JPH1130176A - Ignition timing control device for internal combustion engine - Google Patents

Abstract

(57) Abstract: The present invention relates to an ignition timing control device that changes an ignition timing according to a warm-up state of an internal combustion engine, and an object thereof is to realize excellent drivability in a warm-up process of the internal combustion engine. I do. SOLUTION: A learning value KDPC for eliminating an influence of a deposit attached to an internal combustion engine is learned. An advance reference value ACLD is calculated based on the cooling water temperature THW of the internal combustion engine (step 144). A correction advance value ACLD1 is calculated based on the learning value KDPC (step 148). The advance reference value ACLD and the corrected advance value A are added to the base advance value ABSE.
The ignition timing advance amount AOP is calculated by adding CLD1 to the ignition timing (step 150).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an ignition timing control device for an internal combustion engine, and more particularly to an ignition timing control device for an internal combustion engine that changes an ignition timing in accordance with a warm-up state of the internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Unexamined Patent Publication No.
As disclosed in Japanese Unexamined Patent Application Publication No. H11-264, there is known a device for advancing ignition timing at the time of starting an internal combustion engine. When starting the internal combustion engine,
The temperature of the combustion chamber is lower than after the warm-up. In this case, the combustion speed of the fuel becomes slower than after the warm-up. Therefore, in order to obtain good drivability at the start of the internal combustion engine, it is appropriate to advance the ignition timing as compared to after the warm-up, that is, to change the ignition timing to the advanced side as compared to after the warm-up. It is.

During the ignition timing advance control, the ignition may be performed during the compression process, that is, in the process in which the piston is displaced toward the top dead center. On this occasion,
If the ignition timing is excessively advanced, unburned fuel may adhere to the spark plug after ignition, and the ignitability of the spark plug may deteriorate. Hereinafter, this phenomenon is called a smoldering phenomenon. Accordingly, in the above-described conventional apparatus, when the ignition timing is advanced when the internal combustion engine is started, it is necessary to set the advance amount to a value that does not cause the smoldering phenomenon.

[0004] In the field of internal combustion engines, conventionally, for example, as disclosed in JP-A-5-33697,
In order to eliminate the effect of the deposit attached to the internal combustion engine, a deposit learning value KDPC is learned, and the learning value KDPC is learned.
A device that corrects a fuel injection amount by using a device is known. In some cases, carbon or the like is deposited in a combustion chamber or the like of an internal combustion engine and deposits are attached thereto. When the deposit is attached to the internal combustion engine, a part of the fuel supplied to the internal combustion engine is absorbed by the deposit. For this reason, when deposits adhere to the internal combustion engine, a time lag occurs between the time when the amount of fuel injected into the internal combustion engine changes and the time when the amount of fuel consumed for combustion changes. Accordingly, if the fuel injection amount is controlled in the presence of the deposit in the same manner as when the deposit does not exist, for example, when acceleration of the internal combustion engine is required, the output torque may not rise quickly.

[0005] The above-mentioned conventional apparatus calculates a learning value KDPC based on the air-fuel ratio at the time of acceleration and calculates a fuel injection amount using the learning value KDPC in order to eliminate the influence of the above-mentioned deposit. The learning value KDPC is obtained when the air-fuel ratio becomes fuel-lean during acceleration of the internal combustion engine, that is,
If it can be determined that the increased amount of fuel has been sucked into the deposit, it is updated to a larger value. Also, the learning value K
The DPC is updated to a smaller value when the air-fuel ratio becomes fuel-rich during acceleration of the internal combustion engine, that is, when it can be determined that the increased amount of fuel is not absorbed in the deposit.

According to the above-described processing, even if the amount of the deposit adhering to the internal combustion engine changes with time, and the degree of the effect of the deposit on the air-fuel ratio changes with the change,
The effect of deposit can always be eliminated. Therefore, according to the above-described conventional apparatus, good drivability can always be ensured without being affected by the amount of deposit.

In the internal combustion engine, the ignition timing advance control and the fuel injection amount control using the learning value KDPC can be executed together. When these controls are executed in combination, excellent driveability can be obtained in the process of warming up the internal combustion engine, and good drivability can be maintained for a long period of time regardless of the aging of the internal combustion engine.

[0008]

However, in the above-described conventional apparatus, the update of the learning value KDPC is performed after the internal combustion engine has been warmed up. After the warm-up, the fuel exhibits better vaporization properties than immediately after the start. The effect of the deposit on the air-fuel ratio decreases as the fuel exhibits better vaporization. Therefore, in the above-described conventional device, the learning value KDPC
Corresponds to the situation after the effect of the deposit has been reduced.

In the above conventional apparatus, the learning value KDPC
Is also executed until the warm-up of the internal combustion engine ends. Until the warm-up of the internal combustion engine is completed, the fuel vaporization is poorer than after the warm-up is completed. For this reason, the deposit adhering to the internal combustion engine has a greater effect on the air-fuel ratio before the completion of the warm-up than in the case after the completion of the warm-up. In this case, the correction using the learning value KDPC cannot eliminate all the effects of the deposit. Therefore, according to the above-described control method, when deposits adhere to the internal combustion engine, the air-fuel ratio tends to be fuel lean until the internal combustion engine is completely warmed up.

As described above, when performing the ignition timing advance control in the internal combustion engine, it is necessary to set the ignition timing advance amount to a value that does not cause the smoldering phenomenon. The smoldering phenomenon is more likely to occur as the air-fuel ratio is richer in fuel. Therefore, in an internal combustion engine in which the above method is used as a control method for eliminating the effect of the deposit, the smoldering phenomenon is less likely to occur when the deposit is attached than when the deposit is not attached. For this reason, when performing the ignition timing advance control in such an internal combustion engine, it is possible to use a larger advance amount as the deposit amount is larger.

In the conventional internal combustion engine, when the control for eliminating the effect of the deposit using the learning value KDPC and the advance control for the ignition timing are executed together, the advance amount of the ignition timing is determined by the amount of deposit on the deposit. The control for changing according to the state has not been executed. In this regard, the conventional ignition timing control method still leaves room for improvement. The present invention has been made in view of the above points, and an internal combustion engine that realizes better drivability in a warm-up process of the internal combustion engine by changing an advance amount of ignition timing according to a deposit state of a deposit It is an object of the present invention to provide an ignition timing control device.

[0012]

The above object is achieved by the present invention.
In an ignition timing control device for an internal combustion engine that changes an ignition timing in accordance with a warm-up state of the internal combustion engine, an advance reference value calculation unit that calculates an advance reference value based on the temperature of the internal combustion engine, A deposit learning means for learning the effect of the deposit attached to the internal combustion engine on the air-fuel ratio; a correction advance value calculation means for calculating a correction advance value based on a learning result of the deposit learning means; This is achieved by an ignition timing control device for an internal combustion engine including: an advance amount calculating means for calculating an advance amount of an ignition timing based on the value and the corrected advance value.

In the present invention, the advance amount of the ignition timing is calculated based on the advance reference value and the corrected advance value. The advance angle reference value is calculated based on the temperature of the internal combustion engine, that is, based on the warm-up state of the internal combustion engine. For this reason, the advance amount is changed to an appropriate value as the internal combustion engine warms up. The corrected advance value is calculated based on the learning result of the deposit learning means. For this reason, the advance amount is updated to an appropriate value according to the attached state of the deposit.

[0014]

FIG. 1 is a system configuration diagram of an internal combustion engine 10 according to one embodiment of the present invention. Internal combustion engine 10
Is an electronic control unit 12 (hereinafter, referred to as ECU 12)
Is controlled by The internal combustion engine 10 includes a cylinder block 14. A water jacket 16 is formed in the wall of the cylinder block 14. The piston 18 and the connecting rod 20 are housed inside the cylinder block 14. Also, cylinder block 1
A water temperature sensor 22 for detecting the temperature of the cooling water flowing inside the water jacket 16 is provided on the wall surface of the water jacket 4. The output signal of the water temperature sensor 24 is supplied to the ECU 12. The ECU 12 detects the coolant temperature THW based on the output signal of the coolant temperature sensor 24.

A cylinder head 24 is fixed above the cylinder block 14. A combustion chamber 26 is formed between the cylinder head 24 and the piston 18. An intake port 28 and an exhaust port 30 communicating with the combustion chamber 26 are formed in the cylinder head 24.
The cylinder head 24 has an intake valve 32 for opening and closing the intake port 28 and an exhaust valve 3 for opening and closing the exhaust port 30.
4, and a spark plug 36 whose tip is exposed to the combustion chamber 26 is incorporated. The spark plug 36 generates a spark inside the combustion chamber 26 when a high-pressure ignition signal is supplied at a predetermined timing, as described later.

The intake port 28 has an intake manifold 3
8 are in communication. An injector 40 is provided in the intake manifold 38. The injector 40 is connected to a fuel pump via a fuel pipe (not shown), and is also electrically connected to the ECU 12. The injector 40 injects fuel to the intake port 28 only during a period during which a drive signal is supplied from the ECU 12, that is, during a fuel injection period TAU.

The intake manifold 38 is provided with the surge tank 4
It communicates with 2. Further, the surge tank 42 communicates with an intake pipe 44. Inside the intake pipe 44, a throttle valve 46 that operates in conjunction with an accelerator pedal is provided. A throttle sensor 48 that outputs a signal corresponding to the opening of the throttle valve 46 is provided near the throttle valve 46. Throttle sensor 48
Are supplied to the ECU 12. ECU12
Detects the opening of the throttle valve based on the output signal of the throttle sensor 48.

The internal combustion engine 10 has a bypass passage 50 in parallel with the intake pipe 44. An idle speed control valve 52 (hereinafter, ISC)
V52). ISCV52 is E
It is electrically connected to the CU 12. When the internal combustion engine 10 is in idle operation,
When the throttle valve 46 is fully closed,
In order to allow an appropriate amount of air to flow through the bypass passage 50,
The opening of the CV 52 is controlled.

An air flow meter 54 communicates with the intake pipe 44. Air that has passed through an air filter (not shown) flows into the air flow meter 54. Air flow meter 5
0 generates an output signal corresponding to the mass and weight of the air flowing inside (hereinafter simply referred to as the intake air amount G). The output signal of the air flow meter 54 is supplied to the ECU 12. The ECU 12 detects the intake air amount G of the internal combustion engine 10 based on the output signal of the air flow meter 54.

An exhaust manifold 56 communicates with the exhaust port 30 of the internal combustion engine 10. Exhaust manifold 5
6 is provided with an O ₂ sensor 58. O ₂ sensor 5
8 outputs a signal corresponding to the oxygen concentration in the exhaust gas flowing through the exhaust manifold 56. The output signal of the O ₂ sensor 58 is supplied to the ECU 12. The ECU 12
Based on the output signal of the O ₂ sensor 58, the air-fuel ratio of the air-fuel mixture supplied to the internal combustion engine 10 is detected.

The internal combustion engine 10 includes an igniter 60 and an ignition coil 62. Igniter 60
Are electrically connected to the ECU 12. ECU12
Supplies an ignition signal to the igniter 60 at a timing at which ignition is performed in any one of the cylinders of the internal combustion engine 10. The igniter 60 supplies a primary current to the ignition coil 62 in synchronization with the ignition signal. Ignition coil 62
When the primary current is supplied to the ignition coil 62
, A high-pressure ignition signal is generated.

On the secondary side of the ignition coil 62,
Distributor 64 is connected. The distributor 64 has the same number of output terminals as the number of cylinders of the internal combustion engine. The terminals are connected to the internal combustion engine 1 respectively.
0 is connected to a spark plug disposed in each cylinder.
The distributor 64 includes the ignition coil 62
Is distributed to ignition plugs of appropriate cylinders according to the crank angle of the internal combustion engine 10.

The distributor 64 includes an internal combustion engine 1
A cylinder discrimination sensor 66 that generates a pulse signal each time the crank angle of 0 reaches the reference angle, and a rotation angle sensor that generates a pulse signal each time the crank angle of the internal combustion engine rotates by a predetermined rotation angle (for example, 30 ° CA) 68 are built in. Output signal of cylinder discrimination sensor 66 and rotation angle sensor 6
8 are both supplied to the ECU 12. E
The CU 12 calculates the rotation angle of the internal combustion engine 10 and the engine speed NE of the internal combustion engine 10 based on the output signals of these sensors.

In the system according to the present embodiment, after the internal combustion engine 10 is started, until the warm-up is completed, the ignition timing is corrected to the advanced side as compared with after the warm-up is completed, that is, the control is performed. The ignition timing advance control is performed. The temperature of the combustion chamber 26 is lower until the warm-up of the internal combustion engine 10 is completed, compared to the temperature after the warm-up is completed. When the temperature of the combustion chamber 26 is low, the combustion speed of the fuel becomes low. In this case, it is appropriate to advance the ignition timing in order to obtain good drivability. When the temperature of the combustion chamber 26 is low, knocking in the internal combustion engine 10 is less likely to occur. For this reason, in the warming-up process of the internal combustion engine, it is possible to use a larger advance amount than after the warming-up without knocking.

Therefore, as described above, if the ignition timing advance control is performed after the start of the internal combustion engine 10 until the warm-up of the internal combustion engine 10 is completed, the process of warming up the internal combustion engine 10 is performed. Good drivability can be realized without causing knocking. by the way,
When the ignition timing advance control is performed in the internal combustion engine 10, if the excessive advance amount AOP is used, the combustion chamber 2
A situation occurs in which ignition occurs before the mixture in 6 is sufficiently compressed. If the ignition is performed before the mixture is sufficiently compressed, the mixture will burn into the combustion chamber 26 relatively slowly. At this time, the internal pressure of the combustion chamber 26 increases as the air-fuel mixture burns. When the above phenomenon occurs inside the combustion chamber 26, unburned fuel enters between the insulator portion of the ignition plug 36 and the cylinder head 24, and the ignitability of the ignition plug 36 deteriorates due to the influence of the fuel. That is, a smoldering phenomenon may occur. For this reason, when performing the ignition timing advance control in the internal combustion engine 10, it is necessary to regulate the ignition timing advance amount AOP to a value that does not cause the smoldering phenomenon.

In the system of the present embodiment, in order to eliminate the effect of deposits adhering to the combustion chamber 26 and the like of the internal combustion engine 10, the fuel injection time T depends on the adhering state of the deposits.
Control for correcting AU is executed. A deposit mainly composed of a deposit such as carbon adheres to the combustion chamber 26 and the like of the internal combustion engine 10. The deposit adsorbs a part of the fuel injected from the injector 40. When the operating state of the internal combustion engine 10 is steady, the amount of fuel adsorbed on the deposit and the amount of fuel desorbing from the deposit are balanced. In this case, the amount of fuel consumed for combustion in the internal combustion engine 10 is equal to the amount of fuel injected from the injector 40.

On the other hand, when the internal combustion engine 10 is accelerating, that is, when the fuel injection amount injected from the injector 40 and the intake air amount G are increased, the amount of fuel adsorbed on the deposit becomes May be large compared to the amount of fuel leaving the deposit. in this case,
The amount of fuel consumed for combustion in the internal combustion engine 10 is smaller than the amount of fuel injected from the injector 40.

Therefore, when the internal combustion engine 10 is required to accelerate, in order to quickly increase the output torque in accordance with the request, the amount of fuel adsorbed on the deposit and the amount of fuel desorbing from the deposit must be reduced. It is necessary to increase and correct the fuel injection amount injected from the injector 40 so as to compensate for the difference. In this embodiment, the ECU
10 learns a learning value KDPC representing the deposit adsorption state, and uses the learning value KDPC to calculate the fuel injection time TA.
The above function is realized by correcting U.

FIG. 2 shows a flowchart of an example of a control routine executed by the ECU 10 to learn the learning value KDPC. The routine shown in FIG. 2 is a periodic interrupt routine that is started every predetermined time. When the routine shown in FIG. 2 is started, first, the process of step 100 is executed. In step 100, it is determined whether the air-fuel ratio feedback control is being performed. In the internal combustion engine 10, the air-fuel ratio feedback control is executed when a predetermined execution condition is satisfied. The air-fuel ratio feedback control is performed based on the output signal of the O ₂ sensor 58 so that the air-fuel ratio of the air-fuel mixture becomes the stoichiometric air-fuel ratio.
This is control for correcting AU. According to the air-fuel ratio feedback control, the air-fuel ratio of the air-fuel mixture can be accurately controlled near the stoichiometric air-fuel ratio.

In this embodiment, the learning value KDPC is updated during execution of the air-fuel ratio feedback control. Therefore, if it is determined in step 100 that the air-fuel ratio feedback control has not been executed, the learning value KDPC is not updated. In this case, after this, the process of step 136 is executed, and then the current routine is terminated. On the other hand, when it is determined that the air-fuel ratio feedback control is being executed, the process of step 102 is executed next.

In step 102, the cooling water temperature THW
Is not less than 80 ° C. and less than 100 ° C. As a result, when it is determined that 80 ° C. ≦ THW <100 is satisfied, it can be determined that the internal combustion engine 10 is appropriately warmed up. In this embodiment, the learning value KDP
The updating of C is executed when the internal combustion engine 10 is properly warmed up. Therefore, step 10
If it is determined in step 2 that 80 ° C. ≦ THW <100 is not established, the learning value KDPC is not updated. In this case, after this, the process of step 136 is executed, and then the current routine is terminated. On the other hand, if it is determined that the above condition is satisfied, the process of step 104 is executed next.

In step 104, the post-start increase FAS
It is determined whether both E and the warm-up increase FWL are both “0”. Immediately after the start of the internal combustion engine 10, a post-start increase correction for executing an increase correction of the fuel injection amount is executed. The post-start increase FASE is a value that is added to the basic fuel injection amount during the above-described post-start increase correction. Further, in the internal combustion engine 10, a warm-up increase correction for increasing the fuel injection amount during the warm-up process is executed.
The warm-up increase FWL is a value added to the basic fuel injection amount during the above-described warm-up increase correction.

In the present embodiment, the update of the learning value KDPC is executed under the condition that the fuel is not increased. Therefore, in the above step 104, FASE
= 0 and FWL = 0 is not established,
The learning value KDPC is not updated. In this case,
After the processing of step 136 is performed, the current routine ends. On the other hand, when it is determined that the above condition is satisfied, the process of step 106 is executed next.

In step 106, it is determined whether or not the engine speed NE is lower than a predetermined speed of 3200 rpm. In the present embodiment, the update of the learning value KDPC is not executed during the high-speed operation of the internal combustion engine 10. Therefore, when it is determined that NE <3200 is not established, the process of step 136 is thereafter executed, and then the current routine is terminated. On the other hand, if it is determined that the above condition is satisfied, the process of step 108 is performed next.

In step 108, the intake pipe pressure PMTA
It is determined whether or not the change rate DLPMTA is equal to or greater than a predetermined value A. As a result, when DLPMTA ≧ A is satisfied, it can be determined that the internal combustion engine 10 is in the predetermined acceleration state. In the present embodiment, the learning value KDPC is the internal combustion engine 1
At 0, the update is performed while the predetermined acceleration state is maintained. Therefore, if it is determined that DLPMTA ≧ A is not satisfied, the process of step 136 is executed thereafter, and the current routine ends. On the other hand, if it is determined that the above condition is satisfied, then step 1
Ten processes are executed.

At step 110, it is determined whether or not "1" is set in the flag XDPC. The flag XDPC is a flag that is set to “1” when a condition for starting the update of the learning value KDPC is satisfied. If it is determined in step 110 that XDPC = 1 does not hold, the process of step 112 is executed next. on the other hand,
If it is determined that XDPC = 1 is established, step 112 is jumped, and the process of step 114 is executed.

In step 112, the intake pipe pressure PMTA
It is determined whether or not the change rate DLPMTA is equal to or greater than a predetermined value B (> A). In the present embodiment, the internal combustion engine 10
Is in an acceleration state in which DLPMTA ≧ B is satisfied, it is determined that the update start condition for the learning value KDPC is satisfied. Therefore, if it is determined that DLPMTA ≧ B is not satisfied, the routine of step 136 is performed thereafter, and then the current routine ends. On the other hand, when it is determined that the above condition is satisfied, the process of step 114 is executed next.

In step 114, "1" is set to the flag XDPC. When the processing of step 114 is performed, it is determined that XDPC = 1 is established when step 110 is performed in the next and subsequent processing cycles. In step 116, the first counter CDP
A process for incrementing C1 is performed. The first counter CDPC1 is a counter for counting the number of times that the processing after step 116 has been executed after the start of the update processing of the learning value KDPC. The first counter C
DPC1 has been cleared to "0" at the time when the process of updating the learning value KDPC is started by the process of step 136 described later.

In step 118, the first counter CDP
It is determined whether C1 is greater than 2 or not. As a result, when it is determined that CDPC> 2 is not satisfied, it can be determined that the effect of the acceleration has not yet been reflected on the oxygen concentration in the exhaust gas after the acceleration of the internal combustion engine 10 has been started. In this case, the current routine is terminated without any further processing. On the other hand, if it is determined that CDPC1> 2 is satisfied, the process of step 120 is performed next.

In step 120, it is determined whether or not the air-fuel mixture is rich based on the output signal of the O ₂ sensor 58. As a result, when it is determined that the air-fuel mixture is fuel-rich, the amount of fuel consumed for combustion is appropriately increasing during acceleration of the internal combustion engine 10, that is, the lean air-fuel ratio caused by the deposit is increased. It can be determined that no conversion has occurred. In this case, the process of step 122 is performed next.

In step 122, the second counter CDP
A process of decrementing C2 is executed. The second counter CDPC2 is a counter for counting the difference between the number of times that the air-fuel ratio is determined to be fuel-rich and the number of times that the air-fuel ratio is determined not to be fuel-rich in the process of step 120. According to the above processing, the second counter C
The count value of DPC2 is decremented each time it is determined that the air-fuel ratio due to the deposit has not been made lean.

In this routine, if it is determined in step 120 that the air-fuel mixture is not fuel-rich, the internal combustion engine 1
With the acceleration of 0, it can be determined that the air-fuel ratio becomes lean due to the deposit. In this case, the process of step 124 is executed next. In step 124, a process of incrementing the second counter CDPC2 is executed. According to the above processing, the second counter CDPC2
Is incremented each time it is determined that the air-fuel ratio due to the deposit is lean.

In step 126, the first counter CDP
It is determined whether the count value of C1 has reached "10". As a result, if it is determined that CDPC1 = 10 has not been established, the current routine is terminated without any further processing. On the other hand, CDPC1 = 10
Is satisfied, the process of step 128 is executed next. According to the above processing, step 12
Processes 8 and after are executed every time the determination of step 120 is repeated eight times after the process of updating the learning value KDPC is started.

In step 128, the second counter CDP
It is determined whether or not the count value of C2 is "4" or more.
As a result, when it is determined that CDPC2 ≧ 4 is satisfied, it can be determined that the leaning of the air-fuel ratio due to the deposit frequently occurs. In this case, step 13
0 is executed. On the other hand, if it is determined that CDPC2 ≧ 4 is not satisfied, the process of step 132 is executed next.

In step 130, the learning value KDPC is
The value is updated to a value larger by the predetermined value α. According to the above processing, the learning value KDPC can be updated to a large value when leaning of the air-fuel ratio due to the deposit is frequently observed. In step 132, the second counter CD
It is determined whether the count value of PC2 is equal to or less than "-4". As a result, when it is determined that CDPC2 ≦ −4 is satisfied, it can be determined that the leaning of the air-fuel ratio due to the deposit hardly occurs. In this case, the process of step 134 is executed next. On the other hand, if it is determined that CDPC2 ≦ −4 is not established, the process of step 136 is performed next.

In step 134, the learning value KDPC is
The value is updated to a value smaller by the predetermined value α. According to the above processing, the learning value KDPC can be updated to a small value when the leaning of the air-fuel ratio due to the deposit is hardly recognized. In step 136, the first counter CD
A process of clearing PC1 and the second counter CDPC2 to “0” and resetting the flag XDPC to “0” is executed. When the process of step 136 ends, the current routine ends.

As described above, in the present embodiment, when the leaning of the fuel due to the deposit frequently occurs,
That is, when it is necessary to increase the fuel injection amount in order to eliminate the influence of the deposit, the learning value KDPC can be updated to a large value. In addition, when the leaning of the fuel due to the deposit hardly occurs,
When it is not necessary to increase the fuel injection amount for eliminating the effect of the deposit, the learning value KDPC can be updated to a small value.

In this embodiment, when acceleration of the internal combustion engine 10 is required, the ECU 10 adds a time proportional to the learning value KDPC to a basic fuel injection time to obtain a fuel injection time TAU. Therefore, the internal combustion engine 10 can increase the output torque with excellent responsiveness when acceleration is required regardless of the presence or absence of a deposit.

Incidentally, in the present embodiment, the learning value KD
The PC is updated when the internal combustion engine 10 is properly warmed up. Therefore, the value of the learning value KDPC corresponds to the vaporization property of the fuel when the internal combustion engine 10 is properly warmed up. The higher the ambient temperature of a fuel, the better the vaporization. Therefore, the fuel does not exhibit excellent vaporization properties before the warming-up of the internal combustion engine 10 ends, as much as after the warming-up ends.

The leaning of the air-fuel ratio caused by the deposit becomes more noticeable as the fuel vaporization property becomes worse. Therefore, when the deposit is deposited on the internal combustion engine 10, the air-fuel ratio is more likely to be lean before the warm-up of the internal combustion engine 10 is completed, compared to after the warm-up is completed. The learning value KDPC used in the system of the present embodiment is a value for avoiding leaning of the air-fuel ratio due to the deposit when the internal combustion engine 10 has been warmed up as described above. .
Therefore, depending on the learning value KDPC, it is not possible to cancel the leaning that appears in the air-fuel ratio due to the deposit before the warm-up ends. For this reason, the internal combustion engine 10
When the fuel increase correction using the learning value KDPC is performed, the air-fuel ratio is likely to be biased toward the fuel lean side in the warm-up process of the internal combustion engine 10 even if the fuel amount is corrected using the learning value KDPC.

As described above, in the system of the present embodiment, the ignition timing is advanced in the process of warming up the internal combustion engine 10. At this time, in order to obtain good drivability, it is appropriate to secure the ignition timing advance amount AOP as large as possible within a range that does not cause inconvenience such as a smoldering phenomenon. The smoldering phenomenon of the ignition plug 36 is more likely to occur as the air-fuel mixture supplied to the combustion chamber 26 is richer in fuel. Therefore, when performing the advance control of the ignition timing, the more the air-fuel mixture supplied to the combustion chamber 26 is fuel-lean, the larger the advance amount AOP can be used.

As described above, when deposits adhere to the internal combustion engine 10, the air-fuel ratio tends to be biased toward the fuel lean side during the warm-up process. In addition, the deviation of the air-fuel ratio toward the fuel lean side increases as the amount of deposit attached increases.
Accordingly, in order to make the advance amount AOP as large as possible during the warm-up process of the internal combustion engine 10, it is appropriate to appropriately set the advance amount AOP based on the amount of deposit.

In the system of this embodiment, the learning value KD
PC can be grasped as a characteristic value of the amount of deposit attached. Therefore, in the present embodiment, the learning value KDPC
By setting the advance amount AOP based on the following formula, the advance amount AO is as large as possible within a range that does not cause the smoldering phenomenon.
P can be determined. The internal combustion engine 10 of the present embodiment includes:
The feature is that the advance amount AOP is set by the above method. Hereinafter, with reference to FIG. 3 and FIG.
Will be described.

FIG. 3 shows the ECU 1 for realizing the above functions.
0 shows a flowchart of an example of a control routine executed by the control routine 0. The routine shown in FIG. 3 is a periodic interruption routine that is started every predetermined time. In the routine shown in FIG. 3, first, the process of step 140 is executed. In step 140, the cooling water temperature THW of the internal combustion engine 10 is read.

In step 142, the cooling water temperature THW is set to 8
It is determined whether the temperature is 0 ° C. or higher. As a result, THW
If it is determined that ≧ 80 ° C. holds, the internal combustion engine 10
It can be determined that the warm-up has already been completed. In this case, this routine ends without executing the ignition timing advance control. On the other hand, if it is determined that THW ≧ 80 ° C. is not satisfied, the process of step 144 is executed next.

In step 144, the advance reference value ACLD
Is calculated. The advance angle reference value ACLD is an advance angle value set according to the warm-up state of the internal combustion engine 10. FIG. 4 shows an example of a map representing the relationship between the cooling water temperature THW and the advance angle reference value ACLD. In the above step 144, the ECU
Reference numeral 10 denotes a cooling water temperature THW with reference to the map shown in FIG.
, The advance reference value ACLD is calculated. As shown in FIG. 4, the advance reference value ACLD is set to a smaller value as the coolant temperature THW becomes higher, that is, as the warm-up of the internal combustion engine 10 progresses.

At step 146, the learning value KDPC calculated by the routine shown in FIG. 2 is read. In step 148, a corrected advance angle value ACLD1 is calculated.
In this step 148, the corrected advance angle value ACLD1 is calculated by multiplying the learning value KDPC by the proportional constant β. According to the above-described processing, the larger the deposit amount, the larger the correction advance value ACLD1 can be.

In step 150, the advance angle amount AOP is calculated. The advance amount AOP is calculated by adding the advance reference value ACLD and the corrected advance value ACLD1 to the base advance value ABSE (constant). When the process of step 150 ends, the current routine ends. According to the above processing, the advance angle amount AOP can be made smaller as the warm-up of the internal combustion engine 10 progresses, and can be made larger as the amount of deposit attached increases. Therefore, according to the internal combustion engine 10, during the warm-up process, the ignition timing can be controlled as far as possible to the advanced side as long as the smoldering phenomenon does not occur. Therefore, according to the internal combustion engine 10, excellent drivability can be obtained during the warm-up process.

In the above embodiment, the ECU 10
By executing the processing of step 144, the “advance angle reference value calculating means” according to claim 1 executes the processing of steps 100 to 136 to execute “deposit learning means” according to claim 1. "Performs the processing of steps 146 and 148, whereby the" correction advance value calculating means "according to claim 1 executes the processing of step 15
By executing the processing of 0, the “advance angle amount calculating means” according to claim 1 is realized.

[0060]

As described above, according to the present invention, the advance amount of the ignition timing can be set to an appropriate value according to the warm-up state of the internal combustion engine and the adhesion state of the deposit. For this reason, according to the present invention, good drivability can be realized during the warm-up process of the internal combustion engine.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of an internal combustion engine according to one embodiment of the present invention.

FIG. 2 is a flowchart of an example of a control routine executed to calculate a learning value KDPC in the internal combustion engine shown in FIG.

FIG. 3 is a flowchart of an example of a control routine executed to calculate an advance amount AOP in the internal combustion engine shown in FIG. 1;

4 is an advance reference value ACL in the control routine shown in FIG. 3;
It is an example of a map referred to when calculating D.

[Explanation of symbols]

 Reference Signs List 10 internal combustion engine 12 electronic control unit (ECU) 26 combustion chamber 36 spark plug KDPC learning value ACLD advancement reference value ACLD1 corrected advancement value ABSE base advancement value AOP advancement amount

Claims (1)

[Claims] An ignition timing control device for an internal combustion engine that changes an ignition timing in accordance with a warm-up state of the internal combustion engine, wherein an advanced angle reference value calculating means for calculating an advanced angle reference value based on a temperature of the internal combustion engine; Deposit learning means for learning the effect of the deposit attached to the internal combustion engine on the air-fuel ratio; correction advance value calculation means for calculating a correction advance value based on the learning result of the deposit learning means; An ignition timing control device for an internal combustion engine, comprising: an advance amount calculating means for calculating an advance amount of an ignition timing based on the value and the corrected advance value.