U.S. patent application number 16/241179 was filed with the patent office on 2019-05-09 for method to optimize engine operation using active fuel management.
The applicant listed for this patent is GM Global Technology Operations LLC. Invention is credited to Andrew J. Harkenrider, Nigel K. Hyatt, Chad D. Kromrey, Zhong Li.
Application Number | 20190135287 16/241179 |
Document ID | / |
Family ID | 61166643 |
Filed Date | 2019-05-09 |
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United States Patent
Application |
20190135287 |
Kind Code |
A1 |
Kromrey; Chad D. ; et
al. |
May 9, 2019 |
METHOD TO OPTIMIZE ENGINE OPERATION USING ACTIVE FUEL
MANAGEMENT
Abstract
A method for operating an internal combustion engine comprises
providing a vehicle having an internal combustion gasoline engine
including multiple cylinders and wherein the engine is operating in
a deactivated cylinder mode, receiving a torque request if a
cylinder reactivation torque smoothing mode is active, setting a
variable torque ratio to 1.0 if the torque request is greater than
a fast exit threshold torque, setting the variable torque ratio to
0.0 if the torque request is less than a slow exit threshold
torque, setting the variable torque ratio to a value between 0.0
and 1.0 if the torque request is between the fast exit threshold
torque and slow exit threshold torque, and calculating a component
of final engine output torque.
Inventors: |
Kromrey; Chad D.; (Perry,
MI) ; Li; Zhong; (Novi, MI) ; Hyatt; Nigel
K.; (West Bloomfield, MI) ; Harkenrider; Andrew
J.; (Oakland Township, MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
GM Global Technology Operations LLC |
Detroit |
MI |
US |
|
|
Family ID: |
61166643 |
Appl. No.: |
16/241179 |
Filed: |
January 7, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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15251645 |
Aug 30, 2016 |
10183672 |
|
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16241179 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F02D 41/3005 20130101;
B60W 10/06 20130101; B60W 2710/0666 20130101; B60W 2510/0609
20130101; B60W 2510/0604 20130101; F02D 41/10 20130101; F02D
41/0087 20130101; B60W 2540/106 20130101; F02D 2250/21 20130101;
B60W 10/10 20130101; F02D 17/02 20130101; F02D 2250/18 20130101;
B60W 2710/0672 20130101; F02D 41/0002 20130101; B60W 2710/0622
20130101; B60W 2540/10 20130101; B60W 2710/0644 20130101; B60W
2510/0657 20130101; B60W 30/1882 20130101 |
International
Class: |
B60W 30/188 20060101
B60W030/188; B60W 10/06 20060101 B60W010/06; F02D 41/10 20060101
F02D041/10; F02D 17/02 20060101 F02D017/02; B60W 10/10 20060101
B60W010/10; F02D 41/00 20060101 F02D041/00; F02D 41/30 20060101
F02D041/30 |
Claims
1. A method for operating an internal combustion engine, the method
comprising: providing a vehicle having an internal combustion
gasoline engine including multiple cylinders and wherein the engine
is operating in a deactivated cylinder mode; receiving a torque
request if a cylinder reactivation torque smoothing mode is active;
setting a variable torque ratio to r.sub.max if the torque request
is greater than a fast exit threshold torque, and setting the
variable torque ratio to a value less than r.sub.max if the torque
request is less than the fast exit threshold torque.
2. The method of operating an internal combustion engine of claim 1
further comprising calculating a component of final engine output
torque using the variable torque ratio.
3. The method of operating an internal combustion engine of claim 2
wherein calculating the component of final engine output torque
t.sub.f further comprises calculating the component of final engine
output torque according to the formula: t.sub.f=r(t.sub.fast), and
wherein t.sub.fast is the fast exit threshold torque and r is the
variable torque ratio.
4. The method of operating an internal combustion engine of claim 1
wherein setting the variable torque ratio to a value below
r.sub.max if the torque request is below the fast exit threshold
torque further comprises setting the variable torque ratio to a
value proportional to the torque request if the torque request is
below the fast exit threshold torque.
5. The method of operating an internal combustion engine of claim 1
wherein setting the variable torque ratio to r.sub.max if the
torque request is greater than a fast exit threshold torque further
comprises setting the variable torque ratio r to 1.0 if the torque
request is greater than the fast exit threshold torque.
6. A method for operating an internal combustion engine, the method
comprising: providing a vehicle having an internal combustion
gasoline engine including multiple cylinders and wherein the engine
is operating in a deactivated cylinder mode; receiving a torque
request if a cylinder reactivation torque smoothing mode is active;
setting a variable torque ratio to r.sub.min if the torque request
is less than a slow exit threshold torque, and setting the variable
torque ratio to a value greater than r.sub.min if the torque
request is greater than the slow exit threshold torque.
7. The method of operating an internal combustion engine of claim 6
further comprising calculating a component of final engine output
torque using the variable torque ratio.
8. The method of operating an internal combustion engine of claim 7
wherein calculating the component of final engine output torque
t.sub.f further comprises calculating the component of final engine
output torque according to the formula: t.sub.f=r(t.sub.slow), and
wherein t.sub.slow is the slow exit threshold torque and r is the
variable torque ratio.
9. The method of operating an internal combustion engine of claim 6
wherein setting the variable torque ratio to a value greater than
r.sub.min if the torque request is greater than the slow exit
threshold torque further comprises setting the variable torque
ratio to a value proportional to the torque request if the torque
request is greater than the slow exit threshold torque.
10. The method of operating an internal combustion engine of claim
6 wherein setting the variable torque ratio to r.sub.min if the
torque request is less than a slow exit threshold torque further
comprises setting the variable torque ratio to 0.0 if the torque
request is less than the slow exit threshold torque.
11. A method for operating an internal combustion engine, the
method comprising: providing a vehicle having an internal
combustion gasoline engine including multiple cylinders and wherein
the engine is operating in a deactivated cylinder mode; receiving a
torque request if a cylinder reactivation torque smoothing mode is
active; setting a variable torque ratio to r.sub.max if the torque
request is greater than a fast exit threshold torque, and setting
the variable torque ratio to a value less than r.sub.max if the
torque request is less than the fast exit threshold torque.
12. The method of operating an internal combustion engine of claim
11 further comprising setting the variable torque ratio to
r.sub.min if the torque request is less than a slow exit threshold
torque.
13. The method of operating an internal combustion engine of claim
12 further comprising setting the variable torque ratio to a value
between r.sub.min and r.sub.max if the torque request is between
the fast exit threshold torque and the slow exit threshold
torque.
14. The method of operating an internal combustion engine of claim
13 further comprising calculating a component of final engine
output torque using the variable torque ratio.
15. The method of operating an internal combustion engine of claim
14 wherein calculating the component of final engine output torque
t.sub.f further comprises calculating the component of final engine
output torque according to the formula:
t.sub.f=t.sub.slow+r(t.sub.fast-t.sub.slow), and wherein t.sub.fast
is the fast exit threshold torque, t.sub.slow is the slow exit
threshold torque, and r is the variable torque ratio.
16. The method of operating an internal combustion engine of claim
15 wherein setting the variable torque ratio to a value between
r.sub.min and r.sub.max if the torque request is between the fast
exit threshold torque and the slow exit threshold torque further
comprises setting the variable torque ratio to a value proportional
to the torque request if the torque request is between the fast
exit threshold torque and the slow exit threshold torque.
17. The method of operating an internal combustion engine of claim
16 wherein setting the variable torque ratio to r.sub.max if the
torque request is greater than a fast exit threshold torque further
comprises setting the variable torque ratio to 1.0 if the torque
request is greater than the fast exit threshold torque.
18. The method of operating an internal combustion engine of claim
17 wherein setting the variable torque ratio to r.sub.min if the
torque request is less than a slow exit threshold torque further
comprises setting the variable torque ratio to 0.0 if the torque
request is less than the slow exit threshold torque.
19. The method of operating an internal combustion engine of claim
18 wherein setting the variable torque ratio to r.sub.max if the
torque request is greater than a fast exit threshold torque further
comprises setting the variable torque ratio to r.sub.max if the
torque request is greater than the fast exit threshold torque
wherein the fast exit threshold torque is derived from calibration
tables having a fast exit threshold torque value for one of a
plurality of operational parameters.
20. The method of operating an internal combustion engine of claim
19 wherein setting the variable torque ratio to r.sub.min if the
torque request is less than a slow exit threshold torque further
comprises setting the variable torque ratio to r.sub.min if the
torque request is less than the slow exit threshold torque wherein
the slow exit threshold torque is derived from calibration tables
having a slow exit threshold torque value for one of a plurality of
operational parameters.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. patent
application Ser. No. 15/251,645 filed on Aug. 30, 2016. The
disclosure of the above application is incorporated herein by
reference.
INTRODUCTION
[0002] The disclosure relates generally to automobile engine
control and more particularly to operation of an internal
combustion engine while the engine is being run in an active fuel
management mode for optimization of fuel efficiency.
[0003] A typical internal combustion engine is a combination of
systems that individually serve a specific function. The air intake
system provides throttled air to the engine. The fuels system
stores, transports, and regulates fuel flow into the combustion
chambers of the engine. The ignition system provides spark for
igniting the air/fuel mixture. The power conversion system converts
the chemical energy of combustion into work that is transferred to
the tires of the vehicle. Other systems perform functions that
improve fuel economy and emissions, cool the engine and provide
heat to the vehicle cabin, or run other accessories such as power
steering or air conditioning.
[0004] The size of the engine is typically tailored to the size and
purpose of the vehicle. For example, a small light car built for
fuel efficiency may include a small three cylinder or four cylinder
engine having 1.5 to 2.0 Liters of displacement. Alternatively, a
full-size pick-up truck or van that is purposely built for carrying
tools and pulling machinery will require an engine having a larger
displacement and more cylinders. A displacement of 4.5 L and above
in a V8 or V10 configuration provides the torque and power required
to carry and pull heavy loads. However, there are occasions of use
when such a vehicle will not require all of the torque available in
the V8 or V10 engine. It is during such occasions that it becomes
desirable from a fuel efficiency standpoint to simply not use all
of the cylinders that are available. Thus, a method of operating
the engine has been developed to improve fuel economy while
maintaining the overall capacity of torque available to the vehicle
operator.
[0005] Active fuel management methods have been developed which
include shutting off fuel delivery to a cylinder when the torque
demand on the engine is low. However, there are many issues with
controlling an engine and powertrain when using active fuel
management. Drivability, torque demand, Noise and Vibration must
all be maintained or improved while at the same time improving fuel
economy. Thus, while current active fuel management controls
achieve their intended purpose, the need for new and improved
active fuel management controls which ensure the vehicle operators
expectations are achieved is essentially constant. Accordingly,
there is a need for an improved and reliable active fuel management
controls system and method.
SUMMARY
[0006] An internal combustion engine control method is provided,
the method includes providing a vehicle having an internal
combustion gasoline engine including multiple cylinders and wherein
the engine is operating in a deactivated cylinder mode, receiving a
torque request if a cylinder reactivation torque smoothing mode is
active, setting a variable torque ratio to r.sub.max if the torque
request is greater than a fast exit threshold torque t.sub.fast,
setting the variable torque ratio to r.sub.min if the torque
request is less than a slow exit threshold torque t.sub.slow,
setting the variable torque ratio to a value between r.sub.max and
r.sub.min if the torque request is between the fast exit threshold
torque and slow exit threshold torque, and calculating a final
engine output torque.
[0007] In one example of the present disclosure, calculating a
final engine output torque further comprises calculating a final
engine output torque according to the formula:
t.sub.f=t.sub.slow+r(t.sub.fast-t.sub.slow), and
wherein t.sub.fast is the fast exit threshold torque, t.sub.slow is
the slow exit threshold torque, and r is the variable torque
ratio.
[0008] In another example of the present disclosure, setting the
variable torque ratio to a value between r.sub.min and r.sub.max if
the torque request is between the fast exit threshold torque
t.sub.fast and slow exit threshold torque t.sub.slow further
comprises setting the variable torque ratio to a value proportional
to the torque request if the torque request is between the fast
exit threshold torque t.sub.fast and slow exit threshold torque
t.sub.slow.
[0009] In yet another example of the present disclosure, setting a
variable torque ratio to r.sub.max if the torque request is greater
than a fast exit threshold torque t.sub.fast further comprises
setting a variable torque ratio to 1.0 if the torque request is
greater than a fast exit threshold torque.
[0010] In yet another example of the present disclosure, setting
the variable torque ratio to r.sub.min if the torque request is
less than a slow exit threshold torque t.sub.slow further comprises
setting the variable torque ratio to 0.0 if the torque request is
less than a slow exit threshold torque.
[0011] In yet another example of the present disclosure, setting a
variable torque ratio to r.sub.max if the torque request is greater
than a fast exit threshold torque t.sub.fast further comprises
setting the variable torque ratio to r.sub.max if the torque
request is greater than the fast exit threshold torque t.sub.fast
wherein the fast exit threshold torque t.sub.fast is derived from
calibration tables having a fast exit threshold torque t.sub.fast
value for a plurality of operational parameters.
[0012] In yet another example of the present disclosure, setting a
variable torque ratio to r.sub.min if the torque request is less
than a slow exit threshold torque t.sub.slow further comprises
setting the variable torque ratio to r.sub.min if the torque
request is less than the slow exit threshold torque t.sub.slow
wherein the slow exit threshold torque t.sub.slow is derived from
calibration tables having a slow exit threshold torque t.sub.slow
value for a plurality of operational parameters.
[0013] Another internal combustion engine control method is
provided, the method includes providing a vehicle having an
internal combustion gasoline engine including multiple cylinders
and wherein the engine is operating in a deactivated cylinder mode,
receiving a torque request if a cylinder reactivation torque
smoothing mode is active, setting a variable torque ratio to
r.sub.max if the torque request is greater than a fast exit
threshold torque, and setting the variable torque ratio to a value
less than r.sub.max if the torque request is less than the fast
exit threshold torque.
[0014] In one example of the present disclosure, the method further
comprises calculating a component of final engine output torque
using the variable torque ratio.
[0015] In another example of the present disclosure, calculating
the component of final engine output torque t.sub.f further
comprises calculating the component of final engine output torque
according to the formula:
t.sub.f=r(t.sub.fast), and
wherein t.sub.fast is the fast exit threshold torque and r is the
variable torque ratio.
[0016] In yet another example of the present disclosure, setting
the variable torque ratio to a value below r.sub.max if the torque
request is below the fast exit threshold torque further comprises
setting the variable torque ratio to a value proportional to the
torque request if the torque request is below the fast exit
threshold torque.
[0017] In yet another example of the present disclosure, setting
the variable torque ratio to r.sub.max if the torque request is
greater than a fast exit threshold torque further comprises setting
the variable torque ratio r to 1.0 if the torque request is greater
than the fast exit threshold torque.
[0018] Another internal combustion engine control method is
provided. The method includes providing a vehicle having an
internal combustion gasoline engine including multiple cylinders
and wherein the engine is operating in a deactivated cylinder mode,
receiving a torque request if a cylinder reactivation torque
smoothing mode is active, setting a variable torque ratio to
r.sub.min if the torque request is less than a slow exit threshold
torque, and setting the variable torque ratio to a value greater
than r.sub.min if the torque request is greater than the slow exit
threshold torque.
[0019] In one example of the present disclosure, the method further
comprises calculating a component of final engine output torque
using the variable torque ratio.
[0020] In another example of the present disclosure, calculating
the component of final engine output torque t.sub.f further
comprises calculating the component of final engine output torque
according to the formula:
t.sub.f=r(t.sub.slow), and
wherein t.sub.slow is the slow exit threshold torque and r is the
variable torque ratio.
[0021] In yet another example of the present disclosure, setting
the variable torque ratio to a value greater than r.sub.min if the
torque request is greater than the slow exit threshold torque
further comprises setting the variable torque ratio to a value
proportional to the torque request if the torque request is greater
than the slow exit threshold torque.
[0022] In yet another example of the present disclosure, setting
the variable torque ratio to r.sub.min if the torque request is
less than a slow exit threshold torque further comprises setting
the variable torque ratio to 0.0 if the torque request is less than
the slow exit threshold torque.
[0023] The above features and advantages and other features and
advantages of the present disclosure are readily apparent from the
following detailed description when taken in connection with the
accompanying drawings.
DRAWINGS
[0024] The drawings described herein are for illustration purposes
only and are not intended to limit the scope of the present
disclosure in any way.
[0025] FIG. 1 is a depiction of a powertrain of a vehicle in
accordance with an example of the present disclosure;
[0026] FIG. 2 is a top view schematic of an internal combustion
engine, in accordance with an example of the present
disclosure;
[0027] FIG. 3 is a side view schematic of an internal combustion
engine, in accordance with an example of the present
disclosure;
[0028] FIG. 4 is a schematic depicting a method of controlling an
engine of a vehicle, in accordance with an example of the present
disclosure; and
[0029] FIG. 5 is a flow chart depicting a method of controlling an
engine of a vehicle, in accordance with an example of the present
disclosure.
DETAILED DESCRIPTION
[0030] The following description is merely exemplary in nature and
is not intended to limit the present disclosure, application, or
uses.
[0031] With reference to FIG. 1, an exemplary powertrain is
generally indicated by reference number 10. The powertrain 10
includes an engine 12, a transmission 14, a driveshaft and rear
differential 16, drive wheels 18, and a powertrain control module
20. The engine 12 is an internal combustion engine that supplies a
driving torque to the transmission 14. Traditionally, an internal
combustion engine is identified by the number of cylinders it
includes and in what configuration the cylinders are arranged. The
engine 12 shown is a V8 configured engine 12 as the engine 12
includes eight cylinders arranged in a "V" configuration. The
transmission 14, capable of several forward gear ratios, in turn
delivers torque to the driveshaft and rear differential 16 and
drive wheels 18.
[0032] Turning now to FIGS. 2 and 3, the engine 12 is illustrated
and described in greater detail. The engine 12 as a system is a
combination of multiple sub-systems operating in a coordinated
manner managed by the powertrain control module 20 to convert
combustion into mechanical work. For example, the engine 12 may
include a fuel delivery system 22, an ignition system 24, an air
intake system 26, a power conversion system 28, an exhaust system
30, and a valvetrain system 32, among other subsystems. More
particularly, the power conversion system 28 includes a plurality
of pistons 34, connecting rods 36, cylinders 38, and a crankshaft
40. Each piston 34 is disposed in one of the cylinders 38 with the
piston 34 pinned to an end of a connecting rod 36 with the other
end of the connecting rod 36 pinned to an offset journal of the
crankshaft 40. The top side of the piston 34 and the cylinder 38
form a combustion chamber 42. The crankshaft 40 is connected on one
end to an output member (not shown) for transferring torque to the
transmission 14.
[0033] The air intake system 26 includes a plurality of air ducts
44 and a throttle valve 46. The throttle valve 46 controls the
amount of airflow passing into the air intake system 26 while the
air ducts 44 direct incoming air to be used in the combustion
process into the combustion chamber 42.
[0034] The valvetrain system 32 includes an intake valve 48 and an
exhaust valve 50 in each cylinder 38 and a mechanism (not shown)
for actuating the intake valve 48 and exhaust valve 50. The intake
valve 48 opens to allow communication between the air ducts 44 of
the air intake system 26 and the combustion chamber 42. In the
present example, there is only one intake valve 48 and one exhaust
valve 50 in each combustion chamber 42. However, a valvetrain
system 32 having more than one intake valve 48 or exhaust valve 50
in each cylinder 38 may be considered without departing from the
scope of the present disclosure.
[0035] The fuel delivery system 22 includes a pressurized fuel
source or fuel pump 52, fuel lines 54, and fuel injectors 56. The
fuel pump 52 is disposed in the fuel tank (not shown) located
elsewhere in the vehicle. The fuel pump 52 pressurizes the fuel
lines 54 which deliver pressurized fuel to the fuel injectors 56.
The fuel injectors 56 are disposed in the air ducts 44 of the air
intake system 26 proximate the intake valve 48. The fuel injectors
56 may also be located in the combustion chamber 42 wherein the
fuel is injected directly into the combustion chamber 42.
[0036] The ignition system 24 includes spark plugs 58, ignition
coils 60, and ignition wires 62. A single spark plug 58 is disposed
in each of the combustion chambers 42. An ignition coil 60 is
disposed electrically between the powertrain control module 20 and
each of the spark plugs 58. The powertrain control module 20 sends
a low voltage electric signal to the ignition coils 60 where the
signal is stepped to a high-voltage signal required to create a
spark and then sent to the spark plugs 58 through the ignition
wires 62.
[0037] The exhaust system 30 collects exhaust gases from the
combustion process in the combustion chamber 42 and directs the
gases through a series of after-treatment mechanisms such as
catalytic converters and mufflers (not shown). Some of the exhaust
gases can be diverted back to the intake system for improved
combustion and fuel economy.
[0038] The powertrain control module 20 is electronically connected
to at least the engine 12 and transmission 14 and is preferably an
electronic control device having a preprogrammed digital computer
or processor, control logic, memory used to store data, and at
least one I/O peripheral. The control logic includes a plurality of
logic routines or sequence for monitoring, manipulating, and
generating data. The powertrain control module 20 controls the
operation of each of the engine 12 and transmission 14. The control
logic may be implemented in hardware, software, or a combination of
hardware and software. For example, control logic may be in the
form of program code that is stored on the electronic memory
storage and executable by the processor. The powertrain control
module 20 receives the output signals of several sensors throughout
the transmission 14 and engine 12, performs the control logic and
sends command signals to the engine 12 and transmission 14. The
engine 12 and transmission 14 receive command signals from the
powertrain control module 20 and converts the command signals to
control actions operable in the engine 12 and transmission 14. Some
of the control actions include but are not limited to increasing
engine 12 speed, changing air/fuel ratio, changing transmission 14
gear ratios, etc, among many other control actions.
[0039] For example, a control logic implemented in software program
code that is executable by the processor of the powertrain control
module 20 includes control logic for implementing a method of
operating the engine 12 in an active fuel management or cylinder
deactivation mode or method. The cylinder deactivation mode is
initiated to improve fuel consumption by cutting off fuel delivery
to or deactivating selected cylinders while torque demand on the
engine is less than the maximum torque available from the engine. A
portion of the cylinder deactivation mode is controlling the
operation of the engine as the engine is operating under cylinder
deactivation mode and the vehicle operator is requesting additional
torque. Such a portion of engine control is a cylinder reactivation
torque smoothing control method 100. An important goal of the
cylinder reactivation torque smoothing control method 100 is to
provide a smooth, measured increase in torque from the engine 12 as
the operator is requesting an increase in torque delivery to the
wheels 18.
[0040] A schematic of the engine control operation is illustrated
in FIG. 4 while a flowchart of the cylinder reactivation torque
smoothing control method 100 is shown in FIG. 5. For example, a
first condition that is required to begin the cylinder reactivation
torque smoothing control method 100 is that the engine 12 is
running in the cylinder deactivation mode. Next, the method begins
with a first step 102 of receiving a torque request t.sub.req from
the operator or driver. The torque request t.sub.req will typically
come in the form of an increase in accelerator pedal pressure;
however, the torque request t.sub.req can come in other forms
without departing from the scope of the disclosure. One such torque
request t.sub.req may result from an active or adaptive cruise
control. The torque request t.sub.req is compared to a high or fast
torque exit threshold t.sub.fast. In a second step 104, if the
torque request t.sub.req is greater than the fast exit threshold
torque t.sub.fast, then the variable torque reduction ratio r is
set to 1.0 r.sub.max in a third step 106. If the torque request
t.sub.req is not greater than the fast exit threshold torque
t.sub.fast, then the torque request t.sub.req is compared to the
slow exit threshold torque t.sub.slow in a fourth step 108. If the
torque request t.sub.req is less than the slow exit threshold
torque t.sub.slow, then a fifth step 110 sets the variable torque
reduction ratio r to 0.0 r.sub.min.
[0041] If the torque request t.sub.req is between the fast torque
exit threshold t.sub.fast and the slow exit threshold torque
t.sub.slow, a sixth step 112 sets the variable torque reduction
ratio r equal to the proportion that the torque request is between
the fast and slow exit threshold torques t.sub.fast, t.sub.slow.
Thus, the final torque engine output t.sub.f is set in the seventh
step 114 as the slow exit threshold torque t.sub.slow+the variable
torque reduction ratio r times the difference of the fast exit
threshold torque t.sub.fast and the slow exit threshold torque
t.sub.slow.
t.sub.f=t.sub.slow+r(t.sub.fast-t.sub.slow)
[0042] Once the final torque output t.sub.f is calculated for a
particular torque request t.sub.req, spark control is used to
smoothly increase the torque output from the previously deactivated
cylinders 38. For example, for any particular engine, the fast and
slow exit threshold torques t.sub.fast, t.sub.slow are particular
numbers for a given set of operating parameters found on calibrated
tables stored in the powertrain control module 20. In this manner,
the cylinder reactivation torque smoothing control method 100 is
capable of controlling engines of many displacements and
configurations without departing from the scope of the
disclosure.
[0043] While examples have been described in detail, those familiar
with the art to which this disclosure relates will recognize
various alternative designs and examples for practicing the
disclosed structure within the scope of the appended claims.
* * * * *