KR102119865B1 - Misfire diagnosis method and device of single cylinder four-stroke engine - Google Patents

Abstract

Disclosed are a misfire diagnosis method and device for determining a misfire occurring in a single-cylinder four-stroke engine using a tooth time signal (a time required for an engine crankshaft to rotate at a certain angle). According to one embodiment of the present invention, the misfire diagnosis method for a single-cylinder four-stroke engine comprises: a signal collection step of collecting tooth time signals output by a crankshaft position sensor during one engine cycle; a speed trend line generation step of extracting an engine speed (TDC1) at the beginning of an intake stroke and an engine speed (TDC3) at the end of an exhaust stroke from the collected tooth time signals, and generating a speed trend line (L1) using the extracted two engine speeds; a speed increase/decrease trend line generation step of extracting and engine speed (BDC1) at the beginning of a compression stroke and an engine speed (BDC2) at the end of an explosion stroke from the collected tooth time signals, and generating a speed increase/decrease trend line (L2) using the extracted two engine speeds; a linear trend removal step of removing a linear trend using the speed trend line (L1) so that the engine speed (TDC1) at the beginning of the intake stroke and the engine speed (TDC3) at the end of the exhaust stroke can become the same; and a misfire diagnosis step of determining whether there is a misfire by analyzing an inclination of the speed increase/decrease trend line (L2) to the speed trend line (L1) after the removal of the linear trend.

Description

Misfire diagnosis method and device of single cylinder four-stroke engine}

The present invention relates to a misfire diagnosis method and apparatus for a single cylinder four-stroke engine, and to a misfire diagnosis method and apparatus for a single cylinder four-stroke engine for diagnosing misfire from engine speed change in one engine cycle.

Misfire is a phenomenon in which fuel injected from an engine using fossil fuel does not burn and is discharged to the outside air as it is. When an engine misfire occurs, unburned fuel is discharged as it is, adversely affecting air pollution, or unburned fuel may be burned in the catalyst and damage the catalyst.

Accordingly, in the case of a general vehicle, the misfire detection logic is installed in the ECU to diagnose misfire to prevent air pollution or catalyst damage. An engine roughness method for diagnosing misfires by extracting an engine speed from a tooth time signal measured by a crankshaft position sensor is mainly applied to automobiles.

In addition, a technique for determining misfire by measuring the ionic current of a combustion pressure sensor or an ignition plug is also known.

On the other hand, in the global trend in which exhaust emission regulations are being strengthened day by day, two-wheeled motorcycles, which were not previously included in the regulation, are also not free from exhaust emission regulations. Therefore, two-wheeled motorcycles are also in the market to meet emission regulations. There is a need for technical supplementation to meet the needs.

One of the countermeasures to meet the demands of this market is the attempt to apply the true-fire detection technology that has been applied to general automobiles to motorcycles. However, it is difficult to apply the true fire detection technology applied to a general vehicle to a motorcycle.

In general, misfire detection technology applied to automobiles includes a fairly complicated process due to the characteristics of a multi-cylinder engine, and ECUs generally mounted on two-wheeled motorcycles are inexpensive and have low processing performance compared to automobiles. Therefore, it is difficult to apply the true detection technology of automobiles to ECUs of motorcycles.

Accordingly, in accordance with the market demand according to the exhaust emission regulations that are being strengthened worldwide, there is a need for a true fire detection technology suitable for the characteristics of two-wheeled motorcycles. In other words, a simple and optimized technique for accurately detecting/detecting misfires optimized for two-wheeled motorcycles is needed.

Korea Registered Patent No. 10-1869324 (Registration Date 2018.06.14)

The technical problem to be solved by the present invention is to provide a method and apparatus for diagnosing misfires of a single-stroke four-stroke engine that can diagnose/detect misfires simply and accurately compared to misfire detection technologies of automobile multi-cylinder engines.

According to an aspect of the present invention as a solution to the problem,

As a method of diagnosing misfires occurring in a single-stroke four-stroke engine using a tooth time signal (time required for the engine crankshaft to rotate at a certain angle) output by the crankshaft position sensor,

a) a signal collection step of collecting a tooth time signal output by the crankshaft position sensor during one engine cycle;

b) Speed trend line generation step of extracting the engine speed (TDC1) at the beginning of the intake stroke and the engine speed (TDC3) at the end of the exhaust stroke from the collected tooth time signal and generating a speed trend line (L1) using the two extracted engine speeds ;

c) A speed-and-deceleration trend line that extracts the engine speed (BDC1) at the beginning of the compression stroke and the engine speed (BDC2) at the end of the explosive stroke from the collected tooth time signal and generates a speed-deceleration trend line (L2) using the two extracted engine speeds. Creation step;

d) a linear trend removal step of removing a linear trend using the speed trend line L1 such that the engine speed TDC1 at the beginning of the intake stroke and the engine speed TDC3 at the end of the exhaust stroke are the same; And

e) after the removal of the linear trend, a misfire diagnosis step of diagnosing a misfire by analyzing the slope of the speed-acceleration trend line L2 relative to the speed trend line L1; and providing a misfire diagnosis method of the short-term four-stroke engine do.

Here, the one engine cycle may be an engine cycle including each stroke once in the order of intake-compression-explosion-exhaust.

In step b), the speed trend line L1 is the initial engine speed TDC1 of the intake stroke and the end engine speed TDC3 of the exhaust stroke, which are two different points on the engine speed curve generated from the tooth time signal. It can be a straight line passing by.

In addition, in step c), the speed increasing/decreasing trend line L2 indicates the engine speed (BDC1) at the beginning of the compression stroke and the engine speed (BDC2) at the end of the explosive stroke, which are two different points on the engine speed curve generated from the tooth time signal. It can be a straight line passing by.

In addition, in step d), the speed trend line is removed from all the tooth time signals in one engine cycle so that the engine speed at the beginning of the intake stroke and the engine speed at the end of the exhaust stroke are the same.

In step e), if the slope of the speed-acceleration trend line L2 with respect to the speed trend line L1 is negative after the removal of the linear trend, it may be diagnosed as a true story.

In addition, in step e), if the slope of the speed-increasing trend line L2 with respect to the speed trend line L1 after the linear trend removal is smaller than a threshold mapped to a memory, it may be diagnosed as a misfire.

According to another aspect of the present invention as a solution to the problem,

As a device for diagnosing misfires occurring in single-stroke 4-stroke engines,

A crankshaft position sensor disposed around a target wheel of the engine crankshaft to generate a tooth time signal required for calculating engine speed;

Includes a controller for analyzing engine speed change of one engine cycle from a tooth time signal of the crankshaft position sensor and diagnosing misfire using the analysis result.

The controller,

A signal collection unit for collecting the tooth time signal output by the crankshaft position sensor during one engine cycle;

Using the collected tooth time signal, the engine speed (TDC1) at the beginning of the intake stroke and the engine speed (TDC3) at the end of the exhaust stroke are extracted in one engine cycle, and the speed trend line (L1) is generated using the two extracted engine speeds. And a speed trend line generator

A speed-deceleration trend line generator that extracts the engine speed (BDC1) at the beginning of the compression stroke and the engine speed (BDC2) at the end of the explosive stroke from the collected tooth time signal and generates a speed-deceleration trend line (L2) using the two extracted engine speeds. Wow,

A linear trend removing unit that removes a linear trend using the speed trend line L1 so that the engine speed TDC1 at the beginning of the intake stroke and the engine speed TDC3 at the end of the exhaust stroke are the same;

After the removal of the linear trend, a misfire diagnosis device for a single-stroke four-stroke engine comprising a misfire diagnosis unit that diagnoses a misfire by analyzing the slope of the speed-acceleration trend line (L2) relative to the speed trend line (L1) to provide.

Here, the speed trend line generation unit generates an engine speed curve defined as an engine speed change with respect to a change in the rotational angle of the engine crankshaft using the tooth time signal, and is displayed as two different points on the generated engine speed curve. The speed trend line L1 may be generated by connecting the initial engine speed TDC1 of the intake stroke and the terminal engine speed TDC3 of the exhaust stroke in a straight line.

In addition, the speed increasing/decreasing trend line generating unit generates an engine speed curve defined as an engine speed change with respect to a change in the rotational angle of the engine crankshaft using the tooth time signal, and is displayed as two different points on the generated engine speed curve. The speed acceleration/deceleration trend line L2 may be generated by connecting the engine speed BDC1 at the beginning of the compression stroke and the engine speed BDC2 at the end of the explosive stroke in a straight line.

In addition, the linear trend removing unit may remove the speed trend line from all tooth time signals in one engine cycle so that the engine speed at the beginning of the intake stroke and the engine speed at the end of the exhaust stroke are the same.

In addition, the misdiagnosis unit may diagnose a misfire if the slope of the velocity-accelerated trend line L2 with respect to the velocity trend line L1 is negative after the linear trend is removed.

In addition, if the slope of the velocity-accelerated trend line L2 with respect to the velocity trend line L1 is less than a threshold mapped to a memory device, the misdiagnosis unit may diagnose the misfire as a result of removing the linear trend.

According to an embodiment of the present invention, in the engine cycle subject to misfire analysis, some information about engine characteristics capable of clearly distinguishing between normal ignition and misfire (intake stroke initial engine speed, exhaust stroke end engine speed, compression stroke initial engine speed And the engine speed at the end of the explosive stroke), and calculate the slope from the extracted result and analyze it to diagnose whether it is a misfire.

In other words, by diagnosing/detecting misfires with only the minimum key information that can clearly determine whether a misfire has occurred, it is possible to simplify the process for misdiagnosis/detection while enabling high-precision misdiagnosis/detection. It is possible to provide an optimized misfire detection function suitable for the situation of a two-wheeled motorcycle in which a low-cost ECU is adopted compared to an expensive ECU.

In addition, in the global trend of exhaust emission regulation being strengthened day by day, it is possible to meet the market demand to meet exhaust emission regulation for two-wheeled motorcycles that have not been previously regulated, and additional hardware Since it can be implemented only with software without additional configuration, the development cost is also low.

1 is a conceptual diagram of a four-stroke engine misfire diagnosis device according to an embodiment of the present invention.
Figure 2 is a view for explaining the process of generating a speed trend line and a speed trend line.
3 is a view showing an engine speed curve during normal ignition and misfire after linear detrend.
Figure 5 is a flow chart for explaining the misfire diagnosis method of a single-stroke four-stroke engine according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

In describing the present invention, terms used in the following specification are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise.

Also, in this specification, the terms “include” or “have” are intended to indicate that there are features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and one or more other. It should be understood that features or numbers, steps, operations, components, parts or combinations thereof are not excluded in advance.

Further, terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from other components.

In addition, terms such as “…unit”, “…unit”, and “…module” described in the specification mean a unit that processes at least one function or operation, which may be implemented by hardware or software or a combination of hardware and software. You can.

In the description with reference to the accompanying drawings, the same reference numerals will be assigned to the same components, and duplicate descriptions of the same components will be omitted. In the following description, when it is determined that the detailed description of known technologies related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted.

Hereinafter, the meaning of the main terms used in describing the embodiments of the present invention will be briefly described.

An engine cycle of one of the terms used below is an engine cycle that includes intake, compression, explosion, and exhaust strokes one at a time, and refers to a section in which the engine crankshaft rotates two wheels (720ㅀ), and the speed trend line is the crankshaft. It may be defined as a straight line passing through the initial engine speed TDC1 of the intake stroke and the end engine speed TDC3 of the exhaust stroke, which are two different points on the engine speed curve generated from the tooth time signal of the position sensor.

In addition, the trend line of acceleration/deceleration is a straight line passing through the engine speed (BDC1) at the beginning of the compression stroke and the engine speed (BDC2) at the end of the explosive stroke, which are two different points on the engine speed curve generated from the tooth time signal of the crankshaft position sensor. Means, where the tooth time (Tooth time) refers to the time required for the engine crankshaft to rotate a certain angle.

1 is a conceptual diagram of a four-stroke engine misfire diagnosis apparatus according to an embodiment of the present invention, with reference to FIG. 1 will be described with respect to the single-stroke four-stroke engine misfire diagnosis apparatus according to an embodiment of the present invention.

Referring to FIG. 1, a misfire diagnosis apparatus for a single-stroke four-stroke engine according to an embodiment of the present invention includes a crankshaft position sensor 10 and a controller 20. The controller 20 may be an ECU, and the crankshaft position sensor 10 is disposed around a target wheel 40 on the engine crankshaft 30 and calculates engine speed according to the rotation of the target wheel 40. The required Tooth Time signal is generated.

A plurality of teeth are formed on the outer circumferential surface of the target wheel 40 to measure the angular velocity of the crankshaft 30, and the crankshaft position sensor 20 is rotated when the target wheel 40 rotates. The controller 20 calculates the angular speed of the engine crankshaft 30 using the time information for detecting the tooth. Then, the engine speed is calculated from the calculated angular speed.

The controller 20 controls the engine speed by controlling the energized state of the fuel injector 60 and the ignition coil 50 in accordance with the driver's acceleration or deceleration demand through hand accelerator operation (not shown), as well as controlling the engine speed. From the tooth time signal of the position sensor 10, the engine speed change of one engine cycle, which is an object of misfire analysis, is analyzed. In addition, diagnosis of misfire is diagnosed using the analysis result.

Misfire, as mentioned earlier, refers to a phenomenon in which fuel injected into an engine cylinder does not combust and is discharged into the outside air. When a misfire occurs, the periodicity of the signal of the tooth time (the time it takes for the engine crankshaft to rotate at a certain angle) is impaired because no energy source accelerating the engine speed is generated in the explosion (or expansion) stroke.

Misfire appears as unburned fuel in the explosive stroke→not generating combustion pressure→reducing piston speed→reducing crankshaft rotation momentum, which results in longer tooth time and, conversely, reduced engine speed. That is, when a misfire occurs, the energy source that drives the engine is not generated, so the engine speed decreases. Therefore, by analyzing the engine speed in one engine cycle, it is possible to diagnose whether the misfire occurs.

The present invention is to enable accurate and rapid diagnosis/detection of misfires occurring in a single-stroke four-stroke engine using the characteristics of changes in engine speed that appear during misfires. To this end, the controller 20 applied to the present embodiment, It includes a signal collection unit 22 and a speed trend line generation unit 24. It also includes a speed-and-decreasing trend line generating unit 25, a linear trend removing unit 26, and a true story diagnosis unit 28.

The configuration of each part constituting the controller will be described in more detail.

The signal collection unit 22 collects a tooth time signal output by the crankshaft position sensor 10 during one engine cycle. More specifically, when the target wheel 40 is rotated, the crankshaft position sensor 10 detects the value of the circumferential surface of the target wheel 40 to generate a tooth time signal, and the generated tooth time signal is generated by the signal collection unit 22 ), the signal collection unit 22 collects information necessary for engine speed analysis.

The tooth time signal collected by the signal collection unit 22 is provided to the speed trend line generation unit 24, and the speed trend line generation unit 24 uses the received tooth time signal to transmit the engine speed of a specific stroke within one engine cycle. Extract (calculate) Specifically, the engine speed at the beginning of the intake stroke and the engine speed at the end of the exhaust stroke are extracted in one engine cycle. Then, a speed trend line is generated using the two extracted engine speeds.

The speed increasing/decreasing trend line generating unit 25 also extracts (calculates) the engine speed of a specific stroke in one engine cycle using the tooth time signal provided by the signal collecting unit 22. Specifically, the engine speed at the beginning of the compression stroke and the engine speed at the end of the explosion stroke are extracted in one engine cycle. Then, using the two extracted engine speeds, a speed-increasing trend line is generated.

Referring to FIG. 2, the process of generating the speed trend line and the speed trend line will be briefly described.

FIG. 2 is an exemplary view for explaining the process of generating the speed trend line and the speed trend line, and is a view for explaining the process of generating the speed trend line and the speed trend line during normal ignition and misfire in the constant acceleration situation.

Referring to FIG. 2, each of the speed trend line L1 and the speed acceleration/deceleration trend line L2 is the initial engine speed TDC1 of the intake stroke and the end engine speed of the exhaust stroke, which are two points on the engine speed curve generated from the tooth time signal. TDC3) means a straight line (L1) and another two points on the engine speed curve: the initial engine speed (BDC1) at the beginning of the compression stroke and the straight line (L2) at the end of the explosive stroke (BDC2).

The speed trend line L1 and the speed acceleration/deceleration trend line L2 generate an engine speed curve (a curve indicating a change in engine speed according to a change in the rotation angle of the crankshaft) from the tooth time signal, and a tooth time on the generated engine speed curve. It can be generated by finding the TDC1, TDC2, BDC1, and BDC2 from the signal input sequence or the rotation angle of the crankshaft 30, and connecting TDC1 and TDC3, BDC1 and BDC2 in a straight line.

On the other hand, the operation of adjusting the slope of the speed trend line to zero (0) so that the engine speed TDC1 at the beginning of the intake stroke and the engine speed TDC3 at the end of the exhaust stroke are the same is performed through the linear trend removing unit 26. do. The linear trend removing unit 26 removes the linear trend from the tooth time signals output by the crankshaft position sensor 10 using the speed trend line generated by the speed trend line generating unit 24 (Linear Detrend).

When the speed trend line is removed from all tooth time signals in one engine cycle, a linear trend elimination effect occurs in which the engine speed TDC1 at the beginning of the intake stroke and the engine speed TDC3 at the end of the exhaust stroke are the same. Here, the speed trend line L1 is a line connecting the TDC1, which is the inlet engine speed of one cycle, and the TDC3, which is the exit engine speed, and thus may be an average engine speed in one cycle.

Therefore, if the tooth time average value corresponding to the engine speed average value is subtracted from all the tooth time signals in one engine cycle, the engine speed (TDC1) at the beginning of the intake stroke and the engine speed at the end of the exhaust stroke from the engine speed curve (see FIG. 2). (TDC3) is the same, that is, the slope of the velocity trend line L1 is zero, so that a linear trend elimination effect occurs.

FIG. 3 is a diagram showing the engine speed curve during normal ignition and misfire after Linear Detrend.

Referring to FIG. 3, in normal ignition, an energy source accelerating the engine speed is generated in the explosive stroke, and therefore, the speed of the acceleration/deceleration trend line L2 with respect to the speed trend line L1 whose slope becomes zero (0) after removing the linear trend While the slope has a positive value (positive number), since there is no energy addition due to an explosion in the true story, the slope of the speed-accelerating trend line L2 appears to be similar to or smaller than the slope of the speed trend line (L1).

Therefore, by analyzing the slope of the speed increasing/decreasing trend line L2 with respect to the speed trend line L1 where the slope has become zero (0) after linear trend removal, it is possible to diagnose whether a misfire has occurred. The present invention is to diagnose whether a misfire is made by using a point in which the slope of the speed-acceleration trend line L2 is markedly different depending on whether misfire occurs.

After the linear trend removal (Linear Detrend), the misdiagnosis unit 28 performs the task of determining the slope of the velocity-accelerated trend line L2 with respect to the velocity trend line L1 and analyzing the obtained slope to diagnose whether it is misfire. do. The misfire diagnosis unit 28 may diagnose the misfire by comparing the slope of the speed acceleration/deceleration trend line L2 with respect to the speed trend line L1 with a threshold mapped to the storage device.

Here, the map data to which the threshold value is mapped is obtained by obtaining the slope of the speed increasing/decreasing trend line (L2) with respect to the speed trend line (L1) during normal ignition and misfire for each load band, and analyzing the obtained value to analyze the calculated load band It may be that the slope of the speed-adjusting trend line L2 at the point that is the boundary between star misfire and normal ignition is selected as a threshold value, and data may be obtained in a matrix form for two factors, engine speed and load band.

The misfire diagnosis unit 28 desirably matches the situation (engine load and engine speed) when the slope of the speed increasing/decreasing trend line L2 is obtained, and recalls a previously stored threshold and compares it with the calculated slope. As a result, if the slope of the speed-adjusting trend line L2 is less than a threshold, a process of diagnosing as a misfire may be included.

In some cases, if the slope of the speed-adjusting trend line L2 is similar to the slope of the speed trend line L1, the misfire is diagnosed by comparing the magnitude with the threshold as described above, and the speed with respect to the speed trend line L1 If the slope of the subtractive trend line L2 is negative (if the slope sign is negative (-)), it may include a process of unconditionally diagnosing it without comparison with a threshold.

Hereinafter, the misfire diagnosis process in the single-cylinder four-stroke engine misfire diagnosis apparatus described above will be described with reference to the flowchart of FIG. 5.

4 is a flow chart for explaining a method for diagnosing misfires in a single-stroke four-stroke engine according to an embodiment of the present invention. For convenience of description, the configuration shown in FIG. 1 described above will be described by referring to the corresponding reference number.

Referring to FIG. 4, a misfire diagnosis method in a single-stroke four-stroke engine according to an embodiment of the present invention includes a signal collection step (S100), a speed trend line generation step (S200), and a speed-acceleration trend line generation step (S300), a linear trend It includes a removal step (S400) and a misfire diagnosis step (S500). Hereinafter, the operation or processing performed in each step will be described in detail.

In the signal collection step (S100), the tooth time signal output by the crankshaft position sensor 10 is collected according to the rotation of the target wheel 40 during one engine cycle. The signal collection step (S100) includes a down sampling process to reduce the amount of signal data to process by processing the tooth time signal of the crankshaft position sensor 10 at regular intervals, thereby greatly reducing the computational load that the controller must bear. Can be. In this case, the maximum downsampling is the case of collecting the tooth time signal at only four locations, TDC1, BDC1, TDC2 and BDC2.

In the speed trend line generation step S200, the engine speed of a specific stroke in one engine cycle is extracted (calculated) using the tooth time signal collected in the signal collection step S100. Specifically, the engine speed (TDC1) at the beginning of the intake stroke and the engine speed (TDC3) at the end of the exhaust stroke are extracted from one engine cycle using the tooth time signal, and the speed trend line (L1) is used using the two extracted engine speeds. Produces

The speed trend line L1 in the speed trend line generation step S200 preferably generates an engine speed curve from a tooth time signal output by the crankshaft position sensor 10 in one engine cycle to be analyzed, and the generated engine It can be generated by linearly connecting the engine speed TDC1 at the beginning of the intake stroke on the speed curve and the engine speed TDC3 at the end of the exhaust stroke.

In the step of generating the speed-adjusting trend line (S300), the engine speed of a specific stroke in one engine cycle is extracted (calculated) by using the tooth time signal collected in the signal collection step (S100). Specifically, the engine speed (BDC1) at the beginning of the compression stroke and the engine speed (BDC2) at the end of the explosive stroke are extracted from one engine cycle using the tooth time signal, and the speed-up/down trend line (L2) is used using the two extracted engine speeds. ).

In the same manner as the speed trend line, the speed trend line L2 in the step of generating a speed trend line is also the same as the speed trend line, in the initial stage of compression on the engine speed curve (curve showing a change in engine speed according to a change in the rotation angle of the crankshaft). It can be generated by linearly connecting the engine speed BDC1 and the end engine speed TDC3 of the exhaust stroke.

After the step of generating the acceleration/deceleration trend line (S300), the engine speed (TDC1) at the beginning of the intake stroke and the engine speed (TDC3) at the end of the exhaust stroke are equal on the engine speed curve so that the slope of the speed trend line (L1) becomes zero (0). The linear trend elimination step (S400) is performed. In step S400, the linear trend is removed from the tooth time signals output from the crankshaft position sensor 10 using the speed trend line L1.

When the speed trend line is removed from all tooth time signals in one engine cycle, a linear trend elimination effect occurs in which the engine speed TDC1 at the beginning of the intake stroke and the engine speed TDC3 at the end of the exhaust stroke are the same. Here, the speed trend line L1 is a line connecting the TDC1, which is the inlet engine speed of one cycle, and the TDC3, which is the exit engine speed, and thus may be an average engine speed in one cycle.

Therefore, if the tooth time average value corresponding to the engine speed average value is subtracted from all the tooth time signals in one engine cycle, the engine speed (TDC1) at the beginning of the intake stroke and the engine speed at the end of the exhaust stroke from the engine speed curve (see FIG. 2). (TDC3) is the same, that is, the slope of the velocity trend line L1 is zero, so that a linear trend elimination effect occurs.

Since in normal ignition, an energy source accelerating the engine speed is generated in the explosive stroke, the slope of the speed-accelerating trend line L2 is positive for the speed trend line L1 where the slope becomes zero (0) after removing the linear trend. On the other hand, since there is no energy addition due to explosion in the true story, the slope of the speed-acceleration trend line L2 is similar to or smaller than the slope of the speed trend line L1 (negative number).

Therefore, by analyzing the slope of the speed increasing/decreasing trend line L2 with respect to the speed trend line L1 where the slope has become zero (0) after linear trend removal, it is possible to diagnose whether a misfire has occurred. In the misfire diagnosis step (S500), whether the misfire occurs is accurately diagnosed by using a point in which the slope of the speed-acceleration trend line L2 is markedly different depending on whether misfire occurs.

After the linear trend removal (Linear Detrend), the operation of determining the slope of the speed-adjusting trend line (L2) with respect to the speed trend line (L1) and analyzing the obtained slope to diagnose whether it is misfire (Misfire) is performed in the misfire diagnosis step (S500). . In step S500, preferably, the slope of the speed increasing/decreasing trend line L2 with respect to the speed trend line L1 may be compared with a threshold mapped to the storage device to diagnose whether the fire is misfire.

Here, the map data to which the threshold value is mapped is obtained by obtaining the slope of the speed increasing/decreasing trend line (L2) with respect to the speed trend line (L1) during normal ignition and misfire for each load band, and analyzing the obtained value to analyze the calculated load band It may be that the slope of the speed-adjusting trend line L2 at a point that is the boundary between star misfire and normal ignition is selected as a threshold value, and data may be obtained in a matrix form for two factors, engine speed and load band.

In step S500, preferably, when the slope of the speed increasing/decreasing trend line L2 with respect to the speed vertebral line L1 is obtained, it is matched to the situation (engine load and engine speed), and a pre-stored threshold is called to obtain the slope and When comparing and comparing, if the slope of the speed-adjusting trend line L2 is smaller than a threshold, a process of diagnosing misfire may be included.

In some cases, if the slope of the speed-adjusting trend line L2 is similar to the slope of the speed trend line L1, the misfire is diagnosed by comparing the magnitude with the threshold as described above, and the speed with respect to the speed trend line L1 If the slope of the subtractive trend line L2 is negative (if the slope sign is negative (-)), it may include a process of unconditionally diagnosing without comparing with a threshold.

According to the embodiment of the present invention described above, in the engine cycle subject to misfire analysis, some information about engine characteristics that can clearly distinguish between normal ignition and misfire (intake stroke initial engine speed, exhaust stroke end engine speed, compression stroke initial The engine speed and the engine speed at the end of the explosive stroke) are extracted, and the slope is calculated from the extracted result and analyzed to diagnose whether it is a misfire.

In other words, by diagnosing/detecting misfires with only the minimum key information that can clearly determine whether a misfire has occurred, it is possible to simplify the process for misdiagnosis/detection while enabling high-precision misdiagnosis/detection. It is possible to provide an optimized misfire detection function suitable for the situation of a two-wheeled motorcycle in which a low-cost ECU is adopted compared to an expensive ECU.

In addition, in the global trend of exhaust emission regulation being strengthened day by day, it is possible to meet the market demand to meet exhaust emission regulation for two-wheeled motorcycles that have not been previously regulated, and additional hardware Since it can be implemented only with software without additional configuration, the development cost is also low.

In the detailed description of the present invention described above, only specific embodiments thereof have been described. However, it should be understood that the present invention is not limited to the specific forms mentioned in the detailed description, but rather includes all modifications, equivalents, and substitutes within the spirit and scope of the present invention as defined by the appended claims. Should be.

10: crankshaft position sensor
20: controller
22: signal collection unit
24: speed trend line generator
25: speed trend line generator
26: linear trend removal unit
28: true story diagnosis
30: crankshaft
40: target wheel
50: ignition coil
60: fuel injector

Claims (12)

As a method of diagnosing misfires occurring in a single-stroke four-stroke engine using a tooth time signal (time required for the engine crankshaft to rotate at a certain angle) output by the crankshaft position sensor,
a) a signal collection step of collecting a tooth time signal output by the crankshaft position sensor during one engine cycle;
b) Speed trend line generation step of extracting the engine speed (TDC1) at the beginning of the intake stroke and the engine speed (TDC3) at the end of the exhaust stroke from the collected tooth time signal and generating a speed trend line (L1) using the two extracted engine speeds ;
c) A speed-and-deceleration trend line that extracts the engine speed (BDC1) at the beginning of the compression stroke and the engine speed (BDC2) at the end of the explosive stroke from the collected tooth time signal and generates a speed-deceleration trend line (L2) using the two extracted engine speeds. Creation step;
d) a linear trend removal step of removing a linear trend using the speed trend line L1 such that the engine speed TDC1 at the beginning of the intake stroke and the engine speed TDC3 at the end of the exhaust stroke are the same; And
e) a misfire diagnosis step of diagnosing misfire by analyzing the slope of the speed-declining trend line L2 with respect to the speed trend line L1 after removing the linear trend; a misfire diagnosis method of the short-term four-stroke engine.
According to claim 1,
In step b), the speed trend line L1 is
Misdiagnosis diagnosis of a single-stroke four-stroke engine characterized by a straight line passing through the initial engine speed (TDC1) of the intake stroke and the end engine speed (TDC3) of the exhaust stroke, which are two different points on the engine speed curve generated from the tooth time signal. Way.
According to claim 1,
In step c), the speed trend line L2 is
Misdiagnosis of a single-stroke four-stroke engine characterized by a straight line passing through the engine speed (BDC1) at the beginning of the compression stroke and the engine speed (BDC2) at the end of the explosion stroke, which are two different points on the engine speed curve generated from the tooth time signal. Way.
According to claim 1,
In step d),
A method for diagnosing misfire of a single-stroke four-stroke engine, wherein the speed trend line is removed from all tooth time signals in one engine cycle so that the engine speed at the beginning of the intake stroke and the engine speed at the end of the exhaust stroke are the same.
According to claim 1,
In step e),
A method for diagnosing misfires in a single-stroke four-stroke engine, characterized in that if the slope of the speed-accelerated trend line (L2) relative to the speed trend line (L1) is negative after removing the linear trend, it is diagnosed as misfire.
According to claim 1,
In step e),
After the linear trend is removed, if the slope of the speed increasing/decreasing trend line (L2) relative to the speed trend line (L1) is less than a threshold (Threshold) mapped to the storage device, the short-term four-stroke engine misfire diagnosis method characterized by diagnosing it as a misfire .
As a device for diagnosing misfires occurring in single-stroke four-stroke engines,
A crankshaft position sensor disposed around a target wheel of the engine crankshaft to generate a tooth time signal required for calculating engine speed;
Includes a controller for analyzing engine speed change of one engine cycle from a tooth time signal of the crankshaft position sensor and diagnosing misfire using the analysis result.
The controller,
A signal collection unit for collecting the tooth time signal output by the crankshaft position sensor during one engine cycle;
Using the collected tooth time signal, the engine speed (TDC1) at the beginning of the intake stroke and the engine speed (TDC3) at the end of the exhaust stroke are extracted in one engine cycle, and the speed trend line (L1) is generated using the two extracted engine speeds. And a speed trend line generator
A speed-deceleration trend line generator that extracts the engine speed (BDC1) at the beginning of the compression stroke and the engine speed (BDC2) at the end of the explosive stroke from the collected tooth time signal and generates a speed-deceleration trend line (L2) using the two extracted engine speeds. Wow,
A linear trend removing unit that removes a linear trend using the speed trend line L1 so that the engine speed TDC1 at the beginning of the intake stroke and the engine speed TDC3 at the end of the exhaust stroke are the same;
A misfire diagnosis device for a single-stroke four-stroke engine characterized by comprising a misfire diagnosis unit that diagnoses a misfire by analyzing the slope of the speed-deceleration trend line (L2) relative to the speed trend line (L1) after removing the linear trend.
The method of claim 7,
The speed trend line generation unit,
An engine speed curve defined as a change in engine speed with respect to a change in rotation angle of the engine crankshaft is generated using the tooth time signal,
A short-term cylinder characterized by generating the speed trend line by connecting the initial engine speed (TDC1) of the intake stroke and the end engine speed (TDC3) of the exhaust stroke in a straight line, represented by two different points on the generated engine speed curve. A four-stroke engine misfire diagnosis device.
The method of claim 7,
The speed trend line generator,
An engine speed curve defined as a change in engine speed with respect to a change in rotation angle of the engine crankshaft is generated using the tooth time signal,
Characterized in that the engine speed (BDC1) at the beginning of the compression stroke and the engine speed (BDC2) at the end of the explosive stroke are connected in a straight line to generate the speed-increasing trend line indicated by two different points on the generated engine speed curve. Misdiagnosis device for single-stroke four-stroke engine.
The method of claim 7,
The linear trend removing unit,
A misfire diagnosis device for a single-stroke four-stroke engine characterized in that the engine speed at the beginning of the intake stroke is equal to the engine speed at the end of the exhaust stroke by removing the speed trend line from all tooth time signals in one engine cycle.
The method of claim 7,
The misfire diagnosis unit,
A misfire diagnosis device for a single-stroke four-stroke engine, characterized in that if the slope of the speed-acceleration trend line (L2) relative to the speed trend line (L1) is negative after removing the linear trend, it is diagnosed as misfire.
The method of claim 7,
The misfire diagnosis unit,
After the linear trend is removed, if the slope of the speed-increasing trend line (L2) with respect to the speed trend line (L1) is less than a threshold (Threshold) mapped to the storage device, the misfire diagnosis device of the single-stroke four-stroke engine, characterized in that it is diagnosed as misfire .

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