.
`
`U?lted States Patent [19]
`Taniguchi
`
`US005137001A
`
`[11] Patent Number:
`[45] Date of Patent:
`
`5,137,001
`Aug. 11, 1992
`
`[54] CONTROL APPARATUS F011 AN ENGINE
`_
`__
`[75] Inventor: Nobutake Taniguchi, H1meJ1, Japan
`[73] Assignee: Mitsubishi Denki K.K., Tokyo, Japan
`[21] App1.No.: 653,911
`[22] Filed:
`Feb. 12, 1991
`[30]
`Foreign Application Priority Data
`Feb. 23, 1990 [JP]
`Japan .., ............................... .. 243624
`
`[51] Int. c1.5 ......................................... FOZM 51/00
`[52] US. Cl. ............................... .. 123/494; 123/492
`[58] Field of Search .............. .. 123/494, 492; 73/ 118.2
`[56]
`References Cited
`U.S. PATENT DOCUMENTS
`
`4,706,681 11/1987 Wataya ............................. .. 123/494
`4,719,890 l/l988 Watava et a1. .
`4,807,581 2/ 1989 Nishikawa ......................... .. 123/492
`4,905,155 2/1990 Kanno ..... ..
`.
`4,951,209 8/ 1990 Nagaishi
`4,957,088 9/ 1990 Hosaka .... ..
`
`4,967,715 11/1990 Hosaka .............................. .. 123/494
`4,976,243 12/1990 Sano .................................. .. 123/492
`
`FOREIGN PATENT DOCUMENTS
`0202359 11/1983 Japan ................................. .. 123/494
`
`Primary Examiner-Carl S. Miller
`Attorney, Agent, or Firm-Sughrue, Mion, Zinn
`Macpeak 8L Seas
`ABSTRACT
`[57]
`An engine control apparatus has an intake air quantity
`detector which detects an intake air quantity to an en
`gine, a controller which controls the engine in response
`to the output of the intake air quantity detector a load
`detecting detector which detects a load to the engine,
`and a clip device the output of the intake air quantity
`detecting means at a second value when a ?rst time has
`passed after the load of engine has reached a predeter
`mined value or higher.
`
`5 Claims, 5 Drawing Sheets
`
`1- — * — _ . — . _ _ _ . — u ~ _ — . _ _ _ _ — — _ _ _ ~ _ _ _ ''—__I
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`TOYOTA Ex. 1126, page 1
`Toyota v. Hagenbuch
`IPR2013-00638
`
`

`

`US. Patent
`
`Aug. 11, 1992
`
`Sheet 1 of 5
`
`5,137,001
`
`FIGURE, |
`
`1
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`2
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`3
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`
`START swncu \1 1
`
`TOYOTA Ex. 1126, page 2
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`IPR2013-00638
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`

`

`US. Patent
`
`Aug. 11, 1992
`
`Sheet 2 of 5
`
`5,137,001
`
`cm
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`TOYOTA Ex. 1126, page 3
`Toyota v. Hagenbuch
`|PR2013-00638
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`TOYOTA Ex. 1126, page 3
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`IPR2013-00638
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`
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`

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`US. Patent ~
`
`Aug. 11,1992
`
`Sheet 3 of 5
`
`5,137,001
`
`FIGURE 3
`
`-'-4oo ~3oo 260 406-50 0 AFNmmHg)
`
`INTAKE AIR LOAD (PRESSURE)
`
`TOYOTA Ex. 1126, page 4
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`IPR2013-00638
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`

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`US. Patent
`
`Aug. 11, 1992
`
`Sheet 4 of5_
`
`,
`
`‘5,137,001
`
`(a)
`
`‘
`
`'
`
`180
`
`FIGURE 4
`
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`
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`
`(b)
`
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`(C)
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`
`TOYOTA Ex. 1126, page 5
`Toyota v. Hagenbuch
`IPR2013-00638
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`

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`US. Patent
`
`Aug. 11, 1992
`
`Sheet 5 of 5
`
`5,137,001
`
`FIGURE 5
`
`C TDCTNTERRUPTION ROUTINE )
`
`CALCULATE AN AVERAGED INTAKE AIR
`QUANTITY BETWEEN TDC
`
`‘102
`
`HIGH LUAD?
`
`1(33
`SET Cmox COUNTER
`
`195
`COUNT DOWN
`Cmux COUNTER
`
`READ UPPER LIMIT Amox
`
`.~—
`
`A(n)>Amax ?
`
`A(n)= Amax
`
`END
`
`TOYOTA Ex. 1126, page 6
`Toyota v. Hagenbuch
`IPR2013-00638
`
`

`

`1
`
`CONTROL APPARATUS FOR AN ENGINE
`
`15
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`5,137,001
`2
`the engine. A timer 9h is to effect a one-shot operation
`of the pulse width in time with a TDC falling point in
`the output signal of the crank angle sensor 10, whereby
`the injector 8 is actuated through an injector driving
`circuit 91'. The basic'fuel injection quantity of the injec
`tor 8 corresponds to the intake-air quantity per one
`revolution of the engine or the charging efficiency.
`Generally, there takes place a pulsation of air or a
`reverse-?ow of air in a low-speed-highaload area (1,000
`-3,000 rpm and ‘50 mmI-Ig-O mmHg, in a case that no
`turbo charger is used) during the operation of the en
`gine. In this case, there occurs an erroneous measure
`ment by the AFS 2 due to the pulsation of air or the
`reverse flow of air.
`FIG. 3 is a graph showing the relation of an air flow
`rate (the ordinate), boost pressure, i.e. a negative intake
`air pressure P (the abscissa) and a revolution speed
`(rpm) as parameters wherein the output of the AFS 2
`(hot wire type) is sampled every 1 ms and the sampled
`output is converted into the flow rate wherein the value
`of the flow rate is averaged with respect to one air
`intake stroke.
`As is clear from FIG. 3, the air flow rate A(n), when
`there occurs a reverse ?ow of air, shows a fairly large
`value in comparison with an actual air flow rate in the
`above-mentioned low-speed-high~load area in the en
`gine operation. In order to eliminate such disadvantage,
`there has been considered that an upper limit value is
`determined on the extension line (indicated by a broken
`line) for each of the revolution speed levels at a point of
`a boost pressure of P=O mmHg or a certain charging
`efficiency (i.e., 0.9) so that the value of intake air flow
`rate is clipped. Thus, by limiting the intake air ‘flow rate
`A(n) to be a value which is subjected to the clipping
`treatment, an appropriate intake air flow rate can be
`obtained (when the engine is in a steady state) even in
`the above-mentioned low-speed-high-load area of the
`engine operation.
`In the conventional control apparatus, however,
`there was found an overshoot in the air flow rate de
`tected by the AFS 2 (as indicated by a solid line A in
`FIG. 4b) owing to an amount of air remaining in the
`surge tank and the intake manifold 5 when the automo
`bile is rapidly accelerated, i.e. when the throttle valve is
`rapidly opened from the entirely closed state as shown
`by the solid line E in FIG. 4d. The detected air flow rate
`is not the value which is excessively detected due to the
`reverse flow of air, but is the actual flow rate. Accord
`ingly, it is not suitable for clipping the air flow rate at
`the maximum air flow rate C (as indicated by one-dot
`ted chain line) where the throttle valve is entirely
`opened. Namely, the conventional control apparatus
`wherein the upper limit is provided for each revolution
`speed level and the intake air quantity to the engine is
`clipped by the upper limit value, can not provide a good
`result when the engine is accelerated.
`
`30
`
`BACKGROUND OF THE INVENTION
`lField of the Invention
`The present invention relates to a control apparatus
`for an engine.
`2. Discussion of Background
`FIG. 1 is a block diagram showing the construction
`of a typical fuel control apparatus for an engine wherein
`an air flow sensor (AFS) for detecting an intake air
`quantity is used. In FIG. 1, a reference numeral 1 desig
`nates an air cleaner, a numeral 2 a hot wire type AFS, a
`numeral 3 a throttle valve for controlling the intake air
`quantity to the engine, a numeral 4 a surge tank, a nu
`meral 5 an air intake manifold, a numeral 6 an air intake
`valve driven by a cam (not shown), and a numeral 7 a
`cylinder. Although FIG. 1 shows only a single cylinder
`for simplifying explanation, the engine is, in fact, consti
`tuted by a plurality of cylinders.
`A numeral 8 designates an injector attached to each
`of the cylinders and a numeral 9 an electronic control
`unit (hereinbelow, referred to as an ECU) which con
`trols the fuel injection quantity to the injector 8 so as to
`provide a predetermined air fuel ratio (A/F) with re
`25
`spect to air sucked into each of the cylinders. The ECU
`9 determines the fuel injection quantity on the basis of
`the output signals of the AFS 2, a crank angle sensor 10,
`a start switch 11 and an engine-cooling water tempera
`ture sensor 12, and controls the pulse width of the fuel
`injection pulse signal to be supplied to the injector 8 in
`synchronism with the signal of the crank angle sensor
`10. The crank angle sensor 10 may be of a well-known
`type of generating a rectangular waveform signal
`wherein it raises at the upper dead points (TDC) and
`falls at the lower dead points (BDC) with the revolution
`of the engine.
`'
`FIG. 2 is a block diagram for explaining in more
`detail the operation of the ECU 9.
`At a revolution speed detecting section 90, a revolu
`tion speed is obtained by measuring the period between
`adjacent TDCs of the rectangular waveform signal
`from the crank angle sensor 10. An averaged intake air
`quantity detecting section 9gb operates to obtain the
`average value of output signals from the AFS 2 by the
`adjacent TDCs of the rectangular waveform output
`signal of the crank angle sensor 10. A basic pulse width
`subcalculation section 9c calculates a basic pulse width
`by dividing the average value of intake air quantity
`output signal of the average intake air quantity detect
`50
`ing section 9b by the output indicating the number of
`revolutions of the revolution speed detecting section 9a.
`A warming-up correcting section 9d determines a
`correction coefficient in response to the temperature of
`cooling water to cool the engine, which is represented
`55
`by the output of the cooling water temperature sensor
`12. The basic pulse width obtained at the basic pulse
`width sub-calculation section 9c and the correction
`coefficient obtained at the. warming-up correcting‘sec
`tion 9d are added or multiplied at a correction value
`calculating section 9e to thereby obtain the pulse width
`for fuel injection.
`On the other hand, a starting pulse subcalculation
`section 9f calculates a starting pulse width on the basis
`of the detection signal of the water temperature sensor
`12. A switch 9g selects either the injection pulse width
`or the starting pulse width upon receiving the output
`signal of the start switch 11 which detects the starting of
`
`40
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`60
`
`65
`
`SUMMARY OF THE INVENTION
`It is an object of the present invention to provide a
`control apparatus for an engine which eliminates the
`reduction of the controllability caused by an error in the
`intake air quantity detecting means in a high load region
`in the engine, and is capable of performing a correct
`control even in a rapid acceleration state of the engine.
`The foregoing and other objects of the present inven
`tion have been attained by providing an engine control
`apparatus having an intake air quantity detecting means
`
`TOYOTA Ex. 1126, page 7
`Toyota v. Hagenbuch
`IPR2013-00638
`
`

`

`5,137,001
`3
`to detect an intake air quantity to an engine and a con
`trol means to control the engine in response to the out
`put of the intake air quantity detecting means, charac
`terized by comprising a load detecting means to detect
`a load to the engine, and a clip means to clip the output
`of the intake air quantity detecting means at a second
`value when a predetermined time has passed after the
`load of the engine has reached a ?rst value or higher.
`
`BRIEF DESCRIPTION OF DRAWINGS
`A more complete appreciation of the invention and
`many of the attendant advantages thereof will be
`readily obtained as the same becomes better understood
`by reference to the following detailed description when
`considered in connection with the accompanying draw
`ings, wherein:
`FIG. 1 is a block diagram showing the construction
`of a typical control apparatus for an engine;
`FIG. 2 is a block diagram showing the construction
`of a typical ECU used for the control apparatus;
`FIG. 3 is the output characteristic diagram of the
`AFS used for a typical control apparatus;
`FIG. 4 is a time chart showing the operation of the
`control apparatus according to the present invention;
`and
`FIG. 5 is a flow chart showing the operation of the
`control apparatus according to the present invention.
`
`10
`
`20
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`25
`
`4
`FIG. 4 is a time chart showing the waveforms of the
`major components of the engine in a case that the intake
`air quantity exceeds the maximum value at the time of
`rapid acceleration of the engine. FIG. 4a is the wave
`form of the crank angle signal. In FIG. 4d, the solid line
`E indicates a case that the throttle opening degree is
`suddenly made large. FIG. 4c shows that the negative
`pressure D in the surge tank 4 increases with an amount
`of air charged in the surge tank. At this moment, there
`takes place an overshoot in an air flow rate A detected
`by the AFS 2. The waveform of the overshoot corre
`sponds to that of the actual amount of intake air. The
`judgement as to how much amount of load is applied to
`the engine depends on the throttle opening degree E,
`and when a value of the load exceeds the level G at
`which the judgement of high load is made, the count
`ing-down of the count value F is effected each time of
`ignition at the clip control counter Cmax. Duririg the
`counting operation, the intake air quantity detected by
`the AFS 2 is continuously used as the intake air quan
`tity. When the count value F becomes 0, determination
`is made as to whether or not the detected air flow rate
`A exceeds the maximum value C (i.e. Amax). When the
`detected air flow rate exceeds the maximum value C,
`the detected air flow rate is clipped at the maximum
`value C.
`When a low load is applied to the engine, or the air
`flow rate A is lower than the maximum value C even
`when the value countedtby the counter is 0, the de
`tected air flow rate A is used. Accordingly, air flow rate
`indicated by the dotted line B in FIG. 4b is obtainable,
`and the fuel injection corresponding to the air flow rate
`can be attained: In the conventional control apparatus,
`on the other hand, the air flow rate is clipped immedi
`ately after the air ?ow rate exceeds maximum value C,
`whereby the fuel injection quantity does not correspond
`to the intake air quantity.
`In the above-mentioned embodiment, the judgement
`as to the high load is made depending on the throttle
`opening degree of the‘ throttle valve. However, the
`judgement may be determined by using a negative pres
`sure or a charging efficiency. Further, the counting
`down at the counter may be conducted each time of
`ignition. Further, the counting-down may be effected at
`constant time intervals.
`In FIG. 5, description is made as to use of the average
`value of the output of the AFS 2 between the TDCs. 0n
`the other hand, in FIG. 4, description is made as to use
`of the output of the AFS 2 directly. Thus, the effect of
`the present invention can be obtained by either of the
`cases.
`Obviously, numerous modifications and variations of
`the present invention are possible in light of the above
`teachings. It is therefore to be understood that within
`the scope of the appended claims, the invention may be
`practiced otherwise than as speci?cally described
`herein.
`What is claimed is:
`1. An engine control apparatus, comprising:
`intake air quantity detecting means for detecting an
`intake quantity of an engine;
`control means for controlling the engine in response
`to the output of the intake air quantity detecting
`means;
`load detecting means for detecting a load on the en
`gine; and
`clipping means for clipping the output of the intake
`air quantity detecting means at a second value
`
`30
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`35
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`40
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`45
`
`50
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENT
`A preferred embodiment of the control apparatus for
`an engine will be described with reference to the draw
`ings. The construction of the control apparatus of the
`present invention is the same as those shown in FIGS. 1
`and 2. Accordingly, the same reference numerals desig
`nate the same or corresponding parts.
`The operation of the control apparatus will be de
`scribed with reference to the flow chart shown in FIG.
`5.
`At step 101, an average air quantity A(n) between
`adjacent TDCs is obtained by dividing an accumulated
`air quantity S which is obtained in a constant time inter
`ruption routine (not shown in the drawings) _by the
`number of accumulations i, and then, the memory in a
`RAM which keeps the values S and i in the ECU is
`reset.
`At step 102, a determination is made whether or not
`there is a high load state, i.e. the load is at a predeter
`mined value or higher, by using a load parameter such
`as a throttle opening degree, a boost pressure or an
`other. When it is found that there is a low load, a prede
`termined value is set at a clip control counter Cmax at
`step 103. On the other hand, when a high load is found,
`determination is made at step 104 whether or not the
`value of the clip control counter Cmax is 0. When. the
`determination is negative, counting down is conducted
`in the clip control counter Cmax at step 105.
`On the other hand, when it is found that the value of
`the clip control counter Cmax is 0, the maximum value
`Amax of intake air quantity is read at step 106. The
`60
`maximum value Amax may be determined by using the
`revolution speed as a parameter and the maximum value
`is stored in a ROM in the ECU 9. _
`At step 107,- determination is made as to whether or
`not the average air quantity A(n) between the TDCs
`65
`exceeds the maximum value Amax. When the determi
`nation is affirmative, the value A(n) is set as Amax at ~
`step 108, whereby the clipping operation is effected.
`
`55
`
`TOYOTA Ex. 1126, page 8
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`

`5,137,001
`
`6
`clipping means for clipping the output of the intake
`air quantity detecting means at a second value
`when a predetermined time has passed after the .
`load of said engine has reached a ?rst value or
`higher, said ?rst value being greater than said sec
`ond value, and said ?rst value or higher represent
`ing said engine operating under a high load and
`said second value representing said engine operat
`ing under a relatively low load state, wherein said
`load detecting means detects and determines a load
`on said engine based on an output of said load
`detecting means being a predetermined value or
`higher; and
`means for setting an indicator when said engine is in
`said high load state, said clipping means operating
`' according to a presence or absence of said indica
`tor.
`5. The engine control apparatus according to claim 4,
`wherein the output of said intake air quantity detecting
`means is continuously supplied to said control means
`during said predetermined time after the load of said
`engine has reached said ?rst value or higher and before
`said output of said intake air quantity detecting means is
`clipped.
`'
`
`i i # $ l
`
`.
`
`_
`
`'5
`when a predetermined time has passed after the
`load of said engine has reached a ?rst value or
`higher, wherein the output of said intake air quan
`tity detecting means is continuously supplied to
`said control means during said predetermined time
`after the load of said engine has reached said ?rst
`value or ‘higher and before said output of said in
`take air quantity detecting means is clipped.
`2. The engine control apparatus according to claim 1,
`further comprising an air flow sensor, wherein the in
`take air quantity is obtained by averaging output values
`of said air flow sensor sampled with respect to a crank
`angle pulse signal.
`‘
`3. The engine control apparatus according to claim 1,
`further comprising a throttle value, wherein the load on
`the engine is determined depending on a throttle open~
`ing degree of the throttle valve.
`4. An engine control apparatus, comprising:
`intake air quantity detecting means for detecting an
`intake quantity of an engine;
`.
`control means for controlling the engine in response
`to the output of the intake air quantity detecting
`means;
`load detecting means for detecting a load on the en
`Zinc;
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`TOYOTA Ex. 1126, page 9
`Toyota v. Hagenbuch
`IPR2013-00638
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