Infrared sensors monitor tyre temperatures in real time

A team of researchers at the School of Science and Engineering at University Campus Hamilton (formerly Bell College Glasgow) is using infrared sensors to monitor the temperature of tyres on racing cars in real time around the racing track, enabling set-up changes to be made on the car in order to improve lap times.

The research project involves the use of 12 CS series infrared temperature sensors from Micro-Epsilon, three on each wheel of the racing car to measure the temperature on the inside edge, outside edge and centreline of the tyre. Each sensor is positioned directly above the surface of the tyre, relaying data back to a logging system for further analyses. One of the attractions of the sensor is its ability to be positioned a significant distance from the tyre due to its high-resolution 10:1 optics. In this case, the sensors are positioned 150mm from the tyre but still measure over a small (15mm) diameter surface area. Competing sensors currently on the market measure over a much wider surface area at a distance of 150mm, which makes tyre temperature measurements very difficult to analyse, particularly if the three measuring spots on the inside edge, outside edge and centre line of the tyre cannot be distinguished from one another in the results data. The CS Series can also be easily integrated into existing racecar bodywork.

David Kennedy, Senior Lecturer at Bell College Glasgow and Head of the Research Project, comments: "The research is part of the Product Design with Motorsport course here at the college. We have been working on racecar chassis set up for some years now as part of the Formula Student Competition. The sensors will enable us to improve the performance of the development car by looking at the temperature of the tyres in real time as an indication of how hard they are working. We are using set-piece manoeuvres as well as laps of the circuit to minimise variability due to the driver."

Benefits of real-time monitoring

Monitoring the temperature of tyres is clearly beneficial for race teams, particularly F1 and other Motorsport engineering teams, as it enables the performance of the car to be improved. Traditionally, engineers would measure the temperature of the tyres after the race or test lap is completed, but this means only average rather than real-time temperature readings can be analysed.

Kennedy points out: "Micro-Epsilon demonstrated its CS sensor to us on its stand at the Autosport Engineering Show in January this year. We were impressed by the very fast, almost instantaneous feedback of the infrared CS sensor. We have used the sensors connected to a Pi Research data acquisition system on a car that was driven on a local race track. By analysing the results, we were able to make set-up changes to the car to improve the performance. For example, we noticed that the temperature of the outside edge of the right hand front tyre was low during a particular manoeuvre. We therefore made a change to the camber in order to make more efficient use of the tyre and therefore improve the total grip available, increasing the cornering speed."

Micro-Epsilon's optris CS and optris CSmicro sensor series combine high quality and high accuracy with a rugged, high-grade stainless steel housing. The technology was designed specifically for OEM customers who, to date, may have avoided infrared measurement due to its relative high cost. The optris CS is therefore compact, with an M12 thread, a diameter of 14mm and a length of 87mm. The sensor also comes with integrated electronics, an LED display and a smart sighting support. The optris CS is a rugged device, benefiting from coated silicon optics, so can be used in ambient temperatures of up to 75degC without cooling.

Further features include: a scalable analogue output of 0-10V or 0-5V, adjustable signal processing, short-circuit and polarity reversal protection, a USB programming interface with software and a wide power range of 5-7 or 12-28V DC.

The more recent addition to the range is the optris CSmicro, which is even more compact than the optris CS and measures just 14mm in diameter by 28mm in length, with an M12 thread. Again, the sensor is housed in stainless steel but the processing electronics are integrated in the sensor cable itself, which facilitates smaller sensor dimensions. This enables the sensor to be mounted onto Formula One racing cars and used in other high-performance motorsport applications.

In addition to providing all the features of the optris CS, the optris CSmicro provides a programmable simultaneous alarm output for fast analysis and switching operations. A very fast response time of 30ms (CS and CSmicro) demonstrates the level of technical innovation these sensors bring to the infrared temperature sensor market. The sensor can also be used in ambient temperatures of up to 120degC without having to cool the sensing head.

For more information on Micro-Epsilon's range of infrared temperature sensors for Motorsport applications, email [email protected].