JPS6185551A - Controller for throttle valve of engine - Google Patents

Abstract

PURPOSE:To enhance safety, by providing a means for setting an upper limit value to compensation in the feedback control of a throttle valve, to prevent uncontrolled operation at the time of defectiveness of a sensor. CONSTITUTION:An aimed throttle valve opening degree theta1 or an aimed intake quantity Ac1 is determined depending on the operated quantity alpha of an accelerator. The degree thetaR of opening of a throttle valve is feedback-controlled to be equal to the aimed opening degree theta1. A means 37 for setting an upper limit value Camax to compensation in the feedback control of the throttle valve is provided. When a compensated value in the feedback control of the throttle valve exceeds the upper limit value Camax, the feedback compensation is stopped. Uncontrolled operation at the time of defectiveness of a sensor for detecting the degree of opening of the throttle valve or the quantity of intake is thus prevented to enhance safety.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to the left hand of the throttle of an engine. This invention relates to an improvement in a feedback system tIl'Tj.

(Prior Art) Conventionally, as a technique for controlling the amount of intake air supplied to the engine to a predetermined amount for an accelerator operator who indicates a required engine output, as shown in Japanese Patent Laid-Open No. 58-57039, an accelerator detection means for detecting an operator;
a target throttle valve opening setting means for receiving the output of the accelerator detecting means and setting a target opening of a throttle valve so that the amount of intake air supplied to the engine in response to the accelerator operation M becomes a target intake amount; and the target opening. There is a known device which is equipped with a throttle valve driving means for driving the throttle valve, determines a target throttle opening according to the accelerator operator, and feedback-controls the opening of the throttle valve so as to reach the target opening. It is being Then, the air-fuel ratio of the engine is set to the target value by supplying the amount of fuel to the engine so that the air-fuel ratio is set in advance according to the intake air amount based on the opening of the throttle valve. Note that instead of determining the target throttle valve opening as described above, a target value of the intake air amount to be supplied to the engine is determined according to the accelerator operation amount, and the throttle valve opening is feedback-controlled so as to reach the target intake air amount. This is also possible and is equivalent to the above.

(Problems to be Solved by the Invention) By the way, the target throttle valve degree Un or the target intake air amount is determined based on the output of the sensor that detects the opening of the throttle valve or the sensor that detects the amount of intake air supplied to the engine. When feedback controlling the throttle valve opening so that This may result in the vehicle running out of control, so fail-safe measures are required in such cases.

Therefore, the present invention has been made in view of this point, and its purpose is to set an upper limit on the correction value in the feedback hr control of the throttle valve as a fail-safe measure as described above, and to set an upper limit on the correction value in the feedback hr control of the throttle valve. When the value exceeds the value, it is determined that the sensor that detects the throttle valve opening or the intake amount has failed, and feedback correction of the throttle valve opening is stopped, thereby preventing runaway in the event of a failure of the sensor. The purpose is to improve safety.

(Means for solving the problem) In order to achieve the above object, the solving means of the present invention is as follows:
As shown in the figure, the target throttle valve opening θ1 or target intake air ff1Ac+ is determined according to α during accelerator operation,
In an engine throttle valve 1Iill M device that performs feedback control of the opening degree θR of the throttle valve so as to reach the target (1t1), the correction upper limit 1iaCaIll in the feedback control of the throttle valve is
A correction rfi value setting means 37 for setting ax is provided.

(Function) With the above configuration, in the present invention, when feedback control is performed to make the opening degree θR of the throttle valve to the target opening degree θ1 or the target intake air ff1Ac+ according to the accelerator operation interval α, the feedback IQ control of the throttle valve is performed. Whenever the correction value exceeds the correction upper limit value CallaX set by the correction upper limit value setting means 37, the feedback correction of the throttle opening degree is stopped. Therefore, the divergence of the throttle valve's 17i1 degree due to a failure of the sensor that detects the throttle valve opening degree or the sensor that detects the intake air amount is suppressed, and runaway in the event of a failure of the sensor is prevented. be.

(Example) Hereinafter, an example of the present invention will be described based on the drawings from FIG. 2 onwards.

FIG. 2 shows the overall configuration of an engine throttle valve control device according to an embodiment of the present invention, where 1 is a four-cylinder engine, for example, one end is open to the atmosphere via an air cleaner 3, and the other end is connected to the engine 1. An intake passage opens to supply intake air (air) to the engine 1, and 4 is an exhaust passage whose one end opens to the engine 1 and the other end opens to the atmosphere and discharges exhaust gas from the engine 1. The accelerator pedal is depressed in response to an output request, and the throttle valve 6 is disposed in the intake passage 2 and controls the intake air chamber.The throttle valve 6 has a mechanical linkage relationship with the accelerator pedal 5. As mentioned above, when the accelerator pedal 5 is depressed M, that is, during the accelerator operation, it is electrically t++1 tilled.

Reference numeral 7 denotes a throttle actuator comprising a step motor or the like that opens and closes the throttle valve 6 . 8 is a catalyst v4 installed in the exhaust passage 4 for purifying exhaust gas.

Further, reference numeral 9 has one end open to the catalyst device 8-[flow of the exhaust passage 4 and the other end opened downstream of the throttle valve 6 of the intake passage 2, so that part of the exhaust gas in the exhaust passage 4 is transferred to the intake passage 2. An exhaust gas recirculation passage 10 for recirculating is interposed in the middle of the exhaust gas recirculation passage 9, and passes through the exhaust gas flow m. The recirculation control valve 11 is a solenoid valve that controls the opening and closing of the internal flow control valve 10.

On the other hand, reference numeral 12 denotes a fuel injection valve disposed downstream of the throttle valve 6 in the intake passage 2 to inject and supply fuel. The fuel tank 16 is connected to the fuel tank 16 through the fuel tank 16, and the fuel is supplied from the fuel tank 16, and the remainder f! II fuel is fuel pressure regulator 1
Fuel tank 16 via return passage 18 with 7 interposed
Therefore, fuel at a predetermined pressure is supplied to the fuel injection valve 12.

In addition, 19 is an accelerator pedal position sensor that detects the depression m of the accelerator pedal 5, that is, the accelerator operation amount α; 20 is an air flow meter that is disposed upstream of the throttle valve 6 in the intake passage 2 and detects the intake air amount QaR;
21 is the same (intake air temperature sensor arranged upstream of the throttle valve 6 in the intake passage 2 and detects the intake air temperature, 22 is a throttle position sensor that detects fKJ IQθR of the throttle valve 6, and 23 is the engine cooling water temperature TW) The water temperature sensor 24 detects the catalyst device t!28 in the exhaust passage 4.
02 sensor is disposed upstream and detects the desirable fuel-fuel ratio λ of the engine 1 from the @element clearance component in the exhaust gas; The detection signals 19 to 25 are inputted to a control unit 26 consisting of an analog computer or the like, and the control unit 26 controls the thrower 1 actuator unit, solenoid valve 11, and fuel injection valve 12. . Further, an igniter 27 is input connected to the control unit 26, and inputs the number of ignitions, that is, the engine rotational speed (N e Q). In addition, the control unit 26
A dust distributor 28 and two batteries are connected as inputs, and input signals of ignition timing and battery voltage VB, respectively.

Next, the operation of the control unit 26 is performed as shown in FIG. Note that FIG. 3 shows the case of a four-cylinder engine.

In FIG. 3, first, the throttle valve opening degree i control system will be described. This is the first map that receives the output from the accelerator pedal position sensor 19 and sets the target air ff1Qa to be supplied to the engine 1 according to the accelerator operation amount α. :t/71 water)Ω(IJ Tw A second map in which the minimum air amount Qam is set to make the air-fuel ratio necessary for idle up, and receives the output from the water temperature sensor 23. Engine coolant temperature Tw
The minimum air temperature for water temperature correction fi Q all is set accordingly.

31 is the first map MAL and the second map MA2.
This is a maximum value selection circuit which receives each output and selects the maximum value Qa2 of the target air ff1Qa+ obtained from the first map MAL and the minimum air amount Qam for water temperature correction obtained from the second map MA2. , -E target air direction Qa
When + is less than the minimum air amount Qam for water temperature correction, the minimum air amount fflQam for water temperature correction is selected to increase the idle, thereby ensuring good engine operability. Further, 3 to M is a third map in which the maximum air ff1QaM determined by the engine speed Ne is set for the engine speed Ne, and receives the output from the igniter 27 and maximum air ffi
I am trying to set QaM. 32 receives each output of the maximum value selection circuit 31 and the third map MA3;
Maximum air ff1 determined by maximum 11ft selection circuit 31
Qa, and the maximum air fl obtained from the third map MA3
This is a minimum value selection circuit that selects the minimum value Qa3 of QaM, and the target air amount Qa1 is the engine rotation speed N.
When the maximum air direction QaH determined by 13 is exceeded,
Since it is meaningless to set the target value to be more than the amount of air that can be sucked in when the throttle valve 6 is fully open, the maximum air f
By selecting f1QaM and limiting the maximum value 1n, a full open signal corresponding to the throttle valve 6 being fully opened is output. As described above, the target air amount Qaz is determined for the accelerator operation amount α by reconsidering the correction for the engine coolant temperature Tw and the correction for the maximum air direction at the throttle valve 6, which is determined by the engine rotation speed No.

Further, 33 receives the output from the minimum value selection circuit 32, sets the target air mQa3 to 2, and sets the engine speed Ne to 2.
A divider that divides by the multiplied value (NOX2) calculates the intake mAcI per cylinder in a 4-cylinder engine. M.A.
4 and 5 to M are the target intake air amount A for the engine rotation speed No when exhaust gas recirculation is stopped and during exhaust gas recirculation, respectively.
c+ and the fourth and fifth maps in which the valve opening degree θl or θIE are set, and both maps MA
4. The MAS detects IJ by the signal from the reflux sensor 25.
Reflux switch 3 which switches between F-air recirculation stop and exhaust recirculation
4, receives the output from the divider 33, and selects the throttle valve opening θ which should be the target intake air ff1Ac+.
1 or θ1E. Further, 35 is an intake air amount feedback correction module which receives the signal of the target intake air amount AC+ from the divider 33 as described in detail in the figure, and also receives the signal of the target intake air amount AC+ from the divider 33 and calculates the actual air mQaR and engine speed Ne actually measured by the air flow meter 20. After receiving the signal, the actual intake air per cylinder 11Ac R and the target intake f are arranged based on the actual air ff1QaR and the engine speed Ne.
Compare f1Ac+ and adjust the throttle valve according to the deviation! A feedback correction coefficient CaFe for feedback correction of l is calculated. Furthermore, 3
6 receives each output from the fourth or 57th knob MA 41 MA s and the intake air amount feedback correction module 35, and outputs the map MA4. A multiplier that corrects the target throttle valve opening θ1 or θIE obtained by MAS with a feedback correction coefficient Caps obtained by an intake air amount feedback correction module 35, the target throttle valve corrected by the multiplier 36. The signal of the opening degree θ2 is output to the throttle actuator 7, so that the opening degree of the throttle valve 6 is fed back to the target throttle valve opening degree θ2 by $1111-.

As a main component of the present invention, the intake air amount feedback correction module 35 operates based on the flowchart shown in FIG. That is, in FIG. 4, first, in step sI, the signals of the actual air ff1QaR from the air flow meter 20 and the engine rotational speed N13 from the igniter 27 are inputted, and the actual air mQa is inputted.
Divide R by twice the engine speed Ne,
After calculating the actual intake air ff1AcR per cylinder, the target intake air ff1Ac+ and the actual intake air amount AJR are compared in magnitude in step S2. When Act>ΔOR is YES, it is determined that the throttle valve opening degree θR is being increased by correction of feedback control, and step S3
The feedback correction coefficient CaFB at that time is the correction lower limit value C in a3 for feedback control of the throttle valve 6.
Determine whether it is smaller than amax and ca F e
<Camax's Y E S (1),! : Ki1.
: ), t It is determined that the correction by feedback control is normal, and in step S4, the value obtained by adding the feedback correction coefficient CaF3 and 0.1% to it <= CaFB
+0.1%), and in step S5, return to step S+.On the other hand, when CaFB/Camax is NO, it is determined that the correction by the feedback control is abnormal due to a failure of the air flow meter 20. Then, step S is performed immediately without increasing the feedback correction coefficient CaFB in step S4.
Proceeding to step 5, further feedback correction of the throttle valve opening θR is stopped.

On the other hand, if the determination in step S2 is that ACI≦AC
When R is No, it is determined that the throttle valve opening θR is being decreased by correction of feedback control, and
In step S6, the feedback correction coefficient Ca at that time is
It is determined whether Fe is larger than a correction lower limit value Cam1n in feedback control of the throttle valve 6, and Ca
When F8>Cam1n is YES, it is determined that the correction by feedback control is normal, and in step S7 the feedback correction coefficient Caps is set to 0.
The value is updated to the value obtained by subtracting ゜1% (-CaFa-0,1%), and after 10m5ec\i machine is incremented in step S5, the process returns to step S1. On the other hand, N of CaFs≦Cam1n.

In this case, it is determined that the correction by the feedback control is also abnormal due to a failure of the air flow meter 20, and the feedback correction coefficient Ca in step S7 is determined to be abnormal.
The process immediately proceeds to step S5 without updating Fe to stop the feedback correction of the throttle valve opening θR below that.

.: Now, in step S3, the correction upper limit 1aca in the feedback νjtilI of the throttle valve 6 is
The correction upper limit (lt1 setting means 37 is configured to set maX).

Next, to describe the fuel supply amount control system in FIG. 6 map, which receives the output from the accelerator pedal position sensor 19 and supplies the target fuel mQf+ to the engine 1 according to the accelerator operation amount α.
I am trying to set it. MB7 is the second map M above.
This is the seventh map in which the minimum fuel ffI Q fn is set for the engine cooling water temperature Tw so that the air-fuel ratio is required for idle up with respect to the air 1Qara set in A2, and the map is based on the output of the water temperature sensor 23. For water temperature correction according to the engine coolant temperature Tw! low fuel fl
Set Qfm. 39 receives the respective outputs of the sixth map MB6 and the seventh map May, and outputs the sixth map M86.
The target fuel ff1Qf + obtained by and the seventh map M
A maximum value selection circuit that selects the maximum value Qf2 of the minimum fuel for water temperature correction fiQfm obtained in B7,
The above target fuel amount Qf+ is the minimum fuel amount fiQfm for water temperature correction.
When the engine speed exceeds the minimum fuel consumption, the lowest fuel level Qfm for water temperature correction is selected to increase the idle, thereby ensuring good engine operability. Also, Msa is the third map MA above.
This map is an eighth map in which the maximum fuel mQf M for the engine speed Ne is set so that the maximum air ff1Qa M set in No. 3 becomes a preset target air-fuel ratio, and Maximum fuel ff1Qf
Set M. 40 receives each output of the maximum value selection circuit 39 and the eighth map Msa, and selects the maximum (maximum fuel 1iar 2 determined by the 0 selection circuit 39 and the eighth map Msa).
This is a minimum value selection circuit that selects the minimum value Of3 from the maximum fuel ff1QfM determined by ss, and when the target twist F4ffiQfl exceeds the maximum fuel amount QfM determined by the engine speed Ne, In other words, as mentioned above, the target air ff1Qa + is the engine speed N
When the target value exceeds the maximum air amount ff1QaM determined by e and is greater than or equal to the amount of air that can be taken in when the throttle valve 6 is fully open, the maximum air mQaM and the maximum fuel ffiQfM are selected and the engine 1 The above-mentioned eA value Qf+ is corrected so that it becomes a preset target air-fuel ratio for the amount of intake air supplied to the engine. As described above, as in the case of the air amount, the accelerator operation amount α is corrected for the engine cooling water m a T w and the maximum fuel amount for all the throttle valves 6 determined by the engine rotation speed t%Je. Target fuel ff1 considered
Qf3 is found.

Then, the target fuel amount Qf from the maximum value selection circuit 40 is
The three signals are a divider 41, first to third multipliers 42 to 44,
It is output to the fuel injector 12 via the power switch 45 and the fuel injector correction circuit 46. The divider 41 receives the output from the minimum value selection circuit 4o, and divides the target fuel amount Qf3 by the engine rotational speed Ne assuming that fuel is injected into two cylinders at a time, and calculates the fuel supply per cylinder ffl Q fl @ n It's something that comes out. In addition, the first power tlX2s42 is calculated by converting the target fuel supply ff1Qfi obtained by the degassing device 41 into a water temperature correction coefficient CT for the engine cooling water temperature Tw obtained by the ninth map Mss.
The target fuel supply jlQfi+ is calculated by multiplying W and the enrichment correction coefficient CERI' obtained by the enrichment correction module 47. This enrichment correction module 47 is a zone determination module 51 which will be described later.
Based on the zone signal from the intake air ff1. When Ac+ is in the enrichment line region, an enrichment correction coefficient CER (for example, 1.08) is output in order to increase the fuel supply ω by, for example, 8%.

Further, the second multiplier 43 multiplies and corrects the target fuel supply ff1Qfi+ obtained by the first multiplier 42 by the learning correction coefficient C3TD obtained by the fuel shape correction module 48 to obtain the target fuel supply ff1Qri2. It is something to be released. This fuel learning correction module 48 determines the fuel feedback correction conditions in the fuel feedback correction module 49 based on the zone signal from the zone determination module 51 and the fuel feedback correction coefficient Crt=6 signal from four fuel feedback correction modules (described later). For example, when 2 seconds or more have elapsed after the establishment of , if the fuel learning correction coefficient C3 is set to the initial 1st shift = 1.0, then the following formula % peak value of CfFe + past 8 Cf rB ( 7) The bottom f1rl)/16-1.0) is sequentially updated and output.

Further, the third multiplier 44 multiplies and corrects the target fuel supply direction Q[12 obtained by the second multiplier 43 by the fuel feedback correction coefficient CtfFB obtained by the fuel feedback correction module 49 to obtain the target fuel supply direction Q[12]. Supply m Q f
This is b to calculate i 3. This fuel feedback correction module 49 receives the zone signal from the zone determination module 51 and the air-fuel ratio 21 from the O2 sensor height 24.
Based on item g, for example, the following conditions ■ Engine cooling water temperature Tw>60℃ ■ Intake ff1Ac+ ≧10% of cylinder stroke volume■
When the intake air ff1Ac+ with respect to the engine rotation @Ne is outside the enrich line and the tunnel cut zone. ■ When the 02 sensor 24 is active, the fuel feedback correction coefficient CfF8 (for example, Lfo,
8≦(j t: e ≦1°25, ratio measurement tl P=
0.06, integral constant 1-0.05/sec).

In general, the twin cut switch 45 is controlled to open and close by an output signal from the twin cut control module 50. This twin air cut control module 50 is affected by the zone signal and target intake air amount Act signal from the zone determination module 51, for example, under the following conditions: ■ Engine cooling water temperature Tw>60°C ■ Intake air ff1Ac+<10% of cylinder stroke volume■
When the engine rotational speed Ne>11000 rD is satisfied, control is performed to open the twin unit cutter switch 45 to cut off fuel injection. Here, the zone determination module 51 determines the engine rotation speed Ne, the target intake f.
ftAc+, the engine cooling water temperature Tw, and the air-fuel ratio λ.
7 to 50 condition determination signals (zone signals) are created.

Furthermore, the fuel injection valve correction circuit 46 includes the third fuel injection valve correction circuit 46.
Receives the target fuel supply mQf13 signal from the q multiplier 44 and the battery voltage VB signal from the battery 29, corrects the pulse signal as the target fuel supply amount signal to the fuel injection valve 12 according to the battery voltage Va, and performs fuel injection. It outputs to the valve 12. As described above, the fuel injection valve 12 is driven for a predetermined period of time in synchronization with ignition, and the fuel supply m is adjusted to the target value i1i'1rIO.

Therefore, in the above embodiment, the accelerator operation amount α
The target air m to be supplied to the engine 1 is determined according to
The target opening degree of the throttle valve 6 is determined based on this target air amount, and the opening degree of the throttle valve 6 is feedback-controlled 11 so as to reach the target opening degree, and the target intake air amount is supplied to the engine 1. At this time, since the correction value in the feedback control of the throttle valve 6 is set to the upper limit value CarAax by the correction upper limit fa setting means 37, the feedback correction exceeding the correction upper limit 1+tlcamax is not performed, and the air flow meter 20 is damaged. This prevents the throttle valve opening from diverging instead of converging, thereby making it possible to reliably prevent the vehicle from running out of control when the air flow meter 20 fails. In addition, since a correction lower limit 1flcamin is also provided for the feedback section 1 of the throttle valve 6, the feedback correction below the correction lower limit Ca...10 is not made, and the throttle valve is set to the minimum opening when the air flow meter 20 fails. It is possible to maintain the minimum number of vehicles running.

In addition, the target air amount and target fuel amount are respectively determined for the accelerator operation amount α, and based on the determined target 1m, the intake air amount and fuel supply amount are set simultaneously and in parallel to the target 1a. By being controlled by The engine air-fuel ratio can be accurately controlled to the target air-fuel ratio without causing delays in fuel response, and as a result, the engine's acceleration and driving performance are improved without the engine breathing or misfires that are conventional. can be improved. Moreover, the intake air amount and the fuel f1 supply m are simultaneously controlled to a preset air-fuel ratio with respect to the accelerator operation amount α.
Therefore, it is possible to control the target air-fuel ratio with good fR without requiring feedback control, and it is therefore possible to commercialize ill (2).

In the above embodiment, the target air amount is first determined according to the accelerator operation amount, and then the target throttle valve opening is determined based on this target air amount, and the throttle valve is adjusted so as to reach the target throttle valve opening. 6 has been applied to a system that uses feedback control, but there are other systems that directly determine the target throttle valve opening or target air m according to the amount of accelerator operation, and feedback control the throttle valve so that the desired value is reached. It is similarly applicable to .

Then, if the throttle valve feedback is based on the target throttle valve opening, the throttle position sensor 2 detects the throttle valve opening.
It is possible to take fail-safe measures (preventing the vehicle from running out of control) in the event of the failure of item 2.

(Effects of the Invention) As explained above, according to the present invention, when the opening degree of the throttle valve is fed back to the target opening or the target intake air amount υ3011 according to the accelerator operation amount, the feedback control of the throttle valve is Since the correction upper limit (C) is provided, it is possible to prevent the throttle valve opening from diverging when a sensor that detects the throttle valve opening or intake amount fails, and to prevent the vehicle from running out of control when the sensor fails. This can be reliably prevented and safety can be improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the present invention. Figs. 2 to 4 show embodiments of the present invention, Fig. fX52 is a general schematic diagram, Fig. 3 is a block diagram showing the operation flow of the control unit, and Fig. 4 shows the operation of the intake air amount feedback correction module. FIG. 1...Engine, 5...Accelerator pedal, 6...
Throttle valve, 7... Throttle actuator,
19...Accelerator pedal position sensor, 20...
・Air flow make, 22... Throttle position sensor, 26... Control unit, 35...
Intake air amount feedback correction module, 37...Correction upper limit In setting means.

Claims (1)

[Claims] (1) In an engine throttle valve control device that determines a target throttle valve opening or a target intake amount according to an accelerator operation amount, and performs feedback control of the throttle valve opening so that the target value is achieved, the throttle valve A throttle valve control device for an engine, comprising a correction upper limit value setting means for setting a correction upper limit value in valve feedback control.