Method of calibrating offset of pressure sensor

Patent metadata

Field	Value
Publication number	US-2018292284-A1
Application number	US-201715784584-A
Country	US
Kind code	A1
Filing date	Oct 16, 2017
Priority date	Apr 11, 2017
Publication date	Oct 11, 2018
Grant date	—

Abstract

A method of calibrating an offset of a pressure sensor, by which an offset of a sensing value of a pressure sensor, which detects a pressure of hydrogen in a fuel cell system, is accurately calibrated. The method includes receiving, by a controller, a sensing value of a pressure sensor which detects a hydrogen pressure in a state where a hydrogen supply starts after a start of a fuel cell system; counting, by the controller, a time for which the sensing value of the pressure sensor increases from a first pressure P 1 to a second pressure P 2 ; calculating, by the controller, an offset value corresponding to the counted time by use of stored setting data; and calibrating, by the controller, a subsequent sensing value of the pressure sensor by the calculated offset value in real time when the offset value is calculated.

First claim

What is claimed is:

1 . A method of calibrating an offset of a pressure sensor, the method comprising:
step (a) of receiving, by a controller, a sensing value of a pressure sensor which detects a hydrogen pressure in a state where a hydrogen supply starts after a start of a fuel cell system, step (b) of counting, by the controller, a time for which the sensing value of the pressure sensor increases from a first pressure P 1 to a second pressure P 2 , step (c) of calculating, by the controller, an offset value corresponding to the counted time by use of stored setting data; and step (d) of calibrating, by the controller, a subsequent sensing value of the pressure sensor by the calculated offset value in real time when the offset value is calculated.

2 . The method of claim 1 , further comprising:
determining, by the controller, whether a calibration permissible condition is satisfactory based on information collected in the fuel cell system before the hydrogen supply starts after the start of the fuel cell system, wherein only when the calibration permissible condition is satisfactory, all the steps: receiving of the sensing value; counting of the time; calculating of the offset value; and calibrating the sensing value of the pressure sensor in real time are performed.

3 . The method of claim 1 , wherein the information includes the sensing value of the pressure sensor, and
the calibration permissible condition includes a condition where the sensing value of the pressure sensor is within an initial pressure range that is a range between an initial pressure lower limit value P i1 and an initial pressure upper limit value P i2 .

4 . The method of claim 3 , wherein the initial pressure lower limit value P i1 and the initial pressure upper limit value P i2 are set in the controller as pressure values equal to or lower than a value of atmospheric pressure.

5 . The method of claim 3 , wherein the information further includes a fuel cell stack voltage detected by a voltage detecting unit, and
the calibration permissible condition further includes a condition where the detected fuel cell stack voltage is less than a predetermined voltage.

6 . The method of claim 3 , wherein the information further includes at least one of an operation state of hydrogen purging performed by a hydrogen purge valve and a drain operation state of a water trap, and
the calibration permissible condition further includes at least one of a condition where hydrogen purging is in a non-operated state and a condition where a drain value of a water trap is in a closed state.

7 . The method of claim 1 , wherein the first pressure P 1 and the second pressure P 2 are set in the controller as pressure values larger than a value of atmospheric pressure.

8 . The method of claim 7 , wherein the first pressure P 1 and the second pressure P 2 are set in the controller as pressure values smaller than a value of a predetermined start target pressure.

9 . The method of claim 1 , wherein the setting data is a map in which an offset value is set as a value according to the time for which the sensing value of the pressure sensor increases from the first pressure P 1 to the second pressure P 2 , or an equation wherein the time is set as a variable and based on the variable an offset value is earned.

10 . The method of claim 1 , wherein a time of pressure while the sensing value of the pressure sensor in a normal state, without a generation of an offset, increases from the first pressure P 1 to the second pressure P 2 , is pre-stored in the controller,
In the setting data, an offset value is set as a positive value when the counted time in step (b) is shorter than the pre-stored time of increasing pressure i, wherein when the counted time counted in step (b) is longer than the pre-stored time of increasing pressure, the offset value is set as a negative value.

11 . The method of claim 10 , wherein the real-time calibrated sensing value of the pressure sensor in step (d) is calculated by Equation E1 below by using the offset value calculated based on the sensing value of the pressure sensor before the calibration and the setting data,
P calibration =P measure −P offset   (E1)
wherein, P measure is the sensing value of the pressure sensor before the calibration, P offset is an offset value calculated from the setting data, and P calibration is the real-time calibrated sensing value of the pressure sensor.

12 . The method of claim 1 , further comprising:
determining, by the controller, that the pressure sensor is broken down when an absolute value of the calculated offset value exceeds a predetermined value.

Assignees

• Hyundai Motor Co Ltd
• Kia Motors Corp

Inventors

• Kim Seon Hak
• Jeon Soon Il

Classifications

• H01M8/0438

  Pressure; Ambient pressure; Flow · CPC title

• G01L27/002 Primary

  Calibrating, i.e. establishing true relation between transducer output value and value to be measured, zeroing, linearising or span error determination · CPC title

• H01M8/04753

  of fuel cell reactants · CPC title

• H01M8/04388

  of anode reactants at the inlet or inside the fuel cell · CPC title

• H01M8/04302

  applied during start-up · CPC title