JP2002357174A - Ignition timing control device for two cycle internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ignition timing control device for a two cycle internal combustion engine capable of suppressing the generation of detonation and reducing harmful gas discharged from an engine by optimally controlling ignition timing, and improving fuel economy and output of the engine. SOLUTION: In this ignition timing control device, by performing an ignition timing control process, basic timing calculated on the basis of an engine operating state in S120 is corrected by using correction amount calculated on the basis of a detection result of detonation in S170 or S180 (S200). Thereby, the generation of detonation can be suppressed, so that an air/fuel ratio need not to be set in a rich state (a state wherein fuel is thick), and the air/fuel ratio can be set in a leaner state of fuel than conventional. Exhaust harmful components discharged from the engine can be reduced, and the fuel comsumption and output of the engine can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an ignition timing control device for suppressing the occurrence of detonation in a two-cycle internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, a two-cycle internal combustion engine (hereinafter, referred to as a "combustion engine") has been known.
In a two-cycle engine, the oil is often of a gasoline-mixed type or an air-cooled type, and the cooling of the combustion chamber tends to be insufficient. In the case of a two-cycle engine, the intake and compression of the air-fuel mixture are performed in one stroke.
Unlike a cycle engine, an intake stroke for taking the air-fuel mixture into the combustion chamber does not exist as a single stroke, and therefore, the cooling of the combustion chamber by the air-fuel mixture during intake tends to be insufficient compared to a four-cycle engine. Furthermore, in recent years, in a two-stroke engine, a separation type in which oil is pressure-fed to a required portion is known, but cooling in a combustion chamber is not sufficient, and a water-cooling type is also known. Since the scavenging port is connected to the combustion chamber, there is a problem that it is difficult to secure a cooling water passage.

For this reason, in the two-cycle engine, the combustion chamber in the cylinder tends to be overheated, and a part of the inner wall of the combustion chamber becomes overheated. End gas) may self-ignite and knock may occur. When self-ignition is caused by such an overheated portion, each portion of the combustion chamber is overheated due to the self-ignition, and the number and scale of the portions that cause the same self-ignition increase (in other words, knocking becomes severe). Finally, the engine may burn. In such a two-stroke engine, abnormal combustion starting from one light knock to harder knock is generally called detonation.

[0004] A two-stroke engine uses one revolution per revolution.
Since this is an explosion and the cooling of the combustion chamber tends to be insufficient compared with the four-cycle engine as described above, the detonation proceeds at a high speed, and the time from the occurrence of detonation to the seizure of the engine is extremely long. It is also extremely difficult for the driver to perform some operation while driving to prevent the engine from burning.

For this reason, in a two-cycle engine, it is important to prevent knocking in the initial stage of detonation. Conventionally, in order to prevent such knocking from occurring, the air-fuel ratio (hereinafter also referred to as A / F) of the fuel mixture is described. 9) to about 9 to 10 rich air-fuel ratio (fuel rich)
, The temperature rise in the combustion chamber is suppressed. In other words, the combustion temperature of the fuel mixture decreases as the air-fuel ratio becomes richer (the fuel becomes richer). Therefore, by operating at a rich air-fuel ratio, the temperature rise in the combustion chamber is suppressed, and knocking is suppressed. .

[0006]

However, in recent years,
In order to prevent global warming and air pollution, two-cycle engines are also required to reduce CO2 and reduce harmful emissions by reducing fuel consumption, and are being regulated in various countries around the world. That is, it is no longer allowed to operate at a rich air-fuel ratio such as a set air-fuel ratio of 9 to 10. In addition, with a rich air-fuel ratio, not only does fuel efficiency deteriorate, but also the output of the engine is limited, and it is not possible to exhibit the maximum output unique to the engine.

For this reason, it is necessary to set the air-fuel ratio in the two-stroke engine to a state in which the fuel is thinner than in the past (in other words, lean). However, when the air-fuel ratio is set to a state in which the fuel is thin, detonation is likely to occur.

The present invention has been made in view of such a problem, and controls the two-cycle internal combustion engine to an optimum ignition timing in accordance with the detection of detonation. It is an object of the present invention to provide an ignition timing control device for a two-stroke internal combustion engine that can reduce harmful gas emissions and improve fuel efficiency and output of the engine.

[0009]

According to a first aspect of the present invention, there is provided an ignition timing setting means for setting an ignition timing based on an operating state of a two-cycle internal combustion engine, and a two-cycle internal combustion engine. Ignition means for spark discharge of a spark plug mounted on the engine, detonation detection means for detecting detonation generated by the mixture being self-ignited by a rise in the surface temperature of the combustion chamber wall, and detonation by the detonation detection means. Ignition timing correction means for correcting the ignition timing set by the ignition timing setting means so as to suppress the occurrence of the detonation based on the detection result, wherein the ignition means corrects the ignition timing by the ignition timing correction means. Spark ignition of a spark plug at a later ignition timing at the time of ignition of a two-cycle internal combustion engine A control device.

The present invention thus configured (Claim 1)
In the ignition timing control device, the ignition timing set by the ignition timing setting means is corrected by the ignition timing correction means based on the detection result of the detonation by the detonation detection means. Then, the ignition means causes the spark plug to spark-discharge at the corrected ignition timing corrected by the ignition timing correction means, whereby the two-cycle internal combustion engine is operated.

At this time, since the ignition timing correction means corrects the ignition timing so as to suppress the detonation, the detonation generated during the operation of the two-stroke engine can be suppressed from further progressing. Thus, when the detonation (knocking) occurs in the two-cycle engine, the present ignition timing control device can reliably prevent the detonation from entering the detonation circulation process up to the seizure of the two-cycle engine.

A two-stroke engine equipped with such an ignition timing control device has a function of automatically operating to suppress detonation. It is not necessary to set a rich (fuel rich) air-fuel ratio that does not cause detonation, but to a leaner (fuel thin) air-fuel ratio (set air-fuel ratio is 11 to 12 or more) as compared with the conventional case. can do.

Therefore, according to the ignition timing control device of the present invention (claim 1), it is possible to reduce the harmful exhaust components discharged from the two-cycle engine and to improve the fuel efficiency and output of the two-cycle engine. Can be. By the way, due to its structure, the two-cycle engine has a characteristic that vibration during operation is larger than that of the four-cycle engine. The reason is that piston slap (swinging phenomenon) occurs when the piston passes through the scavenging port, that it is one explosion per revolution, and that the number of cylinders is small (single cylinder or two cylinders) And the balance is unstable. For this reason, in the two-stroke internal combustion engine, when performing the detonation detection, when the electric signal output means for outputting the combustion state in the combustion chamber as an electric signal is mounted on the cylinder, the engine itself is compared with the four-stroke engine. Since the mechanical vibration and the vibration generated by combustion are large, it is important how to suppress the influence of noise caused by these vibration components.

Therefore, the detonation detecting means is mounted on the cylinder head of the two-stroke internal combustion engine and detects the in-cylinder pressure or vibration of the two-stroke internal combustion engine. Or an electric signal output means for outputting an electric signal corresponding to the vibration, an extracting means for extracting a signal component in a frequency band unique to detonation from the electric signal, and a detonation based on the magnitude of the signal component extracted by the extracting means. It is preferable to include an intensity calculating unit that calculates the intensity, and a detonation determining unit that determines the occurrence of detonation based on the detonation intensity calculated by the intensity calculating unit and a determination value for determining detonation.

That is, according to the present invention (claim 2), the effect of vibration noise generated by mechanical vibration of the engine itself or vibration due to combustion is suppressed, and detonation in a two-cycle engine is performed by using the above-described electric signal output means. This electric signal output means is arranged at a position closer to the combustion chamber than at a position farther from the combustion chamber in order to accurately detect the temperature. Specifically, instead of being mounted on a cylinder block as in a four-stroke engine, it is mounted on a cylinder head. Thus, in the two-cycle engine, a signal component in a frequency band unique to detonation can be accurately extracted from an output signal corresponding to the in-cylinder pressure or vibration of the internal combustion engine output from the electric signal output means. Then, the detonation intensity can be accurately calculated from the unique signal component, and the occurrence of detonation can be accurately determined based on the detonation intensity and the determination value for determining detonation.

Thus, according to the ignition timing control apparatus for a two-cycle internal combustion engine of the present invention (claim 2), the electric signal output means mounted on the cylinder head can reduce the influence of noise due to vibration during operation. , The presence or absence of detonation can be accurately detected. Thus, the occurrence of detonation can be reliably detected in the initial stage, and the ignition timing can be corrected by the ignition timing correction means so as to suppress the detonation. Therefore, the burn-in of the engine can be more reliably prevented.

Here, the electric signal output means mounted on the cylinder head of the above-described two-cycle internal combustion engine is provided in a form sandwiched between the spark plug and the cylinder head, and detects a change in the plug tightening load. And a knock sensor for detecting vibration transmitted from the combustion chamber to the cylinder head.

However, since the knock sensor detects the vibration of the internal combustion engine, in the combustion cycle in which detonation occurs, the detonation is detected based on an electric signal output according to the vibration of the internal combustion engine. Although it is possible, in a combustion cycle where detonation does not occur, especially when the operating state is in the high rotation range, the vibration noise is affected by the mechanical vibration of the engine itself, and the vibration noise is converted to the electric signal. There is a problem that they are easily superimposed. Therefore, the knock sensor may erroneously determine the occurrence of detonation in a combustion cycle in which detonation has not occurred.

Therefore, in the ignition timing control device for a two-cycle internal combustion engine according to the present invention, the electric signal output means is sandwiched between a spark plug and a cylinder head. It is preferable to use a plug washer-type pressure sensor having a piezoelectric element that is provided and outputs an electric signal corresponding to the in-cylinder pressure of the two-cycle internal combustion engine by detecting a change in the plug tightening load.

This plug washer-type pressure sensor has a built-in piezoelectric element, is sandwiched between a spark plug and a cylinder head, and is fixed in a state where an initial load is applied by a tightening load of the spark plug. When the air-fuel mixture burns or explodes in the combustion chamber, the spark plug itself is pushed up from the combustion chamber side by the pressure (in-cylinder pressure) generated by the combustion, and the load applied to the piezoelectric element changes from the initial load. Accordingly, an output signal (charge) corresponding to a change in the load applied to the piezoelectric element is output through a cable connected to the piezoelectric element, and a fluctuation in the cylinder pressure of the engine is determined based on the output signal (charge). Can be detected. The in-cylinder pressure detected by the plug washer-type pressure sensor is detected as a relative pressure.

When detonation occurs in a cylinder (combustion chamber), an abnormal pressure wave is generated in the combustion chamber, and abnormal vibration is generated in the cylinder by the pressure wave. At this time, since the in-cylinder pressure also fluctuates due to the abnormal pressure wave, a detonation-specific signal component is extracted from the electric signal by the plug washer-type pressure sensor for detecting the in-cylinder pressure mounted on the cylinder head. Thus, detonation can be detected based on the signal component and the detonation determination value. Since the tightening load of the ignition plug is hardly affected by the mechanical vibration of the engine itself, the output waveform output from the plug washer-type pressure sensor having the piezoelectric element is the output waveform output from the knock sensor. The superimposition of the noise component due to the mechanical vibration is reduced as compared with. That is, in order to detect detonation in a two-cycle internal combustion engine having large vibration, it is preferable to use the plug washer-type pressure sensor as an electric signal output unit mounted on a cylinder head.

In a two-cycle internal combustion engine, the magnitude of each amplitude of a vibration component generated by operation or a vibration component generated by detonation changes under the influence of the operation state (rotation speed, load, etc.) of the engine. Will do. For this reason, in a two-cycle engine, if the determination value for detonation determination is a fixed value,
Depending on the driving state, there is a possibility that the accuracy of the detonation determination is reduced. In other words, if the determination value is a fixed value and is a small value, the noise component may be erroneously determined to be a detonation in the high rotation region even though no detonation has occurred, If the value is a fixed value and is a large value, it is possible that the detonation cannot be detected in the low rotation region even though the detonation has occurred.

Therefore, as set forth in claim 4, the detonation detecting means includes a judgment value updating means for updating the judgment value to a value suitable for detonation judgment according to the operating state of the two-cycle internal combustion engine. Good. In other words, according to the operating state of the two-cycle internal combustion engine, a value suitable for detonation determination in the operating state is set as the determination value, so that appropriate detonation detection can be performed for each operating state.

Therefore, according to the ignition timing control device of the present invention (claim 4), accurate detonation detection is possible in all operating states, and it is possible to prevent a decrease in detonation detection accuracy. The ignition timing is controlled so as to suppress the detonation.
As described in the above, the ignition timing correction means, when the detonation is detected by the detonation detection means,
The ignition timing set by the ignition timing setting means is retarded using a predetermined correction amount. If detonation is not detected, the ignition timing set by the ignition timing setting means is advanced using the predetermined correction amount. Angle correction is recommended.

That is, when the ignition timing is corrected to the retard side, the temperature in the combustion chamber relatively decreases. Therefore, by retarding the ignition timing, the temperature in the combustion chamber can be reduced. In addition, the self-ignition of the air-fuel mixture can be suppressed, that is, detonation can be suppressed.

On the other hand, when the ignition timing is corrected to the retard side,
Although there is an effect of suppressing detonation, there is a disadvantage that the output of the engine is reduced. So, if no detonation is detected,
The advance of the ignition timing is corrected to increase the engine output.

According to the ignition timing control device of the present invention (claim 5), detonation can be suppressed by retarding the ignition timing when detonation is detected, and ignition can be performed when detonation is not detected. By advancing the timing, the engine output can be increased.

By the way, in correcting the ignition timing,
If the engine is excessively advanced or retarded excessively, it will not be possible to operate the engine normally, so if the ignition timing can be corrected without limit, the engine can be operated normally. May not be possible.

Therefore, the ignition timing correction means is provided when the corrected ignition timing deviates from a preset settable range so that the two-cycle internal combustion engine can operate normally. And ignition timing correction means for correcting the corrected ignition timing within the settable range.

That is, by correcting the corrected ignition timing so that it is always set within a settable range in which the engine can be normally operated, it is possible to prevent the engine from being unable to operate normally. Therefore, according to the ignition timing control device of the present invention (claim 6), the corrected ignition timing is not set in a range where the two-cycle internal combustion engine cannot normally operate, and the two-cycle internal combustion engine operates normally. can do.

Here, in the present ignition timing control device, when detonation is detected, the ignition timing correction means suppresses the detonation by retarding the ignition timing, but in order to suppress the detonation quickly. It is effective to carry out the retard correction with the correction amount increased. Conversely, when no detonation is detected, the ignition timing correction means attempts to improve the engine output by advancing the ignition timing, but if the correction amount is excessively increased and the advancing correction is made. However, detonation may occur immediately after that.

Therefore, the ignition timing correction means includes a correction amount setting means for setting a correction amount based on a detection result of the detonation by the detonation detection means. It is preferable to set a value having a larger change width than the correction amount when detonation is not detected as the correction amount when is detected.

That is, when detonation is detected, the correction amount setting means sets a value having a relatively large variation width to the correction amount as compared with the case where detonation is not detected, so that the ignition timing is greatly delayed. The angle is corrected and detonation is quickly suppressed. Further, when detonation is not detected, the correction amount setting means sets the correction amount to a value having a relatively small change width as compared with the case where detonation is detected, thereby increasing the advance correction amount of the ignition timing. By reducing the size, the output of the engine is improved while preventing the occurrence of detonation.

Therefore, according to the ignition timing control device of the present invention (claim 7), the generated detonation can be promptly suppressed and the output of the engine can be improved. By the way, even when the ignition timing is retarded or advanced using the same correction amount, if the operating state before correction is different, the change ratio of the operating state from before correction to after correction is different. For this reason, in order to set the operation state after the correction of the ignition timing to the operation state as the control target, it is necessary to set the correction amount after grasping the operation state before the correction.

Therefore, the correction amount setting means may set the correction amount based on the detonation intensity calculated by the intensity calculation means. That is,
Since the calculated detonation intensity is an index indicating the operation state of the engine, by setting the ignition timing correction amount based on the detonation intensity, the corrected operation state becomes the control target operation state. It controls the ignition timing.

For example, when the detonation intensity is large, the generation of detonation can be suppressed more reliably by setting the correction amount large. Conversely, when the detonation intensity is small, the correction amount is set to a small value, thereby suppressing the occurrence of detonation and suppressing a decrease in engine output.

According to the ignition timing control apparatus of the present invention (claim 8), the correction amount can be set according to the operating state of the two-cycle internal combustion engine, and the ignition timing is retarded or advanced. The subsequent operation state can be controlled to an appropriate operation state, and the fuel efficiency and output can be improved.

As a method of judging detonation by the detonation detecting means, there is a method of judging that detonation has occurred when the detonation intensity in one combustion cycle is equal to or greater than a judgment value for detonation. However, in the method of determining the presence or absence of detonation based on only the detonation intensity calculated in one combustion cycle, an error occurs in the calculated value of the detonation intensity due to the influence of a noise component, and detonation occurs. It is possible to determine that detonation has occurred even though it has not occurred, or to determine that detonation has not occurred even though detonation has occurred. May not be possible.

Therefore, as set forth in claim 9, the detonation detecting means is provided in the predetermined number of combustion cycles.
A detonation occurrence frequency calculated by the detonation occurrence frequency calculated by the detonation occurrence frequency calculated by the detonation determination means is a detonation occurrence frequency. If the value is equal to or greater than the determination value, it may be determined that detonation has occurred.

That is, of the predetermined number of combustion cycles,
The detonation occurrence frequency is calculated as a detonation occurrence frequency, and the presence or absence of detonation is determined by comparing the detonation occurrence frequency with the frequency determination value. This gives 1
Rather than determining whether or not detonation has occurred based on only the detonation intensity calculated in the combustion cycle, the detonation occurrence status can be grasped based on a plurality of detonation intensities calculated in a predetermined combustion cycle, so that more accuracy is achieved. The presence or absence of occurrence of detonation can be determined well.

In the combustion cycle of the predetermined cycle,
In calculating the detonation occurrence frequency at which the detonation intensity is equal to or greater than the determination value, it is preferable to calculate the detonation occurrence frequency in a section that is a certain number of cycles earlier than the current combustion cycle. Thus, the detonation occurrence frequency is updated for each combustion cycle, and the detonation occurrence frequency is constantly updated to the latest value, so that more accurate detonation determination can be performed.

Here, the frequency of occurrence of detonation, like the intensity of detonation, is an index indicating the operating state of the engine. Therefore, the correction amount setting means may set the correction amount based on the detonation occurrence frequency calculated by the frequency calculation means.

That is, by using the detonation occurrence frequency, the operating state of the engine can be grasped more accurately, and the corrected operating state can be more accurately brought closer to the control target operating state. Then, when the frequency of occurrence of detonation is high, the occurrence of detonation can be suppressed more reliably by setting the correction amount to a large value and correcting the ignition timing with retard. Conversely, when the frequency of occurrence of detonation is low, the correction amount is set to be small and the advance correction amount of the ignition timing is made small, so that it is possible to suppress the occurrence of detonation and to suppress a decrease in the engine output.

Therefore, according to the ignition timing control device of the present invention (claim 10), the correction amount can be set according to the operation state of the two-cycle internal combustion engine, and the operation state after the ignition timing is corrected can be set. Since it can be controlled to an appropriate operation state, it is possible to improve fuel efficiency and output.

Some two-cycle internal combustion engines do not include a battery for the purpose of weight reduction depending on the application. In such a two-cycle internal combustion engine, power is generated by using the rotation of the engine, and the generated voltage is controlled. Is supplied to each part to operate the engine. However, in the two-cycle internal combustion engine configured as described above, the generated voltage may fluctuate due to a change in the rotation speed of the engine, or the generated voltage at the start may become unstable. In this case, there is a risk that the devices of the various parts of the engine may not operate normally. For example, when the ignition timing control is performed by internal processing of a microcomputer (hereinafter, also referred to as a microcomputer), the power supply voltage decreases and the microcomputer If normal operation cannot be performed, ignition timing control becomes impossible.

Therefore, in the above-described ignition timing control apparatus for a two-cycle internal combustion engine, a power supply for generating an AC voltage by a magnetic flux change generated by a magnet rotating together with an output shaft of the two-cycle internal combustion engine is provided. Coil, a voltage rectifying unit that outputs an AC voltage generated in the power supply coil as a rectified and smoothed DC voltage, and ignites a driving voltage as a constant voltage using the DC voltage output from the voltage rectifying unit. A voltage output unit that outputs to each unit of the timing control device, and reserve power is charged by a DC voltage output from the voltage rectification unit, and is discharged to the voltage output unit by discharging the reserve power when the DC voltage decreases. And a voltage fluctuation suppressing unit that suppresses fluctuation of the voltage value.

That is, when power is supplied to each unit using the power supply coil and the voltage rectification unit, the voltage output unit
By using a DC voltage output from the voltage rectification unit to output a drive voltage as a constant voltage, a constant voltage is supplied to each unit. Further, the voltage fluctuation suppressing unit discharges the reserve power charged by the DC voltage when the DC voltage decreases, thereby suppressing a fluctuation in the voltage value input to the voltage output unit, thereby enabling the voltage output unit to operate. Variations in the output drive voltage can be suppressed.

Therefore, according to the ignition timing control device of the present invention (claim 11), power is generated by utilizing the rotation of the engine,
In supplying power to each unit, fluctuations in voltage value due to a change in the engine rotation speed or at the time of engine start can be suppressed, and a stable voltage supply can be performed. This allows
Even when the engine is started or the operating state fluctuates, the operating state of each device that operates by receiving the drive voltage can be stabilized, and the ignition timing control can be stabilized even when executing the ignition timing control as internal processing of the microcomputer. And run it.

[0049]

Embodiments of the present invention will be described below with reference to the drawings. First, FIG. 1 shows a configuration diagram of an ignition timing control device 1 of the present embodiment. The ignition timing control device 1
It is provided in a two-cylinder two-cycle engine (hereinafter, also simply referred to as an engine). Further, the two-cylinder two-cycle engine is not provided with a battery, and is configured to supply voltage to each unit by a voltage generated by an exciter coil described later.

As shown in FIG. 1, the ignition timing control device 1
Is a central processing unit 3 (hereinafter also referred to as a CPU),
It includes a signal processing circuit 11, a waveform shaping circuit 33, a processing / protection circuit 37, an ignition system circuit 39, and a power supply circuit 43. First, the CPU 3 is configured by a semiconductor integrated circuit, and is for comprehensively controlling the ignition timing, the rotation speed, and the like of the internal combustion engine. In addition to the ignition timing control processing described later, the CPU 3 is used in the ignition timing control processing. Ignition control processing for generating spark discharge in the spark plug at the set ignition timing,
An operation state detection process for detecting an operation state of the engine based on a detection signal or the like of a sensor provided in each part of the engine,
A fuel control process for setting a fuel supply amount based on the detected operating state is performed. Note that, in the CPU 3, FIG.
In addition to the signals shown in (1), signal input / output is performed with sensors and actuators.

The signal processing circuit 11 includes a first charge amplifier 13, a second charge amplifier 15, an analog switch 17, a filter circuit 19, a peak hold circuit 21, and a background level detection circuit 23. ing. First, the first charge amplifier 13 amplifies an electric signal output from the first plug washer-type pressure sensor GPS1 mounted on the cylinder head of the first cylinder of the engine and outputs the amplified signal as a first cylinder pressure signal Sc1. The second charge amplifier 15 includes a second plug washer-type pressure sensor GP mounted on the cylinder head of the second cylinder of the engine.
The electric signal output from S2 is amplified and output as a second in-cylinder pressure signal Sc2.

The first plug washer-type pressure sensor GPS
Each of the first and second plug washer-type pressure sensors GPS2 is configured to include a piezoelectric element. Although not shown, the plug washer-type pressure sensor is sandwiched between a cylinder head and a spark plug (more specifically, a mounting seat of a metal shell constituting the spark plug).
It is fixed (mounted) to the cylinder head while an initial load is applied by the tightening load of the spark plug. When the air-fuel mixture burns or explodes in the combustion chamber of the first cylinder or the second cylinder, the ignition plug itself is pushed up from the combustion chamber side by the pressure (in-cylinder pressure) generated by the combustion, and is given to the piezoelectric element. Load changes from initial load. Therefore, the electric signal (charge) output from the piezoelectric element changes with the change in the load, and the first plug washer-type pressure sensor GPS1 and the second plug-washer-type pressure sensor GPS2 are connected to the first cylinder and the second cylinder. Each of the cylinders operates to output an electric signal in accordance with the in-cylinder pressure.

The first in-cylinder pressure signal Sc1 and the second
The in-cylinder pressure signal Sc2 is input to the analog switch 17,
The analog switch 17 outputs one of the first cylinder pressure signal Sc1 and the second cylinder pressure signal Sc2 to the filter circuit 19 based on the cylinder switching signal Sm from the CPU 3.

Next, based on the signal input from the analog switch 17, the filter circuit 19 extracts a signal component in a frequency band unique to the detonation from a fluctuation component of the in-cylinder pressure in either the first cylinder or the second cylinder. hand,
The extracted signal component is output as a detonation signal Sf. The filter circuit 19 of the present embodiment has a frequency of 6 kHz.
z] to 10 [kHz]. Note that the filter circuit 19 is not limited to the band-pass filter circuit of this frequency band, and may be configured by a band-pass filter circuit or a high-pass filter circuit that extracts a signal component of a frequency band unique to the detonation.

Then, the peak hold circuit 21
During a certain period after the piston of either the cylinder or the second cylinder reaches the top dead center (TDC) (hereinafter also referred to as a peak value detection period), the peak value of the detonation signal Sf is detected and held, A / D
After the conversion, it is output as a peak signal Sp. Note that the peak hold circuit 21 sets the peak value detection period based on the input timing of the pulse signal St from the outside,
Immediately before the start time of the peak value detection period, the held peak value is deleted, and thereafter, the detection of the peak value in the peak value detection period is started.

At this time, the input timing of the pulse signal St is
Since the crank angle is set at a predetermined position, the peak hold circuit 21 counts the elapsed time in the circuit based on the input timing of the pulse signal St to determine the current position of the rotation angle of the crankshaft. Calculate and set the peak value detection period. The peak hold circuit 21 of the present embodiment sets the respective peak value detection periods of the first cylinder and the second cylinder after reaching the top dead center (hereinafter referred to as AT).
DC) [0 CA ATDC] to 60 [° CA
ATDC].

In the two-cylinder two-cycle engine provided with the present ignition timing control device 1, the strokes of the combustion cycles of the first cylinder and the second cylinder are operated with the phase shifted by 180 °° CA. I have. Therefore, the peak hold circuit 21 operates to detect the peak value of the first cylinder and the peak value of the second cylinder alternately.

Next, the background level detection circuit 2
3 is a predetermined period (hereinafter referred to as B) before a piston of either the first cylinder or the second cylinder reaches the top dead center (TDC).
GL detection period), calculate and hold the average value of the signal level (amplitude) of the detonation signal Sf,
After A / D conversion of the held average value, it is output as a background signal Sb. Note that the background level detection circuit 23 sets the BGL detection period based on the input timing of the pulse signal St from the outside, and deletes the held average value immediately before the start timing of the BGL detection period. Then, the average value in the subsequent BGL detection period is calculated.

As described above, since the input timing of the pulse signal St is set at a timing when the crank angle reaches a predetermined position, the background level detection circuit 23
The BGL detection period is set by calculating the current position of the rotation angle of the crankshaft by counting the elapsed time in the circuit based on the input timing of the pulse signal St. Then, the background level detection circuit 23 of the present embodiment
Sets the BGL detection period of each of the first cylinder and the second cylinder before reaching the top dead center (hereinafter, also referred to as BTDC) 12.
The setting is made to be [° CA BTDC] to 0 [° CA BTDC].

As described above, in the two-cylinder two-cycle engine provided with the ignition timing control device 1, the first
The stroke of each combustion cycle of the cylinder and the second cylinder is 180
[° CA] Operation is performed with the phase shifted. Therefore, the background level detection circuit 23 operates to alternately detect the average value of the detonation signal of the first cylinder and the average value of the detonation signal of the second cylinder.

As described above, the signal processing circuit 11 performs the peak value detection period set after reaching the top dead center on the basis of the signals from the first plug washer mold pressure sensor GPS1 and the second plug washer mold pressure sensor GPS2. The peak value of the detonation signal is detected and output as a peak signal Sp. In addition, the signal processing circuit 11 detects an average value of the detonation signal during the BGL detection period set before reaching the top dead center, and outputs the average value as the background signal Sb.

The waveform shaping circuit 33 includes a pulsar coil 31 for generating an induced voltage in synchronization with the rotation of the crankshaft.
And outputs a pulse signal St to each of the CPU 3, the peak hold circuit 21, and the background level detection circuit 23 each time the rotation angle of the crankshaft reaches a predetermined crank angle based on the output voltage from the CPU.

Then, the CPU 3 calculates the engine speed and the like and determines which stroke each cylinder is in based on the input timing of the pulse signal St, the input time interval, and the like. As described above, the peak hold circuit 21 calculates the current position of the rotation angle of the crankshaft based on the input timing of the pulse signal St, and sets the peak value detection period. Further, as described above, the background level detection circuit 23 calculates the current position of the rotation angle of the crankshaft based on the input timing of the pulse signal St, and sets the BGL detection period.

Next, the processing / protection circuit 37 executes A / D conversion based on a signal from the throttle sensor 35 for detecting the opening of the throttle valve for adjusting the intake air amount, and sends the throttle valve to the CPU 3. Is output as a valve opening signal Sv. Then, the CPU 3 calculates an intake air amount, an engine load, and the like based on the valve opening signal Sv.

The ignition system circuit 39 has at least a capacitor, and discharges the charging voltage charged in the capacitor to the primary winding of the ignition coil 51, thereby realizing a so-called capacity discharge type for discharging the ignition plug. And a well-known circuit for performing the operation. The charging voltage charged to the capacitor in the ignition system circuit 39 is discharged based on the ignition signal IG from the CPU 3 to change the magnetic flux density in the ignition coil 51 and apply the ignition voltage to the secondary winding. Generate voltage. The ignition system circuit 39
After discharging the capacitor, the capacitor can be charged to a predetermined voltage before the next ignition timing. The voltage for charging the capacitor is supplied from the exciter coil 41. Has been. The secondary winding of the ignition coil 51 is connected in series with the first spark plug 53 mounted on the first cylinder and the second spark plug 55 mounted on the second cylinder, and the secondary winding is ignited. The generation of the high voltage for use causes the first spark plug 53 and the second spark plug 55 to simultaneously generate spark discharge.

In the engine of this embodiment, since the ignition timings of the first cylinder and the second cylinder are different from each other, for example, spark discharge may occur even in the second cylinder where the ignition timing of the first cylinder is not the ignition timing. become. However, the first spark plug 5
3. By configuring the second spark plug 55 and the ignition coil 51 in this way, a single ignition coil 51 can generate a high voltage for ignition of two cylinders, which has the effect of reducing costs. .

The power supply circuit 43 is connected to an exciter coil 41 that generates an AC voltage by a magnetic flux change generated by a magnet that rotates together with the output shaft of the two-cycle engine, and rectifies and smoothes the AC voltage output from the exciter coil 41. The converted DC voltage is output to each part of the ignition timing control device 1.

Here, a configuration diagram of the power supply circuit 43 is shown in FIG. As shown in FIG. 2, the power supply circuit 43 includes a rectifier circuit 45.
, Three-terminal regulator 47, charging capacitors C1 and C2, and voltage stabilizing capacitors C3 and C3.
4, a first terminal T1 and a second terminal T2 connected to both ends of the exciter coil 41, respectively, and a third terminal T3 for outputting a constant voltage Vcc.

The second terminal T2 is connected to the ground inside the power supply circuit 43, and an induced voltage Vi1 generated at both ends of the exciter coil 41 is applied to the first terminal T1. The rectifier circuit 45 includes a diode D1 having an anode connected to the first terminal T1 and a diode D1.
A resistor R1, one end of which is connected to the cathode of the first resistor and the other end of which is connected to the ground via a resistor R2;
A Zener diode ZD1 having a cathode connected to a connection point thereof, a resistor R3 having one end connected to the anode of the Zener diode ZD1 and the other end connected to ground,
A thyristor S1 having an anode connected to the first terminal T1, a cathode connected to the ground, and a gate connected to a connection point between the anode of the Zener diode ZD1 and the resistor R3.
And The connection point between the diode D1 and the resistor R1 is connected to the input terminal 47a of the three-terminal regulator 47.
It is connected to the.

In the rectifier circuit 45 thus configured, when the potential Vi1 of the first terminal T1 becomes higher than 0 [V], a current flows in the order of the diode D1, the resistor R1, and the resistor R2. When the potential Vi1 rises, the current flowing through the diode D1, the resistor R1, and the resistor R2 rises. When the voltage across the resistor R2 rises and exceeds the Zener voltage of the Zener diode ZD1, the cathode of the Zener diode ZD1 rises. Current starts flowing in the direction from to the anode. As described above, a voltage is generated across the resistor R3 by the current flowing through the Zener diode ZD1, and when the voltage across the resistor R3 exceeds the drive voltage of the thyristor S1, the thyristor S1 is turned on.
Current starts to flow from the anode to the cathode of the thyristor S1. Then, the current input from the first terminal T1 is divided into the direction toward the diode D1 and the direction toward the thyristor S1, and the current value flowing toward the diode D1 is suppressed from further increasing.
Further increase in the potential V1 at the connection point between the resistor 1 and the resistor R1 is suppressed.

In the rectifier circuit 45, when the potential Vi1 of the first terminal T1 becomes lower than 0 [V], no current flows through each element in the circuit. That is, the rectifier circuit 4
5 outputs a voltage (potential V1) to the three-terminal regulator 47 when the potential Vi1 input from the exciter coil 41 to the first terminal T1 becomes a positive potential of 0 [V] or more. Conversely, the potential Vi1 input to the first terminal T1
Becomes negative potential lower than 0 [V], the rectifier circuit 45 does not output a voltage to the three-terminal regulator 47. The rectifier circuit 45 is a three-terminal regulator 47.
Is limited to a certain voltage value or less by turning on the thyristor S1.

Next, in the three-terminal regulator 47, the input terminal 47a is connected to the connection point between the diode D1 and the resistor R1 of the rectifier circuit 45, the reference terminal 47c is connected to ground, and the output terminal 47b is connected to the third terminal T3. It is connected to the. The three-terminal regulator 47 is connected to the input terminal 47.
A constant voltage (in the present embodiment,
5 [V]) is output from the output terminal 47b.

Further, between the input terminal 47a of the three-terminal regulator 47 and the reference terminal 47c, charging capacitors C1 and C2 are connected. The charging capacitors C1 and C2 are output from the rectifier circuit 45. Is charged by applying a voltage to both ends with a potential V1. The charging capacitor C1 is formed of a large-capacity capacitor. When the potential V1 output from the rectifier circuit 45 decreases, the charged capacitor C1 is discharged to the three-terminal regulator 47 by discharging the charged charge. Voltage is prevented from dropping.

Further, between the output terminal 47b of the three-terminal regulator 47 and the reference terminal 47c, voltage stabilizing capacitors C3 and C4 are connected, and the voltage stabilizing capacitors C3 and C4 are Charging is performed by applying a voltage to both ends by the output constant voltage. The voltage stabilizing capacitor C3 is composed of a large-capacity capacitor. When the constant voltage output from the three-terminal regulator 47 decreases, the charged electric charge is discharged to discharge the charged electric charge from the power supply circuit 43. The output constant voltage Vcc is prevented from lowering.

The power supply circuit 43 configured as described above converts an AC voltage generated by the exciter coil 41 into a DC voltage and outputs the DC voltage as a constant voltage Vcc. The provision of the charging capacitors C1 and C2 and the voltage stabilizing capacitors C3 and C4 suppresses fluctuation of the output constant voltage Vcc.

Although FIG. 1 shows only the voltage path to ignition system circuit 39 with respect to the voltage path of constant voltage Vcc output from power supply circuit 43,
Voltage paths are also provided for devices such as 3 that operate by receiving power supply and all circuits (including the charge amplifiers 13 and 15 and the analog switch 17) such as the filter circuit 19 and the peak hold circuit 21. The constant voltage Vcc is output to each device and each circuit.

Next, the ignition timing control processing executed by the CPU 3 will be described with reference to the flowchart shown in FIG. The ignition timing control process is started for each cylinder at the same time as the two-cylinder two-cycle engine is started, and each cylinder is repeatedly executed once in one combustion cycle.

When the ignition timing control process is started, first, in S110, the engine speed (hereinafter, also referred to as engine speed) calculated in the operating state detection process separately executed by the CPU 3 and detected. A process for reading the throttle opening is performed. In the next S120, S11
Based on the operating state (engine speed and throttle opening) read at 0, a process of reading a basic ignition timing and a detonation determination level (hereinafter also referred to as a detonation determination level) from a map is performed. And this S120
The map for setting the detone judgment level in
The detoning determination level is set using the operating state as a parameter. This map has a value larger than a signal component in a frequency band unique to the detonation among vibration components (hereinafter, also referred to as a noise component) generated by factors other than the detonation, and a signal component in a frequency band unique to the detonation. It is configured to set a smaller value than the detonation determination level.

At S130, it is determined whether or not the operating state of the two-stroke engine is in a transition region (acceleration region or deceleration region). The process proceeds to S150 when a negative determination is made (when the region is not in the transition region). That is,
Since the transition region is a region in which the operation state of the engine changes, if the ignition timing is corrected in such a transition region, the operation state of the engine may become unstable, and the operation state may become unstable. Therefore, in the present ignition timing control process, the ignition timing is corrected after determining that the region is in a stable operating state which is not a transient region.

Then, if a positive determination is made in S130, S1
In S140, the value of the basic ignition timing read in S120 is output to an ignition control process separately executed inside the CPU 3. Then, the separately executed ignition control processing is performed based on the basic ignition timing based on the ignition system circuit 3.
9 by controlling the output of the ignition signal IG for
A spark discharge is generated at the basic ignition timing received from the ignition timing control processing. Then, when the process of S140 is performed, the main ignition timing control process ends.

If a negative determination is made in S130, the program proceeds to S15.
In S150, the sensitivity of the plug washer-type pressure sensor (GPS) is corrected, the knock intensity (detonation intensity) is calculated, and the previous correction value is calculated. Here, the sensitivity correction of the plug washer-type pressure sensor is performed by the background signal S from the background level detection circuit 23 described above.
b. Specifically, the peak signal Sp from the peak hold circuit 21 is
The sensitivity is corrected by dividing by b.

The knock intensity is calculated by correcting the value of the peak signal Sp from the peak hold circuit 21 with GPS sensitivity. Further, the previous correction value is calculated by a final correction value (final retard correction value or final advance correction value) calculated in S190 described later in the previous combustion cycle.
From a storage area (memory or the like).

In the next S160, it is determined whether or not detonation has occurred based on the knock intensity calculated in S150. If an affirmative determination is made (in the case of detonation occurrence), the process proceeds to S170, and a negative determination is made. If this is the case (when detonation has not occurred), the flow shifts to S180. In S160, the detonation determination level read in S120 is compared with the knock intensity calculated in S150. If the knock intensity is equal to or greater than the detonation determination level, it is determined that detonation has occurred (a positive determination), and the knock intensity is determined. When it is lower than the detonation determination level, it is determined that detonation has not occurred (negative determination).

Then, an affirmative determination is made in S160 and S17
After shifting to 0, in S170, a retard correction value is calculated using a map based on the knock intensity calculated in S150. Here, FIG. 4 shows an example of a map for calculating the correction amount based on the knock intensity. Then, as shown in FIG. 4, the map used in S170 sets a larger value for the retard correction amount as the knock intensity increases, and sets a smaller value for the retard correction amount as the knock intensity decreases. It is configured. For this reason, in the ignition timing control device of the present embodiment, when detonation occurs, a larger value is set for the retard correction amount as the knock intensity increases, and a smaller value is set for the retard correction amount as the knock intensity decreases. Will be.

Further, a negative determination is made in S160 and S180
In S180, the advance angle correction value is calculated using the map based on the knock intensity calculated in S150. At this time, the map used for the processing in S180 is:
It is set so that a value whose change width is smaller than the minimum value of the correction amount that can be set in the map used in the processing in S170 is calculated as the advance correction amount.

When the processing in S170 or S180 is completed, the flow shifts to S190.
0 or the final correction value (the final retardation correction value or the final advance correction value) based on the correction amount (the retard correction amount or the advance correction amount) calculated in S180 and the previous correction value calculated in S150. ) Is calculated. The calculated final correction value is used for the next combustion cycle.
It is stored in a storage area (such as a memory).

Here, in the present combustion cycle, S1
The knock intensity calculated at 50 is a value obtained as a result of ignition at the ignition timing corrected in the previous combustion cycle, that is, the final ignition timing. In contrast, S1
The map used in 70 or S180 is configured to calculate a correction value based on knock intensity obtained as a result of ignition at the basic ignition timing.

For this reason, for example, the final correction value is calculated to be −4 [° CA] (minus represents retardation correction) in S190 in the previous combustion cycle, and in the present combustion cycle, the correction value is calculated in S180. Is calculated as 3 [° CA] (plus represents advance correction), the final correction value (in this example, final delay correction Value). By performing such processing, the ignition timing in the current combustion cycle can be appropriately corrected.

At S200, the final ignition timing is calculated by correcting the basic ignition timing calculated at S120 using the final correction value calculated at S190. In addition,
At this time, if the corrected final ignition timing deviates from a preset settable range so that the two-cycle engine can operate normally, in S200, the final ignition timing is set to a value within this settable range. Fix it. Specifically, if the final ignition timing after the correction deviates to the retard side from the settable range, the most retarded value in the settable range is set as the final ignition timing, and conversely, When the final ignition timing deviates from the settable range to the advanced angle side, the most advanced value in the settable range is set as the final ignition timing.

In the next step S210, the value of the final ignition timing calculated in step S200 is output to an ignition control process separately executed inside the CPU 3. Then, the separately executed ignition control process controls the output of the ignition signal IG to the ignition system circuit 39 based on the final ignition timing to generate a spark discharge at the final ignition timing received from the ignition timing control process. .

When the processing in S140 or S210 is executed, the main ignition timing control processing ends. Further, the ignition timing control process is executed independently for each cylinder as described above.
The current stroke of each cylinder is determined by executing a current stroke determination process of determining the current stroke of each cylinder based on the pulse signal St from the third cylinder. Then, the current stroke determination process outputs a cylinder switching signal Sm based on the determination result to control the analog switch 17 and, among the first cylinder and the second cylinder, the signal of the cylinder in the BGL detection period or the peak value detection period. The analog switch 17 is controlled to output. Further, the ignition timing control processing is executed independently for each cylinder in synchronization with the respective strokes of the first cylinder and the second cylinder based on the determination result of the current stroke determination processing.

In the ignition timing control device of this embodiment, the ignition control process executed as an internal process of the CPU 3 corresponds to the ignition means described in the claims. S120, S150, and S160 in the signal processing circuit 11 and the ignition timing control processing correspond to the detonation detection means, and correspond to S170, S170 in the ignition timing control processing.
180, S190, and S200 correspond to ignition timing correction means.

The filter circuit 19 in the signal processing circuit 11 corresponds to the extracting means described in the claims.
S150 in the ignition timing control processing corresponds to the intensity calculation means, S160 corresponds to the detonation determination means, the detonation determination level corresponds to the determination value, and S120 corresponds to the determination value updating means.

Further, S20 in the ignition timing control process
0 corresponds to the ignition timing correction means described in the claims, and S170 and S180 correspond to the correction amount setting means. The exciter coil 41 corresponds to a power supply coil described in the claims, the rectifier circuit 45 in the power supply circuit 43 corresponds to a voltage rectifier, and the three-terminal regulator 4
7 corresponds to a voltage output unit, and the charging capacitors C1 and C2 correspond to a voltage fluctuation suppressing unit.

As described above, in the ignition timing control device 1 provided in the two-stroke engine of the present embodiment, the basic ignition timing calculated based on the operating state of the engine is executed by executing the ignition timing control processing. , Using the correction amount calculated based on the detonation detection result. Then, the ignition control process causes the spark plug to spark-discharge at the corrected final ignition timing corrected by the ignition timing control process, whereby the two-cycle engine is operated.

In the ignition timing control process, when the detonation is detected, the basic ignition timing is retarded and the detonation is suppressed, so that the detonation generated during the operation of the engine is suppressed from further progressing. can do. Thus, when detonation (knocking) occurs in the two-stroke engine, the present ignition timing control device can reliably prevent the detonation from entering the detonation circulating process until the engine seizes.

The two-stroke engine provided with such an ignition timing control device can suppress the generated detonation. Therefore, unlike the conventional two-stroke engine, the air-fuel ratio of the fuel mixture supplied to the engine can be reduced. It is not necessary to set a rich (fuel rich) air-fuel ratio that does not cause detonation, and it is possible to set the air-fuel ratio to a state where the fuel is thinner than in the past.

Therefore, according to the ignition timing control device of the present embodiment, it is possible to reduce the harmful exhaust components discharged from the two-cycle engine and to improve the fuel efficiency and output of the two-cycle engine. In addition, in the ignition timing control process, when the detonation is not detected, the basic ignition timing is advanced and thus the engine output can be increased.

In the present ignition timing control device, in the ignition timing control process in step S200, the corrected final ignition timing falls within a predetermined settable range so that the two-cycle engine can operate normally. If you deviate,
The final ignition timing is corrected within this settable range. As a result, the final ignition timing is not set in a range where the two-cycle engine cannot operate normally, and the two-cycle engine can be operated normally.

Further, in the present ignition timing control device, the correction amount when the detonation is detected (the correction amount calculated in S170) is larger than the correction amount when the detonation is not detected (the correction amount calculated in S180). Is also set to a value with a large change width. For this reason, when detonation is detected, the ignition timing is greatly retarded, and detonation can be suppressed promptly. When detonation is not detected, the ignition timing is advanced. By reducing the correction amount, the output of the engine can be improved while preventing the occurrence of detonation.

Further, the present ignition timing control device sets a detonation determination level according to the operating state, and can set a value suitable for detonation determination in the operating state as the detonation determination level. Therefore, the present ignition timing control device can perform appropriate detonation detection for each operation state, and can prevent a decrease in detonation detection accuracy.

The ignition timing control device is driven by a DC voltage obtained by rectifying and smoothing an AC voltage generated by an exciter coil 41 by a power supply circuit 43 instead of supplying a voltage from a battery. The power supply circuit 43 includes charging capacitors C1 and C2 and a voltage stabilizing capacitor C1.
3 and C4, the output constant voltage Vc
The variation of c is suppressed.

Therefore, according to the present ignition timing control device, it is possible to suppress the fluctuation of the voltage value due to the change of the engine speed or the start of the engine, and it is possible to supply the voltage stably. This makes it possible to stabilize the operation state of each device that operates by receiving the drive voltage even when the engine is started or the operating state fluctuates, and to stably execute the ignition timing control, which is an internal process of the CPU. Can be.

Next, the results of measurements performed to compare the output and fuel efficiency when the two-stroke engine is operated with the present ignition timing control device and the output and fuel efficiency when operating under the conventional operating conditions are described. Will be described below. The two-cycle engine used in this measurement had an ignition timing (basic ignition timing) during normal operation of 1 cycle before top dead center.
The operation is performed at 4 [° CA BTDC].

First, the first measurement of the output will be described. In the first measurement, the conventional air-fuel ratio (A / F =
10.0) and the case where the fuel is operated at an air-fuel ratio (A / F = 10.5) where the fuel is thinner than in the conventional case. The output (torque) of the engine was measured.
Further, the air-fuel ratio is set to a state where the fuel is thinner than before (A / F =
10.5) By operating the engine using the ignition timing control device of the embodiment, it was measured to which position the ignition timing was finally controlled.

FIG. 5 shows the result of the first measurement. FIG. 5 is a coordinate plane in which the horizontal axis indicates ignition timing and the vertical axis indicates torque, and the horizontal axis indicates the rotation angle of the crankshaft before top dead center (hereinafter referred to as BTDC). Further, in FIG. 5, data (hereinafter, referred to as first data) when the operation is performed at the conventional air-fuel ratio (A / F = 10.0) is represented by a dotted line, and the air-fuel ratio (A / F = 10.
The data (hereinafter referred to as second data) when the operation is performed in 5) is indicated by a solid line.

As shown in FIG. 5, both the first data and the second data indicate that the more the ignition timing is advanced, the more the torque increases. When A / F = 10.0, knock occurs when the ignition timing is advanced from 18 [° CA BTDC], so that the ignition timing is 18 [° CA BTDC].
The area on the more advanced side than DC] is the knock generation area when A / F = 10.0. When A / F = 10.5, knock occurs when the ignition timing is advanced to 14 [° CA BTDC].
[A BTDC], the A / F = 10.
This is the knock generation area at time 5.

FIG. 5 shows the final control position of the ignition timing when operated using the ignition timing control device of the present embodiment as the "final control position of the ignition timing". As a result of this measurement, the final control position of the ignition timing is about 13.7 [° CA
BTDC], and the torque at this time is about 4.7 [N ·
m]. On the other hand, if the air-fuel ratio is A / F = 10.0,
When operating under the conventional operating conditions in which the ignition timing is 14 [° CA BTDC], the torque is about 3.75 [N ·
m].

From these measurement results, the air-fuel ratio was changed to A / F
= 10.0 and the ignition timing is 14 [° CA BTDC]
In comparison with the case of driving under the conventional operating condition of fixing at,
It can be seen that the torque is increased by about 25% when the operation is performed using the ignition timing control device.

Next, the second measurement of the fuel consumption will be described. In the second measurement, (a) the air-fuel ratio is set to the same state as the conventional state (A / F = 10.0), and the ignition timing is set to 14 [°
CA BTDC], (b) when the air-fuel ratio is thinner than before (A / F = 10.5), and when the ignition timing is fixed at 14 [° CA BTDC],
(C) The air-fuel ratio is set to a state where the fuel is thinner than before (A / F = 1
0.5), and the ignition timing is controlled using the ignition timing control device of the present invention including the plug washer-type pressure sensor,
(D) The air-fuel ratio is set to a state where the fuel is thinner than before (A / F = 1
When the ignition timing was controlled using the ignition timing control device of the present invention having a knock sensor, the fuel consumption rate was measured in each of the four operating states.

FIG. 6 shows the result of the second measurement. FIG. 6 is a coordinate plane in which the horizontal axis represents each operating state and the vertical axis represents the fuel consumption rate. From the measurement results shown in FIG. 6, the fuel consumption rate in each operation state is about 445 [g / (kw · h)] in the case of (a) and about 310 [g / (kw) in the case of (b). H)], and in the case of (c), about 32
0 [g / (kw · h)], and in the case of (d), about 370
[G / (kw · h)]. And (a) and (c)
Comparing the measurement results of (a) and (c), since the fuel consumption rate is smaller than that of (a), the ignition timing control is performed using the ignition timing control device of the present invention. It can be seen that is improved. The improvement rate of the fuel consumption rate by using the ignition timing control device of the present invention is about 28% as compared with the related art.

Note that the operating state (b) is the limit value of the fuel consumption rate of the engine used in this measurement, and in the operating state where the value of the fuel consumption rate further decreases (fuel efficiency improves), It becomes a dangerous operation state in which there is a risk of damage to the vehicle. In addition, even when the ignition timing control device of the present invention is used, the case of (c) using the plug washer-type pressure sensor as the sensor and the knock sensor for detecting mechanical vibration corresponding to knocking are used ( There is a difference in the fuel consumption rate even in the case of d). This is because the knock sensor has a structure that detects mechanical vibration.
Since the plug washer pressure sensor has a structure that detects in-cylinder pressure, the plug washer pressure sensor is less affected by noise components due to mechanical vibration of the engine, and the knocking (detonation) detection accuracy is higher. It is.
And, by increasing the knocking detection accuracy,
The ignition timing control device can detect the operating state of the engine with higher accuracy, and thus can set the ignition timing to a more optimal value.

The embodiments of the present invention have been described above. However, the present invention is not limited to these embodiments, and can take various forms. For example, in the ignition timing control device of the above embodiment (hereinafter, referred to as a first embodiment), detonation detection is performed based on the detonation intensity. However, detonation detection may be performed based on the detonation occurrence frequency.

Thus, as a second embodiment, an ignition timing control device that performs detonation detection based on the frequency of detonation occurrence will be described. The ignition timing control device of the second embodiment is specifically realized by changing the ignition timing control process executed by the central processing unit of the first embodiment as follows.

First, after S150, the knock intensity calculated in S150 is compared with the detonation determination level calculated in S120, and the comparison result is stored, and detonation is performed based on the comparison result of a certain number of past combustion cycles from now. Step of calculating the occurrence frequency (hereinafter, S15
1).

Further, instead of the processing of S160, S15
A step (hereinafter referred to as S171) for determining whether or not the detonation occurrence frequency calculated in step 1 is equal to or higher than a predetermined detonation determination frequency determination level is set. If an affirmative determination is made in S171, S1
The process proceeds to S70, and if a negative determination is made in S171, S1
Move to 80.

In S170, a process of calculating a retard correction value using a map is performed based on the detonation occurrence frequency calculated in S151. Also in S180, a process of calculating an advance correction value using a map is performed based on the detonation occurrence frequency calculated in S151.

When the frequency of occurrence of detonation is high, the occurrence of detonation can be suppressed more reliably by setting the correction amount large and correcting the ignition timing with retard. Conversely, when the frequency of detonation occurrence is low, the correction amount is set small and the ignition timing advance correction amount is reduced, thereby suppressing the occurrence of detonation.
A decrease in engine output can be suppressed.

In the ignition timing control device of the second embodiment, S151 in the ignition timing control processing corresponds to the frequency calculating means described in the claims, S171 corresponds to the detonation determining means, and S170 S18
0 corresponds to the correction amount setting means.

In the ignition timing control device of the second embodiment, the frequency judgment level used for the processing in S171 is provided as a predetermined fixed value, but the frequency judgment level is changed according to the operation state. Thus, the frequency of occurrence of detonation can be determined with higher accuracy.

Further, in both the first embodiment and the second embodiment, the peak value detection period is set to 0 to 60 [° CA ATDC].
However, the peak value detection period is not limited to this range, and an optimum range may be set for each engine.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an ignition timing control device according to an embodiment.

FIG. 2 is a configuration diagram of a power supply circuit in the ignition timing control device.

FIG. 3 is a flowchart showing the contents of an ignition timing control process executed by a central processing unit.

FIG. 4 is an example of a map for calculating a correction amount based on knock intensity.

FIG. 5 shows the air-fuel ratio when the fuel is thinner than before (A / F
= 10.5) is the measurement result of the first measurement of the final control position of the ignition timing when the engine is operated using the ignition timing control device of the present invention.

FIG. 6 is a measurement result of a second measurement of the fuel consumption rate in each of four types of operation states.

[Explanation of symbols]

1: ignition timing control device, 3: central processing unit (CP
U), 11: signal processing circuit, 19: filter circuit, 21
... peak hold circuit, 23 ... background level detection circuit, 41 ... exciter coil, 43 ... power supply circuit,
45 rectifier circuit, 47 three-terminal regulator, C1, C
2 ... Charging capacitor, GPS1: First plug washer pressure sensor, GPS2: Second plug washer pressure sensor.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02P 13/00 303 F02P 17/00 R 17/12 (72) Inventor Masayoshi Matsui Takatsuji, Mizuho-ku, Nagoya-shi, Aichi Prefecture No. 14-18, Nihon Special Ceramics Co., Ltd.F-term (reference) FA07 FA10 FA21 FA25 FA33 FA38

Claims (11)

[Claims] 1. An ignition timing setting means for setting an ignition timing based on an operation state of a two-cycle internal combustion engine, an ignition means for spark discharge of an ignition plug mounted on the two-cycle internal combustion engine, and a surface temperature of a wall of a combustion chamber A detonation detecting means for detecting a detonation generated when the air-fuel mixture self-ignites due to the rise, and the ignition timing setting means based on a detection result of the detonation by the detonation detecting means, so as to suppress the occurrence of the detonation. Ignition timing correction means for correcting the set ignition timing, wherein the ignition means discharges the spark plug at the corrected ignition timing corrected by the ignition timing correction means. Timing control device for a two-stroke internal combustion engine. 2. The detonation detecting means is mounted on a cylinder head of the two-stroke internal combustion engine, detects an in-cylinder pressure or vibration of the two-stroke internal combustion engine, and outputs an electric signal corresponding to the in-cylinder pressure or the vibration. An electric signal output unit for outputting a signal component in a frequency band unique to detonation from the electric signal; and an intensity calculation for calculating a detonation intensity from a magnitude of the signal component extracted by the extraction unit. Means, and detonation judging means for judging occurrence of the detonation based on the detonation intensity calculated by the intensity calculating means and a judgment value for judging detonation. 2. The ignition timing control device for a two-cycle internal combustion engine according to claim 1. 3. The cylinder of the two-stroke internal combustion engine according to claim 3, wherein the electric signal output means is provided so as to be sandwiched between the spark plug and the cylinder head, and detects a change in a plug tightening load. The ignition timing control device for a two-cycle internal combustion engine according to claim 2, wherein the pressure sensor is a plug washer-type pressure sensor having a piezoelectric element that outputs an electric signal according to an internal pressure. 4. The detonation detecting means includes a judgment value updating means for updating the judgment value to a value suitable for detonation judgment in accordance with an operation state of the two-stroke internal combustion engine. The ignition timing control device for a two-stroke internal combustion engine according to claim 2 or 3. 5. The ignition timing correction means, when detonation is detected by the detonation detection means, retards the ignition timing set by the ignition timing setting means using a predetermined correction amount, and The method according to any one of claims 1 to 4, wherein when the detonation is not detected, the ignition timing set by the ignition timing setting means is advanced using a predetermined correction amount. An ignition timing control device for a two-stroke internal combustion engine. 6. The ignition timing correction means, when the corrected ignition timing deviates from a preset settable range so that the two-cycle internal combustion engine can operate normally. The ignition timing control device for a two-stroke internal combustion engine according to any one of claims 1 to 5, further comprising: ignition timing correction means for correcting a timing within the settable range. 7. The ignition timing correction means includes a correction amount setting means for setting a correction amount of the ignition timing based on a detection result of detonation by the detonation detection means, wherein the correction amount setting means detects the detonation. The two-cycle internal combustion engine according to any one of claims 1 to 6, wherein a value having a larger variation width than the correction amount when no detonation is detected is set as the correction amount when the detonation is detected. Engine ignition timing control device. 8. The two cycles according to claim 2, wherein the correction amount setting unit sets the correction amount based on the detonation intensity calculated by the intensity calculation unit. An ignition timing control device for an internal combustion engine. 9. The detonation detecting means may determine a rate of occurrence of a combustion cycle in which the detonation intensity is equal to or greater than the determination value among a predetermined number of combustion cycles.
The detonation determining unit includes a frequency calculating unit that calculates the detonation occurrence frequency, and the detonation determining unit determines that detonation has occurred when the detonation occurrence frequency calculated by the frequency calculating unit is equal to or greater than a frequency determination value for detonation determination. The ignition timing control device for a two-stroke internal combustion engine according to any one of claims 2 to 7, wherein the determination is made. 10. The two-stroke internal combustion engine according to claim 9, wherein the correction amount setting unit sets the correction amount based on the detonation occurrence frequency calculated by the frequency calculation unit. Ignition timing control device. 11. A power supply coil for generating an AC voltage by a magnetic flux change generated by a magnet rotating together with an output shaft of the two-cycle internal combustion engine, and a DC voltage generated by rectifying and smoothing the AC voltage generated in the power supply coil. A voltage output unit that outputs a driving voltage as a constant voltage to each unit of the ignition timing control device using the DC voltage output from the voltage rectification unit; Charging a reserve power with the DC voltage, and discharging the reserve power when the DC voltage decreases, thereby suppressing a variation in a voltage value input to the voltage output unit. The ignition timing control device for a two-stroke internal combustion engine according to any one of claims 1 to 10, further comprising: