Carburetor construction

Claim 2

A carburetor construction comprising: a base plate having a substantially planar surface including an opening adapted for connection to an air inlet passage of an internal combustion engine, said opening defining a socket and said planar surface including a groove extending transversely with respect to said socket; a throat member defining a fuel-air mixing passage mounted on said base plate having a mixture outlet portion thereof in alignment with said opening in said base plate, said throat member having an air inlet portion spaced from said mixture outlet portion and including fuel aperture means extending through a wall portion thereof between said air inlet portion and said mixture outlet portion, said throat member being received within said socket and including a pair of oppositely disposed slots aligned with said groove; a rotatable throttle shaft extending through said slots and journalled in said groove, said throttle shaft including a throttle plate disposed in said mixture outlet portion of said throat member providing a variable restriction in said mixing passage; and a fuel module mounted on said base plate receiving said throat member including fuel channel means arranged and disposed for communication with a source of fuel and with said aperture means in said throat member, said base plate, throat member and fuel module being secured in interlocking engagement.

Claim 3

A carburetor construction according to claim 1, wherein said throttle shaft includes means engageable with an accelerator pump disposed in said fuel module, operable to supply a momentary injection of fuel through said aperture means responsive to movement of said throttle plate to an open position.

Claim 4

A carburetor construction according to claim 1, wherein said throat member includes first and second isolated patterns of circumferentially spaced fuel apertures, said throat member being receivable within said socket in either a first position or a second position for disposing a selected pattern of fuel apertures in communication with said fuel channel.

Claim 5

A carburetor construction according to claim 1, wherein said slots are disposed in a selected relationship with respect to said fuel aperture means, said throttle plate having an edge portion movable with respect to said fuel aperture means in response to turning of said throttle shaft.

Claim 6

A carburetor construction according to claim 4, wherein said fuel aperture means includes an idle fuel aperture disposed adjacent said base plate and a main fuel aperture spaced therefrom, said throttle plate edge portion being arranged for isolating said idle aperture from said main aperture in a closed position, said fuel module including a high speed adjusting plug controlling communication between said main fuel aperture and a common portion of said fuel channel means and an idle adjusting plug controlling communication between said idle fuel aperture and said common portion of said fuel channel means.

Claim 7

A carburetor construction comprising: a base plate having a substantially planar surface including an opening adapted for connection to an air inlet passage of an internal combustion engine; a throat member defining a fuel-air mixing passage mounted on said base plate having a mixture outlet portion thereof in alignment with said opening in said base plate, said throat member having an air inlet portion spaced from said mixture outlet portion and including fuel aperture means extending through a wall portion thereof between said air inlet portion and said mixture outlet portion; and a fuel module mounted on said base plate receiving said throat member including fuel channel means arranged and disposed for communication with a source of fuel and with said aperture means in said throat member, said fuel module including a metering pocket having an end surface, said end surface having a metering orifice defined therein forming a portion of said fuel channel means, said fuel module including a rotatable adjusting plug received in said metering pocket having a spiral ledge defining a metering surface lapping said metering orifice arranged for varying the flow area of said metering orifice in response to rotation of said plug, said metering surface being biased into engagement with said end surface of said metering pocket by means of a resiliently deformable ring engaging a shoulder formed on said adjusting plug and a shoulder formed in said metering pocket.

Claim 8

A carburetor construction comprising: a base plate having a substantially planar surface including an opening adapted for connection to an air inlet passage of an internal combustion engine; a throat member defining a fuel-air mixing passage mounted on said base plate having a mixture outlet portion thereof in alignment with said opening in said base plate, said throat member having an air inlet portion spaced from said mixture outlet portion and including fuel aperture means extending through a wall portion thereof between said air inlet portion and said mixture outlet portion; and a fuel module mounted on said base plate receiving said throat member including fuel channel means arranged and disposed for communication with a source of fuel and with said aperture means in said throat member, said fuel module including a metering pocket having an end surface, said end surface having a metering orifice defined therein forming a portion of said fuel channel means, said fuel module including a rotatable adjusting plug received in said metering pocket having a spiral ledge defining a metering surface lapping said metering orifice arranged for varying the flow area of said metering orifice in response to rotation of said plug, said metering surface being biased into engagement with said end surface of said metering pocket by means of a resiliently deformable ring engaging a shoulder formed on said adjusting plug and a shoulder formed in said metering pocket.

Claim 9

A carburetor construction according to claim 6, wherein said rotatable adjusting plug includes an internal passage communicating with said metering surface, said internal passage forming a portion of said fuel channel means.

Claim 10

A carburetor construction according to claim 7, wherein said rotatable adjusting plug includes a one-way check valve disposed in said internal passage arranged for controlling the direction of flow in said fuel channel means.

Claim 11

A carburetor construction comprising: a base plate having a substantially planar surface including an opening adapted for connection to an air inlet passage of an internal combustion engine, and including a first recess defining a portion of a metering chamber; a throat member defining a fuel-air mixing passage mounted on said base plate having a mixture outlet portion thereof in alignment with said opening in said base plate, said throat member having an air inlet portion spaced from said mixture outlet portion and including fuel aperture means extending through a wall portion thereof between said air inlet portion and said mixture outlet portion; and a fuel module mounted on said base plate receiving said throat member including fuel channel means arranged and disposed for communication with a source of fuel and with said aperture means in said throat member, said fuel module including a first resilient membrane, a metering plate, a second resilient membrane, and a cover plate stacked one upon the other and secured to said base plate, said metering plate including a recess formed in a lower surface thereof cooperating with said first recess and said first resilient membrane to form a portion of said metering chamber, said metering chamber communicating with said source of liquid fuel, said metering plate including a metering pocket communicating with said metering chamber, and an adjusting plug having a portion extending through said cover plate and having another portion received within said metering pocket, said extending portion of said plug including means for adjustably rotating said plug within said pocket, and said other portion of said plug including means for adjustably restricting communication between said metering chamber and pocket, said metering chamber and adjusting plug forming a portion of said fuel channel means.

Claim 12

A carburetor construction comprising: a base plate having a substantially planar surface including an opening adapted for connection to an air inlet passage of an internal combustion engine, and including a first recess defining a portion of a metering chamber; a throat member defining a fuel-air mixing passage mounted on said base plate having a mixture outlet portion thereof in alignment with said opening in said base plate, said throat member having an air inlet portion spaced from said mixture outlet portion and including fuel aperture means extending through a wall portion thereof between said air inlet portion and said mixture outlet portion; and a fuel module mounted on said base plate receiving said throat member including fuel channel means arranged and disposed for communication with a source of fuel and with said aperture means in said throat member, said fuel module including a first resilient membrane, a metering plate, a second resilient membrane, and a cover plate stacked one upon the other and secured to said base plate, said metering plate including a recess formed in a lower surface thereof cooperating with said first recess and said first resilient membrane to form a portion of said metering chamber, said metering chamber communicating with said source of liquid fuel, said metering plate including a metering pocket communicating with said metering chamber, and an adjusting plug having a portion extending through said cover plate and having another portion received within said metering pocket, said extending portion of said plug including means for adjustably rotating said plug within said pocket, and said other portion of said plug including means for adjustably restricting communication between said metering chamber and pocket, said metering chamber and adjusting plug forming a portion of said fuel channel means.

Claim 13

A carburetor construction according to claim 9, wherein said base plate and said metering plate include substantially congruent recesses separated by said first resilient membrane, said recess in said base plate being adapted for communication with a source of pulsating pressure and said recess in said metering plate communicating with a source of fuel and with said metering chamber, said recesses and membrane providing a pump for circulating fuel to said metering chamber.

Claim 14

A carburetor construction comprising: a base plate having a substantially planar surface including an opening adapted for connection to an air inlet passage of an internal combustion engine; a throat member defining a fuel-air mixing passage mounted on said base plate having a mixture outlet portion thereof in alignment with said opening in said base plate, said throat member having an air inlet portion spaced from said mixture outlet portion and including fuel aperture means extending through a wall portion thereof between said air inlet portion and said mixture outlet portion; said throat member including a substantially cylindrical internal wall portion merging into a substantially frusto-conical internal wall portion, the axes of said frusto-conical portion and said cylindrical portion being inclined with respect to each other, said frusto-conical portion including a restricted band defining a venturi disposed between said air inlet portion and said mixture outlet portion; and a fuel module mounted on said base plate receiving said throat member including fuel channel means arranged and disposed for communication with a source of fuel and with said aperture means in said throat member, said base plate, throat member and fuel module being secured in interlocking engagement.

Claim 15

A carburetor construction comprising: a base plate having a substantially planar surface including an opening adapted for connection to an air inlet passage of an internal combustion engine; a throat member defining a fuel-air mixing passage mounted on said base plate having a mixture outlet portion thereof in alignment with said opening in said base plate, said throat member having an air inlet portion spaced from said mixture outlet portion and including fuel aperture means extending through a wall portion thereof between said air inlet portion and said mixture outlet portion; said throat member including a substantially cylindrical internal wall portion merging into a substantially frusto-conical internal wall portion, the axes of said frusto-conical portion and said cylindrical portion being inclined with respect to each other, said frusto-conical portion including a restricted band defining a venturi disposed between said air inlet portion and said mixture outlet portion; and a fuel module mounted on said base plate receiving said throat member including fuel channel means arranged and disposed for communication with a source of fuel and with said aperture means in said throat member, said base plate, throat member and fuel module being secured in interlocking engagement.