JP4333552B2 - Engine control device - Google Patents

Description

  The present invention relates to an engine control apparatus that sequentially measures the rotation angle of a crankshaft of an engine and controls the engine based on the measurement result.

  2. Description of the Related Art Conventionally, in an engine control device, an engine that rotates at a ratio of 1/2 with respect to a crankshaft rotation signal (NE signal) output from a crankshaft sensor according to the rotation of the crankshaft of the engine and the rotation of the crankshaft. Based on the cylinder discrimination signal (G signal) output from the camshaft sensor according to the rotation of the camshaft, the rotation angle of the crankshaft is sequentially measured to perform fuel injection control, ignition timing control, and the like.

  More specifically, the crankshaft rotation signal is pulsed every time the crankshaft rotates by a predetermined angle (for example, 10 ° CA (crank angle)) when the rotation position of the crankshaft is other than a preset reference position. Produce. Further, when the crankshaft is at the reference position, a missing tooth with a missing pulse is generated until the crankshaft rotates at an angle larger than a predetermined angle (for example, 30 ° CA).

  In the cylinder discrimination signal, for example, the logic level changes from a high level to a low level or from a low level to a high level at the occurrence interval of missing teeth in the crankshaft rotation signal.

  In the engine control device, every time the CPU that executes various processes to be executed by the engine control device detects a valid edge (generally a rising edge) of the crankshaft rotation signal, an interrupt process is performed. In addition to counting up the count value of the counter indicating the rotation angle of the crankshaft, the missing tooth detection for detecting the missing tooth of the crankshaft rotation signal is performed, and when the missing tooth is detected, depending on the logic level of the cylinder discrimination signal By setting the count value, the rotation angle of the crankshaft is sequentially measured. The crankshaft rotation signal output from the crankshaft sensor and the cylinder discrimination signal output from the camshaft sensor are analog signals. The engine control device performs waveform shaping when these signals are input, and these signals Is binarized.

  Here, in general, in such an engine control device, the effective edge generation interval in the crankshaft rotation signal is sequentially measured to calculate a ratio with the previous measurement result, and this calculation ratio is a predetermined determination ratio. When the missing tooth determination condition such as above is satisfied, it is determined that a missing tooth is detected.

  However, if the CPU counts up and detects missing teeth in this way, the CPU executes the fuel injection control, ignition timing control, etc. at high frequency when the engine must be executed at high frequency. The load on the power to be processed increases significantly.

Therefore, in order to solve this problem, at the start of the engine where the engine rotation is unstable and the effective edge generation interval fluctuates greatly and it is difficult to detect missing teeth with a certain judgment ratio, the CPU is not able to detect the lack of complicated processing. While detecting the teeth and counting up the count value, the engine rotation is stable and the processing interval provided separately from the CPU is at the time of high engine rotation when the effective edge generation interval falls within a certain range. An engine control device has been devised that performs simple missing tooth detection using a fixed determination ratio and count-up of a count value (see, for example, Patent Document 1).
JP 2004-3454 A

  By the way, the vehicle usually has various countermeasures against noise radiated from mounted electrical components, and transient voltage drop caused by electrical component operation. It is rare that noise that exceeds the threshold value of the waveform shaping circuit in the engine control device is superimposed on the crankshaft rotation signal that is generated, or that the output is reduced such that the threshold value of the waveform shaping circuit cannot be exceeded.

  Further, as described above, the engine control device sets the count value that should be originally taken by the counter in accordance with the logic level of the cylinder discrimination signal when detecting missing teeth. Even if an error occurs in the count value, the count value is corrected to the original count value at the next missing tooth detection.

  However, when performing simple missing tooth detection using a certain determination ratio, as shown in FIG. 20, when noise exceeding a threshold is superimposed on the occurrence interval of effective edges where missing teeth are not generated. Missing tooth determination conditions are easily established, and erroneous detection of missing teeth is likely to occur. FIG. 20 is a timing chart showing an example when noise is superimposed on the crankshaft signal at a timing at which the missing tooth determination condition is satisfied.

  In addition, as shown in FIG. 21, when the engine speed decreases and the effective edge generation interval gradually increases, such as when the vehicle is decelerated, the output from the crankshaft sensor becomes the threshold value of the waveform shaping circuit. If the pulse is missing without exceeding the limit, or if the pulse is missing continuously even if the engine speed is constant, the missing tooth detection condition is likely to be satisfied, and erroneous detection of missing teeth is likely to occur. . FIG. 21 is a timing chart showing an example of a case where the output decrease of the crankshaft rotation signal occurs so that the missing tooth determination condition is satisfied.

  Then, when erroneous detection of missing teeth occurs in this way, the count value corresponding to the logical level of the cylinder discrimination signal is set despite the timing being different from the missing tooth detection timing. There arises a problem that the count value of the counter causes a large error with respect to the count value that should be taken.

  As one of the solutions to such a problem, it is conceivable to provide a logic circuit or the like for discriminating erroneous detection of missing teeth in the engine control device. As a result, it can be considered that the scale and cost of the engine control device become large.

  Therefore, the present invention provides an engine control device that can prevent a large error from occurring in the count value indicating the rotation angle of the crankshaft due to erroneous detection of missing teeth, although having a simple configuration. The purpose is to do.

  In order to achieve the above object, the engine control apparatus according to claim 1, wherein when the rotational position of the crankshaft of the engine is other than a preset reference position, a pulse is generated each time the crankshaft rotates by a predetermined angle. When the crankshaft is at the reference position, a crankshaft rotation signal that causes missing teeth with missing pulses until the crankshaft rotates at an angle greater than a predetermined angle is input to the first counter. The count value is counted up at the valid edge of the pulse in the signal, and the measurement result of the rotation angle of the crankshaft is indicated by this count value. On the other hand, the generation interval measurement means sequentially measures the effective edge generation interval, and the missing tooth detection means sequentially calculates the ratio between the current measurement result of the generation interval measurement means and the previous measurement result. The missing tooth is detected based on the calculated ratio and a judgment ratio set in advance to judge whether or not a missing tooth has occurred between the effective edges.

  And, when the count value of the first counter is a value that can be taken when a deviation within a designated number specified in advance occurs at the correction timing based on the missing tooth detection timing of the missing tooth detection means, The correction actuating means activates the correcting means, and the correcting means corrects the count value of the first counter to the original value that the count value of the first counter should originally take at the correction timing.

  In other words, in this engine control device, if the number of noises and the number of missing effective edges that may occur in the crankshaft rotation signal is measured in advance and the specified number is set, the first will be caused due to false detection of missing teeth. Even when the timing at which the counter value of the counter causes a large error becomes the correction timing, the count value is not corrected to an incorrect original value.

That is, according to the engine control device, the count value of the first counter, the count value when a value that can be taken when a deviation within specified number occurs with a simple configuration that corrects the original value Nevertheless, it is possible to prevent a large error from occurring in the count value indicating the rotation angle of the crankshaft due to erroneous detection of missing teeth.

The “count value of the first counter” may be the count value set in the first counter or the count value immediately before being set in the first counter.
The “designated number” may be different depending on whether the count value of the first counter is shifted to the plus side or the minus value.

  In this engine control device, either or both of the rising edge and the falling edge of the pulse in the crankshaft rotation signal may be effective edges, and when both are effective edges, the crankshaft Can be measured more finely (that is, the measurement resolution can be improved).

  However, in the above-described engine control device, when more noise than the specified number or missing of valid edges occurs in the crankshaft rotation signal, the count value cannot be corrected, and the actual crankshaft rotation angle and A large error remains during the period.

Therefore , in the engine control apparatus according to claim 1, the correction actuating means is configured to change the first counter at the current correction timing even when the count value of the first counter is a value that can be taken when a deviation exceeding the specified number occurs. The difference between the count value of one counter and the count value of the first counter at the previous correction timing is calculated, and if the calculated difference is equal to the count value corresponding to the missing tooth occurrence interval, the correction means is activated. It is set to.

  That is, if the current correction timing or the previous correction timing is due to erroneous detection of missing teeth, the count value of the first counter at the current correction timing and the first count value at the previous correction timing The difference between them is unequal to the count value corresponding to the missing tooth occurrence interval. On the other hand, if the current correction timing and the previous correction timing are due to the detection of the original missing tooth, and if no new noise or missing active edge occurs during that time, the specified number of count values of the first counter Even when a deviation exceeding 1 is generated, the difference between the count value of the first counter at the current correction timing and the count value of the first counter at the previous correction timing becomes equal to the missing tooth occurrence interval.

Therefore, if the correction operation means is set as described above, the count value can be corrected to the original value at the correction timing caused by the original missing tooth detection even if a deviation exceeding the specified number occurs.
Even if the current correction timing and the previous correction timing are due to the original missing tooth detection, even if a new shift occurs, a new shift will occur after the next correction timing. If no further occurs, the count value can be corrected to the original value after the next correction timing.

  Here, when the specified number is equal to or more than two counts of the first counter, for example, although the number of noise occurrences and the number of missing valid edges is equal to one count of the first counter, for example. The timing at which the count value of the first counter becomes a value that can be taken when there is a deviation of two counts or more due to erroneous detection of missing teeth is the correction timing, and the count value is corrected to the original value. In the event of a failure, a new error will occur.

Therefore, it is desirable that the deviation within the specified number is equal to the number of occurrences of one valid edge as described in claim 2 .
In particular, when this is applied to the engine control device according to claim 1 , when the deviation of the count value of the first counter is one occurrence of the valid edge, the first counter When the count value can be corrected to the original value and the deviation of the count value of the first counter is equal to or greater than the number of occurrences of two valid edges, the count of the first counter is performed at the next and subsequent correction timings. The value can be corrected to the original value. That is, the count value of the first counter can be corrected to the original value without causing a new error.

By the way, in any of the above-described engine control devices, as described in claim 3, the level discrimination means for discriminating the level of the cylinder discrimination signal whose level changes according to the rotational position of the cam shaft of the engine, and the cylinder discrimination signal It is preferable to include a first setting unit that sets an original value corresponding to a determination result of the level determining unit among a plurality of types of original values preset according to the level.

By configuring the engine control device in this way, the original value can be set according to the level of the cylinder discrimination signal.
On the other hand, as described in claim 4 , among the plural kinds of original values preset in accordance with the correction timing, the one closest to the count value of the first counter is set as the original value. Two setting means may be provided.

By configuring the engine control device in this way, the original value can be set without determining the level of the cylinder discrimination signal as described above.
In the engine control device according to claim 5, a second counter that receives the crankshaft rotation signal, counts up the count value at the valid edge, and resets the count value to 0 at the missing tooth detection timing is provided. The timing at which the count value of the second counter reaches a designated count value other than 0 designated in advance is used as the correction timing .

  In the engine control apparatus configured as described above, the count value of the second counter is reset to 0 not only when the original missing tooth is detected but also when the missing tooth is erroneously detected. If set, the count value of the second counter does not reach the specified count value from the erroneous detection of the missing tooth until the original missing tooth detection is reached.

  That is, in the above-described engine control apparatus that does not include the second counter, even when the correction timing due to the erroneous detection of the missing tooth occurs, the count value of the first counter deviates within the specified number. However, in the engine control device of the present invention, the count value is set only at the correction timing caused by the original missing tooth detection. It can be corrected to the original value.

In the engine control device according to claim 6, the second counter that receives the crankshaft rotation signal, counts up the count value at the effective edge, and resets the count value to 0 at the missing tooth detection timing is provided. And a count value acquisition means for acquiring the count value of the first counter and the count value of the second counter between the correction timings, and the count value of the first counter acquired by the count value acquisition means And a correction permitting means for comparing the count values of the second counter and permitting the operation of the correction actuating means only when the count values are inconsistent with each other .

  In other words, since the first counter and the second counter count up each count value at the same effective edge, although the count values should normally match each other, false detection of missing teeth When this occurs, the count value of the second counter is reset, resulting in a mismatch with the count value of the first counter.

Therefore, if the engine control apparatus is configured as described above, it is possible to prevent the count value of the first counter from being corrected to an incorrect value even when erroneous detection of missing teeth occurs.
Here, when the engine has two cycles, the count range of the first counter and the count range of the second counter are the same. "

  When the engine has four cycles, the count range of the first counter corresponds to 0 ° CA to 720 ° CA in the rotation angle of the crankshaft, while the count range of the second counter is , Corresponding to 0 ° CA to 360 ° CA. Therefore, in this case, a case where an error corresponding to a value other than 360 ° CA occurs between these count values is referred to as “mismatch”.

  Here, when the count value acquisition means is realized by sequential processing by the CPU (that is, when the count value of the first counter and the count value of the second counter are acquired sequentially rather than simultaneously), the acquisition timing shifts. From this, the correction permission means erroneously determines that these count values are inconsistent even though the count value of the first counter is actually matched with the count value of the second counter ( It is conceivable that a situation in which it is erroneously determined to be consistent (see FIG. 19B) may occur despite the mismatch.

Therefore, in this case, in the engine control apparatus according to the sixth aspect, the count value acquisition means includes the count value of the first counter and the second counter at a time interval shorter than the minimum time of occurrence intervals of the valid edges. And at least three count values are alternately obtained, and the correction permission means counts the count value of one counter that has acquired a plurality of count values among the count value of the first counter and the count value of the second counter. It is set to operate only when the values match .

  If the count value acquisition unit and the correction permission unit are set in this way, the correction operation unit is actually used even though the count value of the first counter matches the count value of the second counter. It is possible to prevent the operation of.

  However, since the effective edge and the acquisition timing are asynchronous with each other, an effective edge is generated while the count value acquisition unit is acquiring the count value, and this is acquired from the same counter. It is conceivable that a situation occurs in which a plurality of count values do not match.

Therefore, as described in claim 7 , the engine control device described above calculates a plurality of count values among the count value of the first counter acquired by the count value acquisition means and the count value of the second counter. It is desirable to provide a reactivation means for reactivating the count value acquisition means when the acquired count values of one counter do not match.

If the engine control device is configured in this way, the count value can be repeatedly acquired until the count values of one counter that has acquired a plurality of count values match each other, and thus the count value of the first counter. And the count value of the second counter can be reliably determined.
Further, in the engine control apparatus according to any one of claims 5 to 7, as described in claim 8, the correction actuating means can take when the count value of the first counter exceeds a specified number. Even if it is a value, the difference between the count value of the first counter at the current correction timing and the count value of the first counter at the previous correction timing is calculated, and the calculated difference corresponds to the missing tooth occurrence interval. If it is equal to the count value to be performed, it is desirable to set the correction means to operate.

By the way, as described in claim 9 , each of the engine control devices described above generates a multiplied clock signal having a period obtained by dividing the previous measurement result of the generation interval measuring means by a preset multiplication number as one cycle. It is preferable to include a multiplied clock generation means and a third counter that counts up the count value to the multiplied number by the multiplied clock signal and resets the count value to 0 at the valid edge.

  In other words, since the rotation angle of the crankshaft in the effective edge generation interval can be measured by the multiplied clock generation means and the third counter, the upper value of the rotation angle of the crankshaft is indicated by the count value of the first counter, and the third counter By indicating the count value of the counter below the rotation angle of the crankshaft, the rotation angle of the crankshaft can be shown more finely (that is, the measurement resolution can be improved).

  In this case, since the count value of the third counter is cleared at the valid edge, it is not necessary to correct the count value of the third counter to the count value corresponding to the original value at the correction timing.

Further, the multiplication clock generation means may be the same as the generation interval measurement means used by the missing tooth detection means to calculate the calculation ratio, or may be a separate one .

By the way, as described in claim 10 , the missing tooth detecting means is realized by using software, and includes a first missing tooth detecting means for detecting missing teeth, a calculation ratio, and a predetermined fixed determination ratio. Based on the above, the second missing tooth detecting means for detecting missing teeth and the first missing tooth detecting means are operated until the rotational speed of the crankshaft per unit time reaches a designated rotational speed designated in advance. After reaching the designated rotational speed, it is preferable to provide switching means for operating the second missing tooth detecting means instead of the first missing tooth detecting means.

  In other words, if the engine rotation (that is, crankshaft rotation) is unstable and the effective edge generation interval fluctuates significantly, missing teeth can be detected quickly through complex software processing. Is stable, and missing teeth can be easily detected at a rotational speed where the effective edge generation interval falls within a certain range.

Moreover, since the first missing tooth detecting means is realized by software, the scale of the engine control device is not increased.
The second missing tooth detection means may also be realized using software in the same manner as the first missing tooth detection means, but when executed by a CPU that performs fuel injection control or ignition timing control, The processing load of the CPU is significantly increased at the time of high engine rotation at which these controls must be performed at a high frequency.

Therefore, it is desirable that the second missing tooth detection means is realized using hardware as described in claim 11 .
That is, since missing teeth are detected using a certain ratio, it can be simply realized by hardware, and the processing load of the CPU at the time of high engine rotation is not increased.

Embodiments of the present invention will be described below with reference to the drawings.
[First Embodiment]
First, FIG. 1 is a configuration block diagram showing a configuration of an engine control apparatus (hereinafter referred to as “engine ECU”) 1 in the present embodiment. In this embodiment, the engine ECU 1 controls an in-line four-cylinder four-stroke one-cycle engine (so-called four-cycle engine).

  As shown in FIG. 1, the engine ECU 1 receives a microcomputer (hereinafter simply referred to as “microcomputer”) 2 that executes various processes for controlling the engine and an input signal from an external device, and inputs it to the microcomputer 2. Input circuits 3, 4, 5, and 6 and an output circuit 7 that receives an output signal from the microcomputer 2 and operates an external device.

  Here, the input circuit 3 is connected to the crankshaft sensor 8 and removes noise in a certain frequency band from the crankshaft rotation signal (NE signal) input from the crankshaft sensor 8 and converts the NE signal into a rectangular wave. The waveform is shaped and input to the microcomputer 2. The crankshaft sensor 8 is provided opposite to the outer periphery of the rotor 10 fixed to the crankshaft 9 of the engine, and is formed on the outer periphery of the rotor 10 at intervals of a predetermined angle (10 ° CA in this embodiment). It is configured as a photoelectric or Hall IC sensor that detects a tooth 101 and generates a pulse. However, one missing tooth portion 102 from which two teeth 101 are missing is provided on the outer periphery of the rotor 10.

  For this reason, the NE signal (NE10 signal) input to the microcomputer 2 via the input circuit 3 generates a pulse every time the crankshaft 9 rotates 10 ° (every 10 ° CA), and the toothless portion of the rotor 10. When 102 reaches the reference position facing the crankshaft sensor 8, the interval between the effective edges of the pulses (rising edge in this embodiment) is three times as long (that is, 30 ° CA). This results in missing teeth with missing pulses (see, eg, FIG. 4). Since the rotor 10 is provided with only one missing tooth portion 102 as described above, a missing tooth is generated every 360 ° CA in the NE10 signal.

  The input circuit 4 is connected to the camshaft sensor 11 and removes noise in a certain frequency band from the cylinder discrimination signal (G signal) input from the camshaft sensor 11 and shapes the G signal into a rectangular wave. And input to the microcomputer 2. The camshaft sensor 11 is provided opposite to the outer periphery of the rotor 13 fixed to the camshaft 12 of the engine that rotates at a ratio of 1/2 with respect to the rotation of the crankshaft 9, and is formed on the outer periphery of the rotor 13. The sensor is configured as a magnetoresistive element (MRE) type sensor in which the logic level of the G signal changes between a high level and a low level in accordance with the unevenness. However, irregularities are alternately formed on the outer periphery of the rotor 13 at intervals of 60 °.

  For this reason, the G signal input to the microcomputer 2 via the input circuit 4 is inverted in logic level three times during the NE10 signal pulse generation period, and at the NE10 signal missing tooth generation timing, at each timing. The logic levels are alternately different (see FIG. 4). However, in this embodiment, the logical level of the G signal is low when the rotation angle of the crankshaft 9 is 360 ° CA, and is high when the rotation angle is 720 ° CA (0 ° CA).

  The input circuit 5 is connected to switches related to engine operation, such as a starter switch 14 for starting the engine and an idle switch 15 for detecting the accelerator pedal fully closed. Band noise is removed, and these input signals are input to the microcomputer 2.

  The input circuit 6 also includes an air flow meter 16 that detects the intake air intake amount of the engine, a throttle sensor 17 that detects the opening of the engine throttle valve, a water temperature sensor 18 that detects the temperature of the engine coolant, and the like. It is connected to various sensors that detect states, and is configured to remove noise in a certain frequency band from input signals from these sensors and to input these input signals to the microcomputer 2.

  The output circuit 7 includes an igniter 19 for switching the four ignition coils 41, 42, 43, 44 provided in each cylinder of the engine, and four fuel injection valves 51, 52, provided in each cylinder of the engine. The igniter 19 and the fuel injection valves 51 to 54 are operated according to the output signal output from the microcomputer 2, respectively.

  Then, the microcomputer 2 indicates the rotation angle of the crankshaft 9 and the crank processing unit 20 that measures the rotation angle of the crankshaft 9 based on the NE10 signal and the G signal input via the input circuits 3 and 4. The front counter 21, the back counter 22 indicating the number of occurrences of effective edges from missing teeth in the NE10 signal, and the interval between occurrences of effective edges in the NE10 signal are divided by a preset multiplication number (32 multiplications in this embodiment). And a multiplier circuit 23 for generating a multiplied clock signal with one period as one cycle. However, the crank processing unit 20 includes various logic circuits. The table counter 21 includes an upper counter 21a indicating the upper rotation angle of the crankshaft 9 and a lower counter 21b indicating the lower position.

  The microcomputer 2 includes a CPU 24 that executes various processes for controlling the engine, a ROM 25 that stores programs for various processes to be executed by the CPU 24 and data used for the various processes, and various data calculated by the various processes. Are temporarily stored, and an EEPROM 27, which is a non-volatile memory for storing a history of errors occurring in the engine ECU 1, and the like.

  Further, the microcomputer 2 compares the count value of the table counter 21 with various setting values set in advance for performing fuel injection control, ignition timing control, etc., and the count value of the table counter 21 matches these various setting values. When this occurs, the comparator 28 that generates an angle synchronization signal for the output circuit 7 and an interrupt signal for the CPU 24, and an internal clock signal with a period sufficiently shorter than the minimum time of the valid edge generation interval in the NE10 signal are always counted. And a free-run timer 29 to be uploaded.

  Further, the microcomputer 2 converts the signal of the air flow meter 16, the signal of the throttle sensor 17, and the signal of the water temperature sensor 18 input via the input circuit 6 into digital signals, and inputs the A / D converter 30 to the CPU 24. The starter switch 14 signal and the idle switch 15 signal input via the input circuit 5 are input to the CPU 24, while the output signal from the CPU 24 and the angle synchronization signal from the comparator 28 are output to the output circuit 7. And an I / O port 31 to be provided.

  In the microcomputer 2 configured as described above, the CPU 24 performs fuel injection control, ignition timing control, and the like, as well as a well-known engine ECU CPU, and the number of revolutions of the crankshaft 9 per unit time from the start of the engine. Until the specified rotation speed (500 rpm in the present embodiment) reaches a predetermined value, interrupt processing due to the effective edge of the NE10 signal is used to detect missing teeth and cylinders based on the NE10 signal and the G signal. Detection and measurement of the rotation angle of the crankshaft 9 are performed. Then, after the number of rotations of the crankshaft 9 reaches the designated number of rotations, if the missing teeth are further detected a predetermined number of times (in this embodiment, twice), measurement of the rotation angle of the crankshaft 9 by the crank processing unit 20 is enabled. This interrupt processing is stopped. Note that such interrupt processing of the CPU 24 is substantially the same as the contents described in the above-mentioned Patent Document 1, and therefore further description thereof is omitted here.

Hereinafter, various processes performed by the crank processing unit 20 will be described.
First, FIG. 2 is a flowchart showing the flow of the rotation angle measurement process performed by the crank processing unit 20. This process is executed every time a valid edge of a pulse in the NE10 signal occurs.

  As shown in FIG. 2, in this process, first, the timer value of the free-run timer 29 is reset to 0, and the timer value immediately before the reset is set as the current effective edge generation interval T (n). The storage area is set in the unit 20 (S100).

Then, in the storage area, it is confirmed whether or not the carry permission flag Fc that permits carry from the lower counter 21b to the upper counter 21a is set to ON (S105).
Here, when the carry permission flag Fc is set to OFF (No: S105), the count set in the storage area for temporarily storing the count value to be set this time as the count value MCntH of the upper counter 21a. A count value obtained by adding 1 to MCntH is set to the value tMCntH, and the count value MCntL of the lower counter 21b is reset to 0 (S110).

  Then, it is confirmed whether or not tMCntH is 33 or 69 (that is, a count value corresponding to the start time of missing teeth) (S115). If it is neither 33 nor 69 (No: S115), the carry permission flag Fc = The count value MCntM set in the storage area for storing MCntH at the time of ON is reset to 0 (S120), and the process proceeds to S155 described later.

  On the other hand, if tMCntH is 33 or 69 (Yes: S115), the temporary permission flag tFc set in the storage area is set ON to temporarily store the state of the carry permission flag Fc to be set this time (S125). ), The value of tMCntH is set to MCntM (S130), and the process proceeds to S155 described later.

  On the other hand, if the carry permission flag Fc is set to ON in S105 (Yes: S105), the temporary permission flag tFc is set to OFF (S135) and it is confirmed whether MCntM is 33 or 69. (S140).

  If MCntM is 33 (MCntM = 33: S140), tMCntH is set to 36, MCntL is reset to 0 (S145), and the process proceeds to S155 described later. On the other hand, if MCntM is 69 (MCntM = 69: S140), both tMCntH and MCntL are reset to 0 (S150).

  Then, T (n) / T (n−1), which is a ratio between the current effective edge generation interval T (n) set in the storage area and the previous effective edge generation interval T (n−1). ) Is calculated, and it is determined whether or not the calculated ratio is equal to or higher than a predetermined determination ratio K (in this embodiment, K = 2.4) preset in order to detect missing teeth (S155).

  Here, when the missing tooth determination condition that the calculated ratio is equal to or higher than the determination ratio K is not satisfied (No: S155), it is assumed that the missing tooth is not detected, and the count value SCnt of the back counter 22 is detected. A count value obtained by adding 1 to SCnt is set to the count value tSCnt set in the storage area in order to temporarily store the count value to be set this time (S160), and the process proceeds to S200 described later.

On the other hand, if the missing tooth determination condition is satisfied (Yes: S155), tSCnt is reset to 0 assuming that a missing tooth is detected (S165).
Then, it is confirmed whether or not tMCntH is 33 or 37 (S170). Here, the value 33 is obtained when one pulse that should have been generated is lost in the NE10 signal while the crankshaft 9 rotates from 0 ° to 360 ° (0 ° CA to 360 ° CA). TMCntH is a value that can be taken at the original missing tooth detection timing. The value of 37 is a value that tMCntH can take at the original missing tooth detection timing when one noise is generated in the NE10 signal while the crankshaft 9 rotates from 0 ° to 360 °. .

  If tMCntH is 33 or 37 (Yes: S170), tMCntH is set to 36, MCntL is reset to 0 (S175), and the process proceeds to S195 described later. The value of 36 is an original value that MCntH should originally take at the original missing tooth detection timing.

  On the other hand, if tMCntH is neither 33 nor 37 (No: S170), it is confirmed whether tMCntH is 69 or 1 (S180). Note that the value 69 here is when one pulse that should have occurred in the NE10 signal is missing while the crankshaft 9 rotates 360 ° to 720 ° (360 ° CA to 720 ° CA). TMCntH is a value that can be taken at the original missing tooth detection timing. A value of 1 is a value that tMCntH can take at the original missing tooth detection timing when one noise occurs in the NE10 signal while the crankshaft 9 rotates 360 ° to 720 °. .

If tMCntH is neither 69 nor 1 (No: S180), the process immediately proceeds to S200 described later.
On the other hand, if tMCntH is 69 or 1 (Yes: S180), both tMCntH and MCntL are reset to 0 (S185), and the temporary permission flag tFc is set to OFF (S195). The value of 0 is the original value of MCntH at the original missing tooth detection timing.

  Then, the values of tMCntH, tSCnt, and temporary permission flag tFc are set in MCntH, SCnt, and carry permission flag Fc, respectively (S200), and this process ends.

  Next, FIG. 3 is a flowchart showing the flow of the low-order counter process performed by the crank processing unit 20. This process is executed each time a valid edge (rising edge in the present embodiment) of the multiplied clock signal occurs.

  As shown in FIG. 3, in this process, first, it is confirmed whether or not MCntL is less than the maximum value (MAX) (S300). If it is less than the maximum value (Yes: S300), it is added to MCntL. The count value obtained by adding the value n is set to MCntL (S305), and this process ends. In the present embodiment, MCntL consists of 8 bits, and the added value n is set to 256/32 = 8. The maximum value is set to 31 × n = 248.

  On the other hand, if MCntL has reached the maximum value in S300 (No: S300), it is confirmed whether the carry permission flag Fc is set to ON (S310), and the carry permission flag Fc is turned OFF. If it is set (No: S310), this process is immediately terminated.

  On the other hand, when the carry permission flag Fc is set to ON (Yes: S310), MCntH is a value obtained by adding the number of missing pulses in the missing tooth section in the NE10 signal (that is, two) to MCntM. It is confirmed whether it is less than (S315).

  Here, if MCntH has reached MCntM + 2 (No: S315), this process is immediately terminated. On the other hand, if it is less than MCntM + 2 (Yes: S315), a value obtained by adding 1 to MCntH is set to MCntH. At the same time, MCntL is reset to 0 (S320), and this process is terminated.

  In the engine ECU 1 of the present embodiment configured as described above, as shown in FIG. 4, after the engine is started, until the number of revolutions of the crankshaft 9 per unit time reaches a designated number of revolutions, the CPU 24 By the process of, missing tooth detection, cylinder detection, measurement of the rotation angle of the crankshaft 9 and the like are executed. Then, when the missing tooth is further detected twice after the rotational speed of the crankshaft 9 reaches the designated rotational speed, the missing tooth detection by the crank processing unit 20 and the measurement of the rotational angle of the crankshaft 9 are made effective. FIG. 4 is a timing chart showing the processing timing of the engine ECU 1 when the engine is started. However, in FIG. 4, only the valid edge is shown for the NE10 signal in order to simplify the drawing.

  Then, as shown in FIG. 5, the crank processing unit 20 counts up both the count value MCntH of the upper counter 21a and the count value SCnt of the back counter 22 at the valid edge of the NE10 signal. On the other hand, the count value MCntL of the lower counter 21b is counted up at the valid edge of the multiplied clock signal (not shown), and MCntL is reset to 0 at the valid edge of the NE10 signal.

  In this way, the count value of each counter is counted up, and when the count value MCntH of the upper counter 21a reaches a value corresponding to the start point of missing teeth (that is, 33, 69), the carry permission flag Fc is turned ON. The count value MCntL of the lower counter 21b is wrapped round by the number of missing pulses in the missing tooth section, and the carry from the lower counter 21b to the upper counter 21a is performed.

  At the missing tooth detection timing, the carry permission flag Fc is set to OFF, and the count value SCnt of the back counter 22 is reset to zero. If the count value MCntH of the upper counter 21a has reached 71, it is reset to 0.

  Here, the operation of the crank processing unit 20 when noise or one missing pulse that should have occurred in the NE10 signal occurs in the section surrounded by the broken line frame in FIG. 5 will be described.

  First, as shown in FIG. 6, when one noise is generated in the NE10 signal at the timing satisfying the missing tooth determination condition in the section where the count value MCntH of the upper counter 21a should be counted up from 25 to 26 originally ( In the broken line frame A in the figure), the crank processing unit 20 erroneously detects missing teeth.

  Here, although the crank processing unit 20 resets the count value SCnt of the back counter 22 to 0, the value of tMCntH (that is, 28) at this timing is the absence of noise or a pulse that should have occurred in the NE10 signal. When one occurs, it differs from the value that tMCntH can take at the original missing tooth detection timing (that is, 33, 37, 69, 1), so at this timing, MCntH is not corrected to the original value. 28 (inside the broken line frame B in the figure).

When the count value MCntH of the upper counter 21a reaches the count value corresponding to the start point of missing teeth (that is, 33), the carry permission flag Fc is turned ON.
Here, due to the noise described above, the count value MCntH of the upper counter 21a has reached 33 before the start time of the original missing tooth, so that the carry permission flag Fc is ON. A valid edge occurs.

  Here, the crank processing unit 20 immediately turns off the carry permission flag Fc and sets MCntH to 36. This is because MCntH has reached 33 before the start of the original missing tooth due to the noise described above, and the carry from the lower counter 21b to the higher counter 21a is not performed in the original missing tooth section. In addition, this is a measure for preventing an error from occurring in MCntH.

  When the missing tooth is detected again (that is, when the original missing tooth is detected), tMCntH becomes 37 at this detection timing, and when one noise is generated in the NE10 signal, the original missing tooth detection timing is obtained. Since tMCntH matches a possible value, at this timing, the count value MCntH of the upper counter 21a is corrected to 36, which is the original value (in the broken line frame C in the figure).

  Next, as shown in FIG. 7, when one noise is generated in the NE10 signal at the timing not satisfying the missing tooth determination condition in the same section as in FIG. Similarly, tMCntH becomes 37 at the original missing tooth detection timing, and when one noise occurs in the NE10 signal, it matches the value that tMCntH can take at the original missing tooth detection timing. At this timing, the processing unit 20 corrects the count value MCntH of the upper counter 21a to 36, which is the original value.

  Next, as shown in FIG. 8, if one pulse that should have occurred is missing in the section in which the count value MCntH of the upper counter 21a should be counted up from 24 → 25 → 26 (the broken line in the figure). In the frame), tMCntH becomes 33 at the original missing tooth detection timing.

  Since this value matches the value that tMCntH can take at the original missing tooth detection timing when one pulse that should have occurred in the NE10 signal is missing, the crank processing unit 20 determines this timing. Thus, the count value MCntH of the upper counter 21a is corrected to 36, which is the original value. 5 to 8 are timing charts showing an example of the operation of the crank processing unit 20, respectively.

  As described above, in the engine ECU 1 of the present embodiment, at the timing at which the count value of the table counter 21 causes a large error, the NE10 signal lacks one noise or one pulse that should have occurred, Even if a missing tooth is erroneously detected, the count value of the table counter 21 is not corrected to an incorrect original value.

  That is, according to the engine ECU 1 of the present embodiment, the table counter 21 is used only when the value of tMCntH is a value that can be taken when noise or one missing pulse that should have occurred originally occurs in the NE10 signal. However, it is possible to prevent a large error from occurring in the count value indicating the rotation angle of the crankshaft 9 due to erroneous detection of missing teeth.

  Further, in the engine ECU 1 of the present embodiment, the rotation angle of the crankshaft 9 can be measured by the multiplied clock signal and the lower counter 21b, and the crankshaft 9 can be measured at the effective edge generation interval of the NE10 signal, and the crankshaft 9 can be determined by the count value MCntH of the upper counter 21a. The rotation angle of the crankshaft 9 can be shown more finely (in other words, the measurement resolution can be improved) by indicating the rotation angle of the crankshaft 9 with the count value MCntL of the lower counter 21b. .)

  Further, in the engine ECU 1 of the present embodiment, the count value MCntH of the upper counter 21a is counted up by a carry from the lower counter 21b in the missing tooth section, so even if the NE10 signal pulse is lost due to missing teeth, The rotation angle of the crankshaft 9 can be measured.

  Further, in the engine ECU 1 of the present embodiment, missing teeth are detected by complicated processing by software when the engine is started, so that missing teeth can be detected quickly when the engine is started without increasing the scale of the engine ECU 1. .

  In addition, since the engine rotation is stable and the effective edge generation interval in the NE10 signal falls within a certain range, the missing teeth are detected using a certain determination ratio, so the crank processing unit 20 is simply realized. it can. Furthermore, since the missing teeth are easily detected by the crank processing unit 20, the processing load on the CPU 24 is not increased.

  In this embodiment, the rotation angle measurement processing S110, 200 performed by the crank processing unit 20 and the upper counter 21a correspond to the first counter in the present invention, and the free-run timer 29, the rotation angle measurement, and the like. The process S100 corresponds to the generation interval measuring means in the present invention, and S155 corresponds to the second missing tooth detecting means in the present invention.

In this embodiment, S175, 185, and 200 of the rotation angle measurement process correspond to the correction unit in the present invention, and S170 and 180 correspond to the correction operation unit in the present invention.
In this embodiment, the rotation angle measurement processing S160, 165, and 200 and the back counter 22 correspond to the second counter in the present invention, and the multiplication circuit 23 corresponds to the multiplication clock generation means in the present invention. Further, S110 of the rotation angle measurement process, S300 and 305 of the lower counter process, and the lower counter 21b correspond to the third counter in the present invention.

  In this embodiment, S115 and 125 of the rotation angle measurement process and S310 and 315 of the lower counter process correspond to the carry-up permission means in the present invention, and the missing tooth detection performed by the CPU 24 is the first in the present invention. This corresponds to one missing tooth detection means, and the CPU 24 corresponds to the switching means in the present invention.

  By the way, in the engine ECU 1 of the present embodiment, as described above, it is premised that one or more missing pulses (that is, one count of the upper counter 21a) occur in the NE10 signal. However, the number of noises or missing pulses that should have occurred originally may be within two or three.

  More specifically, when noise and pulse loss are within two, it is determined whether or not tMCntH is 32, 33 or 37, 38 in S170 of the rotation angle measurement process. In this case, the crank processing unit 20 may be configured to determine whether tMCntH is 68, 69, or 1,2.

  Further, when the number of missing noises and pulses is within three, it is determined whether or not tMCntH is 31 to 33 or 37 to 39 in S170 of the rotation angle measurement process. Further, in S180, tMCntH is determined as tMCntH. What is necessary is just to comprise the crank process part 20 so that it may determine whether it is 67-69 or 1-3.

Also, for example, the number may be different from each other, such as one noise and less than two missing pulses.
However, as described above, for example, assuming two noises or missing pulses, false detection of missing teeth occurs in the missing tooth section and immediately after the missing tooth section, as shown in FIG. When one noise is generated at such timing, tMCntH becomes 38 at the erroneous detection timing of missing teeth immediately after the end of the missing tooth section, and the count value MCntH of the upper counter 21a is corrected to 36.

  In other words, even though only one noise is generated, when two noises are generated, the value coincides with the value 38 that tMCntH can take at the original missing tooth detection timing. In spite of the necessity, a new error −1 is generated. FIG. 9 is a timing chart showing an example of a problem when the engine ECU 1 of the present embodiment is based on the premise of missing two noises and pulses.

Therefore, next, even when there are two or more missing noises or pulses that should have occurred in the NE10 signal, the count value MCntH of the upper counter 21a can be corrected without causing the above-mentioned problem. A second embodiment will be described.
[Second Embodiment]
First, the engine ECU 1 of the present embodiment merely configures the crank processing unit 20 so as to execute a newly added process during the rotation angle measurement process of the first embodiment.

Accordingly, here, the same steps as those of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. Only the newly added steps of the processing will be described.
Here, FIG. 10 is a flowchart showing the flow of the rotation angle measurement process performed by the crank processing unit 20 in the present embodiment.

  As shown in FIG. 10, in this process, if tMCntH is neither 69 nor 1 in the above-described S180 (No: S180), the newly added process is executed (S190), and then through the above-described S200. This process is terminated.

Next, FIG. 11 is a flowchart showing the flow of the addition process (S190).
As shown in FIG. 11, in this process, first, in the storage area, the error flag Fe indicating that tMCntH was not 33, 37, 69, or 1 at the previous missing tooth detection timing is set to ON. It is confirmed whether it has been done (S400).

  Here, when the error flag Fe is set to OFF (No: S400), the error flag Fe is set to ON (S405), and the tMCntH at this time is set in the storage area. This tMCntH is set to the counted value MCntE (S410), and this process is terminated.

  On the other hand, if the error flag Fe is set to ON (Yes: S400), the absolute value of the difference between tMCntH and MCntE set in the storage area is calculated, and this calculation result is the missing tooth occurrence interval. It is determined whether or not the corresponding value is 36 (S415).

  Here, when the difference is other than 36 (No: S415), the process proceeds to the above-described S410. When the difference is 36 (Yes: S415), it is determined whether tMCntH is 17 or more and less than 53. Determination is made (S420). Here, the range of 17 ≦ tMCntH <53 is a range centering on tMCntH = 36. By determining whether or not tMCntH is within this range, the missing tooth detection timing is actually tMCntH. It is determined whether it corresponds to = 36 or tMCntH = 0.

  If tMCntH is less than 17 or greater than 53 (No: S420), tMCntH and tMCntL are reset to 0 (S425), assuming that the missing tooth detection timing corresponds to tMCntH = 0 (S425). The process proceeds to S435.

  On the other hand, when tMCntH is 17 or more and less than 53 (Yes: S420), it is assumed that the missing tooth detection timing corresponds to tMCntH = 36, and 36 is set to tMCntH and MCntL is reset to 0 ( (S430), the error flag Fe is set to OFF (S435), and this process ends.

  As shown in FIG. 12, the crank processing unit 20 of the present embodiment configured in this way, when two noises occur in the NE10 signal at a timing that does not satisfy the missing tooth determination condition, at the missing tooth detection timing. Since tMCntH = 38, which is neither 33, 37, 69, nor 1, the count value MCntH of the upper counter 21a is set to 38 without being corrected to the original value of 36.

  If there is no new noise or missing pulse until the next missing tooth detection timing, the difference between tMCntH (MCntE) at the current missing tooth detection timing and tMCntH at the next missing tooth detection timing is Since this corresponds to the missing tooth occurrence interval, MCntH is corrected to the original value of 0 at the next missing tooth detection timing.

  Further, as shown in FIG. 13, the crank processing unit 20 detects the missing tooth detection timing when two missing pulses are missing in the NE10 signal so as not to satisfy the missing tooth determination condition. TMCntH = 32, which is neither 33, 37, 69, nor 1, so the count value MCntH of the upper counter 21a is set to 32 without being corrected to the original value of 36.

  If there is no new noise or missing pulse until the next missing tooth detection timing, the difference between tMCntH (MCntE) at the current missing tooth detection timing and tMCntH at the next missing tooth detection timing is Since this corresponds to the missing tooth occurrence interval, MCntH is corrected to the original value of 0 at the next missing tooth detection timing.

  However, as shown in FIG. 14, when two noises are generated in the NE10 signal at a timing at which the missing tooth determination condition is not satisfied, the crank processing unit 20 sets the count value MCntH of the upper counter 21a to the original value as described above. However, if one new noise is generated so as not to satisfy the missing tooth detection condition by the next missing tooth detection timing, the current missing tooth is corrected. Since the difference between tMCntH (MCntE) at the detection timing of tMCntH and tMCntH at the detection timing of the next missing tooth is different from the missing tooth occurrence interval, the count value MCntH of the upper counter 21a is also detected at the next missing tooth detection timing. Is not corrected to the original value of 0.

  However, if no new missing noise or pulse occurs at the subsequent missing tooth detection timing, the difference between tMCntE and tMCntH corresponds to the missing tooth generation interval at the subsequent missing tooth detection timing. Therefore, at that time, the count value MCntH of the upper counter 21a is corrected to the original value. 12 to 14 are timing charts showing an example of the operation of the crank processing unit 20 in the present embodiment.

  That is, if the current missing tooth detection timing or the previous missing tooth detection timing is caused by the erroneous detection of missing teeth, tMCntH at the current missing tooth detection timing and the previous missing tooth detection timing. The difference from tMCntH becomes unequal to the count value corresponding to the missing tooth occurrence interval. On the other hand, if the current missing tooth detection timing and the previous missing tooth detection timing are caused by the original missing tooth detection, and if no new noise or missing pulse has occurred during that time, two NE10 signals are included. Even when the above-mentioned noise or missing pulse occurs, the difference between tMCnt at the present missing tooth detection timing and tMCntH at the previous missing tooth detection timing is equal to the missing tooth occurrence interval.

  Therefore, according to the engine ECU 1 of the present embodiment, even if two or more noises or missing pulses occur, the count value MCntH of the upper counter 21a can be corrected to the original value at the original missing tooth detection timing.

  In addition, even if new missing teeth or missing pulses occur even though the detection timing of this missing tooth and the previous missing tooth detection timing are due to the original missing tooth detection, If no new noise or missing pulse occurs after the next missing tooth timing, the count value MCntH of the upper counter 21a can be corrected to the original value after the next missing tooth detection timing.

  In this embodiment, S400 and 415 of the additional processing performed by the crank processing unit 20 correspond to the correction execution means described in claim 2 in the present invention, and S420 to S430 and S200 of the rotation angle measurement processing are the first in the present invention. This corresponds to 2 setting means.

  By the way, in this embodiment, the crank processing unit 20 has corrected tMCntH to the nearest original value in S420 to 430, but may be configured to set the original value according to the logical level of the G signal. good.

  That is, as described above, the logical level of the G signal is low when the rotation angle of the crankshaft 9 is 360 ° CA, and is high when 720 ° CA (0 ° CA). By determining the logical level, a correct original value can be set.

Therefore, the crank processing unit 20 is configured to determine the logical level of the G signal in S420 of the above-described additional processing, and shift to S425 if it is high and shift to S430 if it is low. It ’s fine. In this case, S420, 425, and 430 correspond to the level discriminating means and the first setting means in the present invention.
[Third Embodiment]
Next, a third embodiment will be described. However, the engine ECU 1 of the present embodiment only realizes part of the processing performed by the crank processing unit 20 of the second embodiment by software processing of the CPU 24, and the parts other than those related to this are the second embodiment. Is exactly the same. Therefore, description of parts common to the second embodiment will be omitted here, and only different parts will be described.

  First, in the engine ECU 1 of the present embodiment, the crank processing unit 20 is configured to only count up and detect missing teeth of the front counter 21 and the back counter 22, and the CPU 24 performs the valid edge ( In the present embodiment, in synchronization with the rising edge), both the count values of the front counter 21 and the back counter 22 are read, and the count value of the front counter 21 can be corrected (not shown). The CPU 24 is set to perform the following abnormality determination process in addition to the above-described various software processes.

Here, FIG. 15 is a flowchart showing the flow of the abnormality determination process performed by the CPU 24. This process is repeatedly executed at regular intervals.
As shown in FIG. 15, in this process, first, the count value MCntH of the upper counter 21a is obtained and set in the RAM 26 as the count value CntM1 (S500). Subsequently, the count value SCnt of the back counter 22 is acquired and set in the RAM 26 as the count value CntS (S505). Then, the count value MCntH of the upper counter 21a is acquired again and set in the RAM 26 as a count value CntM2 different from the count value CntM1 (S510), and it is confirmed whether CntM1 and CntM2 match (S510). S515).

  Here, when CntM1 and CntM2 do not match (No: S515), the processes of S500 to S515 are repeated until they match, while when CntM1 and CntM2 match (Yes: S515). Then, it is determined whether CntM1 and CntS are consistent (S520). Here, when CntM1 and CntS match or when the absolute value of the difference between them is 36, it is determined that they are matched, and in other cases, they are determined to be mismatched. To do.

  If it is determined that CntM1 and CntS are consistent (Yes: S520), the process is immediately terminated. On the other hand, if it is determined that there is a mismatch (No: S520), the mismatch is not detected. The occurrence is set in the EEPROM 27 as an error history (S525).

  Subsequently, it is confirmed whether or not CntS is 0 (that is, whether or not the crank processing unit 20 has detected a missing tooth) (S530). If it is not 0 (No: S530), this process is immediately performed. finish.

On the other hand, when CntS is 0 (Yes: S530), after performing the correction process which performs the correction | amendment similar to the crank process part 20 of 2nd Embodiment (S535), this process is complete | finished.
Here, FIG. 16 is a flowchart showing the flow of the above-described correction processing (S535).

  As shown in FIG. 16, in this process, first, it is confirmed whether CntM1 is 33 or 37 (S600). If CntM1 is 33 or 37 (Yes: S600), the process proceeds to S635 described later. On the other hand, if it is not 33 or 37 (No: S600), it is checked whether CntM1 is 69 or 1 (S605).

  If CntM1 is 69 or 1 (Yes: S605), the process immediately proceeds to S640 described later, whereas if it is neither 69 nor 1 (No: S605), the error flag Fe is turned ON in the RAM 26. It is confirmed whether it is set (S610).

  If the error flag Fe is set to OFF (No: S610), the error flag Fe is set to ON (S615), and then CntM1 is set to CntE (corresponding to MCntE in the second embodiment). (S620), and this process ends.

  On the other hand, when the error flag Fe is set to ON (Yes: S610), the absolute value of the difference between CntM1 and CntE is calculated, and it is determined whether or not the calculation result is 36 (S625). .

  Here, when the difference is other than 36 (No: S625), the process proceeds to the above-described S620, while when the difference is 36 (Yes: S625), whether CntM1 is 17 or more and less than 53. Is determined (S630).

  If CntM1 is 17 or more and less than 53 (Yes: S630), assuming that the missing tooth detection timing corresponds to MCntH = 36, 36 is set in MCntH (S635), and the process proceeds to S645 described later. To do.

  On the other hand, when CntM1 is less than 17 or 53 or more (No: S630), it is assumed that the missing tooth detection timing corresponds to MCntH = 0, and MCntH is reset to 0 (S640), and then the error flag Fe is set. It is set to OFF (S645), and this process ends. In S635 and 640, the CPU 24 corrects only the count value MCntH of the upper counter 21a and does not correct the count value MCntL of the lower counter 21b. The crank processor 20 is at the effective edge of the NE10 signal. This is because MCntL is reset to 0, and the CPU 24 does not have to do this purposely.

  In the engine ECU 1 of the present embodiment configured as described above, the CPU 24 performs the correction process only when the count value MCntH of the upper counter 21a and the count value SCnt of the back counter 22 are inconsistent. Even when erroneous detection occurs, it is possible to prevent the count value MCntH of the upper counter 21a from being corrected to an incorrect value.

  Further, in the engine ECU 1 of the present embodiment, part of the processing performed by the crank processing unit 20 of the second embodiment is performed by software processing of the CPU 24, so that the configuration of the crank processing unit 20 can be simplified correspondingly. As a result, the configuration of the engine ECU 1 itself can be simplified.

  Further, in the engine ECU 1 of the present embodiment, the CPU 24 acquires the count value MCntH of the upper counter 21a and the count value SCnt of the back counter 22 in order rather than simultaneously, and therefore there is a deviation in the acquisition timing.

  However, as indicated by the black dots in FIGS. 17A, 17B, 18A, and 18B, the CPU 24 alternately acquires MCntH and SCnt, and MCntH acquired twice coincides with each other. In order to determine whether or not MCntH and SCnt are consistent, it is determined that the MCntH and SCnt are inconsistent even though they are actually matched. It can be prevented from being determined to be consistent. FIG. 17 is an explanatory diagram showing an example of the acquisition timing when the count value MCntH of the upper counter 21a and the count value SCnt of the back counter 22 match. FIG. 18 is an explanatory diagram showing an example of acquisition timing when the count value MCntH of the upper counter 21a and the count value SCnt of the back counter 22 are inconsistent.

  Further, in the engine ECU 1 of the present embodiment, as shown by the black dots in FIGS. 17C, 17D, 18C, and 18D, the CPU 24 receives the NE10 signal while acquiring two MCntHs. If the obtained MCntHs do not coincide with each other, and the acquisition of MCntH and SCnt is repeated until the MCntHs coincide with each other, it is possible to reliably determine whether MCntH and SCnt match.

In this embodiment, S635 and 640 of the correction process correspond to the correction unit in the present invention, and S600, 605, 610, and 625 correspond to the correction operation unit in the present invention.
In the present embodiment, the correction processing S630, 635, 640 corresponds to the second setting means in the present invention, and the abnormality determination processing S500, 505, 510 corresponds to the count value acquisition means in the present invention.

In this embodiment, S515 and 520 of the abnormality determination process correspond to the correction permission means in the present invention, and S515 corresponds to the reactivation means in the present invention.
In the present embodiment, the CPU 24 is set to perform the correction process when the count value SCnt of the back counter 22 is 0 (that is, the missing tooth detection timing). It may be set to perform the correction process when it has reached.

  In other words, the count value SCnt of the back counter 22 is reset to 0 even when a missing tooth is erroneously detected. Therefore, if the designated count value is appropriately set, until the missing tooth is detected erroneously until the original missing tooth is detected. The count value SCnt of the back counter 22 does not reach the specified count value, and the count value MCntH of the upper counter 21a should be taken at the original missing tooth detection timing only at the timing caused by the original missing tooth detection. It can be corrected to the original value. Thereby, the processing load of the CPU 24 can be reduced.

  In this embodiment, the CPU 24 reads the count value MCntH of the upper counter 21a twice in S500 to S515 of the correction process and determines whether or not they match each other. Thus, the count value SCnt of the back counter 22 may be read twice, and it may be set so as to determine whether or not they match each other.

In the present embodiment, the error history is performed in S525, but instead of this, it may be set to execute a fail-safe process for driving the vehicle safely.
In this embodiment, after correcting the count value MCntH of the upper counter 21a, the CPU 24 determines again whether MCntH and SCnt are matched and confirms that the correction is correct. May be.

In the present embodiment, the CPU 24 may be set so that the crank processing unit 20 performs correction at the timing when the count value MCntH of the upper counter 21a changes.
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and it goes without saying that various forms can be taken as long as they belong to the technical scope of the present invention. .

  For example, in any of the above embodiments, the rising edge of the NE10 signal is the effective edge, but the falling edge may be the effective edge, or both the rising edge and the falling edge may be the effective edge. When both are effective edges, the rotation angle of the crankshaft 9 can be measured more finely (that is, the measurement resolution can be improved).

  In any of the above embodiments, the count value MCntH of the upper counter 21a is set to 0 or 36 at the missing tooth detection timing, but a value other than 0 or 36 (for example, 15 or 51) is set. Also good. In this case, a process of setting a guard value (MCntH = 72 → 0) may be added in the process of adding 1 to MCntH.

  In any of the above-described embodiments, the present invention is applied to an engine ECU that controls a four-cycle in-line four-cylinder engine. However, the present invention may of course be applied to an engine ECU that controls another form of engine. .

  In any of the above embodiments, the rotor 10 is provided with only one missing tooth portion 102, but a plurality of rotor teeth may be provided. In a plurality of cases, the missing teeth 102 may be provided continuously.

  In any of the above-described embodiments, the teeth 101 of the rotor 10 are formed at intervals of 10 ° CA. However, the teeth 101 may of course be formed at intervals of other rotation angles (for example, 6 ° CA). good.

1 is a configuration block diagram showing a configuration of an engine ECU 1 in a first embodiment. It is a flowchart which shows the flow of the rotation angle measurement process which the crank process part 20 in 1st Embodiment performs. It is a flowchart which shows the flow of the low-order counter process which the crank process part 20 in 1st Embodiment performs. It is a flowchart which shows the timing of the process of engine ECU1 of 1st Embodiment at the time of engine starting. It is a timing chart which shows an example of operation | movement of the crank process part 20 in 1st Embodiment. It is a timing chart which shows an example of operation | movement of the crank process part 20 in 1st Embodiment. It is a timing chart which shows an example of operation | movement of the crank process part 20 in 1st Embodiment. It is a timing chart which shows an example of operation | movement of the crank process part 20 in 1st Embodiment. 3 is a timing chart showing an example of a problem when two noises and missing pulses are assumed in the engine ECU 1 of the first embodiment. It is a flowchart which shows the flow of the rotation angle measurement process which the crank process part 20 in 2nd Embodiment performs. It is a flowchart which shows the flow of the additional process which the crank process part 20 in 2nd Embodiment performs. It is a timing chart which shows an example of operation of crank processing part 20 in a 2nd embodiment. It is a timing chart which shows an example of operation of crank processing part 20 in a 2nd embodiment. It is a timing chart which shows an example of operation of crank processing part 20 in a 2nd embodiment. It is a flowchart which shows the flow of the abnormality determination process which CPU24 in 3rd Embodiment performs. It is a flowchart which shows the flow of the correction process which CPU24 in 3rd Embodiment performs. It is explanatory drawing which shows an example of the acquisition timing in case count value MCntH of the high-order counter 21a and count value SCnt of the back counter 22 are in agreement. It is explanatory drawing which shows an example of the acquisition timing in case count value MCntH of the high-order counter 21a and count value SCnt of the back counter 22 are inconsistent. It is explanatory drawing which shows an example of the shift | offset | difference of an acquisition timing. It is a timing chart which shows an example at the time of noise superimposing on a crankshaft signal at the timing which a missing tooth determination condition is satisfied. It is a timing chart which shows an example when the output fall of the crankshaft rotation signal that the missing tooth determination condition is satisfied occurs.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Engine ECU, 2 ... Microcomputer, 3, 4, 5, 6 ... Input circuit, 7 ... Output circuit, 8 ... Crankshaft sensor, 9 ... Crankshaft, 10,13 ... Rotor, 11 ... Camshaft sensor, 12 ... Camshaft, 14 ... Starter switch, 15 ... Idle switch, 16 ... Air flow meter, 17 ... Throttle sensor, 18 ... Water temperature sensor, 19 ... Igniter, 20 ... Crank processor, 21 ... Table counter, 21a ... Upper counter, 21b ... Lower counter, 22 ... back counter, 23 ... multiplication circuit, 24 ... CPU, 25 ... ROM, 26 ... RAM, 27 ... EEPROM, 28 ... comparator, 29 ... free-run timer, 30 ... A / D converter, 31 ... I / O port, 41, 42, 43, 44 ... ignition coil, 51, 52, 53, 54 ... fuel injection valve, 101 ... tooth, 102 ... missing tooth part.

Claims (11)

An engine control device that sequentially measures the rotation angle of the crankshaft of an engine and controls the engine based on the measurement result,
When the rotational position of the crankshaft is other than a preset reference position, a pulse is generated each time the crankshaft rotates by a predetermined angle, and when the crankshaft is at the reference position, the crankshaft has an angle larger than the predetermined angle. A crankshaft rotation signal that causes a missing tooth missing the pulse until the rotation is input, the count value is counted up at the effective edge of the pulse in the crankshaft rotation signal, and the measurement result is indicated by the count value. 1 counter,
An occurrence interval measuring means for sequentially measuring the occurrence interval of the effective edge;
A ratio between the current measurement result of the generation interval measuring means and the previous measurement result is sequentially calculated, and is set in advance to determine whether or not the missing tooth has occurred between the calculated ratio and the effective edge. Missing tooth detection means for detecting the missing tooth based on the determination ratio;
Correction means for correcting the count value of the first counter to an original value, which is a value that the count value of the first counter should originally take at a correction timing based on the missing tooth detection timing of the missing tooth detection means; ,
In the correction timing, the count value of the first counter is a value that can be taken when a deviation within a designated number specified in advance occurs , and the count value of the first counter Even if it is a value that can be taken when a deviation exceeding the specified number occurs, the count value of the first counter at the current correction timing and the count value of the first counter at the previous correction timing When the difference is calculated, and the calculated difference is equal to the count value corresponding to the occurrence interval of the missing teeth, the correction operation means for operating the correction means,
An engine control device comprising: The engine control apparatus according to claim 1, wherein the deviation within the specified number is one occurrence of the effective edge. Level discriminating means for discriminating the level of a cylinder discriminating signal whose level changes according to the rotational position of the cam shaft of the engine;
First setting means for setting a value corresponding to a determination result of the level determination means to the original value among a plurality of types of the original values set in advance according to the level of the cylinder determination signal;
The engine control apparatus according to claim 1, further comprising: Of the plurality of kinds of original values preset in accordance with the correction timing, there is provided second setting means for setting a value closest to the count value of the first counter to the original value. The engine control device according to claim 1 or 2. An engine control device that sequentially measures the rotation angle of the crankshaft of an engine and controls the engine based on the measurement result,
When the rotational position of the crankshaft is other than a preset reference position, a pulse is generated each time the crankshaft rotates by a predetermined angle, and when the crankshaft is at the reference position, the crankshaft has an angle larger than the predetermined angle. A crankshaft rotation signal that causes a missing tooth missing the pulse until the rotation is input, the count value is counted up at the effective edge of the pulse in the crankshaft rotation signal, and the measurement result is indicated by the count value. 1 counter,
An occurrence interval measuring means for sequentially measuring the occurrence interval of the effective edge;
A ratio between the current measurement result of the generation interval measuring means and the previous measurement result is sequentially calculated, and is set in advance to determine whether or not the missing tooth has occurred between the calculated ratio and the effective edge. Missing tooth detection means for detecting the missing tooth based on the determination ratio;
Correction means for correcting the count value of the first counter to an original value, which is a value that the count value of the first counter should originally take at a correction timing based on the missing tooth detection timing of the missing tooth detection means; ,
Correction operation means for operating the correction means when the count value of the first counter is a value that can be taken when a deviation within a specified number specified in advance occurs at the correction timing;
A second counter that receives the crankshaft rotation signal, counts up the count value at the effective edge, and resets the count value to 0 at the missing tooth detection timing;
With
An engine control device characterized in that a timing at which the count value of the second counter reaches a designated count value other than 0 designated in advance is used as the correction timing. An engine control device that sequentially measures the rotation angle of the crankshaft of an engine and controls the engine based on the measurement result,
When the rotational position of the crankshaft is other than a preset reference position, a pulse is generated each time the crankshaft rotates by a predetermined angle, and when the crankshaft is at the reference position, the crankshaft has an angle larger than the predetermined angle. A crankshaft rotation signal that causes a missing tooth missing the pulse until the rotation is input, the count value is counted up at the effective edge of the pulse in the crankshaft rotation signal, and the measurement result is indicated by the count value. 1 counter,
An occurrence interval measuring means for sequentially measuring the occurrence interval of the effective edge;
A ratio between the current measurement result of the generation interval measuring means and the previous measurement result is sequentially calculated, and is set in advance to determine whether or not the missing tooth has occurred between the calculated ratio and the effective edge. Missing tooth detection means for detecting the missing tooth based on the determination ratio;
Correction means for correcting the count value of the first counter to an original value, which is a value that the count value of the first counter should originally take at a correction timing based on the missing tooth detection timing of the missing tooth detection means; ,
Correction operation means for operating the correction means when the count value of the first counter is a value that can be taken when a deviation within a specified number specified in advance occurs at the correction timing;
A second counter that receives the crankshaft rotation signal, counts up the count value at the effective edge, and resets the count value to 0 at the missing tooth detection timing;
Count value acquisition means for acquiring the count value of the first counter and the count value of the second counter between the correction timings;
The count value of the first counter acquired by the count value acquisition means is compared with the count value of the second counter, and the operation of the correction operation means is performed only when these count values are inconsistent. Amendment permitting means to permit
With
The count value acquisition unit alternately acquires at least three count values of the first counter and a count value of the second counter at a time interval shorter than a minimum time of occurrence intervals of the valid edges. And
The correction permission means is only when the count values of one counter that has acquired a plurality of count values of the count value of the first counter and the count value of the second counter match each other. An engine control device that operates. When the count values of one counter that has acquired a plurality of count values out of the count values of the first counter acquired by the count value acquisition means and the count values of the second counter do not match. The engine control device according to claim 6, further comprising a reactivation means for reactivating the count value acquisition means. Even when the count value of the first counter is a value that can be taken when a deviation exceeding the specified number occurs, the correction actuating means is configured to obtain the count value of the first counter at the current correction timing. Calculating a difference from the count value of the first counter at the previous correction timing, and operating the correction means if the calculated difference is equal to a count value corresponding to the missing tooth occurrence interval. The engine control device according to any one of claims 5 to 7. A multiplied clock generating means for generating a multiplied clock signal having a period obtained by dividing the previous measurement result of the generation interval measuring means by a preset multiplication number;
A third counter that counts up the count value to the multiplication number by the multiplied clock signal and resets the count value to 0 at the effective edge;
The engine control device according to any one of claims 1 to 8, further comprising: The missing tooth detection means includes
First missing tooth detection means that is implemented using software and detects the missing teeth;
Second missing tooth detecting means for detecting the missing tooth based on the calculated ratio and a predetermined fixed determination ratio;
The first missing tooth detecting means is operated until the number of revolutions of the crankshaft per unit time reaches a designated designated number of revolutions, and after reaching the designated number of revolutions, the first missing piece is detected. Switching means for operating the second missing tooth detecting means instead of the tooth detecting means;
The engine control apparatus according to any one of claims 1 to 9, further comprising: The engine control apparatus according to claim 10, wherein the second missing tooth detection unit is realized using hardware.

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