JPH01280677A - Ignition timing control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent the occurrence of knocking after the sudden change of a load, by a method wherein based on a change amount of a load for an internal combustion engine, the period of a sudden change in a load is decided, and after lapse of a load sudden change period, an ignition timing is delayed by a given period for correction. CONSTITUTION:The ignition timing of an internal combustion engine M1 is controlled according to the number of revolutions and a load. In this case, a change amount of a load is calculated by a means M2. Based on a calculated change amount of a load, a sudden change period in which a load is changed suddenly is decided by a means M3. After lapse of a sudden change period, the ignition timing of an internal combustion engine M1 is delayed by a given period for correction by means of a means M4. This constitution prevents the occurrence of knocking after the sudden change of a load without the occurrence of a trouble, e.g., an increase in the size of an ignition system device and sacrifice of an output.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention [Industrial Application Field] The present invention relates to an ignition timing control device for an internal combustion engine that suppresses knocking that occurs due to load fluctuations in the internal combustion engine.

[Prior Art] Various devices have been known that advance or retard ignition timing to suppress knocking that occurs in internal combustion engines, thereby improving fuel efficiency and output characteristics. For example, when there is a sudden change in operating conditions, the knocking condition changes rapidly as the operating conditions change, causing a response delay in the ignition timing control system. A device has been proposed that suppresses the occurrence of transient knocking by detecting a transient period in which the pressure, intake air amount, etc. are changing, and retarding the ignition timing during this transient period (
Japanese Patent Publication No. 57-99269).

In addition, the occurrence of knocking is closely related to the air-fuel ratio, and as shown in Figure 7, for example, when the intake pressure suddenly increases during acceleration, the air-fuel ratio tends to lean and knocking occurs. This condition is likely to occur. The control speed has been improved by improving the response of conventional fuel injection valves and the response of electronic control circuits, etc., and as shown in Fig. 8, even during a transient period when the intake pressure changes rapidly, , the air-fuel ratio changes less.

Through improvements in ignition time control, fuel injection control, etc., the occurrence of knocking has almost been eliminated during transient operation when the intake air pressure as a load changes rapidly, such as during acceleration.

[Problems to be Solved by the Invention] These conventional devices can suppress the occurrence of knocking while the intake pressure as a load changes rapidly. However, as the ignition timing becomes later, the air density in the combustion chamber at the time of ignition increases, and the fuel falls in the direction of the engine, causing the air-fuel ratio near the spark plug to become lean. There is. In such a case, if the ignition time is delayed, ignition will be executed when the air density is high and the air-fuel ratio is lean, which will reduce the demand required for ignition by the spark plug. There was a problem in that the voltage became higher and the ignition system equipment became larger. Additionally, since the ignition time is retarded at the beginning of acceleration, the output of the internal combustion engine is sacrificed, resulting in poor engine speed during racing. Furthermore, due to improvements in control response, etc., it was possible to suppress the occurrence of knocking when the intake pressure was changing rapidly. However, as shown in Figure 8, the intake pressure as a load changes rapidly, from a certain intake pressure to a higher intake pressure, and at that high intake pressure, it becomes almost a steady state. A problem has arisen in that during a certain period T, for example, knocking may occur due to some reason such as the air-fuel ratio changing and becoming leaner.

Therefore, the present invention aims to solve the above problems,
An object of the present invention is to provide an ignition timing control device for an internal combustion engine that suppresses the occurrence of knocking without having to increase the size of an ignition system device or having adverse effects such as sacrificing output.

Structure of the Invention [Means for Solving the Problem] In order to achieve the above object, the present invention has the following structure as a means for solving the problem. That is, as illustrated in FIG. 1, in the ignition time control device for an internal combustion engine that controls the ignition time of the internal combustion engine M1 according to the rotational speed and the load, there is a load change that calculates the amount of change in the load of the internal combustion engine M1. an amount calculation means M2, a sudden change determination means M3 for determining a sudden change period in which the load suddenly changed based on the amount of change in the load, and a correction for retarding the ignition timing by a predetermined period after the sudden change period has elapsed. Means M
This is a configuration of an ignition time control device for an internal combustion engine characterized by comprising the following.

[Operation] In the ignition time control device for an internal combustion engine having the above configuration, the load change amount calculation means M2 calculates the amount of change in the load of the internal combustion engine M1, and the sudden change determination means M3 calculates the amount of change in the load of the internal combustion engine M1. The correction means M4 determines the sudden change period based on the amount of negative change, and retards the ignition timing for a predetermined period after the sudden change period determined by the sudden change determination means M3 has elapsed, so that it is possible to avoid an increase in the size of the device. , the occurrence of knocking can be suppressed without adverse effects such as sacrificing output.

[Example code] Embodiments of the present invention will be described in detail below based on the drawings.

FIG. 2 is a schematic diagram of an internal combustion engine that performs ignition time control, which is an embodiment of the present invention. This internal combustion engine has an intake pipe 4 and an exhaust pipe 6 that communicate with a combustion chamber 2 in an internal combustion engine main body 1, and a fuel injection valve 8 that injects fuel into the intake air of the intake pipe 4 and is provided in the combustion chamber 2. The spark plug 10 is provided.

Further, the intake pipe 4 is provided with a throttle valve 14 and a surge tank 16, which are sequentially opened and closed in response to an accelerator pedal (not shown) from the intake side toward the combustion chamber 2. Further, a throttle opening sensor 20 that detects the opening degree of the throttle valve 14 in conjunction with the throttle valve 14, and an intake pressure detection sensor 22 that is disposed in the surge tank 16 and detects the intake pressure P■ as a load are arranged. It is set up.

On the other hand, there are provided an igniter 28 that outputs the high voltage necessary for igniting the spark plug 10, and a distributor 30 that works in conjunction with a crankshaft (not shown) and distributes the high voltage generated by the igniter 28 throughout the spark plug 10. Further, the distributor shaft 32, which is installed inside the distributor 30 and outputs a rotational angular position signal every time it rotates a certain amount, for example, outputs a rotational angular position signal every time the distributor shaft 32 rotates 30 degrees, which rotates once for every two revolutions of the crankshaft. A rotation angle sensor 34 that outputs an output, and a reference position sensor that is installed in the distributor 30 and outputs a reference position signal at a reference position during one rotation, for example, outputs a pulse signal when the distributor shaft 32 rotates 180 degrees. It is equipped with 36.

The fuel check valve 8, the spark plug 10, the throttle opening sensor 20, the intake pressure detection sensor 22, the rotation angle sensor 34
, and the reference position sensor 36 are each connected to an electronic control circuit 50. This electronic control circuit 50! j: An input/output circuit configured with a well-known CPU 52, ROM 54, and RAM 56 as the core of a logic operation circuit, and which performs external and human output, here, an input circuit 5 and an output circuit 60 are interconnected via a common bus 62. It is connected to the.

The CPU 52 inputs signals from the throttle opening sensor 20, intake pressure detection sensor 22, rotation angle sensor 34, and reference position sensor 36 via the input circuit 5B. On the other hand, based on these signals and the data in the ROM 54 and RAM 56, the CPU 52 outputs a drive signal to the fuel injection valve 8 and the igniter 28 via the output circuit 60, thereby controlling the internal combustion engine main body 1.

Next, the processing performed in the electronic control circuit 50 described above will be explained using flowchart I in FIG.

When a key switch (not shown) is turned on, the ignition timing control system executes the control routine shown in FIG. 3 along with other control routines. The retard control routine shown in FIG. 3 is interrupted after ignition.

First, the rotational speed NE detected by the rotation angle sensor 34 and the intake pressure Pn+ as a load detected from the intake pressure detection sensor 22 are read (step 100). Next, based on the engine speed NE and intake pressure Pm, an ignition advance value θBSE is calculated from a map of ignition timing characteristics shown in FIG. 4 and stored in advance in the ROM 54 (step 110). In addition, in this embodiment, the rotational speed NE and the intake pressure P
Although the ignition advance value θBSE was calculated from m, the rotation speed NE
The ignition advance value θBSE may be calculated using a map similar to the map shown in FIG. 4, based on the ratio (Q/N) between the rotational speed NE and the intake air amount Q.

Subsequently, the amount of change ΔPu+i in the intake pressure P m is calculated (step 120). By repeatedly executing this control routine, the change in the intake pressure Pn+ is determined from the difference between the intake pressure Pm1-1 detected in the current execution and the previous execution. Amount△Pmi
(=Pmi-Pmi-1) is calculated.

As shown in FIG. 5(B), when the accelerator pedal (not shown) is operated, the throttle opening changes and the intake pressure P
+n changes accordingly. That is, when the load increases as the vehicle attempts to accelerate, the intake pressure Pm increases depending on the load.
changes. When the accelerator pedal is suddenly depressed, the intake pressure Pa increases as shown by the solid line in Fig. 5(B).
The amount of change ΔP+ni in n becomes a large value. Furthermore, if the operating speed of the accelerator pedal is slow, the amount of change ΔP in the intake pressure P m is shown by the two-dot chain line in FIG.
m i becomes a small value. Note that the execution of the process in step 120 functions as load change amount calculation means M2.

Next, the amount of change ΔPmi in the calculated intake pressure Pm is set to a predetermined value (+'1la (for example, 30 m...H
g) Determine whether it is greater than (step 130).

If the amount of change △P■i in the intake pressure P... is larger than a predetermined value (lua), the acceleration counter CACC is increased by 1 (step 140). That is, the amount of change △P in the intake pressure P...
When the state in which 1 old is greater than the predetermined value a continues, the acceleration counter CACC counts the number of consecutive times.

On the other hand, by repeatedly executing this control routine, the intake pressure P
When the amount of change ΔPmi becomes less than a predetermined value a, it is determined whether the transient retard amount θkNK calculated from the process described later exceeds 0 (step 150). This transient retard amount θKNK is reset to 0 in advance by an initial routine (not shown) at startup, and before the processing described later is executed, the transient retard amount θKNk is 0 or less, and in this case, , it is determined whether the acceleration counter CACC exceeds a predetermined value b (for example, a value of about 2 to 4) (step 160). That is, as shown by the solid line in FIG. 5(B), when the accelerator pedal is suddenly depressed and the amount of change ΔPmi in the intake pressure Pm is greater than the predetermined value a, it continues for a predetermined number of times (flm b). This period is determined to be a period of rapid change.

When the speed of the vehicle changes from low speed to medium speed as shown by the two-dot chain line in Figure 5 (1B),
As shown by the dashed line in B), when the speed is small, as is the case when the speed changes from medium to high, the amount of change △P+ni of the intake pressure Pm is smaller than the predetermined value a, so it is not a sudden change period. It is determined that In addition, if the pressure in the intake pipe 4 changes for some reason and the change amount ΔP+ni of the intake-same pressure P111 is greater than the predetermined value a, but it does not continue for more than the predetermined value a, the sudden change occurs. It is determined that it is not a period. Note that step 130.
The execution of the processes 140 and 160 serves as the sudden change determining means M3.

Next, if the acceleration counter C8CC exceeds the predetermined value, the transient retard amount θkNk is calculated (step 170).
. That is, if the amount of change ΔP m i in the intake pressure Pm is a predetermined value (f
The transient retardation amount θKNk is calculated after a sudden change period has elapsed after the state of being larger than ia continues for a predetermined value or more times and the change amount ΔP+ni+1 of the intake pressure Pl'11 becomes smaller than the predetermined value a. . This transient retardation amount θkNk is
It is calculated based on the acceleration counter CACC from a map shown in FIG. 6(A) and stored in advance in the ROM 54. When the acceleration counter CACC is large, the transient retardation amount θkNk is also calculated as a large value. This is the acceleration counter CA
When CC is large, the amount of change in intake pressure P... ΔP +n
A state in which the quotient 5 is greater than the predetermined value a for a long time,
The transient retardation amount θkNK is also a large value in proportion to the length of the sudden change.

Note that this calculation is not limited to the map, but also the acceleration counter CAC.
It may be calculated by a calculation formula using C as a variable, and instead of the acceleration counter CACC, the intake pressure Pm
Based on this, the transient retard amount θkNk may be calculated using a map shown in FIG. 6(B). In this case, the larger the intake pressure P... is, the larger the transient retardation amount θkNk is. This is because the larger the intake pressure P m is, the more likely knocking is to occur. Furthermore, the transient retard amount θKNk may be calculated from the map t shown in FIG. 6(C) based on the rotational speed NE. In this case, the lower the rotational speed NE, the larger the value of the transient retard amount θKNk. This means that when the intake pressure Pm is changing, the rotational speed NE is still almost unchanged, but the lower the rotational speed NE is, the more the ignition advance value θB
This is because SE is set to the advanced side and is close to the knocking generation limit, so the lower the rotational speed NE is, the more likely knocking is to occur.

After calculating this transient retard amount θkNk, next, this transient retard amount θkNk is subtracted from the ignition advance value θBSE calculated by the process of step 110, and the ignition advance value θ
The data is set in the BSE and stored in a predetermined location in the RAM 56 (step 180). That is, the ignition advance value θBSE is corrected according to the transient retard amount θkNk. Next, the acceleration counter CACC is reset to 0 (step 190).

The ignition advance value θBSE calculated in this way is read out by an interrupt routine executed at a predetermined crank angle position, and is read out by the interrupt routine executed at a predetermined crank angle position, and the ignition advance value θBSE is read out by the interrupt routine executed at a predetermined crank angle position.
An ignition signal representing the ignition timing is determined according to the ignition advance value θBSE, and ignition is performed by the ignition plug 10. That is, as shown in FIG. 5(A), the intake pressure Pan
When the amount of change ΔP■1 becomes less than the predetermined value a, the ignition advance value θBSE is retarded by the transient retardation amount θkNk.

On the other hand, after repeatedly executing this control routine and after the sudden change period has elapsed, the transient retard amount θkN is determined by the process of step 170.
K has already been calculated, and if the transient retard amount θkNk exceeds 0 as a result of processing in the step 150 (step 150), a preset attenuation constant K is subtracted from the transient retard amount θkNk. Then, the transient retardation amount is set to 8 KNK again (step 200). Next, by repeatedly executing this control routine, this new transient retard amount θkNK is subtracted from the ignition advance value θBSE calculated in the process of step 110, and a new ignition advance value θB
SEt is set (step 180). That is, by repeatedly executing the processes of steps 100 to 150, 200, 180, and 190, the transient retard amount θkNk is gradually attenuated with the passage of time, as shown in FIG. 5(A).

On the other hand, as mentioned above, when the transient retardation amount θKNk gradually attenuates over time and becomes 0 or less (step 1
50) At this point, the acceleration counter CACC has already been reset to 0 by the processing in step 190, so the processing from step 190 onwards is performed without executing the processing in steps 170 and 180. is executed to temporarily end this control routine. That is, during a predetermined period until the transient retard amount θkNk becomes 0, the ignition advance value θBSE is corrected according to the transient retard amount θKNK. On the other hand, as shown in Figure 5 (C), the vehicle speed is
-' It begins to rise after a change in m. Note that the execution of the processes in steps 150, 160 to 200 is performed by the correction means M.
4 and C work.

As described above, the ignition time control device for an internal combustion engine according to the present embodiment calculates the amount of change ΔPmi in the intake pressure P111 as a load, and controls the amount of change ΔP + n i hl to exceed a predetermined value a consecutively for a predetermined number of times. After the subsequent sudden change period has elapsed, the ignition advance value θBSE is maintained for a predetermined period according to the transient retardation amount θKNk.
Corrects the delay angle.

Therefore, according to the ignition timing control device for an internal combustion engine of this embodiment, the ignition timing is retarded for a predetermined period after the sudden change period has elapsed. Therefore, during the period when the intake pressure P There is no need to increase the size of the ignition advance value θ at the beginning of acceleration when the accelerator pedal is depressed.
There is no adverse effect such as sacrificing the output by retarding the BSE. Furthermore, knocking that occurs during a period T after the intake pressure P111 suddenly changes as shown in FIG. 8 is suppressed by retarding the ignition advance value θBSE.

In this example, the intake pressure Pm was used as the load, but the ratio of the rotational speed NE to the intake air amount Q (Q/N
It is also possible to use E) and calculate the transient retard amount based on this Q/NE.

Although the embodiments of the present invention have been described above, the present invention is not equally limited to these embodiments, and it goes without saying that the present invention can be implemented in various forms without departing from the gist of the present invention.

Effects of the Invention As described in detail above, the ignition time control device for an internal combustion engine of the present invention retards the ignition timing for a predetermined period even after the sudden change period has elapsed, thereby reducing the size of the ignition system device. To achieve the effect of suppressing the occurrence of knocking after a sudden change in load without adversely affecting output such as sacrificing output.

[Brief explanation of the drawing]

FIG. 1 is a block diagram illustrating the basic configuration of the present invention;
FIG. 2 is a schematic configuration diagram of an ignition time control device for an internal combustion engine as an embodiment of the present invention, FIG. 3 is a flowchart showing an example of a retard control routine performed in the electronic control circuit of this embodiment, and FIG. The figure is a graph showing a map of the ignition timing characteristics of this embodiment, Figure 5 is a time chart explaining the ignition timing control of this embodiment, and Figure 6 is a map for calculating the amount of transient retardation of this embodiment. , FIG. 7 is a graph showing the conventional relationship between intake pressure and air-fuel ratio, and FIG. 8 is a graph showing the relationship between intake pressure and air-fuel ratio. Ml...Internal combustion engine M2...Negative change amount calculation means M3...Sudden change determination means M4...Correction means 1...
・Internal combustion engine main body 10...Spark plug 20-...Throttle opening sensor 22...Intake pressure detection sensor 50...Electronic control circuit representative Patent attorney Tsutomu Sadachi (and 2 others) Figure 3 Retard angle control Routine NE, Pm reading Calculation of θBSE Calculation of ΔPmi ΔPmi>aYES? Figure 4 'CA'

Claims (1)

[Scope of Claims] An ignition timing control device for an internal combustion engine that controls ignition timing of the internal combustion engine according to rotation speed and load, comprising: load change amount calculation means for calculating an amount of change in the load of the internal combustion engine; A sudden change determination means for determining a sudden change period in which the load suddenly changes based on the amount of change in the load, and a correction means for retarding the ignition timing for a predetermined period after the sudden change period has elapsed. Characteristics of the ignition timing control device for internal combustion engines.