Measurement unit for determining harmful gases esp. in air mixt. in passenger compartment of vehicle - preheats gas mixt. to be monitored to stipulated temp. to reduce effect of interference so that more sensitive gas sensor can be used
摘要
<p>The power of the heating element (22) is regulated using an electrical regulating unit, having at least one regulator and an adjusting element. The measurement temp. is determined by a thermometer probe in the chamber (20). The measurement temp. can be determined using a thermometer probe in the heating element (22). The latter) is made of a material with a marked PTC characteristic, pref. a PTC ceramic. The gas sensor (10) is a semiconductor gas sensor constructed in layers. ADVANTAGE - Gives sensor signal with good stability. Regulation behaviour is stabilised in regulated operation of heating. Reduces temp. gradient between sensor and ambient air.</p>
