QMT Features: December 2009
Electrifying speed
Displacement and temperature sensors improve performance of all-electric motorcycle at Isle Of Man TTX GP

A range of non-contact displacement and temperature sensors from Micro-Epsilon are being used to help improve the performance of an all-electric motorcycle that was entered into the recent Isle of Man TTXGP zero carbon fuel Grand Prix, which took place on 12th June. The race was held on the same day as the premier Senior TT event over the complete Isle of Man TT Mountain Course.

During testing in early 2009, the EV-0 RR motorcycle, designed by EVO Design Solutions, utilised several different non-contact sensors to help improve the bike’s performance. All sensors and electrics used on the bike were fitted and tested by KA Sensors, a specialist provider of sensors and instrumentation equipment to the motor sports industry.

KA Sensors customised Micro-Epsilon’s optoNCDT 1300 non-contact displacement sensor and mounted it to the nose of the bike’s chassis, with the laser window pointing down towards the ground. From here, the high speed (500Hz) sensor is able to accurately measure and monitor the ride height of the motorcycle. The sensor acts as an anti-wheelie device and enables the bike’s designers to adjust the suspension characteristics and engine power mapping in order to optimise the performance of the bike, whilst reducing energy consumption.

The optoNCDT 1300 laser sensor measures displacement against almost any target surface, including shiny black rubber without contacting the object. The sensor has an integrated digital signal processor and is suitable for a wide range of applications in industrial automation and production environments.

The sensor has a measuring range from 20mm up to 200mm, with resolution (static) from 4µm up to 200µm. Linearity is from 40µm up to 400µm and the measuring rate is 500Hz. The sensor weighs just 100g and operates in temperatures from 0°C up to 55°C.

For the EV-0 RR motorcycle, the sensor needed some customisation, as Peter Trevor, sales director at KA Sensors points out: “The bike was tested on private airfield strips in Norfolk, so the conditions were pretty harsh for a standard sensor. There’s a lot of vibration, heat and dirt to contend with. So we developed a special protective, anti-vibration mounting for the sensor. We also introduced a tear-off strip for the sensor’s laser window to protect it from stone damage. This can be replaced after every test session.

On other racing bike projects, KA Sensors has used the optoNCDT 1300 sensor to measure the lean angle of the bike. For this, two identical sensors are positioned in the chassis at 45-degree angles to the ground in order to monitor the change in displacement as the bike travels around the track.

Rear wheel temperature sensors
In addition to the optoNCDT 1300 sensor, KA Sensors also mounted three Micro-Epsilon ‘thermoMETER CS micro’ non-contact temperature sensors on the rear wheel mudguard. These three sensors measure the temperature profile of the tyre during test racing.

The thermoMETER CS micro is a miniature infrared thermometer for OEMs. With rugged silicon-coated optics, the sensor can measure temperatures from –20 deg C up to 350 deg C, with the special motor sport version able to measure up to 1,000 deg C. The sensor electronics are integrated in the cable, saving space, with a separate controller and optional USB programming interface and software.

As Peter Trevor states: “To KA Sensors, the Cs micro is a phenomenal piece of kit in terms of performance and benefits. Its compactness enables us to mount the sensor into mudguards to measure tyre temperatures. The three sensors measure the centre of the tyre, plus the inside and outside edge, giving us a very clear temperature profile of the tyre as the bike moves around the track.”

“This allows us to choose the best tyres and to adjust the suspension system set up of the bike. Basically, the tyres need to be hot and sticky to do their job properly. From a laptop, we can use programming software to adjust all the parameters, such as temperature measurement range and the output voltage. We’ve even used the same sensors to measure the temperature profile of brake discs on motorcycles. Just as important, the software enables us to change the emissivity of the sensor to suit different target materials, such as steel, carbon or rubber,” adds Trevor.

The measuring range of the thermoMETER CS micro is a 10:1 ratio, which means the sensor can be mounted some distance from the target. This meant that KA Sensors could mount the three sensors between 2 and 3cm from the tyre surface, without sacrificing the performance (accuracy and resolution) of the sensor and giving us more room to protect it from the harsh conditions.“

KA Sensors did some customising of the CS micro by fitting a sacrificial protection lens over the laser window. In addition, the electronics, which are integrated into the cable, were given extra protection and housed in a robust carbon tube. “We also need to strain relief the cable against excess vibrations and protect the electronics from the rough handling associated with many bike mechanics,” quips Trevor.

On the bike, KA Sensors uses the device to monitor hot spots on the bike’s cooling system and electrical terminals. The bike has a conventional water-cooled radiator and electric motor that sits in the airflow. As Trevor describes: “We use the thermal imaging camera to see how warm the radiator is and whether it is dissipating the heat as it should be. If it isn’t doing its job, we might change the radiator itself or use a fan to increase the airflow through the radiator, or change the routing of the coolant through the radiator pipes.

We can perform a similar exercise on the bike’s electrical terminals,” he continues. “The bike runs on 48 volts and we have a 600 amp capacity to draw from. If we don’t select the correct cable sizes and terminals, the bike will lose energy through excess heat. The thermal imaging camera allows us to identify which terminals and cables are too hot and rectify the problem.”

Trevor concludes: “We’ve been working as Micro-Epsilon’s UK motor sport partner for three years. We’ve integrated Micro-Epsilon sensors into numerous applications, including F1, GP2, A1 Grand Prix, World Touring Cars, British Touring Cars, Le Mans cars, GT cars, British and World Superbikes.”

email: info@micro-epsilon.co.uk
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