U.S. patent application number 10/431698 was filed with the patent office on 2004-11-11 for methods and apparatus for providing security for electronically-controlled cylinder activation and deactivation.
Invention is credited to Bauerle, Paul A., Costin, Mark H., Dibble, Donovan L., Katrak, Kerfegar K., Mehta, Vivek.
Application Number | 20040224819 10/431698 |
Document ID | / |
Family ID | 33159447 |
Filed Date | 2004-11-11 |
United States Patent
Application |
20040224819 |
Kind Code |
A1 |
Bauerle, Paul A. ; et
al. |
November 11, 2004 |
METHODS AND APPARATUS FOR PROVIDING SECURITY FOR
ELECTRONICALLY-CONTROLLED CYLINDER ACTIVATION AND DEACTIVATION
Abstract
Methods and apparatus are provided for ensuring that a throttle
increase accompanying a change in the number of active cylinders of
an internal combustion engine will not occur too long with more
than a selected fraction of all the cylinders activated, so as to
not startle a driver. The apparatus comprises an electronic
controller that generates the throttle increase if less than all
the cylinders are requested to be activated. A determination is
made as to whether the number of cylinders being fueled is equal to
or less than the selected fraction. A timer is started if the
number of cylinders being fueled is greater than the selected
fraction. The throttle increase is turned off if the amount of time
measured by the timer exceeds a threshold before the number of
cylinders being fueled becomes either less than or equal to the
selected fraction.
Inventors: |
Bauerle, Paul A.; (Fenton,
MI) ; Costin, Mark H.; (Bloomfield Township, MI)
; Dibble, Donovan L.; (Utica, MI) ; Katrak,
Kerfegar K.; (Fenton, MI) ; Mehta, Vivek;
(Bloomfield Hills, MI) |
Correspondence
Address: |
CHRISTOPHER DEVRIES
General Motors Corporation, Legal Staff
Mail Code 482-C23-B21
P.O. Box 300
Detroit
MI
48265-3000
US
|
Family ID: |
33159447 |
Appl. No.: |
10/431698 |
Filed: |
May 8, 2003 |
Current U.S.
Class: |
477/107 |
Current CPC
Class: |
F02D 2250/21 20130101;
F02D 11/105 20130101; F02D 2011/102 20130101; F02D 17/02 20130101;
F02D 41/0087 20130101; F02D 2041/0012 20130101; F02D 2041/002
20130101; F02D 2200/0404 20130101; F02D 41/123 20130101 |
Class at
Publication: |
477/107 |
International
Class: |
B60K 041/04 |
Claims
1. A security apparatus for an electronic fuel control system in an
engine of a vehicle, such apparatus comprising: a predetermined
number of cylinders of the engine that are configured for
activation and deactivation; a throttle of the engine that is
configured to provide a throttle increase based at least in part
upon a deactivation of one or more of said predetermined number of
cylinders; and an electronic controller that is configured to:
generate an increase signal for said throttle if less than all the
predetermined number of cylinders is requested to be activated;
determine whether a number of said predetermined number of
cylinders being activated is equal to or less than a selected
fraction; start timing with a timer if the number of said
predetermined number of cylinders being activated is greater than
the selected fraction; and request termination of said increase
signal if the time measured by the timer exceeds a predetermined
threshold.
2. The apparatus of claim 1 wherein the electronic fuel control
system further comprising: means for adjusting said throttle; and a
cylinder activation and deactivation system coupled to said means
for adjusting said throttle.
3. The apparatus of claim 2 being included in a mechanical system
having a transmission with a plurality of gears; said cylinder
activation and deactivation system being arranged to monitor which
of said plurality of gears is being employed by said transmission;
and said cylinder activation and deactivation system ensuring that
said increase request is generated only if said transmission is in
selected ones of said plurality of gears.
4. The apparatus of claim 1, wherein the selected fraction is
one-half.
5. The apparatus of claim 1, wherein the predetermined number of
cylinders is eight.
6. The apparatus of claim 1, wherein the predetermined number of
cylinders is twelve.
7. The apparatus of claim 1, wherein said predetermined threshold
can be calibrated.
8. The apparatus of claim 1, wherein said vehicle is an
automobile.
9. The apparatus of claim 1, wherein said engine is an internal
combustion engine.
10. A security method for an electronic fuel control system in an
engine of a vehicle having a predetermined number of cylinders, the
method comprising the steps of: generating an increase signal for a
throttle of the engine if less than all of the predetermined number
of cylinders is requested to be activated; determining whether a
number of the predetermined number of cylinders being activated is
equal to or less than the selected fraction; starting a timer if
the number of the predetermined number of cylinders being activated
is greater than the selected fraction; and requesting termination
of said increase signal if a time measured by said timer exceeds a
predetermined threshold.
11. The method of claim 10, further comprising the steps of:
monitoring which gear is being employed by a transmission having a
plurality of gears, said transmission being connected to the
engine; and providing the increase signal only if said transmission
is employing selected ones of said plurality of gears.
12. The method of claim 10, wherein said selected fraction is
one-half.
13. The method of claim 10, wherein the predetermined number of
cylinders is eight.
14. The method of claim 10, wherein said predetermined threshold
can be calibrated.
15. The method of claim 10, wherein said activation of said
predetermined number of cylinders comprises fueling.
16. The apparatus of claim 10, wherein the predetermined number of
cylinders is twelve.
17. The apparatus of claim 10, wherein said predetermined threshold
can be calibrated.
18. The apparatus of claim 10, wherein said vehicle is an
automobile.
19. The apparatus of claim 10, wherein said engine is an internal
combustion engine.
20. A security apparatus for an electronic fuel control system in
an internal combustion engine of an automobile, such security
apparatus comprising: eight cylinders of the engine that are
configured for activation and deactivation; a throttle of the
engine that is configured to provide a throttle increase based at
least in part upon a deactivation of one or more of the eight
cylinders; and an electronic controller that is configured to:
generate an increase signal for said throttle if less eight
cylinders are requested to be activated; determine whether the
number of eight cylinders being activated is equal to or less than
four; start timing with a timer if the number of eight cylinders
being activated is greater than four; and request termination of
said increase signal if the time measured by the timer exceeds a
predetermined threshold period.
Description
FIELD OF THE INVENTION
[0001] The present invention generally relates to electronic
throttle security, and more particularly relates to such security
for internal combustion engines having electronic throttle control
systems for enabling cylinder activation and deactivation.
BACKGROUND OF THE INVENTION
[0002] Those skilled in the art of internal combustion engine
design understand that control of internal combustion engines
preferably includes engine cylinder activation and deactivation or
displacement on demand to improve fuel economy. This engine control
strategy generally involves reducing the number of active engine
cylinders as a reduced amount of power is requested from the
engine, and the valves of deactivated cylinders are generally
configured to improve fuel efficiency. For example, the valves of
the deactivated cylinders are at least substantially closed to
reduce pumping losses. However, in this example, after some of the
cylinders are at least substantially closed to reduce pumping
losses, the remaining active cylinders are generally configured to
receive a throttle increase to maintain the same level of output
torque from the engine. Furthermore, when the power requirements
increase a sufficient amount, the deactivated cylinders are
reactivated and the throttle level is altered so that the engine
continues to deliver the desired amount of power.
[0003] It is desirable for the adjustments of the control strategy
to occur with minimal, and preferably no awareness of the engine
operator. This statement is particularly true in the case of an
automobile engine operating under the control of an operator that
is providing a substantially constant accelerator pedal position.
In this situation, the engine throttle is preferably adjusted a
predetermined amount in response to cylinder deactivation and
preferably adjusted a predetermined amount in response to cylinder
reactivation. While these control strategies for internal
combustion engines provide the proper engine power and improve fuel
efficiency, other improvements are continually sought.
[0004] In view of the foregoing, it should be appreciated that
there is a need to provide methods and apparatus for providing
security for electronically controlled cylinder activation and
deactivation. Furthermore, other desirable features and
characteristics of the present invention will become apparent from
the subsequent detailed description of the invention, brief summary
of the invention, abstract, and appended claims, taken in
conjunction with the accompanying drawings and this background of
the invention of the invention.
BRIEF SUMMARY OF THE INVENTION
[0005] In accordance with the teachings of the present invention
security methods and apparatus are provided for ensuring that a
throttle increase accompanying a decrease in the number of active
cylinders of an internal combustion engine will be limited to a
predetermined threshold period with more than a selected fraction
of all the cylinders of the engine being activated. The apparatus
comprises an electronic controller that generates the throttle
increase if less than all the cylinders are requested to be
activated. A query is made to determine if the number of cylinders
being fueled is equal to or less than the selected fraction. A
timer is started if the number of cylinders being fueled is greater
than the selected fraction of all the cylinders. The throttle
increase is turned off if the amount of time measured by the timer
exceeds the predetermined threshold before the number of cylinders
being fueled becomes either less than or equal to the selected
fraction.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] The present invention will hereinafter be described in
conjunction with the appended drawing figures, wherein like
reference numbers denote like elements, and
[0007] FIG. 1 is a schematic diagram of a vehicle drive train
having a security system for cylinder deactivation and
reactivation;
[0008] FIG. 2 is a flow chart of a software program for use with
the system of FIG. 1 in accordance with an embodiment of the
invention;
[0009] FIG. 3 is a timing diagram indicating a normal mode of
operation of the security system of FIGS. 1 and 2; and
[0010] FIG. 4 is a timing diagram indicating a fault mode of
operation of the security system of FIGS. 1 and 2.
DETAILED DESCRIPTION OF THE INVENTION
[0011] The following detailed description is merely exemplary in
nature and is not intended to limit the invention or the
application and uses of the invention. Furthermore, there is no
intention to be bound by any theory presented in the preceding
background of the invention or the following detailed
description.
[0012] Referring to FIG. 1, a vehicle drive train 10 is generally
illustrated that includes an internal combustion engine 12 coupled
to transmission 14, which in turn is coupled by drive shaft 16 and
differential 18 to a pair of driven wheels 20a-20b. The position of
a throttle 22 disposed within a manifold 21 of engine 12 is
controlled to enable engine 12 to produce the desired output torque
for driving wheels 20a-20b. In the illustrated embodiment, throttle
22 is mechanically de-coupled from driver accelerator pedal 23 and
instead is positioned by electric motor 24 under the direction of
powertrain control module (PCM) 26 that also controls the operation
of engine 12 and transmission 14. PCM 26 includes electronic
throttle control (ETC) 27 for operating throttle 22. ETC 27
provides signals to motor 24. PCM 26 is microprocessor based and
includes various logic units and memories such as ROM and RAM.
[0013] PCM 26 operates in response to a number of inputs. These
inputs include an engine speed signal (Ne) on line 28, a vehicle
speed signal (Nv) on line 30, an accessory loading signal (ACC) on
line 34, a Throttle Position Feedback signal (TPS) on line 36, a
Manifold Absolute Pressure (MAP) signal on line 38 and Pedal
Position Sensor signal (PPS) on line 39. These inputs are provided
by conventional sensors such as illustrated shaft speed sensors 40,
42 and accelerator pedal position sensor 44. In general, ETC module
27 activates motor 24 to position throttle 22 in response to the
positioning of accelerator pedal 23, but various other functions
such as idle speed control, engine governor control, cruise control
and torque reduction are also provided for providing the ETC
function in a known manner. Additionally, PCM 26 controls
conventional spark control device 50 and other fuel control device
52, which are coupled to engine 12.
[0014] More specifically, internal combustion engine 12 utilizes
the PCM/ETC functions provided by system 26 to adjust the fuel, the
spark and the amount of airflow through intake manifold 21 in
response to sensor monitored operator variations of accelerator
pedal 23. Operator throttle adjustment is typically accomplished
using an accelerator-input mechanism, such as a foot pedal 23,
joystick, hand pedal, lever or track ball. The input mechanism is
mechanically coupled to sensors in block 44 that in turn provide
PPS control signals having magnitudes indicative of the accelerator
position to the ETC module 27. In response, PCM 26 generates
additional electrical control signals for enabling the hardware of
the vehicle engine to provide the desired operating level requested
by the driver as indicated by the accelerator-input mechanism 23.
Such ETC systems provide numerous advantages such as reduced costs,
improved simplicity, engine noise reduction, throttle command
conditioning for emissions reduction, and/or torque based control
functions.
[0015] DEAC system 54 provides cylinder activation, deactivation
and reactivation to improve a number of operating parameters, such
as fuel economy. This is generally accomplished by shutting off or
deactivating a predetermined number of the cylinders of engine 12
when the power requirements of the engine are at or below a
predetermined lower power level (i.e., the power level is too low)
and reactivating the cylinders when the power requirements
sufficiently are at or exceed a predetermined upper power level. As
can be appreciated by those of ordinary skill in the art, the
predetermined power levels can be determined according to any
number of techniques. Ideally, the operator of engine 12 or driver
of a vehicle including engine 12 is not aware of these transitions.
Engine 12 has a predetermined number of cylinders and a selected
fraction of this number is operated when deactivation reaches a
steady state. For instance, if engine 12 has eight cylinders, which
is a well known V8 configuration, and the fraction is one half,
then engine 12 could be operated on all eight cylinders when the
need for power is high (i.e., the power level is at or exceeds the
predetermined upper power level). In addition, the engine 12 could
transition to eventually operate on only four cylinders when the
need for power is sufficiently low (i.e., at or below the
predetermined low level). Engine 12 could also have twelve
cylinders. In this case, engine 12 could run on eight, six or four
cylinders depending on the power demand requirements, for instance.
In any event, the valves of any deactivated cylinders are at least
partially closed and preferably completely closed.
[0016] DEAC system 54 is coupled to monitor engine 12 and
transmission 14 through respective lines 56 and 57 to enable DEAC
54 to provide control signals to PCM 26 through line 58. When some
of the cylinders of engine 12 are shut off, the other active
cylinders of the engine are run in response to a higher opening of
throttle 22 referred to herein as THROTTLE OFFSET. This action
maintains substantially the same level of output torque being
delivered through transmission 14 and differential 18 to wheels 20a
and 20b. It is desirable for the larger opening of throttle 22 to
occur with minimal and preferably, no action or even awareness by
the operator of the engine of the cylinder deactivation event. In
addition, it is desirable for the operator to have minimal
awareness of cylinder reactivations. To ensure a seamless
transition, throttle 22 should be opened at a time slightly before
the cylinders are in a deactivated mode. The system preferably
avoids the opening of throttle 22 to provide the THROTTLE OFFSET
without verification that fuel is shut off to at least some of the
cylinders.
[0017] Engine 12 could have any number of cylinders greater than
one. For purposes of illustration, engine 12 is assumed the
aforementioned V8, which is operated on four cylinders when
conditions are correct for cylinder deactivation. DEAC 54 provides
the THROTTLE OFFSET during the time the cylinder deactivation logic
is requesting the throttle to be opened, but the THROTTLE OFFSET is
allowed to continue if half or less of the fuel injectors are
disabled before a predetermined threshold period (or time limit
threshold) is met or exceeded.
[0018] Referring to FIG. 2, a method 60 is illustrated that is
preferably conducted by the PCM 26. However, the method can be
conducted by other electronic controllers, individually or in
combination. The timing diagrams 62 and 64 respectively of FIG. 3
and FIG. 4 illustrate the operation of apparatus 10 of FIG. 1 and
method 60 of FIG. 2 Abscissa axis 66 of FIG. 3 is the time between
times T0 and T18. Time, T0 on axis 66 corresponds to BEGIN step 68
of method 60.
[0019] DEAC MODE REQUEST graph 70 of FIG. 3 is initially assumed to
be requesting that all eight cylinders receive fuel as indicated by
level 72. Accordingly, eight cylinders are being fueled between
times T0 and T1 as indicated by level 74 of graph 76 which
indicates the NUMBER OF CYLINDERS BEING FUELED. Decision block or
method step 78 of FIG. 2 determines if DEAC 54 is requesting
activation of less than all the cylinders. Since the answer is NO
between T0 and T1, the TIMER is RESET as indicated by block 85.
Accordingly, OFFSET FUEL ON FLAG 86 is FALSE as indicated by block
86 of FIG. 2 and level 88 of OFFSET FUEL ON FLAG waveform 90 of
FIG. 3. OR block 92 of FIG. 2 responds to FALSE level 88 to ensure
that the THROTTLE OFFSET is OFF per block 94 to provide level 96 of
THROTTLE OFFSET waveform 98 of FIG. 3. Hence, engine 12 does not
receive the THROTTLE OFFSET fuel increase between T0 and T1.
[0020] Referring to FIG. 1, DEAC 54 receives input on line 57
identifying which gear is being employed in transmission 14.
Deactivation of any of the cylinders is not desirable if
transmission 14 is in a predetermined lower gear or a predetermined
set of lower gears (i.e., the gear or gears is too low), such as
either the first or the second gear, for instance. If the gear is
too low for cylinder deactivation to be desirable, then the NO
decision from block 100 of FIG. 2 causes block 102 to provide a
GEAR STATE ENABLE FLAG having a FALSE indication to OR block 92.
This causes the THROTTLE OFFSET request to be OFF as indicated by
block 94. Alternatively, if the gear is a gear other than the
predetermined lower gear or gears, then the YES from decision block
100 causes the GEAR STATE ENABLE FLAG to be TRUE as indicated by
block 104 of FIG. 2. For purposes of the following discussion
herein, it is assumed that the gear level is correct for
deactivation resulting in the TRUE GEAR STATE ENABLE FLAG of block
104.
[0021] At time T1 of FIG. 3, DEAC 54 requests deactivation of half
of the predetermined maximum number of cylinders as indicated by
level 105 of waveform 70. The number of cylinders being fueled then
transitions from eight to seven as indicated by level 106 of
waveform 76 of FIG. 3. Accordingly, decision step 78 of FIG. 2 now
provides a YES. As a result, the OFFSET FUEL ON FLAG is TRUE as
indicated by block 108 and level 109 of waveform 90. AND block 112
responds to the TRUE from block 108 and the TRUE from block 104 to
provide the THROTTLE OFFSET ON SIGNAL of block 113 as indicated by
level 114 of waveform 98 of FIG. 3. Level 114 results in an
increased amount of fuel being supplied to the active
cylinders.
[0022] THROTTLE OFFSET ON signal 114 of block 113 of FIG. 2
initiates the decision step of block 115 which determines if the
number of fueled cylinders is less than or equal to one half the
number of all the cylinders, for instance. Since seven, six and
five as indicated by respective levels 106, 116 and 117 of waveform
76 of FIG. 3 are all greater than four the answer to decision 115
is NO between times T1 and T4. Accordingly, the START TIMER signal
of block 118 causes OFFSET FUEL OFF TIMER waveform 119 to ramp from
reset level 120 to begin measuring time from T1 as indicated by
ramp 121 of waveform 119.
[0023] At time T4, the number of cylinders being fueled equals four
as indicated by level 125 of waveform 76. Accordingly, the decision
from block 115 becomes YES which RESETS the TIMER as indicated by
block 126 of FIG. 2 to cause transition 128 of waveform 119 back to
reset level 120. The amount of time from T1 to T4 is less than a
predetermined or selected THRESHOLD amount of time (i.e., the
predetermined threshold period), T5. Hence, the answer of decision
block 130 is NO which allows the OFFSET FUEL ON FLAG to continue to
be TRUE as indicated by block 108. The above sequence of events
represents the "normal case" for the operation of the DEAC
function. The THRESHOLD time, T5 may be calibrated or changed in
response to monitored parameters.
[0024] At time T6 of FIG. 3, DEAC MODE signal 70 changes to and
remains at level 130 to facilitate operation in the steady state
four cylinder active condition until time T10 when signal 70 moves
to level 132 to indicate a request for reactivation of an
additional cylinder. Since activation of all cylinders is not being
requested at T10, decision block 78 provides a YES so that the
OFFSET FUEL ON FLAG continues to be TRUE resulting in THROTTLE
OFFSET signal 98 remaining at level 114. Five cylinders are being
fueled between T10 and T11 as indicated by level 134 of waveform
76. Accordingly, at T10 decision block 115 provides a NO which
again provides the START TIMER signal of block 118 and waveform 119
begins ramp 136. Six, seven and eight cylinders are respectively
reactivated at T11, T12 and T13 as indicated by respective levels
138, 140 and 142 of waveform 76.
[0025] At T14, the system returns to the reactivated eight-cylinder
mode as indicated by level 143 of DEAC signal 70. As a result,
decision block 78 becomes NO which causes the TIMER to RESET to
level 120 of waveform 119 per block 85. The NO from block 78 also
initiates the FALSE OFFSET FUEL ON FLAG of block 86 which causes
waveform 90 to return to level 88. Accordingly, the THROTTLE OFFSET
OFF signal of block 94 causes signal the THROTTLE OFFSET 98 to
return to level 96. Such reactivation occurs is another "normal
case" of operation for the DEAC function.
[0026] FIG. 4 illustrates a "fault case" for the DEAC function
which employs the previously mentioned security method and
apparatus. Between T0 and T3, the waveforms of FIG. 4 are the same
as in FIG. 3 indicating the same method as previously described for
FIG. 2. However, at T3 waveform 76 representing the number of
cylinders being fueled undesirably remains at six cylinders as
indicated by level 116 rather than dropping to five cylinders.
Accordingly, system 10 is now operating in the abnormal or fault
mode. Since the NUMBER OF FUELED CYLINDERS does not become equal to
or less than four, TIMER RESET 126 of FIG. 2 is not enabled by
decision block 115. Thus, OFFSET FUEL OFF TIMER waveform 119
portion 150 of FIG. 4 continues to ramp through the time THRESHOLD
T5. As a result, decision block 130 provides a YES which enables
the FALSE FUEL ON ENABLE FLAG of block 86 which causes signal 90 to
drop to level 88 at T5. As a result, the THROTTLE OFFSET 98 returns
to level 96 at T5 to remove the extra fuel being applied to the
activated cylinders of engine 112.
[0027] Furthermore, referring again to FIG. 3, if only seven
cylinders are reactivated during the reactivation sequence, then
ramp 136 of waveform 119 would continue on to form dashed portion
152 which would cross time THRESHOLD T15. This event also would
result in a YES from decision block 130 causing the OFFSET FUEL ON
FLAG to become FALSE and the THROTTLE OFFSET also becoming FALSE.
Hence, the extra fuel would again be terminated.
[0028] The previously described embodiments of the invention
therefore provide a security apparatus and method which ensure that
the higher THROTTLE OFFSET fuel level 114 will not be used for a
long enough time with more than a selected fraction of the
predetermined maximum number of cylinders. For instance, the
invention provides security to ensure that THROTTLE OFFSET 98 is
not allowed to remain on at level 114 long enough with more than
half of the cylinders enabled.
[0029] While the exemplary embodiments have been presented in the
foregoing detailed description, it should be appreciated that a
vast number of variations exist. It should also be appreciated that
these exemplary embodiments are only examples, and are not intended
to limit the scope, applicability, or configuration of the
invention in any way. Rather, the foregoing detailed description
will provide those skilled in the art with a convenient road map
for implementing an exemplary embodiment of the invention, it being
understood that various changes may be made in the function and
arrangement of elements described in an exemplary embodiment
without departing from the spirit and scope of the invention as set
forth in the appended claims.
* * * * *