Title of Invention

METHOD TO DETECT A CONTAMINATED FUEL INJECTOR

Abstract A method of diagnosing a fuel injector of an engine system as contaminated is provided. The method comprises: recording a first fuel injection quantity; commanding a fuel rail pressure high; recording a second fuel injection quantity while the fuel rail pressure is high; and diagnosing the fuel injector as contaminated if the first fuel injection quantity is greater than the second fuel injection quantity.
Full Text GP-306882-PTE-CD
1
METHOD TO DETECT A CONTAMINATED FUEL INJECTOR
FIELD OF THE INVENTION
[0001] The present invention relates to methods and systems for
diagnosing contaminated fuel injectors.
BACKGROUND OF THE INVENTION
[0002] Fuel and air injection quantities supplied to an engine are
controlled to meet fuel economy requirements and emission standards.
Closed loop control systems sense oxygen levels in exhaust flowing from
the engine in order to control air and fuel quantities flowing into the
engine. If engine components such as fuel injectors malfunction, fuel and
air injection quantities may not be accurate. Inaccuracies in injection
quantities may increase emissions and/or decrease fuel economy.
[0003] If a fuel injector malfunctions, it is commonly due to
contaminates in the fuel injector. Sediment within the fuel or fuel tank may
contaminate a fuel injector. Contaminated fuel injectors can increase
emissions, smoke, and/or engine noise. Conventional methods of
diagnosing a contaminated fuel injector require removal of the fuel injector
from the engine in order to test the fuel injector on a flow bench.
Disassembly of an engine can be both time consuming and costly.
Furthermore, an operator of the vehicle receives no indication of the
malfunction until the vehicle has been brought to a service station.

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SUMMARY OF THE INVENTION
[0004] Accordingly, a method of diagnosing a fuel injector of an
engine system as contaminated is provided. The method comprises:
recording a first fuel injection quantity; commanding a fuel rail pressure
high; recording a second fuel injection quantity while the fuel rail pressure
is high; and diagnosing the fuel injector as contaminated if the first fuel
injection quantity is greater than the second fuel injection quantity.
[0005] In other features, the method comprises adjusting
airflow and commanding the adjusted airflow if the fuel injector is
diagnosed as contaminated.
[0006] In still other features, the method comprises sending
a notification signal if the fuel injector is diagnosed as contaminated.
[0007] Further areas of applicability of the present invention will
become apparent from the detailed description provided hereinafter. It
should be understood that the detailed description and specific examples,
while indicating the preferred embodiment of the invention, are intended
for purposes of illustration only and are not intended to limit the scope of
the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The present invention will become more fully understood
from the detailed description and the accompanying drawings, wherein:

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[0009] Figure 1 is a functional block diagram of a diesel fuel
injection system;
[0010] Figure 2 is a diagram illustrating a contaminated fuel
injector;
[0011] Figures 3A and 3B are graphs illustrating the
characteristics of injection quantity;
[0012] Figure 4 is a graph illustrating an indicated fuel injection
quantity when rail pressure is adjusted; and
[0013] Figure 5 is a flowchart illustrating an embodiment of the
method for diagnosing a contaminated fuel injector.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0014] The following description of the preferred embodiment(s)
is merely exemplary in nature and is in no way intended to limit the
invention, its application, or uses. For purposes of clarity, the same
reference numbers will be used in the drawings to identify similar
elements. As used herein, the term module refers to an application
specific integrated circuit (ASIC), an electronic circuit, a processor
(shared, dedicated, or group) and memory that executes one or more
software or firmware programs, a combinational logic circuit, and/or other
suitable components that provide the described functionality.
[0015] Referring now to Figure 1, an engine system 10 includes
an engine 12 that combusts an air and fuel mixture to produce drive
torque. Air is drawn into an intake manifold 14 through a compressor 16.
Air within the intake manifold 14 is distributed into cylinders 18. Although

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four cylinders 18 are illustrated, it can be appreciated that the engine
system can be implemented in diesel engines having a plurality of
cylinders including, but not limited to, 2, 3, 5, 6, 8, 10, 12 and 16 cylinders.
[0016] Air is drawn into the cylinder 18 through an intake port. A
fuel rail 20 supplies fuel to fuel injectors 22. The fuel injector 22 directly
injects fuel into the cylinder 18. An intake valve 24 selectively opens and
closes to enable air to enter the cylinder 18. A piston (not shown)
compresses the air/fuel mixture within the cylinder 18. Heat from the
compressed mixture ignites the fuel. Forces from the combustion drive
the piston. The piston drives a crankshaft (not shown) to produce drive
torque.
[0017] Combustion exhaust within the cylinder 18 is forced out
through an exhaust manifold 26 when an exhaust valve 28 is in an open
position. Exhaust is treated in an exhaust system (not shown). Although
single intake and exhaust valves 24,28 are illustrated, it can be
appreciated that the engine 12 can include multiple intake and exhaust
valves 24,28 per cylinder 18.
[0018] A control module 30 determines and controls an air and
fuel injection quantity to be supplied to each cylinder 18 based on engine
operating conditions. The control module 30 diagnoses contaminated fuel
injectors 22 and reports the diagnosis to an operator of the system 10.
Based on the diagnosis, the control module 30 adjusts a quantity of air
delivered to the cylinder 18 with the contaminated injector 22 via the
intake valve 24.

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[0019] Referring now to Figure 2, a fuel injector is shown in
more detail. When contaminated fuel is supplied to the engine 12, a
chemical reaction can occur which creates fuel deposits. Deposits stick to
sensitive movement areas shown at 32-42. The fuel deposits of the
sensitive movement areas 32-42 increase friction thus leading to an
uncontrolled injection quantity. Figures 3A and 3B illustrate the effects on
fuel quantities for a contaminated injector. The uncontrolled fuel injection
quantity will increase a pilot injection quantity (PIQ). The increase in PIQ
will result in a reduction of indicated main injection (IF) quantity. A
reduction in the indicated injection (IF) quantity will lead to a reduction of
indicated air flow. Actual total injection quantity (Q) will not change but
actual airflow will reduce.
[0020] The control module 30 can diagnose a contaminated fuel
injector 22 by monitoring the indicated fuel quantity when pressure to the
fuel rail 20 is adjusted. Figure 4 illustrates an IF quantity when rail
pressure is adjusted. Indicated fuel injection quantity is represented along
the y-axis at 50. Rail pressure is indicated along the x-axis at 52. An
indicated fuel quantity for a non-contaminated fuel injector is shown at 54.
An indicated fuel quantity for a contaminated fuel injector is shown at 56.
Line A represents a point where fuel rail pressure is normal for engine
operation. Line B represents a point where fuel rail pressure is increased
for diagnosis purposes. When rail pressure is increased and indicated
fuel injection quantity drops below normal, the fuel injector can be
diagnosed as contaminated.

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[0021] Figure 5 illustrates an embodiment of the method for
diagnosing a contaminated injector. In order to diagnose an injector, the
engine system must be warmed up and load from electrical devices (e.g.
air conditioner, defogger, seat heater, audio system, head lamps) must not
be present. Control records an indicated fuel quantity at normal fuel rail
pressure at 100. Control adjusts fuel rail pressure higher at 110 and
records the new indicated fuel quantity at 120. If the indicated fuel
quantity at normal rail pressure is less than or equal to the indicated fuel
quantity at higher rail pressure at 130, control loops back and records an
indicated fuel quantity at 100.
[0022] Otherwise, if the indicated fuel quantity at normal rail
pressure is greater than the indicated fuel quantity at the higher rail
pressure at 130, target airflow is adjusted at 140. Control then adjusts fuel
rail pressure to normal at 150 and records an indicated fuel quantity at the
normal rail pressure at 160. Control adjusts fuel rail pressure higher at
170 and records the new indicated fuel quantity at 180. If the indicated
fuel quantity at normal rail pressure is greater than the indicated fuel
quantity at higher rail pressure at 190, control notifies the operator at 200.
Otherwise control loops back to step 100.
[0023] The method illustrated in Figure 5 requires two
consecutive incidences of diagnosing the contamination before notifying
an operator. As can be appreciated, other known methods for
implementing diagnostic notification requirements can be incorporated into
the method. For example, an X number of diagnosis must be true within Y

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number of samples before notification. Alternatively, an X number of
diagnosis must be true within a drive cycle of a vehicle before notification.
[0024] As can be appreciated, the notification can be made by
sending a signal to illuminate an indicator light of a vehicle containing the
system 10, sounding a chime, or any other known means of notifying an
operator. Either in addition to or alternative to notifying the operator,
control can set a diagnostic code and send a wireless communication
signal including the code notifying an operator located remotely from the
system.
[0025] Referring back to Figure 5, in another embodiment the
method of diagnosing a contaminated fuel injector can be performed by a
technician via a service tool i.e. Tech2. The technician can manipulate the
service tool to request the control module to adjust rail pressure higher
and report an indicated fuel quantity. If the indicated fuel quantity drops
below normal, this is an indication to the service technician that the
injector is contaminated and needs replacement.
[0026] Those skilled in the art can now appreciate from the
foregoing description that the broad teachings of the present invention can
be implemented in a variety of forms. Therefore, while this invention has
been described in connection with particular examples thereof, the true
scope of the invention should not be so limited since other modifications
will become apparent to the skilled practitioner upon a study of the
drawings, specification, and the following claims.

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CLAIMS
What is claimed is:
1. A method of diagnosing a fuel injector of an engine system
as contaminated, comprising:
recording a first fuel injection quantity;
commanding a fuel rail pressure high;
recording a second fuel injection quantity while the fuel rail
pressure is high; and
diagnosing the fuel injector as contaminated if the first fuel
injection quantity is greater than the second fuel injection quantity.
2. The method of claim 1 further comprising adjusting airflow
and commanding the adjusted airflow if the fuel injector is diagnosed as
contaminated.
3. The method of claim 1 further comprising:
consecutively repeating the method of claim 1 a selectable
number of times; and
setting a diagnostic code to true if each time of the
selectable number of times the fuel injector is diagnosed as contaminated.
4. The method of claim 1 further comprising sending a
notification signal if the fuel injector is diagnosed as contaminated.

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5. The method of claim 4 wherein said sending a notification
signal comprises sending a signal to illuminate an indicator light of a
vehicle.
6. The method of claim 4 wherein said sending a notification
signal comprises sending a signal to sound a notification chime of a
vehicle.
7. The method of claim 4 further comprising:
setting a diagnostic code to true when the fuel injector is
contaminated; and
wherein said sending a notification signal comprises sending
a wireless communication signal indicating the diagnostic code to a
remote operator.
8. The method of claim 1 further comprising repeating the
method of claim 1 for a selectable number of samples and wherein if said
fuel injector is diagnosed as contaminated for a selected number of
incidences within said selected number of samples, a diagnostic code is
set to true.
9. The method of claim 1 wherein said method is performed by
a controller while a vehicle is operating and after the engine system is
warm.

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10. The method of claim 9 wherein said method is performed if
no electrical load exists.
11. The method of claim 1 wherein said method is performed by
a technician via a service tool.
12. A system for diagnosing a contaminated fuel injector of an
engine system, comprising:
a first storage device that stores a first recorded injection
quantity when pressure of fuel in a fuel rail is normal;
a second storage device that stores a second recorded
injection quantity when pressure of fuel in said fuel rail is high; and
a processor that commands pressure to the fuel rail and
diagnoses the fuel injector as contaminated if said first recorded injection
quantity is greater than said second recorded injection quantity.
13. The system of claim 12 wherein said processor sets a
diagnostic code to true if the fuel injector is diagnosed as contaminated.
14. The system of claim 12 wherein said processor compares
said first recorded injection quantity and said second recorded injection
quantity a selectable number of samples, and if said first recorded
injection quantity is greater than said second recorded injection quantity a
selectable number of incidences within said selectable number of
samples, a diagnostic code is set to true.

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15. The system of claim 12 wherein said processor compares
said first recorded injection quantity and said second recorded injection
quantity a selectable number of times, and if said first recorded injection
quantity is greater than said second recorded injection quantity each time
of said selectable number of times, a diagnostic code is set to true.
16. The system of claim 13 wherein said processor sends a
notification message indicating that the fuel injector is contaminated.
17. The method of claim 16 wherein said processor sends a
notification message to illuminate an indicator light of a vehicle.
18. The method of claim 16 wherein said processor sends a
notification message to sound a chime in a vehicle.
19. The method of claim 16 wherein said processor sends a
wireless communication signal to a remote operator.
20. The method of claim 12 wherein said processor and said first
and second storage devices are contained within a service tool.
21. The method of claim 12 wherein said processor and said first
and said second storage devices are contained within a controller.

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22. The method of claim 12 wherein said processor diagnoses
the fuel injector if the engine system is warm.
23. The method of claim 21 wherein said processor diagnoses
the fuel injector if load from electrical loads is not present.
Dated this 3rd day of SEPTEMBER 2007


A method of diagnosing a fuel injector of an engine system as
contaminated is provided. The method comprises: recording a first fuel
injection quantity; commanding a fuel rail pressure high; recording a
second fuel injection quantity while the fuel rail pressure is high; and
diagnosing the fuel injector as contaminated if the first fuel injection
quantity is greater than the second fuel injection quantity.

Documents:

01239-kol-2007-abstract.pdf

01239-kol-2007-assignment.pdf

01239-kol-2007-claims.pdf

01239-kol-2007-correspondence others 1.1.pdf

01239-kol-2007-correspondence others 1.2.pdf

01239-kol-2007-correspondence others.pdf

01239-kol-2007-description complete.pdf

01239-kol-2007-drawings.pdf

01239-kol-2007-form 1.pdf

01239-kol-2007-form 2.pdf

01239-kol-2007-form 3.pdf

01239-kol-2007-form 5.pdf

01239-kol-2007-priority document.pdf

1239-KOL-2007-(01-09-2011)-ASSIGNMENT.pdf

1239-KOL-2007-(01-09-2011)-FORM 16.pdf

1239-KOL-2007-(01-09-2011)-PA.pdf

1239-KOL-2007-CORRESPONDENCE OTHERS 1.1.pdf

1239-KOL-2007-CORRESPONDENCE OTHERS 1.3.pdf

1239-KOL-2007-FORM 18.pdf

1239-KOL-2007-FORM 26.pdf

1239-KOL-2007-FORM 27.pdf

abstract-01239-kol-2007.jpg


Patent Number 237918
Indian Patent Application Number 1239/KOL/2007
PG Journal Number 03/2010
Publication Date 15-Jan-2010
Grant Date 12-Jan-2010
Date of Filing 03-Sep-2007
Name of Patentee GM GLOBAL TECHNOLOGY OPERATIONS, INC.
Applicant Address 300 GM RENAISSANCE CENTER, DETROIT, MICHIGAN
Inventors:
# Inventor's Name Inventor's Address
1 THOMAS WAGNER LUCY WEINERT-STR.6 TREBUR 65468
2 TOSHIO ICHIMASA 1-28-48 KURIHARA-CHUUOU, ZAMA-SHI, KANAGAWA-KEN 228-014
3 YOSHIKI TORII 3-17-1-409 HIGASHI-RINNKANN SAGAMIHARA-SHI, KANAGAWA-KEN 228-0811
4 NILS SANDMANN SAUSENHEIMER STRASSE 17 GRUENSTADT, 67269
5 DOUGLAS E. TROMBLEY SACHSENRING 21, EPPSTEIN-BREMTHAL 65817
6 JEFFREY J. ALLEN 2565 NORWOOD ROAD, BLOOMFIELD HILLS, MI 48302
7 DIETMAR MUELLER KAMMERHOFWEG 12P RIEDSTADT, 65460
8 NOBORU TAKAHASHI WEISSKIRCHENER WEG 31, FRANKFURT AM MAIN 60439
PCT International Classification Number F02M63/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 11/552610 2006-10-25 U.S.A.