Transient brake application upon accelerator release

• US 3,891,071 A
• Filed: 12/10/1973
• Issued: 06/24/1975
• Est. Priority Date: 12/10/1973
• Status: Expired due to Term

• Current Assignee: BorgWarner Incorporated
• Original Assignee: John J. Tuzson
• Inventors: Tuzson, John J.
• Primary Examiner(s): Wyche, Benjamin W.
• Application Number:
  US05/423,382
• Time in Patent Office: 561 Days
• Field of Search: 192/3R,3TR,3S
• US Class Current: 477/202
• CPC Class Codes: B60T 11/103 in combination with other control devices conjoint control of brake system and at least another sub-unit B60W10/188
• CPC Class Codes: B60T 13/52 indirect, i.e. vacuum booster units
• CPC Class Codes: B60W 10/04 including control of propulsion units
• CPC Class Codes: B60W 10/18 including control of braking systems

Abstract

A brake control for a limited brake application of short duration when the accelerator pedal of a vehicle is released suddenly, with the control including a dashpot actuated by the accelerator pedal, a vent valve activated by vacuum created in the dashpot and a brake pedal actuator communicating with a suitable vacuum source acting on both sides of a diaphragm therein. The actuator is operatively connected to the brake pedal, and the vacuum line to one side of the diaphragm has an orifice or restriction therein so that when the vent valve opens, the one side of the diaphragm is vented slowly to atmospheric pressure because of the orifice while the other side is immediately vented to atmosphere pressure, thus causing the actuator to provide a braking pressure which fades after a brief delay.

Claims

1. A transient brake control system for an automotive vehicle having an engine fuel feeding system and a braking system, comprising a control means for the engine fuel feeding system movable between an engine idling position and engine speed-up positions, a separate Control means for the vehicle braking system, an actuator for the braking system including a diaphragm operatively connected to said brake control means, a pair of chambers formed on opposite sides of the diaphragm and communicating with a source of vacuum to equalize the pressure in both chambers, a vent valve adapted to be actuated by operation of said engine control means and including a housing having an ambient air inlet at one end, a diaphragm in the housing separating the ends thereof, and a valve member secured to the diaphragm and normally closing said inlet, a vacuum conduit communicating with said vacuum source and extending between one of said chambers and said vent valve, and a branch line extending between the opposite chamber and said conduit and having a restricted orifice therein, said vacuum conduit communicating with said vent valve adjacent said ambient air inlet.

2. A transient brake control system as set forth in claim 1, including a dashpot operatively connected to said engine control means, a conduit extending between said dashpot and the opposite end of the valve housing, and a restricted ambient air inlet communicating with said conduit.

3. A transient brake control system as set forth in claim 2 in which said dashpot includes a reciprocable piston operatively connected to said engine control means.

4. A transient brake control system for an automotive vehicle having an engine fuel feeding system and a braking system, comprising a control means for the engine fuel feeding system movable between an engine idling position and engine speed-up positions, a separate control means for the vehicle braking system, an actuator operatively connected to said brake control means and including a pair of chambers formed on opposite sides of a diaphragm and communicating with a source of vacuum to equalize the pressure in both chambers and a piston in one chamber of said actuator operatively connected to said diaphragm and having a rod operatively connected to said brake control means, a dashpot operatively connected to said engine control means, a vent valve adapted to be actuated by operation of said dashpot, a vacuum conduit communicating with said source of vacuum and extending between said one chamber and said vent valve, and a branch line extending between the opposite chamber in the actuator and said conduit and having a restricted orifice therein.

5. A transient brake control system as set forth in claim 4, in which said vent valve includes a diaphragm actuated valve member and an ambient air inlet normally closed by said valve member, said vacuum conduit communicating with said vent valve adjacent the ambient air inlet.

6. A transient brake control system as set forth in claim 5, including a by-pass in said branch conduit around said restricted orifice, and a check valve in said by-pass preventing flow through said by-pass toward said actuator.

7. A transient brake control system as set forth in claim 6, in which said dashpot includes a reciprocable piston operatively connected with said engine control means and a conduit extending between said dashpot and the side of the vent valve diaphragm opposite to said inlet, and an ambient air inlet having a restricted orifice communicating with said last-named conduit.

8. A transient brake control system as set forth in claim 7, including resilient means acting to yieldably retract the engine control means to the engine idling position.

9. A transient brake control system as set forth in claim 8, in which the gradual release of said engine control means from an engine speed-up position to the engine idling position provides gradual movement of the piston in the dashpot, whereas a sudden release of said engine control means allows a sudden movement of the dashpot piston creating a vacuum behind the vent valve diaphragm to open said ambient air inlet, which in turn vents the actuator chambers to atmospheric pressure, said restricted orifice in said branch line creating a pressure imbalAnce in the actuator causing the piston therein to actuate the brake control means.

10. A transient brake control system as set forth in claim 9, in which said actuator action on said brake control means is momentary and then gradually fades as the restricted orifice in said branch line allows a gradual equalization of pressure in the two chambers of the actuator.

11. A transient brake control system for an automotive vehicle having an engine fuel feeding system and a braking system, comprising a control means for the engine fuel feeding system movable between an engine idling position and engine speed-up positions, a separate control means for the vehicle braking system, an actuator for the braking system including a diaphragm operatively connected to said brake control means, a pair of chambers formed on opposite sides of the diaphragm and communicating with a source of vacuum to equalize the pressure in both chambers, a vent valve adapted to be actuated by operation of said engine control means, a vacuum conduit communicating with said vacuum source and extending between one of said chambers and said vent valve, a branch line extending between the opposite chamber and said conduit and having a restricted orifice therein, a by-pass in said branch line around the restricted orifice, and a check valve in said by-pass preventing flow through said by-pass toward said opposite chamber.