| 摘要 |
<P>PROBLEM TO BE SOLVED: To enhance durability of an EGR cooler disposed in an EGR passage. <P>SOLUTION: In an EGR device for an engine E, an exhaust passage 30 is connected with an intake passage 26 by the EGR passage 34, an EGR control valve 35 and the EGR cooler 36 are respectively disposed upstream and downstream of the EGR passage 34. The bypass passage 37 connects the intake passage 26 with the EGR passage 34, so that a portion upstream of a connecting portion of the intake passage with the EGR passage is connected to an intermediate portion between the EGR control valve 35 and the EGR cooler 36. Even if the EGR control valve 35 is closed and exhaust gas remains in the EGR cooler 36, new air flowing from a high pressure portion upstream of the intake passage 26 into the bypass passage 37 passes through the EGR cooler 36 and flows to a low pressure portion downstream of the intake passage 26 to discharge residual exhaust gas in the EGR cooler 36. Therefore, corrosion of the EGR cooler 36 caused by the residual exhaust gas and deposition of carbon are prevented, so that the durability is enhanced. <P>COPYRIGHT: (C)2004,JPO |
