Tracking diagnostic for continuously variable valve systems

Patent metadata

Field	Value
Publication number	US-10525982-B2
Application number	US-201715399228-A
Country	US
Kind code	B2
Filing date	Jan 5, 2017
Priority date	Jan 5, 2017
Publication date	Jan 7, 2020
Grant date	Jan 7, 2020

Abstract

A variable valve, method, and diagnostic system are provided that determine accuracy of a position of a variable valve. The variable valve, method, and diagnostic system are configured to determine a system error, the system error being the difference between a commanded position of the valve and a measured position of the valve provided through a feedback signal of the valve. The variable valve, method, and diagnostic system are further configured to determine that a diagnostic accuracy passing condition is met if: a) the system error is less than a predetermined positive error threshold and greater than a predetermined negative error threshold; b) a rate of change of the measured position exceeds a predetermined positive feedback rate threshold; or c) the rate of change of the measured position is less than a predetermined negative feedback rate threshold.

First claim

What is claimed is:

1. A method of determining accuracy of a position of a variable valve in an exhaust system of a motor vehicle, the method comprising:
determining a system error, the system error being a difference between a commanded position of the valve and a measured position of the valve provided through a feedback signal of the valve;
determining, via a controller, that a diagnostic accuracy passing condition is met if the system error is less than a predetermined positive error threshold and greater than a predetermined negative error threshold;
determining, via the controller, a rate of change of the measured position, if the system error is not less than the predetermined positive error threshold and greater than the predetermined negative error threshold;
determining, via the controller, that the diagnostic accuracy passing condition is met if the rate of change of the measured position exceeds a predetermined positive feedback rate threshold; and
determining, via the controller, that the diagnostic accuracy passing condition is met if the rate of change of the measured position is less than a predetermined negative feedback rate threshold.

2. The method of claim 1 , further comprising determining, via the controller, that a diagnostic accuracy failure condition is met if:
a) the system error is not less than the predetermined positive error threshold and the rate of change of the measured position does not exceed the predetermined positive feedback rate threshold; or
b) the system error is not greater than the predetermined negative error threshold and the rate of change of the measured position is not less than the predetermined negative feedback rate threshold.

3. The method of claim 2 , wherein the predetermined positive error threshold and the predetermined negative error threshold are equal in magnitude, and wherein the predetermined positive feedback rate threshold and the predetermined negative feedback rate threshold are equal in magnitude.

4. The method of claim 3 , further comprising providing the valve having an infinite number of possible positions between a fully open position and a fully closed position.

5. The method of claim 4 , further comprising determining, via the controller, whether enablement criteria are met prior to performing the steps of determining that the diagnostic accuracy passing condition is met and determining that the diagnostic accuracy failure condition is met.

6. The method of claim 5 , further comprising:
determining, via the controller, whether suspension criteria are met for suspending the diagnostic, the suspension criteria including at least one of: a new valve command signal after a steady-state period of the valve command signal and a new valve command signal changing the direction of the valve; and
if the suspension criteria are met, delaying at least one sampling interval prior to performing the steps of determining that the diagnostic accuracy passing condition is met and determining that the diagnostic accuracy failure condition is met.

7. The method of claim 6 , further comprising providing the valve as being electronically actuatable and having a Hall-Effect sensor configured to determine the measured position of the valve.

8. A diagnostic tracking system for tracking accuracy of a position of a variable valve in an exhaust system of a motor vehicle, the diagnostic tracking system comprising:
a system error module configured to determine a system error, the system error being the difference between a commanded position of the valve and a measured position of the valve provided through a feedback signal of the valve;
a rate of change module configured to determine a rate of change of the measured position;
a diagnostic accuracy passing module configured to determine that a diagnostic accuracy passing condition is met if at least one of
a) the system error is less than a predetermined positive error threshold and greater than a predetermined negative error threshold;
b) the rate of change of the measured position exceeds a predetermined positive feedback rate threshold; and
c) the rate of change of the measured position is less than a predetermined negative feedback rate threshold.

9. The diagnostic tracking system of claim 8 , further comprising a diagnostic accuracy failure module configured to determine that a diagnostic accuracy failure condition is met if:
a) the system error is not less than the predetermined positive error threshold and the rate of change of the measured position does not exceed the predetermined positive feedback rate threshold; or
b) the system error is not greater than the predetermined negative error threshold and the rate of change of the measured position is not less than the predetermined negative feedback rate threshold.

10. The diagnostic tracking system of claim 9 , wherein the predetermined positive error threshold and the predetermined negative error threshold are equal in magnitude, and wherein the predetermined positive feedback rate threshold and the predetermined negative feedback rate threshold are equal in magnitude.

11. The diagnostic tracking system of claim 10 , further comprising an enablement module configured to determine whether enablement criteria are met prior to activating the diagnostic accuracy passing module and the diagnostic accuracy failure module.

12. The diagnostic tracking system of claim 11 , further comprising a delay module configured to:
determine whether suspension criteria are met for suspending the diagnostic, the suspension criteria including at least one of: a new valve command signal after a steady-state period of the valve command signal and a new valve command signal changing the direction of the valve; and
if the suspension criteria are met, delay at least one sampling interval prior to activating the diagnostic accuracy passing module and the diagnostic accuracy failure module.

13. The diagnostic tracking system of claim 12 , wherein the valve has an infinite number of possible positions between a fully open and a fully closed position, the valve being electronically actuatable and having a Hall-Effect sensor configured to determine the measured position of the valve.

14. A variable valve system for a motor vehicle exhaust system, the variable valve system comprising:
a valve moveable between a fully open and a fully closed position, the valve being further moveable into an infinite number of possible positions between the fully open position and the fully closed position;
a valve actuator configured to move the valve into the fully open position, the fully closed position, and therebetween;
a sensor configured to sense a measured position of the valve;
a command input in communication with the valve actuator, the command input being configured to receive a command signal communicating a commanded position of the valve;
a feedback output in communication with the sensor, the feedback output configured to send a feedback signal communicating the measured position of the valve;
a control system configured to provide the command signal to the valve actuator through the command input and to receive the feedback signal through the feedback output, the control system comprising:
a system error module configured to determine a system error, the system error being the difference between the commanded position of the valve and the measured position of the valve;
a rate of change module configured to determine a rate of change of the measured position;
a diagnostic accuracy passing module configured to determine that a diagnostic accuracy passing condition is met if at least one of
a

Assignees

• Gm Global Tech Operations Llc

Inventors

• Suntharalingam Piranavan

Classifications

• F02D13/0242

  Variable control of the exhaust valves only · CPC title

• B60W2050/021

  Means for detecting failure or malfunction · CPC title

• F02D9/04

  concerning exhaust conduits (throttle valves, or arrangements thereof in conduits F02D9/08) · CPC title

• F02D41/221 Primary

  relating to the failure of actuators or electrically driven elements · CPC title

• Y02T10/40

  Engine management systems · CPC title