JPS6228313B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ignition timing control device for an internal combustion engine in which the position of a cylinder in a combustion process among the cylinders of an internal combustion engine is determined, and a knocking determination level is changed depending on the position.

The conventional notsking feedback system is
Knocking is detected from the vibration sounds inside the internal combustion engine. When the knocking signal is detected, the ignition timing is retarded by a certain angle, and when the knocking signal is not detected for a certain period of time, the ignition timing is advanced by a certain angle.

Conventional knock feedback systems determine knocking and adjust the ignition timing when the signal generated by the knocking detector becomes larger than the determination level created within the knock feedback system. is delayed.
Generally, a knocking detector attached to the internal combustion engine body detects knocking in many cylinders. However, vibrations generated from cylinders that are physically distant from the detector are harder to detect than vibrations from nearby cylinders, and the detection signal is also smaller. In other words, depending on the position of the cylinder,
The ability to detect knocking is different, which worsens the controllability of ignition timing in distant cylinders. As a result, the ignition timing in the cylinders far from the knocking detector becomes overadvanced, increasing knocking.
This will eventually cause damage to the combustion chamber and deterioration of engine operability.

The present invention has been made in view of the above-mentioned drawbacks of the conventional ignition timing control device, and the present invention improves the knocking judgment level in the knocking feedback system in response to the difference in the signal level generated by the knocking detector depending on the cylinder. By detecting the cylinder in combustion, if the cylinder is far from the knocking detector, the knocking judgment level is lowered, and if the cylinder is close to the knocking detector, the knocking judgment level is raised, thereby improving the knocking detectability by cylinder. An object of the present invention is to provide an ignition timing control device for an internal combustion engine, which corrects variations in the ignition timing of each cylinder, optimally controls the ignition timing of each cylinder, and reduces knocking generated from a combustion chamber in a controlled state.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An ignition timing control device according to the present invention will be described below with reference to the accompanying drawings. Figure 1 shows the first part of the device of the present invention.
FIG. 2 is a block diagram showing an embodiment. Reference numeral 1 denotes a knocking detector made of a piezoelectric element or a power generation element (magnet, coil), which detects vibrations or sound waves of the engine body due to knocking of the internal combustion engine. A combustion cylinder detector 2 detects the position of the cylinder currently in the combustion process of the engine. 3 is a distributor that generates a reference ignition signal. 4 is an ignition device that provides an ignition signal to a spark plug (not shown).
Reference numeral 5 denotes an ignition timing calculation circuit that determines ignition timing according to the operating state of the internal combustion engine based on signals from the knocking detector 1, the combustion cylinder detector 2, and the distributor 3. The ignition timing calculation circuit 5 is further configured as follows. A filter 51 is connected to the knocking detector 1 and removes noise in the detection signal of the knocking detector 1. 52 is a knocking detection circuit which detects the presence or absence of knocking from the signal from which noise has been removed. Reference numeral 53 denotes an up/down counter (hereinafter simply referred to as a U/D counter), which corrects the advance angle based on a detection signal from the knocking detection circuit 52. 54 is a lead angle timer, which provides the U/D counter 53 with the lead angle timing. 55 is a waveform shaping circuit that shapes the detection signal from the combustion cylinder detector 2. Reference numeral 56 denotes a determination level correction circuit, which generates a difference signal between determination levels for each cylinder based on the output signal from the waveform shaping circuit 55. 57 is a waveform shaping circuit connected to the distributor 3, which shapes the waveform of the reference ignition signal from the distributor 3. 58 is a retard calculation circuit, and the waveform shaping circuit 5
The ignition timing is calculated based on the reference ignition signal passed through step 7 and the signal from the U/D counter 53 after the advance angle correction. 59 is a closing angle control circuit, which controls the closing angle of the idaniter 4.

FIG. 2 is a diagram specifically showing the configuration of the combustion cylinder detector 2 and knocking detection circuit 52 in FIG. 1.

The combustion cylinder detector 2 detects the cylinder currently in combustion. For example, in a 4-cylinder internal combustion engine, if the knocking detector 2 is located between the 2nd and 3rd cylinders, the knocking detector 2 will have difficulty detecting the signals from the 1st and 4th cylinders, but will easily detect the signals from the 2nd and 3rd cylinders. Therefore, it is only necessary to create a signal that distinguishes between combustion in cylinders 1 and 4 and cylinders 2 and 3. For this purpose, the combustion cylinder detector 2 is composed of a disk 21 attached to the crankshaft of the internal combustion engine, a light source 22, and a photodetector 23. This disk 21 blocks the light entering the photodetector 23 while the 1st and 4th cylinders are burning due to the rotation of the crankshaft, and blocks the light entering the photodetector 23.
While the cylinder is in combustion, the light from the light source 22 is not blocked. The photodetector 23 generates a voltage corresponding to the amount of incident light (for example, a phototransistor or CDS). In addition, an electromagnetic pickup type can be considered as a combustion cylinder detector.

The knocking detection circuit 52 is configured as follows. Rectifier 521, integrator 522, amplifier 52
3. The adders 524 are connected in series with each other and connected to one end of the comparator 527. The output of the rectifier 521 is connected to the other end of the comparator 527. An adder 525 is further connected to the adder 524 and adds signals from a voltage conversion circuit 561 and an offset voltage circuit 526, which are the determination level correction circuit 56.

Next, the operation of the first embodiment of the device of the present invention will be explained with reference to the waveform diagram shown in FIG. The output signal of the knocking detector 1 passes through a filter 51 to remove components other than the knocking frequency. The output signal of the filter 51 is rectified by a rectifying circuit 521, and smoothed by an integrating circuit 522 in which a capacitor and a resistor are connected in parallel (FIG. 3d). Here, the average value of the vibration input is output, and the amplifier 523 outputs the average value of the vibration input.
After multiplying (Fig. 3e), cylinder-specific judgment level circuit 5
6 and an offset voltage for obtaining a noise margin (FIG. 3f). This creates a judgment level for noticing and detection. This judgment level is determined by the rectifier circuit 52
It is compared with the output signal of No. 1 by the comparison circuit 527, and if the vibration signal after rectification is larger than the judgment level, it is determined that there is a knock and a pulse is output (No.
Figure g).

The detection signal from the combustion cylinder detector 2 is waveform-shaped via a waveform shaping circuit 55, and then sent to a voltage converter 561.
It is converted into a voltage (correction value) equal to the difference in determination level between cylinders (Fig. 3b). Adder 525
An offset voltage for reducing malfunction due to noise is added by an offset voltage circuit 526 (FIG. 3c). This signal is added to the aforementioned judgment level signal (Fig. 3e) in an adder 524 to create a desired judgment level. As a result of the above, the knock pulse (Fig. 3g) output from the knocking detection circuit depending on the presence or absence of knocking is:
The UP input of the ignition timing control U/D counter 53 is entered, and the count increases by one. If the knock pulse does not occur for one period, the advance angle timer indicates that the pulse is DOWN on the U/D counter.
Enters input and decreases the count by 1. The output of this counter is calculated in a retard calculation circuit 58 together with a reference ignition signal (supplied from a distribeater). As a result, when knocking occurs, a signal is output that retards the basic ignition timing, and when knocking does not occur for a certain period of time, advances the ignition timing. This signal is transmitted to the next closing angle control circuit 5.
9, the closing angle is controlled and sent to the igniter 4 as an ignition signal.

FIG. 4 shows a main block diagram of a second embodiment of the apparatus of the present invention. The second embodiment is structurally different from the first embodiment in that the amplifier 523 in the knocking detection circuit 52 is replaced with a variable gain amplifier 528;
Adder 525 is removed. The output of the voltage converter 561 is directly applied to the variable gain amplifier 528, and the offset voltage is directly applied to the adder 524 from the offset voltage circuit 526. The output signal of the voltage converter 561 changes the gain (correction value) of the variable gain amplifier 528, and the knock determination level is changed depending on the position of the cylinder in the combustion process. The waveform diagram in FIG. 5 shows the output signal waveforms of the main blocks in FIG. That is, FIG. 5a shows the output of the waveform shaping circuit 55, and FIG. 5b shows the output of the voltage converter 5.
61, FIG. 5c is the output of the rectifier circuit 521,
5d shows the output of the integrator, FIG. 5e shows the output of the variable gain amplifier 528, FIG. 5f shows the output of the adder 524, and FIG. 5g shows the output of the comparator 527.

According to the present invention, a combustion cylinder detector is provided to detect which cylinder is in the combustion process, and a predetermined correction value is selected based on the positional relationship between the combustion cylinder and the knock detector to determine the knock judgment level. change the
Stable knock detection is possible regardless of the position of the combustion cylinder, and appropriate ignition timing control can be performed.

[Brief explanation of the drawing]

FIG. 1 shows the first part of the ignition timing control device according to the present invention.
A block diagram showing the embodiment, FIG. 2 is the first block diagram of FIG. 1.
A detailed block diagram of the knocking detection circuit in the block diagram of the embodiment, FIG. 3 is an output waveform diagram of the main block diagram of the first embodiment of the present invention, and FIG. 4 is a diagram of the output waveform of the main block diagram of the first embodiment of the present invention. A block diagram showing the main parts and FIG. 5 are output signal waveform diagrams of the main blocks of the second embodiment of the present invention. 1... Knocking detector, 2... Combustion cylinder detector, 4... Igniter, 5... Ignition timing calculation circuit.

Claims (1)

[Scope of Claims] 1. A knocking detector that detects vibrations in the engine body or the outside due to the knocking phenomenon of the internal combustion engine, and ignition timing control that generates an ignition timing control signal in response to an output signal from the knocking detector. and an ignition device that generates an ignition signal based on an ignition timing control signal from the ignition timing control means, the ignition timing control device for an internal combustion engine comprising: a combustion cylinder for detecting a cylinder in a combustion process among the cylinders of the engine; The knocking determination level of the ignition timing control circuit is adjusted for each cylinder by selecting a correction value determined in advance based on the positional relationship between the combustion cylinder and the knocking detector according to the output signal from the combustion cylinder detector. 1. An ignition timing control device for an internal combustion engine, comprising: knocking determination level setting means for setting a knocking determination level. 2. Ignition timing control for an internal combustion engine according to claim 1, wherein the knocking determination level setting means sets the knocking determination level for each cylinder by adding a correction value equal to the difference in determination level between cylinders. Device. 3. The ignition timing for an internal combustion engine according to claim 1, wherein the knocking determination level setting means sets the knocking determination level for each cylinder by multiplying by a correction value corresponding to a difference in determination level between cylinders. Control device. 4. The ignition timing control device for an internal combustion engine according to claim 3, wherein the correction value is set as a gain of an amplifier for creating a knock determination level. 5. The ignition timing control device for an internal combustion engine according to claim 1, wherein the knocking determination level is created based on an output signal from the knocking detector.