Tire Heat

[Jersey Tom]

Maybe a strange question, but does the steering angle influence the accuracy of the temperature readings on the front wheels? There are some obvious changes during steering, but I was wondering if part is due to the camera (to prevent wrong conclusions).

That's a good question. I wouldn't think so though, not the angle bit anyway.

I would however be extremely careful from drawing conclusions from IR data in general.

[Blanchimont]

I think you have to be very careful with these images, as with all thermal cameras.

The surface (material, colour) of an object influences the infrared radiation. That means that two objects with the same temperature can show different temperatures when being analysed with an thermal camera.
And the radiation can also be reflected by other surfaces as can be seen on the nose.

I wonder why the inner and outer tyre walls show that little heat, is it because of the calibration of the temp range or because of the angle to the camera, as Tomba suggested?

For me it seems to be logical that the angle changes the energy that reaches the camera sensor and therefore the displayed temperature should also change.

[marcush.]

Maybe a strange question, but does the steering angle influence the accuracy of the temperature readings on the front wheels? There are some obvious changes during steering, but I was wondering if part is due to the camera (to prevent wrong conclusions).

That's a good question. I wouldn't think so though, not the angle bit anyway.

I would however be extremely careful from drawing conclusions from IR data in general.

I would however be extremely careful from drawing conclusions from any data in general .....

I´d say the tyre surface is not the worst place to take IR readings with confidence .You need to correlate your measurement ,your test setup must be checked and verified of course and you heck you need to prove your findings by using a different measuring method to be absolutely sure you are measuring no silly things ...normal testing proceedures that is .
IR thermal imaging is a proven method and it beats discrete sensors or IR only sensors giving you a moving picture of what is happening in reality ....I would almost go as far as giving the driver an IR view in his helmet...just imagine you canactually see your own and the competitors tyre temperature situation... and can push him harder in those areas wwhere he hurts the tyres already....great unfair advantage...

[raymondu999]

Maybe a strange question, but does the steering angle influence the accuracy of the temperature readings on the front wheels? There are some obvious changes during steering, but I was wondering if part is due to the camera (to prevent wrong conclusions).

That's a good question. I wouldn't think so though, not the angle bit anyway.

I would however be extremely careful from drawing conclusions from IR data in general.

Tomba, are you thinking along the lines of Doppler effect? It could explain the sudden spike of red when the car starts turning

[marcush.]

the camera sensors reaction time is short enough to not have any "phantom" effects , obviously highly reflective/shiny surfaces lead to problems ,but these should not be present with the tyre surface.

With the sudden changes - you could adapt the image generation to start only at 89.0°C so when the tyre reaches this threshole you would sudenly see color developing ...let´s assume you got 160 steps in color available but end your range of display say at 115°C-You would also have 160 distinct color shades to cover a range of 25degrees....that´s a new color for every .2° of temperature change .....the pictures would lead you to think temperature is changing rather quickly even though in Reality the temperature gradient is rather flat....
Perception can be very misleading..

[strad]

well what I found interesting was that on the warm up lap that the tires even though fresh from the blankets register black and we know that the blankets keep them so hot you don't want to handle them without gloves, so the first color gradient must be above that temp, which is what 160-180 degrees F ?

[raymondu999]

Yes I think they moved the scale aggressively upwards (so that only extremely hot temps register) so that the colour change is more easily perceptible

[aussiegman]

There are some interesting observations watching Di Resta's and Maldonado's laps and especially Di Resta's lock up:

You can see the tyre's heat rise as soon as the brakes are applied, but there is no temp indication from the brakes or the air venting off them (same as the radiator). With the if the brakes are running at such high temps you woudl expect there to be some heat "bleed" that would show up in the 95-135 degree c range.

You can see the hot spots from the lock up on the tyre face as well as the camber running line but there is nothing during the warm up as said and no heat from the brakes again

You can see the heat on the tarmac as a he leaves the rubber from the lock up and then again when the tyre bounces on the road as he heads in to the wilderness

The cars in front of Di Resta show significantly different tyre temps front (black/purple) to rear (red to orange) prior to the crash.

[marcush.]

A FLIR GF-Series infrared camera detects an underground natural gas pipeline leak.

http://bcove.me/vo2ieh3d

so the infrared camera can detect the hot air coming from the brakes the question would be why is the thermal imaging in the pdr video not at least showing a little bit of colour when the hot air is cooling down to something close to the tyre temperature?

[hollus]

The camera only pick us IR intensity. With air being so much less dense than tires it would have to be much hotter to produce a comparable amount of IR light. I am having trouble finding an emissivity value for air as it is not a surface, but the fact that you see through it in those IR wavelenghts probably means a value very close to 0, as emission and absorption are often follow similar trends.

[olefud]

A FLIR GF-Series infrared camera detects an underground natural gas pipeline leak.

http://bcove.me/vo2ieh3d

so the infrared camera can detect the hot air coming from the brakes the question would be why is the thermal imaging in the pdr video not at least showing a little bit of colour when the hot air is cooling down to something close to the tyre temperature?

I think the film is not showing the natural gas per se but is showing the background IR being blocked by the methane. Methane is a known climate warming gas and thus absorbs longer wavelengths.

[marcush.]

the atmosphere has an emmissivity of around 0,81(average) so the error against a standardised black /grey emitter at 0,9 to 1 is present but not as severe as a shiny metal surface which has a emissivity of .05 !

The main contributor to emissivity in atmosphere is water vapor (around 0,66) so you need to know moisture content of the air you are looking at as it is really the main variable ....

[hollus]

How is that 0.81 defined? For what thickness or amount of air?

[olefud]

the atmosphere has an emmissivity of around 0,81(average) so the error against a standardised black /grey emitter at 0,9 to 1 is present but not as severe as a shiny metal surface which has a emissivity of .05 !

The main contributor to emissivity in atmosphere is water vapor (around 0,66) so you need to know moisture content of the air you are looking at as it is really the main variable ....

Atmospheric emissivity is a little tricky. Emissivity is based on an infinitely thick dimension –or until the emitting material become opaque. The atmosphere is neither infinitely thick nor opaque. So the .81 is through the entire typical atmosphere.

Since N2 and O2 have zero emissivity, the average concentrations of H2O vapor, CO2, CH4 and O3 ¬ -the principle emitting gases in air- are used for the .81 figure. Surface troposphere air is typically different from the atmosphere as a whole.

[stez90]

I think those picture are way off, only for entertaining purpose.
Compare other thermocam images, the show very small gradients.