Automotive Air Quality

AppliedSensor MOS Sensor-based ACM Module for Automotive Air Intake Systems features high sensitivity, selectivity and fast response to broad spectrum of target gases.

Drivers and car passengers encounter high levels of pollution in urban driving situations when crossing major intersections, sitting in heavy traffic, passing through congested areas or tunnels, or following high-polluting vehicles. Gasoline-powered car engines generate CO (reducing gas) and unburned hydrocarbons, while diesel engines emit NO2 (oxidizing gas) and unburned hydrocarbons. In specific traffic situations, concentrations of these pollutants can reach levels far above the regulated threshold limits. To prevent these hazardous and foul-smelling substances from entering the car cabin, automotive manufacturers recently began installing air quality sensors in their high-end models and are now also beginning to include air quality sensors as standard features in mid-priced and economy cars.

AppliedSensor’s micro-machined metal oxide semiconductor (MOS) technology has been accepted by our partner, Sensata Technologies, formerly Texas Instruments' Sensors and Control Division, as the basis for joint development of the Air Classification Module, or ACM. Located near the fresh air inlet in the car’s HVAC system, the module reduces the amount of pollutants entering the vehicle cabin by signaling the fresh air inlet door/ventilation flap to close when undesirable substances are detected. The module is equipped with two MOS sensor elements; one optimized to detect reducing gases such as CO and hydrocarbons, and the other optimized to detect oxidizing gases such as NO2. To determine specific air quality levels, resistance changes of the sensor elements in the presence of these gases are translated into real concentrations. The ACM module automatically signals the climate control system to close or to open the air inlet door/ventilation flap within seconds of detecting threshold levels for target gases. The result is consistent, high-quality air in the vehicle cabin without requiring the driver to fumble for the recirculation button.

Competitive Edge: During comparative field tests of air quality sensors, the ACM, based on AppliedSensor MOS sensors, demonstrated high sensitivity and selectivity, as well as fast response to a broad spectrum of target gases. In addition, relative to competitors, the modules have excellent reproducibility from module to module, superior reliability and stability over time and lower power consumption.

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