JPH0650100B2 - Ignition timing control method for internal combustion engine - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to an ignition timing control method for an internal combustion engine, in which the ignition timing is learned and controlled according to whether knock has occurred.

[Prior art]

In recent years, as disclosed in Japanese Patent Laid-Open No. 58-217775, the maximum advancement that can suppress knocking within an allowable range so that the internal combustion engine can always be operated at the maximum torque under any operating condition. In order to realize the ignition timing control at the corner, there is provided an ignition timing control method for an internal combustion engine that learns an ignition timing correction value depending on whether knock occurs. However, in the above-mentioned prior art example, one ignition timing correction value covers all the regions, and there is a problem that the control accuracy is poor. In order to deal with this, as shown in Japanese Patent Laid-Open No. 58-107875, the ignition timing correction value is set for each operating region and learned for each operating region.

[Problems to be Solved by the Invention]

However, since each ignition timing correction value for each operating region is learned, learning is performed for the entire point angle timing control, and it takes a considerable time to obtain the optimum ignition timing value in each region, During this time, there is a problem that the occurrence rate of knocking increases and the driving feeling is bad. The present invention has been made in view of the above circumstances, and an internal combustion engine capable of converging the ignition timing of each region to the optimum ignition timing at an early stage to reduce the occurrence rate of knocking and improve the driving feeling. An object is to provide an ignition timing control method.

[Means for Solving the Problems]

In order to achieve the above object, an internal combustion engine ignition timing control method according to the present invention sets a basic ignition timing based on an engine load and an engine speed, and corrects the ignition timing by knocking detection using the engine load and the engine speed as parameters. In the ignition timing control method for an internal combustion engine, wherein the ignition timing correction value stored in the value map is learned, and the basic ignition timing is corrected by the ignition timing correction value to set the ignition timing. In the procedure for determining whether the learning condition is satisfied by reaching a predetermined number of corrections with, and when the learning condition is satisfied, the ignition timing correction value of the corresponding region is averaged including the ignition timing correction value of the peripheral region,
The procedure of updating the ignition timing correction values of all the regions of the ignition timing correction value map with this average value, and after updating the ignition timing correction values of all the regions, determine the ignition timing correction value of each region depending on the presence or absence of knocking. And a procedure for learning.

[Action]

In the present invention, when the predetermined number of corrections is reached in the same region of the ignition timing correction value map and the learning condition is satisfied, the ignition timing correction value of the corresponding region is averaged including the ignition timing correction value of the peripheral region, The ignition timing correction values for all the regions of the ignition timing correction value map are updated with this average value, and then the ignition timing correction values for each region are learned.

【Example】

An embodiment of the present invention will be specifically described below with reference to the drawings. In FIG. 1, reference numeral 1 is a sensor that detects an intake pipe pressure (or an intake air amount) as an example of an engine load, and the sensor output is input to an A / D converter 3 via a buffer 2 and a digital signal. It is converted into a signal and input to the microprocessor 18. Reference numeral 4 is a sensor such as a crank angle sensor for detecting the engine speed,
The sensor output is input to the interrupt processing circuit 6 via the buffer 5. Then, the sensor output is input to the microprocessor 18. On the other hand, when knocking occurs, a knock signal is output from the knock sensor 7 and input to the microprocessor 18. The filter 8 cuts noise due to steady vibration such as vibration of the valve train during engine drive from the knock signal.・ Turn off. Further, since the knock signal level changes and the noise level also changes due to the difference in engine speed when knocking occurs, the output of the filter 8 is divided, one is input to the amplifier 9, and the other is rectified / integrated. The averaging is performed through the circuit 10, the level is adjusted by the amplifier 11 to adjust the level, and the level is subtracted by the comparator 12 to determine and extract the knock signal. The internal structure of the microprocessor 18 is, as is well known, an input port 13, an output port 14, a CPU 15, and a RAM 16 and a ROM 1 which partially constitute a non-volatile memory.
7 is connected by a bus line, and the matched sensor signal received by the microprocessor 18 is input to the input port 13 and the output port 14
Outputs a control signal to the output circuit 19, and the output circuit 19 outputs a drive signal to the ignition device 21. The ROM 17 stores a control program and fixed data for various controls such as a data map and a data table, and the RAM 16 outputs the output signals of the sensors after data processing and the CPU 15 calculates the data. The processed data is stored, and a non-volatile portion of the RAM 16 has an overall correction end flag FTCMP, which will be described later.
A correction number holding map, an ignition timing correction value map, and an acceleration correction map are stored. The CPU 15 calculates the ignition timing according to the control program stored in the ROM 17, outputs a control signal to the output circuit 19, and outputs the ignition timing correction value SPK.
Learn prt. Hereinafter, the ignition timing control and learning control procedures will be described. The ignition timing is set in the interrupt routine of FIG. 5 which is executed every predetermined time. In this ignition timing setting routine,
First, in step S61, the engine speed and the intake pipe pressure are obtained based on the output signals from the engine speed sensor 4 and the intake pipe pressure sensor 1, respectively, and in step S62, the acceleration determination value table is referred to based on the engine speed. The acceleration judgment value ΔBST (mmHG) is set. As shown in FIG. 3A, this acceleration determination value table stores the acceleration determination value at each address using the engine speed as a parameter, and is a ROM as a data table.
It is stored in 17. Next, in step S63, the acceleration determination value ΔBS
T is compared with the intake pipe pressure change amount BST _R per set time, and if BST _R > ΔBST, it is determined that acceleration and the basic ignition timing map, based on the intake pipe pressure and engine speed, in step S64. The basic ignition timing SPKtot and the ignition timing correction value SPKprt are set by referring to the ignition timing correction amount map, and the acceleration correction amount (retard) SPKacc is set by referring to the acceleration correction map based on the engine speed. Based on this, the ignition timing SPKreal is set and the routine exits. SPKreal ← SPKtot ± SPKprt −SPKacc On the other hand, if BST ≦ ΔBST in step S63, it is determined that the steady state is reached, and the process proceeds to step S65, in which the basic ignition timing map and ignition are respectively calculated based on the intake pipe pressure and the engine speed. Referring to the timing correction value map, the basic ignition timing SPKtot and the ignition timing correction value SPK
Set prt, set ignition timing SPKreal based on the following equation, and exit the routine. SPKreal ← SPKtot ± SPKprt As shown in Fig. 2 (a), the above basic ignition timing map shows that the knock limit of knocking can be suppressed within an allowable range when low octane fuel such as regular gasoline is used. The ignition timing with the maximum advance angle is obtained in advance by experiments or the like using the engine speed and the suction pipe pressure as parameters and stored in the ROM 17. The ignition timing correction value map is stored in the non-volatile memory portion of the RAM 16 and corresponds to the area A of the basic ignition timing map shown in FIG. 2 (a) and is shown in FIG. 2 (b).
As shown in, the ignition timing correction value SP for each region specified with the engine speed and the suction pipe pressure as parameters.
Kprt is stored and learned for each operation region by the learning procedure described later, and the value of the ignition timing correction value SPKprt is updated. Further, the acceleration correction map is also stored in the non-volatile memory portion of the RAM 16, and as shown in FIG. 3B, the acceleration correction amount SPKacc is stored for each region specified by the engine speed as a parameter. The value is learned and updated by a learning procedure described later. In the present embodiment, the suction pipe pressure change is used for the acceleration determination, but it may be any as long as the acceleration can be determined, and for example, the throttle opening change speed or the like may be used. Next, a procedure for learning the ignition timing correction value SPKprt and the acceleration correction amount SPKacc will be described with reference to FIG. FIG. 6 is a main routine of the learning procedure, which is executed every ignition. First, in step S71, the acceleration determination value ΔB set by referring to the acceleration determination value table based on the engine speed.
ST is compared with the suction pipe pressure change amount BST _R per set time. If BST _R > ΔBST, it is determined that the acceleration has occurred, the process proceeds to step S72, and the acceleration correction amount subroutine SPKacc is called by calling the acceleration correction execution subroutine.
To finish the routine. On the other hand, in step S71, if BST _R ≤ ΔBST, that is, if the steady state, the process proceeds to step S73, where R
The value of the overall correction end flag FTCMP is read from a predetermined address of the non-volatile memory portion of the AM 16 and it is determined whether or not the overall correction is completed. If FTCMP = 0, that is, if the overall correction is not completed, the process proceeds to step S74 to call the overall correction execution subroutine to learn the entire correction of the ignition timing correction value SPKprt, and the routine is ended. In addition, the whole correction end flag FTCM
The initial set value of P is 0. In step S73, when FTCMP = 1, that is, when the entire correction is completed, step S73
75, the partial correction execution subroutine is called to learn the ignition timing correction value SPKprt for each region specified by the engine speed and the intake pipe pressure, and step S76
Then, the ignition timing correction value SPKpr learned by this partial correction
It is judged whether or not t exceeds the limit value, that is, whether large knocking occurs or correction of advance angle or retard angle in the same direction continues, and whether it greatly deviates from the optimum ignition timing. If not, the routine is ended, and if it is exceeded, it is determined that the ignition timing is largely deviated from the optimum ignition timing, the process proceeds to step S77, and the overall correction end flag FTCMP is cleared to shift to the overall correction when the next routine is executed. (0 → FTCMP), and the routine ends. Steps S72 and S7 of the learning control main routine described above
4, the acceleration correction execution subroutine, the whole correction execution subroutine, and the partial correction execution subroutine in S75 are shown in FIGS. 7, 8 and 9, respectively. In the acceleration correction execution subroutine of FIG. 7, step S8
Whether or not knocking has occurred is determined in 1, and if knocking has occurred, the process proceeds to step S82, and if no knocking has occurred, the process branches to step S85. First, when the case where knocking occurs is explained,
In step S82, the knock intensity KNSTRG is obtained based on the knock sensor output, and the process proceeds to step S83 to set the retard amount RETacc based on the knock intensity KNSTRG.
This retard amount RETacc is set to a larger value as the knock intensity KNSTRG increases as shown in FIG. 3 (c), and the functional expression RETacc = f (KNSTR
G) or knock strength KNSTRG as a parameter. Then, the acceleration correction amount SPKacc is read from the corresponding address of the acceleration correction map specified by the engine speed and the retard angle amount RETacc is added,
The acceleration correction amount SPKacc is reset and the process proceeds to step S89, the acceleration correction amount SPKacc stored in the corresponding address of the acceleration correction map is updated with this value, and the routine exits. On the other hand, if knocking does not occur in step S81, it is determined in step S85 whether knocking has occurred the set number of times in the operating region specified by the engine speed, and if knocking has not occurred the set number of times, The routine is exited, and if knocking occurs for the set number of times, the process proceeds to step S86. In step S86,
The acceleration correction value SPKacc is read from the corresponding address of the acceleration correction map specified by the engine speed, and the preset retard angle amount ADVacc is subtracted to obtain the acceleration correction amount SPKac.
c is reset, and the routine proceeds to step S87, where it is judged if this acceleration correction value SPKacc is a negative value. If SPKacc ≧ 0, it is the retard value, so jump to step 89 and reset the acceleration correction amount SPKacc. Acceleration correction amount SP stored at the corresponding address in the acceleration correction map at
Update Kacc and exit the routine. If SPKacc <0, it means that the reset acceleration correction amount SPKacc has become the advance value. To limit this, the process proceeds to step S88, where the acceleration correction amount SPKacc is set to 0,
In step S89, the acceleration correction amount SPKacc stored in the corresponding address of the acceleration correction map is updated, and the routine exits. Further, in the overall correction execution subroutine shown in FIG. 8, it is determined in step S91 whether the engine speed and the intake pipe pressure at present are within the region A of the basic ignition timing map (see FIG. 2 (a)). That is, it is determined whether or not it is within the region of the ignition timing correction value map. If it is not within the region, the routine is exited. If it is within the region, the routine proceeds to step S92.
In step S92, the ignition timing correction value map area specified by the engine speed and the intake pipe pressure (one of the address areas divided into a grid, for example, the grid point (5) in FIG. 2B is specified). Is read from the corresponding region (address) of the correction number holding map based on the engine speed and the suction pipe pressure, and it is determined whether the correction number has reached the set number. The correction number holding map is stored in the non-volatile memory part of the RAM 16, and the correction number is stored for each region specified by the engine speed and the intake pipe pressure as parameters, as in the ignition timing correction value map. Ignition timing correction value SPKpr of address with timing correction value map
When t is updated by learning, the number of corrections stored in the address of the corresponding correction number holding map is incremented. If the number of corrections has not reached the set number in step S92, the routine is exited, and if it has reached the set number, the process proceeds to step S93. Then, the corresponding address of the ignition timing correction value map, for example, the ignition timing correction value SPKprt of the grid point (5) in FIG. 2 (b).
5 is read out, and the ignition timing correction values SPKprt 1 to 4 stored in the addresses (1) to (4) and (6) to (9) of the designated area (8 areas in the present embodiment) around it are read. 6
9 to 9 are read out, and the average value (weighted average) Ave is calculated by the following equation. Ave ← {(SPKprt1 + SPKprt2 + SPKprt3 + SPKprt4 + SPKprt6 + SPKprt7 + SPKprt8 + SPKprt9 / 8 + SPKprt5} / 2 Then, at step S94, all the values of the ignition timing correction value map, ie, the entire area of the ignition timing correction value map, ie, all the ignition timing correction values SP, all areas of the ignition timing correction value map are corrected. Then, the correction counts of all the addresses in the correction count holding map are reset, and the process proceeds to step S95 to set the whole correction end flag FTCMP to shift to the partial correction when the whole correction is completed (F
TCMP ← 1), exit the routine. In this way, the ignition timing correction value SPKprt of the area where the number of corrections reaches the set number of times in the entire control area is calculated, and this is used as the ignition timing correction value of the entire control area to predict the overall correction. , To set. In order to improve the accuracy of the ignition timing correction value in the peripheral area, the ignition timing correction value in the area where the number of corrections reaches the set number may be the center of the calculation. When the ignition timing correction value SPKprt exceeds the limit value and greatly deviates from the optimum ignition timing after the partial correction is executed in the main routine described above, the overall correction end flag FTCMP is cleared (see step S77), and the entire correction is immediately performed. Then, by the above-mentioned overall correction execution subroutine, an ignition timing correction value having a high correction probability (the number of corrections) is calculated including the ignition timing correction value in the peripheral region (averaging process) to obtain a proper ignition timing correction value, Since this is applied to the correction value of the entire control region and the partial correction described later is executed, the ignition timing of each region can be converged to the optimum ignition timing at an early stage. In the partial correction execution subroutine of FIG. 9, the engine speed and the intake pipe pressure are calculated in step S101, and the current engine speed and intake pipe pressure are within the control region of the ignition timing correction value map in step S102. If it is not in the area, the routine is exited. If it is in the area, the process proceeds to step S103. In step S103, the ignition timing correction value SPKprt and the correction number are read from the corresponding addresses of the ignition timing correction value map and the correction number holding map, which are specified based on the engine speed and the suction pipe pressure, respectively, and the step S10 is performed.
In step 4, the correction coefficient LN and the knock generation interval determination value (advance determination time) ADJ are set by referring to the correction coefficient table and the knock generation interval determination value table based on the number of corrections, and the process proceeds to step S105. The correction coefficient table and the knock occurrence interval determination value table are stored in the ROM 17 as a data table, and as shown in FIG. 4A, the correction coefficient table has a value in which the correction coefficient LN increases as the number of corrections decreases. Further, the knock occurrence interval determination value table stores a knock occurrence interval determination value (advance angle determination time) ADJ as a short value as the number of corrections decreases. In step S105, it is determined whether or not knocking has occurred, and if knocking has occurred, the process proceeds to step S106 to perform retard control. In step S106, the knock intensity and the knock occurrence interval are calculated, and the retard amount KNK is set by referring to the map based on the knock intensity and the knock occurrence interval. The map above is
It is stored in the ROM 17 as a data map, and the larger the knock intensity and the shorter the knock occurrence interval, the larger the retard amount KNK is stored. Then, in step S107, the retard amount KNK is set to the step S1.
The actual retard amount RE is multiplied by the correction coefficient LN set in 04.
Treal is calculated (KNK · LN → RETreal), the process proceeds to step S108, and the actual retard angle amount RETre is calculated from the ignition timing correction value SPKprt read in step S103.
By subtracting al, the ignition timing correction value SPKprt stored in the corresponding address of the ignition timing correction value map specified by the engine speed and the intake pipe pressure is updated. On the other hand, in the above step S105, if there is no knocking, the process proceeds to step S109 to execute the advance angle control, and it is determined whether there is knocking within the advance angle determining time ADJ. If there is knocking, the routine is executed. If there is no knocking and there is no knocking, the process proceeds to step S110. In step S110, the advance amount ADV set in advance is added to the ignition timing correction value SPKprt read in step S103 to calculate the current ignition timing correction value SPKprt, and in step S111, the ignition timing correction value calculated this time. SPKpr
t and the ignition timing MB at which the maximum torque obtained based on the current engine speed and engine load can be obtained.
A comparison is made with a limit value (MBT-SPKtot) obtained by subtracting the current basic ignition timing SPKtot from T, and if SPKprt ≤ MBT-SPKtot, the routine jumps to step S113, and the ignition timing correction of this time calculated in step S110. Value SPKprt
Then, the ignition timing correction value SPKprt stored in the corresponding address of the ignition timing correction value map specified by the engine speed and the intake pipe pressure is updated, and the routine is exited. If SPKprt> MBT-SPKtot in step S111, the angle is excessively advanced beyond MBT, so the process proceeds to step S112, and the limit value (MBT-SPKto
t) as the ignition timing correction value SPKprt, and step S11
In step 3, the ignition timing correction value SPKprt stored in the corresponding address of the ignition timing correction value map is updated, and the routine exits. Although the intake pipe pressure is used as the engine load in the present embodiment, it may be any value that represents the engine load.
It is not limited to this. Further, in the present embodiment, for the overall correction, when a predetermined number of corrections is satisfied for the same operating region (for an operating region that first reaches the predetermined number of corrections), the ignition timing correction value at that time is calculated to perform ignition. The ignition timing correction value SPKprt for all areas (addresses) of the timing correction value map is updated, but the learning condition is not the number of corrections but the correction to the retard value and the correction to the advance value. The number of times of changing directions may be changed.

【The invention's effect】

As described above, according to the present invention, when the ignition timing is largely deviated from the optimum ignition timing, the ignition timing correction value in the region having a high correction probability is calculated by including the ignition timing correction value in the peripheral region and a proper ignition is performed. By obtaining the timing correction value, applying it as the ignition timing correction value for the entire control range, and then executing the partial correction, the ignition timing of each region can be converged to the optimum ignition timing at an early stage. Further, it is possible to obtain an excellent effect such that the knocking occurrence rate is reduced and the driving feeling is improved.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram of a control system showing an embodiment of the present invention, FIG. 2 (a) is an explanatory diagram of a basic ignition timing map, and FIG. 2 (b) is an explanatory diagram of an ignition timing correction value map, 3 (a) is an explanatory diagram of an acceleration determination value map, FIG. 3 (b) is an explanatory diagram of an acceleration correction map, and FIG. 3 (c) is an explanatory diagram showing the relationship between knock intensity and retard amount. FIG. 4 (a) is an explanatory diagram of a correction coefficient table, FIG. 4 (b) is an explanatory diagram of a knock occurrence interval determination value table, FIG. 5 is a flowchart showing an ignition timing setting procedure, and FIG. 6 is an ignition timing correction. FIG. 7 is a flowchart showing a main routine for learning the value and acceleration correction amount, FIG. 7 is a flowchart showing a subroutine for learning the acceleration correction amount, FIG. 8 is a flowchart showing a whole correction execution subroutine for learning the ignition timing correction value, and FIG. Time correction value learning partial correction execution support It is a flowchart illustrating a routine. 1 ... Suction pipe pressure sensor, 4 ... Engine speed sensor, 7 ... Knock sensor, 18 ... Microprocessor, 21 ... Ignition device, SPKtot ... Basic ignition timing, SPKprt ... Ignition timing correction amount, SPKreal ...... Ignition timing,

Claims (1)

[Claims] 1. A basic ignition timing is set based on an engine load and an engine speed, and an ignition timing correction value stored in an ignition timing correction value map is learned by knocking detection using the engine load and the engine speed as parameters. In an ignition timing control method for an internal combustion engine in which the basic ignition timing is corrected by an ignition timing correction value to set the ignition timing, it is determined whether a predetermined number of corrections has been reached in the same region in the ignition timing correction value map and a learning condition is satisfied. When the learning condition is satisfied, the ignition timing correction value of the corresponding area is averaged including the ignition timing correction value of the peripheral area, and the ignition timing correction of all the areas of the ignition timing correction value map is performed with this average value. After updating the value and the ignition timing correction value for all the regions, the ignition timing correction value for each region is learned according to the presence or absence of knocking. Ignition timing control method for an internal combustion engine, characterized in that it comprises a sequence.