Pressure Monitoring Sensors
Miniature sensors that regulate automobile performance are designed in a very particular way to operate properly while housed directly on moving automobile tires. They need to have the sensitivity to pick up measurements while in motion and the durability to withstand the elements.
Tire pressure is the unsung hero of automobile performance. When inflated to the proper pressure, tires are the exact shape that the designers intended. As air pressure decreases, the tires need more energy to move. Drivers can easily forget to maintain their tire pressure in the day-to-day routine of moving from one place to another. Punctures can take place and go completely unnoticed. That is why having an onboard sensor that alerts the driver when it’s time to add more air makes all the difference. Creating these sensors requires careful consideration of all the fine details, and simulation provides the tools for finding just the right design.
Tire Pressure Sensors Shape Driving Experience
One consequence of low tire pressure is a significant reduction in fuel economy. Additionally, vehicles running on low tires can add tons of greenhouse gases to the atmosphere over time. Low tire pressure can also make it hard for the vehicle to stop, or cause the car to slip on wet surfaces. Automakers are generally required to attach pressure monitoring sensors to wheels that inform drivers if a tire falls below the intended pressure, and Schrader Electronics is currently the global market leader in tire pressure monitoring technology.
Schrader Electronics manufactures 45 million sensors annually and provides sensors to leading automotive companies including GM, Ford, and Mercedes. For a sensor to survive road conditions throughout the life of a vehicle, reliability and durability are key. Consideration is given to shock, vibration, pressure, humidity, temperature, and various dynamic forces when designing for the necessary functions, geometry, and materials. Christabel Evans, an engineer with the Schrader Electronics mechanical design team, has been using finite element analysis (FEA) and multiphysics simulation to build successful, efficient tire sensors for all kinds of vehicles.
Designing Better Sensors with FEA
The Hi-Speed Snap-In Tire Pressure Monitoring Sensor, shown in Figure 1, is a frequently-used product at Schrader that mounts directly on the wheel assembly and measures tire pressure—even when the car is in motion. When the tire pressure decreases too much, a warning goes off, alerting the driver that it is time to stop and re-inflate the tire.