U.S. patent application number 12/431153 was filed with the patent office on 2010-10-28 for diagnostic system for spark ignition direct injection system control circuits.
This patent application is currently assigned to GM GLOBAL TECHNOLOGY OPERATIONS, INC.. Invention is credited to Mark D. Carr, Hamid M. Esfahan, Daniel P. Grenn, Michael J. Lucido, Ian J. Mac Ewen, Jon C. Miller, John F. Van Gilder, Wenbo Wang.
Application Number | 20100269793 12/431153 |
Document ID | / |
Family ID | 42991001 |
Filed Date | 2010-10-28 |
United States Patent
Application |
20100269793 |
Kind Code |
A1 |
Wang; Wenbo ; et
al. |
October 28, 2010 |
DIAGNOSTIC SYSTEM FOR SPARK IGNITION DIRECT INJECTION SYSTEM
CONTROL CIRCUITS
Abstract
An engine control system includes a driver module and a
diagnostics module. The driver module includes a high-side driver
and a low-side driver, which selectively actuate a load. The driver
module generates status signals based on detection of each of a
plurality of failure modes of the high-side and low-side drivers.
The diagnostics module increments a first error count for a first
mode of the plurality of failure modes when the status signals
indicate the driver module has detected the first mode. The
diagnostics module increments a corresponding total count each time
the driver module analyzes the first mode. The diagnostics module
sets a fail state for a diagnostic trouble code (DTC) when the
first error count for the first mode reaches a first predetermined
threshold prior to the total count reaching a second predetermined
threshold.
Inventors: |
Wang; Wenbo; (Novi, MI)
; Carr; Mark D.; (Fenton, MI) ; Lucido; Michael
J.; (Northville, MI) ; Miller; Jon C.;
(Fenton, MI) ; Van Gilder; John F.; (Webberville,
MI) ; Grenn; Daniel P.; (Ann Arbor, MI) ;
Esfahan; Hamid M.; (Ann Arbor, MI) ; Mac Ewen; Ian
J.; (White Lake, MI) |
Correspondence
Address: |
Harness Dickey & Pierce, P.L.C.
P.O. Box 828
Bloomfield Hills
MI
48303
US
|
Assignee: |
GM GLOBAL TECHNOLOGY OPERATIONS,
INC.
Detroit
MI
|
Family ID: |
42991001 |
Appl. No.: |
12/431153 |
Filed: |
April 28, 2009 |
Current U.S.
Class: |
123/490 ;
318/490; 701/107 |
Current CPC
Class: |
F02D 41/221 20130101;
Y02T 10/40 20130101; F02D 2041/2093 20130101; F02D 41/20 20130101;
F02D 2041/2089 20130101 |
Class at
Publication: |
123/490 ;
318/490; 701/107 |
International
Class: |
F02M 51/00 20060101
F02M051/00; H02H 3/04 20060101 H02H003/04; F02D 41/30 20060101
F02D041/30 |
Claims
1. An engine control system comprising: a driver module that
includes a high-side driver and a low-side driver, wherein the
high-side and low-side drivers selectively actuate a load, wherein
the driver module analyzes a plurality of failure modes of the
high-side and low-side drivers, and wherein the driver module
generates status signals based on detection of each of the
plurality of failure modes; and a diagnostics module that stores a
first error count for each of the plurality of failure modes and
that stores a total count, wherein the diagnostics module
increments the first error count for a first mode of the plurality
of failure modes when the status signals indicate that the driver
module has detected the first mode, wherein the diagnostics module
increments the total count each time the driver module analyzes the
first mode, and wherein the diagnostics module sets a fail state
for a diagnostic trouble code (DTC) when the first error count for
the first mode reaches a first predetermined threshold prior to the
total count reaching a second predetermined threshold.
2. The engine control system of claim 1 wherein the load comprises
a fuel injector and wherein the high-side and low-side drivers
selectively actuate the load based on a desired fuel mass.
3. The engine control system of claim 1 wherein the load comprises
a solenoid that is implemented in a fuel pump, and wherein the
high-side and low-side drivers selectively actuate the load based
on a desired fuel pressure.
4. The engine control system of claim 1 further comprising a
plurality of driver pairs, wherein each driver pair includes a
low-side driver and a high-side driver, and wherein the diagnostics
module stores an error count for each of the plurality of failure
modes for each of the plurality of driver pairs.
5. The engine control system of claim 4 wherein each of the
plurality of driver pairs actuates a fuel injector, wherein the
load comprises a solenoid that is implemented in a fuel pump, and
wherein the high-side and low-side drivers selectively actuate the
load based on a desired fuel pressure.
6. The engine control system of claim 4 wherein the diagnostics
module selectively sets the fail state for a distinct DTC for each
of the plurality of failure modes for each of the plurality of
driver pairs.
7. The engine control system of claim 1 wherein the diagnostics
module selectively sets the fail state for a distinct DTC for each
of the plurality of failure modes.
8. The engine control system of claim 1 wherein the diagnostics
module stores a plurality of total counts including the total
count, wherein each of the plurality of total counts corresponds to
one of the plurality of failure modes.
9. The engine control system of claim 8 wherein the diagnostics
module stores a plurality of first predetermined thresholds
including the first predetermined threshold and stores a plurality
of second predetermined thresholds including the second
predetermined threshold, wherein each of the plurality of first
predetermined thresholds corresponds to one of the plurality of
failure modes, and wherein each of the plurality of second
predetermined thresholds corresponds to one of the plurality of
failure modes.
10. The engine control system of claim 1 wherein the diagnostics
module selectively performs remedial action based on the state of
the DTC.
11. A method comprising: selectively actuating a load using a
high-side driver and a low-side driver; analyzing a plurality of
failure modes of the high-side and low-side drivers; generating
status signals based on detection of each of the plurality of
failure modes; storing a first error count for each of the
plurality of failure modes; storing a total count for each of the
plurality of failure modes; incrementing the first error count for
a first mode of the plurality of failure modes when the status
signals indicate that the first mode has been detected;
incrementing the total count for the first mode each time the
status signals indicated that the first mode has been analyzed; and
setting a fail state for a diagnostic trouble code (DTC) when the
first error count for the first mode reaches a first predetermined
threshold prior to the total count reaching a second predetermined
threshold.
12. The method of claim 11 wherein the load comprises a fuel
injector and further comprising selectively actuating the load
using the high-side and low-side drivers based on a desired fuel
mass.
13. The method of claim 11 wherein the load comprises a solenoid
that is implemented in a fuel pump, and further comprising
selectively actuating the load using the high-side and low-side
drivers based on a desired fuel pressure.
14. The method of claim 11 further comprising: selectively
actuating a plurality of loads using a plurality of driver pairs,
wherein each driver pair includes a low-side driver and a high-side
driver; and storing an error count for each of the plurality of
failure modes for each of the plurality of driver pairs.
15. The method of claim 14 wherein each of the plurality of driver
pairs actuates a fuel injector, wherein the load comprises a
solenoid that is implemented in a fuel pump, and further comprising
selectively actuating the load using the high-side and low-side
drivers based on a desired fuel pressure.
16. The method of claim 14 further comprising selectively setting
the fail state for a distinct DTC for each of the plurality of
failure modes for each of the plurality of driver pairs.
17. The method of claim 11 further comprising selectively setting
the fail state for a distinct DTC for each of the plurality of
failure modes.
18. The method of claim 11 further comprising storing a plurality
of total counts including the total count, wherein each of the
plurality of total counts corresponds to one of the plurality of
failure modes.
19. The method of claim 18 further comprising: storing a plurality
of first predetermined thresholds including the first predetermined
threshold; and storing a plurality of second predetermined
thresholds including the second predetermined threshold, wherein
each of the plurality of first predetermined thresholds corresponds
to one of the plurality of failure modes, and wherein each of the
plurality of second predetermined thresholds corresponds to one of
the plurality of failure modes.
20. The method of claim 11 further comprising selectively
performing remedial action based on the state of the DTC.
Description
FIELD
[0001] The present disclosure relates to fuel injection systems and
more particularly to improved diagnostic systems and methods for
detecting fuel injection system failures.
BACKGROUND
[0002] The background description provided herein is for the
purpose of generally presenting the context of the disclosure. Work
of the presently named inventors, to the extent it is described in
this background section, as well as aspects of the description that
may not otherwise qualify as prior art at the time of filing, are
neither expressly nor impliedly admitted as prior art against the
present disclosure.
[0003] In a spark ignition direct injection (SIDI) system, highly
pressurized fuel is injected via a common fuel rail directly into a
combustion chamber of each cylinder in an engine. The SIDI design
may provide a more efficient distribution of an air/fuel mixture in
the cylinders than conventional multi-port fuel injection, which
injects fuel near intake ports of the cylinders. More efficient
air/fuel distribution may provide improved fuel efficiency, higher
power output, and reduced emission levels at low load
conditions.
[0004] An onboard diagnostic (OBD) system monitors the individual
components of the SIDI system and records errors detected with any
of the individual components. Diagnostic trouble codes (DTCs) for
various errors and malfunctions may be predefined by standards,
such as second generation OBD (OBD-II). DTCs set by the OBD system
may be read by service tools owned by dealerships and/or repair
facilities. The OBD system may also notify an operator of the
vehicle when one or more DTCs have been set.
SUMMARY
[0005] An engine control system includes a driver module and a
diagnostics module. The driver module includes a high-side driver
and a low-side driver. The high-side and low-side drivers
selectively actuate a load. The driver module analyzes a plurality
of failure modes of the high-side and low-side drivers. The driver
module generates status signals based on detection of each of the
plurality of failure modes. The diagnostics module stores a first
error count for each of the plurality of failure modes and stores a
total count. The diagnostics module increments the first error
count for a first mode of the plurality of failure modes when the
status signals indicate the driver module has detected the first
mode. The diagnostics module increments the total count each time
the driver module analyzes the first mode. The diagnostics module
sets a fail state for a diagnostic trouble code (DTC) when the
first error count for the first mode reaches a first predetermined
threshold prior to the total count reaching a second predetermined
threshold.
[0006] A method includes selectively actuating a load using a
high-side driver and a low-side driver; analyzing a plurality of
failure modes of the high-side and low-side drivers; generating
status signals based on detection of each of the plurality of
failure modes; storing a first error count for each of the
plurality of failure modes; storing a total count for each of the
plurality of failure modes; incrementing the first error count for
a first mode of the plurality of failure modes when the status
signals indicate that the first mode has been detected;
incrementing the total count for the first mode each time the
status signals indicated that the first mode has been analyzed; and
setting a fail state for a diagnostic trouble code (DTC) when the
first error count for the first mode reaches a first predetermined
threshold prior to the total count reaching a second predetermined
threshold.
[0007] Further areas of applicability of the present disclosure
will become apparent from the detailed description provided
hereinafter. It should be understood that the detailed description
and specific examples are intended for purposes of illustration
only and are not intended to limit the scope of the disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The present disclosure will become more fully understood
from the detailed description and the accompanying drawings,
wherein:
[0009] FIG. 1 is a functional block diagram illustrating an
exemplary vehicle power system according to the principles of the
present disclosure;
[0010] FIG. 2 is a schematic diagram illustrating an exemplary
engine control system of the vehicle power system according to the
principles of the present disclosure;
[0011] FIG. 3 is a schematic diagram illustrating an exemplary
implementation of the injector/fuel system module of the engine
control module of FIG. 2 according to the principles of the present
disclosure;
[0012] FIG. 4A is a schematic diagram illustrating an exemplary
implementation of the diagnostics module of the engine control
module of FIG. 2 according to the principles of the present
disclosure;
[0013] FIG. 4B is a diagram illustrating exemplary data stored in
the storage module of FIG. 4A according to the principles of the
present disclosure; and
[0014] FIG. 5 is a flowchart of an exemplary implementation of the
diagnostics module according to the present disclosure.
DETAILED DESCRIPTION
[0015] The following description is merely exemplary in nature and
is in no way intended to limit the disclosure, 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 phrase at least one of A, B, and C should be construed to mean
a logical (A or B or C), using a non-exclusive logical or. It
should be understood that steps within a method may be executed in
different order without altering the principles of the present
disclosure.
[0016] 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 execute one
or more software or firmware programs, a combinational logic
circuit, and/or other suitable components that provide the
described functionality.
[0017] Referring now to FIG. 1, a functional block diagram of a
vehicle power system 10 is shown. The power system 10 includes an
intake system 12, an engine 14, an engine control module (ECM) 16,
a spark ignition direct injection (SIDI) fuel system 18, and an
exhaust system 20. In the intake system 12, air passing through a
throttle valve 22 is drawn into an intake manifold 24. Based on
signals from the ECM 16, the throttle valve 22 regulates the volume
of air drawn into the intake manifold 24.
[0018] The intake manifold 24 distributes the air to N combustion
chambers 26 located in the engine 14. Although FIG. 1 depicts the
engine 14 having six combustion chambers 26 (N=6), the engine 14
may include additional or fewer chambers 26. For example only, the
engine 14 may include from 1 to 16 chambers. The functions of the
ECM 16 can be incorporated with functions of a transmission control
module (not shown) into a single powertrain control module.
[0019] The air in the combustion chambers 26 combusts with a
metered amount of fuel supplied directly to the combustion chambers
26 by the SIDI fuel system 18. In the SIDI fuel system 18, fuel
from a fuel tank 28 is pumped to a first pressure (e.g., 0.3-0.6
MegaPascals) by a low pressure pump 30.
[0020] The low pressure pump 30 provides the fuel to a high
pressure pump 32 that pumps the fuel to a second pressure (e.g.,
2-26 MegaPascals). The fuel pressurized to the second pressure is
provided to fuel injectors 34 via fuel rails 36 for injection into
the combustion chambers 26. The ECM 16 may vary the output of the
fuel injectors 34 to optimize performance of the engine 14. For
example, the ECM 16 may decrease the amount of fuel injected
(leaner air/fuel ratio) at light-load conditions to lower exhaust
emission levels.
[0021] Conversely, in a full power mode (e.g., during rapid
acceleration or with heavy loads), the ECM 16 may increase the
amount of fuel injected (richer air/fuel ratio) to optimize engine
performance. While the SIDI fuel system 18 is shown with the single
high pressure pump 32 supplying the fuel rails 36, the SIDI fuel
system 18 may include any combination of fuel pumps and fuel rails
to supply fuel to the fuel injectors 34. For example, in
applications having high fuel demands, one or more dedicated fuel
pumps may be implemented for each rail in a multiple rail system.
The combustion of the air/fuel mixture reciprocally drives pistons
38 located within the combustion chambers 26 to drive a crankshaft.
Power from the crankshaft is used to propel the vehicle. Waste
exhaust gases from the combustion process are conveyed away from
the engine 14 through the exhaust system 20.
[0022] Referring now to FIG. 2, a functional block diagram of the
engine control module (ECM) 16 is shown including a fuel control
module 39, an injector module 40, a fuel system module 42, and a
diagnostics module 44. The fuel control module 39 determines a
desired air/fuel ratio corresponding to the desired performance
characteristics. The fuel control module 39 converts the desired
air/fuel ratio into a desired fuel mass. The injector module 40
controls the amount of fuel injected by the fuel injectors 34 to
achieve the desired fuel mass.
[0023] The injector module 40 may control the amount of fuel
injected by controlling the amount of time that the fuel injectors
34 are open. With a constant fuel pressure in the fuel rails 36,
the time that the fuel injectors 34 are open determines the amount
of fuel injected. The fuel system module 42 maintains the fuel
pressure in the fuel rails 36 at an approximately constant level.
For example only, fuel system module 42 may maintain the fuel
pressure to within a predetermined percentage of a desired fuel
pressure.
[0024] Each of the fuel injectors 34 may include a low side and a
high side input. The injector module 40 may therefore include a
low-side driver 46 and a high-side driver 48 corresponding to each
of the fuel injectors 34. The drivers 46, 48 may be switched "ON"
and "OFF" using pulse-width modulation (PWM). In various
implementations, the injector module 40 may control the duty cycle
of the PWM signals to achieve the desired fuel mass.
[0025] The fuel system module 42 controls a solenoid 50 in the high
pressure pump 32 using a low-side driver 52 and a high-side driver
54. The fuel system module 42 receives feedback from a fuel rail
sensor 56 indicating the fuel pressure in the fuel rail 36. The
drivers 52, 54 are switched "ON" and "OFF" to open or close the
solenoid 50 to allow fuel to flow from the low pressure pump 30 of
FIG. 1 to a fuel line 58.
[0026] The high pressure pump 32 may include a piston-style pump
that includes a first check valve 60, a piston 62, and a second
check valve 64. An end of the piston 62 is located in a chamber 66.
A cam 68 presses the piston 62 from a first position to a second
position, which decreases the volume of the chamber 66. Any fuel in
the chamber 66 is therefore pushed through the second check valve
64 into the fuel line 58. For example only, the cam 68 may be
rotated by a valvetrain camshaft (not shown) or by an electric
motor (not shown).
[0027] The piston 62 is returned to the second position by a device
such as a spring 70. This increases the volume in the chamber 66,
thereby lowering the pressure. When the solenoid 50 is open, the
pressure differential in the chamber 66 results in fuel flowing
into the chamber from the first check valve 60. A mechanical relief
valve 71 may allow fuel to flow from the fuel line 58 to the low
pressure side of the high pressure pump 32 when pressure in the
fuel line 58 increases above a threshold. In various
implementations, the fuel system module 42 may synchronize the
opening and closing of the solenoid 50 with the position of the cam
68.
[0028] Referring now to FIG. 3, a schematic diagram of an exemplary
implementation of the drivers 46, 48, 52, 54 is shown. In the
low-side driver 46, 52, a switch 72 selectively allows current to
flow from a load 74 to a low potential, such as ground or 12 V. In
the high-side driver 48, 54, a switch 73 selectively allows current
to flow from a power supply to the load 74. In various
implementations, a voltage of the power supply may be varied, such
as by selecting one of two power supply voltages. In various
implementations, the two power supply voltages may be 12 V and 65
V. In various implementations, the switches 72 and 73 may be
solid-state switches, such as metal-oxide semiconductor
field-effect transistors (MOSFETs).
[0029] The load 74 connects to the high-side driver 48, 54 via a
high-side output (HSO) and connects to the low-side driver 46, 52
via a low-side output (LSO). The load 74 is driven by both the
high-side driver 48, 54 and the low-side driver 46, 52 to allow for
high sped switching. Potential failure modes for the high-side
drivers 48, 54 include the HSO being open (disconnected), the HSO
being shorted to the ground potential, and the HSO being shorted to
the power supply. Similarly, failure modes for the low-side drivers
46, 52 include the LSO being open, shorted to the ground potential,
and shorted to the power supply. A further failure mode includes a
short circuit between the HSO and the LSO inside the load 74.
Therefore, each pair of high and low-side drivers may evidence at
least seven failure modes.
[0030] Referring now to FIG. 4A, an exemplary implementation of the
diagnostics module 44 is shown. The injector module 40 determines
when one of the above failure modes is present in any of the
low-side drivers 46 or the high-side drivers 48. The fuel system
module 42 determines when one of the above failure modes is present
in the low-side driver 52 or the high-side driver 54. For example
only, the injector module 40 may measure currents and/or voltages
at various locations of the low-side driver 46 and the high-side
driver 48 of one of the fuel injectors 34 in order to detect
various failure modes.
[0031] The diagnostics module 44 records data pertaining to the
detected failure modes, analyzes the recorded data, and makes
PASS/FAIL decisions based on the analysis. For example only, the
diagnostics module 44 includes a parsing module 75, a storage
module 76, a comparison module 78, a calibration module 80, a
remedial action module 82, and a timer module 84. The parsing
module 75 receives status signals from the injector module 40 and
the fuel system module 42 indicating which failures have been
detected and/or whether no failures have been detected.
[0032] For example only, seven failure modes may be defined for
each low/high-side driver pair, as described above and shown in
FIG. 4B. Although seven failure modes are shown, some or all of the
low/high-side driver pairs may have more or fewer failure modes
defined. When six fuel injectors 34 are present, such as for a
six-cylinder engine, and a pump solenoid is controlled with a
low/high-side driver pair, there are 7 total low/high-side driver
pairs. Therefore, 49 failure modes may be recorded--7 failure modes
for each of the 7 driver pairs.
[0033] Referring now to FIG. 4B, an exemplary storage table 86
stored in the storage module 76 is shown. Each storage location of
the storage table 86 may correspond to one of the failure modes
being detected for one of the low/high-side driver pairs. Each
storage location may include two values, named X and Y. The X value
tracks the number of times a failure mode was detected, while the Y
value tracks the total number of detection cycles. In other
implementations, each storage location includes an X value, while
one or more common Y values are stored. For example, a single Y
value may be stored for the entire storage table 86. Alternatively,
different Y values may be stored for each failure mode, with each Y
value being common across all of the low/high-side driver pairs for
that failure mode.
[0034] In various implementations, whether a given failure mode is
present for a given low/high-side driver pair may be determined
periodically, such as every 12.5 ms, every 62.5 ms, or every 100
ms. The period between determinations may be different for each
low/high-side driver pair and each failure mode. For purposes of
illustration, refer to a storage location 88 for a failure mode of
the low side output (LSO) being open for fuel injector C. The
values in storage location 88 indicate that 40 faults have been
detected (X=40) in 100 detection cycles (Y=100). In other words,
the LSO open failure mode was detected in 40% of the 100 detection
cycles. Shown as further illustration, injector A had an LSO open
failure mode for 100% of the last 40 detection cycles, while
injector E had an LSO open failure mode for 20% of the last 50
detection cycles.
[0035] Referring back to FIG. 4A, the timer module 84 may determine
how often failure mode data is read by the parsing module 75. The
timer module 84 may provide different timing signals for different
failure modes depending on how often checks are performed for
presence of the respective failure modes. Each time the parsing
module 75 receives an indication of whether or not a failure mode
is present, the parsing module 75 increments the Y value in the
corresponding storage location of the storage module 76. If the
failure mode was present, the parsing module 75 increments the X
value in the corresponding storage location of the storage module
76.
[0036] The comparison module 78 analyzes the data stored in the
storage module 76. For example only, the comparison module 78 may
compare the X and Y values of each storage location to
predetermined thresholds. These thresholds may be stored in a
calibration module 80 and may be set independently for each failure
mode and each low/high-side driver pair. In various
implementations, the thresholds for a given failure mode may be set
equal for all low/high-side driver pairs.
[0037] For example only, a selected storage location may have a
first predetermined threshold for the X value and a second
predetermined threshold for the Y value. When the Y value of a
storage location reaches the second predetermined threshold, the
comparison module 78 may reset the X and Y values in the storage
location to 0. However, when the Y value has not yet reached the
second predetermined threshold but the X value reaches the first
predetermined threshold, the comparison module 78 may set a
diagnostic trouble code (DTC). The DTC is transmitted to the
remedial action module 82.
[0038] As an illustration, consider a case where the first
predetermined threshold is 40 and the second predetermined
threshold is 100. This corresponds to a 40% threshold, above which
a DTC will be set. If the Y value reaches 100 before the X value
reaches 40, the percentage of failure mode detection will be less
than 40%. The DTC is set to a pass state, and both X and Y are
reset for another series of measurements. However, if the X values
reaches 40 at any time up to and including when the Y value reaches
100, the percentage of failure mode detection is 40% or greater.
The DTC is set to a fail state, and both X and Y are reset for
another series of measurements.
[0039] Separate DTCs may be assigned to each failure mode for each
low/high-side driver pair. The remedial action module 82 may record
the total number of each DTC generated by the comparison module 78.
The remedial action module 82 may also record information about
when the DTCs were generated. The remedial action module 82 may
provide this stored information to diagnostic devices, such as
OBD-II scan tools.
[0040] Further, the remedial action module 82 may provide feedback
to an operator of the vehicle, such as by illuminating an indicator
light or outputting a message to a display. Further, the remedial
action module 82 may instruct vehicle systems to perform various
remedial actions. For example only, the remedial actions selected
may be based on which type and how many of the DTCs are
received.
[0041] The remedial action module 82 may reduce the upper limit of
power output of the engine. The remedial action module 82 may
reduce the maximum allowed air/fuel mixture richness (equivalent to
increasing the lower limit on air/fuel ratio). The remedial action
module 82 may limit the opening of the throttle valve 22 to a range
of positions or to a predetermined position. The remedial action
module 82 may halt the provision of fuel to one or more cylinders
38. The remedial action module 82 may shutdown the engine 14, which
may include halting provision of fuel to all of the cylinders 38
and/or stopping the provision of spark to all of the cylinders
38.
[0042] Referring now to FIG. 5, a flowchart depicts exemplary
operation of the diagnostics module 44 of FIG. 4A. Control may
begin when the engine 14 is started. Control begins in step 102,
where control clears the X and Y values for each of the storage
locations in the storage module 76. Control continues in step 104,
where control receives fault information from the fuel system
module 42 and the injector module 40.
[0043] Control continues in step 106, where control determines
whether a timer signal has been generated by the timer module 84.
If so, control transfers to step 108; otherwise, control returns to
step 104. The timer signal received in step 106 may correspond to
one or more of the storage locations of the storage module 76.
[0044] For example only, all failure modes for all low/high-side
driver pairs are determined on a common periodic schedule. In this
case, the timer signal in step 106 indicates that the X and Y
values will be updated for all storage locations in the storage
module 76. Alternatively, the timer signal may apply to only
certain failure modes. For example only, failure modes that are
tested more frequently may correspond to a timer signal that is
generated more often. For example only, shorts to ground and to
power may be tested more frequently than open failure modes.
[0045] In step 108, control selectively increments X and Y values
for storage locations that correspond to the timer signal generated
in step 106. The Y values for each of the storage locations may be
incremented regardless of whether a fault was detected, while the X
values may be incremented when the corresponding failure mode of
the corresponding low/high-side driver pair is detected.
[0046] Control continues in step 110, where control determines
whether an X value of any of the updated storage locations is
greater than a corresponding predetermined threshold. If the X
value exceeds the corresponding threshold for one or more of the
storage locations, control transfers to step 112; otherwise,
control transfers to step 114.
[0047] The predetermined threshold may be stored by a calibration
module 80. As described above, the thresholds may be different
depending on the failure mode and the low/high-side driver pair to
which the storage location applies. In various implementations, the
calibration module 80 may include a table similar to the storage
table 86, where the X and Y values in each storage location
indicate the X and Y thresholds to apply to the storage table
86.
[0048] In step 114, control determines whether the Y value for any
of the storage locations updated in step 108 is greater than a
corresponding predetermined threshold. If so, control transfers to
step 116; otherwise, control returns to step 104. The Y thresholds
may also be stored by the calibration module 80. In various
implementations, the inequality in steps 110 and 114 may be a
greater than or equal to (.gtoreq.) instead of the greater than
(>). In step 116, control reports a pass state for a diagnostic
trouble code (DTC) to the remedial action module 82. The DTC
corresponds to the storage location identified in step 114 for
which the Y value is greater than the predetermined threshold.
[0049] Control continues in step 118, where remedial action is
selectively halted. For example, if remedial action had been
initiated based on the DTC that now has a pass state, the remedial
action may be halted. Alternatively, the previous remedial action
may be made less restrictive. For example only, an upper torque
limit may be increased when the DTC previously having a fail state
now has the pass state. Control continues in step 120, control
resets the X and Y values for the identified storage location and
control returns to step 104.
[0050] In step 112, control reports a fail state for a diagnostic
trouble code (DTC) to the remedial action module 82. The DTC
corresponds to the storage location identified in step 110 for
which the X value is greater than the predetermined threshold. When
multiple storage locations meet the criteria in step 110, multiple
fail state DTCs may be reported to the remedial action module step
112. Distinct DTCs may be defined for each storage location in the
storage table 86.
[0051] Control continues in step 122, where control selectively
performs predetermined remedial actions based upon the DTCs sent in
step 112. Whether remedial action is performed and which remedial
action or actions will be performed in step 122 may further be
determined by previous DTC information.
[0052] For example only, a first DTC for a first low/high-side
driver pair corresponding to a first fuel injector, where the
failure mode is a low-side output (LSO) open failure, may be logged
for retrieval by a service technician. However, additional
instances of the same DTC may trigger deactivation of the first
fuel injector. Deactivating the fuel injector may include
deactivating the associated cylinder and any other fuel injectors
serving the associated cylinder.
[0053] For example only, the selected remedial action may include
shutting down the engine 14 when a summation of DTCs across
multiple fuel injectors is greater than a threshold number. After
performing and/or initiating the predetermined remedial action,
control continues in step 120, where the X and Y values for the
storage locations identified in step 110 are reset.
[0054] The broad teachings of the disclosure can be implemented in
a variety of forms. Therefore, while this disclosure includes
particular examples, the true scope of the disclosure should not be
so limited since other modifications will become apparent to the
skilled practitioner upon a study of the drawings, the
specification, and the following claims.
* * * * *