WO2022153611A1 - Dispositif de commande de moteur à combustion interne - Google Patents

Dispositif de commande de moteur à combustion interne Download PDF

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Publication number
WO2022153611A1
WO2022153611A1 PCT/JP2021/035058 JP2021035058W WO2022153611A1 WO 2022153611 A1 WO2022153611 A1 WO 2022153611A1 JP 2021035058 W JP2021035058 W JP 2021035058W WO 2022153611 A1 WO2022153611 A1 WO 2022153611A1
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WIPO (PCT)
Prior art keywords
jet
internal combustion
combustion engine
ignition
control device
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PCT/JP2021/035058
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English (en)
Japanese (ja)
Inventor
直樹 米谷
英一郎 大畠
敦史 島田
健太 光藤
義寛 助川
賢吾 熊野
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日立Astemo株式会社
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Priority to CN202180077865.6A priority Critical patent/CN116472399A/zh
Publication of WO2022153611A1 publication Critical patent/WO2022153611A1/fr

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B19/00—Engines characterised by precombustion chambers
    • F02B19/12—Engines characterised by precombustion chambers with positive ignition
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D45/00—Electrical control not provided for in groups F02D41/00 - F02D43/00
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/40—Engine management systems

Definitions

  • the present invention relates to an internal combustion engine control device.
  • a gasoline engine in which a mixture of fuel and air is formed in a combustion chamber and burned by ignition or self-ignition.
  • a sub-chamber type flame jet ignition hereinafter, sub-chamber combustion
  • an air-fuel mixture is ignited in a sub-combustion chamber, which is a minute space of several cc, and a flame jet is injected into the main combustion chamber.
  • sub-chamber combustion a sub-chamber type flame jet ignition
  • a spark plug In a general gasoline engine, a spark plug is fixed to the upper part of the main combustion chamber so that the tip is exposed to the combustion chamber. Then, at the start of combustion, sparks due to electric discharge are generated from the spark plug to directly ignite the air-fuel mixture in the main combustion chamber.
  • a sub-chamber is provided in the upper part of the combustion chamber, and the spark plug is fixed so as to be exposed in the sub-chamber.
  • This sub-chamber is provided with a sub-chamber injection hole that communicates with the main combustion chamber.
  • the air-fuel mixture is first ignited in the sub-chamber.
  • a jet containing a high temperature and unburned air-fuel mixture is ejected from the sub-chamber injection hole toward the main combustion chamber side, and the air-fuel mixture on the main combustion chamber side is ignited by this jet.
  • ignition occurs at multiple points at the same time, and combustion progresses more rapidly than when the sub chamber is not used, so combustion stability is improved.
  • the sub-chamber combustion makes it possible to carry out lean combustion, which burns an air-fuel mixture whose fuel is thinner than the theoretical air-fuel ratio, in a higher dilution state.
  • the reduction improves thermal efficiency.
  • the combustion gas can reach the abnormal combustion generation region before the abnormal combustion such as knocking occurs, and as a result, the knocking suppression effect can be obtained.
  • the optimum ignition timing can be taken even in a high load region, the exhaust loss is reduced, and the thermal efficiency is further improved as compared with the case where the sub chamber is not used.
  • Patent Document 1 includes a technology including a pressure sensor that detects the pressure in the sub-combustion chamber and an ignition control unit that controls ignition of the spark plug according to the operating state of the internal combustion engine and the detected pressure in the sub-combustion chamber. Is described.
  • Patent Document 1 has a problem that a pressure sensor for detecting the pressure in the sub-chamber is required and the system cost increases.
  • the higher the strength of the jet ejected from the sub chamber the more stable ignition of the air-fuel mixture becomes possible.
  • the jet strength is too high, the heat loss to the wall surface of the sub chamber and the wall surface of the main combustion chamber increases. As a result, fuel consumption may increase and the effect of reducing fuel consumption due to combustion in the sub-chamber may decrease. If the jet strength is further increased, the pressure fluctuation in the main combustion chamber due to the jet ejection may induce knocking. Therefore, it is required to accurately estimate the jet strength in order to adjust the jet strength to an appropriate range while balancing combustion stability and heat loss.
  • the purpose of this object is to provide an internal combustion engine control device that can estimate the jet strength without using a pressure sensor that detects the pressure in the sub chamber in consideration of the above problems.
  • the internal combustion engine control device includes a main combustion chamber facing the piston, a sub-combustion chamber, a spark plug, a crank shaft, a crank angle sensor, a cylinder, and a knock sensor. And controls an internal combustion engine equipped with.
  • the sub-combustion chamber communicates with the main combustion chamber.
  • the spark plug is mounted inside the sub-combustion chamber.
  • the crank shaft is connected to the piston.
  • the crank angle sensor detects the rotation angle of the crank shaft.
  • the cylinder forms the main combustion chamber.
  • the knock sensor detects the vibration of the cylinder.
  • the internal combustion engine control device includes an ignition time estimation unit, a crank angle information acquisition unit, a rotation fluctuation acquisition unit, and a jet intensity estimation unit.
  • the ignition time estimation unit estimates the ignition time of the air-fuel mixture in the main combustion chamber by the jet injected from the sub-combustion chamber based on the knock sensor signal detected by the knock sensor.
  • the crank angle information acquisition unit acquires the crank angle information detected by the crank angle sensor.
  • the rotation fluctuation acquisition unit calculates the amount of rotation speed change that occurs after the ignition time based on the crank angle information.
  • the jet intensity estimation unit estimates the jet intensity by calculating the rotation speed change rate that occurs after the ignition time based on the rotation speed change amount calculated by the rotation fluctuation acquisition unit and the ignition time estimated by the ignition time estimation unit. ..
  • the jet strength can be accurately estimated without using a pressure sensor that detects the pressure in the sub chamber.
  • FIG. 1 It is a schematic block diagram which shows the system structure of the internal combustion engine equipped with the internal combustion engine control device which concerns on the 1st Embodiment example. It is a schematic block diagram which shows the structure around the cylinder of the internal combustion engine which mounted the internal combustion engine control device which concerns on the 1st Embodiment example. It is a block diagram which shows the structure of the internal combustion engine control device which concerns on the 1st Embodiment example. It is a block diagram which shows the structure of the jet intensity estimation processing in the internal combustion engine control device which concerns on the 1st Embodiment example. It is a figure explaining the combustion consumption amount and the heat loss amount by the difference of a jet intensity, and FIG.
  • FIG. 5A is a figure which shows the difference between the pressure of a sub chamber and the pressure of a main combustion chamber by a difference of a jet intensity.
  • FIG. 5B is a diagram showing the relationship between the difference in jet intensity and the combustion consumption rate
  • FIG. 5C is a diagram showing the relationship between the difference in jet intensity and the amount of heat loss.
  • the changes in pressure, pressure difference, rotation speed and vibration (acceleration) of the auxiliary chamber and the main combustion chamber per one combustion cycle are shown.
  • FIG. 6 (a) shows the pressure in the auxiliary chamber
  • FIG. 6 (b) shows the main combustion.
  • the pressure in the chamber, FIG. 6 (c) is the pressure difference,
  • FIG. 6 (d) is the rotation speed, and
  • FIG. 6 (e) is the vibration (acceleration).
  • FIG. 8A shows a waveform showing an output value of the knock sensor
  • FIG. 8B shows a knock sensor signal.
  • FIG. 8C is a diagram showing an absolute value of the filter output value. It is a graph which shows the accuracy of the estimation result of the jet intensity estimated by the internal combustion engine control device which concerns on the 1st Embodiment example of the estimation result of the conventional jet intensity.
  • FIG. 11A is a graph showing an example of the increase / decrease process
  • FIG. 11B is a graph showing another example of the increase / decrease process, showing the jet intensity increase / decrease process in the internal combustion engine control device according to the first embodiment
  • FIG. 12A is a graph showing an example of the increase / decrease process
  • FIG. 12B is a graph showing another example of the increase / decrease process, showing the jet intensity increase / decrease process in the internal combustion engine control device according to the first embodiment.
  • FIG. 1 is a schematic configuration diagram showing a system configuration of the internal combustion engine of this example.
  • FIG. 2 is a schematic configuration diagram showing a configuration around a cylinder of an internal combustion engine.
  • the internal combustion engine 100 shown in FIG. 1 is an in-cylinder injection type internal combustion engine (direct injection engine) that directly injects fuel made of gasoline into the cylinder.
  • the internal combustion engine 100 is a four-cycle engine that repeats four strokes of an intake stroke, a compression stroke, a combustion (expansion) stroke, and an exhaust stroke. Further, the internal combustion engine 100 is, for example, a multi-cylinder engine including four cylinders (cylinders). The number of cylinders of the internal combustion engine 100 is not limited to four, and may have six or eight or more cylinders.
  • the internal combustion engine 100 includes an air flow sensor 1, an electronically controlled throttle valve 2, an intake pressure sensor 3, a supercharger 4, an intercooler 7, and a cylinder 14.
  • the air flow sensor 1, the electronically controlled throttle valve 2, the intake pressure sensor 3, the compressor 4a of the supercharger 4, and the intercooler 7 are arranged at positions up to the cylinder 14 in the intake pipe 6.
  • the air flow sensor 1 measures the intake air amount and the intake air temperature.
  • the electronically controlled throttle valve 2 is driven so as to be openable and closable by a drive motor (not shown). Then, the opening degree of the electronically controlled throttle valve 2 is adjusted based on the accelerator operation of the driver. As a result, the amount of air taken into the intercooler 7 and the cylinder 14 is adjusted.
  • the compressor 4a is a supercharger that supercharges the intake air.
  • a rotational force is transmitted to the compressor 4a by a turbine 4b, which will be described later.
  • the intercooler 7 is arranged on the upstream side of the cylinder 14, and is arranged on the downstream side of the electronically controlled throttle valve 2 and the airflow sensor 1. Then, the intercooler 7 cools the intake air.
  • the internal combustion engine 100 includes an injector 13 for injecting fuel into the cylinder of the cylinder 14, an ignition device 16 including an ignition coil 16 for supplying ignition energy, and an ignition plug 17, and a sub.
  • a chamber 8 and a knock sensor 47 are provided for each cylinder 14.
  • the ignition coil 16 generates a high voltage under the control of the internal combustion engine control device 20 and applies it to the spark plug 17. As a result, sparks are generated in the spark plug 17.
  • the spark plug 17 is arranged in the sub chamber 8 provided in the cylinder 14.
  • the hollow sub chamber 8 is inserted into the cylinder of the cylinder 14. Therefore, the internal combustion engine 100 of this example is divided into a main combustion chamber 14a formed in the cylinder of the cylinder 14 and a sub-combustion chamber formed by the sub chamber 8.
  • the sub chamber 8 is fixed to the cylinder head with its tip exposed in the main combustion chamber 14a.
  • a sub-chamber injection hole 8a communicating with the main combustion chamber 14a is formed at the tip of the sub-chamber 8.
  • the sub-combustion chamber and the main combustion chamber 14a formed by the sub-chamber 8 are. It communicates with the auxiliary chamber injection hole 8a. Then, the air-fuel mixture is taken into the sub-chamber 8 from the main combustion chamber 14a via the sub-chamber injection hole 8a.
  • the air-fuel mixture in the sub-combustion chamber is burned by the spark generated in the spark plug 17.
  • the flame generated in the sub chamber 8 passes through the sub chamber injection hole 8a and is ejected as a plurality of flame jets into the main combustion chamber 14a, ignites the air-fuel mixture in the main combustion chamber 14a, and the main combustion is performed.
  • the flame jet injected from the sub-chamber injection hole 8a is simply referred to as a jet.
  • ignition occurs at multiple points at the same time, combustion proceeds more rapidly than in the case where the sub chamber 8 is not used, and the stability of combustion is improved.
  • the flame jet injected from the sub-chamber injection hole 8a is simply referred to as a jet.
  • a voltage sensor (not shown) is attached to the ignition coil 16.
  • the voltage sensor measures the primary side voltage or the secondary side voltage of the ignition coil 16. Then, the voltage information measured by the voltage sensor is sent to the internal combustion engine control device 20 which is an ECU (Engine Control Unit).
  • ECU Engine Control Unit
  • the cylinder head of the cylinder 14 is provided with a variable valve 5. As shown in FIG. 2, it has an intake side timing mechanism 5a, an exhaust side timing mechanism 5b, an intake valve 31, and an exhaust valve 32.
  • the intake valve 31 is arranged at the intake port to which the intake pipe 6 of the cylinder 14 is connected, and the exhaust valve 32 is arranged at the exhaust port of the cylinder 14 to which the exhaust pipe 15 described later is connected.
  • the variable valve 5 adjusts the valve opening and closing magnetism of the intake valve 31 and the exhaust valve 32 by the intake side timing mechanism 5a and the exhaust side timing mechanism 5b. As a result, the air-fuel mixture flowing into the cylinder of the cylinder 14 or the exhaust gas discharged from the cylinder is adjusted. By adjusting the variable valve 5, the intake amount and the internal EGR amount of all the cylinders 14 are adjusted.
  • the piston 18 is slidably arranged in the cylinder of the cylinder 14.
  • the piston 18 compresses the mixture of fuel and gas that has flowed into the cylinder of the cylinder 14. Then, the piston 18 reciprocates in the cylinder of the cylinder 14 due to the combustion pressure generated in the cylinder.
  • a crank shaft 48 is connected to the piston 18 via a connecting rod.
  • crank angle sensor 49 is provided to detect the angle of the crank shaft 48.
  • the crank angle sensor 49 detects teeth provided at predetermined angular intervals (for example, 6 deg) in the circumferential direction of the crank shaft 48.
  • the knock sensor 47 is attached to the side surface portion of the cylinder 14 or the cylinder head.
  • the knock sensor 47 is an acceleration sensor that detects the vibration of the cylinder 14.
  • the position where the knock sensor 47 is provided is not limited to the side surface portion of the cylinder 14, and may be any position where vibration of the cylinder 14 can be detected, such as the upper part of the cylinder head.
  • the vibration signal (acceleration information) of the cylinder 14 detected by the knock sensor 47 is output to the internal combustion engine control unit (ECU) 20, which will be described later. Then, when the ECU 20 determines that the vibration signal from the knock sensor 47 exceeds the preset knock threshold value, the ECU 20 detects the occurrence of knocking.
  • ECU internal combustion engine control unit
  • the injector 13 is controlled by an internal combustion engine control unit (ECU) 20, which will be described later, to inject fuel into the cylinder of the cylinder 14.
  • ECU internal combustion engine control unit
  • a high-pressure fuel pump (not shown) is connected to the injector 13.
  • the fuel whose pressure has been increased by the high-pressure fuel pump is supplied to the injector 13.
  • a fuel pressure sensor for measuring the fuel injection pressure is provided in the fuel pipe connecting the injector 13 and the high-pressure fuel pump.
  • the port injection injector 13B may be attached to the intake pipe 6, and fuel may be injected from the port injection injector 13B into the intake port.
  • the exhaust pipe 15 is provided with a turbine 4b, an electronically controlled wastegate valve 11, a three-way catalyst 10, and an air-fuel ratio sensor 9.
  • the turbine 4b is rotated by the exhaust gas passing through the exhaust pipe 15 and transmits the rotational force to the compressor 4a.
  • the electronically controlled wastegate valve 11 adjusts the exhaust flow path flowing through the turbine 4b.
  • the three-way catalyst 10 purifies harmful substances contained in the exhaust gas by an oxidation / reduction reaction. Further, the air-fuel ratio sensor 9 is arranged on the upstream side of the three-way catalyst 10. Then, the air-fuel ratio sensor 9 detects the air-fuel ratio of the exhaust gas passing through the exhaust pipe 15.
  • the internal combustion engine 100 includes an EGR flow path tube 40 that recirculates exhaust gas (EGR gas) from the downstream side of the three-way catalyst 10 to the upstream side of the compressor 4a and the downstream side of the air flow sensor 1. ..
  • the EGR flow path tube 40 is provided with an EGR cooler 42, an EGR valve 41, and a differential pressure sensor 43.
  • the EGR cooler 42 cools the EGR gas.
  • the EGR valve 41 controls the EGR flow rate that regulates the flow rate of the EGR gas passing through the EGR flow path pipe 40.
  • a differential pressure sensor 43 that detects the differential pressure before and after the EGR valve 41 is attached in the vicinity of the EGR valve 41.
  • the differential pressure before and after the EGR valve 41 is the difference between the pressure on the upstream side and the pressure on the downstream side of the EGR valve 41 in the EGR flow path pipe 40.
  • the EGR temperature sensor 44 is arranged downstream of the EGR valve 41. The EGR temperature sensor 44 detects the temperature of the EGR gas flowing through the EGR flow path tube 40.
  • a part of the exhaust gas purified by the three-way catalyst 10 flows into the EGR flow path pipe 40 without being discharged to the outside, and is used as EGR gas.
  • the EGR gas After passing through the EGR cooler 42 and the EGR valve 41, the EGR gas joins the fresh air taken in upstream of the compressor 4a. After that, the mixed gas of EGR gas and fresh air flows into the cylinder 14 after passing through the intercooler 7 and the electronically controlled throttle valve 2.
  • the signals detected by each sensor such as the air flow sensor 1, the intake pressure sensor 3, and the knock sensor 47 are sent to the internal combustion engine control device 20 which is an ECU (Engine Control Unit). Further, the amount of depression of the accelerator pedal, that is, the signal detected by the accelerator opening sensor 12 that detects the accelerator opening is also sent to the internal combustion engine control device 20.
  • the internal combustion engine control device 20 calculates the required torque based on the main signal of the accelerator opening sensor 12. That is, the accelerator opening degree sensor 12 is used as a required torque detection sensor for detecting the required torque for the internal combustion engine 100. Further, the internal combustion engine control device 20 calculates the rotation speed of the internal combustion engine 100 based on the output signal of a crank angle sensor (not shown). Then, the internal combustion engine control device 20 optimally optimizes the main operating amounts of the internal combustion engine 100 such as air flow rate, fuel injection amount, ignition timing, and fuel pressure, based on the operating state of the internal combustion engine 100 obtained from the outputs of various sensors. Calculate.
  • the fuel injection amount calculated by the internal combustion engine control device 20 is converted into a valve opening pulse signal and output to the injector 13. Further, the ignition timing calculated by the internal combustion engine control device 20 is output to the spark plug 17 as an ignition signal. Further, the throttle opening calculated by the internal combustion engine control device 20 is output to the electronically controlled throttle valve 2 as a throttle drive signal. Further, the EGR valve opening degree calculated by the internal combustion engine control device 20 is output to the EGR valve 41 as an EGR valve opening degree driving signal.
  • FIG. 3 is a block diagram showing the configuration of the internal combustion engine control device 20.
  • the internal combustion engine control device 20 which is an ECU (Engine Control Unit) includes an input circuit 21, an input / output port 22, a RAM (RandomAccessMemory) 23c, and a ROM (ReadOnlyMemory) 23b. , CPU (Central Processing Unit) 23a. Further, the internal combustion engine control device 20 has an ignition control unit 24.
  • ECU Engine Control Unit
  • RAM RandomAccessMemory
  • ROM ReadOnlyMemory
  • CPU Central Processing Unit
  • the suction flow rate from the air flow sensor 1, the intake pressure from the intake pressure sensor 3, and the coil primary voltage or secondary voltage from the voltage sensor are input to the input circuit 21. Further, information measured by various sensors such as accelerator opening degree, rotation speed, humidity, air amount, crank angle, ignition device information, and knock sensor information is input to the input circuit 21.
  • the input circuit 21 performs signal processing such as noise reduction on the input signal and sends it to the input / output port 22.
  • the value input to the input port of the input / output port 22 is stored in the RAM 23c.
  • the ROM 23b stores a control program that describes the contents of various arithmetic processes executed by the CPU 23a, a MAP, a data table, and the like used for each process.
  • the RAM 23c is provided with a storage area for storing the value input to the input port of the input / output port 22 and the value representing the operation amount of each actuator calculated according to the control program. Further, a value representing the operation amount of each actuator stored in the RAM 23c is sent to the output port of the input / output port 22.
  • the ignition signal set in the output port of the input / output port 22 is sent to the ignition coil 16 via the ignition control unit 24.
  • the ignition control unit 24 controls the energization timing and energization time of the ignition coil 16. Further, the ignition control unit 24 controls the discharge energy at the spark plug 17.
  • the present invention is not limited to this.
  • a part of the ignition control unit 24 or all of the ignition control unit 24 may be mounted on a control device different from the internal combustion engine control device 20.
  • the internal combustion engine control device 20 estimates the intensity of the jet injected from the sub-chamber injection hole 8a of the sub-chamber 8 based on the output signals from various sensors, and controls the ignition timing at the spark plug 17.
  • FIG. 4 is a block diagram showing a configuration of jet intensity estimation processing in the internal combustion engine control device 20.
  • the internal combustion engine control device 20 includes a knock sensor signal acquisition unit 101, a bandwidth / threshold acquisition unit 102, a crank angle information acquisition unit 103, a rotation fluctuation acquisition unit 104, and an ignition time estimation unit. It has 105 and a crank shaft acceleration start time estimation unit 106. Further, the internal combustion engine control device 20 includes a jet intensity estimation unit 107, a jet intensity comparison unit 108, an ignition timing output unit 109, and a jet intensity upper limit value / lower limit value calculation unit 110.
  • the knock sensor signal acquisition unit 101 is connected to the knock sensor 47 and acquires the knock sensor signal from the knock sensor 47 and the vibration information of the cylinder 14, that is, the acceleration information.
  • the knock sensor signal acquisition unit 101 is connected to the ignition time estimation unit 105, and outputs the acquired knock sensor signal to the ignition time estimation unit 105.
  • Bandwidth / threshold value acquisition unit 102 is input with engine speed information, engine shape information, and the like.
  • the shape information of the engine is the number of cylinders 14 mounted on the engine, that is, the number of cylinders.
  • the bandwidth / threshold acquisition unit 102 sets the bandwidth set value when filtering the knock sensor signal in the ignition time estimation unit 105, and the threshold used for the ignition time estimation process is used for engine speed information. And the shape information of the engine.
  • the bandwidth / threshold value acquisition unit 102 outputs the acquired bandwidth and threshold value to the ignition time estimation unit 105.
  • the bandwidth / threshold value acquisition unit 102 sets the low frequency side of the bandwidth so that the natural frequency of the engine and the mechanical vibration due to rotation are not included. That is, the higher the engine speed, the higher the natural frequency, so the lower limit of the bandwidth is set larger.
  • the natural frequency varies depending on the number of cylinders of the engine, that is, a 4-cylinder engine or a 3-cylinder engine. Therefore, the bandwidth / threshold value acquisition unit 102 changes the lower limit of the bandwidth based on the number of cylinders of the engine to be controlled so that the natural frequency is not included in the set value of the bandwidth.
  • the bandwidth / threshold value acquisition unit 102 is set so that the threshold value becomes smaller as the engine speed and the engine load become smaller.
  • the ignition time estimation unit 105 filters the knock sensor signal output from the knock sensor signal acquisition unit 101 based on the bandwidth output from the bandwidth / threshold value acquisition unit 102, and extracts the combustion component. .. Further, the ignition time estimation unit 105 estimates the ignition time by the jet (jet start time t jet ) based on the extracted combustion component and the threshold value output from the bandwidth / threshold value acquisition unit 102. Then, the ignition time estimation unit 105 outputs the estimated ignition time to the crank shaft acceleration start time estimation unit 106.
  • the crank shaft acceleration start time estimation unit 106 indicating the ignition time correction unit accelerates the crank shaft 48 based on the ignition time output from the ignition time estimation unit 105 and the time delay caused by the piston mechanism stored in advance. Is estimated, that is, the crank shaft acceleration start timing t acc is estimated. That is, the rank axis acceleration start time estimation unit 106 corrects the ignition time based on the time delay caused by the piston mechanism. Then, the crank shaft acceleration start time estimation unit 106 outputs the estimated crank shaft acceleration start timing to the jet intensity estimation unit 107.
  • the crank angle information acquisition unit 103 is connected to the crank angle sensor 49, and acquires crank angle information from the crank angle sensor 49. Then, the crank angle information acquisition unit 103 outputs the acquired crank angle information to the rotation fluctuation acquisition unit 104.
  • the rotation fluctuation acquisition unit 104 acquires (calculates) the amount of rotation change that occurs after the ignition time based on the crank angle information.
  • the rotation fluctuation acquisition unit 104 acquires the amount of change in the rotation speed for each distance between the teeth provided on the crank shaft 48. Further, the rotation fluctuation acquisition unit 104 outputs the acquired rotation speed change amount to the jet intensity estimation unit 107.
  • the jet strength estimation unit 107 estimates the jet strength based on the crank shaft acceleration start timing and the fluctuation amount of the rotation speed. Then, the jet intensity estimation unit 107 outputs the estimated jet intensity to the jet intensity comparison unit 108.
  • the jet intensity comparison unit 108 compares the jet intensity estimated by the jet intensity estimation unit 107 with the upper limit value and the lower limit value calculated by the jet intensity upper limit value / lower limit value calculation unit 110. Then, the jet intensity comparison unit 108 outputs the comparison result to the ignition timing output unit 109.
  • the ignition timing output unit 109 controls the ignition timing based on the result of comparison by the jet intensity comparison unit 108.
  • FIG. 5A shows the difference (pressure difference) between the pressure in the sub chamber 8 and the pressure in the main combustion chamber 14a due to the difference in jet strength.
  • the vertical axis shows the pressure difference [MPa] and the horizontal axis shows the crank angle.
  • FIG. 5B is a diagram showing the relationship between the difference in jet intensity and the combustion consumption rate
  • FIG. 5C is a diagram showing the relationship between the difference in jet intensity and the amount of heat loss to the wall surface of the main combustion chamber 14a.
  • the vertical axis in FIG. 5B shows the heat consumption rate ISFC [g / kWh]
  • the vertical axis in FIG. 5C shows the heat loss amount [W].
  • the horizontal axis in FIGS. 5B and 5C indicates the jet intensity.
  • the pressure difference becomes the maximum value when the sub chamber injection hole 8a ejects from the sub chamber 8 to the main combustion chamber 14a. Then, the maximum value of this pressure difference is defined as the jet intensity. Further, the higher the jet intensity ejected from the sub chamber 8, the more stable the ignition of the air-fuel mixture is. However, when the jet strength is high, as shown in FIG. 5C, the heat loss to the wall surface of the sub chamber 8 and the main combustion chamber 14a increases. As a result, as shown in FIG. 5B, the fuel consumption rate (fuel consumption) may increase, and the fuel consumption reduction effect of the sub-combustion chamber may decrease.
  • FIG. 6 shows the pressure in the sub chamber 8
  • FIG. 6 (b) shows the pressure in the main combustion chamber 14a
  • FIG. 6 (c) shows the pressure difference
  • FIG. 6 (d) shows the number of revolutions
  • FIG. 6 (e) shows the acceleration. That is, the output value of the knock sensor is shown.
  • the data shown in FIGS. 6 (a) and 6 (b) directly plot the measured waveforms.
  • the data shown in FIG. 6 (c) is data obtained by filtering the data obtained by taking the difference between the data shown in FIGS. 6 (a) and 6 (b) and performing noise reduction processing. ..
  • the pressure in the sub-chamber 8 reaches its first peak at top dead center. After that, the pressure rises again due to combustion and reaches the second peak. Then, as shown in FIG. 6B, the pressure behavior of the main combustion chamber 14a is almost the same as the pressure behavior of the sub chamber 8. However, as shown in FIGS. 6 (a) and 6 (b), a slight phase difference occurs between the two. Therefore, immediately after the pressure in the sub chamber 8 starts to rise due to combustion, the pressure difference between the sub chamber 8 and the main combustion chamber 14a reaches a peak as shown in FIG. 6 (c). The moment when the peak of this pressure difference is reached is the timing at which the jet is injected from the sub chamber 8 into the main combustion chamber 14a, and is regarded as the start time of the jet.
  • FIG. 6D is a diagram in which the engine speed is calculated based on the signal detected by the crank angle sensor 49.
  • the crank angle sensor 49 having a crank angle detection interval of 6 deg is used. That is, the crank angle sensor 49 detects the teeth provided on the crank shaft 48 at every 6 deg crank angle. Then, the crank angle information acquisition unit 103 detects a time difference from the time when one previous tooth is detected, obtains the time required for the crank shaft 48 to advance 6 deg based on the time difference, and obtains the time required for the crank shaft 48 to advance by 6 deg from this time. The number of rotations is calculated.
  • the engine speed constantly fluctuates by several tens of rpm in one combustion cycle.
  • a negative torque is generated, so that the rotation speed decreases.
  • the piston 18 is pressed by the combustion pressure, so that the top dead center is 360 deg. 450 deg. From after ATDC to the middle of the expansion process. The number of revolutions increases toward ATDC.
  • the frequency of the vibration waveform is changed at the start time of the jet, but there are many scenes where vibration is generated other than the combustion time. It is considered that this is mainly the load fluctuation on the engine side and the mechanical vibration when opening and closing the valve. Therefore, these effects can be eliminated by performing appropriate filtering.
  • the relationship between the engine speed and the pressure in the main combustion chamber 14a will be described.
  • the torque generated during combustion that is, the combustion torque ⁇ comb
  • the torque generated during combustion is the following number 1 from the friction torque ⁇ fric , the inertia torque ⁇ inner , the load torque ⁇ load , and the inertia J of the engine rotation system. It is represented by.
  • the combustion torque ⁇ comb in order to obtain the combustion torque ⁇ comb , it is necessary to calculate the differential value d ⁇ of the angular velocity ⁇ .
  • the angular velocity ⁇ measured by the crank angle sensor 49 contains various noises. Therefore, when normal differentiation is performed, this noise is emphasized and an accurate torque waveform cannot be reproduced. Therefore, in order to avoid the emphasis of noise due to differentiation, the combustion torque ⁇ comb may be estimated using the result of cutting the high frequency component included in the angular velocity ⁇ .
  • the differential value d ⁇ of the angular velocity ⁇ is referred to as a rotation speed change rate.
  • the estimated combustion ⁇ comb includes an offset due to the friction torque ⁇ fric and the load torque ⁇ load . Therefore, this offset amount is estimated and corrected by pre-adaptation.
  • the geometric features of the connecting rod of the 4-cylinder engine can be used to cancel this offset and obtain the corrected estimated torque ⁇ compression .
  • the relationship between the estimated torque ⁇ compression after this correction and the engine speed, that is, the angular velocity ⁇ is the following equation 2.
  • the pressure in the main combustion chamber 14a that is, the in-cylinder pressure Pcomb is calculated from the obtained estimated torque ⁇ compression .
  • the relationship between the estimated torque ⁇ compression and the in-cylinder pressure P comb is determined by the piston mechanism, and is therefore represented by the following equation 3.
  • a coil indicates the cross-sectional area of the main combustion chamber 14a
  • R indicates the length of the crank arm
  • ⁇ indicates the angle between the crank arm and the central axis.
  • FIG. 7 is an image diagram showing a method of estimating the rotation speed change rate d ⁇ .
  • the horizontal axis represents the time and the vertical axis represents the engine speed (angular velocity ⁇ ).
  • the black circles shown in FIG. 7 indicate the detection signal of the crank angle sensor 49 (crank angle sensor signal).
  • the clan angle sensor signal is a discrete value whose output value is updated for each tooth spacing.
  • the engine speed between the teeth is calculated by linearly interpolating the engine speed in the front and rear sections thereof, so that the line graph is as shown in the solid lines A1 and A2 shown in FIG.
  • the solid line A1 shows the estimation method of this example, and the solid line A2 shows the conventional estimation method.
  • the dotted line shown in FIG. 7 shows the actual rotation speed behavior.
  • the rotation speed change amount ⁇ in the section (t x + 1 ⁇ t x ) where acceleration is generated by the jet after the ignition timing is calculated by the rotation speed fluctuation acquisition unit 104 based on the following equation 5.
  • the rotation speed change rate d ⁇ is calculated using only the signal of the crank angle sensor 49. That is, the rotation speed change rate d ⁇ is calculated by dividing the rotation speed change amount ⁇ by the length of the section (t x + 1 ⁇ t x ), as shown in Equation 6 below.
  • the rotation speed change rate d ⁇ calculated by Equation 6 represents the change in the average rotation speed in the section of the crank angle of 6 deg, and corresponds to the slope of the solid line A2 shown in FIG.
  • the influence is smoothed and sufficient estimation accuracy cannot be obtained.
  • the rotation speed change rate d ⁇ is calculated using the signal of the knock sensor 47, which is an acceleration sensor, and the crank angle signal of the crank angle sensor 49.
  • the knock sensor signal acquisition unit 101 acquires the signal of the knock sensor 47 shown in FIG. 6 (e).
  • the ignition time estimation unit 105 processes the knock sensor signal acquired by the knock sensor signal acquisition unit 101.
  • FIG. 8A is a waveform showing an output value (knock sensor signal) of the knock sensor 47
  • FIG. 8B is a waveform showing a filter output value obtained by filtering the knock sensor signal
  • FIG. 8C is a diagram showing an absolute value of the filter output value.
  • the ignition time estimation unit 105 filters the knock sensor signal shown in FIG. 8A to obtain the filter output value shown in FIG. 8B. That is, the ignition time estimation unit 105 extracts the vibration component caused by combustion by filtering the knock sensor signal.
  • the ignition time estimation unit 105 performs a bandpass filter on the knock sensor signal using the bandwidth output from the bandwidth / threshold value acquisition unit 102 as a filter process.
  • the band region of the bandpass filter was set to 1.0 kHz to 2.0 kHz.
  • the lower limit of the band region is set to 1.0 kHz.
  • the upper limit of the band region is set to 2.0 kHz.
  • the bandwidth that is, the bandwidth is not limited to the above-mentioned 1.0 kHz to 2.0 kHz, and as described above, the bandwidth / threshold value acquisition unit 102 provides engine speed information and engine shape information. It is set appropriately based on the above.
  • the ignition time estimation unit 105 converts the filter output value shown in FIG. 8B into an absolute value, and obtains the waveform shown in FIG. 8C, that is, the amplitude of vibration. Then, the ignition time estimation unit 105 determines the timing at which the vibration amplitude exceeds the threshold value output from the bandwidth / threshold value acquisition unit 102 as the jet start timing, and obtains the jet start time t jet .
  • the threshold value is appropriately set by the bandwidth / threshold value acquisition unit 102 based on the engine speed.
  • the crank shaft acceleration start time estimation unit 106 estimates the crank shaft acceleration start timing t acc based on the jet start time t jet . As shown in Equation 4 above, there is a response delay due to the inertial mass of the piston mechanism and the crank shaft 48 from the increase in pressure in the main combustion chamber 14a to the increase in rotation speed. Therefore, the crank shaft acceleration start time estimation unit 106 is provided with a plurality of profiles of the in-cylinder pressure Pcomb ( ⁇ ) of the main combustion chamber 14a at which the pressure increase start timing by the jet is changed.
  • the response of the rotation speed change rate d ⁇ ( ⁇ ) to those profiles is calculated, and the time delay ⁇ t ( ⁇ ) from the increase in pressure in the main combustion chamber 14a to the occurrence of the increase in rotation speed is used as a table for the crank shaft. It is stored in the acceleration start time estimation unit 106.
  • crank shaft acceleration start timing t acc is calculated by the following equation 7.
  • crank shaft acceleration start time estimation unit 106 corrects the response delay caused by the piston mechanism, so that the actual acceleration start timing of the crank shaft 48 is accurate from the ignition time by the jet based on the knock sensor signal. It can be detected well.
  • the jet intensity estimation unit 107 calculates the rotation speed change rate d ⁇ using the rotation speed detected by the crank angle sensor 49, starting from the acceleration start timing of the crank shaft 48. That is, the jet intensity estimation unit 107 uses the rotation speed change amount ⁇ calculated in the above-mentioned equation 5 and the crank shaft acceleration start timing tac calculated in the equation 7, and the rotation speed change rate based on the equation 8. Calculate ⁇ .
  • ⁇ calculated by Equation 8 corresponds to the slope of the solid line A1 shown in FIG.
  • the calculation start point of the rotation speed change rate ⁇ is the crank shaft estimated by the knock sensor 47 from the detection time tx of the teeth of the crank angle sensor 49. It can be seen that the acceleration start timing is changed to tacc .
  • the solid line A1 obtained by the estimation method of this example can be closer to the actual rotation speed behavior shown by the dotted line than the solid line A2 obtained by the conventional estimation method.
  • the rotation speed change rate ⁇ is calculated with the calculation start point always set to the time tx regardless of the ignition timing by the jet. As a result, it is not possible to obtain a time resolution finer than the tooth spacing detected by the crank angle sensor 49.
  • the rotation speed change rate ⁇ is calculated with the crank shaft acceleration start timing tac as the calculation start point, the rotation speed change rate considering the jet start timing that fluctuates depending on the engine state. ⁇ can be calculated.
  • the jet intensity I_jet can be calculated indirectly based on the following equation tens using the rotation speed change rate ⁇ .
  • P pre is the pressure of the auxiliary combustion chamber.
  • the jet intensity I_jet can be estimated by estimating the rotation speed change rate ⁇ .
  • FIG. 9 is a graph showing the accuracy of the conventional jet intensity estimation result and the jet intensity estimation result of this example.
  • the horizontal axis of each graph shows the rotation speed change rate d ⁇ .
  • the vertical axis of each graph in FIG. 9 shows the pressure difference between the sub-combustion chamber and the main combustion chamber 14a, that is, the jet intensity.
  • the maximum value of the pressure difference is set to 0 deg. ATC, 3deg. ATC, 6deg. It is a plot of averaging 5 consecutive cycles with ATC.
  • the correlation coefficient between the rotation speed change rate d ⁇ and the jet intensity is 0.68.
  • the correlation coefficient between the rotation speed change rate d ⁇ and the jet strength is 0.87. It has become.
  • the accuracy of the jet strength estimation result of this example is higher than the accuracy of the conventional jet strength estimation result using only the crank angle sensor 49. That is, by using the information of the knock sensor 47 together, the time resolution of the rotation speed change rate d ⁇ can be improved, and the jet intensity can be estimated accurately without using the pressure sensor that detects the pressure in the sub chamber. can.
  • FIG. 10 is a flowchart showing a jet intensity correction control operation.
  • the internal combustion engine control device 20 determines whether or not the warming up of the engine is completed (step S11).
  • the jet strength is significantly reduced, and the combustion on the main combustion chamber 14a side may become unstable. Therefore, when it is determined in the process of step S11 that the warming up of the engine is not completed (NO determination in step S11), the internal combustion engine control device 20 ends the process without performing the jet strength correction process.
  • step S11 When it is determined in the process of step S11 that the warming up of the engine is completed (YES determination in step S11), the knock sensor signal acquisition unit 101 acquires knock sensor information from the knock sensor 47 (step S12). Then, the knock sensor signal acquisition unit 101 outputs the acquired knock sensor information (knock sensor signal) to the ignition time estimation unit 105.
  • the ignition time estimation unit 105 filters the knock sensor signal and extracts the combustion component (step S13).
  • the ignition time estimation unit 105 performs a bandpass filter on the knock sensor signal using the bandwidth output from the bandwidth / threshold value acquisition unit 102.
  • the filter output value shown in FIG. 8B can be obtained from the knock sensor signal shown in FIG. 8A.
  • the ignition time estimation unit 105 estimates the ignition time t jet by the jet based on the filter output value from which the combustion component is extracted (step S14). That is, the ignition time estimation unit 105 converts the filter output value into an absolute value as described above, and obtains the waveform shown in FIG. 8C, that is, the amplitude of vibration. Then, the ignition time estimation unit 105 estimates the timing when the threshold value output from the bandwidth / threshold value acquisition unit 102 is exceeded as the ignition time t jet by the jet. Further, the ignition time estimation unit 105 outputs the estimated ignition time t jet by the jet to the crank shaft acceleration start time estimation unit 106.
  • crank angle information acquisition unit 103 acquires crank angle information from the crank angle sensor 49 (step S15). Then, the crank angle information acquisition unit 103 outputs the acquired crank angle information to the rotation fluctuation acquisition unit 104. Further, the rotation speed change acquisition unit 104 calculates the rotation speed change amount ⁇ from the equation 5, and outputs the calculated rotation speed change amount ⁇ to the jet intensity estimation unit 107.
  • crank shaft acceleration start time estimation unit 106 estimates the crank shaft acceleration start timing (time) t acc based on the jet start time t jet and the equation 6 (step 16). Then, the crank shaft acceleration start time estimation unit 106 outputs the estimated crank shaft acceleration start time tac to the jet intensity estimation unit 107.
  • the jet intensity estimation unit 107 estimates the jet intensity I_jet from the rotation speed change rate d ⁇ that occurs after the acceleration start time tacc , based on the rotation speed change amount ⁇ and the crank shaft acceleration start time tacc. (Step S17). That is, the jet intensity estimation unit 107 calculates the rotation speed change rate d ⁇ based on the equation 8, and estimates the rotation speed change rate d ⁇ as the jet intensity I_jet. Then, the jet intensity estimation unit 107 outputs the estimated jet intensity I_jet to the jet intensity comparison unit 108.
  • the jet intensity comparison unit 108 determines whether or not the jet intensity I_jet is equal to or greater than the lower limit value Imin output from the jet intensity upper limit value / lower limit value calculation unit 110 (step S18). When it is determined in the process of step S18 that the jet intensity I_jet is smaller than the lower limit value Imin (NO determination in step S18), the internal combustion engine control device 20 performs the jet intensity increase process (step S19). When the jet intensity increasing process in step S19 is completed, the process returns to step S12 again.
  • step S18 when it is determined that the jet intensity I_jet is equal to or higher than the lower limit value Imin (YES determination in step S18), the process proceeds to the process of step S20.
  • the jet intensity comparison unit 108 determines whether or not the jet intensity I_jet is equal to or greater than the upper limit value Imax output from the jet intensity upper limit value / lower limit value calculation unit 110.
  • step S20 when it is determined that the jet intensity I_jet is larger than the upper limit value Imax (NO determination in step S20), the internal combustion engine control device 20 executes the jet intensity reduction process (step S21). When the jet intensity increasing process in step S21 is completed, the process returns to step S12 again.
  • step S20 When it is determined in the process of step S20 that the jet intensity I_jet is equal to or less than the upper limit value Imax (YES determination in step S20), the internal combustion engine control device 20 determines that the jet intensity I_jet is within an appropriate range. , End control.
  • FIG. 11A is a graph showing an example of jet intensity increase / decrease processing, in which the horizontal axis represents the jet intensity and the vertical axis represents the ignition timing.
  • the ignition timing output unit 109 corrects the ignition timing in the retard direction as the jet intensity I_jet becomes stronger. By retarding the ignition timing, the center of gravity of combustion is delayed, so that the combustion temperature in the sub chamber 8 is lowered. Thereby, the jet intensity I_jet can be reduced.
  • the ignition timing output unit 109 corrects the ignition timing in the advance angle direction. By advancing the ignition timing, the center of gravity of combustion is advanced and the combustion temperature in the sub chamber 8 rises. Thereby, the jet intensity I_jet can be increased.
  • FIG. 11B is a graph showing another example of jet intensity increase / decrease processing, in which the horizontal axis represents the jet intensity and the vertical axis represents the EGR rate target value [%].
  • the internal combustion engine control device 20 controls the EGR rate target value according to the jet intensity I_jet. That is, the stronger the jet intensity I_jet, the higher the EGR rate target value is corrected.
  • Increasing the EGR rate increases the dilution rate of the air-fuel mixture. As a result, the combustion temperature in the sub chamber 8 is lowered, and the jet intensity I_jet can be reduced.
  • the EGR rate target value is corrected to be low.
  • the dilution rate of the air-fuel mixture becomes low.
  • the combustion temperature in the sub chamber 8 rises, and the jet intensity I_jet can be increased.
  • FIG. 12A is a graph showing another example of jet intensity increase / decrease processing, in which the horizontal axis represents the jet intensity and the vertical axis represents the A / F target value.
  • the internal combustion engine control device 20 controls the A / F target value according to the jet intensity I_jet. That is, the stronger the jet intensity I_jet, the higher the A / F target value is corrected.
  • the dilution ratio of the air-fuel mixture is increased.
  • the combustion temperature in the sub chamber 8 is lowered, and the jet intensity I_jet can be reduced.
  • the jet intensity I_jet is weak, the A / F target value is corrected to be low.
  • the dilution ratio of the air-fuel mixture becomes low.
  • the combustion temperature in the sub chamber 8 rises, and the jet intensity I_jet can be increased.
  • FIG. 12B is a graph showing another example of the jet intensity increase / decrease process, in which the horizontal axis represents the jet intensity and the vertical axis represents the ignition energy [mJ].
  • the internal combustion engine control device 20 controls the ignition energy according to the jet intensity I_jet. That is, the stronger the jet intensity I_jet, the lower the ignition energy.
  • the ignition delay timing is increased, the combustion center of gravity is delayed, and the combustion temperature in the sub chamber 8 is lowered, as in the case of retarding the ignition timing.
  • the jet intensity I_jet can be reduced.
  • the jet intensity I_jet is weak, it is corrected so that the ignition energy becomes high.
  • the ignition delay timing is reduced, the combustion center of gravity is advanced, and the combustion temperature in the sub chamber 8 rises, as in the case of advancing the ignition timing.
  • the jet intensity I_jet can be increased.
  • the jet strength increase / decrease process is not limited to the above-mentioned example, and various other methods for increasing / decreasing the jet strength are applied.
  • FIG. 13 is a block diagram showing a configuration of jet strength estimation processing of the internal combustion engine control device according to the second embodiment.
  • FIG. 14 is a map showing the knock sensor amplitude reliability at the time of jet intensity estimation for each engine operating condition.
  • FIG. 15 is a diagram showing a method of estimating the jet strength by the second jet strength estimation unit of the internal combustion engine control device according to the second embodiment.
  • the parts common to the internal combustion engine control device 20 in the first embodiment are designated by the same reference numerals, and duplicate description will be omitted.
  • the internal combustion engine control device 20B includes a knock sensor signal acquisition unit 101, a bandwidth / threshold acquisition unit 102, a crank angle information acquisition unit 103, a rotation fluctuation acquisition unit 104, and an ignition time estimation unit. It has 105 and a crank shaft acceleration start time estimation unit 106. Further, the internal combustion engine control device 20B has a jet intensity comparison unit 108 and an ignition timing output unit 109. Since the configuration of these processing units is the same as that of the processing unit according to the first embodiment, the description thereof will be omitted.
  • the internal combustion engine control device 20B includes a first jet intensity estimation unit 207A, a second jet intensity estimation unit 207B, a jet intensity selection unit 201, a reliability rate ⁇ calculation unit 202, and a jet intensity upper limit value / lower limit value calculation. It has a unit 210. Since the configuration of the first jet intensity estimation unit 207A is the same as that of the jet intensity estimation unit 107 according to the first embodiment, the description thereof will be omitted. Further, the first jet intensity estimation unit 207A outputs the estimated first jet intensity to the jet intensity selection unit 201.
  • the second jet intensity estimation unit 207B is connected to the knock sensor 47 and acquires a knock sensor signal from the knock sensor 47.
  • the second jet intensity estimation unit 207B estimates the second jet intensity based on the knock sensor signal. The method of estimating the second jet intensity by the second jet intensity estimation unit 207B will be described later. Then, the second jet intensity estimation unit 207B outputs the estimated second jet intensity to the jet intensity selection unit 201.
  • the jet strength selection unit 201 is connected to the reliability rate ⁇ calculation unit 202, and the reliability rate ⁇ is output from the reliability rate ⁇ calculation unit 202. Then, the jet intensity selection unit 201 selects the jet intensity to be used as an index among the first jet intensity and the second jet intensity according to the reliability ⁇ . The jet intensity selection unit 201 outputs the selected jet intensity to the jet intensity comparison unit 108.
  • the jet intensity selection unit 201 determines that the reliability of the first jet intensity estimated by the first jet intensity estimation unit 207A is high, and selects the first jet intensity. Further, when the reliability rate ⁇ is equal to or higher than a predetermined value, the jet intensity selection unit 201 determines that the reliability of the second jet intensity estimated by the second jet intensity estimation unit 207B is high, and selects the second jet intensity.
  • the reliability rate ⁇ calculation unit 202 is connected to the accelerator opening sensor 12. Then, the throttle opening degree and the engine speed information are input from the accelerator opening degree sensor 12 to the reliability rate ⁇ calculation unit 202.
  • the reliability ⁇ calculation unit 202 has a map showing the knock sensor amplitude reliability ⁇ at the time of jet intensity estimation for each engine operating condition shown in FIG. In FIG. 14, the horizontal axis represents the engine speed [rpm], and the vertical axis represents the engine load IMEP [rpm].
  • the reliability ⁇ calculation unit 202 calculates the reliability ⁇ from the map shown in FIG. 14 based on the operating conditions of the engine, and outputs the calculation to the jet intensity selection unit 201.
  • the jet intensity upper limit value / lower limit value calculation unit 210 calculates the upper limit value and the lower limit value for the first jet intensity estimation unit 207A and the second jet intensity estimation unit 207B. That is, the jet intensity upper limit value / lower limit value calculation unit 210 calculates the upper limit value and the lower limit value according to the jet intensity selected by the jet intensity selection unit 201. Then, the jet intensity upper limit value / lower limit value calculation unit 210 outputs the calculated upper limit value and lower limit value to the jet intensity comparison unit 108.
  • the first jet intensity estimation unit 207A uses the knock sensor signal only for estimating the ignition time by the jet, and does not use the amplitude information of the knock sensor signal.
  • the amplitude information of the knock sensor signal also includes vibration at the time of ignition. Therefore, the knock sensor signal is used at low rotation where the mechanical vibration of the engine is relatively small, or at low load when the rotation fluctuation of the engine is small and the detection accuracy of the rotation fluctuation (rotation change amount ⁇ ) of the crank angle sensor 49 deteriorates.
  • the amplitude information of can be used to estimate the jet intensity.
  • the second jet intensity estimation unit 207B performs a filter process on the knock sensor signal in the same manner as the ignition time estimation unit 105, and sets the filter output value to absolute value. Convert to a value and get the amplitude of the vibration. Then, as shown in FIG. 15 (c), the second jet intensity estimation unit 207B sets the maximum amplitude value of the knock sensor signal in the range after the ignition timing and before the exhaust valve opening timing. -Estimated as kick sensor.
  • the internal combustion engine control device 20B having such a configuration can also obtain the same operation and effect as the internal combustion engine control device 20 according to the first embodiment described above.
  • the reliability of each sensor is set according to the operating state, and the sensor information used when estimating the jet intensity is determined. As a result, the performance of each sensor provided in the internal combustion engine 100 can be maximized, and the accuracy of estimating the jet strength can be improved.
  • the first jet intensity estimated by the first jet intensity estimation unit 207A and the second jet intensity estimation unit are used as the threshold value of the reliability ⁇ .
  • An example of switching between the second jet intensity estimated by the 207B and the second jet intensity has been described, but the present invention is not limited to this.
  • the jet intensities estimated by the jet intensities estimation units 207A and 207B may be weighted and the average value may be used as the jet intensities.
  • the estimation error of the jet intensity estimated from the specifications of the knock sensor 47 and the crank angle sensor 49 may be calculated in advance as the prior error distribution ⁇ , and this prior error distribution ⁇ may be used for the calculation of the reliability rate ⁇ .
  • FIG. 16 is a graph showing the correlation between the jet intensity and the initial combustion engine.
  • the horizontal axis shows the initial combustion engine (ignition timing-MFB02) obtained by a combustion analyzer based on the in-cylinder pressure of the main combustion chamber 14a.
  • the vertical axis shows the jet strength (maximum value of the differential pressure between the sub-combustion chamber and the main combustion chamber).
  • the method of estimating the jet intensity can be read as the method of estimating the initial combustion rate in jet ignition. Therefore, in the internal combustion engine control device according to the third embodiment, not only the jet intensity is estimated but also the initial combustion engine is estimated. As a result, by estimating the jet intensity, the initial combustion engine can be estimated and applied to overall engine control.
  • FIG. 17 is a diagram showing fluctuations in the in-cylinder pressure and torque of the main combustion chamber 14a in one combustion cycle.
  • the vertical axis shows the torque [Nm] and the in-cylinder pressure [MPa], and the horizontal axis shows the rotation angle of the crank shaft 48 in one combustion cycle.
  • the rotation speed change rate d ⁇ is estimated as the jet intensity.
  • the acceleration start timing of the crank shaft 48 is close to the top dead center, the combustion pressure is hardly converted into torque, and the torque value is zero. As a result, the pressure fluctuation may not be detected as the rotation fluctuation.
  • the jet intensity estimation unit 107 estimates the rotation speed change rate d ⁇ using the equation 8. After that, the jet strength estimation unit 107 calculates the in-cylinder pressure Pcomb of the main combustion chamber 14a in consideration of the pressure-torque conversion relationship by the piston mechanism based on Equation 4, and estimates the jet strength. Alternatively, the jet strength is estimated by calculating the in-cylinder pressure P comb using Equation 4 at each crank angle and calculating the slope dP / d ⁇ from the result.
  • the jet intensity estimation unit 107 uses the equation 4 only when it is determined that the jet generation timing is close to the top dead center, and the in-cylinder pressure P comb or its inclination dP / d ⁇ is used. May be calculated. As a result, the calculation load can be reduced.
  • the internal combustion engine control device 20 detects the end timing of the jet based on the crank information of the crank angle sensor 49.
  • the jet end timing is detected based on the signal of the ignition coil 16.
  • FIG. 18 is a diagram showing a state of change of the flame jet and an example of the pressure difference ⁇ P.
  • a graph of the pressure difference ⁇ P with respect to the crank angle is shown.
  • the reference numerals of explanatory views (a) to (c) showing the state of change of the flame jet shown in the upper part of FIG. 18 are added to the graph of the pressure difference ⁇ P.
  • the sub-combustion chamber is abbreviated as "sub-combustion chamber”
  • the main combustion chamber 14a is abbreviated as "main chamber”.
  • the arrows shown in the explanatory views (a) to (c) indicate the propagation direction of the flame.
  • the piston 18 begins to descend through the top dead center, but a flame is ejected from the sub-combustion chamber to the main combustion chamber 14a.
  • the pressure difference ⁇ P shows a positive value.
  • the flame jet ejected into the main combustion chamber 14a burns the air-fuel mixture in the main combustion chamber 14a, and the piston 18 descends. Then, the pressure in the sub-combustion chamber becomes a negative pressure. At this time, it can be seen from the graph at the bottom of FIG. 18 that the pressure difference ⁇ P shows a negative value. Therefore, a phenomenon occurs in which a flame blows back from the main combustion chamber 14a to the sub-combustion chamber. The fact that the blowback has occurred suggests that the jet has already ignited the air-fuel mixture in the main combustion chamber 14a. Therefore, the calculation of the rotation speed change rate d ⁇ is stopped at the time when this blowback is detected, that is, at the jet end time tburn . Therefore, the rotation speed change rate d ⁇ is calculated by the following equation 11.
  • the jet intensity estimation unit changes the rotation speed based on the rotation speed change amount ⁇ between the acceleration start time t acc or the jet start time t jet and the jet end time t burn .
  • the rate d ⁇ is calculated.
  • crank angle is 0 to 20 [deg. It falls within the range of [ATDC].
  • crank angle is 0 to 20 [deg. When the angle is retarded from the range of [ATDC], the flame does not blow back from the main combustion chamber 14a to the sub-combustion chamber because it has already entered the expansion stroke.
  • the crank angle is 0 to 20 [deg. If the angle is advanced beyond the range of [ATDC], the pressure in the engine 100 becomes too high, which is a condition outside the applicable range.
  • FIG. 19 is a first control time chart for explaining the detection of the combustion timing. Changes in the ignition signal and the secondary discharge current are shown in order from the top of FIG. The horizontal axis in FIG. 8 represents time.
  • the internal combustion engine control device outputs an ignition signal to the ignition coil 16.
  • the pulse width of the ignition signal is expressed as the charge period ct, and the primary coil is energized during the charge period ct.
  • the internal combustion engine control device controls the start of discharge of the spark plug 17 by lowering the ignition signal after the lapse of the charge period tk. In the spark plug 17, discharge is performed between the electrodes over the discharge period td.
  • the internal combustion engine control device detects the current change timing of the secondary discharge current based on the value of the secondary discharge current at the time of discharge between the electrodes fed back from the spark plug 17. Crank angle is 0 to 20 [deg.
  • the flame blowback period represented as [ATDC] the flame blows back from the main combustion chamber 14 to the sub chamber 8, so that the value of the secondary discharge current changes drastically.
  • the internal combustion engine control device detects the time when the value of the secondary discharge current changes drastically as the blowback time tburn .
  • both the start and end timings of the jet can be accurately detected, and the rotation speed change rate d ⁇ is brought closer to the actual rotation speed behavior. Can be done. As a result, the accuracy of estimating the jet strength can be improved.
  • FIG. 20 is a schematic configuration diagram showing an enlarged configuration around the auxiliary chamber of the internal combustion engine according to the modified example.
  • the internal combustion engine 100 shown in FIG. 1 is a passive internal combustion engine in which an injector 13 is provided on a side surface of a cylinder 14 and only a spark plug 17 is installed in an auxiliary chamber 8.
  • the internal combustion engine to which the internal combustion engine control device of the present invention is applied is not limited to the passive type shown in FIG.
  • an active type internal combustion engine in which the injector 13C is installed in the sub chamber 8 as shown in FIG. 20 may be applied. Then, the injector 13C directly injects fuel into the sub chamber 8.
  • the air-fuel ratio in the sub chamber 8 is controlled so that the ignitability is good by the air supplied from the main combustion chamber 14a side through the sub chamber injection hole 8a and the fuel supplied from the injector 13C. Can be done. As a result, it becomes possible to improve the combustion rest.
  • each of the above-described embodiments describes the configurations of the apparatus and the system in detail and concretely in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to those including all the described configurations. Further, it is possible to replace a part of the configuration of the embodiment described here with the configuration of another embodiment, and further, it is possible to add the configuration of another embodiment to the configuration of one embodiment. It is possible. It is also possible to add, delete, or replace a part of the configuration of each embodiment with another configuration.
  • control lines and information lines indicate what is considered necessary for explanation, and not all control lines and information lines are necessarily shown on the product. In practice, it can be considered that almost all configurations are interconnected.

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Abstract

La présente invention concerne un dispositif de commande de moteur à combustion interne qui comprend : une unité d'estimation de temps d'allumage, une unité d'acquisition d'informations d'angle de vilebrequin, une unité d'acquisition de fluctuation de rotation et une unité d'acquisition d'intensité de jet. L'unité d'estimation de temps d'allumage estime un temps d'allumage sur la base d'un signal de capteur de cliquetis détecté par un capteur de cliquetis. L'unité d'acquisition de fluctuation de rotation calcule, sur la base d'informations d'angle de vilebrequin, une variation de vitesse de rotation qui est générée plus tard que le temps d'allumage. L'unité d'estimation d'intensité de jet calcule un taux de variation de vitesse de rotation qui est généré plus tard que le temps d'allumage sur la base de la variation de vitesse de rotation calculée par l'unité d'acquisition de fluctuation de rotation et du temps d'allumage estimé par l'unité d'estimation de temps d'allumage, et estime l'intensité de jet.
PCT/JP2021/035058 2021-01-12 2021-09-24 Dispositif de commande de moteur à combustion interne WO2022153611A1 (fr)

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CN202180077865.6A CN116472399A (zh) 2021-01-12 2021-09-24 内燃机控制装置

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JP2021002610A JP7393368B2 (ja) 2021-01-12 2021-01-12 内燃機関制御装置

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JP2007170405A (ja) * 2001-03-30 2007-07-05 Mitsubishi Heavy Ind Ltd 内燃機関の燃焼診断・制御装置及び燃焼診断・制御方法
JP2017120035A (ja) * 2015-12-28 2017-07-06 川崎重工業株式会社 ガスエンジンシステム
JP2018178966A (ja) * 2017-04-21 2018-11-15 株式会社デンソー 内燃機関の制御装置および内燃機関の制御方法

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JP6630576B2 (ja) 2016-01-21 2020-01-15 三菱重工エンジン＆ターボチャージャ株式会社 副室式ガスエンジン及びその運転制御方法
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JP2007170405A (ja) * 2001-03-30 2007-07-05 Mitsubishi Heavy Ind Ltd 内燃機関の燃焼診断・制御装置及び燃焼診断・制御方法
JP2017120035A (ja) * 2015-12-28 2017-07-06 川崎重工業株式会社 ガスエンジンシステム
JP2018178966A (ja) * 2017-04-21 2018-11-15 株式会社デンソー 内燃機関の制御装置および内燃機関の制御方法

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