Patent ID: 8037738

Claim:
A sensor for detecting and monitoring particulate matter within an exhaust gas flow path of an engine, the sensor comprising: a housing including an attachment feature for mounting the sensor; a sensing rod supported by an insulator disposed within the housing, the sensing rod being attached to the insulator and including a probe adapted to be placed within the exhaust gas flow path, the sensing rod being configured to detect an amount of particulate matter that has flowed through the exhaust component and generate signals based thereupon; an electrical connector in communication with the sensing rod, the electrical connector being configured to transmit the signal generated by the sensing rod to a controller; a coil spring in direct contact with the sensing rod and the electrical connector for providing electrical communication therebetween, wherein the sensing rod includes a stepped collar for engaging the coil spring and the electrical connector includes a stepped collar for engaging the coil spring; and wherein the sensing rod includes an electrically insulating layer comprising an oxide coating formed over the sensing rod, the electrically insulating layer providing electrical insulation between the sensing rod and the housing; and the probe includes a section having an increased surface area per unit length as compared to at least one other section of the probe.