U.S. patent application number 09/853754 was filed with the patent office on 2001-09-13 for control apparatus and a control method for a vehicle.
This patent application is currently assigned to Hitachi, Ltd.. Invention is credited to Ishii, Junichi, Kuragaki, Satoshi, Minowa, Toshimichi.
Application Number | 20010020466 09/853754 |
Document ID | / |
Family ID | 18282791 |
Filed Date | 2001-09-13 |
United States Patent
Application |
20010020466 |
Kind Code |
A1 |
Minowa, Toshimichi ; et
al. |
September 13, 2001 |
Control apparatus and a control method for a vehicle
Abstract
A control device and a control method capable of eliminating a
torque variation in changing an air/fuel ratio and establishing a
compatibility of promotion in fuel economy with promotion in
drivability is provided. The device includes an outer environment
detector for detecting an outer environment in running a vehicle, a
running environment determining device for predicting a current
running environment in accordance with the outer environment, a
data storage device for storing data for changing a driving
characteristic, a selecting device for selecting the data, a
control quantity calculator for calculating a control quantity
based on the data, and a control actuator for controlling a control
object. The engine output is efficiently utilized since the
air/fuel ratio is changed in accordance with the change in the
running environment, and the fuel cost reduction and the promotion
of the drivability can be achieved since the selecting of the
air/fuel ratio is performed in accordance with the running
environment.
Inventors: |
Minowa, Toshimichi;
(Naka-gun, JP) ; Kuragaki, Satoshi;
(Hitachinaka-shi, JP) ; Ishii, Junichi; (Novi,
MI) |
Correspondence
Address: |
CROWELL & MORING, L.L.P.
Suite 700
1200 G Street, N.W.
Washington
DC
20005
US
|
Assignee: |
Hitachi, Ltd.
|
Family ID: |
18282791 |
Appl. No.: |
09/853754 |
Filed: |
May 14, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09853754 |
May 14, 2001 |
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09487595 |
Jan 19, 2000 |
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6260539 |
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09487595 |
Jan 19, 2000 |
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09346579 |
Jul 2, 1999 |
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6032646 |
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09346579 |
Jul 2, 1999 |
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08989024 |
Dec 11, 1997 |
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5947087 |
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08989024 |
Dec 11, 1997 |
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08816703 |
Mar 13, 1997 |
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5724944 |
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08816703 |
Mar 13, 1997 |
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08695345 |
Aug 9, 1996 |
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5638790 |
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08695345 |
Aug 9, 1996 |
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08365444 |
Dec 28, 1994 |
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Current U.S.
Class: |
123/478 ;
123/486 |
Current CPC
Class: |
F02D 2200/602 20130101;
F02D 35/0015 20130101; F02D 2400/12 20130101; F02D 2200/702
20130101; F02D 41/2406 20130101; F02D 41/1479 20130101; F02D 41/14
20130101; F02D 11/105 20130101; F02D 2250/18 20130101; F02D 41/1486
20130101; F02D 41/021 20130101; B60R 16/0236 20130101; F02D
2200/501 20130101; Y02T 10/84 20130101; F02D 41/023 20130101 |
Class at
Publication: |
123/478 ;
123/486 |
International
Class: |
F02M 051/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 28, 1993 |
JP |
5-334926 |
Claims
What is claimed is:
1. A control apparatus for controlling a control actuator in a
vehicle operating in a running environment, comprising: a memory
storing a plurality of data; a data selecting means for selecting
one of said plurality of data in accordance with a change in the
running environment to affect a change in the control actuator;
wherein said plurality of data includes at least one non-steady
state condition of the vehicle.
2. The control apparatus according to claim 1, wherein said
plurality of data further include steady-state conditions of the
vehicle.
3. The control apparatus according to claim 2, wherein said data
selecting means operates to first select a steady state condition
in said memory for a first running environment, and to next select
a non-steady state condition in said memory in response to said
change in the running environment.
4. The control apparatus according to claim 1, wherein said
plurality of data are corrected air/fuel ratio values used for
controlling an air/fuel ratio of an engine of the vehicle.
5. The control apparatus according to claim 4, further comprising:
an air flow quantity controlling means for operating to restrain a
torque variation which occurs during the selecting of the corrected
air/fuel ratio values.
6. The control apparatus according to claim 5, wherein said air
flow quantity controlling means is a throttle opening position
calculator.
7. The control apparatus according to claim 4, wherein the
corrected air/fuel ratio values are correction values determined by
an engine rotational speed and an engine load, said correction
values being classified into air/fuel ratios for a low engine
rotational speed condition and a no load condition, and into
air/fuel ratios for the engine load changing between a partial load
and a high load and a high load.
8. The control apparatus according to claim 1, wherein the running
environment is at least one of an external environment to the
vehicle such as a road incline, a traffic jam, an expressway and a
city road.
9. The control apparatus according to claim 8, further comprising:
a correcting means for operating to restrain a torque variation
when said one of the plurality of data is selected in accordance
with the change in the running environment.
10. The control apparatus according to claim 8, further comprising:
an outer environment detector for detecting the running
environment.
11. The control apparatus according to claim 10, wherein the outer
environment detector is at least one of an infrastructure
information detector, an outer vehicle-environment recognizing
sensor, and a running state detector.
12. The control apparatus according to claim 10, wherein the data
selecting means operates on a priority basis and comprises means
for prioritizing a drivability of the vehicle over fuel economy
when a plurality of the running environments overlap.
13. The control apparatus according to claim 12, wherein the
priority determining means prioritizes an air/fuel ratio for an
inclined road over an air/fuel ratio for a traffic jam.
14. A control apparatus for controlling a control actuator in a
vehicle operating in a running environment, comprising: a memory
storing a plurality of data; a data selecting means for selecting
one of said plurality of data in accordance with a change in the
running environment to affect a change in the control actuator; and
an air/fuel ratio controlling means for controlling the air/fuel
ratio in accordance with a torque change of the vehicle which is
not caused by an air/fuel ratio change.
15. A control apparatus for controlling a control actuator in a
vehicle operating in a running environment, comprising: a memory
storing a plurality of data; a data selecting means for selecting
one of said plurality of data in accordance with a change in the
running environment to affect a change in the control actuator; and
an air/fuel ratio controlling means for controlling an air/fuel
ratio in accordance with a change in an operating state condition
of the vehicle.
16. The control apparatus according to claim 15, wherein said
change in the operating state condition is at least one of a
changing from a partial load state condition to an idling state
condition, a speed changing condition, and a gear shift lever
shifting condition.
17. A control method for controlling a control actuator in a
vehicle operating in running environment, comprising the steps of:
detecting a change in the running environment to affect a change in
the control actuator; selecting at least one of plurality of data
stored in a memory of the vehicle in accordance with said change in
the running environment; calculating a control amount for
controlling said control actuator; controlling said control
actuator in accordance with said control amount, wherein said
plurality of data includes at least one non-steady state condition
of the vehicle.
18. The control method according to claim 17, wherein said
plurality of data further includes steady state conditions of the
vehicle.
19. The control method according to claim 18, wherein said
selecting step further comprises the step of selecting one
non-steady state condition in said memory in response to said
change in the running environment after selecting one steady state
condition in said memory for a first running environment.
20. The control method according to claim 19, wherein said
plurality of data are corrected air/fuel ratio values for
controlling an air/fuel ratio of an engine of the vehicle.
21. The control method according to claim 20, further comprising
the step of: operating to restrain a torque variation which occurs
during the selecting of the corrected air/fuel ratio values.
22. The control method according to claim 21, wherein said
operating step is carried out by a throttle opening position
controller.
23. The control method according to claim 20, further comprising
the step of: determining said corrected air/fuel ratio values by an
engine rotational speed and an engine load which are classified
into air/fuel ratios for a low engine rotational speed and a no
load, and air/fuel ratios for the engine load changing between a
partial load and a high load.
24. The control method according to claim 19, wherein said running
environment is at least one of an external environment to the
vehicle such as a road incline, a traffic jam, an expressway, and a
city road.
25. The control method according to claim 24, further comprising
the step of: operating to restrain a torque variation when said one
of the plurality of data is selected in accordance with the change
in the running environment.
26. The control method according to claim 24, wherein said step for
detecting the running environment is carried out by an outer
environment detector.
27. The control method according to claim 26, wherein said outer
environment detector is at least one of an infrastructure
information detector, an outer vehicle environment recognizing
sensor, and a running state detector.
28. The control method according to claim 26, wherein said
selecting step for at least one of a plurality of data stored in
said memory includes the step of prioritizing a drivability of the
vehicle over a fuel economy of the vehicle when a plurality of the
running environments overlap.
29. The control method according to claim 28, wherein said
prioritizing step prioritizes an air/fuel ratio for an inclined
road over an air/fuel ratio for a traffic jam.
30. A control method for controlling a control actuator in a
vehicle operating in a running environment, comprising the steps
of: detecting a condition of the vehicle; selecting at least one of
a plurality of data in accordance with the condition of the
vehicle; selecting the plurality of data characterized by
performing a control for changing an air/fuel ratio in accordance
with a torque change of the vehicle which is not caused by an
air/fuel ratio change.
31. A control method for controlling a control actuator in a
vehicle operating in a running environment, comprising the steps
of: detecting a condition of the vehicle; selecting at least one of
a plurality of data in accordance with the condition of the
vehicle; selecting the plurality of data characterized by
performing a control for changing an air/fuel ratio in synchronism
with a change in an operating state condition of the vehicle.
32. The control method according to claim 31, wherein said change
in an operating state condition is at least one of a changing from
a partial load state condition to an idling state condition, a
speed changing condition, and a gear shift lever changing
condition.
Description
FIELD OF THE INVENTION
[0001] This invention relates to a control apparatus and a control
method for a motor vehicle, and, in particular, to a control
apparatus and a control method for a motor vehicle for efficiently
controlling an engine power train in accordance with various
information such as a running environment of the motor vehicle and
the like.
BACKGROUND OF THE INVENTION
[0002] A known conventional control system, for instance, as
disclosed in Japanese Patent Laid Open No. Sho 62-126235,
determines an operating region in accordance with a change in an
operating state, that is, a change in an engine load (pressure in
the intake pipe, air/fuel ratio sensor signal or the like) and a
change in an engine rotational speed, for establishing
compatibility between fuel-economy and drivability, and reads a
target air/fuel ratio value which has been set for every operating
region, thereby changing the air/fuel ratio of an engine.
[0003] When the target air/fuel ratio is changed with the engine
load and the engine rotational speed as parameters as in the
conventional technology, a steady state condition is changed to
another steady state condition. The fuel quantity is then changed
during acceleration of the vehicle by which a torque variation is
generated. This produces a strange feeling for the vehicle operator
since the fuel quantity is changed during the acceleration.
Further, when a NOx reduction catalyst is not employed, the
air/fuel ratio considerably changes from an air/fuel ratio of 14.7,
which is the theoretical mixture ratio, to around an air/fuel ratio
of 24 for reducing a discharge quantity of Nox, by which the torque
variation is further increased.
SUMMARY OF THE INVENTION
[0004] There is therefore needed a control apparatus and a control
method capable-of achieving compatibility between promoting the
fuel economy and the drivability by eliminating torque variations
which occur in changing the air/fuel ratio during a running
operation of a motor vehicle.
[0005] These needs are met according to the present invention which
provides a control apparatus and method including an outer
environment detector for detecting the outer environment during the
running of the motor vehicle, a running environment determining
system for predicting a current running environment, for instance,
a road incline, a road with a traffic jam, and the like, in
accordance with the outer environment, a data storing device for
storing data used to change an operating characteristic in
accordance with the running environment, a switching system for
switching the data in accordance with the running environment, a
control quantity calculator for calculating a control quantity
based on the data selected from the data storing device and a
control actuator for controlling a control object. These systems
can be implemented in either a hardware circuit, or as software
applications operating on a microprocessor or the like.
[0006] It is an advantage of the present invention, constructed as
described above, that the data, such as the air/fuel ratio or the
like, is always switched taking into consideration the running
environment in a non-steady state condition, a speed changing
condition, a stopping condition, an idling condition, a operation
of a shift lever, and the like. Therefore, any unpleasant feeling
for the driver due to the torque variation accompanied by the
change in the air/fuel ratio is eliminated. Accordingly, a
reduction in the actual fuel cost and a promotion of the
drivability can both be achieved.
[0007] A detailed explanation will be given to embodiments of the
present invention based on the drawings as follows.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a block diagram of an embodiment of the control
system of the present invention;
[0009] FIG. 2 is a block diagram illustrating an example of the
construction of a specific control system according to the
embodiment in FIG. 1; FIG. 3 is a block diagram wherein control of
an air flow quantity is added to the fuel control system
illustrated in FIG. 2;
[0010] FIG. 4 is a conceptual diagram illustrating a specific
example of the switching of an air/fuel ratio;
[0011] FIG. 5 illustrates an example of a correction table diagram
of a target air/fuel ratio;
[0012] FIG. 6 is a control flow chart diagram illustrating the
operation of the present invention for a motor vehicle running in a
traffic jam;
[0013] FIG. 7 is a control flow chart diagram continued from FIG.
6;
[0014] FIG. 8 is a control flow chart diagram illustrating the
operation of controlling an air flow quantity;
[0015] FIG. 9 is a conceptual block diagram illustrating a
construction of the present invention in a motor vehicle;
[0016] FIG. 10 is a control flow chart diagram illustrating the
operation of an air/fuel ratio switching control;
[0017] FIG. 11 is a control flow chart diagram illustrating the
operation of the present invention for a motor vehicle running in
the overlapping conditions of a traffic jam and/or an uphill or a
downhill slope; and
[0018] FIG. 12 is a correlation diagram illustrating a relationship
between the road incline in a traffic jam and a corrected air/fuel
ratio.
DETAILED DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a block diagram of an embodiment of the control
system of the present invention. First, signals or images from an
outer environment detector 1 for detecting conditions of an outer
environment during the running of a motor vehicle, are input to a
running environment determining system 2 in a controller 41. The
running environment determining system 2 predicts the current
running environment for the motor vehicle, for instance, a road
incline, a traffic jam on a road, and the like, in accordance with
the signals detected by the outer environment detector 1. Next, a
data storing device 3 stores data used to change an operating
characteristic in accordance with the running environment. A
switching system 4 selects the data in the data storing device 3
based on the environment which has been determined by the running
environment determining system 2. A control quantity calculator 5
calculates a control quantity based on the selected data, and
outputs the control quantity to a control actuator 6, thereby
controlling a control object, such as the engine, transmission, or
the like.
[0020] FIG. 2 is a specific example of the embodiment illustrated
in FIG. 1. As in FIG. 1, signals or images from the outer
environment detector 1 for detecting the outer environment in the
running of a motor vehicle are input to the running environment
determining system 2, and the current running environments, for
instance, a road incline, a traffic jam on a road, or the like, are
predicted in accordance with the outer environment. Next, a
corrected air/fuel ratio storing device 7 stores corrected air/fuel
ratios in accordance with a plurality of running environment
conditions. These corrected air/fuel ratios are switched by the
switching system 4, and a desired air/fuel ratio of an engine is
achieved in accordance with the current running environment.
Further, a fuel quantity calculator 8 receives values which have
been calculated by the corrected air/fuel ratio storing device 7
and a basic fuel quantity calculator 9. The basic fuel quantity is
normally calculated by an air flow quantity and the engine
rotational speed. The final calculation of fuel quantity is
performed by calculating a correction coefficient based on the data
of the corrected air/fuel ratio storing device 7 and multiplying or
adding the coefficient to the basic fuel quantity. Further, the
calculated value is output to the fuel injection valve 13 based on
a reference signal of engine rotational speed.
[0021] FIG. 3 is a control block diagram in which the fuel control
illustrated by FIG. 2 further includes an air flow quantity
control. The fuel injection valve control is the same as in FIG. 2.
Further, a targeted driving shaft torque calculator 11 detects
input signals and calculates a targeted driving shaft torque which
is required by a driver using signals of the accelerator opening
position a, a vehicle speed Vsp, and the like. The targeted engine
torque calculator 12 calculates a targeted engine torque using the
targeted driving shaft torque, a torque converter characteristic of
the transmission, an engine characteristic, and the like, and
further based on the data from the corrected air/fuel ratio storing
device 7. Next, a throttle opening position calculator 13
calculates a targeted opening position for the throttle based on
the targeted engine torque, the engine rotational speed, and the
like. The targeted opening position is output to a throttle control
valve 14, which is electronically controlled by a motor or the
like. Accordingly, the addition of this air flow quantity control
can correct the engine torque which changes by a change in the
air/fuel ratio, by the air flow quantity thereby promoting the
drivability of the motor vehicle.
[0022] FIG. 4 illustrates a specific example of the switching of
the air/fuel ratio. In detecting the outer environment, first, one
method makes use of outer infrastructure information such as
information gathered from display boards installed on the roads or
road information gathered by an FM multiplex transmitter. Second,
another method detects outer environment information using an outer
vehicle environment recognizing sensor, such as a TV or video
camera, provided inside the vehicle. A third method makes use of
the processed data and operating signals of a vehicle (for
instance, vehicle speed, output shaft torque etc.). For detecting
the outer environment, a combination of the methods described
above, or an individual method, may be used. The method to be used
can be determined in accordance with the detection accuracy and the
circumstances of the application. Next, the running environment is
determined.
[0023] This includes information on the road incline, such as an
uphill or downhill, if a traffic jam is present, the steady state
or the acceleration state of an expressway, a city traffic driving
situation, and the like. These outer running environment conditions
are provided by the outer environment detector.
[0024] Further, an air/fuel ratio is selected in switching the
air/fuel ratio. The selected air/fuel ratio achieves compatibility
between the drivability and the fuel economy according to the
running environment. For instance, in case of an uphill road
incline and an expressway acceleration, the air/fuel ratio needs a
rich mixture ratio of about 13. This is because there is a high
probability that maximum engine output is required. Further, in the
case of a downhill road incline, a traffic jam, or steady state
condition on an expressway, the air/fuel ratio is determined to be
a lean mixture ratio of approximately 24. This is because a high
engine output is not necessary, thereby achieving a considerable
reduction in the fuel cost. Further, for the case of normal running
in a city area or the like, the air/fuel ratio is determined to be
at the theoretical mixture ratio of 14.7.
[0025] As shown in FIG. 5, a correction table for the air/fuel
ratio is shown with the engine rotational speed Ne as the abscissa
and the basic fuel injection width Tp as the ordinate. In the
region of a low engine rotational speed including the idling state,
and a low basic fuel injection width, the air/fuel ratio is
determined such that the combustion is stabilized. For example,
when better engines are developed, the engines can be driven by a
leaner mixture.
[0026] FIGS. 6 and 7 are control flow charts illustrating the
operation of the control system for a motor vehicle operating in a
traffic jam on a road. First, in step 15, the control system reads
a forward intervehicle distance Sf, a rearward intervehicle
distance Sr, a vehicle speed Vsp, a basic fuel injection width Tp
and an engine rotational speed Ne. In step 16, the operation
calculates a timewise change ASf of the forward vehicle distance by
the following equation (Equation 1):
.DELTA.Sf=[Sf(n)-Sf(n-1)]/[T(n)-T(n-1)] (Equation 1)
[0027] In step 17, the operation calculates a timewise change
.DELTA.Sr of the rearward intervehicle distance by the following
equation (Equation 2):
.DELTA.Sr=[Sr(n)-Sr(n-1)]/[T(n)-T(n-1)] (Equation 2)
[0028] In step 18, the operation calculates the acceleration G of
the driving vehicle by the following equation (Equation 3):
G=[Vsp(n)-Vsp(n-1)]/[T(n)-T(n-1)) (Equation 3)
[0029] In step 19, the operation calculates the mean vehicle speed
Vave of the driving vehicle by the following equation (Equation
4):
Vave(n)[Vsp(n)+ . . . +Vsp(n-k)]/(k+1) (Equation 4)
[0030] Further, in step 20, the operation performs a count for
memorizing the mean vehicle speed Vave (n-a) of "a" times
before.
[0031] That is, the operation determines whether "x" equals "a". If
"x" is not "a", the operation adds 1 to "x" in step 21 and proceeds
to step 24 in FIG. 7. If "x" equals "a", the operation substitutes
the mean vehicle speed Vave (n-a) of "a" times before, by Vave(n)
in step 22, and nullifies "x" in step 23. Next, in step 24 in FIG.
7, the operation determines whether the timewise change .DELTA.Sf
of the forward intervehicle distance which has been calculated in
accordance with Equation 1 is not larger than, for instance, 10
m/s. That is, when the timewise change .DELTA.Sf is large, it is
considered that the preceding vehicle has abruptly started and
there is a high probability of there being no vehicle in front of
the preceding vehicle. In step 25, the operation checks the
timewise change of the rearward intervehicle distance as in step
24, and determines whether the driving vehicle is being squeezed by
the forward and rearward vehicles due to the traffic jam. In step
26, the operation compares the acceleration G of the driving
vehicle. When the forward direction is stagnated, in starting the
driving vehicle, the starting acceleration is limited, and the
operation determines there is a high probability of a traffic jam
in a case wherein the acceleration is not larger than, for
instance, 0.5 q. Finally, in step 27, the operation employs the
value which has been calculated in step 22, and determines whether
the mean vehicle speed Vave(n-a) of "a" times before, is not larger
than, for instance, 5 km/h. If the mean vehicle speed of the
preceding several seconds is not larger than 5 km/h, the operation
determines that the state wherein the vehicle speed is not greater
than 5 km/h has continued for a while, that is, there is a high
probability of a traffic jam. Accordingly, the operation performs
an overall estimation of the judgments made from step 24 to step
27, and determines the traffic jam when all the judgments are
satisfied, and then proceeds to step 28. Further, when any one of
steps 24 through 27 is No, the operation proceeds to step 29 and
employs the corrected air/fuel ratio table of the running
environment which has been determined in the preceding operation.
In step 28, since the traffic jam has been determined, the
operation selects a lean mixture of 24 for the air/fuel ratio in
the corrected air/fuel ratio table. Further, in stet 30, the
operation calculates a corrected fuel injection coefficient k1 by a
function h(A/F) of the air/fuel ratio in step 28. In step 31, the
control system calculates a fuel injection width Ti by the basic
fuel injection width Tp and the corrected fuel injection
coefficient k1 and outputs it in step 32.
[0032] FIG. 8 is a control flow chart illustrating the operation of
controlling an air flow quantity. In a previously known technique,
the engine rotational speed Ne and a turbine rotational speed Nt of
the torque converter are detected, and a driving shaft torque Tt is
calculated, from which the engine is then controlled. In this known
method, the driving shaft torque Tt doesn't become the required
torque, because a controlling amount for the engine is supplied
using a value of the driving shaft torque Tt without using a real
engine torque Te. Therefore, the engine is not controlled by the
most suitable value. In accordance with the present invention, at
first a required targeted driving shaft torque Ttar is decided, and
a required targeted engine torque Tet is calculated. Then, the
engine is controlled as the real engine torque Te becomes the
targeted engine torque Tet. In this method, the engine is
controlled by the most suitable value, because the real engine
torque Te is controlled directly as it becomes the targeted engine
torque Tet. As shown with respect to FIG. 8, first, in step 33, the
control system reads the accelerator opening position a, the
vehicle speed Vsp, the engine rotational speed Ne, the turbine
rotational speed Nt, the corrected air/fuel ratio A/F, and a
change-gear ratio i. Thereafter, in step 34, the targeted driving
shaft torque calculator 11 (FIG. 3) calculates the targeted driving
shaft torque Ttar using a function f1 (.alpha., Vsp) of the
accelerator opening position a and the vehicle speed Vsp. In step
35, the targeted engine torque calculator 12 calculates the
targeted engine torque Tet using a function f2(Ttar, Ne, Nt, i, c,
.lambda.) of the targeted driving shaft torque Ttar, the engine
rotational speed Ne, the turbine rotational speed Nt, the
change-gear ratio i, a characteristic ratio c of the torque
converter, and a torque ratio .lambda. of the torque converter. In
step 36, the throttle opening position calculator 13 calculates the
targeted opening position .theta.t for the throttle using a
function f3(Tet, Ne, A/F) of the targeted engine torque Tet, the
engine rotational speed Ne, and the corrected air/fuel ratio A/F.
Then, in step 37, the control system supplies control signals to
the fuel injection valve 10.
[0033] FIG. 9 shows a system construction diagram of the present
invention. An engine 39 and a transmission 40 are mounted on a car
body 38. An air flow quantity, a fuel quantity, an ignition timing,
a speed change reduction ratio and the like are controlled by
signals from an engine power train controller 41. An intake port
injection system of a conventionally known type, an inner cylinder
injection system having a good control performance, or the like, is
employed in the fuel control. Further, TV or video cameras 42 for
detecting the outer environment and an antenna 43 for detecting the
infrastructure information are mounted on the car body 38. Images
of the TV cameras 42 are input into a running environment
determining system 44 and are image-processed thereby recognizing
forward and backward intervehicle distances, traffic signal
information, traffic signs and a road state condition. Further, the
antenna 43 is connected to an infrastructure information receiver
45. Traffic jam information, information regarding a traffic
accident, current position information of the vehicle in relation
to the surrounding infrastructure, are input from the
infrastructure information receiver 45 to a running environment
determining system 44. Further, map information, which has been
stored in a CD-ROM 46 or the like, is input to the running
environment determining system 44. The current running environment
is determined by the infrastructure information and the map
information. A signal corresponding to the running information is
output from the running environment determining system 44 and is
input to the engine power train controller 41. The air flow
quantity, the fuel quantity, the speed change reduction ratio, and
the like, corresponding to the running environment are controlled
based on the signal. Further, the throttle opening position
.theta., a signal indicative of speed changing operation FlgI, the
vehicle speed Vsp, the gear shift lever switch signal Isw and'the
like are input to the engine power train controller 41, which are
employed for changing control quantities, determining the running
environment and the like.
[0034] FIG. 10 is a control flow chart of an air/fuel ratio
switching control. In this invention, it is necessary to change the
air/fuel ratio in accordance with the running environment. It is
possible to prevent the torque variation due to the change in the
air/fuel ratio by performing the change of the air/fuel ratio in
synchronism with, for instance, stopping, speed changing, idling or
the like. First, in step 50, the control system reads the corrected
air/fuel ratio A/F, the throttle opening position .theta., the gear
shift lever switch signal Isw and the signal indicative of speed
change operation FlgI. In step 51, the control system determines
whether the current corrected air/fuel ratio of A/F(n) equals to
the preceding corrected air/fuel ratio A/F(n-1). When the current
corrected air/fuel ratio equals to the preceding corrected air/fuel
ratio, the control system proceeds to step 52, calculates the
corrected fuel injection coefficient kl by f4(A/F(n-1)] and holds
the preceding air/fuel ratio. Further, the control system carries
out A/F(n-1)=A/F(n-1) and outputs the corrected fuel injection
coefficient kl which has been calculated in step 52, in step 54.
Further, when the current corrected air/fuel ratio A/F(n) is
different from the preceding corrected air/fuel ratio A/F(n-1) in
step 51, the control system proceeds to step 55, checks the opening
position .theta. of the throttle, and determines whether the engine
is in an idling state condition or not. For instance, if the
opening position is not larger than 2 degrees, the control system
determines that the engine is idling. In step 56, the control
system determines whether the gear shift lever switch Isw(n) has
been changed. That is, when the operation checks the motion of the
gear shift lever, it is effective to the change of the air/fuel
ratio, because the state of engine is limited to stopping or gear
changing. In step 57, the control system determines whether the
signal indicative of gear changing FlgI is 1 or not. When the
signal is 1, it becomes possible to change the air/fuel ratio in
synchronism with the torque variation in the speed changing, and
the torque variation accompanied by the change of the fuel ratio
can be prevented. When either one of step 55 through step 57 is
YES, the control system proceeds to step 58, calculates the
corrected fuel injection coefficient kl by f4[A/F(n)] in
synchronism with the change period, and changes the air/fuel ratio
to a new target air/fuel ratio. Further, the control system carries
out A/F(n-1)=A/F(n) in step 5g and outputs the corrected fuel
injection coefficient kl which has been calculated in step 58, in
step 54.
[0035] FIG. 11 is a control flow chart in case wherein a traffic
jam and an uphill or a downhill condition are overlapped. For
instance, when a traffic jam is caused on an uphill road, an engine
output is required in correspondence to the uphill, and it is
necessary to cope with it by a variable air/fuel ratio. First, in
step 60, the control system reads a traffic jam signal JAM and a
road incline .beta.. In step 61, the control system determines
whether a traffic jam is caused, that is, whether JAM is 1 or not.
When JAM is 1, the control system proceeds to step 62 and carries
out the determination of the traffic jam flag as FlgJ=1. When JAM
is not 1, the control system proceeds to step 63 and carries out
the determination of the traffic jam flag as FlgJ=0. Next, the
control system determines whether the road incline .beta. is not
smaller than, for instance, 0.5%. When the road incline .beta. is
smaller than 0.5%, the control system determines that the road is a
flat road or a downhill road and the air/fuel ratio had better be a
lean mixture of about 24. By contrast, when the load incline .beta.
is not smaller than 0.5%, it is necessary to change the air/fuel
ratio in accordance with the incline. Therefore, when the road
incline .beta. is not smaller than 0.5%, the control system
proceeds to step 65 and caries out the determination of the uphill
flag as Flg .beta.=1. When the road incline .beta. is smaller than
0.5%, the control system proceeds to step 66 and carries out the
determination of the uphill flag as Flg .beta.=0. Further, in step
67, the control system determines Flg J AND Flg .beta.. When the
determination is true, the control system proceeds to step 68, and
when the determination is false, the control system proceeds to
RETURN. When the determination is true, the traffic jam and the
uphill road are overlapped. Therefore, in step 68, the control
system calculates the corrected air/fuel ratio A/F by a corrected
incline air/fuel ratio table shown in FIG. 11 and a function
f5(.beta.) of the road incline .beta.. Further, in step 69, the
control system calculates the corrected fuel injection coefficient
k1 by using the corrected air/fuel ratio A/F which has been
calculated in step 68, and outputs it in step 70.
[0036] FIG. 12 shows a corrected air/fuel ratio with respect to the
road incline in case of a traffic jam. In a traffic jam on a road
which is in a range from a flat road to a minus incline, the engine
output is not considerably needed, and the air/fuel ratio of about
24 is sufficient. By contrast, under the uphill incline condition,
the engine output which is required according to the angle of
incline, increases. Accordingly, it is necessary to reduce the
air/fuel ratio and to form a rich mixture. The actual fuel cost
performance can be promoted by the above control.
[0037] According to the present invention, the air/fuel ratio
changes at any time in accordance with the change in the running
environment. Therefore, it becomes possible to effectively utilize
the engine output and further the actual fuel cost performance is
promoted. The switching of the air/fuel ratios is always performed
in accordance with a running environment other than a steady state
condition such as speed changing, stopping, idling, shift lever
operation or the like. Therefore, the unpleasant feeling by the
torque variation accompanied by the change in the air/fuel ratio.
Accordingly, the reduction of fuel cost and the promotion of
drivability can be achieved.
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