Vehicle dynamics control system

Claim 2

A vehicle dynamics control system for an automotive vehicle with a diagonal split layout of brake circuits, said system comprising: a first brake line connected to a first diagonally-opposed pair of wheel-brake cylinders; a second brake line connected to a second diagonally-opposed pair of wheel-brake cylinders; a first brake-fluid pressure generator for generating a first brake-fluid pressure which is variable depending on a magnitude of brake-pedal depression; a second brake-fluid pressure generator for generating a second brake-fluid pressure, independently of said first brake-fluid pressure based on the magnitude of brake-pedal depression; a first brake-fluid pressure selector valve means for selecting a brake-fluid pressure to be fed to said first brake line from between said first and second brake-fluid pressures; a second brake-fluid pressure selector valve means for selecting a brake-fluid pressure to be fed to said second brake line from between said first and second brake-fluid pressures; a first pressure control valve means fluidly disposed in a first brake circuit including said first brake line for regulating a fluid pressure in each of said first diagonally-opposed pair of wheel-brake cylinders; a second pressure control valve means fluidly disposed in a second brake circuit including said second brake line for regulating a fluid pressure in each of said second diagonally-opposed pair of wheel-brake cylinders; a vehicle-behavior detector for detecting a vehicle's cornering behavior; and a brake-fluid pressure control means being responsive to input information from said vehicle-behavior detector for controlling said first and second brake-fluid pressure selector valve means and said first and second pressure control valve means; wherein said brake-fluid pressure control means operates to supply said second brake-fluid pressure to an inner front wheel-brake cylinder of said first and second diagonally-opposed pairs of wheel-brake cylinders for increasing a fluid pressure in the inner front wheel-brake cylinder and operates to reduce a fluid pressure in an outer rear wheel-brake cylinder of said first and second diagonally-opposed pairs of wheel-brake cylinders to a predetermined minimum brake-fluid pressure level when said input information from said vehicle-behavior detector indicates a vehicle understeer during a turn, and said brake-fluid pressure control means operates to supply said second brake-fluid pressure to an outer front wheel-brake cylinder of said first and second diagonally-opposed pairs of wheel-brake cylinders for increasing a fluid pressure in the outer front wheel-brake cylinder and operates to reduce a fluid pressure in an inner rear wheel-brake cylinder of said first and second diagonally-opposed pairs of wheel-brake cylinders to a predetermined minimum brake-fluid pressure level when said input information from said vehicle-behavior detector indicates a vehicle oversteer during a turn.

Claim 3

The vehicle dynamics control system as claimed in claim 1, wherein said brake-fluid pressure control means permits said first brake-fluid pressure to be fed to a brake line connected to both the outer front wheel-brake cylinder and the inner rear wheel-brake cylinder from between said first and second brake lines when said input information from said vehicle-behavior detector indicates the vehicle understeer during a turn, and permits said first brake-fluid pressure to be fed to a brake line connected to both the inner front wheel-brake cylinder and the outer rear wheel-brake cylinder from between said first and second brake lines when said input information from said vehicle-behavior detector indicates the vehicle oversteer during a turn.

Claim 4

The vehicle dynamics control system as claimed in claim 1, wherein said first brake-fluid pressure generator comprises a dual-brake system master cylinder with two pistons set in tandem.

Claim 5

The vehicle dynamics control system as claimed in claim 1, wherein said second brake-fluid pressure generator comprises a pair of single-directional type electric-motor driven hydraulic pumps being respectively disposed in said first and second brake circuits.

Claim 6

The vehicle dynamics control system as claimed in claim 1, wherein said vehicle-behavior detector comprises at least wheel speed sensors for monitoring front-left, front-right, rear-left and rear-right wheel speeds a yaw-velocity sensor for monitoring a yaw velocity about a z-axis of the vehicle, a lateral acceleration sensor for monitoring a lateral acceleration exerted on the vehicle, and a steering angle sensor for monitoring a steer angle.

Claim 7

A vehicle dynamics control system for an automotive vehicle with a diagonal split layout of brake circuits, said system comprising: a first brake line connected to a first diagonally-opposed pair of wheel-brake cylinders; a second brake line connected to a second diagonally-opposed pair of wheel-brake cylinders; a first brake-fluid pressure generator for generating a first brake-fluid pressure which is variable depending on a magnitude of brake-pedal depression; a second brake-fluid pressure generator for generating a second brake-fluid pressure, independently of said first brake-fluid pressure based on the magnitude of brake-pedal depression; a first group of brake-fluid pressure selector valves for selecting a brake-fluid pressure to be fed to said first brake line from between said first and second brake-fluid pressures; a second group of brake-fluid pressure selector valves for selecting a brake-fluid pressure to be fed to said second brake line from between said first and second brake-fluid pressures; a first group of pressure control valves fluidly disposed in a first brake circuit including said first brake line for regulating a fluid pressure in each of said first diagonally-opposed pair of wheel-brake cylinders; a second group of pressure control valves fluidly disposed in a second brake circuit including said second brake line for regulating a fluid pressure in each of said second diagonally-opposed pair of wheel-brake cylinders; a vehicle-behavior detector for detecting a vehicle's cornering behavior; and a control unit being configured to be connected to said vehicle-behavior detector for controlling said first and second groups of brake-fluid pressure selector valves and said first and second groups of pressure control valves, in response to input information from said vehicle-behavior detector; wherein said control unit operates to supply said second brake-fluid pressure to an inner front wheel-brake cylinder of said first and second diagonally-opposed pairs of wheel-brake cylinders for increasing a fluid pressure in the inner front wheel-brake cylinder and operates to reduce a fluid pressure in an outer rear wheel-brake cylinder of said first and second diagonally-opposed pairs of wheel-brake cylinders to a predetermined minimum brake-fluid pressure level when said input information from said vehicle-behavior detector indicates a vehicle understeer during a turn, and said control unit operates to supply said second brake-fluid pressure to an outer front wheel-brake cylinder of said first and second diagonally-opposed pairs of wheel-brake cylinders for increasing a fluid pressure in the outer front wheel-brake cylinder and operates to reduce a fluid pressure in an inner rear wheel-brake cylinder of said first and second diagonally-opposed pairs of wheel-brake cylinders to a predetermined minimum brake-fluid pressure level when said input information from said vehicle-behavior detector indicates a vehicle oversteer during a turn.

Claim 8

A vehicle dynamics control system for an automotive vehicle with a diagonal split layout of brake circuits, said system comprising: a first brake line connected to a first diagonally-opposed pair of wheel-brake cylinders; a second brake line connected to a second diagonally-opposed pair of wheel-brake cylinders; a first brake-fluid pressure generator for generating a first brake-fluid pressure which is variable depending on a magnitude of brake-pedal depression; a second brake-fluid pressure generator for generating a second brake-fluid pressure, independently of said first brake-fluid pressure based on the magnitude of brake-pedal depression; a first group of brake-fluid pressure selector valves for selecting a brake-fluid pressure to be fed to said first brake line from between said first and second brake-fluid pressures; a second group of brake-fluid pressure selector valves for selecting a brake-fluid pressure to be fed to said second brake line from between said first and second brake-fluid pressures; a first group of pressure control valves fluidly disposed in a first brake circuit including said first brake line for regulating a fluid pressure in each of said first diagonally-opposed pair of wheel-brake cylinders; a second group of pressure control valves fluidly disposed in a second brake circuit including said second brake line for regulating a fluid pressure in each of said second diagonally-opposed pair of wheel-brake cylinders; a vehicle-behavior detector for detecting a vehicle's cornering behavior; and a control unit being configured to be connected to said vehicle-behavior detector for controlling said first and second groups of brake-fluid pressure selector valves and said first and second groups of pressure control valves, in response to input information from said vehicle-behavior detector; wherein said control unit operates to supply said second brake-fluid pressure to an inner front wheel-brake cylinder of said first and second diagonally-opposed pairs of wheel-brake cylinders for increasing a fluid pressure in the inner front wheel-brake cylinder and operates to reduce a fluid pressure in an outer rear wheel-brake cylinder of said first and second diagonally-opposed pairs of wheel-brake cylinders to a predetermined minimum brake-fluid pressure level when said input information from said vehicle-behavior detector indicates a vehicle understeer during a turn, and said control unit operates to supply said second brake-fluid pressure to an outer front wheel-brake cylinder of said first and second diagonally-opposed pairs of wheel-brake cylinders for increasing a fluid pressure in the outer front wheel-brake cylinder and operates to reduce a fluid pressure in an inner rear wheel-brake cylinder of said first and second diagonally-opposed pairs of wheel-brake cylinders to a predetermined minimum brake-fluid pressure level when said input information from said vehicle-behavior detector indicates a vehicle oversteer during a turn.

Claim 9

The vehicle dynamics control system as claimed in claim 6, wherein said control unit permits said first brake-fluid pressure to be fed to a brake line connected to both the outer front wheel-brake cylinder and the inner rear wheel-brake cylinder from between said first and second brake lines when said input information from said vehicle-behavior detector indicates the vehicle understeer during a turn, and permits said first brake-fluid pressure to be fed to a brake line connected to both the inner front wheel-brake cylinder and the outer rear wheel-brake cylinder from between said first and second brake lines when said input information from said vehicle-behavior detector indicates the vehicle oversteer during a turn.

Claim 10

The vehicle dynamics control system as claimed in claim 6, wherein said first brake-fluid pressure generator comprises a dual-brake system master cylinder with two pistons set in tandem.

Claim 11

The vehicle dynamics control system as claimed in claim 6, wherein said second brake-fluid pressure generator comprises a pair of single-directional type electric-motor driven hydraulic pumps being respectively disposed in said first and second brake circuits.

Claim 12

The vehicle dynamics control system as claimed in claim 6, wherein said vehicle-behavior detector comprises at leastwheelspeedsensors for monitoring front-left, front-right, rear-left and rear-right wheel speeds a yaw-velocity sensor for monitoring a yaw velocity about a z-axis of the vehicle, a lateral acceleration sensor for monitoring a lateral acceleration exerted on the vehicle, and a steering angle sensor for monitoring a steer angle.