Hotest/coolest spots in automotive environments

What brand of car? I always muse every new model year the number of new Mercedes and GM vehicles DOA on the side of the road.

The National Weather Service in Phoenix has issued an "extreme heat advisory". Out here in San Tan Valley the weather report is "seasonably warm" ;-)

The US has become a bunch of wusses.

Under a front driver's seat or left kick panel is where most engine controllers go. ...Jim Thompson

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| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142     Skype: skypeanalog  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

If the vehicle is black, parked in the middle of a black parking lot, in the middle of Arizona in the middle of summer, with little or no wind, the ambients can just keep stacking up and up. A dark metallic shifter in the middle of a black car (including black interior) might well get hotter than the engine in operation -- it has the benefit of moving air and water!

Down below or underneath, away from direct sunlight and convection (but inside of any environmental hazards -- sealed inside a door or body panel, or beneath a head light?), would seem like the best place.

Obviously, you don't want to go too far "down"; the exhaust system will be considerably hotter than either, in operation. :)

And it can get even worse than that, if you park in a solar farm:

Tim

--
Seven Transistor Labs, LLC 
Electrical Engineering Consultation and Contract Design 
Website: http://seventransistorlabs.com

But is that because it is the most environmentally hospitable? Or, because it is the most *convenient* (for access, wiring, etc.)?

E.g., if you never needed to access a device, where would you position it?

Does it matter? It's going to plug into a harness. In AZ you're not

that's easy.

...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142     Skype: skypeanalog  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

I think the tougher problem is addressing a *parked* vehicle. I.e., a vehicle in operation must be (reasonably) habitable to humans, can employ active cooling means (even if just "forced air"), etc.

I was considering this especially in light of the fact that the vehicle in question was sitting on an unshaded dealer's lot, day in, day out...

[At least it drops down to ~80-ish at night -- I wonder what the *net* temperature (for something with a long thermal time constant) is?]

The exterior will conduct heat (hmmm.... maybe some of these plastics and composites are less problematic than old-fashioned steel?) to the chamber it encloses.

Likewise, heat radiating off the road surface (which wouldn't be "shaded" if the vehicle was in motion).

A neighbor (computer tech) had some aerosol product explode while it sat in his parked car "on a call". We, long ago, learned to carry a cooler with us when purchasing groceries, fetching DVD's from the local library, buying medicines, etc. It doesn't take long for the car interior to become very inhospitable to most things!

In a dark coloured box on the dash or rear shelf.

I used to have to unplug the blinker unit in my Citroen CX and stash it under the seat when parking, the capacitor was only rated to 105 degrees centigrde, and on a sunny queensland day it would exceed that in the spot where it plugged in,

under the seats, behind, or in, the centre console

--
umop apisdn

High up in the passenger cabin is a good place for high temperatures. Just where electret microphones for hands-free mobile phone systems are often placed. Depolarisation of the electret film is a potential issue.

John

no particularly convenient, on the firewall (either side) would be easier to wire. it's only conveiwnce of assembly that counts.

if _never_ Inside the air-con radiator.

if more than never, under the carpet, under a seat.

--
umop apisdn

White would cause reflections in the windshield. Although white is better than black locally for reflecting sunlight away it isn't that much better when the entire of the car interior is mad hot.

But they seldom get above 80C so most *decent* electronics should be fine. Unless you park unwisely at the focus of a mirror sided building:

Since many car components are thermoplastic life gets fun if they get to the point where they will permanently deform or warp.

Seems very surprising. Most electronics is good to 100C or so - much above that and capacitor electrolytes tend to escape over time. But that wouldn't account for immediate acute failures. Bad design perhaps?

I can't believe self heating is a problem in automotive CCD cameras.

--
Regards, 
Martin Brown

Of course. It also would make the device more noticeable to the vehicle occupants and passersby. Much like the reason rear glass is often "painted" black around the edges (instead of "body color")

I'm wondering if trying to make the box and its internals "invisible" allows it to absorb more radiation than the car interior. E.g., a black interior tends to be hotter than a light colored interior...

Dunno. The salesman's casual response suggests it happens often. Hard to believe the manufacturer would overlook something as basic as this at design time. Nor fail to notice it post-production.

OTOH, were I designing for that sort of a placement, I'd be hard-pressed to come up with a priori parameters to accurately reflect what a "glass mounted, black box" would experience in high ambient and prolonged, intense sunlight (hence this question, here).

Unless the component itself wasn't specified for an automotive environment? E.g., component mixup at time of manufacture (I once had a 2'x 6' ECL memory panel delivered with the wrong voltage specifications on the bypass capacitors; LOTS of rework, there! :< )

Note I have no idea *what* is failing in all of these complaining "features". The *obvious* thing that they all have in common is this camera module. They all rely on the camera to sense the locations of "things" that the vehicle is approaching.

But, they may also have additional kit hidden away, elsewhere, that is actually the source of the fault.

So, the location of this particular type of camera module. Likewise, HUD's? Would "sealing" it *to* the glass be any worse than setting something *on* the dash?

I should explore where they site the batteries in the hybrids as that would probably NOT want to be an inhospitable location. OTOH, their sheer size may so severely limit the options...

Unrelated to heat, But I want a camera on a pop-up periscope, above my small car so that I can see over the SUV's and trucks in front of me and not have to just adjust my speed according to their brake lights.

It would also be very useful in the winter (around here.) So you could see over high snow banks before pulling into an intersection.

George H.

What's a "snow bank"? Is that where you go to deposit your snow ?>:-} ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142     Skype: skypeanalog  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

rake lights.

ee

Grin, this last winter we didn't get a thaw and the snow banks were ~6' hig h. You are basically driving in a tunnel. At intersections your only option i s just to pull out slowly and hope that any drivers coming along the other way are going slow enough and see the front of your car pulling out. By th e time you can see if there are any cars you are blocking ~1/2 of the lane.

A scarier thing is when you are driving through a village or something with young kids. They can "pop out" of their drive way (on a sled or somet hing.) with no warning.

George H.

brake lights.

see

igh.

is just to pull out slowly and hope that any drivers coming along the othe r way are going slow enough and see the front of your car pulling out. By the time you can see if there are any cars you are blocking ~1/2 of the lan e.

some of the fancier BWMs have side view cameras in the front bumper so you can see "around corners"

-Lasse

I know. I grew up in WV and schooled in MA... that's why I live in AZ ;-)

[snip]

I once slid sideways for half a block down a WV hill, narrow street, cars parked on both sides, black ice... how I missed all those cars I'll never know... heart stopped for 10 seconds :-( ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142     Skype: skypeanalog  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

ir brake lights.

ld see

}

high.

on is just to pull out slowly and hope that any drivers coming along the ot her way are going slow enough and see the front of your car pulling out. B y the time you can see if there are any cars you are blocking ~1/2 of the l ane.

u can see "around corners"

That would work for intersections. I still want a camera on a pole for when I'm driving down the highway surrounded by monstrous SUV's and pick-up trucks. You probably don't have the problem in Denmark. (Is Denmark correct? I googled you, Nanonord? Hey are you also doing NMR with permanent magnets? or the XRF stuff?)

George H.

I suspect that the camera is made out of a bunch of consumer-grade parts, and that the black case, behind glass, in the sun, is getting toasty inside.

It may work better when you're on the road and air is flowing; it may not.

The best thing to do is design a new camera from the ground up, including the chips.

The second-best thing to do is to take the case and paint it white or very light gray (I'm sure there are at least fifty shades to choose from). That would significantly reduce solar loading.

Or, learn how to drive so you don't need a robot helping you!

--

Tim Wescott 
Wescott Design Services 
http://www.wescottdesign.com

That's what has prompted the car search: too many trucks (that never are *used* as trucks... just "Hey, look at my MANLINESS! (Change the oil? How do you do *that*??)" SWMBO is tired of feeling "lost in a sea of steel". Esp given the number of lousy drivers, here (esp the "winter visitors"/old fartes)

Likewise, pulling out (or backing out) of a parking spot between two soccer-mom-obiles would be greatly facilitated!

[Actually, the backup cameras on some vehicles have a wide-angle mode so you can peek off to the sides as you ease out. And, a feature whereby the vehicle reports oncoming "traffic" from either side before you've got your ass-end sticking out into it. But, I'm not too keen on looking forward (into a display) to *see* backwards! OTOH, it appears as folks age the ability to turn their head diminishes. I guess I'm not old enough for that as looking over my shoulder is still entirely natural...]

Or, seeing beyond that car in the *opposing* "left turn lane" so you can sort out when it is appropriate to "turn left across traffic".

[(sigh) I miss snow. And *good* apples! I've been lobbying to move to someplace like Washington state -- or Scandinavia -- though I think I'd quickly tire of overcast days, rain, etc. "360 days of sunshine" really does become noticeable -- esp when you find yourself (temporarily) elsewhere dealing with "yet another dreary day"! OTOH, it is *really* easy to lose track of days, weeks, months, even *years* when you lose many of the seasonal cues.]