Method and system of determining failure of urea level sensor

Patent metadata

Field	Value
Publication number	US-9322316-B2
Application number	US-201313862915-A
Country	US
Kind code	B2
Filing date	Apr 15, 2013
Priority date	Dec 28, 2012
Publication date	Apr 26, 2016
Grant date	Apr 26, 2016

Abstract

A method and a system of determining failure of a urea level sensor may include: determining whether a difference between current and previous urea levels is smaller than or equal to a first predetermined level; determining, if the difference between the current and previous urea levels is smaller than or equal to the first predetermined level, whether a vehicle speed is faster than a predetermined vehicle speed; determining, if vehicle speed is faster than the predetermined vehicle speed, whether a vehicle acceleration is higher than a predetermined acceleration; determining, if vehicle acceleration is higher than the predetermined acceleration, whether a difference between current and previous raw urea levels is smaller than a predetermined raw urea level; and storing stuck failure code and restricting an output or the vehicle speed if the difference between the current and previous raw urea levels is smaller than the predetermined raw urea level.

First claim

What is claimed is:

1. A method of determining failure of a urea level sensor, comprising:
determining whether a difference between a current urea level and a previous urea level is smaller than or equal to a first predetermined level;
determining, when the difference between the current urea level and the previous urea level is smaller than or equal to the first predetermined level, whether a vehicle speed is faster than a predetermined vehicle speed;
determining, when the vehicle speed is faster than the predetermined vehicle speed, whether a vehicle acceleration is higher than a predetermined acceleration;
determining, when the vehicle acceleration is higher than the predetermined acceleration, whether a difference between a current raw urea level and a previous raw urea level is smaller than a predetermined raw urea level; and
storing stuck failure code and restricting an output or the vehicle speed when the difference between the current raw urea level and the previous raw urea level is smaller than the predetermined raw urea level.

2. The method of claim 1 , further comprising storing the current urea level as a reference urea level when the difference between the current urea level and the previous urea level is larger than the first predetermined level.

3. The method of claim 2 , further comprising:
determining whether an accumulated urea consumption is larger than a predetermined consumption when the difference between the current raw urea level and the previous raw urea level is larger than or equal to the predetermined raw urea level;
determining whether a difference between the reference urea level and the current urea level is smaller than a second predetermined level when the accumulated urea consumption is larger than the predetermined consumption; and
storing drift failure code and restricting the output or the vehicle speed when the difference between the reference urea level and the current urea level is smaller than the second predetermined level.

4. A method of determining failure of a urea level sensor, comprising:
determining whether a difference between a current urea level and a previous urea level is smaller than or equal to a first predetermined level;
determining, when the difference between the current urea level and the previous urea level is smaller than or equal to the first predetermined level, whether a vehicle speed is faster than a predetermined vehicle speed;
determining, when the vehicle speed is faster than the predetermined vehicle speed, whether a vehicle acceleration is higher than a predetermined acceleration; and
determining, when the vehicle acceleration is higher than the predetermined acceleration, whether a difference between a current raw urea level and a previous raw urea level is smaller than a predetermined raw urea level,
wherein stuck failure code is stored when the difference between the current raw urea level and the previous raw urea level is smaller than the predetermined raw urea level in a state where the vehicle speed is faster than the predetermined vehicle speed and the vehicle acceleration is higher than the predetermined acceleration.

5. The method of claim 4 , wherein an output or the vehicle speed is restricted when the stuck failure code is stored.

6. The method of claim 4 , wherein drift failure code is stored when a difference between a reference urea level and the current urea level is smaller than a predetermined level in a state where the difference between the current raw urea level and the previous raw urea level is larger than or equal to the predetermined raw urea level and an accumulated urea consumption is larger than a predetermined consumption.

7. The method of claim 6 , wherein an output or the vehicle speed is restricted when the drift failure code is stored.

8. A system for determining failure of a urea level sensor which detects a raw urea level, comprising:
a vehicle speed sensor detecting a vehicle speed;
an acceleration sensor detecting a vehicle acceleration or calculating the vehicle acceleration from the detected vehicle speed;
a urea pressure sensor detecting a urea pressure of a dosing module; and
a control unit electrically connected to the urea level sensor, the vehicle speed sensor, the acceleration sensor and the urea pressure sensor, calculating a urea level from the raw urea level, determining the failure of the urea level sensor, and performing control according to the failure determination;
wherein the control unit determines whether a difference between a current urea level and a previous urea level is smaller than or equal to a first predetermined level;
wherein the control unit determines, when the difference between the current urea level and the previous urea level is smaller than or equal to the first predetermined level, whether the vehicle speed is faster than a predetermined vehicle speed;
wherein the control unit determines, when the vehicle speed is faster than the predetermined vehicle speed, whether the vehicle acceleration is higher than a predetermined acceleration;
wherein the control unit determines, when the vehicle acceleration is higher than the predetermined acceleration, whether a difference between a current raw urea level and a previous raw urea level is smaller than a predetermined raw urea level; and
wherein the control unit stores stuck failure code when the difference between the current raw urea level and the previous raw urea level is smaller than the predetermined raw urea level in a state where the vehicle speed is faster than the predetermined vehicle speed and the vehicle acceleration is higher than the predetermined acceleration.

9. The system of claim 8 , wherein the control unit restricts an output or the vehicle speed when the stuck failure code is stored.

10. The system of claim 8 , wherein the control unit stores drift failure code when a difference between a reference urea level and the current urea level is smaller than a predetermined level in a state where the difference between the current raw urea level and the previous raw urea level is larger than or equal to the predetermined raw urea level and an accumulated urea consumption is larger than a predetermined consumption.

11. The system of claim 10 , wherein the control unit restricts an output or the vehicle speed when the drift failure code is stored.

Assignees

• Hyundai Motor Co Ltd
• Kia Motors Corp

Inventors

• Jung Jae-Yoon

Classifications

• Y02T10/24

  Cross-Sectional Technologies · mapped topic

• F01N2610/14

  Arrangements for the supply of substances, e.g. conduits · CPC title

• F01N2610/148

  Arrangement of sensors · CPC title

• F01N3/2066

  Selective catalytic reduction [SCR] · CPC title

• F01N2900/1814

  Tank level · CPC title