JP4799646B2 - Abnormal ignition control device for internal combustion engine - Google Patents

Description

  The present invention relates to an abnormal ignition control device for an internal combustion engine that detects and suppresses pre-ignition and post-ignition generated in the internal combustion engine.

  Pre-ignition and post-ignition are known as abnormal combustion occurring in the engine. The cause of these abnormal combustion is that when the spark plug or the deposit accumulated in the cylinder becomes high temperature and this causes self-ignition as a heat source, or when the compression ratio is high, the mixture gas is high in the compression stroke, There are cases where high pressure leads to self-ignition. Among these, what happens before regular spark ignition is called pre-ignition, and what happens after that is called post-ignition. These abnormal ignitions are generally known (see, for example, Non-Patent Document 1 and Non-Patent Document 2). When this occurs, unpleasant metallic noise, engine output fluctuations, It may lead to damage.

  As a method for detecting pre-ignition and post-ignition, detection by an in-cylinder pressure sensor has been proposed (for example, see Patent Document 1). However, in order to use an in-cylinder pressure sensor in an engine that is mass-produced for automobiles, it has not been widely used at present because of problems such as cost, reliability, and durability. Therefore, as other detection methods, a method of detecting engine vibration due to abnormal ignition with a knock sensor (for example, see Patent Document 1 and Patent Document 2) or a method of detecting by the occurrence of ion current (for example, Patent Document 1, Patent Document 3), a method of detecting from fluctuations in engine rotation speed (for example, see Patent Document 3), and the like have been proposed.

Japanese Patent No. 3669175 Japanese Patent No. 3912032 Japanese Examined Patent Publication No. 7-65558

Ichiro Kimura, Tadami Sakai, “University Lecture Internal Combustion Engine”, Maruzen, 1980, P82-84 Fujio Nagao, “Internal combustion engine lecture, first volume”, Yokendo, 1980, P216-223

  However, the prior art has the following problems. It is obvious that the detection method using an in-cylinder pressure sensor that can directly measure the in-cylinder combustion state is the most accurate method for detecting abnormal ignition. When detected by a knock sensor, ion current, engine speed fluctuation, etc. This is less detectable than in-cylinder pressure sensors. Further, in methods other than these in-cylinder pressure sensors, the detection of abnormal ignition may differ depending on the operating conditions, and when used alone, sufficient detectability cannot be obtained under all operating conditions. For example, when the ignition timing is retarded to about ATDC 20 deg CA in the self-ignition due to compression that occurs at the time of low rotation and high load, relatively weak post-ignition can be detected by ionic current and engine speed fluctuation. However, it may not be detected until strong pre-ignition occurs. On the contrary, when the ignition timing is advanced to about ATDC 5 degCA near the knock limit, a relatively weak post-ignition can be detected by the knock sensor, but there are cases where it cannot be detected at all by the ionic current or the engine speed fluctuation.

  The present invention has been made in order to solve the above-described problems, and by using a plurality of detection methods for detecting abnormal ignition, the intensity of abnormal ignition can be increased by using a single detection method. It is an object of the present invention to obtain an abnormal ignition control device for an internal combustion engine that can accurately detect the above-mentioned and suppress abnormal ignition.

An abnormal ignition control apparatus for an internal combustion engine according to the present invention includes a plurality of physical quantity detection means for respectively detecting physical quantities generated in the internal combustion engine, and a plurality of abnormal ignitions based on the plurality of physical quantities detected by the plurality of physical quantity detection means. When the abnormal ignition determination parameter calculation unit for calculating the respective determination parameters and the plurality of abnormal ignition determination parameters calculated by the abnormal ignition determination parameter calculation unit exceed a preset abnormal combustion determination threshold value. Is an effective determination unit that determines that each is effective, and a parameter that maps the relationship between the abnormal ignition determination parameter and the abnormal ignition intensity only for the abnormal ignition determination parameter that is determined to be effective by the effective determination unit-abnormal ignition Based on the intensity map, the abnormal ignition intensity calculation unit for calculating the abnormal ignition intensity, and the abnormal ignition intensity calculation If the abnormal ignition intensity has been calculated by the unit, the abnormal ignition intensity arbitration unit that mediates the calculated abnormal ignition intensity to calculate the final abnormal ignition intensity, and the final abnormality calculated by the abnormal ignition intensity arbitration unit An abnormal ignition avoidance control unit that performs abnormal ignition avoidance control according to the ignition intensity, and the abnormal ignition intensity calculated by the abnormal ignition intensity calculation unit has a maximum value of heat generation rate and a mass combustion ratio of a predetermined ratio. One of the crank angle positions .

  According to the abnormal ignition control apparatus for an internal combustion engine according to the present invention, by using a plurality of detection methods for detecting abnormal ignition, the intensity of abnormal ignition is accurately detected by using a single detection method. And abnormal ignition can be suppressed.

1 is a diagram showing a schematic configuration of an internal combustion engine according to Embodiment 1 of the present invention. 1 is a block diagram showing a schematic configuration of a control device for an internal combustion engine according to Embodiment 1 of the present invention. FIG. 1 is a block diagram showing a schematic configuration of a knock control device for an internal combustion engine according to Embodiment 1 of the present invention. FIG. It is a block diagram which shows the structure of the abnormal ignition control apparatus of the internal combustion engine which concerns on Embodiment 1 of this invention. It is a figure which shows the relationship between the pre-ignition determination parameter and pre-ignition intensity | strength parameter | index of the abnormal ignition control apparatus of the internal combustion engine which concerns on Embodiment 1 of this invention. It is a flowchart which shows operation | movement of the pre-ignition intensity | strength adjustment part of the abnormal ignition control apparatus of the internal combustion engine which concerns on Embodiment 1 of this invention. It is a flowchart which shows operation | movement of the pre-ignition avoidance control part of the abnormal ignition control apparatus of the internal combustion engine which concerns on Embodiment 1 of this invention.

  A preferred embodiment of an abnormal ignition control apparatus for an internal combustion engine according to the present invention will be described below with reference to the drawings.

Embodiment 1 FIG.
An internal combustion engine abnormal ignition control apparatus according to Embodiment 1 of the present invention will be described with reference to FIGS. 1 is a diagram showing a schematic configuration of an internal combustion engine according to Embodiment 1 of the present invention. In the following, in each figure, the same reference numerals indicate the same or corresponding parts.

  In FIG. 1, an electronically controlled throttle valve 11 that is electronically controlled to adjust the intake air flow rate is provided upstream of the intake system of the internal combustion engine 10. A throttle opening sensor 5 is provided to measure the opening of the electronically controlled throttle valve 11.

  Further, an air flow sensor 4 for measuring the intake air flow rate is provided upstream of the electronically controlled throttle valve 11, and the pressure in the surge tank 16 is disposed on the internal combustion engine 10 side downstream of the electronically controlled throttle valve 11. An intake manifold pressure sensor 6 for measuring the pressure is provided. Note that both the airflow sensor 4 and the intake manifold pressure sensor 6 may be provided, or only one of them may be provided.

  An injector 13 for injecting fuel is provided in the intake passage downstream of the surge tank 16. The injector 13 may be provided so that it can be directly injected into the cylinder of the internal combustion engine 10. Further, the intake valve of the internal combustion engine 10 is provided with an electronically controlled VVA (Variable Valve Actuation) 12, and one or more variable control among the opening / closing timing, the operating angle, and the lift amount of the intake valve is possible. Thus, the effective compression ratio of the internal combustion engine 10 can be varied.

  Further, an ignition coil 14 and a spark plug 15 for igniting an air-fuel mixture in a cylinder of the internal combustion engine 10, and an edge of a plate provided on the crankshaft for detecting the rotational speed and crank angle of the internal combustion engine 10 are detected. A crank angle sensor 3 for detecting the vibration and a knock sensor 1 for detecting vibration of the internal combustion engine 10 are provided. The ignition coil 14 includes an ion current sensor 2 for detecting an ion current.

  FIG. 2 is a block diagram showing a schematic configuration of the control device for the internal combustion engine according to the first embodiment of the present invention.

  In FIG. 2, the engine vibration waveform measured by the knock sensor 1, the pulse synchronized with the edge of the plate provided on the crankshaft output from the crank angle sensor 3, and the intake air measured by the airflow sensor 4. The flow rate, the opening of the electronically controlled throttle valve 11 measured by the throttle opening sensor 5, and the intake manifold pressure measured by the intake manifold pressure sensor 6 are input to an electronic control unit (ECU) 100A. In addition, measured values are input to ECU 100A from various sensors other than those described above, and signals from other controllers (for example, control systems such as automatic transmission control, brake control, and traction control) are also input. Note that the ionic current detected by the ionic current sensor 2 included in the ignition coil 14 may be directly input to the ECU 100A, or once input to a separate controller and processed, and then the final result. The ion current generation position and end position may be sent to the ECU 100A by communication such as CAN.

  The ECU 100A controls the electronically controlled throttle valve 11 by calculating a target throttle opening based on the accelerator opening and the engine operating state. Further, the electronically controlled VVA 12 is controlled according to the operation state at that time, the injector 13 is driven so as to achieve the target air-fuel ratio, and the ignition coil 14 is energized so as to achieve the target ignition timing. When knocking is detected by a method described later, control for suppressing the occurrence of knocking is also performed by setting the target ignition timing to the retard side (retard side). Furthermore, instruction values for various actuators other than the above are also calculated.

  FIG. 3 is a block diagram showing a schematic configuration of the knock control device for the internal combustion engine according to the first embodiment of the present invention.

  In FIG. 3, the ECU 100 </ b> A includes various I / F circuits and a microcomputer 100. The knock control I / F circuit 20 is a low-pass filter (LPF) 21 for removing a high-frequency component of the signal output of the knock sensor 1. The microcomputer 100 includes an A / D converter 31 that converts an analog signal into a digital signal, a ROM area that stores a control program and control constants, a RAM area that stores variables when the program is executed, and the like. It is composed of Further, the microcomputer 100 includes a filter processing unit 32, a peak value calculation unit 33, a threshold calculation unit 34, a knock determination unit 35, a knock intensity calculation unit 36, a retard amount calculation unit 37, and a peak position calculation unit. 38.

  Next, the operation of the abnormal ignition control apparatus for an internal combustion engine according to the first embodiment will be described with reference to the drawings.

  FIG. 4 is a block diagram showing the configuration of the abnormal ignition control apparatus for the internal combustion engine according to the first embodiment of the present invention.

  With reference to FIG. 4, an outline of pre-ignition control for detecting and avoiding abnormal ignition such as pre-ignition (hereinafter referred to as pre-ignition) and post-ignition will be described.

  4, the abnormal ignition control apparatus for an internal combustion engine according to Embodiment 1 of the present invention includes a knock sensor (physical quantity detection means) 1, an ion current sensor (physical quantity detection means) 2, and a crank angle sensor (physical quantity detection means). ) 3, a pre-ignition determination parameter calculation unit (abnormal ignition determination parameter calculation unit) 40, an effective determination unit 50, a pre-ig intensity calculation unit (abnormal ignition intensity calculation unit) 60, and a pre-ig intensity adjustment unit (abnormal ignition intensity adjustment unit) ) 70 and a pre-ignition avoidance control unit (abnormal ignition avoidance control unit) 80 are provided. The preig determination parameter calculation unit 40, the validity determination unit 50, the preig intensity calculation unit 60, the preig intensity adjustment unit 70, and the preig avoidance control unit 80 are realized by a microcomputer 100 (software).

  First, the calculation method of the pre-ignition determination parameter by the knock sensor 1 will be described in detail.

  The signal output from the knock sensor 1 is input to the aforementioned knock control device, where the vibration position 41 and the vibration intensity 42 which are pre-ignition determination parameters are calculated. The knock control device corresponds to the pre-ignition determination parameter calculation unit 40 that calculates the pre-ignition determination parameter by the knock sensor 1.

  The A / D converter 31 of the microcomputer 100 performs A / D conversion and executes it at regular time intervals (for example, 10 μs, 20 μs, etc.). The A / D conversion may be performed constantly, or may be performed only during a period during which knocking occurs (for example, TDC to ATDC 50 ° CA, etc., hereinafter referred to as a knock detection window).

  Next, the filter processing unit 32 performs a filter process for performing a frequency analysis for extracting a frequency discrete component unique to the knock. As this filter processing, for example, filter processing using a digital bandpass filter may be used, or spectrum analysis of the target frequency may be performed by short-time Fourier transform (STFT) processing.

  Next, the peak value calculation unit 33 calculates a peak value and an integral value based on the result of filtering the knock sensor waveform in the aforementioned knock detection window. In the present embodiment, a peak value is used as a value representing a vibration level in the following description. However, an index other than this, for example, an integrated value or the like may be used as a value representing a vibration level.

  Next, the peak value calculated by the peak value calculation unit 33 is first averaged by performing an annealing process according to the following equation (1) in the threshold calculation of the threshold calculation unit 34. Note that VBGL (n) represents an annealing value, VP (n) represents a peak value, and K1 represents an averaging coefficient.

  VBGL (n) = K1 * VBGL (n-1) + (1-K1) * VP (n) (1)

  Subsequently, the threshold calculation unit 34 obtains a threshold value for knock determination by the following equation (2). Note that VTH (n) is a threshold value, Kth is a threshold coefficient, and Vofs is a threshold offset.

  VTH (n) = VBGL (n) × Kth + Vofs (2)

  Alternatively, the threshold value may be calculated by the following equation (3) assuming that the variation in the peak value is a normal distribution. Vsigma (n) represents a standard deviation of peak values, and Kth represents a threshold coefficient (for example, 3).

  VTH (n) = VBGL (n) + Kth × Vsigma (n) (3)

  Next, the knock determination unit 35 compares the peak value with the threshold value to determine whether knock has occurred.

  Subsequently, when it is determined that knock has occurred, the knock strength calculation unit 36 calculates a knock strength VK (n) that is a signal corresponding to the strength of the knock by the following equation (4). Note that VK (n) = 0 when there is no knock.

  VK (n) = VP (n) −VTH (n) (4)

  Next, the retard amount calculation unit 37 calculates the retard amount according to the knock intensity for each ignition by the following equation (5). ΔθR (n) represents the retard amount for each ignition, and Kg represents the retard amount reflection coefficient.

  ΔθR (n) = VK (n) / VTH (n) × Kg (5)

  Using this retard amount, ignition timing control is executed by an ignition timing control device (not shown).

  The peak position calculation unit 38 calculates the peak position based on the result of filtering the knock sensor waveform in the above-described knock detection window. In the present embodiment, the peak position is used as a value representing the vibration position in the following description, but another index, for example, a vibration rising position or the like may be used as a value representing the vibration position.

  The peak position calculated by the peak position calculation unit 38 is stored in the memory (RAM) as the vibration position 41 for preig detection, and the knock intensity calculated by the knock intensity calculation unit 36 is the vibration intensity for preig detection. 42 is stored in a memory (RAM). In this way, the vibration position 41 and the vibration intensity 42, which are pre-ignition determination parameters, are calculated from the output value of the knock sensor 1.

  Next, a method for calculating the pre-ignition determination parameter by the ion current sensor 2 will be described.

  The ion current sensor 2 is a sensor that detects ions generated during combustion as a current by applying a predetermined bias voltage to the spark plug 15 as disclosed in Patent Document 3, for example. The combustion state can be detected. Specifically, since there are almost no ions when not combusting, the ionic current value is almost zero, but it is generated by combustion and thermal ionization as combustion begins and combustion becomes intense and the in-cylinder temperature rises. Since ions increase, the ion current value increases. Thereafter, when combustion ends and the in-cylinder temperature decreases, the ionic current value also decreases and becomes almost zero before reaching the exhaust stroke.

  In order to calculate the ion current generation position 43 by the ion current sensor 2, for example, the microcomputer 100 of the ECU 100A performs an A / D conversion process of the ion current value at every predetermined crank angle, and determines the pre-ignition in the microcomputer 100. In the parameter calculation unit 40, the crank angle at the time when the ion current value exceeds a predetermined value may be set as the ion current generation position. In this way, the generation position 43, which is a pre-ignition determination parameter, is calculated from the output value of the ion current sensor 2.

  Next, a calculation method of the pre-ignition determination parameter by the crank angle sensor 3 will be described.

  As described above, the crank angle sensor 3 detects the edge of the plate provided on the crankshaft to detect the crank angle. The edge is detected at predetermined intervals (determining the crank position every 6 degrees or 10 degrees). The pulse signal generated in synchronization with the edge detection is input to the pre-ignition determination parameter calculation unit 40 in the microcomputer 100 in the ECU 100A, so that the interval between edges (predetermined) The period Δt of the crank angle interval ΔCA can be measured.

  Therefore, if the predetermined crank angle interval ΔCA and the period Δt are used, the angular velocity ω can be calculated by the following equation (6).

  ω (n) = ΔCA (n) / Δt (n) (6)

  Further, the angular acceleration α can be calculated from the angular velocity ω and the period Δt by the following equation (7).

  α (n) = {ω (n) −ω (n−1)} / Δt (n) (7)

  Thereby, the crank angular acceleration at a predetermined crank angle interval at the predetermined crank angle position can be calculated. Based on this, the pre-ignition determination parameter calculation unit 40 confirms in advance the crank angle position where the difference in crank angular acceleration is significant between normal combustion and abnormal combustion, and obtains the crank angular acceleration at that crank angle position. Thus, the angular acceleration 44, which is a pre-ignition determination parameter, is calculated. Further, the crank angular acceleration is obtained for each edge (for example, every 6 degrees or every 10 degrees), and the maximum value and the maximum position during one stroke are obtained. And the maximum angular acceleration position 46 is calculated.

  Next, the calculation process of the validity determination and the abnormal ignition intensity (hereinafter referred to as the pre-ignition intensity) performed for each pre-ignition determination parameter calculated by each sensor will be described with reference to FIGS.

  First, an outline of the validity determination and pre-ig intensity calculation processing will be described with reference to the broken line portions (40, 50, 60) in FIG.

  As described above, the pre-ignition determination parameter calculation unit 40 calculates each pre-ignition determination parameter from the detection value of each sensor. Subsequently, the validity determination unit 50 compares each pre-ignition determination parameter with each abnormal combustion determination threshold value, which will be described later, and determines whether or not abnormal ignition is determined based on each pre-ignition determination parameter. Here, for the pre-ignition determination parameter determined to be invalid (not abnormal ignition), an invalid initial value is substituted for the pre-ig intensity, and this process is terminated. For the pre-ignition determination parameter determined to be valid (abnormal ignition), the pre-ignition intensity calculation unit 60 calculates the pre-ignition intensity, and the process ends. In this way, the preig intensity for each preig determination parameter is calculated.

  Here, the concept of calculating the preig intensity for each preig determination parameter will be described.

  First, when each pre-ignition determination parameter is divided into an intensity system parameter and a position system parameter, the intensity system has vibration intensity 42, angular acceleration 44, and maximum angular acceleration 45, and the position system has vibration position 41 and ion current. A generation position 43 and a maximum angular acceleration position 46 are allocated. In addition, as an index of the pre-ignition strength, the maximum value of the heat generation rate that can be calculated from the in-cylinder pressure and the 10% position of the mass combustion ratio (the crank angle position at which the mass combustion ratio becomes 10%) can be considered. Is a parameter of the intensity system, and the position where the mass combustion ratio is 10% is a parameter of the position system. Here, the relationship between these intensity system parameters and position system parameters is summarized in FIG.

  FIG. 5 shows a schematic image of the evaluation results of the engine (internal combustion engine) performed so far. As shown in FIGS. 5A and 5C, when the maximum heat generation rate is considered as the pre-ignition intensity, the intensity system parameters (vibration intensity 42, angular acceleration 44, angular acceleration maximum value 45) are substantially proportional. It can be seen that there is a relationship, and the position system parameters (vibration position 41, ion current generation position 43, angular acceleration maximum position 46) are substantially inversely proportional.

  Further, as shown in FIGS. 5B and 5D, when the mass combustion ratio 10% position is considered as the pre-ignition intensity, the intensity system parameters (vibration intensity 42, angular acceleration 44, angular acceleration maximum value 45) are as follows. It can be seen that there is a substantially inversely proportional relationship and that there is a substantially proportional relationship with the position system parameters (vibration position 41, ion current generation position 43, angular acceleration maximum position 46).

  Such a relationship is measured in advance by an engine equipped with an in-cylinder pressure sensor, and this is used as a map so that the pre-ignition intensity (heat generation rate maximum value or mass combustion ratio 10% position) is determined from each pre-ig determination parameter. Calculation can be performed easily.

  Based on the above, a specific calculation method for validity determination and pre-ig intensity calculation will be described.

  As preparations required in advance, as described above, the relationship between each pre-ig determination parameter and the pre-ig intensity (maximum value of heat generation rate or mass combustion ratio 10%) is measured in advance by an engine equipped with an in-cylinder pressure sensor. It is necessary to map it. That is, a parameter-preig intensity map obtained by mapping the relationship between the preig determination parameter and the preig intensity is set in advance. Furthermore, an abnormal combustion determination threshold value for determining the validity of the pre-ignition determination parameter is also set from the parameter-pre-ig intensity map.

  The validity determination unit 50 in FIG. 4 performs the validity determination. In the validity determinations 52, 54, and 55 for the intensity system parameters (vibration intensity 42, angular acceleration 44, angular acceleration maximum value 45), the abnormal combustion is more abnormal than the normal combustion. Since it tends to be larger, as described above, it is determined to be effective when it exceeds a preset abnormal combustion determination threshold value (when larger).

  In the validity determinations 51, 53, and 56 for the position system parameters (vibration position 41, ion current generation position 43, angular acceleration maximum position 46), the abnormal combustion tends to be earlier than the normal combustion. It is determined to be effective when it is earlier (when it exceeds the preset abnormal combustion determination threshold). However, in the validity determination 51 for the vibration position 41, only the vibration position may be generated early even during minute vibrations during normal combustion, so that the vibration strength 42 is a predetermined value or more is also added to the validity determination condition. There is a need. In this way, it is possible to determine whether each preig determination parameter is valid or invalid.

  Next, the pre-ig intensity calculation unit 60 (61-66) calculates the pre-ig intensity by performing mapping using the parameter-pre-ig intensity map only for the pre-ig determination parameter determined to be effective by the validity determination unit 50. . For the pre-ignition determination parameter determined to be invalid by the validity determining unit 50, an invalid value such as zero is substituted when the pre-ignition intensity is the maximum value of heat release rate, and ATDC 180 degrees when the mass combustion ratio is 10%. . As described above, each preig intensity can be calculated from each preig determination parameter.

  Next, the pre-ig intensity adjusting unit 70 in FIG. 4 will be described with reference to FIG. FIG. 6 is a flowchart showing the operation of the pre-ignition intensity adjusting unit of the abnormal ignition control apparatus for an internal combustion engine according to the first embodiment of the present invention.

  First, in step 71, the pre-ig intensity adjusting unit 70 confirms whether or not the pre-ig intensity is calculated. Here, the presence / absence of validity determination for each preig determination parameter may be confirmed, or it may be confirmed whether the preig intensity is other than an invalid value. Here, if it is confirmed that the pre-ignition intensity is not calculated at all (all pre-ignition determination parameters are invalid), it is considered that the current combustion is normal combustion. This routine is terminated without performing any operation.

  Next, in step 72, if any of the pre-ig determination parameters is determined to be valid, the pre-ig intensity is adjusted. As the arbitration method, a method of calculating the average value of the pre-ignition intensity determined to be valid or a method of calculating the maximum value is conceivable. The pre-ig intensity that has been arbitrated by such calculation is determined as the final pre-ig intensity in step 73. It is stored in a memory (RAM).

As another arbitration method, as described above, since the accuracy of each pre-ignition determination parameter varies depending on the operating condition, a weighted average value corresponding to the operating condition may be calculated. Specifically, since the detection accuracy by the knock sensor 1 is good when the ignition timing is advanced close to the knock limit, the pre-ig intensity calculated from each sensor is, for example,
Knock sensor 1: Ion current sensor 2: Crank angle sensor 3 = 3: 1: 1
Weighted by the ratio of and averaged.

On the other hand, since the detection accuracy by the ion current sensor 2 and the crank angle sensor 3 is good at the time of delay,
Knock sensor 1: Ion current sensor 2: Crank angle sensor 3 = 1: 2: 2
Weighted by the ratio of and averaged.

Also, at the ignition timing where detection accuracy is the same for all sensors,
Knock sensor 1: Ion current sensor 2: Crank angle sensor 3 = 1: 1: 1
As a result, weighting may not be performed.

  Preig avoidance control, which will be described later, is executed using the final preig intensity calculated as described above.

  Next, the pre-ignition avoidance control unit 80 in FIG. 4 will be described with reference to FIG. FIG. 7 is a flowchart showing the operation of the pre-ignition avoidance control unit of the internal combustion engine abnormal ignition control apparatus according to Embodiment 1 of the present invention.

  When abnormal ignition occurs, it is effective to reduce the temperature in the cylinder of the internal combustion engine 10 to suppress this. Therefore, methods for lowering the in-cylinder temperature include reducing the in-cylinder temperature during the compression stroke by reducing the intake air amount and reducing the effective compression ratio, and increasing the amount of fuel and in-cylinder cooling by retarding the fuel injection timing. Is effective. It is also effective to forcibly scavenge the inside of the cylinder by cutting the fuel for several strokes to lower the temperature in the cylinder. By using these methods in combination, avoidance control according to the strength of abnormal ignition can be performed.

  In other words, if the engine is weakly ignited, it will not damage the engine immediately, so suppression control should be done to prevent sudden torque reduction. If this happens, unpleasant vibrations and metal sounds may occur, and in the worst case, the engine may be damaged. Therefore, here, as an embodiment, a predetermined value for determining the strength of abnormal ignition is set in advance, and when it is determined that the engine is weakly abnormal ignition, only the suppression control based on the intake air amount is executed, thereby making a sudden torque. An explanation will be given of a case in which abnormal ignition is suppressed without causing a down, and when it is determined that there is strong abnormal ignition, the suppression control is executed by the intake air amount and fuel and immediately suppressed so as not to damage the engine. .

  First, in step 81, the pre-ignition avoidance control unit 80 determines whether or not the final pre-ig intensity is greater than a predetermined value. If it is less than this predetermined value, it is weak abnormal ignition, so the process proceeds to step 84, but if it is greater than the predetermined value, the process proceeds to the next step 82.

  In step 82, if it is larger than the predetermined value, it is considered that there is strong abnormal ignition, so in order to quickly suppress the pre-ignition by increasing or cutting the fuel injection amount or delaying the fuel injection timing, The target injection amount and target injection timing are calculated. These values are adapted in advance to the extent to which abnormal ignition can be suppressed by changing the injection amount and injection timing with respect to the pre-ignition intensity, and are stored as a map for the pre-ignition intensity or calculated based on the pre-ignition intensity. Just do it.

  In step 83, the injector 13 is driven according to the target injection amount and target injection timing calculated in this way.

  In step 84, the target intake air amount and the target effective compression ratio are calculated in order to reduce the intake air amount and the effective compression ratio. This is also the same as the suppression control by fuel, and it is adapted to the extent to which abnormal ignition can be suppressed by changing the intake air amount and effective compression ratio in advance with respect to the pre-ig intensity, and whether it is stored as a map for the pre-ig intensity, or the pre-ig intensity It is sufficient to calculate based on.

  In step 85, abnormal ignition can be avoided by driving the electronically controlled throttle valve 11 and the electronically controlled VVA 12 so as to realize the target intake air amount and the target effective compression ratio thus calculated. It becomes.

  According to the present embodiment, by using a plurality of detection methods, an abnormality that accurately detects the intensity of abnormal ignition and performs control for suppressing abnormal ignition according to the intensity by using a single detection method. There is an excellent effect that an ignition control device can be obtained.

  DESCRIPTION OF SYMBOLS 1 Knock sensor, 2 Ion current sensor, 3 Crank angle sensor, 10 Internal combustion engine, 11 Electronically controlled throttle valve, 12 Electronically controlled VVA, 13 Injector, 31 A / D converter, 32 Filter processing part, 33 Peak value calculation Unit, 34 threshold calculation unit, 35 knock determination unit, 36 knock intensity calculation unit, 37 retard amount calculation unit, 38 peak position calculation unit, 40 preig determination parameter calculation unit, 50 validity determination unit, 60 preig intensity calculation unit, 70 preig Strength arbitration unit, 80 pre-ignition avoidance control unit, 100 microcomputer.

Claims (4)

A plurality of physical quantity detection means for respectively detecting physical quantities generated in the internal combustion engine;
An abnormal ignition determination parameter calculation unit for calculating a plurality of abnormal ignition determination parameters, respectively, based on the plurality of physical quantities detected by the plurality of physical quantity detection means;
An effective determination unit that determines that each of the plurality of abnormal ignition determination parameters calculated by the abnormal ignition determination parameter calculation unit is effective when it exceeds a preset abnormal combustion determination threshold;
Only for the abnormal ignition determination parameter determined to be valid by the effective determination unit, the abnormal ignition intensity is calculated based on the parameter-abnormal ignition intensity map in which the relationship between the abnormal ignition determination parameter and the abnormal ignition intensity is mapped. An abnormal ignition intensity calculation unit;
When the abnormal ignition intensity has been calculated by the abnormal ignition intensity calculation unit, an abnormal ignition intensity arbitration unit that calculates the final abnormal ignition intensity by adjusting the calculated abnormal ignition intensity;
An abnormal ignition avoidance control unit that performs abnormal ignition avoidance control according to the final abnormal ignition intensity calculated by the abnormal ignition intensity arbitration unit , and
The abnormal ignition control apparatus for an internal combustion engine, wherein the abnormal ignition intensity calculated by the abnormal ignition intensity calculating unit is either a maximum value of heat generation rate or a crank angle position at which a mass combustion ratio becomes a predetermined ratio . The abnormal ignition control device for an internal combustion engine according to claim 1, wherein the plurality of physical quantity detection means are at least two of a knock sensor, an ion current sensor, and a crank angle sensor. The final abnormal ignition intensity calculated by mediation by the abnormal ignition intensity arbitration unit is one of an average value, a maximum value, and a weighted average value according to operating conditions of the abnormal ignition intensity. Or the abnormal ignition control apparatus of the internal combustion engine of 2 . The abnormal ignition avoidance control unit is
When the final abnormal ignition intensity is larger than a predetermined value for determining the level of abnormal ignition set in advance, the target injection amount and the target injection timing are calculated to drive the injector, and the target intake air amount and the target Calculate the effective compression ratio and drive the electronically controlled throttle valve and electronically controlled VVA,
The electronically controlled throttle valve and the electronically controlled VVA are driven by calculating a target intake air amount and a target effective compression ratio when the final abnormal ignition intensity is equal to or less than the predetermined value. The abnormal ignition control device for an internal combustion engine according to claim 3 .

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