Carburetor for an internal combustion engine

Claim 2

A carburetor for an internal combustion engine of an automotive vehicle, the vehicle being equipped with a transmission, the carburetor comprising: (a) primary and secondary barrels, the primary barrel comprising, (1) a primary air intake passage, (2) a primary venturi arranged in the primary air intake passage, (3) a primary throttle valve arranged in the primary air intake passsage downstream of the primary venturi, the secondary barrel comprising, (4) a secondary air intake passage, (5) a secondary venturi arranged in the secondary air intake passage, (6) a secondary throttle valve arranged in the secondary air intake passage downstream of the secondary venturi; (b) a vacuum responsive actuator connected to the secondary throttle valve to operate the same; (c) a passageway opening to the primary and secondary venturis for obtaining a resultant of the primary and secondary venturi vacuums and introducing the resultant vacuum into the actuator so that the secondary throttle valve will be opened as the resultant vacuum rises; (d) a sensor for detecting whether a low-speed gear is engaged in the transmission; and (e) a valve responsive to the sensor for controlling the introduction of the resultant vacuum into the actuator; whereby the secondary throttle valve is closed irrespective of the resultant vacuum when the low-speed gear is engaged in the transmission.

Claim 3

A carburetor as defined by claim 1, further comprising a second sensor for detecting whether the primary throttle valve is opened wider than a predetermined degree of opening, the control valve also responsive to the second sensor, whereby the secondary throttle valve is closed irrespective of the resultant vacuum when the low-speed gear is engaged and also the primary throttle valve is opened wider than the predetermined degree of opening.

Claim 4

A carburetor as defined by claim 2, wherein the control valve interposed in the passageway is adapted to selectively introduce the resultant vacuum or atmospheric pressure into the actuator so that the secondary throttle valve will be closed when the control valve introduces atmospheric pressure into the actuator.

Claim 5

A carburetor of an internal combustion engine of an automotive vehicle, comprising: (a) primary and secondary barrels, the primary barrel comprising, (1) a primary air intake passage, (2) a primary venturi arranged in the primary air intake passage, (3) a primary throttle valve arranged in the primary air intake passage downstream of the primary venturi, the secondary barrel comprising, (4) a secondary air intake passage, (5) a secondary venturi arranged in the secondary air intake passage, (6) a secondary throttle valve arranged in the secondary air intake passage downstream of the secondary venturi; (b) a vacuum responsive actuator connected to the secondary throttle valve to operate the same; (c) a passageway opening to the primary and secondary venturis for obtaining the resultant of the primary and secondary venturi vacuums and introducing the resultant vacuum into the actuator so that the secondary throttle valve will be opened as the resultant vacuum rises; (d) a diaphragm device for obstructing the opening of the secondary throttle valve, while not interfering with the closing of the secondary throttle valve.

Claim 6

A carburetor of an internal combustion engine of an automotive vehicle, comprising: (a) primary and secondary barrels, the primary barrel comprising, (1) a primary air intake passage, (2) a primary venturi arranged in the primary air intake passage, (3) a primary throttle valve arranged in the primary air intake passage downstream of the primary venturi, the secondary barrel comprising, (4) a secondary air intake passage, (5) a secondary venturi arranged in the secondary air intake passage, (6) a secondary throttle valve arranged in the secondary air intake passage downstream of the secondary venturi; (b) a vacuum responsive actuator connected to the secondary throttle valve to operate the same; (c) a passageway opening to the primary and secondary venturis for obtaining the resultant of the primary and secondary venturi vacuums and introducing the resultant vacuum into the actuator so that the secondary throttle valve will be opened as the resultant vacuum rises; (d) a diaphragm device for obstructing the opening of the secondary throttle valve, while not interfering with the closing of the secondary throttle valve.

Claim 7

A carburetor as defined by claim 4, wherein the diaphragm device comprises a casing, a diaphragm defining a chamber within the casing, the diaphragm subjected to the atmosphere on the surface opposite to the chamber, the diaphragm disconnectably engaging with the secondary throttle valve, the chamber opening to the atmosphere through an orifice, a return spring biasing the diaphragm in the direction closing the secondary throttle valve.

Claim 8

A carburetor for an internal combustion engine of an automotive vehicle, comprising: (a) primary and secondary barrels, the primary barrel comprising, (1) a primary air intake passage, (2) a primary venturi arranged in the primary air intake passage, (3) a primary throttle valve arranged in the primary air intake passage downstream of the primary venturi, the secondary barrel comprising, (4) a secondary air intake passage, (5) a secondary venturi arranged in the secondary air intake passage, (6) a secondary throttle valve arranged in the secondary air intake passage downstream of the secondary venturi; (b) a pressure responsive actuator comprising, (1) a casing, (2) first and second diaphragms dividing the inside of the casing into three chambers, the first diaphragm being of a lower effective area than the second diaphragm, the first chamber being formed by the casing and the first diaphragm, the first chamber opening to the atmosphere through an orifice and through a check valve parallel to the orifice, the second chamber being formed between the first and second diaphragms and the casing, the second chamber having an inlet, the third chamber being formed by the second diaphragm and the casing, and the third chamber opening to the atmosphere, (3) a rod fixed to the first and second diaphragms, the rod connected to the secondary throttle valve to drive the same, (4) a return spring biasing the first diaphragm in the direction closing the secondary throttle valve; and (c) a passageway opening to the primary and secondary venturis for obtaining the resultant of the primary and secondary venturi vacuums and introducing the resultant vacuum into the second chamber via the inlet so that the secondary throttle valve will be opened as the resultant vacuum rises to displace the first and second diaphragms; whereby when the secondary throttle valve is opened, the check valve is closed to obstruct the displacement of the first diaphragm and thus reduce the rate of opening of the secondary throttle valve.

Claim 9

A carburetor for an internal combustion engine of an automotive vehicle, comprising: (a) primary and secondary barrels, the primary barrel comprising, (1) a primary air intake passage, (2) a primary venturi arranged in the primary air intake passage, (3) a primary throttle valve arranged in the primary air intake passage downstream of the primary venturi, the secondary barrel comprising, (4) a secondary air intake passage, (5) a secondary venturi arranged in the secondary air intake passage, (6) a secondary throttle valve arranged in the secondary air intake passage downstream of the secondary venturi; (b) a pressure responsive actuator comprising, (1) a casing, (2) first and second diaphragms dividing the inside of the casing into three chambers, the first diaphragm being of a lower effective area than the second diaphragm, the first chamber being formed by the casing and the first diaphragm, the first chamber opening to the atmosphere through an orifice and through a check valve parallel to the orifice, the second chamber being formed between the first and second diaphragms and the casing, the second chamber having an inlet, the third chamber being formed by the second diaphragm and the casing, and the third chamber opening to the atmosphere, (3) a rod fixed to the first and second diaphragms, the rod connected to the secondary throttle valve to drive the same, (4) a return spring biasing the first diaphragm in the direction closing the secondary throttle valve; and (c) a passageway opening to the primary and secondary venturis for obtaining the resultant of the primary and secondary venturi vacuums and introducing the resultant vacuum into the second chamber via the inlet so that the secondary throttle valve will be opened as the resultant vacuum rises to displace the first and second diaphragms; whereby when the secondary throttle valve is opened, the check valve is closed to obstruct the displacement of the first diaphragm and thus reduce the rate of opening of the secondary throttle valve.