JPH01294966A - Ignition timing control device - Google Patents

Abstract

PURPOSE:To contrive a stable control by invalidating the total unit correction, existing till that time, and performing the new total unit correction when a partial correction amount exceeds a predetermined reference value in accordance with an engine speed, in the case of the ignition timing characteristics performing its total unit correction and partial correction. CONSTITUTION:An ignition timing arithmetic device 20, being based on an engine speed calculated in an arithmetic part 22 and an intake air amount calculated in an arithmetic part 23, calculates a basic fuel injection width in an arithmetic part 24. While an arithmetic part 25 calculates the basic ignition timing being based on the engine speed and the basic fuel injection width. Further an arithmetic part 26 calculates a total unit correction coefficient being based on a knocking signal from a knocking decision circuit 12. While an arithmetic part 27, being based on the knocking signal, calculates a partial correction value in every lattice divided by the engine speed and the basic fuel injection width. And when the partial correction value exceeds a predetermined reference value in accordance with the engine speed, and arithmetic part 28 decides arithmetic execution of the new total unit correction value.

Description

[Detailed description of the invention] [Field of use in M industry]

The present invention detects intake air pressure and engine speed and sets the ignition timing value at that time, and when knocking is detected,
The present invention relates to an ignition timing control device for an internal combustion engine that corrects the above set ignition timing value.

[Conventional technology]

Conventionally, electronic ignition timing control devices have been devised to control the ignition timing at the maximum advance angle that can suppress knocking within an allowable range.
As shown in Publication No. 5, a map with intake air pressure and engine speed as parameters is provided in the ROM, and basic ignition timing values that serve as a model are written therein.
If knocking occurs during operation control using that value, a correction value is calculated and the ignition timing value is partially corrected. However, with this method, if the basic ignition timing value used as a model deviates significantly due to the quality of the gasoline actually used (octane number), etc., it is not possible to correct it by shifting it as a whole; Frequency of correction is high,
It takes time to learn, which is not good for ignition timing control.
Therefore, as shown in Japanese Patent Application Laid-Open No. 58-57072, a method has been proposed in which multiple maps are prepared in the ROM and used selectively according to the octane number of the gasoline. It cannot respond to changes in operating conditions such as different locations. Therefore, as shown in Japanese Patent Application No. 59-280564, for example, variations in fuel octane number and individual engines,
Alternatively, in order to respond to changes in the limit of knocking caused by changes over time, the ROM is equipped with two high and low ignition timing maps that parameterize engine speed N and basic fuel injection (Tl). An overall correction is made to determine where the value of the ignition timing is between the two maps, and furthermore, each ignition timing value is The ignition timing value is partially corrected, and if this partial correction value becomes larger than a predetermined value, it is determined that the overall correction value is inappropriate, and the previous overall correction including the partial correction is performed. is cleared and the entire correction is performed again.

[Problem to be solved by the invention]

However, in the above-mentioned prior art, in the low engine speed range, the amount of intake air is small, and it is affected by the temperature in the engine room and the cooling water temperature, and the change in intake air temperature is large.
Therefore, the change in the knock limit is larger than in the high rotation range, and knob king is more likely to occur when restarting or driving in traffic jams, so the partial correction value becomes large and the overall correction is performed again. Even though the increase in intake temperature after starting the engine is temporary, if the overall correction is performed, stable learning of the ignition timing becomes impossible. In addition, if the reference value for partial correction, which is used to determine whether to perform overall correction, is set to a large value in accordance with the change in the knock limit due to the rise in intake air temperature in the low rotation range, it will be possible to determine whether to perform overall correction in the medium or high rotation range. However, if there is a real change in the knock limit (gasoline octane number, etc.), it becomes difficult to learn quickly. The present invention has been made to solve the above-mentioned problems, and by changing the criterion for characteristic switching according to the engine speed, it is possible to prevent unnecessary switching of ignition timing characteristics due to the influence of intake air temperature, etc. The purpose is to make it possible to prevent it.

[Means to solve the problem]

In order to achieve the above object, the present invention detects intake air pressure (or intake air amount) and engine speed, sets the ignition timing value at that time, and corrects the ignition timing value when knocking is detected. In order to determine the overall correction coefficient for the area where ignition timing control is required, this is taken in and calculated at the start of control, and the result is applied to the entire ignition timing correction for the area where control is required.

[At the same time, in the next stage, each partial correction value of the map divided using intake air pressure (or intake air amount) and engine speed as parameters is learned and updated under predetermined conditions, and the above overall correction ignition timing is adjusted. In ignition timing learning control that is configured to apply correction to the value and return to the overall correction when the above partial correction value exceeds a preset reference value, the previous overall correction is invalidated and a new overall correction is performed. The reference value for determining whether to perform correction is set in accordance with the engine rotation speed. [For production]

Based on the above configuration, the size of the reference value for the partial correction that determines whether to perform the overall correction is set according to the size of the rotation speed. Temporary knock limit changes caused by such factors can be dealt with by only partial correction, and overall correction corresponding to conditions such as gasoline octane number is not affected.

【Example】

An embodiment of the present invention will be described below with reference to FIGS. 1 to 9. In FIG. 1, reference numeral 1 is a sensor that detects the suction pipe negative pressure (or intake air -tQ), and the sensor output is input to the A/D converter 3 via the buffer 2, where it is digitally converted. The output of the crank angle sensor 4, which detects the engine speed, is input to the interrupt processing circuit 6 via the buffer 5. On the other hand, when knocking occurs, a knock signal is generated from the knock sensor 7, noise caused by steady vibration such as vibration of the valve train is cut off by the buffer filter 8, and the output is divided into two parts, one of which is input to the amplifier 9. The other signal is averaged by the rectifier/integrator circuit 10, amplified by the amplifier 11 to adjust the level, and compared by the comparator 12 to determine and extract a knock signal. The outputs of these sensors 1 and 4 and the knock signal extracted by the comparator 12 are sent to the output port 1 via the input port 13.
4, the data is input to a microprocessor 18 composed of a CPU 15, a RAM 16, a ROM 17, and the like. And R
A control signal calculated according to the program of the OM 17 is output from the ignition timing control device 20 to the ignition device 21 via the output circuit 19. Here, the ROM 17 stores a map 17a which stores predetermined ignition timing values using intake air pressure (or intake air amount) and engine speed as parameters, as shown in FIGS. , 17b, and a map 17c for determining the overall correction execution using the engine speed N as a parameter as shown in FIG. A high-low ignition timing difference map 17d (the one shown in the figure is an example; in reality, it has 256 grids of 16 x 16) is provided. First ignition timing map 17a (hereinafter referred to as
The ignition timing value at the maximum permissible torque exerted by the internal combustion engine is written as the upper limit ignition timing value in the MBT map (hereinafter referred to as MBT map), and the second ignition timing map 17b (hereinafter referred to as
The basic map (referred to as MAPSTD) includes a knock limit ignition that provides the maximum advance angle that can suppress knocking within an acceptable range for the specified fuel used in the internal combustion engine, such as regular gasoline or low-octane gasoline. The timing value is written as the lower limit ignition timing value. Next, a second section showing a schematic functional configuration of the ignition timing calculation device 20 will be described.
In the figure, an engine speed calculating section 22 calculates the engine speed N based on the signal from the crank angle sensor 4, and an intake air amount calculating section 23 calculates the engine speed N based on the signal from the intake pipe pressure sensor 1 or the air flow meter 1'. Based on the calculated engine speed N and intake air amount Q, the basic fuel injection width calculation unit 24 calculates the basic fuel injection width (injection amount) Tp. Then, the ignition timing calculation unit 25 searches the ignition timing map 17b based on the engine speed N and the basic fuel injection width Tp (or the intake air pressure or the intake air amount Q), and determines the basic ignition timing MAP.
In addition to calculating the STD, the overall correction subroutine to be described later in the overall correction calculation unit 26 calculates the knock determination port F#.
The overall correction coefficient K is determined based on the knock signal from the I (comparator) 12, and the ignition timing currently requested by the engine is determined to be 2.
Roughly determine the position between the two ignition timing maps MBT and MAPSTD, and adjust the overall correction values K and ΔMA.
PMBT is determined by ΔMAPMBT=MBT−MAPSTD. On the other hand, after the overall correction is completed, the partial correction calculation unit 27 uses a knock signal from the knock determination circuit 12 to generate a grid divided by the engine speed N and the basic fuel injection width To (or suction pipe pressure, intake air amount Q). In each case, a partial correction value RET is determined by a partial correction subroutine to be described later. ! As shown in the flowchart of FIG. 3, this partial correction value RBT, which is
The high and low ignition timing map difference Δ is read out from the judgment criterion A set from the map 17c in the figure and the engine speed N and basic fuel injection width TI) from the map 17d in FIG.
When the predetermined reference value calculated by MAPMT is exceeded,
The overall correction execution determination unit 28 clears the previous overall correction value together with the partial correction value, and causes the overall correction calculation unit 26 to calculate a new overall correction value again. The above operation is shown in the flowchart of FIG. 3. First, in step 8100, it is determined whether the overall correction is executed at the start of control and the flag FTCMP=O.
If FTCMP=O, the process advances to step 5101, and the overall correction execution subroutine is executed as described later. On the other hand, if FTCMP=1, the process advances to step 3102, where a partial correction execution subroutine is executed as described below.Next, in step 5103, the overall correction execution determination reference coefficient A is set according to the engine speed N. Then, in step 5104, the high-low ignition timing map difference ΔMAPMBT is searched and determined from the map 17d in FIG. 6 using the engine speed N and the basic fuel injection width Tp. 5105
, the absolute value of the partial correction value is a predetermined reference value ΔMAP
It is determined whether or not it exceeds MBT-A, and if it is within, the partial correction execution subroutine is continued using the current overall correction value. On the other hand, if the partial correction value exceeds the predetermined reference value, the process moves to step 3106, where the previous overall correction value including the partial correction value is cleared next time, and the flag FTC is cleared.
Reset MP via step 3100 to step 5
The process returns to the overall correction execution subroutine 101. In this way, in step 5107, the ignition timing 5PKreal to be actually output is determined by the overall correction value and the partial correction value.
This ignition timing signal is output to the ignition device 21 via the output circuit 19, and ignition is performed at the ignition timing. Next, in FIG. 7 showing the details of the functional configuration of the microprocessor 18 that performs the overall correction and the partial correction, the basic ignition timing calculation means 30 calculates the , outputs the obtained basic ignition timing output signal 5PKtot, becomes the signal 5PKreal via the synthesizer 31, and drives the ignition device of the engine 32. Further, the ignition timing correction means 33 uses the engine speed N and the intake air pressure as parameters.
It has a map in which the correction amount RET of the ignition timing is written in the grid No. 16, and the correction signal S P K prt is outputted to the synthesizer 31 and synthesized with the signal S P K tot. The correction number holding means 34 has a similar map for holding the number of corrections, and outputs the output signal NUM from the learning song 111f!
i, is outputted to the holding means 35 and knock occurrence interval judgment value means 36. On the other hand, knocking that occurs while the engine 32 is operating is
A signal about the knock intensity value detected by the knock sensor 7 and taken into the knock occurrence interval/intensity calculation means 37 is given to the gain map 38 .
The signal KNK extracted from the learning curve holding port PI)3
The ignition timing correction amount map RBT of the corresponding ignition timing correction means 33 is multiplied by the correction coefficient LN from 5 by the multiplier 41.
Rewrite the value of. Further, the signal regarding the knock occurrence interval is compared with the output signal (judgment value ADJ) from the knock occurrence interval determination means 36 in a comparator 39, and the comparison result is inputted to the advance angle value setting means 40 and the advance angle value ADV. is adapted to rewrite the value of the corresponding ignition timing correction map RET. In the above configuration, the overall correction subroutine will be explained with reference to the flowchart shown in FIG. First, in step 3200, the values of MAPSTD of the two maps 17a and 17b in the ROM 17 (basic map The ignition timing value at the address in question) and the MBT value (ignition timing value at the address in the MBT map) are read out.Next, in step 5201, ΔMAPMBT, which is the difference between the two, is found. ΔMAPMBT=MBT-MAPSTD Then, in order to obtain the corrected ignition timing value, the value of the basic map MAPSTD is corrected based on ΔMAPMBT, but in order to obtain the correction amount, the value of ΔMAPMBT is divided by a predetermined calculation method. , the range of variation in the coefficient multiplied by ΔMAPMBT is determined as shown in FIG. 4(C). Therefore, the current driving state is a judgment area for determining the coefficient K, for example, M
More than a few degrees between APSTD and MBT (ignition timing M)
Step 3202
Determine by Here, if it is outside the determination area, step 52
07, but if it is within the determination area, step 520
Move to 3. In step 5203, it is determined whether or not knocking has occurred, and if so, the process moves to step 8206; if not, the process moves to step 5204, where it is determined whether a preset predetermined time interval has elapsed since the knocking stopped. is determined, and if the predetermined time has not passed, step 52
If the predetermined time has elapsed, the process proceeds to step 5205 where the coefficient is increased. On the other hand, if knocking occurs, the process proceeds to step 5205 where the coefficient is decreased (8It K).
Proceed to 206. In steps 5205 and S206, the coefficient K in the above-mentioned calculation method for the amount of ignition time correction corresponding to each knock is determined. here,
If the initial value of the coefficient is 1/2, the initial value of the correction amount Δ is 1/4. When the initial value of the coefficient is 0 or 1, the value of the correction amount Δ is 1/2. In this case, the person in charge T
The initial value of & can be anywhere, the value of the first coefficient is 1/2°, the value of the next coefficient is 1/4, etc.
The coefficient is decreased or increased by 1/2 each time the correction is made, and the correction coefficient gradually converges to a certain point depending on the presence or absence of knocking.In step 5207, it is determined whether the correction amount ΔK has decreased to a predetermined value. is determined, and if the correction amount ΔK is greater than a predetermined value, will it be +? at the next occurrence of knocking. Step 5208 allows the import of four reports.
The flag FTCMP is reset to 0, but the correction amount ΔK
has converged to a predetermined value or less, it is determined that the overall correction has been completed, and the flag FTCMP is set to 1 in step 5209.
Set to . In this way, in step 5107 of FIG.
The value of the ignition timing is calculated from the following formula: SPKtot=MAPSTD+K・ΔMAPMBT. In the above embodiment, the resolution of the coefficients is determined by determining the minimum value for the correction amount. When the overall correction is completed, the value of the basic model of ignition timing is applied to the entire control region for the given coefficient K. That is, the basic ignition timing setting means 30
The output signal of will take a value corrected by the above coefficient. Next, the case where the flag FTCMP is set to 1 and the process moves to the partial correction subroutine will be described with reference to the flowchart of FIG. First, in step S300, engine speed and intake air pressure (or intake air amount, basic fuel injection width)
is calculated, and it is determined in the next step S301 whether or not the current operating state is within the control range targeted for partial correction.If it is within the range, in step 5302, the previous ignition timing is Correction amount 5PKprt, number of corrections NtJ
M is retrieved from the ignition timing correction amount mapper Vi33 and the correction number holding map means 34, and step 53
In step 5304, the correction coefficient LN is obtained from the learning curve holding means 35, and the determination value ADJ is obtained from the knock occurrence interval judgment means F13G, respectively, corresponding to the output signal NUM of the correction number holding means 34. Next, in step 5304, the knocking It is determined whether or not knocking has occurred, and when knocking has occurred, the knock intensity and knock occurrence interval are calculated by means 37, and the resulting retardation amount KNK is calculated by gain map 38.
, read by search in step 5305,
In step S306, the retard amount KNK and the correction coefficient LN are
are multiplied by the multiplier 41 to obtain the actual retard amount RETr.
Calculate eal. Then, in step 5307, the retardation amount RB T re is calculated from the previous correction amount S P K prt.
A new S P K prt is obtained by subtracting al, and is stored in the ignition time correct amount map 33. On the other hand, if no knocking occurs, step 8
At 308, it is determined whether or not the knock occurrence interval calculated by means 37 is longer than the knock occurrence interval determination value ADJ, and it is determined that it is longer (knocking did not occur for a certain period of time).
If so, in step 5309, the previous correction amount S P K
Add the advance angle in prt and 1ADV to obtain the new correction amount S.
Determine P K prt 0 Then step 9310
, this new correction amount 5PKprt is (MBT-
3PKtot), and prevents the actual ignition timing from advancing beyond the MBT. However, if it is larger, in step 5311, (MBT-3
PKtOt ) is set as a new correction amount S P K prt, and if it is smaller, it is stored as is in the ignition timing correction amount map 33 in step 5312. In this way, the partial correction subroutine 5102 (
3), step 510 is completed, as described above.
In step 5, it is determined whether the partial correction amount S P K prt exceeds a certain reference value. This base 1! value is. In partial correction, the gap is too large, and the basic ignition timing M (model) is determined to a value that is considered better to be changed as a whole. If the value is not exceeded, the partial correction subroutine 5102 is continued, but if it is exceeded, this means that the overall correction coefficient K is large and deviates from the actual value, so the overall correction will be performed again next time. . Cause of large deviation of this coefficient K (disturbance)
is a change in engine parameters such as a change in the octane number of gasoline, a compression ratio, or a change in spark plugs, so the reference value is calculated as ΔMAP, which is the difference in ignition timing under that operating condition.
It is conceivable to determine the value as a percentage of MBT or simply a constant value, but as mentioned earlier, the knock limit changes due to a temporary rise in intake temperature, such as when restarting or driving in traffic jams. In order to eliminate the inconvenience that the partial correction value SPK prt becomes large and the overall correction is executed again, as shown in FIG. Since ΔMAPMBT-A is set as the reference value, it is possible to prevent an unnecessary return to the overall correction subroutine due to a temporary rise in intake temperature, and it is possible to learn the ignition timing in a stable manner. Through the above-mentioned overall correction and partial correction, the ignition timing value S P K real that is actually output is determined by the following formula: 5PKreal=SPKtot +SPKprt=MA
PSTD+K・ (MBT −MAPSTD> + S P K prt is obtained. [Effects of the Invention] As described above, according to the present invention, the overall ignition timing characteristics are roughly determined based on the signal from the knock sensor. In ignition timing learning control that consists of correction and partial correction that corrects each small area, when the partial correction amount becomes larger than a certain reference value, the previous overall correction is invalidated and a new overall correction is performed. The judgment criteria are set according to the engine speed, so even if there is a temporary change in the knock limit due to a rise in intake air temperature, such as when restarting or when the engine speed is low due to traffic jams, partial correction is possible. This feature does not affect the execution of overall corrections that should be made to account for changes in gasoline octane and the engine over time.
Stable ignition timing learning becomes possible.

[Brief explanation of the drawing]

1 to 9 show an embodiment of the present invention,
Fig. 1 is a block diagram showing the configuration of the ignition timing WfJ control device, Fig. 2 is a block diagram showing the schematic functional configuration of the ignition timing control device, Fig. 3 is a flowchart showing the outline of the ignition timing correction operation, and Fig. 4 is a diagram showing two high and low ignition timing maps and the range of change in the overall correction coefficient, Figure 5 is a map showing the overall correction execution criteria ■ map, Figure 6 is a high and low ignition timing difference map, and Figure 7 is a map of the ignition timing control device. A block diagram showing the specific functional configuration, FIG. 8 is a flowchart of the overall correction subroutine,
FIG. 9 is a flowchart of the partial correction subroutine. 1... Suction pipe pressure sensor, 4... Rotation speed sensor (crank angle sensor), 7... Knock sensor, 18...
Microprocessor, 20... Ignition timing control device, 2
5... Ignition timing calculation section, 26... Overall correction calculation section,
27... Partial correction calculation unit, 28... Overall correction execution determination unit. Patent Applicant Fuji Heavy Industries Co., Ltd. Representative Patent Attorney Jundo Kobashi Patent Attorney Susumu Murai Figure 4 (b) (o)△M
APMBT-MBT-MAPSTD (C) All pages 4^Masakatsushi Tokikinu SPK-MAPSTD+K・△MA
PMBT Figure 5

Claims (1)

[Claims] Necessity of ignition timing control in detecting intake air pressure (or intake air amount) and engine speed, setting the ignition timing value at that time, and correcting the ignition timing value when knocking is detected. In order to determine the overall correction coefficient for the area, this is taken in and calculated at the start of control, and the result is applied to the overall ignition timing correction for the area that requires control.In the next stage, the intake air pressure (or intake air Each partial correction value of the map, which is divided using parameters such as quantity) and engine speed, is learned and updated under predetermined conditions and is applied to the overall correction ignition timing value, and the partial correction value is In ignition timing learning control that is configured to return to the overall correction when a set reference value is exceeded, the above reference value, which determines whether to invalidate the previous overall correction and perform a new overall correction, is set to the engine rotational speed. An ignition timing control device characterized in that the ignition timing control device is configured to set according to.