The design of the Dynex electronic carburetion system for gaseous fuels (propane and methane), by N.G.V. Fuel Technologies, Inc., is presented. The design and draw-backs of previous and existing systems are described, leading to the parameters dictating the design of an “ideal” system. Prototypes of three variants of the electronic system have been made and tested with promising results. Patents for the invention have been issued. The system does not require the use of a computer or fuel injectors, but senses the engine speed and manifold pressure in order to regulate the pressure and flow rate of the gaseous fuel being admitted to the engine. No carburetors (mixers) or adapters are required. Performance and emissions on (dual-fuel) gasoline operation are not impaired. The system can be used for gaseous fuel supplementing of two-stroke and four-stroke diesel engines, and also for controlling a liquid propane injection system.