Auxiliary energy brake system of automotive vehicles
AssigneeITT Automotive Europe GmbH
InventorAlfred Eckert
Life of this patent
Estimating the term…
Abstract
An auxiliary energy brake system of automotive vehicles has a central pressure source and a hydraulic system which includes pressure medium lines, electrically controllable hydraulic valves, and pressure medium orifices. A pressure sensor is located at the outlet of the pressure source. The braking pressure in the wheel brakes (P.sub.Rb) is established from the measured values (P.sub.meas), determined by the pressure sensor, and from the hydraulic conductance (D) of the orifices of the hydraulic system in accordance with formula P.sub.Rb f (D,P.sub.meas).
Claims22
A method for controlling brake pressure in a wheel brake of an automotive vehicle having a brake system including a pressure source and a hydraulic system for connecting said wheel brake with said pressure source, said method comprising the steps of:
- measuring pressure at the outlet of said pressure source to obtain pressure measurements representative of the pressure at the outlet of said pressure source;
- determining a hydraulic conductance between said pressure source and said wheel brake;
- determining, in response to said pressure measurements and to said hydraulic conductance, a value approximating brake pressure in said wheel brake;
- and
- generating valve control indications, in response to a nominal brake pressure and said value approximating brake pressure in said wheel brake, to control brake pressure in said wheel brake.
An auxiliary energy brake system for an automotive vehicle having wheel brakes, said system having a central pressure source;
- a hydraulic system which comprises:
- (a) pressure medium lines connecting the wheel brakes of the automotive vehicle with the pressure source, (b) electrically controllable hydraulic valves, and (c) at least one pressure medium orifice having a hydraulic conductance, D;
- and an electronic control unit for generating valve control signals and for controlling the braking pressure in the wheel brakes in dependence on measured pressure signals, P.sub.meas, measured by a pressure sensor arranged at the outlet of the pressure source, characterized in that the braking pressure, P.sub.Rb, in the wheel brakes is established as a function, f, of the measured pressure signals, and of the hydraulic conductance of the at least one orifice of the hydraulic system in accordance with the function
- P.sub.Rb =f(D, P.sub.meas) (1);
- and
- wherein the braking pressure P.sub.Rb (k) in the wheel brakes is recursively established in dependence on the hydraulic conductance and on the measured pressure signals, measured at the outlet of the pressure source, as a function of the pressure medium volume, v(k), in the wheel brake in accordance with function
- P.sub.Rb (k)=f(v(k)) (2).
- with
- v(k)=v(k-1)+T.sub.o -Q(k) (3),
- and ##EQU7##
- .DELTA.P=P.sub.meas (k)-P.sub.Rb (k-1), (5)
- with Q(k) being the volume flow in the hydraulic system, T.sub.o being the sampling time, and k being the respective sampling step.
An auxiliary energy brake system for an automotive vehicle comprising:
- a plurality of wheel brakes;
- a central pressure source having an outlet;
- a hydraulic system having:
- (a) a plurality of pressure medium lines connecting said wheel brakes with said pressure source,
- (b) a plurality of electrically controllable hydraulic valves arranged in said plurality of pressure medium lines, and
- (c) at least one pressure medium orifice having a hydraulic conductance, D;
- a pressure sensor at the outlet of said pressure source for measuring pressure at the outlet of said pressure source to obtain pressure measurements P.sub.meas representative of the pressure at the outlet of said pressure source;
- means, responsive to said pressure measurements measured by said pressure sensor and to said hydraulic conductance of said at least one pressure medium orifice of said hydraulic system, for determining a value approximating brake pressure in said plurality of wheel brakes;
- and
- an electronic control unit, responsive to a nominal brake pressure and said value approximating brake pressure in said plurality of wheel brakes, for generating valve control indications to control brake pressure in said plurality of wheel brakes.
Dependencies are inferred from the claim text.