JPS59122761A - Suction air flow controller for internal-combustion engine - Google Patents

Abstract

PURPOSE:To prevent engine stall by providing means for storing learning level of duty ratio upon stoppage of car into a memory as the referential level and means for limiting the learning level within predetermined range as far as the car is stopped. CONSTITUTION:Stoppage of car is decided at the step 204 while the learning level of duty ratio is stored as the referential learning level DGS into a memory at the step 206. At the step 216, the learning level DG is attached with a guard within predetermined range from the referential learning level DGS. Consequently even when the throttle valve has fully closed after idle warming of engine, it will never cause engine stall. Furthermore engine can be restarted when the wiring of car speed sensor has broken.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the side slope of the intake air amount of an automobile engine, particularly to the control of the intake air amount during idling operation, and more specifically to the control of the intake air amount by-passing the throttle valve of the engine. This invention relates to an electronic control device for the amount of intake air installed in a passage or near solenoid type on-off actuated air control valve (idle speed control pulp).

Electronically controlled fuel injection systems (EFIs) can control the air-fuel ratio of the combustion mixture according to various requirements, so today they are used as fuel supply systems for automobile engines from the standpoint of purifying exhaust gas and improving fuel economy. It is often used in place of a vaporizer. In the EFI system called the L-Jetronic system, the fuel injection amount is calculated by the device's microcombination system according to the intake air amount measured by an air flow meter installed in the intake/air system. Then, a predetermined amount of fuel is injected into the intake air by an injector to form a combustion mixture.The intake air amount (ζ) is controlled by a throttle valve that is applied to the vehicle's accelerator pedal. The idle speed of the engine is determined by the amount of intake air that flows through the gap between the throttle valve and the throttle body when the throttle valve is fully open.Dust accumulates in this gap as the engine operates for a long period of time. As a result, the amount of intake air at idle decreases over time, which causes the engine's idle speed to decrease.Additionally, after the break-in of a new engine, the idle speed decreases over time as the engine's internal resistance decreases. In addition, in vehicles with expensive components such as near conditioners, torque converters, and power steering, it is necessary to increase the amount of air at idle when these XR devices are activated. In a conventional engine equipped with an EFI device, an idle air bypass passage is provided that completely bypasses the throttle valve, and an air control valve is provided in this bypass passage, and by controlling the operating amount of this air control valve, the idle air is controlled. In this specification, such an idle air bypass passage is referred to as an "idle speed control passage", and its air control valve is It shall be referred to as the "idle speed control valve" or single Krl5CVJ.The l5CVs that have been used so far include a single negative king operated type, a stem motor type, and an on/off operated type with a linear solenoid. There are three types: /Off operation.The flow rate of idle nitrogen through the CV' is determined by the "duty ratio" which is the percentage of the NFC time during which pulsed current is actually supplied within a unit time.Therefore, the electronic control This duty ratio
If the value Vc is calculated, the intake air at idle -? The target value vc can be decorated.

15CV opening degree? Feedback 1 and 7'C+i open loop system depending on engine operating conditions
The starter's operating condition, engine, cooling water temperature, throttle opening, vehicle speed, etc. are all judged, and when the starter is OFF, the cooling water temperature is set (for example: 70'C or higher). When there is no single speed and the throttle is fully closed, l5
CV is feedback controlled, so if any of these conditions are light, it is an open-loop cloth:
be controlled.

During feedback control, the target idle speed is generally calculated according to the presence or absence of a load on the air conditioner, and alternatively, the difference between the current speed and the target idle speed is calculated, and this difference is calculated. The duty ratio is fully calculated by integral proportional operation according to the following.

That is, the integral term and the proportional term of the duty ratio are determined according to the rotational speed difference, and the estimated term is added to these as necessary to obtain the total final duty ratio, and this final duty ratio t is By outputting a pulse signal to the ISCV, it is possible to feedback control the amount of intake air during idling and thus the idling rotation speed. Then, the sum of the integral term and the proportional term is recorded in a non-volatile memory as a learned value.

When controlling the open loop 1b1, the learning 11iffi'f! recorded during feedback control is performed. 1" reading from the memory - This learned value is corrected as necessary by 29 days to obtain the final duty ratio. In this way, when the open loop is controlled, learning control is performed and the idle speed can be brought closer to the target value. As mentioned above, one of the elements for determining the success or failure of the feedback condition is the throttle opening. This throttle opening is
It is detected from the throttle valve body, which is connected to the shaft of the slot J-reno-rube, like a circumference. The throttle position sensor consists of a switch having a plurality of contacts, and the contact corresponding to zero throttle opening is called an idle contact. However, due to the structure of the throttle position sensor, the idle contact actually turns ON within a certain range of throttle opening, and generally when the throttle opening is between 0 and 3 degrees. The idle contact is turned ON. For this reason, as will be described in more detail later with reference to all drawings, in conventional intake air amount control devices, the idle contact is turned ON even when the throttle valve is actually slightly open. Feedback control of l5CV is started as soon as possible. This situation often occurs, for example, when the engine is running. When feedback control of the intake air amount starts with the throttle valve slightly open, the intake air amount increases due to the air flowing through the throttle valve itself and the engine idle speed increases, so the engine idle speed increases. The duty ratio of 15CV is controlled to the closing side in order to decrease it toward , and along with A, the learning 1st shift is also updated to the closing side. When fully closed, feedback control starts from the learned value that has been updated to a smaller value, so the amount of intake air is temporarily too small, the idle speed undershoots, and in the worst case, an engine storm may occur. cause.

The present invention has been devised in view of several points that occurred during the steaming of the prior art, and the throttle valve is fully closed after the engine has been revved up, so that the intake air can be used without causing the engine to stall at FC. The object is to provide a quantity control device.

For this reason, the invention is based on an on-off operating two-tun magnetic air control valve that is provided in a bypass that bypasses the throttle valve of the engine and controls the amount of intake air that flows through the bypass according to the duty ratio of the pulse No. 1g. , means for setting an integral term and a proportional term of a duty ratio of a pulse signal according to the difference between the startling idle rotation speed and the current idle rotation speed of the engine, and calculating the interest of the integral term and the proportional term. means for setting a learned value of the duty ratio; means for recording the learned value in a memory; and means for calculating a final duty ratio during feedback control by adding the integral term, the proportional term, and an expected term if necessary. means for reading out the learned value from the memory and correcting it as necessary to fully set the final decouty ratio during open loop control; In the intake air amount control device for an internal combustion engine, the intake air amount control device for an internal combustion engine comprises: a means for recording the learned value when the vehicle is stopped in another memory as a reference learned value when the vehicle is stopped; As long as the learned value is within a predetermined range from the learned value t - the reference learned value.

Preferably, the other memory in which the reference learning value is recorded is a non-volatile memory.

Hereinafter, a conventional intake air amount control device and embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of an electronically controlled fuel injection engine equipped with a conventional intake air amount control device and the present invention. The intake system of the engine consists of an air flow meter housing 10 connected to an air cleaner (not shown), an intake pipe 12, a surge tank 14, an intake manifold 16, and an intake port 18. The intake manifold 16 is provided with an injector 20 for each cylinder. The injector 20 is connected to a pressurized fuel supply system (not shown), and opens in response to a pulse signal output from an electronic control unit (ECU) 30 to inject a predetermined amount of fuel into the intake air to create a combustion mixture. It is possible to form.

A throttle valve 32 that moves on the accelerator pedal of an intake pipe 121CH vehicle is provided, and the shaft of this throttle valve 32 has a plurality of contact points. O air flow meter housing 1 (HCId) A measuring plate 36 for measuring the intake air flow rate is connected to the throttle position sensor 34 that has the air flow meter housing 1 (HCId) so that a signal corresponding to the throttle opening can be output to the electronic control unit (ECU) 30. The latter is connected to a potentiometer-type intake air amount sensor 38 so that it can output a signal tEcU30 corresponding to the intake air flow 'It.

An idle speed control passage 48 is provided between the intake pipe 12 and the surge tank 14, and even when the throttle valve 32 is fully closed, the air necessary for idling the engine bypasses the throttle valve 32 and is supplied to the engine. It has become so. The idle speed control passage 48 is provided with a horizontal solenoid type on/off air control valve, i.e., idle speed control pulp (ISCV) 5075E.1. :(1'
) The ISCV 50 is opened and opened by a pulsed drive current output from the ECU 3o, as is well known.

The distributor 52 is provided with a known rotation angle sensor 54, which can output a signal 'kEcU30 according to the angular position and rotational speed of the engine crankshaft. 56 is a cylinder block, 58 is a piston, 60 is an exhaust manifold, and 62 is a vehicle speed sensor.0 FIG. 2 is a block diagram of the electronic control unit (ECU) 30 shown in FIG. It is a combination coater. electronic control unit) (E
CU) 30 is a microprocessor (M
PU) 70, a read-only memory (ROM) 72 in which arithmetic processing programs and arithmetic constants are stored,
It is comprised of a random access memory (RAM) 74 consisting of a nonvolatile storage section and a continuous storage section, and a clock 76 that generates all of the various clock signals.

MPU70, ROM72 and RAM74 are common bus 78
are connected to each other by the clock 76UMPIJ
70 and sends a clock signal directly to the MPU 70.

The analog signal from the air flow meter 38 is sent to the buffer 8.
0 and an A/D converter 84 via 82 multiplexers.
is input to the input/output port 86 and converted to a digital signal.
and is read into the MPU 70 via the common bus 78.

A signal from the throttle position sensor 34 is read into the MPU 70 via an input port 88, and is input to the vehicle speed sensor 62.
The signals from rotation angle sensor 54 and rotation angle sensor 54 are read into MPU 70 via shaping circuit 90 and input port 88, respectively.

Based on the data read from each sensor and stored in the RAM 74, the MPU 70 performs all the arithmetic processing described below in accordance with the program stored in the ROM 72VC.
The duty ratio of is fully calculated. The obtained duty ratio is transferred to a register in the MPU 3O in the same way as in the conventional method, and by counting down with the clock signal from the clock 76, it is output as a pulse signal with the desired duty ratio via the output port 90'i. The signal is sent to the drive circuit 92, where it is amplified and supplied to the l5CV50 in the form of a drive current.

FIG. 3 is a flowchart of a conventional program for calculating the duty ratio of the l5CV. This duty ratio calculation routine is an interrupt routine started by a signal from the rotation angle sensor 54, and is executed every revolution of the crankshaft. It is something that will be done. At step 101 t/'i
In the previous routine, the non-volatile RAM of RAM74
The learned value DG' of the duty ratio recorded in is read and transferred to the volatile RAM. Step 102 (d engine is l5
This is a step to determine whether the conditions are such that CV50 full feedback control is possible.For example, the starter switch, engine coolant temperature, vehicle speed, and throttle opening are determined, and if the starter switch is OFF and the coolant temperature When the set value is exceeded, the vehicle speed is zero, and the throttle valve is fully closed, the process proceeds to step 103 and subsequent steps, and complete feedback control of the I5CV50 is performed. When the starter is operating, when the cooling water temperature is below the set value, when the vehicle speed is high, when the throttle valve is open (in step 113 and below, the l5CV50 is under open loop control. .

If the feedback condition is satisfied 1c, in step 103, the target idle speed NF of the engine is selected in accordance with the operating state of accessory devices such as the near conditioner and torque converter. That is, when the compressor of the near conditioner is driven or when the torque converter is in the drive range [U] Since the engine load at idle changes, a different ring idle speed NF is selected.

In step 104, the difference INE-NFl between the current engine speed NE and the target engine speed NF is calculated. In order to feedback-control l5CV50 by proportional-integral operation based on INE-NFIvc obtained in this way,
In steps 105 to 111, a procedure for fully calculating the following equation is performed.

D=D engineering+Dp+])r ・・・・・・・・・
・・・・・・・・・(1) Here, the final duty ratio of the pulse current applied to D=5CV50, JUde=-
These are an integral term for the T ratio, a ratio sequence term for DP, and a probability term for Dtld.

What I used to calculate the integral term was to take the duty ratio of the previous routine (which is executed every revolution of the crankshaft as described above in the routine shown in Figure 3) and use it as a starting point to calculate the duty ratio. This is to correct the proportional term DP? The purpose of this control is to quickly recover when the target rotation speed overshoots or undershoots significantly, and even if JJjDy' is used, the target rotation speed is immediately restored when a load such as a near conditioner or torque converter is applied. This is to bring it closer to the value.

That is, in step 105, I obtained in step 104 is
Based on NF-NFI, the correction amount ΔD of the integral term is RO
Read from M72. For this reason, a map as shown in A4 diagram (a) is stored in advance in the RO, M72 in the form of a table.
and NF is 7' 00 (rpm), so INF-
When NF l=10 (rpm), ΔD is 0.02
(It can be a duck.

In step 106, the correction amount ΔD process is added to the integral term calculation of the previous routine to obtain the current DI (D process ← D process + Δ
D Engineering).

Next, in step 107, l obtained in step 104 is
The proportional term DP is extracted from the ROM 72 based on NE -NF I. For this reason, the ROM 72 is shown in Fig. 4 [b].
i=The map shown here is stored in advance in table 1 ζf. If this map is stupid, INE-NFl = 10
It is possible to set the power so that the DP is 0.5 (%) when the rotation speed is 0 (rpm). If you compare the maps in Figures 4(a) and (b), it will be clear that the maps in Figure 4(a) and (b) are the same.

In the JD engineer shown in Manofu Q Goff τ4A (a), is the straight part extending over the entire large INE-NFI range? have Therefore, it is suitable to correct the total decrease t' of ΔDIrtDX, and DP is the deviation n (missing, I NE -NF l) between the current rotation speed and the target rotation speed.
) is large, the duty ratio is quickly corrected.C
I'm doing A.

In step 108, the near conditioner is
RO in advance depending on the shift condition of the torque converter and torque converter.
There is a hanging net on A472, which is expected from the map of the Atajbj family, L
jt DT is read.

In step 109, D + DP is calculated and the 5 units are set as the learned value DG of the duty ratio (DG←D).

+DP). Then, in step 110, this learned value DG
is stored in a predetermined area of the RAM 74, and the DG of the previous routine is updated. In this way, mishap R
The learning value DG stored in AM is used during open loop control, which will be described later.

Next, in step 111, calculation of equation (1) is performed,
The determined final duty ratio Dtli is transferred to the MPU 70ρ register in step 112.

Next, to describe the arithmetic program during open loop, when it is determined in step 102 that the feedback condition is not satisfied, the process proceeds to step 1131C. In step 113, the engine cooling water temperature is set to a set value (for example, 7
0°C) or below.

If the water temperature is higher than the set value, in step 114, the learned value of the previous routine at the time of feedback is set to the current duty ratio (D←DG). In this way, by using the nfc learning value DG't recorded in RAM during feedback control as the duty ratio D during open loop control, l5CV't-learning control becomes oJ function.
Improved control during oven loop.

If the water temperature is below the set value, proceed to step 115 and D
4-DG+5 (@). In this way, 5% is added to the learning value DG.
The purpose of adding is to increase the amount of intake air when the engine is cold.

Next, in step 116, it is determined whether the starter is on or not, and if YES, the duty ratio is set to 100 t% (D←100) in step 117.

This means that l5CV50 is always open, and since the required air amount is large when the engine is started, more air is supplied. Above steps 113-1
The duty ratio obtained in step 17 is determined as M in step 112.
It is moved to the register of PU70.

Final step 11 of the duty ratio calculation routine described above
The duty ratio value stored in the register of the MPU 70 in step 2 is then used to form a pulse signal. In other words, the clock 76 is generated every unit time, which is obtained by dividing one pulse of one cycle of the pulse signal output by the register into many parts.
A clock signal is outputted to the register, and the value of the n7t duty ratio stored in the register is counted down every unit time. During this period, the register outputs an ON pulse as long as the number of registers exists, and when the register becomes zero, the ON pulse ends and one cycle of the pulse signal ends. This pulse signal is input to the drive circuit 92 via the output port 90, and the drive circuit changes the width of the pulse signal and sends it to l5CV50 in the form of a driving pulse current.
- Opening/opening 0 Therefore, the 1 drive valve's flow is the 3rd
Since we have the duty ratio calculated by the routine in the figure,
15CV is also 0N10F with the desired duty ratio.
This results in F control.

The above is the content of the desty ratio calculation program of the conventional intake air amount control device. Next, in this conventional example, how does the engine speed undershoot occur when the engine is fully revved up? 0 In this graph, on the horizontal axis representing time, the throttle valve is fully closed until time A,
It is assumed that at time A the engine starts to fully revitalize, at time S the vehicle stops and the vehicle speed is zero), at time B the throttle opening exceeds 3 degrees, and at time C the throttle opening becomes zero again. Before time B and after time C, the throttle/nottle opening is less than f13°, and therefore the idle contact of the throttle position sensor is '40N, so other feedback conditions (vehicle speed, cooling water temperature, etc.) are satisfied. If there is, feedback control is performed, but since the throttle opening exceeds 3 degrees and the idle contact is turned OFF between BC and automatic error/loop control is performed. Assuming that sufficient time has elapsed between the time when the throttle is fully closed and the time point A, the output duty ratio Dll-1: reaches a stable value due to feedback control until the time point A.
The engine speed is maintained at the target idle speed. When the throttle valve starts to open from point A due to engine revving, the amount of intake air increases and the engine speed increases. However, since feedback control is in progress up to [7.B], the output duty ratio is corrected to the closing side in order to completely reduce the engine speed according to the program described above, and the learned value DG is also updated to the closing side f' L gradually decreases. B
If the throttle opening exceeds 3°r at this point, the idle point is turned off and oven loop control is started. If, for example, the learned value DG is used as the output duty ratio during open loop control (see step 114 in Fig. 3), then the output duty ratio between j and BC is B.
This is the DG that was updated after 2 immediately before the point in time, and this DG
Since the value of fc is a throttle opening force of 3 degrees, it is significantly lower than the stable value. However, since the throttle opening degree is 3 degrees or less between B and 0, the amount of intake air will not be insufficient even if the opening degree of rscv is small. However, when the throttle valve is fully closed at time C, the desired amount of intake air that completely passes through the throttle valve becomes substantially zero, and intake air is supplied to the engine only through 15CVk. Moreover, at time C, feed pack control is started as the number 1 straight 7 departure 1' shift of the DG that was last updated just before time B, so the intake air amount becomes too small and the engine speed increases significantly. In some cases, the engine stalled.

The present invention solves the above-mentioned problems, and will now be described with reference to the flowchart of FIG. 6 of the duty ratio calculation program according to the present invention.

Step 2 (In step 11, it is determined whether the vehicle speed is below 2.5 km/h or not. If it is over 2.5 km/h, in step 210, the vehicle speed determination flag FSPDO is set to 1"?
If the engine speed is 2.5 k+/h or less (Dec), proceed to step 202. In step 202, it is determined whether the idle contact of the throttle position sensor is ON and the engine coolant temperature is 70°C or higher. case K
(Since the d feedback condition is satisfied, step 203
Proceed to the following, and if "NO", go to step 220 to determine the duty ratio during open loop control? Calculate 0 Note that step 220 id corresponds to steps 113 to 117 in the flowchart of FIG.

Steps 203-2o5u For the first time from the state with military speed i
Did the series become zero? In step 203, it is determined whether the vehicle speed determination flag FSPDO is ``1'', and if No'', the process jumps to step 207.
YES” (i.e., the vehicle speed in the previous routine was 2.5k)
m/h or more but becomes less than rn/h at 2.5 for the first time (fc), proceed to step 2J)4. Step 20
In step 4, it is determined whether the butterfly vehicle speed is zero or not. In step 204, if the vehicle speed was the same until the previous routine, but the vehicle speed is now equal to Okln/h for the first time, that is, the moment the running vehicle stops for the first time, the determination result becomes "YES".

If ``YES'', the vehicle speed determination flag Fspook is set down in step 205, and the previous learning value D is set in step 206.
The Gk reference learning value DO8 is stored in a memory consisting of a predetermined area of the RAM.In this manner, the vehicle in motion is stopped, and the learned value at the scheduled time is recorded in the memory as the reference learning value DO5. As mentioned later, is this memory ignition switch? It is preferable to use non-volatile memory that can be backed up to the environment even when the power is turned off.

Steps 207 to 214 correspond to steps 103 to 109 in the flowchart of FIG. 3, respectively, and do not require further explanation.

In step 215, a complete determination is made as to whether or not the current learning value DG calculated in step 214 is greater than I) cs -2%. If DG≧DGs−2%, proceed to step 217 and update DG k with the same value, but if DG<DGs
If s-2%, in step 216 DGs-2
The current DGk is set to the value of %, and this value is replaced with the previous learned value in step 217, thereby updating the learned value DG'. In step 218, formula (1)? The final duty ratio is then transferred to the output register in step 219.

Through the processing in step 216, the learned value DG is guarded within a predetermined range (2t6 in this example) from the standard learned value DGs, and no matter how small the value of DG calculated in step 214 is, Even if the value of DG stored in the memory in step 217 is I) Gs −
It never falls below the lower limit of 2%. Figure 5(b) shows this state, and the learned value is maintained within 2% of the standard learned value DGS at time S when the vehicle speed becomes zero (see Figure 5(a)). be. Therefore, even if the final duty ratio further decreases until reaching point B, the learned value D
G never becomes less than DGS -2%. For this reason,
Even when the throttle valve is fully closed at point C, DG
, -2L4 feedback control is started from the value of DG. Therefore, the undershoot of the rotational speed at time C can be kept to a minimum, and engine stall can be avoided.

The present invention achieves the above-mentioned effects, but when the reference learning value DGS f is recorded in the nonvolatile memory, the following effects can be obtained. In other words, the vehicle speed sensor is disconnected,
As a result, the signal from the vehicle speed sensor is always the vehicle speed Okm/hk.
If the display is displayed, feedback control will start from the moment the throttle valve is fully closed even if the vehicle speed is too high for mud removal when the vehicle is decelerating. However, during deceleration, the engine speed is higher than the target idle speed, so the duty ratio is gradually reduced by feedback control, and when the vehicle stops, the intake air amount is insufficient.
Engine stall may occur (Figure 7 (a))
. In this case, even if the starter is fully activated and the engine is restarted, the learned value DG is too small, so the duty ratio after the restart is small, causing a re-engine stall.

According to the present invention, the standard learning value DG8 is set to a predetermined range from the lower limit kDGs of the learning value (for example, +1 when guarded within 2 degrees, and even if KDG is updated during deceleration, it will not fall below the lower limit). The engine does not stall immediately after restarting (Fig. 7 (b)). However, if the engine stalls and restarts repeatedly, the standard learning value DGS is updated every time the engine is restarted, so the DGS and For example, DG decreases by 2, and finally reaches the same state as shown in FIG. Now that B is not updated in viD, the normal value before the vehicle speed sensor disconnection is stored, and the lower limit value of DG is also DGs-
Since the engine speed remains at 2'% (Fig. 7, 0), it is possible to completely avoid the danger of the engine stalling immediately after restarting.

As is clear from the above, the present invention provides a means for recording a learned value in a memory as an all-standard learning value when a running vehicle stops; Since the value is guarded within a predetermined range, the engine will not stall even if the throttle valve is fully closed after the engine is running. Furthermore, if the reference learning value is recorded in a non-volatile memory, it is possible to restart the engine when the vehicle speed sensor is broken.

[Brief explanation of the drawing]

Is the intake air amount control device in Figure 1? Figure 2 is a block diagram of the electronic control unit, Figure 3 is a flowchart of a conventional duty ratio calculation program,
FIG. 4 shows an example of a map of the correction of the integral term and the proportional term for duty conversion, and FIG. 5 shows the map of the conventional device and the present invention! ! Fluctuations in throttle opening learning value and engine speed at different locations? 6 is a flowchart of the duty ratio calculation program of the present invention, and FIG. 7 is a graph showing fluctuations in the duty ratio and learned value when the vehicle speed sensor is disconnected in comparison with fluctuations in engine speed. ...Intake pipe, 30...Electronic ft1
lJ control unit, 32...throttle valve-a4
...Throttle position sensor, 48...
...Idle speed control passage, 50...
￥ Magnetic air control - Masu (I 5CV), 62...Vehicle speed sensor. Patent Issuer Toyota Motor Corporation Patent Application Agent Patent Attorney Akira Iki Patent Attorney Kazuyuki Nishidate Patent Attorney Kyo Nakayama Patent Attorney Akira Yamaguchi 4th (0) 1 Gin stroke opening (b) Engine INF-NFI 7th ratio 5th (0) (b) Figure 7 Throttle fully closed Engine stall - Engine speed - Final duty ratio 111111 Learning value m - Reference learning value Restart

Claims (1)

[Claims] The throttle valve of the L engine is bypassed, and the bypass is set in accordance with the duty ratio VC of the N pulse signal. An on-off operating electromagnetic air control valve that fully controls the flowing and incoming air, and a pulse signal proportional to the integral term DI of the duty ratio according to the difference between the engine's target idle speed and the current idle speed. means for setting the term Dpk; means for calculating the sum of the integral term and the proportional term DP to set a learned value DGk of the duty ratio; means for recording the learned value DGk in a memory; A method α for calculating the final duty ratio during feedback control by multiplying the proportional term DP and the expected term Dr' if necessary, and oven loop control by reading the learned value from the memory and adding corrections thereto as necessary. An intake air amount control device for an internal combustion engine, comprising means for setting a final duty ratio when the engine is running, and an output means for outputting a pulse signal having the final duty ratio to an electromagnetic air control valve. Means for recording the learned value DG when the vehicle stops in another memory as a standard learned value DGs, and means for recording the learned value DG(i-
Means for limiting the reference learning value DGs to a value within a certain range? An intake air amount control device for an internal combustion engine, characterized in that: 2. The inhalation volume control device according to claim 1, wherein the memory on the side in which the reference learning value DG8 is recorded is a nonvolatile memory.