JP5799891B2 - AD conversion processor - Google Patents

Description

  The present invention relates to an AD conversion processing device that detects an abnormality as a result of AD conversion of an output signal of an in-cylinder pressure sensor in synchronization with a crank angle represented by a multiplied signal of a crank angle signal.

  Conventionally, for example, when the engine is supercharged, the temperature in the cylinder excessively increases, and preignition may occur in which the air-fuel mixture abnormally ignites at a timing advanced from the ignition timing when ignition is performed by the spark plug.

  Since the engine control device controls fuel injection and ignition timing based on a crank angle signal generated at predetermined angular intervals as the engine rotates, pre-ignition occurs to prevent pre-ignition from occurring. It is conceivable to detect the crank angle and control the fuel injection and ignition timing based on the detected crank angle.

  The crank angle at which abnormal combustion such as pre-ignition occurs is AD-converted from the output signal of the in-cylinder pressure sensor that detects the pressure in the cylinder (in-cylinder pressure), and the change in the in-cylinder pressure indicated by the AD conversion data This can be detected by analyzing the combustion state in the cylinder based on the above.

  As a configuration for improving the detection accuracy of the crank angle at which abnormal combustion occurs, it is conceivable to reduce the angle interval at which the crank angle signal is generated. As a configuration for improving the detection accuracy without reducing the angular interval of the crank angle signal, as described in Patent Document 1, a multiplied signal having a period obtained by dividing the signal period of the crank angle signal by the multiplication number is generated. It is known.

JP 2005-133614 A

  When the crank angle signal is generated, the multiplication signal is generated as a signal with a period obtained by dividing the period of the crank angle signal of the previous time and this time by the multiplication number. The next crank angle signal may be generated before the multiplication signal of the multiplication number is generated between the angle signals. Then, AD conversion is not executed in a part of the crank angle indicated by the multiplied signal between the current and next crank angle signals, and the output is lost.

  Also, if the AD conversion time at the timing of the current multiplied signal becomes longer for some reason and the next multiplied signal is generated during the AD conversion, the AD converted data in the current multiplied signal becomes the AD converted data in the next multiplied signal. Will be overwritten from the middle.

  As described above, when the AD conversion data is lost or a part of the AD conversion data is overwritten, the correspondence between the crank angle represented by the multiplied signal and the AD conversion data is lost. A technique for detecting such an abnormality in the AD conversion result has not been known.

  Therefore, since the presence / absence of abnormal combustion such as pre-ignition is determined based on AD conversion data that does not correspond to the crank angle, there is a possibility that the presence / absence of abnormal combustion may be erroneously determined. As a result, erroneous injection control and ignition timing control may be executed based on AD conversion data representing in-cylinder pressure.

  The present invention has been made to solve the above-described problems, and provides an AD conversion processing apparatus that detects an abnormality as a result of AD conversion of an output signal of an in-cylinder pressure sensor in synchronization with a crank angle represented by a multiplied signal. For the purpose.

  According to the AD conversion processing apparatus of the present invention, the output of the in-cylinder pressure sensor for detecting the pressure in the cylinder of the internal combustion engine in synchronization with the crank angle represented by the multiplied signal of the period obtained by dividing the signal period of the crank angle signal by the multiplication number. The signal is AD converted, and the AD conversion data is stored in the conversion data area of the storage device.

  Then, AD conversion data at the crank angle is not stored in the conversion data area, or a part of the AD conversion data at the previous crank angle is overwritten by the AD conversion data at the subsequent crank angle at the crank angle adjacent to the front and rear. If it is determined that the crank angle does not correspond to the AD conversion data, it is determined that an abnormality in the AD conversion result in which the AD conversion data deviates from the crank angle has occurred.

  In this case, when the AD conversion data stored in the conversion data area is copied and stored in the public data area of the storage device, an abnormal value indicating an abnormality is indicated at the corresponding storage position of the public data area in which the AD conversion data is stored. Set and notify AD conversion abnormality.

  Thereby, the process of referring to the AD conversion data determines, for example, whether the AD conversion data is abnormal based on the value of the AD conversion data in the public data area. Appropriate measures such as interrupting the abnormality determination process if it is an abnormal value or interpolating the AD conversion data at the crank angle corresponding to the abnormal value with the normal AD conversion data at the front and rear crank angles. Can be executed. As a result, it is possible to prevent erroneous determination of the presence or absence of abnormal combustion based on abnormal AD conversion data.

  In addition, according to the AD conversion processing apparatus of the present invention, the crank angle when the output signal of the in-cylinder pressure sensor is AD-converted in synchronization with the crank angle represented by the multiplication signal is stored in the crank angle region, so that it is stored in the crank angle region. When there is a missing crank angle, it can be easily determined that AD conversion data at the missing crank angle is not stored in the converted data area.

  Here, the data length of the result of AD conversion of the output signal of the in-cylinder pressure sensor at each crank angle is the same. Therefore, when AD conversion data is stored in the conversion data area in the order of the crank angle, a part of the AD conversion data at the previous crank angle is overwritten by the AD conversion data at the subsequent crank angle at the crank angles adjacent to each other. It can be determined whether or not the storage position for storing AD conversion data at the subsequent crank angle is a position overlapping the AD conversion data at the previous crank angle.

  Therefore, according to the AD conversion processing device of the present invention, the AD conversion data is stored in the conversion data area in the order of the crank angle, and the storage position where the AD conversion data at each crank angle is stored in the conversion data area is the storage position of the storage device. Since it is stored in the area, a part of the AD conversion data at the previous crank angle is overwritten by the AD conversion data at the subsequent crank angle at the crank angles adjacent to each other on the basis of the storage position stored in the storage position area. It can be easily determined whether or not.

  The functions of the plurality of means provided in the present invention are realized by hardware resources whose functions are specified by the configuration itself, hardware resources whose functions are specified by a program, or a combination thereof. The functions of the plurality of means are not limited to those realized by hardware resources that are physically independent of each other.

The block diagram which shows the engine control system by this embodiment. The time chart which shows a crank angle signal. Explanatory drawing which shows missing of AD conversion. Explanatory drawing which shows the overwriting of AD conversion data. The time chart explaining acceleration determination. The flowchart which shows a process at the time of starting. The flowchart which shows an angle synchronous process. The flowchart which shows a data check process. The flowchart which shows a public data initialization process. The flowchart which shows an acceleration determination process. 6 is a flowchart showing data copy processing. Map showing data copy destination. The block diagram explaining the storage area of the data relevant to AD conversion.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The engine control system 2 shown in FIG. 1 is a system that controls the operating state of a gasoline engine, for example. The engine control system 2 includes an electronic control unit (ECU) 10 for engine control, a fuel injection valve 60, a spark plug 62, a rotational speed (NE) sensor 64, an in-cylinder pressure sensor (CPS) 66, and the like. ing.

  The engine ECU 10 includes microcomputers (hereinafter also referred to as microcomputers) 20 and 40 and an input / output circuit 50. The microcomputer 20 includes a CPU 22, a ROM 24, a RAM 26, a hard crank 28, a timer 30, and an AD converter (ADC) 32. The microcomputer 40 has substantially the same configuration as the microcomputer 20.

  The microcomputers 20 and 40 execute the control programs stored in the respective ROMs 24 to input the output signals of the NE sensor 64, the CPS 66, and other sensors (not shown) via the input / output circuit 50, and communicate with each other. However, engine control such as the injection timing of the fuel injection valve 60 and the ignition timing of the spark plug 62 is executed based on the multiplication signal generated by the hard crank 28.

  As shown in FIG. 2, the hard crank 28 of the microcomputer 20 is a circuit unit that hard-processes a crank angle signal (NE signal) that is input at a predetermined angular interval, for example, a 10 ° CA period as the crankshaft rotates. It is. The NE signal is provided with a missing tooth portion for two teeth (for 30 ° CA) used for cylinder discrimination at one location at 360 ° CA.

  The hard crank 28 measures the time interval between the previous and current NE signals generated at a 10 ° CA cycle with a counter or the like synchronized with the clock, and uses the multiplication number n for the measured time interval every time the NE signal rises. 1 / n to generate a multiplied signal. In the present embodiment, the multiplication number is 2, and a multiplication signal having a 5 ° CA period is generated.

  The ADC 32 AD converts the output signal indicating the in-cylinder pressure from the CPS 66 installed in each cylinder in synchronization with the rising edge of the multiplied signal. At this time, the data obtained by AD-converting the output signal of the CPS 66 as it is and the data AD-converted after the output signal of the CPS 66 is amplified are sequentially written from the ADC 32 to a predetermined area of the RAM 26 by DMA transfer.

  In this embodiment, the data obtained by AD conversion of the output signal of the CPS 66 and the amplified data are each 2 bytes. Therefore, 4-byte data for one cylinder and 16-byte data for 4 cylinders become AD conversion data at a crank angle represented by a multiplication signal.

Based on the in-cylinder pressure AD-converted by the ADC 32, the microcomputers 20 and 40 detect abnormal combustion such as preignition and misfire.
(A / D conversion missing)
Next, omission of AD conversion executed in synchronization with the multiplied signal will be described. As described above, the multiplied signal measures the time interval of the 10 ° CA NE signal between the previous time and the current time, and generates a multiplied signal with a 5 ° CA period until the next NE signal. In the present embodiment, the ADC 32 AD-converts the output signal of the CPS 66 in synchronization with the crank angle indicated by the 5 ° CA cycle multiplied signal. The RAM 26 stores AD conversion data, a crank angle at which AD conversion is executed, a conversion time when AD conversion is executed in synchronization with the multiplied signal, and a storage address for storing AD conversion data at each crank angle. To remember.

  In FIG. 3, a multiplied signal between 120 ° CA and 150 ° CA is generated based on a time interval between 110 ° CA and 120 ° CA through a tooth missing portion of 30 ° CA. Therefore, when the engine rotation speed is accelerated between the toothless portions between 120 ° CA and 150 ° CA with respect to the engine rotation speed between 110 ° CA and 120 ° CA, the multiplication is equivalent to 145 ° CA. An NE signal of 150 ° CA may be generated when the signal rises and is on.

  In this case, when a NE signal of 150 ° CA is input, a multiplied signal having a period of 5 ° CA is generated from a time interval of 30 ° CA between 120 ° CA and 150 ° CA, but at 145 ° CA. Since the multiplied signal that has risen is on, the multiplied signal does not rise at 150 ° CA.

  Therefore, AD conversion is not executed at 150 ° CA, and AD conversion is executed at the rising edge of the next multiplied signal of 155 ° CA. As a result, AD conversion at 150 ° CA is lost, so AD conversion data, crank angle, conversion time, and storage address at 150 ° CA are not stored in a predetermined area of the RAM 26.

  If it is normal, the crank angle is stored in order every 5 ° CA in synchronization with the multiplication signal. Therefore, if there is a crank angle that is not stored, the AD conversion at that crank angle is missing. Easy to judge.

(Overwrite of AD conversion data)
Even if the AD conversion at the crank angle is not completely lost, part of the AD conversion data may be overwritten by the AD conversion data at the next crank angle.

  As shown in FIG. 4, when the AD conversion time in the nth multiplied signal becomes longer for some reason and the next (n + 1) th multiplied signal rises in the middle of the nth AD conversion, the ADC 32 newly becomes (n + 1). ) Since AD conversion is performed on the second multiplication signal, the nth AD conversion data is overwritten from the middle with the (n + 1) th AD conversion data.

  If the data length of AD conversion executed every 5 ° CA is normal, it is a fixed length. In this embodiment, as described above, the AD conversion data for four cylinders at the crank angle is 16 bytes. Therefore, based on the storage address indicating the storage position of the AD conversion data at the previous crank angle and the storage address of the AD conversion data at the subsequent crank angle, the AD conversion data at the previous crank angle becomes the AD at the subsequent crank angle. It can be determined whether or not the conversion data is overwritten.

  For example, in FIG. 4, the nth AD conversion data is expressed as (n + 1) th AD conversion data storage address # (n + 1) and nth AD conversion data storage address #n. It can be determined that a part is overwritten by the (n + 1) th AD conversion data. In addition, it can be seen that a portion where normal AD conversion data is not overwritten and remains.

(Acceleration judgment)
In the present embodiment, the multiplied signal is a signal generated by multiplying the period of the previous and current NE signals by (1/2) every time the NE signal is input, so that the multiplied signal having the same timing as the NE signal is generated. Represents the exact crank angle. On the other hand, crank angle timings such as 5 ° CA and 15 ° CA represented by a multiplied signal generated during an NE signal having a 10 ° CA period, such as 5 ° CA and 15 ° CA (this timing is changed to Also referred to as “multiplication timing”) is the estimated timing.

  When the engine is rotating at a constant speed, similarly to the NE signal timing, the multiplication timing also represents the exact crank angle timing, where the NE signal cycle is T0 and the multiplication signal cycle is T1. T1 = T0 / 2.

  As the engine accelerates, the period of the NE signal becomes shorter. Therefore, in the multiplied signal generated based on the period of the NE signal before acceleration, as shown in FIG. 5, the timing of the NE signal at 10 n ° CA and (10n + 5) ° The time interval T1 with the multiplication timing in CA is longer than ½ of the period T0 of the NE signal during acceleration.

  The AD conversion data acquired by AD conversion at the multiplication timing at this time is data that is AD converted at an angular position that deviates from an appropriate crank angle. As described above, if the combustion state is determined based on the AD conversion data of the in-cylinder pressure deviated from an appropriate angular position, there is a possibility that the combustion state is erroneously determined.

  Therefore, in the present embodiment, if the AD conversion data acquired at the multiplication timing is disclosed if the acceleration state is a predetermined acceleration state at the multiplication timing, “0” is set as a value that the CPS 66 cannot take.

  The acceleration determination is performed as follows, for example. As shown in FIG. 5, the period T0 of 10n ° CA and 10 (n + 1) ° CA representing the timing of the NE signal before and after the multiplication timing represented by (10n + 5) ° CA, and the NE timing of 10n ° CA ( Each time interval T1 with the multiplication timing of 10n + 5) ° CA is measured, and if the value of T0 / 2T1 is equal to or less than a predetermined value, it is determined that the vehicle is in the acceleration state at the multiplication timing of (10n + 5) ° CA.

  Next, FIGS. 6 to 11 are flowcharts of AD conversion processing executed by the microcomputer 20 in order to detect an abnormality in the AD conversion result and disclose the AD conversion data. In each flowchart, “S” represents a step.

(Processing at startup)
When the engine ECU 10 is activated, the activation process shown in FIG. 6 is executed. First, the hard crank 28 is set so that a multiplied signal with a 5 ° CA cycle can be generated from an NE signal with a 10 ° CA cycle (S400).

  Next, data for AD conversion executed every 5 ° CA in synchronization with the multiplication signal, a crank angle at that time, a conversion time for executing AD conversion, and a storage address for storing AD conversion data are stored. Settings are made (S402). For example, the start address of the data storage area is set as the write pointer.

  Then, the crank angle at which the data check is started to check whether there is any omission in the AD conversion or whether a part of the AD conversion data at the previous crank angle is overwritten with the AD conversion data at the subsequent crank angle. A check angle is set for each cylinder (S404). The data check angle is set to a predetermined crank angle that has passed the top dead center of the combustion stroke in each cylinder. For example, the first cylinder is set to 140 ° CA, the second cylinder is set to 680 ° CA, the third cylinder is set to 320 ° CA, and the fourth cylinder is set to 500 ° CA.

(Angle synchronization processing)
The angle synchronization process in FIG. 7 is executed in synchronization with the multiplied signal. The CPS 66 output signal and the signal obtained by amplifying the output signal in each cylinder are AD-converted (S410), and AD conversion data obtained as a result of the AD conversion is converted into CPS output values A and B in the conversion data area 200 shown in FIG. Is stored for each cylinder (S412).

  Furthermore, the crank angle, the conversion time, and the head storage address for storing AD conversion data when executing AD conversion are stored in the crank angle area 202, the conversion time area 204, and the storage address area 206 shown in FIG. S414, S416, S418).

(Data check process)
The data check process of FIG. 8 is executed when the data check angle set for each cylinder in S404 of FIG. 6 is reached.

  First, for the processing cylinder corresponding to the data check angle, the corresponding public data areas 210 and 212 shown in FIG. 13 are initialized. In FIG. 13, the public data areas 210 and 212 of the two surfaces are shown as the public data areas of the #n cylinder, but actually, the total of the two surfaces and the four cylinders corresponding to the CPS output values A and B for each cylinder. The eight public data areas are provided in the RAM 26. As the initial value of the public data, “0” is set as a value that cannot be taken by the output signal of the CPS 66 that detects the in-cylinder pressure (S420). The initialization process of the public data area will be described in detail with reference to FIG.

  Next, 144 is set to u1t_chkcnt and 0 is set to u1t_index as the number of AD conversions executed at a cycle of 5 ° CA at 720 ° CA corresponding to one combustion cycle (S422). u1t_index indicates the position of data stored for each 5 ° CA in synchronization with the multiplication signal in each area except the public data areas 210 and 212 shown in FIG. When 0 is set in u1t_index, the process starts from the top of the corresponding area.

  And by the process of S424-S434, the AD conversion data memorize | stored in the conversion data area | region 200 are ensured for every cylinder between the angles which complete | finish from the angle which starts acquisition of AD conversion data in each cylinder. Copy and store in the public data area.

  First, in S424, it is determined whether u1t_index is smaller than u1t_chkcnt. When u1t_index becomes equal to or greater than u1t_chkcnt (S424: No), it is determined that all AD conversion data in the conversion data area 200 has been processed, and this process is terminated.

  Next, the crank angle of the crank angle region 202 indicated by u1t_index is set to u2t_crnk (S426), and it is determined whether or not the crank angle set to u2t_crnk is within the range of the acquisition angle of the AD conversion data of the processing cylinder. (S428).

  The AD conversion data acquisition angle ranges determined by the AD conversion data acquisition start angle and acquisition end angle in each cylinder are as follows: first cylinder: 620 ° CA to 140 ° CA, second cylinder: 440 ° CA to 680 °. CA, third cylinder: 80 ° CA to 320 ° CA, and fourth cylinder: 260 ° CA to 500 ° CA.

  When the crank angle is out of the range of the AD conversion data acquisition angle (S428: No), the process proceeds to S436 without executing the processes of S430 to S434. That is, the AD conversion data of the crank angle that is not the acquisition target in the processing cylinder is skipped.

  If the crank angle is within the range of the AD conversion data acquisition angle (S428: Yes), it is determined in the acceleration determination process of S430 whether or not the engine speed has been accelerated at the timing of the current multiplied signal. The acceleration determination process will be described in detail with reference to FIG.

  In the acceleration determination process of FIG. 10, when it is determined that the engine speed has been accelerated at the timing of the current multiplied signal and the acceleration determination flag is on (S432: Yes), the data copy process of S434 is not executed, and the process proceeds to S436. Transition. In the data copy process of S434, the AD conversion data of the processing cylinder stored in the conversion data area 200 is copied to the public data area. The data copy process will be described in detail with reference to FIG.

  Accordingly, when the engine speed is accelerated at the timing of the current multiplied signal, the data copy process of S434 is not executed, and the AD conversion data at the time of acceleration remains the initial value in the public data area.

  In the acceleration determination process of FIG. 10, when it is determined that the engine speed is not accelerated at the timing of the current multiplication signal and the acceleration determination flag is off (S432: No), the data copy process of S434 is executed.

In S436, u1t_index is incremented by 1, and the process proceeds to S424. Therefore, AD conversion data stored after being AD converted at the timing of the next multiplied signal is checked.
(Public data initialization process)
FIG. 9 shows the public data initialization process executed in S420 of FIG.

  First, 0 is set to u1t_copyidx indicating the data position of the public data area of the processing cylinder (S440). Thereby, the head position of the public data area of the processing cylinder is indicated. Next, the data in the public data area of the processing cylinder is initialized by the processing of S442 to S446.

  In S442, it is determined whether or not u1t_copyidx is smaller than the number of public data entries that are AD-converted in the processing cylinder in synchronization with the multiplication signal and copied to the public data area. If u1t_copyidx is equal to or greater than the number of public data entries (S442: No), it is determined that all the public data areas of the processing cylinders have been initialized, and this process ends.

  If u1t_copyidx is smaller than the number of public data entries (S442: Yes), 0 is set as the initial value for the entry position in the public data area of the processing cylinder indicated by u1t_copyidx (S444), u1t_copyidx is incremented by 1 (S446), and S442 is entered. Migrate processing.

(Acceleration judgment processing)
FIG. 10 shows the acceleration determination process executed in S430 of FIG.
First, at this time, the crank angle of the AD conversion data copied to the public data area is not the timing of the NE signal that is a multiple of 10 ° CA, but 5 ° CA estimated by the multiplied signal between the NE signal and the NE signal. It is determined whether or not the multiplication timing is represented by 15 ° CA,... 705 ° CA, 715 ° CA.

  If it is the NE signal timing instead of the multiplication timing (S450: No), it is determined that the AD change has been executed at an appropriate crank angle position of 10 ° CA cycle, the acceleration determination flag is turned off (S452), and this process ends. To do. When the acceleration determination flag is OFF, S434 in FIG. 8 is executed, and AD conversion data at the crank angle at the corresponding multiplication timing is copied to the public data area.

If it is the multiplication timing (S450: Yes), the time interval T0 of the NE signal before and after the current multiplication timing, and the time interval T1 between the NE signal timing before the current multiplication timing and the current multiplication timing are expressed by the following equations. Calculated from (1) and (2) (S454).
T0 = conversion time [u1t_index + 1] −conversion time [u1t_index−1]
... (1)
T1 = conversion time [u1t_index] −conversion time [u1t_index−1]
... (2)
Then, it is determined whether T0 / 2T1, which is the ratio of T0 / 2 to T1, is equal to or less than a predetermined acceleration determination value (S456). The acceleration determination value is a value smaller than 1.

  When T0 / 2T1 is larger than the acceleration determination value (S456: No), it is determined that the engine is not in an acceleration state at the current multiplication timing, the process proceeds to S452, and the acceleration determination flag is set to OFF. The fact that the acceleration determination flag is OFF indicates that the AD conversion data at the current crank angle is data to be disclosed.

  If T0 / 2T1 is equal to or less than the acceleration determination value (S456: Yes), it is determined that the engine is in an acceleration state at the current multiplication timing, and the acceleration determination flag is set to ON (S458).

  The acceleration determination flag being on indicates that the AD conversion data acquired by the AD conversion at the current multiplication timing is data that deviates from an appropriate crank angle. If the combustion state is determined based on the AD conversion data of the in-cylinder pressure deviated from an appropriate crank angle, the combustion state may be erroneously determined. Therefore, when the acceleration determination flag is on, S434 in FIG. 8 is not executed, and the AD conversion data at the crank angle at the corresponding multiplication timing in the public data area remains the initial value.

(Data copy processing)
FIG. 11 shows the data copy process executed in S434 of FIG. Further, in each cylinder, the crank angle that is a target of copying the data AD-converted in a cycle of 5 ° CA in synchronization with the multiplication signal in one combustion cycle to the public data area, and the AD conversion data at the crank angle to be copied The offset position for copying in the public data area is shown in the copy destination calculation map of FIG.

  For example, the copy target angle range of the first cylinder (# 1) is 620 ° CA to 140 ° CA as described above, and the AD conversion data of 100 ° CA starts with the number 0 in the public data area of the first cylinder. Then, it is copied to the 40th offset position. U2t_crnk representing the crank angle to be copied of the processing cylinder is selected in S426 of FIG.

  First, in S460, the AD conversion data is copied from the copy destination calculation map of FIG. 12 to the public data area of the processing cylinder from the copy destination calculation map of FIG. Is set to u1t_copyidx.

  Next, the head address where the AD conversion data at the crank angle that is the current copy target in the conversion data area is stored from the storage address area 206 by u1t_index and set to u4t_copyadr, and the crank angle that is the next copy target The head address in which AD conversion data is stored is acquired from the storage address area 206 by (u1t_index + 1) and set to u4t_nextadr (S462).

  The address offset indicates in which position the CPS output values A and B of the current processing cylinder are located from the start address where AD conversion data at the crank angle to be copied is stored in the conversion data area 200. The address offsets of the CPS output values A and B of each cylinder are 0 and 2 for the first cylinder, 4 and 6 for the second cylinder, 8 and 10 for the third cylinder, and 12 and 14 for the fourth cylinder.

  Next, for the address offsets of the CPS output values A and B of the processing cylinder, it is determined whether or not u4t_copyadr + address offset is smaller than u4t_nextadr (S464).

  When the address offset of the CPS output values A and B is (u4t_copyadr + address offset) smaller than u4t_nextadr (S464: Yes), the AD conversion data corresponding to the address offset is based on the AD conversion data at the crank angle to be copied next. Judge that it has not been overwritten.

  Then, the 2-byte or 4-byte data stored in the address indicated by (u4t_copyadr + address offset) and determined not to be overwritten is copied to the offset position indicated by u1t_copyidx in the public data area.

  If (u4t_copyadr + address offset) is greater than or equal to u4t_nextadr, that is, the storage address of the CPS output value A or CPS output value B of the processing cylinder is greater than or equal to the first storage address of the AD conversion data at the next crank angle (S464: No) It is determined that the AD conversion data is overwritten by the AD conversion data at the next crank angle.

  In this case, since the overwritten AD conversion data cannot be copied, this processing is terminated. That is, the initial value is set in the AD conversion data of the corresponding processing cylinder in the public data area. This initial value is set to “0”, which is a value that cannot be obtained as the output of the CPS 66 by the abnormality detection process described above.

  As described above, when the in-cylinder pressure public data copied to the public data area by the AD conversion process is referred to by other processes other than the AD conversion process, for example, the abnormal combustion determination process, it is understood that the initial value is obtained. Appropriate processing such as interrupting the abnormality determination or interpolating AD conversion data at the crank angle corresponding to the abnormal value with normal AD conversion data at the preceding and succeeding crank angles can be executed. As a result, it is possible to prevent erroneous determination of the presence or absence of abnormal combustion based on abnormal AD conversion data.

[Other Embodiments]
In the above embodiment, both the missing AD conversion and the missing AD conversion data at the previous crank angle are overwritten by the AD conversion data at the subsequent crank angle at the crank angles adjacent to the front and rear. If it is overwritten, the data of the corresponding crank angle in the public data area is set, and if it is overwritten, an abnormal value that is not possible as AD conversion data of the output signal of the CPS 66 is set in the overwritten portion of the crank angle. .

On the other hand, according to the present invention, an abnormal value may be set in the corresponding part of the public data area only in one of the case where it is missing or overwritten.
If overwritten, the crank angle data including the non-overwritten portion may be set to an abnormal value.

  In the above embodiment, the functions of the storage unit, result determination unit, setting unit, and acceleration determination unit are realized by the engine ECU 10 whose functions are specified by the control program. On the other hand, at least some of the functions of the plurality of means may be realized by hardware whose functions are specified by the circuit configuration itself.

  As described above, the present invention is not limited to the above-described embodiment, and can be applied to various embodiments without departing from the gist thereof.

10: Engine ECU (AD conversion processing device), 20: Microcomputer (AD conversion means, storage means, result determination means, setting means, acceleration determination means), 26: RAM (storage device), 32: ADC (AD conversion means) , 200: Conversion data area, 202: Crank angle area, 204: Conversion time area, 206: Storage address area (storage position area), 210, 212: Public data area

Claims (5)

The pressure in the cylinder of the internal combustion engine is detected in synchronization with a crank angle represented by a multiplication signal of a cycle obtained by dividing a signal cycle of a crank angle signal generated at a predetermined angular interval with rotation of the crankshaft of the engine by a multiplication number. AD conversion means (32, S410) for AD converting the output signal of the in-cylinder pressure sensor;
Storage means (20, S412) for storing the AD conversion data by the AD conversion means in the conversion data area (200) of the storage device (26);
Whether or not the AD conversion data at each crank angle is stored in the conversion data area, or a part of the AD conversion data at the previous crank angle at the crank angle adjacent to the front and rear is at the subsequent crank angle A result determination means (20, S434) for determining whether or not the data is overwritten by the AD conversion data;
When the result determination means determines that the AD conversion data is not stored or a part of the AD conversion data is overwritten, the AD conversion data stored in the conversion data area is When storing in the public data area (210, 212) of the storage device, an abnormal value indicating abnormality is set in the corresponding storage position of the public data area in which the AD conversion data that is not stored or overwritten is stored. Setting means (20, S420, S440 to S446);
An AD conversion processing device comprising: The storage means (20, S414) stores the crank angle when the AD conversion means AD converts the output signal of the in-cylinder pressure sensor in a crank angle region (202) of the storage device,
The result determination means (20, S460) stores the AD conversion data at the crank angle at which the missing angle is stored in the converted data area when the crank angle stored in the crank angle area is missing. Judge that it is not,
The AD conversion processing apparatus according to claim 1. The storage means (20, S418) stores the AD conversion data in the conversion data area in the order of the crank angle, and stores the storage position for storing the AD conversion data at each crank angle in the conversion data area. Stored in the storage location area (206) of the device,
Based on the storage position stored in the storage position area, the result determination means (20, S464) determines that a part of the AD conversion data at the previous crank angle in the adjacent crank angle is rearward. Determining whether or not it is overwritten by the AD conversion data at the crank angle of
The AD conversion processing apparatus according to claim 1 or 2, characterized in that The setting means (20, S464, S466) overwrites the corresponding AD conversion data when storing the AD conversion data determined to be partially overwritten by the result determination means in the public data area. The data that has not been stored is stored as it is, and the abnormal value is set in the overwritten portion.
The AD conversion processing apparatus according to claim 3. The storage means (20, S416) stores a conversion time at which the AD conversion means executes AD conversion in synchronization with the crank angle in a conversion time area (204) of the storage device,
When the AD conversion data stored in the conversion data area is stored in the public data area, the engine between the crank angles adjacent to each other is based on the conversion time stored in the conversion time area. Accelerating determination means (20, S430, S450 to S458) for determining whether or not the acceleration at which the rotation speed acceleration is equal to or greater than a predetermined value has been performed;
The setting means (20, S432), when the acceleration determination means determines that the acceleration of the predetermined value or more has been performed, the corresponding storage position of the public data area for storing the AD conversion data when the acceleration is started Set the abnormal value to
The AD conversion processing apparatus according to any one of claims 1 to 4, wherein

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