Vehicle motion control apparatus

• US 20050012390A1
• Filed: 07/16/2004
• Published: 01/20/2005
• Est. Priority Date: 07/17/2003
• Status: Active Grant

• Current Assignee: Advics Company Limited (Aisin Corp.)
• Original Assignee: Advics Company Limited (Aisin Corp.)
• Inventors: Yasui, Hideaki, Yogo, Kazutoshi, Kato, Toshihisa
• Granted Patent: US 7,658,454 B2
• Time in Patent Office: Days
• 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

The present invention is directed to a vehicle motion control apparatus, which includes normally open valves to supply hydraulic pressure discharged from a master cylinder into wheel brake cylinders, normally closed valves to reduce the wheel cylinder pressure, and a proportional pressure difference valve which is disposed between the master cylinder and the normally open valves, to regulate a pressure difference between the hydraulic pressure at the side of the master cylinder and the hydraulic pressure at the side of the normally open valves to be of a desired value. A pressure generating device is provided for generating the hydraulic pressure independently of the master cylinder to supply it into a passage between the pressure difference valve and the normally open valves. 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 the monitored vehicle state variable.

Claims

1. 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;

vehicle state monitor means for monitoring state variable of said vehicle; and

control means for controlling said pressure generating means on the basis of the state variable of said vehicle monitored by said vehicle state monitor means, said control means placing said normally open switching valve connected to one of said wheel brake cylinders in one hydraulic circuit of said dual hydraulic circuits, in the closed position, and 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 valve means on the basis of the state variable of said vehicle monitored by said vehicle state monitor means.

2. A vehicle motion control apparatus as set forth in claim 1, wherein said vehicle state monitor means includes yaw rate detection means for detecting an actual yaw rate of said vehicle, and wherein said control means includes desired yaw rate setting means for setting a desired yaw rate, and 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, said control means controlling said pressure generating means on the basis of the yaw rate deviation calculated by said yaw rate deviation calculation means, said control means placing said normally open switching valve connected to one of said wheel brake cylinders in one hydraulic circuit of said dual hydraulic circuits, in the closed position, and 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 valve means on the basis of the yaw rate deviation calculated by said yaw rate deviation calculation means.

3. 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.

4. 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.

5. A vehicle motion control apparatus as set forth in claim 1, further comprising 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.