WO2015033371A1 - Dispositif de détection de combustion anormale pour moteur et procédé de détection de combustion anormale pour moteur - Google Patents

Dispositif de détection de combustion anormale pour moteur et procédé de détection de combustion anormale pour moteur Download PDF

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Publication number
WO2015033371A1
WO2015033371A1 PCT/JP2013/005196 JP2013005196W WO2015033371A1 WO 2015033371 A1 WO2015033371 A1 WO 2015033371A1 JP 2013005196 W JP2013005196 W JP 2013005196W WO 2015033371 A1 WO2015033371 A1 WO 2015033371A1
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Prior art keywords
combustion
abnormal combustion
abnormal
engine
knock intensity
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PCT/JP2013/005196
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English (en)
Japanese (ja)
Inventor
安枝　信次
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Yasueda Shinji
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Priority to JP2015535176A priority Critical patent/JPWO2015033371A1/ja
Priority to PCT/JP2013/005196 priority patent/WO2015033371A1/fr
Publication of WO2015033371A1 publication Critical patent/WO2015033371A1/fr

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D35/00—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for
    • F02D35/02—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for on interior conditions
    • F02D35/027—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for on interior conditions using knock sensors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/24—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means
    • F02D41/26—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means using computer, e.g. microprocessor
    • F02D41/28—Interface circuits
    • F02D2041/286—Interface circuits comprising means for signal processing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/24—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means
    • F02D41/26—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means using computer, e.g. microprocessor
    • F02D41/28—Interface circuits
    • F02D2041/286—Interface circuits comprising means for signal processing
    • F02D2041/288—Interface circuits comprising means for signal processing for performing a transformation into the frequency domain, e.g. Fourier transformation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/02—Input parameters for engine control the parameters being related to the engine
    • F02D2200/024—Fluid pressure of lubricating oil or working fluid
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2250/00—Engine control related to specific problems or objectives
    • F02D2250/14—Timing of measurement, e.g. synchronisation of measurements to the engine cycle

Definitions

  • the present invention relates to an engine abnormal combustion detection device and an abnormal combustion detection method for detecting abnormal combustion occurring in a combustion chamber of an engine.
  • the present invention has been made in view of such a problem, and an engine having a configuration capable of accurately discriminating between normal knocking generated under normal ignition and abnormal combustion other than the knocking.
  • An object of the present invention is to provide an abnormal combustion detection device and an abnormal combustion detection method.
  • an abnormal combustion detection apparatus for an engine is an engine that generates engine power by burning a mixture of air and fuel supplied into a combustion chamber.
  • a physical quantity detection means for example, the acceleration detector 12 in the embodiment
  • a knock intensity calculation means for calculating the knock magnitude of each combustion cycle based on the physical quantity detected by the physical quantity detection means (for example, the knock intensity calculating unit 52) in the embodiment and the frequency at which the knock intensity calculated by the knock intensity calculating means is equal to or higher than a predetermined threshold and the knock intensity are continuously equal to or higher than the predetermined threshold over a plurality of combustion cycles.
  • Abnormal combustion determination means for output e.g., abnormal combustion determination section 54 in the embodiment configured to include a, a.
  • the abnormal combustion detection method for an engine according to the present invention is a physical quantity correlated with the combustion state of the combustion chamber in an engine that generates engine power by burning a mixture of air and fuel supplied into the combustion chamber. Detecting a physical quantity detected in the physical quantity detecting step, calculating a knock intensity for each combustion cycle based on the physical quantity detected in the physical quantity detecting step, and determining that the knock intensity calculated in the knock intensity calculating step is equal to or greater than a predetermined threshold value. And abnormal combustion other than normal knocking that occurs under normal ignition based on at least one of the continuity in which the frequency and knock intensity continuously exceed a predetermined threshold over a plurality of combustion cycles And an abnormal combustion determination step for detecting.
  • the frequency at which the knock intensity becomes equal to or higher than a predetermined threshold and the continuity of the knock intensity continuously equal to or higher than the predetermined threshold over a plurality of combustion cycles Based on at least one of them, knocking generated in the combustion chamber of the engine and abnormal combustion other than the knocking (for example, abnormal combustion caused by lubricating oil, abnormal combustion caused by hot surface ignition, etc.) are accurately discriminated. Therefore, it is possible to perform correct avoidance control according to the type of abnormal combustion, and to quickly return the engine to an appropriate combustion state. Also, since the engine is generally equipped with a knock sensor (physical quantity detection means), the knock intensity is used as an index for detecting abnormal combustion other than normal knocking that occurs under normal ignition. By using this, the abnormal combustion detection device can be realized at low cost.
  • the engine abnormal combustion detection device when the knock intensity fluctuates more than a certain value in a plurality of combustion cycles, other abnormal combustion other than normal knocking generated under normal ignition is detected. With such a configuration, it is possible to further improve the detection accuracy of various abnormal combustion based on the combination conditions of frequency and continuity.
  • the engine abnormal combustion detection apparatus when the maximum combustion pressure in the combustion chamber rises above a certain level or when the maximum combustion pressure fluctuates above a certain level in a plurality of combustion cycles, By detecting the abnormal combustion other than the normal knocking that occurs in the combustion chamber, it is possible to reliably detect abnormal combustion that causes a sudden increase in the combustion pressure based on multi-point ignition in the combustion chamber. It becomes possible to do.
  • the frequency at which the knock intensity becomes equal to or higher than a predetermined threshold and the continuity of the knock intensity continuously equal to or higher than the predetermined threshold over a plurality of combustion cycles Based on at least one, normal knocking that occurs under normal ignition and abnormal combustion other than the knocking (for example, abnormal combustion due to lubricating oil, abnormal combustion due to hot surface ignition, etc.) Since it is possible to accurately determine, it is possible to execute correct avoidance control according to the type of abnormal combustion and to quickly return the engine to an appropriate combustion state.
  • abnormal combustion detection method for an engine when the knock intensity fluctuates more than a certain value in a plurality of combustion cycles, other abnormal combustion other than normal knocking that occurs under normal ignition is detected. With such a configuration, it is possible to further improve the detection accuracy of various abnormal combustion based on the combination conditions of frequency and continuity.
  • FIG. 1 shows an abnormal combustion detection apparatus for an engine according to an embodiment of the present invention.
  • a premixed combustion type gasoline engine is illustrated as an example of an engine (internal combustion engine).
  • the present invention can also be applied to other types of engines such as a gas engine.
  • the engine 1 includes a cylinder block 10 having a cylinder space 11, a cylinder head 20 provided so as to cover the upper surface of the cylinder block 10, a piston 30 provided in a reciprocating manner in the cylinder space 11, and a connecting rod 35. And a crankshaft 40 that is coupled to the piston 30 and is driven to rotate by receiving the reciprocating motion of the piston 30.
  • a combustion chamber 2 also referred to as “in-cylinder” is defined by being surrounded by an inner peripheral surface of the cylinder space 11, a cylinder head 20, and a piston 30.
  • the cylinder head 20 is provided with an intake passage 21 and an exhaust passage 23 connected to the combustion chamber 2.
  • An intake valve that opens and closes the intake port is provided at an intake port which is a communication portion between the combustion chamber 2 and the intake passage 21. 22 is provided, and an exhaust valve 24 for opening and closing the exhaust port is provided at an exhaust port which is a communication portion between the combustion chamber 2 and the exhaust passage 23.
  • the intake valve 22 and the exhaust valve 24 are opened and closed at a predetermined timing by a cam mechanism (not shown) that is rotationally driven in conjunction with the crankshaft 40.
  • an air-fuel ratio control device 25 (see FIG. 5), a fuel supply device 26, and the like are provided in the middle of or in front of the intake passage 21, and the compressed air and fuel are mixed through the intake passage 21. Gas (premixed gas) is introduced into the combustion chamber 2.
  • the air-fuel mixture supply method and the fuel injection method there are various types of the air-fuel mixture supply method and the fuel injection method, and any method may be adopted.
  • the cylinder head 20 is provided with an ignition device 27 with the tip (electrode portion) facing the ceiling of the combustion chamber 2, and the air-fuel mixture introduced into the combustion chamber 2 by the operation of the ignition device 27. Is ignited.
  • the operations of the air-fuel ratio control device 25, the fuel supply device 26, the ignition device 27, etc. are controlled by the electronic control unit ECU.
  • the cylinder head 20 is provided with a combustion pressure detector 28 for detecting the pressure in the combustion chamber 2 (referred to as “combustion pressure”).
  • an acceleration detector 12 for detecting vibration (vibration acceleration) generated in the cylinder block 10 is attached to the cylinder block 10.
  • the acceleration detector 12 and the combustion pressure detector 28 constitutes a so-called “knock sensor” and the acceleration detector 12 is employed, it is based on the vibration value.
  • Various abnormal combustion is detected using the knock intensity as an index
  • the combustion pressure detector 28 is employed, various abnormal combustion is detected using the knock intensity based on the combustion pressure as an index.
  • the acceleration detector 12 or the combustion pressure detector 28 may be referred to as a knock sensor 3.
  • a crank angle detector 41 for detecting the rotation angle of the crankshaft 40 is attached to the crankshaft 40.
  • the engine 1 includes both the acceleration detector 12 and the combustion pressure detector 28. However, either one of the acceleration detector 12 or the combustion pressure detector 28 is included. It may be a thing.
  • exhaust stroke When the piston 30 reaches the bottom dead center and further rises, the exhaust valve 24 is opened, and the gas in the combustion chamber 2 is exhausted through the exhaust port (“exhaust stroke”).
  • exhaust stroke When the piston 30 rises to the top dead center, the exhaust valve 24 is closed by the elastic force of the valve spring, while the intake valve 22 is opened again.
  • the series of “intake stroke”, “compression stroke”, “combustion / expansion stroke”, and “exhaust stroke” are repeated each time the piston 30 reciprocates up and down twice.
  • abnormal combustion detection device In the abnormal combustion detection device according to the present embodiment, various abnormal combustions that occur in the engine 1 based on detection information from the detectors 12, 28, 41, etc., are generated under normal ignition. A function of discriminating between knocking and other abnormal combustion (for example, abnormal combustion caused by lubricating oil, abnormal combustion caused by hot surface ignition, etc.) is provided.
  • FIG. 2 is a table comparing the characteristics of the abnormal combustion that is the object of the present embodiment
  • FIG. 3 is a graph showing how the knocking intensity changes with time in each abnormal combustion.
  • abnormal combustion caused by lubricating oil and abnormal combustion caused by hot surface ignition are basically characterized by simultaneous knocking, and hence knocking that occurs under normal ignition thereafter. May also be referred to as “normal knocking”. That is, “normal knocking” means that that occurs under normal ignition by the ignition device 27.
  • “abnormal combustion other than normal knocking” means abnormal combustion due to abnormal ignition, and knocking often occurs at the same time.
  • the characteristics of normal knocking, abnormal combustion caused by lubricating oil, and abnormal combustion caused by hot surface ignition will be described in order with reference to FIGS.
  • Normal knocking is a phenomenon in which the pressure wave reciprocates in the combustion chamber 2 and resonates due to self-ignition of the unburned portion of the air-fuel mixture in the process of increasing the combustion pressure due to flame propagation. .
  • normal knocking tends to occur continuously at a relatively high frequency with a predetermined level of knock intensity compared to the other two abnormal combustions, and its cycle fluctuations. Is relatively small.
  • the “knock strength” is an index indicating the degree of knocking generated in the engine. Further, the maximum combustion pressure Pmax obtained from the combustion pressure, the indicated mean effective pressure Pmi, and their cycle fluctuations are also relatively small compared to the other two abnormal combustions.
  • “Abnormal combustion due to lubricating oil” is a phenomenon in which the lubricating oil staying in the combustion chamber 2 (for example, the lubricating oil that has risen) causes self-ignition to rapidly increase the combustion pressure.
  • the lubricating oil is dispersed in the combustion chamber 2 in the form of mist or steam, self-ignition occurs almost simultaneously at multiple points (multiple positions) in the combustion chamber 2 (and thus causes a sudden pressure increase). Will be.)
  • abnormal combustion caused by the lubricating oil has a feature that knocking occurs simultaneously because the combustion pressure rapidly increases. As shown in FIG. 2 and FIG.
  • FIG. 4 is a graph showing the relationship between the crank angle and the combustion pressure in normal combustion and abnormal combustion (with advance and without advance) due to lubricating oil.
  • the ignition timing does not necessarily advance, and the maximum combustion pressure Pmax increases with multi-point ignition without advance. There are many cases.
  • “Abnormal combustion due to hot surface ignition” is a phenomenon in which the air-fuel mixture comes into contact with the overheated high-temperature portion in the combustion chamber 2 to cause self-ignition and gradually accelerates the ignition timing of the air-fuel mixture. Therefore, knocking occurs at the same time.
  • abnormal combustion resulting from hot surface ignition as shown in FIGS. 2 and 3, a large level of knock intensity is continuously generated and tends to grow severely in a short time. Further, there is a characteristic that the maximum combustion pressure Pmax is significantly higher than that of normal combustion.
  • various abnormal combustion detection methods include (I) a detection method based on occurrence frequency, continuity at which the knock intensity is equal to or greater than a threshold value, and (II) knock.
  • a detection method based on the cycle fluctuation value of the intensity and (III) a detection method based on the cycle fluctuation value of the combustion maximum pressure Pmax, the combustion maximum pressure Pmax, and the cycle fluctuation value of the indicated mean effective pressure Pmi are proposed.
  • FIG. 5 is a functional block diagram of the abnormal combustion detection device 50 according to the first embodiment.
  • the abnormal combustion detection device 50 is mainly composed of a microcomputer equipped with a CPU, ROM, RAM, etc., and the CPU detects abnormal combustion occurring in the engine 1 in accordance with an abnormal combustion detection control program stored in the ROM. To do. Knock sensor 3 (acceleration detector 12 etc.), crank angle detector 28 etc. are electrically connected to abnormal combustion detector 50.
  • the abnormal combustion detection device 50 includes a knock intensity calculation unit 52 that calculates a knock intensity and its cycle fluctuation value based on detection information from the knock sensor 3, and an abnormality that detects abnormal combustion in the cylinder.
  • a combustion determination unit 54 is provided.
  • the electronic control unit ECU is composed mainly of a microcomputer equipped with a CPU, ROM, RAM, etc., and the CPU is based on detection information from various detectors and the like according to a combustion control program stored in the ROM. Execute control.
  • the electronic control unit ECU is electrically connected with an air-fuel ratio control device 25, a combustion supply device 26, an ignition device 27, and the like.
  • the electronic control unit ECU controls the operation of the air-fuel ratio control device 25, the combustion supply device 26, the ignition device 27, and the like to control the combustion control unit 51 that controls the combustion in the cylinder. I have.
  • the knock intensity calculation unit 52 executes predetermined calculation processing based on the vibration value V detected by the knock sensor 3 (acceleration detector 12 or the like) and the crank angle ⁇ detected by the crank angle detector 41. Then, the knock strength is calculated. Specifically, as shown in FIG. 6A, the vibration waveform is subjected to frequency analysis (fast Fourier transform) in a predetermined analysis window, and the power spectrum shown in FIG. 6B is calculated.
  • the setting range ⁇ of the analysis window can be set to an arbitrary range near the top dead center (TDC), and may be set, for example, within a range of 40 degrees near the top dead center.
  • a bandpass filter is applied to a predetermined frequency band (referred to as “knock frequency band”) centered on the knocking natural frequency calculated by the following equation (1), and the vibration fluctuation width ⁇ V of the knock frequency band is calculated.
  • An overall value (root mean square value) is calculated, and this is defined as knock intensity.
  • the speed of sound in the tube is calculated as a function of the temperature in the tube.
  • Knocking natural frequency sound velocity in the pipe / (2 x cylinder diameter) (1)
  • Knock strength calculator 52 also calculates a cycle variation value of the knock strength.
  • the cycle fluctuation value of the knock intensity is an index indicating the degree of fluctuation of the knock intensity in a plurality of cycles. For example, the difference between the maximum value and the minimum value of the knock intensity, standard deviation, COV (covariance) ).
  • the “cycle” means a series of processes of intake, compression, combustion / expansion, and exhaust.
  • the abnormal combustion determination unit 54 executes the above detection methods (I) and (II) singly or in combination with each other, thereby causing abnormal combustion due to knocking, lubricating oil, and hot surface ignition. Various abnormal combustion is detected.
  • the abnormal combustion determination unit 54 uses at least one of the occurrence frequency and continuity as an index for detecting abnormal combustion. Specifically, the abnormal combustion determination unit 54 records the number of cycles (occurrence frequency) at which the knock intensity is equal to or higher than a predetermined threshold (referred to as “reference threshold”) during a predetermined number of cycles, and the occurrence frequency thereof. Is greater than or equal to the first threshold, that is, when the occurrence frequency is high, it is determined that the abnormal combustion is caused by hot surface ignition.
  • a predetermined threshold referred to as “reference threshold”
  • the occurrence frequency is less than the first threshold and greater than or equal to the second threshold, that is, if the occurrence frequency is medium, it is determined that the knocking is normal. Further, when the occurrence frequency is less than the second threshold, that is, when the occurrence frequency is low, it is determined that the abnormal combustion is caused by the lubricating oil.
  • the first threshold value is larger than the second threshold value (first threshold value> second threshold value). This is because, as described above, abnormal combustion caused by lubricating oil is less frequent than normal knocking, and abnormal combustion caused by hot surface ignition is compared with normal knocking. Therefore, it uses the characteristic that the frequency of occurrence is high.
  • the reference threshold value, the first threshold value, and the second threshold value are variables that can be arbitrarily variably set according to the operating state of the engine 1 or the like.
  • the abnormal combustion determination unit 54 performs hot surface ignition when the number of consecutive times is equal to or greater than the third threshold value, that is, when continuity is high. It is determined that the combustion is abnormal combustion. On the other hand, when the number of consecutive times is less than the third threshold value and greater than or equal to the fourth threshold value, that is, when the continuity is medium, it is determined that the knocking is normal. Further, when the number of continuous times is less than the fourth threshold, that is, when the continuity is low, it is determined that the abnormal combustion is caused by the lubricating oil.
  • the third threshold value is larger than the fourth threshold value (third threshold value> fourth threshold value).
  • the third threshold value and the fourth threshold value are variables that can be variably set according to the operating state of the engine 1 or the like.
  • the abnormal combustion determination unit 54 uses the cycle variation value of the knock strength as an index for detecting abnormal combustion. Specifically, the abnormal combustion determination unit 54 determines that abnormal combustion due to the lubricating oil has occurred when the cycle fluctuation value of the knock intensity is equal to or greater than the fifth threshold value. As described above, this utilizes the characteristic that in the case of abnormal combustion caused by lubricating oil, the variation between combustion cycles is larger than that of normal knocking. At this time, the detection method (II) may be used alone, but the detection accuracy of the abnormal combustion can be further improved by combination with the detection method (I).
  • the fifth threshold value is a variable that can be variably set according to the operating state of the engine 1 or the like.
  • the abnormal combustion determination unit 54 transmits detection information related to the abnormal combustion to the combustion control unit 51 of the electronic control unit ECU.
  • the combustion control unit 51 of the electronic control unit ECU executes avoidance control according to the type of abnormal combustion based on the detection information from the abnormal combustion determination unit 54, so that each part of the engine (air-fuel ratio control device 25, fuel supply device 26). The operation of the ignition device 27, etc.).
  • FIG. 7 is a flowchart showing an example of the abnormal combustion detection method.
  • the knock strength calculation unit 52 calculates the knock strength based on the detection information input from the knock sensor 3 (acceleration detector 12 or the like) (step S101).
  • the abnormal combustion determination unit 54 determines whether or not the knock intensity exceeds the reference threshold value (step S102).
  • the abnormal combustion determination unit 54 determines whether the knock intensity is greater than or equal to the reference threshold in the past N cycles or the number of consecutive times that the knock magnitude is greater than or equal to the reference threshold Is calculated (step S103). It is also possible to calculate both the occurrence frequency of knock strength and the number of consecutive times.
  • the abnormal combustion determination unit 54 compares the occurrence frequency or the continuous number obtained in step S103 with a predetermined threshold value (first to fourth threshold values), and compares the abnormal combustion caused by normal knocking and lubricating oil. Then, it is determined which of the abnormal combustion caused by hot surface ignition has occurred (step S104).
  • the combustion control unit 51 of the electronic control unit ECU executes avoidance control according to the type of abnormal combustion detected in step S104 (step S105).
  • avoidance control for knocking as control for retarding the ignition timing
  • avoidance control for abnormal combustion due to hot surface ignition as control for avoiding abnormal combustion due to lubricating oil, such as control to immediately stop the engine 1
  • Control for reducing the output of the engine 1 is executed.
  • FIG. 8 is a functional block diagram of the abnormal combustion detection device 150 according to the second embodiment.
  • the abnormal combustion detection device 150 is mainly composed of a microcomputer equipped with a CPU, ROM, RAM, etc., and the CPU detects abnormal combustion occurring in the engine 1 in accordance with the control program for detecting abnormal combustion stored in the ROM. To do. Knock sensor 3 (combustion pressure detector 28), crank angle detector 28, and the like are electrically connected to abnormal combustion detection device 150.
  • the abnormal combustion detection device 150 includes a knock intensity calculation unit 152 that calculates a knock intensity and its cycle fluctuation value based on detection information from the knock sensor 3 (combustion pressure detector 28), and also knocks. Based on the detection information from the sensor 3 (combustion pressure detector 28), the combustion pressure analysis unit 153 that calculates the maximum combustion pressure Pmax, the indicated mean effective pressure Pmi, and their cycle fluctuation values, and the like, and based on the knock intensity and the combustion pressure An abnormal combustion determination unit 154 that detects abnormal combustion in the cylinder.
  • the electronic control unit ECU is composed mainly of a microcomputer equipped with a CPU, ROM, RAM, etc., and the CPU is based on detection information from various detectors and the like according to a combustion control program stored in the ROM. Execute control.
  • the electronic control unit ECU is electrically connected with an air-fuel ratio control device 25, a combustion supply device 26, an ignition device 27, and the like.
  • the electronic control unit ECU controls the operations of the air-fuel ratio control device 25, the combustion supply device 26, the ignition device 27, etc., and controls the combustion control unit 51 that controls the combustion in the cylinder. I have.
  • Knock intensity calculation unit 152 executes a predetermined calculation process based on combustion pressure P detected by knock sensor 3 (combustion pressure detector 28) and crank angle ⁇ detected by crank angle detector 41. Then, the knock strength is calculated. Specifically, as shown in FIG. 6A, the combustion pressure waveform is subjected to frequency analysis (fast Fourier transform) in a predetermined analysis window, and the power spectrum shown in FIG. 6B is calculated.
  • the setting range ⁇ of the analysis window can be set to an arbitrary range near the top dead center (TDC), and may be set, for example, within a range of 40 degrees near the top dead center.
  • a bandpass filter is applied to a predetermined frequency band (referred to as “knock frequency band”) centered on the knocking natural frequency calculated by the above equation (1), and the combustion pressure fluctuation width ⁇ P in this knock frequency band.
  • the overall value root mean square value is calculated, and this is defined as the knock intensity.
  • Knock strength calculation unit 152 also calculates a cycle variation value of the knock strength.
  • the cycle fluctuation value of the knock intensity is an index indicating the degree of fluctuation of the knock intensity in a plurality of cycles. For example, the difference between the maximum value and the minimum value of the knock intensity, standard deviation, COV (covariance) ).
  • the “cycle” means a series of processes of intake, compression, combustion / expansion, and exhaust.
  • the combustion pressure analysis unit 153 calculates the maximum combustion pressure Pmax, the indicated mean effective pressure Pmi, and their cycle fluctuation values based on the combustion pressure P detected by the knock sensor 3 (combustion pressure detector 28).
  • the maximum combustion pressure Pmax means the maximum value of the combustion pressure (in-cylinder pressure) during one cycle of the combustion chamber 2.
  • the cycle fluctuation value of the maximum combustion pressure Pmax is an index indicating the degree of fluctuation of the maximum combustion pressure Pmax in a plurality of successive cycles. Specifically, the difference between the maximum value and the minimum value of the maximum combustion pressure Pmax. , Standard deviation, COV (covariance), and the like.
  • the indicated mean effective pressure Pmi is a value obtained by dividing the work amount per cycle of each cylinder by the stroke volume.
  • the cycle fluctuation value of the indicated mean effective pressure Pmi is an index indicating the degree of fluctuation of the indicated mean effective pressure Pmi in a plurality of consecutive cycles, and specifically, the maximum value and the minimum value of the indicated mean effective pressure Pmi. Difference, standard deviation, COV (covariance), and the like.
  • the abnormal combustion determination unit 154 executes the detection methods (I), (II), and (III) described above alone or in combination with each other to prevent abnormal combustion caused by knocking, lubricating oil, and hot surface ignition. Detect abnormal combustion caused by it.
  • the abnormal combustion determination unit 154 uses at least one of the occurrence frequency and continuity as an index for detecting abnormal combustion. Specifically, the abnormal combustion determination unit 154 records the number of cycles (occurrence frequency) at which the knock intensity is equal to or greater than a predetermined threshold (referred to as “reference threshold”) during a predetermined number of cycles, and the occurrence frequency thereof. Is greater than or equal to the first threshold, that is, when the occurrence frequency is high, it is determined that the abnormal combustion is caused by hot surface ignition.
  • a predetermined threshold referred to as “reference threshold”
  • the occurrence frequency is less than the first threshold and greater than or equal to the second threshold, that is, when the occurrence frequency is medium, it is determined that the knocking is normal. Further, when the occurrence frequency is less than the second threshold, that is, when the occurrence frequency is low, it is determined that the abnormal combustion is caused by the lubricating oil.
  • the first threshold value is larger than the second threshold value (first threshold value> second threshold value). This is because, as described above, abnormal combustion caused by lubricating oil is less frequent than normal knocking, and abnormal combustion caused by hot surface ignition is compared with normal knocking. Therefore, it uses the characteristic that the frequency of occurrence is high.
  • the reference threshold value, the first threshold value, and the second threshold value are variables that can be arbitrarily variably set according to the operating state of the engine 1 or the like.
  • the abnormal combustion determination unit 154 performs hot surface ignition when the number of consecutive times is equal to or greater than the third threshold value, that is, when continuity is high. It is determined that the combustion is abnormal combustion.
  • the third threshold value is larger than the fourth threshold value (third threshold value> fourth threshold value).
  • the third threshold value and the fourth threshold value are variables that can be variably set according to the operating state of the engine 1 or the like.
  • the abnormal combustion determination unit 154 uses the knock strength cycle variation value as an index for detecting abnormal combustion. Specifically, the abnormal combustion determination unit 154 determines that abnormal combustion due to the lubricating oil has occurred when the cycle variation value of the knock intensity is equal to or greater than the fifth threshold value. As described above, this utilizes the characteristic that in the case of abnormal combustion caused by lubricating oil, the variation between combustion cycles is larger than that of normal knocking. At this time, the detection method (II) may be used alone, but the detection accuracy of the abnormal combustion can be further improved by combination with the detection method (I).
  • the fifth threshold value is a variable that can be variably set according to the operating state of the engine 1 or the like.
  • the abnormal combustion determination unit 154 uses the maximum combustion pressure Pmax, the cycle fluctuation of the maximum combustion pressure Pmax, and the cycle fluctuation value of the indicated mean effective pressure Pmi as an index for detecting abnormal combustion. Use one of the following. Specifically, the abnormal combustion determination unit 154 determines that the abnormal combustion is other than normal knocking when the maximum combustion pressure Pmax is higher than the cycle average value by a sixth threshold or more.
  • the cycle average value means an average value of the combustion maximum pressure Pmax in a plurality of cycles (for example, 100 times).
  • the abnormal combustion determination unit 154 determines that the abnormal combustion is other than normal knocking. Furthermore, when the cycle fluctuation value of the indicated mean effective pressure Pmi is equal to or greater than a preset eighth threshold value, the abnormal combustion determination unit 154 determines that the abnormal combustion is other than normal knocking. At this time, this detection method (III) may be used alone, but the detection accuracy of the abnormal combustion can be further improved by combination with the detection methods (I) and (II).
  • the sixth threshold value, the seventh threshold value, and the eighth threshold value are variables that can be variably set according to the operating state of the engine 1 or the like.
  • the abnormal combustion determination unit 154 transmits detection information related to the abnormal combustion to the combustion control unit 51 of the electronic control unit ECU.
  • the combustion control unit 51 of the electronic control unit ECU executes avoidance control according to the type of abnormal combustion based on the detection information from the abnormal combustion determination unit 154, so that each part of the engine (air-fuel ratio control device 25, fuel supply device 26). The operation of the ignition device 27, etc.).
  • FIG. 9 is a flowchart showing an example of the abnormal combustion detection method.
  • the knock intensity calculation unit 152 calculates the knock intensity based on the detection information input from the knock sensor 3 (combustion pressure detector 28) (step S201).
  • the abnormal combustion determination unit 154 determines whether or not the knock intensity is greater than or equal to a reference threshold value (step S202).
  • step S202 When the knock magnitude is equal to or higher than the reference threshold value (step S202: YES), the abnormal combustion determination unit 154 causes the occurrence frequency of knock intensity equal to or higher than the reference value in the past N cycles, or the knock intensity is equal to or higher than the reference threshold value.
  • the number of continuous times is calculated (step S203). It is also possible to calculate both the occurrence frequency of knock strength and the number of consecutive times.
  • the knock strength calculation unit 152 also calculates the cycle variation value of the knock strength (step S204).
  • the combustion pressure analysis unit 153 calculates at least one of the maximum combustion pressure Pmax in the cylinder, the cycle variation value of the maximum combustion pressure Pmax, and the cycle variation value of the indicated mean effective pressure Pmi.
  • the abnormal combustion determination unit 154 obtains (I) knock intensity occurrence frequency, continuity, (II) knock fluctuation cycle fluctuation value, (III) maximum combustion pressure Pmax, obtained in steps S203 to S205 above. Comparing the cycle fluctuation value of the maximum combustion pressure Pmax and the cycle fluctuation value of the indicated mean effective pressure Pmi with the first to eighth threshold values, and comprehensively judging these judgment items, normal knocking and lubrication It is determined which of abnormal combustion caused by oil and abnormal combustion caused by hot surface ignition has occurred.
  • there are various methods for determining abnormal combustion For example, if any one of the detection items satisfies the determination criteria (I) to (III), abnormal combustion is detected, or all detection items are detected. Then, when the determination criteria (I) to (III) are satisfied, abnormal combustion may be detected, or the weight may be changed for each detection item.
  • the combustion control unit 51 of the electronic control unit ECU executes avoidance control according to the type of abnormal combustion detected in step S206 (step S207).
  • avoidance control for knocking as control for retarding the ignition timing
  • avoidance control for abnormal combustion due to hot surface ignition as control for avoiding abnormal combustion due to lubricating oil, such as control to immediately stop the engine 1
  • Control for reducing the output of the engine 1 is executed.
  • step S202 If the knock strength is not greater than or equal to the reference threshold (step S202: NO), steps S203 and S204 are skipped and the process proceeds to step S205. This is for improving the reliability of detection accuracy by executing abnormal combustion detection based on the maximum combustion pressure Pmax or the like even when the knock magnitude is not equal to or higher than the reference threshold value.
  • the frequency at which the knock intensity is equal to or higher than the reference threshold, and the knock intensity is continuously equal to or higher than the reference threshold over a plurality of combustion cycles Based on at least one of the continuity, the abnormal combustion occurring in the combustion chamber 2 of the engine 1 is accurately determined as normal knocking, abnormal combustion due to lubricating oil, abnormal combustion due to hot surface ignition, or the like. Therefore, it is possible to perform correct avoidance control according to the type of abnormal combustion and to quickly return the engine 1 to an appropriate combustion state.
  • a knock sensor physical quantity detection means
  • an acceleration detector is mounted on an engine, so that the knock intensity can be used as an index for detecting other abnormal combustion other than normal knocking.
  • the abnormal combustion detection device 50 can be realized at low cost.
  • abnormal combustion other than normal knocking
  • abnormal combustion caused by lubricating oil and abnormal combustion caused by hot surface ignition have been exemplified so far.
  • a major feature is that it is possible to distinguish abnormal combustion from normal knocking.
  • the present invention is not limited to the above-described embodiment, and can be improved as appropriate without departing from the gist of the present invention.
  • the knocking intensity may be calculated using sound or the ion state in the combustion gas as another physical quantity having a correlation with the combustion state of the combustion chamber.
  • abnormal combustion detection device 50 (150) may be integrated in the electronic control unit ECU, or may be configured as a separate device independent of the electronic control unit ECU.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Combined Controls Of Internal Combustion Engines (AREA)

Abstract

La présente invention concerne un dispositif (50) de détection de combustion anormale pour un moteur, ledit moteur (1) étant construit de façon à produire l'énergie du moteur par la combustion d'un mélange air-carburant qui est alimenté dans une chambre de combustion (2), comprenant : un détecteur d'accélération (12) permettant de détecter une quantité physique en corrélation avec un état de combustion de la chambre de combustion ; une unité (52) de calcul d'intensité de cognement permettant de calculer une intensité de cognement dans chaque cycle de combustion sur la base de la quantité physique détectée par le détecteur d'accélération (12) ; et une unité (54) de détection de combustion anormale permettant de détecter une combustion anormale, à l'exception du cognement normal qui se produit lors de l'allumage normal dans la chambre de combustion (2), au moins sur la base de la fréquence, c'est-à-dire la fréquence à laquelle l'intensité de cognement calculée par l'unité (52) de calcul d'intensité de cognement devient égale ou supérieure à une valeur de seuil prescrite, ou en continu, c'est-à-dire sur la base d'un état dans lequel l'intensité de cognement reste égale ou supérieure à la valeur de seuil prescrite sur plusieurs cycles de combustion.
PCT/JP2013/005196 2013-09-03 2013-09-03 Dispositif de détection de combustion anormale pour moteur et procédé de détection de combustion anormale pour moteur WO2015033371A1 (fr)

Priority Applications (2)

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JP2015535176A JPWO2015033371A1 (ja) 2013-09-03 2013-09-03 エンジンの異常燃焼検出装置及びエンジンの異常燃焼検出方法
PCT/JP2013/005196 WO2015033371A1 (fr) 2013-09-03 2013-09-03 Dispositif de détection de combustion anormale pour moteur et procédé de détection de combustion anormale pour moteur

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JP2017198110A (ja) * 2016-04-26 2017-11-02 スズキ株式会社 内燃機関の可変動弁制御装置
EP3392493A4 (fr) * 2016-01-22 2019-01-16 Mitsubishi Heavy Industries, Ltd. Procédé de détection de cognement, procédé de commande de période d'allumage et système de commande de période d'allumage
US11319871B2 (en) * 2017-07-18 2022-05-03 Prometheus Applied Technologies, Llc Lube oil controlled ignition engine combustion

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JP2008057438A (ja) * 2006-08-31 2008-03-13 Honda Motor Co Ltd 内燃機関の点火時期制御装置
JP2009203883A (ja) * 2008-02-27 2009-09-10 Mitsubishi Heavy Ind Ltd 内燃機関の故障原因推定方法および装置
JP2012112300A (ja) * 2010-11-24 2012-06-14 Toyota Motor Corp 内燃機関の制御装置
JP2012149552A (ja) * 2011-01-18 2012-08-09 Toyota Motor Corp 内燃機関の制御装置
JP2013050096A (ja) * 2011-08-31 2013-03-14 Fuji Heavy Ind Ltd エンジンの燃焼状態診断装置
JP2013104371A (ja) * 2011-11-15 2013-05-30 Toyota Motor Corp 内燃機関の制御装置

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JP2009203883A (ja) * 2008-02-27 2009-09-10 Mitsubishi Heavy Ind Ltd 内燃機関の故障原因推定方法および装置
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EP3392493A4 (fr) * 2016-01-22 2019-01-16 Mitsubishi Heavy Industries, Ltd. Procédé de détection de cognement, procédé de commande de période d'allumage et système de commande de période d'allumage
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JP2017198110A (ja) * 2016-04-26 2017-11-02 スズキ株式会社 内燃機関の可変動弁制御装置
US11319871B2 (en) * 2017-07-18 2022-05-03 Prometheus Applied Technologies, Llc Lube oil controlled ignition engine combustion
US11542860B2 (en) 2017-07-18 2023-01-03 Prometheus Applied Technologies Lube oil controlled ignition engine combustion

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