JPS6193237A - Throttle valve controller for engine - Google Patents

Abstract

PURPOSE:To aim at improvements in responsiveness in suction quantity control and control accuracy ever so better, by installing an exhaust reflux quantity detecting device, which detects an exhaust reflux quantity, and a control constant changing device which changes a control constant in feedback control for a throttle valve. CONSTITUTION:Desired throttle valve opening theta1 or desired suction quantity Ac1 is found according to an accelerator operated variable alpha, and opening thetaR of a throttle valve is controlled for feedback so as to become this desired value. An exhaust reflux quantity detecting device 25 detects an exhaust reflux quantity to flow back to engine. There is provided with a control constant changing device 37 which receives output R of the exhaust reflux quantity detecting device 25 and makes a control constant K in feedback control for the throttle valve larger according to an increase in the exhaust reflux quantity. Thus, irrespective of the amount of exhaust reflux quantities, improvements in responsiveness in suction quantity control as well as in control accuracy are promoted.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an engine throttle valve control device, and in particular, to feedback control of throttle valve opening in order to obtain a predetermined intake air amount with respect to an accelerator operation amount indicating a required engine output. Regarding what you choose to do.

(Prior art) Conventionally, as a technology for controlling the air-fuel ratio of the engine to a predetermined air-fuel ratio in response to the accelerator operation amount indicating the required engine output,
As shown in Japanese Unexamined Patent Publication No. 51-138235, there is an accelerator detecting means for detecting an accelerator operation opening, and an apparatus that receives the output of the accelerator detecting means and controls the air to be supplied to the engine so that a preset air-fuel ratio is achieved. comprising a target air amount setting means for setting a target value, and a throttle valve opening degree control means for receiving the output of the target air amount setting means and controlling the opening degree of the throttle valve in order to set the air amount to the target value, Target air amount (that is, target throttle valve opening) according to accelerator operation amount
It is known that the throttle valve opening degree is feedback-controlled to obtain the target air amount. Then, the air-fuel ratio of the engine is set to the target value by supplying fuel to the engine so that the air-fuel ratio is set in advance according to the amount of intake air that is dependent on the opening of the throttle valve. It is.

(Problems to be Solved by the Invention) However, when performing feedback control of the throttle valve opening as described above in an engine that performs exhaust gas recirculation,
As the exhaust recirculation increases, the amount of fresh air taken into the engine decreases accordingly, so when there is a large amount of exhaust recirculation, changes in intake air due to changes in throttle valve opening
There is a problem in that the suspension becomes smaller, and the responsiveness and control accuracy of the intake air amount by feedback control of the throttle valve opening decreases.

The present invention has been made in view of the above, and its purpose is to provide feedback control of the throttle valve in accordance with the amount of accelerator operation in an engine that performs exhaust gas recirculation as described above.
By appropriately setting the constant depending on the amount of exhaust gas recirculation, the intake m by feedback control of the throttle valve can be adjusted.
The objective is to improve responsiveness and control accuracy.

(Means for solving the problem) In order to achieve the above object, the solution means of the present invention is the first
As shown in the figure, a target throttle valve opening θ1 or a target intake AC1 is determined according to the accelerator operation amount α, and the throttle valve opening θR is feedback-controlled to reach the target value. Valve control'
In addition to this, an exhaust gas recirculation amount detection means 25 for detecting the flow of exhaust gas recirculated to the engine, and an output R of the exhaust recirculation pre-detection means 25 are received.
The control constant change means 37 increases the control constant k in the feedback control of the throttle valve in accordance with an increase in the amount of exhaust gas recirculation.

(Function) With the above configuration, in the present invention, as the exhaust gas recirculation increases, the amount of fresh air taken into the engine decreases, and the change in the intake air with respect to the change in the throttle valve σ opening becomes smaller. However, in this case, the control constant k in the feedback control of the throttle valve increases in accordance with the increase in the amount of exhaust gas recirculation.
The reduction change in the intake air amount is compensated for, and the intake air amount is controlled to the target value with good responsiveness and accuracy.

(B; 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 m+t device according to an embodiment of the present invention, where 1 is, for example, a 4-cylinder engine, 2 has one end opened to the atmosphere via an air cleaner 3, and the other end opened 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 accordance with the engine output request, and reference numeral 6 indicates a throttle valve that is disposed in the intake passage 2 and controls the amount of intake air. 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 which is interposed in the exhaust passage 4 and purifies exhaust gas.

Further, 9 has one end opening upstream of the catalyst device 8 in the exhaust passage 4 and the other end opening downstream of the throttle valve 6 in the intake passage 2.
An exhaust gas recirculation passage 10 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.
It is connected to a fuel tank 16 via a fuel supply passage 15 provided in the P, and fuel is supplied from the fuel tank 16, and the surplus fuel is passed through a return passage 18 with a fuel pressure regulator 17 interposed therebetween. The fuel is supplied to the fuel tank 16, so that fuel at a predetermined pressure is supplied to the fuel injection valve 12.

In addition, 19 is an accelerator pedal position sensor as an accelerator detection means for detecting accelerator operation ■α from a single depression of the accelerator pedal 5, and 20 is arranged upstream of the throttle valve 6 in the intake passage 2 to detect intake air mQaR. Reference numeral 21 is an intake temperature sensor which 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 which detects the opening degree of the throttle valve 6, and 23 is an engine cooling water sensor. A water temperature sensor 424 that detects the temperature TW is disposed upstream of the catalyst device 8 in the exhaust passage 4, and a 02 sensor that detects the air-fuel ratio λ of the engine 1 from the oxygen concentration component in the exhaust gas, and a water temperature sensor 25 is attached to the recirculation control valve 10. Exhaust)! The reflux sensor serves as a flow detection means for detecting flow flfiR, and these detection signals 19 to 25 are input 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 11J3 and fuel injection valve 12 are controlled. Furthermore, an igniter 27 is connected as an input to the control unit 26, and the number of ignitions, that is, the engine rotational speed NO. The input terminals are connected to input signals of ignition timing J5 and battery voltage VB, respectively.

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, to describe the throttle valve opening control system, MAI sets the target tll'IQa+ of the air supplied to the engine 1 so that the air-fuel ratio is set in advance in response to the accelerator operation ■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 in response to the accelerator operation ■α. M
A2 is the minimum air @ Q am to achieve the air-fuel ratio necessary for C idle up with respect to engine cooling water) temperature Tw
is set, and receives the output from the water channel sensor 23 to set the minimum water temperature correction air mQam according to the engine cooling water temperature mTw.

31 is the first map Mzi+ and the second map MA.
This is a maximum value selection circuit which receives each output of 2 and selects the maximum value Qa2 of the target air 11Qa+ determined by the first map MAI and the minimum air for water temperature correction, 10am determined by the second map MA2. , the target air ff1Qa
When + is lower than the minimum air for water temperature correction mQam, the minimum air for water temperature correction mQ am@
This selection is made to ensure good engine drivability. Moreover, MA3 is the maximum air 111Q determined by the engine speed NO with respect to the engine speed FIL NO.
A third map in which aM is set, and the igniter 27
The maximum air ffiQaM is set according to the engine rotation speed Ne. 32 is
The maximum air f calculated by the maximum value selection circuit 31 upon receiving each output of the maximum value selection circuit 31 and the third map MA3
Maximum air f obtained from f1Qaz and third map MA3
This is a minimum value selection circuit that selects the minimum value Qa3 of fiQaM. Therefore, when the target air ff1Qa+ exceeds the maximum air ffiQaM determined by the engine rotation speed Ne, the throttle valve 6 is fully opened to select the amount of air that can be taken in. Since it is meaningless to set the above-mentioned suspension as a target value,
By selecting the maximum air ii Q aN and limiting the maximum value, a full open signal corresponding to the full opening of the throttle valve 6 is output. As described above, the target air class Qa3 is determined for the accelerator operating device α, taking into account the correction for the engine coolant temperature Tw and the correction for the maximum air amount when the throttle valve 6 is fully open, which is determined by the engine speed Ne.

Furthermore, 33 receives the output from the minimum value selection circuit 32, and sets the target air amount Qa3 and the engine speed Ne to 2.
A divider that divides by the value (NeX2) is used to find the intake interval Ac+ per cylinder in a 4-cylinder engine. M
A4 and MA5 are the throttle valve opening θ1 or θI E h that should be the target intake engine Δc1 for the engine rotation speed Ne when exhaust gas recirculation is stopped and when exhaust gas flow is continuous, respectively.
<The set fourth and fifth maps, both maps MA4. MA5 is switched depending on the signal from the recirculation sensor 25 when exhaust recirculation is stopped and when the exhaust flow is 32)! selected by the flow switch 34, receives the output from the divider 33, and selects the target intake mAc+ and the smooth throttle valve opening θ.
j or θ+E@82. Also, 35
is an intake air amount feedback correction module which receives the signal of the target intake △C1 from the divider 33, and
Actual air ff actually measured by the air flow meter 20
1QaR.

Actual intake air per cylinder ff1AcR calculated from actual air amount QaR and engine rotation speed Ne after receiving signals of engine rotation speed Ne and exhaust gas recirculation interval R from the recirculation sensor 25
and target intake ff1Ac+, and feedback correction coefficient Ca is used to feedback-correct the throttle valve opening according to the deviation and exhaust gas recirculation ff1R.
This is to calculate Fe.

Further, 36 is the fourth or fifth map M A a
*MA5 and intake air amount feedback correction module 3
5, the map MA4.5 receives each output from the map MA4. This multiplier corrects the target throttle valve opening θ1 or θIE obtained by MA5 with the feedback correction coefficient Car:B obtained by the intake air amount feedback correction module 35, and the correction is performed by the multiplier 36. Target throttle valve opening θ
The signal No. 2 is output to the throttle actuator 7, and the opening degree of the throttle valve 6 is adjusted (7).
It is configured to perform feedback control in accordance with 2.

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, the actual intake mAcR per cylinder is calculated from the actual air intake θaR in step Str and the engine speed Ne, and then the actual intake mAcR per cylinder is calculated based on the control constant map in which the control constant k is set for the exhaust gas recirculation fiR in step $2. The control constant k is read by the exhaust gas recirculation IR from the recirculation sensor 25. In this control constant map, the control constant k is set to 1 when the exhaust gas recirculation amount R is O, and is gradually increased as the exhaust gas recirculation amount R increases until the exhaust gas recirculation amount reaches the maximum amount. It is sometimes set to 0.5.

Next, in step S3, the target air amount Δc1 becomes the actual air mA.
c Determine whether it is larger than R, and set Y of Act>ACR
In the case of ES, it is determined that the opening degree of the throttle valve 6 is insufficient, and the feedback coefficient CaFe is changed to ca in step s4.
On the other hand, if Act<ACR is NO, it is determined that the throttle valve 6 is too close, and the feedback coefficient CaFe is set to Cat=Cat in step s5.
e-, and after waiting for 1 Qmsec in step S6, the process returns to step SI. Here, the above step S
2 constitutes a control constant changing means 37 that receives the output of the recirculation sensor 25 (exhaust gas recirculation amount detection means) and increases the control constant k in the feedback control of the throttle valve 6 in accordance with the increase in the exhaust gas recirculation ff1R.

Next, to describe the fuel supply m control system in FIG.
A sixth map in which direct Qf+ is set, which receives the output from the accelerator pedal position sensor 19 and outputs a target fuel ff to be supplied to the engine 1 according to the accelerator operation amount α.
1Qf+ is set. MB7 is the second above
This is the seventh map in which the minimum fuel ffiQfm for the engine cooling water temperature aTw is set so that the air-fuel ratio necessary for idle up is obtained for the air amount Qam set in map MA2, and the lowest fuel ffiQfm is set for the engine cooling water temperature aTw. Upon receiving the output, the minimum fuel for water temperature correction ff1Qftn is set according to the engine coolant temperature Tw. 39 receives each output of the sixth map Ms6 and the seventh map May, and calculates the value obtained from the sixth map Mss (=fuel IQr+ and the minimum fuel ffiQfm for water temperature correction obtained from the seventh map May).
This is a maximum value selection circuit that selects the maximum value Qf2 among these, and the target fuel amount Of+ is the minimum twist for water temperature correction of 11m.
When the engine temperature drops below Qfm, the minimum fuel amount Qfm for water temperature correction is selected to increase the idle, thereby ensuring good engine operability. In addition, Maa is the engine rotation speed N so that the preset target air-fuel ratio is achieved with respect to the maximum air fitQaM set in the third map MA3.
This is the eighth map in which the maximum fuel quantity Qr diagram for +3 is set, and the maximum fuel quantity Qr is
Set fM. 40 receives each output of the maximum value selection circuit 39 and the eighth map Msa, and outputs the maximum value selection circuit 3.
The minimum value QI' of the maximum fuel mQf2 obtained in 9 and the maximum fuel characteristic QfM obtained in the 8th map Maa.
This is a minimum value selection circuit that selects the above target fuel amount Q.
Maximum fuel amount Qf where f1 is determined by engine speed NO
When it exceeds M, that is, as mentioned above, the target air @Q
a+ is the maximum air ffi determined by the engine speed NO.
When the target value is to exceed QaM and exceed the amount of air that can be taken in with the throttle valve 6 fully open, the maximum air m
By selecting Qa M and selecting the maximum fuel 1nQfM, the target value Of+ is corrected so that it becomes a preset target air-fuel ratio for the intake air amount supplied to the engine 1. As described above, as in the case of the air amount, the accelerator operating word α is corrected based on the correction J3 for the engine cooling water temperature Tw and the maximum fuel amount for all the throttle valves 6 determined by the engine rotation speed NB. The target fuel ff1Qf3 is determined in consideration of the following. The target fuel ff1Qf3 signal from the maximum value selection circuit 40 is transmitted through the cotton remover 41, the first to third multipliers 42 to 44, the fuel cut switch 45, and the fuel injector correction circuit 46. :
It is output to the fuel injection valve 12. The anti-fraud device 41 has a minimum ti11! Upon receiving the output from the selection circuit 40, the target fuel m
The fuel supply amount Qfi per cylinder is calculated by dividing Qf 3 by the engine rotation speed N'e assuming that fuel is injected into two cylinders at the same time. The first multiplier 42 also calculates the target fuel supply amount Q obtained by the divider 41.
fi is the engine cold I determined by the ninth map M139.
The water temperature correction coefficient 0 cv for I water wetness a T v and the enrichment correction coefficient CER″cf obtained by the enrichment correction module 47!Target fuel supply mQfi after correction
+ is calculated. This enrichment correction module 47 calculates the intake air ff with respect to the engine rotation speed Ne based on a zone signal from a zone determination module 51, which will be described later.
When 1Ac+ is in the enriched line region, the enrichment correction coefficient C is set to increase the number of fuel supply machines by, for example, 8%.
It outputs εR (for example, 1.08).

Further, the second multiplier 43 multiplies and corrects the target fuel supply 1Qfil obtained by the first multiplier 42 by the learning correction coefficient C5TD obtained by the fuel learning correction module 48 to obtain the target fuel supply m Q f i 2 is calculated. This fuel learning correction module 48 performs the calculation in the fuel feedback correction module 49 based on the zone activation number from the zone determination module 51 and the fuel f and C-dpock correction coefficients 0fFB Shintan from the four fuel feedback correction modules described below. For example, when 2 seconds or more have elapsed after the fuel feedback correction condition was established, the fuel learning correction coefficient C5TD is set to its initial value = 1.0, and then the following formula % formula % Peak value of Cfpa + Bottom of CfFe of the past 8 times value)/16. -1.0) and output the updated data sequentially.

In addition, the third @ great device 44 multiplies and corrects the target fuel supply ff1a ti2 obtained by the second @ calculator 43 by the fuel feedback correction coefficient Cfps obtained by the feedback correction module 49 to achieve the target fuel supply. fuel supply f
fi Q f i a is calculated. Based on the zone signal from the zone determination module 51 and the air-fuel ratio λ signal from the 02 sensor 24, the fuel feedback correction module 49 calculates, for example, the following conditions: Engine coolant temperature Tw>60'C Intake aAc
+≧10% of cylinder stroke volume ■ Engine speed Ne
02 sensor 24 is active, the fuel feedback correction coefficient CfpeC, for example, 0.
8≦C [“8≦1.25, proportional constant P = 0.06, integral constant I = 0.05/sec)” This is the case where full output is achieved.

Further, the twin cut switch 45 is controlled to open by an output signal from the twin cut control module 50. Based on the zone signal and target intake air amount Act signal from the zone determination module 51, the twin air cut control module 50 operates under the following conditions, for example: ■ Engine coolant temperature Tw>60°C ■ Intake IAc+<10% of cylinder row fl volume■ When the engine rotational speed Ne>11000 rp is satisfied, control is performed to listen to the twin cut switch 45 to cut fuel injection. Here, the zone determination module 51 determines the engine rotation speed Ne, the target intake air amount Ac
Condition determination signals (zone signals) for each of the control modules 47 to 50 are created based on the signals of +, engine coolant temperature Tw, and air-fuel ratio λ.

Furthermore, the fuel injection valve correction circuit 46 includes the third fuel injection valve correction circuit 46.
Receives the target fuel supply in Q f '3 signal from the multiplier 44 and the battery voltage Va signal from the battery 29, and generates a pulse signal as the target fuel supply hot water No. 1g to the fuel injection valve 12 in accordance with the battery voltage VB. There is something that is corrected and output to the fuel 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 injection valve 12 is configured to control the supply of fuel 1°31 times directly to the target.

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 by closing this target air amount, and the throttle valve 6 is adjusted so that this target interval If is reached.
The opening degree is feedback-controlled, and the target intake air amount is supplied to the engine 1. At that time, during exhaust gas recirculation, the intake air amount feedback correction module 35
By setting the control constant k in the feedback control of the throttle valve 6 to a large value in accordance with the increase in f1R, the control gain in J5 is increased in the feedback control of the throttle valve 6, and the change in intake air amount due to the feedback control is increased. Therefore, it is possible to compensate for the decrease in the amount of fresh air taken in due to the increase in the amount of exhaust recirculation, which reduces the change in the amount of intake air in response to changes in the throttle valve opening. can be controlled.

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 values, the intake air amount and the fuel supply amount are simultaneously set to the target values in parallel. By being controlled so that the intake air amount and the fuel supply opening change simultaneously to the target 1 shift without any time lag in response to changes in the accelerator operation amount α, the The engine's air-fuel ratio can be precisely controlled to the target air-fuel ratio without causing fuel response nearness, thereby improving the engine's acceleration performance and driving performance without engine breathing or misfire. be able to. Moreover, the accelerator operation mα
Since the intake air (5) and the fuel 1'31 supply are simultaneously controlled to a preset air-fuel ratio, the target air-fuel ratio can be accurately controlled without requiring feedback control. Therefore, control can be simplified.

In the above embodiment, the control constant changing means 37 was closed so as to linearly increase the control constant k in accordance with the increase in exhaust gas recirculation, but the control constant changing means 37 was closed so as to increase the control constant k stepwise. It's okay.

Further, in the above embodiment, the target air opening is first determined according to the accelerator operation amount, and then the target throttle valve opening is determined based on this target air opening, and the throttle valve is adjusted so that the target throttle valve opening is achieved. 6 has been applied to a device that performs feedback control, but it can also be applied to a device that directly determines the target throttle valve opening or target air amount according to the accelerator operation amount, and performs feedback control of the throttle valve so that the target 1 shift is achieved. The same applies to 0! :, is.

(Effect of the invention) As explained above, according to the present invention, the exhaust j! The control constant in the throttle valve feedback control is increased in accordance with the increase in the flow m, and the control gain 1'J is increased, so that the intake air amount by feedback control of the throttle valve distance can be controlled with good responsiveness. Accurately eye a Iil! It is possible to improve the responsiveness d'3 and control accuracy of the intake level ffl+ control regardless of the magnitude of the exhaust velocity flow frl.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the j4 configuration of the present invention. Figures 2 to 4 show embodiments of the present invention, with Figure 2 being an overall schematic diagram, Figure 3 being a block diagram showing the operation flow of the control unit, and Figure 4 being the flowchart of the intake air amount feedback correction module. It is a flowchart figure which shows an operation|movement flow. 1...Engine, 5...Axle pedal, 6...
Throttle valve, 7... Throttle actuator, 1
1...Acrylic pedal position sensor, 25...
Reflux sensor, 26... control unit, 37...
...Control constant changing 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 the accelerator operation amount and performs feedback control of the throttle valve opening so that the target value is achieved, the engine Exhaust gas recirculation amount detection means for detecting the amount of recirculated exhaust gas; and control constant changing means for receiving the output of the exhaust gas recirculation amount detection means and increasing a control constant in the feedback control of the throttle valve in accordance with an increase in the amount of exhaust gas recirculation. An engine throttle valve control device comprising: