JP3066004B1 - Misfire detection device for a multi-cylinder internal combustion engine for power generation - Google Patents

Abstract

Abstract: A misfire detection device capable of accurately measuring the amount of abnormal combustion and misfire of an engine at low cost and accurately by using a rotational speed detection sensor or the like and a generated power signal used in an electronic control engine. provide. SOLUTION: The rotational angular velocity of an output shaft of an internal combustion engine is measured, and an angular velocity variation Fn which is a difference between an average rotational angular velocity and a measured rotational angular velocity is obtained. Angular velocity variation reference Fs obtained in advance
And the angular velocity variation difference G based on the angular velocity variation Fn.
To derive the angular speed variation difference Da within the predetermined stroke, and to determine the misfire state of the internal combustion engine based on the angular speed variation difference Da, an abnormal variation other than the rotation variation due to the variation of the engine load. Misfire determination is performed based on the angular velocity variation difference Da representing the rotation variation, and the angular velocity variation reference Fs is updated according to the angular velocity variation difference Da in accordance with the criteria for the misfire determination.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to detecting a combustion failure and misfire of a multi-cylinder internal combustion engine for power generation.

[0002]

2. Description of the Related Art As a conventional device for detecting misfire of an internal combustion engine, a special sensor is attached to detect a combustion state,
There is a type in which a temperature sensor is attached near the exhaust port to determine a decrease in exhaust temperature at the time of misfire, or a type in which misfire is detected by detecting rotation fluctuation and detecting a decrease in rotation speed.

[0003]

According to the above-mentioned prior art, In the rotation fluctuation detection type misfire detection device, when the rotation angular velocity changes due to factors such as load fluctuation other than misfire,
This may be erroneously detected. 2. When a certain degree of operation is possible even when a misfire has occurred, as in the case of a generator engine, urgently stopping the engine and recovering from the failure lacks stability of power supply. In other words, it is necessary to rationally set the criteria. However, in a state where an engine failure or an accident occurs, the engine must be stopped even if the power supply is stopped. For this reason, an amount indicating the degree of misfire such as misfire or poor combustion (referred to as misfire amount in the present application)
It is necessary to use a value that depends on the explosive power of each cylinder as much as possible. If the absolute value of the rotation fluctuation is simply used, the explosive power normally generated for each load differs, so that the misfire amount cannot be directly estimated from the fluctuation amount. 3. In the rotation fluctuation detection, the tendency of the rotation fluctuation of the engine differs depending on the state of the load. Therefore, when the rotation fluctuation is detected by one method, the accuracy is good for one load, but may be poor for another load. This is because the rotational characteristics of the engine change depending on the load of the engine.
Also, a change in the engine speed affects the load side and further changes the load. For this reason, there is a drawback that the parameters required by the fixed analysis method alone become too large and it is difficult to cope with them.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a low-cost and accurate engine abnormal combustion and misfire by utilizing a rotational speed detection sensor and the like and a generated power signal used in an electronically controlled engine. It is an object of the present invention to provide a misfire detection device capable of measuring and determining the misfire.

[0005]

In order to achieve the above object, according to the present invention, the rotational angular velocity of an output shaft of an internal combustion engine is determined by:
Corresponding to the rotation angle at each point in time of the measurement, an angular velocity measuring means for measuring as a waveform is provided, and an average rotational angular velocity and a rotational angular velocity measured by the angular velocity measuring means for a certain period before the measurement time point for measuring the rotational angular velocity. The angular velocity fluctuation deriving means for deriving the difference between the angular velocity fluctuations Fn at each time point of the measurement and the rotation is normal.
In this state, the angular velocity variation reference F obtained in advance as a waveform corresponding to the rotation angle of the output shaft at each point in time of the measurement described above.
s and the angular velocity fluctuation amount Fn derived at each time of the measurement by the angular velocity fluctuation amount Fn, the angular velocity difference derivation means for obtaining the angular velocity fluctuation difference G, and the angular velocity fluctuation obtained by the angular velocity difference derivation means Based on the difference G,
A misfire detection device for a multi-cylinder internal combustion engine for power generation, comprising: misfire determination means for determining a misfire state of the internal combustion engine based on the difference in angular speed Da while deriving an angular speed variation difference Da within a predetermined stroke. As described in claim 1, the characteristic configuration includes a load condition measuring unit that measures a load of the internal combustion engine at each time point of the measurement from generated power, and the misfire determination unit determines a change in the load. The angular velocity fluctuation difference D representing the rotation fluctuation, excluding the rotation fluctuation due to
According to a, a misfire discrimination is performed, and a fluctuation reference updating means for updating the angular velocity fluctuation reference Fs in accordance with the angular velocity fluctuation difference Da in accordance with the reference of the misfire determination is provided. In this device configuration, misfire determination is performed on the basis of angular velocity. In this determination, a load situation measuring means is provided, and misfire determination is performed in consideration of the load fluctuation obtained from this means. By doing so, it is possible to eliminate the influence of the load fluctuation in the misfire determination. Further, the angular velocity variation reference Fs necessary for obtaining the angular velocity variation difference G serving as basic data for misfire determination is sequentially updated by the variation reference updating means. Therefore, for example, after determining that there is no difference in rotational angular speed due to abnormal rotation, it is possible to adopt a structure in which the angular speed variation standard Fs is updated, and this angular speed variation standard Fs is determined to match the actual situation of the engine. can do.

According to the present invention, there is provided an angular velocity measuring means for measuring a rotational angular velocity of an output shaft of an internal combustion engine as a waveform corresponding to a rotational angle at each measurement time. The angular velocity variation deriving means for deriving the difference between the average rotational angular velocity for a certain period of time before the measurement time point and the rotational angular velocity measured by the angular velocity measuring means as the angular velocity variation Fn at each measurement time, In a state where it is clear that the rotation is normal , in correspondence with the rotation angle of the output shaft at each time point of the measurement, an angular velocity variation reference Fs previously obtained as a waveform, and at each time point of the measurement time An angular velocity difference deriving means for obtaining an angular velocity variation difference G based on the angular velocity variation Fn derived by the angular velocity variation deriving means; A power generating multi-cylinder including misfire discriminating means for deriving an angular velocity variation difference Da within a predetermined stroke based on the dynamic difference G and for determining a misfire state of the internal combustion engine based on the angular velocity variation difference Da. The characteristic configuration of the misfire detection device for an internal combustion engine includes a load condition measuring unit that measures a load of the internal combustion engine at each time of the measurement from generated power, as described in claim 2, and the angular velocity fluctuation. An amount reference Fs is a function of the load, and a variation reference updating means for updating the angular speed variation reference Fs in accordance with the angular speed variation difference Da is provided. In this case, the angular velocity fluctuation reference Fs is set as a function of the load, and the angular velocity fluctuation reference Fs is specified according to the load obtained by the load condition measuring means and is used for misfire detection. Can be satisfactorily performed in a state where the load fluctuation is excluded.

In the above configuration, as the angular velocity difference deriving means, the angular velocity difference deriving means may include the angular velocity variation reference Fs and the angular velocity variation deriving means derived at each measurement time. It is preferable to include a plurality of deriving units that have different procedures for obtaining the angular velocity fluctuation difference G based on the angular velocity fluctuation amount Fn. For example, as shown in Equation 5 below, in the method of deriving the angular velocity variation difference G according to the operating state of the internal combustion engine, it may be possible to better grasp the state of the internal combustion engine by making the method different. Preferably, a plurality of different methods are provided.

Further, as set forth in claim 4, the angular velocity difference deriving means includes an angular velocity variation reference F.
a first deriving unit that sets the difference between the angular velocity variation F and the angular velocity variation Fn to 0, and sets the angular velocity variation G to 0 when the angular velocity variation Fn is larger than the angular velocity variation reference Fs. When the angular velocity variation Fn is smaller than the angular velocity variation reference Fs, a second deriving unit that sets a difference between the angular velocity variation reference Fs and the angular velocity variation Fn to the angular velocity variation difference G The first deriving means and the second deriving means for determining the angular velocity variation difference Da.
The angular velocity variation difference G determined by the deriving means,
Distribution functions Ka, K depending on the load and corresponding to each deriving means
It is preferable that the angular velocity fluctuation difference Da is determined based on b. In this configuration, a plurality of deriving units are provided, and in deriving the angular velocity variation difference G,
Although it is possible to appropriately cope with the operation state of the internal combustion engine, it may be preferable to select which angular velocity fluctuation difference G is to be used for misfire determination depending on the load state. Therefore, in deriving the angular velocity variation difference Da, it depends on the load,
Based on the distribution functions Ka and Kb corresponding to each deriving means,
By obtaining the angular velocity variation difference Da, a more reliable misfire determination can be performed.

[0009] In order to configure the apparatus as described above, claim 5 is provided.
As described in the above, the misfire determination means can be configured to determine that a misfire has occurred when the angular velocity variation difference Da is larger than a predetermined angular velocity variation difference reference value Dt.

Further, according to a sixth aspect of the present invention, the angular velocity fluctuation in the fluctuation amount reference updating means is determined by a magnitude relationship between the angular velocity fluctuation difference Da and the angular velocity fluctuation difference reference value Dt. By changing the updating procedure of the quantity reference Fs, the angular velocity variation reference Fs can be updated accurately and easily according to the misfire determination.

The misfire detection of the multi-cylinder internal combustion engine for power generation has been described above. However, the misfire detection by the abnormal rotation detection excluding the fluctuation due to the load as described in the present application is realized by the configuration described in claim 7. it can. That is, the rotation angular velocity of the output shaft of the internal combustion engine, in response to the rotation angle of the measured each time point,
Angular velocity measuring means for measuring as a waveform , the difference between the average rotational angular velocity for a certain period of time before the measurement time point for measuring the rotational angular velocity and the rotational angular velocity measured by the angular velocity measuring means, the angular velocity fluctuation at each measurement time point As the amount Fn, an angular velocity fluctuation amount deriving means to be derived and a normal rotation
In a state where it is clear that there is, the angular velocity fluctuation reference Fs previously obtained as a waveform corresponding to the rotation angle of the output shaft at each measurement time point, and the angular velocity fluctuation amount derivation means derived at each measurement time point. An angular velocity difference deriving means for obtaining an angular velocity fluctuation difference G based on the angular velocity fluctuation amount Fn obtained, and an angular velocity fluctuation difference Da within a predetermined stroke based on the angular velocity fluctuation difference G obtained by the angular velocity difference deriving means.
And a misfire detection device for the internal combustion engine having misfire determination means for judging a misfire state of the internal combustion engine based on the angular velocity variation difference Da. In addition to having a load condition measuring means for measuring a load, the misfire determination means excludes rotation fluctuation due to the load fluctuation, and performs misfire determination based on the angular velocity fluctuation difference Da representing rotation fluctuation. , Can achieve the purpose.

The following effects can be obtained by adopting the above configuration. 1. According to the present invention, the change in the angular speed of the crankshaft of the engine is the response of the change in the load applied to the explosion force and rotation in each cylinder of the engine, and the response of the moment of inertia of the system in which the engine rotates.
What is dependent on the point is that the rotation fluctuation of the portion accompanying the explosive force is detected from the signal of each state. When abnormal,
For example, in the case of a misfire, since the explosive power is reduced, a large amount of rapid rotation fluctuation related to the explosion is detected, and the misfire can be determined with high accuracy. 2. Using the angular speed fluctuation reference Fs, the characteristics of each engine can be input in advance, the difference in the detected amount can be eliminated due to the difference between the individual engines, and the input conditions correspond to the actual operating conditions. Since the estimated condition is estimated, the input operation becomes very simple. 3. Since the angular velocity variation reference Fs is used while being updated, a change in the rotation state can be detected and stored, and it becomes easy to follow a change in the operating state of the engine, a change over time, and the like.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a misfire detection device 10 according to the present invention.
0 is a functional block diagram. As shown in FIG. 1, the misfire detection device 100 includes an angular velocity measuring unit 101 that measures a rotational angular velocity of an output shaft of an internal combustion engine in accordance with a rotational angle at each measurement time point, and a measurement that measures the rotational angular velocity. Mean rotational angular velocity for a certain period before the time and the angular velocity measuring means 1
The angular velocity fluctuation deriving means 102 derives the difference from the rotational angular velocity measured by the above-mentioned method as the angular velocity fluctuation Fn at each measurement time, and measures the output of the internal combustion engine at each measurement time from the generated power. Load condition measuring means 10
3 is provided as a main measurement system. The apparatus further includes a reference angular velocity fluctuation amount generating means 104 for generating an angular velocity fluctuation amount reference Fs which is obtained in advance corresponding to the rotation angle of the output shaft at each time of the measurement. The angular velocity variation deriving means 1 at each time point
A plurality of angular velocity difference deriving means 105 for obtaining an angular velocity variation difference G based on the angular velocity variation Fn derived by the step S04. The angular velocity difference deriving means 105 includes a plurality of such means, and the angular velocity fluctuation amount Fn measured in a preset rotation range.
In order to derive the angular velocity fluctuation difference G based on the relationship between the angular velocity fluctuation reference Fs and the angular velocity fluctuation reference Fs, for example, the difference between the angular velocity fluctuation reference Fs and the angular velocity fluctuation Fn is defined as the angular velocity fluctuation difference G. 1 deriving means 105a, when the angular velocity variation Fn is greater than the angular velocity variation reference Fs, when the angular velocity variation difference G is 0, and when the angular velocity variation Fn is less than the angular velocity variation reference Fs, The second deriving unit 105 sets a difference between the angular velocity variation reference Fs and the angular velocity variation Fn as the angular velocity variation difference G.
b.

Further, based on the angular velocity fluctuation difference G obtained by the plurality of angular velocity difference deriving means 105, an angular velocity fluctuation difference Da within a predetermined stroke is derived, and based on the angular velocity fluctuation difference Da, the internal combustion engine A misfire judging means 106 for judging a misfire state is provided. The misfire determination means 106 is provided with a fluctuation difference amount deriving means 107, which is based on the angular velocity fluctuation differences G obtained by the plurality of angular velocity difference deriving means 105, and determines the angular velocity fluctuation difference amount within a predetermined stroke. Da is derived as an integral value. For example, based on the angular velocity fluctuation difference G obtained by the first deriving means and the second deriving means, respectively, and the distribution functions Ka and Kb depending on the load and corresponding to each deriving means, the angular velocity fluctuation difference Da is calculated. Ask. A configuration is adopted in which the angular velocity variation difference reference value Dt required for determination is output by the abnormal variation amount deriving means 108. Further, the discrimination in the misfire discriminating means 106 is, for example, based on the angular velocity fluctuation difference Da derived based on the angular velocity fluctuation difference G derived by the first deriving means 105a or the second deriving means 105b.
Is larger than the reference value Dt of the angular velocity variation difference of the misfire amount to be determined of the internal combustion engine, it is determined that the misfire is abnormal.

On the other hand, as shown in FIG.
06, the angular velocity variation difference Da measured and derived is sent to the reference angular velocity generating means 104. This means uses the angular velocity variation reference Fs in accordance with the misfire determination standard. And a fluctuation amount reference updating means for updating in accordance with the angular velocity fluctuation difference Da. That is, the reference angular velocity generating means 104 has a function as the fluctuation amount reference updating means 109.

Further, as shown in FIG. 1, the misfire detection device for an internal combustion engine according to the present invention has the angular velocity variation difference Da as a probability function in an operation state that can be regarded as a normal operation state. , And based on the obtained probability distribution of the angular velocity variation difference Da, an angular velocity variation difference reference value Dt for determining an abnormal combustion region.
Is provided. The angular velocity variation difference reference value Dt is a reference value for misfire determination, and a configuration is employed in which the abnormal variation amount derivation means 108 outputs this reference value to the misfire determination means 106.

The configuration of the temporary misfire detection has been described above.
In the present application, an operation state quantity of the internal combustion engine corresponding to the misfire frequency (this state quantity is referred to as a misfire quantity in the present application) can also be output. That is, as shown in the rightmost functional block in FIG. 1, a misfire amount estimation reference value deriving unit 110 and a misfire amount estimation reference value derived by the misfire amount estimation reference value deriving unit 110 (this is Actually, the unit misfire average angular velocity variation difference D
m), and derives a misfire amount based on a predetermined standard.
1 is provided.

Here, the misfire amount estimation reference value deriving means 110
Is a first average value of the angular velocity variation difference Da in the first operating state that can be regarded as a normal operation state, and the average value of the angular velocity variation difference Da in the second operating state that can be considered a forced misfire operation state, As the second average value, a unit misfire average angular velocity variation difference Dm, which is a difference between the first average value and the second average value, is derived. From the relationship between the unit misfire average angular velocity variation difference Dm and the angular velocity variation difference Da measured in the internal combustion engine in the operating state, the misfire amount is obtained by the misfire amount determination means 111. Further, since the angular velocity variation difference determination reference value Dtf for the preset determination reference misfire amount is obtained from the relationship with the unit misfire average angular velocity variation difference Dm, the misfire amount determination means 111 performs measurement. Angular velocity variation difference Da
Exceeds the angular velocity variation difference determination reference value Dtf,
It is configured to generate misfire information. The above is the schematic block configuration of the device.

The configuration and operation of each means will be described below with reference to FIGS.

(A) Angular velocity measuring means 101 In FIG. 2, 5 is a reference position signal generator, 6 is an angular velocity unit signal generator, and 7 is a power meter (this works as a load condition measuring means). Each of these generators 5 and 6 has time signals Pa and P based on the rotation of the camshaft gear 3 and the crankshaft gear 4 of the engine 1 as shown in FIG.
b. That is, the reference position signal generator 5 outputs the signal Pa corresponding to the gear teeth provided at the reference position of the camshaft gear 3. Similarly, it outputs a signal Pb corresponding to the gear teeth provided on the crankshaft gear 4. The generation of the pulse signal is not always performed as in the present embodiment.
For example, by providing a reference signal generator on the crankshaft as shown in FIG. 4 and further providing an ignition signal detection sensor as shown in FIG.
d signal is generated, and from the Pd signal and the Pa signal, Pa
It is also possible to determine the reference position in the same way as the signal. The signal Pb is a signal corresponding to each crank angle, and by measuring the interval time of each pulse, the instantaneous rotational angular velocity near the angle can be obtained. By making this correspond to the signals Pa and Pd, the rotational angular velocity V corresponding to the rotational angle θ of the engine is obtained.

When the engine is running normally,
As shown in FIG. 6, when the rotational angular velocity V accelerates in a part of the explosion-expansion stroke with respect to the crank angle θ and decelerates in the part of the intake and compression strokes, an abnormal combustion (misfire) occurs. As shown in the figure, the waveform is such that even in the expansion stroke in which a misfire has occurred because the explosion does not occur, the speed is further reduced. The engine for the generator is controlled by a governor or the like so as to rotate at a constant speed. However, since the governor responds slowly to a misfire, it takes a long time to start to recover the rotation. For this reason, the rotation of the engine is maintained in such a manner that it temporarily decreases. However, if the difference from the case of normal rotation is taken as it is, even if the rotation is actually normal, the overall speed is not constant, so the difference may be calculated as a rotation fluctuation difference.

(B) Angular velocity fluctuation amount deriving means 102 For this reason, the obtained rotational angular velocity V is further subjected to moving averaging ( Equation 1 ) or a low-pass filter in a certain section.
An average speed Vav is obtained. FIG. 8 shows the average speed in the normal state and the abnormal state. Then, the angular velocity variation Fn is obtained from the average velocity Vav by calculation of (Equation 2).

(Equation 1) Here, n and m are sections for calculating the average speed (for example,
One stroke).

(Equation 2) Figure 9 is the angular speed variation Fn graph obtained when the state of the normal state and abnormal. By doing so, Fn (x) does not depend on a slow load change or a difference in rotation speed, but has a speed depending on the engine condition such as a misfire with a fast change speed. With this angular speed variation Fn, it calculates the actual misfire data.

C. Reference angular velocity variation generation means 104 First, a signal is input in a state where it is clear that the rotation is normal, and a waveform of the angular velocity variation reference Fs is obtained. Here, since the amount of change varies greatly depending on the load, a reference waveform is actually acquired for each predetermined load. However, in this case, it is necessary to check all the loads. Therefore, actually, a certain amount of loads is checked, and a value obtained by linearly interpolating each load for each Fs is used. For example, if a function Fs (x, La) for a certain load La is used, a function Fs (x, Ln) of the load Ln between another load Lb and the function Fs (x, Lb) is calculated as shown in Expression 3. Is done.

(Equation 3) This angular velocity variation reference Fs is also updated during normal detection, which will be described later.

D. Angular velocity difference deriving means 105 In order to confirm how much the velocity actually fluctuates using the angular velocity variation reference Fs determined as described above, the angular velocity variation Fn determined by measurement must be An angular velocity variation difference G is obtained using an analysis function Gn located between the angular velocity variation standard Fs. In the embodiment, the analysis functions Ga and Gb
Use the type.

(Equation 4)

(Equation 5) Here, the analytic function Ga simply obtains the difference from the reference, but the analytic function Gb is a function whose value becomes 0 when the measured value is in an accelerated state from the reference waveform. The analysis function Gb is a function that is normally used when a load is hardly applied. When the rotation depends on the inertia of the engine and the explosive force, and there is almost no difference due to the load change, the load change is slow. The reason for this is to output a value only when the rotation clearly falls below the reference value, since a slight variation causes a greater variation in the integrated value performed thereafter than a variation in the explosive power.

D. Difference amount deriving means 107 The results of the respective analysis functions are collected into one value by load-dependent distribution functions Ka (Ln) and Kb (Ln).

(Equation 6) If the amount of change varies depending on each load,
It is possible to accurately detect the misfire by using those multiple optimal functional or load as a variable (see Figure 10). The obtained S (x, Ln) becomes a value of only the portion where the combustion failure or misfire has occurred as shown in FIG.

[0026] For E misfire discriminating means 106 the angular speed fluctuation amount reference Fs, the result the angular velocity variation difference G calculated from Equation 7, the integral for the stroke velocity
A certain determination value Dt is provided for the variation difference Da, and it is determined whether or not a misfire has occurred in the rotation.

(Equation 7) F. Fluctuation amount reference updating means 109 After finishing this determination, if there is no misfire in the rotation, the reference waveform (angular velocity fluctuation amount reference Fs) is updated according to a certain function U. As a result, it follows that the rotational angular velocity fluctuation of the engine changes due to a change in the state of the engine or a change over time. For example, if the function U is

(Equation 8) In order to determine the next angular velocity variation reference Fs,

(Equation 9) The update is performed gradually according to the values of Ka and Kb during normal operation, and the update amount is reduced during abnormal rotation (see FIG. 12). By performing the above processing, it is possible to determine poor combustion or misfire.

G. Misfire amount determination means 111 In order to obtain a necessary misfire amount, it is necessary to integrate over the respective rotation ranges. So determined Ru angular speed variation difference amount D of the number 10 for up to a defined interval a~b is obtained.

(Equation 10) Here, the D (x, Ln) to obtain, there-determined rotation range a~b or (e.g., one stroke min) is the total amount of by that angular speed variation difference poor combustion or misfires in. Thus, if been obtained it is by that corner speed variation difference amount Dm to misfire of per, the amount Ms of the stall comparable to misfire that occurred to the rotational range a~b is determined to like the number 11.

[Equation 11] As a result, the misfire amount Mn, which is the number of misfires per stroke,
Is

(Equation 12) Becomes If Mn is 1, it means that all cylinders are in a misfire state.

Now, in order to confirm whether or not a state corresponding to misfire or poor combustion has occurred in the rotation, it is necessary to confirm the value of the angular velocity variation difference Da per stroke. With respect to the discrimination value Dt, the apparatus is calibrated while the engine is rotating normally (first operating state),
First, the value of the angular velocity variation difference Da in this state is sampled, the standard deviation thereof is set to σ, and the probability distribution function is set to a normal distribution. Can be reduced to about 2% of the normal rotation. Therefore, if a value exceeding the angular velocity variation difference reference value Dt occurs, it can be considered that misfire or combustion failure has occurred in the process.

G. Misfire amount estimation reference value deriving means 110 Further, the apparatus is calibrated in a state where a misfire occurs due to a forced misfire (second operation state), and D is obtained from the result.
m can be obtained (see FIG. 13). Here, the unit misfire average angular velocity variation difference Dm is a first average value of the angular velocity variation difference Da in a first operation state that can be regarded as a normal operation state, and a second average operation state in a second operation state that can be regarded as a forced misfire operation state. The average value of the angular velocity variation difference Da can be obtained as a second average value, which is a difference between the first average value and the second average value. In this case, the forced misfire occurs in a multi-cylinder engine in a state where one cylinder is misfired. Further, in the above-described determination means, the angular velocity variation difference determination reference value Dtf with respect to the determination reference misfire amount is provided.
Is calculated from the unit misfire average angular velocity variation difference Dm, and misfire information is generated when the measured angular velocity variation difference Da exceeds the angular velocity variation difference determination reference value Dtf. For example, if the determination reference misfire amount misfires once during n strokes, the angular velocity variation difference determination reference value Dtf in the rotation ranges a and b is obtained as shown in Expression 13.

[0030]

(Equation 13) That is, by adopting such a configuration, it is possible to detect a misfire, derive a misfire amount (misfire frequency), and output an alarm signal when the designated misfire amount is reached.

[0031]

According to the present invention, by using an existing sensor and subjecting the sensor output to a predetermined signal processing,
It is possible to provide a misfire detection device that can determine a combustion failure and misfire of an engine and measure the frequency of occurrence.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of a misfire detection device of the present application.

FIG. 2 is a diagram showing a rotation angular velocity and rotation angle detection system;

FIG. 3 is a diagram showing a state of a detection signal.

FIG. 4 is a diagram showing a further rotation angular velocity and rotation angle detection system;

FIG. 5 is a diagram showing a state of a further detection signal;

FIG. 6 is a diagram showing a state of a rotational angular velocity V with respect to a crank angle in a normal operation state.

FIG. 7 is a diagram showing a state of a rotational angular velocity V with respect to a crank angle in an abnormal state;

FIG. 8 is a diagram showing a state of a rotational angular velocity V and a moving average velocity in an abnormal state;

FIG. 9 is a diagram showing a state of an angular velocity fluctuation amount F with respect to a crank angle in an abnormal state;

FIG. 10 is an explanatory diagram of a derivation sequence of an angular velocity variation difference Da.

FIG. 11 is a diagram showing a state of an angular velocity variation difference with respect to a crank angle in an abnormal state;

FIG. 12 is an explanatory diagram of an update sequence of an angular velocity variation reference Fs.

FIG. 13 is a diagram showing an appearance probability distribution of the angular velocity variation difference Da in a normal operation state and an abnormal operation state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine (internal combustion engine) 3 Camshaft gear (rotating shaft) 4 Crankshaft gear (rotating shaft) 5 Reference position signal generator 6 Angular velocity unit signal generator 7 Wattmeter 100 Misfire detection device 101 Angular velocity measuring means 102 Derivation of angular velocity fluctuation amount Means 103 Load status measuring means 104 Reference angular velocity fluctuation amount generating means 105 Angular velocity difference deriving means 105a First deriving means 105b Second deriving means 106 Misfire discriminating means 107 Fluctuation difference amount deriving means 108 Abnormal fluctuation amount deriving means 109 Variation amount reference updating means 110 Misfire amount estimation reference value deriving means 111 Misfire amount determining means

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Tomohiro Ueno 4-1-2, Hirano-cho, Chuo-ku, Osaka City, Osaka Prefecture Inside Osaka Gas Co., Ltd. (72) Inventor Yusuke Fujita 1576-22 (1576-22, Nakahiro, Ako City, Hyogo Prefecture) 56) References JP-A-10-9040 (JP, A) JP-A-10-110649 (JP, A) JP-A-9-166042 (JP, A) JP-A-7-180595 (JP, A) JP-A-7-310586 (JP, A) JP-A-5-71409 (JP, A) JP-A-9-222046 (JP, A) JP-A-7-119536 (JP, A) JP-A 8-28339 (JP) , A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02D 45/00 368 F02P 17/00-17/12

Claims (7)

(57) [Claims] An angular velocity measuring means for measuring a rotational angular velocity of an output shaft of an internal combustion engine as a waveform corresponding to a rotational angle at each time of the measurement is provided. The angular velocity fluctuation deriving means for deriving the difference between the average rotational angular velocity and the rotational angular velocity measured by the angular velocity measuring means as the angular velocity fluctuation Fn at each point in time of measurement, and a state where the rotation is normal. In accordance with the rotation angle of the output shaft at each measurement point, the angular velocity fluctuation reference Fs previously obtained as a waveform and the angular velocity fluctuation amount derived by the angular velocity fluctuation deriving means at each measurement point. Fn and an angular velocity difference deriving means for obtaining an angular velocity variation difference G; and the angular velocity variation difference G obtained by the angular velocity difference deriving means.
, An angular velocity variation difference Da within a predetermined stroke is derived, and based on the angular velocity variation difference Da,
A misfire detection device for a multi-cylinder internal combustion engine for power generation, comprising misfire determination means for determining a misfire state of an internal combustion engine, wherein a load condition measurement means for measuring a load of the internal combustion engine at each measurement time point from generated power. The misfire discrimination means performs misfire discrimination based on the angular velocity fluctuation difference Da representing rotation fluctuation, excluding rotation fluctuation due to the load fluctuation, and according to the misfire determination standard, the angular velocity fluctuation reference Fs
A misfire detection apparatus for a power generating multi-cylinder internal combustion engine, comprising: a variation reference updating means for updating the misfire according to the angular velocity variation difference Da. 2. An angular velocity measuring means for measuring a rotational angular velocity of an output shaft of an internal combustion engine as a waveform corresponding to a rotational angle at each time of the measurement, wherein the rotational angular velocity is measured for a predetermined period before the measurement time at which the rotational angular velocity is measured. The angular velocity fluctuation deriving means for deriving the difference between the average rotational angular velocity and the rotational angular velocity measured by the angular velocity measuring means as the angular velocity fluctuation Fn at each point in time of measurement, and a state where the rotation is normal. In accordance with the rotation angle of the output shaft at each measurement point, the angular velocity fluctuation reference Fs previously obtained as a waveform and the angular velocity fluctuation amount derived by the angular velocity fluctuation deriving means at each measurement point. Fn and an angular velocity difference deriving means for obtaining an angular velocity variation difference G; and the angular velocity variation difference G obtained by the angular velocity difference deriving means.
, An angular velocity variation difference Da within a predetermined stroke is derived, and based on the angular velocity variation difference Da,
A misfire detection device for a multi-cylinder internal combustion engine for power generation, comprising misfire determination means for determining a misfire state of an internal combustion engine, wherein a load condition measurement means for measuring a load of the internal combustion engine at each measurement time point from generated power. And the angular velocity variation reference Fs is a function of the load, and the angular velocity variation reference Fs is calculated as the angular velocity variation difference Da.
A misfire detection device for a multi-cylinder internal combustion engine for power generation, comprising: 3. The angular velocity difference deriving means, based on the angular velocity variation reference Fs and the angular velocity variation Fn derived by the angular velocity variation deriving means at each time of the measurement, calculates an angular velocity variation difference G. The misfire detection device for a multi-cylinder internal combustion engine for power generation according to claim 1 or 2, further comprising a plurality of derivation means for obtaining different procedures. 4. An angular velocity difference deriving means, a first deriving means that sets a difference between the angular velocity variation reference Fs and the angular velocity variation Fn to the angular velocity variation G, and wherein the angular velocity variation Fn is the angular velocity When the variation amount reference Fs is larger than the angular speed variation difference G, the angular speed variation difference G is 0. When the angular speed variation amount Fn is smaller than the angular speed variation amount reference Fs, the angular speed variation reference Fs and the angular speed variation Fn are calculated. And a second deriving unit that sets the angular velocity fluctuation difference G as the angular velocity fluctuation difference G. In order to obtain the angular velocity fluctuation difference Da, the angular velocity fluctuation difference G obtained by the first deriving unit and the second deriving unit, respectively, 3. The misfire detection device for a multi-cylinder internal combustion engine for power generation according to claim 1, wherein the angular velocity variation difference Da is obtained based on distribution functions Ka and Kb corresponding to respective deriving means depending on a load. 5. The multi-cylinder internal combustion engine for power generation according to claim 3, wherein when the angular velocity variation difference Da is larger than a predetermined angular velocity variation difference reference value Dt, the misfire is determined by the misfire determination means. Misfire detection device. 6. An update procedure of said angular velocity variation reference Fs in said variation reference updating means according to a magnitude relationship between said angular velocity variation difference Da and said angular velocity variation reference value Dt. A misfire detection device for a multi-cylinder internal combustion engine for power generation according to the above. 7. An angular velocity measuring means for measuring a rotational angular velocity of an output shaft of an internal combustion engine as a waveform corresponding to a rotational angle at each time of the measurement, and for a predetermined period before the measurement time for measuring the rotational angular velocity. The angular velocity fluctuation deriving means for deriving the difference between the average rotational angular velocity and the rotational angular velocity measured by the angular velocity measuring means as the angular velocity fluctuation Fn at each point in time of measurement, and a state where the rotation is normal. In accordance with the rotation angle of the output shaft at each measurement point, the angular velocity fluctuation reference Fs previously obtained as a waveform and the angular velocity fluctuation amount derived by the angular velocity fluctuation deriving means at each measurement point. Fn and an angular velocity difference deriving means for obtaining an angular velocity variation difference G; and the angular velocity variation difference G obtained by the angular velocity difference deriving means.
, An angular velocity variation difference Da within a predetermined stroke is derived, and based on the angular velocity variation difference Da,
A misfire detection device for an internal combustion engine, comprising: misfire determination means for determining a misfire state of the internal combustion engine, comprising: load condition measurement means for measuring a load on the internal combustion engine at each of the measurement times; However, a misfire detection device for an internal combustion engine that performs misfire determination based on the angular velocity fluctuation difference Da representing rotation fluctuation except rotation fluctuation due to the load fluctuation.