Noise reduction air duct of engine

The invention discloses an engine silencing air duct in the technical field of silencing air ducts, which comprises an air duct body, a connecting pipe communicated with the air duct body is fixedly arranged on the side wall of the air duct body, an expansion chamber is fixedly connected to one end, far away from the air duct body, of the connecting pipe, and a first resonance chamber, a second resonance chamber and a third resonance chamber communicated with the air duct body are fixedly arranged on the side wall of the air duct body. A filtering mechanism and an air guide mechanism are clamped on the inner wall of the air pipe body, the filtering mechanism is fixedly connected with the air guide mechanism, the filtering mechanism comprises a filtering pipe clamped on the inner wall of the air pipe body, and a filtering plate is fixedly arranged at the end, close to the air guide mechanism, of the inner wall of the filtering pipe; a plurality of double-end funnels which are communicated with the filtering me