Apparatus for alternate liquid or gaseous fuel operation of internal combustion engines

In a system for operating an internal combustion engine on liquid fuel or alternately on gaseous fuel in which the engine has an engine air inlet disposed upstream of means for controlling the supply of liquid fuel and/or air to the engine and intake means communicating with said inlet for mixing air and gaseous fuel from a supply source in proper proportions and supplying the mixture to the engine when operated on gaseous fuel and for providing for a supply of air only to said air inlet when the engine is alternately operated on liquid fuel, the improvement in which the intake means comprises:

• a first closure member having an opening therethrough communicating with the engine air inlet;
• a first surface associated with the first closure member and surrounding said opening;
• a second closure member having opposite faces;
• a second surface associated with one of said faces of the second closure member and in opposed spaced relation to the first surface, said first and second surfaces defining a passage therebetween communicating at its upstream end with the atmosphere and at its downstream end with said opening;
• a third closure member, the second and third closure members at least partially defining a chamber on the other face of the second closure member, the second closure member and surface being movable relative to and between the first and third closure members between a first limit position adjacent the first closure member and surface and a second limit position more adjacent the third closure member, said first and second surfaces when the second closure member and surface are in their first limit position forming an annular throat in said passage of venturi shape in cross-section around and adjacent said opening for flow of mixed air and gaseous fuel to said opening, the second closure member and surface when in their second limit position providing for a substantially less restricted flow of air only through said passage to said opening;
• one or more gaseous fuel outlet ports spaced around said throat and opening thereinto through one of said surfaces, said gaseous fuel outlet ports being in fluid communication with said chamber during engine operation on liquid fuel;
• and a gaseous fuel inlet in fluid communication with said chamber and said outlet ports for supply of gaseous fuel to said outlet ports at a pressure sufficient to maintain the second closure member and surface in their first limit position during operation of the engine on gaseous fuel, the second closure member and surface being effective to be automatically disposed toward their second limit position when supply of gaseous fuel to said inlet is closed off during operation of the engine on liquid fuel.

Conversion means for use with an internal combustion engine having an atmospheric air inlet upstream of means for controlling supply of liquid fuel and/or air to the engine, said inlet including an air cleaner assembly having spaced circular and annular closure members and an annular air filter element therebetween, atmospheric air passing first through the filter element and then between said closure members and into the air inlet through the annular closure member, the conversion means converting the air cleaner assembly for operation of the engine on either liquid or gaseous fuel and comprising:

• a diaphragm assembly and an annular adapter assembly, the diaphragm assembly including a circular diaphragm plate and a flexible diaphragm attached to the diaphragm plate, the outer margin of the diaphragm being securable around an outer margin of the circular closure member to form a chamber between the diaphragm assembly and the circular closure member, the annular adapter assembly being substitutable for the annular closure member, the annular adapter assembly including first and second spaced annular plates forming an annular chamber therebetween in concentric spaced relation to the diaphragm plate, the diaphragm plate being movable by virtue of the diaphragm between the circular closure member and the first annular plate, the diaphragm plate and the first annular plate being effective to provide an annular venturi therebetween when the diaphragm plate is adjacent the first annular plate, the first annular plate having one or more gaseous fuel outlet ports therethrough into the annular chamber;
• a gaseous fuel inlet fitting having inlet and outlet ends for communicating at its outlet end with the annular chamber through the second annular plate, the inlet fitting being adapted at a location thereon between said ends thereof for communication with the first named chamber through fluid conduit means;
• and a load adjusting valve disposed in the inlet fitting between its outlet end and said location thereon.