JPS6183469A - Control device of throttle valve in engine - Google Patents

Abstract

PURPOSE:To promote the control of both the response characteristic and the stability, by obtaining a target throttle valve opening in accordance with an accelerator control quantity to be feedback controlled and decreasing a control constant when said accelerator control quantity is in a predetermined value or less. CONSTITUTION:A device, obtaining a target throttle valve opening theta1 or a target intake quantity AC1 in accordance with an accelerator control quantity alphawhile feedback controlling a throttle valve opening thetaR so as to obtain the target value, controls the opening of a throttle valve by a control signal theta2. Here the device, when the accelerator control quantity alpha is normally in a predetermined value or more, maintains a control constant K to a large level in a feedback control output from a control constant changing means 37, controlling the throttle valve in a good response characteristic. While the device, when the control quantity alpha is in the predetermined value or less, decreases a discriminative constant D of the feedback control to a small level, and the device, feedback correcting little by little the throttle valve opening and suppressing an intake quantity change to a small level, performs a feedback control in good stability.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a throttle crusher m+ device for an engine,
In particular, the throttle valve opening is fed back υ in order to achieve a predetermined intake air for the accelerator operation amount that indicates the required engine output.
I (Regarding the improvement of IO.

(Prior Art) Conventionally, as a technique for controlling the intake air amount supplied to the engine to a predetermined intake air amount in response to the accelerator operation amount indicating the required engine output, as shown in Japanese Patent Application Laid-Open No. 58-57039, an accelerator detection means for detecting an accelerator operation amount; and a target throttle that receives the output of the accelerator detection means and sets a target opening degree of a throttle valve so that the amount of intake air supplied to the engine becomes a target intake amount according to the accelerator operation amount. The device includes a valve opening degree setting means and a throttle valve driving means for driving the throttle valve to the target opening degree. There is a known system that performs feedback control on the throttle valve opening.Then, by supplying the amount of fuel to the engine so that the air-fuel ratio is set in advance according to the intake air m based on the throttle valve opening, The engine's air-fuel ratio is set to a target value.

(Problem to be Solved by the Invention) By the way, in order to improve the responsiveness in such feedback control of the throttle valve opening IQ', it is necessary to set the control constant governing the feedback direction to a large extent. preferable. However, if the control constant is set large, when the accelerator operation amount is small, that is, throttle valve 1;
When l a is small, there is a problem that the stability of the feedback control is impaired because the change in intake air is large relative to the change in the throttle valve opening due to the feedback control.

The present invention has been made in view of the above, and an object of the present invention is to adjust the control constant according to the accelerator operation amount when the throttle valve opening degree is feedback-controlled according to the accelerator operation amount as described above. The purpose is to achieve both responsiveness and stability in feedback control of the throttle valve by appropriately setting the values.

(Means for solving the problem) In order to achieve the above object, the solving means of the present invention, as shown in FIG. The throttle valve υItl of the engine is determined, and the throttle valve opening θR is feedback-controlled so as to reach the target value.
In addition, when the accelerator operation amount α is below a predetermined value, the ailj fit constant k in the feedback control of the throttle valve is
The control constant changing means 37 for reducing the .

(Function) With the above configuration, in the present invention, the control constant k in the feedback control of the throttle valve is maintained large during normal times when the accelerator operation amount α is equal to or higher than a predetermined value, and the feedback control of the throttle valve opening is performed with good responsiveness. It will be done. On the other hand, when the accelerator operation mα is less than a predetermined value, that is, when the throttle valve opening is small, the feedback control discrimination constant k becomes small, and the feedback correction of the throttle valve opening is performed in small increments. Changes are suppressed to a small extent, and feedback control is performed with good stability.

(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 4-cylinder engine, for example, 2 has one end connected to the atmosphere via an air cleaner 3, and the other end connected to the engine 1. An intake passage 4 opens to the engine 1 to supply intake air (air) to the engine 1, and an exhaust passage 4 has one end opening to the engine 1 and the other end opening to the atmosphere to discharge exhaust gas from the engine 1. Reference numeral 5 indicates an accelerator pedal that is depressed in response to the engine output request, and reference numeral 6 indicates a throttle valve that is disposed in the intake passage 2 and controls the intake air chamber. There is no linkage relationship, and as will be described later, it is electrically controlled by the amount of depression of the accelerator pedal 5, that is, the amount of accelerator operation. Reference numeral 7 denotes a throttle actuator comprising a step motor or the like that opens and closes the throttle valve 6. Reference numeral 8 denotes a catalyst device that is interposed in the exhaust passage 4 and purifies exhaust scum.

Further, 9 has one end opened upstream of the contact TR device 8 of the exhaust passage 4 and the other end opened downstream of the throttle valve 6 of the intake passage 2, so that a part of the exhaust gas in the exhaust passage 4 is returned to the intake passage 2. An exhaust gas recirculation passage 10 is interposed in the middle of the exhaust gas recirculation passage 9 to control the amount of exhaust gas recirculation. A recirculation control valve 11 is a solenoid valve that controls the opening and closing of the recirculation control valve 1o, which is a diaphragm device whose operating source is intake negative pressure.

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 fuel is supplied from the fuel tank 16, and the surplus fuel is returned to the fuel tank 16 through a return passage 18 with a fuel pressure regulator 17 interposed therebetween. Therefore, fuel at a predetermined pressure is supplied to the fuel injection valve 12.

In addition, 1 is an accelerator pedal position sensor as an accelerator detection means for detecting the amount of depression of the accelerator pedal 5, that is, the accelerator operation mα, and 20 is an accelerator pedal position sensor disposed upstream of the throttle valve 6 in the intake passage 2 to detect the intake air! An air flow meter that detects flQaR; 21 is an intake air temperature sensor that is also 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 the opening θR of the throttle valve 6; 23 is an air flow meter that detects flQaR; A water temperature sensor that detects the engine coolant temperature TW, 24 is an exhaust passage 4
02 sensor 25 which is arranged upstream of the catalyst device 8 and detects the air-fuel ratio λ of the engine 1 from the oxygen concentration component in the exhaust gas;
is a recirculation sensor that is attached to the recirculation control valve 10 and detects when exhaust gas is recirculated, and these detection signals 19 to 25 are sent to a control unit 2 comprising an analog computer or the like.
6, and the control unit 26 controls the throttle actuator 7 and the solenoid valve 11.
and the fuel injection valve 12 are controlled. Further, an igniter 27 is connected as an input to the control unit 26, and receives a signal indicating the number of ignitions, that is, the engine rotational speed Ne. Further, a dust distributor 28 and a battery 29 are connected as inputs to the control unit 26, and the ignition timing and battery voltage v are connected to each other.
8 signals are input.

Next, the operation of the control unit 26 will be explained with reference to FIG. Note that FIG. 3 shows the case of a four-cylinder engine.

In FIG. 3, first, the throttle valve opening level (MAI, to talk about the control system) is set to the target value Qa+ of air supplied to the engine 1 so that the air-fuel ratio is preset for the accelerator operator α. This is the first map that receives the output from the accelerator pedal position sensor 19 and sets the target air ff1Qa1 to be supplied to the engine 1 according to the accelerator operator α.
is a second map in which the minimum air @Qam is set to make the air-fuel ratio necessary for idle up with respect to the engine coolant temperature Tw, and it receives the output from the water temperature sensor 23 and calculates the engine coolant temperature Tw. The minimum air amount Qam for water temperature correction is set accordingly.

31 is the first map MAI and the second map M^2
, the maximum value Qa2 of the target air ff1Qa+ obtained from the first map MAL and the minimum air amount Q arn for water temperature correction obtained from the second map MA2 is determined.
This is a maximum value selection circuit that selects the target air amount Qa.
+ is less than the minimum air amount Qam for water temperature correction, the minimum air amount fQQam for water temperature correction is selected to increase the idle, thereby ensuring good engine operability. Further, MA3 is a third map in which a maximum air ffiQaM determined by the engine speed Ne is set with respect to the engine speed Ne.
I am trying to set QaM. 32 is the maximum of 1 above
Receives each output of the i111 selection circuit 31 and the third map MA3, and selects the minimum value Qa3 of the maximum air ff1Qa2 determined by the maximum 1ltI selection circuit 31 and the maximum air ff1QaM determined by the third map MA3. This is a small value selection circuit, and when the target air amount Qa1 exceeds the maximum air amount QaM determined by the engine rotation speed Ne, it is meaningless to set the target amount to be more than the amount of air that can be taken in when the throttle valve 6 is fully open. Therefore, by selecting the maximum air ffi Q a M and limiting the maximum value, a fully open signal corresponding to the fully open throttle valve 6 is output. As a result of the above, the accelerator operation amount α
, the target air amount Qa3 takes into consideration the correction for the engine coolant temperature Tw and the correction for the maximum air amount at all throttle valves 6 determined by the engine speed Ne.
is found.

Furthermore, 33 is a divider which receives the output from the minimum value selection circuit 32 and divides the target air eQa 1 by C'X (NOX2) which is the engine rotational speed Ne by 2a.
The intake air ff1Ac+ per cylinder in a cylinder engine is calculated. MA4 and MA5 are the throttle valve opening θ1 that should be the target intake air ff1Ac+ for the engine rotation speed Ne when exhaust gas recirculation is stopped and during exhaust gas recirculation, respectively.
or the fourth and fifth maps in which θ1ε is set, both maps MA4. MA5 receives the signal from the recirculation sensor 25 when exhaust recirculation is stopped and exhaust 3! ! The throttle valve opening θ1 or θIF is selected by a reflux switch 34, which is switched depending on the flow, and receives the output from the desensitizer 33 to set the target intake ff1Ac+. Further, 35 is an intake air amount feedback correction module, which receives the target intake air ff from the divider 33 as will be described in detail later.
In addition to receiving the signal of 1Ac+, the actual intake air per cylinder (6 ) AC
R and target intake air pressure Δc1 are compared to calculate a feedback correction coefficient Capa for feedback correcting the throttle valve opening according to the deviation. Further, 36 is the fourth or fifth map MA 4 ,
MA s and intake air amount feedback correction module 3
5, the map MA J , MA
A multiplier that corrects the target throttle valve opening θ1 or θIE obtained by s by the feedback correction coefficient CaFe obtained by the intake air amount feedback correction module 35, the target throttle valve opening corrected by the multiplier 36. The signal of degree θ2 is outputted to the throttle actuator 7, so that the opening degree of the throttle valve 6 is feedback-controlled to the target throttle valve opening degree θ2.

The operation of the intake air amount feedback correction module 35, which is a main component of the present invention, will be explained based on the flowchart of FIG. 4. First, in step S1, the actual intake air ff1AcR per cylinder is calculated from the actual air amount θaR and the engine rotational speed Ne by 1mE [Then, in step S2, the engine rotational speed Ne signal from the igniter 27 and the actual intake air from the throttle position sensor 22 are calculated. A control zone in feedback control of the throttle valve 6 is determined based on the throttle valve opening θR signal. This control zone determination is performed based on the control zone determination map shown in FIG. In other words, this Bit + control zone map shows the throttle valve opening θR between the unstable area 1g<A zone where the change in intake air amount due to the change in throttle valve opening θR is large and the stable area (B zone) where the change in intake air amount is small.
A boundary value is set for the engine speed Ne, and a control constant kIfi in feedback control of the throttle valve 6 is set in advance for each zone. In addition, the boundary value of the above-mentioned throttle valve opening 1 θR is determined from FIG. 6 when the intake air amount starts to converge toward a constant value when the engine speed is kept constant and the throttle valve opening θR is increased. It is determined by the value of the throttle valve opening θR.

Next, in step S3, it is determined whether the control zone is in the unstable region (A zone) or not (B zone).
When , the control constant k is set to 0.1% in step $4, and when YES in the unstable region (zone A), the control constant k is set to a small value of 0.5% in step S5. After that, in step $6, it is determined whether the target intake air amount Δc1 is larger than the actual air amount ACR, and if YES in Act>ACR, it is determined that the throttle valve 6 is insufficiently opened, and step S7 The feedback coefficient CaFs is C
a F 13 +, while ACt<ACR No.
In this case, it is determined that the throttle valve 6 is listening too much, and in step S8 the feedback coefficient CaFa is
: 8- and 10m5ec in step S9, respectively.
After waiting, the process returns to step S1. Here, in steps 82 to S5, the control constant k in the feedback control of the throttle valve 6 is set to be large when the throttle valve opening degree, that is, the accelerator operation amount α is greater than a predetermined value, and when the accelerator operation amount α is less than the predetermined value, the control constant k is set to a large value. le (1 circle constant k
It constitutes a control constant changing means 37 for changing the value to a smaller value.

Next, referring to the fuel supply amount control system shown in Fig. 3, in MB6, the target value Qr+ of the fuel supplied to the engine '1 is set so that the air-fuel ratio is set in advance in response to the accelerator operation mα. The sixth map receives the output from the accelerator pedal position sensor 19 and outputs the accelerator operation amount α (responsively, the target fuel 1f to be supplied to the engine 1).
fiQf1 is set. MB7 is the seventh map in which the minimum fuel ffiQfm for the engine coolant temperature Tw is set so that the air fuel ratio necessary for idle up is obtained for the air amount Qam set in the second map to 1A2. Based on the output of the water temperature sensor 23, the minimum fuel amount Qfm for water temperature correction is set in accordance with the engine cooling water temperature Tw. Three are the above 6th map Ms.
e and the outputs of the seventh map Mθ7, the maximum one of the target fuel ff1Qf+ determined by the sixth map Ms6 and the minimum fuel for water temperature correction jlQfm determined by the seventh map MBy (the maximum for selecting IQf2) is determined. It is a value selection circuit, and the target fuel amount Qf+ is the minimum fuel f for water temperature correction.
When the engine speed falls below iQfm, the minimum fuel Qfm for water temperature correction is selected to increase the idle to ensure good engine operability. Furthermore, MB2 is an eighth map in which the maximum fuel m Q f M for the engine speed Ne is set so that the maximum air ff1Qa M set in the third map MA3 becomes the preset target air-fuel ratio. Therefore, the maximum fuel mQf M is set according to the engine speed Ne. 40 receives the respective outputs of the maximum value selection circuit 39 and the eighth map MBg, and selects the maximum fuel 111ftQf2 obtained by the three maximum value selection circuits and the eighth map MBg.
This is a minimum value selection circuit that selects the minimum value Qf3 of the maximum fuel mQfM determined by the map Mea, and when the target fuel rf#Qf1 exceeds the maximum fuel mQfM determined by the engine speed Ne, that is, as described above. When the target air IQa+ exceeds the maximum air ffiQaM determined by the engine speed Ne, and the target value is greater than the amount of air that can be taken in when the throttle valve 6 is fully open, the maximum air ffiQaM is selected and the maximum fuel 11QfM is selected, and the target value Qf+ is corrected so that the air-fuel ratio becomes a preset target air-fuel ratio for the amount of intake air supplied to the engine 1. As described above, as in the case of the air amount, the target fuel for the accelerator operation amount α takes into account the correction for the engine cooling water temperature Tw and the correction for the maximum fuel amount when the throttle valve 6 is fully open determined by the engine rotation speed Ne. ff1Qf3 is found.

Then, the target fuel amount Qf from the maximum value selection circuit 40 is
3 (g@ stands for the derailer 41, the first to third derailers 42 to 44
, 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 40, and divides the target fuel faQf3 by the engine rotational speed Ne assuming that fuel is injected into two cylinders at the same time to calculate fuel supply 1Qfi per cylinder. It is something. In addition, the first
The multiplier 42 converts the target fuel supply 81 supply m Q f i obtained by the divider 41 into the ° water temperature correction tM error CTW for the engine cooling water temperature lower W obtained from the ninth map M89.
and target fuel supply m after correcting the enrichment correction coefficient CER″c-th power σ determined by the enrichment correction module 47.
This excludes Q f i +. The enrichment correction module 47 uses an enrichment correction coefficient CER to increase the fuel supply amount by, for example, 8% when the intake air ff1Ac+ relative to the engine speed Ne is in the enrichment line region based on a zone signal from a zone determination module 51 to be described later. (For example, it outputs 1.08>.

Further, the second multiplier 43 converts the target fuel supply Jfi Q f i + obtained by the first multiplier 42 into the learning correction coefficient C5v obtained by the fuel learning correction module 48.
The target fuel supply ff1Qfi2 is calculated by OR multiplication correction. This fuel learning correction module 48 determines the fuel feedback correction conditions for the four fuel feedback correction modules based on the zone signal from the zone determination module 51 and the fuel feedback correction coefficient Cf FB multiplication signal from the four fuel feedback correction modules described below. For example, if more than 2 seconds have passed after the establishment of the fuel learning correction staff! &Cs T D is set to its initial value -1, 0, and then sequentially updated and output using the following formula % (peak value of Cfpa + bottom value of CrF2 of the past 8 times)/16-1.01. be.

Further, the third multiplier 44 multiplies and corrects the target fuel supply machine Q'12 obtained by the second multiplier 43 using the fuel feedback correction coefficient CfFs obtained by the four fuel feedback correction modules. target fuel supply +1Qfi
3 is calculated. The fuel feedback correction module 49 calculates the following conditions based on the zone signal from the zone determination module 51 and the air-fuel ratio λ signal from the 02 sensor 24.
ct≧10% of cylinder stroke volume ■ Engine speed N
When the intake air ff1Ac+ for e is outside the enrich line and the tunnel cut zone ■02 sensor 24 is active, the fuel feedback correction coefficient Cf1 day is set to feedback control the fuel supply m <For example, 0.8
≦CfFB≦1.25, the proportional constant P=0.06, and the integral constant [-0.05/sec) are output.

Further, the twin cut switch 45 is switched to 61 by an output signal from the twin cut control module 50.
It is quietly controlled. This Tsuyunilcut iI++
The Ut+ module 50 is a zone determination module 51
Based on the zone signal and target intake air amount Act signal from
0℃ ■ Intake ff1Ac+<10% of cylinder stroke volume■
When the engine speed Ne>1000r+on is satisfied,
In order to cut fuel injection, the unit control switch 45 is opened. Here, the zone determination module 51 determines the engine rotation speed Ne, the target intake f.
f1Ac+, engine cooling water temperature T'w, and air-fuel ratio λ, the control modules 47 to 5
A condition determination signal (zone signal) of 0 is created.

Additionally, the fuel injection valve correction circuit 46 is configured to
Upon receiving the target fuel supply ff1Qfit signal from the multiplier 44 and the battery voltage Va signal from the battery 29, the pulse signal as the target fuel supply amount signal to the fuel injection valve 12 is corrected according to the battery voltage v8, and the fuel injection valve 12
This is what is output to. As described above, the fuel injection valve 12
is driven for a predetermined period of time in synchronization with ignition, and the amount of fuel supplied is controlled to a target value.

Therefore, in the above embodiment, the accelerator operation amount α
The target air amount to be supplied to the engine 1 is determined according to
A target opening degree of the throttle valve 6 is determined based on this target air amount, and the opening of the throttle valve 6 is feedback-controlled so as to reach this target opening degree, and the target intake air amount is supplied to the engine 1. At this time, when the intake air amount feedback correction module 35 determines that the engine 1 is in the unstable gA region, the throttle valve opening is corrected to increase or decrease in small increments by setting a small control constant k in the feedback control of the throttle valve 6. Since the change in the intake air m becomes small, feedback control of the throttle valve 6 can be performed with good stability. Furthermore, since the control constant k is set large in the stable region of the engine 1, good responsiveness of the feedback control can also be ensured.

Also, the target air amount 17'l and the target fuel amount are respectively determined for the accelerator operating finger α, and the intake air amount and fuel supply amount are set to the target values simultaneously and in parallel based on the determined target values. By being controlled so that
Since the intake air amount and the fuel supply amount change to the target value at the same time without any time lag in response to a change in the accelerator operation amount α, irregularities in fuel response do not occur even during transient operation of the engine. Therefore, the air-fuel ratio of the engine can be precisely controlled to the target air-fuel ratio, and the acceleration performance and driving performance of the engine can be improved without causing problems such as engine failure or misfire as in the conventional case. Moreover, since the intake air amount and fuel supply amount are simultaneously controlled to a preset air-fuel ratio in response to the accelerator operation amount α,
Accurately achieves target air-fuel ratio without requiring feedback efficiency
i, +]olI, thus simplifying the control. In the above embodiment, the control constant changing means 37 is controlled more and more as the engine reaches a low rotational speed range and a low intake air temperature. I changed the constant k to be smaller, but
The gear position may be detected as the operating state of the engine, and the aill III constant k may be made smaller as the gear becomes lower. This produces the same effect as the above embodiment.

Furthermore, in the above embodiment, the target air amount is first determined according to the accelerator operation amount, and then the target throttle valve opening degree is determined based on this target air direction, and the throttle valve 6 is adjusted so that the target throttle valve opening is achieved. Although this application was applied to a feedback control system, it is also applicable to other systems that directly determine the target throttle valve opening or target air direction according to the amount of accelerator operation and feedback control the throttle valve to reach the target value. It is equally applicable.

(Effects of the Invention) As explained above, according to the present invention, when the accelerator operation direction is less than a predetermined value, that is, when the opening degree of the throttle valve is small, the throttle valve feedback control
Since l+ control constant becomes small, feedback control can be performed with good stability.

Moreover, since the control constant is set large when the accelerator operation amount is equal to or greater than the predetermined shift, the throttle valve feedback control can be performed with good responsiveness, and therefore the responsiveness and stability of the throttle valve feedback control can be improved. It is important to try to balance both.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention. 2 to 6 show embodiments of the present invention, FIG. 2 is a general schematic diagram, FIG. 3 is a block diagram showing the operation flow of the control unit, and FIG. 4 is the operation of the intake air amount feedback correction module. FIG. 5 is a flowchart showing the flow, FIG. 5 is a diagram showing a control zone discrimination map, and FIG. 6 is a characteristic diagram showing the characteristics of the throttle operation amount with respect to the intake air amount. 1...Engine, 5...Accelerator pedal, 6...
Throttle valve, 7... Throttle actuator, 1
9...Accelerator pedal position sensor, 20...
Air 70-meter, 22... Throttle position sensor, 26... Control unit, 27... Igniter, 35... Intake air amount feedback correction module, 37... Control constant changing means. Figure 5 Engine rotation speed (rpm) Figure 6 QJffi@ (rn3/h) Figure 4

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 the accelerator operation amount and performs feedback control of the throttle valve opening so that the target value is achieved, the accelerator operation 1. A throttle valve control device for an engine, comprising control constant changing means for reducing a control constant in feedback control of the throttle valve when the amount is less than a predetermined value.