JPH076486B2 - Ignition timing control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition timing control device for an automobile gasoline engine or the like, and more particularly, to control ignition timing correction 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 an electric ignition type internal combustion engine such as a gasoline engine,
Generally, it is desirable in terms of performance to advance the ignition timing to the limit at which knocking occurs.

However, due to slight changes in engine characteristics and variations in fuel quality, it is not always possible to obtain stable operation if the limit of occurrence of knocking is set in advance, causing knocking or reducing performance. Or

However, if knocking occurs, the life of the engine will be shortened, and in extreme cases, the engine will be destroyed.
This has to be suppressed, which is a particular problem for turbocharged engines.

Therefore, a so-called knocking control system has come to be used, which detects occurrence of knocking, controls the ignition timing based on the detected feedback, and enables the engine to operate at the limit of occurrence of knocking at all times.

Therefore, such a notk
The principle of knock detection in a control system (known as knock) will be described below with reference to FIG. Note that such a knock control system is disclosed in, for example, Japanese Patent Laid-Open No.
-217773.

Now, referring to FIG. 4, the knock sensor 1 is a kind of acceleration detector and is attached to an engine block or the like, and detects the vibration of the engine to generate an output a. Thus, the engine vibration is distributed over a fairly wide range of frequency components, as shown in the lower left of the figure.

Therefore, the output a is input to the band pass filter 2 to extract the frequency component (which is said to be 6 to 8 KHz) peculiar to the knock to obtain the output b.

On the one hand, this output b is supplied to the amplifier 3 to become a SIG signal of a predetermined level, and on the other hand, it passes through the half-wave rectifier 4 and the average value circuit 5 to become a back ground level signal BGL consisting of a DC component.

Then, these signals SIG and BGL are input to the comparator 6, and only the portion where the level of the SIG signal exceeds the level of the BGL signal is taken out as a knock signal. Therefore, this knock signal is provided as a pulse, and the number of pulses in the series will represent the intensity level of the knock.

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

First, a knock counter for counting knock signals is prepared, and this counter is cleared by a signal REF generated each time the crankshaft of the engine 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 strength level of the knock.

Therefore, every time the count value of this knock counter is cleared by the signal REF, it is taken in immediately before that, and a predetermined ignition timing retard amount (this is called proportional θ _R ) is read by a table or the like according to this count value. Calculated, basic ignition timing θ
(N, L) to obtain the ignition timing θ _ING .

On the other hand, after the proportional amount θ _R is given to the ignition timing in this way, it is given a predetermined ratio at the basic ignition timing θ (N, L)
An ignition timing return amount (which is referred to as an integral component θ ₁ ) that changes depending on the timing is provided for returning to.

Therefore, according to this system, when a knock occurs,
The ignition timing is retarded in accordance with the intensity level, and the knock can be effectively suppressed and the engine performance can be sufficiently exhibited. Here, θ _KN = (θ _R + θ _I ).

By the way, it is well known that notching of gasoline engines and the like greatly depends on the octane number of fuel, and in general, notking is likely to occur in regular gasoline and is less likely to occur in high octane gasoline called high octane or supermarket. It is said that. That is, it is necessary to determine the engine performance in consideration of the occurrence of knocking due to the property of fuel.

Therefore, due to these restrictions, the conventional engine control device assumes various constant gasoline properties, and sets various data such as ignition timing data on the assumption that the gasoline properties are low. If it is shared, the above-mentioned assumptions will be exceeded, and the performance or durability of the engine will be adversely affected.Furthermore, there will be a limit to the force majeure factor, for example, the correction operation against changes over time. There is a problem that it is difficult to properly maintain the matched ignition timing.

[Object of the Invention]

The object of the present invention is to address the above-mentioned problems of the prior art,
It is an object of the present invention to provide an ignition timing control device capable of sufficiently following a change in the anti-knock property of fuel and a change over time that appears in the characteristics of an engine or the like and always obtaining an accurate knock control.

[Outline of Invention]

To achieve this object, according to the present invention, the ignition timing is controlled by searching a table, and different data is written in advance as the table in response to changes in fuel anti-knock property and engine characteristics. Is prepared, and one of the plurality of tables is selected according to the frequency of occurrence of knock to perform ignition control.

Example of Invention

Hereinafter, the ignition timing control device according to the present invention will be described in detail with reference to the illustrated embodiment.

FIG. 3 shows an embodiment of the present invention. In the figure, 10 is an engine, 20 is a control device, 22 is a microcomputer (microcomputer), 24 is a knock detector, 30 is an ignition coil, 40 is an ignition plug, and 50 is an ignition plug. It is a sensor group. The sensor group 50 is composed of sensors for fetching various data necessary for controlling the engine such as the engine speed, the intake air flow rate, the cooling water temperature, and the idle switch. The knock sensor 1 is the same as in the case of FIG.

FIG. 1 shows an embodiment of a control device 20, which comprises a microcomputer 22 having an ignition timing table A101, B102, a timer 103, an ignition register 104, a knock number counter 105, etc.
Ignition timing control for the ignition coil 30 by calculation processing of information from the sensor group 50 including other engine information including a knock signal which is an input signal from the knock detection unit 24, a rotation angle signal, a throttle opening signal (not shown), etc. It is designed to output a signal.

Next, the operation of this embodiment will be described with reference to the flow chart of FIG.

The processing routine according to this flow chart is started by the REF signal (rotational angle signal of the sensor group 50) described in FIG. 5, and as a result, in the case of a four-cylinder engine, two revolutions occur every time the engine makes one revolution. This routine is executed once. When this routine is entered, the number of times of occurrence of knock is first counted in step S1 (hereinafter step is omitted), and it is determined in S2 whether or not to select a table. The determination condition at this time may be a desired ignition cycle (for example, 400 ignition cycles) or a desired time (for example, 1 minute).

When the result in S2 is NO, the process goes through S5, and the ignition timing table remains the same as the previous time.

On the other hand, if the result in S2 is YES, proceed to S3, reset the knock occurrence counter, and then in S4, the value N _X of this counter is between the preset minimum value N _L and maximum value N _H. Or not. The minimum values N _L and N _H at this time are, for example, N _L = 3 and N _H = 5.

First, when the result in S4 is N _L N _X N _H , the process goes through S5, and the ignition timing table remains the same as before.

On the other hand, if the result in S4 is N _H <N _X , the gasoline that is prone to knocking (regular gasoline) is judged, and at this time, it passes S7 and the data content corresponds to the gasoline that is prone to knocking. The ignition timing table A is selected, this value is set in the ignition register in S8, and this routine is exited.

In addition, when the result in S4 is N _L > N _X , it is determined that knocking is not likely to occur (high-octane or super gasoline) and the process in S6 is performed, and the data content corresponds to gasoline where knocking is unlikely to occur. Ignition timing table B
Is selected, and the processing after S8 is executed.

Therefore, according to this embodiment, the base ignition timing table is selected so that the frequency of occurrence of knocks always falls within a certain range, and even if the quality of gasoline changes, the effect of this is canceled out. Therefore, the engine state can always be maintained at an appropriate ignition timing.

Although not particularly described in the above embodiment, it goes without saying that S5 is one of the ignition timing tables A and B when there are two ignition timing tables described above.
Of course, even in the case of N pieces, it is possible to select every moment by the same processing.

〔The invention's effect〕

As described above, according to the present invention, since the ignition timing is always automatically corrected to the optimum value, it is possible to eliminate the problems of the prior art and of course to cope with the change in gasoline quality. That is, it is possible to easily provide an ignition timing control device that has the same effect with respect to the change over time of the engine body or the knock sensor, and can sufficiently exhibit its performance without causing damage to the engine. .

Further, according to the present invention, by storing a plurality of ignition timing tables corresponding to the octane number of gasoline in the same control device, it is possible to use a common ignition timing control device regardless of the difference in vehicle type and designated gasoline. There is.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an ignition timing control device according to the present invention, and FIG. 2 is a flow chart for explaining the operation.
FIG. 3 is a block diagram showing an example of an engine system to which the present invention is applied, FIG. 4 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, 24 ... knock detection part, 101 ... ignition timing table A, 102 ... ignition timing table B (C to N), 103 ... timer, 104 …… Ignition register, 105 …… Knock counter.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Aiichi Uehara 2520 Takaba, Katsuta City, Ibaraki Prefecture Sawa Plant, Hitachi, Ltd. (56) References JP-A-60-104775 (JP, A) JP 56-48700 (JP, B1)

Claims (1)

[Claims] 1. In an ignition timing control device of a method of detecting an operating state of an internal combustion engine and determining an ignition timing by searching an ignition timing table based on the detection result, the number of knocks generated in the engine reaches a predetermined value. Table selection condition determining means for determining whether or not, and the knocking occurrence frequency N _X is set to a minimum value N _L and a maximum value, provided that the determination result by the table selection condition determining means is YES. Knock frequency determination means for determining the relationship with the value N _H , and multiple ignition timing tables with different data contents for gasoline that is prone to knocking and gasoline that is hard to knock the door is provided, when the determination result by the knock frequency determination means becomes N _L <N _X, the data content corresponds to gasoline knocking is likely to occur Select ignition timing table A controls the ignition timing are, when the determination result by the knock frequency determination means becomes N _L <N _X is ignition timing data content corresponds to hard gasoline to knocking The table B (CN) is selected to control the ignition timing, and when the determination result by the table selection condition determining means becomes NO and when the determination result by the knock frequency determining means is
When N _L ≦ N _X N _H , the ignition timing control device is configured to control the ignition timing by using the previously selected ignition timing table as it is.