| 摘要 |
PROBLEM TO BE SOLVED: To prevent an increase of the slide resistance of a shaft caused by the adhesion and accumulation of deposits on a clearance part between the shaft and a housing.SOLUTION: A gap distance L1 of a clearance part β at a downstream side is set narrow so that a throttle effect can be obtained. Therefore, such a malfunction that an exhaust gas flows into the clearance part β can be suppressed. On the other hand, a gap distance L2 of the clearance part β at an upstream side in which pressure is lowered by low-pressure generation means γ is set wide. Therefore, the exhaust gas flowing into a seal chamber α can be quickly discharged to an EGR passage 1 from the upstream side of the clearance part β without making the exhaust gas stay in the seal chamber α and the clearance part β. By this constitution, an increase of the slide resistance of a shaft 4 which is generated by the adhesion and accumulation of deposits at the clearance part β can be prevented, and the long-term reliability of an EGR valve can be enhanced.SELECTED DRAWING: Figure 2 |
