Fuel vapor system diagnostic systems and methods

• US 10,197,017 B2
• Filed: 08/30/2016
• Issued: 02/05/2019
• Est. Priority Date: 12/01/2015
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Casetti, Martino, Burleigh, Darrell W., Church, Bruce A.
• Primary Examiner(s): Huynh, Hai H
• Assistant Examiner(s): Laguarda, Gonzalo
• Application Number:
  US15/251,709
• Publication Number:
  US 20170152813A1
• Time in Patent Office: 889 Days
• Field of Search: 123520, 123497, 701107, 7311439
• CPC Class Codes: B01D 2257/7022 Aliphatic hydrocarbons
• CPC Class Codes: B01D 2259/4516 for fuel vapour recovery systems
• CPC Class Codes: B01D 53/0407 Constructional details of adsorbing systems
• CPC Class Codes: F02D 2041/1409 using at least a proportional, integral or derivative controller
• CPC Class Codes: F02D 2041/141 using a feed-forward control element
• CPC Class Codes: F02D 2041/223 Diagnosis of fuel pressure sensors
• CPC Class Codes: F02D 41/0032 Controlling the purging of the canister as a function of the engine operating conditions
• CPC Class Codes: F02D 41/1401 characterised by the control or regulation method F02D41/1473, F02D41/1477 take precedence
• CPC Class Codes: F02D 41/222 relating to the failure of sensors or parameter detection devices
• CPC Class Codes: F02M 25/0809 Judging failure of purge control system
• CPC Class Codes: G07C 5/006 Indicating maintenance
• CPC Class Codes: G07C 5/0808 Diagnosing performance data testing of vehicles G01M17/00; testing of electrical installation on vehicles G01R31/005
• CPC Class Codes: G07C 5/0825 using optical means
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A fuel vapor system for a vehicle includes a fuel vapor canister that traps fuel vapor from a fuel tank of the vehicle. A purge valve opens to allow fuel vapor flow to an intake system of an engine and closes to prevent fuel vapor flow to the intake system of the engine. An electrical pump pumps fuel vapor from the fuel vapor canister to the purge valve. A diagnostic module (a) selectively diagnoses a fault in the fuel vapor system based on at least one of: (i) a speed of the electrical pump measured using a pump speed sensor; and (ii) a pressure at a location between the electrical pump and the purge valve, and (b) illuminates a malfunction indicator lamp (MIL) within a passenger cabin of the vehicle when the fault is diagnosed.

Claims

1. A fuel vapor system for a vehicle, comprising:

a fuel vapor canister that traps fuel vapor from a fuel tank of the vehicle;

a purge valve that opens to allow fuel vapor flow to an intake system of an engine and that closes to prevent fuel vapor flow to the intake system of the engine;

an electrical pump that pumps fuel vapor from the fuel vapor canister to the purge valve; and

a diagnostic module that (a) selectively diagnoses a fault in the fuel vapor system based on a pressure at a location between the electrical pump and the purge valve, and that (b) illuminates a malfunction indicator lamp (MIL) within a passenger cabin of the vehicle when the fault is diagnosed,

wherein the diagnostic module;

selectively closes the purge valve when the electrical pump is on; and

diagnoses the fault based on an average of values of the pressure at the location between the electrical pump and the purge valve taken after the closing of the purge valve.

2. The fuel vapor system of claim 1 wherein the diagnostic module selectively diagnoses the fault further based on a speed of the electrical pump measured using a pump speed sensor, and wherein the diagnostic module diagnoses the fault when the speed of the electrical pump measured using the pump speed sensor is greater than a predetermined maximum speed measurable by the pump speed sensor.

3. The fuel vapor system of claim 1 wherein the diagnostic module selectively diagnoses the fault further based on a speed of the electrical pump measured using a pump speed sensor, and wherein the diagnostic module diagnoses the fault when the speed of the electrical pump measured using the pump speed sensor is less than a predetermined minimum speed measurable by the pump speed sensor.

4. The fuel vapor system of claim 1 wherein the diagnostic module selectively diagnoses the fault further based on a speed of the electrical pump measured using a pump speed sensor, and wherein the diagnostic module diagnoses the fault when a difference between the speed of the electrical pump measured using the pump speed sensor and a target speed of the electrical pump is one of:

greater than a first predetermined speed that is greater than zero; and

less than a second predetermined speed that is less than zero.

5. The fuel vapor system of claim 1 wherein the diagnostic module closes the purge valve in response to a determination that a speed of the electrical pump measured using a pump speed sensor is greater than a predetermined speed.

6. The fuel vapor system of claim 1 wherein the diagnostic module diagnoses the fault when the average of the values of the pressure at the location between the electrical pump and the purge valve taken after the closing of the purge valve is less than a predetermined pressure.

7. The fuel vapor system of claim 1 wherein the diagnostic module further:

selectively opens the purge valve after the closing of the purge valve; and

diagnoses the fault when the pressure at the location between the electrical pump and the purge valve is not less than a predetermined pressure within a predetermined period after the opening of the purge valve.

8. The fuel vapor system of claim 7 wherein the diagnostic module opens the purge valve after the closing of the purge valve when the average is greater than a second predetermined pressure that is greater than the predetermined pressure.

9. The fuel vapor system of claim 1 wherein the diagnostic module:

determines a measured value based on a barometric pressure and the pressure at the location between the electrical pump and the purge valve;

determines an expected value based on the barometric pressure and a target pressure at the location between the electrical pump and the purge valve; and

selectively diagnoses the fault based on the measured value and the expected value.

10. A method for a vehicle, comprising:

pumping, using an electrical pump, fuel vapor from a fuel vapor canister to a purge valve, the fuel vapor canister trapping fuel vapor from a fuel tank of the vehicle;

selectively opening the purge valve to allow fuel vapor flow to an intake system of an engine;

selectively closing the purge valve to prevent fuel vapor flow to the intake system of the engine;

selectively diagnosing a fault in a fuel vapor system based on a pressure at a location between the electrical pump and the purge valve;

selectively closing the purge valve when the electrical pump is on;

diagnosing the fault based on an average of values of the pressure at the location between the electrical pump and the purge valve taken after the closing of the purge valve; and

illuminating a malfunction indicator lamp (MIL) within a passenger cabin of the vehicle when the fault is diagnosed.

11. The method of claim 10 further comprising:

selectively diagnosing the fault in a fuel vapor system further based on a speed of the electrical pump measured using a pump speed sensor; and

diagnosing the fault when the speed of the electrical pump measured using the pump speed sensor is greater than a predetermined maximum speed measurable by the pump speed sensor.

12. The method of claim 10 further comprising:

selectively diagnosing the fault in a fuel vapor system further based on a speed of the electrical pump measured using a pump speed sensor; and

diagnosing the fault when the speed of the electrical pump measured using the pump speed sensor is less than a predetermined minimum speed measurable by the pump speed sensor.

13. The method of claim 10 further comprising:

selectively diagnosing the fault in a fuel vapor system further based on a speed of the electrical pump measured using a pump speed sensor; and

diagnosing the fault when a difference between the speed of the electrical pump measured using the pump speed sensor and a target speed of the electrical pump is one of;

greater than a first predetermined speed that is greater than zero; and

less than a second predetermined speed that is less than zero.

14. The method of claim 10 wherein selectively closing the purge valve includes closing the purge valve in response to a determination that a speed of the electrical pump measured using a pump speed sensor is greater than a predetermined speed.

15. The method of claim 10 further comprising diagnosing the fault when the average of the values of the pressure at the location between the electrical pump and the purge valve taken after the closing of the purge valve is less than a predetermined pressure.

16. The method of claim 10 further comprising:

selectively opening the purge valve after the closing of the purge valve; and

diagnosing the fault when the pressure at the location between the electrical pump and the purge valve is not less than a predetermined pressure within a predetermined period after the opening of the purge valve.

17. The method of claim 16 wherein selectively opening the purge valve includes opening the purge valve after the closing of the purge valve when the average is greater than a second predetermined pressure that is greater than the predetermined pressure.

18. The method of claim 10 further comprising:

determining a measured value based on a barometric pressure and the pressure at the location between the electrical pump and the purge valve;

determining an expected value based on the barometric pressure and a target pressure at the location between the electrical pump and the purge valve; and

selectively diagnosing the fault based on the measured value and the expected value.