JP4543589B2 - Intake control device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an intake control device for an internal combustion engine.
[0002]
[Prior art]
In general, in an in-vehicle internal combustion engine such as an automobile engine, an air-fuel mixture is formed by mixing intake air sucked into a combustion chamber through an intake passage and fuel injected from a fuel injection valve. Driving power is obtained by burning in the combustion chamber. Further, a throttle valve for adjusting the amount of intake air taken into the combustion chamber is provided in the intake passage of such an internal combustion engine, and the output of the internal combustion engine is adjusted through the adjustment of the intake air amount by the throttle valve. Will be adjusted. In recent years, even during idling of the engine, a device for controlling the rotational speed at that time, that is, the idling rotational speed to a target rotational speed through the throttle valve has been put into practical use. In such a device, the opening degree of the throttle valve is usually electrically controlled by a motor or the like.
[0003]
By the way, in the internal combustion engine, carbides and oxides such as fuel and lubricating oil, so-called deposits may adhere to or accumulate on the inner wall surface of the intake passage. When deposits adhere or accumulate in this way, the effective cross-sectional area of the intake passage is reduced. Therefore, when the throttle valve opening is the same, if the deposit adheres to or accumulates on the inner wall surface, the amount of air sucked into the combustion chamber is reduced compared to the state without the deposit. In addition, the amount of air-fuel mixture charged in the combustion chamber is reduced. In particular, such a device that controls the idle rotation speed by means of a throttle valve as in the above-mentioned device is also a serious problem, and the amount of intake air decreases during idle operation in which the throttle valve is close to a fully closed state. As a result, the idling speed is likely to become unstable, causing vibrations that are uncomfortable for the vehicle occupant and engine stalling.
[0004]
Therefore, conventionally, when controlling the idle rotation speed, the opening degree of the throttle valve is corrected according to the excess or deficiency of the intake air amount with respect to the target rotation speed, and the electronic control unit uses the excess or deficiency of the intake air amount as a learning value. (ECU) It memorize | stores in an internal memory and copes with the time-dependent change of the intake passage resulting from the deposit by performing opening degree correction of the throttle valve based on the memorized value.
[0005]
[Problems to be solved by the invention]
By the way, for example, when the power supply from the battery to the ECU stops, the learning value stored in the internal memory is inadvertently initialized, and the opening of the throttle valve is set to the internal combustion engine. May not be able to be set to a value suitable for starting. At this time, if the deposit adheres to or accumulates on the inner wall surface of the intake passage, the intake air amount necessary for starting the engine may not be secured. If the necessary intake air amount cannot be ensured in this way, the engine is stopped immediately after the internal combustion engine is started.
[0006]
The present invention has been made in view of the above circumstances, and an object thereof is to detect a reason for a change in the intake air amount during idle operation and to learn a change amount in the intake air according to the reason for the change. Therefore, an object of the present invention is to provide an intake control device for an internal combustion engine that can set an idle rotation speed to a predetermined rotation speed.
[0007]
[Means for Solving the Problems]
The means for achieving the above object and the effects thereof will be described below.
According to the first aspect of the present invention, the idle rotational speed of the internal combustion engine is adjusted to a predetermined rotational speed by adjusting the idle opening of the throttle valve provided in the intake passage of the internal combustion engine based on the learned value of the intake air amount. In the intake control device for an internal combustion engine provided with a control means for feedback control so as to satisfy the first learning means for learning the change in the intake air amount with respect to the idle opening of the throttle valve, and the first learning means A flow rate change reason detecting means for detecting whether or not a learning value has been initialized; a second learning means for learning a change in the intake air amount with respect to an idle opening of the throttle valve in accordance with the initialization of the learning value ; It is a summary to provide.
[0008]
According to the first aspect of the present invention, the change in the intake air amount with respect to the idle opening of the throttle valve caused by the change over time, such as the accumulation of the deposit as described above on the inner wall surface of the intake passage, is the first learning means. And the idle opening of the throttle valve is adjusted based on the learned value. It is detected whether or not the learning value by the first learning means has been initialized, and the change in the intake air amount with respect to the idle opening is learned by the second learning means in accordance with the initialization of the learning value . By adjusting the idle opening of the throttle valve based on the learning value of the second learning means, the deviation of the idle rotation speed from the predetermined rotation speed is reduced.
[0009]
According to a second aspect of the present invention, in the intake control device for an internal combustion engine according to the first aspect, the flow rate change reason detecting means is configured to detect the first learning means based on the interruption of the power supply from the battery. The gist is that the learning value is detected to be initialized.
[0010]
According to the second aspect of the present invention, the first learning means learns a change in the intake air amount caused by a change over time such as deposit accumulation on the inner wall surface of the intake passage. Will be initialized based on the interruption of the power supply from. When the throttle valve idle opening is adjusted based on such a learning initial value, since deposits are accumulated in the intake passage, the amount of intake air is a necessary intake for setting the idle rotation speed to a predetermined rotation speed. It becomes possible to detect that the amount of air has become less.
[0011]
According to a third aspect of the present invention, in the intake control device for an internal combustion engine according to the second aspect, the second learning means raises a predetermined amount with respect to the learning initial value of the intake air amount. It is a summary.
[0012]
According to the third aspect of the invention, the second learning means raises the intake air amount by a predetermined amount with respect to the learning initial value of the intake air amount, and the throttle valve idle opening degree is based on the raised learning value. Will be adjusted. Therefore, the intake air amount can be set to a necessary intake air amount for changing the idle rotation speed to a predetermined rotation speed, and the start of the internal combustion engine can be ensured. In this case, since the start of the internal combustion engine is ensured in this way, learning by the first learning means is newly resumed, and thereafter, engine operation based on the new learning value by the first learning means is ensured. Will come to be.
[0013]
According to a fourth aspect of the present invention, the idle rotational speed of the internal combustion engine is adjusted to a predetermined rotational speed by adjusting an idle opening degree of a throttle valve provided in an intake passage of the internal combustion engine based on a learned value of an intake air amount. In the intake control apparatus for an internal combustion engine provided with a control means for performing feedback control so as to satisfy the first learning means for learning the change of the intake air amount with respect to the idle opening of the throttle valve, the throttle valve in the intake passage A flow rate change reason detecting means for detecting that deposits adhering to the vicinity have been removed, and learning a change in intake air amount with respect to an idle opening of the throttle valve in response to detection of removal of the deposits. And a learning means .
[0014]
According to the fourth aspect of the present invention, the first learning means learns a change in the intake air amount caused by a change over time such as deposit accumulation on the inner wall surface of the intake passage, and the throttle is determined based on the learned value. The idle opening of the valve is adjusted. At this time, if the deposit adhering to the vicinity of the throttle valve is removed, it can be detected that the intake air amount exceeds the necessary intake air amount for setting the idle rotation speed to the predetermined rotation speed. The idle rotation speed will be higher than the predetermined rotation speed.
[0015]
According to a fifth aspect of the present invention, in the intake control device for an internal combustion engine according to the fourth aspect, the second learning means is based on a learning value of the intake air amount learned by the first learning means. The gist is to reduce the predetermined amount.
[0016]
According to the invention described in claim 5, the predetermined amount is reduced from the learning value of the first learning means, and the idle opening of the throttle valve is adjusted based on the reduced learning value. . Therefore, the intake air amount can be set to a necessary intake air amount for setting the idle rotation speed to the predetermined rotation speed, and an increase in the idle rotation speed of the internal combustion engine from the predetermined rotation speed can be suppressed.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
Hereinafter, a first embodiment of an intake air control apparatus for an internal combustion engine according to the present invention will be described in detail with reference to FIGS.
[0018]
FIG. 1 shows a schematic configuration of an internal combustion engine provided with an intake control device of the present embodiment. An engine 10 mounted on a vehicle (not shown) includes a cylinder block 12 having a cylinder bore 11 and a cylinder head 13. A piston 14 is provided in the cylinder bore 11 so as to be able to reciprocate, and a combustion chamber 15 is formed by a space surrounded by the piston 14 and the cylinder head 13.
[0019]
The cylinder head 13 is provided with a spark plug 16 corresponding to each combustion chamber 15. The cylinder head 13 is provided with an intake port 17 and an exhaust port 18 that communicate with the combustion chambers 15, and an intake passage 19 and an exhaust passage 20 are connected to the ports 17 and 18, respectively. An intake valve 21 and an exhaust valve 22 are provided at each open end of the intake port 17 and the exhaust port 18 that communicate with the combustion chamber 15. Each valve 21 and 22 is opened and closed by a camshaft (not shown) interlocked with the rotation of a crankshaft (not shown). Further, in the vicinity of the intake port 17, an injector 23 for fuel injection is provided corresponding to each cylinder. Each injector 23 is supplied with fuel at a predetermined pressure from a fuel tank (not shown) by a fuel pump (not shown).
[0020]
An electronically controlled throttle valve (hereinafter simply referred to as “throttle valve”) 24 for adjusting the amount of intake air into the combustion chamber 15 is provided in the middle of the intake passage 19. The throttle valve 24 is controlled to be opened and closed by a motor 25, and the motor 25 is electrically driven by an output signal from an electronic control unit (ECU) 40 described later. The opening degree of the throttle valve 24 is monitored by a throttle sensor 25a, and the monitoring result is taken into the ECU 40.
[0021]
On the other hand, the ignition signal distributed by the distributor 26 is applied to the spark plug 16 provided for each cylinder of the engine 10. The distributor 26 distributes the high voltage output from the igniter 27 to each spark plug 16 in synchronization with the rotation of the crankshaft. The ignition timing of each spark plug 16 is determined by the timing at which a high voltage is output from the igniter 27.
[0022]
The distributor 26 incorporates a rotor (not shown) that rotates in conjunction with the rotation of the crankshaft. The distributor 26 is provided with a rotation speed sensor 28 for detecting the rotation speed N of the engine 10 from the rotation of the rotor. A vehicle speed sensor 29 is provided in an automatic transmission (not shown) that is drivingly connected to the engine 10. The vehicle speed sensor 29 detects the vehicle speed (vehicle speed) at that time, and outputs a signal indicating the value. The accelerator pedal 30 is provided with an accelerator sensor 31a that outputs a signal corresponding to the amount of depression, together with an accelerator switch 31 that is turned on when the accelerator pedal 30 is depressed.
[0023]
The ECU 40 includes a central processing unit (CPU) that executes processes related to various controls, a read-only memory (ROM) that stores a predetermined control program and the like, and a random access memory (RAM that temporarily stores calculation results and the like of the CPU) ), A backup RAM for storing stored data, a counter, and the like, and a logical operation circuit in which these units are connected to an external input circuit and an external output circuit by a bus.
[0024]
In addition to the throttle sensor 25a, the rotational speed sensor 28, the vehicle speed sensor 29, the accelerator switch 31, and the accelerator sensor 31a, the external input circuit includes a water temperature sensor 32 that detects the temperature of the coolant of the engine 10, that is, the coolant temperature. Electrically connected. In addition to the motor 25, an injector 23 and an igniter 27 are electrically connected to the external output circuit. The CPU inputs output signals from the sensors 25a, 28, 29, 32, 31a, the accelerator switch 31 and the like via an external input circuit, and performs idle speed control control (hereinafter referred to as “ISC control”) of the engine 10 and the like. Perform various controls.
[0025]
Here, the ISC control will be described.
This ISC control is performed when the engine 10 is idling, and the opening degree of the throttle valve 24 according to whether the intake air amount is excessive or insufficient so that the rotation speed N during the idling operation matches the target idle rotation speed Nt. This is performed by correcting TA to the target opening degree TAt. Further, the excess or deficiency of the intake air amount with respect to the target idle rotation speed from the initial intake air amount is stored as a learned value in the RAM or backup RAM of the ECU 40 at a predetermined timing. The initial intake air amount is the intake air amount necessary for obtaining the target idle rotation speed in a state where no deposit is accumulated in the intake passage 19. The ECU 40 corrects the opening of the throttle valve 24 based on the stored learned value of the intake air amount so as to cope with the time-dependent change of the intake passage caused by the deposit.
[0026]
As described above, for example, when the power supply from the battery (not shown) to the ECU 40 is stopped, the stored learned value of the intake air amount is inadvertently initialized, and the throttle valve 24 is inadvertently initialized. May not be set to a value suitable for starting the engine 10. At this time, if the deposit is deposited on the inner wall surface of the intake passage 19, it stops immediately after the internal combustion engine is started, and it becomes difficult to maintain the operating state of the engine 10.
[0027]
Therefore, in the present embodiment, each time the engine 10 is started, each time a stall of the engine 10 is detected, the reason for the change in the intake air amount is that the power supply of the battery is stopped and the learned value of the intake air amount is initialized. Whether or not the intake air amount with respect to the idle opening of the throttle valve 24 is learned according to the reason for the change in flow rate.
[0028]
Next, the learning control routine executed by the ECU 40 will be described in detail according to the flowchart shown in FIG. This routine is executed every time the engine 10 is started.
[0029]
As shown in FIG. 2, when the process proceeds to this routine, first, at step 100, it is determined whether the engine 10 has been started but stalled based on the following plurality of conditions. This condition is (1) the cooling water temperature is a predetermined value or more,
(2) There is a starter operation history,
(3) The ignition switch is ON,
(4) The learning value increase determination time is less than the predetermined value, that is, the time for determining whether or not the flow rate learning value may be raised is less than the predetermined value.
(5) The engine stall is being determined, that is, there is a starter operation history and the engine speed is less than a predetermined value,
(6) The number of corrections for raising the learning value is not more than the maximum number,
(7) There is an engine start history, that is, a history that the engine rotational speed exceeds a predetermined rotational speed,
(8) Before completion of learning of the intake air amount. If all these conditions are met, it is determined that the engine 10 has started but has stalled. That is, it is determined that the engine 10 has stalled because the intake air amount is insufficient when the engine 10 is started. When these conditions are satisfied, it can be detected that the reason for the shortage of the intake air amount is that the power supply of the battery is stopped and the learning value of the intake air amount is initialized.
[0030]
Next, in step 110, the flow rate learning value (initial intake air amount) is raised according to the number of corrections. A map of the raising amount corresponding to the number of corrections is stored in the ROM, and the ECU 40 calculates the raising amount of the learning value based on the number of corrections by referring to the raising amount map, and the learning value is calculated by the calculated value. Raise.
For example, in this raising amount map, the raising amount is initially set to a large value, and the raising amount is set to a smaller value as the number of corrections increases. The raised flow learning value is guarded by an upper limit value. In step 110, the number of corrections is incremented by one. The number of corrections is also guarded by the upper limit value. Then, this process ends.
[0031]
Therefore, in the learning of the flow rate learning value that is performed every time the engine is started, when the flow rate learning value reaches the upper limit guard value, the subsequent increase of the flow rate learning value is not performed. Further, when the number of corrections reaches the upper limit guard value, the flow rate learned value is not increased thereafter even if the flow rate learned value does not reach the upper limit guard value.
[0032]
As described above in detail, according to the intake control device of this embodiment, the following excellent effects can be obtained.
In the present embodiment, the learning value of the initial intake air amount is raised when the engine 10 is subsequently started based on the detection of the stall of the engine 10 caused by deposit accumulation. For this reason, the amount of intake air into the combustion chamber 15 of the engine 10 is increased, and stalling of the internal combustion engine can be avoided. Further, when learning of the throttle valve 24 is also performed during ISC control, the learning value of the intake air amount is increased in this way even if the learned value is initialized. Thus, it is possible to ensure the start of the engine 10. In this case, the start of the engine 10 is ensured in this way, so that the learning is newly resumed. Thereafter, the engine operation based on the new learning value is secured.
[0033]
-In this embodiment, whenever the stall of the engine 10 is detected, the learning value of the intake air amount at the start of the engine 10 is increased. For this reason, after the engine 10 is stalled, it is possible to try to start the throttle valve 24 while gradually increasing the opening of the throttle valve 24 based on the learning value. It becomes possible.
[0034]
(Second Embodiment)
Next, a second embodiment of the intake air control apparatus for an internal combustion engine according to the present invention will be described based on FIG. 3 with a focus on differences from the first embodiment. In the present embodiment, the configuration of the engine 10 and its surroundings is the same as that of FIG.
[0035]
In the second embodiment, when the engine 10 is started, it is detected whether or not the deposit attached to the intake passage 19 has been removed, and the intake air with respect to the idle opening of the throttle valve 24 is determined according to the reason for the change in the flow rate. I try to learn changes in quantity.
[0036]
Next, the learning control routine executed by the ECU 40 will be described in detail according to the flowchart shown in FIG. This routine is executed every time the engine 10 is started.
[0037]
As shown in FIG. 3, when the process proceeds to this routine, it is first determined in step 200 whether or not the engine 10 has been started based on the following plurality of conditions. This condition is (1) the cooling water temperature is a predetermined value or more,
(2) Within a predetermined time after engine startup,
(3) The learning value decrease determination time is a predetermined value or more, that is, a time for determining whether or not the flow rate learning value may be decreased is a predetermined value or more,
(4) Before completion of learning of the intake air amount. When all these conditions are met, it is determined that the engine 10 has been started.
That is, since the intake air amount is exceeded when the engine 10 is started, it is determined that the idle rotation speed of the engine 10 exceeds the predetermined rotation speed. When these conditions are satisfied, it can be detected that the reason for the excess of the intake air amount is that the deposit attached to the intake passage 19 has been removed.
[0038]
Next, in step 210, the flow rate learning value (initial intake air amount) is decreased by a predetermined amount corresponding to the engine rotation speed for each of the N range and D range of the transmission shift position. A map in which a decrease value corresponding to the engine speed is set for each of the N range and D range is stored in the ROM, and the ECU 40 calculates the correction amount of the learning value by referring to the map based on the engine speed. The learning value is decreased by the calculated value. Further, the learning value decrease determination time is cleared and the present process is terminated.
[0039]
As described above in detail, according to the intake control device of this embodiment, the following excellent effects can be obtained.
In this embodiment, the amount of intake air increases even at the same idle opening by cleaning and removing deposits adhering to the intake passage 19 or replacing the intake passage 19 itself with another new part. When the engine 10 is started, the idle rotation speed increases from a predetermined value. Based on this detection, the learning value of the intake air amount stored in the RAM or the like is reduced when the engine 10 is subsequently started. For this reason, the amount of intake air into the combustion chamber 15 of the engine 10 is reduced, and the blow-up of the internal combustion engine can be avoided. In addition, when the learning value of the throttle valve 24 is also learned during normal ISC control, the idle rotation speed of the engine 10 can be maintained at a predetermined rotation speed by reducing the learning value of the intake air amount. become able to. In this case, the start of the engine 10 is ensured in this way, so that the learning is newly resumed. Thereafter, the engine operation based on the new learning value is secured.
[0040]
In addition, the said embodiment can also be suitably changed as follows, for example.
In the first embodiment, every time a stall of the engine 10 is detected, the flow rate learning value is increased by an amount set according to the number of corrections. However, every time a stall of the engine 10 is detected, the flow rate The learning value may be increased by a certain amount.
[0041]
In this case, the predetermined amount to be increased may be corrected or changed according to the exhaust pressure, the water temperature, etc. at that time.
In the first embodiment, the upper limit guard value for the flow rate learning value is set in step 110 and the upper limit guard value for the number of corrections is set. However, either one of these upper limit guard values may be omitted. Good.
[0042]
In the second embodiment, the decrease amount of the flow rate learning value is set for each of the N range and D range of the shift position in step 210. However, the fixed amount may be decreased regardless of the shift position. .
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an internal combustion engine to which an intake control device according to a first embodiment of the present invention is applied.
FIG. 2 is a flowchart showing a processing procedure of a “flow rate learning control routine” according to the first embodiment.
FIG. 3 is a flowchart showing a processing procedure of a “flow rate learning control routine” according to a second embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 11 ... Cylinder bore, 12 ... Cylinder block, 13 ... Cylinder head, 14 ... Piston, 15 ... Combustion chamber, 16 ... Spark plug, 17 ... Intake port, 18 ... Exhaust port, 19 ... Intake passage, 20 ... Exhaust passage, 21 ... intake valve, 22 ... exhaust valve, 23 ... injector, 24 ... electronically controlled throttle valve, 25 ... motor, 25a ... throttle sensor, 26 ... distributor, 27 ... igniter, 28 rotational speed sensor ..., 29 vehicle speed sensor ..., 30 ... Accelerator pedal, 31 ... Accelerator switch, 31a ... Accelerator sensor, 32 ... Water temperature sensor, 40 ... Electronic control unit (ECU).

Claims (5)

Control means for performing feedback control so that the idle rotational speed of the internal combustion engine becomes a predetermined rotational speed by adjusting an idle opening degree of a throttle valve provided in an intake passage of the internal combustion engine based on a learning value of an intake air amount An intake control device for an internal combustion engine comprising:
First learning means for learning a change in an intake air amount with respect to an idle opening of the throttle valve;
Flow rate change reason detecting means for detecting whether or not the learning value by the first learning means has been initialized ;
An intake control device for an internal combustion engine, comprising: a second learning unit that learns a change in an intake air amount with respect to an idle opening of the throttle valve according to initialization of the learned value . The intake control apparatus for an internal combustion engine according to claim 1,
The intake rate of the internal combustion engine, wherein the flow rate change reason detecting means detects that the learning value of the first learning means is initialized based on interruption of power supply from the battery. Control device. The intake control apparatus for an internal combustion engine according to claim 2,
The intake control device for an internal combustion engine, wherein the second learning means raises a predetermined amount with respect to the learning initial value of the intake air amount. Control means for performing feedback control so that the idle rotational speed of the internal combustion engine becomes a predetermined rotational speed by adjusting an idle opening degree of a throttle valve provided in an intake passage of the internal combustion engine based on a learning value of an intake air amount An intake control device for an internal combustion engine comprising:
First learning means for learning a change in an intake air amount with respect to an idle opening of the throttle valve;
A flow rate change reason detecting means for detecting that the deposit adhering to the vicinity of the throttle valve is removed in the intake passage ;
Second learning means for learning a change in an intake air amount with respect to an idle opening of the throttle valve in response to detection of removal of the deposit;
Intake air control system for an internal combustion engine, characterized in that it comprises a. The intake control device for an internal combustion engine according to claim 4,
The intake control device for an internal combustion engine, wherein the second learning means decreases a predetermined amount from a learned value of the intake air amount learned by the first learning means.

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