Exhaust gas recirculation device of engine

摘要

A connecting passage is formed inside a cylinder head, which extends rearward from an exhaust passage and connects to the exhaust passage. The connecting passage branches inside the cylinder head into two branch passages, which open at a rear end face of the cylinder head, respectively. An opening portion, one of opening portions of the branch passages, connects to an EGR cooler, and another opening portion, the other of opening portions of the branch passages, connects to a bypass pipe. Accordingly, the exhaust gas recirculation device of an engine which can restrain the device from being improperly large sized, providing the EGR cooler and the bypass pipe, can be provided.

主权项

1. An exhaust gas recirculation device of an engine, which recirculates part of exhaust gas discharged from an engine body having plural cylinders arranged in line in an engine-body longitudinal direction to an intake manifold arranged on one side of the engine body in an engine-body width direction, comprising:
an exhaust passage provided inside a cylinder head of the cylinder body; a connecting passage provided inside the cylinder head to connect to and extend rearward from the exhaust passage; an EGR cooler cooling part of the recirculated exhaust gas to the intake manifold from the exhaust passage, the EGR cooler including an EGR-gas introduction pipe to introduce the exhaust gas into an EGR cooler body provided inside the EGR cooler, the EGR-gas introduction pipe having a connecting flange integrally formed at an upstream end thereof; a bypass pipe bypassing the EGR cooler and recirculating the exhaust gas from the exhaust passage to the intake manifold, the bypass pipe having a connecting flange integrally formed at an upstream end thereof, wherein said connecting passage branches inside the cylinder head into two branch passages, which open at different positions on a rear end face, in the engine-body longitudinal direction, of the cylinder head, the connecting flange of the EGR-gas introduction pipe of said EGR cooler is connected to the rear end face of the cylinder head so as to connect to one of opening portions of said branch passages for introducing the exhaust gas flowing through the connecting passage into the EGR cooler body, the connecting flange of said bypass pipe is connected to the rear end face of the cylinder head so as to connect to the other of opening portions of said branch passages for flowing the exhaust gas flowing through the connecting passage, bypassing the EGR cooler, and said opening positions of the opening portions where the two branch passages open on the rear end face of the cylinder head are configured such that said one of the opening portions is located further away from the intake manifold, compared to said other of the opening portions, and at a lower level than the other of the opening portions so that the EGR cooler extends in the engine-body width direction at a position behind the rear end face of the engine body and below said bypass pipe.