JP2001152918A - Two-cycle engine control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device which can actuate a two-cycle engine without generating detonation, and improve fuel consumption and output performances. SOLUTION: Whether detonation (knocking) occurs at an engine or not is determined based on sensed signal from a cylinder internal pressure sensor (140). When the detonation occurs, an increasing correction value α1 is added to a correction value KKN in respect to a reference pulse width at the time of driving an injector (150). When the detonation does not occur, a decreasing correction value α2 less than the value α1 is decreased from the correction value KKN (160). The correction value KKN is thus updated. A final pulse width for determining a fuel supply amount to an engine is calculated by correcting the reference pulse width while adapting the updated correction value KKN (190). As a result, a fuel supply amount to the engine is increased at the time of detonation, for cooling the inside of a combustion chamber. Detonation occurrence can thus be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-stroke engine control device for controlling a fuel supply to a two-stroke engine.

[0002]

2. Description of the Related Art Conventionally, in a two-stroke engine, oil is often of a gasoline-mixed type or an air-cooled type, and the cooling of a combustion chamber tends to be insufficient. In addition, compared to four cycles, the number of cycles in which outside air can be taken into the combustion chamber and cooled can be reduced, so that the cooling time is shortened. Furthermore,
Since the scavenging port is in the vicinity of the combustion chamber and obstructs, even if the oil is of a separate type or of a water-cooled type,
There is a problem that it is difficult to secure a passage that can sufficiently cool oil and cooling water.

[0003] For this reason, a very small portion of the combustion chamber in the cylinder tends to be overheated. Further, when the superheated portion self-ignites, each part of the combustion chamber is overheated due to this, and the same self-ignition portion is heated. The number and scale will expand. Then, a pre-ignition in which the surface self-ignites before the regular ignition is accompanied, and the pre-ignition becomes more intense.
Eventually, a runaway surface ignition occurs, and the engine runs away and burns. In the two-stroke engine, all abnormal combustion starting from one light knocking to harder knocking, preignition, and runaway surface ignition is generally called detonation.

[0004] The time until such an engine burn-in is very short, and it is extremely difficult for the driver to perform any operation while driving to prevent it. In many cases, it is impossible to stop the engine burning at the stage when the initial knocking occurs. As shown in FIG. 5, the frequency of occurrence of such detonation tends to increase as the air-fuel ratio (hereinafter also referred to as A / F) becomes leaner.

On the other hand, in order to solve these problems, 4
It is conceivable to apply ignition timing retard control (control of detecting knocking to retard ignition timing) generally used in a cycle engine to a two-cycle engine. However, in such ignition timing retard control, Since it is not possible to rapidly lower the temperature of a part of the overheated combustion chamber, it is difficult and impractical to stop the circulation process that occurs in a two-stroke engine from the occurrence of detonation to the seizure of the engine.

For this reason, conventionally, in a two-cycle engine, the air-fuel ratio of the fuel-air mixture has been set to a rich air-fuel ratio of about 9 to 10. That is, in a two-cycle engine, it is important to prevent the first knocking of one shot. Therefore, conventionally, the two-cycle engine is operated at a rich air-fuel ratio so that such knocking does not occur. It was.

[0007]

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 the rich air-fuel ratio, not only does the fuel economy deteriorate, but also the output of the engine is limited, and there is a problem that the maximum output unique to the engine cannot be exhibited.

The present invention has been made in view of such a problem, and can not only operate a two-cycle engine without generating detonation but also reduce harmful exhaust gas emitted from the two-cycle engine. It is an object of the present invention to provide a two-stroke engine control device capable of improving fuel efficiency and output of a cycle engine.

[0009]

Means for Solving the Problems and Effects of the Invention The invention according to claim 1 which has been made to achieve the above object has the following features.
Fuel supply amount setting means for setting a fuel supply amount based on an operation state of the cycle engine; and fuel supply means for supplying fuel to the two-cycle engine with the fuel supply amount set by the fuel supply amount setting means. A two-cycle engine control device comprising: a detonation detecting means for detecting a detonation in which self-surface ignition occurs due to a rise in the surface temperature of the combustion chamber; and a fuel supply means for detecting a detonation detected by the detonation detecting means. Fuel correction means for increasing and correcting the supply amount.

The present invention thus configured (Claim 1)
Is provided with detonation detecting means for detecting a detonation that causes self-surface ignition due to a rise in the surface temperature of the combustion chamber of the two-stroke engine. When detonation is detected by the detonation detecting means, the fuel correction means includes a fuel supply means. Corrects the amount of fuel supplied to the two-stroke engine. Therefore, if knocking occurs during operation of the two-cycle engine, more fuel is supplied to the combustion chamber than the fuel supply amount set by the fuel supply amount setting means, and the supplied fuel quickly cools the combustion chamber. Will be done.

Therefore, according to the present invention, when detonation (knocking) occurs in the two-stroke engine, the combustion chamber is quickly cooled, and then it is ensured that the detonation circulates until the engine seizes. Can be prevented. Further, as described above, according to the present invention, since the detonation generated in the two-cycle engine can be suppressed, like the conventional two-cycle engine,
The air-fuel ratio of the fuel mixture supplied to the engine does not need to be set to a rich air-fuel ratio that does not cause detonation, and can be set to a leaner air-fuel ratio than usual. Therefore, according to the present invention, it is possible to reduce harmful exhaust components emitted from the engine, and to improve fuel efficiency and output.

Here, the fuel correction means may be configured to simply increase the fuel supply amount by a predetermined amount when the detonation is detected, but more preferably, as described in claim 2 or 3, It is good to constitute. That is, first, in the two-cycle engine control device according to claim 2,
When the detonation is detected by the detonation detection means, the fuel correction means increases the correction amount for the fuel supply amount by a predetermined increase correction amount, and when no detonation is detected, the correction amount for the fuel supply amount is increased by the increase correction amount. A correction amount updating unit configured to reduce the fuel supply amount set by the fuel supply amount setting unit based on the correction amount set by the correction amount updating unit; The fuel supply by the fuel supply means is executed at the later fuel supply amount.

For this reason, in the two-stroke engine control device according to the second aspect, when the detonation occurs, the fuel supply amount supplied from the fuel supply means to the two-stroke engine is increased by the increase correction amount, and detonation occurs. If not, the decrease correction is performed gradually with the decrease correction amount smaller than the increase correction amount, and the two-cycle engine is controlled toward the detonation occurrence limit region. Therefore, if the two-stroke engine control device is configured as described in claim 2, the fuel supply amount to the two-stroke engine can be reduced as much as possible within a range in which detonation does not occur. As compared with the case where the amount is increased, it is possible to further improve the fuel efficiency and the output.

[0014] On the other hand, in the two-stroke engine control device according to claim 3, the fuel correction means calculates a detonation occurrence frequency based on a detonation detection result by the detonation detection means, and the frequency calculation means includes: Correction amount setting means for setting a correction amount for the fuel supply amount such that the higher the frequency of detonation occurrence, the higher the fuel supply amount based on the detonation occurrence frequency calculated. The fuel supply amount set by the fuel supply amount setting means is corrected on the basis of the fuel correction amount set in step (1), and the fuel supply by the fuel supply means is executed with the corrected fuel supply amount.

Therefore, in the two-cycle engine control device according to the third aspect, the fuel supply amount supplied from the fuel supply means to the two-cycle engine is increased or decreased according to the frequency of occurrence of detonation. The correction amount is
In the two-cycle engine, the frequency of detonation converges to an optimum value at which the set value (target value) is reached.

Therefore, when the two-cycle engine control device is configured as described in claim 3, the frequency of detonation of the two-cycle engine can be controlled to the target value, and the fuel to the two-cycle engine can be controlled. The supply amount can be reduced as much as possible within a range where detonation does not adversely affect the operation of the engine, and the fuel consumption and output can be more improved than when the fuel supply amount is increased only when detonation is detected. It is possible to improve.

By the way, the detonation of a two-cycle engine starts from the occurrence of one knocking, is accompanied by preignition, becomes a runaway surface ignition state, and finally leads to engine seizure. For this reason, it is too late if the pre-ignition has already started, but in the stage before that, it is possible to prevent the development of pre-ignition by retarding the ignition timing and lowering the combustion temperature.

Further, as in the present invention (claims 1 to 3), when the detonation occurs (knocking occurs), the amount of fuel is increased and corrected to prevent the detonation from deteriorating. However, there is a problem of fuel transportation delay. Therefore, in the device for increasing the amount of fuel when detonation occurs as described in claims 1 to 3, furthermore, when detonation is detected by the detonation detecting means as described in claim 4, It is preferable that not only the fuel supply amount increase correction by the fuel correction means but also the ignition timing delay control by the ignition timing delay means be performed at the same time.

According to the two-stroke engine control device of the fourth aspect, when the detonation occurs, the temperature of the combustion chamber can be reduced by correcting the increase of the supplied fuel and retarding the ignition timing. Thus, occurrence of detonation can be more reliably prevented.

On the other hand, as the detonation detecting means,
Detecting engine vibration, such as a knocking sensor that is attached to the outer wall of an engine that has been conventionally used in a four-cycle engine and detects its vibration, and an in-cylinder pressure sensor that detects the pressure in a cylinder applied to a spark plug An element may be used, but in this case,
By judging whether or not the detection signal from the detecting element is larger than a predetermined threshold, it is determined whether or not detonation has occurred. It is possible that

That is, in a two-cycle engine,
Since the vibration amplitude other than detonation increases significantly in the high rotation region, if the threshold for detonation determination is fixed, the detonation detection sensitivity changes depending on the engine speed, and erroneous determination of detonation occurrence in the high rotation region It is possible that the detonation cannot be detected despite the occurrence of detonation in the low rotation region.

Therefore, as the detonation detecting means, a detecting element for detecting vibration of the two-cycle engine and a threshold value for detonation determination are set based on the rotation speed of the two-cycle engine. Comparing the detection signal from the detection element with the threshold value set by the threshold value setting means, and when the detection signal exceeds the threshold value, detonation occurs. And determination means for determining the condition.

With this configuration of the detonation detecting means, the threshold value for determining detonation can be set in accordance with the engine speed, so that the detonation is not affected by the two-cycle engine speed. The detection accuracy can be kept constant, and the above-described engine control (increase control of fuel supply amount, retard control of ignition timing, etc.) performed to prevent the occurrence of detonation can be performed.
It can be performed with high accuracy.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram illustrating a two-cycle engine (hereinafter, simply referred to as an engine) and peripheral devices of an embodiment to which the present invention is applied.

The engine 1 of this embodiment is provided with a scavenging port 2, a crank chamber 3, a spark plug 4, a reed valve 5, a throttle valve 6, and an injector 15 as a fuel supply means. The engine 1 also includes a throttle opening sensor 10 for detecting a throttle opening, a crank angle sensor 11 for generating a detection signal each time the engine 1 rotates a predetermined crank angle, and a spark plug as sensors for detecting the operation state. 4, an in-cylinder pressure sensor 12 for detecting engine vibration (specifically, a change in in-cylinder pressure), an intake air temperature sensor 13 for detecting intake air temperature, and an atmospheric pressure sensor 14 for detecting atmospheric pressure. Have been. The in-cylinder pressure sensor 12 corresponds to a detection element for detecting detonation.

The detection signals from these sensors are input to an engine control unit (hereinafter referred to as ECU) 20. The ECU 20 includes a CPU, an RO
M, RAM, and the like, and calculates a fuel supply amount and an ignition timing based on a detection signal from each of the above sensors, and calculates a fuel supply amount from the injector 15 and a spark plug 4. The ignition timing (specifically, high voltage generation timing of an ignition coil (not shown) for applying a high voltage for spark discharge to the ignition plug 4) is controlled.

The ECU 20 is provided with a signal processing circuit for passing a signal of a predetermined frequency band corresponding to the detonation among the output signals from the in-cylinder pressure sensor 12. The ignition plug 4 functions as an ignition means together with an ignition coil (not shown) and its drive circuit.

Next, a control process (in this embodiment, a fuel injection pulse calculation process) executed to suppress detonation (initial knocking) generated in the engine 1 by the ECU 20 will be described with reference to a flowchart shown in FIG. Will be explained. This processing is executed in synchronization with the rotation of the engine 1 based on the detection signal from the crank angle sensor 11.

As shown in FIG. 2, when this processing is started, first, in S100 (S represents a step), the throttle opening obtained by the detection signal from each of the above-mentioned sensors,
The engine rotation speed, the atmospheric pressure, the intake air temperature, and the in-cylinder pressure are read, and in S110, a basic pulse width is calculated from the read throttle opening, engine speed, atmospheric pressure, and intake air temperature.

The basic pulse width is determined by the injector 1
Valve opening time of 5 (in other words, fuel supply to engine 1)
In this embodiment, the process of S110 functions as a fuel supply amount setting unit.
The basic pulse width is calculated, for example, by using a map (not shown) with the throttle opening and the engine speed as parameters to find the pulse width under standard atmospheric conditions.
The procedure is such that the intake air temperature correction value set based on the intake air temperature is multiplied by the atmospheric pressure correction value set based on the atmospheric pressure.

Thus, when the basic pulse width is calculated,
In S120, during a preset detonation determination period (engine rotation region where knocking is likely to occur),
The detection signal from the in-cylinder pressure sensor 12 is sampled,
The average value is calculated as the background noise level BGL included in the in-cylinder pressure detection signal. In step S130, a threshold value SL for detonation determination is set from the engine speed using a map shown in FIG. 5A, for example. Execute

The map shown in FIG. 5A is set such that the higher the engine speed, the larger the threshold value SL. This is because, as described above, in the two-cycle engine, the vibration amplitude other than the detonation increases remarkably in the high rotation region, so that the occurrence of the detonation can be accurately determined without being affected by this. It is.

When the background noise level BGL of the in-cylinder pressure detection signal and the threshold SL for detonation determination are calculated as described above, the process proceeds to S140.
It is determined whether or not the detonation has occurred in the engine 1 by determining whether or not the peak value of the in-cylinder pressure detection signal sampled in S120 is greater than a value obtained by adding the noise level BGL to the threshold value SL. A process as a determining means according to claim 5 for determining whether or not the above is performed.

If the in-cylinder pressure is greater than "BGL + SL", it is determined that detonation has occurred in the engine 1, and the flow shifts to S150, where a correction value KKN for the basic pulse width (in other words, a correction amount for the fuel supply amount). ) Is added to the preset increase correction value α1, thereby updating the correction value KKN. Conversely, when the in-cylinder pressure is “BGL + S
If L is equal to or less than L, it is determined that detonation has not occurred in the engine 1, and the flow shifts to S160 to correct the preset reduction correction value α2 from the correction value KKN for the basic pulse width to obtain the correction value KKN. To update.

The processing in S150 and S160 corresponds to the correction amount updating means according to claim 2, and the reduction correction value α2 is set to a value sufficiently smaller than the increase correction value α1. This is because when the detonation is detected, the correction value K
When KN is increased, the correction value KKN is increased at a stretch to suppress detonation quickly, and the engine 1
The amount of fuel supply to the fuel cell is rapidly increased, and conversely, when no detonation is detected, the correction value KKN is gradually decreased,
This is to prevent the fuel supply amount to the engine 1 from suddenly decreasing.

Next, in S150, when the correction value KKN for the basic pulse width is increased and corrected, this time in S170
And the correction value KKN is set to the preset upper limit value Kma.
x, and determines whether the correction value KKN is equal to the upper limit Kma.
If it exceeds x, in S180, the correction value KKN is set to the upper limit value Kmax, and then the process proceeds to S190. Conversely, if the correction value KKN does not exceed the upper limit value Kmax, the process directly proceeds to S190.

If the correction value KKN for the basic pulse width is corrected to decrease in S160, then in S200
And the correction value KKN is changed to the preset lower limit value Kmi.
n is determined, the correction value KKN is set to the upper limit K
If it is less than min, the correction value KKN is set to the lower limit value Kmin in S210, and then the process proceeds to S190, and conversely,
If the correction value KKN is not less than the upper limit Kmin, the process directly proceeds to S190.

At S190, the correction value K updated according to the detonation determination result at S140.
By multiplying KN by the basic pulse width calculated in S110, the basic pulse width is corrected, and the final pulse width for actually supplying fuel to the engine 1 by actually opening the injector 15 is calculated. The processing as the fuel correcting means according to claim 2 is executed, and the processing is terminated.

As described above, in the present embodiment, whether or not detonation (knocking) has occurred in the engine 1 is determined based on the detection signal from the in-cylinder pressure sensor 12, and if detonation has occurred, Increases the fuel supply amount to be injected from the injector 15 to the engine 1 by increasing the correction value KKN for the basic pulse width by the increase correction value α1.

For this reason, if knocking occurs during the operation of the engine 1, the combustion chamber is quickly cooled by increasing the fuel supply amount. Therefore,
According to the present invention, when knocking, which is an initial detonation, occurs in the engine 1, the combustion chamber is quickly cooled, and thereafter, the engine 1 enters a detonation circulation process such as knocking → pre-ignition → seizure. Can be reliably prevented.

Further, in this embodiment, when detonation occurs, the correction value KKN for the basic pulse width is corrected using the increase correction value α1, so that the basic pulse width is largely changed to the fuel increase side, and detonation is not generated. In some cases, the correction value KKN for the basic pulse width is corrected using the decrease correction value α2 smaller than the increase correction value α1, thereby gradually changing the basic pulse width toward the fuel reduction side. The fuel supply amount to the engine 1 is corrected to be as small as possible within a range in which detonation does not occur. Therefore,
According to the present embodiment, the conventional 2 which is operated at the rich air-fuel ratio
Compared to a cycle engine, fuel efficiency and output can be improved, and exhaust harmful components discharged from the engine can be reduced.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and can take various forms. For example, in the above embodiment,
Although it has been described that only the fuel supply amount to the engine 1 is increased or decreased according to the detection result of the detonation, the ECU
At 20, the fuel injection pulse width as shown in FIG.
If the ignition timing calculation process is executed, when the detonation occurs, the fuel supply amount increase correction and the ignition timing retard control can be performed simultaneously, so that the detonation can be more reliably prevented.

Hereinafter, the fuel injection pulse width / ignition timing calculation processing shown in FIG. 3 will be described. As shown in FIG. 3, in this process, similarly to the above-described embodiment, first, in S100, the throttle opening, the engine rotation speed, the atmospheric pressure, the intake air temperature, and the in-cylinder pressure are read, and in S110, they are read. The basic pulse width is calculated from the throttle opening, the engine speed, the atmospheric pressure, and the intake air temperature.

Next, after calculating the basic pulse width, the process proceeds to S310, where the basic ignition timing ADVBASE is calculated using a preset map based on the basic pulse width obtained in S110 and the engine speed. The processing as the ignition timing setting means is executed.

Then, as in the above embodiment,
In S120, S130, and S140, processing as detonation detecting means is executed. When it is determined in S140 that detonation has occurred in engine 1, S32 is executed.
0, the retard correction value ADVKNK (negative value) for retarding the ignition timing (advance value) is subtracted from the current value by a predetermined crank angle β, so that it is retarded. I do.

When the retard correction value ADVKNK is updated in this way, it is determined in S340 whether the updated retard correction value ADVKNK is larger than a preset lower limit value LLMT. If the angle correction value ADVKNK is larger than the lower limit value LLMT, the process directly proceeds to the subsequent S150, and conversely, the retard correction value ADVKNK sets the lower limit value LLM.
If T or less, the retard correction value ADVKNK is set to the lower limit LL.
After setting to MT, the process proceeds to subsequent S150. And
In S150, similarly to the above-described embodiment, the increase correction value α1 is added to the correction value KKN for the basic pulse width,
The correction value KKN is updated, and thereafter, in S170 and S180, a process for limiting the upper limit of the correction value KKN is performed.
Move to 190.

On the other hand, if it is determined in S140 that detonation has not occurred in the engine 1, the routine proceeds to S330, in which the ignition timing retard correction value ADVKNK is set to an initial value "0", and then to S160. Move to And S
At 160, the correction value KKN is updated by subtracting the decrease correction value α2 from the correction value KKN for the basic pulse width, as in the above-described embodiment, and thereafter, at S200 and S210, the lower limit of the correction value KKN is limited. After performing the processing, S
Move to 190.

In step S190, the basic pulse width is corrected by multiplying the correction value KKN by the basic pulse width, and the injector 15 is actually opened, and the engine 1
Then, the final pulse width for injecting and supplying the fuel is calculated, and the process proceeds to S360. Then, in S360, S31
0, the basic ignition timing ADVBASE calculated at S32
0 to S350, the ignition timing retard correction value A set in the process
By correcting using DVKNK, the final ignition timing ADV at which the spark plug 4 is actually spark-discharged is calculated,
The process ends.

In this processing, the processing of S320 to S350 for setting the retard correction value ADVKNK in accordance with the result of the detonation determination in S140, and the correction of the basic ignition timing ADVBASE using the retard correction value ADVKNK S360. The function as the ignition timing retarding means according to the fourth aspect is realized by the above processing.

As described above, in the fuel injection pulse width / ignition timing calculation processing shown in FIG. 3, not only the basic pulse width (in other words, the amount of fuel supplied to the engine 1) is corrected according to the detonation determination result. When the detonation is determined, the ignition timing retard correction value ADVKNK is set to a value smaller than the initial value “0”, and the basic ignition timing AD
VBASE is corrected to the retard side.

Therefore, if this processing is executed in the ECU 20, when the detonation occurs, the temperature of the combustion chamber is controlled by controlling both the increase correction of the fuel supply to the engine 1 and the retard correction of the ignition timing. Can be reduced, control responsiveness can be improved, and the occurrence of detonation can be more reliably prevented as compared to the case where the occurrence of detonation is prevented only by increasing the amount of supplied fuel.

In the fuel injection pulse width / ignition timing calculation processing shown in FIG. 3, when it is determined that detonation has not occurred, the ignition timing retard correction value ADVKNK is determined.
Is set to the initial value "0" so that the ignition timing is not corrected for retardation (in other words, the ignition timing is controlled to the basic ignition timing ADVBASE obtained in S310), but detonation occurs. When it is determined that the ignition timing has not been adjusted, for example, in S330, a predetermined value β2 is added to the ignition timing retard correction value ADVKNK, whereby the retard correction value ADVKNK is corrected to the side that advances the ignition timing. You may make it.

That is, in this manner, similarly to the fuel injection amount, the ignition timing is corrected to the retard side or the advance side in accordance with the presence or absence of detonation.
By ending the retard correction of the ignition timing immediately after the determination result of 0 is reversed from "with detonation" to "without detonation", it is possible to prevent the occurrence of detonation again.

However, if the retard correction value ADVKNK is corrected to the advance side in S330, the corrected retard correction value ADVKNK becomes larger than the initial value "0". And the ignition timing is the basic ignition timing A
It is preferable not to make correction on the advance side than DVBASE.

In the above embodiment, the correction value KKN for the basic pulse width is set by increasing or decreasing according to the detection result of the detonation. Is performed in the procedure shown in FIG. 4, and the correction value KKN for the basic pulse width is
May be set based on the frequency of occurrence of detonation.

Hereinafter, the fuel injection pulse calculation processing shown in FIG. 4 will be described. As shown in FIG. 4, in this process, as in the fuel injection pulse calculation process shown in FIG. 2, the operation state of the internal combustion engine is read in S100, the basic pulse width is calculated in S110, and the basic pulse width is calculated in S120 to S140. To determine whether detonation has occurred. If it is determined in S140 that detonation has occurred, S
At 410, the flag FKNK is set to a value "1" indicating the presence of detonation, and then the process proceeds to S430. Conversely, when it is determined at S140 that detonation has not occurred, the flag is set at S420. After resetting FKNK to a value “0” indicating no detonation, S4
Move to 30.

In S430, the frequency of detonation (detonation frequency) CKNK is determined based on the flag FKNK set and reset in S410 and S420.
The processing as the frequency calculating means according to claim 3 is executed. The frequency calculation can use a knocking frequency calculation method conventionally performed for knocking control in a four-cycle engine, and a detailed description thereof will be omitted.

Then, in S440, based on the detonation frequency CKNK obtained in S430, for example, FIG.
The processing as the correction amount setting means according to claim 3, wherein a correction value KKN for the basic pulse width is calculated using a map set as shown in (b).

When the correction value KKN is calculated in this manner, the basic pulse width is corrected by multiplying the calculated correction value KKN by the basic pulse width in step S190, as in the above embodiment. After executing the processing as fuel correction means according to claim 3, which calculates the final pulse width for injecting and supplying fuel to the engine 1 by actually opening the valve 15, the processing is ended.

The map for calculating the correction value shown in FIG. 6B shows that the higher the detonation frequency CKNK, the higher the correction value K
KN increases, and detonation frequency CKN
In an area where K is high, the correction value KKN is a value larger than “1”, and in an area where the detonation frequency CKNK is low,
The correction value KKN is set so as to be smaller than “1”. This is because the higher the detonation frequency CKNK is, the larger the fuel supply amount is, and the detonation frequency CCK is increased.
As KNK decreases, the increase in fuel supply is reduced, and in the region where the detonation frequency CKNK is lower,
This is because the fuel supply amount can be gradually reduced.

As described above, in the fuel injection pulse width calculation process shown in FIG. 4, the correction value KKN for the basic pulse width is calculated.
Is calculated based on the detonation frequency CKNK obtained from the result of determination instead of the result of determination of detonation. For this reason, when detonation occurs, the fuel supply amount can be increased and corrected by an amount corresponding to the occurrence frequency, and the occurrence frequency of detonation can be controlled to a target value.

Therefore, if the ECU 20 executes the fuel injection pulse width calculation processing, it is possible not only to prevent the engine 1 from entering the detonation circulation process from knocking to seizure,
While preventing such detonation from occurring, it is possible to reduce the amount of fuel supplied to the engine 1 and to operate the engine 1 more optimally.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating an engine of an embodiment and peripheral devices thereof.

FIG. 2 is a flowchart illustrating a fuel injection pulse width calculation process.

FIG. 3 is a flowchart illustrating a fuel injection pulse width calculation / ignition timing calculation process.

FIG. 4 is a flowchart showing a modification of the fuel injection pulse width calculation processing shown in FIG.

FIG. 5 is an explanatory diagram illustrating an example of a map used in the calculation processing illustrated in FIGS.

FIG. 6 is an explanatory diagram showing a relationship between an air-fuel ratio and a detonation frequency in a two-cycle engine.

[Explanation of symbols]

1 ... engine, 2 ... scavenging port, 3 ... crankcase, 4 ...
Spark plug, 5 ... reed valve, 6 ... throttle valve, 1
0: throttle opening sensor, 11: crank angle sensor,
12: In-cylinder pressure sensor, 13: Intake air temperature sensor, 14: Atmospheric pressure sensor, 15: Injector, 20: ECU (engine control unit).

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) F02P 5/152 F02P 5/15 D 5/153 F term (reference) 3G022 AA02 DA02 EA02 GA01 GA05 GA08 GA11 GA14 GA15 3G084 AA02 BA13 BA17 DA01 DA02 DA38 FA01 FA02 FA10 FA21 FA33 FA38 3G301 HA01 HA03 JA01 JA02 JA22 LA00 MA14 NA08 NE01 NE06 PA09Z PA10Z PA11Z PC01Z PC06Z PE01Z PE03Z

Claims (5)

[Claims] 1. A fuel supply amount setting means for setting a fuel supply amount based on an operation state of a two-cycle engine, and supplying fuel to the two-cycle engine at a fuel supply amount set by the fuel supply amount setting means. A fuel supply means, comprising: a detonation detection means for detecting a detonation that self-surface ignites due to a rise in the surface temperature of the combustion chamber; and wherein the detonation is detected by the detonation detection means. 2. A two-stroke engine control device comprising: a fuel correcting means for increasing and correcting a fuel supply amount from a fuel supplying means. 2. The fuel correction means increases a correction amount for the fuel supply amount by a predetermined increase correction amount when detonation is detected by the detonation detection means. Correction amount updating means for reducing the correction amount for the amount by a reduction correction amount smaller than the increase correction amount, wherein the fuel supply amount setting unit sets the correction amount based on the correction amount set by the correction amount updating unit. 2. The fuel supply device according to claim 1, wherein the corrected fuel supply amount is corrected, and the fuel supply by the fuel supply unit is executed based on the corrected fuel supply amount.
The two-stroke engine control device according to claim 1. 3. The detonation occurrence frequency calculated by the detonation occurrence frequency calculated by the fuel correction means, the detonation occurrence frequency calculated by the detonation detection result by the detonation detection means, Correction amount setting means for setting a correction amount for the fuel supply amount so that the fuel supply amount increases as the occurrence frequency increases, and the fuel correction amount set by the correction amount setting means 2. The fuel supply device according to claim 1, wherein the fuel supply amount set by the fuel supply amount setting means is corrected based on the fuel supply amount, and the fuel supply by the fuel supply means is executed with the corrected fuel supply amount. Cycle engine control device. 4. An ignition timing setting means for setting an ignition timing based on an operation state of the two-stroke engine; an ignition means for spark-discharging a spark plug at an ignition timing set by the ignition timing setting means; 2. A two-stroke engine control device according to claim 1, further comprising: ignition timing retarding means for retarding the ignition timing by said ignition means when detonation is detected by said means. 5. A detonation detecting means, comprising: a detecting element for detecting a vibration of a two-stroke engine; a threshold setting means for setting a detonation determining threshold based on a rotation speed of the two-stroke engine; Judging means for comparing a detection signal from a detection element with a threshold value set by the threshold value setting means, and judging occurrence of detonation when the detection signal exceeds the threshold value. The two-stroke engine control device according to claim 1, wherein: