JP2000257482A - Intake control device for internal combustion engine - Google Patents

Abstract

(57) [Problem] To provide a multi-cylinder internal combustion engine having an electronically controlled on-off valve,
An excessive change in the amount of intake air when the on-off valve is opened at the end of the full-close control of the on-off valve at the time of starting is suppressed to improve the startability. SOLUTION: In an internal combustion engine having an electronically controlled on-off valve in an intake passage, the opening of the on-off valve is controlled to a first opening in a substantially fully closed state at the time of starting, and the on-off valve is brought to the first opening. Calculated the amount of air consumed by the internal combustion engine after cranking of the engine in the closed state, and based on the value of the calculated amount of air consumed, the intake passage from the downstream side of the on-off valve to just before the intake valve of each cylinder. Calculate the consumption rate of the intake air volume in the volume, and multiply this consumption rate by the required intake air volume after the valve closing control to determine the air volume at the time of transition to valve opening. The second opening degree and the first opening degree of the on-off valve for flowing the air amount are compared, and the opening degree of the on-off valve is controlled to the larger opening degree. As a result, an excessive change in the amount of intake air when the on-off valve is opened at the time of starting the engine is suppressed, and the startability of the engine is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake control device for an internal combustion engine, and more particularly, to an electronic control throttle valve having an opening which is set independently of the amount of depression of an accelerator pedal. The present invention relates to an intake control device for an internal combustion engine in which valve closing control is performed.

[0002]

2. Description of the Related Art In recent years, with the development of computers, electronically controlled internal combustion engines for electronically optimally controlling the rotation speed of internal combustion engines have been put to practical use. As electronic control of such internal combustion engines, for example, fuel injection amount control, ignition timing control, control of the opening timing of intake and exhaust valves, and the like have been preceded. You are in the stage. In an internal combustion engine that electronically controls the opening of the throttle valve, the opening of the throttle valve can be set regardless of the depression amount of the accelerator pedal.

For this reason, by closing the intake passage at the time of starting the engine using an electronically controlled throttle valve, it is possible to reduce the amount of intake air at the time of starting and to increase the intake pipe negative pressure to promote the vaporization of fuel. Proposed. This is because, in an electronically controlled internal combustion engine, fuel is not sufficiently atomized at the time of startup because fuel injection valves are installed in the intake passages near each combustion chamber, and at this time, startability deteriorates. This is in order to prevent that.

Japanese Patent Application Laid-Open No. 9-324677 discloses a technique in which the electronically controlled throttle valve is closed when the engine is started to reduce the amount of intake air and increase the negative pressure of the intake pipe to promote the fuel vaporization. There is one disclosed in Japanese Patent Publication No. Japanese Patent Application Laid-Open No. 9-324677 discloses an intake control apparatus for an internal combustion engine which includes a control means for closing an intake passage with a throttle valve when the engine is started, and opening the throttle valve after the start of the engine is completed. The elapsed time after the start of fuel injection at the time of starting the engine is measured, and when the elapsed time exceeds a predetermined time, the throttle valve is opened to a predetermined opening even before the start of the engine is completed, and the fuel injection amount is reduced. It is disclosed that the dose is increased.

[0005]

However, according to the technique disclosed in Japanese Patent Application Laid-Open No. 9-324677, when the throttle valve is opened, if the opening degree of the throttle valve changes greatly, the change in the intake air amount becomes large, and the air becomes empty. There has been a problem that the fuel ratio control cannot follow, which affects the startability and causes deterioration of emission.

Accordingly, the present invention relates to a multi-cylinder internal combustion engine in which an electronically controlled on-off valve is provided in an intake passage, wherein the electronically controlled on-off valve is controlled to be closed when the engine is started.
At the time of transition from valve closing control to valve opening control of the electronically controlled on-off valve,
It is an object of the present invention to provide an intake control device for an internal combustion engine, which can suppress an excessive change in intake air amount, improve startability of the engine, and prevent emission deterioration.

[0007]

According to a first aspect of the present invention, an electronic control on-off valve is operated at the time of starting to close an intake passage, and the intake pipe negative pressure at the time of starting is increased. In an intake control device for an internal combustion engine that performs valve closing control at the time of startup for atomization of fuel, when the ignition switch is turned on, the opening degree of the electronically controlled on-off valve is fully closed leaving a slight gap between the opening and the intake passage. First opening degree control means for controlling the opening degree to a first degree close to the state, and consumption of the internal combustion engine after the engine is cranked with the on-off valve at the first degree of opening. Means for calculating the amount of consumed air for calculating the amount of consumed air, and the value of the amount of consumed air and the amount of intake air in the volume of the intake passage from the downstream side of the electronically controlled on-off valve to the position before the intake valve of each cylinder. The transfer coefficient from the intake air consumption rate based on the Transition coefficient calculating means, a transition air amount calculating means for calculating a transition air amount from an intake air amount and a transition coefficient required after the valve closing control at the start is completed, and a transition air amount A second opening control means for comparing the second opening degree and the first opening degree of the on-off valve for flowing the air, and controlling the opening degree of the on-off valve to the larger opening degree. It is characterized by.

According to a second aspect of the present invention for achieving the above object, in the first aspect of the present invention, the second opening control means is provided when the elapsed time after the start of the engine exceeds a predetermined time. The operation is stopped. Note that the gap at the first opening degree described above can be a gap that can ensure the minimum idle air flow rate value. In addition, the valve closing control at the time of starting according to the present invention is performed when the engine temperature is within the predetermined temperature range. It can be activated only at certain times.

According to the present invention, when opening the electronically controlled on-off valve which is closed when the engine is started, the opening degree of the electronically controlled on-off valve is determined by the transition coefficient based on the consumption ratio of the intake air amount and the starting coefficient. When the transition from the valve-closing control to the valve-opening control is performed, an excessive change in the amount of intake air can be suppressed. Startability is improved, and deterioration of emission is prevented.

[0010]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 schematically shows an electronically controlled fuel injection type multi-cylinder internal combustion engine 1 including an intake control device according to one embodiment of the present invention. In FIG. 1, a throttle valve 3 is provided in an intake passage 2 of an internal combustion engine 1 downstream of an air cleaner (not shown). One end of a shaft of the throttle valve 3 is a throttle as an actuator for driving the throttle valve 3. A motor 4 is provided, and a throttle opening sensor 5 for detecting the opening of the throttle valve 3 is provided at the other end. That is, the throttle valve 3 of this embodiment detects the opening of the accelerator pedal 14 with the accelerator opening sensor 15 and combines the opening with the ECU (to be described later) together with the control signal of the electronic control device attached to the engine. The engine control unit (10) determines an optimum throttle opening and is incorporated in an electronically controlled throttle (hereinafter simply referred to as an electronic throttle) driven to be opened and closed by the throttle motor 4. With electronic throttle, throttle valve 3
When the opening command value is input from the ECU 10, the throttle motor 4 causes the throttle valve 3 to follow the command opening in response to the command value.

An atmospheric pressure sensor 18 is located upstream of the throttle valve 3 in the intake passage 2 and a surge tank 6 is located downstream. In the surge tank 6, a pressure sensor 7 for detecting the pressure of intake air is provided. Furthermore, surge tank 6
A fuel injection valve 8 for supplying pressurized fuel from a fuel supply system to an intake port is provided for each cylinder. The output of the throttle opening sensor 5 and the output of the pressure sensor 7 are input to an ECU 10 incorporating a microcomputer.

In the cooling water passage 9 of the cylinder block of the internal combustion engine 1, a water temperature sensor 11 for detecting the temperature of the cooling water is provided. The water temperature sensor 11 generates an analog voltage electric signal according to the temperature of the cooling water. The exhaust passage 12 contains three harmful components HC and C in the exhaust gas.
A three-way catalytic converter (not shown) for purifying O and NOx at the same time is provided. An O ₂ sensor 13 which is a kind of air-fuel ratio sensor is provided in an exhaust passage 12 on the upstream side of the catalytic converter. I have. The O ₂ sensor 13 generates an electric signal according to the concentration of the oxygen component in the exhaust gas. The outputs of the water temperature sensor 11 and the O ₂ sensor 13 are
Is input to

The ECU 10 further includes an accelerator pedal depression amount signal (accelerator opening signal) from an accelerator opening sensor 15 and a key position signal (accessory position, accessory position) from an ignition switch 17 connected to a battery 16.
ON position, starter position), a top dead center signal TDC from a crank position sensor 21 provided near a timing rotor 24 integrated with a crankshaft timing pulley attached to one end of the crankshaft, and a crank at a predetermined angle. The angle signal CA and the temperature of the lubricating oil from the oil temperature sensor 22 are input. The ring gear 23 provided at the other end of the crankshaft is rotated by the starter 19 when the engine 1 starts.

The engine speed Ne is determined by a predetermined crank angle signal C.
It is obtained by measuring the interval (time) of A. The timing rotor 24 is provided with signal teeth 25, and has 34 teeth having two missing tooth portions 26 for detecting the top dead center. The crank position sensor 21 can be composed of an electromagnetic pickup and outputs a crank rotation signal every 10 °. The crank position sensor 21 can detect an accurate top dead center by detecting a signal at the position of the missing tooth portion 26. The cylinder in which the fuel injection of the internal combustion engine is executed can be determined by the signal from the crank position sensor 21 and the signal from a cam position sensor (not shown).

In a conventional internal combustion engine, a starter 19 generally composed of a DC series motor is connected to a battery 16 via a starter switch which is turned on when an ignition switch 17 is set to a starter position. Therefore, when the ignition switch 17 is turned on and the ignition switch 17 is thereafter set to the starter position, the starter 19 is activated and the engine 1 is activated. When the engine 1 starts operating, the ECU 10 is energized to start a program, take in the output from each sensor, and control the throttle motor 4, the fuel injection valve 8, which opens and closes the throttle valve 3, the fuel injection valve 8, and other actuators. . The ECU 10 includes an A / D converter for converting an analog signal from various sensors into a digital signal.
1. CPU 102 for performing arithmetic processing, ROM 103 or RA
A memory such as M104, a clock 105, and the like are provided, and these are mutually connected by a bus 106. E
Since the configuration of the CU 10 is known, further description is omitted.

On the other hand, in this embodiment, the starter 19 is not directly connected to the battery 16, but is connected to the battery 16 via a starter drive circuit 20. And
The starter drive circuit 20 switches the starter 19 to the battery 1 when the starter signal ST from the ECU 10 is not input.
6 is not connected. In this embodiment, when the engine 1 is started, the throttle valve 3 is temporarily closed to substantially close the intake passage 2, and a negative pressure is generated downstream of the throttle valve 3 to improve the startability of the engine. I have. On the other hand, when the engine 1 is stopped, the throttle valve 3 is not in the fully closed position but is slightly open. Therefore, when the engine 1 is stopped, the pressure in the intake passage 2 of the throttle valve 3 is at the atmospheric pressure.

Therefore, when starting the engine 1, it is necessary to drive the throttle motor 4 to control the throttle valve 3 to the fully closed position. The throttle valve 3 here
The fully closed position 3 is a position where the throttle valve 3 and the intake passage 2 do not collide with each other but a gap is slightly opened. In this embodiment, the gap is such that the minimum ISC flow rate ISCmin The gap is just enough to flow. Therefore, E
The CU 10 has the ignition switch 1 as described above.
7 and a throttle opening signal from the throttle opening sensor 5 are input.

Here, the procedure of the drive control of the throttle valve 3 and the fuel injection control executed by the ECU 10 at the time of starting the engine 1 constructed as described above will be described with reference to the flowcharts of FIGS. This will be described with reference to FIG.
FIG. 2 is a flowchart showing a procedure for setting a flag FTHVC for executing the closing control of the electronic control throttle valve 3.
The routine shown in FIG. 2 is executed at a predetermined time, for example, every several ms in the initial routine only when the engine 1 is started.

In this control, first, at step 201, the engine coolant temperature THW detected by the coolant temperature sensor 11 described with reference to FIG. 1 is read. In the following step 202, it is determined whether or not this water temperature is in a range of a predetermined temperature A ° C. to B ° C. If the water temperature THW is not in this range, step 20 is executed.
Then, the program proceeds to 4, the throttle valve closing control execution flag FTHVC is set to "0", and this routine ends. On the other hand, the water temperature TH
When W is within this range, the routine proceeds to step 203, where the throttle valve closing control execution flag FTHVC is set to "1".
To end this routine. When the throttle valve closing control execution flag FTHVC is "1", it indicates that the closing control of the throttle valve is performed.

In this embodiment, the throttle valve closing control execution flag FTHVC is set to "0" when the water temperature THW is less than the extremely low temperature A.degree. C. and exceeds the extremely high temperature B.degree. However, this is to increase the reliability of the engine startability at the present time, and if the control accuracy is increased by increasing the cost, the throttle valve closing control at the time of starting the engine will not be performed. It is also possible to carry out independently of the water temperature conditions.

Thus, when the engine 1 is started, the water temperature TH
When W is in the range of A ≦ THW ≦ B, the throttle valve closing control execution flag FTHVC set to “1” indicates that the engine 1
Is reset after a predetermined time from the start of the vehicle. The reset time of the throttle valve closing control execution flag FTHVC can be set, for example, in consideration of the time when the air amount downstream of the throttle valve when the throttle valve is closed disappears after the engine is started. This control will be described with reference to the flowchart shown in FIG. The routine shown in FIG. 3 is also executed every predetermined time, for example, every several ms in the initial routine only when the engine 1 is started.

In this control, first, at step 301, the engine speed Ne is read. The engine speed Ne is shown in FIG.
Can be calculated from the crank position signal from the crank position sensor 21 shown in FIG. In the following step 302, the engine speed Ne read in step 301
Is determined to be not less than the set rotation speed Nes, for example, not less than 400 rpm. If the engine speed Ne is less than the set speed Nes, it is determined that the engine has not started yet, and the routine proceeds to step 303, where the value of the elapsed time after engine start counter CNT is cleared, and this routine ends.

On the other hand, if the engine speed Ne is equal to or higher than the set speed Nes in step 302, it is determined that the engine has started, and the routine proceeds to step 304, where the value of the post-start elapsed time counter CNT is incremented by one, and 30
Go to 5. In step 305, it is determined whether or not the value of the post-start elapsed time counter CNT has reached a reference count value C indicating a predetermined time. Then, the post-start elapsed time counter CNT
Is smaller than the reference count value C, the routine is terminated as it is. If the value of the post-start elapsed time counter CNT reaches the reference count value C, the routine proceeds to step 306, where the throttle valve closing control execution flag FTHVC is executed. Is set to "0", and this routine ends. In this manner, the throttle valve closing control execution flag F, which was "1" when the engine was started,
THVC is set to “0” when a predetermined time has elapsed since the start of the engine.

FIG. 4 shows that when the engine 1 is cranked and started after the throttle valve 3 is fully closed when the engine 1 is started, the throttle valve 3 of the intake passage 2 in this embodiment is used.
FIG. 7 is a characteristic diagram showing an air consumption ratio R of the intake system when the air in the volume Vvol on the downstream side of the intake air decreases with time. The air consumption ratio R of the intake system in this embodiment is a value obtained by dividing the integrated air consumption ΣU consumed by the internal combustion engine 1 by the air amount Vvol of the intake system. When the integrated air consumption ΣU is small, R is 0. And the accumulated air consumption ΣU
As R increases, R gradually increases and approaches 1. That is,
The air consumption ratio R of the intake system in this embodiment is 0 ≦ R ≦
Since it is a value of 1 and is used like a coefficient hereinafter, the intake system air consumption ratio R is referred to as a transition coefficient here.

When the engine 1 is started, the driver sets the ignition switch 17 to the starter position,
When the operation of depressing the accelerator pedal is performed, in an internal combustion engine not equipped with an electronic throttle, the engine speed increases in accordance with the amount of depression of the accelerator pedal at the time of starting. On the other hand, in an internal combustion engine equipped with an electronically controlled throttle as in the present invention, it is possible to control the rotation speed of the internal combustion engine when the engine 1 starts, regardless of the amount of depression of the accelerator pedal by the driver.

As a result, in the present invention, when the engine 1 is cranked and started after the throttle valve 3 is fully closed as shown in FIG. Can be calculated in advance, and this can be stored in the ROM 103 of the ECU 10. Actually, the characteristic that the air corresponding to the volume Vvol on the downstream side of the throttle valve 3 that is closed at the time of starting decreases with time is a known value because the rotation speed of the engine 1 is controlled by the ECU 10. ) And the volume efficiency ηv used for calculating the air consumption calculated from the rotation speed map of the engine 1 (indicating how much air was sucked in with respect to the volume of the combustion chamber. The smaller the value, the smaller the value.) That is,
The amount of air (consumed air amount) U sucked into the combustion chamber for each revolution of the engine 1 after the engine is started can be obtained from the equation, U = ηv × Vd × １ ／, and is obtained by integrating these. The transfer coefficient R can be obtained from the accumulated air consumption ΣU after the start of the start.

FIG. 5 is a flowchart showing an embodiment of a procedure for setting the opening of the electronically controlled throttle valve 3 when the engine 1 is started. The routine shown in FIG.
It is executed every few ms. In this embodiment, first, at step 501, the throttle valve closing control execution flag FTH
Read the value of VC. In the following step 502, it is determined whether or not the value of the throttle valve closing control execution flag FTHVC is "1".

If it is determined in step 502 that the value of the throttle valve closing control execution flag FTHVC is "0", it is determined that the start of the engine 1 has been completed and step 5
Go to 03. At step 503, the value of the time counter T is cleared, and the routine proceeds to step 504. In step 504, a normal ISC flow rate ISCN is calculated by a normal calculation formula. The normal calculation formula is a learning value of the ISC flow rate, a correction value based on the water temperature, a correction value of the ISC flow rate at the time of starting, a correction value based on ON / OFF of the air conditioner, a correction value based on the presence or absence of the electric load, and a correction value based on the presence or absence of the power steering. This is an equation for correcting with a correction value or the like due to operation. In the following step 505, the throttle valve opening θthv corresponding to the normal ISC flow rate ISCN calculated in step 504 is set as the throttle valve opening, and this routine ends. Since the control when the start of the engine is completed is not the gist of the present invention, further description will be omitted.

On the other hand, if it is determined in step 502 that the value of the throttle valve closing control execution flag FTHVC is "1", it is determined that the engine 1 is being started, and the routine proceeds to step 506. In step 506, the starter signal ST
Is determined to be 1, that is, whether or not the intake air is being sucked into the combustion chamber of the engine 1. When the intake air is not sucked into the combustion chamber, this routine is terminated.
Step 5 when the intake air is being sucked into the combustion chamber
Proceed to 07.

In step 507, the value of the time counter T is incremented to calculate an integrated time during which the engine is drawing air. In the next step 508, it is determined whether or not the cylinder determination of the engine after the engine 1 has been cranked has been completed. If it is determined in step 508 that the cylinder determination has not been completed, the process proceeds to step 509,
Throttle valve opening θ to flow minimum ISC flow ISCmin
th1 is set as the throttle valve opening, and this routine ends.

On the other hand, if it is determined in step 508 that the cylinder discrimination has been completed, the flow proceeds to step 510. Step 5
At 10, the transition coefficient (intake system air consumption ratio) R corresponding to the value of the time counter T calculated at step 507 is calculated by the ECU.
Is read from the ROM 103. In the following step 511, the normal ISC flow rate ISCN is calculated by the normal calculation formula in the same manner as calculated in step 504, and the normal flow rate ISCN is multiplied by the transfer coefficient R calculated in step 510 to obtain the transfer air amount ISCN. * Calculate R.

In step 512, the minimum ISC flow rate IS
Cmin and the transition air amount ISC calculated in step 511
Compare the magnitude with N * R. And ISCmin ≧ IS
In the case of CN * R, the routine proceeds to step 509, in which the opening degree θth at which the minimum ISC flow rate ISCmin flows as the throttle valve opening degree
Set 1 to end this routine. On the other hand, if ISCmin <ISCN * R in step 512, the process proceeds to step 513, in which the throttle valve opening θth2 through which the transition air amount ISCN * R flows is set, and this routine ends.

As described with reference to FIG. 4, after the cranking of the engine 1 is started, the value of the transition coefficient R gradually increases and approaches 1 as the count value of the time counter T increases. Therefore, the value of the throttle valve opening θth2 set in step 513 gradually increases, and finally becomes the normal ISC flow rate ISCH calculated in step 505.

FIG. 6 shows a starter signal, a throttle valve closing control execution flag FTHVC, a cylinder discrimination signal, a counter CNT after engine start, an engine speed Ne,
4 is a time chart showing changes in an ISC flow rate and a throttle valve opening degree θth. When the value of the starter signal becomes 1 and the engine is started at time T0 when the throttle valve closing control execution flag FTHVC is "1", the value of the cylinder discrimination signal is 0 at this time, The valve opening θth is set to the first opening θth1. Thereafter, during cranking until time T1, the necessary minimum ISC flow rate ISCmi while the throttle valve 3 is kept at the substantially full-closed opening degree θth1.
n flows.

When the cylinder discrimination is performed at time T1 during cranking of the engine, the necessary minimum ISC flow rate ISC
A comparison is made between min and the transition air amount ISCN * R. Until time T2, ISCmin ≧ ISCN
Since * R, the throttle valve opening is set to the opening θth1 at which the minimum ISC flow ISCmin flows. On the other hand, when ISCmin <ISCN * R at time T2, the opening degree of the throttle valve opening at which the transition air amount ISCN * R flows is θ.
Set to th2.

In this example, cranking is continued for a predetermined time from time T0, the engine is started at a time after time T1 and before time T2, and the engine speed Ne increases after the engine is started. When the engine speed Ne reaches the predetermined speed Nes at time T3 after time T2, the counter CNT starts counting after the engine is started. Time T
After 2, the value of the throttle valve opening θth2 gradually increases as the value of the transition coefficient R increases, as described with reference to FIG.
With this, the ISC flow rate also increased, and gradually the normal ISC
Flow rate approaching ISCH.

In this embodiment, when the after-engine start counter CNT reaches the predetermined value C at time T4 and the throttle valve closing control execution flag FTHVC is set to "0", the value of the transition coefficient R increases and the throttle valve As the opening degree θth2 increases, the ISC flow rate has also reached the vicinity of the normal ISC flow rate ISCH. As described above, the value of the counter CNT after the engine starts near the time when the ISC flow reaches the vicinity of the normal ISC flow ISCH due to the increase of the throttle valve opening θth2 is set to the predetermined value C.
In this case, the throttle valve opening θth2 at the end of the execution of the throttle valve closing control is close to the throttle valve opening θthv based on the normal calculation formula. , The change in the intake air amount can be suppressed to a small value.

As described above, in the present invention, as described in the embodiment, in the multi-cylinder internal combustion engine which performs the closing control of the throttle valve at the time of starting the engine, the minimum I after the cylinder discrimination is obtained.
By comparing the SC flow ISCmin and the transition air amount ISCN * R, and adjusting the opening of the throttle valve so that the larger ISC flow flows, the electronic control on / off valve is closed and then opened. At the time of the transition to the control, an excessive change in the intake air amount can be suppressed, so that the startability of the engine can be improved and emission deterioration can be prevented.

In the embodiment described above, the minimum I
The comparison between the SC flow rate ISCmin and the transition air amount ISCN * R is performed after the cylinder discrimination. It may be performed after a predetermined time has elapsed. In the embodiment described above,
The description has been given of the case where the electronic control throttle valve 3 is used to close the intake passage of the internal combustion engine. The present invention can also be applied effectively.

[0040]

As described above, according to the intake control apparatus for an internal combustion engine of the present invention, a multi-cylinder internal combustion engine in which an electronically controlled on-off valve is provided in an intake passage, and the electronic control is performed when the engine is started. In the control that performs on-off control of the on-off valve, it is possible to suppress an excessive change in the intake air amount when shifting from the close control of the electronic control on-off valve to the valve opening control, thereby improving the startability of the engine and deteriorating the emission. This has the effect that the prevention of the occurrence can be realized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a configuration of an electronically controlled multi-cylinder internal combustion engine equipped with an intake control device according to one embodiment of the present invention.

FIG. 2 is a flowchart showing a procedure for setting a flag for executing a throttle valve closing control.

FIG. 3 is a flowchart illustrating resetting of a flag for executing a throttle valve closing control.

FIG. 4 is a characteristic diagram showing a change in intake air consumption ratio with time.

FIG. 5 is a flowchart showing an embodiment of a procedure for setting the opening of the electronically controlled throttle valve at the time of starting according to the present invention.

FIG. 6 is a time chart showing transitions of a starter signal, a throttle valve closing control execution flag, a cylinder discrimination signal, a counter after engine start, an engine speed, an ISC flow rate, and a throttle valve opening degree in the embodiment of the present invention.

[Explanation of symbols]

 2 ... intake passage 3 ... throttle valve 4 ... throttle motor 5 ... throttle opening sensor 8 ... fuel injection valve 10 ... ECU 17 ... ignition switch 18 ... atmospheric pressure sensor 19 ... starter 20 ... starter drive circuit 21 ... crank position sensor 23 ... Ring gear 24 ... Timing rotor 25 ... Signal tooth 26 ... Tooth missing part

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Satoshi Watanabe 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation F-term (reference) 3G065 AA04 CA00 CA12 DA05 EA01 GA01 GA09 GA10 GA26 GA35 GA37 GA41 GA46 3G301 HA06 JA00 JA21 KA01 KA10 LA03 LA04 NE23 PA07Z PA09Z PA11Z PD03Z PE01Z PE03Z PE05Z PE08Z PF03Z PF13Z PF14Z PF16Z

Claims (2)

[Claims] An intake control device for an internal combustion engine that performs a valve closing control at a start time by activating an electronic control on / off valve at a start to close an intake passage, wherein the electronic control opening and closing is performed when an ignition switch is turned on. First opening control means for controlling the opening of the valve to a first opening close to a fully closed state that leaves a slight gap between the valve and the intake passage; Means for calculating the amount of consumed air consumed by the internal combustion engine after cranking of the engine is performed in a state where the engine is turned off, and intake air of each cylinder from the downstream side of the electronically controlled on-off valve. A transition coefficient calculating means for calculating a transition coefficient from an intake air amount in the volume of the intake passage up to the valve and a consumption ratio of the intake air amount based on the value of the consumed air amount; Required intake air volume after valve closing control is completed A transition air amount calculating means for calculating a transition air amount from the transition coefficient; and comparing a second opening degree and the first opening degree of the on-off valve for flowing the transition air amount. And a second opening control means for controlling the opening of the on-off valve to the larger opening. An air intake control device for an internal combustion engine, comprising: 2. The intake control device for an internal combustion engine according to claim 1, wherein the second opening control means stops operation when an elapsed time after the start of the engine exceeds a predetermined time. An intake control device for an internal combustion engine.