Abstract: A supplemental fuel system for a combustion engine has a primary fuel supply feeding the combustion chamber directly and a supplemental fuel supply which feeds into the combustion air intake. The supply of primary fuel is appropriately reduced or regulated by automatic control and the supply of the supplemental fuel is continuously automatically adjusted to the supply of primary fuel. Initially the supplemental fuel in vapor state is introduced into the air intake until the heat exchange vaporizer system warms up, when there is an automatic shift to the liquid state of supplemental fuel. A temperature compensator in the air intake connected to the supplemental fuel supply holds the temperature of the supplemental fuel at the same temperature as the air with which it is mixed before passing to the final metering orifice and then to the combustion chamber.

Abstract: A combustion engine system has a tank for volatile fuel with a flexible bag inside equipped with its own breather valve separate form the fill pipe for the tank. When the tank is filled, a muff around the full pipe seals the tank against exhaust of volatile vapors, and air from the bag is forced out the breather valve as it is displaced by the liquid fuel until a valve element on the bag shuts off the breather valve, whereby only pure air is vented to the atmosphere. As the tank empties during use, air returns through the breather valve to fill the bag and replace the space in the tank previously occupied by the liquid fuel, and incoming air may be dried. There is a vapor return for the automatic nozzle used to fill the tank with fuel from a stationary reservoir at the filling station and automatic means to prevent filling the tank until the nozzle is sealed in the fill pipe.

Abstract: A combustion engine system has a tank for volatile fuel with a flexible bag inside equipped with its own breather valve separate from the fill pipe for the tank. When the tank is filled, a muff around the full pipe seals the tank against exhaust of volatile vapors, and air from the bag is forced out the breather valve as it is displaced by the liquid fuel until a valve element on the bag shuts off the breather valve, whereby only pure air is vented to the atmosphere. As the tank empties during use, air returns through the breather valve to fill the bag and replace the space in the tank previously occupied by the liquid fuel. A separate valve controlled relief line communicates between the chamber in the tank and a solenoid controlled throttle valve passage so that when the passage is closed by the throttle valve hot soak vapors from the combustion engine are returned to the fuel tank.