JP4313733B2 - Engine cylinder determination device - Google Patents

Description

  The present invention relates to a cylinder determination device for determining which cylinder is in a specific stroke in a multi-cylinder engine such as a three-cylinder engine.

  One cycle of the operation of the engine is composed of a plurality of strokes, for example, 2 or 4. For this reason, in a multi-cylinder engine having two or more cylinders, any cylinder is used for controlling ignition timing, fuel injection timing, and the like. Needs to be identified whether it is in a particular stroke, eg a compression stroke. For this reason, cylinder determination is required.

By the way, as such a cylinder determination device, as a first conventional example, as described in the following Patent Document 1 or the like, a protrusion for determining a crank angle of each cylinder is provided on a circular rotating member mounted on a camshaft. A different number of protrusions are provided for each cylinder, the protrusions are detected by a crankshaft detector (detector), and a specific bit state is determined from the ratio of time intervals of pulse signals obtained from the crankshaft detector. However, there is a type in which a predetermined crank angle of a predetermined cylinder is determined when the bit state arrangement becomes a predetermined arrangement pattern.

As a second conventional example, a reference signal (pulse) and a rotation angle signal (pulse) corresponding to each cylinder are obtained by an optical crank angle sensor as described in Patent Document 2 below, There is one that determines a predetermined crank angle of a predetermined cylinder from the number of rotation angle signal generations during a pulse width period of a reference signal.
Japanese Patent Laid-Open No. 11-31147 (pages 1 to 9, FIGS. 1 to 17) JP-A-6-185399 (pages 1-6, FIGS. 1-7)

  However, in the first conventional example, in an engine having four or more cylinders, the number of protrusions for determining the crank angle is increased and the angular interval between the protrusions is reduced. For this reason, there is a problem that it is difficult to detect the protrusion in the magnetic or Hall element type crank angle sensor that detects a change in the magnetic field generated when the protrusion passes through the crank angle sensor (detector). . Further, it is necessary to lengthen the arrangement state of the pulse intervals to be checked for crank angle determination, and there is a problem that the time until cylinder determination becomes long.

  Further, in the second conventional example, since an optical crank angle sensor is used, detection at every crank angle of 1 ° is possible. Therefore, even if the number of cylinders of the engine increases, it is possible to detect a predetermined crank angle of a predetermined cylinder. Also, the time until cylinder determination does not increase. However, there is a problem that the optical crank angle sensor is more expensive than a crank angle sensor such as a magnetic type, a Hall element type, or a magnetoresistive element type.

  Furthermore, most of the conventional cylinder determination devices cannot actually perform cylinder determination for odd-numbered cylinder engines such as a three-cylinder engine (the reference from the crank angle sensor while the crankshaft rotates twice). (It is impossible to get the signal three times (odd times)).

  Further, in a conventional cylinder determination device, in an engine having a valve operating mechanism in which the valve timing of the intake and exhaust valves is variable, when the valve timing of the intake and exhaust valves is changed, the signal from the cam angle sensor is changed to the crank angle. Since it will shift | deviate with respect to the reference signal obtained from a sensor, there exists a possibility of producing a misjudgment.

  The present invention has been made to solve the conventional problems as described above. The object of the present invention is to make the valve timing of the intake and exhaust valves variable even in an odd-numbered cylinder engine such as a three-cylinder engine. It is another object of the present invention to provide a cylinder determination device for an engine that can perform cylinder determination promptly without error even in an engine equipped with a valve mechanism, and is advantageous in terms of cost.

  In order to achieve the above object, a cylinder discriminating apparatus for an engine according to the present invention includes a crank angle sensor, a cam angle sensor, and control means for performing cylinder determination based on signals obtained from both the sensors.

  The crank angle sensor includes a crankshaft circular rotating member that is rotated integrally with the crankshaft, and a crankshaft detector disposed in proximity to the outer periphery of the crankshaft circular rotating member. At the outer periphery of the circular rotating member, there are at least two of the above-mentioned objects to be detected, each of which has a plurality of detected parts made up of teeth, protrusions, concave parts, convex parts, holes, etc. The non-uniformly spaced portions in which the detectors are arranged at larger angular intervals than the equally spaced portions are alternately provided by the same number as the number of cylinders of the engine, and the crankshaft detector detects the detected portion. In addition, the cam angle sensor is provided on the outer periphery of the cam shaft circular rotating member and the cam shaft circular rotating member that are rotated together with the cam shaft. Detected part group comprising one or more detected parts comprising teeth, protrusions, concave parts, convex parts, holes, etc. on the outer peripheral part of the cam shaft circular rotating member arranged in contact with each other Are provided at equal angular intervals by the same number as the number of cylinders of the engine, each of the detected portion groups is formed by a different number of the detected portions, and the cam shaft detector is It is characterized in that a pulse as a signal is generated each time the detection unit is detected.

  In this case, each detected group of the camshaft circular rotating member is preferably arranged at an angular interval obtained by dividing 360 ° by the number of cylinders of the engine, and any detected group belongs to at least one of them. The timing at which one detected portion is detected by the camshaft detector is predetermined before and after the timing at which the detected portions of the unevenly spaced portion in the crankshaft circular rotating member are detected by the crankshaft detector. Arranged to be within an angle.

  Preferably, the control means detects the unequal interval portion based on a signal obtained from the crank angle sensor, counts the number of detections, detects the first time, and then detects the third time. Cylinder determination is performed based on the number of signals from the cam angle sensor that arrived within the period.

  In this case, the control unit preferably counts the number of detections of the unequal interval portion, and the signal from the cam angle sensor arrives within a predetermined time or angle before and after the unequal interval portion is detected. If not, the count is counted as the first time, and if the third time is detected, the count is further stopped and a new cylinder determination is performed.

  Further, the control means preferably measures the time interval of the signal obtained from the crank angle sensor, and sequentially stores it as a previous time interval t3, a previous time interval t2, and a latest time interval t1. , T2 / t1> constant value A1 (formula 1) and t2 / t3> constant value A2 (formula 2) are calculated using the stored time intervals t3, t2, and t1. When both 1) and (Expression 2) are satisfied, it is determined as the unequal interval portion, and when at least one of both expressions (Expression 1) and (Expression 2) is not satisfied, it is determined as the equally spaced portion. By doing so, the identification detection of the unequal interval portion and the equal interval portion is performed.

  As the crank angle sensor, a magnetic type, a Hall element type, or a magnetoresistive element type can be used.

  Preferably, the control means sequentially measures the time required for the crankshaft to rotate by a predetermined angle based on a signal obtained from the crank angle sensor, and based on the required time, the presence or absence of misfire in each cylinder. Etc. are determined.

  As the engine, an odd-numbered cylinder engine can be applied, and an engine having a valve operating mechanism in which the valve timing of the intake valve and / or the exhaust valve is variable can be applied.

  The cylinder determination device for an engine according to the present invention can perform cylinder determination promptly without error even in an odd-numbered cylinder engine such as a three-cylinder engine or an engine equipped with a valve mechanism that varies the valve timing of the intake and exhaust valves. Can be done.

  Further, since the crank angle sensor can be an inexpensive magnetic type, Hall element type, magnetoresistive element type or the like instead of an expensive optical type, the apparatus cost can be kept low.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an embodiment of a cylinder determination device according to the present invention together with a vehicle-mounted three-cylinder engine to which the cylinder determination device is applied.

  In FIG. 1, an engine 1 includes a cylinder 1a provided with three cylinders (# 1, # 2, # 3) and pistons slidably fitted into the cylinders (# 1, # 2, # 3). 1b, a combustion plug 1c above the piston 1b is provided with a spark plug 18, an intake passage 4 provided with an electronically controlled fuel injection valve 6, and an exhaust passage provided with an air-fuel ratio sensor 11. 19 is connected. An intake valve 7 and an exhaust valve 8 that are driven to open and close by a valve mechanism (not shown) are disposed at the downstream end (intake port) of the intake passage 4 and the upstream end (exhaust port) of the exhaust passage 19. . A water temperature sensor 12 is provided in the cylinder 1a.

  A throttle body 2 having an air cleaner 5 and a throttle valve for adjusting the amount of intake air is disposed at the start end of the intake passage 4. The throttle body 2 is provided with an ISC valve 21 and a throttle sensor 17 and a pressure sensor 16.

  The fuel in the fuel tank 30 is supplied to the fuel injection valve 6 by the fuel pump 31, but is adjusted by the regulator 32 and reaches the fuel injection valve 6 through the fuel pipe 33, and the fuel injection valve 6 passes to the intake port. It is injected towards.

  In the engine 1 having such a configuration, as shown in FIG. 4, the vertical movement of the piston 1 b is converted into a rotational movement by the crankshaft 60, and the rotation is converted to the crank pulley 69, the timing belt 68, the intake cam pulley 64, and the exhaust gas. This is transmitted to the valve operating mechanism 40 including the intake camshaft 62 and the exhaust camshaft 65 through a transmission mechanism 70 constituted by a cam pulley 67, and thereby the intake camshaft 62 is rotated at half the rotational speed of the crankshaft 60. The exhaust cam shaft 65 is rotationally driven, the intake valve 63 is opened and closed by the intake cam 63 provided on the intake cam shaft 62, and the exhaust valve 66 is provided by the exhaust cam 66 provided on the exhaust cam shaft 65. 8 is driven to open and close.

  The engine 1 includes a crank angle sensor 13, a cam angle sensor 14, and a control unit 100 that are used for cylinder determination, as will be described in detail later.

  Signals from the throttle sensor 17, the pressure sensor 16, the air-fuel ratio sensor 11, the water temperature sensor 12, the crank angle sensor 13, the cam angle sensor 14, and the like are input to the control unit 100, and the control unit 100 receives these signals. Based on this, fuel injection control by the fuel injection valve 6, opening control of the ISC valve 21, control of ignition timing by the ignition coil 9 and ignition plug 18, control of the fuel pump 31, and the like are performed. In FIG. 1, reference numeral 22 denotes a battery, reference numeral 23 denotes a main relay for the control unit 100, and reference numeral 24 denotes a fuel pump relay.

  As shown in FIG. 2, the control unit 100 has a well-known configuration, and includes an input circuit 191, an A / D conversion unit 192, a CPU 193, a ROM 194, a RAM 195, and The microcomputer includes an output circuit 196. In the case of an analog signal, the input circuit 191 receives signals from, for example, the water temperature sensor 12 and the throttle sensor 17, removes noise components from the signals, and outputs the signals to the A / D converter 192. Is for.

  The CPU 193 functions to execute the respective controls and diagnoses by taking in the A / D conversion results and executing a fuel injection control program stored in a medium such as the ROM 194 and other predetermined control programs for control. It has. The calculation result and the A / D conversion result are temporarily stored in the RAM 195, and the calculation result is output as a control signal 197 through the output circuit 196 and used for fuel injection control, ignition timing control, and the like. .

  On the other hand, signals obtained from the crank angle sensor 13 and the cam angle sensor 14 are identified by the input circuit 191 as to the presence or absence of signals, and are sent to the CPU 193 through the signal lines 198 and 199 as High / Low signals. In the CPU 193, when the voltage level of the signal line 198 changes from Low to High, an interrupt process is performed at a timing indicated by γ in FIG.

  The crank angle sensor 13 is, for example, a magnetic type, and as shown in FIG. 4, the crank angle sensor 13 is mounted on the crankshaft 60 and rotated integrally therewith. And a crankshaft detector 13b disposed in close proximity to the outer periphery of the crankshaft circular rotating member 13a.

  On the outer periphery of the crankshaft circular rotating member 13a, as schematically shown in FIG. 5, a large number of detected portions 15 made of rectangular teeth or protrusions (shown by a single line) are equiangularly spaced ( Here, the equally-spaced portions 25 arranged over a predetermined angle range at 10 ° CA) and at least two of the detected portions 15 are arranged at an angular interval larger than the equally-spaced portions 25 (here, 30 ° CA). The non-uniformly spaced portions (tooth-missing portions) 26 are alternately provided at intervals of 120 ° CA by the same number as the number of cylinders (here, 3) of the engine 1.

  The crankshaft detector 13b is generated each time the detected portion 15 passes directly opposite the crankshaft circular rotating member 13a rotating with the crankshaft 60, as shown in FIG. A change α in the magnetic field is captured (detected portion 15 is detected), and a pulse β as a signal is generated by an internal processing circuit, which is supplied to the control unit 100.

  On the other hand, the cam angle sensor 14 is, for example, a magnetic type, and as shown in FIG. 4, the cam angle sensor 14 is mounted on the cam shaft 62 and rotated integrally therewith. 6 includes a member 14a and a camshaft detector 14b disposed in close proximity to the outer periphery of the camshaft circular rotating member 14a. The outer periphery of the camshaft circular rotating member 14a is schematically illustrated in FIG. As shown in FIG. 4, the detected portion group 27 (27A, 27B, 27C) having one or more detected portions 15 made of rectangular teeth or protrusions (indicated by a single line) has the number of cylinders of the engine ( Here, they are provided at intervals of 120 ° (240 ° CA) by the same number as 3). Each of the detected unit groups 27A, 27B, and 27C is formed of a different number, that is, three, two, and one detected unit 15.

  Further, in each of the detected groups 27A, 27B, and 27C of the cam shaft circular rotating member 14a, at least one detected portion 15 belonging to each detected group is detected by the cam shaft detector 14b. The time is within a predetermined angle (for example, 15 ° CA) before and after the time when the detected portion 15 of the unequal interval portion 26 in the crankshaft circular rotating member 13a is detected by the crankshaft detector 13b. Is arranged.

  When the camshaft circular rotating member 14a is rotating together with the camshaft 62, the camshaft detector 14b is similar to the crankshaft detector 13b as shown in FIG. The change α of the magnetic field generated every time the line 15 passes directly (detecting the detected part 15), the internal processing circuit generates a pulse β as a signal, and supplies this to the control unit 100.

  FIG. 7 shows the relationship among the strokes of the cylinders # 1, # 2, and # 3 of the engine 1, the crank signal obtained from the crank angle sensor 13, and the cam signal obtained from the cam angle sensor 14 in the present embodiment. is there.

  As can be clearly understood with reference to FIG. 7, a signal group 26 a with a 30 ° CA interval corresponding to the unequal interval portion 26 and an equal interval portion are provided from the crank angle sensor 13 to the control unit 100 every 120 ° CA. And a signal group 25a with a 10 ° CA interval corresponding to 25 is supplied. In addition, from the cam angle sensor 14 to the control unit 100, a signal group 27a composed of three signals and two signals in order corresponding to the detected groups 27A, 27B, and 27C every 240 ° CA. A signal group 27b and a signal group 27c consisting of one signal are supplied.

  The position (arrival time) relationship between the crank signal from the crank angle sensor 13 and the cam signal from the cam angle sensor 14 is related to the detected portions 27A, 27B, and 27C of the circular rotating member 14a for the cam shaft. As shown in FIG. 7, the two signal groups 27 a, 27 b, and 27 c appear in the vicinity of the signal group 26 a having a 30 ° CA interval corresponding to the unequal interval portion 26.

FIG. 8 is a functional block diagram showing the cylinder determination process contents of the control unit 100.
The crank signal from the crank angle sensor 13 is input to the input processing unit 210 to remove noise and the like. Noise from the cam signal from the cam angle sensor 14 is also removed by the input processing means 220. The inputted crank signal is counted by the crank signal counting means 230 until the cam signal is inputted, and the crank signal count signal is continuously output, and the unequal interval portion detecting means 240 is arranged at unequal intervals. The detection signal is converted into a cylinder determination window signal by the window detection means 250 together with the value of the crank signal count signal. The cam signal and the cylinder determination window signal are input to the cam signal counting means 260. When the cylinder determination window signal is input, the number of the cam angle signal is input until the next cylinder determination window signal is input. And the cam signal count signal is continuously output.

  In the case of the three-cylinder engine 1, the cam signal count signal is continuously patterned and generated and output as 321321,. The patterned count signal generated in this way is output to the cylinder determining means 280 to perform cylinder determination. Cylinder determination is performed by taking out pattern data determined in advance by the cylinder determination reference storage means 270, comparing with the count signal number, and confirming whether or not they match.

Next, the non-uniform interval detection method of the non-uniform interval detection unit 240 will be described with reference to FIG.
As shown in FIG. 9, the signal group 26a corresponding to the unequal interval portion 26 is located between the crank signal BTDC 105 ° CA signal and the BTDC 75 ° CA signal. The unequal interval portion 26 is detected by comparing the time t2 between the crank signal BTDC 105 ° CA signal and the BTDC 75 ° CA signal and the time t3 and t1 between the preceding and succeeding crank signals.

Specifically, the control unit 100 measures the time intervals of the signals obtained from the crank angle sensor 13 and stores them sequentially as t3, t2, t1, and the stored time intervals t3, t2, The following (Equation 1) and (Equation 2) are calculated using t1, and when both (Equation 1) and (Equation 2) are satisfied, it is determined as the unequal interval portion, and (Equation 1) and When at least one of (Equation 2) is not established, it is determined that it is the equally-spaced portion, and the unequal-spaced portion 26 and the equally-spaced portion 25 are identified and detected.
t2 / t1> A1 (Equation 1)
t2 / t3> A2 (Equation 2)
T1: Latest time interval
t2: Last time interval
t3: Time interval before the last time
A1: Constant value
A2: Set to a constant value.

  A1 and A2 have a value of about 2. In other words, when converted by the angle ratio, t1 is 10 °, t2 is 30 °, t3 is 10 °, t2 / t1 = t2 / t3 = 3, and if the values of A1 and A2 are 2, the unequal interval portion 26 detections are possible.

Next, a method for forming a cylinder determination window signal by the window detection means 250 will be described with reference to FIG.

The window detection means 250 allows the value of the crank signal count signal at the time when the unequal interval position detection signal is output by the unequal interval position detection means 240 to be within the range Y indicated by the broken line in FIG. For example, a cylinder determination window signal is output.

  FIG. 11 shows the relationship among the strokes of the cylinders # 1, # 2, and # 3, the crank signal, the cam signal, the cylinder determination window, and the cam signal count number between the unequal intervals in the present embodiment.

  The cam signal count signal input between the cylinder determination window signals is continuously patterned and generated and output as 321321,. As shown in FIG. 12, when the cam signal count is 3, the cylinder determination is performed by the compression stroke of the third cylinder # 3. When the cam signal count is 2, the compression stroke of the second cylinder # 2 and the cam signal are determined. When the count number is 1, it is determined that the first cylinder # 1 is in the compression stroke.

  In other words, the control unit 100 detects the unequal interval portion 26 based on the signal obtained from the crank angle sensor 13 and counts the number of times of detection, and detects the first time as shown in FIG. The number of signals from the cam angle sensor 14 (detected groups 27A, 27A, 28B) that arrived within the period from the detection of the 30 ° CA interval signal group 26a corresponding to the unequal interval portion 26 to the third detection. Cylinder determination is performed based on a signal group 27a composed of three signals, a signal group 27b composed of two signals, and a signal group 27c composed of one signal corresponding to 27B and 27C.

  In addition, when counting the number of detections of the unequal interval portion 26, a case where a signal has not arrived from the cam angle sensor 14 within a predetermined time (or angle) before and after the unequal interval portion 26 is detected. The first count is newly performed, and when the third count is detected, counting beyond that is stopped, and a new cylinder determination is performed (see FIG. 11).

  Thus, even in an odd-cylinder engine such as a three-cylinder engine as in the present embodiment, the cylinder determination can be performed quickly without error.

  Further, since the crank angle sensor can be an inexpensive magnetic type, Hall element type, magnetoresistive element type or the like instead of an expensive optical type, the apparatus cost can be kept low.

  In the above-described embodiment, the signal of the cam angle sensor 14 is counted based on the position of the unequal interval portion 26 detected from the signal of the crank angle sensor 13. If the relationship of the number of cam signals generated between unequal intervals is not broken, cylinder determination is established wherever the cam signal is generated. In other words, the cylinder determination device of the present invention does not cause erroneous determination even for an engine having a valve mechanism in which the relative timing between the intake camshaft 62 and the crankshaft 60 changes and the valve timing of the intake and exhaust valves is variable. Cylinder determination can be performed accurately.

  Further, based on the signal obtained from the crank angle sensor 13, the time required for the crankshaft 60 to rotate by a predetermined angle is sequentially measured, and the presence or absence of misfire in each cylinder is determined based on the required time. It is also possible.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic block diagram which shows one Embodiment of the cylinder determination apparatus which concerns on this invention with the vehicle-mounted three-cylinder engine to which it is applied. The figure which shows the internal structure of a control unit. The figure which shows the output characteristic of a crank angle sensor and a cam angle sensor. The figure which shows the example of incorporation in the engine of the said crank angle sensor and the cam angle sensor. The figure which shows the structure of a crank angle sensor typically. The figure which shows the structure of a cam angle sensor typically. The figure which shows the relationship of the stroke of each cylinder of an engine, the crank signal obtained from a crank angle sensor, and the cam signal obtained from a cam angle sensor. The functional block diagram which shows the cylinder determination processing content of a control unit. The figure used for description of the unequal interval part detection method. The figure used for description of the formation method of a cylinder determination window. The figure which shows the relationship of the stroke of each cylinder of an engine, a crank signal, a cam signal, a cylinder determination window, and the cam signal count number between unequal intervals parts. The figure used for description of the cylinder determination based on the number of cam signals.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Engine, 6 ... Fuel injection valve, 7 ... Intake valve, 8 ... Exhaust valve, 9 ... Ignition coil, 13 ... Crank angle sensor, 13a ... Circular rotating member for crankshafts, 13b ... Crankshaft detector, 14 ... cam angle sensor, 14a ... camshaft circular rotating member, 14b ... camshaft detector, 15 ... detected portion, 25 ... equally spaced portion, 26 ... unequally spaced portion, 27A, 27B, 27C ... detected portion group, 60 ... crankshaft, 62, 65 ... camshaft, 100 ... control unit

Claims (7)

The crankshaft is rotated integrally with the outer periphery, and a plurality of crankshaft detected parts are arranged at equal angular intervals over a predetermined angle range, and the plurality of crankshaft detected parts are A circular rotating member for a crankshaft in which unevenly spaced portions arranged at an angular interval larger than the equal angular interval are alternately formed by the same number as the number of cylinders of the engine;
A crankshaft detector disposed opposite to the crankshaft circular rotating member and outputting a pulse as a signal each time the equidistant portion is detected according to the rotation of the crankshaft circular rotating member;
A camshaft that is rotated integrally with the camshaft and that has camshaft detected portions having different numbers of camshaft detected portions on the outer peripheral portion at equal intervals to the number of cylinders of the engine. A circular rotating member for
A cam shaft detector disposed opposite to the cam shaft circular rotating member and outputting a pulse as a signal each time the cam shaft detected portion is detected according to the rotation of the cam shaft circular rotating member. When,
An engine cylinder determination device having
The unequal interval portion is detected based on the signal from the crankshaft detector, and every time the unequal interval portion is detected, a cylinder determination window signal is generated, and the cylinder determination window signal is generated. A cylinder determining apparatus for an engine which performs cylinder determination based on a signal from the camshaft detector during a period from when the next cylinder determination window signal is generated. When the camshaft detected portion is detected by the camshaft detector, the crankshaft detected portion of the unevenly spaced portion of the crankshaft circular rotating member is detected by the crankshaft detector. The engine cylinder determination device according to claim 1, wherein the engine cylinder determination device is arranged so as to be in the vicinity of a time detected by the engine. 3. The engine cylinder determining apparatus according to claim 2, wherein the vicinity means that the crank angle is within 15 degrees from a time when the crankshaft detected portion is detected by the crankshaft detector. 4. When the signal from the cam shaft detector does not arrive within a predetermined time before and after the unequal interval portion is detected, the count of the number of detections of the unequal interval portion is started, and the unequal interval is started. When the third time of the part is detected, further counting is stopped, and when the first time and the third time of the unequal interval part are counted, the cylinder judgment window signal is generated to perform the cylinder judgment. The engine cylinder determination device according to any one of claims 1 to 3. When the signal from the cam shaft detector does not arrive within a predetermined angle before and after the unequal interval portion is detected, the count of the number of detections of the unequal interval portion is started, and the unequal interval is started. When the third time of the part is detected, further counting is stopped, and when the first time and the third time of the unequal interval part are counted, the cylinder judgment window signal is generated to perform the cylinder judgment. The engine cylinder determination device according to any one of claims 1 to 3. The time interval of the signal obtained from the crankshaft detector is measured, and is sequentially stored as the previous time interval t3, the previous time interval t2, and the latest time interval t1, and the stored time intervals. Using t3, t2, and t1, t2 / t1> constant value A1 (expression 1) and t2 / t3> constant value A2 (expression 2) are calculated, and both expressions (expression 1) and (expression 2) are calculated. When both are established, it is determined as the unequal interval portion, and when at least one of the two expressions (Equation 1) and (Equation 2) is not established, the unequal interval portion is determined. The cylinder determination device according to any one of claims 1 to 5, wherein an identification detection of a part and the equally-spaced part is performed. Based on the signal obtained from the crankshaft detector, the time required for the crankshaft to rotate by a predetermined angle is sequentially measured, and the presence or absence of misfire in each cylinder is determined based on the required time. The cylinder determination device according to any one of claims 1 to 6 , wherein the cylinder determination device is characterized.

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