WO2013038805A1 - Dispositif de commande de combustion - Google Patents

Dispositif de commande de combustion Download PDF

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Publication number
WO2013038805A1
WO2013038805A1 PCT/JP2012/068337 JP2012068337W WO2013038805A1 WO 2013038805 A1 WO2013038805 A1 WO 2013038805A1 JP 2012068337 W JP2012068337 W JP 2012068337W WO 2013038805 A1 WO2013038805 A1 WO 2013038805A1
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WO
WIPO (PCT)
Prior art keywords
fuel injection
pressure
air
fuel
intake pressure
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Application number
PCT/JP2012/068337
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English (en)
Japanese (ja)
Inventor
裕史 葛山
謹 河合
Original Assignee
株式会社豊田自動織機
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Publication of WO2013038805A1 publication Critical patent/WO2013038805A1/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
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/30—Controlling fuel injection
    • F02D41/38—Controlling fuel injection of the high pressure type
    • F02D41/40—Controlling fuel injection of the high pressure type with means for controlling injection timing or duration
    • F02D41/401—Controlling injection timing
    • 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
    • F02D41/0025—Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
    • F02D41/0047—Controlling exhaust gas recirculation [EGR]
    • F02D41/005—Controlling exhaust gas recirculation [EGR] according to engine operating conditions
    • F02D41/0052—Feedback control of engine parameters, e.g. for control of air/fuel ratio or intake air amount
    • 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
    • F02D41/30—Controlling fuel injection
    • F02D41/38—Controlling fuel injection of the high pressure type
    • F02D41/40—Controlling fuel injection of the high pressure type with means for controlling injection timing or duration
    • F02D41/402—Multiple injections
    • 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
    • F02B1/00—Engines characterised by fuel-air mixture compression
    • F02B1/12—Engines characterised by fuel-air mixture compression with compression ignition
    • 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
    • F02B2275/00—Other engines, components or details, not provided for in other groups of this subclass
    • F02B2275/14—Direct injection into combustion chamber
    • 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
    • F02B29/00—Engines characterised by provision for charging or scavenging not provided for in groups F02B25/00, F02B27/00 or F02B33/00 - F02B39/00; Details thereof
    • F02B29/04—Cooling of air intake supply
    • F02B29/0406—Layout of the intake air cooling or coolant circuit
    • 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
    • F02D2200/04—Engine intake system parameters
    • F02D2200/0406—Intake manifold pressure
    • 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
    • F02D41/30—Controlling fuel injection
    • F02D41/3011—Controlling fuel injection according to or using specific or several modes of combustion
    • F02D41/3017—Controlling fuel injection according to or using specific or several modes of combustion characterised by the mode(s) being used
    • F02D41/3035—Controlling fuel injection according to or using specific or several modes of combustion characterised by the mode(s) being used a mode being the premixed charge compression-ignition mode
    • 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
    • F02D41/30—Controlling fuel injection
    • F02D41/38—Controlling fuel injection of the high pressure type
    • F02D41/3809—Common rail control systems
    • F02D41/3836—Controlling the fuel pressure
    • F02D41/3845—Controlling the fuel pressure by controlling the flow into the common rail, e.g. the amount of fuel pumped
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
    • F02M26/02—EGR systems specially adapted for supercharged engines
    • F02M26/04—EGR systems specially adapted for supercharged engines with a single turbocharger
    • F02M26/05—High pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust system upstream of the turbine and reintroduced into the intake system downstream of the compressor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
    • F02M26/13—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories
    • F02M26/22—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories with coolers in the recirculation passage
    • F02M26/23—Layout, e.g. schematics
    • F02M26/25—Layout, e.g. schematics with coolers having bypasses
    • 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
    • Y02T10/12—Improving ICE efficiencies
    • 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 a combustion control device for an engine that performs Premixed Charge Compression Ignition (PCCI) combustion.
  • PCCI Premixed Charge Compression Ignition
  • a combustion control device for an engine that performs premixed compression ignition combustion for example, a combustion control device described in Patent Document 1 is known.
  • the combustion control device described in Patent Document 1 forms the mixture as homogeneous as possible in advance by injecting fuel several times by the injector from the middle stage to the late stage of the compression stroke of the cylinder, and then mixes the mixture by self-ignition. Burn it.
  • An object of the present invention is to provide a combustion control device capable of realizing appropriate premixed compression ignition combustion even when the intake pressure into the combustion chamber decreases.
  • the present invention is a combustion control device of an engine performing premixed compression ignition combustion, comprising: a fuel injection valve for injecting fuel into a combustion chamber of the engine; determination means for determining a fuel injection amount and a fuel injection timing; In order to carry out fuel injection according to the amount and fuel injection timing, injection control means for controlling the fuel injection valve, an intake passage for drawing air into the combustion chamber, and exhaust gas after combustion from the combustion chamber
  • injection control means for controlling the fuel injection valve, an intake passage for drawing air into the combustion chamber, and exhaust gas after combustion from the combustion chamber
  • the ignition timing by fuel injection is advanced when the intake pressure detected by the intake pressure detection means for detecting the intake pressure into the combustion chamber and the intake pressure detected by the intake pressure detection means is lower than a predetermined pressure.
  • correction means for correcting the
  • the combustion control device of the present invention detects the intake pressure into the combustion chamber, and corrects the ignition timing by fuel injection to advance when the intake pressure is lower than a predetermined pressure.
  • the combustion waveform when the intake pressure is lower than the predetermined pressure approaches the combustion waveform obtained when the intake pressure is the predetermined pressure. Therefore, appropriate premixed compression ignition combustion is realized. As a result, it is possible to suppress an increase in combustion noise and a deterioration in emission.
  • the low temperature oxidation reaction (cold flame reaction) in which heat generation gradually occurs by the fuel injected into the combustion chamber and the high temperature oxidation reaction (thermal And flame reaction).
  • the ignition timing by fuel injection is a timing at which a high temperature oxidation reaction starts to rapidly generate heat.
  • the determination means determines the fuel injection amount and fuel injection timing of the second fuel injection to be performed after the first fuel injection and the first fuel injection, and the injection control means determines the fuel injection amount and the fuel injection timing. Accordingly, the fuel injection valve is controlled such that the first fuel injection and the second fuel injection are sequentially performed, and the correction means detects that the intake pressure detected by the intake pressure detection means is lower than a predetermined pressure, The correction may be made to advance the ignition timing by the first fuel injection.
  • the correction means corrects to advance the ignition timing by the first fuel injection when the detected intake pressure is lower than a predetermined pressure.
  • the combustion waveform when the intake pressure is lower than the predetermined pressure approaches the combustion waveform obtained when the intake pressure is the predetermined pressure.
  • the first fuel injection and the second fuel injection are divided injections of the main fuel injection for generating the required engine output, and a small amount of fuel injection performed before the main fuel injection This is different from (so-called pilot fuel injection or pre-fuel injection etc).
  • the correction means includes an air-fuel ratio control means for controlling an air-fuel ratio in the combustion chamber, and an injection timing advance means for advancing the fuel injection timing of the first fuel injection determined by the determination means.
  • the advance means advances the fuel injection timing of the first fuel injection when the intake pressure detected by the intake pressure detection means is lower than a predetermined pressure
  • the air fuel ratio control means detects the intake pressure by the intake pressure detection means When the intake pressure is lower than the predetermined pressure, the air-fuel ratio in the combustion chamber may be controlled to be maintained at the air-fuel ratio at the predetermined pressure.
  • the injection timing advance means advances the fuel injection timing of the first fuel injection, the ignition timing by the first fuel injection is advanced.
  • the ignition timing by the first fuel injection reliably approaches the ignition timing obtained when the intake pressure is a predetermined pressure.
  • the air-fuel ratio control means controls the air-fuel ratio in the combustion chamber to be maintained at the air-fuel ratio at the predetermined pressure, the combustion waveform approaches the combustion waveform obtained when the intake pressure is the predetermined pressure. As a result, the combustion of the premixed mixture of fuel and air is properly performed, and the increase in HC and CO of unburned components can be suppressed.
  • the engine further includes load detecting means for detecting the load of the engine, and the injection timing advancing means has the intake pressure detected by the intake pressure detecting means lower than a predetermined pressure and the engine load detected by the load detecting means is When it is higher than the first predetermined value, the fuel injection timing of the first fuel injection is advanced, and the air-fuel ratio control means determines that the intake pressure detected by the intake pressure detection means is lower than the predetermined pressure and When the load of the engine detected by the load detection means is higher than the first predetermined value, the air-fuel ratio in the combustion chamber may be controlled to be maintained at the air-fuel ratio at the predetermined pressure.
  • the ignition timing by the first fuel injection is less likely to be advanced even if the fuel injection timing of the first fuel injection is advanced. Therefore, the correction by the injection timing advancing means and the air fuel ratio control means (the fuel injection timing of the first fuel injection is advanced and controlled so that the air fuel ratio in the combustion chamber is maintained at the air fuel ratio at the predetermined pressure) As a result, the operating range in which the correction for advancing the ignition timing by the first fuel injection is performed is narrowed to the area of the engine load where it is easy to advance the ignition timing by the first fuel injection. Thereby, the ignition timing by the first fuel injection can be efficiently brought close to the ignition timing obtained when the intake pressure is a predetermined pressure.
  • the air fuel ratio control means When the intake pressure detected by the intake pressure detection means is lower than a predetermined pressure and the load of the engine detected by the load detection means is lower than a first predetermined value, the air fuel ratio control means The air-fuel ratio may be controlled to be lean with respect to the air-fuel ratio at a predetermined pressure.
  • the air-fuel ratio control means controls the air-fuel ratio in the combustion chamber to be lean with respect to the air-fuel ratio at the predetermined pressure.
  • the amount of air taken into the combustion chamber is sufficiently increased, so that the ignition timing by the first fuel injection is advanced even if the fuel injection timing of the first fuel injection is not particularly advanced. Therefore, the combustion waveform surely approaches the combustion waveform obtained when the intake pressure is a predetermined pressure. As a result, the combustion of the premixed mixture of fuel and air is properly performed, and the increase in unburned HC and CO can be suppressed.
  • the correction means is configured to set the fuel injection pressure of the first fuel injection and the second fuel injection when the engine load detected by the load detection means is higher than a second predetermined value larger than the first predetermined value. It may further include injection pressure control means for controlling to decrease.
  • the injection pressure control means controls to lower the fuel injection pressure of the first fuel injection and the second fuel injection when the load of the engine is higher than a second predetermined value larger than the first predetermined value. Therefore, the second fuel injection hardly causes ignition. Therefore, the premixing time of the fuel and air by the second fuel injection becomes long, and the insufficient premixing is prevented. As a result, an increase in smoke can be suppressed.
  • the correction means reduces injection amount of the second fuel injection when the engine load detected by the load detection means is higher than a second predetermined value larger than the first predetermined value. May further be included.
  • the injection amount reducing means reduces the fuel injection amount of the second fuel injection when the load of the engine is higher than the second predetermined value larger than the first predetermined value
  • the injection pressure control means reduces the second Similar to the case of reducing the fuel injection pressure of the fuel injection, the second fuel injection hardly causes the ignition. Therefore, the premixing time of fuel and air is prolonged, and the lack of premixing is prevented. As a result, an increase in smoke can be suppressed.
  • the exhaust gas recirculation passage is disposed to connect the exhaust gas passage and the intake gas passage, and is disposed in an exhaust gas recirculation passage for recirculating a portion of the exhaust gas as exhaust gas recirculation gas into the combustion chamber.
  • the air-fuel ratio control means may control the air-fuel ratio in the combustion chamber by controlling the valve means such that the amount of recirculation of the exhaust gas recycle is reduced. .
  • valve means for adjusting the amount of recirculation of the exhaust gas recirculation is used, the air-fuel ratio in the combustion chamber can be maintained at the air-fuel ratio at the predetermined pressure with a simple configuration and with certainty.
  • FIG. 1 is a schematic configuration view showing a diesel engine provided with a combustion control device according to an embodiment of the present invention.
  • FIG. 2 is a flowchart showing a processing procedure executed by the ECU shown in FIG.
  • FIG. 3 is a graph showing the heat release rate waveform under the condition where the engine load is in the low load region.
  • FIG. 4 is a graph showing the level of combustion noise and the emission concentration of HC and CO under the condition where the engine load is in the low load region.
  • FIG. 5 is a graph showing the heat release rate waveform under the condition where the engine load is in the medium load region.
  • FIG. 6 is a graph showing the amount of generated NOx and the level of combustion noise under the condition where the engine load is in the medium load region.
  • FIG. 1 is a schematic configuration view showing a diesel engine provided with a combustion control device according to an embodiment of the present invention.
  • FIG. 2 is a flowchart showing a processing procedure executed by the ECU shown in FIG.
  • FIG. 3 is a
  • FIG. 7 is a graph showing the heat release rate waveform under the condition where the engine load is in the high load region.
  • FIG. 8 is a graph showing the smoke generation rate and the pre-mixing time by the second fuel injection under the condition where the engine load is in the high load range.
  • FIG. 9 shows the characteristics of the combustion waveform when only the fuel injection timing of the first fuel injection is advanced, and the case where the fuel injection timing of the first fuel injection and the second fuel injection are advanced. Of the characteristics of the combustion waveform of
  • FIG. 1 is a schematic configuration view showing a diesel engine provided with a combustion control device according to an embodiment of the present invention.
  • the diesel engine 1 is a four-cylinder in-line diesel engine that performs homogeneous charge compression ignition (PCCI), and includes a common rail fuel injection device.
  • the diesel engine 1 comprises an engine body 2 in which four cylinders 3 are arranged.
  • Each cylinder 3 is provided with an injector (fuel injection valve) 5 for injecting fuel into the combustion chamber 4.
  • the injectors 5 inject fuel radially from the injection nozzle 5a.
  • Each injector 5 is connected to the common rail 6.
  • the common rail 6 is connected to the high pressure pump 8 through the fuel supply pipe 7.
  • the common rail 6 stores high pressure fuel supplied from the high pressure pump 8 and uniformly supplies the fuel to each injector 5.
  • a rail pressure adjusting valve 9 is disposed in the fuel supply pipe 7 to adjust the pressure of the fuel in the common rail 6 (common rail pressure).
  • An intake passage 10 for drawing air into the combustion chamber 4 is connected to the engine body 2 via an intake manifold 11.
  • An exhaust passage 12 for discharging exhaust gas after combustion is connected to the engine body 2 via an exhaust manifold 13.
  • an air cleaner 14, a compressor 16 of a turbocharger 15, an intercooler 17, and a throttle valve 18 are disposed from the upstream side toward the downstream side.
  • the throttle valve 18 reduces the passage area of the intake passage 10.
  • a negative pressure is generated downstream of the throttle valve 18. This enables exhaust gas recirculation (EGR) described later.
  • EGR exhaust gas recirculation
  • the turbine 19 of the turbocharger 15 and the DPF 20 with a catalyst are disposed.
  • the diesel engine 1 includes an exhaust gas recirculation (EGR) device 21 that recirculates a part of the exhaust gas after combustion into the combustion chamber 4 as an exhaust gas recirculation gas (EGR gas).
  • the EGR device 21 is arranged to connect the intake passage 10 and the exhaust manifold 13.
  • the EGR device 21 has an EGR passage 22, an EGR valve (valve means) 23, an EGR cooler 24, a bypass passage 25, and a switching valve 26.
  • the EGR passage 22 connects the intake passage 10 and the exhaust manifold 13 to recirculate the EGR gas.
  • the EGR valve 23 adjusts the amount of recirculation of EGR gas from the exhaust manifold 13 to the intake passage 10.
  • the EGR cooler 24 cools the EGR gas passing through the EGR passage 22.
  • the bypass passage 25 is connected to the EGR passage 22 so as to bypass the EGR cooler 24.
  • the switching valve 26 switches the flow path of the EGR gas to the EGR cooler 24 side or the bypass passage 25 side.
  • Each of the injectors 5, the rail pressure adjustment valve 9, the throttle valve 18, the EGR valve 23, and the switching valve 26 described above are controlled by an electronic control unit (ECU) (controller) 27.
  • ECU electronice control unit
  • a crank angle sensor 28, an accelerator opening sensor 29, and an intake pressure sensor 30 are connected to the ECU 27.
  • the crank angle sensor 28 detects a rotation angle (crank angle) of a crankshaft to which a piston (not shown) is connected. Based on the output from the crank angle sensor 25, the number of rotations of the engine body 2 (engine rotation number) can be calculated.
  • the accelerator opening degree sensor 29 detects the depression angle (accelerator opening degree) of the accelerator pedal as an alternative value of the load (engine load) of the engine body 2.
  • the accelerator opening degree sensor 29 functions as a load sensor (load detection means). In a diesel engine equipped with a common rail fuel injection system, the fuel injection amount is electronically controlled, and it is also possible to use the fuel injection amount as a substitute value for the engine load.
  • the intake pressure sensor 30 detects the pressure of air taken into the combustion chamber 4 (intake pressure into the combustion chamber 4). The intake pressure sensor 30 functions as an intake pressure detection unit.
  • the intake pressure sensor 30 is disposed, for example, at the downstream end of the intake passage 10.
  • Detection signals of the crank angle sensor 28, the accelerator opening degree sensor 29, and the intake pressure sensor 30 are input to the ECU 27.
  • the ECU 27 performs predetermined processing, and controls the injector 5, the rail pressure adjustment valve 9, the throttle valve 18, the EGR valve 23, and the switching valve 26.
  • the combustion control apparatus 31 of the form is comprised.
  • the combustion control device 31 sucks air into the combustion chamber 4 and injects the fuel from the injectors 5 into the combustion chamber 4 in multiple cycles in one cycle of the intake stroke, compression stroke, expansion stroke, and exhaust stroke. (Divided injection) is controlled to perform premixed compression ignition combustion.
  • FIG. 2 is a flowchart showing the processing procedure executed by the ECU 27.
  • the injector 5, the rail pressure adjusting valve 9, and the EGR valve 23 are controlled based on the detection signals of the sensors 28-30.
  • the ECU 27 first determines the fuel injection amount and fuel injection timing of the second fuel injection performed after the first fuel injection and the first fuel injection (S101).
  • the ECU 27 determines the fuel injection amount and the fuel injection timing based on the engine speed detected by the crank angle sensor 28 and the accelerator opening (engine load) detected by the accelerator opening sensor 29. Do.
  • the ECU 27 determines whether the intake pressure detected by the intake pressure sensor 30 is lower than a reference pressure (for example, the atmospheric pressure) (S102). If the ECU 27 determines that the intake pressure is lower than the reference pressure, the ECU 27 determines whether the engine load detected by the accelerator opening sensor 29 is lower than the low load threshold (S103).
  • the low load side threshold is set to, for example, an opening of 30% with respect to the accelerator fully open. The ECU 27 may determine whether the engine load detected by the accelerator opening sensor 29 is less than or equal to the low load threshold value in the process of S103.
  • the air-fuel ratio (A / F) in the combustion chamber 4 at that time is made lean with respect to the air-fuel ratio set at the reference pressure. In other words, control is performed to become larger than the air-fuel ratio set at the reference pressure (S104).
  • the ECU 27 controls the air-fuel ratio by controlling the EGR valve 23. Specifically, the ECU 27 increases the amount of intake air into the combustion chamber 4 by controlling the EGR valve 23 so as to reduce the amount of recirculation of EGR gas to the intake passage 10.
  • the air-fuel ratio is made lean by increasing the amount of intake air into the combustion chamber 4 without changing the fuel injection amount into the combustion chamber 4.
  • the amount to make the air-fuel ratio lean may be increased, for example, as the intake pressure and the engine load are lower.
  • the ECU 27 determines that the engine load is not lower than the low load threshold, the ECU 27 controls the air-fuel ratio in the combustion chamber 4 at that time to be maintained at the air-fuel ratio set at the reference pressure (S105) .
  • the ECU 27 controls the air-fuel ratio by controlling the EGR valve 23.
  • the ECU 27 controls the EGR valve 23 to reduce the amount of EGR gas recirculated to the intake passage 10 in accordance with the decrease in the amount of intake air. As a result, the amount of intake air into the combustion chamber 4 increases, and the air-fuel ratio is maintained at the air-fuel ratio set at the reference pressure.
  • the ECU 27 advances the fuel injection timing of the first fuel injection and the second fuel injection determined by the processing in S101 (S106).
  • the amount of advance of the fuel injection timing may be, for example, an amount according to the intake pressure and the engine load, or may be a predetermined constant amount.
  • the ignition timing of the premixed mixture of air and fuel is advanced.
  • the ECU 27 determines whether the engine load detected by the accelerator opening sensor 29 is higher than the high load threshold (S107).
  • the high load side threshold value is a value larger than the low load side threshold value, and is set to, for example, an opening degree of 60% with respect to full accelerator opening.
  • the ECU 27 determines that the engine load is higher than the high load threshold value, the ECU 27 controls the rail pressure adjusting valve 9 so as to reduce the common rail pressure from a preset value (S108). As a result, the fuel injection pressure from the injector 5 is reduced.
  • the amount of reduction of the common rail pressure may be, for example, an amount corresponding to the intake pressure and the engine load, or may be a preset fixed amount.
  • the ECU 27 decreases the fuel injection amount of the second fuel injection determined by the processing in S101, and the fuel injection amount of the first fuel injection determined in S101 by the reduction amount of the fuel injection amount.
  • the amount is increased (S109).
  • the amount of decrease of the fuel injection amount may be, for example, an amount according to the intake pressure and the engine load, or may be a preset constant amount.
  • each injector 5 is controlled so that the first fuel injection and the second fuel injection are sequentially performed (S110).
  • the ECU 27 determines that the intake pressure is not lower than the reference pressure based on the process of S102, or when the process of S104 is performed, the fuel injection amount and the fuel injection determined by the process of S101 The first fuel injection and the second fuel injection are sequentially performed according to the timing.
  • the ECU 27 determines that the engine load is not higher than the high load threshold based on the processing at S107, the fuel injection amount determined by the processing at S101 and the fuel injection timing corrected by the processing at S106
  • the first fuel injection and the second fuel injection are sequentially performed according to
  • the ECU 27 performs the first fuel injection and the second fuel injection according to the fuel injection amount corrected by the process of S109 and the fuel injection timing determined by the process of S101. Implement sequentially.
  • the ECU 27 (in particular, the process in S101) constitutes a determination means for determining the fuel injection amount and the fuel injection timing.
  • the ECU 27 (in particular, the process at S110) constitutes an injection control means for controlling the fuel injection valve (injector 5) so as to carry out the fuel injection according to the fuel injection amount and the fuel injection timing.
  • the ECU 27 (particularly, the processing in S102 to S109) corrects the ignition timing by fuel injection to advance when the intake pressure detected by the intake pressure detection means (intake pressure sensor 30) is lower than a predetermined pressure. Constitute correction means.
  • the ECU 27 (particularly, the processing in S102 to S105) constitutes an air-fuel ratio control unit that controls the air-fuel ratio in the combustion chamber 4.
  • the ECU 27 (in particular, the process at S106) constitutes an injection timing advancing means for advancing the fuel injection timing of the first fuel injection determined by the determining means.
  • the ECU 27 (in particular, the processing in S107 and S108) is executed when the engine load detected by the load detection means (the accelerator opening sensor 29) is higher than a second predetermined value larger than the first predetermined value.
  • An injection pressure control means is configured to perform control to lower the fuel injection pressure of the first fuel injection and the second fuel injection.
  • the ECU 27 (in particular, the processing in S107 and S109) is performed when the engine load detected by the load detection means (the accelerator opening sensor 29) is higher than a second predetermined value larger than the first predetermined value.
  • the fuel injection amount reducing means is configured to reduce the fuel injection amount of the second fuel injection.
  • the engine load when the intake pressure into the combustion chamber 4 is lower than the reference pressure, the engine load is in the middle load range from the low load threshold to the high load threshold.
  • the air-fuel ratio set at the reference pressure is maintained so as to secure the intake air amount of 1 and the fuel injection timing of the first fuel injection and the second fuel injection is advanced.
  • the ignition timing of the premixed mixture of fuel and air substantially matches the ignition timing when the intake pressure is the reference pressure, so a heat release rate waveform is obtained when the intake pressure is the reference pressure It approaches the heat release rate waveform. Since the combustion of the premixed mixture is properly performed, it is possible to suppress an increase in combustion noise and an increase in HC and CO of unburned components. NOx can be reduced as compared with the case where the air-fuel ratio in the combustion chamber 4 is made lean.
  • the amount of intake air into the combustion chamber 4 can be secured under the condition that the engine load is in the high load region higher than the high load threshold.
  • the air-fuel ratio set at the time of the reference pressure is maintained, and the fuel injection timing of the first fuel injection and the second fuel injection is advanced.
  • the common rail pressure is reduced, the fuel injection pressure from the injector 5 is reduced, and the fuel injection amount of the second fuel injection is reduced.
  • the heat release rate waveform approaches the heat release rate waveform obtained when the intake pressure is the reference pressure.
  • the ignition by the first fuel injection is delayed, so the temperature (in-cylinder temperature) in the combustion chamber 4 rises when the second fuel injection is performed.
  • the amount of fuel injected by the first fuel injection increases, so the temperature in the combustion chamber 4 further increases when the second fuel injection is performed. easy. Therefore, the ignitability of the fuel by the second fuel injection is improved, and the ignition delay by the second fuel injection is easily shortened.
  • the fuel injection pressure from the injector 5 is reduced and the fuel injection amount of the second fuel injection is reduced, shortening of the ignition delay due to the second fuel injection can be suppressed. Therefore, the pre-mixing time by the second fuel injection becomes longer, and the insufficient pre-mixing of fuel and air is prevented. As a result, an increase in smoke can be suppressed.
  • the ignitability of the premixed mixture of fuel and air is poor.
  • the intake pressure into the combustion chamber 4 is low, the first fuel injection is carried out at an early stage where the pressure in the combustion chamber 4 (in-cylinder pressure) is low.
  • the air-fuel ratio set at the reference pressure is maintained so that the amount of intake air into the combustion chamber 4 is maintained, and the fuel injection timing of the first fuel injection and the second fuel injection is
  • the advance angle is advanced, the first fuel injection is performed at a stage where the in-cylinder pressure is lower. In this case, the spray travel distance of the fuel is extended, and the amount of spray adhering to the wall surface of the combustion chamber 4 is large. For this reason, the inhibitory effect of HC and CO increase may fall.
  • the air-fuel ratio in the combustion chamber 4 is set at the reference pressure under a condition where the engine load is in the low load region lower than the low load threshold. It is made lean with respect to the air fuel ratio.
  • the amount of air taken into the combustion chamber 4 is sufficiently large, and the ignition timing of the premixed mixture of fuel and air is earlier even if the fuel injection timing of the first fuel injection is not advanced. Therefore, the ignition timing of the premixed gas substantially coincides with the ignition timing when the intake pressure is the reference pressure, and the heat release rate waveform approaches the heat release rate waveform obtained when the intake pressure is the reference pressure. . Therefore, the combustion of the premixed gas is properly performed, and it is possible to suppress an increase in combustion noise and an increase in HC and CO of unburned components.
  • FIG. 3 is a graph showing an example of a heat release rate waveform under a situation where the engine load is in a low load region.
  • a plurality of heat release rate waveforms obtained under various conditions are shown.
  • the broken line P represents the heat release rate waveform when the intake pressure is the reference pressure.
  • the thin solid line Q represents the heat release rate waveform when the intake pressure is lower than the reference pressure by 20 kPa.
  • a thick solid line R represents a heat generation rate waveform when the air fuel ratio is made lean with respect to the air fuel ratio when the intake pressure is lower than the reference pressure by 20 kPa and the intake pressure is the reference pressure.
  • the ignition delay causes the heat release rate waveform to deviate significantly from the heat release rate waveform when the intake pressure is the reference pressure (broken line P and fine See solid line Q).
  • the air release ratio is made lean with respect to the air-fuel ratio when the intake pressure is the reference pressure, whereby the heat release rate waveform is the intake pressure being the reference pressure It approaches the heat release rate waveform of time (see the broken line P and the thick solid line R).
  • FIG. 4 is a graph showing an example of the level of combustion noise and the emission concentration of HC and CO under a situation where the engine load is in a low load region.
  • FIG. 4 shows an example of the level of combustion noise and the emission concentration of HC and CO under the same conditions as the conditions under which the plurality of heat release rate waveforms shown in FIG. 3 were obtained.
  • P ref reference pressure
  • the air-fuel ratio is made lean relative to the air-fuel ratio when the intake pressure is the reference pressure (P ref )
  • the level of combustion noise and the generation rates of HC and CO hardly change compared to when the intake pressure is the reference pressure (P ref ).
  • the exhaust concentration of HC and CO is sufficiently lower than the case where the intake pressure is 20 kPa lower than the reference pressure (P ref ) and the air fuel ratio is not leaned.
  • FIG. 5 is a graph showing an example of the heat release rate waveform under the condition that the engine load is in the medium load region. Also in FIG. 5, a plurality of heat release rate waveforms obtained under various conditions are shown.
  • the broken line P represents the heat release rate waveform when the intake pressure is the reference pressure.
  • An alternate long and short dash line Q represents a heat release rate waveform when the intake pressure is lower than the reference pressure by 20 kPa.
  • the thin solid line R represents the heat release rate waveform when the air fuel ratio is made lean with respect to the air fuel ratio when the intake pressure is lower than the reference pressure by 20 kPa and the intake pressure is the reference pressure.
  • a thick solid line S represents a heat release rate waveform when the intake pressure is lower than the reference pressure by 20 kPa and the fuel injection timing of the first fuel injection and the second fuel injection is advanced.
  • FIG. 6 is a graph showing an example of the amount of generated NOx and the level of combustion noise in a situation where the engine load is in the medium load region.
  • FIG. 6 shows the generation amount of NOx and the level of combustion noise under the same conditions as the conditions under which the plurality of heat release rate waveforms shown in FIG. 5 were obtained.
  • P ref reference pressure
  • FIG. 6 even if the intake pressure is lower than the reference pressure (P ref ) by 20 kPa, the fuel injection timing is advanced, so that the combustion noise level is equal to the reference pressure (P ref ). It hardly changes compared to when.
  • FIG. 7 is a graph showing an example of the heat release rate waveform under the condition where the engine load is in the high load region. Also shown in FIG. 7 are multiple heat release rate waveforms under various conditions.
  • the broken line P represents the heat release rate waveform when the intake pressure is the reference pressure.
  • An alternate long and short dash line Q represents a heat release rate waveform when the intake pressure is lower than the reference pressure by 30 kPa.
  • a thin solid line R represents a heat release rate waveform when the fuel injection timing of the first fuel injection and the second fuel injection is advanced when the intake pressure is lower than the reference pressure by 30 kPa.
  • the intake pressure is lower than the reference pressure by 30 kPa, in addition to the advance angle of the fuel injection timing of the first fuel injection and the second fuel injection, the common rail pressure is reduced and the second It represents the heat release rate waveform when the fuel injection amount of the fuel injection is reduced.
  • FIG. 8 is a graph showing an example of the smoke generation rate and the premixing time by the second fuel injection under a situation where the engine load is in the high load range.
  • FIG. 8 shows the smoke generation rate and the premixing time by the second fuel injection under the same conditions as the conditions under which the plurality of heat release rate waveforms shown in FIG. 7 were obtained.
  • P ref reference pressure
  • the common rail pressure is reduced in addition to the advance of the fuel injection timing, and the fuel injection amount for the second fuel injection
  • the smoke generation rate hardly changes compared to when the intake pressure is the reference pressure (P ref ).
  • the premixing time by the second fuel injection is longer than when the processing is not performed, The incidence of smoke is low.
  • the combustion waveform by the first fuel injection and the intake pressure become the reference pressure regardless of the engine load. It approaches the combustion waveform when it is.
  • substantially the same premixed compression ignition combustion is realized as when the intake pressure is the reference pressure.
  • the present embodiment is a combustion control device for an engine that performs premixed compression ignition combustion, including a fuel injection valve that injects fuel into a combustion chamber of the engine, and intake air for drawing air into the combustion chamber.
  • the fuel cell system includes a passage, an exhaust passage for discharging exhaust gas after combustion from the combustion chamber, an intake pressure sensor for detecting an intake pressure into the combustion chamber, and a controller for operating a fuel injection valve.
  • the fuel injection valve is operated to determine the injection amount and the fuel injection timing, and the fuel injection is performed according to the determined fuel injection amount and the fuel injection timing, and the intake pressure detected by the intake pressure sensor is higher than a predetermined pressure When it is low, correction is made to advance the ignition timing by fuel injection.
  • the controller determines a fuel injection amount and a fuel injection timing of the second fuel injection to be performed after the first fuel injection and the first fuel injection, and the first according to the determined fuel injection amount and the fuel injection timing.
  • the fuel injection valve is operated so that the second fuel injection and the second fuel injection are sequentially performed, and when the intake pressure detected by the intake pressure sensor is lower than the predetermined pressure, the ignition timing by the first fuel injection It may be corrected to advance the
  • the controller advances the fuel injection timing of the first fuel injection when the intake pressure detected by the intake pressure sensor is lower than the predetermined pressure, and sets the air-fuel ratio in the combustion chamber to the air-fuel ratio at the predetermined pressure. It may be controlled to maintain.
  • the combustion control device further includes a load sensor for detecting a load of the engine, and the controller is configured to set an engine load detected by the load sensor at a lower intake pressure detected by the intake pressure sensor than the predetermined pressure.
  • the fuel injection timing of the first fuel injection may be advanced to maintain the air-fuel ratio in the combustion chamber at the air-fuel ratio at the predetermined pressure.
  • the controller determines the air fuel ratio in the combustion chamber Control may be performed to make the air-fuel ratio lean at a predetermined pressure.
  • the combustion control device is disposed to connect the exhaust passage and the intake passage, and is disposed in an exhaust gas recirculation passage for recirculating a portion of the exhaust gas as exhaust gas recirculation gas into the combustion chamber, and disposed in the exhaust gas recirculation passage.
  • the air-fuel ratio in the combustion chamber may be controlled by further comprising a valve for adjusting the amount of recirculation of the circulating gas, and the controller controls the valve so as to reduce the amount of recirculation of the exhaust gas recirculation.
  • the controller reduces the fuel injection pressure of the first fuel injection and the second fuel injection when the engine load detected by the load sensor is higher than a second predetermined value larger than the first predetermined value. It may be controlled to The controller may decrease the fuel injection amount of the second fuel injection when it is higher than the second predetermined value detected by the load sensor.
  • the present embodiment is a combustion control device for an engine that performs premixed compression ignition combustion, including a fuel injection valve that injects fuel into a combustion chamber of the engine, and a device for drawing air into the combustion chamber.
  • a fuel injection valve that injects fuel into a combustion chamber of the engine, and a device for drawing air into the combustion chamber.
  • An intake passage, an exhaust passage for discharging exhaust gas after combustion from the combustion chamber, an intake pressure sensor for detecting an intake pressure into the combustion chamber, a fuel injection amount and a fuel injection timing are determined, and the fuel injection determined
  • the fuel injection valve is operated to carry out the fuel injection according to the amount and the fuel injection timing, and when the intake pressure detected by the intake pressure sensor is lower than the predetermined pressure, the ignition timing by the fuel injection is advanced.
  • a controller configured to correct.
  • the present invention is not limited to the above embodiment.
  • the fuel injection timing of the first fuel injection and the second fuel injection is advanced, but the fuel injection of the second fuel injection is performed Only the fuel injection timing of the first fuel injection may be advanced without advancing the timing.
  • the combustion waveform in this case is a waveform shown by a solid line X in FIG.
  • the broken line Y shown in FIG. 9 shows the combustion waveform when the fuel injection timing of the second fuel injection is advanced.
  • the control mode is not limited to this. Only one of the decrease in common rail pressure and the decrease in fuel injection amount of the second fuel injection may be performed.
  • the advance amount of the fuel injection timing of the first fuel injection is not changed when the common rail pressure is reduced, but the control mode is the same. It is not limited to.
  • the fuel injection timing of the first fuel injection may be further advanced. In this case, the heat release rate waveform is closer to the heat release rate waveform obtained when the intake pressure is the reference pressure.
  • the amount of advance of the fuel injection timing of the first fuel injection may be changed to an amount according to the amount of decrease of the common rail pressure.
  • the air-fuel ratio in the combustion chamber 4 is controlled by adjusting the flow rate of the EGR gas by the EGR valve 23, but the control aspect of the air-fuel ratio is not limited to this.
  • the air-fuel ratio in the combustion chamber 4 may be controlled by changing the supercharging pressure of the turbocharger.
  • the main fuel injection is divided into the first fuel injection and the second fuel injection twice, but the aspect of the fuel injection is not limited to this.
  • the main fuel injection may be performed only once. In this case, if the engine load is lower than the low load threshold, the air-fuel ratio is made leaner than the air-fuel ratio when the intake pressure is the reference pressure, and if the engine load is higher than the low load threshold, the intake pressure The main fuel injection timing is advanced while maintaining the air-fuel ratio when the reference pressure is the reference pressure.
  • the present invention is applicable to a fuel injection device of an engine that performs premixed compression ignition combustion.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
  • Output Control And Ontrol Of Special Type Engine (AREA)

Abstract

L'invention porte sur un dispositif de commande de combustion comportant : des injecteurs de carburant (5) qui injectent du carburant dans la chambre de combustion (4) d'un moteur thermique (1) ; un capteur de pression d'admission (30) qui détecte la pression d'admission par rapport à la chambre de combustion (4) ; et une unité de commande électronique (27) qui actionne les injecteurs de carburant (5). L'unité de commande électronique (27) détermine la quantité d'injection de carburant et le calage de l'injection de carburant et elle commande les injecteurs de carburant (5) de manière à exécuter l'injection de carburant en fonction de la quantité d'injection de carburant et du calage de l'injection de carburant, et elle exécute une correction de manière à avancer le calage de l'allumage pendant l'injection de carburant lorsque la pression d'admission détectée par le capteur de pression d'admission (30) est inférieure à une pression prescrite.
PCT/JP2012/068337 2011-09-14 2012-07-19 Dispositif de commande de combustion WO2013038805A1 (fr)

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JP2011-201062 2011-09-14
JP2011201062A JP5146581B1 (ja) 2011-09-14 2011-09-14 燃焼制御装置

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Publication number Priority date Publication date Assignee Title
CA2809291C (fr) 2013-03-12 2014-11-25 Westport Power Inc. Diagnostics de systeme de carburant
JP6244160B2 (ja) * 2013-10-15 2017-12-06 株式会社豊田自動織機 燃焼制御装置
JP6975890B2 (ja) * 2018-04-09 2021-12-01 株式会社豊田自動織機 内燃機関の制御装置

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS635142A (ja) * 1986-06-26 1988-01-11 Toyota Motor Corp デイーゼルエンジンの燃料噴射時期制御方法
JP2003286879A (ja) * 2002-03-27 2003-10-10 Mazda Motor Corp ディーゼルエンジンの燃焼制御装置
JP2007120330A (ja) * 2005-10-25 2007-05-17 Toyota Industries Corp 予混合圧縮着火燃焼を行う内燃機関

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS635142A (ja) * 1986-06-26 1988-01-11 Toyota Motor Corp デイーゼルエンジンの燃料噴射時期制御方法
JP2003286879A (ja) * 2002-03-27 2003-10-10 Mazda Motor Corp ディーゼルエンジンの燃焼制御装置
JP2007120330A (ja) * 2005-10-25 2007-05-17 Toyota Industries Corp 予混合圧縮着火燃焼を行う内燃機関

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