Ambient temperature regulated choke

Claim 2

A carburetor for an internal combustion engine comprising a carburetor body having an induction passage for delivery of an air fuel mixture to the intake manifold of the engine as controlled by a throttle valve, a choke shaft journalled in said body, a choke valve secured off-center on said choke shaft and disposed in said induction passage, a first lever means fixed to said choke shaft for rotation therewith, a second lever means rotatably supported on said choke shaft, a choke coil housing positioned in thermal relation to the engine, a shaft journalled in said choke coil housing, a temperature responsive bi-metal choke coil fixed at one end to said shaft and at its other end operatively connected to said first lever means to urge said choke valve in a closing direction with a force related to engine temperature, spring means positioned to normally rotatively bias said shaft in a direction to load said choke coil, a first lost motion connection between said shaft and said second lever means and, a second lost motion connection between said second lever means and said first lever means to effect rotation of said shaft in a direction to unlOad said choke coil as a function of choke valve opening.

Claim 3

A carburetor according to claim 1 including a control means responsive to intake manifold pressure downstream of said throttle valve and having a linearly moving plunger movable as a function of intake manifold pressure, said second lost motion connection including a link connected to said plunger and pivotably connected to said second lever means.

Claim 4

A carburetor according to claim 2 wherein said control means comprises a housing, a diaphragm in said housing to form therewith an expansible chamber, said plunger being connected at one end to said diaphragm and a conduit connecting said expansible chamber to said induction passage downstream of said throttle valve and spring means positioned to bias said diaphragm against said intake manifold pressure.

Claim 5

A carburetor according to claim 2 further including an ambient temperature responsive element mounted adjacent said control means, and a cam means connected to said temperature responsive element for movement thereby and positioned to engage said plunger to limit its linear movement as a function of ambient temperature as sensed by said temperature responsive element.

Claim 6

A carburetor according to claim 4 wherin said temperature responsive element is a bi-metal coil fixed at one end relative to said control means and having its other end engaging said cam means, said cam means being slidably mounted on said control means for movement at a right angle to said plunger, said cam means having cam steps of stepped incremental heights thereon, the cam step of lowest height engaging the plunger at high ambient temperature while the cam step of greatest height engaging the plunger at low ambient temperature.

Claim 7

A charge forming device for an internal combustion engine of the type having a body with an induction passage connected to the intake manifold of the engine and having a choke valve secured on a choke shaft and rotatably disposed in the induction passage, means for automatically controlling the operation of the choke valve as a function of engine temperature and ambient air temperature, said means including a first lever means, having an arcuate slot therein, fixed to said choke shaft for rotation therewith, a second lever means rotatably mounted on said choke shaft adjacent said first lever means, a choke coil housing positioned in thermal relation to the engine, a shaft journalled in said choke coil housing, a termperature responsive choke coil in said choke coil housing fixed at one end to said shaft and at its other end operatively connected to said first lever means to urge said choke valve in a closing direction, a third lever means, having an arcuate slot therein, fixed to said shaft for rotation therewith, spring means positioned to normally rotate said shaft in a direction to load said choke coil, a first link pivotally connected at one end to said second lever means and at its other end extending through said arcuate slot in siad third lever means, a control means responsive to intake manifold pressure and having a diaphragm movable as a function of intake manifold pressure, a plunger connected at one end to said diaphragm, a second link pivotally connected to the opposite end of said plunger with its opposite end of said second link pivotally connected to said second lever and extending into the arcuate slot of said first lever means, a temperature responsive element mounted adjacent said control means and, a cam means connected to said ambient temperature responsive element for movement thereby in position to engage said plunger to limit its linear movement.

Claim 8

A charge forming device for an internal combustion engine of the type having a body with an induction passage connected to the intake manifold of the engine and having a choke valve secured on a choke shaft and rotatably disposed in the induction passage, means for automatically controlling the operation of the choke valve as a function of engine temperature and ambient air temperature, said means including a first lever means, having an arcuate slot therein, fixed to said choke shaft for rotation therewith, a second lever means rotatably mounted on said choke shaft adjacent said first lever means, a choke coil housing positioned in thermal relation to the engine, a shaft journalled in said choke coil housing, a termperature responsive choke coil in said choke coil housing fixed at one end to said shaft and at its other end operatively connected to said first lever means to urge said choke valve in a closing direction, a third lever means, having an arcuate slot therein, fixed to said shaft for rotation therewith, spring means positioned to normally rotate said shaft in a direction to load said choke coil, a first link pivotally connected at one end to said second lever means and at its other end extending through said arcuate slot in siad third lever means, a control means responsive to intake manifold pressure and having a diaphragm movable as a function of intake manifold pressure, a plunger connected at one end to said diaphragm, a second link pivotally connected to the opposite end of said plunger with its opposite end of said second link pivotally connected to said second lever and extending into the arcuate slot of said first lever means, a temperature responsive element mounted adjacent said control means and, a cam means connected to said ambient temperature responsive element for movement thereby in position to engage said plunger to limit its linear movement.

Claim 9

In a carburetor for an internal combustion engine, the carburetor including a body having an induction passage controlled by a choke valve mounted on a choke shaft journalled in the body, a first lever means fixed to said choke shaft, a second lever means rotatively mounted on said choke shaft, a lost motion connection between said first lever means and said second lever means, a thermosTat choke coil operatively connected at one end to said first lever and positioned in thermal relation to the engine to move the choke valve toward a closed position at low engine temperatures, means pivotally connected at one end to said second lever and connected at its opposite end through a lost motion connection to said thermostat choke coil to vary the rate at which said choke valve is actuated by said thermostat choke coil by unloading said thermostat choke coil as a function of choke valve opening angle, a vacuum break means operative as a function of engine intake vacuum operatively connected to said second lever means to effect opening of said choke valve upon increase in engine intake vacuum and an ambient temperature actuated stepped cam operatively connected to said vacuum break means to limit opening of said choke valve by said vacuum break means as a function of ambient temperatures.

Claim 10

In a carburetor for an internal combustion engine, the carburetor including a body having an induction passage controlled by a choke valve mounted on a choke shaft journalled in the body, a first lever means fixed to said choke shaft, a second lever means rotatively mounted on said choke shaft, a lost motion connection between said first lever means and said second lever means, a thermosTat choke coil operatively connected at one end to said first lever and positioned in thermal relation to the engine to move the choke valve toward a closed position at low engine temperatures, means pivotally connected at one end to said second lever and connected at its opposite end through a lost motion connection to said thermostat choke coil to vary the rate at which said choke valve is actuated by said thermostat choke coil by unloading said thermostat choke coil as a function of choke valve opening angle, a vacuum break means operative as a function of engine intake vacuum operatively connected to said second lever means to effect opening of said choke valve upon increase in engine intake vacuum and an ambient temperature actuated stepped cam operatively connected to said vacuum break means to limit opening of said choke valve by said vacuum break means as a function of ambient temperatures.

Claim 11

A carburetor for an internal combustion engine comprising a carburetor body having an induction passage connected to the intake manifold of the engine, a choke shaft journalled in said body, a choke valve secured to said choke shaft and disposed in said induction passage, a thermostat choke coil positioned in thermal relation to the engine and operatively connected at one end to said choke shaft to move said choke valve toward a closed position at low engine temperatures, a vacuum break control means responsive to intake manifold pressure operatively connected to the intake manifold of the engine, a plunger secured at one end for movement by said control means, link means including a lost motion connection connecting said plunger to said choke shaft to effect opening of said choke valve upon increase in engine intake vacuum against the biasing action of said thermostat choke coil, and an ambient temperature actuated stepped cam operatively connected to said plunger to limit movement of said plunger to thereby limit opening of said choke valve as a function of ambient temperature, said thermostat choke coil being operatively connected at its other end to a rotatable shaft, spring means operatively connected to said shaft to rotate said shaft in one direction to effect loading of said thermostat choke coil and link means including a lost motion connection connected at one end to said shaft and at its other end through said lost motion connection to said choke shaft to effect unloading of said thermostat choke coil as a function of choke valve opening angle.

Claim 12

A carburetor for an internal combustion engine comprising a carburetor body having an induction passage connected to the intake manifold of the engine, a choke shaft journalled in said body, a choke valve secured to said choke shaft and disposed in said induction passage, a thermostat choke coil positioned in thermal relation to the engine and operatively connected at one end to said choke shaft to move said choke valve toward a closed position at low engine temperatures, a vacuum break control means responsive to intake manifold pressure operatively connected to the intake manifold of the engine, a plunger secured at one end for movement by said control means, link means including a lost motion connection connecting said plunger to said choke shaft to effect opening of said choke valve upon increase in engine intake vacuum against the biasing action of said thermostat choke coil, and an ambient temperature actuated stepped cam operatively connected to said plunger to limit movement of said plunger to thereby limit opening of said choke valve as a function of ambient temperature, said thermostat choke coil being operatively connected at its other end to a rotatable shaft, spring means operatively connected to said shaft to rotate said shaft in one direction to effect loading of said thermostat choke coil and link means including a lost motion connection connected at one end to said shaft and at its other end through said lost motion connection to said choke shaft to effect unloading of said thermostat choke coil as a function of choke valve opening angle.