Vacuum controlled ignition timing apparatus for internal combustion engine

Claim 2

For use with an internal combustion engine connected to drive a vehicle, the engine having an intake passage for an air-fuel mixture and provided with a throttle valve, the improvement comprising, in combination: a vacuum line communicating with said intake passage downstream from said throttle valve, a three-way valve connected to said vacuum line, means including a movable member for controlling the ignition timing of said engine, a vacuum responsive device including a flexible diaphragm connected to said member, walls forming a spark advance chamber on one side of said diaphragm and forming a spark retard chamber on the other side of said diaphragm, a first conduit connecting said three-way valve to said spark advance chamber, a second conduit connecting said three-way valve to said spark retard chamber, means for moving said three-way valve in response to the vehicle velocity to connect said vacuum line to said first conduit when the vehicle velocity is above a predetermined valve or to said second conduit when the vehicle velocity is below said predetermined valve, means for venting said spark retard chamber through a restricted passage when the spark retard chamber pressure exceeds the pressure of said spark advance chamber, and for venting said spark advance chamber through a restricted passage when the spark advance chamber pressure exceeds the pressure of said spark retard chamber and a valve responsive to engine temperature acting to close said vacuum line when the engine temperature falls below a predetermined value.

Claim 3

For use with an internal combustion engine connected to drive a vehicle, the engine having an intake passage for an air-fuel mixture and provided with a throttle valve, the improvement comprising, in combination: a vacuum line communicating with said intake passage downstream from said throttle valve, a three-way valve connected to said vacuum line, means including a movable member for controlling the ignition timing of said engine, a vacuum responsive device including a flexible diaphragm connected to said member, walls forming a spark advance chamber on one side of said diaphragm and forming a spark retard chamber on the other side of said diaphragm, a first conduit connecting said three-way valve to said spark advance chamber, a second conduit connecting said three-way valve to said spark retard chamber, electromagnetic means for moving said three-way valve to connect said vacuum line to either said first conduit or to said second conduit, a valve responsive to engine temperature acting to close said vacuum line when the engine temperature falls below a predetermined value, means for venting said spark retard chamber through a restricted passage when the spark retard chamber pressure exceeds the pressure of said spark advance chamber, and for venting said spark advance chamber through a restricted passage when the spark advance chamber pressure exceeds the pressure of said spark retard chamber, and an electric circuit for operation of said electromagnetic means, and circuit including a switch sensitive to vehicle velocity and acting to de-energize said electromagnetic means when the vehicle velocity exceeds a predetermined value.

Claim 4

For use with an internal combustion engine connected to drive a vehicle, the engine having an intake passage for an air-fuel mixture and provided with a throttle valve, the improvement comprising, in combination: a vacuum line communicating with said intake passage downstream from said throttle valve, a three-way valve connected to said vacuum line, means including a movable member for controlling the ignition timing of said engine, a vacuum responsive device including a flexible diaphragm connected to said member, walls forming a spark advance chamber on one side of said diaphragm and forming a spark retard chamber on the other side of said diaphragm, a first conduit connecting said three-way valve to said spark advance chamber, a second conduit connecting said three-way valve to said spark retard chamber, electromagnetic means for moving said three-way valve to connect said vacuum line to either said first conduit or to said second conduit, a valve responsive to engine temperature acting to close said vacuum line when the engine temperature falls below a predetermined value, means for venting said spark retard chamber through a restricted passage when the spark retard chamber pressure exceeds the pressure of said spark advance chamber, and for venting said spark advance chamber through a restricted passage when the spark advance chamber pressure exceeds the pressure of said spark retard chamber, and an electric circuit for operation of said electromagnetic means, and circuit including a switch sensitive to vehicle velocity and acting to de-energize said electromagnetic means when the vehicle velocity exceeds a predetermined value.