Abstract: An expanded liquified gas mixer to feeding heat engines. The mixer comprises a body whose upper part comprises a cavity divided into two chambers by an elastic membrane. The membrane exhibits in its center an orifice on the edge of which is fastened the upper edge of a register piston which extends downwardly in a blind hole and which slides around a gas intake tube, an air intake duct, and an engine feed duct. An elongated hole is made in the gas intake tube, parallel to its axis, at the level of the ducts.