METHOD OF DIAGNOSING A SLOW EGR SYSTEM IN AN INTERNAL COMBUSTION ENGINE

• US 20110023845A1
• Filed: 07/31/2009
• Published: 02/03/2011
• Est. Priority Date: 07/31/2009
• Status: Active Grant

• Current Assignee: Detroit Diesel Corporation (Daimler Truck Holding AG)
• Original Assignee: Detroit Diesel Corporation (Daimler Truck Holding AG)
• Inventors: Menoyo-Alonso, Miguel, Allain, Marc C.
• Granted Patent: US 8,109,258 B2
• Time in Patent Office: Days
• US Class Current: 123/568.16
• CPC Class Codes: F02D 2041/1431 the system including an input-output delay
• CPC Class Codes: F02D 41/0072 Estimating, calculating or determining the EGR rate, amount or flow sensors in EGR systems F02M26/45
• CPC Class Codes: F02D 41/22 Safety or indicating devices for abnormal conditions in air/fuel ratio feedback systems F02D41/1495, in electric control linkage F02D11/107, in purge control systems F02M25/0809
• CPC Class Codes: F02M 26/05 High pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust system upstream of the turbine and reintroduced into the intake system downstream of the compressor
• CPC Class Codes: F02M 26/15 in relation to engine exhaust purifying apparatus
• CPC Class Codes: F02M 26/23 Layout, e.g. schematics
• CPC Class Codes: F02M 26/49 Detecting, diagnosing or indicating an abnormal function of the EGR system
• CPC Class Codes: G01M 15/10 by monitoring exhaust gases or combustion flame

Abstract

A method for diagnosing slow EGR response in an internal combustion engine equipped with an electronic controller with memory, comprising:

• • determining an actual EGR gradient;
  • determining an expected EGR gradient
  • comparing the expected EGR gradient to the actual EGR gradient
  • determining the expected EGR gradient is greater that the actual EGR gradient and logging a fault in the electronic controller if the expected EGR gradient is greater than the actual EGR gradient, and optionally activating a warning to alert the operator of the logging event.

Claims

1. A method for diagnosing slow EGR response in an internal combustion engine equipped with an electronic controller with memory, comprising:

determining an actual EGR gradient;

determining an expected EGR gradient

comparing the expected EGR gradient to the actual EGR gradient

determining the expected EGR gradient is greater that the actual EGR gradient and logging a fault in the electronic controller if the expected EGR gradient is greater than the actual EGR gradient by a predetermined amount.

2. The method of claim 1, wherein the engine continues normal operation if the expected EGR gradient is not greater than the actual EGR gradient.

3. The method of claim 1, wherein the slow EGR response is summarized as an amount of time it takes for the EGR to respond to at least a sudden change in EGR set point or a sudden change in change in engine operating condition, or both.

4. The method of claim 3, wherein the change in engine operating condition may include changes in engine speed, engine torque, and engine load.

5. The method of claim 1, wherein the expected EGR gradient is a difference based estimation of an EGR signal derivative.

6. The method of claim 1, wherein the expected EGR gradient is a function of the difference between the EGR set point and the actual EGR.

7. The method of claim 1, wherein said method is a continuous closed feedback loop.

8. The method of claim 1, further including activating a warning to alert an operator of the EGR condition.