Electronics specialist McLaren Applied has delivered the first of its next-generation SAW (Surface Acoustic Wave) Torque Systems to an undisclosed motorsport client that will mandate the part across all entrants in its race series, which is due to switch to hybrid power in 2024.
The company notes that the new torque sensor is a non-contact measurement device based on SAW technology which enables small, lightweight, robust sensors which provide accurate wireless measurement. Each shaft is supplied with a calibration file and is actively thermally compensated over its operating temperature range, further improving precision.
SAW sensors measure torque by using electricity to generate RF (radio frequency) waves. These acoustic waves are reflected off a piezoelectric surface, which deforms in line with the amount of torque the shaft to which it is applied is being subjected to.
By detecting and interpreting the change in the frequency caused by this deformation, a SAW sensor can accurately and reliably communicate a torque measurement for any rotating component, such as the gearbox input shaft or driveshaft. This data can then be used either by teams themselves to measure and control vehicle performance, or by governing bodies to enforce regulations and ensure a level playing field.
McLaren Applied’s new-generation SAW sensor makes use of an AQP (All Quartz Package) which it says aids the simplification of the shaft machining, reduces weight and provides greater resistance to ingress of moisture and contamination. This also results in a more sustainable product as it does not require the yearly recalibration of previous magnetostriction-based sensors.
The first five SAW shafts were recently delivered and have been instrumented and calibrated in partnership with systems manufacturer Transense, who produce and license advanced Surface Acoustic Wave (SAW) wireless and passive sensor systems to measure torque, force, pressure and temperature. Transense COO Nick Hopkins commented, “Transense is particularly pleased to be collaborating with McLaren Applied for these applications, which offer real benefits to the users while showcasing the technology in a demanding and challenging environment.”