Tire Temperature Sensors

[kmrobinson]

Hi, I did a search but only turned up some fairly old information.

Does anyone know of a non-contact type of temperature sensor that isn't a thermocouple? Our DAQ system doesn't support anything except voltage inputs, and therefore all the nice, relatively inexpensive IR thermocouples are rather out of the question.

I've seen some tire temperature sensors on websites, but there are no brands, prices, or operating principles listed. Any help would be greatly appreciated.

[Charlie]

Originally posted by kmrobinson:
Our DAQ system doesn't support anything except voltage inputs, and therefore all the nice, relatively inexpensive IR thermocouples are rather out of the question.


Out of the question? Why?

[js10coastr]

OMEGA has some for around $100 each, although they are a bit on the large size.

[J. Vinella]

http://www.solidstateracing.com/

Has some smaller ones that are listed as $180, but it never hurts to ask for a better deal.

[Jonathan S]

We have used the IR sensors from SSR. You may want to keep in mind how fast the sensors respond. The ones from SSR update at 2Hz, you may find you want sensors that are faster than that.

[murpia]

Originally posted by kmrobinson:
Our DAQ system doesn't support anything except voltage inputs, and therefore all the nice, relatively inexpensive IR thermocouples are rather out of the question.
Infra-red temperature sensors are not thermocouples. They are available with voltage outputs, so many brands will suit your DAQ system fine.

Regards, Ian

[kmrobinson]

Thanks for the replies. I'll look into those IR sensors from SSR, they might be what we're looking for. The low rate could be bad, but hopefully we can get away with that.

[VinceL]

"The low rate could be bad, but hopefully we can get away with that."

I would say that you want a faster rate than 2 Hz. Think about how fast your tire is rotating. With an IR sensor you're not looking for long term trends, but instantaneous temps in mid corner.

[Jonathan S]

I guess I should clarify... SSR's cheaper sensor has a response time of 500ms. They sell ones for a little more that have a response time of approx 50ms - but with less repeatability and sensor-to-sensor accuracy.

[Buckingham]

Our DAQ system doesn't support anything except voltage inputs

Thermocouples ARE voltage inputs. Usually +/- 80 mV will be about the full scale rating of the wire, but each wire type has its own cal curve. Just be mindful that anytime you connect a thermocouple wire to the inputs on your DAQ, you create additional thermocouple junctions.

But as previously mentioned, you should be able to easily find what you need from omega (call them, they have decent application support).

[Charlie]

Originally posted by dhaidinger:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Our DAQ system doesn't support anything except voltage inputs

Thermocouples ARE voltage inputs. </div></BLOCKQUOTE>

Exactly the point of my earlier post, which I guess was ignored.

There are such things as thermocouple amplifiers, and they are useful for a lot more things than IR tire temp sensors.

If you find a 'non-thermocouple' IR temp sensor, it IS going to be a thermocouple, just with an internal amp.

[Kurt Bilinski]

I thought IR wasn't a good idea for tire temperature monitoring due to it only seeing the surface temp. The temperature 1mm below the surface can and will be a lot different, which the pointy-type probs do pick up. Of course that's of no use if you are monitoring dynamically. In that case I don't know what alternative to IR you could use.

Thermocouples produce voltage directly, but are almost always fed through a linearizing amp and DL system. A K-type would work great.

[ben]

Originally posted by kb58:
I thought IR wasn't a good idea for tire temperature monitoring due to it only seeing the surface temp. The temperature 1mm below the surface can and will be a lot different, which the pointy-type probs do pick up. Of course that's of no use if you are monitoring dynamically. In that case I don't know what alternative to IR you could use.

Thermocouples produce voltage directly, but are almost always fed through a linearizing amp and DL system. A K-type would work great.

Surface temperature's not worth measuring in the pits because it changes incredibly fast. Measuring it on board is very useful though.

Looking at the min, max and average surface temp can tell you a lot. You need heat on the surface of the tyre to generate grip, but a lack of grip can also generate heat due to excessive sliding. Generally speaking if you have high peak temperatures and low minimum and/or averages this is a good indication that the tyre's just letting go. It's normal for a qualifying tyre to show higher minimum and average temps but lower maximums because it's hooked up better.

Due to the variation in compounds and track surfaces around you really need to get a feel for how your tyres behave and what sort of surface temps correspond to good grip levels.

This is not to say that you shouldn't use a needle probe in the pits - you should because internal temperature generation due to shear deformation of the tread is another factor on top of the surface temp. In simple terms, the bulk temp will influence the indentation (mechanical grip) of the compound, whereas the surface temp will relate more to adhesive grip mechanisms.

Ben

[kmrobinson]

So what I'm getting is a standard DAQ system that's used to a 0-5V analog input should work with something like the Omega OS36-01 (http://www.omega.com/pptst/OS36-01.html)? I always read that thermocouples required the linearization/amplification equipment to generate enough signal. Another important factor is cost. Buying a ton of expensive sensors isn't going to make the car sufficiently faster to justify the expense.

Addendum: What about these needle probes? We've always done our tire temperatures in the pits, which seem to be reasonable indicators, but we'd kill for more data as to tire temperature vs. performance.

[Charlie]

It's really simple. Like I said above, thermocouples require amplifiers to (accurately) work with 0-5V DAQ systems. But that's all they require, and thermocouples w/amp are a pretty typically used component in DAQ.

Should you buy a bunch of thermocouple IR sensors? I don't know, because I don't know your budget. But, you should definitely have on hand some thermocouple amplifiers for your DAQ system. Because they expand your DAQ ability so much. Thermocouples are generally inexpensive and can be found in so many different configurations, and used so many different ways.

If price is an issue, you can always make your own amps (http://www.sparkfun.com/commerce/product_info.php?products_id=306)

[murpia]

Originally posted by kmrobinson:
So what I'm getting is a standard DAQ system that's used to a 0-5V analog input should work with something like the Omega OS36-01 (http://www.omega.com/pptst/OS36-01.html)? I always read that thermocouples required the linearization/amplification equipment to generate enough signal. Another important factor is cost. Buying a ton of expensive sensors isn't going to make the car sufficiently faster to justify the expense.
OK, those Omega sensors are jumping through the hoop of an analogue voltage sensor SIMULATING a thermocouple output so they can be used to replace a thermocouple in a data system. Probably useful in an industrial situation.

Try these (http://www.omega.com/ppt/pptsc.asp?ref=OS136) instead.

Regards, Ian

[murpia]

Originally posted by ben:
This is not to say that you shouldn't use a needle probe in the pits - you should because internal temperature generation due to shear deformation of the tread is another factor on top of the surface temp. In simple terms, the bulk temp will influence the indentation (mechanical grip) of the compound, whereas the surface temp will relate more to adhesive grip mechanisms.
Hi Ben,

I was wondering how much the bulk (needle probe) temeprature might affect the compound hysteresis? Is this a significant factor in the mechanical grip of the tyre?

Regards, Ian

[ben]

Hi Ian. This is still an area where we're still working empirically. Mathematical modelling of different tread compounds is not exactly scientific yet.

The bulk temperature primarily affects indentation. We have had situations where different materials cause the rubber to be very hard at low temperatures but soften significantly at higher temperature. They can give you advantages in terms of being stronger for a given hardness at high temps with the trade-off being high hardness at low (or bulk) temps.

On rough surfaces you can run into trouble if the the bulk temp doesn't reach a high enough level you can lose a degree of indentation which the rider can feel as aggresive sliding or a vagueness.

Like I said this sort of thing depends on the type of compound you have. Things like the Avon compound appear to use a lot of oil and are very soft at room temperature. I suspect the window for this compound is wider because the modulus doesn't change as much with temperature - this would be more characteristic of a qualifier for us.

More modern compounds such as that used by Pirelli with Darmstadt appear much harder at room temp but soften off with temperature - it's these types of compounds that are going to be more sensitive to the bulk temperature you achieve. The affect will be amplified the rougher the track surface is.

Ben

[kmrobinson]

Originally posted by murpia:
OK, those Omega sensors are jumping through the hoop of an analogue voltage sensor SIMULATING a thermocouple output so they can be used to replace a thermocouple in a data system. Probably useful in an industrial situation.

Try these (http://www.omega.com/ppt/pptsc.asp?ref=OS136) instead.

Regards, Ian

Those might be what I'm looking for.

Thanks everyone for the incredibly informative responses, I'm learning quite a bit!

[Matthijs]

Currently we are also trying to measure tyre temperature by means of IR temperature sensors. A search on the internet provided us several IR sensors, among others the Omega OS136 series. The sensor of SolidStateRacing (G2 pro) also looks promising. We're not sure which one we should choose.

It's been almost a year ago since this topic was started, so i am wondering what results are made so far. Are there teams/people here who worked with one of these sensors? If so, how did they perform? Or which sensor do you recommend in stead of the OS136 or SSR G2 pro?

Matthijs
University Racing Eindhoven

[Damon Pipenberg]

We've used the Omega OS136s and they work extremely well, however they are somewhat large and heavy. That means that you need a fairly substantial bracket to cantilever them over your tires. The SolidStateRacing sensors might lighter and easier to mount.

[BillCobb]

Why not consider a 4 view home security system with 4 split screens and 4 IR night vision cameras? Do you need absolute temps or temp uniformity? IR cameras show temp distribution very well. If you are broke, get to a junkyard and rescue the IR night vision cameras fom Cadillac DeVills. They are monocolor but serve the purpose (for examining the effect of pressure and camber settings) for example. If you just use 1 thermocouple, you will probably miss the edge, center, bead, or crown temperatures IMHO.

[Matthijs]

We need absolute temperatures of each tyre at the inside, centre and outside. In all we need 12 + 1 (reference temp) sensors. Our budget is not that high, so the sensors from Omega or SSR are preferable. Finding four Cadillac deVilles at a yunkyard is nearly impossible in the Netherlands, you'll only find crappy VW Golfs or old French cars http://fsae.com/groupee_common/emoticons/icon_smile.gif. Omega has an office in the Netherlands, we're going to contact them.

Thanks for the reply so far.

Matthijs

[brettd]

Did anyone else see the ones on Helsinki's car this year? Looked very tidy.

[HenningO]

www.optris.com (http://www.optris.com)

We got sponsored with 12 pcs works really well. Very durable yet small.

[TMichaels]

Hey Guys,
has nobody faced problems with changing tyre surfaces changing the measured temperatures? Since the IR-Sensors work with a predefined emissivity and the emissivity changes with the surface a graining tyre may give complete different readings than a normal worn tyre for example. What are your experiences with that? We noticed big changes in the measured temperatures by only comparing a new unused tyre surface temperature with a used one at room temperature in our shop.

Regards,

Tobi

[exFSAE]

So long as its more or less consistent across the tread I wouldn't worry. The absolute magnitude of temperature isn't the big concern with IR.. it's the spread.

[Momchil]

I have a question, because with the L shaped bracket last year there are a lot of vibrations in the sensors and they dont measure well, so can anyone of you have a solution about how can I mount the sensors to the upright
Thank you

[Boffin]

Originally posted by Momchil:
I have a question, because with the L shaped bracket last year there are a lot of vibrations in the sensors and they dont measure well, so can anyone of you have a solution about how can I mount the sensors to the upright
Thank you How have you mounted them currently? I assume that you have mounted vertically in relation to the tyre (dead above).

From my experience having tried the above method (vertically above the tire), I had someone mount them off the top clevis mounts on the upright, using plate to make an oversized camber shim, then having 25mm RHS welded to this. What happened though was that to clear the A-arm to upright clevis bolt, either the RHS had a notch taken out or the top edge of the RHS at the mount was chamfered to clear the rim. Needless to say compliance was on issue, and it resonated like a guitar string.

When I remade these for Japan testing, on the front I kept the oversized camber shim but passed 12mm x 30mm RHS either side of the A-arm to clevis bolt, mitered the other end of the 12x30 RHS and then continued using the 25 RHS tube like before. This greatly improved the welded area at the upright, and also between the rectangle tube and the square tube. This solution was incredibly stiff.
On the rear however, I mounted off the jacking bar and ran a tube out to the tyres. Not ideal as the above as the distance to the tyre changed with suspension travel but it was very quick to make.
I’ve scoured some photo’s and this is the best I could find

http://sphotos-a.xx.fbcdn.net/hphotos-frc1/295590_10150267473408277_8178894_n.jpg

http://sphotos-a.xx.fbcdn.net/hphotos-frc3/293912_10150267473768277_5253826_n.jpg

http://sphotos-a.xx.fbcdn.net/hphotos-frc3/293673_10150267475208277_6501926_n.jpg

Hope this helps a bit.

[Claude Rouelle]

I suggest you contact Pierre-Alain Aucouturier pa.aucouturier@texense.com from Texense in Indianapolis, IN. Pierre-Alain is French but he speaks and write perfect English.

Texense is French company which was born from former Prost Formula One team.

They have sensors in every single race car category in the world

I have been working with Texense for 12 years and I only have positive recommendations.

I know they do very special deals for students involved in FS / FSAE.

If I remember well Pierre -Alain told me he will attend FSAE in Michigan

[Techmor_Inc]

Techmor, based out of Cornelius, North Carolina offers a CAN output IR tire temperature sensor and distributes through Kaztechnologies. The low profile sensor has a PEEK enclosure to reduce thermal effects and has 20 Hz update rate. Get more info at the link below or go to Techmor.com.

http://www.kaztechnologies.com/fsae/tire-temperature-measurement-kit/