System and method for waste-gate valve diagnostics

Patent metadata

Field	Value
Publication number	US-10823092-B2
Application number	US-201916256774-A
Country	US
Kind code	B2
Filing date	Jan 24, 2019
Priority date	Jan 24, 2019
Publication date	Nov 3, 2020
Grant date	Nov 3, 2020

Abstract

Methods and systems are provided for diagnosing an exhaust waste-gate valve via an electric boost assist motor of an electric turbocharger. Degradation of the waste-gate valve is inferred based on the motor torque profile of the motor after commanding the waste-gate valve to an open or closed position on a torque transient. Deviation of the motor torque profile from the expected profile is used to infer if the valve is stuck open or closed, and actions are taken accordingly.

First claim

The invention claimed is:

1. A method for an engine coupled to a turbocharger, comprising:
during a torque transient,
commanding, with a signal output by a controller, a change in exhaust waste-gate valve position;
indicating, with the controller, degradation of the waste-gate valve based on a change in electrical energy input or output by an electric boost assist motor coupled to the turbocharger; and
setting, with the controller, a diagnostic code in response to indicating degradation of the waste-gate valve.

2. The method of claim 1 , further comprising monitoring, with the controller, the change in electrical energy input or output by the electric boost assist motor for a duration after commanding the change in waste-gate valve position.

3. The method of claim 2 , further comprising monitoring, with the controller, an actual boost pressure relative to a target boost pressure based on the torque transient.

4. The method of claim 2 , wherein the torque transient includes one of a pedal tip-in and a pedal tip-out.

5. The method of claim 2 , wherein when the torque transient is an increase in torque, the commanded change includes commanding the waste-gate valve closed, and when the torque transient is a decrease in torque, the commanded change includes commanding the waste-gate valve open.

6. The method of claim 5 , wherein the indicating includes:
indicating that the waste-gate valve is stuck open responsive to continued and/or increasing electrical energy output by the motor over the duration after commanding the waste-gate valve closed.

7. The method of claim 6 , wherein the indicating includes:
indicating that the waste-gate valve is stuck closed responsive to continued and/or increasing electrical energy input into the motor over the duration after commanding the waste-gate valve open.

8. The method of claim 7 , wherein the duration is a duration until a target boost pressure for the torque transient is reached.

9. The method of claim 7 , further comprising:
responsive to the indicating that the waste-gate valve is stuck open, increasing, with the controller, a gain value of a boost pressure feedback response of the electric boost assist motor and/or temporarily disabling boost usage.

10. A method for a turbocharged engine, comprising:
responsive to a pedal transient, commanding, with a signal output from a controller, a change in waste-gate valve position;
monitoring, with the controller, a torque profile of an electric boost assist motor coupled to a turbocharger following the commanding;
indicating, with the controller, degradation of the waste-gate valve based on the monitored torque profile relative to an expected torque profile; and
setting, with the controller, a diagnostic code in response to indicating degradation of the waste-gate valve.

11. The method of claim 10 , wherein when the pedal transient is a pedal tip-in, the commanded change includes commanding the waste-gate valve to a more closed position, and when the pedal transient is a pedal tip-out, the commanded change includes commanding the waste-gate valve to a more open position.

12. The method of claim 11 , wherein a target turbine speed is based on the pedal transient, and when the pedal transient is the pedal tip-in, the expected torque profile includes a transient increase in positive motor torque applied on a turbocharger shaft via the electric boost assist motor until a target turbine speed is reached, followed by intermittent bursts of negative motor torque applied on the turbocharger shaft via the electric boost assist motor to maintain the target turbine speed.

13. The method of claim 12 , wherein when the pedal transient is the pedal tip-out, the expected torque profile includes a transient increase in negative motor torque applied on the turbocharger shaft via the electric boost assist motor until the target turbine speed is reached, followed by intermittent bursts of positive motor torque applied on the turbocharger shaft via the electric boost assist motor to maintain the target turbine speed.

14. The method of claim 12 , wherein the indicating includes:
when the pedal transient is the pedal tip-in, indicating that the waste-gate valve is stuck open responsive to the monitored torque profile including a prolonged and gradual increase in the positive motor torque applied on the turbocharger shaft; and
when the pedal transient is the pedal tip-out, indicating that the waste-gate valve is stuck closed responsive to the monitored torque profile including a prolonged and gradual increase in the negative motor torque applied on the turbocharger shaft.

15. The method of claim 14 , further comprising:
responsive to the indicating that the waste-gate valve is stuck open, feedback operating, with the controller, the electric boost assist motor with a higher gain function and/or temporarily disabling boost usage.

16. The method of claim 10 , wherein monitoring the torque profile of an electric boost assist motor includes monitoring a change in state of charge of a battery coupled to the electric boost assist motor.

17. A boosted engine system, comprising:
an engine;
a turbocharger having an intake compressor coupled to an exhaust turbine via a shaft;
an electric motor/generator coupled to the shaft;
a battery coupled to the electric motor/generator;
a waste-gate passage including a waste-gate valve bypassing the exhaust turbine; and
a controller with computer-readable instructions stored on non-transitory memory that when executed cause the controller to:
command a change in position of the waste-gate valve via a signal output from the controller;
monitor a change in battery state of charge after commanding the change and until a target boost pressure is reached;
diagnose the waste-gate valve based on the monitored change in battery state of charge; and
set a diagnostic code based on the diagnosing.

18. The system of claim 17 , wherein the controller includes instructions to:
command the waste-gate valve to a more open position in response to a decrease in operator torque demand, a degree of opening of the waste-gate valve increased as the operator torque demand decreases from a current level; and
command the waste-gate valve to a more closed position in response to an increase in operator torque demand, a degree of closing of the waste-gate valve increased as the operator torque demand increases from the current level.

19. The system of claim 18 , wherein the controller includes instructions to:
indicate that the waste-gate valve is stuck closed when commanded to the more open position responsive to higher than expected rise in battery state of charge; and
responsive to the indication, disable boost usage.

20. The system of claim 18 , wherein the controller includes instructions to:
indicate that the waste-gate valve is stuck open when commanded to the more closed position responsive to higher than expected drop in battery state of charge; and
responsive to the indication, disable the boost usage.

Assignees

• Ford Global Tech Llc

Inventors

• Bastanipour Michael
• Herhusky Nicholas
• Stolzenfeld Timothy
• Xiao Baitao

Classifications

• Y02T10/40

  Engine management systems · CPC title

• Y02T10/12

  Improving ICE efficiencies · CPC title

• F02B37/18

  by bypassing exhaust {from the inlet to the outlet of turbine or to the atmosphere} · CPC title

• F02D2200/0604

  Estimation of fuel pressure · CPC title

• F02D41/0007 Primary

  for control of turbo-charged or super-charged engines (control of the pumps per se F02B37/12) · CPC title