Carburetor cold enrichment control

Claim 2

A cold engine enrichment control for use in a carburetor having an air/fuel induction passage open at one end to clean air at essentially atmospheric pressure and connected to an engine intake manifold at the opposite other end to be subject to the changes in engine vacuum, a throttle valve mounted for movement across the other end between closed and fully open positions to control the flow of fuel and air through the passage, and a choke valve anterior of the throttle valve mounted for movement across the one end between closed and open inoperative positions to control the flow of air into the passage, the control including first means operably connected to the choke valve and operable above a predetermined temperature upon the engine attaining a running condition to move the choke valve to an open inoperative position to increase airflow and decrease emissions, and second temperature responsive means operably positioned in the path of closing movement of the throttle valve and variably movable as a function of temperature changes independently of the first means to restrict the closing movement of the throttle valve to maintain the throttle valve open to a beyond normal engine idle speed position to increase the flow of the air/fuel mixture, to prevent engine stallings.

Claim 3

A control as in claim 1, the first means including an engine vacuum servo operable to pull open the choke valve.

Claim 4

A control as in claim 1, the second means including a throttle shaft, a lever secured to the throttle shaft, a fast idle cam rotatably mounted on the shaft and having an abutment surface with varying radial extent steps engagable individually by the lever, and a temperature responsive member effecting rotation of the cam as a function of temperature changes to determine the open position of the throttle valve.

Claim 5

A control as in claim 3, the first means comprising an engine vacuum controlled servo operable to pull open the choke valve.

Claim 6

A control as in claim 4, the first means also including a second engine vacuum actuated servo to move the choke valve to an initial slightly open position less than the inoperative position prior to the first servo moving the choke valve.

Claim 7

A control as in claim 3, including a bimetallic temperature responsive coiled spring having an end rotatably movable as a function of temperature changes, a member rotated by the spring and engaged by the fast idle cam to restrict the rotative movement of the cam as a function of the movement of the spring.

Claim 8

A control as in claim 6, including means on the first means interacting with the member to prevent return movement at times of the first means to a closed choke position.

Claim 9

A control as in claim 7, the first means comprising an engine vacuum actuated servo operable to pull open the choke valve.

Claim 10

A control as in claim 8, the first means also including a second engine vacuum actuated servo to move the choke valve to an initial slightly open position less than the inoperative position prior to the first servo moving the choke valve.

Claim 11

A control as in claim 9, including an engine heat source operably connected to the coiled spring to warm the spring as a function of engine temperature changes.

Claim 12

A cold enrichment control for a carburetor having an air/fuel induction passage open at an air end to air at essentially atmospheric pressure and connected at its opposite engine end to an engine intake manifold to be subject to the changing vacuum levels therein, the air end having a choke valve rotatably mounted for movement across the air end between a closed position and an open position wherein the choke valve is inoperative to restrict the flow of air into the passage, and a throttle valve secured to a shaft rotatably mounted posterior of the choke valve for movement of the throttle valve across the passage between a normal essentially closed engine idle speed position and beyond towards a wide open throttle position to control the volume of flow of an air/fuel mixture through the passage as a function of the position of the throttle valve, the control comprising means operable during cold engine operations to position the choke valve independently of the position of the throttle valve, to improve emissions while minimizing engine stalling, the last mentioned means including, abutment means secured to the throttle shaft, a second shaft, a fast idle cam rotatably mounted on the second shaft and having an edge formed with steps progressively greater in radial extent than one which when engaged by the abutment means would permit closure of the throttle valve to the normal engine idle speed position, whereby the throttle valve will be progressively opened beyond the latter position as a function of the particular step engaged by the abutment means, spring means biasing the abutment means and throttle valve towards a closed position and into individual engagement with one of the steps, a thermostatically responsive coiled spring operatively rotating the fast idle cam to positions operatively moving the throttle valve to positions progressively more open than the normal idle speed position as a function of decreases in temperature from a predetermined level, first means operatively connected to the choke valve, engine vacuum actuated servo means connected to the first means to open the choke valve to the inoperative position upon the engine attaining a normal running condition, and means providing a limited unidirectional interconnection between the fast idle cam and choke valve permitting opening of the choke valve and operation of the fast idle cam independent of each other.

Claim 13

A cold enrichment control for a carburetor having an air/fuel induction passage open at an air end to air at essentially atmospheric pressure and connected at its opposite engine end to an engine intake manifold to be subject to the changing vacuum levels therein, the air end having a choke valve rotatably mounted for movement across the air end between a closed position and an open position wherein the choke valve is inoperative to restrict the flow of air into the passage, and a throttle valve secured to a shaft rotatably mounted posterior of the choke valve for movement of the throttle valve across the passage between a normal essentially closed engine idle speed position and beyond towards a wide open throttle position to control the volume of flow of an air/fuel mixture through the passage as a function of the position of the throttle valve, the control comprising means operable during cold engine operations to position the choke valve independently of the position of the throttle valve, to improve emissions while minimizing engine stalling, the last mentioned means including, abutment means secured to the throttle shaft, a second shaft, a fast idle cam rotatably mounted on the second shaft and having an edge formed with steps progressively greater in radial extent than one which when engaged by the abutment means would permit closure of the throttle valve to the normal engine idle speed position, whereby the throttle valve will be progressively opened beyond the latter position as a function of the particular step engaged by the abutment means, spring means biasing the abutment means and throttle valve towards a closed position and into individual engagement with one of the steps, a thermostatically responsive coiled spring operatively rotating the fast idle cam to positions operatively moving the throttle valve to positions progressively more open than the normal idle speed position as a function of decreases in temperature from a predetermined level, first means operatively connected to the choke valve, engine vacuum actuated servo means connected to the first means to open the choke valve to the inoperative position upon the engine attaining a normal running condition, and means providing a limited unidirectional interconnection between the fast idle cam and choke valve permitting opening of the choke valve and operation of the fast idle cam independent of each other.

Claim 14

A control as in claim 11, the last mentioned means including stop means operatively connected to the fast idle cam and engagable with the first means to control the return movement of the choke valve towards a closed position as a function of temperature changes upon engine shutdown.

Claim 15

A control as in claim 12, including second vacuum actuated servo means operatively connected to the fast idle cam to effect engagement of the first means to crack open the choke valve beyond a closed position in response to engine start-up.