`
`
`Ex. PGS 1026
`
`
`
`EX. PGS 1026
`
`
`
`
`
`

`

`United States Patent [19]
`Hosaka
`
`[II] Patent Number:
`[45] Date of Patent:
`
`4,671,235
`Jun.9, 1987
`
`[54] OUTPUT SPEED DEPENDENT THROTTLE
`CONTROL SYSTEM FOR INTERNAL
`COMBUSTION ENGINE
`
`Inventor: Akio Hosaka, Yokohama, Japan
`[75]
`[73] Assignee: Nissan Motor Company, Limited,
`Yokohama, Japan
`
`[21] Appl. No.: 698,872
`Feb. 6, 1985
`[22] Filed:
`Foreign Application Priority Data
`[30]
`Feb. 7, 1984 [JP]
`Japan .................................. 59-19364
`
`Int. Cl.4 ......................... F02D 9/08; F02D 41/00
`[51]
`[52] u.s. Cl •..................................... 123/352; 123/399
`[58] Field of Search ............... 123/352, 361, 399, 400,
`123/401, 478, 436; 180/176, 179
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`3,886,915 6/1975 Taplin ................................. 123/357
`4,301,883 11/1981 Collonia .......................... 123/352 X
`4,453,516 6/1984 Filsinger ......................... 123/352 X
`4,470,396 9/1984 Hasumi et at. .................. 123/478 X
`
`FOREIGN PATENT DOCUMENTS
`3209851 9/1983 Fed. Rep. of Germany .
`3210808 10/1983 Fed. Rep. of Germany .
`2009968 6/1979 United Kingdom .
`2039092 7/1980 United Kingdom .
`
`2109592 6/1983 United Kingdom .
`
`OTHER PUBLICATIONS
`Society of Automotive Engineers, Inc., "Microproces(cid:173)
`sor Controls Engine and Transmission", vol. 91, No. 8,
`Aug. 1983, pp. 42-45.
`Schwartz, et al, "Steuerung der Einspritzung und Zuen(cid:173)
`dung von Ottomotoren mit Hilfe der Digitalen Motore(cid:173)
`lektronik MOTRONIC" Bosch Techn. Berichte 7
`(1981) 3, pp. 139-151.
`Primary Examiner-Tony M. Argenbright
`Attorney, Agent, or Firm-Schwartz, Jeffery, Schwaab,
`Mack, Blumenthal & Evans
`ABSTRACT
`[57]
`A throttle valve control system for an internal combus(cid:173)
`tion engine electrically controls throttle valve angular
`position in order to control intake air flow rate through
`an air induction passage of an engine. The system em(cid:173)
`ploys an accelerator to produce a signal representative
`of a required or demanded output speed. Actual output
`speed is monitored by means of a speed sensor. The
`actual speed is compared with the output speed demand
`derived from the accelerator signal to obtain the differ(cid:173)
`ence therebetween. Feedback control is performed on
`the basis of the calculated difference so as to control the
`throttle valve angular position to increase or decrease
`the actual output speed toward the speed demand value.
`
`9 Claims, 20 Drawing Figures
`
`Ex. PGS 1026
`
`

`

`US. Patent
`Jun. 9, 1937
`U.S. Patent Jun 9, 1987
`
`‘Sheetl ofl4
`Sheet 1 of 14
`
`4,671,235
`4,671,235
`
`0:
`N
`
`2R I8R .7 I8..
`
`_j
`2L
`N
`
`,...... .
`HGJ
`
`0
`0
`0
`\
`
`
`
`
`_j
`
`Ex. PGS 1026
`
`Ex. PGS 1026
`
`

`

`U.S. Patent
`
`Jun. 9, 1987
`
`Sheet2 of14
`
`4,671,235
`
`FIG.2
`
`II
`
`FIG.3
`
`30
`
`Ex. PGS 1026
`
`

`

`~
`Vl
`•
`~
`
`L861‘6“HImama'8T1
`
`
`
`~ ('I) a
`~ = p
`... -\0
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`
`00
`-1
`
`
`FIG.4{A)
`
`,
`
`234
`I
`
`.
`
`\‘
`\
`
`
`244068 25 242 '90 494
`240W'
`
`188
`
`-192
`
`I39
`139
`
`233
`230
`\
`'··
`
`PRESSURE
`REGULATOR
`
`
`
`
`MH/
`
`I48” I58
`
`
`
`137
`
`FUEL PUMP
`
`
`
`
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`- --- -- -------- -···-- ----- -(cid:173)
`' - - - - -- ----- ---·-···-·-·- ·- -- ------
`
`-----
`
`"-( 352
`
`TO FIG. 4B
`
`Ex. PGS 1026
`
`I9
`
`324
`322
`
`Ex. PGS 1026
`
`

`

`U.S. Patent
`
`Jun. 9, 1987
`
`Sheet4 of14
`
`4,671,235
`
`FIG.4(B)
`
`1008
`
`1000
`
`.___c_Pu _ __.r
`
`I
`2000
`
`28
`25
`
`FROM
`FIG.4A
`
`263
`
`STARTER
`
`I
`259
`
`Ex. PGS 1026
`
`

`

`IGNITION SWITCH
`
`GEAR SELECT SWITCH
`
`ACCELERATOR POSITION SENSOR
`
`BRAKE SWITCH
`
`PARKING BRAKE SENSOR
`
`INPUT UNIT
`
`10
`36
`33
`34-
`35
`25
`17
`
`MAIN POWER SOURCE RELAY
`15 --fCoN. CONNECTED POWER SOURCE
`
`CRANKSHAFT TORGUE SENSOR
`
`120----1 CRANK ANGLE SENSOR
`121-
`122
`AIR FLOW METER
`123 ------fENGINE- TEMP SENSOR
`
`,FIG. 5
`
`POWER SOURCE RELAY
`
`DATA OUTPUT DISPLAY
`
`-~ 17
`
`~28
`
`1-
`z
`:::1
`
`~
`
`0 a:
`1-
`z
`0
`0
`
`THROTTLE VALVE ACTUATOR
`
`IDLE AIR FLOW ACTUATOR
`-
`
`FUEL INJECTION VALVE
`
`DISTRIBUTOR
`•...
`EGA CONTROL ACTUATOR
`
`194
`--------134
`196
`l----246
`
`- -
`-
`140
`OUTPUT SHAFT REV. SPEEDSENSOR
`141 ~ulstiAFT n)R-OUE SENSOR
`
`GEAR SELECT ACTUATORS
`- -- ·· --- -
`-
`TORQUE CONVERTER
`LOCK-UP ACTUATOR
`
`------ 402
`1/ 404
`
`~
`Cll
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`""d
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`
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`
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`
`Ex. PGS 1026
`
`

`

`U.S. Patent Jun 9,1987
`
`Sheet6 of14
`
`4,671,235
`
`FIG.6
`
`t
`
`w
`::::l
`0
`a:
`0 ....
`
`LEAN-
`
`--RICH
`
`FIG.7
`
`t
`
`w
`::::l
`0
`a:
`0
`1-
`
`EP EN Ee
`SMALL ---EGA RATE-- LARGE
`
`FIG.9
`
`w
`::::l
`0
`a:
`~
`
`VEHICLE SPEED
`
`-
`
`Ex. PGS 1026
`
`

`

`U.S. Patent
`
`Jun. 9, 1987
`
`Sheet7 of14
`
`4,671,235
`
`. FIG.B (a)
`t
`0
`~ ..J
`
`w
`~
`
`e, z w
`
`FIG.B (b)
`
`VEHICLE SPEED - -
`
`t
`0 q:
`0
`..J
`w
`~
`e,
`z
`w
`
`I
`
`I
`
`VEHICLE SPEED - -
`
`FIG.B (c)
`
`t
`
`0
`q:
`0
`..J
`w
`~
`e,
`z
`w
`
`VEHICLE SPEED
`
`Ex. PGS 1026
`
`

`

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`
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`
`tlll.IU
`
`1800
`
`/1820
`
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`
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`120
`120
`36
`33
`34
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`35
`121
`10
`122
`,_ ~
`123
`140
`- ...,
`141
`
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`
`!
`•
`1840 ----;:~ POWER SUPPLY C.
`1850 - H
`J
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`1870
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`1400--
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`
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`
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`
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`-
`
`1500
`
`17l0
`1\
`
`I
`1730
`
`Ex. PGS 1026
`
`

`

`U.S. Patent Jun 9, 1987
`
`Sheet9 of14
`
`4,671,235
`
`FIG.ll
`
`( RESET
`
`)
`
`INITIALIZE
`PROGRAM
`
`1- - 3000
`
`(I)
`/
`
`/
`
`['
`
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`........
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`3100
`
`....
`
`....
`
`'
`
`....
`
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`
`Ex. PGS 1026
`
`

`

`FIG .12( A )
`
`I
`
`I INITIALIZE
`
`PROGRAM
`
`5000
`
`5600, I
`EXTERNAL
`PULSE
`INTERRUPT
`
`5700"' I
`OVERFlOW
`INTERRUPT
`
`'
`
`I
`5110"
`CLOCK SIGNAL
`OUTPUT
`PROGRAM
`
`l
`5120"":"l
`A/D CONV.
`ACTIVATION
`PROGRAM
`
`-
`
`I
`-
`REV. MEASURE.
`END.
`INTERRUPT
`
`5510'\ l
`
`ENGINE STALL
`DEC. RPM
`COMPUTATION PG.
`l
`
`CONTROL
`PROGRAM
`I
`I
`INTERRUPT
`HANDLING PG.
`I
`I
`TIMER
`INTERRUPT
`
`5100,
`
`I
`I
`5130---...
`TIME SYNCH. JOB
`ACTIVATION RES.
`PROGRAM
`I
`I
`JOB EXECUTION
`PRIORITY
`PROGRAM
`I
`I
`START CONTROL
`PROGRAM
`
`~
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`
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`
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`CONTROL PG.
`
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`
`[
`
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`
`6750
`
`nROL I
`
`M
`
`I
`6100
`
`I
`DEC. CONTROL
`PROGRAM
`
`6200
`
`6300
`
`Ex. PGS 1026
`
`

`

`FIG.12(B)
`
`H
`
`4000
`
`I
`ANGLE
`COINCIDENT
`INTERRUPT
`
`I
`DATA RECEIVE
`INTERRUPT
`
`I
`
`A/D CONV. END
`
`52\10
`
`I 5200
`
`5~10
`
`I 58bO
`
`53~0
`
`I 53oo
`
`ANGLE SYNCH. JOB
`ACTIVATION RES.
`PROGRAM
`I
`
`RECEIVED
`DATA HAND. JOB
`ACT. RES. PG.
`I
`
`OPERATION STATE
`DEPENDENT JOB
`ACT RES. PG.
`I
`
`I
`PRIVILEGED
`INTERRUPT
`(EXTERNAL INTER.)
`
`I 54ho
`
`5410
`\
`POWER OFF DATA
`HOLDING
`PROGRAM
`
`----
`
`~QQ _ _, ~1-----..
`ENGINE STALL
`PREVENTION PG.
`
`STEADY-STATE
`CONTROL OAT A
`COMPUTATION
`PROGRAM
`
`LOW SPEED
`CORRECTION
`DATA
`COM PUT AT ION
`PROGRAM
`
`LEARNING
`CONTROL
`PROGRAM
`
`CHECK PROGRAM
`
`4100
`
`4200
`
`4300
`
`4400
`
`~
`VJ
`•
`
`~
`
`~
`
`\0
`
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`.. -\0
`
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`Cll
`
`t:r a --~ -~
`
`~ ...
`0\
`-J
`......
`...
`N w
`Ul
`
`Ex. PGS 1026
`
`

`

`U.S. Patent Jun 9, 1987
`FIG.13
`
`(
`
`Sheet 12 of14 4,671,235
`
`)
`
`START
`~
`· READ ACCELERATOR ~II 0
`POSITION VALUE
`
`t
`
`DERIVE DESIRED
`OUTPUT SPEED
`FROM LOOK-UP TABLE
`
`t
`
`READ ACTUAL
`OUTPUT SPEED
`
`20
`~'
`
`,____... 30
`41
`
`41 40
`QIFFERENCE BETWEEN ____.,
`ACTUAL & DESIRED
`
`• FIND
`SPEED VALUES '
`c
`
`END
`
`)
`
`FIG .14
`
`ACCELERATOR POSITION
`
`Ex. PGS 1026
`
`

`

`U.S. Patent Jun 9,1987
`
`Sheet 13 of14 4,671,235
`
`FIG.15
`c START )
`
`DERIVE
`P-COMPONENT
`
`:./ 6701
`
`v 6702
`
`v 6703
`
`DERIVE
`I-COMPONENT
`
`DERIVE
`D-COMPONENT
`
`CALCULATE
`P+I+D
`
`../ 6704
`
`v 6705
`
`.
`
`OUTPUT
`CONTROL SIGNAL
`
`c END
`
`Ex. PGS 1026
`
`

`

`U.S. Patent Jun 9,1987
`
`Sheet 14 of14 4,671,235
`
`FIG.16
`START J
`
`(
`
`READ ACCELERATOR
`POSITION VALUE
`
`L----4110
`
`READ SELECTED
`MODE INPUT VALUE
`
`v-4121
`
`ECONOMY
`
`MODE
`?
`
`4122
`(
`POWER
`
`DERIVE OUTPUT
`SPEED FROM
`ECONOMY CURVE
`
`DERIVE OUTPUT
`SPEED FROM
`NORMAL CURVE
`
`DERIVE OUTPUT
`SPEED FROM
`POWER CURVE
`
`4125
`I
`
`READ ACTUAL
`OUTPUT SPE-ED
`SIGNAL VALUE
`
`v-4130
`
`FIND DIFFERENCE
`BETWEEN DESIRED &
`ACTUAL SPEED
`
`_.-- 4140
`
`END J
`
`(
`
`Ex. PGS 1026
`
`

`

`1
`
`4,671,235
`
`OUTPUT SPEED DEPENDENT THROTTLE
`CONTROL SYSTEM FOR INTERNAL
`COMBUSTION ENGINE
`
`2
`sion of the accelerator pedal. Specifically, in order to
`obtain good engine response characteristics to the ac(cid:173)
`celerator pedal position, the output torque produced by
`the engine must precisely correspond at all times to that
`5 demanded manually by means of the accelerator pedal.
`However, in practice, the engine output torque trans(cid:173)
`mitted to the vehicular driving wheels tends to fluctuate
`due to environmental conditions and/or production
`errors. For example, it is notorious that engine output
`10 characteristics fluctuate significantly, even to a disturb(cid:173)
`ing extent, as the engine warms up from a cold-weather
`start. Furthermore, many vehicles suffer shift-shock
`during shifting of the automatic power transmission due
`to deviations in engine speed and thus of engine output.
`15 This also degrades not only handling but also riding
`comfort.
`Therefore, it would be desirable for the vehicular
`power train to provide uniform accelerator response so
`as to constantly produce an optimal engine output speed
`at every accelerator position and in every transmission
`gear position.
`
`BACKGROUND OF THE INVENTION
`The present invention relates generally to a throttle
`valve position control system for an internal combus(cid:173)
`tion engine, in which an electrically or electromagneti(cid:173)
`cally operable throttle valve actuator is employed for
`controlling the throttle valve angular position depend(cid:173)
`ing upon the degree of depression of an accelerator
`pedal. More particularly the invention relates to a throt(cid:173)
`tle valve position control system which can control the
`throttle valve angular position depending not only on
`the accelerator pedal depression but also the difference
`between the actual output speed of the engine and the
`desired output speed for optimization of engine perfor-
`mance.
`Such throttle valve position control systems have 20
`been disclosed in European Patent First Publications
`Nos. 01 14 401, 01 21 937, 01 21 938, and 01 21 939. In
`these prior proposals or developments, the throttle
`valve angular position is generally controlled by an
`electromagnetic actuator associated with the throttle 25
`valve. A throttle control signal is produced depending
`upon the degree of depression of an accelerator pedal as
`indicated by a signal generated at the accelerator pedal.
`A similar throttle control system has also been dis(cid:173)
`closed in Japanese Patent First Publication (Tokkai) 30
`Showa No. 56-107925, published on Aug. 27, 1981. This
`document discloses an electronic fuel injection control
`system -for a spark ignition internal combustion engine,
`which includes a throttle valve servo mechanism opera(cid:173)
`tive to control a throttle valve angular position depend- 35
`ing upon the degree of depression of an accelerator
`pedal.
`The aforementioned control systems are capable of
`controlling the throttle valve to a desired angular posi(cid:173)
`tion corresponding to the depression rate of the acceler- 40
`ator pedals. Therefore, those systems may successful in
`controlling air induction at a rate corresponding to the
`accelerator depression degree. Theoretically, control of
`the throttle valve angular position implies direct control
`of engine output to obtain desired engine performance. 45
`However, in practice, due to production errors among
`individual engines and the wide range of possible envi(cid:173)
`ronmental conditions, engine output does not necessar-
`ily correspond to the demand on the engine throughout
`the range of throttle valve angular positions.
`There have been proposals for controlling engines or
`power trains including the engine and a power transmis(cid:173)
`sion to obtain output torque precisely corresponding to
`the output demand. SAE Technical Paper 830423, by
`the Society of Automotive Engineering, discloses a 55
`power train control system controlling the engine in a
`discrete manner by controlling the power transmission.
`In controlling the engine, the engine controller detects
`data from various points in the engine and adjusts fuel
`supply, ignition timing, EGR flow rate and intake air 60
`flow rate to optimal values derived from computations
`on the detected data. In controlling the transmission, a
`transmission controller detects engine load and vehicle
`speed, and derives the gear ratio to be established by the
`transmission and performs lock-up control on the basis 65
`of the results of computations on the detected data.
`Another important factor in overall vehicle perfor(cid:173)
`mance is good response of the driving torque to depres-
`
`-
`
`SUMMARY OF THE INVENTION
`Therefore, it is an principle object of the present
`invention to provide a throttle valve control system
`which can control the throttle valve angular position to
`consistently produce an engine output precisely corre(cid:173)
`sponding to an accelerator position.
`Another object of the invention to provide a throttle
`valve control system which allows variation of re(cid:173)
`sponse characteristics in accordance with various preset
`operation modes.
`A further object of the present invention is to provide
`a method for controlling a throttle valve angular posi(cid:173)
`tion so that the engine output precisely corresponds to
`the demand indicated by an accelerator position.
`In order to accomplish the aforementioned objects, a
`throttle valve control system, according to the present
`invention, includes an accelerator position sensor moni(cid:173)
`toring the position of an accelerator and producing an
`accelerator position indicative signal, a first arithmetic
`means deriving an output speed demand value in accor(cid:173)
`dance with the accelerator position indicative signal
`value, an output speed sensor for monitoring output
`speed at the output end of a power train including an
`internal combustion engine and a power transmission
`and producing an output torque indicative signal, a
`second arithmetic means comparing the output speed
`50 demand value derived by the first arithmetic means
`with the output speed indicative signal value which is
`representative of an actual output speed to derive the
`difference between the demand speed and the actual
`speed, and a third arithmetic means responsive to the
`accelerator position indicative signal and the difference
`between the demand speed and the actual speed to de-
`rive a correction value by which to adjust the position
`of a throttle valve toward a desired position at which
`the demand speed and actual speed essentially coincide.
`Preferably, the system includes a manual selector
`which allows a user to select one of various operation
`modes of the power train, which various operation
`modes correspond to unique response characteristics of
`control.
`In accordance with one aspect of the invention, a
`throttle valve control system comprises a manually
`operable output speed demand input means for produc(cid:173)
`ing an output speed demand indicative signal having a
`
`Ex. PGS 1026
`
`

`

`4,671,235
`
`3
`value varying according to preset vlfi'iation characteris(cid:173)
`tics in accordance with manual operation, a first sensor,
`associated with a vehicular power train including the
`engine, for monitoring the actual output speed of the
`power train and producing an actual speed indicative 5
`signal having a value proportional to the output speed
`of the power train, an intake air flow rate adjusting
`means, associated with an air induction passage of the
`engine, for controlling air flow therethrough, the intake
`air flow rate adjusting means being responsive to a 10
`control signal to adjust the intake air flow rate in accor(cid:173)
`dance therewith, and a controller receiving the output
`speed demand indicative signal and the actual speed
`indicative signal and deriving the difference between
`the signal values thereof, the controller producing the 15
`control signal having a value corresponding to the de(cid:173)
`rived difference and thereby controlling the intake air
`flow rate adjusting means to adjust the actual output
`speed of the power train toward the manually input
`speed demand.
`According to another aspect of the invention, an air
`induction rate control system for an internal combus(cid:173)
`tion engine comprises a manually operable accelerator
`for controlling air induction rate through an air induc(cid:173)
`tion passage, a throttle valve disposed pivotably within 25
`the air induction passage, the angular position of which
`depends upon the manually selected position of the
`accelerator, a first sensor associated with the accelera(cid:173)
`tor for producing a first sensor signal having a value
`varying according to the position of the accelerator, a 30
`second sensor monitoring output of a power train in(cid:173)
`cluding the engine and producing a second sensor signal
`having a value indicative of the output speed of the
`power train, a third arithmetic means, responsive to the
`first sensor signal for deriving an output speed demand 35
`on the basis of the first sensor signal value, a fourth
`arithmetic means, responsive to the second sensor signal
`and the output of the first arithmetic means, for deriving
`the difference between the second sensor signal value
`and the first arithmetic means output value and deriving 40
`a control signal having a value corresponding to the
`derived difference between the second sensor signal
`value and the first arithmetic means output value, and a
`throttle valve servo mechanism responsive to the con(cid:173)
`trol signal for adjusting the throttle valve angular posi- 45
`tion by an amount corresponding to the value of the
`control signal.
`According to a further aspect of the invention, a
`throttle valve control system for an internal combustion
`engine comprises an manually operable accelerator, a 50
`throttle valve disposed within an air induction passage
`of the engine for controlling intake air flow rate there(cid:173)
`through, an electrically operable throttle valve servo
`mechanism associated with the throttle valve to control
`the open degree of the latter according to a control 55
`signal, a first sensor associated with the accelerator for
`monitoring the position of the accelerator and produc(cid:173)
`ing a first sensor signal indicative of the position of the
`accelerator, a power train including the engine and
`having an output shaft for driving vehicular driving 60
`wheels, a second sensor associated with the output shaft
`of the power train for monitoring output speed thereon,
`the second sensor producing a second sensor signal
`indicative of the output speed on the output shaft, and a
`controller receiving the first sensor signal and second 65
`sensor signal, deriving an output speed demand on the
`basis of the first sensor signal value according to preset
`characteristics of variation of output speed demand
`
`4
`depending upon the first sensor signal value, deriving
`the difference between the derived output speed de(cid:173)
`mand and the second sensor signal value representative
`of the actual output speed, and generating a control
`signal acting on the throttle valve servo mechanism so
`as to reduce the difference to zero.
`On the other hand, the aforementioned and other
`objects may be achieved by a process or method of
`controlling a throttle valve angular position, in which
`accelerator operating position is generally taken as prin(cid:173)
`ciple feature of throttle valve position control to derive
`the throttle valve operating position. The accelerator
`position dependent operation position of the throttle
`valve is modified depending upon the difference be(cid:173)
`tween actual speed at the output end of a power train
`and a demand speed value derived from the accelerator
`position.
`In the preferred method, operation mode of the
`20 power train may be selected from among various preset
`operation modes. The demand speed is adjusted with
`respect to the selected operation mode.
`According to a still further aspect of the invention, a
`process for controlling intake air flow rate through an
`air induction system of an internal combustion engine
`by means of a throttle valve, comprises the steps of
`deriving a desired magnitude of speed to be outputted
`through a power train including the engine on the basis
`of the position of a manual accelerator, monitoring
`actual output speed on the power train, calculating the
`difference between the desired speed and the actual
`speed, deriving a control signal having a value acting to
`reduce the difference between the desired speed and the
`actual output speed toward zero, and feedback control(cid:173)
`ling a throttle valve servo system associated with the
`throttle valve so as to actuate the throttle value to a
`degree corresponding to the control signal value.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`The present invention will be understood more fully
`from the detailed description given herebelow and from
`the accompanying drawings of the preferred embodi(cid:173)
`ments of the invention, which, however, should not be
`taken to limit the invention to the specific embodiments
`but are for explanation and understanding only.
`In the drawings:
`FIG. 1 is a diagram of an automotive vehicle to
`which the preferred embodiment of a power train con(cid:173)
`trol system including a throttle valve control system
`according to the present invention is applied;
`FIG. 2 is an elevation of an accelerator pedal cooper(cid:173)
`ating with an accelerator position sensor to be em(cid:173)
`ployed in the throttle valve control system of the inven(cid:173)
`tion;
`FIG. 3 is a perspective view of a throttle valve actu(cid:173)
`ating servo mechanism in the preferred embodiment of
`the throttle valve control system according to the pres(cid:173)
`ent invention;
`FIGS. 4(A) and 4(B) together form a diagram of an
`engine control system to which the preferred embodi(cid:173)
`ment of the throttle valve control system is applicable;
`FIG. 5 is a schematic block diagram illustrating a
`control unit and its various input and output signals;
`FIG. 6 shows how output torque and fuel consump(cid:173)
`tion rate of an engine vary with respect to air/fuel ratio;
`FIG. 7 shows how output torque and fuel consump(cid:173)
`tion vary with respect to EGR rate;
`
`Ex. PGS 1026
`
`

`

`4,671,235
`
`5
`FIGS. S(A), S(B) and S(C) show optimal shift pat(cid:173)
`terns for an ECONOMY mode, a NORMAL mode and
`a POWER mode, respectively;
`FIG. 9 shows optimal lock-up ranges for the ECON(cid:173)
`OMY mode, the NORMAL mode and the POWER 5
`mode of FIG. 8;
`FIG. 10 is a detailed block diagram of a control unit
`in the throttle valve control system according to the
`invention;
`FIG. 11 is a diagram illustrating the control concepts 10
`the control unit of FIG. 10;
`FIGS. 12(A) and 12(B), when combined, illustrate in
`detail the control relationship among programs stored
`in the control unit;
`FIG. 13 is a flowchart of a correction value deriva- 15
`tion program executed by the control unit of FIG. 10;
`FIG. 14 is a graph of the output torque demand in
`terms of accelerator pedal position;
`FIG. 15 is a flowchart of a throttle valve CLOSED
`LOOP control program according to the present inven- 20
`tion; and
`FIG. 16 is a flowchart of a modified correction value
`deriving program executed by the control unit of FIG.
`10.
`
`6
`ling the open angle of a throttle valve (FIG. 3) so as to
`control intake air flow rate, in the case of a gasoline
`engine, or by controlling a fuel injection pump so as to
`control the fuel delivery rate, in the case of a Diesel
`engine. The accelerator 11 of the shown embodiment
`works in conjunction with an accelerator position sen-
`sor 33 to produce an electrical signal with a value de(cid:173)
`pending upon the operating position of the accelerator,
`which electric signal will be referred to hereafter as
`"accelerator position signal". The accelerator position
`sensor 33 is connected to an electrically operated. actua-
`tor 30 mechanically connected to a throttle valve 32 for
`operating the latter, as shown in FIG. 3. In the case of
`a Diesel engine, the actuator 30 may be coupled to a
`governer limiting the fuel delivery rate.
`Control of engine speed with the aid of an accelerator
`signal has been illustrated in European Patent First
`Publications Nos. 01 14 401, 01 06 360, 01 21 939, 01 21
`938 and 01 21 937. The contents of the above identified
`European Patent Applications are hereby incorporated
`by reference.
`The engine speed thus depends upon the position of
`the accelerator 11. The output torque of the engine
`25 varies according to engine output characteristics spe(cid:173)
`cific to each individual engine. The engine output is
`transmitted to the rear driving wheels 2R and 2L
`through the power transmission 4, the propeller shaft 5,
`the differential gear 7 and drive axles SR and SL in a per
`se well-known manner, as set forth above. Thus, the
`vehicle is driven by the engine. A brake pedal 12 is
`provided to allow the driver decelerate and/or stop the
`vehicle while the vehicle is moving. The brake system
`also includes a parking brake arrangement with a man-
`ual parking brake lever or pedal 13.
`In the shown embodiment, the power transmission 4
`comprises an automatic transmission which may be
`coupled to a torque converter (not shown) and which
`operates in one of a number of discrete gear positions,
`e.g. FIRST gear position, SE<:;OND gear position,
`DRIVE position, NEUTRAL position, REVERSE
`gear position and PARK position. If necessary, the
`automatic power transmission 4 may be connected to a
`control unit 1000 which controls shifting operations
`according to preset shift patterns related to vehicle
`speed, engine speed, engine load conditions and so
`forth. Normally, the automatic power transmission 4 is
`associated with a transmission gear selector 14 which
`allows the driver to select one of the aforementioned
`transmission gear positions. Control of the automatic
`power transmission by means of a microprocessor such
`as in the control unit 1000 is well known and requires no
`detailed description thereabout. However, for the sake
`of disclosure, the applicant hereby incorporates by ref-
`erence U.S. patent application Ser. No. 678,886, filed
`Dec. 6, 1984 assigned to the same assignee as herein.
`The controller or control unit 1000 is connected to
`the battery 15 through a connector line 16a to receive
`electrical power. A power source relay 17 is interposed
`in the connector line 16a, which relay 17 is coupled to
`the ignition switch to establish electrical communica-
`tion between the battery 15 and the control unit 1000
`when the ignition switch 10 is in either the ION position
`or the START position. The control unit 1000 is also
`connected to the battery 15 via an auxiliary connector
`line 16b which continuously establishes electrical com-
`munication between the battery and the control unit.
`The battery power supplied through the auxiliary con-
`
`45
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENT
`Referring now to the drawings; the vehicle illustrated
`in part in FIG. 1 has a front-engine, rear-wheel-drive
`power train which arrangement will be referred to here- 30
`after as "FR arrangement". In the FR arrangement, an
`internal combustion engine 3 is coupled to a power
`transmission 4 which is, in turn, connected to a differen(cid:173)
`tial gear 7 through a propeller shaft 5. A pair of rear
`wheels 2R and 2L are driven by the engine output trans- 35
`mitted through the power transmission 4, the propeller
`shaft 5, the differential gear 7 and drive axles SR and SL,
`and thus serve as driving wheels. Front wheels 1R and
`1L freely rotate according to vehicular movement as
`driven by the rear driving wheels 2R and 2L. The front 40
`wheels lR and lL are associated with a per se well(cid:173)
`known steering system for controlling the vehicle trav(cid:173)
`elling direction. The steering system includes a steering
`shaft 9 for manual selection of the vehicle travelling
`direction.
`The engine 3 is energized by an ignition system in(cid:173)
`cluding an ignition switch 10. As is well known, the
`ignition switch 10 has several discrete switch positions,
`namely an OFF position in which a vehicle battery 15 is
`disconnected from a vehicle accessories such as a vehi- 50
`cle audio system, an air conditioner system, and from an
`ignition coil, an ACC position in which the battery 15 is
`connected only to the vehicular accessories while re(cid:173)
`maining out of electrical communication with the igni(cid:173)
`tion coil, an ION position in which the battery is con- 55
`nected to both the vel:;licle accessories and the ignition
`coil, and a START position in which the battery is
`connected only to the ignition coil. As is well known,
`the ignition system further comprises a distributor,
`spark ignition plugs inserted into each engine cylinder, 60
`and a circuit breaker or power transistor which is gated
`by an ignition control signal produced at a given timing
`by a control unit 1000.
`The engine is also associated with an accelerator 11,
`such as accelerator pedal manually operated by a driv- 65
`er's foot or a hand-operated accelerator such as is used
`on motorcycles. The accelerator 11 is generally de(cid:173)
`signed to control engine revolution speed by control-
`
`Ex. PGS 1026
`
`

`

`4,671,235
`
`25
`
`7
`nectar line 16b may serve as back-up power for main(cid:173)
`taining data in memories in the control unit.
`The ignition switch 10 produces a signal indicative of
`engine cranking while it is in the START position. The
`signal produced by the ignition switch 10 while the 5
`engine is cranking will be referred to hereafter as
`"starter signal". The starter signal of the ignition switch
`10 is transmitted to the control unit 1000 via a line 18.
`The accelerator position is relayed to the control unit
`1000 by the accelerator position sensor 33. The acceler- 10
`ator position sensor may comprise a known potentiome(cid:173)
`ter and is connector to the control unit 1000 for input of
`the accelerator position signal via a line 19. The brake
`pedal 12 is associated with a brake switch 34 which
`produces a signal indicative of application of the brakes 15
`while the brake pedal is being depressed for decelerat(cid:173)
`ing or stopping the vehicle. The brake switch 34 is
`well-known and also energizes a brake lamp (not
`shown) while the brakes are operating. The brake
`switch 34 is connected to the control unit 1000 via a line 20
`20 which supplies a signal indicative of application of
`brakes, which will be referred to hereafter as "brake
`signal". The parking brake 13 is also coupled with a
`parking brake switch 35 which closes in response to
`application of the parking brake 13 to produce a signal
`indicative thereof, which signal will be referred to here(cid:173)
`after as "parking brake signal". The parking brake ~ig­
`nal is fed to the control unit 1000 via a line 21.
`A transmission gear position sensor 36 disposed near 30
`. the transmission gear selector 14 produces a signal in(cid:173)
`dicative of the selected transmission gear position,
`which signal will be referr