JPH0842434A - Ignition timing controller of internal combustion engine - Google Patents

Abstract

PURPOSE:To secure idling stability in a range where ignition does not turn to a state of timing advance at a time when engine load grows larger in time of idle running, and to prevent any knocking from occurring as well as to enable these operations to cope with any change in types of used fuel. CONSTITUTION:An electronic control unit 51 controls an igniter 21 on the basis of target ignition timing, thereby operating a spark plug 8. Further this electronic control unit 51 judges fuel octane value on the basis of the detected result of a knock sensor 38. Likewise, this ECU 51 calculates a first basic ignition timing for usual driving on the basis of engine speed and load from the detected results of both sensors 32 and 36 in time of idle running, thereby calculating a second basic ignition timing for idle running on the basis of the engine sped. In addition, this ECU 51 sets the first basic ignition timing as an upper limit timing at timing advance side in time of idle running, setting the target ignition timing on the basis of both first and second basic ignition timings. At this time, the ECU 51 favorably changes the first basic ignition timing on the basis of the judged result of the octane value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for controlling the ignition timing of an internal combustion engine, and more particularly to an ignition timing control device for controlling the ignition timing during idle operation of the engine.

[0002]

2. Description of the Related Art It has been conventionally known that the ignition timing of an internal combustion engine has a great influence on the exhaust gas, fuel consumption, drivability, etc. of the engine. Therefore, the ignition timing is controlled to be an optimal timing according to the operating state of the engine. Therefore, in a basic ignition timing control device that performs this type of control, a computer calculates an optimal ignition timing according to the operating state of the engine, and operates the spark plug based on the calculated timing. In this type of control device, the computer calculates and determines a prestored optimum ignition timing based on the engine speed and load during normal operation other than idle operation.

On the other hand, in this type of control device, in order to ensure idle stability during idle operation when the load on the engine is small, the computer uses a fixed ignition timing that is uniformly set in advance, or The ignition timing is calculated according to the rotation speed of the.

However, when the internal combustion engine is mounted on an automobile, the auxiliary equipment such as the air conditioner and the power steering operates during the idle operation,
The load on the engine increases. In this case, if the computer simply uses the fixed ignition timing or the ignition timing according to the rotational speed for control, the ignition timing obtained by the control is an excessive advance state with respect to the required ignition timing according to the load state. Becomes Therefore, in the internal combustion engine, so-called knocking may occur or idle stability may deteriorate.

Therefore, the present applicant has proposed an ignition timing control device aiming at addressing the above problems.
It was proposed in Japanese Laid-Open Patent Publication No. 3-309774. In the control device of this publication, when the engine is in a high load state due to the operation of the air conditioner or the like during idle operation of the engine, the electronic control unit (ECU) determines this. And EC
U limits the ignition timing calculated based on the engine rotation speed or the fixed ignition timing determined in advance based on the ignition timing calculated based on the engine load and the rotation speed during normal operation. That is, when the ignition timing calculated during idle operation is on the advance side of the ignition timing calculated during normal operation, the ignition timing calculated during normal operation is used as the ignition timing during idle operation. This prevents the ignition timing from advancing more than necessary. As a result of this control, the idle stability of the engine is further improved.

[0006]

However, fuels used in gasoline engines are generally classified into premium gasoline having a high octane number and regular gasoline having a low octane number. Then, due to the difference in the fuel type, the limit timing at which knocking occurs in the gasoline engine differs, so the optimal ignition timing in the engine differs depending on the fuel type. Therefore, in a premium specification engine that is premised on the use of premium gasoline, various settings relating to ignition timing control are performed in order to obtain the optimum ignition timing according to the type of fuel. Similarly, in a regular engine designed to use regular gasoline, various settings relating to ignition timing control are performed in order to obtain an optimal ignition timing according to the type of fuel.

Here, when the control device of the above publication is applied to a gasoline engine and the engine is of a premium specification, the ECU is idled based on the knocking limit time corresponding to the type of fuel. Limit the ignition timing calculated during operation. That is, the ECU sets the ignition timing during idle operation to a timing on the relatively retarded side. Therefore, for example, when a regular user uses regular gasoline for a premium specification engine, the set knocking limit time is relatively retarded for the fuel type. Will end up. for that reason,
Even though the ignition timing during idle operation is restricted so that the ignition timing will not be advanced, the fuel may self-ignite at a relatively early timing, and it may not be possible to prevent knocking.

Further, the susceptibility to knocking in the engine is somewhat different depending on the individual difference of the engine and the change over time. Therefore, in order to prevent the occurrence of knocking, it is also effective to consider factors such as the individual difference of the engine and the change over time in addition to the type of fuel.

The present invention has been made in view of the above-mentioned circumstances, and a first object thereof is to stabilize the idle stability within a range in which the advance angle is not unnecessarily advanced even if the engine load increases during idle operation. It is an object of the present invention to provide an ignition timing control device for an internal combustion engine, which secures the above conditions, prevents knocking from occurring, and enables them to cope with changes in the type of fuel used.

A second object of the present invention is to ensure idle stability and prevent knocking from occurring in a range that does not lead to an undesired advance even if the engine load increases during idle operation. Change the type of fuel used,
An object of the present invention is to provide an ignition timing control device for an internal combustion engine, which is capable of coping with the individual difference of the engine and the change over time.

[0011]

In order to achieve the above first object, in the first aspect of the present invention as set forth in claim 1, as shown in FIG. 1, the air-fuel mixture drawn into the internal combustion engine M1 is exhausted. An ignition timing control device for an internal combustion engine, wherein an ignition timing for operating an ignition device M2 for ignition is controlled according to an operating state of the internal combustion engine M1.
Rotational speed detecting means M3 for detecting the rotational speed of
Load detecting means M4 for detecting the load of the internal combustion engine M1
And the first ignition for calculating the first ignition timing based on the detection results of the idle detection means M5 for detecting the idle operation state of the internal combustion engine M1, and the rotation speed detection means M3 and the load detection means M4. Timing calculation means M6, idle determination means M7 for determining idle operation based on the detection result of idle detection means M5, and predetermined determination when the idle determination means M7 determines idle operation Based on the fixed ignition timing or the detection result of the rotation speed detection means M3, the second during the idling operation
Second ignition timing calculation means M for calculating the ignition timing of
8 and the first ignition timing setting means M9 for setting the target ignition timing based on the first ignition timing when it is determined by the idle determination means M7 that the idle operation is not being performed.
When the idle determination means M7 determines that the engine is in the idle operation, the target ignition timing is set based on the first and second ignition timings with the first ignition timing as the upper limit timing on the advance side. Second ignition timing setting means M10 for
And an octane number discriminating means M11 for discriminating a difference in octane number of fuel used in the internal combustion engine M1, and a first ignition timing setting means M10 used based on the discrimination result of the octane number discriminating means M11. It is intended to include an ignition timing changing means M12 for changing the ignition timing.

In order to achieve the above-mentioned second object, in the second invention described in claim 2, as shown in FIG.
An ignition timing control device for an internal combustion engine, wherein an ignition timing for operating an ignition device M2 for igniting an air-fuel mixture sucked into the internal combustion engine M1 is controlled according to an operating state of the internal combustion engine M1. Rotational speed detection means M3 for detecting the rotational speed of the internal combustion engine M1, load detection means M4 for detecting the load of the internal combustion engine M1, and idle detection means M for detecting the idle operation state of the internal combustion engine M1.
5 and the first for calculating the first ignition timing based on the detection results of the rotation speed detecting means M3 and the load detecting means M4.
Ignition timing calculation means M6, idle determination means M7 for determining the idle operation time based on the detection result of the idle detection means M5, and when the idle determination means M7 determines the idle operation time, A second ignition timing calculating means M8 for calculating a second ignition timing during idle operation based on a predetermined fixed ignition timing or a detection result of the rotation speed detecting means M3, and idle determining means M7 during idle operation. When it is determined that it is not, the first ignition timing setting means M9 for setting the target ignition timing based on the first ignition timing, and the idle determination means M7 when it is determined that the idle operation is being performed. A second ignition timing for setting a target ignition timing based on the first and second ignition timings, with the first ignition timing being the upper limit timing on the advance side. A constant unit M10, a knock detecting means M13 for detecting the knocking of an internal combustion engine M1,
Based on the detection result of the knock detection means M13, knock learning means M14 for learning the knocking occurrence time.
And an ignition timing correction means M15 for correcting the first ignition timing used in the second ignition timing setting means M10 based on the learning result of the knock learning means M14.

[0013]

According to the structure of the first invention, as shown in FIG. 1, when the internal combustion engine M1 is in operation, the first ignition timing calculation means M6 causes the first ignition timing based on the rotational speed and the load. Is calculated. Further, the idle determination means M7 determines whether or not the idle operation is being performed based on the detection result of the idle detection means M5. Further, the octane number determination means M11 determines the difference in the octane number of the fuel.

When it is determined that the engine is not in the idle operation, the target ignition timing to be used in the ignition device M2 is set by the first ignition timing setting means M9 based on the first ignition timing. .

On the other hand, when it is determined that the engine is in the idle operation, the second ignition timing during the idle operation is
The second ignition timing calculation means M8 calculates the fixed ignition timing or the rotation speed. Further, the target ignition timing to be used in the ignition device M2 is based on the first and second ignition timings by the second ignition timing setting means M10 with the first ignition timing as the upper limit timing on the advance side. Is set. That is, the internal combustion engine M1 during idle operation
When the load is low, the target ignition timing is set based on the second ignition timing, and when the load is relatively high, the target ignition timing is relatively retarded based on the first ignition timing. Is set at the time of. At this time, the first ignition timing used in the setting means M10 is the ignition timing changing means M.
12 is changed based on the discrimination result of the octane number discriminating means M11. For example, if the octane number is low,
Compared with the case where the octane number is high, the first ignition timing is changed to a timing on the relatively retarded side.

Therefore, even if the load of the internal combustion engine M1 becomes high during idle operation, the target ignition timing will not be advanced more than necessary and the combustion of the air-fuel mixture will be stable.
Moreover, when the octane number of the fuel used changes, the above effect can be obtained according to the difference in the octane number.

According to the structure of the second aspect of the invention, as shown in FIG. 2, when the internal combustion engine M1 is in operation, the first ignition timing calculation means M6 makes the first ignition timing calculation means M6 based on the rotational speed and the load.
The ignition timing of is calculated. Further, the idle determination means M7 determines whether or not the idle operation is being performed based on the detection result of the idle detection means M5. Further, the knock learning means M14 learns the knocking occurrence time based on the detection result of the knock detection means M13. The learned value reflects the difference in the octane number of the fuel used in the internal combustion engine M1, the individual difference in the internal combustion engine M1, and the change over time.

When it is determined that the engine is not in the idle operation, the target ignition timing to be used in the ignition device M2 is set by the first ignition timing setting means M9 based on the first ignition timing. .

On the other hand, when it is determined that the engine is in the idle operation, the second ignition timing during the idle operation is
The second ignition timing calculation means M8 calculates the fixed ignition timing or the rotation speed. Further, the target ignition timing to be used in the ignition device M2 is based on the first and second ignition timings by the second ignition timing setting means M10 with the first ignition timing as the upper limit timing on the advance side. Is set. That is, the internal combustion engine M1 during idle operation
When the load is low, the target ignition timing is set based on the second ignition timing, and when the load is relatively high, the target ignition timing is relatively retarded based on the first ignition timing. Is set at the time of. At this time, the first ignition timing used in the setting means M10 is the ignition timing correction means M.
It is corrected by 15 based on the learning result of the knock learning means M14. For example, when the learning value related to the knocking occurrence timing is relatively on the retard side, the first ignition timing is on the relatively retarded side as compared with the case where the learned value is on the advance side. Corrected in time.

Therefore, even if the load of the internal combustion engine M1 becomes high during idle operation, the target ignition timing will not be advanced more than necessary, and the combustion of the air-fuel mixture will be stable.
In addition, if the octane number of the fuel used changes, or if the internal combustion engine M1 has individual differences or changes over time, the above-described effects can be obtained according to those differences.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which an ignition timing control device for an internal combustion engine according to the first and second inventions is embodied will now be described with reference to FIGS.
A detailed description will be given based on 0.

FIG. 3 is a schematic configuration diagram showing a gasoline engine system including an ignition timing control device for an internal combustion engine mounted on an automobile in this embodiment. This automobile is equipped with a known automatic transmission, power steering device, and air conditioner. A plurality of cylinder bores 3 are formed in a cylinder block 2 that constitutes an engine 1 as an internal combustion engine. A cylinder head 4 is attached to the upper side of the cylinder block 2 so as to close each cylinder bore 3. A piston 5 is vertically movably attached to each cylinder bore 3, and the piston 5 is connected to a crankshaft 1 a via a connecting rod 6. Inside the cylinder bore 3, the piston 5 and the cylinder head 4
The space surrounded by is the combustion chamber 7.

The cylinder head 4 is provided with spark plugs 8 corresponding to the respective combustion chambers 7. The head 4 is provided with an intake port 9 and an exhaust port 10 that communicate with each combustion chamber 7. Each port 9,1
An intake passage 11 and an exhaust passage 12 are connected to 0, respectively. Each of the ports 9 and 10 is provided with an intake valve 13 and an exhaust valve 14 for opening and closing, respectively. Each of the valves 13 and 14 is driven by a valve operating device (not shown) including a cam shaft in conjunction with the rotation of the crankshaft 1a. The timing for opening and closing the valves 13, 14 is synchronized with the rotation of the crankshaft 1a. That is, the valves 13 and 14 are opened and closed at a predetermined timing in synchronization with a series of strokes of the intake stroke, compression stroke, explosion / expansion stroke, and exhaust stroke of the engine 1.

An air cleaner 1 is provided on the inlet side of the intake passage 11.
5 are provided. A surge tank 16 for smoothing pulsation of air passing through the intake passage 11 is provided in the middle of the intake passage 11. On the downstream side of the surge tank 16, injectors 17 for fuel injection are provided near the intake ports 9 corresponding to the cylinder bores 3, respectively. These injectors 17 include
Fuel in a fuel tank (not shown) is pumped by a fuel pump (not shown). And the injector 1
By controlling 7 based on a predetermined command signal, the amount and timing of fuel injection into the intake port 9 are controlled. That is, the fuel injection amount control is performed. Exhaust passage 12
A catalytic converter 18 including a three-way catalyst for purifying exhaust gas is provided on the outlet side of the.

The outside air taken in from the air cleaner 15 is introduced into the intake passage 11. Each injector 1
The fuel injected from 7 forms a mixture with the outside air.
This air-fuel mixture is taken into the combustion chamber 7 when the intake valve 13 is opened in the intake stroke of the engine 1. After that, the ignition plug 8 operates in the combustion chamber 7, whereby the air-fuel mixture burns and the piston 5 operates, so that the engine 1 is provided with a driving force. The exhaust gas after combustion is guided to the exhaust passage 12 when the exhaust valve 14 is opened in the exhaust stroke of the engine 1, purified by the catalytic converter 18, and then discharged to the outside.

On the upstream side of the surge tank 16, there is provided a throttle valve 19 which operates in conjunction with the operation of an accelerator pedal (not shown). By adjusting the opening degree (throttle opening degree) TA of the valve 19, the intake amount of outside air into the intake passage 11, that is, the intake amount Q is adjusted.

In the vicinity of the throttle valve 19, a throttle sensor 3 as an idle detecting means in the present invention is provided.
1 is provided. This sensor 31 detects the throttle opening TA and outputs a signal according to the detection result.
A well-known idle switch (not shown) is built in the sensor 31. This idle switch is turned on when the throttle valve 19 is fully closed,
An idle signal IDL indicating that is output. An air flow meter 32 is provided downstream of the air cleaner 15. The meter 32 detects the intake air amount Q taken into the intake passage 11 and outputs a signal according to the detection result. An intake air temperature sensor 33 is provided near the air cleaner 15. The sensor 33 detects the temperature of intake air (intake air temperature) THA taken into the intake passage 11 and outputs a signal corresponding to the detection result.

An oxygen sensor 34 is provided in the middle of the exhaust passage 12.
Is provided. The sensor 34 detects the oxygen concentration OX in the exhaust gas and outputs a signal according to the detection result.
A water temperature sensor 35 is provided in the cylinder block 2. The sensor 35 detects the temperature (cooling water temperature) THW of the cooling water of the engine 1 and outputs a signal according to the detection result.

Spark plug 8 corresponding to each cylinder bore 3
The ignition signal distributed by the distributor 20 is applied to. The distributor 20 distributes the high voltage output from the igniter 21 to each spark plug 8 in synchronization with the rotation angle of the crankshaft 1a, that is, the crank angle (CA). The ignition timing of each spark plug 8 is determined by the output timing of the high voltage output from the igniter 21. In this embodiment, each of the spark plugs 8, the distributor 20 and the igniter 2 described above are used.
1 constitutes the ignition device of the present invention. Then, the ignition timing in the spark plug 8 is controlled by controlling the igniter 21 based on a predetermined command signal. That is, ignition timing control is performed.

The distributor 20 has a built-in rotor (not shown) which is rotated in association with the rotation of the crankshaft 1a. The distributor 20 has
A rotation speed sensor 36 as a rotation speed detecting means in the present invention and a cylinder discrimination sensor 37 are provided. The rotation speed sensor 36 detects the rotation speed of the engine 1 (engine rotation speed) NE from the rotation of the rotor, and outputs a signal according to the detection result. The cylinder discrimination sensor 37 also detects a reference position at a crank angle from the rotation of the rotor at a predetermined ratio, and outputs a reference signal GP indicating the detection result. In this embodiment, the crankshaft 1a rotates twice for a series of strokes of the engine 1, and the rotation speed sensor 36 detects the crank angle at a rate of 30 ° per pulse. In addition, the cylinder discrimination sensor 37 is set to 1
The crank angle is detected at a rate of 360 ° per pulse. In this embodiment, the air flow meter 32 and the rotation speed sensor 36 constitute the load detecting means in the present invention.

Further, in this embodiment, a knock sensor 38 constituting the knock detecting means of the present invention is attached to the cylinder block 2. This sensor 38
Detects a vibration generated in the engine 1 due to knocking or the like, and outputs a knock signal KCS according to the detection result.

In addition, in this embodiment, the intake passage 11 is provided with a bypass passage 22. This passage 22 bypasses the throttle valve 19 and connects the upstream side and the downstream side of the valve 19 to each other. A well-known linear solenoid type idle speed control valve (ISCV) 23 is provided in the passage 22. This ISCV23
Is operated to stabilize the throttle valve 19 during idle operation when the throttle valve 19 is fully closed. Then, by controlling the ISCV 23 based on a predetermined command signal during idle operation, the opening degree of the bypass passage 22 is adjusted and the intake air amount Q taken into the combustion chamber 7 through the bypass passage 22 is adjusted, and the engine speed NE Is controlled. That is, idle speed control is performed.

In this embodiment, an electronic control unit (EC
U) 51 inputs signals detected by the sensors 31 to 38 described above. Then, the ECU 51 executes the ignition timing control, the fuel injection amount control, the idle rotation speed control, etc. of the engine 1 on the basis of these detection signals, in order to execute the injectors 17, the igniters 21 and I, respectively.
Controls each of the SCVs 23. In this example, E
The CU 51 constitutes first and second ignition timing calculating means, first and second ignition timing setting means, octane number determining means, ignition timing changing means, knock learning means, and ignition timing correcting means in the present invention. .

As shown in the block diagram of FIG. 4, the ECU 5
1 is a central processing unit (CPU) 52, a read-only memory (R
OM) 53, random access memory (RAM) 54,
The backup RAM 55 and the timer counter 56 are provided. In the ECU 51, these units 52 to 56, the external input circuit 57, the external output circuit 58 and the like are connected by a bus 59 to form a theoretical operation circuit.

The ROM 53 has the above-mentioned ignition timing control,
Predetermined programs and the like relating to fuel injection amount control, idle rotation speed control, and the like are stored in advance. The calculation result of the CPU 52 and the like are temporarily stored in the RAM 54. Data stored in advance is stored in the backup RAM 55. The timer counter 56 simultaneously performs a plurality of counting operations.

The above-mentioned sensors 31 to 38 are connected to the external input circuit 57, respectively. The external output circuit 58 includes the injectors 17, igniters 21 and I.
The SCVs 23 are respectively connected. And CPU
Reference numeral 52 reads the detection signals of the sensors 31 to 38 input through the external input circuit 57 as input values. C
The PU 51 uses the input values as a basis for each member 17, 2
1 and 23 are controlled.

Next, the processing contents of the ignition timing control executed by the ECU 51 in the above gasoline engine system will be described with reference to FIGS. Figure 5
4 is a flowchart showing an "ignition timing calculation routine" executed by the ECU 51, which is periodically executed at predetermined intervals.

When the processing shifts to this routine, first, at step 100, the idle signal IDL, the intake air amount Q, and the engine speed NE are read based on the detection signals of the sensors 31, 32, 36. At the same time, the value of the knock delay amount AKB is read. This knock delay amount AKB is calculated by a separate "AKB calculation routine" described later. The knock retard amount AKB is for reflecting the difference in the octane number of the fuel used in the engine 1 to correct the ignition timing control during the idle operation.

Next, at step 110, the first basic ignition timing ABF is calculated based on the intake air amount Q and the engine speed NE. This basic ignition timing ABF is set based on the crank angle as a timing earlier than the top dead center TDC as a reference. Here, the value of the load on the engine 1 (the amount of intake air per revolution of the engine 1 = Q / NE) and the value of the engine speed NE, which are obtained from the relationship between the intake air amount Q and the engine speed NE, are reflected. Then, the basic ignition timing ABF is calculated by a known method with reference to a predetermined two-dimensional map (not shown). This basic ignition timing ABF is used for ignition timing control during normal operation that is not originally during idle operation. However, as will be described later, this basic ignition timing ABF
Is used to limit the ignition timing in order to prevent the ignition timing from being over-advanced during idle operation. Therefore, the basic ignition timing ABF is calculated regardless of whether or not the engine is idling. In this embodiment, the ECU 51 that executes the processing of step 110
Corresponds to the first ignition timing calculation means in the present invention.

Next, at step 120, it is judged if the idle signal IDL is "on". That is,
It is determined whether or not the engine is in an idle operation in which the throttle valve 19 is fully closed. Here, if the engine 1 is in normal operation, the process proceeds to step 130, and if it is in idle operation, the process proceeds to step 121. In this embodiment, the ECU 51 that executes the processing of step 120 corresponds to the idle determination means of the present invention.

In step 130, step 11
At 0, the first basic ignition timing ABF calculated this time is temporarily stored in the RAM 54 as the target ignition timing ABS, and the subsequent processing is temporarily terminated. In this embodiment, the ECU 51 that executes the processing of the above step 130 corresponds to the first ignition timing setting means in the present invention.

In step 121, it is determined whether or not the count value C0 in the timer counter 56 is "3 seconds" or more. The count value C0 indicates the elapsed time after the engine 1 is started. Engine 1
Until a predetermined time elapses after the engine is started, the rotation fluctuation of the engine 1 is large, and the idle correction value AID based on the rotation fluctuation cannot be accurately calculated. Here, in order to avoid that, the magnitude of the count value C0 is determined. When the count value C0 is less than “3 seconds”,
The process proceeds to step 125, and the count value C0 is "3.
If it is “seconds” or more, the process proceeds to step 122.

On the other hand, in step 122 after shifting from step 121, the smoothed value NE as the weighted average value is calculated based on the engine speed NE read this time.
Calculate M. Further, in step 123, the rotational speed deviation ΔN is calculated from the difference between the current smoothed value NEM and the current engine rotational speed NE.

Then, in step 124, the idle correction value AI is calculated based on the rotational speed deviation ΔN calculated this time.
D is calculated and the calculation result is stored in the RAM 54. Here, the idle correction value AID is calculated with reference to a map as shown in FIG. This idle correction value AID is
When the engine 1 is idle, the engine rotation speed NE increases when the ignition timing is advanced under the condition that the throttle opening TA and the air-fuel ratio are constant, and the engine rotation speed NE decreases when the ignition timing is retarded. This is required in consideration of the characteristics. Then, the engine rotational speed NE during idle operation, that is, the idle rotational speed is compared with a predetermined target rotational speed (or an average value of the idle rotational speeds), and when the idle rotational speed becomes lower than the target rotational speed. Is a value for stabilizing the idle rotation speed by advancing the ignition timing and retarding the ignition timing when the idle rotation speed rises above the target rotation speed.

The process moves from step 121 to step 12
In 5, the idle correction value AID is set to “0” and stored in the RAM 54. In this embodiment, the ECU 51 that executes the processes of steps 120 to 125 described above.
Corresponds to an idle correction value calculation means for calculating an idle correction value AID for correcting a target ignition timing ABS, which will be described later, in accordance with a change in the engine speed NE during idle operation.

Next, at step 140, the second basic ignition timing ABN is calculated based on the engine speed NE read this time. This basic ignition timing ABN
Is set based on the crank angle as a time earlier than the top dead center TDC as a reference. Here, this basic ignition timing ABN is calculated with reference to a map as shown in FIG. In this map, the "engine stall area" and the "deceleration area" related to the engine speed NE
In the range of, the basic ignition timing ABN is the engine speed N
It changes continuously with the change of E, and the basic ignition timing ABN changes little with respect to the change of the engine speed NE in the range of the "idle region". This basic ignition timing ABN is used to set the ignition timing during idle operation,
It is calculated only during idle operation. In this embodiment, the ECU 51 that executes the processing of step 140 corresponds to the second ignition timing calculation means of the present invention.

At step 150, the idle correction value AI is added to the value of the second basic ignition timing ABN obtained this time.
By adding D, the second
The corrected basic ignition timing α is calculated. Also, step 16
At 0, the first basic ignition timing AB calculated this time
By subtracting the value of the knock retard amount AKB read this time from the value of F, the first corrected basic ignition timing β during idle operation is calculated.

In step 170, it is determined whether the second corrected basic ignition timing α is larger than the first corrected basic ignition timing β. That is, it is determined which is on the advance side with reference to the top dead center TDC. Here, if the second corrected basic ignition timing α is not larger than the first corrected basic ignition timing β, the process proceeds to step 180, and in the opposite case, the process proceeds to step 190. Transition. Here, when the load on the engine 1 during the idle operation is small, the second corrected basic ignition timing α does not become larger than the first corrected basic ignition timing β, so the process proceeds to step 180. To do. In contrast,
If the load on the engine 1 during idling is large, the second corrected basic ignition timing α becomes larger than the first corrected basic ignition timing β, and the process proceeds to step 19
Move to 0.

At step 180, since the second corrected basic ignition timing α is on the retard side of the first corrected basic ignition timing β, the corrected basic ignition timing α is set to the target ignition timing. The data is temporarily stored in the RAM 54 as ABS, and the subsequent processing is temporarily ended.

On the other hand, in step 190, since the second corrected basic ignition timing α is on the advance side of the first corrected basic ignition timing β, the corrected basic ignition timing β is idled. The correction value AID is subtracted, and the subtraction result is temporarily stored in the RAM 54 as the target ignition timing ABS.
The subsequent processing is once ended.

That is, in the processing of steps 170 to 190, when the load on the engine 1 is large, the second corrected basic ignition timing α is a value on the advance side of the first corrected basic ignition timing β. Therefore, the first corrected basic ignition timing β is set as the upper limit timing on the advance side so that the second corrected basic ignition timing α is limited. In this embodiment, E which executes the processing of steps 170 to 190 described above.
The CU 51 corresponds to the second ignition timing setting means in the present invention.

Thereafter, the ECU 51 drives the igniter 21 based on the value of the target ignition timing ABS in accordance with a separate processing routine to operate each spark plug 8 and ignite the fuel. That is, the ignition timing is actually output based on the target ignition timing ABS. Since the processing contents related to the ignition timing output are generally known techniques, the description thereof is omitted here.

Next, the calculation of the knock delay reflection amount AKN used to control the knocking generated in the engine 1 will be described. FIG. 7 is a flowchart showing an “AKN calculation routine” executed by the ECU 51, which is periodically executed at predetermined intervals.

When the processing shifts to this routine, first, at step 200, the sensors 31, 32, 35,
Based on the detection signals of 36 and 38, the idle signal IDL,
The intake air amount Q, the cooling water temperature THW, the engine speed NE, and the knock signal KCS are read.

Subsequently, in step 300, the knock retard amount AKB described above is calculated. This knock delay amount A
The calculation of KB is performed according to a separate "AKB calculation routine" as shown in the flowchart of FIG.

That is, at step 301, the maximum retardation amount AKMX is calculated based on the read intake air amount Q and the engine speed NE. This calculation is performed by referring to a predetermined two-dimensional map (not shown) that reflects the value of the load related to the engine 1 obtained from the relationship between the intake air amount Q and the engine speed NE and the value of the engine speed NE. Be seen.

Subsequently, in step 302, it is determined whether or not the idle signal IDL is "on". That is, it is determined whether or not the engine is idle. here,
If the engine 1 is in normal operation, the process proceeds to step 303, and if it is in idle operation, the process proceeds to step 304. In this embodiment, the ECU 51 that executes the process of step 302 also corresponds to the idle determination means of the present invention.

In step 303, the knock control amount AKC is set to "0 ° CA" and stored in the RAM 54. After that, the process proceeds to step 317. On the other hand, in step 304, it is determined whether the operating state of the engine 1 is in the knock control region where knock control should be performed. This knock control region corresponds to a range preset with respect to the engine speed NE and the engine load.

If the operating state of the engine 1 is not in the knock control region, the process of step 303 is executed and then the process proceeds to step 317. If the operating state of the engine 1 is in the knock control region, the process proceeds to step 3
Move to 05.

In step 305, it is determined whether the engine 1 knocks. This knocking determination is made based on the knock signal KCS. here,
If there is knocking, in step 306,
"0.4 ° CA" is added to the value of the knock control amount AKC this time to set a new knock control amount AKC. If there is no knocking, in step 307, another count value C1 in the timer counter 56 is set to "300 m".
It is determined whether it is more than "second". This count value C1
Is a value counted to advance the knock control amount AKC at predetermined time intervals when there is no knocking.

Then, the count value C1 is "300 m.
If it is less than “second”, the process is directly performed in step 31.
Move to 0. If the count value C1 is "300 msec" or more, in step 308, "0.08 ° CA" is subtracted from the value of the current knock control amount AKC to set a new knock control amount AKC. Furthermore, step 3
At 09, after resetting the count value C1 to "0", the process proceeds to step 310.

In step 310, it is determined whether or not the operating state of the engine 1 is in the learning region where knocking learning control should be performed. This learning region corresponds to a range preset with respect to the engine speed NE and the engine load.

If the operating state of the engine 1 is not in the knocking learning region, the process proceeds to step 317.
Move to. If the operating state of the engine 1 is in the knocking learning region, the process proceeds to step 311.

In step 311, another count value C2 in the timer counter 56 is "500 m".
It is determined whether it is more than "second". This count value C2
Is a value that is counted in order to learn and update a knock learning value AKG, which will be described later, every predetermined time.

Then, the count value C2 is "500 m.
If it is less than “second”, the process is directly performed in step 31.
Move to 7. If the count value C2 is “500 msec” or more, in step 312, the count value C2
After resetting 2 to “0”, the process proceeds to step 313. In step 313, it is determined whether or not the value of the knock control amount AKC obtained as described above is “2 ° CA” or more. Here, when the value of the knock control amount AKC is less than “2 ° CA”, in step 314, “0.1 ° CA” is added to the current knock learning value AGK, and the addition result is used as a new knock. Set as the learning value AGK. Then, the process proceeds to step 317.

On the other hand, in step 313, if the value of the knock control amount AKC is “2 ° CA” or more, the process proceeds to step 315. And step 31
5, the value of the knock control amount AKC is also “4 ° C.
It is determined whether it is less than "A". Here, when the value of the knock control amount AKC is equal to or larger than “4 ° CA”, in step 316, “0.1 ° CA” is subtracted from the current knock learning value AGK, and the subtraction result is newly updated. Set as knock learning value AGK. Then, the process proceeds to step 317. The value of knock control amount AKC is “4 °
If it is less than “CA”, the process is directly performed in step 3
Go to 17.

Here, the knock learning value AGK calculated as described above reflects not only the difference in the octane number of the fuel but also the individual difference of the engine 1 and the change over time. Then, steps 303, 310, 311, 314 to 31
In step 317 after shifting from 6, based on the parameters AKMX, AGK, and AKC obtained this time,
The knock retard amount AKB is calculated according to the following calculation formula, and the subsequent processing is once ended.

AKB = AKMX-AGK + AKC That is, the knock retard amount AKB is calculated as a retard value with respect to the target ignition timing ABS, as shown in FIG.

As described above, the knock retard amount ABK is calculated, and the knock control amount AKC and the knock learning value AGK are calculated in association therewith. In this example,
ECU for executing the processing of steps 302 to 316 described above
Reference numeral 51 corresponds to the knock learning means in the present invention. Then, in the series of processes in steps 302 to 316, the value of the knock control amount AKC is "2" based on the presence or absence of knocking.
Knock learning value A to be a value in the range of "~ 4 ° CA"
GK is updated.

Here, the fuel used for the engine 1 is
It may be changed by a general user between premium gasoline having a high octane number and regular gasoline having a low octane number. Then, when the engine 1 is of the premium specification, the ignition timing control is performed based on the second basic ignition timing ABN adapted to the premium specification. However, when the fuel is changed to regular gasoline, knocking frequently occurs because the limit timing of knocking related to the fuel is relatively on the retard side. Therefore, the knock control amount AKC becomes large, and the knock learning value AGK becomes small to some extent. Therefore, by using the knock control amount AKC or the magnitude of the knock learning value AGK, it becomes possible to determine the use of the legara gasoline.

On the contrary, when the fuel is changed to premium gasoline when the ignition timing control is performed based on the second basic ignition timing ABN of the regular specification,
Since the limit time for knocking the fuel is relatively on the advance side, knocking is reduced. For this reason,
The knock control amount AKC becomes smaller, and the knock learning value AGK
Grows to some extent. Therefore, the knock control amount AKC,
Alternatively, it is possible to determine the use of premium gasoline by determining the magnitude of knock learning value AGK.

In this embodiment, the above step 313,
At 315, the magnitude of knock control amount AKC is determined, and based on the determination result, the knock learning value is updated at steps 314 and 316. Therefore, the ECU 51 that executes the processing of these steps 313 to 316
Corresponds to the octane number determining means in the present invention.

Therefore, the values of the knock retard amount AKB and the knock control amount AKC and the knock learning value AGK are reflected in the value of the knock retard amount AKB, which in turn reflects the use of premium gasoline or regular gasoline. To be done.

In this embodiment, since the value of the knock retard amount AKB in the flowchart of FIG. 5 is used to calculate the first corrected basic ignition timing β, the target used during idle operation is set. The use of premium gasoline or regular gasoline is reflected in the ignition timing ABS. Therefore, the ECU 51 that executes step 160 in the flowchart of FIG. 5 corresponds to the ignition timing changing means and the ignition timing correcting means in the present invention.

Returning again to the flowchart of FIG. 7, after the processing of step 300 is performed as described above, in step 210, the cooling water temperature THW read this time is read.
It is determined whether the value of is lower than a predetermined reference value TH1. This determination is made in order to know whether the engine 1 is cold, and therefore the reference value TH1 is set to an appropriate value (for example, "60 ° C"). here,
If the cooling water temperature THW is not lower than the reference value TH1, the process directly proceeds to step 230. Cooling water temperature TH
If W is lower than the reference value TH1, step 220
At the knock delay amount AKB calculated this time,
CA ”is added to correct the knock delay amount AKB. This is because the knock feedback control based on the detection signal of the knock sensor 38 is not performed when the engine 1 is cold,
Since the knock learning value AGK itself has low reliability,
Knock learning value AG so that only "2 ° CA" is on the retard side
K is corrected.

Then, the routine proceeds from step 210 or 220 to step 230, where it is determined whether or not the idle signal IDL is "ON", that is, whether or not the idle operation is being performed. Here, when the engine 1 is in the normal operation, in step 240, the value of the knock retard angle amount AKB calculated in step 220 is set as the knock retard angle reflection amount ANK, and the subsequent processing is temporarily terminated. . If the engine 1 is in idle operation, step 2
At 50, "0" is set as the knock delay angle reflection amount AKN, and the subsequent processing is temporarily terminated.

The knock delay reflection amount AKN is calculated as described above. This knock delay reflection amount AKN is calculated by the engine 1
During the normal operation of, the target ignition timing ABS is used together with the above-described target ignition timing ABS to determine the required ignition timing ACA that should be finally used for performing the ignition timing control. That is, the required ignition timing ACA is calculated according to the following calculation formula.

ACA = ABS + ACL + AEGR-AKN Here, ACL is a correction value obtained according to the warm-up state of the engine 1. AEGR is the exhaust gas recirculation amount (E
It is a correction value obtained according to the GR amount).

According to the above configuration, during the normal operation of the engine 1, the final required ignition timing ACA to be used in the ignition timing control is set based on the first basic ignition timing ABF. On the other hand, during idle operation of the engine 1, the second basic ignition timing ABN to be used during the idle operation is calculated based on the engine speed NE. In this embodiment, the ECU 51
By controlling the ISCV 23, the idle rotation speed control is executed, so that the idle rotation speed is controlled to a predetermined value and is controlled according to a change in the engine load. Further, the final target ignition timing ABS to be finally used in the ignition timing control is the first and second basic ignition timings ABF, ABN with the first basic ignition timing ABF as the upper limit timing on the advance side. It is set based on.

That is, when the engine load during idle operation is low, the target ignition timing ABS is set based on the second basic ignition timing ABN, and when the engine load is relatively high, the target ignition timing ABS is The timing is set relatively on the retard side based on the first basic ignition timing ABF. At this time, the first basic ignition timing ABF used in the above setting is changed based on the difference in octane number of the fuel used in the engine 1, that is, the difference in premium gasoline or regular gasoline.

For example, when regular gasoline with a low octane number is used in the engine 1, the value of the first basic ignition timing ABF is relatively higher than when premium gasoline with a high octane number is used. It is changed to the timing of the retard side.

Therefore, even if the engine load becomes high during idle operation, the target ignition timing ABS will not advance more than necessary and the combustion of the air-fuel mixture will be stable in each combustion chamber 4. Moreover, when the octane number of the fuel used changes, the above effect can be obtained according to the difference in the octane number.

As a result, in the idle operation of the engine 1, even if the engine load increases due to the operation of the automatic transmission, the power steering device, the air conditioner, etc., the actual ignition timing advances more than necessary. It is possible to secure the idle stability of the engine 1 in a range that does not satisfy the above condition, prevent the occurrence of knocking, and improve the engine stalling resistance. Furthermore, ensuring the idle stability and preventing the occurrence of knocking, the engine 1
This can be done by coping with changes in the type of fuel used in. That is, even if the user of the vehicle arbitrarily changes the fuel used between regular gasoline and premium gasoline, it is possible to ensure idle stability and prevent knocking.

Further, in this embodiment, the first basic ignition timing ABF is the knock learning value AGK by the knock learning control.
It is corrected based on. For example, when the knock learning value AGK is on the relatively retarded side, the first basic ignition timing ABF is on the relatively retarded side as compared to when the learned value AGK is on the advanced side. Is corrected to.

Therefore, when the engine load becomes high during idle operation, the above-described action can be obtained in accordance with the difference in the individual components of the engine 1 and the difference in changes over time. As a result, the above-described idle stability can be ensured and knocking can be prevented with higher accuracy when the load increases during idle operation by the amount of correction of the individual difference of the engine 1 and the change over time.

In addition, in this embodiment, in the flowchart of FIG. 5, the value of the second basic ignition timing ABN is corrected by the idle correction value AID corresponding to the minute change of the engine speed NE in step 150. , Step 19
When the target ignition timing ABS is 0, the idle correction value AID is also set.
I am correcting with. Therefore, the state of the engine speed NE during idling is stabilized by the amount of the correction, and the idling stability can be further improved.

The present invention can be embodied in the following other embodiments. In another example below,
It is possible to obtain the same actions and effects as those of the above-mentioned embodiment. (1) In the above embodiment, the second basic ignition timing ABN during idling is calculated based on the magnitude of the engine speed NE, but it may be calculated based on a predetermined fixed ignition timing.

(2) In the above embodiment, the maximum retardation amount AKMX is calculated on the basis of the intake air amount Q and the engine speed NE in step 301 of the flow chart of FIG.

On the other hand, as shown in FIG. 11, the minimum ignition timing AKGD and the first basic ignition timing ABF are set by a two-dimensional map based on the relationship between the engine load and the ignition timing. Then, by referring to the map, the maximum ignition retard amount AKMX may be calculated by subtracting the minimum ignition timing AKGD from the first basic ignition timing ABF.

(3) In the above-described embodiment, the ignition timing control device of the present invention is applied to the "el-Jetronic" type engine 1 using the air flow meter 32. However, the "di-Jetronic" using the vacuum sensor is used. It can also be applied to "type" engines.

(4) In the above embodiment, the knock control amount AK
The octane number of the fuel is determined based on C or the knock learning value AGK, and the target ignition timing ABS is corrected / changed by reflecting the determination result.

On the other hand, the operating state of the switch or the like operated by the user of the automobile according to the difference in the octane number of the fuel, the knock control amount AKC or the knock learning value AG.
Based on K, the ECU (octane number determination means) determines the type of fuel currently in use. Further, a plurality of maps in which the relationship between the engine speed NE and the engine load and the first basic ignition timing ABF for normal operation are set are prepared in advance according to the type of fuel. And the ECU
A plurality of maps are selectively referred to by the (ignition timing changing means) based on the determination result, and the second basic ignition timing ABN for idle operation is retarded based on the referred first basic ignition timing ABF. It is also possible to add restrictions on the side.

(5) In the above embodiment, as shown in FIG. 10, the ignition timing control is performed by correcting the target ignition timing ABS on the basis of the knock retard amount AKB reflecting the parameters AKMX, AGK, and AKC. The knock learning value AGK is reflected in the required ignition timing ACA that should be finally used for performing.

On the other hand, as shown in FIG. 12, the target ignition timing A based on the knock retarded reflection amount AKN determined based on the knock learning value AGK and the knock control amount AKC.
By correcting BS, the final required ignition timing AC
The knock learning value AGK may be reflected in A. Here, the knock retard reflection amount AKN is smaller than the maximum retard amount AKMX. Further, the knock learning value AGK is the knock control amount A
When KC is in the range of “2 to 4 ° CA”, “0.1
It is increased / decreased and corrected in units of "CA".

(6) In the above embodiment, the ignition timing control device of the present invention is applied to a gasoline engine as an internal combustion engine, but this ignition timing control device may be applied to an LPG engine.

Although the respective embodiments of the present invention have been described above, it is noted that the respective embodiments include the following various embodiments relating to the technical idea described in the scope of claims. The effect is described in.

(A) In the invention according to claim 1 or 2, an idle correction value for calculating an idle correction value for correcting the target ignition timing according to a change in the rotational speed of the internal combustion engine during idle operation. An ignition timing control device for an internal combustion engine provided with a calculation means.

According to this structure, the idle stability can be further improved by the idle correction value. still,
In this specification, means and members related to the constitution of the invention are defined as follows.

(A) The learning means a method of determining a better control method by making use of past control experience, and the control device itself evaluates and stores the control result up to now, and based on the evaluation. This includes modifying the storage of parameters or control logic within the controller.

[0100]

According to the first invention described in claim 1,
During operation of the internal combustion engine, the first ignition timing is calculated based on the rotational speed and load, and during idle operation, the second ignition timing is determined based on a predetermined fixed ignition timing or the rotational speed of the engine.
The ignition timing of is calculated. And during idle driving,
The target ignition timing is set based on the first and second ignition timings with the first ignition timing as the upper limit timing on the advance side. Further, during the idling operation, the first ignition timing is changed based on the determination result of the fuel octane number.

Therefore, even if the engine load becomes high during idle operation, the target ignition timing does not advance more than necessary, combustion of the air-fuel mixture becomes stable, and these effects cause differences in the octane number of the fuel used. Obtained together. As a result, even if the engine load increases during idle operation, idle stability can be ensured within a range that does not lead to an advanced angle more than necessary, and knocking can be prevented. Furthermore,
The effect is that they can be dealt with by changing the type of fuel used.

According to the second aspect of the present invention, when the internal combustion engine is in operation, the first ignition timing is calculated based on the rotational speed and load, and during idle operation, a predetermined fixed ignition timing, Alternatively, the second ignition timing is calculated based on the engine speed. Then, during idle operation, the first ignition timing is set as the upper limit timing on the advance side, and the first and second ignition timings are set.
The target ignition timing is set based on the ignition timing of. Furthermore,
During idle driving, based on the learning result of knocking,
The first ignition timing is corrected.

Therefore, even if the engine load becomes high during idle operation, the target ignition timing does not lead to an undesired advance, the combustion of the air-fuel mixture is stabilized, and their effects are due to the difference in octane number of the fuel used. It can be obtained according to the individual differences of the internal combustion engine and changes over time. As a result, even if the engine load increases during idle operation, idle stability can be ensured within a range that does not lead to an advanced angle more than necessary, and knocking can be prevented. Furthermore, there is an effect that it is possible to deal with them by changing the type of fuel used, the difference in the individual characteristics of the engine, and the change over time.

[Brief description of drawings]

FIG. 1 is a conceptual configuration diagram illustrating a basic conceptual configuration of a first invention.

FIG. 2 is a conceptual configuration diagram illustrating a basic conceptual configuration of a second invention.

FIG. 3 is a schematic configuration diagram showing a gasoline engine system including an ignition timing control device for an internal combustion engine according to the present invention in one embodiment embodying the first and second inventions.

FIG. 4 is a block diagram showing a configuration of an ECU and the like in one embodiment.

FIG. 5 is a flowchart showing an “ignition timing calculation routine” executed by the ECU in the embodiment.

FIG. 6 is a map showing a relationship between a rotation speed deviation (ΔN) and an idle correction value (AID) in one embodiment.

FIG. 7 is a flowchart showing an “AKN calculation routine” executed by the ECU in the embodiment.

FIG. 8 is a flowchart showing an “AKB calculation routine” executed by the ECU in the embodiment.

FIG. 9 shows an engine speed (N
It is a map which shows the relationship between E) and the 2nd basic ignition timing (ABN).

FIG. 10 shows an example of a knock delay amount (AK
It is explanatory drawing which shows the calculation method of B).

FIG. 11 shows the maximum retardation amount (AKM) in another embodiment.
It is a map which shows the calculation method of X).

FIG. 12 shows a target ignition timing (AB
It is explanatory drawing which shows how to reflect a knock learning value (AGK) etc. with respect to S).

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine as an internal combustion engine, 8 ... Spark plug, 20
... Distributor, 21 ... Igniter (8, 20,
Reference numeral 21 constitutes an ignition device, 31 ... Throttle sensor (31 constitutes idle detection means), 32 ... Air flow meter, 36 ... Rotation speed sensor (36 constitutes rotation speed detection means, and 32 and 36 are loads. Detection unit), 38 ... Knock sensor (38 forms knock detection unit), 51 ... ECU (51 is idle determination unit, first and second ignition timing calculation unit, first and second ignition) Timing setting means, octane number determination means, ignition timing changing means,
It constitutes knock learning means and ignition timing correction means).

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location F02P 5/152 5/153 F02P 5/15 K

Claims (2)

[Claims] 1. An ignition timing control device for an internal combustion engine, wherein an ignition timing for operating an ignition device for igniting an air-fuel mixture sucked into the internal combustion engine is controlled according to an operating state of the internal combustion engine. There, rotation speed detection means for detecting the rotation speed of the internal combustion engine, load detection means for detecting the load of the internal combustion engine, idle detection means for detecting the idle operation state of the internal combustion engine A first ignition timing calculation means for calculating a first ignition timing based on the detection results of the rotation speed detection means and the load detection means, and during idle operation based on the detection results of the idle detection means. And a predetermined fixed ignition timing or the rotation speed detected when the idle determination means determines that the engine is in idle operation. Second ignition timing calculation means for calculating a second ignition timing during idle operation based on the detection result of the means, and the first ignition timing calculation means when the idle determination means determines that it is not during idle operation. A first ignition timing setting means for setting a target ignition timing based on the ignition timing; and, when the idle determination means determines that the engine is in an idle operation, the first ignition timing is set to an advanced side. As an upper limit timing, a second ignition timing setting means for setting a target ignition timing based on the first and second ignition timings, and for determining a difference in octane number of fuel used in the internal combustion engine The octane number determining means, and the second value based on the determination result of the octane number determining means.
And an ignition timing changing means for changing the first ignition timing used in the ignition timing setting means of. 2. An ignition timing control device for an internal combustion engine, wherein an ignition timing for operating an ignition device for igniting an air-fuel mixture drawn into the internal combustion engine is controlled according to an operating state of the internal combustion engine. There, rotation speed detection means for detecting the rotation speed of the internal combustion engine, load detection means for detecting the load of the internal combustion engine, idle detection means for detecting the idle operation state of the internal combustion engine A first ignition timing calculation means for calculating a first ignition timing based on the detection results of the rotation speed detection means and the load detection means, and during idle operation based on the detection results of the idle detection means. And a predetermined fixed ignition timing or the rotation speed detected when the idle determination means determines that the engine is in idle operation. Second ignition timing calculation means for calculating a second ignition timing during idle operation based on the detection result of the means; and the first ignition timing calculation means when the idle determination means determines that the idle operation is not being performed. A first ignition timing setting means for setting a target ignition timing based on the ignition timing; and, when the idle determination means determines that the engine is in an idle operation, the first ignition timing is set to an advanced side. Second ignition timing setting means for setting a target ignition timing based on the first and second ignition timings as an upper limit timing; knock detecting means for detecting knocking of the internal combustion engine; Knock learning means for learning the knocking occurrence timing based on the detection result of the detection means, and the second ignition timing setting hand based on the learning result of the knock learning means. Ignition timing control apparatus for an internal combustion engine characterized by comprising an ignition timing correction means for correcting the first ignition timing used in.