| 摘要 |
In an internal combustion engine having an exhaust gas recirculation circuit, the efficiency of a turbocharger is raised in a wide engine rotational speed area and, even when a pressure in an intake circuit is higher than that in an exhaust circuit, an exhaust gas can be circulated. For this purpose, an openable intake throttle valve (12e) is provided on the more upstream side than an exhaust gas circulation position of the intake circuit (12), or a narrow portion (12b) is formed on the exhaust gas circulation position of the intake circuit and an intake bypass circuit (12c) for bypassing the narrow portion is provided. Further, an intake and exhaust bypass circuit (20) for connecting the intake circuit to the exhaust circuit (16) is provided. Then, the opening degree of the intake throttle valve or intake bypass circuit and the opening degree of the intake and exhaust bypass circuit are adjusted so as to set the pressure at the exhaust gas circulation position of the intake circuit to be lower than that in an exhaust manifold (16a).
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