Measuring tire temperature with Infrared sensor

The measurement of tire temperatures in the racing industry is increasingly taking on a key role in tire wear management.

The window of temperatures within which a tire has maximum performance therefore maximum mechanical Grip, is becoming narrower and narrower and it is therefore critical to be able to get the tread to work within that temperature range.

Going outside the window of the optimal temperature range leads the tire to have a very fast performance collapse.

Using a precision pyrometer gives very important insights into tire management.

You can measure tire temperature using two different types of instruments:

Non-contact temperature measurement

This category includes the where the temperature measurement takes place at a certain distance from the object to be measured.

Temperature measurement with contact

Falls into this category the where the temperature measurement is made by contact between the instrument and the object to be measured.

Both solutions are accurate in terms of accuracy, it just changes the way of measurement.

With the Pyrometer with needle probe we can measure the temperature of the compound at precise points while with the Infrared Pyrometer we can choose the amplitude of the measurement, being able to measure the surface temperature of the tread.

Let us now consider how to optimize the tread temperature measurement with the Infrared Pyrometer instrument.

In this type of instrument, an electrical sensor is used that converts the infrared radiation emitted by a body having a certain temperature greater than 0 K (-273°C) into an electrical signal.

The advantages of infrared technology in tire temperature measurement are:

• reading speed;
• accuracy (+/- 0,5 °C );
• Ability to measure the average temperature of the entire tread.

In contrast, one of the main disadvantages of infrared sensor technology is that it measures the surface temperature of the tread. In fact, with this instrument it is not possible to measure the temperature of the compound, as can be done with the needle probe that penetrates inside the compound.

One of the main questions we are asked is, what is the optimal distance between the instrument and the tread to best measure the temperature?

Before answering this question, it is essential to understand the FOV (Field Of View) parameter of the IR sensor.

What is the FOV?

This is the angle within which the sensor is sensitive to the infrared radiation emitted by the object being measured.

The measured Temperature will then be equivalent to the average of all objects within the FOV.

It is essential, therefore, that the object to be measured or its portion will be completely enclosed within the FOV.

In this video, it is clearly understood how temperature measurement is developed as a function of FOV.

All models of Digital Pyrometer with Infrared Sensor from Prisma Electronics have the symbol of the Spot from which infrared is radiating on the display so that it is easy to figure out the spot where to measure.

What is the correct distance between the instrument and the tire to be measured?