning to build

@ cfg83 your idea might work too with my setup, although it's esentially the same as what's illustrated below; bur it might work for a multi door setup where all the "rollers" can simply be connected with a single belt... i emagine cutting a slot in some plastic tubeing could look great



here's what i plan to build for my car...it'll go on the top grill but if it works successfull i might try the lower grill as well.

i'l not sure about the setup for the door yet, maybe a slider will work better, but the prinsyple remains the same.

http://i77.photobucket.com/albums/j5...hway/001-1.jpg
http://i77.photobucket.com/albums/j5...ighway/002.jpg
http://i77.photobucket.com/albums/j5...ghway/002b.jpg
http://i77.photobucket.com/albums/j5...ighway/003.jpg
http://i77.photobucket.com/albums/j5...ighway/004.jpg
http://i77.photobucket.com/albums/j5...ghway/004b.jpg
http://i77.photobucket.com/albums/j5...ighway/005.jpg

i plan to use a small motor from either an old walkman or a computer fan, the walkman motor seems to have the most torque. old toys and machines seem to be a good source for little electro motors.

the hatch itself will press on a switch at either side of its travle to indicate it's position, if the hatch should move to any position in between the motor will take it to the appropriate position again. of course mechanicly it should be set up to prevent flutter, but the system should calibrate itself.

i don't know if this will prove workable in practice but in theory i think it's pretty sound

I love the idea.

Maybe you should have some sort of delay on there, so that the door stays open for a minute or so after the fan goes off. This may prevent the system from cycling over and over gain.

that shouldn't be to difucult, with some sort of timer or even a capacitor that keeps up the right relays.

i hope i'll be able to get the mechanical part working reliable seen so i can see what the actual control needs are...


also i think the fan might already have some delay build in, wich is why i'd like to use it as a trigger rather than devise my own temperature measurement setup, useing existing car systems is more reliable and easier i think.

You might be right. The fan may already have a delay built in. I agree that it is wise to use the car's thermometer rather than hooking up your own.

Very cool

Some 20's cars had thermostatic grills that worked just like that vent. Anybody remember which ones? I thought the idea was cool, but dumb until just now; now I'm in the Awesome camp.