| 摘要 |
PROBLEM TO BE SOLVED: To provide an exhaust gas recirculation device for an internal combustion engine, correctly diagnosing cooling abnormality of an EGR cooler. SOLUTION: The exhaust gas recirculation device 120 for an internal combustion engine comprises an exhaust gas recirculation passage 122 connecting an exhaust passage 112 and an intake passage 106 of an engine. The exhaust gas recirculation passage 122 is provided with: an EGR control valve 124 controlling an exhaust gas recirculation amount; the EGR cooler 126 cooling recirculated exhaust gas; a bypass passage 128 bypassing the EGR cooler; and a switching control valve 129 controlling a flow into the bypass passage. The exhaust gas recirculation device 120 further comprises: a temperature detection means 130 disposed to the downstream of the switching control valve 129; a switching control valve operation means for switching and operating the switching control valve at a predetermined time; and a diagnosis means diagnosing the cooling abnormality of the EGR cooler 126 based on difference in temperature detected by the temperature detection means before and after a switching operation of the switching control valve by the switching control valve operation means. COPYRIGHT: (C)2008,JPO&INPIT
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