JP6499987B2 - Engine control device - Google Patents

Description

  The present invention relates to an engine control device including a knocking detection control device that determines the occurrence of knocking from vibrations generated by abnormal combustion of an internal combustion engine.

  As is well known, the knocking phenomenon that occurs in the engine is a phenomenon in which the gas in the combustion chamber vibrates due to the self-ignition of unburned gas in the end portion of the engine combustion chamber, and this vibration is transmitted to the engine body. It is desirable to avoid the knocking phenomenon as much as possible because it causes damage to engine components due to impacts on various parts of the engine and the driver feels uncomfortable due to the generation of impact sounds. It is essential to detect.

  Japanese Patent Application Laid-Open No. 56-000637 has a knock detector for detecting vibrations generated in an internal combustion engine and a plurality of filters connected to the knock detector and having filter characteristics in different frequency bands in the knocking frequency band. A filter circuit and a knocking detection device that selects a predetermined output among the filter circuits according to the engine state are disclosed.

  The frequency band of knocking occurring in the internal combustion engine varies depending on the operating state of the internal combustion engine. For example, since the frequency band of knocking differs depending on whether the rotational speed of the internal combustion engine is high or low, a plurality of filter circuits having filter characteristics of different frequency bands are provided for these knocking frequency bands, and the internal combustion engine If the filter circuit output is selected according to the operating state of the engine, it is possible to detect knocking with high reliability.

  In recent years, it is also known that the filter circuit is realized by a digital filter by software installed in a microcomputer, and further, a method of configuring a digital filter as a function of the microcomputer is also known.

JP-A-56-000637

  According to the knock detection device for an internal combustion engine according to Patent Document 1 described above, a filter circuit having a plurality of filters having filter characteristics in different frequency bands in the knocking frequency band, and among the filter circuits according to the engine state, By selecting a predetermined output, the reliability of knock detection can be improved.

  However, it is necessary to provide a filter circuit corresponding to the state of the internal combustion engine in advance, which increases the number of circuits and increases the cost.

  Therefore, there is known a method of reducing the cost by suppressing the increase in the number of filter circuits by realizing the plurality of filter circuits with a plurality of digital filters implemented by software mounted on a microcomputer. However, as the frequency band to be filtered increases. There is a problem that the number of digital filters increases and the CPU calculation load of the microcomputer increases.

  Further, a method of reducing the CPU calculation load by configuring a digital filter using a plurality of filter circuits as functions of a microcomputer is known. However, since the number of digital filters depends on the specifications of the microcomputer, the filter When the frequency band to be increased increases, there is a problem that the number of digital filters is insufficient.

  In addition, when the plurality of filters are selected according to the state of the internal combustion engine, the output of the filter is not stable immediately after the filter is switched, so that there is a problem that the accuracy of knocking detection is deteriorated immediately after the filter is switched.

  The present invention has been made to solve such a problem, and its technical problem is that in an internal combustion engine control device that detects knocking by switching a plurality of filters, an increase in CPU calculation load caused by software, Another object of the present invention is to provide an engine control device that suppresses the shortage of a digital filter mounted on a microcomputer and prevents deterioration in the accuracy of knock detection at the time of filter switching.

  In order to achieve the above object, the present invention has a combustion state detection device that detects a combustion state of an internal combustion engine, has a filter function that can extract abnormal combustion, and switches the operation of the filter function in an operation region. In the detection apparatus, an engine control device is provided that operates a filter at a switching destination before switching an active filter.

  In the abnormal combustion detection device having a combustion state detection device for detecting the combustion state of the internal combustion engine, having a filter function capable of extracting abnormal combustion, and switching the operation of the filter function in the operation region, by switching a plurality of filters, Suppressing the increase in CPU computation load caused by software and the shortage of digital filters mounted on the microcomputer, and preventing the deterioration of knocking detection accuracy at the time of filter switching by operating the filter at the switching destination in advance before switching the filter An engine control device can be provided. Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

1 is a system configuration diagram of engine control according to an embodiment of the present invention. FIG. It is a block diagram of the control unit by one Embodiment of this invention. It is a flowchart which shows the control structure of this invention. It is a flowchart which shows the target filter calculation of this invention. It is a target filter setting map of the present invention. It is a flowchart which shows the standby filter calculation of this invention. It is a flowchart which shows the active filter calculation of this invention. It is an active filter setting map of the present invention. It is a flowchart which shows the filter A calculation of this invention. It is a flowchart which shows the filter B calculation of this invention. It is a flowchart which shows the filter calculation for knock detection of this invention. It is a time chart of filter setting by a first embodiment. It is a flowchart which shows the standby filter calculation by 2nd embodiment of this invention. It is a time chart of filter setting by a second embodiment.

  Embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments, and various modifications and application examples are included in the technical concept of the present invention. It is included in the range.

  First, a first configuration of a control system for an internal combustion engine to which the present invention is applied will be described with reference to FIGS. Here, although the embodiment shown in FIG. 1 shows a so-called port injection type four-cylinder internal combustion engine, an in-cylinder direct injection type engine may be used and can be applied regardless of the number of cylinders.

  FIG. 1 is a configuration diagram of an internal combustion engine control system according to a first configuration.

  The air sucked into the internal combustion engine 65 passes through the air cleaner 60 and is guided to the hot wire type air flow sensor 2. A hot wire air flow sensor is used as the hot wire air flow sensor 2. The hot wire airflow sensor 2 outputs a signal corresponding to the intake air amount, and outputs an intake air temperature signal measured by an intake air temperature sensor 2a using a thermistor. Next, the intake air enters the collector 62 through the connected duct 61 and the throttle valve 40 for controlling the air flow rate. The throttle valve is moved by a throttle drive motor 42 driven by a control unit 71. The air that has entered the collector 62 is distributed to each intake pipe directly connected to the engine, and is taken into the cylinder. The valve drive system has a variable valve timing mechanism that performs feedback control toward the target angle. Further, a pulse is output from the crank angle sensor 7 attached to the cylinder block at every predetermined crank angle, and these outputs are input to the control unit 71. The vibration detection sensor 4 attached to the cylinder block converts the vibration generated in the internal combustion engine into a voltage and outputs the voltage, and these outputs are input to the control unit 71. The vibration detection sensor 4 may be common to all cylinders, may be provided for each cylinder, may be provided for each cylinder grouped in advance, or may be a single or a plurality.

  The fuel is sucked and pressurized from the fuel tank 21 by the fuel pump 20, adjusted to a constant pressure by the pressure regulator 22, and injected from the injector 23 provided in the intake pipe into the intake pipe.

  A throttle sensor 1 for detecting the opening of the throttle valve is attached to the throttle valve 40. This sensor signal is input to the control unit 71, and feedback control of the opening of the throttle valve 40, detection of the fully closed position, Detect acceleration etc. The target opening for feedback is obtained from the accelerator depression amount of the driver obtained by the accelerator opening sensor 14 and the idle speed control, that is, the ISC control.

  A water temperature sensor 3 for detecting the cooling water temperature is attached to the internal combustion engine 65, and this sensor signal is input to the control unit 71 to detect the warm-up state of the internal combustion engine 65 and increase the fuel injection amount. Further, the ignition timing is corrected, the radiator fan 75 is turned on / off, and the target rotational speed at idling is set. In addition, an air conditioner switch 18 for monitoring the condition of the air conditioner clutch and a neutral switch 17 built in the transmission for monitoring the condition of the drive system are attached in order to calculate the target rotational speed at idle and the load correction amount. Yes.

  The air-fuel ratio sensor 8 is attached to the exhaust pipe of the engine and outputs a signal corresponding to the oxygen concentration of the exhaust gas. This signal is input to the control unit 71, and the fuel injection pulse width is adjusted so that the target air-fuel ratio obtained in accordance with the driving situation is obtained.

  The ignition coil 30 is provided with a coil and connected to the control unit 71. An ignition signal and a timing signal are input in accordance with the energization time and ignition timing of the coil calculated by the control unit 71, and spark discharge of the spark plug 33 is performed by discharge by the coil.

  Next, input / output signals of the automobile control unit 71 according to the present embodiment will be described with reference to FIG.

As shown in FIG. 2, the control unit 71 includes a CPU 78 and a power supply IC 79. Here, when the signals and the like input to the control unit 71 are organized using the same figure, the air flow sensor and the built-in intake air temperature sensor 2a, the crank angle sensor 7, the throttle sensor 1, the water temperature sensor 3, the oil temperature sensor 25, the accelerator A signal from the opening sensor 14 is input. The vibration detection sensor inputs to the filter A 101 and the filter 102 B, and the outputs of the filter A 101 and the filter 102 B are input to the CPU 78. The filter A 101 and the filter B 102 can set arbitrary frequency bands by the CPU 78, and can extract the frequency bands set by the CPU 78.
An output signal from the control unit 71 is output to the injector 23, the fuel pump 20, the ignition coil 30, and the throttle drive motor 42.

  Next, specific control contents by the automobile control apparatus according to the present embodiment will be described with reference to FIGS.

  First, the outline of the control contents of the engine control apparatus according to the present embodiment will be described with reference to FIG.

  FIG. 3 is a flowchart showing an outline of control contents of the knock detection filter of the engine control apparatus according to the embodiment of the present invention.

  The control flow of FIG. 3 includes step 3110 (target filter calculation), step 3120 (standby filter calculation), step 3130 (determination during active filter), step 3140 (filter A setting), and step 3150 (filter B setting). ) And step 3160 (knock detection filter setting).

  The contents of FIG. 3 are programmed in the CPU 78 of the control unit 71 and repeatedly executed at a predetermined cycle. For example, it is executed as interruption processing by a predetermined angle synchronized with the crank angle or a time timer converted into an angle. That is, the processing of the following steps 3110 to 3160 is executed by the control unit 71.

  Step 3110 is a target filter calculation process for extracting the knocking frequency. The filter frequency is set according to the engine operating condition.

  Step 3120 is a standby filter calculation process for preventing a response delay at the time of filter switching by setting a filter in advance and operating it in preparation for a case where the knocking frequency changes due to a change in the engine operating state. From the state, the knocking frequency change is estimated, and the standby filter frequency is set.

  Step 3130 is an active filter determination step for determining whether the filter A or the filter B detects knocking. Filter A or filter B is selected according to the calculation result of the target filter.

  Step 3140 is a filter A setting step for setting a frequency to be extracted to the filter A. Either the target filter or the standby filter is set according to the result of the active filter determination.

  Step 3150 is a filter B setting process for setting the frequency to be extracted to the filter B. Either the target filter or the standby filter is set according to the result of the active filter determination.

  Step 3060 is a knock detection filter setting step for setting a filter for extracting knocking. Depending on the active filter, either filter A or filter B is set as a knock detection filter.

  Next, details of the target filter calculation in step 3110 of FIG. 3 will be described with reference to FIG.

  Step 4110 is an operation area acquisition process. The engine operating range is determined from the engine speed and load.

  Step 4120 is a target filter setting process. Based on the operation region acquired in step 4110, a filter setting capable of extracting the knocking frequency is calculated. Here, the filter setting may be any of a high-pass filter, a low-pass filter, and a band-pass filter. In the case of a high-pass filter and a low-pass filter, a filter cutoff frequency is set, and in the case of a band-pass filter, the center frequency of the filter. Alternatively, a cutoff frequency may be set. The set value of the filter may be calculated by calculation, or may be set by searching a setting map based on the engine speed and load shown in FIG. Here, it is desirable to provide hysteresis (broken line and solid line in FIG. 5) at the boundary between the engine speed and the frequency due to the load. When the engine speed or the load increases, F1 and F2 each time the solid line is exceeded. , F3, and when the engine speed or load decreases, it switches to F3, F2, F1 every time the broken line is exceeded. In FIG. 5, the knocking frequencies set in the filter are indicated as F1, F2, and F3.

  In FIG. 5, the setting is made according to the engine speed and the load. However, the setting may be made according to the calculation load of the CPU. For example, the calculation load can be reduced in a region where the calculation load becomes high due to high rotation or the like. It is desirable to set a filter.

  In step 4130, the search result in step 4120 is set as a target filter.

  In this embodiment, the target filter is described as having a configuration in which one frequency band is set, but there may be a plurality of target filters. Further, in FIG. 5, the filter is described in three stages, but it may be four or more stages depending on the degree of change in the knocking frequency.

  In FIG. 5, the target filter is switched twice in the operation region, but the number of times of switching is preferably set according to the number of frequencies to be detected and the number of operable filters.

  Next, details of the standby filter calculation in step 3120 of FIG. 3 will be described with reference to FIG.

  Step 6110 is a target filter acquisition process, in which the target filter set in FIG. 4 is acquired.

  Step 6120 is a step of determining whether or not the target filter is F1 shown in FIG. If it is F1, the process proceeds to step 6130. If not, the process proceeds to step 6170.

  Step 6130 is a process of determining whether or not the engine speed is smaller than the F1 determination value L. When it is smaller than the F1 determination value L, the routine proceeds to step 6140, where F1 is set to the standby filter. If NO, go to Step 6150. In step 6140, F1 is set in the standby filter, but it may be stopped. In this way, power consumption can be reduced when the filter is realized by hardware, and calculation load can be reduced when the filter is realized by software.

  Step 6150 is a determination process for determining whether or not the engine speed is larger than the F1 determination value H. When it is larger than the F1 determination value H, the routine proceeds to step 6160, where F2 is set to the standby filter. If not, the process ends without updating the standby filter setting (previous value retention).

  Step 6170 is a process of determining whether or not the target filter is F2 shown in FIG. If it is F2, the process proceeds to step 6180. If not, the process proceeds to step 6230.

  Step 6180 is a process of determining whether or not the engine speed is smaller than the F2 determination value L. When it is smaller than the F2 determination value L, the routine proceeds to step 6190, where F2 is set to the standby filter. If NO, go to step 6210.

  Step 6210 is a process of determining whether or not the engine speed is greater than the F2 determination value H. When it is larger than the F2 determination value H, the routine proceeds to step 6220, where F3 is set to the standby filter. If not, the process ends without updating the standby filter setting (previous value retention).

  Step 6230 is a process of determining whether or not the engine speed is smaller than the F3 determination value L. When it is smaller than the F3 determination value L, the routine proceeds to step 6240, where F2 is set in the standby filter. If NO, go to Step 6250.

  Step 6250 is a determination process for determining whether or not the engine speed is larger than the F3 determination value H. When it is larger than the F3 determination value H, the routine proceeds to step 6260, where F3 is set in the standby filter. If not, the process ends without updating the standby filter setting (previous value retention). In step 6160, F3 is set in the standby filter, but it may be stopped. In this way, power consumption can be reduced when the filter is realized by hardware, and calculation load can be reduced when the filter is realized by software.

  Note that the F1 determination value L, the F1 determination value H, the F2 determination value L, the F2 determination value H, the F3 determination value L, and the F3 determination value H are desirably set in consideration of switching of the target filter, preferably It is desirable to set the standby filter to a desired filter before the target filter is switched. Therefore, it is desirable to correct each determination value with the acceleration of the load or the engine speed. In particular, when the engine acceleration is large, the target filter changes faster, so it is desirable to set a filter at a lower speed and a higher speed. When the engine acceleration is negative, that is, when the engine is decelerating, the target filter is higher. It is desirable to set a filter on the low rotation side for rotation.

  Next, details of the active filter determination in step 3130 of FIG. 3 will be described with reference to FIG.

  Step 7110 is a target filter acquisition process. The target filter set in FIG. 4 is acquired.

  Step 7120 is an active filter search process, in which a filter used for knocking detection is calculated by searching a preset table as shown in FIG. For example, when the target filter set from FIG. 4 is F1, the filter A is set as the active filter from the table of FIG.

  In this embodiment, the target filter is described as having a configuration in which one frequency band is set, but there may be a plurality of target filters. In that case, a plurality of active filters are set.

  Step 7130 is an active filter setting process, and an active filter is set based on the search result of step 7120.

  Next, details of the filter A setting in step 3140 in FIG. 3 will be described with reference to FIG.

  Step 9110 is an active filter acquisition process. The active filter set in FIG. 8 is acquired.

  Step 9120 is a process of determining whether or not the active filter is the filter A. If the active filter is filter A, the process proceeds to step 9130, and the target filter set in FIG. If not, the process proceeds to step 9140, and the standby filter set in FIG.

  Next, details of the filter B setting in step 3150 of FIG. 3 will be described with reference to FIG.

  Step 10110 is an active filter acquisition process. The active filter set in FIG. 8 is acquired.

  Step 10120 is a process of determining whether or not the active filter is the filter B. If the active filter is filter B, the process proceeds to step 10130, and the target filter set in FIG. If not, the process proceeds to step 10140, and the standby filter set in FIG.

  Next, details of the knock detection filter setting in step 3160 of FIG. 3 will be described with reference to FIG.

  Step 11110 is an active filter acquisition process. The active filter set in FIG. 8 is acquired.

  Step 11120 is a process of determining whether or not the active filter is the filter A. When the active filter is the filter A, the process proceeds to step 11130, and the filter A is set as the knock detection filter in step 11130. If not, the process proceeds to step 11140, and the filter B is set as the knock detection filter. The knocking frequency is extracted using the knock detection filter set here.

  Next, the operation of the control apparatus for an internal combustion engine according to the present embodiment will be described with reference to FIG.

  FIG. 12 is a time chart showing an operation example of the control device for the internal combustion engine according to the embodiment of the present invention.

  The example of FIG. 12 shows an operation in which the filter A and the filter B are switched while the engine speed is increased, and the knock detection filter used for extracting the knock frequency is finally switched.

  Before time t1 in FIG. 12, since the engine speed is low and the target filter is set to F1, the active filter is filter A, F1 is set to filter A, and the knock detection filter is F1. The standby filter is stopped in order to reduce power consumption or calculation load.

  When the engine speed becomes equal to or higher than the F1 determination value H at time t1 in FIG. 12, the standby filter is set to F2, and F2 is set to the filter B. Since the target filter is F1, the knock detection filter remains F1.

  When the target filter is switched to F2 at time t2 in FIG. 12, filter B is set as the active filter, and filter 2 is used as the knock detection filter. Since F2 is preset in the filter 2 at time t1, the filter can be switched without delay at time t2. That is, the filter can be switched without delay by starting and operating the F2 filter in advance in anticipation of an increase in the engine speed.

  When the engine speed reaches F2 determination value H or more at time t3 in FIG. 12, the standby filter is set to F3, and F3 is set to filter A. Since the target filter is F2, the knock detection filter remains F2.

  When the target filter is switched to F3 at time t4 in FIG. 12, filter A is set as the active filter, and filter 1 is used as a knock detection filter. Since F3 is preset in the filter 1 at time t3, the filter can be switched without delay at time t4. That is, the filter can be switched without delay by starting the F3 filter in advance in anticipation of an increase in the engine speed.

  When the engine speed becomes equal to or higher than the F3 determination value H at time t5 in FIG. 12, the standby filter is set to stop, the stop is set to filter B, and power consumption or calculation load is reduced. Since the target filter is F3, the knock detection filter remains F3.

  With the above configuration, it is possible to extract all knocking frequencies when the knocking frequency extracted for each operation region is different and the number of operable filters is smaller than the number of knocking frequencies to be detected. In addition, by suppressing the shortage of the number of filters and starting the filters in advance for changes in the operation region, it is possible to prevent instability when the filters are switched. In other words, the filter can be switched without delay by operating the filter at the switching destination before switching the active filter.

  In the present embodiment, the filter is described as being configured to switch twice between the upper and lower limits of the operation region, but preferably a configuration where the filter is switched twice or more is desirable, as the frequency band to be extracted increases, or As the number of usable filters decreases, it is desirable to increase the number of switching times.

  Next, a second embodiment will be described with reference to FIG.

  FIG. 13 shows a second embodiment of step 3120 in FIG. 3, which is a standby filter setting method considering the time constant of the filter.

  Details will be described with reference to FIG.

  Step 13110 is a target filter acquisition process, in which the target filter set in FIG. 4 is acquired.

  Step 13120 is a process for determining whether or not the target filter is F1.

  If it is F1, the process proceeds to step 13130. If not, the process proceeds to step 13190.

  Step 13130 is an F2 arrival time calculation step. The arrival time to the F2 region shown in FIG. 5 is estimated from the current engine speed, the time change amount of the engine speed, or the current load and the time change amount of the load.

  Step 13140 is an F2 filter time constant acquisition step, in which the filter time constant is calculated from the set value of the F2 filter. Here, the time constant may be calculated by calculation, or a value stored in advance in the microcomputer may be used.

  Step 13150 is an F2 stabilization time calculation process. The stabilization time of F2 is calculated from the time constant calculated in step 13140. Here, the stabilization time is calculated by multiplying the time constant calculated in step 13140 by a predetermined gain, and it is desirable that the stabilization time increases as the time constant increases.

  Step 13160 is a comparison process between the F2 stabilization time and the F2 arrival time. If the F2 arrival time is shorter than the F2 stabilization time, that is, if the F2 region is reached before stabilizing, the process proceeds to step 13180, and F2 is set in the standby filter. If NO, that is, if the stabilization time is longer than the arrival time, the process proceeds to step 13170, and F1 is set in the standby filter. In step 13170, F1 is set in the standby filter, but it may be stopped. In this way, power consumption can be reduced when the filter is realized by hardware, and calculation load can be reduced when the filter is realized by software.

  Step 13190 is a process of determining whether or not the target filter is F2.

  If it is F2, the process proceeds to step 13210. If not, the process proceeds to step 13280.

  Step 13210 is a calculation process of F1 arrival time and F3 arrival time. The arrival times to the F1 region and the F2 region shown in FIG. 5 are estimated from the current engine speed, the time change amount of the engine speed, or the current load and the time change amount of the load, respectively.

  Step 13220 is a process of acquiring time constants of the F1 filter and the F3 filter, and calculates the time constants of the respective filters from the set values of the F1 filter and the F3 filter. Here, the time constant may be calculated by calculation, or a value stored in advance in the microcomputer may be used.

  Step 13230 is a calculation process of F1 stabilization time and F2 stabilization time. From the time constants calculated in step 13220, the stabilization times of F1 and F2 are calculated. Here, the stabilization time is calculated by multiplying the time constant calculated in step 13220 by a predetermined gain, and it is desirable that the stabilization time increases as the time constant increases.

  Step 13240 is a comparison process between the F1 stabilization time and the F1 arrival time. If the F1 arrival time is shorter than the F1 stabilization time, that is, if the F1 region is reached before stabilization, the process proceeds to step 13250, where F1 is set in the standby filter. If NO, that is, if the stabilization time is longer than the arrival time, the process proceeds to step 13260.

  Step 13260 is a comparison process between the F3 stabilization time and the F3 arrival time. When the F3 arrival time is shorter than the F3 stabilization time, that is, when the F3 area is reached before stabilization, the process proceeds to step 13270, and F3 is set in the standby filter.

  Step 13280 is an F2 arrival time calculation step. The arrival time to the F2 region shown in FIG. 5 is estimated from the current engine speed, the time change amount of the engine speed, or the current load and the time change amount of the load.

  Step 13290 is an F2 filter time constant acquisition step, in which the filter time constant is calculated from the set value of the F2 filter. Here, the time constant may be calculated by calculation, or a value stored in advance in the microcomputer may be used.

  Step 13310 is an F2 stabilization time calculation process. The stabilization time of F2 is calculated from the time constant calculated in step 13290. Here, the stabilization time is calculated by multiplying the time constant calculated in step 13290 by a predetermined gain, and it is desirable that the stabilization time increases as the time constant increases.

  Step 13320 is a comparison process between the F2 stabilization time and the F2 arrival time. When the F2 arrival time is shorter than the F2 stabilization time, that is, when the F2 region is reached before stabilization, the process proceeds to step 13330, and F2 is set in the standby filter. If NO, that is, if the stabilization time is longer than the arrival time, the process proceeds to step 13340, and F3 is set in the standby filter. In step 13340, F3 is set for the standby filter, but it may be stopped. In this way, power consumption can be reduced when the filter is realized by hardware, and calculation load can be reduced when the filter is realized by software.

  The F1 stabilization time, F2 stabilization time, and F3 stabilization time are set according to the time constant of the filter, but it is desirable to make the filter stabilization time longer, and preferably the stability time calculated from the time constant is the lower limit. It is desirable to correct the value by the load or the acceleration of the engine speed. When the engine acceleration is slow, it is desirable to correct the filter so that the stabilization time is shortened. When the engine acceleration is abrupt, the filter stabilization time is lengthened and the target filter is set to switch quickly. Is desirable. Further, the switching destination filter may be set to operate according to the engine load.

  The F1 stabilization time, F2 stabilization time, F3 stabilization time, F1 arrival time, F2 arrival time, and F3 arrival time may be estimated from the number of engine combustion cycles.

  Next, the operation of the second example of the control apparatus for an internal combustion engine according to the present embodiment will be described with reference to FIG.

  FIG. 14 is a time chart showing an operation example of the control device for the internal combustion engine according to the second embodiment of the present invention.

  The example of FIG. 14 shows an operation in which the filter A and the filter B are switched while the engine speed is increased, and the knock detection filter used for extracting the knock frequency is finally switched.

  Before time t1 in FIG. 14, since the engine speed is low and the target filter is set to F1, the active filter is filter A, F1 is set to filter A, and the knock detection filter is F1. Since the F2 arrival time (broken line) is longer than the F2 stabilization time, the standby filter is stopped to reduce power consumption or calculation load.

  When F2 arrival time becomes equal to or shorter than F2 stabilization time at time t1 in FIG. 14, F2 is set in the standby filter. Since the target filter is F1, the knock detection filter remains F1.

  When the target filter is switched to F2 at time t2 in FIG. 14, filter B is set as the active filter, and filter 2 is used as a knock detection filter. Since F2 is preset in the filter 2 at time t1, the filter can be switched without delay at time t2. That is, the filter can be switched without delay by starting the F2 filter in advance in consideration of the stabilization time based on the increase in engine speed and the filter time constant.

  When the F3 arrival time (dotted line) becomes equal to or shorter than the F3 stabilization time at time t3 in FIG. 14, the standby filter is set to F3, and F3 is set to the filter A. Since the target filter is F2, the knock detection filter remains F2.

  When the target filter is switched to F3 at time t4 in FIG. 14, filter A is set as the active filter, and filter 1 is used as a knock detection filter. Since F3 is preset in the filter 1 at time t3, the filter can be switched without delay at time t4. That is, the filter can be switched without delay by starting the F3 filter in advance in consideration of the stabilization time based on the increase in the engine speed and the filter time constant. In other words, the filter for switching can be switched without delay by operating before a predetermined time before switching.

  The predetermined time is corrected according to the engine operating state, and is determined from the acceleration of the engine operating state engine speed.

  The predetermined time is set by estimating the time until a switching destination filter is required. Alternatively, the predetermined time may be set by estimating the combustion cycle until the filter to be switched to becomes necessary.

  When the F2 arrival time (broken line) becomes equal to or longer than the F2 stabilization time at time t5 in FIG. 14, the standby filter is set to stop, and the filter B is set to stop, thereby reducing power consumption or calculation load. Since the target filter is F3, the knock detection filter remains F3.

  With the above configuration, it is possible to extract all knocking frequencies when the knocking frequency extracted for each operation region is different and the number of operable filters is smaller than the number of knocking frequencies to be detected. The filter is activated by suppressing the shortage of the number of filters and considering the time constant of the filter in advance for the change of the operation region. In other words, the predetermined time is set according to the constant of the switching destination filter. By doing in this way, it can prevent becoming unstable when the filter is switched.

  In the present embodiment, the filter is described as being configured to switch twice between the upper and lower limits of the operation region, but preferably a configuration that switches twice or more is desirable, and as the frequency band to be extracted increases, Alternatively, it is desirable to increase the number of times of switching as the number of usable filters decreases.

  Although the description is finished above, the present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

DESCRIPTION OF SYMBOLS 1 ... Throttle sensor 2 ... Air flow sensor 3 ... Water temperature sensor 4 ... Vibration detection sensor 7 ... Crank angle sensor 14 ... Accelerator sensor 17 ... Neutral switch 18 ... Air-conditioner switch 19 ... Auxiliary machine load switch 23 ... Injector 30 ... Ignition coil 42 ... Throttle drive motor

Claims (13)

Combustion state detection means for detecting the combustion state of the internal combustion engine;
And knocking filter extractable abnormal combustion of the at least two frequencies to be detected,
In the engine control apparatus having an abnormal combustion detection means for switching the operation of the knocking filter in the operating range of the internal combustion engine,
The engine control device has in advance a first filter that extracts at least a first frequency as a detection target, and a second filter that extracts a frequency different from the first frequency as a detection target,
When foreseeing the occurrence of knocking of a third frequency other than the frequency extracted by the first filter and the second filter,
The abnormal combustion detection means changes the configuration of the first filter or the second filter that is not operating to a third filter that can detect the third frequency as a detection target. A characteristic engine control device. The engine control device according to claim 1,
An engine control device characterized in that the number of knocking filters is smaller than the number of frequencies to be detected . The engine control device according to claim 1,
When the occurrence of knocking of the third frequency is foreseen while the first filter or the second filter is in operation,
The engine control apparatus according to claim 1, wherein the abnormal combustion detection means changes the configuration to the third filter before switching the active filter . The engine control device according to claim 1,
The engine control device characterized in that the third filter is operated before switching according to the engine speed. The engine control device according to claim 1,
The engine control device according to claim 3, wherein the third filter operates before switching according to an acceleration of an engine speed. The engine control device according to claim 1,
The engine control device, wherein the third filter operates in accordance with an engine load. The engine control device according to claim 1,
The engine control device characterized in that the first filter or the second filter in operation is switched twice or more between the upper and lower limits of the engine operating region. The engine control device according to claim 1,
The engine control device according to claim 3, wherein the third filter is operated a predetermined time before switching. The engine control apparatus according to claim 8, wherein
The engine control apparatus according to claim 1, wherein the predetermined time is set according to a time constant of the third filter . The engine control apparatus according to claim 8, wherein
The engine control apparatus according to claim 1, wherein the predetermined time is corrected according to an engine operating state. The engine control apparatus according to claim 10 , wherein
The engine control apparatus characterized in that the engine operating state is an acceleration of an engine speed. The engine control apparatus according to claim 8, wherein
The engine control apparatus according to claim 1, wherein the predetermined time is set by estimating a time until the third filter is required. The engine control apparatus according to claim 8, wherein
The engine control apparatus according to claim 1, wherein the predetermined time is set by estimating a period of a combustion cycle until the third filter is required.

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