JP3963054B2 - Rotation signal abnormality detection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rotation signal abnormality detection apparatus for an internal combustion engine.
[0002]
[Prior art]
In general, an internal combustion engine for a vehicle is provided with a rotation angle sensor that generates a rotation pulse signal at every predetermined rotation angle of the crankshaft and a reference position sensor that detects a predetermined reference position associated with the rotation of the crankshaft. Various controls such as fuel injection and ignition timing are performed according to the detection result.
[0003]
At this time, if an abnormality occurs in each of the sensors and the rotational position of the crankshaft is erroneously detected, the various controls are hindered. Therefore, it is necessary to detect the abnormality and warn the driver to that effect. . In view of this, various methods for detecting an abnormality in a rotation signal by a rotation angle sensor or a reference position sensor have been proposed.
[0004]
As a rotation signal abnormality detection method, for example, as described in Japanese Patent No. 2575606, there is a method of detecting a relative position between a reference position signal and a rotation pulse signal by counting the number of pulses. Specifically, the number of rotation pulse signals between two consecutive reference position signals is counted. If the number of measurement pulses is different from the normal count number, or even if a predetermined pulse signal is counted from the reference position signal, This is a method of determining that the reference position signal is abnormal when the reference signal does not come.
[0005]
As another conventional technique, in Japanese Patent No. 2743579, the number of pulses of the rotation pulse signal by the rotation angle sensor is counted, and the elapsed time from the input of the reference position signal and the input time interval of the reference position signal are measured. The abnormality of the rotation signal is detected from the number of signal pulses and each time. Specifically, when the number of signal pulses is equal to or greater than a predetermined value and the measured elapsed time is longer than a predetermined time determined from the input time interval of the reference position signal, it is determined that the reference position sensor is abnormal, and the signal When the number of pulses is equal to or greater than a predetermined value and the measured elapsed time is shorter than the predetermined time, it is determined that the rotation angle sensor is abnormal.
[0006]
[Problems to be solved by the invention]
However, in any of the above prior arts, since abnormality detection is performed with the number of pulses of the rotation pulse signal from the reference position signal as a starting point, if the original position of the reference position signal is misaligned, an accurate abnormality is detected. There was a problem that detection could not be performed.
[0007]
In other words, the rotation pulse signal usually detects the rotation of the gear rotor directly connected to the crankshaft by the rotation angle sensor, while the reference position signal detects the rotation of the gear rotor directly connected to the camshaft by another rotation angle sensor. To detect. In this case, if the timing belt is mistakenly assembled when the timing belt is assembled to the pulley, the phases of the crankshaft and the camshaft are shifted by the amount of the assembling error. When this phase shift occurs, the devices described in the above publications basically detect anomalies by the number of pulses of the rotation pulse signal, so the resolution is limited by the angular interval between pulses, and the angular interval between pulses is relatively large. (For example, in the case of 30 ° CA), an abnormality of the rotation signal due to the phase shift cannot be detected.
[0008]
The present invention has been made paying attention to the above problems, and an object of the present invention is to provide a rotation signal abnormality detection device capable of accurately detecting a rotation signal abnormality.
[0009]
[Means for Solving the Problems]
The rotation signal abnormality detection device according to the present invention is premised on that the crank rotor rotates as the crankshaft rotates during operation of the internal combustion engine, and the rotation position detection means detects the rotation pulse signal and the missing tooth position. The At the same time, the cam rotor rotates as the cam shaft rotates, and the reference position signal is detected by the reference position detecting means.
[0010]
The invention according to claim 1 is characterized in that the time measurement means for measuring the time interval between the detection of the reference position signal and the detection of the missing tooth position, and the time measurement means are characterized. And an abnormality detecting means for correcting the time with the instantaneous rotational speed at that time and detecting the presence or absence of abnormality of the rotation signal based on the correction result.
[0011]
If the internal combustion engine is at the same rotation speed and the reference position on the cam rotor (cam shaft) is shifted from the rotational position on the crank rotor (crank shaft), the reference position signal is detected and the missing tooth position is detected. The time interval between and fluctuates, and the abnormality of the rotation signal can be detected by checking the fluctuation state. At this time, by correcting the time interval (measurement time) between the detection of the reference position signal and the detection of the missing tooth position with the instantaneous rotational speed at that time, the rotation signal can be detected even when the engine rotation state fluctuates. A false detection of abnormalities is avoided.
[0012]
In addition, since a series of abnormality detection is performed at the time interval between pulses, finer abnormality detection is possible compared to conventional devices that detect the abnormality by counting the number of rotation pulses between the reference position signals that precede and follow. Become. That is, abnormality detection can be performed with a resolution finer than the angular interval between pulses. From the above, it is possible to accurately detect abnormality of the rotation signal.
[0013]
Incidentally, if the rotation pulse signal is used as a reference, a deviation of the reference position signal with respect to the same signal is detected. Conversely, if the reference position signal is used as a reference, a deviation of the rotation pulse signal with respect to the same signal is detected.
[0014]
Further, the invention according to claim 2 is characterized in that time measuring means for measuring a time interval between the detection of the reference position signal and the detection of the missing tooth position, and rotation of the camshaft relative to the crankshaft. A phase variable mechanism that controls the opening / closing timing of the intake valve or the exhaust valve by adjusting the phase, and corrects the time measured by the time measuring means with the instantaneous rotational speed at that time, and the camshaft by the phase variable mechanism And an abnormality detecting means for detecting the presence or absence of abnormality of the rotation signal based on the correction result.
[0015]
According to the second aspect of the invention, similarly to the first aspect, it is possible to avoid erroneous detection of an abnormality in the rotation signal even when the engine rotational state fluctuates, and of course, to detect fine abnormality. In addition, the following characteristic actions and effects can be obtained.
[0016]
That is, in recent years, an internal combustion engine equipped with a phase variable mechanism (so-called VVT mechanism) that controls the opening / closing timing of the intake valve or the exhaust valve by adjusting the rotational phase of the camshaft with respect to the crankshaft in order to improve the performance of the internal combustion engine. There are many on the market. In such an internal combustion engine, the phase of the camshaft and the crankshaft always fluctuates. Therefore, even if the existing technology (for example, the above-mentioned Patent Nos. 2575606 and 2743579) is applied, the phase is changed by the phase variable mechanism. Sometimes it becomes impossible to detect an abnormality in the rotation signal. On the other hand, in the present invention, the time interval (measurement time) between the detection of the reference position signal and the detection of the missing tooth position is corrected according to the advance phase of the cam shaft by the phase variable mechanism. The rotation signal abnormality can be detected regardless of the operating state of the variable mechanism. As a result, it is possible to accurately detect an abnormality in the rotation signal.
[0017]
According to a third aspect of the present invention, the abnormality detection means obtains the amount of deviation of the rotation signal from the result of the correction, and determines the presence or absence of abnormality depending on whether or not it is within a predetermined allowable range. To do. In this case, the abnormality determination can be easily performed by determining the abnormality from the amount of deviation of the rotation signal.
[0018]
According to the fourth aspect of the present invention, when it is determined whether or not the amount of deviation of the rotation signal is within the allowable range, the allowable range is the n teeth of the pulley (n = 0, 1, 2, , 3...) Is set to allow the assembly error. That is, for example, if n = 0, an assembly error for one tooth of the pulley is not allowed, and if n = 1, an assembly error for one tooth of the pulley is allowed (hereinafter, n = 2). , 3 ... are the same). In this case, the threshold value for abnormality determination can be arbitrarily set according to the design concept of each internal combustion engine, and desired abnormality detection data can be obtained.
[0019]
However, in this specification, the term “timing belt” includes a belt type in addition to the belt type, and the term “pulley” includes a sprocket (chain gear).
[0020]
The invention according to claim 5 is an apparatus for measuring a time interval between adjacent rotation pulse signals and determining a missing tooth position based on the pulse time interval, wherein the abnormality detecting means is measured by the time measuring means. When the corrected time is corrected with the instantaneous rotational speed at that time, the correction is performed based on the time interval of the rotation pulse signal used at the time of missing tooth determination. In this case, by performing correction based on the time interval of the rotation pulse signal used for the missing tooth determination, it is possible to provide an extremely simple and immediate abnormality detecting device.
[0021]
In the invention according to claim 6, the rotational position detecting means replaces the crank rotor having the missing tooth portion, a rotor having a large number of equally spaced protrusions in the entire outer periphery, and a position corresponding to the missing tooth portion. And the time measuring means measures a time interval between the detection of the reference position signal and the detection of the reference protrusion. This indicates that the configuration for detecting the reference position on the crankshaft side can be embodied in addition to the form of the missing tooth portion, and by detecting the reference protrusion instead of the missing tooth portion. As described above, it is possible to accurately detect the abnormality of the rotation signal.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is an overall configuration diagram showing an engine control apparatus according to the present embodiment. In FIG. 1, an engine 1 is a spark ignition type four-cycle multi-cylinder internal combustion engine, and an intake pipe 2 and an exhaust pipe 3 are connected to an intake port and an exhaust port, respectively. The intake pipe 2 is provided with a throttle valve 4 that is linked to an accelerator pedal (not shown), and an intake pipe pressure sensor 6 is provided in a surge tank 5 of the intake pipe 2.
[0023]
A piston 8 that reciprocates in the vertical direction in the figure is disposed in a cylinder 7 that constitutes a cylinder of the engine 1. A combustion chamber 10 defined by a cylinder 7 and a cylinder head 9 is formed above the piston 8. The combustion chamber 10 communicates with the intake pipe 2 and the exhaust pipe 3 via an intake valve 11 and an exhaust valve 12, respectively. ing. The cylinder 7 (water jacket) is provided with a water temperature sensor 13 for detecting the cooling water temperature.
[0024]
The exhaust pipe 3 is provided with a catalytic converter 14 made of, for example, a three-way catalyst for purifying harmful components (HC, CO, NOx) in the exhaust gas. An O2 sensor 15 is provided on the upstream side of the catalytic converter 14 for outputting different voltage signals on the rich side and the lean side with respect to the stoichiometric air-fuel ratio.
[0025]
The electromagnetically driven injector 16 is supplied with high-pressure fuel from a fuel supply system (not shown), and the injector 16 injects and supplies fuel to the engine intake port when energized. In the present embodiment, a multi-point injection (MPI) system having one injector 16 for each branch pipe of the intake manifold is configured. A spark plug 17 disposed in the cylinder head 9 is ignited by a high voltage for ignition supplied from an igniter (not shown). In this case, fresh air supplied from upstream of the intake pipe and fuel injected by the injector 16 are mixed at the engine intake port, and the mixture flows into the combustion chamber 10 as the intake valve 11 opens. The fuel that has flowed into the combustion chamber 10 is ignited by an ignition spark by the spark plug 17 and is used for combustion.
[0026]
Cam pulleys 21a and 22a are fixed to an intake side camshaft 21 for opening and closing the intake valve 11 at a predetermined timing and an exhaust side camshaft 22 for opening and closing the exhaust valve 12 at a predetermined timing, respectively. A crank pulley 23 a is fixed to 23. A timing belt 24 is assembled to each of the pulleys 21a to 23a, and the cam shafts 21 and 22 rotate at a rate of once per two rotations of the crankshaft 23.
[0027]
A cam rotor 25 is provided on the intake side camshaft 21 so as to be integrally rotatable, and a protrusion 25a is formed at one location on the outer peripheral edge thereof. The reference position sensor 26 is configured as an electromagnetic pickup type sensor, and is disposed so as to face the cam rotor 25 to electromagnetically detect the proximity of the protrusion 25a.
[0028]
Further, a crank rotor 27 is provided on the crankshaft 23 so as to be integrally rotatable, and a plurality of protrusions 27a are formed at equal intervals on the outer peripheral edge thereof. The protrusions 27a are provided at intervals of 10 ° CA, and a part of the protrusions 27a is provided with a missing tooth portion 27b from which two protrusions 27a are missing. The rotation angle sensor 28 is configured as an electromagnetic pickup sensor, and is disposed so as to face the crank rotor 27 to electromagnetically detect the proximity of the protrusion 27a. Each detection signal of the reference position sensor 26 and the rotation angle sensor 28 is shaped into a rectangular pulse signal by a waveform shaping circuit (not shown), and the pulse signal after the waveform shaping is output from each sensor.
[0029]
Here, as also shown in FIG. 2, the reference position sensor 26 is a reference position signal (G signal) which becomes a reference for determining the ignition cylinder every 720 ° CA of the engine 1 as the projection 25a of the cam rotor 25 passes. Is output. The rotation angle sensor 28 outputs a rotation pulse signal (NE signal) every 10 ° CA as the projection 27a of the crank rotor 27 passes. At this time, the missing tooth position corresponding to the missing tooth portion 27b is detected every 360 ° CA, that is, for example, at times t1 and t2 in the figure.
[0030]
Further, the intake camshaft 21 is provided with a hydraulically driven VVT mechanism 29. The VVT mechanism 29 includes a mechanism for adjusting the relative rotational phase between the intake camshaft 21 and the crankshaft 23, and its operation is adjusted according to hydraulic control by a solenoid valve (not shown). That is, the intake camshaft 21 rotates to the retard side or advance side with respect to the crankshaft 23 according to the control amount of the VVT mechanism 29, and the opening / closing timing of the intake valve 11 is retarded in accordance with the operation. Side or advance side.
[0031]
In the present embodiment, the cam rotor 25 and the reference position sensor 26 constitute reference position detection means, and the crank rotor 27 and the rotation angle sensor 28 constitute rotation position detection means. Further, the VVT mechanism 29 constitutes a phase variable mechanism.
[0032]
The electronic control unit (ECU) 30 is configured around a known microcomputer including an I / O port 31, a CPU 32, a ROM 33, a RAM 34, a free-run timer 35, a backup RAM 36, and the like. The ECU 30 receives detection signals from the intake pipe pressure sensor 6, the water temperature sensor 13, the O2 sensor 15, the reference position sensor 26, and the rotation angle sensor 28, and based on the detection signals, the intake pressure, the cooling water temperature, the air temperature. Engine operating conditions such as fuel ratio and engine speed are detected. The ECU 30 controls the fuel injection by the injector 16, the ignition timing by the spark plug 17, and the opening / closing timing of the intake valve 11 by the VVT mechanism 29 based on the various engine operating states detected as described above. .
[0033]
Next, the operation of the present embodiment will be described. First, the opening / closing timing control of the intake valve 11 by the VVT mechanism 29 will be described. However, since the content of the control is not the gist of the present invention, illustration and detailed description thereof are omitted.
[0034]
Briefly describing the VVT control, the opening / closing timing of the intake valve 11 is controlled at the most retarded position before the start of the engine 1 is completed. Further, after the warm-up of the engine 1 is completed, a target advance amount (VVT advance value ADV) of the intake side valve timing is set according to the engine operating state (engine speed, intake pressure, etc.), and the target advance The drive of the VVT mechanism 29 is controlled so as to obtain an angular amount. Alternatively, the well-known VVT feedback control is performed so that the target advance amount of the intake side valve timing set according to the engine operating state matches the actual phase of the camshaft detected by, for example, a sensor or the like. Alternatively, the drive of the VVT mechanism 29 may be feedback controlled.
[0035]
On the other hand, the CPU 32 in the ECU 30 implements the time measuring means and the abnormality detecting means described in the claims. Specifically, the processing of FIGS. 3 and 4 is executed to diagnose the presence / absence of an abnormality in the rotation signal obtained by the reference position sensor 26 or the rotation angle sensor 28.
[0036]
The process shown in FIG. 3 is an interrupt process that is started in response to the input of a reference position signal (G signal). That is, the process of FIG. 3 is performed at intervals of 720 ° CA. In FIG. 3, in step 101, the count-up process of the reference position counter CCAM is started, and then this process is temporarily terminated. Actually, the time when the reference position signal is input is read by the free-run timer 35, and the time from that time is measured as the count value of the reference position counter CCAM.
[0037]
The process shown in FIG. 4 is an interrupt process that is started in response to the input of a rotation pulse signal (NE signal). That is, the process of FIG. 4 is performed at 10 ° CA intervals. In FIG. 4, first, in step 201, it is determined from the time interval of the rotation pulse signal (NE signal) whether or not the current NE interrupt is at the missing tooth position. More specifically, the time interval (pulse time interval) between adjacent rotation pulse signals is measured, and the ratio between the current measurement time Tn and the previous measurement time Tn-1 is greater than a predetermined missing tooth determination value K. It is determined whether or not. That means
Tn / Tn-1> K
It is determined whether or not. Here, the missing tooth determination value K may be about 2.5.
[0038]
When Tn / Tn-1 ≦ K, the routine proceeds to step 202 where the missing tooth flag XCAKE is cleared to “0”, and then this processing is terminated. If Tn / Tn-1> K, the routine proceeds to step 203, where the missing tooth flag XCAKE is set to "1". In the time chart of FIG. 2, for example, step 201 is YES at times t1 and t2 (Tn / Tn-1> K).
[0039]
Thereafter, in step 204, using the following equation (1), the reference position is determined based on the count value of the reference position counter CCAM at the time of this interruption, the pulse time interval Tn (Tn at the time of missing tooth determination), and the VVT advance value ADV. A deviation amount CAMJDG is calculated.
CAMJDG = (CCAM / Tn)-(ADV / 360) (1)
According to the above equation (1), the count value of the reference position counter CCAM, that is, the time interval between the reference position signal and the missing tooth position is corrected by the pulse time interval Tn. This means that the CCAM value is corrected at the instantaneous rotational speed at that time. Furthermore, correction is performed using the VVT advance value ADV, and the reference position deviation amount CAMJDG is calculated as a result of each correction.
[0040]
At this time, as shown in FIG. 2A, if the VVT advance value ADV is “0” (in the case of the most retarded angle), the count value of the reference position counter CCAM becomes “CCAM1”, and CCAM = CCAM1 , ADV = 0 is substituted into the above equation (1) to calculate the reference position deviation amount CAMJDG.
[0041]
As shown in FIG. 2B, when the VVT advance value ADV is “ADV1”, the count value of the reference position counter CCAM is “CCAM2”, and CCAM = CCAM2 and ADV = ADV1 are set to (1 The reference position deviation amount CAMJDG is calculated by substituting it into the equation (1).
[0042]
Thereafter, in step 205, it is determined whether or not the calculated reference position deviation amount CAMJDG is within a predetermined normal range TOKL to TOKH. As an example, an allowable value of deviation of the reference position signal is set to “−10 ° CA to + 10 ° CA”, and a TOKL value and a TOKH value for defining a normal range are set while corresponding to the allowable value.
[0043]
However, the setting of the TOKL value and the TOKH value may be arbitrary, and the allowable deviation of the reference position signal may be changed to “−20 ° CA to + 20 ° CA” or the like. For example, when the timing belt 24 is assembled to the pulleys 21a to 23a and the assembly error is allowed by n teeth of the pulley, the TOKL value and the TOKH value are set accordingly (n = 0, 1, 2). , 3 etc.).
[0044]
If step 205 is YES, it is considered that the reference position signal is normal, and the abnormality flag XCAMF is cleared to “0” in step 206. On the other hand, for example, if the assembly error of the timing belt 24 exceeds the allowable range, step 205 is NO. In this case, it is considered that the reference position signal is abnormal, and “1” is set to the abnormality flag XCAMF in step 207.
[0045]
In the above-described abnormality diagnosis, the reference position deviation amount CAMJDG is subjected to the rotation speed correction and the VVT advance angle correction as described above, so that erroneous detection of the reference position signal deviation is avoided. Yes.
[0046]
After the operation of the abnormality flag XCAMF, in step 208, the reference position counter CCAM is cleared to “0”, and then this process ends. When “1” is set in the abnormality flag XCAMF, a warning lamp (not shown) is lit to warn the driver or the like that an abnormality has occurred. In addition, diagnostic information indicating a deviation in the reference position signal is stored in the backup RAM 36.
[0047]
Incidentally, even at time t2 in FIG. 2, it is determined from the time interval of the rotation pulse signal that the tooth is missing (step 201 in FIG. 4 is YES), but in this case, it is not immediately after the input of the reference position signal. Therefore, the processing after step 204 is not performed. That is, the rotation signal abnormality detection is performed at the time of missing tooth detection immediately after the reference position signal is input (every 720 ° CA).
[0048]
According to the embodiment described in detail above, the following effects can be obtained.
(A) The time interval from the detection of the reference position signal to the detection of the missing tooth position (count value of the reference position counter CCAM) is corrected by the instantaneous rotational speed (pulse time interval Tn at the missing tooth position) at that time. The correction is made in accordance with the advance phase of the camshaft 21 by the VVT mechanism 29, and the presence or absence of an abnormality in the rotation signal is detected based on the correction result. In short, when the engine speed is basically the same, an abnormality in the rotation signal can be detected from the fluctuation state of the count value of the reference position counter CCAM. In addition, by correcting the count value of the reference position counter CCAM with the instantaneous rotational speed and the advance amount of the VVT mechanism 29 at that time, when the engine rotation state fluctuates or when the VVT mechanism 29 is activated. False detection of rotation signal abnormality is avoided. As a result, it is possible to accurately detect an abnormality in the rotation signal.
[0049]
In addition, as described above, since a series of abnormality detection is performed by the time interval between pulses, the number of rotation pulses between the reference position signals before and after is counted and the abnormality is finer compared with the conventional device that detects abnormality by the number of pulses. Detection is possible. In other words, when anomaly detection is performed with the number of rotation pulses, the resolution is limited by the angular interval between pulses, whereas the apparatus of this embodiment performs anomaly detection with a resolution finer than the angular interval between pulses. it can. Therefore, it is particularly suitable for an apparatus that employs the VVT mechanism 29 that linearly controls the rotational phase of the cam shaft 21.
[0050]
In the case of this configuration, even when the angular interval of the rotation pulse signal is relatively large (for example, 30 ° CA), fine abnormality detection can always be performed regardless of the angular interval.
[0051]
(B) The reference position deviation amount CAMJDG is obtained from the results of the rotation speed correction and the VVT advance amount correction, and the presence / absence of an abnormality is determined depending on whether or not it is within a predetermined allowable range. Therefore, the abnormality determination can be easily performed.
[0052]
(C) When determining whether or not the reference position deviation amount CAMJDG is within the allowable range, the allowable range allows an assembly error of n teeth (n = 0, 1, 2, 3...) Of the pulley. Set as In this case, the threshold value for abnormality determination can be arbitrarily set according to the design concept of each engine, and desired abnormality detection data can be obtained. For example, an abnormality in the rotation signal when the timing belt 24 is mistakenly assembled can be reliably detected. Therefore, the driver 1 is appropriately warned of the abnormality, thereby avoiding the inconvenience of causing the engine 1 to malfunction.
[0053]
(D) When correcting the count value of the reference position counter CCAM with the instantaneous rotational speed at that time, the correction is performed based on the pulse time interval (Tn at time t1 in FIG. 2) used at the time of missing tooth determination. It is possible to provide an abnormality detection device that is extremely simple and effective.
[0054]
The embodiment of the present invention can be embodied in the following form in addition to the above.
In the above embodiment, the pulse time interval Tn at the missing tooth position is used when correcting according to the instantaneous rotational speed at that time, but this configuration is changed. For example, according to the relationship shown in FIG. 5, a rotational speed correction value F corresponding to the engine rotational speed at that time is obtained, and the reference position deviation amount CAMJDG is calculated using the correction value F. Actually, the equation (1) is
CAMJDG = CCAM · F− (ADV / 360) (2)
Then, abnormality detection may be performed based on the reference position deviation amount CAMJDG calculated from the equation (2). Also in this configuration, the abnormality of the rotation signal can be accurately detected as in the above-described embodiment.
[0055]
In the above embodiment, the VVT mechanism 29 is provided on the intake camshaft 21 and the phase of the camshaft 21 is adjusted, but this configuration is changed. For example, the exhaust camshaft 22 is also provided with a VVT mechanism, and the exhaust camshaft 22 is provided with a reference position sensor so that an abnormality in the rotation signal is detected based on a detection signal from the exhaust side reference position sensor. Good.
[0056]
Further, it can be applied to an engine having no VVT mechanism. In this case, correction according to the VVT advance value is not necessary for abnormality diagnosis of the rotation signal. Therefore, the equation (1) is
CAMJDG = CCAM / Tn (3)
Then, abnormality detection may be performed based on the reference position deviation amount CAMJDG calculated from the equation (3). Alternatively, in the case of the equation (2) using the rotation speed correction value F corresponding to the engine rotation speed,
CAMJDG = CCAM · F (4)
Then, the abnormality detection may be performed based on the reference position deviation amount CAMJDG calculated from the equation (4). In any of these cases, the abnormality of the rotation signal can be accurately detected.
[0057]
Even if a VVT mechanism is provided on one of the intake side or the exhaust side camshaft and a reference position sensor is provided on the other (one with no VVT function), the correction according to the VVT advance value is not required. Anomaly detection may be performed based on the reference position deviation amount CAMJDG calculated from the equation (3) or the equation (4).
[0058]
In the above embodiment, the time interval from the detection of the reference position signal to the detection of the missing tooth position (the count value of the reference position counter CCAM), that is, the time from the reference position on the camshaft side to the reference position on the crankshaft side is measured. The measured time was corrected by the instantaneous rotational speed at that time, but on the contrary, the time interval from the detection of the missing tooth position to the detection of the reference position signal (from the reference position on the crankshaft side to the camshaft). (Time to the reference position on the side) may be measured, and the measured time may be corrected with the instantaneous rotational speed at that time.
[0059]
In the above embodiment, the crank rotor 27 is provided with the missing tooth portion 27b as a configuration of the rotational position detecting means, and the position of the missing tooth portion 27b is detected by the rotation angle sensor 28. However, this configuration is changed. As shown in FIG. 6, two rotors 41 and 42 are provided on the crankshaft 23, and a large number of protrusions 41 a are formed at equal intervals on the entire outer periphery of one rotor 41, while a reference protrusion is formed on the other rotor 42. 42a is formed in one place. Then, the rotation of one rotor 41 is detected by the first sensor 43, and the rotation of the other rotor is detected by the second sensor 44.
[0060]
Also in this case, as shown in FIG. 2, rotation pulse signals at equiangular intervals (for example, every 10 ° CA) are obtained, and a crankshaft side reference signal is obtained every 360 ° CA, for example. This indicates that the configuration for detecting the reference position on the crankshaft 23 side can be embodied in addition to the form of the missing tooth portion, and the reference protrusion 42a is detected instead of the missing tooth portion. This makes it possible to accurately detect the abnormality of the rotation signal as described above.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an outline of an engine control apparatus according to an embodiment of the invention.
FIG. 2 is a time chart showing various signal waveforms.
FIG. 3 is a flowchart showing interrupt processing of a reference position signal (G signal).
FIG. 4 is a flowchart showing interrupt processing of a rotation pulse signal (NE signal).
FIG. 5 is a diagram for setting a rotation speed correction value F in another embodiment.
FIG. 6 is a diagram showing a configuration of rotational position detection means in another embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Engine, 11 ... Intake valve, 12 ... Exhaust valve, 21 ... Intake side camshaft, 22 ... Exhaust side camshaft, 23 ... Crankshaft, 21a-23a ... Pulley, 24 ... Timing belt, 25 ... Reference position detection means , 26... Reference position sensor constituting reference position detection means, 27... Crank rotor constituting rotation position detection means, 27 b... Missing tooth portion, 28... Rotation angle sensor constituting rotation position detection means, 29 ... VVT mechanism as a phase variable mechanism, 30... ECU, 32... CPU constituting time measuring means and abnormality detecting means, 41 and 42... Rotor constituting rotational position detecting means, 43 and 44. First and second sensors.

Claims (6)

A crank rotor provided on a crankshaft of an internal combustion engine, for generating a rotation pulse signal for each predetermined rotation angle of the crankshaft, and a rotation pulse signal indicating a position of a predetermined toothless portion provided on the crank rotor; Rotational position detecting means for detecting from the time interval of,
A reference position detecting means having a cam rotor provided on a camshaft that rotates at a rate of once per two rotations of the crankshaft, and generating a reference position signal at a predetermined rotational position of the camshaft;
Time measuring means for measuring a time interval between the detection of the reference position signal and the detection of the missing tooth position;
Rotation signal abnormality detection, comprising: an abnormality detection means that corrects the time measured by the time measurement means at the instantaneous rotational speed at each time and detects the presence or absence of abnormality of the rotation signal based on the correction result. apparatus. A crank rotor provided on a crankshaft of an internal combustion engine, for generating a rotation pulse signal for each predetermined rotation angle of the crankshaft, and a rotation pulse signal indicating a position of a predetermined toothless portion provided on the crank rotor; Rotational position detecting means for detecting from the time interval of,
A reference position detecting means having a cam rotor provided on a camshaft that rotates at a rate of once per two rotations of the crankshaft, and generating a reference position signal at a predetermined rotational position of the camshaft;
Time measuring means for measuring a time interval between the detection of the reference position signal and the detection of the missing tooth position;
A phase variable mechanism that controls the opening / closing timing of the intake valve or the exhaust valve by adjusting the rotational phase of the camshaft relative to the crankshaft;
The time measured by the time measuring means is corrected at the instantaneous rotational speed at that time, and is corrected according to the advance phase of the camshaft by the phase variable mechanism, and the presence or absence of an abnormality in the rotation signal is determined based on the correction result. An abnormality detecting device for a rotation signal, comprising: an abnormality detecting means for detecting. 3. The abnormality detection unit according to claim 1, wherein the abnormality detection unit obtains a deviation amount of the rotation signal from the correction result, and determines whether there is an abnormality depending on whether the rotation signal is within a predetermined allowable range. Rotation signal abnormality detection device. Applied to an internal combustion engine in which a pulley is fixed to the crankshaft and the camshaft, and a timing belt is assembled to the pulley.
When determining whether or not the amount of deviation of the rotation signal is within an allowable range, the allowable range is set to allow an assembly error of n teeth (n = 0, 1, 2, 3...) Of the pulley. The rotation signal abnormality detection device according to claim 3. An apparatus for measuring a time interval between adjacent rotation pulse signals and determining a missing tooth position based on the pulse time interval, wherein the abnormality detection means instantaneously rotates the time measured by the time measurement means. 3. The rotation signal abnormality detection device according to claim 1, wherein when correcting by speed, the correction is performed based on a time interval of the rotation pulse signal used at the time of missing tooth determination. The rotation position detecting means replaces the crank rotor having the missing tooth portion, and has a rotor having a large number of equally spaced projections in the entire outer periphery and a reference projection provided at a position corresponding to the missing tooth portion. And
The rotation signal abnormality detection device according to claim 1, wherein the time measuring unit measures a time interval between the detection of the reference position signal and the detection of a reference protrusion.

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