JPS6183470A - Control device of throttle valve in engine - Google Patents

Abstract

PURPOSE:To prevent a torque shock while ensuring a good response characteristic, by changing a control constant in accordance with the operational condition of an engine when a throttle valve is feedback controlled in accordance with an accelerator control quantity. CONSTITUTION:When an opening thetaR of a throttle valve is feedback controlled so as to obtain a target opening theta1 or a target intake quantity AC1 in accordance with an accelerator control quantity alpha, a control constant K in a feedback control is changed by a control constant changing means 37 in accordance with the operational condition of an engine detected by a detecting means 20, 27. In this way, a response characteristic of the feedback control is ensured by setting the control constant K to a large value when the engine is in normal operation. While the control constant K is decreased to a small value when the engine is driven in low speed and low intake quantity operation or in low speed gear shift operation, and a torque shock is prevented by decreasing as small as possible a change quantity of intake for the change of opening of the throttle valve.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to throttle valve control ll1n of an engine, and in particular, feedback of the throttle valve opening to obtain a predetermined intake air amount with respect to an accelerator operation amount indicating a required engine output. Concerning improvements to things that are controlled.

(Prior Art) Conventionally, as a technique for controlling the amount of intake air supplied to the engine to a predetermined amount in response to the amount of accelerator operation indicating the required engine output, as shown in Japanese Patent Application Laid-Open No. 58-57039, an accelerator detection means for detecting an operation position;
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 becomes a target intake amount according to the amount of accelerator operation; and the target opening. There is a known device which is equipped with a throttle valve drive means for driving a throttle valve, determines a target throttle opening in response to accelerator operation, and performs feedback control of the throttle valve opening so that the target opening is achieved. It is being Then, by supplying fuel to the engine to achieve a preset air-fuel ratio according to the amount of intake air determined by the throttle valve opening, the air-fuel ratio of the engine is brought to the target value. .

(Problems to be Solved by the Invention) By the way, in such feedback control txt+ of the throttle valve opening, in order to improve its responsiveness, it is preferable to set a large control constant in the feedback control. However, on the other hand, if the control constant is set large in this way, for example, in the low intake air volume range of the engine, the amount of change in intake air in response to a change in the throttle valve opening is larger than in the high intake air volume range, so this sudden intake There is a problem in that torque shock occurs due to changes in the amount, impairing drivability. The same thing can be said when the engine is operating at a low rotation speed or when the gear position is a low speed gear.

The present invention has been made in view of the above points, and its object is to control the throttle valve opening by changing the control constant in the feedback control of the OJ throttle valve opening as described above in accordance with the operating state of the engine. While ensuring good responsiveness of feedback control of valve opening,
The purpose is to improve drivability by preventing the occurrence of torque shock.

(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 the target intake air ff1Ac+ is determined according to the accelerator operator α,
Engine throttle valve control 1 in which the opening degree θR of the throttle valve is feedback-controlled so as to reach the target value! At the same time, an operating state detecting means 20.27 for detecting the operating state of the engine is provided, and the control constant k in the feedback control of the throttle valve is determined according to the engine operating state by receiving the output of the operating state detecting means. This configuration includes a control constant changing means 37 for changing. Specifically, the control constant changing means 37 decreases the control constant as the engine operates in a low rotational speed range, a low intake air amount range, or a low speed gear W.

(Function) With the above configuration, the present invention provides feedback ff to set the throttle valve opening IfJ, θR to the target opening θ1 or target intake ff1Ac1 according to the accelerator operation amount α.
In the case of 1L control, the control constant k in the feedback control of the throttle valve is changed according to the operating state of the engine. From this, it is possible to ensure good responsiveness of feedback control by setting the control constant k to a large value during normal operation of the engine, while controlling the By making the constant small, the amount of change in intake air relative to the change in valve spacing can be made as small as possible, and torque shock can be prevented.

(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, 2 has one end open to the atmosphere via an air cleaner 3, and the other end opened to the atmosphere. An intake passage 4 opens to the engine 1 and supplies 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 denotes an accelerator pedal that is depressed in response to engine output requirements; 6 a throttle valve that is disposed in the intake passage 2 and controls the intake air; the throttle valve 6 is different from the accelerator pedal 5; There is no linkage relationship between the two, and it is electrically controlled by the amount of depression of the accelerator pedal 5, that is, by the accelerator operator. Reference numeral 7 denotes a throttle actuator comprising a step motor or the like that closes the throttle valve 6 17i1. 8 is a catalyst device which is mediated by the exhaust passage 4 and is used to purify exhaust gas.

Further, 9 has one end opening upstream of the catalyst device 8 of the exhaust passage 4 and the other end opening downstream of the throttle valve 6 of the intake passage 2.
An exhaust gas recirculation passage 1o that recirculates part of the exhaust gas from the exhaust passage 4 to the intake passage 2 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 10, which is made of a diaphragm device whose operation 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 to 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 that detects the depression 4 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; 2
Reference numeral 1 denotes an intake air temperature sensor which is also arranged upstream of the throttle valve 6 in the intake passage 2 and detects the intake air temperature, 22 a throttle position sensor which detects the opening degree θR of the throttle valve 6, and 23 a 1 degree TW of engine cooling water. A water temperature sensor 24 is arranged upstream of the catalyst device 8 in the exhaust passage 4 and detects the air-fuel ratio λ of the engine 1 from the oxygen concentration component in the exhaust gas. A sensor 25 is attached to the recirculation control valve 10. Exhaust 3! ! This is a reflux sensor that detects the flow time, and 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 throttle actuator 7, solenoid valve 11, and Fuel injection valve '12
is controlled. Furthermore, the control unit 26
An igniter 27 is connected as an input, and a signal indicating the number of ignitions, that is, the engine rotational speed Ne is input. Also,
A dust distributor 28 and two batteries are connected as inputs to the control unit 26, and receive signals of ignition time III], J5, and battery voltage Vs, respectively. The air flow meter 20 and the igniter 27 determine the operating state of the engine (intake air mQa R
and the engine rotational speed Ne).

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 In ili control system will be described. MAI is a target value Qa+ of air to be supplied to the engine 1, which is set so that the air-fuel ratio is set in advance for the accelerator operation amount α. The first map 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 operation amount α. M
Az is the minimum air fi Q am to achieve the air-fuel ratio necessary for idle up with respect to the engine coolant temperature Tw.
is set, and receives the output from the water temperature sensor 23 and sets the minimum air amount Qam for water temperature correction according to the engine cooling water record W.

31 is the first map MAIJ5 and the second map MAIJ5.
2, and selects the maximum value Qa2 of the target air ff1Qa+ obtained from the first map MAI and the minimum air flIQam for water temperature correction obtained from the second map MA2. Yes, when the above target air amount Qa+ is lower than the minimum air amount for water temperature correction 1flQam, the minimum air amount for water temperature correction Qa is set to increase the idle.
m is selected to ensure good engine drivability. Moreover, MA3 is the maximum air ff1Q determined by the engine rotation tk Ne with respect to the engine rotation speed Ne.
a The third map where M is set, and the igniter 2
7 bs r, etc., and the maximum air amount QaM is set according to the engine rotation vlNe. 3
2 is the maximum value selection circuit 31 and the third map MA3.
This is a minimum value selection circuit that receives each output of When Qa1 exceeds the maximum air amount QaM determined by the engine speed Ne, it is meaningless to set the target value to be more than the amount of air that can be taken in when the throttle valve 6 is fully open, so the maximum air amount mQa M is selected. By limiting the maximum value, a full open signal corresponding to all six throttle valves is output. As described above, the target air amount Qa3 is calculated for the accelerator operation amount α, taking into account the correction for the engine cooling water m U T w and the correction for the maximum air amount for all the throttle valves 6 determined by the engine rotation speed Ne.
is found.

Furthermore, 33 receives the output from the minimum 1tlt selection circuit 32, and converts the target air amount Qaa to the engine rotational speed Ne.
The intake air m A c 1 per cylinder in a 4-cylinder engine is calculated using a divider that divides by the value doubled (NeX2). HA4 and HA5 are fourth and fifth maps in which the throttle valve opening θ1 or θIE that should be the target intake ff1Ac+ with respect to the engine rotational speed Ne at the time of stopping exhaust gas recirculation and at the time of exhaust gas recirculation are set, respectively;
Both maps MA4+ MA5 are selected by the recirculation switch 34 which switches between exhaust recirculation stop and exhaust recirculation in response to the fH signal from the recirculation sensor 25, and receive the output from the divider 33 to determine the target intake air ff1Ac+. The throttle valve opening degree θ1 or θ1ε is set. Further, 35 is an intake air amount feedback correction module, which receives the target intake air amount A from the cylinder remover 33 as will be described in detail in the section.
In addition to receiving the ct signal, the air flow meter 2
The actual intake air ff1Ac per cylinder is calculated using the actual air ff1QaR and the engine rotational speed Ne based on the signals of the actual air mQap and the engine rotational speed Ne actually measured by 0.
p and the target intake air fftAC+ are compared, and a feedback correction coefficient CaFs for feedback correction of the throttle valve opening is calculated according to the width difference. Further, 36 is the fourth or fifth map MA4.
．． MA5 and intake air amount feedback correction module 3
5, the map MA4.5 receives each output from the map MA4. A multiplier that corrects the target throttle valve opening θ1 or θIE obtained by MA5 by the feedback correction coefficient CaFB obtained by the intake air amount feedback correction module 35, the target throttle valve opening corrected by the multiplier 36. degree θ2
The signal is output 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.

As a main component of the present invention, the intake air amount feedback correction module 35 operates according to the flowchart shown in FIG. That is, in FIG. 4, first, in step S1, signals of actual air mQa R from the air flow meter 20, engine speed N8 from the igniter 27, and throttle valve opening θR from the throttle position sensor 22 are read. Later, step $
2, engine speed Ne and actual air ff1Qa
Based on a control constant map set such that the smaller R becomes, the smaller the control constant k in feedback control of the throttle valve 6 becomes. In other words, this control constant is set too high in the engine's high-speed operating range and high intake ffi range, and
It is set smaller as the II/i decreases and the intake air amount becomes lower. Next, in step S3, the actual air intake amount ff1QaR is divided by the value obtained by doubling the engine speed Ne to determine the actual intake air flow rate per cylinder, and then in step S4, the target intake air amount △C1 and the actual intake air amount are calculated. The intake air ff1Ac R is compared in size, and when AC,>ACR is YES, the feedback correction coefficient QaFa is updated at step $5 to the value obtained by adding the above control constant k to it (=Ca F s +k), and Act≦ACR. When the answer is No, the feedback correction coefficient CapB is updated in step 8.5 to a value obtained by subtracting the control constant k from it (=ca F s −k), and after each iQms is served in step S7, the process returns to step S1. I'll answer that to you. Here, in step $2 above, the engine is operated so that the control constant k in the filled pack control of the throttle valve 6 is large in the high rotation range and high intake air amount area, and becomes smaller as the rotation speed and low intake air amount area becomes lower. It constitutes a control constant changing means 37 that changes C depending on the state (engine speed and intake air).

Next, referring to the fuel supply amount control system shown 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 mα.
I am trying to set it. May is the second map M above.
This is the seventh map in which the minimum fuel fiQfm is set for the engine cooling water temperature Tw so that the air-fuel ratio necessary for idle up is obtained for the air amount Qam set in A2, and the map is based on the output of the water temperature sensor 23. The minimum fuel amount for water temperature correction Qfm is determined according to the engine cooling water temperature Tw.
Set. 39 is the sixth map Ms6 and the seventh map.
After receiving each output of map MB7, the target fuel rl'rQf + determined by the sixth map Mes and the seventh map MB7
The maximum value (direct selection circuit) that selects the maximum value Qf2 from the minimum fuel fjlQfm for water temperature correction found in
When the target fuel amount Qf+ is lower than the minimum fuel amount Qrm for water temperature correction, the minimum fuel amount Qfm for water temperature correction is selected to increase the idle, thereby ensuring good engine operability. Also, M day s is the third map M83 above.
An eighth map in which the maximum fuel amount QfM is set for the engine speed NC so that the maximum air fuel amount QfM becomes a preset target air-fuel ratio for the maximum air FJQaM set at Set a Q f M. 40 is the maximum value selection circuit 39 and the eighth
A minimum value selection circuit that receives each output of the map Mag and selects the minimum value Qf3 of the maximum fuel amount Qfz determined by the maximum value selection circuit 39 and the maximum fuel ffiQfM determined by the eighth map Mea, The above target fuel amount Qf1
exceeds the maximum fuel amount QfM determined by the engine speed Ne, that is, as described above, the target air amount Qa+
exceeds the maximum air IQaM determined by the engine speed Ne, and when the target is more than the amount of air that can be taken in with the throttle valve 6 fully open, the maximum air ffl Q
aM is selected, and the maximum fuel mQfM is selected to correct the target value QI'+ 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 accelerator operation amount α is considered to be corrected for the engine coolant temperature Tw and the maximum fuel amount for all throttle valves 6 determined by the engine speed No. 1. The target fuel ff1Qfz is determined.

Then, the target fuel ff1 from the maximum value selection circuit 40 is
The Qf 3 signal is transmitted to the remover 41, the first to third boarders 42 to
44, is output to the fuel injection valve 12 via the fuel cut switch 45 and the fuel injection valve correction circuit 46. The fault remover 41 receives the output from the minimum value selection circuit 40,
The fuel supply FIQf'+ per cylinder is calculated by dividing the target fuel ff1Qf3 by the engine rotation speed No, assuming that fuel is injected into two cylinders at the same time. Further, the first multiplier 42 calculates the target fuel supply amount Qfi calculated by the interrupter 41 using the water temperature correction coefficient CTW and the enrich correction module 47 for the engine cooling water temperature Tw calculated by the ninth map Msq. Target fuel supply ff1Q is calculated by multiplying by the enrichment correction coefficient CER.
This is to calculate fi+. This enrichment correction module 47 performs enrichment correction to increase the fuel supply amount by, for example, 8% when the intake air ff1Ac+ with respect to the engine speed Ne is in the enrichment line region based on the zone (No. 8) from the zone determination module 51 to be described later. It outputs a coefficient CER (for example, 1.08>).

Further, the second multiplier 43 converts the target fuel supply FFt Q r i + obtained by the first power II2 into the learning correction coefficient 0STO obtained by the fuel learning correction module 48.
And f! Target fuel supply fTt Q f with mourning correction! 2
Q is given. This fuel learning correction module 4
8 is based on the zone signal from the zone determination module 51 and the fuel feedback correction coefficient CrFs signal from the fuel feedback correction module 49, which will be described later.
When, for example, 2 seconds or more have elapsed after the fuel feedback correction condition was established in the fuel feedback correction module 49, if the fuel learning correction coefficient C9TD is set to its initial value -1, 0, then the following formula % formula % The peak value of CfFa + bottom hllI)/16-1.0' of the past eight CfFBs and is sequentially updated and output.

Further, the third multiplier 44 multiplies and corrects the target fuel supply ff1QfL obtained by the second multiplier 43 by the fuel feedback correction coefficient 0fFB obtained by the fuel feedback correction module 4 to correct the target fuel supply ff1Qf.
This is to calculate ia. This fuel feedback correction module 49 is based on the zone signal from the zone determination module 51 and the air-fuel ratio λ signal from the 02 sensor 24, for example, under the following conditions: ■ Engine cooling water temperature Tw>60°C ■ Intake air ff1Ac+ ≧10 of the cylinder stroke volume %■
The intake air ff1Ac+ relative to the engine rotation @Ne is outside the enrich line and the tunnel cut zone. ■ When the 02 sensor 24 is active, the fuel supply amount is feedback-controlled. ．．
8≦QfFB≦1.25, the proportional constant P=0.06, and the integral constant r−0.05/sec are output.

In general, the twin cut switch 45 is controlled to open and close by an output signal from the twin cut control module 50. Based on the zone signal and target intake air amount AC+ signal from the zone determination module 51, the twin air cut control module 50 operates under the following conditions, for example: ■ Engine cooling water temperature Tw>60°C ■ Intake air fiAc+<10% of cylinder stroke volume ■ Engine When the rotation speed Ne > 100 Orpm is satisfied,
This control opens the twin unit cut switch 45 to cut off fuel injection. Here, the zone determination module 51 determines the engine rotation speed Ne, the target intake f.
Condition determination signals (zone signals) for each of the control modules 47 to 50 are created based on the signals of itAc+, engine cold water level Tw, and air-fuel ratio 2.

Furthermore, the fuel injection valve correction circuit 46
Upon receiving the target fuel supply 1Qfi3 signal from the 3 multiplier 44 and the battery voltage Va signal from the two batteries, the pulse signal as the target fuel supply amount signal to the fuel injection valve 12 is corrected according to the battery voltage Vs, and the fuel It outputs to the injection 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 amount is controlled to the target value.

Therefore, in the above embodiment, the target air m to be supplied to the engine 1 is determined in response to the accelerator operation I phase α, and the target opening degree of the throttle valve 6 is determined based on this target air amount. throttle valve 6
The opening degree of is feedback-controlled, and the target intake air ■ is supplied to the engine 1. At this time, the control constant k in the feedback control of the throttle valve 6 is changed by the control constant changing means 37 so that it becomes larger in the high rotational operating range of the engine and in the high intake air position, and becomes larger in the low engine rotational operating range and in the low intake air intake area. Since the control constant k is set to be relatively small, feedback control of the throttle valve 6 can be performed with good responsiveness during normal operation of the engine due to the large control constant k. On the other hand, when the engine is operating at low speeds and when the intake air amount is low, the small control constant k is used to suppress the amount of change in intake air in response to changes in the opening degree of the throttle valve 6 as small as possible, thereby suppressing the occurrence of torque shock. I can do it. Therefore, the responsiveness of the feedback control of the throttle valve 6 can be ensured well, and the operability of the engine can be improved.

In addition, a target air amount and a target fuel amount are respectively determined for the accelerator operation amount α, and the intake air amount and the fuel fit (co-supply By being controlled to be the value,
Since the intake air amount and the fuel supply amount change simultaneously to the target (directly) without any time lag in response to changes in the accelerator operation Mα, there is no possibility of fuel response delays occurring even during transient engine operation. 41, the air-fuel ratio of the engine can be well controlled to the target air-fuel ratio tRe-, and therefore the acceleration performance and driving performance of the engine can be improved without causing misfires or the like that occur in the conventional engine.

Furthermore, since the intake air amount and fuel supply for the accelerator operation port α are simultaneously controlled to a preset air-fuel ratio, the target air-fuel ratio can be precisely controlled without requiring feedback control I. Therefore, control can be simplified.

In the above embodiment, the control constant changing means 37 changes the control constant k the lower the engine rotational speed range and the lower intake air amount range.
Although the gear position has been changed to be smaller, the gear position may be detected as the operating state of the engine and the low speed gear time control constant k may be reduced, and the same effect as in the above embodiment can be achieved.

Further, in the above embodiment, the target air volume (2) is first determined according to the accelerator operation amount, and then the target throttle valve opening degree is determined based on this target air amount, and the throttle valve 6 is adjusted so that the target throttle valve opening degree is reached. This method was applied to a system that performs feedback control, but it is also applicable to a system that directly obtains the target throttle valve opening or target air ω according to the accelerator operator and performs feedback control of the throttle valve so that the target (direct) is reached. The same applies to

(Effects of the Invention) As described above, according to the present invention, when the opening degree of the throttle valve is feedback-controlled to the target opening degree or the target intake air amount according to the accelerator operation amount, III in the feedback control of the throttle valve is performed. Since the lit constant is changed according to the operating condition of the engine, while ensuring good responsiveness of feedback control, it is possible to reduce torque shock when the engine is running at low rotation speeds, at low intake air volume, or when in low gear. It is possible to prevent this and improve drivability, thereby achieving both the responsiveness of throttle valve control and the drivability of the engine.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the present invention. Figures 2 to 4 show embodiments of the present invention, Figure 2C is an overall schematic configuration diagram, Figure 3 is a block diagram 0 showing the operation flow of the control unit, and Figure 4 is a block diagram showing the intake air amount feedback. FIG. 3 is a flowchart diagram showing the operation of the correction module. 1...Engine, 5...Accelerator pedal, 6...
Throttle valve, 7... Throttle actuator, 1
One...Accelerator pedal position sensor, 2o...
Air flow meter, 22... Throttle position sensor, 26... Control unit, 27... Igniter, 35... Intake air amount feedback correction module, 37... Control constant changing means.

Claims (3)

[Claims] (1) In an engine throttle valve control device that determines a target throttle valve opening or 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 present invention is characterized by comprising an operating state detection means for detecting the operating state, and a control constant changing means for receiving the output of the operating state detecting means and changing a control constant in the feedback control of the throttle valve according to the engine operating state. Throttle valve control device for engines. (2) The control constant changing means decreases the control constant as the engine runs at lower speeds.
) The throttle valve control device for the engine described in item 2. (3) The control constant changing means decreases the control constant as the intake air amount region of the engine decreases.
) Throttle valve control device for the engine described.