| 摘要 |
PROBLEM TO BE SOLVED: To prevent fluctuation in the output from a detecting element or deterioration of responsiveness by heating up a protector higher by a desired temperature than the exhaust gas temperature thereby preventing adhesion or deposition of PM(particulate matter) in the exhaust gas to the protector. SOLUTION: A tubular ceramic heater 4 is inserted into the outer tube part 2 of a protector and fitted in place. The tubular ceramic heater 4 is then heated by supplying a current through a lead wire 4B in order to heat the outer tube part 2 and the inner tubular part of the protector thus preventing the PM in the exhaust gas of a diesel engine from adhering to the protector. The PM adheres and deposits easily when the exhaust gas temperature of a diesel engine is low in idling, for example. The heating temperature is thereby set such that the temperature of the protector will be about 200 deg.C or above. Since the temperature difference between the protector and the exhaust gas is high enough to prevent adhesion of the PM even when the exhaust gas temperature increases, adhesion and deposition of the PM can be prevented. |
