Idea on Auto Adjusting Grill Block

[IamIan]

Originally Posted by Shortie771

Grabbed wht I could find around the house... Fishing line, toothpicks, cardboard, super glue and some screw (used for weights). I made a mini prototype of a version of the blind style, but I changed it.

If it turns out in practice the weights don't work as well as you would like you could also design that counter force with a spring... If the weights work good enough in practice , it might be easier to fabricate.

Originally Posted by Shortie771

Thanks for all of the info. I am still not understanding the screen style. I guess I just can't picture it for some reason.

For the basic flat plate version of the screen attached bellow are some quick crude pic I slapped together... Red and Blue indicate the different holes from the different screens... to Go from open to closed the front screen only has to move the size of the hole ... it can be designed to move vertically or horizontally.

For the 3D shaped version ... just think of a basic fixed angle blind ... mini size between the holes ... as the wind speed increased the force on that 3D surface increases the force on that front plate to move toward a favored design position ... which could be side to side or up down ... if side to side a spring or something might be needed to reset it when the high speed wind force is gone ... if it is up and down, the weight of the screen can pull it down as long as the slides are smooth enough.

The holes don't have to be circles , a variety of shapes could be used ... and the 3D surface doesn't have to be a flat fixed blind style a variety of 3D surfaces could be used.

Does this help picture it any?

As before ... the blind style can work fine... I'm not trying to convince you of any one method.

[Shortie771]

Oh, ok that makes much more sense. Thanks for the pictures. I am really liking how well this little model works when I blow on or or take a fan to it. If I blow softly, it only partially closes and a strong wind will close it completely. Just what I am trying to accomplish and regardless of how strong the wind is, it always returns to its original opened state without fail. Now I just need to find some coroplast and I can get the real thing going. When I finish it, I will strap my webcam to my bumper to create a video and adjust the weight so that it will completely close at as close to 45mph as I can manage.

P.S. fixed the duplicate photo to the correct one...

[Varn]

A lot of vehicles use a passive self adjusting system. As the pressure and velocity builds the holes in the grill create a blockage from interference drag. At highway speeds they only allow a fraction of the air through that they do with low speed.

Not sure if it is the best but think of a ford truck or car with a grill made from large wide flat plates with slots between them. The slots only allow much air at low speed.

[Shortie771]

well,I had a big cardboard box and some metal coat hangers that weren't getting any use, so I turned them into the rear weighed shutters I have been messing with. Slapped them on my car and they look and work pretty good so far. My temps stay where they should and after attaching a webcam to my car I was able to see that the shutters are opening and closing properly. The only problem that I am having is that they shutters are closing at about 25mpg, while I would rather them close around 40-45mph, but the cardboard setup cannot support the added weight

I really need to find some coroplast. I've got the itch to get this thing working, but am too cheap to go buy the stuff.

Here are some pics of how the shutters look on the car. I personally think they look pretty stylish. When I make the switch to coroplast, I will do a better job on the fitment to eliminate the gaps I currently have and I will also spray paint them black.

P.S. uploaded from phone so no license plate blocking here (you saw NOTHING!!)

[AndrzejM]

This is cool! I like the idea. Do you have a film published somewhere from the testing with a webcam. I'd love to see how it behaves when the speed increases.

[BamZipPow]

Originally Posted by Shortie771

I really need to find some coroplast. I've got the itch to get this thing working, but am too cheap to go buy the stuff.

Check with yer local sign shops fer some scraps...

[Shortie771]

Originally Posted by AndrzejM

This is cool! I like the idea. Do you have a film published somewhere from the testing with a webcam. I'd love to see how it behaves when the speed increases.

Thanks

I don't have the video anymore. I deleted it due to poor quality. My webcam isn't great and I needed to get some software on my laptop to get it to stop autofocussing every time the shutters move or I hit a slight bump. It was very laggy and at some points completely froze. I will re-attach the webcam soon and see if disabling autofocus helps. As I stated before, the cardboard can't take any additional weight. So it closes way earlier than I would like, so don't expect too much from the video.

[AndrzejM]

For me the problem is more complicated because Berta is diesel and fitted with IC. So I need to have an opening for IC for all the time, maybe it would help a bit for faster warm up with closed air duct for IC during winter, but I don't think that gain will be measureable. Anyway I want to have one opening for IC and radiator with ability to restrict air flow through radiator. See the pic. Any ideas how I could manage that with the auto shutter setup?

[Shortie771]

If I am understanding you correctly... This is the super simple solution I have come up with. Just do the exact same thing that I have going on, but cut out a hole where your IC is and put some ducting between the hole and your IC. This way you will have constant flow to your IC and everything else will open and close depending on your driving speed. I have made up a few pics to demonstrate what I'm talking about.

Hope this helps.

[AndrzejM]

That's the front view of Berta. As you can see I want to keep just the middle part of lower grille opened. So I was thinking more of some kind of blinds restricting flow through radiator (orange)