Thermography: A New Weapon in the NASCAR Arsenal

What’s Wrong With this Cow?

Can you tell?

If you said the cow is the wrong color, you’re close. But there’s more to the story.

And What’s That Got to Do with NASCAR?

Competition in NASCAR is getting tighter and tighter. As NASCAR’s ramped up penalties for rulebook violations and started encumbering wins, teams are looking for other ways to gain an advantage. Some are trying ‘big data’: gathering every bit of statistical data they can about different races and trying to find patterns that will allow them to predict the best course of action in a given circumstance. Some have instituted detailed inventory programs that track how long every part on the car has been used.

Others are just looking for a new way to ‘see’ things.

What and How We ‘See’

But the way most people thing of ‘seeing’ is very limited. Human eyes are engineered to detect a very narrow range of electromagnetic radiation. We don’t call it electromagnetic radiation: We just call it light.

 

What we see as white light is made up of light of all different colors. You can see this by passing light through a prism. Red light is refracted less than the violet light, so the colors separate.

 

They behave differently because different colors of light have different wavelengths; Red light has a bigger wavelength than violet light. Violet light is around 400 nanometers in wavelength. (A nanometer is a millionth of a meter). Red light is around 700 nanometers in wavelength.

You might be thinking ‘wow – I can see light from 400 nanometers to 700 nanometers. That’s pretty impressive.

Actually, it’s not because electromagnetic radiation comes in a huge, huge range of wavelengths.

A note about the graph below.

Each tick mark is a factor of 10. So the wavelength of electromagnetic radiation we know about goes from 0.001 nanometers (gamma rays) all the way up to 1,000,000,000,000,000 nanometers (which is 1,000,000 meters or 1,000 kilometers).

The microwaves in your oven have a wavelength of about 12 centimeters. That’s absolutely HUGE compared to visible light, which is why you can’t see microwaves.

X-rays, on the other hand, range from a hundredth to 10 nanometers. This is so much smaller than visible light that we can’t see them, either.

In fact, we don’t see much of the world with our eyes.

But, being resourceful humans, we figured out how to ‘see’ using other wavelengths.

We developed radar (which has wavelengths in the centimeter range) to detect incoming airplanes long before they were visible to the eye.

We use radio wave telescopes for astronomy.

We use ultraviolet waves at crime scenes to detect blood and urine. And other things.

The Magic of Infrared

Infrared radiation is just to the right of the visible spectrum on the diagram above. “Infra” mean larger than; infrared radiation has a larger wavelength than red light: from about 800 nanometers to 1000 nanometers (which is 1 millimeter).

We can’t see infrared radiation with our eyes, but we feel it as heat. About half the energy the Sun puts out arrives not as visible light, but as heat.

You and I emit infrared radiation. In fact, that’s how the found the Boston Marathon bombers: they detected their heat signatures.

Anything hot emits infrared radiation. And therein lies the utility. Even a plane invisible to radar is emitting heat.

The first thermographic cameras were developed for military use. They use semiconductors, which are sensitive to infrared radiation wavelengths. At first, these cameras were very noisy. They had to be cooled to liquid nitrogen temperatures (or lower) to work with any precision and the pictures were still very blurry.

We improved the semiconductors and got them to the point where they didn’t have to be cooled to work well. By the 1990s, the cost had come down to the point where they were affordable and compact enough for non-military uses.

In fact, you can buy an attachment for your phone to turn it into an infrared camera for a couple hundred dollars.

Depending on how much money you have to spend, you can get cameras with much higher quality, frame rates and precision. FLIR is the leading player in the market and, in fact, even sponsored Jamie McMurray a couple years ago.

How Thermography is Useful for Motorsports

An infrared camera is a great toy, but motorsports has found a lot of uses that might give the smart team a big advantage on track.

IMPORTANT: The colors you see on thermographic images are all made up. Basically, the sensors detect the wavelength of the light (which is invisible to our eyes) and assign a color scale to the temperatures to make it easier for humans to interpret the date. This is done in warm colors, but there’s no reason you couldn’t do it in blues or greens.

Finding the Best Line

Last week in New Hampshire, one of the television commentators finally mentioned that teams are using infrared imaging to try to help their drivers determine the best line. How do you do that? Take a look at the video below, which shows the heat trail from cars on an expressway in Germany.

Notice how the pavement heats up after the car passes? Imagine how the pavement heats up when there are 40 stock cars passing over it almost continuously. Thermography tells you the track temperature.  You can see the trail of the tires in the pavement during the burnout in the video above.

This is especially useful at a track like New Hampshire, which treated the asphalt surface with VHT before the race. Teams have a lot of questions about VHT, especially about how it wears. It seems to last for a very long time at some tracks, and wears off in the middle of the race at others. We know that track temperature is a Goldilocks thing: it can’t be too cool and it can’t be to hot. By using a thermal imaging camera, a team can tell which areas of the track are getting too hot, or which areas might be too cold.

If you listen into a scanner and hear a crew chief or spotter telling a driver to ‘try taking the lower line’, but they don’t say it’s because another car is having success there, chance are someone has been studying the track with an IR camera and thinks they’ve found a good line in terms of track temperature.

Repaving

One of the critical factors that determines whether a piece of asphalt is going to retain its integrity is the temperature of the mix as it’s being lain down. A number of companies are now using infrared imaging to ensure that there aren’t hot or cool spots as the asphalt is being laid that could later turn out to be problem areas. This is being done on commercial roads, and being heavily used for testing of new asphalt mixtures.

The picture at right shows you the false color scale. You can see that they’ve used cool colors for the low temperature and red for the warmest temperature. The cool area in the middle suggests that there may be air gaps or some other inhomogeneity that could cause problems later.

Oil Spills

NASCAR itself has been using IR imaging for a few years now to spot things on the track. Track temperature is often around 130 degrees F; the oil inside a car is much hotter, so when a car dumps oil on the track, you might not be able to tell with your eyes, but an infrared camera will see it. The more sensitive the camera, the better it works because oil will cool as it spreads across the track. A cheap camera might not be able to distinguish between the oil spill and the track. (FLIR is also using their cameras to detect oil spills in water, too, as a way of monitoring and helping clean up if there is an oil spill.)

Tires

Take a look at how, in real time, the tires on this F1 car change temperature during cornering.

Right now in NASCAR, teams use a temperature probe to measure the tire temperature in three or four spots after they’ve been removed from the car. There’s nothing in the rules that would prohibit them from just taking infrared pictures of the tires. That might not be useful data during the race, but it could be analyzed afterward.

Brake Rotors

One of the big challenges at places like Bristol and Martinsville is the huge amount of heat generated by the brakes. The friction of brake pad on rotor creates a lot of thermal energy. A high-speed infrared camera (and when we’re talking high-speed, now we’re starting to get up into the $$$$ range) can capture brake temperatures while the car is on track.

IR imaging is already being used by brake pad and rotor manufacturers to test their new designs. You could imagine NASCAR teams using a tool like this during development to study how slight changes in the cooling duct arrangement affect brake rotor temperatures, or to compare different combinations of pads and rotors.

The Future of IR Imaging in NASCAR

It’s only going to get bigger. You’re talking less than $10K for a decent IR imager and maybe $40,000 for a really nice, high-speed “science-level” InSb sensor camera. That’s small potatoes for a top-level NASCAR team. Engine development companies are also using this technology to study combustion details and heat management in the engine system. Cooling efficiencies in the radiator and the oil lines can be studied with infrared imaging.

I can also imagine the slap-happy engineering staff finding some, uh… less car-related uses for the equipment.

Wait! What About the Cow?

I almost forgot.

Veterinarians use thermal imaging of animals because they can learn something from the thermal signature of an animal. Just like you and me, animals get hot when they’re not feeling well. In this case, the telltale sign in that the cow’s hoofs are warm. They shouldn’t be. What you’re looking at is a potentially sick cow.

Don’t laugh. When you’ve got a large herd of animals, disease can travel quickly, so identifying potentially ailing members of the herd quickly and getting them treatment is critical.

Plus, there are currently test programs to use thermal imaging at airports when there’s an outbreak of a disease like Ebola. The earliest sign of infection is a fever, so thermal imaging could be used to identify people who might warrant further testing.

 

 


Also published on Medium.

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