Abstract: Liquid gasoline introduced from a suitable source into a treatment tank of the system is transformed into a relatively dry vaporous state substantially free from large droplets or similar particles. Pellets within an outer chamber of the vessel are propelled by air streams into engagement with each other, and with walls of the vessel, and generate frictional heat. Baffle members in an inner chamber of the vessel reduce the size of droplets of gasoline in such chamber. Dry gas is conducted from the treatment vessel to a holding tank, from whence it is supplied to the intake manifold of the engine. Valves of the system are operated in response to actuation of an accelerator associated with the engine. Liquid gasoline from a lower portion of the vessel is supplied to the intake manifold of the engine during initial start-up, and at other times when no dry gasoline vapor is present within the holding tank.