JP6911627B2 - AD conversion processing device - Google Patents

Description

The present disclosure relates to a technique for AD-converting a detection signal of a sensor that detects an operating state of an engine in synchronization with a multiplication signal having a period obtained by dividing the period of a crank signal by a predetermined multiplication number.
Regarding.

In order to control the operating state of the engine with high accuracy, it is known that the operating state of the engine is controlled in synchronization with a multiplication signal having a period shorter than the crank signal, which is obtained by dividing the signal cycle of the crank signal by a multiplication factor. ing.

In the technique described in Patent Document 1, the output signal of the in-cylinder pressure sensor is AD-converted in synchronization with a multiplication signal having a period shorter than the crank signal, and the inside of the cylinder is based on the change in the in-cylinder pressure indicated by the AD conversion data. The combustion state of is being analyzed.

Since the multiplication signal is a signal having a period obtained by dividing the signal period between the previous crank signal and the current crank signal by a multiplication factor, when the engine accelerates rapidly, between the current crank signal and the next crank signal. The next crank signal may occur before the multiplication signal of the multiplication number is generated.

Then, among the AD conversions that are executed a target number of times between the crank signals in synchronization with the multiplication signal, the AD conversions are not executed several times during the signal cycle of the crank signals and exit.

In the technique described in Patent Document 1, when the AD conversion is removed due to the acceleration of the engine, 0 is set as an abnormal value that the output signal of the in-cylinder pressure sensor cannot take in the storage destination for storing the AD-converted value.

Then, when the AD conversion value of the stored in-cylinder pressure sensor is referred to and the abnormal combustion determination process is performed, if the AD conversion is omitted and 0 is stored as the AD conversion value, the crank angle without the AD conversion is removed. The AD conversion value at the position is interpolated by the AD conversion value before and after the AD conversion is omitted.

Japanese Patent No. 05799891

When the AD conversion is executed in synchronization with the multiplication signal obtained by dividing the signal period of the crank signal by a multiplication factor as in the technique described in Patent Document 1, when the engine accelerates, it synchronizes with the crank angle represented by the multiplication signal. The AD conversion to be performed is performed at an angle position deviated from the actual angle position of the crankshaft.

Therefore, the AD conversion value at the angle position where it is estimated that the AD conversion has been lost based on the AD conversion value obtained by the AD conversion executed at the actual angle position of the crank shaft before and after the AD conversion is lost and the angle position deviated from the AD conversion. When interpolating, there is a problem that the interpolated AD conversion value also becomes the AD conversion value at the angle position deviated from the actual angle position of the crank shaft.

In the present disclosure, even when the AD conversion of the target number of times cannot be executed in synchronization with the multiplication signal of the crank signal due to the acceleration of the engine, the target number of times is as much as possible at the actual angle position of the crankshaft during the signal cycle of the crank signal. Provided is a technique for acquiring an AD conversion value.

One aspect of the present disclosure includes an angle counter (52), an AD conversion unit (70), an omission determination unit (60, S466), a timing setting unit (60, S490 to S494), and an interpolation unit (60, S502 to S514). It has.

The angle counter synchronizes the signal cycle of the crank signal generated at a predetermined angular interval with the rotation of the crankshaft of the engine with the multiplication signal of the cycle divided by a predetermined multiplication number, and counts the multiplication number during the signal period. do. The AD conversion unit AD-converts the detection signal every time the angle counter counts a predetermined number of counts so that the detection signal of the sensor that detects the operating state of the engine is AD-converted by the target number of times during the signal cycle.

When the omission determination unit detects the crank signal, it determines whether or not an AD conversion omission that the AD conversion unit cannot perform AD conversion has occurred during the signal cycle because the generation timing of the crank signal has been advanced due to the acceleration of the engine. ..

When the omission determination unit determines that the AD conversion omission has occurred, the timing setting unit sets the target number of times and the conversion timing to be AD-converted in synchronization with the angular position of the crankshaft during the signal cycle. ..

The interpolation unit interpolates the AD conversion value at the conversion timing set by the timing setting unit based on the AD conversion value that has been AD-converted by the AD conversion unit.
Here, when the generation timing of the crank signal is earlier and the signal cycle of the crank signal is shortened, the timing of AD conversion by the AD conversion unit in synchronization with the multiplication signal becomes later than the timing of the actual angular position represented by the crank signal. There is.

Therefore, according to the configuration of the present disclosure, when the AD conversion is removed, the AD conversion unit sets the target number of times and the conversion timing to be AD-converted in synchronization with the angular position of the crankshaft during the signal cycle, and the conversion timing is set. The AD conversion value is interpolated based on the AD conversion value that has been AD-converted by the AD conversion unit. Therefore, based on the AD-converted AD-converted value, the AD-converted value can be acquired at a timing as close as possible to the actual angular position of the crankshaft.

In addition, the reference numerals in parentheses described in this column and the scope of claims indicate the correspondence with the specific means described in the embodiment described later as one embodiment, and the technical scope of the present disclosure is defined. It is not limited.

The flock diagram which shows the AD conversion processing apparatus by this embodiment. A flowchart showing an edge detection process. A flowchart showing the compare match process. The flowchart which shows the AD acquisition interval time calculation process. The flowchart which shows the omission determination and AD conversion value interpolation processing. The flowchart which shows the AD acquisition timing interpolation processing. A flowchart showing AD conversion value interpolation and storage processing. A time chart showing AD conversion processing. A time chart for explaining the effect of this embodiment. A characteristic diagram showing the relationship between the crank angle and the AD conversion value.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.
[1. Constitution]
The ECU 10 shown in FIG. 1 is mounted on a vehicle and includes input circuits 12 and 14, an output circuit, and a microcomputer 20. ECU is an abbreviation for Electronic Control Unit, and microcomputer is an abbreviation for microcomputer.

The input circuit 12 inputs a crank signal generated at a predetermined angle interval with the rotation of the crankshaft from the crank angle sensor. The input circuit 14 inputs a detection signal detected by an in-cylinder pressure sensor installed in each cylinder. The in-cylinder pressure sensor detects the in-cylinder pressure of each cylinder as the operating state of the engine.

The crank signal is a pulse signal generated when a crank angle sensor detects teeth installed at regular angular intervals on the outer circumference of a crank rotor that rotates with a crankshaft. The crank rotor has a tooth missing portion in which teeth are continuously missing.

Therefore, the crank signal has a pulse train having a pulse generated every time the crankshaft rotates by a certain angle, and a tooth missing portion in which the pulse is not generated and the angular interval between the pulses is larger than that of the pulse train. ing. The missing tooth portion indicates a reference position in the rotation direction of the crankshaft.

The output circuit 16 outputs a signal output by the compare unit 62 of the timer control module 40 to the ignition module and the injection module. The ignition module is a spark plug and a drive circuit for the spark plug. The injection module is an injector and a drive circuit for the injector. The signal output by the compare unit 62 indicates the angle timing at which the ignition module executes ignition of the fuel and the angle timing at which the injection module executes fuel injection.

The microcomputer 20 includes a main CPU 30, a RAM 32, a ROM 34, a timer control module 40, an AD conversion unit 70, and a DMA unit 80. The main CPU 30 and the timer control module 40 are general-purpose processing devices.

Each function of the microcomputer 20 is realized by executing a program in which the main CPU 30 and the timer control module 40 are stored in a non-transitional substantive recording medium such as a ROM or a flash memory. When this program is executed, the method corresponding to the program is executed.

The method for realizing these elements constituting the microcomputer 20 is not limited to software, and some or all of the elements may be realized by using one or more hardware. For example, when the above function is realized by an electronic circuit which is hardware, the electronic circuit may be realized by a digital circuit including a large number of logic circuits, an analog circuit, or a combination thereof.

The main CPU 30 executes engine control by executing a control program stored in the ROM 34. For example, the main CPU 30 sets the angle timing at which the ignition control and the fuel injection control are executed next time as the engine control in the compare unit 62 via the timer-dedicated processor 60.

The RAM 32 of the main CPU 30 stores data that the main CPU 30 and the timer-dedicated processor 60 commonly refer to.
The timer control module 40 includes an edge detection unit 42, an angle clock generation unit 44, a counter unit 50, a timer-dedicated processor 60, a compare unit 62, and a RAM and ROM (not shown).

The edge detection unit 42 detects the edge of the pulse of the crank signal. The edge of the crank signal detected by the edge detection unit 42 may be either a rising edge or a falling edge. The edge detection unit 42 stores the time when the edge of the crank signal is detected.

The counter unit 50 includes various counters. The counter unit 50 includes, for example, an angle counter 52 and a time counter 54. The angle counter 52 counts the number of clocks of the angle clock in synchronization with the angle clock generated by the angle clock generation unit 44. The time counter 54 counts the number of clocks in synchronization with the operating clock of the timer-dedicated processor 60.

The compare unit 62 includes various compare registers (not shown). The compare unit 62 compares the value set in the compare register by the timer-dedicated processor 60 with the value of the angle counter 52 or the time counter 54 of the counter unit 50 corresponding to the set value.

When the value of the compare register and the value of the corresponding counter match, the compare unit 62 outputs an output signal for the injection module and the ignition module to the output circuit 16, or AD-converts the in-cylinder pressure signal to the AD conversion unit 70. It is instructed to do so, or the timer-dedicated processor 60 is requested to execute the process corresponding to the matching between the value of the compare register and the value of the corresponding counter.

When an execution event occurs, the timer-dedicated processor 60 executes processing corresponding to the execution event in the order in which the execution event occurs, based on a control program stored in a ROM (not shown).

For example, the timer-dedicated processor 60 sets the execution timing of engine control in the compare unit 62 at an angular timing or a time timing in response to a request from the main CPU 30. Further, when the edge detection unit 42 detects the edge of the pulse of the crank signal, the timer-dedicated processor 60 executes the edge detection process described later.

The timer-dedicated processor 60 divides the edge-to-edge time, which is the signal cycle of the clock signal between the above and the present time, by the edge-to-edge count number, which is a predetermined multiple, and the edge detection unit 42 determines the edge of the next crank signal. It is set to the clock period of the angular clock generated by the angular clock generation unit 44 before the detection. That is, the angular clock is a multiplication signal obtained by dividing the signal period of the crank signal by a predetermined multiplication number.

Further, when the timer-dedicated processor 60 counts a predetermined number of counts in the compare register of the compare unit 62 so that the target number of times and the AD conversion unit 70 perform AD conversion during the signal cycle of the crank signal. Set the counter value of. When the counter value set in the compare register and the counter value of the angle counter 52 match, the compare unit 62 instructs the AD conversion unit 70 to perform AD conversion of the in-cylinder pressure signal.

The angle clock generation unit 44 includes a target counter (not shown) inside. Each time the edge detection unit 42 detects the edge of the crank signal, the timer-dedicated processor 60 sets the target counter value to the target counter by adding the number of counts between the target edges to be counted in the signal cycle of the crank signal. ..

The target edge-to-edge count number is set in the ROM 34 in advance. The angle clock generation unit 44 generates an angle clock at a cycle calculated by the timer-dedicated processor 60 until the count number of the angle counter 52 reaches the target counter value set in the target counter.

The angle clock generation unit 44 stops generating the angle clock when the counter value of the angle counter 52 reaches the target counter value set in the target counter before the edge detection unit 42 detects the edge of the crank signal.
When the edge detection unit 42 detects the edge of the crank signal and the counter value of the angle counter 52 does not reach the target counter value set in the target counter, the angle clock generation unit 44 uses the counter of the angle counter 52. Shorten the period of the angular clock so that the value reaches the target counter value quickly.

The AD conversion unit 70 AD-converts the in-cylinder pressure signal input by the input circuit 14 by a command from the compare unit 62. The DMA unit 80 transfers the AD conversion value of the in-cylinder pressure signal AD-converted by the AD conversion unit 70 to the RAM.

[2. process]
(1) Edge detection process When the edge detection unit 42 detects the edge of the crank signal, the edge detection unit 42 requests the timer-dedicated processor 60 to execute the edge detection process shown in the flowchart of FIG. The timer-dedicated processor 60 executes the edge detection process according to the request from the edge detection unit 42 unless other processes are being executed.

The timer-dedicated processor 60 sets the edge detection flag on in S400 and turns on the initial AD acquisition flag in S402.
In S404, the timer-dedicated processor 60 stores the edge information of the previous crank signal in the RAM 32. The previous edge information is the time when the edge of the previous crank signal was detected and the value of the angle counter 52 when the edge was detected.

In S406, the timer-dedicated processor 60 acquires the edge information of the crank signal this time. The edge information of the crank signal this time is the time when the edge of the crank signal is detected this time and the value of the angle counter 52 when the edge is detected.

In S408, the timer-dedicated processor 60 calculates the edge-to-edge time, which is the time interval between the edge of the previous crank signal and the edge of the current crank signal, by the following equation (1).
Edge-to-edge time = current edge detection time-previous edge detection time ... (1)
In S410, the timer-dedicated processor 60 stores in the RAM 32 the time of one count counted by the angle counter 52 between the previous crank signal and the current crank signal, that is, the period of the angle clock as the previous one count time.

In S412, the timer-dedicated processor 60 calculates one count time for the angle counter 52 to count with one count between the current crank signal and the next crank signal by the following equation (2).

1 count time of angle counter = time between edges / number of counts between target edges
... (2)
The edge-to-edge time of the equation (2) is a value calculated by the equation (1) in S408, and the target edge-to-edge count number is the target count number counted by the angle counter 52 between the crank signals.

In S414, the timer-dedicated processor 60 sets the 1 count time calculated in S412 as the period of the angle clock generated by the angle clock generation unit 44. In S416, the timer-dedicated processor 60 calculates the next target counter value counted by the angle counter 52 when the edge detection unit 42 detects the next crank signal by the following equation (3).

Next target counter value = Previous target counter value + Target edge-to-edge count ... (3)
(2) Compare Match Process The compare match process of FIG. 3 is executed when the compare unit 62 compares and matches the counter value of the angle counter 52 with the value set in the AD conversion compare register. When the counter value of the angle counter 52 and the value of the AD conversion compare register match, the AD conversion unit 70 AD-converts the in-cylinder pressure signal.

In S420, the timer-dedicated processor 60 executes the AD acquisition interval time calculation process. The AD acquisition interval time calculation process is a process in which the AD conversion unit 70 calculates the interval time for AD conversion of the in-cylinder pressure signal, and the details will be described later.

In S422, the timer-dedicated processor 60 cannot execute AD conversion because the AD acquisition interval time calculated in S420 is short. Performs interpolation processing. Details of the omission determination process and the AD conversion value interpolation process will be described later.

In S424, the timer-dedicated processor 60 calculates the AD acquisition counter value, which is the counter value of the angle counter 52 when the AD conversion unit 70 executes the AD conversion next time, by the following equation (4).

AD acquisition counter value (n)
= AD acquisition counter value (n-1) + number of counts between AD acquisition ... (4)
In the equation (4), the AD acquisition counter value (n-1) represents the current AD acquisition counter value, and the AD acquisition counter value (n) represents the next AD acquisition counter value.

Further, in the equation (4), the AD acquisition count number is a predetermined count number counted by the angle counter 52 at the interval at which the AD conversion unit 70 executes the AD conversion, and is a fixed value. The AD acquisition count number is a fixed value obtained by dividing the target edge count number described above by the edge AD acquisition number of times the AD conversion unit 70 executes AD conversion during the signal cycle of the crank signal. In this embodiment, the number of edge-to-edge AD acquisitions is set to 6.

In S426, the timer-dedicated processor 60 sets the AD acquisition counter value (n) calculated in S424 in the corresponding compare register of the compare unit 62.
(3) AD acquisition interval time calculation process The AD acquisition interval time calculation process of FIG. 4 is executed in S420 of FIG.

In S430, the timer-dedicated processor 60 determines whether or not the edge detection flag is on. The edge detection flag is set to on in S400 of the edge detection process of FIG. 2 when the edge detection unit 42 detects the edge of the crank signal.

Then, the edge detection flag is set to on in the edge detection process of FIG. 2 after the edge detection unit 42 detects the edge of the crank signal, and is set to off in S442 described later in the second main process. ..

When the determination in S430 is No, that is, when the edge detection flag is off, the timer-dedicated processor 60 in S432 calculates the AD acquisition interval time (n) by the following equation (5).
AD acquisition interval time (n) = 1 count time x number of counts between AD acquisition ... (5)
In the equation (5), the 1-count time is the 1-count time of the angle counter 52 calculated in S412 of FIG. 2, and represents the period of the angle clock.

When the determination in S430 is Yes, that is, when the edge detection flag is on, the timer-dedicated processor 60 in S434 determines whether or not the initial AD acquisition flag is on. When the edge detection unit 42 detects the edge of the crank signal, the first AD acquisition flag is set to ON in S402 of the edge detection process of FIG.

Then, the first AD acquisition flag is set to ON in the edge detection process of FIG. 2 after the edge detection unit 42 detects the edge of the crank signal, and then is set to OFF in S442 described later in the first main process. ..

If the determination in S434 is No, that is, the first AD acquisition flag is off and the first main process has been executed, the process shifts to S444.
If the determination in S434 is Yes, that is, the first AD acquisition flag is on, and this process is executed for the first time after the edge detection unit 42 detects the edge of the crank signal, the timer-dedicated processor 60 in S436 , The normal speed count number counted by the angle counter 52 in the previous 1 count time stored in S410 of FIG. 2 is calculated by the following equation (6).

Normal speed count = Edge detection counter value-AD acquisition counter value (n-1) ... (6)
In the equation (6), the edge detection counter value indicates the counter value of the angle counter 52 when the edge detection unit 42 detects the edge of the crank signal this time. The AD acquisition counter value (n-1) indicates the counter value of the angle counter 52 when the AD conversion is executed by the previous compare match.

As shown in FIG. 8, when the edge detection unit 42 detects the edge of the crank signal, if the angle counter 52 reaches the target counter value, the normal speed count number matches the AD acquisition count number. ..

On the other hand, as shown in FIG. 9, when the edge detection unit 42 detects the edge of the crank signal before the angle counter 52 reaches the target counter value because the engine accelerates rapidly, the normal speed count number is AD acquired. It will be less than the number of interim counts.

In S438, the timer-dedicated processor 60 executes AD conversion next as a process when the edge detection unit 42 detects the edge of the clock signal before the angle counter 52 reaches the target counter value, n = 4 in FIG. The period of the angle clock is shortened by the angle clock generation unit 44 until the timing indicated by the above, and the number of run-up counts counted by the angle counter 52 is calculated by the following equation (7).

Run-up count = AD acquisition count-Normal speed count ... (7)
In S440, the timer-dedicated processor 60 has an interval time between the previous AD conversion time and the current AD conversion time in FIG. 8, and n = 4 set as the previous AD conversion time and the current AD conversion in FIG. The interval time with the indicated timing time is calculated by the following equation (8).

AD acquisition interval time (n)
= (Last 1 count time x normal speed count)
+ (1 count time for running up x number of counts for running up) ・ ・ ・ (8)
In the equation (8), the run-up 1 count time is a fixed value, and the angle clock generation unit 44 sets a time shorter than the normal angle clock cycle.

In S442, the timer-dedicated processor 60 turns off the initial AD acquisition flag.
In S444, the timer-dedicated processor 60 determines whether or not the following equation (9) is satisfied.

n = number of AD acquisitions between edges + 1 ... (9)
As shown in FIG. 8, if the angle counter 52 reaches the target counter value when the edge detection unit 42 detects the edge of the crank signal, the number of edge-to-edge AD acquisitions is 6 as described above in the present embodiment. Therefore, n = 7 in the equation (9). If n = 7, the determination of S444 is Yes.

On the other hand, as shown in FIG. 9, when the edge detection unit 42 detects the edge of the crank signal before the angle counter 52 reaches the target counter value because the engine accelerates rapidly, n <7. If n <7, the determination in S444 is No.

When the determination in S444 is No, that is, n <7 and n is smaller than (the number of AD acquisitions between edges + 1), the timer-dedicated processor 60 in S446 uses the AD acquisition interval time (n) according to the following equation (10). ) Is calculated.

AD acquisition interval time (n)
= 1 count time running up x number of counts between AD acquisition ・ ・ ・ (10)
When n <7, S446 is executed until n is added and n = 7 in the process of FIG. 5 described later.

When the determination in S444 is Yes, that is, n = 7, and n is equal to (the number of AD acquisitions between edges + 1), the timer-dedicated processor 60 in S448 sets the AD acquisition interval time (n) by the following equation (11). calculate.

AD acquisition interval time (n)
= 1 count time x number of counts during AD acquisition ... (11)
In S450, the timer-dedicated processor 60 turns off the edge detection flag. As a result, the determination of S430 becomes No until the edge detection unit 42 next detects the edge of the crank signal.

(4) AD conversion omission determination process and AD conversion value interpolation process The AD conversion omission determination process and AD conversion value interpolation process of FIG. 5 are executed in S422 of FIG.

In S460, the timer-dedicated processor 60 determines whether or not n = (number of edge-to-edge AD acquisitions + 1) represented by the equation (9) is satisfied. In the present embodiment, the number of edge-to-edge AD acquisitions = 6.

When the determination in S460 is No, that is, when n <7, the timer-dedicated processor 60 increments n by +1 in S462.
When the determination in S460 is Yes, that is, n = 7, in FIG. 8, the edge detection unit 42 detects the edge of the crank signal, and then the AD conversion is executed twice. On the other hand, when n = 7, in FIG. 9, the edge detection unit 42 detects the edge of the crank signal, and then the AD conversion is executed once.

When the determination in S460 is Yes, that is, when n = 7, the timer-dedicated processor 60 sets i to 0 in S464. Then, in S466, the timer-dedicated processor 60 determines whether or not the following equation (12) is satisfied. The AD acquisition interval time (i) is a value calculated by the AD acquisition interval time calculation process of FIG.

AD acquisition interval time (i) ≤ AD conversion execution time ... (12)
In the formula (12), the AD conversion execution time represents the time required for the AD conversion unit 70 to perform AD conversion of the in-cylinder pressure signal. Therefore, if the equation (12) is not satisfied, it indicates that the AD conversion corresponding to i at that time has been executed, and if the equation (12) is satisfied, the AD conversion corresponding to i at that time is not executed. It shows that.

As shown in FIG. 8, if the angle counter 52 reaches the target counter value when the engine does not accelerate rapidly and the edge detection unit 42 detects the edge of the crank signal, i = 0 to i = 7 Equation (12) holds.

As shown in FIG. 9, when the edge detection unit 42 detects the edge of the crank signal before the angle counter 52 reaches the target counter value due to the rapid acceleration of the engine, AD is acquired in one count time after running up. From the value of i calculated for the interval time, the determination of S466 is Yes. If the determination in S466 is Yes, the process proceeds to S472.

When the determination in S466 is No, that is, when the AD acquisition interval time (i) is longer than the AD conversion execution time, the timer-dedicated processor 60 determines whether or not i = n in S468. When the determination in S468 is Yes, that is, when i = n, the equation (12) holds for all the AD acquisition interval times (i), so the process shifts to S476. In S468, n = 7.

If the determination in S468 is No, that is, i = n, the timer-dedicated processor 60 increments i by +1 in S470 and returns the process to S466.
In S472, the timer-dedicated processor 60 executes the AD acquisition timing interpolation process. The details of the AD acquisition timing interpolation process will be described later.

In S474, the timer-dedicated processor 60 executes AD conversion value interpolation processing and storage processing. Details of the AD conversion value interpolation processing and the storage processing will be described later. When S474 is completed, the process shifts to S476.

It should be noted that S472 and S474 are executed when the determination of S466 is Yes, that is, as shown in FIG. 9, because the engine accelerates rapidly, the angle counter 52 is edged before reaching the target counter value. This is when the detection unit 42 detects the edge of the crank signal, and the AD conversion by the AD conversion unit 70 cannot be executed for the number of edge-to-edge AD acquisitions, resulting in omission of the AD conversion.

In S476 and S478, the timer-dedicated processor 60 is accompanied by AD acquisition information when the edge detection unit 42 detects the edge of the crank signal and the AD conversion unit 70 performs AD conversion by the following equations (13) and (14). The storage position of the AD acquisition information is arranged so that it is stored from the character 0.

AD acquisition information (0) = AD acquisition information (n-1) ... (13)
AD acquisition information (1) = AD acquisition information (n) ... (14)
In S480, the timer-dedicated processor 60 has the subscript n set up to 1 in S476 and S478, so n = 2 and the subscript of the next AD acquisition information (n) is set.

(5) AD acquisition time interpolation process The AD acquisition time interpolation process of FIG. 6 is executed in S472 of FIG.
In S490, the timer-dedicated processor 60 calculates the acceleration represented by a in the equation (15) based on the following equations (15) to (18).

v = v0 + at ... (15)
v = 1 / latest 1 count time ... (16)
v0 = 1 / Last 1 count time ... (17)
Execution time of t = AD conversion ... (18)
In S492, the timer-dedicated processor 60 substitutes the acceleration indicated by a calculated in S490 and v0 represented by the equation (17) into the following equation (19), and expresses the relationship between x and t by the quadratic equation.

^{x = v0t + at 2/2} ··· (19)
In equation (19), x represents the counter value of the angle counter 52, and t represents the time.

In S494, the timer-dedicated processor 60 sequentially substitutes the AD acquisition counter values (0) to AD acquisition counters (n) calculated in the equation (4) into x in the equation (19), and the value of t at that time. Is calculated as the interpolation AD acquisition time (0) to the interpolation AD acquisition time (n). As a result, in FIG. 9, the interpolated AD acquisition time indicated by the black circles interpolated based on the quadratic equation of the equation (19) is set with respect to the AD acquisition time before the interpolation actually converted by the white circles. ..

(6) AD conversion omission determination process and AD conversion value interpolation process The AD conversion value interpolation process and storage process of FIG. 7 are executed in S474 of FIG.
When the determination of S500 becomes Yes, the run-up of the angle counter 52 is completed in FIG. 9, and the AD conversion by the AD conversion unit 70 shown at the timing of n = 7 is completed, the timer-dedicated processor 60 is T0 <t in S502. The AD conversion value interpolation formulas 0 (t) to m-1 (t) corresponding to the range of ≦ T1 to Tm-1 <t ≦ Tm are calculated.

Note that Tk represents the AD acquisition time (k) before interpolation, and m of m-1 (t) is executed after the edge detection unit 42 detects the edge of the crank signal last time. This is the number of times the AD conversion unit 70 has actually performed AD conversion. In FIG. 9, m = 5.

The timer-dedicated processor 60 uses the AD conversion value interpolation formulas 0 (t) to m-1 (t) from the AD conversion values before and after the AD conversion on the time axis and the AD acquisition time before interpolation, for example, in Lagrange. Calculated based on a primary interpolation formula or a secondary interpolation formula.

In S504 and S506, the timer-dedicated processor 60 sets j and k to the initial values of 0. Then, the timer-dedicated processor 60 increments k by +1 in S510 until the following equation (20) is satisfied in S508.

Tk <interpolation AD acquisition time (j) ≤ Tk + 1 ... (20)
If the determination in S508 is Yes, that is, if the interpolation AD acquisition time (j) exists within the range of the AD acquisition time before and after interpolation on the time axis, the timer dedicated processor 60 in S512 performs the AD conversion corresponding to k. The interpolation AD conversion value (j) is calculated from the value interpolation formula k (t) and the interpolation AD acquisition time (j).

The timer-dedicated processor 60 executes the processes of S504 to S512 by adding +1 to j in S516 until j reaches (number of edge-to-edge AD acquisitions + 1) in S514.
When the determination in S514 is Yes, that is, when j reaches (the number of AD acquisitions between edges + 1), the timer-dedicated processor 60 in S518 calculates the storage start address for storing the interpolated AD conversion value in the RAM 32. The storage start address is an address corresponding to the number of AD conversion values (the number of times the AD conversion unit 70 actually performs AD conversion + 1) from the address in which the latest AD conversion value actually converted to AD is stored.

In S520, the timer-dedicated processor 60 sequentially stores the interpolated AD conversion value calculated in S512 from the storage start address.
[3. effect]
In the above-described embodiment described above, the following effects can be obtained.

(1) The relationship between the counter value of the AD-converted angle counter 52 and the AD-converted time when the engine accelerates rapidly can be expressed by a quadratic equation as shown in the equation (19).
Therefore, in the above embodiment, when the AD conversion unit 70 cannot perform AD conversion because the timing of generating the crank signal has been advanced due to the rapid acceleration of the engine, AD conversion is performed every predetermined count number. The counter value of the angle counter 52 and the AD conversion time are approximated by a quadratic equation. Then, the time corresponding to the counter value of the angle counter 52 to be AD-converted is calculated as the interpolation AD acquisition time to be AD-converted.

Further, the AD conversion value in the interpolation AD acquisition time is interpolated based on the AD conversion value AD-converted by the AD conversion unit 70 before and after the interpolation AD acquisition time, and the signal cycle of the crank signal including the omission of the AD conversion is included. As the target number of AD conversions between edges, the AD conversion value of the number of edge-to-edge AD acquisitions is calculated.

As a result, even if the AD conversion that cannot be AD-converted occurs due to the sudden acceleration of the engine, the crank angle that is originally converted to AD is based on the AD conversion value that can be AD-converted, as shown by the square in FIG. At the timing of the angular position, it is possible to obtain an AD conversion value that is as close as possible to the actual AD conversion value indicated by the circle in FIG.

In the above-described embodiment, the ECU 10 corresponds to the AD conversion processing device, the angle clock generation unit 44 corresponds to the cycle shortening unit, and the timer-dedicated processor 60 corresponds to the omission determination unit, the timing setting unit, and the interpolation unit. ..
Further, the interpolation AD acquisition time corresponds to the conversion timing, the edge-to-edge AD acquisition number corresponds to the target number, the AD acquisition count number corresponds to a predetermined count number, the angle clock corresponds to the multiplication signal, and the target edge. The interpolated count corresponds to a predetermined multiplication number.

Further, S466 corresponds to the processing of the omission determination unit, the processing of S490 to S494 corresponds to the processing of the timing setting unit, and the processing of S502 to S514 corresponds to the processing of the interpolation unit.

[4. Other embodiments]
(1) In the above embodiment, it is determined whether or not the AD conversion is omitted by comparing the actual AD acquisition interval time with the time required for the AD conversion unit 70 to perform AD conversion of the in-cylinder pressure signal. In addition to this, AD is based on whether or not the storage destination value in which the DMA unit 80 stores the AD conversion value obtained by AD-converting the in-cylinder pressure signal in the RAM 32 is out of the AD conversion value range. It may be determined whether or not a conversion omission has occurred.

In this case, it is conceivable to set a value outside the range of the AD conversion value as an initial value in advance in the storage destination of the AD conversion value.
(2) The interpolated AD conversion value is calculated by using an approximate expression that approximates the change in the in-cylinder pressure signal due to the acceleration of the engine based on the engine operating state, in addition to the Lagrange interpolation expression used in the above embodiment. You may.

(3) A plurality of functions possessed by one component in the above embodiment may be realized by a plurality of components, or one function possessed by one component may be realized by a plurality of components. .. Further, a plurality of functions possessed by the plurality of components may be realized by one component, or one function realized by the plurality of components may be realized by one component. Further, a part of the configuration of the above embodiment may be omitted. In addition, at least a part of the configuration of the above embodiment may be added or replaced with the configuration of the other above embodiment. It should be noted that all aspects included in the technical idea specified from the wording described in the claims are embodiments of the present disclosure.

(4) In addition to the AD conversion processing device described above, a system having the AD conversion processing device as a component, a program for operating a computer as the AD conversion processing device, a semiconductor memory in which this program is recorded, and the like are non-transitional. The present disclosure can also be realized in various forms such as an actual recording medium and an AD conversion processing method.

10: ECU (AD conversion processing unit), 44: Angle clock generation unit (cycle shortening unit), 52: Angle counter, 60: Timer dedicated processor (missing determination unit, timing setting unit, interpolation unit), 70: AD conversion unit

Claims (5)

An angle at which the multiplication factor is counted during the signal cycle in synchronization with the multiplication signal of the cycle obtained by dividing the signal cycle of the crank signal generated at a predetermined angular interval with the rotation of the crankshaft of the engine by a predetermined multiplication factor. Counter (52) and
The detection signal of the sensor that detects the operating state of the engine is AD-converted for the target number of times during the signal cycle, and the detection signal is AD-converted every time the angle counter counts a predetermined count number. AD conversion unit (70)
When the crank signal is detected, it is determined whether or not the AD conversion omission that the AD conversion unit cannot perform AD conversion has occurred during the signal cycle because the generation timing of the crank signal has been advanced due to the acceleration of the engine. The omission determination unit (60, S466) configured in
When the omission determination unit determines that the AD conversion omission has occurred, the AD conversion unit sets the target number of times and the conversion timing to be AD-converted in synchronization with the angular position of the crankshaft during the signal cycle. Timing setting units (60, S490-S494) configured to do so,
An interpolation unit (60, S502 to S514) configured to interpolate the AD conversion value at the conversion timing set by the timing setting unit based on the AD conversion value obtained by the AD conversion unit.
AD conversion processing apparatus. The AD conversion processing apparatus according to claim 1.
The interpolation unit is configured to interpolate the AD conversion value at the conversion timing based on the AD conversion value that the AD conversion unit has AD-converted at the timing before and after the conversion timing is sandwiched.
AD conversion processing device. The AD conversion processing apparatus according to claim 1 or 2.
If the crank signal is generated before the angle counter counts the multiplication number, a cycle shortening unit (44) configured to shorten the cycle of the multiplication signal until the angle counter counts the multiplication number is provided. Further prepare
The omission determination unit compares the time between the timings at which the AD conversion unit synchronizes with the multiplication signal to perform AD conversion with the conversion time required for the AD conversion unit to perform AD conversion, and performs the AD conversion. It is configured to determine whether or not an omission has occurred.
AD conversion processing device. The AD conversion processing apparatus according to any one of claims 1 to 3.
The timing setting unit is configured to set the conversion timing based on the acceleration accelerated by the engine.
AD conversion processing device. The AD conversion processing apparatus according to claim 4.
Based on the acceleration, the timing setting unit expresses the relationship between the time and the counter value of the angle counter by a quadratic expression, and the counter value of the angle counter when the predetermined count number is counted is the counter value of the angle counter. It is configured to set the time obtained by substituting into the following equation as the conversion timing.
AD conversion processing device.

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