| 摘要 |
Provided is an EGR system (10) which can selectively cool the EGR depending on the operating condition of the engine (1), and is provided with a switching valve (15) having an improved operating stability. The switching valve (15) comprises a valve stem (32) including a first end formed with a poppet valve member (18), a second end connected to a diaphragm actuator (16) and a slidably guided intermediate portion, a cooler port valve seat (29b) communicating with the cooler passage (13b) and a bypass port valve seat (29a) communicating with the bypass passage (13a). The bypass port valve seat (29a) is located adjacent to the diaphragm actuator (16) and the cooler port valve seat (29b) is located remote from the diaphragm actuator (16), with respect to an inlet port (26) communicating with the exhaust manifold (5). |
