The art of noise (reduction)

As racecars rely ever more heavily on electrical devices, shielding them from interference becomes critical. Racecar asks if graphene-based coatings are the answer

- STEWART MITCHELL

A Formula 1 car is an exceptionally harsh and ‘noisy’ place for a sensor, with many sources of vibration and electromagnetic interference (EMI) present, all of which have the potential to skew sensor readings and make life difficult for efficient performance.

EMI is the interference caused by one electrical or electronic device to another by the electromagnetic fields generated during its operation.

One of the biggest challenges faced in Formula 1 since introducing hybrid powertrains in 2014 has been protecting devices from the EMI produced by the high-voltage electrical circuits related to the energy recovery system (ERS) and, in particular, the motor-generator units (MGUs).

Even just packaging what is essentially very complex machinery that relies on sensitive measuring devices in such a way that they can survive under racing conditions has proven to be a major challenge for the engineers involved.

EMI is a particular issue in sensors with low output signals, such as strain gauges and thermocouples. Sensors such as pressure transducers can have an output voltage of 1-10V, whereas the output of strain gauges and thermocouples will only be a few milli- or microvolts.

In this case, a low signal-to-noise ratio can have a considerable impact on the recorded output of a sensor. This ratio is the level of a particular signal’s strength compared to the level of background noise.

For example, a sensor with a 5V output signal and a background level of signal noise of a few microvolts would have a very high signal-to-noise ratio. However, if the sensor output is in the millivolt range, the ratio is much lower, making it much harder to distinguish the signal from the noise.