Diagnostic method for a compressor recirculation valve

Patent metadata

Field	Value
Publication number	US-2016160747-A1
Application number	US-201414565150-A
Country	US
Kind code	A1
Filing date	Dec 9, 2014
Priority date	Dec 9, 2014
Publication date	Jun 9, 2016
Grant date	—

Abstract

Methods are provided for identifying degradation in components of a compressor bypass valve (CBV). One method comprises commanding a periodic signal to the CBV and indicating degradation of a throttle of the CBV based on changes in pressure at an inlet of an intake throttle in response to the periodic signal.

First claim

1 . A method for a boosted engine, comprising:
commanding a periodic signal to a compressor bypass valve (CBV); and indicating degradation of a throttle of the CBV based on changes in pressure at an inlet of an intake throttle in response to the periodic signal.

2 . The method of claim 1 , wherein pressure at the inlet of the intake throttle is measured by a sensor coupled to an intake passage and located upstream of the intake throttle and downstream of an intake compressor of the boosted engine.

3 . The method of claim 2 , wherein the periodic signal is commanded by a controller of the boosted engine based on operator input.

4 . The method of claim 3 , wherein the periodic signal includes a square waveform.

5 . The method of claim 2 , wherein the periodic signal has a periodicity based on response time of a turbocharger of the boosted engine.

6 . The method of claim 5 , further comprising indicating degradation of the throttle of the CBV when changes in pressure at the inlet of the intake throttle do not substantially correspond to the periodicity of the periodic signal to the CBV.

7 . The method of claim 5 , further comprising indicating degradation of a position sensor of the CBV when changes in pressure at the inlet of the intake throttle substantially correspond to the periodicity of the periodic signal, and when a second commanded change in a position of the throttle of the CBV does not produce a corresponding change in a response of the position sensor.

8 . The method of claim 7 , wherein the second commanded change is not a periodic signal.

9 . The method of claim 7 , further comprising deactivating the CBV in response to the indicating of degradation of the position sensor of the CBV.

10 . The method of claim 9 , further comprising adjusting one or more of a wastegate, the intake throttle, and variable cam timing responsive to the deactivating of the CBV.

11 . The method of claim 1 , wherein the CBV is a continuously variable compressor bypass valve.

12 . A system, comprising:
an engine; a turbocharger for providing a boosted aircharge to the engine, the turbocharger including an exhaust turbine and an intake compressor; an intake throttle positioned in an intake passage downstream of the intake compressor; a wastegate coupled across the exhaust turbine; a continuously variable recirculation valve (CCRV) coupled across the intake compressor, the CCRV including a CCRV throttle and a CCRV position sensor; a throttle inlet pressure (TIP) sensor coupled to the intake passage upstream of the intake throttle and downstream of the intake compressor; and a control system with computer-readable instructions stored on non-transitory memory for:
commanding a periodic signal to the CCRV;
measuring changes in pressure at an inlet of the intake throttle via the TIP sensor; and
if the changes in pressure at the inlet of the intake throttle in response to the commanded periodic signal do not correspond to a frequency of the commanded periodic signal,
indicating degradation of the CCRV throttle.

13 . The system of claim 12 , wherein the control system includes further instructions for, if the changes in pressure at the inlet of the intake throttle in response to the commanded periodic signal substantially correspond to the frequency of the commanded periodic signal, not indicating degradation of the CCRV throttle.

14 . The system of claim 13 , wherein the control system includes additional instructions for indicating degradation of the CCRV position sensor based on a first determination of degradation of the CCRV, and the changes in pressure at the inlet of the intake throttle in response to the commanded periodic signal substantially corresponding to the frequency of the commanded periodic signal.

15 . The system of claim 14 , wherein the first determination of degradation of the CCRV includes a lack of change in an output of the CCRV position sensor responsive to a first commanded change in position of the CCRV, the first commanded change being distinct from the periodic signal.

16 . The system of claim 15 , wherein the periodic signal includes a square waveform with a period based on response time of the turbocharger.

17 . The system of claim 16 , wherein the control system includes further instructions for, deactivating the CCRV and adjusting one or more of the wastegate, a position of the intake throttle, and valve timing in response to deactivating the CCRV.

18 . A method for a boosted engine, comprising:
commanding a periodic signal command to a compressor recirculation valve (CRV) comprising a square waveform; and distinguishing between degradation of a position sensor of the CRV and a throttle of the CRV based on changes in pressure at an inlet of an intake throttle in response to the square waveform periodic signal command.

19 . The method of claim 18 , wherein the periodic signal command has a period slower than a response time of a turbocharger in the boosted engine, and wherein the throttle of the CRV is determined to be degraded when the changes in pressure at the inlet of intake throttle in response to the periodic signal command do not substantially correspond to a periodicity of the periodic signal.

20 . The method of claim 19 , wherein the position sensor of the CRV is determined to be degraded when changes in pressure at the inlet of the intake throttle substantially correspond to the periodicity of the periodic signal command to the CRV, and when a second commanded change in a position of the throttle of the CRV does not produce a corresponding change in a response of the position sensor, the second commanded change being distinct from the periodic signal command.

Assignees

• Ford Global Tech Llc

Inventors

• Ossareh Hamid-Reza
• Banker Adam Nathan
• Xiao Baitao

Classifications

• F02D41/20

  Output circuits, e.g. for controlling currents in command coils · CPC title

• F02D41/221

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

• G01L27/007

  Malfunction diagnosis, i.e. diagnosing a sensor defect · CPC title

• F02B37/16 Primary

  by bypassing charging air · CPC title

• F02D41/0007

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