Automotive Sensors Solve Tough Problems

Randy Frank

Designers of automotive electronics and their automotive customers have truly challenging requirements for sensor suppliers but usually have several suppliers who are more than capable of meeting them. These high-volume applications attract sensor manufacturers who compete with product differentiation and cost to win the design. For example, the most popular vehicle in America, the Ford F-150, has 50 sensors of various types performing functions in powertrain, safety, comfort, and other systems.

Sensors Give Cars New Capabilities
Beyond the traditional pressure, acceleration, temperature, and oxygen sensors that have been used in vehicles for years, new sensing technologies are finding their way into cars. Tire pressure monitoring systems (TPMS), required for all 2008 vehicles sold in the US, add at least four sensors. Others, such as radar and cameras, are providing the ability for the vehicle to detect other vehicles on the road ahead and in blind spots and to provide a warning to the driver. Typically, infrared sensors are used for backup detection to avoid accidents but alternate approaches such as microwave sensing or cameras may provide the answer in future vehicles. Other sensors, such as MEMS gyroscopes and advanced digital accelerometers are employed in electronic stability controls to improve the functionality of these systems.

Wireless sensing promises new possibilities in future vehicles. Already, the TPMS has demonstrated the viability of wireless technology in the vehicle beyond communication and entertainment. However, the potential for new wireless approaches, including the use of ZigBee are just being explored.

In many cases, increased integration is the key to expanding applications, simplifying the design, and reducing system cost. Pressure sensors and accelerometer have demonstrated this capability and continue to grow with new sensor designs. Integrated giant magneto resistive (GMR)-effect sensors are a newer example. Two automotive applications of GMR sensors are for sensing magnetic field strength and angular field direction.

Measuring the higher pressures and temperatures of the combustion process is an extreme application. To improve diesel engine control and achieve a clean diesel, a fiber optic sensing technique used for test and development has emerged as a viable production solution.

With proven success to handle the harsh environment of automotive applications, and meet stringent cost requirements, many automotive sensors are subsequently used in industrial products, appliances, and even toys and games.

For those who are interested in the latest developments in automotive sensors, the Automotive Symposium at Sensors Expo provides greater details on some of these sensor products and their applications in vehicles.