Carburetor having a choke device

Claim 2

In a carburetor serving an internal combustion engine and including a fuel metering device which has means defining a fuel outlet opening disposed in the zone of the longitudinal axis of the flow passage of an intake manifold having walls defining the flow passage; an arbitrarily actuatable throttle flap situated in the flow passage downstream of the fuel outlet opening; a choke means situated in the flow passage upstream of the fuel outlet opening for the pressure-dependent setting of the cross-sectional area of the flow passage, the improvement comprising a. two planar, quadrangular choke flaps situated generally side-by-side in said flow passage transversely to the manifold axis; said choke flaps forming part of said choke means and each having 1. a first edge zone extending along the manifold wall in close vicinity thereof; the first edge zones of the one and the other said choke flap being remote with respect to one another; 2. a second edge zone extending generally parallel to said first edge zone; the second edge zones of the one and the other choke flap being adjacent one another and together defining a cross-sectional area of said flow passage; b. means defining recesses in the manifold wall at opposite locations transversely to the manifold axis; c. pivotal support means held in said recesses and connected to each said choke flap for providing pivotal motion of each choke flap about a pivotal axis extending in and along said first edge zone of each choke flap; the pivotal axes of the one and the other choke flap being parallel to one another; d. a manifold wall portion defining a quadrangular cross section of the flow passage of said intake manifold in the zone of said choke flaps, said wall portion closely surrounding said choke flaps in any pivotal position thereof; e. means for effecting a face-to-face engagment of each choke flap with said wall portion in a fully open position of said choke flaps; f. spring means connected to one of said choke flaps for urging the latter in the direction of said fully open position; and g. means for so arranging said choke flaps with respect to one another that in a closed position of said choke flaps the other of said choke flaps overlaps, with its said second edge zone, the second edge zone of said one choke flap for allowing pivotal motion of said one choke flap against the force of said spring means beyond said closed position in response to backlash pressures in said flow passage.

Claim 3

A carburetor as defined in claim 1, wherein said quadrangular cross section has the shape of a rectangle, said pivotal axes being oriented perpendicularly to the long sides of the rectangle.

Claim 4

A carburetor as defined in claim 1, further comprising a manifold wall portion defining a circular cross section of the flow passage of said intake manifold in the zone of said throttle flap.

Claim 5

A carburetor as defined in claim 1, further comprising means defining cutouts in said second edge zone of each choke flap; said fuel metering device including a metering needle passing through said fuel outlet opening and extending within said flow passage transversely to the axis thereof, said metering needle intersecting the travelling path of said choke flaps and being in alignment with said cutouts.

Claim 6

A carburetor as defined in claim 4, further comprising a spring means connected to said metering needle for urging it towards a closed position; and a lever affixed to one of said choke flaps and coupled to said metering needle for effecting a synchronous opening movement of said choke means and said metering needle; said spring means and said lever being disposed externally of said flow passage.

Claim 7

In a carburetor serving an internal combustion engine and including a fuel metering device which has means defining a fuel outlet opening disposed in the zone of the longitudinal axis of the flow passage of an intake manifold having walls defining the flow passage; an arbitrarily actuatable throttle flap situated in the flow passage downstream of the fuel outlet opening; a choke means situated in the flow passage upstream of the fuel outlet opening for the pressure-dependent setting of the cross-sectional area of the flow passage, the improvement comprising a. a first and a second planar, quadrangular choke flap situated generally side-by-side in said flow passage transversely to the manifold axis; said choke flaps forming part of said choke means and each having 1. a first edge zone extending along the manifold wall in close vicinity thereof; the first edge zones of the first and the second choke flap being remote with respect to one another; 2. a second edge zone extending generally parallel to said first edge zone; the second edge zones of the first and the second choke flap being adjacent one another and together defining a cross-sectional area of said flow passage; b. means defining recesses in the manifold wall at opposite locations transversely to the manifold axis; c. pivotal support means held in said recesses and connected to each said choke flap for providing pivotal motion of each choke flap about a pivotal axis extending in and along said first edge zone of each choke flap; the pivotal axes of the first and the second choke flap being parallel to one another; d. a manifold wall portion defining a quadrangular cross section of the flow passage of said intake manifold in the zone of said choke flaps, said wall portion closely surrounding said choke flaps in any pivotal position thereof; e. means for effecting a face-to-face engagement of each choke flap with said wall portion in a fully open position of said choke flaps; f. a first lever having first and second ends; said first end of said first lever being rigidly connected to said first choke flap; g. a second lever having first and second ends; h. means for jointedly connecting said first end of said second lever to said second choke flap; i. abutment means positioned between said first end of said second lever and said second choke flap for determining a maximum angl between said second choke flap and said second lever; j. a first spring connected to said second choke flap for urging the same away from said second lever towards said maxmum angle; k. a third lver having two ends being jointedly connected to the respective second ends of said first and second levers; a second spring connected to said first choke flap for directly urging the latter towards said closed position and for indirectly urging said second choke flap into said closed position by said first, second and third levers; and m. means for so arranging said choke flaps with respect to one another that in a closed position of said choke flaps said first choke flap overlaps, with its said second edge zone, the second edge zone of said second choke flap for allowing pivotal motion of said second choke flap relative to said second lever against the force of said first spring beyond said closed position in response to backlash pressures in said flow passage.

Claim 8

In a carburetor serving an internal combustion engine and including a fuel metering device which has means defining a fuel outlet opening disposed in the zone of the longitudinal axis of the flow passage of an intake manifold having walls defining the flow passage; an arbitrarily actuatable throttle flap situated in the flow passage downstream of the fuel outlet opening; a choke means situated in the flow passage upstream of the fuel outlet opening for the pressure-dependent setting of the cross-sectional area of the flow passage, the improvement comprising a. a first and a second planar, quadrangular choke flap situated generally side-by-side in said flow passage transversely to the manifold axis; said choke flaps forming part of said choke means and each having 1. a first edge zone extending along the manifold wall in close vicinity thereof; the first edge zones of the first and the second choke flap being remote with respect to one another; 2. a second edge zone extending generally parallel to said first edge zone; the second edge zones of the first and the second choke flap being adjacent one another and together defining a cross-sectional area of said flow passage; b. means defining recesses in the manifold wall at opposite locations transversely to the manifold axis; c. pivotal support means held in said recesses and connected to each said choke flap for providing pivotal motion of each choke flap about a pivotal axis extending in and along said first edge zone of each choke flap; the pivotal axes of the first and the second choke flap being parallel to one another; d. a manifold wall portion defining a quadrangular cross section of the flow passage of said intake manifold in the zone of said choke flaps, said wall portion closely surrounding said choke flaps in any pivotal position thereof; e. means for effecting a face-to-face engagement of each choke flap with said wall portion in a fully open position of said choke flaps; f. a first lever having first and second ends; said first end of said first lever being rigidly connected to said first choke flap; g. a second lever having first and second ends; h. means for jointedly connecting said first end of said second lever to said second choke flap; i. abutment means positioned between said first end of said second lever and said second choke flap for determining a maximum angl between said second choke flap and said second lever; j. a first spring connected to said second choke flap for urging the same away from said second lever towards said maxmum angle; k. a third lver having two ends being jointedly connected to the respective second ends of said first and second levers; a second spring connected to said first choke flap for directly urging the latter towards said closed position and for indirectly urging said second choke flap into said closed position by said first, second and third levers; and m. means for so arranging said choke flaps with respect to one another that in a closed position of said choke flaps said first choke flap overlaps, with its said second edge zone, the second edge zone of said second choke flap for allowing pivotal motion of said second choke flap relative to said second lever against the force of said first spring beyond said closed position in response to backlash pressures in said flow passage.

Claim 9

A carburetor as defined in claim 6, said choke flaps, when in their closed position, meet in a dowstream-pointing angle.

Claim 10

A carburetor as defined in claim 7, said first, second and third levers being disposed in said flow passage upstream of said choke flaps in the closed position thereof.

Claim 11

A carburetor as defined in claim 8, wherein at least a portion of a linkage system constituted by said first, second and third levers is situated in a space bounded by said choke flaps in their closed position.

Claim 12

A carburetor as defined in claim 7, wherein during normal operation of said choke means the angle defined between said first lever and said first choke flap is different in magnitude from the angle defined between said second lever and said second choke flap.

Claim 13

A carburetor as defined in claim 7, wherein in the closed position of said choke flaps said first lever extends from said first choke flap in a first direction and said second lever extends from said second choke flap in a second direction; one of said first and second directions having a directional component pointing upstream, the other of said first and second directions having a directional component pointing downstream.