To provide an EGR cooler bypass structure having a small and simple structure for shutting off an EGR passage having a bypass line bypassing an EGR cooler, on the upstream side of the EGR cooler.
The EGR cooler bypass structure comprises a flow-in port 77, a flow-out port 78, the EGR cooler 42, an upstream chamber 79 communicated with both the flow-in port 77 and a cooler inlet 71, a downstream chamber 80 communicated with both the flow-out port 78 and a cooler outlet 72, a bypass opening 81 for communicating the upstream chamber 79 with the downstream chamber 80, and a swing valve 82 rockable around a rotating shaft 83 located on the opposite side to the EGR cooler 42 via the bypass opening 81. The swing valve 82 is displaceable to a shut-off position for shutting off the flow-in port 77, a cooler position of shutting off the bypass opening 81, and a bypass position for allowing distribution from the flow-in port 77 through the bypass opening 81 to the flow-out port 78.
Mamoru Takada
Hidekazu Onishi
Yasuo Koizumi
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