Engine tail gas diluting and cooling device based on Bernoulli law and debugging method and adjusting method

The invention discloses an engine tail gas diluting and cooling device based on a Bernoulli law. The device comprises a diluting box in diluting connection with a cooling pipe; a flow expanding cylinder communicating with the cooling pipe is arranged in the diluting box; the side wall of the diluting box is inwards connected with a gas sucking port; the end, towards the gas sucking port, of the flow expanding cylinder is connected with a horn port; an annular gap is surrounded between the horn port and the gas sucking port; an intake cavity is surrounded between the flow expanding cylinder andthe diluting box; and the intake cavity is connected with an intake pipe. The invention further discloses a corresponding debugging method and a tail gas adjusting method. Negative pressure can be generated in the annular gap; and environmental air is sucked into the flow expanding cylinder for mixing with exhausted gas of an engine to reduce the exhaust temperature to prevent harm caused by high-temperature tail gas. Th