U.S. patent application number 11/857472 was filed with the patent office on 2009-03-19 for intake charge deficit method for engine real-time diagnostics application.
This patent application is currently assigned to Detroit Diesel Corporation. Invention is credited to Zhiping Han.
Application Number | 20090076715 11/857472 |
Document ID | / |
Family ID | 40384454 |
Filed Date | 2009-03-19 |
United States Patent
Application |
20090076715 |
Kind Code |
A1 |
Han; Zhiping |
March 19, 2009 |
INTAKE CHARGE DEFICIT METHOD FOR ENGINE REAL-TIME DIAGNOSTICS
APPLICATION
Abstract
The present invention relates to a method of engine operation to
provide a real time engine diagnostic to detect EGR, turbocharger
or compressor malfunctions and to prevent such malfunctions from
damaging the engine.
Inventors: |
Han; Zhiping; (La Salle,
CA) |
Correspondence
Address: |
RADER, FISHMAN & GRAUER PLLC
39533 WOODWARD AVENUE, SUITE 140
BLOOMFIELD HILLS
MI
48304-0610
US
|
Assignee: |
Detroit Diesel Corporation
Detroit
MI
|
Family ID: |
40384454 |
Appl. No.: |
11/857472 |
Filed: |
September 19, 2007 |
Current U.S.
Class: |
701/115 |
Current CPC
Class: |
F02D 41/0007 20130101;
F02D 41/18 20130101; F02D 41/221 20130101; F02D 41/10 20130101;
F02D 41/0065 20130101; F02M 26/05 20160201; Y02T 10/12 20130101;
Y02T 10/40 20130101; F02D 2250/38 20130101; Y02T 10/47 20130101;
Y02T 10/144 20130101 |
Class at
Publication: |
701/115 |
International
Class: |
F02D 28/00 20060101
F02D028/00 |
Claims
1. A method to operate an internal combustion engine to provide
real time diagnostics to detect hardware failures, said internal
combustion engine having electronic sensors in communication with
said electronic control central unit with memory, unit and variable
engine system components including an exhaust gas recirculation
valve, said method comprising: determining a target intake air flow
rate based upon target engine operation during exhaust smoke
control time period; determining an actual air intake flow rate
based upon actual sensed engine operation during said exhaust smoke
control time period; determining an air mass deficit as an
accumulated air intake charge quantity difference between the
targeted intake air flow and the actual intake air flow charge
during the exhaust smoke control time period according to the
formula: Air_mass _defict = .intg. smoke_control _start
smoke_control _end [ ( target_air _flow _rate ) - ( actual_air
_flow _rate ) ] t ##EQU00002##
2. The method of claim 1, wherein said smoke control period occurs
when engine fueling is limited because of an air intake shortage
while engine torque value is below maximum available engine torque
value.
3. The method of claim 1, wherein when the intake air mass flow
mass deficit exceeds a threshold, at least one of a fault in
flagged engine is derated, and a warning is activated to alert
operator of fault to protect at least in the ECU one of the engine
or engine system components from damage.
4. The method of claim 1, wherein when the air mass flow intake
value is operated then an air intake reference value stored in the
ECU for the engine during a given operation, a hardware failure
causing intake air quality degredation during acceleration is
indicated.
5. The method of claim 4 wherein said hardware failure is
indicative of at least one of EGR valve stick at least partially
open, a turbocharger malfunction, or a compressor malfunction, or
EGR loop exhaust leakage, or intake air flow leakage.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a method of engine
operation to provide a real time engine diagnostic to detect
malfunctions covered by hardware failure that may cause the engine
or its components to be damaged, or their performance to be
degraded, or the engine exhaust emissions to be non-compliant.
[0003] The present invention is further related to a method of
engine operation to provide a real time engine diagnostic to detect
EGR, turbocharger or compressor malfunctions and to prevent such
malfunctions from damaging the engine.
[0004] 2. Description of the Related Art
[0005] Kreso, U.S. Pat. No. 6,588,210 discloses the system and
method for measuring the flow rate of recirculated exhaust gas in
the compression ignition engine including a plurality of engine
sensors having outputs indicative of current engine condition and a
turbocharger. The system includes an exhaust gas recirculation
valve mounted in the exhaust pipe upstream of the turbocharger for
diverting a selectable portion of the exhaust gas for recirculation
in combination with the charge air, one or more sensors for sensing
current conditions of the recirculated exhaust gas, including
temperature and pressure, one or more sensors for sensing current
conditions of the intake air, and control logic for determining the
flow rate of the recirculated exhaust gas as a function of the
sensed conditions. In one embodiment, the system includes an
obstruction in the flow path of the recirculated exhaust gas and a
different pressure sensor for determining the pressure differential
between a point upstream of the obstruction and a point downstream
as the obstruction and control logic for determining the flow rate
of the recirculated gas as a function of the current intake
manifold pressure, the recirculated exhaust gas temperature, and
the differential pressure drop across the obstruction.
[0006] In the differential pressure embodiment, the flow rate of
the recirculated gas is determined from the voltage input from the
differential pressure sensor and from the sensed recirculated
exhaust gas temperature, according to the formula EGR flow rate
(KG/MIN) equals EGR gas density/density collection).sup.a*b*
(differential pressure drop, kPa).sup.c where the density
correction a, b, and c are each calibratable constants for a
particular orifice design.
SUMMARY OF THE INVENTION
[0007] The present invention is a method to operate an internal
combustion engine to provide real time diagnostics to detect
hardware failures, said internal combustion engine having
electronic sensors in communication with said electronic control
central unit with memory, unit and variable engine system
components including an exhaust gas recirculation valve. The method
comprises determining a target intake air flow rate based upon
target engine operation during exhaust smoke control time period;
determining an actual air intake flow rate based upon actual sensed
engine operation during said exhaust smoke control time period; and
determining an air mass deficit as an accumulated air intake charge
quantity difference between the targeted intake air flow and the
actual intake air flow charge during the exhaust smoke control time
period according to the formula:
Air_mass _defict = .intg. smoke_control _start smoke_control _end [
( target_air _flow _rate ) - ( actual_air _flow _rate ) ] t
##EQU00001##
The smoke control period occurs when engine fueling is limited
because of an air intake shortage while engine torque value is
below maximum available engine torque value. In addition, if the
air mass deficit value exceeds a threshold, at least one of a fault
in flagged engine is derated, and a warning is activated to alert
operator of fault to protect at least in the ECU one of the engine
or engine system components from damage. When the air mass deficit
value is operated then a threshold value stored in the ECU for the
engine during a given operation, a hardware failure causing intake
air quality degredation during acceleration is indicated. The
hardware failure is indicative of at least one of EGR valve stick
at least partially open, a turbocharger malfunction, or a
compressor malfunction, or EGR loop exhaust gas leakage, or intake
air flow leakage.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a schematic representation of an internal
combustion engine, various component systems and an electronic
control unit;
[0009] FIG. 2 is a graph representing EGR value position comparison
in FTP; and
[0010] FIG. 3 is a schematic representation of a software flow
chart of one method according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
[0011] FIG. 1 illustrates a vehicle powertrain system 10 in
accordance with one non-limiting aspect of the present invention.
The system 10 may provide power for driving any number of vehicles,
including on-highway trucks, construction equipment, marine
vessels, stationary generators, automobiles, trucks,
tractor-trailers, boats, recreational vehicle, light and heavy-duty
work vehicles, and the like.
[0012] The system 10 may be referred to as an internal combustion
driven system wherein fuels, such as gasoline and diesel fuels, are
burned in a combustion process to provide power, such as with a
spark or compression ignition engine 14. The engine 14 may be a
diesel engine that includes a number of cylinders 18 into which
fuel and air are injected for ignition as one skilled in the art
will appreciate. The engine 14 may be a multi-cylinder compression
ignition internal combustion engine, such as a 4, 6, 8, 12, 16, or
24 cylinder diesel engines, for example. It should be noted,
however, that the present invention is not limited to a particular
type of engine or fuel.
[0013] Exhaust gases generated by the engine 14 during combustion
may be emitted through an exhaust system 20. The exhaust system 20
may include any number of features, including an exhaust manifold
and passageways to deliver the emitted exhaust gases to a
particulate filter assembly 30, which in the case of diesel engines
is commonly referred to as a diesel particulate filter. Optionally,
the system 20 may include a turbocharger proximate the exhaust
manifold for compressing fresh air delivery into the engine 14. The
turbocharger, for example, may include a turbine 32 and a
compressor 34, such as a variable geometry turbocharger (VGT)
and/or a turbo compound power turbine. Of course, the present
invention is not limited to exhaust systems having turbochargers or
the like.
[0014] The particulate filter assembly 30 may be configured to
capture particulates associated with the combustion process. In
more detail, the particulate filter assembly 30 may include an
oxidation catalyst (OC) canister 36, which in includes an OC 38,
and a particulate filter canister 42, which includes a particulate
filter 44. The canisters 36, 42 may be separate components joined
together with a clamp or other feature such that the canisters 36,
42 may be separated for servicing and other operations. Of course,
the present invention is not intended to be limited to this
exemplary configuration for the particulate filter assembly 30.
Rather, the present invention contemplates the particulate filter
assembly including more or less of these components and features.
In particular, the present invention contemplates the particulate
filter assembly 30 including only the particulate filter 44 and not
necessarily the OC canister 36 or substrate 38 and that the
particulate filter 44 may be located in other portions of the
exhaust system 20, such as upstream of the turbine 32.
[0015] The OC 38, which for diesel engines is commonly referred to
as a diesel oxidation catalyst, may oxidize hydrocarbons and carbon
monoxide included within the exhaust gases so as to increase
temperatures at the particulate filter 44. The particulate filter
44 may capture particulates included within the exhaust gases, such
as carbon, oil particles, ash, and the like, and regenerate the
captured particulates if temperatures associated therewith are
sufficiently high. In accordance with one non-limiting aspect of
the present invention, one object of the particulate filter
assembly 30 is to capture harmful carbonaceous particles included
in the exhaust gases and to store these contaminates until
temperatures at the particulate filter 44 favor oxidation of the
captured particulates into a gas that can be discharged to the
atmosphere.
[0016] The OC and particulate filter canisters 36, 42 may include
inlets and outlets having defined cross-sectional areas with
expansive portions there between to store the OC 38 and particulate
filter 44, respectively. However, the present invention
contemplates that the canisters 36, 42 and devices therein may
include any number configurations and arrangements for oxidizing
emissions and capturing particulates. As such, the present
invention is not intended to be limited to any particular
configuration for the particulate filter assembly 30.
[0017] To facilitate oxidizing the capture particulates, a doser 50
may be included to introduce fuel to the exhaust gases such that
the fuel reacts with the OC 38 and combusts to increase
temperatures at the particulate filter 44, such as to facilitate
regeneration. For example, one non-limiting aspect of the present
invention contemplates controlling the amount of fuel injected from
the doser as a function of temperatures at the particulate filter
44 and other system parameters, such as air mass flow, ER
temperatures, and the like, so as to control regeneration. However,
the present invention also contemplates that fuel may be included
within the exhaust gases through other measures, such as by
controlling the engine 14 to emit fuel with the exhaust gases.
[0018] An air intake system 52 may be included for delivering fresh
air from a fresh air inlet 54 through an air passage to an intake
manifold for introduction to the engine 14. In addition, the system
52 may include an air cooler or charge air cooler 56 to cool the
fresh air after it is compressed by the compressor 34. Optionally,
a throttle intake valve 58 may be provided to control the flow of
fresh air to the engine 14. Optionally, the throttle intake valve
58 may also be provided to control the flow of EGR gases to the
engine 14 or control both fresh air and EGR gases 64 to the engine
14. The throttle valve 58 may be a manually or electrically
operated valve, such as one which is responsive to a pedal position
of a throttle pedal operated by a driver of the vehicle. There are
many variations possible for such an air intake system and the
present invention is not intended to be limited to any particular
arrangement. Rather, the present invention contemplates any number
of features and devices for providing fresh air to the intake
manifold and cylinders, including more or less of the foregoing
features.
[0019] An exhaust gas recirculation (EGR) system 64 may be
optionally provided to recycle exhaust gas to the engine 14 for
mixture with the fresh air. The ER system 64 may selectively
introduce a metered portion of the exhaust gasses into the engine
14. The EGR system 64, for example, may dilute the incoming air
charge and lower peak combustion temperatures to reduce the amount
of oxides of nitrogen produced during combustion. The amount of
exhaust gas to be recirculated may be controlled by controlling an
EGR valve 66 and/or in combination with other features, such as the
turbocharger. The EGR valve 66 may be a variable flow valve that is
electronically controlled. There are many possible configurations
for the controllable EGR valve 66 and embodiments of the present
invention are not limited to any particular structure for the EGR
valve 66.
[0020] The EGR system 64 in one non-limiting aspect of the present
invention may include an EGR cooler passage 70, which includes an
EGR cooler 72, and an ER cooler bypass 74. The EGR valve 66 may be
provided at the exhaust manifold to meter exhaust gas through one
or both of the EGR cooler passage 70 and bypass 74. Of course, the
present invention contemplates that the EGR system 64 may include
more or less of these features and other features for recycling
exhaust gas. Accordingly, the present invention is not intended to
be limited to any one EGR system and contemplates the use of other
such systems, including more or less of these features, such as an
EGR system having only one of the EGR cooler passage or bypass.
[0021] A cooling system 80 may be included for cycling the engine
14 by cycling coolant there through. The coolant may be sufficient
for fluidly conducting away heat generated by the engine 14, such
as through a radiator. The radiator may include a number of fins
through which the coolant flows to be cooled by air flow through an
engine housing and/or generated by a radiator fan directed thereto
as one skilled in the art will appreciated. It is contemplated,
however, that the present invention may include more or less of
these features in the cooling system 80 and the present invention
is not intended to be limited to the exemplary cooling system
described above.
[0022] The cooling system 80 may operate in conjunction with a
heating system 84. The heating system 84 may include a heating
core, a heating fan, and a heater valve. The heating core may
receive heated coolant fluid from the engine 14 through the heater
valve so that the heating fan, which may be electrically
controllable by occupants in a passenger area or cab of a vehicle,
may blow air warmed by the heating core to the passengers. For
example, the heating fan may be controllable at various speeds to
control an amount of warmed air blown past the heating core whereby
the warmed air may then be distributed through a venting system to
the occupants. Optionally, sensors and switches 86 may be included
in the passenger area to control the heating demands of the
occupants. The switches and sensors may include dial or digital
switches for requesting heating and sensors for determining whether
the requested heating demand was met. The present invention
contemplates that more or less of these features may be included in
the heating system and is not intended to be limited to the
exemplary heating system described above.
[0023] A controller 92, such as an electronic control module or
engine control module, may be included in the system 10 to control
various operations of the engine 14 and other system or subsystems
associated therewith, such as the sensors in the exhaust, EGR, and
intake systems. Various sensors may be in electrical communication
with the controller via input/output ports 94. The controller 92
may include a microprocessor unit (MPU) 98 in communication with
various computer readable storage media via a data and control bus
100. The computer readable storage media may include any of a
number of known devices which function as read only memory 102,
random access memory 104, and non-volatile random access memory
106. A data, diagnostics, and programming input and output device
108 may also be selectively connected to the controller via a plug
to exchange various information therebetween. The device 108 may be
used to change values within the computer readable storage media,
such as configuration settings, calibration variables, instructions
for EGR, intake, and exhaust systems control and others.
[0024] The system 10 may include an injection mechanism 114 for
controlling fuel and/or air injection for the cylinders 18. The
injection mechanism 114 may be controlled by the controller 92 or
other controller and comprise any number of features, including
features for injecting fuel and/or air into a common-rail cylinder
intake and a unit that injects fuel and/or air into each cylinder
individually. For example, the injection mechanism 114 may
separately and independently control the fuel and/or air injected
into each cylinder such that each cylinder may be separately and
independently controlled to receive varying amounts of fuel and/or
air or no fuel and/or air at all. Of course, the present invention
contemplates that the injection mechanism 114 may include more or
less of these features and is not intended to be limited to the
features described above.
[0025] The system 10 may include a valve mechanism 116 for
controlling valve timing of the cylinders 18, such as to control
air flow into and exhaust flow out of the cylinders 18. The valve
mechanism 116 may be controlled by the controller 92 or other
controller and comprise any number of features, including features
for selectively and independently opening and closing cylinder
intake and/or exhaust valves. For example, the valve mechanism 116
may independently control the exhaust valve timing of each cylinder
such that the exhaust and/or intake valves may be independently
opened and closed at controllable intervals, such as with a
compression brake. Of course, the present invention contemplates
that the valve mechanism may include more or less of these features
and is not intended to be limited to the features described
above.
[0026] In operation, the controller 92 receives signals from
various engine/vehicle sensors and executes control logic embedded
in hardware and/or software to control the system 10. The computer
readable storage media may, for example, include instructions
stored thereon that are executable by the controller 92 to perform
methods of controlling all features and sub-systems in the system
10. The program instructions may be executed by the controller in
the MPU 98 to control the various systems and subsystems of the
engine and/or vehicle through the input/output ports 94. In
general, the dashed lines shown in FIG. 1 illustrate the optional
sensing and control communication between the controller and the
various components in the powertrain system. Furthermore, it is
appreciated that any number of sensors and features may be
associated with each feature in the system for monitoring and
controlling the operation thereof.
[0027] In one non-limiting aspect of the present invention, the
controller 92 may be the DDEC controller available from Detroit
Diesel Corporation, Detroit, Mich. Various other features of this
controller are described in detail in a number of U.S. patents
assigned to Detroit Diesel Corporation. Further, the controller may
include any of a number of programming and processing techniques or
strategies to control any feature in the system 10. Moreover, the
present invention contemplates that the system may include more
than one controller, such as separate controllers for controlling
system or sub-systems, including an exhaust system controller to
control exhaust gas temperatures, mass flow rates, and other
features associated therewith. In addition, these controllers may
include other controllers besides the DDEC controller described
above.
[0028] In accordance with one non-limiting aspect of the present
invention, the controller 92 or other feature, may be configured
for permanently storing emission related fault codes in memory that
is not accessible to unauthorized service tools. Authorized service
tools may be given access by a password and in the event access is
given, a log is made of the event as well as whether any changes
that are attempted to made to the stored fault codes. It is
contemplated that any number of faults may be stored in permanent
memory, and that preferably eight such faults are stored in
memory.
[0029] FIG. 2 shows an engine test conducted to check the
invention's capability to detect either excessive ER flow or
leakage. The test was conducted in two groups. The first group of
tests simulated excessive EGR flow. The second group of tests
simulated the EGR loop leakage. The transient FTP test was chosen
for this purpose. During the excessive EGR flow engine test, the
EGR valve was locked at different opening positions to simulate
stuck valve malfunction of failing to close during accelerations.
The EGR loop leakage test used by a by-pass valve inserted into the
EGR flow pipe and the EGR leaking rate was measured by how many
turns the by-pass valve was opened, not directly the leaking flow
rate measurement. The air mass deficit value with normally
functioning parts was used as baseline (reference) in data
comparison.
[0030] FIG. 2 shows the air mass deficit values of an engine
operation baseline 118, the value of an EGR value stuck fully open
120, EGR valve stuck 30% open 122, and 1.75 turns of EGR leaking
valve opening 124 respectively. As seen in FIG. 2, the peak values
of the air mass deficit increased with either a stuck open EGR
valve, or a leaking EGR loop and the peak value difference is
sufficient to detect if the engine is experiencing an air supply
shortage problem from failed parts. The first requirement is to
detect a fully to partially opened EGR loop that may cause
excessive EGR flow during acceleration, which in turn causes
reduced air flow during smoke control. The second requirement is to
detect the EGR leakage from the EGR loop out to the atmosphere.
[0031] FIG. 3 is a schematic representation of one method according
to the present invention. Method 126 is directed to one method from
the operation of an internal combustion engine. Step 128 is to
determine a target intake air flow based upon the target engine
operation during an exhaust smoke control period. In this regard,
it is contemplated that various target engine operations and
various target intake air flow values are kept in a table in memory
of the ECU. These are used during smoke control time periods that
usually happen during periods of acceleration and refer to an
engine control strategy used when fueling is limited for the reason
of air shortage while engine torque is below a maximum achievable
value. Step 130 is determining actual intake air flow valve based
upon actual engine operation during an exhaust smoke control time
period. Step 132 is determining an air mass flow deficit as an
accumulated air intake charge quantity difference between the
targeted intake air flow and the actual intake air flow charge
during the exhaust smoke control time period. Step 134 is
determining whether the air flow intake mass deficit value is
greater than the air intake mass deficit threshold value. If no,
the software loops back to step 128. If yes, step 136 is logging a
fault in the ECU, derating the engine to prevent any damage to the
engine or any component systems, and actuating a warning to alert
an operator of the fault.
[0032] While the invention has been described, those skilled in the
art understand that the words used herein are words of description,
and not words of limitation. Many variation and medications are
possible without departing from the scope and spirit of the
invention as set forth in the appended claims.
* * * * *