Brake system controlled choke valve

Claim 1

In a vehicle including an internal combustion engine providing a source of engine vacuum and having an air induction passage, an operator-controlled throttle valve pivotably mounted in the air induction passage to normally regulate airflow to the engine, a choke valve pivotably mounted on a choke shaft upstream of the throttle valve in the air induction passage; and a vacuum boosted power braking system including a brake pedal, hydraulic pump means hydraulically connected to the set of vehicle wheel brakes, and a vacuum booster unit connected to the hydraulic pump means, the vacuum booster unit having a first pressure chamber, a second pressure chamber, and air valve means actuatable on actuation of the brake pedal, the first pressure chamber being connected to the source of engine vacuum and the second pressure chamber being selectively connectable by the air valve means to the first pressure chamber when the brake pedal is not actuated and to the atmosphere when the brake pedal is actuated; a. differential fluid presSure actuated power means including a housing and a diaphragm means, said diaphragm means separating said housing into a first chamber and a second chamber, said first chamber being operatively connected to communicate with the second pressure chamber of the vacuum booster unit and said second chamber being connected to communicate with the atmosphere; b. lost motion linkage means operatively connecting said diaphragm means of said differential fluid pressure actuated power means and said choke shaft and including a first lever fixed to one end of said choke shaft and a second lever loosely carried by said shaft at said one end and rotatable relative thereto between a first position and a second position, said first lever having an arcuate slot therein and said second lever having a tab slidably received in said slot and operative to engage said first lever at one end of said slot whereby, with said brake pedal not actuated, said diaphragm means positions said second lever in said first position and said slot permits said first lever to move relative to said second lever as said first lever follows the movement of the choke valve between a fully open position and a closed position; and c. spring means operatively connected to said lost motion linkage means and operative when said brake pedal is actuated to effect movement of said second lever from said first position to said second position as said first chamber of said differential fluid pressure actuated power means is placed in communication with the atmosphere whereby said tab of said second lever engages said first lever at one end of said arcuate slot to cause said first lever to effect movement of said choke valve through said choke shaft to a partially closed position offset slightly in the choke valve opening direction from the closed position.