U.S. patent application number 16/387677 was filed with the patent office on 2020-10-22 for low speed pre-ignition knock detection, mitigation, and driver notification.
The applicant listed for this patent is William P. Attard, Ethan E Bayer, David A. Lawrence, Jonathan D. Stoffer, Tyler Tutton. Invention is credited to William P. Attard, Ethan E Bayer, David A. Lawrence, Jonathan D. Stoffer, Tyler Tutton.
Application Number | 20200332737 16/387677 |
Document ID | / |
Family ID | 1000004051414 |
Filed Date | 2020-10-22 |
United States Patent
Application |
20200332737 |
Kind Code |
A1 |
Bayer; Ethan E ; et
al. |
October 22, 2020 |
LOW SPEED PRE-IGNITION KNOCK DETECTION, MITIGATION, AND DRIVER
NOTIFICATION
Abstract
A low speed pre-ignition detection, mitigation, and driver
notification system and method utilize a controller to analyze a
knock signal from a knock sensor to detect LSPI knock of the engine
and in response to detecting the LSPI knock, enrich a fuel/air
ratio of the engine and limit a torque output of the engine to a
level that is less than a maximum torque output of the engine, and
when enriching the fuel/air ratio of the engine and limiting the
torque output of the engine does not mitigate the LSPI knock,
output at least one message for a driver of the vehicle instructing
the driver to take remedial action to mitigate the LSPI knock.
Inventors: |
Bayer; Ethan E; (Lake Orion,
MI) ; Stoffer; Jonathan D.; (Rochester Hills, MI)
; Lawrence; David A.; (Lake Orion, MI) ; Attard;
William P.; (Brighton, MI) ; Tutton; Tyler;
(Royal Oak, MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Bayer; Ethan E
Stoffer; Jonathan D.
Lawrence; David A.
Attard; William P.
Tutton; Tyler |
Lake Orion
Rochester Hills
Lake Orion
Brighton
Royal Oak |
MI
MI
MI
MI
MI |
US
US
US
US
US |
|
|
Family ID: |
1000004051414 |
Appl. No.: |
16/387677 |
Filed: |
April 18, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F02D 41/1498 20130101;
G07C 5/0816 20130101; F02D 2200/025 20130101; F02D 41/0007
20130101; F02D 2041/228 20130101; F02D 2250/26 20130101; F02D 41/22
20130101; B60W 50/14 20130101 |
International
Class: |
F02D 41/22 20060101
F02D041/22; F02D 41/14 20060101 F02D041/14; F02D 41/00 20060101
F02D041/00; G07C 5/08 20060101 G07C005/08 |
Claims
1. A low speed pre-ignition (LSPI) knock control system for an
engine of a vehicle, the control system comprising: a knock sensor
configured to generate a knock signal indicative of a vibration of
the engine caused by abnormal combustion; and a controller
configured to: receive the knock signal; analyze the knock signal
to detect low speed pre-ignition (LSPI) knock of the engine; in
response to detecting the LSPI knock, enrich a fuel/air ratio of
the engine and limit a torque output of the engine to a first
torque limit that is less than a maximum torque output of the
engine for a first period that defines a calibratable number of
engine power pulse (EPP) events; when enriching the fuel/air ratio
of the engine and limiting the torque output of the engine to the
first torque limit for the first period does not mitigate the LSPI
knock, limit the torque output of the engine to a second torque
limit for a second period defining a remainder of a key cycle of
the engine; when limiting the torque output of the engine to the
second torque limit for the second period does not mitigate the
LSPI knock, limit the torque output of the engine to a third torque
limit until a calibratable amount of fuel has been used by the
engine; and when enriching the fuel/air ratio of the engine and
limiting the torque output of the engine does not mitigate the LSPI
knock, output at least one message for a driver of the vehicle
instructing the driver to take remedial action to mitigate the LSPI
knock.
2. The control system of claim 1, wherein the message (i) instructs
the driver of the vehicle to supply at least one of a specific
quality of oil and a specific quality of fuel to the vehicle or
(ii) instructs the driver of the vehicle to take the vehicle to a
service center for service.
3-5. (canceled)
6. The control system of claim 1, wherein the controller is
configured to output a first message while limiting the torque
output of the engine to the third torque limit until the
calibratable amount of fuel has been used by the engine, wherein
the first message instructs the driver of the vehicle to provide at
least one of a specific quality of oil and a specific quality of
fuel to the vehicle.
7. The control system of claim 6, wherein when the torque output of
the engine is limited to the third torque limit until the
calibratable amount of fuel has been used by the engine occurs a
calibratable number of times, the controller is configured to
output a second message instructing the driver of the vehicle take
the vehicle to a service center for service.
8. The control system of claim 1, wherein the controller is
configured to output the at least one message to a display of the
vehicle for display to the driver of the vehicle.
9. The control system of claim 1, wherein the engine is a
turbocharged, direct injection (DI) engine.
10. A low speed pre-ignition (LSPI) knock detection, mitigation,
and driver notification method for a vehicle, the method
comprising: receiving, by a controller of the vehicle from a knock
sensor of the vehicle, a knock signal indicative of a vibration of
an engine of the vehicle caused by abnormal combustion; analyzing,
by the controller, the knock signal to detect LSPI knock of the
engine; in response to detecting the LSPI knock, enriching, by the
controller, a fuel/air ratio of the engine and limiting, by the
controller, a torque output of the engine to a first torque limit
that is less than a maximum torque output of the engine for a first
period defining a calibratable number of engine power pulse (EPP)
events; when enriching the fuel/air ratio of the engine and
limiting the torque output of the engine to the first torque limit
for the first period does not mitigate the LSPI knock, limiting, by
the controller, the torque output of the engine to a second torque
limit for a second period defining a remainder of a key cycle of
the engine; when limiting the torque output of the engine to the
second torque limit for the second period does not mitigate the
LSPI knock, limiting, by the controller, the torque output of the
engine to a third torque limit until a calibratable amount of fuel
has been used by the engine; and when enriching the fuel/air ratio
of the engine and limiting the torque output of the engine does not
mitigate the LSPI knock, outputting, by the controller, at least
one message for a driver of the vehicle instructing the driver to
take remedial action to mitigate the LSPI knock.
11. The method of claim 10, wherein the message (i) instructs the
driver of the vehicle to supply at least one of a specific quality
of oil and a specific quality of fuel to the vehicle or (ii)
instructs the driver of the vehicle to take the vehicle to a
service center for service.
12-14. (canceled)
15. The method of claim 10, wherein the controller outputs a first
message while limiting the torque output of the engine to the third
torque limit until the calibratable amount of fuel has been used by
the engine, wherein the first message instructs the driver of the
vehicle to provide at least one of a specific quality of oil and a
specific quality of fuel to the vehicle.
16. The method of claim 15, wherein when the torque output of the
engine is limited to the third torque limit until the calibratable
amount of fuel has been used by the engine occurs a calibratable
number of times, the controller outputs a second message
instructing the driver of the vehicle take the vehicle to a service
center for service.
17. The method of claim 10, wherein the controller outputs the at
least one message to a display of the vehicle for display to the
driver of the vehicle.
18. The method of claim 10, wherein the engine is a turbocharged,
direct injection (DI) engine.
Description
FIELD
[0001] The present application generally relates to engine knock
detection and, more particularly, to techniques for low speed
pre-ignition (LSPI) knock detection, mitigation, and driver
notification.
BACKGROUND
[0002] Internal combustion engines combust a fuel/air mixture
within cylinders to drive pistons that rotatably turn a crankshaft
to generate drive torque. Abnormal combustion of the fuel/air
mixture can cause vibration of the engine (e.g., seismic waves
through the engine structure), which is also known as "knock."
There are two primary types of engine knock: (1) end-gas
auto-ignition (also known as "spark knock") and (2) low speed
pre-ignition (LSPI) knock (also known as "mega knock"). LSPI knock
is a stochastic, abnormal start of combustion prior to spark
discharge. Possible causes of LSPI knock include cylinder hot spots
or oil ingestion, or chemical pre-reactions, each creating pressure
waves that collide causing the LSPI knock.
[0003] LSPI knock is often one or more orders of magnitude greater
in intensity than spark knock. A typical knock control strategy is
spark retardation. This control strategy, however, is not effective
against LSPI knock and is actually detrimental in mitigating LSPI
knock. This is because during LSPI knock, combustion has already
been initiated prior to the spark discharge, and thus retardation
of the spark timing provides the cylinder charge even more time for
auto-ignition to occur. Accordingly, while such knock detection and
control systems work for their intended purpose, there remains a
need for improvement in the relevant art.
SUMMARY
[0004] According to one example aspect of the invention, a control
system for an engine of a vehicle is presented. In one exemplary
implementation, the control system comprises: a knock sensor
configured to generate a knock signal indicative of a vibration of
the engine caused by abnormal combustion and a controller
configured to: receive the knock signal, analyze the knock signal
to detect low speed pre-ignition (LSPI) knock of the engine, in
response to detecting the LSPI knock, enrich a fuel/air ratio of
the engine and limit a torque output of the engine to a level that
is less than a maximum torque output of the engine, and when
enriching the fuel/air ratio of the engine and limiting the torque
output of the engine does not mitigate the LSPI knock, output at
least one message for a driver of the vehicle instructing the
driver to take remedial action to mitigate the LSPI knock.
[0005] In some implementations, the message (i) instructs the
driver of the vehicle to supply at least one of a specific quality
of oil and a specific quality of fuel to the vehicle or (ii)
instructs the driver of the vehicle to take the vehicle to a
service center for service.
[0006] In some implementations, in response to detecting the LSPI
knock, the controller is configured to enrich the fuel/air ratio of
the engine and limit the torque output of the engine to a first
torque limit for a calibratable number of engine power pulse (EPP)
events. In some implementations, when enriching the fuel/air ratio
of the engine and limiting the torque output of the engine to the
first torque limit for the first period does not mitigate the LSPI
knock, the controller is configured to limit the torque output of
the engine to a second torque limit for a remainder of a key cycle
of the engine. In some implementations, when limiting the torque
output of the engine to the second torque limit for the second
period does not mitigate the LSPI knock, the controller is
configured to limit the torque output of the engine to a third
torque limit until a calibratable amount of fuel has been used by
the engine.
[0007] In some implementations, the controller is configured to
output a first message while limiting the torque output of the
engine to the third torque limit until the calibratable amount of
fuel has been used by the engine, wherein the first message
instructs the driver of the vehicle to provide at least one of a
specific quality of oil and a specific quality of fuel to the
vehicle. In some implementations, when the torque output of the
engine is limited to the third torque limit until the calibratable
amount of fuel has been used by the engine occurs a calibratable
number of times, the controller is configured to output a second
message instructing the driver of the vehicle take the vehicle to a
service center for service.
[0008] In some implementations, the controller is configured to
output the at least one message to a display of the vehicle for
display to the driver of the vehicle. In some implementations, the
engine is a turbocharged, direct injection (DI) engine.
[0009] According to another example aspect of the invention, an
LSPI knock detection, mitigation, and driver notification method
for a vehicle is presented. In one exemplary implementation, the
method comprises: receiving, by a controller of the vehicle from a
knock sensor of the vehicle, a knock signal indicative of a
vibration of an engine of the vehicle caused by abnormal
combustion, analyzing, by the controller, the knock signal to
detect LSPI knock of the engine, in response to detecting the LSPI
knock, enriching, by the controller, a fuel/air ratio of the engine
and limiting, by the controller, a torque output of the engine to a
level that is less than a maximum torque output of the engine, and
when enriching the fuel/air ratio of the engine and limiting the
torque output of the engine does not mitigate the LSPI knock,
outputting, by the controller, at least one message for a driver of
the vehicle instructing the driver to take remedial action to
mitigate the LSPI knock.
[0010] In some implementations, the message (i) instructs the
driver of the vehicle to supply at least one of a specific quality
of oil and a specific quality of fuel to the vehicle or (ii)
instructs the driver of the vehicle to take the vehicle to a
service center for service.
[0011] In some implementations, in response to detecting the LSPI
knock, the controller enriches the fuel/air ratio of the engine and
limits the torque output of the engine to a first torque limit for
a calibratable number of EPP events. In some implementations, when
enriching the fuel/air ratio of the engine and limiting the torque
output of the engine to the first torque limit for the first period
does not mitigate the LSPI knock, the controller limits the torque
output of the engine to a second torque limit for a remainder of a
key cycle of the engine. In some implementations, when limiting the
torque output of the engine to the second torque limit for the
second period does not mitigate the LSPI knock, the controller
limits the torque output of the engine to a third torque limit
until a calibratable amount of fuel has been used by the
engine.
[0012] In some implementations, the controller outputs a first
message while limiting the torque output of the engine to the third
torque limit until the calibratable amount of fuel has been used by
the engine, wherein the first message instructs the driver of the
vehicle to provide at least one of a specific quality of oil and a
specific quality of fuel to the vehicle. In some implementations,
when the torque output of the engine is limited to the third torque
limit until the calibratable amount of fuel has been used by the
engine occurs a calibratable number of times, the controller
outputs a second message instructing the driver of the vehicle take
the vehicle to a service center for service.
[0013] In some implementations, the controller outputs the at least
one message to a display of the vehicle for display to the driver
of the vehicle. In some implementations, the engine is a
turbocharged DI engine.
[0014] Further areas of applicability of the teachings of the
present disclosure will become apparent from the detailed
description, claims and the drawings provided hereinafter, wherein
like reference numerals refer to like features throughout the
several views of the drawings. It should be understood that the
detailed description, including disclosed embodiments and drawings
referenced therein, are merely exemplary in nature intended for
purposes of illustration only and are not intended to limit the
scope of the present disclosure, its application or uses. Thus,
variations that do not depart from the gist of the present
disclosure are intended to be within the scope of the present
disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a diagram of an example engine according to the
principles of the present disclosure;
[0016] FIG. 2 is a plot of an example low speed pre-ignition (LSPI)
knock detection and mitigation process according to the principles
of the present disclosure; and
[0017] FIGS. 3A-3B are flow diagrams of an example LSPI knock
detection, mitigation, and driver notification method according to
the principles of the present disclosure.
DETAILED DESCRIPTION
[0018] As mentioned above, low speed pre-ignition (LSPI) knock
cannot be mitigated via conventional spark retardation. Because its
intensity is orders of magnitude higher than end-gas spark knock,
LSPI knock could potentially damage the engine, thereby increasing
vehicle warranty costs. In particular, LSPI knock often occurs in
smaller displacement engines having high compression ratios, such
as a turbocharged four-cylinder engine, particularly during high
load operation. In addition, if the incorrect oil and/or fuel is
provided to the engine, the probability of LSPI knock increases.
Oil grade, for example, may vary from region to region. Thus, there
remains a need for improved techniques for detecting and mitigating
LSPI knock and, in the event that the vehicle cannot mitigate the
LSPI knock, instructing the driver of the vehicle to provide the
proper oil and/or fuel to the engine and, if all of the above fails
to mitigate the LSPI knock, instructing the driver of the vehicle
to take the vehicle to a service center for service.
[0019] Referring now to FIG. 1, a diagram of a vehicle 100 having
an engine 104 is illustrated. The engine 104 is configured to
combust a fuel/air mixture to generate drive torque. Non-limiting
examples of the engine 104 include a spark ignition direct
injection (SIDI) engine, but it will be appreciated that the
techniques of the present disclosure could be applicable to any
suitable engine comprising a knock sensor, such as a port fuel
injection (PH) engine. In some implementations, the engine 104
could be a gasoline compression ignition engine (homogeneous charge
compression ignition (HCCI), partially pre-mixed charge compression
ignition (PPCI), pre-mixed charge compression ignition, etc.). The
engine 104 draws air into an intake manifold 108 through an
induction system 112 that is regulated by a throttle valve 116. The
air in the intake manifold 108 is distributed to a plurality of
cylinders 120 and therein combined with fuel injected by respective
DI fuel injectors 124. While four cylinders are shown, it will be
appreciated that the engine 100 could have any suitable number of
cylinders. In some implementations, the engine 104 includes a boost
system 122 (a turbocharger, a supercharger, etc.) having an
associated wastegate or surge valve 126 for regulating boost
pressure.
[0020] The fuel/air mixture in the cylinders 120 is compressed by
pistons (not shown) and combusted by spark generated by respective
spark plugs 128. For a smaller (e.g., 4 cylinder) configuration of
the engine 104 with the boost system 122, a compression ratio of
the cylinders 120 may be relatively high. The combustion of the
fuel/air mixture within the cylinders 120 drives the pistons (not
shown), which rotatably turn a crankshaft 132 to generate drive
torque. The drive torque is then transferred, e.g., via a
transmission (not shown), to a driveline 136. A knock sensor 140 is
configured to generate a knock signal indicative of vibration of
the engine 104 caused by abnormal combustion. In one exemplary
implementation, the knock sensor 140 is an accelerometer-based
sensor that is mounted to a block of the engine 104. The abnormal
combustion, if unaccounted for, causes noticeable vibrations
(noise, vibration, and/or harshness, or NVH) and/or could
potentially damage the engine 104. While one knock sensor 140 is
illustrated and discussed herein, it will be appreciated that the
engine 104 could include a plurality of distinct knock sensors (one
knock sensor per cylinder bank or group of cylinders, one knock
sensor per cylinder, etc.).
[0021] Exhaust gas resulting from combustion is expelled from the
cylinders 120 into an exhaust system 144 configured to treat the
exhaust gas before releasing it into the atmosphere. For example,
unburnt fuel from the abnormal combustion could cause increase
emissions that must then be handled by the exhaust system 144,
which could increase the cost or complexity of the exhaust system
144. A controller 148 controls operation of the engine system 100,
such as controlling the throttle valve 116 (airflow), the DI fuel
injectors 124 (fuel), and the spark plugs 128 (spark) and
communicates with a display 152 (e.g., a driver interface). The
controller 148 also receives the knock signal from the knock sensor
140. The controller 148 is configured to detect knock of the engine
104 by analyzing the knock signal. In one exemplary implementation,
the controller 148 is configured to detect both (i) LSPI knock and
(ii) spark knock using the knock signal, which will be described in
greater detail below. While not shown, it will be appreciated that
the controller 148 is configured to receive other inputs, such as a
crank angle measurement (e.g., in crank angle degrees, or CAD) from
a crankshaft position sensor (not shown).
[0022] Causes of LSPI knock events are numerous. Extended and
reoccurring LSPI can lead to thermal runways and surface (cylinder
wall) ignition. Possible causes of LSPI events include: (1) hot
combustion chamber deposits that flake off and ignite the cylinder
charge because the flaking deposit is exposed to long resonance
times and elevated pressure, which causes it to ignite, (2) oil
droplets from the piston crevice enter into the combustion chamber
of the cylinder 120 and act as a localized octane reducer causing
auto-ignition prior to the spark discharge, and (3) auto-ignition
prior to the spark discharge due to the boundary conditions, such
as in gasoline compression ignition engines. Some engines overcome
these surface ignition problems with improved hardware, engine
design, and calibration. LSPI events, however, are still
problematic in boosted engines with very retarded combustion
phasing and high compression ratios (long resonance times at
elevated pressure), particularly when operating at low speed and
high load.
[0023] In one exemplary implementation, the analyzing or processing
of the knock signal is as follows. For a particular monitoring
window, the knock signal is processed according to associated
parameters (signal amplifications, detection thresholds, etc.). In
one exemplary implementation, the knock signal is filtered,
rectified, and its energy is integrated across the monitoring
window to obtain a single value. The window could be calibrated
throughout the engine speed range. Based on a fast Fourier
transform (FFT), the "knocking frequency" is isolated, which allows
monitoring of first and second order pressure oscillations
occurring in a particular frequency range (e.g., 5-10 kilohertz
(kHz)). As previously discussed herein, only one monitoring window
is typically active at a time. Before a new window is active, there
may be a reset period for the controller 148. Thus, by implementing
two distinct monitoring windows separated by a controller reset
window, a single controller 148 is capable of detecting both LSPI
knock and spark knock using a single knock sensor 140.
[0024] Referring now to FIG. 2, a plot of an example LSPI knock
detection and mitigation process is illustrated. During normal
engine operation prior to time t.sub.1, the engine 104 is not
limited below its maximum output torque and is generating a nominal
torque T.sub.N. At time t.sub.1, an LSPI knock event is detected.
This represents the start of a first phase (Phase 1). It will be
appreciated that the term "LSPI knock event" could comprise a
plurality of detected occurrences of LSPI knock (e.g., a series of
consecutive LSPI knocks). In response to detecting the LSPI knock
event, the controller 148 limits the torque output of the engine
104 to a first torque limit T.sub.1 that is less than the nominal
torque T.sub.N. This reduction in torque output of the engine 104
could be achieved, for example, by controlling the throttle valve
116 and/or by controlling the wastegate or surge valve 126
associated with the boost system 122. This torque reduction is also
referred to herein as a "torque derate." For the initial detected
LSPI knock event, the controller 148 also enriches the fuel/air
ratio of the engine 104 (e.g., increases the amount of fuel
injected by the DI fuel injectors 128). As shown, this torque drop
to the first torque limit T.sub.1 occurs very fast as the process
is attempting to quickly mitigate the LSPI knock. The torque output
of the engine 104 is held at the first torque limit for a
calibratable period, such as a calibratable number of engine power
pulse (EPP) events (e.g., 30 EPP events).
[0025] After this calibratable period, the controller 148 removes
the limiting and increases engine torque output back to the nominal
torque T.sub.N. This represents the end of Phase 1. As shown,
however, another LSPI knock event is subsequently detected at time
t.sub.2. Thus, the fuel enrichment and temporary torque limiting
did not mitigate (or fully mitigate) the LSPI knock. This
represents the start of a second phase (Phase 2). The controller
148 again limits the torque output of the engine 104 for the
calibratable period (e.g., repeat a portion of Phase 1). After this
calibratable period, however, the controller 148 limits the torque
output of the engine to a second torque limit T.sub.2. As shown,
this second torque limit T.sub.2 is greater than the first torque
limit T.sub.1 but still less than the nominal torque T.sub.N. It
will be appreciated, however, that the second torque limit T.sub.2
could be the same as the first torque limit T.sub.1. This second
torque limit T.sub.2 is maintained by the controller 148 for the
remainder of a current key cycle of the engine 104 (e.g., until the
engine is turned off), after which Phase 2 ends. When a
calibratable number of entries into Phase 2 have occurred, a first
message could be output for the driver. Various exit conditions
also exist to effectively reset this Phase 2 counter. These are
discussed in greater detail below with reference to FIGS.
3A-3B.
[0026] As shown, before Phase 2 ends, yet another LSPI knock event
is detected at time t.sub.3 before the end of the current key cycle
of the engine 104. This represents the start of a third phase
(Phase 3). The controller 148 limits the torque output of the
engine 104 to a third torque limit T.sub.3 until a calibratable
amount of fuel has been consumed by the engine 104. This
calibratable amount of fuel could be one entire fuel tank of the
vehicle 100, but it will be appreciated that other suitable amounts
could be used. It will also be appreciated that fuel consumption
monitoring could continue across one or more partial fuel refill
events (e.g., Phase 3 would not end upon any single fuel refill
event). While the third torque limit T.sub.3 is shown as being less
than the first and second torque limits T.sub.1 and T.sub.2, it
will be appreciated that two or all of these torque limits T.sub.1,
T.sub.2, and T.sub.3 could have the same magnitudes. After the
calibratable amount of fuel has been consumed by the engine 104,
Phase 3 ends. When a calibratable number of entries into Phase 3
have occurred, a second message could be output to the driver.
Various exit conditions also exist to effectively reset this Phase
3 counter. These are discussed in greater now with reference to
FIGS. 3A-3B.
[0027] Referring now to FIGS. 3A-3B, flow diagrams of example LSPI
knock detection, mitigation, and driver notification methods 300,
380 are illustrated. Referring first to FIG. 3A, an example method
300 of knock detection, mitigation, and driver notification is
illustrated. At 304, the controller 148 detects whether an LSPI
event has occurred. When true, the method 300 proceeds to 304.
Otherwise, the method 300 ends or returns to 304. At 308, the
controller 148 increments an LSPI event counter. At 312, the
controller 148 determines whether the LSPI event detected at 304 is
the first LSPI event of a potential chain of events (e.g., whether
the LSPI event counter is equal to one). When true, the method 300
proceeds to 316 where fuel enrichment (enrichment of the FA ratio
of the engine 104) is performed by the controller 148. Otherwise,
the method 300 proceeds directly to 320. At 320, the controller 148
determines whether there are enough LSPI events to form a chain
(e.g., whether the LSPI event counter exceeds a calibratable event
threshold).
[0028] When true, the method 300 proceeds to 324. Otherwise, the
method 300 ends or returns to 304. At 324, the controller 148
increments an LSPI chain counter. At 328, the controller 148
performs short-term torque reduction. This could include, for
example, limiting torque to the first torque limit T.sub.1 for a
calibratable number of EPP events (see FIG. 2). At 332, the
controller 148 determines whether there are enough chains to derate
torque for the remainder of the current trip or key-cycle (e.g.,
whether the LSPI chain counter exceeds a calibratable chain
threshold). When true, the method 300 proceeds to 336. Otherwise,
the method 300 ends or returns to 304. At 336, the controller 148
increments a trip derate counter. At 340, the controller 148
performs key cycle torque reduction. This could include, for
example, limiting torque to the second torque limit T.sub.2 for the
remainder of the current key-cycle (see FIG. 2). At 344, the
controller 148 determines whether there are enough chains or
derated trips to derate torque for the remainder of the fuel tank
or some other calibratable amount of fuel (e.g., whether the
respective counters exceed respective calibratable tank
thresholds). When true, the method 300 proceeds to 348. Otherwise,
the method 300 ends or returns to 304.
[0029] At 348, the controller 148 increments a tank fail counter.
At 352, the controller 148 performs tank torque reduction. This
could include, for example, limiting torque to the third torque
limit T.sub.3 until the calibratable amount of fuel has been
consumed by the engine 104 (see FIG. 2). At 356, the controller 148
determines whether there are enough derated tanks or trip events to
output the second message instructing the driver to take the
vehicle to a service station for service (e.g., whether the
respective counters exceed calibratable service thresholds). When
true, the method 300 proceeds to 360 where the controller 148
outputs the second message (e.g., to display 152) and the method
300 then ends or returns to 304. Otherwise, the method 300 proceeds
to 364 where the controller outputs the first message (e.g., to
display 152) instructing the driver to provide a specific type or
quality of oil and or fuel to the vehicle 100 and the method 300
then ends or returns to 304.
[0030] Referring now to FIG. 3B, an example method 380 of
controlling the various counters described above is illustrated. At
382, the controller 148 determines whether a refuel event has
occurred. This could be determined, for example, using a fuel level
sensor in a fuel tank of the vehicle 100. When true, the method 380
proceeds to 384. Otherwise, the method 380 ends or returns to 382.
At 384, the controller 148 determines whether a tank derate is
currently active. When true, the method 380 proceeds to 386 where
the controller 148 clears or discontinues the tank derate and the
method 380 then ends or returns to 382. Otherwise, the method 380
proceeds to 388. At 388, the controller 148 determines whether the
tank fail counter is greater than zero. When true, the method 380
proceeds to 390. Otherwise, the method 380 ends or returns to 382.
At 390, the controller 148 increments a clear tank counter. At 392,
the controller 148 determines whether enough clear tanks (tank
refill events) have occurred to decrement the tank fail counter
(e.g., whether the number of clear tanks exceeds a calibratable
threshold). When true, the method 380 proceeds to 394. Otherwise,
the method 380 ends or returns to 382. At 394, the controller 148
decrements the tank fail counter. At 396, the controller 148 sets
the clear tank counter to zero and the method 380 then ends or
returns to 382. In other words, a certain number of clear tanks
(fuel refill events) without entering the tank derate can result in
the tank fail counter being decremented.
[0031] It will be appreciated that the term "controller" as used
herein refers to any suitable control device or set of multiple
control devices that is/are configured to perform at least a
portion of the techniques of the present disclosure. Non-limiting
examples include an application-specific integrated circuit (ASIC),
one or more processors and a non-transitory memory having
instructions stored thereon that, when executed by the one or more
processors, cause the controller to perform a set of operations
corresponding to at least a portion of the techniques of the
present disclosure. The one or more processors could be either a
single processor or two or more processors operating in a parallel
or distributed architecture.
[0032] It should be understood that the mixing and matching of
features, elements, methodologies and/or functions between various
examples may be expressly contemplated herein so that one skilled
in the art would appreciate from the present teachings that
features, elements and/or functions of one example may be
incorporated into another example as appropriate, unless described
otherwise above.
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