| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a PM (particulate matter) detection device accurately detecting an amount of PM accumulation with a simple construction. <P>SOLUTION: The PM detection device includes: a PM sensor 3 varying in electrostatic capacity according to the amount of the PM accumulation amount; a bridge circuit 9 in which a variable resistor 4 and fixed resistors 5-7 are connected sequentially, the PM sensor 3 is connected in parallel to the variable resistor 4, and a variable capacitor 8 with electrostatic capacity controllable by changing a connecting combination of a plurality of fixed capacitors 41a-41h is connected in parallel to the fixed resistor 5 adjoining the variable resistor 4; and a detecting part 12 adjusting the variable resistor 4 by applying direct current voltage between voltage application points a, b so that the bridge circuit 9 is balanced, then adjusting the variable capacitor 8 by applying alternating current voltage between the voltage application points a, b so that the bridge circuit 9 is balanced and detecting the amount of the PM accumulation from the electrostatic capacity of the variable capacitor 8. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
