STRUCTURE OF EXHAUST GAS RECIRCULATION PASSAGE OF ENGINE

摘要

PROBLEM TO BE SOLVED: To improve the reliability of an EGR valve 41 and components constituting an exhaust gas recirculation passage for recirculating part of exhaust gas from the exhaust system of an engine 1 to the inlet system thereof while maintaining the favorable combustion state of the engine 1 by sufficiently and stably securing the heat radiation properties of the exhaust gas circulating through the exhaust gas recirculation passage when the inside of a cylinder head 4 having a water jacket w is provided with the exhaust gas recirculation passage. SOLUTION: The upstream end of an EGR passage 37 is opened in the joining surface 34 of a side wall part 4b on the exhaust side of the cylinder head 4 wherein the downstream end of an exhaust port 35 is opened. A recess 36 is formed so that an opening at the upstream end of the EGR passage 37 can communicate with an adjacent opening at the downstream end of the exhaust port 35. An extension part 32a is installed in the mounting flange 32 of an exhaust manifold 30 so as to cover the recess 36, and a capacity chamber surrounded by the extension part 32a and the recess 36 is taken as an EGR introduction space part 40 for introducing the exhaust gas into the EGR passage 37.