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Method for diagnosing electric brake system

  • US 10,166,959 B2
  • Filed: 10/19/2016
  • Issued: 01/01/2019
  • Est. Priority Date: 10/19/2015
  • Status: Active Grant
First Claim
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1. A method for diagnosing an electric brake system, which includes a reservoir configured to store oil, a master cylinder at which first and second hydraulic ports are formed, connected to the reservoir, and having one or more pistons to discharge oil according to a pedal effort of a brake pedal, a first backup flow path configured to connect the first hydraulic port to a wheel cylinder, a second backup flow path configured to connect to the second hydraulic port to a wheel cylinder, a first cut valve provided at the first backup flow path and configured to control an oil flow, a second cut valve provided at the second backup flow path and configured to control an oil flow, a simulation device provided at a flow path branching from the first backup flow path, provided with a simulator valve provided at a flow path connecting a simulation chamber in which oil is accommodated to the reservoir, and configured to provide a reaction force according to the pedal effort of the brake pedal, a hydraulic pressure supply device configured to operate in response to an electrical signal output from a pedal displacement sensor sensing a displacement of the brake pedal and generate hydraulic pressure by means of an operation of a hydraulic piston, a first hydraulic flow path connected to the hydraulic pressure supply device and to the first backup flow path, a second hydraulic flow path connected to the hydraulic pressure supply device and to the second backup flow path, a hydraulic control unit connected to the first and second hydraulic flow paths, configured to deliver the hydraulic pressure discharged from the hydraulic pressure supply device to a wheel cylinder provided at each of wheels, and including first and second hydraulic circuits connected to different wheel cylinders, a first inlet valve, a second inlet valve, a third inlet valve, and a fourth inlet valves provided at an upstream side of the wheel cylinder to control hydraulic pressure flowing to the wheel cylinder installed at each of the wheels, first to fourth outlet valves configured to control opening and blocking of a flow path branching from a flow path between the first to fourth inlet valves and the wheel cylinder to be connected to the reservoir, and an electronic control unit configured to control the hydraulic pressure supply device and a plurality of valves on the basis of hydraulic pressure information and displacement information of the brake pedal, comprising a first diagnosis mode of:

  • closing the first cut valve and the second cut valve when the pedal effort is not provided to the brake pedal;

    operating the hydraulic pressure supply device to generate hydraulic pressure at the hydraulic control unit;

    measuring the hydraulic pressure in the first or second hydraulic circuit; and

    comparing the measured hydraulic pressure with a first reference pressure to diagnose abnormality of the first and second cut valves, the first to fourth inlet valves, and the first to fourth outlet valves,wherein the method further includes a second diagnosis mode of;

    opening the first cut valve and the second cut valve when the pedal effort is not provided to the brake pedal.

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