Waste-gas Venturi tube self-cleaning method and system for engine

The invention discloses a waste-gas Venturi tube self-cleaning method and system for an engine, and relates to the field of engines. The method comprises the following steps: before self cleaning, firstly determining whether self-cleaning conditions are established; if the conditions are true, generating a corresponding control signal; starting self-cleaning time measurement according to the control signal, controlling the opening degree of an EGR valve greater than 0, controlling a turbocharger to adjust driving pressure difference P to be self-cleaning driving pressure difference P, wherein the self-cleaning driving pressure difference P is negative, allowing fresh air flowing through a compressor to reversely flow through an EGR pipeline under the action of the pressure difference to realize backflush of a Venturi tube; and when the measured time reaches preset time T1, switching the turbocharger and the EGR valve for normal operation. According to the method, the driving pressure difference P is adjusted