JPS6258057A - Ignition timing control device - Google Patents

Abstract

PURPOSE:To accurately control the knocking at all times, by selecting one of plural ignition tables according to the generation frequency of the knocking in deciding an ignition timing by the retrieval of the ignition timing tables on the basis of detection results of engine operational condition. CONSTITUTION:The generation of knocking during operation of an engine is detected by a knock detection means 24 according to an output from a knock sensor 1, an a knock generation frequency is counted by a microcomputer 22 according to a detection output from the knock detection means. Then, a knock generation counter is reset at every predetermined ignition cycle, and it is determined whether or not a counter value NX at this time lies between a minimum value NL and a maximum value NH. If NH<NX, it is determined that the gasoline tends to generate the knocking, and therefore an ignition timing table A is selected. If NL<NX, it is determined that the gasoline is hard to generate the knocking, and therefore an ignition timing table B is selected. Then, either the table A or B is retrieved according to the engine operational condition to decide an ignition timing.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an ignition timing control device for an automobile gasoline engine, etc., and particularly to a control device for correcting the ignition timing by determining the occurrence of knock based on the output signal of a knock sensor. The present invention relates to an ignition timing control device suitable for performing.

[Background of the invention]

In internal combustion engines with electric ignition, such as gasoline engines,
Generally speaking, it is desirable for performance to advance the ignition timing to the limit where knocking occurs.

However, due to small changes in engine characteristics and variations in fuel quality, setting a knocking limit in advance does not always provide stable operation, which may result in knocking or performance deterioration. bring something.

However, if knocking occurs, it will shorten the life of the engine, and in extreme cases it may even destroy the engine, so please avoid it as much as possible.
This must be suppressed, and this is a particular problem in the case of turbocharged engines.Therefore, the occurrence of knocking is detected and the ignition timing is controlled as a feedback to ensure that the engine is always operated at the knocking limit. So-called knock control systems have come into use.

Therefore, this kind of knocking (knocking is referred to as
The principle of knock detection in the control system (referred to as knock) will be explained below with reference to FIG. By the way, such a knock? The tt control system is disclosed in, for example, Japanese Unexamined Patent Publication No. 58-217773.

Now, in FIG. 4, a knock sensor 1 is a part of an acceleration detector, which is attached to an engine block or the like, and detects engine vibrations and generates an output a. As shown in the lower left of the figure, engine vibration is distributed over a fairly wide range of frequency components.

Therefore, input this output a to the bandpass filter 2,
A frequency component (said to be 6 to 8 kHz) specific to knocking is extracted to obtain an output signal.

This output signal is supplied to an amplifier 3 on the one hand and becomes an SIQ signal of a predetermined level, and on the other hand, it is passed through a hand rectifier 4 and an average value circuit 5 to become a background level signal BGL consisting of a DC component.

These signals SIG and BGL are input to a comparator 6, and only the portion where the level of the SIG signal exceeds the level of the BGL signal is extracted as a knock signal. Therefore, this knock signal is given as pulses, and the number of pulses in the series represents the intensity level of the knock.

Next, ignition timing control for knock control using this knock signal will be explained with reference to FIG.

First, a knock counter that counts knock signals is prepared, and this counter is cleared by a signal R]liF that is generated each time the engine crankshaft reaches a predetermined rotation angle position (.

Then, the count value of this knock counter immediately before it is cleared represents the number of pulses of the knock signal at that time, that is, the knock intensity level.

Therefore, the count value of this knock counter is sent to the signal REF.
Every time you clear it, import it just before that.

In accordance with this count value, a predetermined ignition timing retard angle i (referred to as a proportional portion θ8) is determined from a table or the like, and the basic ignition timing θ(N,L)K is provided to obtain an ignition timing θ1116.

On the other hand, after the proportional portion θ is given to the ignition timing in this way, it is converted to the basic ignition timing θ(N,
L) An ignition timing control value (this is called an integral θ) that changes by 1 per hour for returning K is given.

Therefore, according to this system, when a knock occurs,
The ignition timing is retarded in accordance with the intensity level, effectively suppressing knock and fully demonstrating engine performance. Note that here θ, N=(θ8+θ,).

By the way, it is well known that knocking in gasoline engines is greatly affected by the octane number of the fuel, and in general, % knocking is more likely to occur with regular gasoline and less likely to occur with high-octane gasoline called high-octane or super gasoline. has been done. In other words, engine performance must be determined with consideration given to the occurrence of knocking due to the properties of the fuel.

Therefore, due to these constraints, conventional engine control devices assume certain gasoline properties and set various data such as ignition timing data based on that assumption.

If high octane gasoline is used in common, the above-mentioned assumption will be violated and there will be an unfavorable effect on engine performance or attackability, and furthermore, there will be unavoidable factors.

For example, there are seven limits to correction operations for changes over time.

For this reason, there are five problems in that it is difficult to always maintain an appropriate ignition timing that matches the characteristics of the engine.

[Purpose of the invention]

The purpose of the present invention is to address the problems of the prior art mentioned above,
It can fully follow changes in the anti-knock properties of fuel and changes over time that appear in engine characteristics.

To provide a 5K ignition timing control device that can always obtain accurate knock control.

[Summary of the invention]

In order to achieve this object, the present invention controls the ignition timing by searching a table.

As a cono table, we select multiple tables that contain different data in advance in response to changes in fuel anti-knock properties and engine characteristics, and select one of these tables depending on the frequency of knock occurrence. Select and ignite 11tl
The feature is that l tal is performed.

[Embodiments of the invention]

The ignition timing control device according to the present invention will be explained below.

This will be explained in detail with reference to the illustrated embodiment.

FIG. 3 shows an embodiment of the present invention. In the figure, 10 is an engine, KA is a control device, ρ is a microcomputer, Sae is a knock detection unit, 30 is an ignition coil, 40 is a spark plug, and 50 is a A group of sensors.

Note that this sensor #blade consists of sensors for capturing various data necessary for engine control, such as engine rotation speed, intake air flow rate, cooling water temperature, and idle switch. Further, the knock sensor 1 is the same as that shown in FIG.

FIG. 1 shows an embodiment of the control device W, which consists of four microcomputers with built-in ignition timing tables A 101 , B 102 , a timer 103 , an ignition register 104 , and a knock count counter 105 . Information from a sensor group (source) consisting of a knock signal, which is an input signal, and other engine information including a rotation angle number 1, a throttle rotation signal (not shown), etc. is calculated and processed to determine the ignition timing side (source) for the ignition coil blade. ) signal is output.

Next, the operation of this embodiment will be explained with reference to the flowchart of FIG.

The processing routine according to this flowchart is the rotation angle signal (rotation angle signal between the R and EF multiplied signal sensor groups) explained in FIG.
As a result, in the case of a 4-cylinder engine, it is executed twice every revolution of the engine, and when entering this routine, the first step is step S1 (hereinafter steps will be omitted).
The number of knock occurrences is counted at step S2, and it is determined whether or not to perform table selection at step S2. The determination condition at this time may be a desired ignition cycle (for example, 400 ignition coil cycles) or every desired time (for example, 1 minute).

When the result in S2 is NO, 85 is passed and the ignition timing table is kept the same as the previous time.

On the other hand, if the result in S2 is YES, the process advances to 83 and after resetting the knock occurrence counter, the value Nx of this counter is changed to the preset minimum value NL and maximum value N! Determine whether it is between I. The minimum value N at this time
As L and NM, for example, NL=3. It is called NH-4.

First, when the result in S4 is NL<Nx<NM, the process goes to S5, and the ignition timing table remains the same as the previous one.

On the other hand, if the result in S4 is NH (N), it is determined that the gasoline is likely to cause knocking (regular gasoline), and in this case, go through S7, select ignition timing table A, and set this value at 58vc. to the ignition register and exit this routine.

In addition, when the result in 84 is N, )N, it is determined that the gasoline is less likely to cause knocking (high octane or super gasoline), and the process of S6 is performed, ignition timing table B is selected, and the process from S8 onwards is performed. Execute.

Therefore, according to this embodiment, the base ignition timing table is selected so that the frequency of occurrence of knock (0) always falls within a certain range, and even if the quality of gasoline changes, the effect of this is negated. This makes it possible to maintain the engine condition with precise ignition timing at all times.

Although not specifically described in one or more embodiments.

It goes without saying that if there are two ignition timing tables as described above, S5 will be either ignition timing table A or B, and even if there are N ignition timing tables, the selection can be made moment by moment using the same process.

〔Effect of the invention〕

As explained above, according to the present invention, the ignition timing is automatically corrected to the optimum value at all times (therefore, the problems of the conventional technology can be eliminated, and it is also possible to cope with changes in gasoline quality. The main body of the institution.

Alternatively, it is possible to easily provide an ignition timing control device that has a similar effect on changes in the knock sensor over time and can fully demonstrate its performance without causing damage to one engine.

Furthermore, according to the present invention, by storing multiple ignition timing tables corresponding to the octane number of gasoline in the same control device, the ignition timing control device can be shared regardless of the difference in vehicle type or specified gasoline. There is.

[Brief explanation of drawings]

Figure 1 is a block diagram showing an embodiment of the ignition timing control device according to the present invention, Figure 8g2 is a flowchart for explaining operation, Figure 3 is a block diagram showing an example of an engine system to which the present invention is applied, and Figure 4 The figure is an explanatory diagram showing the principle of knock detection, and FIG. 5 is a time chart explaining the knock control operation. 1... Knock sensor, 20... Control device, 22... Microcomputer, Sae... Knock detection section % 101... Ignition timing table A.1
02...Ignition timing table B (C to N), 10
3...Timer, 104...Ignition register. 105...Knock number counter. Agent: Patent Attorney Kenjibe Take (1 other person) Figure 1 Figure 2 Figure 3 Figure 5

Claims (1)

[Claims] 1. Means for detecting knocking occurring in the engine in an ignition timing control device that detects the operating state of the internal combustion engine and determines the ignition timing by searching an ignition timing table based on the detection result. and a plurality of ignition timing tables having different data contents, and the ignition timing is controlled by selecting one of the plurality of ignition timing tables according to the frequency of occurrence of knocking. An ignition timing control device featuring: 2. The ignition timing control device according to claim 1, characterized in that the knocking occurrence frequency is calculated every predetermined ignition cycle. 3. The ignition timing control device according to claim 1, wherein the frequency of occurrence of knocking is calculated at predetermined intervals.