Abstract: A combination gas vaporizer-air filter comprising a housing fuel supply means for fluid to be vaporized and an ultrasonic transducer in the housing for vaporizing fluid from said fuel supply means, air inlet means in the housing, outlet means in the housing and air filter in the housing adjacent the air inlet means. The vaporized fluid and air in the housing being intimately mixed prior to discharge from the outlet means, duct means connecting said housing to the intake manifold of an internal combustion engine. The outlet means communicate with the duct means, whereby the mixture or vaporized fluid and air may pass from the outlet means to said duct and then to said intake manifold.