Identification of air and/or fuel metering drift

Patent metadata

Field	Value
Publication number	US-9670858-B2
Application number	US-85362110-A
Country	US
Kind code	B2
Filing date	Aug 10, 2010
Priority date	Sep 8, 2009
Publication date	Jun 6, 2017
Grant date	Jun 6, 2017

Abstract

The disclosure relates to a system and method for identifying whether a difference between measured lambda and computed lambda, based on mass air flow and mass fuel flow, is due to a drift in fuel metering or a drift in air metering. The determination is based on also measuring exhaust gas NOx using a NOx sensor. By comparing the measured NOx to modeled NOx, drift can be attributed appropriately to the air flow measurement and/or the fuel flow measurement. Appropriate correction in the calibration can be undertaken to overcome sensor drift and/or drift in the fuel injector/fuel system flow characteristics.

First claim

What is claimed:

1. A method comprising:
by a controller:
estimating a first NOx value based at least on a received sensor signal indicating measured mass air flow;
inferring fuel metering drift in a mass fuel flow measurement in response to a delta NOx value representing a difference between the first NOx value and a measured NOx value from an associated sensor being less than a first threshold and
controlling an engine in response to the fuel metering drift.

2. The method of claim 1 , further comprising:
correcting calibration coefficients associated with the mass fuel flow measurement in response to the inferring of fuel metering drift.

3. The method of claim 1 wherein estimating the first NOx value is further based on operating conditions of the engine.

4. The method of claim 1 wherein the delta NOx value is based on a difference between the first NOx value and the measured NOx value squared with the squared difference integrated over a predetermined period of time.

5. A method, comprising:
by an engine controller:
estimating NOx based on at least one measured parameter;
measuring NOx using at least one sensor of an engine;
determining a delta NOx based on the estimated NOx and the measured NOx;
detecting drift in air metering when the delta NOx is less than an associated threshold; and
controlling the engine responsive to the detected drift in air metering.

6. The method of claim 5 , further comprising:
by the controller:
estimating a second NOx value based at least on a second measured parameter when the delta NOx is greater than the threshold;
determining a second delta NOx based on a difference between the second NOx value and the measured NOx;
comparing the second delta NOx value to a second threshold;
detecting drift in fuel metering when the second delta NOx value is less than a second threshold; and
controlling the engine responsive to the detected drift in fuel metering.

7. The method of claim 5 wherein the at least one measured parameter comprises mass air flow.

8. A method, comprising:
estimating NOx using an engine controller having a NOx model based on values received by the controller from at least one sensor;
measuring NOx using a NOx sensor coupled to the engine controller;
determining a delta NOx between the estimated NOx and the measured NOx;
detecting drift in the at least one sensor when the delta NOx is less than an associated threshold; and
controlling an engine responsive to the detected drift.

9. The method of claim 8 wherein the at least one sensor comprises a mass airflow sensor.

10. The method of claim 8 wherein the at least one sensor comprises a fuel flow sensor.

Assignees

• Yacoub Yasser Mohamed Sayed
• Ford Global Tech Llc

Inventors

• Yacoub Yasser Mohamed Sayed

Classifications

• F02D41/1461

  of the exhaust gases emitted by the engine · CPC title

• F02D41/18

  by measuring intake air flow · CPC title

• F02D2200/0616

  determined by estimation · CPC title

• Y02T10/40

  Engine management systems · CPC title

• F02D41/1462

  with determination means using an estimation · CPC title