Suitable for use in extreme and hostile conditions, Penny + Giles’ sensors are being specified for a range of applications in the Formula One arena
Success in motor racing – and especially in F1 – depends on tens of thousands of components working together at peak performance under extreme operating conditions. Engines that can rev up to 19,000 rpm means a single piston completes 300 cycles per second. In addition, brake discs have to withstand operating temperatures in excess of 1000°C, and gears can be selected up to 4000 times per race.
Of the 80,000 or so components in a typical F1 car, there are over 100 sensors linked to more than 1km of cable. Of these, position sensors are essential in controlling and monitoring systems that supply information to the team’s race engineers to help trim precious tenths of a second off lap times.
F1 challenges
For the 2012 season, Penny + Giles LVDTs, rotary potentiometers and Hall effect rotary and linear sensors are being used by eleven F1 teams representing 22 of the 24 cars.
However, every F1 car presents a different challenge because, in effect, these are prototypes. With the focus on performance, weight and size, sensors have to fit into spaces that are left over. They also need to succeed in a two-hour operational race window, in environments where running temperatures can exceed 130°C, with soaks of over 150°C when cars are stationary in the pits or on the starting grid.
This season, control and feedback applications for Penny + Giles sensors include gearbox sensing for forward/
reverse gear position select and interlock and barrel position; brake sensing including pad wear and master cylinder; engine and pedal sensing including throttle and pedal positioning; power steering spool and rack position, steering angle and front/rear suspension sensing; and hydraulic reservoir position sensing.
Evolving technology
Sensors for each application have, however, evolved over the years.
Gearbox sensors: The company was tasked with designing and developing a replacement for a gearbox sensor that was oversized for its application. Because it was running off a 12Vdc supply, the original sensor also had temperature issues, which made it brittle over time. Penny + Giles engineers analysed various materials and re-designed the sensor using an organic polymer thermoplastic with strong mechanical properties at elevated temperatures. This not only reduced the size and weight of the sensor, but also meant it was extremely strong and with a good temperature coefficient.
At the end of that season the team asked for the sensor to be made smaller, lighter and faster, so Penny + Giles developed the sensor to work from a 5Vdc supply. This meant the voltage regulators could be removed, further reducing the size and weight.
Brake positioning/pad wear sensing: With temperatures in excess of 1000°C involved, many teams use Linear Variable Differential Transformers (LVDTs) which, over the years, have reduced in size. Many teams now use a 6mm diameter LVDT, which is 25% smaller than those being used a couple of years ago. A smaller LVDT means less material is used to mount them, which provides a weight advantage, as well as improvements in dynamic shock and vibration performance.
Master cylinders: Historically, teams have mounted a linear potentiometer on brackets alongside the master cylinder to provide measurement feedback. In recent years Penny + Giles has worked with manufacturers to integrate a magnet into the push/pull rod and have embedded a Hall effect sensor within the body of the master cylinders. This has eliminated the need for brackets, therefore reducing weight and providing a cleaner solution.
Pedal sensing: Many teams have historically used linear potentiometers for pedal sensing applications but these require mounting brackets. A few years ago Penny + Giles engineers developed a two-piece sensor – using the same principle as its NRH style dual-output ‘non-contact’ rotary position sensor – which is now mounted on the pedal’s natural rotary pivot point. This has helped to reduce the space envelope and eliminate signal noise.
Front/rear suspension: Again, the company has seen a shift from potentiometer-based linear sensors to Hall effect rotary sensors that, like the pedal-sensing applications, use natural pivot points on the bell cranks.
Steering angle: The company was tasked with developing a steering angle sensor for one team that had limited space because the sensors would be mounted at the end of the steering column within the nose cone. A miniature Hall effect rotary sensor was developed, which exceeded the team’s expectations regarding space and has proved to be technologically superior to anything used before.
Clutch position: In a recent clutch position application one team had been experiencing problems with cross-talk, wear, temperature instability and electrical noise from its Hall effect sensor supplied by another company. A Penny + Giles LVDT eliminated these problems.
LVDT solutions
Penny + Giles’ high-performance ratiometric LVDT’s can be supplied in a range of shaft and body configurations to suit clutch, gearbox, engine and brake applications. These benefit from the experience the company has gained in fly-by-wire control systems for flight-critical aerospace applications; using high-integrity coil, screen and connection assemblies, combined with welded and vacuum brazed stainless steel construction.
Furthermore, the company’s rotary potentiometers are race-proven and suited to providing data acquisition systems with clean, robust signals for throttle angle, steering angle and gear select position indication. The use of highly durable rotary potentiometer track technology provides virtually infinite resolution, low electrical noise and high stability, especially under the extremes of temperature, humidity, vibration and shock experienced over a long operating life.
Contactless rotary and linear position sensors, featuring the latest Hall effect ‘System-on-Chip’ technology, have been tested to withstand severe shock and vibration and operating temperatures to +170°C, ensuring survival in the most rugged of motorsport applications.
Penny + Giles
T: 01202 409499
