This invention has an inlet for either gaseous or liquified gases (LP gas requiring a vaporizer within the system) with the proper passages from the inlet to a back seated fuel valve which is opened by a pressure differential (vacuum from the idle system) across a diaphragm engaging a lever which moves a sealed actuating pin inward to open the fuel valve allowing gaseous fuels to move to the outlet through a proper confining passage. Placed between the outlet and the vacuum chamber of the fuel valve diaphragm is a chamber divided by a free floating diaphragm providing two chambers, one chamber is either balanced for air cleaner resistance or vented to the atmosphere, the other chamber having a free passage to the outlet and a passage in the center of the chamber, having communication with the vacuum side of the fuel valve diaphragm, which is throttled by the floating diaphragm diluting the idle vacuum signal to position the fuel valve.

A gaseous fuel management system for an internal combustion engine having a source of gaseous fuel such as LPG or CNG, a throttle control and an exhaust system and having an air intake tube for conducting combustion air into the manifold of the engine and an angularly movable butterfly valve disposed in the air intake tube, responsive to the operation of the throttle control. A fuel delivery bar having an interior longitudinal fuel conducting bore is diametrically disposed in the air intake tube upstream from the butterfly valve and has a plurality of fuel delivery orifices in its downstream facing side which orifices communicate with the interior of the bar. A fuel lane interconnects the interior bore of the fuel delivery bar to the fuel source and an electronically controlled valve meters the amount of fuel admitted to the interior bore of the fuel delivery bar as a function of the oxygen content of the products of combustion in the exhaust system.

The invention provides a mixture control system for controlling the flow of vaporized hydrocarbons drawn into an engine for combustion and combining a supplemental fuel with the vaporized hydrocarbons as required to maintain a near stoichiometric mixture.

The system includes a metering valve for each cylinder including a main valve and an auxiliary valve. The auxiliary valve is electrically controlled ad via a mechanical, pressure controlled amplifier mechanism, the main orifice in the metering valve is opened.

An integrated fuel control unit for gas-operated internal combustion engines that includes a base on which a primary diaphragm is secured to define a primary fuel chamber. A primary fuel orifice is carried by the base, as is a primary control lever that is coupled to the primary diaphragm for controlling flow of fuel through the primary orifice as a function of inlet fuel pressure and engine demand. A secondary diaphragm is also secured to the base to define a secondary fuel chamber. A secondary orifice is carried by the base between the primary and secondary chambers, and a secondary control lever is coupled to the secondary diaphragm for controlling flow of fuel through the secondary orifice as a function of engine demand. A heat exchange section in the body receives engine coolant or engine oil for heat exchange with fuel so as to heat and vaporize the fuel between the primary and secondary chambers. A high-pressure fuel lock-off is carried by the body, and includes a solenoid coil mounted on the body and a solenoid plunger within the coil for selectively closing an end of the primary orifice remote from the primary control lever. A fuel inlet filter is carried by the body for filtering fuel prior to passage to the primary orifice and the lock-off. The solenoid plunger is normally urged by fuel inlet pressure and by a plunger spring to close the primary orifice, and is withdrawn from the primary orifice against the force of the spring by energization of the solenoid coil when the engine is operating. This feature helps ensure that fuel will not flow to the engine when the engine is not operating.