Air Pressure Sensor

Basic Description

Pressure is a non-directional force in gasses and liquids that is expressed as function of force over a given surface area (e.g. pounds per square inch or PSI). Depending on the application, it may be useful to know the pressure in a given environment in either absolute terms or relative terms. Absolute pressure refers to the amount of pressure in a certain system in relation to zero pressure. Relative pressure on the other hand, refers to the pressure as it relates to the ambient or surrounding pressure.

Many automotive systems depend on pressure measurement to function properly. Pressure sensors are used in the intake manifold, brake system, hydraulic or pneumatic suspension systems, tire pressure monitoring systems, air conditioning systems, and several other systems.

Different types of pressure sensors employ various technologies. Sensors that use piezoresistive strain gauges take advantage of the electro-mechanical properties of certain materials. As pressure is applied to a diaphragm containing a piezoresistive element, the diaphragm deflects causing the piezoresistive element to bend resulting in a change in its resistance. The change in the resistance of the element can then be used to determine the pressure behind the diaphragm. Similarly, piezoelectric elements generate an electric potential proportional to the material deformation. Other pressure sensor technologies are based on electromagnetic, optical or potentiometric effects. Though the technologies differ, the basic principle behind them is the same. Each pressure sensor detects the strain or displacement of a material within the sensor and translates that information into a pressure value.

 

Manufacturers

Airtex, All Sensors, Bosch, Denso, Freescale, Futek, Honeywell

For More Information

[1] Pressure Sensors, Autoshop101 [pdf].

[2] Pressure Sensor, Wikipedia.

[3] SensorsONE, Pressure sensor retailer website.