Gas adequate mixing structure and exhaust gas recirculation system

The utility model discloses a gas adequate mixing structure and an exhaust gas recirculation system. The gas adequate mixing structure comprises a first pipe body and a second body, wherein the first pipe body comprises an outer part section and an inner part section inserted into an inner cavity of the second pipe body, and the first pipe body and the second pipe body are fixedly connected in a sealing mode. The included angle between the air inlet direction of an end opening of the inner part section and the air inlet direction of gas flowing through the end opening in the second pipe body is 80-110 degrees, the length L of the inner part section is from one fourth of the inner diameter of the second pipe body to three fourth of the inner diameter of the second pipe body, and the end opening of the inner part section is an oblique incision extending from the starting end of the inner part section to the tail end of the inner part section. Due to the fact that the included angle between the introducing direction of EGR waste gas and the flowing-into direction of fresh air at an outlet of the EGR waste gas, the depth of a waste gas guide pipe , inserted into an inlet manifold, of the waste gas guide pipe, and the shape of the oblique incision at the outlet of the waste gas guide pipe are set, the EGR waste gas and the fresh air can be mixed adequately, the adequately mixed gas enters all air cylinders, and normal work of an engine can be ensured.