JPS59126073A - Ignition timing control device for engine - Google Patents

Abstract

PURPOSE:To improve the combustion characteristics and the output characteristics of the engine by a method wherein the amount of spark delay, capable of obtaining the maximum engine output without generating knocking, is obtained to set a proper ignition timing by correcting the basic ignition timing of the engine based on the amount of spark delay. CONSTITUTION:Upon operating engine, the basic ignition timing, read out of an ROM11, is corrected properly in accordance with the operating condition of the engine based on the outputs of a crank angle sensor 5 and a vacuum sensor 6 in a control circuit 10 to determine the actual ignition timing. At this time, when the generation of knocking is decided from the output of a vibration sensor 7, the amount of delay spark and the frequency of knock, which are set at the previous time, are read out of a table in which the generating frequency of knock in respective operating zone in an RAM12 and the amount of delay spark in the same zone are written while a delay spark constant is added to the amount of delay spark and a predetermined number is added to the frequency of knock to renew said table in accordance with these values. The basic ignition timing is controlled so as to be corrected by the amount of spark delay near the bend of a knock frequency characteristic.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ignition timing control device for an engine that controls ignition timing depending on the occurrence of knocking.

As a conventional example of an ignition timing control device for this type of engine, the one shown in Japanese Patent Publication No. 3;4/--/Otsu No. 203.2 is known. The device detects all engine vibrations above a certain level as knocking vibrations, even though engine vibrations include knocking vibrations and non-knocking vibrations due to the nozzle. If the value is larger, the ignition timing is delayed,
If the ignition timing is smaller than the reference value, the ignition timing is advanced, so even if no knocking is actually occurring, the system will detect nozzle vibration above a certain level as knocking. As a result, there is a problem in that the ignition timing is unnecessarily retarded, resulting in a loss of engine output.

The present invention addresses the problems of conventional engine ignition timing control devices as described above, and provides an engine that improves the combustion characteristics and output characteristics of the engine by preventing unnecessary ignition timing retardation. This device was developed for the purpose of providing an ignition timing control device, which includes a vibration sensor that outputs a signal corresponding to engine vibration, an operating state sensor that detects the operating state of the engine, and a basic ignition timing control device for each engine operating state. a first storage device that stores the timing in advance; a second storage device that stores the frequency of occurrence of engine vibration of a predetermined level or higher relative to the ignition timing for each engine operating state; and an engine that is detected by an operating state sensor. A basic ignition timing corresponding to the operating state of the engine is determined from the first storage device, the basic ignition timing is corrected according to the output of the vibration sensor, ignition is performed based on the corrected ignition timing, and at this time, The generated engine vibrations of a predetermined level or higher are stored in the second storage device as an occurrence frequency, and after the engine vibration occurrence frequency characteristic of the predetermined level or higher with respect to the ignition timing created in the second storage device reaches a predetermined accuracy. The present invention is characterized by comprising a control circuit that operates to cause ignition to occur at an ignition timing near the bend υ where the frequency of occurrence is balanced with respect to the ignition timing.

Hereinafter, the engine ignition timing control device of the present invention will be explained based on the embodiment shown in the illustrated drawings. First, before explaining the configuration of this ignition timing control device, the technical background on which the present invention is based will be explained. Accordingly, this invention has discovered that there are two causes of engine vibration that can be directly detected from the engine by a vibration sensor. This invention was made based on the fact that in order to control the timing, it is necessary to clearly distinguish between knocking vibration and noise vibration and control the ignition timing in accordance with the knocking vibration. While searching for a way to distinguish between vibration and noise vibration, we discovered that knocking vibration is caused by premature ignition timing, and that it can be reliably reduced by delaying the ignition timing (increasing the amount of ignition retardation). , focused on the fact that noise vibration is a phenomenon unrelated to ignition timing, and therefore cannot be reduced no matter how much the ignition timing is retarded. We came to the conclusion that it should be possible to clearly distinguish between knocking vibration and other noise vibrations by investigating the frequency of occurrence of engine vibrations greater than 100 mV.Furthermore, in order to quantitatively understand this, we should be able to determine the ignition timing retardation. The amount of angle is on the horizontal axis,
Taking the frequency (probability) of occurrence of engine vibration above a certain level as the vertical axis, we investigated the frequency of occurrence of engine vibration with respect to changes in the amount of retardation in each operating state. As shown in Figure 2, the amount of retardation gradually increases from 0. The frequency of occurrence of engine vibration gradually decreases as the amount of retardation increases, and after reaching a certain amount of retardation θK, the frequency of occurrence of engine vibration becomes parallel to the horizontal axis and does not change at all, no matter how much the amount of retardation is increased. It was possible to obtain the characteristic diagram 1 for each operating state.

From this characteristic diagram 1, it can be seen that in a region where the retardation amount is smaller than the retardation amount θ corresponding to the bending point A of this characteristic diagram 1, as the retardation amount is increased, the engine vibration above a certain level is Since the frequency of occurrence has decreased, this means that L-knocking vibration was occurring in this region (
This region is referred to as the knocking generation region), and in the region where the retardation amount is larger than the retardation amount θ corresponding to this bending point A, the frequency of occurrence of engine vibration does not change even if the retardation amount is increased. Therefore, it can be seen that knocking vibration does not occur in this region, and only noise vibration occurs (this region is called the knocking non-occurring region). Therefore, in order to maximize the engine output without causing knocking, draw a characteristic diagram 1 as shown in Figure 2 corresponding to each operating state of the engine, find the bending point A, and then ignite. This means that the ignition position should always be set to the minimum retard angle θ at which knocking vibration does not occur.

The ignition timing control device of the present invention is based on the above-mentioned technical background and is designed to always perform ignition at the ignition timing of the minimum retarded needle that does not cause firing. In order to obtain this, learning control of ignition timing is performed.

Hereinafter, an ignition timing control device for an engine according to the present invention will be described using an ignition timing control device z installed in an automobile engine shown in FIG. 1 as an example.
tZ is a crank angle sensor J that detects the crank angle of the engine, a negative pressure sensor B that detects the negative pressure in the intake pipe 2, and a sensor B that detects engine vibration on the engine L side. A vibration sensor 7 is provided. Of these sensors, the crank angle sensor j and the negative pressure sensor B constitute an operating state sensor that detects the operating state of the engine. Based on the signals inputted from each sensor, the control circuit 10 controls the ignition coil 1 to control the ignition timing of the spark plugs 3, 3, . . . . Further, as described above, this ignition timing control device 2 is configured to perform ignition at an ignition timing near the retard amount corresponding to the bending point A of the characteristic diagram 1 (FIG. 2) in each operating state. In order to obtain the characteristic diagram 1 for each operating state, λ storage devices are used, as shown in FIG.
Basic ignition timing θB corresponding to N and manifold negative pressure P
As shown in Figure 7, the correlation between the amount of retardation and the frequency of knocking (characteristic diagram 1) is shown in Figure 7. A second storage device (RAM)/2 for reading and writing is provided with a second storage device (RAM)/2 for both writing and reading, which has a knock frequency table in which a knock frequency table is written corresponding to the operating state of the engine as shown in FIG. By updating and setting the values of each table in the knock frequency table to appropriate values each time, the characteristic diagram is finally drawn and its bending point A is found, and after finding the bending point A, , ignition is performed at an ignition timing with a retard amount corresponding to this bending point A.

Below, the procedure for setting the appropriate ignition timing will be explained with reference to the control flowchart shown in Fig. The region is determined and the ignition timing corresponding to this operating region is set. That is, as shown in Fig. g, the crank angle of the previous day B T D C! 70° time 1. And this time 00 o'clock time t of BTDO! Calculate the rotation period T, (= t, -t,) of the crank from (sign 2/
), the current rotation speed N is calculated from this rotation period T, sign 22), and the manifold negative pressure P (sign 2) detected by this rotation speed N and negative pressure sensor B.
3) Determine the current engine operating range from code 2.
The basic ignition timing θnt corresponding to the current operating range is read from the basic ignition timing map of the Il-χ first storage device // (
code, 2j). For example, if the manifold negative pressure is pm.

~The foot is within the range of the rod and the engine speed is Nn-1~N
If it is within the range of n, the basic ignition timing is θc1. becomes. Next, from this basic ignition timing θB and the retardation amount θK previously set by the control procedure as described later (if this control is the first time, this retardation amount θ will be 0), the current Calculate the ignition timing θ (=θ + θB) (sign, i!O).

Once the ignition timing θ is determined, the ignition time corresponding to this ignition timing is calculated (code, 27..2g), ignition is performed at this ignition time (code, 29), and after ignition, the next ignition Calculate the start time of energization to the ignition coil in preparation for 30, . 3/), energization is started at a predetermined energization start time (symbol 3.2).

When the ignition plug 3 is ignited and combustion takes place in the cylinder, engine vibration occurs, and vibrations above a certain level are detected by the vibration sensor 7, and the knock intensity IK is determined from the output of the vibration sensor 7. is read (code 33), and it is determined whether or not a knock has occurred (code 3).
'l-). That is, when the knock intensity IK-0, it is determined that no knock has occurred, and conversely, when IK > (7), it is determined that a knock has occurred.The presence or absence of knock occurrence is confirmed by the knock determination. Next, a table (
The retardation amount θ and the knock frequency Cl of each table of the knock frequency table (FIG. 7) having Replace it with Ct and gradually draw the characteristic diagram 1 (Figure 2). That is, when it is determined that a knock has occurred as a result of the knock determination, the table corresponding to the operating state of the knock frequency table, for example, TtLbla, ml, is used to determine the previously set retardation amount θ and the retardation amount θK. Knock frequency C
Read L and first set 0.01 to the previous knock frequency 04.
is added to obtain a new knock frequency C7 (symbol 3j). In other words, if knocking occurs 17 times, the knock frequency value is set to 7.
In this case, the knock frequency Cl is oS
ct.

Since the value must be ≦/, it is checked whether CL>/ (code 3 O), and if OL> /, it is forcibly set to OL=/ (code 37). Furthermore, since knock occurred at the previously set retardation amount θK, in order to eliminate this knock, it is necessary to increase the retardation amount according to the value of the knock intensity IK. Correction to the retardation amount θK -IK to the retardation amount (K: retardation constant)
is added to the new retard amount θ (symbol 3J).

On the other hand, when it is determined that there is no knock, the new knock frequency C7 is subtracted by 0.0/ from the previous knock frequency Ct by the operation that is completely opposite to the operation when it is determined that there is a knock described above. The new retard amount θK is delayed from the previous retard amount θK by a constant value ΔθA (one ΔθA for θ) (sign≠0).
) Set each.

Next, the new retard amount θK obtained as described above is corrected using the table Tab(n, wh) corresponding to the operating range of the knock frequency table updated as described above. Based on this retardation amount θ, it is determined whether the i-minock generation region or the non-knock occurrence region (in other words, which side of the bending point A of the characteristic curve l is located), and if necessary, the retardation amount is determined. Amount OK
Correct. That is, the knock frequency CL (updated value) corresponding to the retard amount θK of the predetermined table Tab (n, m) of the knock frequency table corresponding to the driving region and the retard amount θ are larger by 7 categories. Calculate the difference △C(CLCl+1) from the knock frequency C6+1 corresponding to +1 with the sign l
/l/), check whether △C>O (symbol 4L2>(
(See Figure 3).

If △C>O, the value of this retard amount θ is the characteristic diagram Lt
Since it is located closer to the knocking occurrence area than D bending point A, there is no need for correction, and the knocking frequency (34 to 7
- AyTab (write to rL, ml. Conversely, △0≦
If it is 0, the retard amount θ is at the bending point A of the characteristic diagram 1.
On the non-knocking area side, it can be seen that the engine vibration that has just occurred is due to the nozzle/L/vibration. Therefore, it is necessary to reduce the retard amount, and the (advanced angle) value (advance angle) obtained by reducing the new retard amount Ox obtained by the knock judgment by a predetermined retard amount ΔθF (one ΔθF for θ) is used as the retard angle flA (h, Table Tab(n,
Write on paulownia (code l1-3). In addition, at this time, the retard amount θ
Since a negative value cannot be small, check whether it is O to 0 (sign ≠≠>, if OVO, leave it as is, or change θy
, if < 0 then = θ.

As a result, the amount of retardation with respect to the basic ignition timing θB is corrected (No. 44 11.j).

As described above, each time the engine is ignited, a knock determination is made on the engine vibration generated at that time, and the knock frequency C6 is updated to the retard amount θ written in the table Tab(n-) corresponding to each operating region. By setting the retard amount θ
The value of can be gradually focused to the retard amount corresponding to the bending point A in the characteristic diagram 1. Therefore, as the retardation amount θ and the number of flops of the knock frequency C7 are increased, the accuracy of the characteristic diagram 1 improves, and the bending point A increases according to the sharpness.
The location will become clear. However, in this embodiment, if the number of flops seems to have reached a predetermined value or more based on the driving time or vehicle mileage, etc., the position of the bending point A of the characteristic diagram 1 in each driving region is clearly determined. After that, the appropriate retardation amount θK (i.e., the bending point Immediately read out the retardation amount corresponding to A) from the table of the predetermined operation area of the knock frequency table, and set the read retardation amount θ.
Basic ignition timing θ read from basic ignition timing map
I am trying to set all the appropriate ignition timing from B.

By doing so, it becomes possible to operate the engine throughout the entire operating range at an ignition timing that does not cause knocking and provides maximum engine output.

Next, to explain the present invention in detail, the engine ignition timing control device of the present invention determines, by learning, the probability of occurrence of knocking vibration and noise vibration in each operating region of the engine, and the characteristics of the amount of retardation of ignition timing. From this characteristic, the amount of retardation corresponding to the boundary between the knocking region where knocking occurs and the non-knocking region where knocking does not occur, in other words, the amount of φ that does not cause knocking.
We find the retard angle that can obtain the maximum engine output, and use this retard amount to correct the basic ignition timing of the engine and set the appropriate ignition timing, so if the engine vibration exceeds a certain level, Conventional engine ignition timing control devices detect noise vibrations as knocking vibrations and control the amount of retardation of the engine's ignition timing accordingly. This has the effect that the combustion characteristics and output characteristics of the engine can be improved accordingly without causing any deterioration.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of an engine ignition timing control device according to an embodiment of the present invention; FIG. M2 and FIG. 3 are characteristic diagrams showing the correlation between the amount of retardation and the frequency of knocking and loud noise;
Figure ≠ is an ignition timing control flowchart, Figure 5 is a basic ignition timing map, Figure 6 is a knock frequency table, Figure 7 is a table within the knock frequency table, Figure 5 is a diagram showing crank angle and ignition coil energization timing. It is a line diagram showing a relative relationship. /...1" Engine j ・11@Crank angle sensor 2...Negative pressure sensor 7...Vibration sensor 10...Control circuit//...First storage device/ ------, 2nd storage device 2nd

Claims (1)

[Claims] l. A vibration sensor that outputs a signal corresponding to engine vibration; an operating state sensor that detects the operating state of the engine; a seventh storage device that stores in advance the basic ignition timing for each engine operating state; a second storage device that stores the frequency of occurrence of engine vibration of a predetermined level or higher with respect to the ignition timing; and a first storage device that stores the basic ignition timing corresponding to the engine operating state detected by the operating state sensor. The basic ignition timing is corrected according to the output of the vibration sensor, and ignition is performed based on the corrected ignition timing, and engine vibration of a predetermined level or higher occurring at this time is set as the frequency of occurrence in the first memory. After the engine vibration occurrence frequency characteristic of a predetermined level or higher with respect to the ignition timing created in the second storage device reaches a predetermined accuracy, a bending pattern is created in which the occurrence frequency is balanced with respect to the ignition timing. An ignition timing control device for an engine, comprising a control circuit that operates to cause ignition to start at a nearby ignition timing.