KR100188724B1 - Misfire detecting method and device of engine - Google Patents

Abstract

The present invention relates to a method for detecting a misfire which greatly affects the output of the engine, the life of the cylinder, the concentration of the exhaust gas, and the riding comfort. More particularly, the present invention relates to a method for detecting misfire, The present invention relates to a misfire detection method for an engine which is capable of conveniently detecting an actual misfire of an engine and providing convenience for adjusting the concentration of exhaust gas satisfying North American exhaust gas regulations,

The present invention is characterized in that the time interval for orthogonality to the calculation means is set to t1 tt2, (T) is set as a basic fundamental function, and a value of? N is calculated when n = m, and a value of 0 is calculated when n? M, and the frequency The solution method is And the amplification rate is determined as | a | + | b |, the fact that the engine is misfired can be easily and quickly detected by a simple calculation. Therefore, the limited memory area of the ECU can be efficiently used without additional hardware, And the cylinder in which the misfire has occurred are stored in the memory means, thereby providing quickness and convenience in maintenance and reliability in detection of misfire.

Description

Method and apparatus for detecting misfire of engine

FIG. 1 is a block diagram of a misfire detecting apparatus for an engine according to the present invention. FIG.

FIG. 2 is a flow chart of one embodiment for performing the misfire detection of the engine in the present invention shown in FIG. 1; FIG.

FIG. 3 is a waveform diagram of a simple function for detecting misfire of an engine in an embodiment of the present invention shown in FIG. 2; FIG.

FIG. 4 is a waveform diagram of a triangular matrix function for approximating the simple function shown in FIG.

FIG. 5 is a waveform chart of the normal combustion of the engine. FIG.

FIG. 6 is a waveform diagram that is detected when a misfire occurs in the engine. FIG.

[Industrial Applications]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting a misfire which causes a great influence on the output of an engine, the life of a cylinder, the concentration of exhaust gas, (CARB OBD II) and the adjustment of the engine dissonance by detecting the actual misfire of the engine by converting the trigonometric function of the basic function of the engine to the walsh function. The present invention also relates to a misfire detection method and apparatus for an engine that provides reliability for detection of convenience and misfire.

[0003]

Generally, misfiring of an engine is caused by incomplete compression or a concentration of a lean mixer or a failure of an electric ignition device to cause non-sparking, non-ignition ignition failure and propagation failure of a once formed flame, The exhaust of exhaust gas containing a large amount of harmful substances exceeds the range of North American exhaust regulations due to the decrease in output due to the decrease of the torque of the engine and the abrasion of the inner wall of the cylinder and the unstable ride .

In order to detect the misfire of the engine as described above, a conventional automobile detects a discrepancy due to the vibration intensity of the engine and compares the amount of change of the angular velocity (acceleration) for a predetermined time, (DFS) method using the Kono matrix function. Since the misalignment measurement method of the engine through the detection of the angular velocity for a predetermined time is a function of time, overlapping of data occurs in the region of low load speed There is a problem that reliability is deteriorated in detection of data on accurate misfire.

In addition, although the misfire measurement method of the frequency prediction using the trigonometrical function can measure the misfire in the entire operation region, the calculated value for the misfire detection is relatively large, and the load is increased in the application to the currently used ECU There has been a problem in that a delay occurs in the occurrence of an error of data and in the processing of other control functions, and normal ECU functions can not be executed.

[Purpose for solving the problem]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and its object is to provide a simple function for transforming a triangular matrix function, which is a basic function of a frequency prediction method, into a simple function, It is possible to detect the misfire of a single cylinder satisfying the North American exhaust regulations and to detect the misfire of a plurality of cylinders at the same time and to recognize the number of the cylinder in which the misfire occurs, It is possible to carry out the concentration adjustment of the exhaust gas satisfying the North American exhaust regulations conveniently and quickly.

[MEANS FOR SOLVING THE PROBLEM]

According to another aspect of the present invention, there is provided a misfire detection method for an engine, comprising: a first step of determining whether a misfire detection condition is satisfied through data detected according to a rotation of a crankshaft; A second step of summing the detection data of the TDC interval by a predetermined number of times set by the addition means when the misfire detection condition is satisfied; a third step of correcting the ripple, RPM and load of the summed detection data in the second step, And a third step of, when flood of the data stored in the third step occurs, detecting the data to be flooded through the calculation means and the set virtual data, and comparing the detected data with the reference data value set for the misfire detection, A fourth step of determining whether or not the data to be detected exceeds the reference data, A fifth step of counting the number of times exceeded by the counter means and determining whether or not the detected number of times is a predetermined number of times detected; And reading the cylinder in which the misfire has occurred, storing the cylinder in the memory means, and proceeding to program for misfilm correction.

The present invention also provides an engine misfire detecting apparatus comprising crankshaft position detecting means for detecting an explosion state of each cylinder through a rotational position of a crankshaft rotated in accordance with an explosion stroke and outputting a predetermined signal corresponding thereto, Control means for controlling the overall operation of detection of a cylinder misfire and detection of a misfire occurring in each cylinder based on the detected and applied signal; An addition means for correcting the RPM, the ripple and the load of the calculated result after adding the state data of each cylinder detected in accordance with the signal of the control means, The data sum of each cylinder that is calculated and supplied through the cylinder is sequentially stored temporarily A comparison means for comparing the calculated result with the reference data set for recognition as a misfire, and a comparison means for comparing the calculated result with the reference data set for recognition as a misfire, A counter means for counting data to be detected and applied and detecting an exceeding number of reference values, and reference data for detecting a misfire of the cylinder explosion stroke are set, and the cylinder of the cylinder for which the misfire is detected, And second memory means for storing the data as backup data in the second memory means.

[Example]

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

1, the misfire detection apparatus for an engine according to the present invention includes a crankshaft position detection unit 10, a control unit 20, a first memory unit 30, an adder 40, a buffer 50, An arithmetic unit 60, a comparator 70, a counter 80 and a second memory unit 90.

The crankshaft position detection section 10 detects the explosion state of each cylinder through the rotation position of the crankshaft rotated in accordance with the explosion stroke executed in the order of 1 → 3 → 4 → 2 based on the four-cylinder engine And outputs a predetermined signal corresponding thereto.

For example, it is possible to output 58 sawtooth waves including one tooth for detection of a misfire per revolution of the crankshaft, and to include two sawtooth waves for detection of misfires per one camshaft of the engine Outputs 116 sawtooth waves.

The control unit 20 controls whether or not the cylinder misfire detection progresses from the signal detected and applied in accordance with the rotation of the crankshaft and the overall operation for detecting the misfire occurring in each cylinder.

The first memory unit 30 stores operation program data for operation of the control unit 20 and reference program data for detecting whether a misfire has occurred.

When the number of sawtooth waves calculated by adding the number of saw teeth of each cylinder applied through the control unit 20 becomes a predetermined number (for example, 29), the adder 40 adds the RPM of the calculated result to the ripple And the load is reset and reset according to the signal of the control unit 20 at the same time as outputting, and the addition operation is made large.

The buffer 50 sequentially stores the saw tooth counts of the respective cylinders calculated and applied through the adder 40 in order.

The arithmetic unit 60 performs a real number operation and an imaginary number arithmetic operation on the output value stored in the buffer 50 according to a signal applied from the control unit 20 and outputs the calculated operation result to the comparator 70 side.

The comparator 70 compares the calculation result applied through the arithmetic unit 60 with the reference data set to be recognized as a misfire applied from the control unit 20. [

The counter 80 counts the number of exceeded reference values detected and applied from the comparator 70 and outputs a predetermined signal corresponding thereto.

In the second memory 90, reference data for detecting the misfire of the cylinder explosion stroke is set, and the cylinder of the cylinder where the misfire is detected and its state are stored as back up data at a predetermined address.

The operation of detecting the misfire of the present invention having the above-described functions will be described as follows.

First, the basic function selection for approaching the misfire detection of the engine is required to satisfy the orthogonality between the basic functions in the finite section. to be.

At this time, the time interval t1 tt2 for mutual orthogonality, ψi (t) is a substantial fundamental function, the value of λn is calculated when n = m, and the value of 0 is calculated when n ≠ m.

The simplest function satisfying the orthogonality between the basic functions in the finite interval is a basic function consisting of the simple functions as shown in FIG. 3 of the accompanying drawings. The proof function is as follows.

to be.

therefore, And (Ψ ₁ , ψ ₂ ) of the simple fundamental function satisfy the orthogonality with each other and satisfy the orthogonality with respect to the remaining ψi.

When the solution of the frequency analysis method using such a simple function is detected to be.

In this case, as shown in FIG. 3, the simple function has a value of 1 or -1, so that all the multiplications of the solution detected in the above are simplified in the form of addition and subtraction.

The final solution is broken down into the following sections.

ego,

to be.

At this time, the amplification factor is | a | + | b |, and the phase is a step function of each cylinder interval, so that it is not necessary to calculate the phase.

In addition, a function satisfying the orthogonality between basic functions in a finite interval is a triangular matrix function as can be seen in FIG. 4 of the accompanying drawings.

Lt;

ego

The fundamental signals (ψ1, ψ2) of the triangular matrix function satisfy the orthogonality and also satisfy the orthogonality with respect to the remaining ψi.

By defining the solution of the frequency analysis method through the triangular matrix function defined as above to be.

here, And k is the frequency.

If frequency analysis is performed for frequency 1 in Figure 4 attached hereto through the solution defined above, to be.

4, ego, , The amplification factor is And the phase is .

As a result of the above-described proof, the simple function as shown in FIG. 3 of the accompanying drawings and the trigonometric function as shown in FIG. 4 of the attached drawings satisfy the approach to the basic function for detecting the misfire of the engine, In order to detect a misfire through frequency analysis according to a period, the data area of the triangular matrix function is wide and the use area of the memory means for data processing increases, and the processing speed is delayed by processing a wide range of data. The data area is narrow and the data processing speed and the simple function that does not occupy much memory area are realized.

This will be described with reference to the accompanying drawings, FIG. 2, which is a flow chart.

For example, when the engine of a vehicle in a stationary state using a general four-cylinder engine is turned on, the crankshaft position detection unit 10 detects a signal about the rotation of the crankshaft that drives the cylinder and the camshaft To the control unit 20 side (step 101).

At this time, the crankshaft position detection unit 10 outputs 58 sawtooth wave signals including one sawtooth wave signal for detection of misfire per one rotation of the crankshaft, so that two sawtooth wave signals To output 116 sawtooth signals.

When the misfire detecting condition of the engine is set in accordance with the sawtooth wave signal for detecting the misfire which is applied in step 101 (step 102), the control unit 20 judges whether or not each cylinder (For example, 29), the summed result is output to the buffer 50 side, and the summed result is outputted to the buffer 50 side And the summing operation of the adder 40 is reset (step 103).

Thereafter, the buffer 50 having a predetermined storage capacity corrects the ripple of the sawtooth wave signal for each cylinder applied from the adder 40, the RPM and the transmission load, and then sequentially stores the ripple (step 106) When the overflow of data to be stored exceeds the capacity of the buffer 50 and the detected data stored in the most significant bit of the buffer 50 is applied to the computer 60, (Step 106) for the real and imaginary sides of the data detected through the solution of the simple function defined as described above.

At this time, the control unit 20 clears the detection data stored in the most significant bit of the buffer 50, sequentially shifts the data for each cylinder stored in each bit, moves the stored bit to an upper bit, Lt; RTI ID = 0.0 > adder 40 < / RTI >

When the operation of step 106 is completed, the control unit 20 compares the calculated data of the misfire detection and the reference data set in the first memory unit 30 through the comparator 70, It is judged whether or not it exceeds the range of the set reference data (step 107).

If the data detected in step 107 does not exceed the range of the reference data set for the misfire detection, it is determined that the four peak waveforms are formed at the same level as normal combustion (step 130). When the detected data exceeds the range of the reference data set for the misfire detection, an excess count detected through the counter 80 is counted (step 108), and a predetermined number of counts (for example, 3 Times) (step 109).

If the data for the misfire detection detected by the counting in the step 108 is a preset number of times (for example, three times), as can be seen from FIG. 6, the peak waveform for the engine combustion is unstably formed After determining that the cylinder is misfiring (step 110), the misfiring cylinder is detected and stored in a predetermined address of the second memory unit 90, and the misfire correction operation set in the first memory unit 30 is sequentially performed So that the combustion of the engine is normally maintained (step 111, step 112).

For example, if the sawtooth wave signal applied from the crankshaft position detecting unit 10 is read from the explosion stroke of the No. 1 cylinder, the first one cycle of the frequency prediction method to be read is 1-3 When the cylinders in the order of -4-2 are read and moved at intervals of 1 TDC (top dead center) in accordance with the progress of the misfire detection operation, the explosion stroke of one cycle detected next is a cycle of 3-4-2-1 .

At this time, when a misfire occurs in a single cylinder, when a large value is continuously detected to be less than a predetermined number (approximately 3 times) in accordance with the movement of the TDC interval, it is judged as noise, and a predetermined number of times ), The final large value is the cylinder that caused the misfire.

If it is detected in step 109 that the number of data detected by counting is more than a predetermined number (for example, three times), it is determined whether or not the number of times of counting is detected four times, five times, or six times Step 120).

If it is determined that the number of counts detected in step 120 is not detected four times, five times, or six times, for example, it is determined that combustion of the engine is proceeding normally. If a large value continuously detected in accordance with the counting is not less than a predetermined number For example, if it is detected four times, five times, and six times, it is determined that a plurality of cylinders are misfire. If the detected number of times is four, it is determined that a misfire has occurred in the cylinder with the last large value and the cylinder immediately before, If the detected number of times is 5, it is judged that a misfire has occurred in the cylinder with the last large value and the second cylinder as shown in Table 2. If the detected number of times is 6, the cylinder with the last large value and the third After determining that a misfire has occurred in the cylinder (step 121)

Table 1. (1,3), (3,4), (4,1), ...

Table 2. (1,4), (3,2), (4,1), ...

Table 3. (1,2), (3,1), ...

Each cylinder in which a misfire has occurred is detected and the second memory unit 90 stores the address at a predetermined address and a predetermined correcting operation for normal combustion is performed (step 112).

[Effects of the Invention]

As described above, according to the present invention, it is possible to easily and quickly detect whether or not the engine is misfired by a simple function through a simple function. Therefore, it is possible to efficiently use the limited memory area of the ECU without additional hardware, The cylinder misfire and the misfire for a plurality of cylinders are simultaneously detected, and at the same time, the cylinder in which the misfire is generated is stored in the memory means, thereby providing prompt maintenance, convenience, and reliability in detection of misfire.

Claims (13)

A method for detecting a misfire in an engine, the method comprising: a first step of determining whether a misfire detection condition is satisfied through data detected according to a rotation of a crankshaft; A third step of accumulating the ripple and the RPM and the load of the summed detection data in the buffer and storing the corrected data in a buffer; When data overflow occurs, the detection data to be overflowed through the calculation means and the calculated virtual data are compared with the reference data value set for the misfire detection after calculating the calculated data, and it is determined whether or not the detected data exceeds the reference data If the data detected in the fourth step exceeds the set reference data, A fifth step of judging whether or not a predetermined number of times is detected by counting the number of times exceeding a predetermined number of times, And a sixth step of storing the program in the memory means and proceeding with a program for misalignment correction. 2. The misfire detection method for an engine according to claim 1, wherein, in the second step, when the sum of detected data of the summed TDC intervals reaches a predetermined number, the adding operation of the adding means is cleared so that the new detected data advances the adding operation. 2. The method of claim 1, wherein if the operation is performed by overflowing the data stored in the fourth step, the data stored in the most significant bit of the operation is cleared, the data stored through the shift is stored and newly computed in the least significant bit And the data is stored in the memory. 2. The method according to claim 1, wherein orthogonality between basic functions in a finite section must be satisfied in the basic function set in the calculation means for detecting the misfire of the engine. 5. The method according to any one of claims 1 to 4, wherein the calculation means is set to a time interval t1 tt2 for orthogonality, (T) is set as a basic basic function, a value of? N is calculated when n = m, and a value of 0 is calculated when n? M. Way. The method according to any one of claims 1 to 5, wherein the solution of the frequency analysis method through the simple function set in the calculation means is And the amplification factor is set to | a | + | b |. 7. The misfire detection method for an engine according to any one of claims 1 to 6, wherein said calculation means sets not to perform calculation of phase because each cylinder interval is a step function. 2. The engine misfire detecting method according to claim 1, wherein the number of counting times set in the fifth step is set three times in the case of detection of a misfire of a single cylinder, and four or more times in the case of misfiring detection of a plurality of cylinders . The misfire detection method for an engine according to claim 1, wherein if the count value of the data detected in the fifth step is not detected as exceeding the set reference data, it is determined that the engine is normally burned. 2. The method according to claim 1, wherein when the number of data counted and detected in the fifth step is detected three times, it is determined that the single cylinder is a misfire, and if the number of data counted and detected is four or more, Detecting the cylinder in which the misfire has occurred, storing the detected cylinder in the memory means, and executing the misfire compensation operation. 11. The method according to any one of claims 9 to 10, wherein the misfire determination data detected in the fifth step is detected through continuous counting. An engine misfire detecting apparatus comprising: crankshaft position detecting means for detecting an explosion state of each cylinder through a rotational position of a crankshaft rotating in accordance with an explosion stroke and outputting a predetermined signal corresponding thereto; A control means for controlling the overall operation of detecting the misfire of the cylinder from the signal and the detection of the misfire occurring in each cylinder, and a control means for controlling the overall operation program data of the engine ignition and the reference program data for detecting the occurrence of misfire, An addition means for adding the state data of each cylinder detected in accordance with the signal of the control means and correcting the RPM, the ripple and the load of the calculated result after the state data of each cylinder is added in accordance with the signal of the control means, A buffer for temporarily storing a data sum of each of the cylinders sequentially, A comparison means for comparing the calculated result with the reference data set for recognition as a misfire, and a comparison means for comparing the calculated data And reference data for detecting the misfire of the cylinder explosion stroke are set, and the cylinder of the cylinder for which the misfire is detected and its state are stored as backup data at a predetermined address address And a second memory means for storing the actual state of the engine. The misfire detection device for an engine according to claim 12, wherein the crankshaft position detection means outputs 58 saw tooth wave signals including one data for detection of misfire per rotation of the crankshaft.