JPS6043174A - Ignition timing controlling device of engine - Google Patents

Abstract

PURPOSE:To improve response in knocking restricting control by a method wherein differences from the reference ignition timing of an engine to the actual knock limit ignition timings of each cylinders are obtained and the average value thereof is memorized into memories corresponding to the operating conditions of respective cylinders of the engine as a memory correcting value with a predetermined period of renewing. CONSTITUTION:A reference control value generating means 3, providing respective operation condition of an engine with ignition timing characteristics, which are utilized as references, and a means 7, operating sequential correcting values of ignition timing based on the outputs of a knocking detecting means 5 for respective cylinders discriminated by an ignition cylinder discriminating means 4, are provided in the device. The correcting and controlling values are renewed and memorized into addresses corresponding to respective operating conditions of the engine. A memorizing means 6, reading out the memorized values in the corresponding addresses by the detecting outputs of a revolving number detecting means 1 and a load detecting means 2, is also provided in the device. The ignition timings of respective cylinders are determined by the correcting and controlling values of respective cylinders, obtained by a control value operating means 8 operating the sequential correcting values of respective cylinders, the read-out memorized values and control values, operated from these outputs and the reference control value, through an ignition means 9. Thus, the restriction of knocking may be effected with good accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an ignition timing control device that controls the ignition timing of an engine.

[Background of the invention]

In general, it is known that, in terms of output and fuel consumption characteristics, an engine is most efficient when operated at an ignition timing at which slight knocking occurs (knock limit).

This type of conventional device retards the ignition signal, which is generated based on preset reference ignition timing characteristics, by a predetermined angle each time knocking occurs, or by a predetermined angle depending on the knocking intensity. In some systems, when no knock occurs, the ignition timing is feedback-controlled to the ignition timing at the knock limit by decreasing the retard phase shift amount with a predetermined time constant. However, in order to suppress knocking, all cylinders are retarded in the same way with a specific retard phase shift control amount, so if knocking occurs in a certain cylinder, not only the cylinder where knocking occurs, but also the other cylinders are also controlled. The retard angle is controlled uniformly depending on the amount.

In general, each cylinder of an engine has different knock occurrence conditions due to slight structural differences, variations in component parts, differences in air-fuel mixture distribution between cylinders, and the like. That is, the knock limit ignition timing differs for each cylinder.

Therefore, if a conventional device that performs such control is used,
The ignition timing is set to the knock limit of the cylinder where knocking is most likely to occur. This does not necessarily result in optimal ignition timing control for the engine, and does not mean that all cylinders are ignited at the ignition timing at the knock limit.

Therefore, several proposals have been made for cylinder-specific ignition timing control devices that perform feedback control of the ignition timing retard phase shift control amount for each cylinder.

By the way, in this type of feedback control, including control for each cylinder, the control for suppressing knocking is to control the amount of retardation from the reference ignition timing. For this reason, the reference ignition timing must be set in advance at a point that is more advanced than the knock limit. Therefore, the ignition timing at the start of control is always at a point that exceeds the knock limit, so that large knocking occurs at the start of control. It is desirable to set the reference ignition timing to an ignition timing that is slightly ahead of the knock limit. However, if the above-mentioned variation in the knock limit between cylinders is also taken into consideration, such setting is practically impossible. Under certain operating conditions, it is inevitable that the reference ignition timing will be set on the delayed side with respect to the ignition timing at the knock limit.

In the operating state of the engine set to the delayed side, the engine will ignite at a timing that is delayed from the optimal ignition timing at the knock limit.
It is not possible to control all cylinders to optimal ignition timing over all operating conditions.

In addition, with conventional devices, even if the operating state of the engine changes, the ignition timing before the change in operating state is applied as is.
A large time lag occurs until the control amount falls within the control target value in the operating state after the change.

That is, the responsiveness to changes in operating conditions was poor. Furthermore, since the control device controls all operating ranges that require knock suppression by changing the magnitude of the feedback control amount, a wide dynamic range is required, and it is necessary to accurately control ignition timing over all operating ranges. It was difficult to do so.

By the way, the occurrence of knocking is influenced by the ignition timing, air-fuel ratio, intake air temperature, intake air humidity, and many other factors among the operating characteristics of the engine.

However, things that depend on changes in natural conditions, such as intake air temperature and intake air humidity, have very long cycles of change, such as one day or one season. Therefore,
Changes in the occurrence of knocking due to these changes also occur over a long period. In other words, the knocking that occurs in a short period of time under the same operating conditions is approximately the same level, and there is no significant difference in the frequency and intensity of occurrence. In other words, since the correction control value required to suppress knocking that occurs in the same operating condition is almost the same in a short period of time, the correction control value that is previously stored in the same operating condition of the engine specified by specific operating parameters The value is controlled as the current correction control value, and if knocking occurs spontaneously during control, it is sufficient to narrow the ignition timing correction range. If this is done, knocking can be suppressed with extremely high precision and responsiveness, and the ignition timing can be controlled to the knock limit. The above-mentioned long-period change factors can be corrected by slowly changing the correction control value.

[Summary of the invention]

In the invention, a correction control value that gives an average value of the knock limit of each cylinder in each operating state of the engine is stored, and a sequential knocking signal obtained by calculating from this correction control value and the knocking signal generated for each cylinder. The standard control value in each operating state of the engine is corrected for each cylinder using a correction value obtained by combining the correction values, and the above correction control value is applied to each cylinder at a predetermined period for the long-period change factors mentioned above. By updating the ignition timing based on the sequential correction values of The object of the present invention is to provide a device for controlling the individual knock limits over the range.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the general configuration of the present invention. The rotational speed detection means 1 detects the rotational speed of a nosepiece (not shown), and the load detection means 2 detects the load state of the engine. The reference control value generating means 6 has a memory, and generates reference control values for providing reference ignition timing characteristics stored in advance in addresses two-dimensionally partitioned according to the engine speed and load condition by the means 1 and 2. Among them, the reference control value of the corresponding address is read out.

The storage means 6 has an area for storing corrected control values in two-dimensionally partitioned addresses corresponding to the rotation speed and load condition, and the read correction control values (memory correction values) are stored in the correction value calculation means. Sent on 7th. The correction value calculation means 7 inputs the cylinder identification signal of the cylinder identification means 4 and the knocking signal detected by the knock detection means 5, calculates a sequential correction value for knocking suppression of each cylinder from these signals, and calculates the knocking suppression value for each cylinder. By correcting the stored correction value with the value, an ignition timing correction value is created and outputted to the control value calculation means 8. Here, the sequential correction value for each cylinder is updated in the retard direction if knocking occurs, and in the advance direction if knocking does not occur. The correction value can be used not only for correction on the retard side but also on the advance side. Further, the correction value calculation means 7 calculates an average sequential correction value from the sequential correction values of each cylinder every predetermined engine operation period, corrects the correction value, and updates and stores the result in the corresponding storage area. The control value calculation means 8 corrects the previously read reference control value with the ignition timing correction value created by the correction value calculation means 7 corresponding to the cylinder to be ignited this time, determines the ignition timing, and then adjusts the ignition timing to the ignition timing. The ignition is performed at the ignition timing determined in step 9.

FIG. 2 is a block diagram showing an embodiment of the present invention applied to a four-stroke, four-cylinder engine. In the figure, 10 is an angle detector that generates a signal 10a whose signal level is inverted every 36o0 of rotation angle of the crank in conjunction with the rotation of the camshaft of the engine, and 11 is a position relative to the signal 10a of the angle detector 10. An angle detector that generates a signal 11a with a phase difference of 180°, 12 a pressure sensor that detects the intake pipe pressure of the engine and generates a signal 12a corresponding to the pressure, and 16 a signal 12a output from the pressure sensor 12. Analog/digital (A/D) converts the signal into a digital signal 13a.
) Converter, 14 is an acceleration sensor attached to the engine and detects the vibration acceleration of the engine and outputs a signal 14a; 15 is a converter that discriminates the period in which engine knocking occurs from the signal 14a of the acceleration sensor 14, and outputs a signal 15a; A discriminator that
16 is an A/D converter that digitizes the signal 15a of the discriminator 15 into a signal 16a. 2o is a microcomputer, which is composed of a microprocessor (CPU) 21, memory (ROM and RAM) 22, and an interface (Ilo) 23. 18 is a timing conversion circuit that converts the ignition timing control amount signal 23a calculated by the microcomputer 2o into a timing signal 18a, and 17 is an ignition circuit that ignites the engine with the timing signal 18a generated by the timing conversion circuit 18.

Next, the operation of this embodiment configured as described above will be explained. Figure 3 shows the angle detector 10.11 shown in this embodiment.
The signal 11a of the angle detector 11 changes to L" level at 90° BTDC of the first cylinder and becomes H" level at 90° BTDC of the fourth cylinder in accordance with the rotation of the engine. Further, the signal 12a of the angle detector 12 is a signal delayed by 18 oo in crank angle with respect to the signal 11a of the angle detector 11. These two signals 11 a + 12
a is the interface 2 of the microcomputer 2o
6 is input. The pressure sensor 12 detects the intake pipe pressure of the engine and generates a signal f2a at a voltage level corresponding to the pressure. Here, since the intake pipe pressure of the engine changes sensitively in response to the load state of the engine, the load state of the engine can be known from the level of the signal 12a obtained by detecting this intake pipe pressure. Now, the signal 12a generated from the pressure sensor 12 is digitized by the A/D converter 13,
The signal becomes a signal 13a and is input to the interface 26.

On the other hand, the acceleration sensor 14 is attached to the engine and constantly detects vibrations of the engine and the engine. The signal 14a, which is the detection output, contains a noise signal caused by mechanical vibration caused by engine operation and a knocking component caused by vibration caused by knocking of the engine. The discriminator 15 discriminates and detects the knocking component from the signal 14a, further integrates it, and generates a signal 15 having a level corresponding to the knocking intensity.
Output B. This signal 15a is digitized by the A/D converter 16 to become a signal 16a, which is read into the CPU 21 via the interface 26. Still, the integral value of the discriminator 15 is reset by the signal 23b from the interface 26 under the command of the microprocessor 21, and is initialized for the next knocking detection.

The memory 22 of the microcomputer 20 is ROM and RA.
M, and the ROM has an area (hereinafter referred to as an advance angle map) that stores reference control values that are predetermined according to the engine speed and load state and give reference ignition timing characteristics in each operating state of the engine. ) is provided in the RAM, and in each address determined corresponding to the engine speed and load condition, an area (
A learning map (hereinafter referred to as a learning map) is provided.

The CPU 21 determines the optimal ignition timing for each cylinder based on sensor information from the angle detectors 10, 11, the pressure sensor 12, and the acceleration sensor 14, and causes the timing converter 18 to output a signal 18a at the determined ignition timing. The ignition circuit 11 ignites the engine.

A flowchart of the processing executed by the CPU 21 is shown in FIG. P1 to P3s in the figure indicate each step of the flowchart.

In this flowchart, ignition is the first step. 3rd degree 2nd degree.
The case of a four-cylinder engine is shown in which the fourth cylinder is operated in this order.

The control calculation by the CPU 21 is performed once per ignition inter-period.
．． This is performed in synchronization with the timing at which the state of the output signal of the second angle detector 10.11 is reversed.

First, the counter of the timing conversion circuit 18 is incremented to 7 by the PI, and a counting operation is started.

At P, the time interval from the previous processing start time to the present time, that is, the period corresponding to 180° rotation of the crank angle is measured. P converts this measured period into the number of revolutions. P4
Input the pressure signal at P, and calculate the engine load condition from the lever signal.

At P6, the state of the signal 10a of the angle detector 10 is checked. If the state is "L", as shown in FIG. 3, the cylinder that was ignited immediately before is the first cylinder or the second cylinder. Next, check the state of the second angle detector 110 signal 11a at P, and if the output state is "L", the immediately preceding ignition cylinder is identified as the first cylinder, and the ignition cylinder identification information is read at pm. In order to store the first
The number 1 indicating the firing order of the cylinders is memorized. Signal 1t at P7
If the state of a is "H", the number 4 indicating the firing order of the second cylinder is stored in register n with P. On the other hand, the first
If it is determined that the signal 10a of the angle detector 10 is °H'', the immediately preceding ignition cylinder is the third or fourth cylinder.Hereinafter, P. In the case of P7, the angle detector 1
Check the state of the signal 11a of "1", and if it is "°'L", p
At tt, the number 2 indicating the ignition order of the third cylinder is stored in the register n, and in the case of 'H', the number 3 indicating the ignition order of the fourth cylinder is stored at the register n at pat.

At P13, after reading the knocking signal 16a (ΔK), a signal 23b for resetting the integral value of the discriminator 15 is generated to prepare for detecting the next occurrence of knocking. In PI4, the read signal 16a (ΔK
) is 0, that is, whether or not knocking occurred in the cylinder due to the previous ignition. If there is no knocking, P6 to P6 of the registers for sequential correction value update provided corresponding to each cylinder in P□ are selected first.
Register D corresponding to the immediately preceding ignition cylinder identified by st
(Add 1 to the nlO value and set this value to register D (nl
be memorized again. Next, at P, 6, it is detected whether the value of this register D (nl has reached 100 or not, that is, whether the signal 16a (ΔK) was 0 during the period of 10 consecutive ignitions of the cylinder concerned, and D (If nl=10, register C (
Subtract 1 from the value of nl and store this value. P.I.
In B, there is a register D fn) that performs the above counting operation.
Reset the value to O and prepare for the next 10 ignition counting operations. On the other hand, when the number of consecutive ignitions has not reached 10 at D(nl-10) in PIB, the value in the successive correction value storage register Cfnl is not subtracted, but the value is held as it is and the process proceeds to the next step 21.

Also, when there is signal 16a at Pt4 (\0 at Δ
) is a register C for sequentially storing correction values in the PIll.
(ΔK is added to the value of nl, and the correction value is increased by the amount corresponding to the knocking intensity. At the next pto, the value of the ignition number counting register D (nl is reset, and preparation is made for 10 ignition measurement operations.

Therefore, if it is determined that there is knocking from the signal 16a detected every ignition of the relevant cylinder, the value of the register C (nl) for storing correction values that increases or decreases depending on the state of knocking will depend on the knocking intensity. If there is no knocking, the value is updated by 1 in the decreasing direction for every 10 ignitions of the relevant cylinder.In this case, the range of change is centered around zero, from the positive pole to It is set so that it can take either value for the negative electrode. Note that the count of 10 ignitions that determines the gain in the decreasing direction is one example, and is not limited to this.

In this way, when the correction values of the cylinders in which knocking has occurred are updated in response to the signal 16a caused by the previous ignition, the process of updating the stored correction values stored in the learning map is then started after PTT.

At PH1, the memory correction value stored at the corresponding address of the learning map is read out to the B register based on P, and the rotational speed and load condition determined by P. Next, B.

Then, the engine speed at the time when the engine steady state counting register E, which will be described later, starts counting is compared with the engine speed P, and if the difference is 5 or more or more, it is determined that the engine speed has changed. In the process of P31, if the jump change is less than 50 rpm, it is determined that the engine is being operated at a constant rotation speed. In the next pis, similarly check the change in the load state from the start of counting in register E. Change in load status is 5
If the engine is operating more than
Proceed to processing.

On the other hand, if the change is less than 5 inches, it is determined that the engine is being operated under a constant load and the process proceeds to Pt4. At Pt4, the value of register E that counts the steady operating state of the engine is set to 1.
Add. In Pt5, the count value of this register E is 10.
0, that is, whether the engine has been operated at constant rotational speed and constant load over 100 consecutive ignitions. If 100 ignitions have not been reached, proceed to Pas. If E=100, P2
6, the average value of the sequential correction values for each cylinder is calculated and stored in register F. At the next Pt, the average value of the sequential correction values is added to the stored correction value previously read from the learning map at pt+ and stored in the B register, and the result is stored in the B register again. In the process, the changed value of the B register is updated and stored in the corresponding storage area on the learning map. At pto, the average value F of the sequential correction is subtracted from the sequential correction value of each cylinder to update the sequential correction value of each cylinder. P,
. Now, in preparation for the next update of the memory correction value, clear the steady state counting register E, and store the engine speed and load condition at this point as a reference for determining the steady state.
Proceed to pss. On the other hand, h! Or, if it is determined that the operating state of the engine is fluctuating in PTS, the steady state counting register E is cleared in PSS, and the engine rotation speed and load state are stored as the standard for steady state determination from the next ignition. P23
Since the sequential correction values for the cylinders in the operating state before the change are meaningless in the operating state after the change, they are all set to 0 and the process proceeds to pss. In this way, the memorized correction value on the learning map is calculated as follows:
Updated if continuous for the number of ignitions. The update is
Because knocking is suppressed for each cylinder, the average correction value is always zero.

That is, the correction value for each cylinder is updated sequentially so as to correct only the variation from the average for each cylinder.

Further, when the engine is not in a steady state, updating of the correction value is prohibited, and meaningless updating of the correction value in the knocking suppression state before the engine operating state changes is prevented.

In updating this correction value, it is determined that the engine is in a steady state when the engine speed fluctuation is less than 5 Orpm and the load fluctuation is less than 5%, but this is just one example. Other criteria may be used as the determination condition. Furthermore, although the number of engine ignitions is counted and the correction value is updated when the number reaches a predetermined number, this update may be performed every predetermined time period.

Now, when the process of updating the correction values on the learning map is completed in this way, the process of determining the ignition timing of the cylinder to be ignited this time begins.

In Pss, in order to identify the cylinder to be ignited this time,
Add 1 to the firing order n of the previously fired cylinder. That is, for example, if the previous ignition was in the first cylinder, the value of register n is 1, and by adding 1 to this, the value of register n becomes 2, and the corresponding cylinder in the ignition order is the third cylinder.
It is a cylinder.

In Pl4, the value of register n is calculated by pss; 5
Check whether it has become. If n=5, the previous ignition cylinder was the 2nd cylinder, and this time the ignition order is the 1st cylinder.
Since this is a cylinder, the value of register n is set to 1 in pss. This process determines the current ignition cylinder. paa
Register B (P21
, and if the process from P26 to pso is passed, the updated correction value is stored) and the sequential correction value register C (nl) corresponding to the cylinder to be ignited this time. (If updated by P2O, the updated value) is added to create the ignition timing correction value.P3?
Now, read out the reference control value at the address on the advance angle map that corresponds to the rotation speed and load condition determined by Ps l P5, and
, 6 is subtracted from the ignition timing correction value to create a control value for determining the ignition timing of the cylinder to be ignited this time.

The control value as a result of this calculation is data indicating the ignition position by a value equivalent to the angle, and P5. , this data is converted into delay time data from the output inversion time of the angle detector 11 or 12 (counter count start time at Pl). This angle-to-time conversion calculation is easily possible based on period information in P.

The ignition timing control value converted to time at pao is set in a latch of timing converter 18.

The timing converter 18 has a counter, and when the microcomputer 20 starts processing,
That is, counting is started from the time when the output state of the first or second detector 10.11 is reversed. When the value of this counter matches the value of the latch set in PSQ, timing converter 18 generates a ignition signal and ignition circuit 11
The ignition coil of the microcomputer 2 is de-energized.
The engine is ignited at the ignition timing determined by 0.

In this way, this embodiment determines the steady operating state of the engine, and in the steady state, the average value (median value) of the correction values that provide the knock limit ignition timing for each cylinder is used as the correction value to adjust the engine operating state on the learning map. By creating a sequential correction value for each cylinder using the knocking signal stored in the corresponding address and detected every time the engine ignites, the standard ignition timing is corrected for each cylinder using this sequential correction value and the above-mentioned stored correction value. , allowing each cylinder to be controlled to its individual knock limit period. On the other hand, updating of the correction value is prohibited during engine transient operating conditions, and the ignition timing of each cylinder is corrected using the correction injection that has already been set under steady state conditions. Even if the ignition timing changes, the ignition timing of each cylinder is controlled to the average ignition timing of the knock limit of the valley oil in the operating state after the change. That is, since only the variation in the knock limit between cylinders is corrected using the sequential correction value created by the knock signal,
Ignition timing feedback control has very good responsiveness.

Furthermore, since the sequential correction value for each cylinder only needs to correct the variation from the average of the ignition timing that gives the knock limit of each cylinder, the control 1 [IIχ range is narrow, that is, a wide dynamic range is not required. , it becomes possible to improve control accuracy.

However, since the correction value on the learning map and the sequential correction value for 6kii≦1 can take values of both positive and negative polarity, it is possible to control the ignition timing to the advanced side beyond the standard ignition timing. Therefore, even if the standard ignition timing is set to the retard side than the ignition timing at the knock limit, the memory correction value is updated in the advance direction, and the ignition timing at the knock limit for each cylinder is updated in all operating conditions. It becomes possible to drive.

In this embodiment, when updating the correction value, the update amount of the correction value is created by simply arithmetic averaging the sequential correction values of each cylinder. Depending on the polarity, an update amount may be created using a method such as weighting and averaging, and the stored correction value may be updated. Further, in this embodiment, the cylinders are identified based on the output information of the two angle detectors, but the method is not limited to this method. For example, a detection means for identifying a reference ignition cylinder may be provided to sequentially count the ignitions. Even if there is a method for identifying cylinders, the essence of the present invention is not affected in any way.

〔Effect of the invention〕

As described above, according to the present invention, the reference ignition timing of the engine is set in advance corresponding to each operating state, and the difference between the reference ignition timing and the actual knock limit ignition timing of each cylinder is determined in advance. is applied to the knocking signal, and the average value of this difference is used as a memory correction value to update and store it in a read/write memory corresponding to each operating state of the engine's live cylinder at a predetermined cycle, thereby eliminating variations in the engine side. , by absorbing variations in the ignition timing of the knock limit due to seasonal changes, secular changes, etc., and suppressing the occurrence of knocking that occurs in a short period of time with slight sequential correction amounts using the knocking signal. Knocking can be suppressed with high precision. In addition, even if the engine operating condition changes, the ignition timing of each cylinder is quickly controlled to the average ignition timing of the knock limits of each cylinder, preventing large knocks from occurring during transient periods.
Deterioration of engine performance due to transient retardation is prevented. Furthermore, since the standard ignition timing can be corrected to the advanced side, even in operating modes where the standard ignition timing is set to the retarded side with respect to the knock limit ignition timing, each cylinder can be adjusted to the standard ignition timing. While the actual control ignition timing is controlled to the advanced side, feedback control can be performed individually using the knocking signal. Therefore, in all operating conditions, each cylinder is controlled by the optimum ignition timing at the knock limit, and it is no longer necessary to set the reference ignition timing on the advanced side with respect to the ignition timing at the knock limit.

For example, by setting the reference ignition timing with the center value of the knock limit of each cylinder as the target, it is possible to prevent the occurrence of large knocking at the start of control due to the reference ignition timing advancing too much.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the general configuration of the device of the present invention, and FIG.
The figure is a block diagram showing one embodiment of the device of the present invention, Figure 3 is a waveform diagram of the output of the angle detector shown in Figure 2, and Figure 4 is a waveform diagram of the output of the angle detector shown in Figure 2.
3 is a flowchart of the operation of the microcomputer shown in the figure. 1... Rotation speed detection means, 2... Load detection means, 6.
. . . Reference control value generation means, 4. . . Cylinder identification means, 5.
Knock detection means, 6. Storage means, 7. Correction value calculation means, 8. ft+li control value calculation half value calculation means/ignition means. Agent: Masuo Oiwa Procedural Amendment (voluntary) Showa Limo 12"/61-1 ; Monk ↑, 1mi To the Director General of the Office 1, Indication of Tenancy Patent Application No. 58-151285 2, Name of Invention Engine Ignition Timing Control Device 3, Name of the person making the correction Name (601) Mitsubishi Electric Corporation Representative Kata 111 Jin 8 Department 4 Agent (i゛ Address Higashijiji Miyakochiyo 11-1 Ward Marunouchi 2-chome [-
No. 12; No. 3 Mitsubishi Electric Corporation -5 5. Subject of amendment (1) Full text of the specification (2) Drawing 6. Contents of amendment (1) The entire text of the attached joint specification will be amended. (2) Correct the attached circular, Figure 3. (3) Correct the attached circular, Figure 4. 7. List of attached documents (1) A document containing the entire text of the amended specification 1 copy (2) A document containing the amended Figure 3 1 copy (3) A document containing the amended Figure 4 1 Specification (full text) L Name of the invention Engine ignition timing control device 2, % Claims A knocking detection means for detecting knocking of the engine, an operating state sensor for detecting the operating state of the engine, and an engine ignition timing control device 2. Means for generating a reference control value that provides reference ignition timing characteristics for each operating state. cylinder identification means for identifying an ignition cylinder of the engine; means for generating a sequential correction value for ignition timing based on the output of the knock detection means for each cylinder identified by the cylinder identification means; updating and storing a correction control value obtained by calculating the sequential correction value of each cylinder in the operating state at a predetermined cycle at an address corresponding to each operating state of the engine;
A memory means capable of reading out the stored value of the corresponding address according to the detection output of the driving state sensor, and this readout t''Lf.
control value calculating means for calculating all of the c memory values and the sequential correction values for the cylinder to generate all the ignition timing correction control values for the cylinder;
Calculate I from the output of this control value calculation means and the above reference control value.
An engine ignition timing control device comprising: determining means for determining the ignition timing of each cylinder based on the n-th control value. 3. Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to an ignition timing control device that controls the ignition timing of an engine. [Background of the Invention] In general, it is known that an engine is most efficient when operated at an ignition timing at which slight knocking occurs (knock limit) in terms of output and fuel efficiency characteristics. In this type of conventional device, a large point signal generated based on preset reference ignition timing characteristics is retarded by a predetermined angle each time knocking occurs, or by a predetermined angle depending on the knocking intensity. , by reducing this retard phase shift amount with a predetermined time constant when knocking does not occur.
There was one that feedback controlled the ignition timing to the ignition timing at the knock limit. However, it is necessary to suppress knocking (all cylinders are retarded in the same way using a specific retard phase shift control amount, so if knocking occurs in one cylinder, not only the cylinder in which knocking occurred, but also other cylinders will also be controlled). In general, each cylinder of an engine has different knock occurrence conditions due to slight differences in structure, variations in component parts, differences in air-fuel mixture distribution between cylinders, etc. In other words, the ignition timing at the knock limit is different for each cylinder. Therefore, if a conventional device that performs such control is used, the ignition timing will be set at the knock limit of the cylinder where knocking is most likely to occur. Don't settle for a setting of 1. This does not necessarily mean that all cylinders will be ignited -3n at the ignition timing of the knock limit. Several proposals have been made for cylinder-specific ignition timing control devices that perform feedback control of the ignition timing retard phase shift control amount for each cylinder.By the way, this feedback control includes control for each cylinder as well. Therefore, the control for suppressing knocking is to control the amount of retardation from the reference ignition timing.For this reason, the reference ignition timing must be set in advance at a point that is more advanced than the knock limit. Therefore, the ignition timing at the start of control is always at a point K that exceeds the knock limit, so large knocking occurs at the start of control.The reference ignition timing is set to an ignition timing slightly ahead of the knock limit. However, if we also take into account the variation in knock limits between cylinders mentioned earlier, it is practically impossible to set such a setting.In certain operating conditions, the ignition at the knock limit It is unavoidable that the reference ignition timing is set on the delayed side of the engine timing.In the operating state of the engine that is set on the delayed side, the engine will ignite at a timing that is later than the optimal ignition timing for the knock limit, and all It is not possible to control all cylinders to the optimum ignition timing over the operating conditions of the engine.In addition, with conventional devices, even if the operating condition of the engine changes, the ignition timing is the same as that before the operating condition changes. For,
A large time lag occurs when the control amount reaches the control target value in the operating state after the change. That is, the responsiveness to changes in operating conditions was poor. Since the control device and 17 control all the operating ranges that require knock suppression through thick changes in the feedback control amount, a wide dynamic range is required.
It has been difficult to accurately control ignition timing over all operating ranges. Incidentally, the occurrence of knocking depends on the ignition timing, air-fuel ratio, intake air temperature, intake air humidity, and many other factors among the operating characteristics of the engine. However, things that depend on changes in natural conditions, such as intake air temperature and intake air humidity, have very long cycles of change, such as one day or one season. Therefore,
Changes in knocking p occurrence status due to these changes are also -1
This results in a long period. In other words, the knocking that occurs in a short period of time under the same operating conditions is about the same as t-γ, and there is no significant difference in the frequency of occurrence or the remaining amount. First, since the correction control value required to suppress knocking that occurs under the same operating condition is almost the same over a short period of time, the correction control value that is required to suppress knocking that occurs under the same operating condition is almost the same in a short period of time. All control values are controlled as the current correction control value, and the ignition timing correction range can be narrow in case of slight knocking during control, so if the correction control is performed sequentially using the knocking signal for each occurrence, It suppresses knocking with extremely high precision and responsiveness, and can control the ignition timing to the knock limit. The aforementioned long-period change factors can be corrected by slowly changing the correction control value. [Summary of the Invention] This invention stores a correction control value that gives an average value of the knock limit of each cylinder in each operating state of the engine, and uses this correction control value and the knocking signal generated for each cylinder to calculate the knocking signal. The standard control value for each operating state of the engine is corrected for each cylinder using a correction value obtained by combining the sequential correction values obtained by calculation, and the above correction control value is used for the long-cycle change factors mentioned above. By updating based on the sequential correction value of each cylinder at a predetermined period, it is possible to accurately suppress non-knocking with a small number of sequential correction values, and improve the response of knocking suppression control when operating conditions change. An object of the present invention is to provide a device for controlling the ignition timing of the engine to individual knock limits over all operating conditions. [Embodiment of the Invention] An embodiment of the invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the general configuration of the present invention. The rotation speed detection means 1 detects the rotation speed of an engine (not shown), and the load detection means 2 detects the load state of the engine. The reference control value generating means 3 is provided in the memo 9, and is for providing the reference ignition timing characteristic set stored in advance in the addresses divided two-dimensionally according to the engine speed and load condition by the means 1 and 2. Among the reference control values, the reference control value at the corresponding address is read. The storage means 6 has an area for storing all the corrected control values two-dimensionally in the section -g:nfc address corresponding to the rotational speed and load condition, and the read out correction control value (memory correction value) is the correction value. The signal is sent to the calculation means 7. The correction value calculation means 7 inputs the cylinder identification signal of the cylinder identification means 4 and the knocking signal detected by the knock detection means 5 by -5t.
~, by correcting the stored correction value with the value, an ignition timing correction value is created and output to the control value calculation means 8. Here, the sequential correction value for each cylinder is updated in the retard direction when knocking occurs, and in the advance direction when knocking does not occur. The correction value can be used not only for correction on the retard side but also on the advance side. Further, the correction value calculation means 7 calculates an average sequential correction value from the sequential correction values of each cylinder every predetermined engine operation period, corrects the correction value, and updates and stores the result in the corresponding storage area. . The control value calculation means 8 corrects the previously read reference control value with the ignition timing correction value created by the correction value calculation means 7 corresponding to the cylinder to be ignited this time, and determines the ignition timing. , the ignition can be broken at the ignition timing determined by the ignition means 9. FIG. 2 is a block diagram showing an embodiment of the present invention applied to a four-stroke, four-cylinder engine. In the figure, 10 is linked to the rotation of the engine's camshaft, and the signal level is reversed every 360 degrees of crank rotation. :Ta signal 10a
An angle detector 11 generates a signal 1 of the angle detector 10.
An angle detector 12 that generates a signal 11a'r with a phase difference of 180 degrees with respect to 0a detects the intake pipe pressure of the engine, and a signal 12a'! corresponding to the pressure! ! ? The generated pressure sensor 13 is a signal 12ai that is output from the pressure sensor 12.
An analog-to-digital (A/D) converter 14 is attached to the engine to convert it into a digital signal 13a, and 7J[l] is attached to the engine to detect vibration acceleration of the engine and output a signal 14a.
The speed sensor 15 discriminates from the signal 14a of the acceleration sensor 14 all the periods during which engine knocking occurs, and outputs a signal 1.
5a (j outputs the discriminator, 16 is the signal 15 of the discriminator 15
This is an A/D converter that digitizes the signal 8 into a signal 16a. 20 is a microcomputer, which includes a microprocessor (CI'U) 21 and memory (ROM and RA).
M) 22 and the interface (Ilo” 423
It is composed of -3rt. 18 is a timing conversion circuit that converts the ignition timing control amount signal 23a' calculated by the microcomputer 20 into a timing signal 18a; 17i is an ignition circuit that ignites the engine using the timing signal 18a generated from the timing conversion circuit 18; be. Next, the operation of this embodiment configured as described above will be explained. Figure 3 shows the angle detector 10.1 shown in this embodiment.
1, the signal 10a of the angle detector 10 is "L" at BTI) C90° of the first cylinder according to the rotation of the engine.
” level, 4th cylinder BTDC 90° “H”
become the level. 1, the signal 11a of the angle detector 11 is
1 at the crank angle for the signal 11a of the angle detector 11
The signal is delayed by 80 degrees. These two signals 11a,
12a is input to the interface 23 of the microcomputer 20. The pressure sensor 12 detects the intake pipe pressure of the engine and outputs a voltage level signal 12a (
Here, since the engine intake pipe pressure changes sensitively in response to the engine load state, it is possible to know the engine load state from the level of the signal 12a obtained by detecting this intake pipe pressure. Then, the signal 12a generated from the pressure sensor 12 is digitized by the A/I f converter 13 and becomes a signal 13a, which is input to the interface 23. On the other hand, the acceleration sensor 14 This detection output signal 14a includes a noise signal due to mechanical vibration caused by engine operation and a knocking component due to vibration generated by engine knocking. The discriminator 15 discriminates and detects all the knocking components from the signal 14a, further integrates the signals, and generates a signal -15 having a level corresponding to the knocking intensity.
Outputs 2. This signal 15a is converted into a digital signal by the A/D converter 16 and becomes a signal 16a. The data is read into the CPU 21 via the CPU 21. 1fc, the integral value of the discriminator 15 is reset by the signal 23b from the interface 23 under the command of the microprocessor 21, and the discriminator 15 is initialized for the next knocking detection. Memory 22 of microcomputer 20 ROM and RA
RO'M is an area (hereinafter referred to as advance angle A map (referred to as a map) is provided in the RAM, and an area (hereinafter referred to as "map") is provided in which memory correction values for the operating state corresponding to each address are stored at each address determined by the engine speed and load state. A learning map (called a learning map) is provided. The CPU 21 determines the optimum ignition timing for each cylinder from the sensor information of the angle detectors 1.0 and 11, the pressure sensor 12, and the acceleration sensor 14 [7, Determine - gn signal from the timing converter 18 at the determined ignition timing] The 18ak output was reduced, and the ignition circuit 17 caused a large amount of damage to all points in the engine. A flowchart of the processing executed by the CPU 21 is shown in FIG. P in the figure, ~P5. indicates each step of the flowchart. In this flowchart, ignition is the first step. 3rd゜4th.
A case of a four-cylinder engine in which the second cylinder is fired in order is shown. The control calculation by the CPU 21 is performed once per ignition cycle, and the first
．． [2] is performed in synchronization with the timing when the state of the output signal of the second angle detector 10.11 is reversed. 1. First, the counter of the timing conversion circuit 18 is reset to 0 using Pl, and a counting operation is started. At P2, the entire time interval in the current housing from the previous processing start time, that is, the entire cycle corresponding to 1800 revolutions in terms of crank angle is measured. P converts this measured period into the number of revolutions. P4
Input all the pressure signals at P, and calculate the engine load condition from the lever signals. At P6, the state of the signal 10a of the angle detector 10 is checked. If the state is "L", as shown in FIG. 3, the cylinder that was ignited most recently is the first cylinder or the second cylinder. Next, at P7, check the state of the signal 11a of the second angle detector 11, and if the output state is "°L", the identification whistle 11 indicates that the previous ignition air is in the first cylinder, and at P8, the signal 11a of the second angle detector 11 is checked. In order to store the identification information, the number 1 indicating the ignition 111j of the first cylinder is stored in the ni register n provided in the memory 22. P
, the state of the signal 11a is 'H', and at Po, the number 4 indicating the firing order of the second cylinder is memorized in the register n.On the other hand, at P6, the signal 10a of the first angle detector 10 is set to 'H'. If it is determined to be "■", the immediately preceding ignition cylinder is the third or fourth cylinder.Hereinafter, P.In the same way as P7, check the state of the signal 11a of the angle detector 11, "L"
In the case of "H", the number 2 indicating the ignition order of the third cylinder is stored in the register n at P1, and the number 3 indicating the ignition order of the fourth cylinder is stored in the register n at P12. In Pl, after reading the knocking signal 16a (ΔK), a signal 23b (5) is generated to reset the integral value of the discriminator 15 to prepare for detecting the next occurrence of knocking. Signal 16a (Δ
Check whether K) is 0, that is, whether knocking occurred in the cylinder due to the previous ignition. If there is no knocking, in P4, registers for sequential correction value update provided corresponding to each cylinder are first updated in P6 to P4.
P5. Register D corresponding to the immediately preceding ignition cylinder identified by
(Add 1 to the value of ri and set this value to register D (n)
I remember it again. Next, in Pl6, it is detected whether the value of this register D (n) has reached 10, that is, whether the signal 16a (ΔK) was 0 during the period of 10 consecutive ignitions of the relevant cylinder, and D(n) is detected. -10, register C(n
The value of l? Subtract 1 and memorize this value. In Pus, a register D(n
Reset the lO value to O and prepare for the next 10 ignition counting operations. On the other hand, when the number of consecutive ignitions has not reached 10 in D (n)\10 at P, 6, the value of sequential correction value storage register C (the value of nl is not subtracted, but the value of 11 is held and the next 21 In addition, if there is a signal 16a at Pl4 (\0 at Δ
) is a register C(n
), ΔK is calculated by the force U, and the correction value increases by the amount corresponding to the knocking intensity, and the next P. Now, the value of the register D(n) for counting the number of ignitions is reset to prepare for the 10 ignition measurement operation. Therefore, it is determined that there is knocking from the signal 16a detected every time the relevant cylinder is ignited.
gn, the value is updated in an increasing direction according to the knocking intensity. If there is no meshing, the value is updated in a decreasing direction by 1 every 10 ignitions of the relevant cylinder. In this case, the range of change is centered around zero, and is set such that it can take either positive or negative values with -. Note that the count of 10 ignitions that determines the gain in the decreasing direction is one example, and is not limited to this. In this way, when knocking occurs at signal 16a due to the previous ignition and the sequential correction value of cylinder t reaches a new value, then P2. From now on, it will be memorized in the learning map. The process starts updating the stored correction value. P2. Now, the rotational speed and load condition determined by P and P are read into the memory correction value kB register stored at the corresponding learning map address. Next, in P22, the engine steady state counting register E, which will be described later, compares the number of revolutions at the start of counting with the number of revolutions determined by P, and the difference is 5 Orp.
m or more, it is determined that the engine speed has changed, and P8.
Jump to processing. If the change is less than 5 Orpm, it is determined that the engine is operating at a constant rotation speed, and in the next step P23, the change in the load state from the start of counting in register E is similarly checked. If the change in load condition is 5% or more, it is assumed that a change has occurred in the operating condition of the engine and the process proceeds to P3I. On the other hand, if the change is less than 5-, the operation is under constant load.
rt, and proceed to P, 4. At P and 4, 1 is added to the value of register E that counts the steady operating state of one engine. In P□, check whether the count value of this register E is 100 or not, that is, whether the engine speed is constant during 100 consecutive ignitions and the load condition is steady state. Check whether it is true or not. 100
If ignition has not been reached, P7. Proceed to. If E=100, then P,. Then, the average value of the sequential correction values for each cylinder is calculated and stored in register F. In the next ptt, the average value of the sequential correction values is added to the stored correction value previously read from the learning map at P,1 and stored in the B register, and the result is stored in the B register again. At P and 8, updates are stored and memorized in the corresponding storage area on the IT learning map of the changed B register. In Pill, the average value Ff of the sequential correction is subtracted from the sequential correction value of each cylinder, and the sequential correction value of each cylinder is updated. P. Now, in preparation for the next update of the stored correction value, the steady state counting register Ei is cleared, the engine speed and load condition at this point are stored as standards for steady state determination, and the process proceeds to pss. On the other hand, P2. Or, in P23, it is determined that there is a change in the operating state of the engine 1f17' (
In this case, the steady state counting register E is cleared with P, 1, and the engine speed and load condition are stored as the standard for steady state determination from the next ignition. P2. Since the sequential correction values for each cylinder in the operating state before the change are meaningless in the operating state after the change, they are all set to 0 and the process proceeds to Po. In this way, the stored correction value on the learning map is updated when one engine continues to operate in a steady state for 100 ignitions. The updating is performed in such a way that the average value of the successive correction values for knocking suppression performed for each cylinder always approaches zero. That is, the stored correction value is updated so that the sequential correction value for each cylinder corrects only the variation in the knock limit of each cylinder from the average value. 1, updating of the correction value is prohibited when the engine is not in a steady state, and pointless updating of the correction value in the knocking suppression state before the engine operating state changes is stopped. In addition, in updating this correction value, it is determined that the engine is in a steady state when the fluctuation in the engine speed is less than 50 rpm and the load fluctuation is less than 5 inches, but this is just one example. Other conditions may be used. The number of ignitions of the engine is counted, and the correction value is updated when the number reaches a predetermined number, but this update may be performed every predetermined period of time. After completing the process of updating the memory correction values on the learning map in this way, the process of determining the ignition timing of the cylinder to be ignited this time begins. In pss, in order to identify the cylinder to be ignited this time,
Add 1 to the firing order n of the previously fired cylinder. That is, for example, if the previous ignition was in the first cylinder, the value of the register n is 1, and by adding 1 to this, the value of the register n becomes 2, and the corresponding cylinder in the ignition order is the third cylinder.
It is a cylinder. Check whether the value of register n reaches 5 in the operation of P,, K, Ln, and uPss. If n=5,
The cylinder that was ignited last time was the 2nd cylinder, and this time it is the 1st cylinder in the ignition order, so P2. In this case, the value of register n is set to 1. This process determines the current ignition cylinder. P36
Correct the contents of register B that stores the correction value in (P, , read from the learning map and output C, if the process of P2.~pso is passed, the updated correction value is stored). The ignition timing correction value is created by adding the value to the sequential correction value register C(n) (if updated by Pt., the updated value) corresponding to the cylinder to be ignited this time. In PN, the reference control value of the address on the advance angle map corresponding to the rotation speed and load condition determined in P, , P is read out, the ignition timing correction value determined in P36 is subtracted, and the ignition timing of the cylinder to be ignited this time is determined. Create all control values to be determined. The control value of this calculation result is data that indicates the ignition position by a value equivalent to the angle, and in Pss, this data is used as a delay from the output reversal time of the angle detector 1o or 11 (the counter force start time in P). Convert to time data. This angle-to-time conversion calculation is easily possible based on the period information in P2. The ignition timing control value converted to time at P2O is set in a latch of timing converter 18. The timing converter 18 has a counter, and when the microcomputer 20 starts processing,
That is, counting is started when the output state of the first or second angle detector 10.11 is reversed. When the value of this counter matches the lunch value set in Pai+,
Timing converter 18 generates an ignition signal and connects ignition circuit 1
1, and the microcomputer 20 determines the ignition coil t1. ignite the engine at the correct ignition timing. In this way, in this embodiment, the engine's steady operating condition fcM k determination 1-1 In the steady state, the correction value that gives the knock limit ignition timing of each cylinder is stored at the address corresponding to the engine operating condition on the learning map. Sequential correction values for individual cylinders with knocking signals memorized and detected every time ignition? Create (2
By correcting the reference ignition timing for each cylinder using this sequential correction value and the stored correction value, it is possible to control each cylinder to the ignition timing of the individual knock limit. On the other hand, updating of the memory correction value is prohibited in the transient operating state of the engine17, and the ignition timing of each cylinder is corrected using the correction value that has already been set under the standard ignition timing under steady state conditions. Even if the state changes, the ignition timing of each cylinder is controlled to the average ignition timing of the knock limits of each cylinder in the operating state after the change. In other words, since only the variation in the knock limit between cylinders is corrected using the sequential correction value created by the knock signal,
Ignition timing feedback control has very good responsiveness. Moreover, since the sequential correction value for each cylinder only needs to correct the variation from the average in the ignition timing that gives the knock limit for each cylinder, the control range is narrow, that is, a wide dynamic range is not required. It is possible to improve control accuracy. In addition, since the correction value on the learning map and the sequential correction value for each cylinder can take values of both positive and negative polarity, the ignition timing can be controlled to the advanced side beyond the standard ignition timing. ,
Even if the standard ignition timing is set to the retard side than the knock limit ignition timing, the memory correction value is updated in the advance direction.
It is possible to operate each cylinder at the knock limit ignition timing over all operating conditions. In this embodiment, when updating the correction value, the update amount of the correction value is created by simply arithmetic averaging the sequential correction values of each cylinder. The update amount may be created using a method such as weighting and averaging depending on the value and polarity, and all stored correction values may be updated. Further, in this embodiment, the cylinders are identified based on the output information of the two angle detectors, but the method is not limited to this method. For example, a detection means for identifying a reference ignition cylinder may be provided to sequentially count the ignitions. Even if there is a method for identifying cylinders, the essence of the present invention is not affected in any way. [Effects of the Invention] As described above, according to the present invention, the standard ignition timing of the engine is set in advance in accordance with each operating state, and the actual knock limit of each cylinder is calculated from this standard ignition timing. The difference in the ignition timing case is determined by a knocking signal, and the average value of this difference is stored as a correction value in a readable/writeable memory corresponding to each operating state of each cylinder of the engine at a predetermined period. It absorbs variations in the ignition timing of the knock limit due to variations, seasonal changes, secular changes, etc., and completely suppresses knocking that occurs in a short period of time with a slight sequential correction amount using the knocking signal. By doing so, non-king suppression can be performed with high precision through ignition timing control.In addition, even if the operating condition of the engine changes, the ignition timing of each cylinder is quickly controlled to the average ignition timing of the knock limit of each cylinder, and transient This prevents the occurrence of large knocks and deterioration of engine performance due to transient retardation. To Mao et al.
Since the standard ignition timing can be corrected to the advanced side, even in operating modes where the standard ignition timing is set to the retarded side with respect to the knock limit ignition timing, each cylinder can be adjusted to the standard ignition timing. On the other hand, while the actual controlled ignition timing is controlled to the advanced side, feedback control can be performed individually using the knocking signal. Therefore, over all operating conditions, each cylinder is tightly controlled by the optimum ignition timing at the knock limit, and there is no longer a need to set the reference ignition timing on the advanced side with respect to the ignition timing at the knock limit. For example, by setting the reference ignition timing with the center value of the knock limit of each cylinder as the target, it is possible to prevent the occurrence of large knocking at the start of control due to the reference ignition timing advancing too much. 4. Brief explanation of the drawings Figure 1 is a block diagram showing the general configuration of the device of the present invention, Figure 2 is a block diagram showing the general configuration of the device of the present invention.
The figure is a block diagram showing one embodiment of the device of the present invention, Figure 3 is a waveform diagram of the output of the angle detector shown in Figure 2, and Figure 4 is a waveform diagram of the output of the angle detector shown in Figure 2.
3 is a flowchart of the operation of the microcomputer shown in the figure. 1... Rotation speed detection means, 2... Load detection means, 3.
. . . Reference control value generation means, 4. . . Cylinder identification means, 5.
Knock detection means, 6 Memory means, 7 Correction value calculation means, 8 Restriction value calculation means, 9 Ignition means. Agent, Masuo Oiwa Figure 3. 7o,' + 3 4 '2 1 3 4 2

Claims (1)

[Claims] A 9-stage knocking detector that detects engine knocking,
an operating state sensor for detecting the operating state of the engine; means for generating a reference control value that provides a standard ignition timing characteristic for each operating state of the engine; and cylinder identification means for identifying the ignition cylinder of the engine. means for generating a sequential correction value for ignition timing based on the output of the knock detection means for each cylinder identified by the cylinder identification means; and the sequential correction value for each cylinder in each operating state of the engine. a memory means for updating and storing the corrected control value obtained by calculating the above at a predetermined cycle at an address corresponding to each operating state of the engine, and reading out the stored value at the corresponding address based on the detection output of the operating state sensor; control value calculation means for calculating the read memory value and the sequential correction value for the cylinder to generate the correction control value for the cylinder; and control value calculation means for calculating the correction control value for the cylinder; An engine ignition timing control device comprising: determining means for determining the ignition timing of each cylinder based on the control value determined by the engine.