Chemical Sensors for CO/NOx-Detection in Automotive Climate Control Systems

A new air quality sensor for climate control in automobiles has been developed. The sensor is designed for use in air conditioning systems with an air intake flap and a charcoal filter. The main indicators for the detection of air pollution are CO and NO_x.

The sensor elements consist of a SnO₂ layer made in thick film technology resulting in small sensor size and high sensitivity at reasonable cost. The sensor elements are packaged together with an evaluation circuit in a water resistant sensor housing for underhood installation. By means of specific dopants the sensor elements have been optimized in order to detect CO and NO_x with very low cross-sensitivity.

This paper describes the design and production of the sensor. The performance of the complete unit under typical field conditions is presented. The sensor is in serial production.