JP2002242748A - Engine control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engine control device capable of attaining a decrease in processing load and accuracy improvement, and performing an appropriate engine control even when a crank signal has noises. SOLUTION: A reference counter 108 performs counting-up with a multiplication clock based on the count of a pulse interval of a crank signal, and a following counter 109 performs counting-up in such a range so as not to excess the count value of the reference counter 108 with an internal clock. If a CPU determines it as lacking at the right side at every 720 deg. CA of the crank signal, the count value of the reference counter 108 is set at a value corresponding to the lacking at the right side. If the CPU determines it as lacking at the back side, the counter value of the reference counter 108 is set at a value corresponding to the lacking at the back side. If the count value of the following counter 109 is larger than a prescribed value, the count value of the following counter 109 is set at a value corresponding to the lacking at the back side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine control device.

[0002]

2. Description of the Related Art An engine control device is a device for controlling fuel injection control, ignition timing control, idle speed control, and the like, and operates an engine in an optimum state. That is, signals from various sensors that detect the engine operating state, such as a crank sensor and an engine water temperature sensor, are transmitted as E.
Input to a CU (Electronic Control Unit) to control the optimal fuel injection amount, injection timing, ignition timing, etc.

Control synchronized with engine rotation such as ignition control and injection control, that is, control synchronized with crank angle, generates a signal such as an ignition pulse when an offset time from a crank edge (edge of a crank signal) elapses. Let's go.

[0004]

However, it is necessary to perform an operation for conversion from angle to time, and there is a demand to reduce processing load and improve accuracy.

SUMMARY OF THE INVENTION The present invention has been made in view of such a background, and has as its object to reduce the processing load and improve the accuracy and to properly control the engine even if noise is present in the crank signal. It is an object of the present invention to provide an engine control device that can perform the control.

[0006]

According to the first aspect of the present invention, three reference positions are provided in the middle of a pulse train at predetermined angular intervals corresponding to the rotation of the crankshaft of the four-cycle engine.
The pulse interval is measured by the pulse interval measuring means for the crank signal having every 60 ° CA, and the multiplied signal generating means sets the frequency of an integral multiple until the next pulse based on the current pulse interval by the pulse interval measuring means. Is generated. The reference counter counts with the multiplied signal, and the follow-up counter counts with an internal clock within a range not exceeding the count value of the reference counter. As described above, by generating a multiplied signal at a predetermined angular interval and synchronizing with the engine rotation, a calculation for converting from angle to time can be omitted, thereby reducing processing load and improving accuracy. Can be planned.

Further, a reference counter and a follow-up counter are initialized every 720 ° CA with reference to a reference position portion of a table for every 720 ° CA of the crank signal. On the other hand, when it is determined that the reference position is at the back reference position every 720 ° CA of the crank signal, the count value of the reference counter is set by the count value setting means to a value corresponding to the back reference position, and If the value exceeds a predetermined value, the count value of the tracking counter is set to a value corresponding to the back reference position. Therefore, the tracking counter operates within the range that does not exceed the count value of the reference counter, and noise is applied to the crank signal from the reference position on the front to the reference position on the back, and the reference position on the back is erroneously detected. In this case, the count value of the reference counter is set to a value corresponding to the back reference position, and the tracking counter performs a counting operation until the subsequent back reference position is properly detected. If the count value of the reference counter is set to a value corresponding to the reference position on the back when detection is performed, the tracking operation of the tracking counter will not be performed until the count value of the reference counter exceeds the count value of the tracking counter. Since the count value of the tracking counter exceeds a predetermined value when the back reference position is correctly detected after the position is erroneously detected, the counter DOO value is set to the value of the corresponding reference positions of the back, so that the counting operation of the tracking counter is started. In this way, when the reference position on the back side is determined based on the crank signal, even if noise is included in the crank signal and the reference position portion on the back side is erroneously detected, the tracking counter is operated in a normal state within 360 ° CA. be able to. As a result, even if noise is included in the crank signal, the engine control can be appropriately performed, and the engine control device is resistant to noise.

According to the second aspect of the present invention, a pulse signal corresponding to a crank signal having a reference position portion at every 360 ° CA in a pulse train at predetermined angular intervals corresponding to the rotation of the crankshaft of the four-cycle engine is provided. The pulse interval is measured by the interval measuring means, and the multiplied signal generating means generates a multiplied signal of an integral multiple frequency by the next pulse based on the current pulse interval by the pulse interval measuring means. The reference counter counts with the multiplied signal, and the follow-up counter counts with an internal clock within a range not exceeding the count value of the reference counter. As described above, by generating a multiplied signal at a predetermined angular interval and synchronizing with the engine rotation, a calculation for converting from angle to time can be omitted, thereby reducing processing load and improving accuracy. Can be planned.

Further, a reference counter and a follow-up counter are initialized at every 720 ° CA with reference to a reference position portion of a table for each 720 ° CA of the crank signal. On the other hand, when it is determined that the reference position is located at the back of each 720 ° CA of the crank signal, the count value of the follow-up counter or the count value of the counter that counts by the pulse of the crank signal by the count value setting means is within a predetermined range. Only when the value is within the range, the count value of at least one of the reference counter and the follow-up counter is set to a value corresponding to the back reference position. In other words, when it is determined that the reference position is located at the back of each 720 ° CA of the crank signal, the count value of the follow-up counter or the count value of the counter that counts by the pulse of the crank signal falls within a predetermined range. Otherwise, at least one of the count values of the reference counter and the follow-up counter is not set to a value corresponding to the reference position on the back. In other words, when noise is erroneously detected at the reference position portion behind the crank signal, the count value of the follow-up counter or the count value of the counter that counts with the pulse of the crank signal is not within the predetermined range, and the reference value is not within the predetermined range. At least one of the count value of the counter and the following counter is not set to a value corresponding to the reference position at the back. Therefore, when the reference position on the back side is determined based on the crank signal, the counter can be operated in a normal state even if noise is detected in the crank signal and the reference position portion on the back side is erroneously detected. as a result,
Even if the crank signal contains noise, the engine control can be properly performed, and the engine control device is resistant to noise.

Further, according to the invention described in claim 4,
When it is determined that the crank signal is at the reference position in the table for each 720 ° CA, the reference value is set only when the count value of the tracking counter or the count value of the counter that counts by the pulse of the crank signal is within a predetermined range. At least one of the count value of the counter and the following counter is set to a value corresponding to the reference position in the table. Therefore, even when noise is erroneously detected in the reference position of the riding table, the counter is not set to an erroneous reference position equivalent value, and the counter can be operated in a normal state.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment of the present invention will be described below with reference to the drawings.

The present embodiment is embodied in a control device for a multi-cylinder gasoline engine for an automobile. FIG. 1 shows a configuration of an engine control ECU 1 according to the present embodiment. The engine is a five-cylinder four-cycle engine.

The engine control ECU 1 includes a microcomputer (hereinafter referred to as a microcomputer) 10, a power supply circuit 20, an input / output circuit 30, and an EEPROM 40. The power supply circuit 20 receives power from the battery 2 and supplies a predetermined voltage to each device in the ECU 1. The microcomputer 10 is a CP
A U11, a ROM 12, a RAM 13, an A / D converter 14, an input / output interface 15, and a timer module 16 are provided. Data is exchanged between these members via a data bus. An EEPROM 40 is connected to the input / output interface 15, and data is exchanged with the EEPROM 40 via the input / output interface 15. The input / output circuit 30 inputs signals from sensors, switches, and the like, and outputs drive signals to injectors (fuel injection valves) and ignition devices. Further, the communication line 3 is connected to the input / output circuit 30, and data is exchanged with another ECU via the input / output circuit 30. The CPU 11 of the microcomputer 10 has a sensor
A signal (data) from a switch or the like and data from the communication line 3 are transmitted to the input / output circuit 30 and the input / output interface 1.
5, various calculations are performed based on the data, and the injectors and the like are driven and controlled via the input / output interface 15 and the input / output circuit 30.

Here, the signals received by the engine control ECU 1 include a crank signal from a crank sensor (crank signal generating means) and a cam sensor (cylinder discriminating signal generating means).
There is a cam signal from FIG. 2 shows a crank signal and a cam signal for one engine cycle (720 ° CA).

The crank signal generated by the crank sensor is composed of a pulse train at predetermined angular intervals corresponding to the rotation of the crankshaft of the four-stroke engine. The pulse train has a missing tooth (reference position) in the middle of the pulse train. . The crank signal in the present embodiment has a missing tooth configuration in which two pulses are missing every 60 pulses (60-2 tooth structure). In other words, the pulse interval of the pulse train is 6 ° CA, and a missing tooth from which a pulse is extracted is provided every 360 ° CA in the middle of this pulse train, and one of them (the missing tooth every 720 ° CA) is a front missing tooth. Yes, other (missing teeth every other 720 ° CA)
Are missing teeth. The cam signal generated by the cam sensor is synchronized with the rotation of the camshaft of the engine, is a cylinder discrimination signal for specifying the cylinder position, and has a falling edge at an interval of 144 ° CA. In this cam signal, the cam signal is at the L level at the falling edge (timing of t1) immediately after the missing tooth of the crank signal, and the cam signal is H at the falling edge immediately after the missing tooth (timing of t2).
Level. That is, if the cam signal level is L at the missing tooth position, it can be determined that the tooth is a front missing tooth, and if it is H, it can be determined that the tooth is a back missing tooth.

A crank signal is generated by the timer module 1 shown in FIG.
6 is input to the hard crank 100. The cam signal is taken into the microcomputer 10 via the input / output circuit 30. On the other hand, the hard crank 100 provided in the timer module 16 of FIG. 1 is a functional unit that processes a crank signal in a hardware manner. With this hard crank 100,
The processing of the crank signal shown in FIG. 2 (the generation of an angle signal obtained by dividing the time between crank edges) can be performed by hardware.

FIG. 3 shows the configuration of the hard crank 100. In FIG. 3, a prescaler 101 and a frequency divider 1
02, edge time measurement counter 103, multiplication register (edge time storage register) 104, and multiplication counter 10
5, event counter 106, and guard counter 107
, Reference counter 108 and tracking counter (angle counter)
109 and an ignition / injection angle counter 110. The signal Pφ from the prescaler 101 is
2 to the edge time measurement counter 103.
The signal Pφ is a tracking counter (angle counter) 109
Sent to Further, the crank signal is sent to the edge time measurement counter 103, the event counter 106, and the guard counter 107.

FIG. 4 shows an angle clock (angle signal).
4 shows a time chart of occurrence. FIG. 4 shows the input crank signal, the count value of the edge time measurement counter 103, the stored value of the multiplication register 104, and the multiplication counter 105.
Count value, output signal (multiplication clock) of the multiplication counter 105, n times the value of the guard counter 107, count value of the reference counter 108, count value of the follow-up counter 109, count value of the ignition / injection angle counter 110 Is shown.

The edge time measurement counter 103 shown in FIG.
A crank signal is input to measure a time (pulse interval) between crank edges. More specifically, the edge time measurement counter 103 as a pulse interval measurement means is a counter that counts up in a time-synchronized manner as shown in FIG. 4, and measures a time between crank edges (between falling edges of a crank signal). The measured value is multiplied by 1 / n and transferred to the multiplication register 104 when an edge is input. The transferred data is a multiplication counter 105 which is a down counter.
Is the initial value. As the multiplication value (n value), for example, “3”
2 ".

The multiplication counter 105 shown in FIG. 3 uses the time between crank edges measured by the edge time measurement counter 103 to generate a multiplied clock whose crank edge time is 1 / n. Specifically, the multiplication counter 105
As shown in FIG. 4, the operation of counting down with time synchronization and generating an increased clock when the underflow occurs and repeating the operation of returning the count value to the initial value are repeated. When the next crank edge (falling edge of the crank signal) is input, the value of the multiplication register 104 and the initial value of the multiplication counter 105 are updated to the latest values. As described above, the multiplying counter 105 as the multiplied signal generating means generates a multiplied signal (multiplied clock) having a frequency of an integral multiple until the next pulse based on the current pulse interval by the edge time measuring counter 103.

As shown in FIG. 4, the reference counter 108 in FIG. 3 counts up by a multiplied clock.
The follow-up counter 109 in FIG. 3 counts up with a time synchronous clock (counts with an internal clock). The guard counter 107 is a counter that counts up each time a falling edge of the crank signal is input, and transfers a value n times (multiplied) the value before counting up to the reference counter 108 at the same time as the input of the crank edge. That is, the guard counter 107 counts up with the pulse of the crank signal and generates a guard value that is an integral multiple of the count value when generating the multiplied clock.

As shown in FIG. 4, the count value of the reference counter 108 is determined by the guard counter 1 when the crank edge is input.
It cannot exceed the value transferred from 07 (n times the count value). That is, the reference counter 108 counts up within a range not exceeding the guard value of the guard counter 107. The tracking counter 109 counts up only when the count value is smaller than the count value of the reference counter 108 (counts up within a range not exceeding the count value of the reference counter 108). An angle clock (angle signal) is generated in synchronization with the count-up of the tracking counter 109. Thus, the three counters 10
Angle clocks are generated by 7, 108 and 109.

In the present embodiment, the internal clock (signal Pφ from the prescaler) is set to 20 MHz, and the tracking counter 109 can operate at a higher speed than other counters. In FIG. 4, at the time of deceleration, as the count operation of the reference counter 108 and the follow-up counter 109, the value of the reference counter 108 reaches n times the value of the guard counter 107 before the input of the crank edge. The count-up of 109 is prohibited. In this way, the guard counter 107 makes the reference counter 1
08 and the count-up operation of the tracking counter 109 stops at the multiple. As a result, the follow-up counter 10
The counting operation of No. 9 is stopped to prevent the generation of an angle clock having a certain value or more.

The ignition / injection angle counter 110 in FIG. 3 receives the angle clock from the follow-up counter 109 and counts up (see FIG. 4). Based on the count value of the ignition / injection angle counter 110, ignition / injection control is performed in synchronization with crank angle using a compare register. That is, it controls the injection timing of the fuel injection device that supplies fuel to the engine according to the count value of the ignition / injection angle counter 110, and controls the ignition timing of the ignition device that ignites the air-fuel mixture in the cylinder of the engine. Thus, the ignition / injection angle counter 110 can hardly control ignition / injection and the like in synchronization with the crank angle. As described above, a system for generating a multiplied signal (multiplied clock) at predetermined angular intervals and synchronizing with engine rotation can eliminate a calculation for converting from angle to time, thereby reducing a processing load. In addition, it is possible to improve the accuracy (LSB = 0.1875 ° CA if n = 32).

The value of n times (multiplied) the value of the guard counter 107 is transferred (loaded) to the reference counter 108 when the crank edge is input.
In order to make the counter of the period, the guard counter 107 is set at the crank edge immediately before the crank edge to be reset.
Is reset to “0”.

The event counter 106 shown in FIG. 3 counts up at the falling edge of the pulse of the crank signal and outputs an angle cycle interrupt signal for each edge. Note that the count value of the event counter 106 is initialized in one engine cycle (720 ° CA).

The CPU 11 detects missing teeth of the crank signal from the number of multiplied clocks between the falling edges of the pulses. For example, if the count-up number of the reference counter 108 between crank edges exceeds a predetermined value, it is determined that the tooth is missing.

Next, the engine control E configured as described above will be described.
The operation of the CU (engine control device) will be described. FIG. 5 shows a time chart at the position of the missing teeth of the crank signal.

First, at the timing t10, when the level of the cam signal is at the L level at the falling edge (crank edge) of the pulse immediately after the missing tooth, the CPU 11 determines that the tooth is a missing tooth.
Is reset to “0”. Then, the reference counter 108
Loads the value “0” of the guard counter 107 at the next crank edge (time t11 in the figure) at which the system reset is desired, and if the count value of the follow-up counter 109 reaches the one-cycle guard value in this state. (Figure 2
At timing t5), the follow-up counter 109 is reset to “0” by hardware. When the tracking counter 109 is reset to “0”, a reset signal is sent to the ignition / injection angle counter 110.

This will be described with reference to FIG. The CPU 11 as a determination unit determines the front missing teeth and the back missing teeth of the crank signal using the level of the cam signal at the falling edge (timing of t1 and t2) immediately after the missing tooth of the crank signal. As described above, the determination is made by software, the cam signal level is L, and the missing tooth is determined, whereby the position of the BTDC 6 ° CA (t5) of the fourth cylinder, which is the system initialization position, is set.
At the timing), the follow-up counter 109 is reset in a hardware manner, and the ignition / injection angle counter 110 is simultaneously initialized by sending the reset signal. Also,
By software (by the CPU 11), the reference counter 108 is set to the value corresponding to the missing tooth when the missing tooth is detected, and the guard counter 107 and the reference counter 108 are set to the value corresponding to the missing tooth when the missing tooth is detected. It has become.

As described above, in a system using a crank signal having two missing teeth during 720 ° CA, FIG.
As shown in the time chart, a tracking counter 109 operated by a signal obtained by multiplying the interval between crank edges and an ignition / injection angle counter 110 counting up by an angle clock (angle clock) generated by the counting up of the tracking counter 109. Initialization position is 720 ° C
There is only one location during one cycle of A. In order to determine the initialization position, the missing teeth and the missing teeth are identified by software control using the signal level of the cylinder discrimination signal such as the cam signal, and the initialization is performed when the table is displayed. However, as shown in the time chart of FIG. 6, for example, when noise is superimposed on the cam signal and the signal level at the time of the front / back determination is reversed, the position of the back tooth is originally determined regardless of the timing of the front missing tooth. Erroneously, the tracking counter 109 is not reset, and the tracking counter 109 sticks to the upper limit of 720 ° CA in one cycle during 720 ° CA until the next missing tooth, and the ignition / injection is lost during that time. appear.

That is, at the timing of the missing tooth detection interrupt at t20 in FIG. 6, the level of the cam signal becomes H level due to noise, and it is determined that the tooth is a missing tooth. The guard counter 107 is set to the value of 360 ° CA (the missing tooth). (Equivalent value). Since the reference counter 108 is not reset to “0” at the timing t21 which is the falling edge of the next crank signal, the follow-up counter 109 sticks to the one-cycle guard value and no reset signal is output. Thereby, the ignition / injection angle counter 11
0 sticks to the 1-cycle guard value, the angle coincidence does not occur, and the ignition / injection stops. Since the follow-up counter 109 remains stuck at the one-cycle guard value until the next missing tooth detection, the ignition / injection is stopped for 720 ° CA.

This problem can be solved by recognizing not only the level of the cam signal but also the waveform of the cam signal to determine the cylinder (specifically, by measuring the periods T1 and T2 in FIG. 2). If noise or the like enters the crank signal at a location other than the position of the missing tooth, a problem arises that the angle clock is stopped by erroneously detecting the missing tooth and erroneously determining the cylinder. This will be described with reference to FIG. FIG. 7 is a time chart when noise is included in the crank signal and an erroneous missing tooth is detected.

If noise is present in the crank signal at the timing of t30 in FIG. 7 and a missing tooth is erroneously detected, the cylinder is determined at the erroneously detected location. If it is determined that the tooth is a back missing tooth, the guard counter 107 and the reference counter 1
08 is set to the missing tooth value (“59”, “59 × multiplier”). Thereafter, the follow-up and ignition / injection angle counters 109 and 110 count up, and when a regular back missing tooth is detected at the timing of t31, the back missing tooth value is set in the guard counter 107 and the reference counter 108. However, at this time, since the value has already been counted up from the value corresponding to the missing tooth due to the earlier misdetection of the missing tooth, the value is larger than the value corresponding to the missing tooth when the normal missing tooth is detected. The value to be set is smaller than the current value. The tracking counter 109 is the reference counter 10
Since it is reset only when 8 is reset to "0", the follow-up counter 109 is not reset to the value corresponding to the missing tooth. Therefore, since the reference counter is smaller than the tracking counter, even if the reference counter 108 counts up after t31, the tracking counter 109 is stopped until the timing t32 when the reference counter> tracking counter is established. Since the angle clock is not output when the follow-up counter 109 stops, the ignition / injection angle counter 11
0 also stops, so if the missing tooth is detected immediately after the missing tooth, the worst 720 ° CA tracking counter 109 becomes abnormal. As a result, the ignition / injection angle counter 110 also becomes abnormal during that time, and the ignition / injection output becomes abnormal, causing the worst stop.

As described above, during the period from t30 to t32 in FIG. 7, the tracking and ignition / injection angle counters 109,
When 110 becomes abnormal, the counting operation of both counters 109 and 110 stops during the period from t31 to t32.

Therefore, as a method of returning the follow-up and ignition / injection angle counters 109 and 110 at an early stage, when a value smaller than the present value is set as the value of the reference counter 108 at the time of detecting the missing teeth, noise is included in the crank signal. By setting the following counter 109 and the ignition / injection angle counter 110 to the values corresponding to the missing teeth, it is possible to return the ignition / injection earlier than the detection of the missing teeth (within 360 ° CA). Can be restored).

More specifically, as shown in FIG. 8, when the crank signal is erroneously detected at the timing of t40 and a missing tooth is erroneously detected and the counters 108 to 110 are abnormal, the regular back-up at t41 is performed. By setting the follow-up counter 109 and the ignition / injection angle counter 110 at the missing tooth position to the value corresponding to the missing tooth, the counter 10 must be kept within 360 ° CA.
8 to 110 return to normal. For details, see FIG.
At t40, when the missing tooth is erroneously detected due to noise and the back missing tooth is determined, the value of the reference counter 108 is raised to the value corresponding to the missing tooth, and the value of the follow-up counter 109 is also raised. Then, at the timing of t41, the reference counter 1
By setting the follow-up counter 109 to a value corresponding to the missing tooth together with 08, normal operation is performed after the missing tooth is detected.

FIG. 9 shows a flowchart of the missing tooth detection interrupt. In the missing tooth detection interrupt shown in FIG. 9, the CPU 11 determines whether there is a missing or missing tooth in step 901 and, if the missing tooth is present, sets a value corresponding to the missing tooth in the guard counter 107 and the reference counter 108 in step 905. In the case of a missing tooth, not only the value corresponding to the missing tooth is set in the guard counter 107 and the reference counter 108 in step 902, but in the present embodiment, the following processing is executed.

The CPU 11 starts counting the counter 1 when the missing tooth is erroneously detected.
In order to prevent 08-110 from becoming abnormal, step 9
02, a value corresponding to the missing teeth is set in the guard counter 107 and the reference counter 108, and then in step 903, the current value of the following counter 109 and the missing teeth determination value (“59 + 2”) are set.
× multiplier number ”) and compare the current tracking counter 109
Is determined to be greater than the value of the missing tooth determination value. In other words, if the value of the follow-up counter 109 should be equal to or less than the determination value of the missing tooth, if it is normal, it can be determined that the crank signal is abnormal when the value of the follow-up counter 109 becomes larger than the determination value. The determination value at this time is the value of the regular missing tooth position plus “2”, but the determination value may be the value of the regular missing tooth position plus “1”.

When the CPU 11 determines in step 903 that there is an abnormality (at the timing of t41 in FIG. 8).
The routine proceeds to step 904, where the tracking counter 109 and the ignition
The value corresponding to the missing tooth is forcibly written into the injection angle counter 110. On the other hand, if it is determined in step 903 that it is normal, the CPU 11 does not perform the processing of step 904, but follows the follow-up counter 109 and the ignition / injection angle counter 1
Leave 10 as it is. This is to reduce the processing load and to avoid the occurrence of a clock when writing a value to the tracking counter 109, and to write the value to the tracking counter 109 only when it is truly determined that there is an abnormality. ing.

If the CPU 11 determines that there is a missing tooth in step 901 as described above, the present system determines that the missing tooth position is the system initialization position. Since it is possible to always return to the tooth position (both front and rear missing teeth), the following counter 109 and the ignition / injection angle counter 110 are written in the guard counter 107 and the reference counter 108 simply by writing the corresponding values to the guard counter 107 and the reference counter 108 in step 905. No value is written.

As described above, the angle counters 109 and 11
In a system in which a hard output is made at the angle coincidence between 0 and the ignition / injection timing, etc., in a system in which a crank signal having two missing teeth is used between 720 ° CA and a front / back side is determined by a cylinder determination signal such as a cam signal. When the generation of the angle clock is stopped due to false detection of missing teeth due to noise in the crank signal or the like, the angle counters 109 and 110 are returned earlier than the hardware initialization position (360 ° CA).
), Normalize the angle control early and
The period during which the injection control is stopped can be shortened.

As described above, this embodiment has the following features. (A) In a system in which the reference counter 108 and the follow-up counter 109 are initialized with the missing tooth positions in the table at every 720 ° CA of the crank signal, C as the count value setting means
In step 901 in FIG.
When it is determined that there is a back missing tooth at every 20 ° CA, the count value of the reference counter 108 is set to a value corresponding to the back missing tooth in step 902, and the count value of the follow-up counter 109 is set to a predetermined value in step 903. Is exceeded, the count value of the follow-up counter 109 is set to a value corresponding to the missing tooth on the back in step 904. Therefore, the tracking counter 1
09 is counted up within a range not exceeding the count value of the reference counter 108. If noise is detected in the crank signal from the front missing tooth position to the back missing tooth position and the missing tooth on the back side is erroneously detected, the reference counter 109 is used. When the count value of 108 is set to a value corresponding to the back missing tooth, the tracking counter 109 performs a counting operation until the subsequent back missing tooth is properly detected, and the reference value is set when the back missing tooth is detected. If the count value of the counter 108 is set to a value corresponding to the missing tooth on the back, the counting operation of the tracking counter 109 is not performed until the count value of the reference counter 108 exceeds the count value of the tracking counter 109, but the missing tooth on the back is missing. When the missing tooth on the back after the false detection of
Since the count value of the follow-up counter 109 exceeds the predetermined value, the count value of the follow-up counter 109 is set to a value corresponding to the missing tooth on the back, and the count operation of the follow-up counter 109 is started. In this manner, when determining the back missing tooth based on the crank signal, even if noise is applied to the crank signal and the back missing tooth is erroneously detected, 360 ° C.
The tracking counter 109 can be operated in a normal state within A. As a result, even if noise is included in the crank signal, the engine control can be appropriately performed, and the engine control device is resistant to noise.

FIG. 9 is a flow chart in the case where the position of the missing tooth is the initialization position. If the initialization position is shifted from the position of the missing tooth, the missing tooth is processed after the processing of step 905 in FIG. What is necessary is just to perform the setting process of a position equivalent value.
In short, the reference counter 108 and the follow-up counter 109 are based on the tooth missing tooth at every 720 ° CA of the crank signal.
What is necessary is just to initialize every 20 degree CA. (Second Embodiment) Next, a second embodiment will be described with reference to the first embodiment.
The following description focuses on the differences from this embodiment.

In the present embodiment, if the value of the card counter 107 is not a regular value, it is determined that a missing tooth has been erroneously detected by a missing tooth detection interrupt (when the normal missing tooth detection condition is not satisfied), and the guard is detected. The setting of the missing tooth equivalent value in the counter 107 and the reference counter 108 is prohibited, so that even if a missing tooth is erroneously detected, it is immediately restored.

More specifically, as shown in FIG. 10, noise is present in the crank signal, and the level of the cam signal is H level at the time of interruption of missing tooth detection at the timing of t50. The counter 107 and the reference counter 108 are set to the value corresponding to the missing tooth. In the present embodiment, it is determined whether the value of the guard counter 107 is within the predetermined range X and whether the interrupt is a normal missing tooth is determined. Is determined, the guard counter 107 and the reference counter 108 are prohibited from being set to the value corresponding to the missing tooth. 109,
110 is prevented from becoming abnormal. That is, in this embodiment, as compared with the comparative example in FIG.
If it does not, it is prohibited to set it to the value equivalent to the missing tooth.

As a result, in FIG. 7, when the crank signal contains noise after the missing tooth and the missing tooth is erroneously detected, the count-up of the following counter 109 is stopped while the following counter> the reference counter. Then this can be avoided.

FIG. 11 shows a flowchart of the missing tooth detection interrupt. In the missing tooth detection interrupt in FIG. 11, the CPU 11 determines whether a missing tooth or a missing tooth is determined in step 1001 and, if determined, immediately sets a corresponding missing tooth value and a corresponding missing tooth value in steps 1003 and 1005. Instead of:

Counters 109 and 11 due to erroneous detection of missing teeth
In order to avoid the abnormality of 0, the CPU 11 first determines whether the tooth is a front missing tooth or a back missing tooth in step 1001. It is determined whether the value is a tooth equivalent value ("59"). The judgment value at this time has a margin of ± 2 in order to restore the normal state with a normal missing tooth even if noise enters. This margin may be ± 1 or the like in addition to ± 2. Then, the CPU 11 sets a value corresponding to the back missing tooth in the guard counter 107 and the reference counter 108 in step 1003 if the result is normal in step 1002. The count value setting process in step 1003 is not performed (setting is prohibited).

If it is determined in step 1001 that there is a missing tooth, the CPU 11 sets the guard counter 107 to a value corresponding to the missing tooth (“119”) in step 1004.
Is determined. The judgment value at this time is provided with a margin of ± 2 (± 1 or the like is also possible) in order to restore the normal state with a normal missing tooth even if noise enters similarly to the back missing tooth. Then, the CPU 11 determines in step 1004
In step 1005, a value corresponding to a missing tooth is set in the guard counter 107 and the reference counter 108 in step 1005. When it is determined that there is an abnormality, it is determined that a missing tooth has been detected due to noise, and the count value is set in step 1005. No processing (setting prohibited).

Note that steps 1002 and 1002 in FIG.
In 4, the count value of the guard counter 107 (a counter that counts with a pulse of a crank signal) is used, but the count value of the follow-up counter 109 may be used. In steps 1003 and 1005, the count value of the reference counter 108 is set to a missing tooth equivalent value. However, the count value of the following counter 109 is set to a missing tooth equivalent value, or the count values of the reference and following counters 108 and 109 are set to a missing tooth equivalent value. It may be a value.

As described above, this embodiment has the following features. (A) In a system in which the reference counter 108 and the follow-up counter 109 are initialized with the missing tooth positions in the table at every 720 ° CA of the crank signal, C as the count value setting means
When the PU 11 determines in step 1001 of FIG. 11 that there is a missing tooth on the back of each 720 ° CA of the crank signal,
Only when the count value of the guard counter 107 or the follow-up counter 109 is within a predetermined range in step 1002, at step 1003, at least one of the count values of the reference counter 108 and the follow-up counter 109 is set to a value corresponding to the missing tooth on the back. Set. In other words, when it is determined that there is a missing tooth on the back of each 720 ° CA of the crank signal, if the count value of the guard counter 107 or the count value of the follow-up counter 109 does not fall within a predetermined range, the reference counter 108 and At least one of the count values of the follow-up counter 109 is not set to a value corresponding to the missing tooth on the back. That is, when noise is detected in the crank signal and a missing tooth on the back side is erroneously detected, the guard counter 107
And the count value of the follow-up counter 109 does not fall within the predetermined range, and at least one of the count values of the reference counter 108 and the follow-up counter 109 is not set to a value corresponding to the missing tooth on the back. Therefore, when the back missing tooth is determined based on the crank signal, the counter can be operated in a normal state even when noise is present in the crank signal and the back missing tooth is erroneously detected. As a result, even if noise is included in the crank signal, the engine control can be appropriately performed, and the engine control device is resistant to noise. (B) Further, the CPU 11 executes step 100 in FIG.
When it is determined in step 1 that there is a missing tooth in the table at every 720 ° CA of the crank signal, only when the count value of the guard counter 107 or the following counter 109 is within a predetermined range in step 1004, the reference counter is determined in step 1005. Since at least one of the count values of the tracking counter 108 and the follow-up counter 109 is set to a value corresponding to the missing tooth in the table, even if noise is detected in the crank signal and the missing tooth in the table is erroneously detected, the value corresponding to the incorrect missing tooth is obtained. Is not set,
The counter can be operated in a normal state.

In the above description, the reference position portion of the crank signal is a missing tooth from which a pulse is extracted in the middle of a pulse train. However, the present invention is not limited to this. A reference position portion having unequal pulse intervals may be formed in the middle of a pulse train at predetermined angular intervals.

Further, the discrimination between the missing tooth on the front and the missing tooth on the back of the crank signal is made based on the level of the cam signal at the missing tooth. In addition, for example, the count value of the event counter 106 in FIG. (The number of edge inputs).

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an engine control ECU according to an embodiment.

FIG. 2 is a time chart of one engine cycle (720 ° CA).

FIG. 3 is a configuration diagram of a hard crank.

FIG. 4 is a time chart for explaining generation of an angle clock by a hard crank.

FIG. 5 is a time chart for explaining a reset process of an angle counter at the time of a missing tooth.

FIG. 6 is a time chart for explaining a situation when noise is present on the cam signal.

FIG. 7 is a time chart for explaining a situation when noise is present on the crank signal.

FIG. 8 is a time chart for explaining an angle counter process when an erroneous determination is made due to noise on a crank signal.

FIG. 9 is a flowchart showing processing in interrupting missing teeth.

FIG. 10 is a time chart for explaining an angle counter process when noise is included in a crank signal and an erroneous determination is made according to the second embodiment;

FIG. 11 is a flowchart showing processing in missing tooth interruption.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine control ECU, 10 ... Microcomputer, 11 ... CP
U, 16: timer module, 100: hard crank, 103: edge time measurement counter, 104: multiplication register, 105: multiplication counter, 107: guard counter, 108: reference register, 109: follow-up counter,
110 ... Ignition / injection angle counter.

Claims (5)

[Claims] 1. Crank signal generating means for generating a crank signal having a reference position portion at every 360 ° CA in a pulse train at predetermined angular intervals corresponding to rotation of a crankshaft of a four-cycle engine; A pulse interval measuring means for inputting and measuring a pulse interval; a multiplied signal generating means for generating a multiplied signal of an integral multiple frequency until the next pulse based on the current pulse interval by the pulse interval measuring means; A reference counter that counts with a multiplied signal; and a count operation that does not exceed the count value of the reference counter with an internal clock. The reference counter and the reference position in the table for each 720 ° CA of the crank signal are used together with the reference counter. A tracking counter initialized at every 720 ° CA, and a reference position portion at the back of each 720 ° CA of the crank signal. When it is determined, the count value of the reference counter is set to a value corresponding to the back reference position, and when the count value of the tracking counter exceeds a predetermined value, the count value of the tracking counter is set to a value corresponding to the back reference position. An engine control device comprising: a count value setting unit that sets the count value. 2. A crank signal generating means for generating a crank signal having a reference position portion at every 360 ° CA in the middle of a pulse train at a predetermined angular interval corresponding to the rotation of a crankshaft of a four-cycle engine; A pulse interval measuring means for inputting and measuring a pulse interval; a multiplied signal generating means for generating a multiplied signal of an integral multiple frequency until the next pulse based on the current pulse interval by the pulse interval measuring means; A reference counter that counts with a multiplied signal; and a count operation that does not exceed the count value of the reference counter with an internal clock. The reference counter and the reference position in the table for each 720 ° CA of the crank signal are used together with the reference counter. A tracking counter initialized at every 720 ° CA, and a reference position portion at the back of each 720 ° CA of the crank signal. Is determined, the count value of the reference counter and / or the counter value of at least one of the reference counter and the follow-up counter is changed only when the count value of the follow-up counter or the count value of the counter that counts with the pulse of the crank signal is within a predetermined range. An engine control device, comprising: a count value setting unit that sets a value corresponding to a back reference position. 3. A counter that counts with a pulse of the crank signal, generates a guard value that is an integral multiple of the count value when the multiplied signal is generated, and counts the count value with the pulse of the crank signal. The engine control device according to claim 2, wherein the engine control device is a guard counter for counting a reference counter within a range not exceeding a value. 4. When the crank signal is determined to be at a reference position in the table for each 720 ° CA, the count value of the tracking counter or the count value of a counter that counts with a pulse of the crank signal is a predetermined value. 4. The engine control according to claim 2, further comprising means for setting a count value of at least one of the reference counter and the follow-up counter to a value corresponding to a reference position in a table only when the value is within the range. apparatus. 5. A cylinder discriminating signal generating means for generating cylinder discriminating signals having different levels at a reference position in the table for each 720 ° CA of the crank signal and a reference position on the back for each 720 ° CA; Determining means for determining a reference position on the front and a reference position on the back of the crank signal based on the level of the cylinder determination signal at the reference position of the signal. The engine control device according to claim 1.