Apparatus and system for controlling the air-fuel ratio supplied to a combustion engine

Claim 1

A fuel metering system for a combustion engine having engine exhaust conduit means, comprising fuel carbureting means for supplying metered fuel flow to said engine, said carbureting means comprising first and second induction passage means for supplying motive fluid to said engine, a source of fuel, primary main fuel metering system means communicating generally between said source of fuel and said first induction passage means, idle fuel metering system means communicating generally between said source of fuel and said first induction passage means, secondary main fuel metering system means communicating generally between said source of fuel and said second induction passage means, controlled modulating valving means effective to controllably increase and decrease the rate of metered fuel flow through each of said primary and secondary main fuel metering system means and said idle fuel metering system means, oxygen sensor means effective for sensing the relative amount of oxygen present in engine exhaust gases flowing through said exhaust conduit means and producing in accordance therewith a first output, said modulating valving means comprising solenoid winding means for actuation of said modulating valving means, electrical logic control means effective for receiving said first output signal and in response thereto producing a second output and effectively applying said second output to said solenoid winding means to thereby cause said modulating valve means to alter said rate of metered fuel flow through each of said primary and secondary main fuel metering system means and said idle fuel metering system means as to provide for rates of metered fuel flow therethrough ranging from a preselected "lean" fuel-air mixture ratio supplied to said engine to a preselected "rich" fuel-air mixture ratio supplied to the engine, said modulating valving means being effective upon occurrence of an electrical failure in said electrical logic control or said solenoid winding means to thereafter permit only that rate of metered fuel flow through each of said primary and secondary main fuel metering system means and said idle fuel metering system means as will result in said preselected "lean" fuel-air mixture ratio being supplied to said engine, wherein said idle fuel metering system means comprises idle air bleed means, wherein said primary main fuel metering system means comprises first fuel flow orifice means, wherein said secondary main fuel metering system means comprises second fuel flow orifice means, wherein said idle air bleed means is spaced from both of said first and second fuel flow orifice means, said modulating valving means comprising housing means, said housing means comprising a first end portion, a second end portion, said first end portion being adapted for operative connection to said carbureting means, said second end portion being adapted for operative connection to said carbureting means, solenoid motor means, said solenoid motor means comprising axially extending spool means, said spool means comprising a generally centrally disposed tubular portion, said solenoid winding means being carried by said spool means, axially extending armature means situated in said tubular portion for reciprocating movement therein, motion transmitting means operatively connected to a first end of said armature means and generally axially aligned therewith, a first opening formed through said first end portion for permitting the free axial movement of said armature means therein, a second opening formed through said second end portion for permitting the free movement of said motion transmitting means therein, a first valve member operatively connected to a second end of said armature means opposite to said first end, said first valve member being effectively juxtaposed to both of said first and second fuel flow orifice means, a second valve member operatively connected to said motion transmitting means, said second valve member being effectively juxtaposed to said air bleed means, said first and second valve members moving in unison with said armature means so that when said first valve member moved toward both said first and second fuel flow orifice means said second valve member moves away from said air bleed means and when said first valve member moves away from both of said first and second fuel flow orifice means said second valve member moves toward said air bleed means, and resilient means effective for continually resiliently urging said armature means in a direction whereby said first valve member is moved toward both of said first and second fuel flow orifice means and said second valve member is moved away from said air bleed means.