Vehicle motion control apparatus

• US 7,658,454 B2
• Filed: 07/16/2004
• Issued: 02/09/2010
• Est. Priority Date: 07/17/2003
• Status: Expired due to Fees

• Current Assignee: Advics Company Limited (Aisin Corp.)
• Original Assignee: Advics Company Limited (Aisin Corp.)
• Inventors: Yasui, Hideaki, Yogo, Kazutoshi, Kato, Toshihisa
• Primary Examiner(s): Siconolfi; Robert A
• Assistant Examiner(s): SY, MARIANO ONG
• Application Number:
  US10/892,470
• Publication Number:
  US 20050012390A1
• Time in Patent Office: 2,034 Days
• Field of Search: 303/146, 303/140, 303/116.1, 303/116.3, 303/119.1, 303/155, 303/147, 303/148, 303/139, 303/9.62, 701/70, 701/72, 701/78, 180/197
• US Class Current: 303/146
• CPC Class Codes: B60T 8/1755 Brake regulation specially adapted to control the stability of the vehicle, e.g. taking into account yaw rate or transverse acceleration in a curve road vehicle drive control systems for control of driving stability otherwise than by controlling a particular sub-unit B60W30/02
• CPC Class Codes: B60T 8/4872 pump-back systems

Abstract

A proportional pressure difference valve is disclosed between a master cylinder and normally open valves for supplying hydraulic pressure discharged from the master cylinder into wheel brake cylinders, which are connected to normally closed valves for reducing pressure. The normally open valve connected to one of the wheel brake cylinders in one hydraulic circuit is placed in its closed position, and the normally open valve connected to the other one of the wheel brake cylinders is placed in its open position and then the pressure difference valve is controlled on the basis of a monitored vehicle state variable to regulate a pressure difference between the pressure at the side of the master cylinder and the pressure at the side of the normally open valves.

Claims

1. A method for controlling a vehicle motion control apparatus comprising:

wheel brake cylinders operatively associated with wheels of a vehicle, respectively;

a master cylinder connected to said wheel brake cylinders through a dual hydraulic circuit with a pair of wheel brake cylinders included in each hydraulic circuit, said master cylinder discharging a hydraulic braking pressure into each hydraulic circuit in response to operation of a brake pedal;

normally open switching valves each disposed between said master cylinder and each of said pair of wheel brake cylinders, each of said normally open switching valves supplying the hydraulic braking pressure discharged from said master cylinder into each of said pair of wheel brake cylinders when each of said normally open switching valves is placed in an open position thereof;

normally closed switching valves each connected to a passage between each of said normally open switching valves and each of said pair of wheel brake cylinders, each of said normally closed switching valves reducing the hydraulic braking pressure in each of said pair of wheel brake cylinders when each of said normally closed switching valves is placed in an open position thereof;

proportional pressure difference valve means disposed between said master cylinder and said normally open switching valves in each hydraulic circuit, said valve means regulating a pressure difference between the hydraulic pressure at the side of said master cylinder and the hydraulic pressure at the side of said normally open switching valves to be of a desired value;

automatic hydraulic pressure generating means for generating a hydraulic braking pressure independently of said master cylinder and irrespective of operation of said brake pedal, and supplying the hydraulic braking pressure into a passage between said valve means and said normally open switching valves in each hydraulic circuit;

yaw rate detection means for detecting an actual yaw rate of said vehicle;

desired yaw rate setting means for setting a desired yaw rate of said vehicle;

yaw rate deviation calculation means for calculating a deviation between the desired yaw rate set by said desired yaw rate setting means and the actual yaw rate detected by said yaw rate detection means; and

control means for controlling said pressure generating means, said normally open switching valve, said normally closed switching valve and said proportional pressure difference valve means on the basis of the yaw rate deviation calculated by said yaw rate deviation calculation means, wherein said method includes;

a step of placing said normally open switching valve connected to one of said wheel brake cylinders in one hydraulic circuit of said dual hydraulic circuit, in the closed position, placing said normally open switching valve connected to the other one of said wheel brake cylinders in said one hydraulic circuit, in the open position, and controlling said pressure generating means, by said control means, on the basis of the yaw rate deviation calculated by said yaw rate deviation calculation means; and

a step of controlling said proportional pressure difference valve means, in the condition that said normally open switching valve connected to said one of said wheel brake cylinders in said one hydraulic circuit is placed in the closed position, placing said normally open switching valve connected to the other one of said wheel brake cylinders in said one hydraulic circuit in the open position, and controlling said pressure generating means.

2. A method for controlling a vehicle motion control apparatus as set forth in claim 1, wherein said proportional pressure difference valve means includes a proportional solenoid valve disposed between said master cylinder and said normally open switching valves in each hydraulic circuit, said proportional solenoid valve regulating the pressure difference between the hydraulic pressure at the side of said master cylinder and the hydraulic pressure at the side of said normally open switching valves to be of the desired value, and includes a relief valve disposed in parallel with said proportional solenoid valve for allowing the brake fluid to flow from said normally open switching valves toward said master cylinder when the hydraulic pressure at the side of said normally open switching valves exceeds a predetermined upper limit pressure.

3. A method for controlling a vehicle motion control apparatus as set forth in claim 1, wherein said proportional pressure difference valve means includes a proportional pressure difference valve disposed between said master cylinder and said normally open switching valves in each hydraulic circuit, and wherein said control means selects one of a communication position for said proportional pressure difference valve where flow of brake fluid is allowed through said proportional pressure difference valve, and a pressure difference position for said proportional pressure difference valve where flow of the brake fluid is restricted on the basis of the pressure difference between the hydraulic pressure at the side of said master cylinder and the hydraulic pressure at the side of said normally open switching valves to provide the pressure difference of the desired value.

4. A method for controlling a vehicle motion control apparatus as set forth in claim 1, wherein the vehicle motion control apparatus further comprises a reservoir for storing brake fluid drained from said pair of wheel brake cylinders, wherein said pressure generating means includes a hydraulic pressure pump for receiving therein the brake fluid from at least one of said reservoir and said master cylinder, and pressurizing the brake fluid in response to output from said control means, to discharge the hydraulic braking pressure.

5. A method for controlling a vehicle motion control apparatus as set forth in claim 1, wherein upon the operation of the brake pedal during operation of said automatic hydraulic pressure generating means, said control means maintains said normally open switching valve connected to said one of said wheel brake cylinders in said one hydraulic circuit in the closed position to hold the hydraulic braking pressure in said one of said wheel brake cylinders in said one hydraulic circuit, and maintains said normally open switching valve connected to said other one of said wheel brake cylinders in said one hydraulic circuit in the open position while controlling said valve means to supply the hydraulic braking pressure from both said master cylinder and said automatic hydraulic pressure generating means to said other one of said wheel brake cylinders in said one hydraulic circuit.

6. A method for controlling a vehicle motion control apparatus set forth In claim 1, wherein said proportional pressure difference valve means provides communication between said master cylinder and said normally open switching valves in each hydraulic circuit on the basis of the yaw rate deviation, and regulates a pressure difference between the hydraulic pressure at the side of said master cylinder and the hydraulic pressure at the side of said normally open switching valves to be of the desired value.