Vehicle hydraulic brake booster system and method

Patent metadata

Field	Value
Publication number	US-9868427-B2
Application number	US-201615227399-A
Country	US
Kind code	B2
Filing date	Aug 3, 2016
Priority date	Oct 14, 2015
Publication date	Jan 16, 2018
Grant date	Jan 16, 2018

Abstract

A vehicle brake booster system includes a reservoir, a pump, and a brake booster. The brake booster includes an input member adapted to receive a manual braking input force and an output member adapted to apply a braking output force to a master cylinder. A supply line couples the pump to the brake booster, and a return line couples an outlet of the brake booster to the reservoir. A flow of hydraulic fluid pumped to the brake booster provides a boost factor by which the braking output force exceeds the braking input force. The brake booster is hydraulically lockable by a first valve in the supply line and a second valve in the return line such that when the first and second valves are closed, a quantity of hydraulic fluid is trapped within the brake booster to maintain operation of the brake booster without continued operation of the pump.

First claim

What is claimed is:

1. A vehicle brake booster system comprising:
a reservoir;
a pump operable to drive a hydraulic fluid from the reservoir;
a brake booster including an input member adapted to receive a manual braking input force from a vehicle operator and an output member adapted to apply a braking output force to a master cylinder;
a supply line coupling an outlet of the pump to an inlet of the brake booster;
a return line coupling an outlet of the brake booster to the reservoir, and
a steering gear in communication with the brake booster via a connection line and with the reservoir via a steering gear return line,
wherein a flow of hydraulic fluid pumped to the brake booster by the pump provides a boost factor by which the braking output force exceeds the braking input force;
wherein the brake booster is hydraulically lockable by a first valve in the supply line and a second valve in the return line such that when the first and second valves are closed, a quantity of hydraulic fluid is trapped within the brake booster to maintain operation of the brake booster without continued operation of the pump, and
wherein a third valve in the connection line is operable to lock the quantity of hydraulic fluid within the brake booster when the pump is non-operational.

2. The vehicle brake booster system of claim 1 , wherein the first valve is a one-way check valve operable to prevent fluid from draining from the brake booster, through the supply line, and to the pump.

3. The vehicle brake booster system of claim 1 , wherein the second valve is a solenoid valve operable to prevent fluid from draining from the brake booster, through the return line, and to the reservoir.

4. The vehicle brake booster system of claim 3 , wherein the solenoid valve is biased to an open position and is electrically actuatable to a closed position.

5. The vehicle brake booster system of claim 1 , wherein the third valve is a solenoid valve operable to prevent fluid from draining from the brake booster, through the connection line, and to the steering gear.

6. The vehicle brake booster system of claim 1 , wherein the solenoid valve is biased to an open position and is electrically actuatable to a closed position.

7. The vehicle brake booster system of claim 1 , further comprising a controller electrically coupled to the second valve and programmed to actuate the second valve closed when the pump is not driving the hydraulic fluid from the reservoir.

8. A vehicle comprising:
a plurality of drive wheels;
an engine for powering the drive wheels to move the vehicle along the ground;
a brake booster system including:
a reservoir;
a pump operable to drive a hydraulic fluid from the reservoir;
a brake booster;
a supply line coupling an outlet of the pump to an inlet of the brake booster; and
a return line coupling an outlet of the brake booster to the reservoir; and

a steering gear operable to reduce a required steering effort of the vehicle, the steering gear in communication with the brake booster via a connection line and with the reservoir via a steering gear return line,
wherein the brake booster includes an input member adapted to receive a manual braking input force from a vehicle operator and an output member adapted to apply a braking output force to a master cylinder,
wherein a flow of hydraulic fluid pumped to the brake booster by the pump provides a boost factor by which the braking output force exceeds the braking input force, and
wherein the brake booster is hydraulically lockable by a first valve in the supply line and a second valve in the return line such that when the first and second valves are closed, a quantity of hydraulic fluid is trapped within the brake booster to maintain operation of the brake booster without continued operation of the pump, and
wherein a third valve in the connection line is operable to lock the quantity of hydraulic fluid within the brake booster when the pump is non-operational.

9. The vehicle of claim 8 , wherein the pump is non-operational when the engine is turned off.

10. The vehicle of claim 9 , wherein the second valve is a normally open solenoid valve operable to prevent fluid from draining from the brake booster, through the return line, and to the reservoir when the pump is non-operational.

11. The vehicle of claim 10 , wherein the return line is provided with a check valve in parallel with the second valve, the check valve operable to allow hydraulic fluid above a threshold pressure value from the brake booster to the reservoir regardless of the position of the second valve.

12. The vehicle of claim 8 , further comprising a controller having a preprogrammed stop/start routine for automatically stopping and re-starting the engine without direct initiation by a human operator, and wherein the controller is programmed to actuate the second valve into a closed position to lock a quantity of hydraulic fluid within the brake booster in response to an automatic engine stoppage of the stop/start routine.

13. The vehicle of claim 12 , wherein the controller is programmed to unlock the locked quantity of hydraulic fluid in response to subsequent automatic engine re-starting of the stop/start routine.

Assignees

• Bosch Gmbh Robert

Inventors

• Penninger William John
• Mcclain Richard Becker

Classifications

• B60T13/168 Primary

  Arrangements for pressure supply · CPC title

• B60T8/40

  comprising an additional fluid circuit including fluid pressurising means for modifying the pressure of the braking fluid, e.g. including wheel driven pumps for detecting a speed condition, or pumps which are controlled by means independent of the braking system · CPC title

• B60T13/143

  Master cylinder mechanically coupled with booster · CPC title

• B60T17/16

  Locking of brake cylinders · CPC title

• B60T13/18

  with control of pump output delivery {, e.g. by distributor valves (B60T13/167 takes precedence)} · CPC title