PLASMA GENERATOR AND ITS CONTROL METHOD

To provide a plasma generator capable of directly detecting whether or not a discharge electrode itself is wet.SOLUTION: A plasma generator of this invention comprises: at least a pair of discharge electrodes arranged in an exhaust passage of an internal combustion engine; and a power supply device for supplying electrical power to the discharge electrodes. Then, the power supply device supplies a first power having a lower voltage value than a voltage value where plasma is generated at the discharge electrode. When a temperature increasing speed of the discharge electrode ranging from the first power supply starting time to a time after elapsing a predetermined time is compared with a preset reference temperature increasing speed, and the temperature increasing speed of the discharge electrode is slower than the reference temperature increasing speed, the first power is continued to be supplied, and when the temperature increasing speed of the discharge electrode is equal to or more than the reference temperature increasing speed, a second power of a voltage value where plasma is generated between the discharge electrodes, then a direct detection of whether or not the discharge electrode itself is wet to enable occurrence of trouble through electric conduction to be prevented.SELECTED DRAWING: Figure 3 【課題】放電電極自体が、濡れているか否かを直接検知できるプラズマ発生装置の提供。【解決手段】本発明のプラズマ発生装置は、内燃機関の排気経路内に設けられた少なくとも１対の放電電極と、上記放電電極に電力を供給する電力供給装置と、を備える。そして、上記電力供給装置が、上記放電電極にプラズマが発生する電圧値よりも低い電圧値の第１の電力を供給し、上記第１の電力の供給開始時から所定時間経過後までの上記放電電極の昇温速度と、予め設定された基準昇温速度とを比較して、上記放電電極の昇温速度が上記基準昇温速度よりも遅いときは、第１の電力を供給し続け、上記放電電極の昇温速度が上記基準昇温速度以上であるときは、上記放電電極間にプラズマが発生する電圧値の第２の電力を供給することとしており、放電電極自体が、濡れているか否かを直接検知して通電による故障の発生を防止できる。【選択図】図３