WO2014188597A1 - Fuel injection control device of internal combustion engine - Google Patents

Fuel injection control device of internal combustion engine Download PDF

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Publication number
WO2014188597A1
WO2014188597A1 PCT/JP2013/064522 JP2013064522W WO2014188597A1 WO 2014188597 A1 WO2014188597 A1 WO 2014188597A1 JP 2013064522 W JP2013064522 W JP 2013064522W WO 2014188597 A1 WO2014188597 A1 WO 2014188597A1
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WO
WIPO (PCT)
Prior art keywords
injection control
fuel
injection
combustion state
fuel injection
Prior art date
Application number
PCT/JP2013/064522
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French (fr)
Japanese (ja)
Inventor
素成 鎗野
Original Assignee
トヨタ自動車株式会社
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Publication date
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Priority to PCT/JP2013/064522 priority Critical patent/WO2014188597A1/en
Publication of WO2014188597A1 publication Critical patent/WO2014188597A1/en

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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
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/14—Introducing closed-loop corrections
    • F02D41/1497—With detection of the mechanical response of the engine
    • F02D41/1498—With detection of the mechanical response of the engine measuring engine roughness
    • 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
    • F02B23/00—Other engines characterised by special shape or construction of combustion chambers to improve operation
    • F02B23/08—Other engines characterised by special shape or construction of combustion chambers to improve operation with positive ignition
    • F02B23/10—Other engines characterised by special shape or construction of combustion chambers to improve operation with positive ignition with separate admission of air and fuel into cylinder
    • F02B23/104—Other engines characterised by special shape or construction of combustion chambers to improve operation with positive ignition with separate admission of air and fuel into cylinder the injector being placed on a side position of the cylinder
    • 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
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M61/00—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
    • F02M61/16—Details not provided for in, or of interest apart from, the apparatus of groups F02M61/02 - F02M61/14
    • F02M61/18—Injection nozzles, e.g. having valve seats; Details of valve member seated ends, not otherwise provided for
    • F02M61/1806—Injection nozzles, e.g. having valve seats; Details of valve member seated ends, not otherwise provided for characterised by the arrangement of discharge orifices, e.g. orientation or size
    • F02M61/184—Discharge orifices having non circular sections
    • 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
    • F02D2041/389—Controlling fuel injection of the high pressure type for injecting directly into the cylinder
    • 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
    • F02D2200/06—Fuel or fuel supply system parameters
    • F02D2200/063—Lift of the valve needle
    • 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
    • F02D2200/10—Parameters related to the engine output, e.g. engine torque or engine speed
    • F02D2200/101—Engine speed
    • 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
    • F02D2200/10—Parameters related to the engine output, e.g. engine torque or engine speed
    • F02D2200/1015—Engines misfires
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D35/00—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for
    • F02D35/02—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for on interior conditions
    • F02D35/023—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for on interior conditions by determining the cylinder pressure
    • 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 fuel injection control device for an internal combustion engine.
  • Patent Document 1 describes a fuel injection valve for an internal combustion engine.
  • the fuel injection valve described in Patent Document 1 is a fuel injection valve having a slit-shaped injection hole and a variable needle lift amount.
  • JP 2001-153003 A Japanese Patent Laid-Open No. 2006-220098
  • an object of the present invention is to improve the deterioration of the combustion state when a fuel injection valve having a slit-shaped injection hole is used as a direct injection valve.
  • the present invention includes an internal combustion engine that includes a fuel injection valve that directly injects fuel into a cylinder, the fuel injection valve has a slit-shaped injection hole, and can selectively perform full lift injection control and partial lift injection control
  • the present invention relates to a fuel injection control device.
  • the apparatus of the present invention is a controller that switches the injection control to the other injection control while maintaining the total fuel injection amount before and after switching when the combustion state is worse than the predetermined combustion state during one injection control. It comprises.
  • the device of the present invention sets the total fuel injection amount after switching to the total fuel injection before switching.
  • a control unit is provided that switches the injection control from the one injection control to the other injection control while maintaining the same amount as the amount.
  • the total fuel injection amount is the total amount of fuel injected from the fuel injection valve per engine cycle.
  • the control unit increases the number of injections per engine cycle to increase the total fuel injection amount after switching (that is, partial lift injection control). Is maintained at the same amount as the total fuel injection amount before switching (that is, the total fuel injection amount in the full lift injection control).
  • the fuel flow distribution in the spray when the combustion state deteriorates, one of the causes of the deterioration is the fuel flow distribution in the spray. That is, when the combustion state deteriorates, the fuel flow rate distribution in the spray may be unfavorable for ensuring a predetermined combustion state.
  • the nozzle hole has a slit shape, the fuel flow rate distribution in the spray is changed by changing the needle lift amount. Therefore, if the injection control is switched between the full lift injection control and the partial lift injection control when the combustion state deteriorates, the distribution of the fuel flow rate in the spray is suitable for ensuring a predetermined combustion state. Is likely to be. For this reason, according to this invention, the deterioration of a combustion state can be improved.
  • the control unit changes the injection control from the full lift injection control to the partial lift while maintaining the same total fuel injection amount before and after switching. Switch to injection control.
  • the combustion state can be improved for the following reasons. That is, when the combustion state deteriorates during the full lift injection control, there is a possibility that the fuel flow rate distribution in the spray is not preferable for forming an air-fuel mixture with high homogeneity.
  • the fuel flow rate distribution in the spray changes by changing the needle lift amount. Therefore, if the injection control is switched to partial lift injection control when the combustion state deteriorates during full lift injection control, the distribution of fuel flow in the spray is suitable for forming a mixture with high homogeneity. Is likely to be. For this reason, the deterioration of the combustion state can be improved.
  • control unit maintains the same total fuel injection amount before and after switching when the combustion state is worse than the predetermined combustion state during full lift injection control at high load and low rotation.
  • the injection control is switched from full lift injection control to partial lift injection control.
  • This control has the following advantages. That is, when the combustion state deteriorates during the full lift injection control at the time of high load and low rotation, there is a high possibility that the cause of the deterioration is the fuel flow rate distribution in the spray. Therefore, if the injection control is switched to the partial lift injection control at this time, the fuel flow rate distribution in the spray is very likely to be a distribution suitable for forming an air-fuel mixture with high homogeneity. For this reason, according to this invention, deterioration of a combustion state can be improved more reliably.
  • the control unit switches the injection control from the partial lift injection control to the full lift injection control when the combustion state is the predetermined combustion state during the partial lift injection control, the combustion state is changed to the predetermined combustion state. If maintained, the injection control may be switched from partial lift injection control to full lift injection control while maintaining the same total fuel injection amount before and after switching.
  • This control has the following advantages. That is, deposits may accumulate in the nozzle holes. And when a nozzle hole is slit shape, many deposits accumulate on the edge part wall surface of the width direction of a nozzle hole. On the other hand, according to full lift injection, the flow rate of fuel flowing in the vicinity of the end wall surface in the width direction of the nozzle hole is larger than in partial lift injection. According to the present invention, as long as the combustion state is maintained at a predetermined combustion state, full lift injection control is performed. Therefore, deposits accumulated in the nozzle holes can be removed while maintaining the combustion state at a predetermined combustion state. In addition, it is possible to suppress deposit accumulation in the nozzle hole.
  • the control unit performs the partial lift injection control while maintaining the total fuel injection amount before and after switching to the same amount. To full lift injection control.
  • the combustion state can be improved for the following reasons. That is, when the combustion state deteriorates during the partial lift injection control, one of the causes of the deterioration is the fuel flow rate distribution in the spray. That is, there is a possibility that the fuel flow rate distribution in the spray is not preferable for maintaining a predetermined combustion state.
  • the flow rate distribution in the spray changes by changing the needle lift amount. Therefore, if the injection control is switched to the full lift injection control when the combustion state deteriorates during the partial lift injection control, the fuel flow distribution in the spray becomes a distribution suitable for maintaining a predetermined combustion state. Probability is high. For this reason, according to this invention, the deterioration of a combustion state can be improved.
  • FIG. 1 shows an internal combustion engine to which a fuel injection control device of an embodiment of the present invention is applied.
  • FIG. 2 shows the fuel injection valve of the first embodiment.
  • FIG. 3A shows a change in the needle lift amount during the full lift injection
  • FIG. 3B shows a change in the needle lift amount during the partial lift injection.
  • FIG. 4 shows the nozzle hole and its periphery of the fuel injection valve of the first embodiment.
  • FIG. 5A shows fuel spray during full lift injection
  • FIG. 5B shows fuel spray during partial lift injection.
  • 6A is a diagram for explaining the spray angle at the time of full lift injection
  • FIG. 6B is a diagram for explaining the spray angle at the time of partial lift injection.
  • FIG. 7 shows an example of the fuel injection control flow of the first embodiment.
  • FIG. 8 shows a part of another example of the fuel injection control flow of the first embodiment.
  • FIG. 9 shows a part of another example of the fuel injection control flow of the first embodiment.
  • FIG. 10 shows an example of the fuel
  • FIG. 1 An internal combustion engine to which the fuel injection control device of the present invention is applied is shown in FIG.
  • 10 is a body of an internal combustion engine (hereinafter referred to as “engine body”)
  • 11 is a fuel injection valve
  • 12 is a cylinder head
  • 13 is a cylinder block
  • 14 is an intake valve
  • 15 is an exhaust valve
  • 16 is a spark plug
  • 17 Is an in-cylinder pressure sensor
  • 18 is a combustion chamber
  • 19 is a piston
  • 90 is an electronic control unit (ECU).
  • ECU electronice control unit
  • the fuel injection valve 11 is attached to a part of the engine body 10 (for example, a part of the cylinder head 12 or a part of the cylinder block 13) on the side of the intake valve 13 in the upper part of the cylinder (that is, the combustion chamber 18). .
  • FIG. 2 shows the configuration of the fuel injection valve 11.
  • 30 is a nozzle
  • 31 is a needle valve
  • 32 is a fuel injection hole (hereinafter “injection hole”)
  • 33 is a fuel passage
  • 34 is a solenoid
  • 35 is a spring
  • 36 is a fuel intake port
  • 37 is an injection valve.
  • Each axis is shown.
  • the injection valve axis 37 is an axis extending in the longitudinal direction of the fuel injection valve 11.
  • the fuel injection valve 11 is a so-called inner opening type fuel injection valve.
  • the fuel injection valve 11 can selectively perform either full lift injection or partial lift injection. As shown in FIG.
  • the full lift injection is a fuel injection that raises the needle valve 31 to the maximum lift amount (that is, the maximum lift injection), and the partial lift injection is the one shown in FIG. ),
  • the fuel injection that is, partial lift injection
  • the needle lift amount can be controlled by controlling the energization time to the fuel injection valve 11.
  • FIG. 3A shows the transition of the needle lift amount of one full lift injection
  • FIG. 3B shows the transition of the needle lift amount of three partial lift injections. ing.
  • FIG. 4 shows the structure of the injection hole 32 and its periphery of the fuel injection valve 11 of the first embodiment.
  • FIG. 4A shows the tip of the fuel injection valve 11 when the tip of the fuel injection valve 11 is viewed from the outside of the fuel injection valve 11 along the injection valve axis 37.
  • 4B shows a cross section taken along line BB in FIG. 4A
  • FIG. 4C shows a cross section taken along line CC in FIG. 4A.
  • 30 is a nozzle
  • 31 is a needle valve
  • 32 is an injection hole
  • 37 is an injection valve axis
  • 38 is a sack
  • 39 is a needle seat portion (hereinafter “sheet portion”)
  • 40 is a nozzle seat wall surface
  • 41 is a needle.
  • the sheet wall surface, 42 is the nozzle hole central region
  • 43 is the nozzle hole end region
  • 44 is the inlet
  • 45 is the outlet
  • 46 is the sack center
  • 47 is the nozzle central axis
  • 48 is the nozzle end axis.
  • the sack center 46 is the center of the space constituting the sack 38 and is a point on the injection valve axis 37.
  • the nozzle seat wall surface 40 is a wall surface on which the needle seat wall surface 41 is seated when the fuel injection valve 11 is fully closed (that is, when the needle lift amount becomes zero).
  • the nozzle hole central axis 47 is an axis that penetrates the center of the nozzle hole 32 in the fuel flow direction (that is, the direction in which fuel flows in the nozzle hole).
  • the nozzle hole end axis 48 is an axis that penetrates the end of the nozzle hole 13 in the fuel flow direction.
  • the nozzle hole 32 has an inlet 44 and an outlet 45.
  • the inlet 44 is open to the sack 38, and the fuel flows into the injection hole 32 through the inlet 44.
  • the outlet 45 is open to the outside of the fuel injection valve 11, and the fuel is injected from the outlet 45.
  • the inner region of the nozzle hole 32 is divided into a nozzle hole central region 42 and a nozzle hole end region 43.
  • the nozzle hole central region 42 is a region extending from the inlet 44 to the outlet 45 along the nozzle central axis 47.
  • the nozzle hole end region 43 is a region that extends from the inlet 44 to the outlet 45 along each nozzle hole end axis 48 on both sides of the nozzle hole central region 42.
  • the injection hole 32 when the injection hole 32 is viewed in its cross section, the injection hole 32 has a rectangular cross section.
  • the cross section of the injection hole is a cross section when the injection hole is cut along a plane perpendicular to the injection hole central axis 47.
  • FIG. 4B when the nozzle hole 32 is viewed in cross section BB, the nozzle hole 32 has a fan-shaped shape that spreads from the inlet 44 toward the outlet 45. Therefore, the flow path cross section of the nozzle hole 32 gradually increases from the inlet 44 toward the outlet 45.
  • the channel area of the outlet 45 is larger than the channel area of the inlet 44.
  • the cross section BB is a cross section when the nozzle hole is cut along one plane including the nozzle hole central axis 47 and each nozzle hole end axis 48.
  • the nozzle hole 32 when the nozzle hole 32 is viewed in its longitudinal section, the nozzle hole 32 has a substantially rectangular shape.
  • the vertical cross section of the injection hole is a cross section when cut along one plane including the injection hole central axis 47 and the injection valve axis 37.
  • the nozzle hole 32 is formed so that the nozzle hole center axis 47 and the nozzle hole end axis 48 intersect the sack center 46. It is formed at the tip.
  • the injection hole 32 is formed at the tip of the nozzle 30 so that the injection hole central axis 47 has a certain angle with respect to the injection valve axis 37.
  • the injection hole may be formed at the tip of the nozzle 30 such that the injection hole central axis 47 coincides with the injection valve axis 37.
  • FIG. 5 shows fuel spray injected from the fuel injection valve 11 of the first embodiment (hereinafter referred to as “spray”).
  • FIG. 5 shows spraying when the tip of the fuel injection valve 11 is viewed from the outside of the fuel injection valve 11 along the injection valve axis 37.
  • FIG. 5A shows spray during full lift injection
  • FIG. 5B shows spray during partial lift injection.
  • 50 is spray sprayed from the nozzle hole center region 42 through the outlet 45 (hereinafter “spray center part”), and 51 is sprayed from the nozzle hole end region 43 through the outlet 45.
  • Spray hereinafter “spray end”.
  • the fuel flow rate (see FIG. 5A) of the spray central portion 50 at the time of full lift injection is the spray central portion at the time of partial lift injection.
  • Less than 50 fuel flow rates see FIG. 5B). That is, the ratio of the injection amount from the nozzle hole central region to the total injection amount at the time of full lift injection is smaller than the ratio of the injection amount from the nozzle hole central region to the total injection amount at the time of partial lift injection.
  • the fuel flow rate at the nozzle hole end 51 during full lift injection is larger than the fuel flow rate at the spray end 51 during partial lift injection (see FIG. 5B). That is, the ratio of the injection amount from the nozzle hole end region to the total injection amount at the time of full lift injection is larger than the ratio of the injection amount from the nozzle hole end region to the total injection amount at the time of partial lift injection.
  • the spray angle 52 during full lift injection is the same as the spray angle 52 during partial lift injection (see FIG. Larger than B).
  • the penetration force at the time of full lift injection is larger than the penetration force at the time of partial lift injection.
  • the spray angle 52 is the angle between the outer edges 53 of the spray, and the penetration force is the force that the spray travels in the cylinder.
  • the fuel injection control of the first embodiment will be described.
  • the fuel flow rate at the center of the spray at the time of full lift injection is the fuel flow rate at the center of the spray at the time of partial lift injection (see FIG. More than B).
  • the fuel flow rate at the spray end during full lift injection is smaller than the fuel flow rate at the spray end during partial lift injection (see FIG. 5B).
  • the injection control in view of the relationship between the needle lift amount and the fuel flow distribution in the spray, when the combustion state becomes worse than the predetermined combustion state during the full lift injection control, the injection control is changed from the full lift injection control. It is switched to partial lift injection control.
  • the full lift injection control is a control for executing full lift injection at a predetermined timing (specifically, a timing near the compression top dead center), and the partial lift injection control is a predetermined timing (specifically, In this case, the partial lift injection is executed at a timing near the compression top dead center.
  • the total fuel injection amount before and after the switching is maintained at the same amount. That is, the total fuel injection amount after switching (that is, the total fuel injection amount during partial lift injection control) is maintained at the same amount as the total fuel injection amount before the switching (that is, total fuel injection amount during full lift injection control). It is preferable.
  • the total fuel injection amount is the total amount of fuel injected by the fuel injection valve per engine cycle.
  • a means for maintaining the same total fuel injection amount before and after switching for example, a means for increasing the number of injections per engine cycle in the partial lift injection control can be employed.
  • the atomization degree of the fuel at the spray end is poor, and therefore, the fuel at the spray end is difficult to burn (that is, the combustion of the fuel at the spray end is difficult to proceed, that is, The combustion speed of the fuel at the spray end is slow), and as a whole, there is a possibility that an air-fuel mixture with high homogeneity is not formed in the cylinder. That is, there is a possibility that the fuel flow rate distribution in the spray is unfavorable for forming a mixture with high homogeneity.
  • the fuel flow rate distribution in the spray changes by changing the needle lift amount. Specifically, the fuel flow rate at the spray end is reduced by switching the injection control from full lift injection control to partial lift injection control. Accordingly, if the injection control is switched to the partial lift injection control when the combustion state deteriorates during the full lift injection control, there is a high possibility that the degree of atomization of the fuel at the spray end is improved. That is, there is a high possibility that the fuel flow rate distribution in the spray becomes a distribution suitable for forming an air-fuel mixture with high homogeneity. For this reason, according to 1st Embodiment, the deterioration of a combustion state can be improved.
  • the partial lift injection control may be continued regardless of whether or not the combustion state is worse than the predetermined combustion state during the partial lift injection control.
  • the combustion state becomes worse than the predetermined combustion state during the partial lift injection control, it is preferable to switch the injection control from the partial lift injection control to the full lift injection control. According to this, the following advantages can be obtained.
  • the fuel flow rate distribution in the spray changes by changing the needle lift amount. Specifically, the fuel flow rate at the spray end is increased by switching the injection control from the partial lift injection control to the full lift injection control. Therefore, if the injection control is switched to the full lift injection control when the combustion state deteriorates during the partial lift injection control, it is highly possible that the combustion speed of the fuel at the spray end portion is improved. For this reason, when the combustion state becomes worse than the predetermined combustion state during the partial lift injection control, the deterioration of the combustion state can be improved by switching the injection control from the partial lift injection control to the full lift injection control. Benefits are gained.
  • the total fuel injection amount before and after the switching is maintained at the same amount. That is, the total fuel injection amount after switching (that is, the total fuel injection amount during full lift injection control) is maintained at the same amount as the total fuel injection amount before the switching (that is, total fuel injection amount during partial lift injection control). It is preferable.
  • Deposits may accumulate in the nozzle hole. And, like the fuel injection valve of the first embodiment, when the injection hole has a slit shape, many deposits are formed on the wall surface of the end region of the injection hole (in other words, the end of the injection hole in the width direction). Deposited on the wall). On the other hand, according to full lift injection, the flow rate of fuel flowing through the end region of the injection hole (in other words, in the vicinity of the end wall surface in the width direction of the injection hole) is larger than in partial lift injection.
  • the injection control Is switched from partial lift injection control to full lift injection control (that is, by performing full lift injection control as long as the combustion state is maintained at a predetermined combustion state), deposits accumulated in the nozzle holes can be removed. In addition, it is possible to obtain an advantage that deposit accumulation in the nozzle hole can be suppressed.
  • the deposit is a substance generated by in-cylinder combustion, for example, an unburned material such as fuel or lubricating oil.
  • the combustion state can be grasped by, for example, the torque fluctuation amount, the in-cylinder pressure fluctuation amount, the engine speed fluctuation amount, the exhaust temperature, and the exhaust properties (for example, the unburned HC amount).
  • the torque fluctuation amount is larger than a predetermined amount, or when the in-cylinder pressure fluctuation amount is larger than a predetermined amount, or when the engine rotational speed fluctuation amount is larger than a predetermined amount, or the exhaust
  • the temperature is lower than the predetermined temperature, or when the exhaust property is worse than the predetermined property (for example, when the unburned HC amount is larger than the predetermined amount)
  • the combustion state is worse than the predetermined combustion state.
  • the torque fluctuation amount is the fluctuation amount of the engine output torque
  • the fluctuation amount of the in-cylinder pressure is the fluctuation amount of the in-cylinder pressure (or the maximum value of the in-cylinder pressure) at the specific crank angle.
  • the combustion state can be grasped by misfire, for example. That is, when the internal combustion engine has means for detecting misfire in the cylinder (for example, misfire sensor), when misfire occurs, or when the number of misfires within a predetermined time is greater than the predetermined number It can be determined that the combustion state is worse than the predetermined combustion state.
  • misfire for example. That is, when the internal combustion engine has means for detecting misfire in the cylinder (for example, misfire sensor), when misfire occurs, or when the number of misfires within a predetermined time is greater than the predetermined number It can be determined that the combustion state is worse than the predetermined combustion state.
  • FIG. 1 An example of the fuel injection control flow of the first embodiment is shown in FIG. This flow is executed every time a predetermined time elapses.
  • the target fuel injection amount Q is determined.
  • CT> CTth a predetermined amount
  • step 13 the partial lift amount (that is, the needle lift amount in one partial lift injection). ) Lp is determined.
  • the number of injections Np is determined based on the target fuel injection amount Q determined at step 10 and the partial lift amount Lp determined at step 13. That is, the number of partial lift injections required to inject the fuel of the target fuel injection amount Q determined in step 10 is determined by the partial lift injection of the partial lift amount Lp determined in step 13.
  • the injection control is switched from full lift injection control to partial lift injection control, and the flow ends. In this case, after the injection control is switched in step 15, the partial lift injection at the partial lift amount Lp determined in step 13 is executed for the number of injections Np determined in step 14 in each engine cycle of each cylinder. Is done.
  • FIGS. 1 and 2 of First Embodiment Another example of the fuel injection control flow of the first embodiment is shown in FIGS. This flow is executed every time a predetermined time elapses. Since steps 11 to 16 of this flow are the same as steps 11 to 16 of the flow of FIG. 7, description of these steps is omitted.
  • step 22 it is determined whether or not the torque fluctuation amount CT is larger than a predetermined amount CTth (CT> CTth).
  • CT> CTth a predetermined amount
  • the injection control is switched to the full lift injection control in step 21, the full lift injection control is continued.
  • the partial lift amount Lp is determined in step 23.
  • the number of injections Np is determined based on the target fuel injection amount Q determined at step 10 and the partial lift amount Lp determined at step 23.
  • the number of partial lift injections required to inject the fuel of the target fuel injection amount Q determined in step 10 is determined by the partial lift injection of the partial lift amount Lp determined in step 23.
  • the injection control is switched from full lift injection control to partial lift injection control, and the flow ends.
  • the partial lift injection at the partial lift amount Lp determined in step 23 is executed for the number of injections Np determined in step 24 in each engine cycle of each cylinder. Is done.
  • step 20 to step 25 of this flow when the torque fluctuation amount is equal to or less than the predetermined amount during the partial lift injection control, the injection control is once switched to the full lift injection control, and the subsequent torque fluctuation amount is equal to or less than the predetermined amount. Then, the full lift injection control is continued as it is, while if the torque fluctuation amount is larger than the predetermined amount, the injection control is returned to the partial lift injection control.
  • Second Embodiment A second embodiment will be described.
  • the configuration and control of the second embodiment not described below are the same as the configuration and control of the first embodiment, respectively, or when considering the configuration or control of the second embodiment described below.
  • the configuration and control are naturally derived from the configuration or control of the embodiment.
  • the injection control is switched from the full lift injection control to the partial lift injection control when the combustion state is worse than the predetermined combustion state during full lift injection control at the time of high load and low rotation.
  • the total fuel injection amount before and after switching is maintained at the same amount. That is, the total fuel injection amount after switching (that is, the total fuel injection amount during partial lift injection control) is maintained at the same amount as the total fuel injection amount before the switching (that is, total fuel injection amount during full lift injection control). It is preferable.
  • FIG. 3 An example of the fuel injection control flow of the second embodiment is shown in FIG. This flow is executed every time a predetermined time elapses.
  • the target fuel injection amount Q is determined.
  • CT> CTth a predetermined amount
  • step 33 the engine speed NE is smaller than the predetermined engine speed NEth and the engine load KL. Is greater than a predetermined load KLth (NE ⁇ NEth and KL> KLth).
  • the partial lift amount Lp is determined in step 34.
  • the number of injections Np is determined based on the target fuel injection amount Q determined at step 30 and the partial lift amount Lp determined at step 34. That is, the number of partial lift injections required to inject the fuel of the target fuel injection amount Q determined in step 30 is determined by the partial lift injection of the partial lift amount Lp determined in step 34.
  • the injection control is switched from full lift injection control to partial lift injection control, and the flow ends. In this case, after the injection control is switched in step 36, the partial lift injection at the partial lift amount Lp determined in step 34 is executed for the number of injections Np determined in step 35 in each engine cycle of each cylinder. Is done.
  • step 33 When it is determined in step 33 that NE ⁇ NEth and KL> KLth are not satisfied, the flow ends as it is. In this case, the current injection control (that is, full lift injection control) is continued.
  • step 37 the injection control is switched from partial lift injection control to full lift injection control, and the flow finish.
  • the full lift injection control is executed so that the fuel of the target fuel injection amount Q determined in step 30 is injected in each engine cycle of each cylinder.
  • the flow described above performs both switching from full lift injection control to partial injection control and switching from partial lift injection control to full lift injection control in accordance with the combustion state.
  • the present invention is also applicable to the case where only one of these switching is performed according to the combustion state.
  • the present invention has been described by taking as an example the case where the fuel injection valve is attached to the part of the engine body on the side of the intake valve at the upper part of the cylinder.
  • the present invention can be applied to any part of the engine body as long as it directly injects fuel.
  • the embodiment of the present invention when viewed broadly, includes the fuel injection valve 11 that directly injects fuel into the cylinder, the fuel injection valve has the slit-shaped injection hole 32, and provides full lift control and partial lift.
  • the present invention relates to a fuel injection control device for an internal combustion engine capable of selectively performing control.
  • the combustion state is worse than the predetermined combustion state during one injection control (for example, when the torque fluctuation amount is larger than the predetermined amount)
  • the total fuel injection amount before and after switching is set to the same amount. It can be said that the control part (electronic control apparatus) 90 which switches injection control to the other injection control is maintained.
  • control unit maintains the same total fuel injection amount before and after switching when the combustion state is worse than a predetermined combustion state during the full lift injection control.
  • the injection control is switched from full lift injection control to partial lift injection control.
  • control unit performs before and after switching when the combustion state is worse than the predetermined combustion state during full lift injection control during high load and low rotation.
  • the injection control that maintains the same total fuel injection amount may be switched from full lift injection control to partial lift injection control.
  • control unit changes the injection control from the partial lift injection control to the full lift injection control when the fuel state is the predetermined combustion state during the partial lift injection control. If the combustion state is maintained at the predetermined combustion state even after switching, the injection control may be switched from partial lift injection control to full lift injection control while maintaining the same total fuel injection amount before and after switching. .
  • control unit determines the total fuel injection amount before and after switching when the combustion state is worse than the predetermined combustion state during the partial lift injection control. While maintaining the same amount, the injection control is switched from the partial lift injection control to the full lift injection control.

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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)

Abstract

The objective of the present invention is to ameliorate a deterioration in combustion state in the case of using a fuel injection valve provided with a slit-shaped injection opening as a fuel injection valve that directly injects fuel into a cylinder. The fuel injection control device of an internal combustion engine is provided with a fuel injection valve (11) that directly injects fuel into a cylinder, the fuel injection valve has a slit-shaped injection opening (32), and the fuel injection control device can selectively execute full lift injection control and partial lift injection control. The device is equipped with a control unit (90) that, when the combustion state during full lift injection control has deteriorated beyond a predetermined combustion state, switches the injection control from the full lift injection control to the partial lift injection control while maintaining the total amount of fuel injection before and after switching at the same amount.

Description

内燃機関の燃料噴射制御装置Fuel injection control device for internal combustion engine
　本発明は、内燃機関の燃料噴射制御装置に関する。 The present invention relates to a fuel injection control device for an internal combustion engine.
　特許文献１に内燃機関の燃料噴射弁が記載されている。特許文献１に記載の燃料噴射弁は、スリット形状の噴孔を備え、ニードルリフト量が可変な燃料噴射弁である。 Patent Document 1 describes a fuel injection valve for an internal combustion engine. The fuel injection valve described in Patent Document 1 is a fuel injection valve having a slit-shaped injection hole and a variable needle lift amount.
特開２００１－１５３００３号公報JP 2001-153003 A 特開２００６－２２００９８号公報Japanese Patent Laid-Open No. 2006-220098
　ところで、直噴タイプの内燃機関では、均質な混合気が形成されづらい場合がある。混合気の均質度が低いと、燃焼サイクル毎に混合気の均質度が異なり、機関運転中の燃焼状態が悪化することがある。ところが、本願の発明者の研究により、スリット形状の噴孔を備えた燃料噴射弁を直噴噴射弁（すなわち、筒内に燃料を直接噴射する燃料噴射弁）として利用した場合、燃焼状態に応じて燃料噴射形態を変更することによって燃焼状態の悪化を改善できることが判明した。 By the way, in a direct injection type internal combustion engine, it may be difficult to form a homogeneous air-fuel mixture. When the homogeneity of the air-fuel mixture is low, the homogeneity of the air-fuel mixture differs for each combustion cycle, and the combustion state during engine operation may deteriorate. However, according to the research by the inventors of the present application, when a fuel injection valve having a slit-shaped injection hole is used as a direct injection valve (that is, a fuel injection valve that directly injects fuel into a cylinder), it depends on the combustion state. It has been found that the deterioration of the combustion state can be improved by changing the fuel injection mode.
　そこで、本発明の目的は、スリット形状の噴孔を備えた燃料噴射弁を直噴噴射弁として利用する場合において、燃焼状態の悪化を改善することにある。 Therefore, an object of the present invention is to improve the deterioration of the combustion state when a fuel injection valve having a slit-shaped injection hole is used as a direct injection valve.
　本発明は、筒内に燃料を直接噴射する燃料噴射弁を備え、該燃料噴射弁がスリット形状の噴孔を有し、フルリフト噴射制御とパーシャルリフト噴射制御とを選択的に実施可能な内燃機関の燃料噴射制御装置に関する。本発明の装置は、一方の噴射制御中に燃焼状態が所定の燃焼状態よりも悪化した場合、切替前後の総燃料噴射量を同量に維持しつつ噴射制御を他方の噴射制御に切り替える制御部を具備する。 The present invention includes an internal combustion engine that includes a fuel injection valve that directly injects fuel into a cylinder, the fuel injection valve has a slit-shaped injection hole, and can selectively perform full lift injection control and partial lift injection control The present invention relates to a fuel injection control device. The apparatus of the present invention is a controller that switches the injection control to the other injection control while maintaining the total fuel injection amount before and after switching when the combustion state is worse than the predetermined combustion state during one injection control. It comprises.
　すなわち、本発明の装置は、前記２つの噴射制御のうち一方の噴射制御の実施中に燃焼状態が所定の燃焼状態よりも悪化した場合、切替後の総燃料噴射量を切替前の総燃料噴射量と同量に維持しつつ噴射制御を前記一方の噴射制御から他方の噴射制御に切り替える制御部を具備する。ここで、前記総燃料噴射量は、１機関サイクル当たりに前記燃料噴射弁から噴射される燃料の総量である。また、前記制御部は、前記他方の噴射制御が前記パーシャルリフト噴射制御である場合、たとえば、１機関サイクル当たりの噴射回数を増やすことによって切替後の総燃料噴射量（すなわち、パーシャルリフト噴射制御での総燃料噴射量）を切替前の総燃料噴射量（すなわち、フルリフト噴射制御での総燃料噴射量）と同量に維持する。 That is, when the combustion state deteriorates from the predetermined combustion state during the execution of one of the two injection controls, the device of the present invention sets the total fuel injection amount after switching to the total fuel injection before switching. A control unit is provided that switches the injection control from the one injection control to the other injection control while maintaining the same amount as the amount. Here, the total fuel injection amount is the total amount of fuel injected from the fuel injection valve per engine cycle. Further, when the other injection control is the partial lift injection control, the control unit, for example, increases the number of injections per engine cycle to increase the total fuel injection amount after switching (that is, partial lift injection control). Is maintained at the same amount as the total fuel injection amount before switching (that is, the total fuel injection amount in the full lift injection control).
　直噴タイプの内燃機関において、燃焼状態が悪化した場合、その悪化の原因の１つとして、噴霧内の燃料流量分布が挙げられる。すなわち、燃焼状態が悪化した場合、噴霧内の燃料流量分布が所定の燃焼状態を確保するには好ましくない分布になっている可能性がある。一方、噴孔がスリット形状である場合、ニードルリフト量の変更によって噴霧内の燃料流量分布が変わる。したがって、燃焼状態が悪化した場合にフルリフト噴射制御とパーシャルリフト噴射制御との間で噴射制御が切り替えられれば、少なからず、噴霧内の燃料流量分布が所定の燃焼状態を確保するのに適した分布になる可能性が高い。このため、本発明によれば、燃焼状態の悪化を改善することができる。 In a direct injection type internal combustion engine, when the combustion state deteriorates, one of the causes of the deterioration is the fuel flow distribution in the spray. That is, when the combustion state deteriorates, the fuel flow rate distribution in the spray may be unfavorable for ensuring a predetermined combustion state. On the other hand, when the nozzle hole has a slit shape, the fuel flow rate distribution in the spray is changed by changing the needle lift amount. Therefore, if the injection control is switched between the full lift injection control and the partial lift injection control when the combustion state deteriorates, the distribution of the fuel flow rate in the spray is suitable for ensuring a predetermined combustion state. Is likely to be. For this reason, according to this invention, the deterioration of a combustion state can be improved.
　なお、前記制御部は、たとえば、フルリフト噴射制御中に燃焼状態が所定の燃焼状態よりも悪化した場合、切替前後の総燃料噴射量を同量に維持しつつ噴射制御をフルリフト噴射制御からパーシャルリフト噴射制御に切り替える。 For example, when the combustion state becomes worse than a predetermined combustion state during the full lift injection control, the control unit changes the injection control from the full lift injection control to the partial lift while maintaining the same total fuel injection amount before and after switching. Switch to injection control.
　これによれば、以下の理由から、燃焼状態を改善することができる。すなわち、フルリフト噴射制御中に燃焼状態が悪化した場合、噴霧内の燃料流量分布が均質度の高い混合気を形成するには好ましくない分布になっている可能性がある。一方、上述したように、噴孔がスリット形状である場合、ニードルリフト量の変更によって噴霧内の燃料流量分布が変わる。したがって、フルリフト噴射制御中に燃焼状態が悪化した場合に噴射制御がパーシャルリフト噴射制御に切り替えられれば、少なからず、噴霧内の燃料流量分布が均質度の高い混合気を形成するのに適した分布になる可能性が高い。このため、燃焼状態の悪化を改善することができる。 According to this, the combustion state can be improved for the following reasons. That is, when the combustion state deteriorates during the full lift injection control, there is a possibility that the fuel flow rate distribution in the spray is not preferable for forming an air-fuel mixture with high homogeneity. On the other hand, as described above, when the nozzle hole has a slit shape, the fuel flow rate distribution in the spray changes by changing the needle lift amount. Therefore, if the injection control is switched to partial lift injection control when the combustion state deteriorates during full lift injection control, the distribution of fuel flow in the spray is suitable for forming a mixture with high homogeneity. Is likely to be. For this reason, the deterioration of the combustion state can be improved.
　また、前記制御部は、たとえば、高負荷低回転時であってフルリフト噴射制御中に燃焼状態が前記所定の燃焼状態よりも悪化した場合に切替前後の総燃料噴射量を同量に維持しつつ噴射制御をフルリフト噴射制御からパーシャルリフト噴射制御に切り替える。 In addition, for example, the control unit maintains the same total fuel injection amount before and after switching when the combustion state is worse than the predetermined combustion state during full lift injection control at high load and low rotation. The injection control is switched from full lift injection control to partial lift injection control.
　この制御には、以下の利点がある。すなわち、高負荷低回転時のフルリフト噴射制御中に燃焼状態が悪化した場合、その悪化の原因が噴霧内の燃料流量分布である可能性が高い。したがって、このときに噴射制御がパーシャルリフト噴射制御に切り替えられれば、噴霧内の燃料流量分布が均質度の高い混合気を形成するのに適した分布になる可能性が非常に高い。このため、本発明によれば、燃焼状態の悪化をより確実に改善することができる。 This control has the following advantages. That is, when the combustion state deteriorates during the full lift injection control at the time of high load and low rotation, there is a high possibility that the cause of the deterioration is the fuel flow rate distribution in the spray. Therefore, if the injection control is switched to the partial lift injection control at this time, the fuel flow rate distribution in the spray is very likely to be a distribution suitable for forming an air-fuel mixture with high homogeneity. For this reason, according to this invention, deterioration of a combustion state can be improved more reliably.
　また、前記制御部は、パーシャルリフト噴射制御中に燃焼状態が前記所定の燃焼状態であるときに噴射制御をパーシャルリフト噴射制御からフルリフト噴射制御に切り替えたとしても燃焼状態が前記所定の燃焼状態に維持される場合、切替前後の総燃料噴射量を同量に維持しつつ噴射制御をパーシャルリフト噴射制御からフルリフト噴射制御に切り替えるようにしてもよい。 In addition, even when the control unit switches the injection control from the partial lift injection control to the full lift injection control when the combustion state is the predetermined combustion state during the partial lift injection control, the combustion state is changed to the predetermined combustion state. If maintained, the injection control may be switched from partial lift injection control to full lift injection control while maintaining the same total fuel injection amount before and after switching.
　この制御には、以下の利点がある。すなわち、噴孔にデポジットが堆積することがある。そして、噴孔がスリット形状である場合、多くのデポジットは、噴孔の幅方向の端部壁面に堆積する。一方、フルリフト噴射によれば、パーシャルリフト噴射に比べて、噴孔の幅方向の端部壁面近傍を流れる燃料流量が多い。本発明によれば、燃焼状態が所定の燃焼状態に維持される限り、フルリフト噴射制御が行われるので、燃焼状態を所定の燃焼状態に維持しつつ、噴孔に堆積したデポジットを除去することができるとともに、噴孔へのデポジットの堆積を抑制することができる。 This control has the following advantages. That is, deposits may accumulate in the nozzle holes. And when a nozzle hole is slit shape, many deposits accumulate on the edge part wall surface of the width direction of a nozzle hole. On the other hand, according to full lift injection, the flow rate of fuel flowing in the vicinity of the end wall surface in the width direction of the nozzle hole is larger than in partial lift injection. According to the present invention, as long as the combustion state is maintained at a predetermined combustion state, full lift injection control is performed. Therefore, deposits accumulated in the nozzle holes can be removed while maintaining the combustion state at a predetermined combustion state. In addition, it is possible to suppress deposit accumulation in the nozzle hole.
　また、前記制御部は、たとえば、パーシャルリフト噴射制御中に燃焼状態が前記所定の燃焼状態よりも悪化した場合、切替前後の総燃料噴射量を同量に維持しつつ噴射制御をパーシャルリフト噴射制御からフルリフト噴射制御に切り替える。 For example, when the combustion state is worse than the predetermined combustion state during the partial lift injection control, the control unit performs the partial lift injection control while maintaining the total fuel injection amount before and after switching to the same amount. To full lift injection control.
　これによれば、以下の理由から、燃焼状態を改善することができる。すなわち、パーシャルリフト噴射制御中に燃焼状態が悪化した場合、その悪化の原因の１つとして、噴霧内の燃料流量分布が挙げられる。すなわち、噴霧内の燃料流量分布が所定の燃焼状態を維持するには好ましくない分布になっている可能性がある。一方、上述したように、噴孔がスリット形状である場合、ニードルリフト量の変更によって噴霧内の流量分布が変わる。したがって、パーシャルリフト噴射制御中に燃焼状態が悪化した場合に噴射制御がフルリフト噴射制御に切り替えられれば、少なからず、噴霧内の燃料流量分布が所定の燃焼状態を維持するのに適した分布になる可能性が高い。このため、本発明によれば、燃焼状態の悪化を改善することができる。 According to this, the combustion state can be improved for the following reasons. That is, when the combustion state deteriorates during the partial lift injection control, one of the causes of the deterioration is the fuel flow rate distribution in the spray. That is, there is a possibility that the fuel flow rate distribution in the spray is not preferable for maintaining a predetermined combustion state. On the other hand, as described above, when the nozzle hole has a slit shape, the flow rate distribution in the spray changes by changing the needle lift amount. Therefore, if the injection control is switched to the full lift injection control when the combustion state deteriorates during the partial lift injection control, the fuel flow distribution in the spray becomes a distribution suitable for maintaining a predetermined combustion state. Probability is high. For this reason, according to this invention, the deterioration of a combustion state can be improved.
図１は本発明の実施形態の燃料噴射制御装置が適用される内燃機関を示している。FIG. 1 shows an internal combustion engine to which a fuel injection control device of an embodiment of the present invention is applied. 図２は第１実施形態の燃料噴射弁を示している。FIG. 2 shows the fuel injection valve of the first embodiment. 図３（Ａ）はフルリフト噴射時のニードルリフト量の変化を示し、図３（Ｂ）はパーシャルリフト噴射時のニードルリフト量の変化を示している。FIG. 3A shows a change in the needle lift amount during the full lift injection, and FIG. 3B shows a change in the needle lift amount during the partial lift injection. 図４は第１実施形態の燃料噴射弁の噴孔およびその周辺を示している。FIG. 4 shows the nozzle hole and its periphery of the fuel injection valve of the first embodiment. 図５（Ａ）はフルリフト噴射時の燃料噴霧を示し、図５（Ｂ）はパーシャルリフト噴射時の燃料噴霧を示している。FIG. 5A shows fuel spray during full lift injection, and FIG. 5B shows fuel spray during partial lift injection. 図６（Ａ）はフルリフト噴射時の噴霧角度を説明するための図であり、図６（Ｂ）はパーシャルリフト噴射時の噴霧角度を説明するための図である。6A is a diagram for explaining the spray angle at the time of full lift injection, and FIG. 6B is a diagram for explaining the spray angle at the time of partial lift injection. 図７は第１実施形態の燃料噴射制御フローの一例を示している。FIG. 7 shows an example of the fuel injection control flow of the first embodiment. 図８は第１実施形態の燃料噴射制御フローの別の一例の一部を示している。FIG. 8 shows a part of another example of the fuel injection control flow of the first embodiment. 図９は第１実施形態の燃料噴射制御フローの別の一例の一部を示している。FIG. 9 shows a part of another example of the fuel injection control flow of the first embodiment. 図１０は第２実施形態の燃料噴射制御フローの一例を示している。FIG. 10 shows an example of the fuel injection control flow of the second embodiment.
＜第１実施形態＞
　以下、図面を参照して本発明の実施形態について説明する。本発明の燃料噴射制御装置が適用される内燃機関が図１に示されている。図１において、１０は内燃機関の本体（以下「機関本体」）、１１は燃料噴射弁、１２はシリンダヘッド、１３はシリンダブロック、１４は吸気弁、１５は排気弁、１６は点火プラグ、１７は筒内圧センサ、１８は燃焼室、１９はピストン、９０は電子制御装置（ＥＣＵ）をそれぞれ示している。 <First Embodiment>
Hereinafter, embodiments of the present invention will be described with reference to the drawings. An internal combustion engine to which the fuel injection control device of the present invention is applied is shown in FIG. In FIG. 1, 10 is a body of an internal combustion engine (hereinafter referred to as “engine body”), 11 is a fuel injection valve, 12 is a cylinder head, 13 is a cylinder block, 14 is an intake valve, 15 is an exhaust valve, 16 is a spark plug, 17 Is an in-cylinder pressure sensor, 18 is a combustion chamber, 19 is a piston, and 90 is an electronic control unit (ECU).
　燃料噴射弁１１は、筒内（すなわち、燃焼室１８）上部の吸気弁１３側方の機関本体１０の部分（たとえば、シリンダヘッド１２の部分、または、シリンダブロック１３の部分）に取り付けられている。 The fuel injection valve 11 is attached to a part of the engine body 10 (for example, a part of the cylinder head 12 or a part of the cylinder block 13) on the side of the intake valve 13 in the upper part of the cylinder (that is, the combustion chamber 18). .
＜第１実施形態の燃料噴射弁の構成＞
　図２に燃料噴射弁１１の構成が示されている。図２において、３０はノズル、３１はニードル弁、３２は燃料噴射孔（以下「噴孔」）、３３は燃料通路、３４はソレノイド、３５はスプリング、３６は燃料取込口、３７は噴射弁軸線をそれぞれ示している。噴射弁軸線３７は、燃料噴射弁１１の長手方向に延びる軸線である。燃料噴射弁１１は、いわゆる内開弁タイプの燃料噴射弁である。燃料噴射弁１１は、フルリフト噴射とパーシャルリフト噴射とのいずれか一方を選択的に実行可能である。フルリフト噴射とは、図３（Ａ）に示されているように、ニードル弁３１を最大リフト量まで上昇させる燃料噴射（つまり、最大リフト噴射）であり、パーシャルリフト噴射とは、図３（Ｂ）に示されているように、ニードル弁３１を最大リフト量よりも小さいリフト量までしか上昇させない燃料噴射（つまり、部分リフト噴射）である。ニードルリフト量は、燃料噴射弁１１への通電時間の制御によって制御可能である。なお、図３（Ａ）には、１回のフルリフト噴射のニードルリフト量の推移が示されており、図３（Ｂ）には、３回のパーシャルリフト噴射のニードルリフト量の推移が示されている。 <Configuration of Fuel Injection Valve of First Embodiment>
FIG. 2 shows the configuration of the fuel injection valve 11. In FIG. 2, 30 is a nozzle, 31 is a needle valve, 32 is a fuel injection hole (hereinafter “injection hole”), 33 is a fuel passage, 34 is a solenoid, 35 is a spring, 36 is a fuel intake port, and 37 is an injection valve. Each axis is shown. The injection valve axis 37 is an axis extending in the longitudinal direction of the fuel injection valve 11. The fuel injection valve 11 is a so-called inner opening type fuel injection valve. The fuel injection valve 11 can selectively perform either full lift injection or partial lift injection. As shown in FIG. 3A, the full lift injection is a fuel injection that raises the needle valve 31 to the maximum lift amount (that is, the maximum lift injection), and the partial lift injection is the one shown in FIG. ), The fuel injection (that is, partial lift injection) that raises the needle valve 31 only to a lift amount smaller than the maximum lift amount. The needle lift amount can be controlled by controlling the energization time to the fuel injection valve 11. FIG. 3A shows the transition of the needle lift amount of one full lift injection, and FIG. 3B shows the transition of the needle lift amount of three partial lift injections. ing.
＜第１実施形態の噴孔およびその周辺の構成＞
　図４に第１実施形態の燃料噴射弁１１の噴孔３２およびその周辺の構成が示されている。図４（Ａ）は、燃料噴射弁１１の先端を噴射弁軸線３７に沿って燃料噴射弁１１の外から見た場合の燃料噴射弁１１の先端を示している。図４（Ｂ）は、図４（Ａ）の線Ｂ－Ｂの断面を示し、図４（Ｃ）は、図４（Ａ）の線Ｃ－Ｃの断面を示している。図４において、３０はノズル、３１はニードル弁、３２は噴孔、３７は噴射弁軸線、３８はサック、３９はニードルシート部（以下「シート部」）、４０はノズルシート壁面、４１はニードルシート壁面、４２は噴孔中央領域、４３は噴孔端部領域、４４は流入口、４５は流出口、４６はサック中心、４７は噴孔中央軸線、４８は噴孔端部軸線をそれぞれ示している。 <The structure of the nozzle hole of 1st Embodiment and its periphery>
FIG. 4 shows the structure of the injection hole 32 and its periphery of the fuel injection valve 11 of the first embodiment. FIG. 4A shows the tip of the fuel injection valve 11 when the tip of the fuel injection valve 11 is viewed from the outside of the fuel injection valve 11 along the injection valve axis 37. 4B shows a cross section taken along line BB in FIG. 4A, and FIG. 4C shows a cross section taken along line CC in FIG. 4A. In FIG. 4, 30 is a nozzle, 31 is a needle valve, 32 is an injection hole, 37 is an injection valve axis, 38 is a sack, 39 is a needle seat portion (hereinafter “sheet portion”), 40 is a nozzle seat wall surface, and 41 is a needle. The sheet wall surface, 42 is the nozzle hole central region, 43 is the nozzle hole end region, 44 is the inlet, 45 is the outlet, 46 is the sack center, 47 is the nozzle central axis, and 48 is the nozzle end axis. ing.
　サック中心４６は、サック３８を構成する空間の中心であって、噴射弁軸線３７上の点である。ノズルシート壁面４０は、燃料噴射弁１１が全閉状態になったとき（すなわち、ニードルリフト量が零になったとき）にニードルシート壁面４１が着座する壁面である。噴孔中央軸線４７は、燃料流れ方向（すなわち、噴孔内で燃料が流れる方向）に噴孔３２の中央を貫く軸線である。噴孔端部軸線４８は、燃料流れ方向に噴孔１３の端部を貫く軸線である。 The sack center 46 is the center of the space constituting the sack 38 and is a point on the injection valve axis 37. The nozzle seat wall surface 40 is a wall surface on which the needle seat wall surface 41 is seated when the fuel injection valve 11 is fully closed (that is, when the needle lift amount becomes zero). The nozzle hole central axis 47 is an axis that penetrates the center of the nozzle hole 32 in the fuel flow direction (that is, the direction in which fuel flows in the nozzle hole). The nozzle hole end axis 48 is an axis that penetrates the end of the nozzle hole 13 in the fuel flow direction.
＜噴孔の構成＞
　噴孔３２は、流入口４４と流出口４５とを有する。流入口４４はサック３８に対して開口しており、燃料は流入口４４を介して噴孔３２に流入する。流出口４５は燃料噴射弁１１の外部に対して開口しており、燃料は流出口４５から噴射される。噴孔３２の内部領域は、噴孔中央領域４２と噴孔端部領域４３とに分けられる。噴孔中央領域４２は、噴孔中央軸線４７に沿って流入口４４から流出口４５まで延在する領域である。噴孔端部領域４３は、噴孔中央領域４２の両側において、各噴孔端部軸線４８に沿って流入口４４から流出口４５まで延在する領域である。 <Configuration of nozzle hole>
The nozzle hole 32 has an inlet 44 and an outlet 45. The inlet 44 is open to the sack 38, and the fuel flows into the injection hole 32 through the inlet 44. The outlet 45 is open to the outside of the fuel injection valve 11, and the fuel is injected from the outlet 45. The inner region of the nozzle hole 32 is divided into a nozzle hole central region 42 and a nozzle hole end region 43. The nozzle hole central region 42 is a region extending from the inlet 44 to the outlet 45 along the nozzle central axis 47. The nozzle hole end region 43 is a region that extends from the inlet 44 to the outlet 45 along each nozzle hole end axis 48 on both sides of the nozzle hole central region 42.
＜噴孔の形状＞
　図４（Ａ）に示されているように、噴孔３２をその横断面で見たとき、噴孔３２は、矩形の横断面を有する。ここで、噴孔の横断面とは、噴孔中央軸線４７に対して垂直な平面で噴孔を切った場合の断面である。また、図４（Ｂ）に示されているように、噴孔３２を断面Ｂ－Ｂで見たとき、噴孔３２は、流入口４４から流出口４５に向かって広がる扇形の形状を有する。したがって、噴孔３２の流路断面は、流入口４４から流出口４５に向かって徐々に大きくなる。もちろん、流出口４５の流路面積は、流入口４４の流路面積よりも大きい。なお、断面Ｂ－Ｂは、噴孔中央軸線４７と各噴孔端部軸線４８とを含む１つの平面で噴孔を切った場合の断面である。また、図４（Ｃ）に示されているように、噴孔３２をその縦断面で見たとき、噴孔３２は、略矩形の形状を有する。ここで、噴孔の縦断面とは、噴孔中央軸線４７と噴射弁軸線３７とを含む１つの平面で切った場合の断面である。 <Shape of nozzle hole>
As shown in FIG. 4A, when the injection hole 32 is viewed in its cross section, the injection hole 32 has a rectangular cross section. Here, the cross section of the injection hole is a cross section when the injection hole is cut along a plane perpendicular to the injection hole central axis 47. Further, as shown in FIG. 4B, when the nozzle hole 32 is viewed in cross section BB, the nozzle hole 32 has a fan-shaped shape that spreads from the inlet 44 toward the outlet 45. Therefore, the flow path cross section of the nozzle hole 32 gradually increases from the inlet 44 toward the outlet 45. Of course, the channel area of the outlet 45 is larger than the channel area of the inlet 44. The cross section BB is a cross section when the nozzle hole is cut along one plane including the nozzle hole central axis 47 and each nozzle hole end axis 48. Moreover, as shown in FIG. 4C, when the nozzle hole 32 is viewed in its longitudinal section, the nozzle hole 32 has a substantially rectangular shape. Here, the vertical cross section of the injection hole is a cross section when cut along one plane including the injection hole central axis 47 and the injection valve axis 37.
＜噴孔の位置＞
　また、図４（Ｂ）および図４（Ｃ）に示されているように、噴孔３２は、噴孔中央軸線４７および噴孔端部軸線４８がサック中心４６と交差するようにノズル３０の先端に形成されている。また、噴孔３２は、噴孔中央軸線４７が噴射弁軸線３７に対して一定の角度をもつようにノズル３０の先端に形成されている。なお、噴孔は、噴孔中央軸線４７が噴射弁軸線３７に一致するようにノズル３０の先端に形成されていてもよい。 <Position of nozzle hole>
Also, as shown in FIGS. 4B and 4C, the nozzle hole 32 is formed so that the nozzle hole center axis 47 and the nozzle hole end axis 48 intersect the sack center 46. It is formed at the tip. The injection hole 32 is formed at the tip of the nozzle 30 so that the injection hole central axis 47 has a certain angle with respect to the injection valve axis 37. The injection hole may be formed at the tip of the nozzle 30 such that the injection hole central axis 47 coincides with the injection valve axis 37.
＜噴霧内の燃料流量分布＞
　第１実施形態の燃料噴射弁１１から噴射される燃料噴霧（以下「噴霧」）が図５に示されている。図５は、燃料噴射弁１１の先端を噴射弁軸線３７に沿って燃料噴射弁１１の外から見た場合の噴霧を示している。図５（Ａ）はフルリフト噴射時の噴霧を示し、図５（Ｂ）はパーシャルリフト噴射時の噴霧を示している。図５において、５０は噴孔中央領域４２から流出口４５を介して噴射された噴霧（以下「噴霧中央部」）であり、５１は噴孔端部領域４３から流出口４５を介して噴射された噴霧（以下「噴霧端部」）である。 <Fuel flow distribution in the spray>
FIG. 5 shows fuel spray injected from the fuel injection valve 11 of the first embodiment (hereinafter referred to as “spray”). FIG. 5 shows spraying when the tip of the fuel injection valve 11 is viewed from the outside of the fuel injection valve 11 along the injection valve axis 37. FIG. 5A shows spray during full lift injection, and FIG. 5B shows spray during partial lift injection. In FIG. 5, 50 is spray sprayed from the nozzle hole center region 42 through the outlet 45 (hereinafter “spray center part”), and 51 is sprayed from the nozzle hole end region 43 through the outlet 45. Spray (hereinafter “spray end”).
　図５に示されているように、第１実施形態の燃料噴射弁１１では、フルリフト噴射時の噴霧中央部５０の燃料流量（図５（Ａ）参照）は、パーシャルリフト噴射時の噴霧中央部５０の燃料流量（図５（Ｂ）参照）よりも少ない。すなわち、フルリフト噴射時の全噴射量に占める噴孔中央領域からの噴射量の割合は、パーシャルリフト噴射時の全噴射量に占める噴孔中央領域からの噴射量の割合よりも小さい。また、フルリフト噴射時の噴孔端部５１の燃料流量（図５（Ａ）参照）は、パーシャルリフト噴射時の噴霧端部５１の燃料流量（図５（Ｂ）参照）よりも多い。すなわち、フルリフト噴射時の全噴射量に占める噴孔端部領域からの噴射量の割合は、パーシャルリフト噴射時の全噴射量に占める噴孔端部領域からの噴射量の割合よりも大きい。 As shown in FIG. 5, in the fuel injection valve 11 of the first embodiment, the fuel flow rate (see FIG. 5A) of the spray central portion 50 at the time of full lift injection is the spray central portion at the time of partial lift injection. Less than 50 fuel flow rates (see FIG. 5B). That is, the ratio of the injection amount from the nozzle hole central region to the total injection amount at the time of full lift injection is smaller than the ratio of the injection amount from the nozzle hole central region to the total injection amount at the time of partial lift injection. Further, the fuel flow rate at the nozzle hole end 51 during full lift injection (see FIG. 5A) is larger than the fuel flow rate at the spray end 51 during partial lift injection (see FIG. 5B). That is, the ratio of the injection amount from the nozzle hole end region to the total injection amount at the time of full lift injection is larger than the ratio of the injection amount from the nozzle hole end region to the total injection amount at the time of partial lift injection.
＜第１実施形態の噴霧角度および貫徹力＞
　図６に示されているように、第１実施形態の燃料噴射弁１１では、フルリフト噴射時の噴霧角度５２（図６（Ａ）参照）は、パーシャルリフト噴射時の噴霧角度５２（図６（Ｂ）参照）よりも大きい。また、フルリフト噴射時の貫徹力は、パーシャルリフト噴射時の貫徹力よりも大きい。なお、噴霧角度５２は噴霧の外縁５３間の角度であり、貫徹力は噴霧が筒内を進む力である。 <The spray angle and penetration force of the first embodiment>
As shown in FIG. 6, in the fuel injection valve 11 of the first embodiment, the spray angle 52 during full lift injection (see FIG. 6A) is the same as the spray angle 52 during partial lift injection (see FIG. Larger than B). Moreover, the penetration force at the time of full lift injection is larger than the penetration force at the time of partial lift injection. The spray angle 52 is the angle between the outer edges 53 of the spray, and the penetration force is the force that the spray travels in the cylinder.
＜第１実施形態の燃料噴射制御＞
　第１実施形態の燃料噴射制御について説明する。上述したように、第１実施形態の燃料噴射弁では、フルリフト噴射時の噴霧中央部の燃料流量（図５（Ａ）参照）は、パーシャルリフト噴射時の噴霧中央部の燃料流量（図５（Ｂ）参照）よりも多い。一方、フルリフト噴射時の噴霧端部の燃料流量（図５（Ａ）参照）は、パーシャルリフト噴射時の噴霧端部の燃料流量（図５（Ｂ）参照）よりも少ない。そこで、第１実施形態では、こうしたニードルリフト量と噴霧内の燃料流量分布との関係に鑑み、フルリフト噴射制御中に燃焼状態が所定の燃焼状態よりも悪化した場合、噴射制御がフルリフト噴射制御からパーシャルリフト噴射制御に切り替えられる。 <Fuel Injection Control of First Embodiment>
The fuel injection control of the first embodiment will be described. As described above, in the fuel injection valve according to the first embodiment, the fuel flow rate at the center of the spray at the time of full lift injection (see FIG. 5A) is the fuel flow rate at the center of the spray at the time of partial lift injection (see FIG. More than B). On the other hand, the fuel flow rate at the spray end during full lift injection (see FIG. 5A) is smaller than the fuel flow rate at the spray end during partial lift injection (see FIG. 5B). Therefore, in the first embodiment, in view of the relationship between the needle lift amount and the fuel flow distribution in the spray, when the combustion state becomes worse than the predetermined combustion state during the full lift injection control, the injection control is changed from the full lift injection control. It is switched to partial lift injection control.
　なお、フルリフト噴射制御とは、所定のタイミング（具体的には、圧縮上死点近傍のタイミング）においてフルリフト噴射を実行する制御であり、パーシャルリフト噴射制御とは、所定のタイミング（具体的には、圧縮上死点近傍のタイミング）においてパーシャルリフト噴射を実行する制御である。 The full lift injection control is a control for executing full lift injection at a predetermined timing (specifically, a timing near the compression top dead center), and the partial lift injection control is a predetermined timing (specifically, In this case, the partial lift injection is executed at a timing near the compression top dead center.
　また、噴射制御がフルリフト噴射制御からパーシャルリフト噴射制御に切り替えられる場合、切替前後の総燃料噴射量が同量に維持されることが好ましい。すなわち、切替後の総燃料噴射量（すなわち、パーシャルリフト噴射制御中の総燃料噴射量）が切替前の総燃料噴射量（すなわち、フルリフト噴射制御中の総燃料噴射量）と同量に維持されることが好ましい。ここで、総燃料噴射量とは、１機関サイクル当たりに燃料噴射弁が噴射される燃料の総量である。そして、切替前後の総燃料噴射量を同量に維持する手段として、たとえば、パーシャルリフト噴射制御での１機関サイクル当たりの噴射回数を増やすという手段を採用可能である。 Also, when the injection control is switched from the full lift injection control to the partial lift injection control, it is preferable that the total fuel injection amount before and after the switching is maintained at the same amount. That is, the total fuel injection amount after switching (that is, the total fuel injection amount during partial lift injection control) is maintained at the same amount as the total fuel injection amount before the switching (that is, total fuel injection amount during full lift injection control). It is preferable. Here, the total fuel injection amount is the total amount of fuel injected by the fuel injection valve per engine cycle. As a means for maintaining the same total fuel injection amount before and after switching, for example, a means for increasing the number of injections per engine cycle in the partial lift injection control can be employed.
＜第１実施形態の燃料噴射制御の利点１＞
　上述した直噴タイプの内燃機関（すなわち、燃料噴射弁から筒内に燃料を直接噴射するタイプの内燃機関）において、フルリフト噴射制御中に燃焼状態が悪化した場合、その悪化の原因の１つとして、噴霧内の燃料流量分布が挙げられる。すなわち、第１実施形態の燃料噴射弁では、フルリフト噴射時は、噴霧端部の燃料流量が多い。このため、その時の機関運転状態においては、噴霧端部の燃料の微粒化度合が悪く、したがって、噴霧端部の燃料が燃焼しづらく（すなわち、噴霧端部の燃料の燃焼が進みづらく、つまり、噴霧端部の燃料の燃焼速度が遅く）、全体として、均質度の高い混合気が筒内に形成されていない可能性がある。つまり、噴霧内の燃料流量分布が均質度の高い混合気を形成するのには好ましくない分布になっている可能性がある。 <Advantage 1 of Fuel Injection Control of First Embodiment>
In the above-described direct injection type internal combustion engine (that is, an internal combustion engine that directly injects fuel into a cylinder from a fuel injection valve), if the combustion state deteriorates during full lift injection control, one of the causes of the deterioration And fuel flow distribution in the spray. That is, in the fuel injection valve of the first embodiment, the fuel flow rate at the spray end is large during full lift injection. For this reason, in the engine operation state at that time, the atomization degree of the fuel at the spray end is poor, and therefore, the fuel at the spray end is difficult to burn (that is, the combustion of the fuel at the spray end is difficult to proceed, that is, The combustion speed of the fuel at the spray end is slow), and as a whole, there is a possibility that an air-fuel mixture with high homogeneity is not formed in the cylinder. That is, there is a possibility that the fuel flow rate distribution in the spray is unfavorable for forming a mixture with high homogeneity.
　一方、第１実施形態の燃料噴射弁では、ニードルリフト量の変更によって噴霧内の燃料流量分布が変わる。具体的には、噴射制御をフルリフト噴射制御からパーシャルリフト噴射制御に切り替えることによって、噴霧端部の燃料流量が少なくなる。したがって、フルリフト噴射制御中に燃焼状態が悪化した場合に噴射制御がパーシャルリフト噴射制御に切り替えられれば、少なからず、噴霧端部の燃料の微粒化度合が向上する可能性が高い。すなわち、噴霧内の燃料流量分布が均質度の高い混合気を形成するのに適した分布になる可能性が高い。このため、第１実施形態によれば、燃焼状態の悪化を改善することができる。 On the other hand, in the fuel injection valve of the first embodiment, the fuel flow rate distribution in the spray changes by changing the needle lift amount. Specifically, the fuel flow rate at the spray end is reduced by switching the injection control from full lift injection control to partial lift injection control. Accordingly, if the injection control is switched to the partial lift injection control when the combustion state deteriorates during the full lift injection control, there is a high possibility that the degree of atomization of the fuel at the spray end is improved. That is, there is a high possibility that the fuel flow rate distribution in the spray becomes a distribution suitable for forming an air-fuel mixture with high homogeneity. For this reason, according to 1st Embodiment, the deterioration of a combustion state can be improved.
＜第１実施形態の燃料噴射制御の利点２＞
　また、当然のことながら、１回のフルリフト噴射による燃料噴射量は、１回のパーシャルリフト噴射による燃料噴射量よりも多い。このため、全体として、フルリフト噴射時の燃料の微粒化度合は、パーシャルリフト噴射時の燃料の微粒化度合よりも低い。したがって、フルリフト噴射制御中に燃焼状態が所定の燃焼状態よりも悪化した場合に、燃料噴射がフルリフト噴射制御からパーシャルリフト噴射制御に切り替えられれば、１回の燃料噴射当たりの燃料噴射量が少なくなる。この理由からも、第１実施形態によれば、燃焼状態の悪化を改善することができる。 <Advantage 2 of Fuel Injection Control of First Embodiment>
Of course, the fuel injection amount by one full lift injection is larger than the fuel injection amount by one partial lift injection. For this reason, as a whole, the degree of atomization of fuel at the time of full lift injection is lower than the degree of atomization of fuel at the time of partial lift injection. Therefore, when the combustion state is worse than the predetermined combustion state during the full lift injection control, if the fuel injection is switched from the full lift injection control to the partial lift injection control, the fuel injection amount per fuel injection is reduced. . Also for this reason, according to the first embodiment, the deterioration of the combustion state can be improved.
＜第１実施形態の追加の燃料噴射制御１＞
　なお、第１実施形態の燃料噴射制御において、パーシャルリフト噴射制御中に燃焼状態が所定の燃焼状態よりも悪化したか否かにかかわらず、パーシャルリフト噴射制御が継続されてもよい。しかしながら、パーシャルリフト噴射制御中に燃焼状態が所定の燃焼状態よりも悪化した場合、噴射制御をパーシャルリフト噴射制御からフルリフト噴射制御に切り替えることが好ましい。これによれば、以下の利点が得られる。 <Additional Fuel Injection Control 1 of First Embodiment>
Note that, in the fuel injection control of the first embodiment, the partial lift injection control may be continued regardless of whether or not the combustion state is worse than the predetermined combustion state during the partial lift injection control. However, when the combustion state becomes worse than the predetermined combustion state during the partial lift injection control, it is preferable to switch the injection control from the partial lift injection control to the full lift injection control. According to this, the following advantages can be obtained.
　上述した直噴タイプの内燃機関において、パーシャルリフト噴射制御中に燃焼状態が悪化した場合、その悪化の原因の１つとして、噴霧内の燃料流量分布が挙げられる。すなわち、第１実施形態の燃料噴射弁では、パーシャルリフト噴射時は、噴霧端部の燃料流量が少ない。このため、その時の機関運転状態において、噴霧端部の燃料の燃焼のしづらさ（すなわち、噴霧端部の燃料の燃焼が進みづらいこと、つまり、噴霧端部の燃料の燃焼速度が遅いこと）が考えられる。 In the above-described direct injection type internal combustion engine, when the combustion state deteriorates during partial lift injection control, one of the causes of the deterioration is the fuel flow rate distribution in the spray. That is, in the fuel injection valve of the first embodiment, the fuel flow rate at the spray end is small during partial lift injection. For this reason, in the engine operating state at that time, it is difficult to burn the fuel at the spray end (that is, it is difficult to burn the fuel at the spray end, that is, the combustion speed of the fuel at the spray end is slow). Can be considered.
　一方、第１実施形態の燃料噴射弁では、ニードルリフト量の変更によって噴霧内の燃料流量分布が変わる。具体的には、噴射制御をパーシャルリフト噴射制御からフルリフト噴射制御に切り替えることによって、噴霧端部の燃料流量が多くなる。したがって、パーシャルリフト噴射制御中に燃焼状態が悪化した場合に噴射制御がフルリフト噴射制御に切り替えられれば、少なからず、噴霧端部の燃料の燃焼速度が向上する可能性が高い。このため、パーシャルリフト噴射制御中に燃焼状態が所定の燃焼状態よりも悪化した場合に、噴射制御をパーシャルリフト噴射制御からフルリフト噴射制御に切り替えることによって、燃焼状態の悪化を改善することができるという利点が得られる。 On the other hand, in the fuel injection valve of the first embodiment, the fuel flow rate distribution in the spray changes by changing the needle lift amount. Specifically, the fuel flow rate at the spray end is increased by switching the injection control from the partial lift injection control to the full lift injection control. Therefore, if the injection control is switched to the full lift injection control when the combustion state deteriorates during the partial lift injection control, it is highly possible that the combustion speed of the fuel at the spray end portion is improved. For this reason, when the combustion state becomes worse than the predetermined combustion state during the partial lift injection control, the deterioration of the combustion state can be improved by switching the injection control from the partial lift injection control to the full lift injection control. Benefits are gained.
　なお、噴射制御がパーシャルリフト噴射制御からフルリフト噴射制御に切り替えられる場合、切替前後の総燃料噴射量が同量に維持されることが好ましい。すなわち、切替後の総燃料噴射量（すなわち、フルリフト噴射制御中の総燃料噴射量）が切替前の総燃料噴射量（すなわち、パーシャルリフト噴射制御中の総燃料噴射量）と同量に維持されることが好ましい。 In addition, when the injection control is switched from the partial lift injection control to the full lift injection control, it is preferable that the total fuel injection amount before and after the switching is maintained at the same amount. That is, the total fuel injection amount after switching (that is, the total fuel injection amount during full lift injection control) is maintained at the same amount as the total fuel injection amount before the switching (that is, total fuel injection amount during partial lift injection control). It is preferable.
＜第１実施形態の追加の燃料噴射制御２＞
　また、第１実施形態の燃料噴射制御において、パーシャルリフト噴射制御中に燃焼状態が所定の燃焼状態である場合、パーシャルリフト噴射制御が継続されてもよい。しかしながら、パーシャルリフト噴射制御中に燃焼状態が所定の燃焼状態であるときに噴射制御をパーシャルリフト噴射制御からフルリフト噴射制御に切り替えたとしても燃焼状態が所定の燃焼状態に維持される場合、噴射制御をパーシャルリフト噴射制御からフルリフト噴射制御に切り替えることが好ましい。これによれば、以下の利点が得られる。 <Additional Fuel Injection Control 2 of First Embodiment>
In the fuel injection control of the first embodiment, when the combustion state is a predetermined combustion state during the partial lift injection control, the partial lift injection control may be continued. However, when the combustion state is maintained in the predetermined combustion state even if the injection control is switched from the partial lift injection control to the full lift injection control when the combustion state is the predetermined combustion state during the partial lift injection control, the injection control is performed. Is preferably switched from partial lift injection control to full lift injection control. According to this, the following advantages can be obtained.
　噴孔にデポジットが堆積することがある。そして、第１実施形態の燃料噴射弁のように、噴孔がスリット形状である場合、多くのデポジットは、噴孔の端部領域の壁面（別の言い方をすると、噴孔の幅方向の端部壁面）に堆積する。一方、フルリフト噴射によれば、パーシャルリフト噴射に比べて、噴孔の端部領域（別の言い方をすると、噴孔の幅方向の端部壁面近傍）を流れる燃料流量が多い。したがって、パーシャルリフト噴射制御中に燃焼状態が所定の燃焼状態であるときに噴射制御をパーシャルリフト噴射制御からフルリフト噴射制御に切り替えたとしても燃焼状態が所定の燃焼状態に維持される場合、噴射制御をパーシャルリフト噴射制御からフルリフト噴射制御に切り替えることによって（すなわち、燃焼状態が所定の燃焼状態に維持される限り、フルリフト噴射制御を実行することによって）、噴孔に堆積したデポジットを除去することができるとともに、噴孔へのデポジットの堆積を抑制することができるという利点が得られる。 Deposits may accumulate in the nozzle hole. And, like the fuel injection valve of the first embodiment, when the injection hole has a slit shape, many deposits are formed on the wall surface of the end region of the injection hole (in other words, the end of the injection hole in the width direction). Deposited on the wall). On the other hand, according to full lift injection, the flow rate of fuel flowing through the end region of the injection hole (in other words, in the vicinity of the end wall surface in the width direction of the injection hole) is larger than in partial lift injection. Therefore, if the combustion state is maintained in the predetermined combustion state even when the injection control is switched from the partial lift injection control to the full lift injection control when the combustion state is the predetermined combustion state during the partial lift injection control, the injection control Is switched from partial lift injection control to full lift injection control (that is, by performing full lift injection control as long as the combustion state is maintained at a predetermined combustion state), deposits accumulated in the nozzle holes can be removed. In addition, it is possible to obtain an advantage that deposit accumulation in the nozzle hole can be suppressed.
　なお、デポジットとは、筒内の燃焼によって生成される物質であり、たとえば、燃料や潤滑油などの未燃物である。 The deposit is a substance generated by in-cylinder combustion, for example, an unburned material such as fuel or lubricating oil.
　なお、燃焼状態は、たとえば、トルク変動量、筒内圧の変動量、機関回転数の変動量、排気温度、排気性状（たとえば、未燃ＨＣ量など）によって把握可能である。具体的には、トルク変動量が所定量よりも大きいとき、あるいは、筒内圧の変動量が所定量よりも大きいとき、あるいは、機関回転数の変動量が所定量よりも大きいとき、あるいは、排気温度が所定温度よりも低いとき、あるいは、排気性状が所定性状よりも悪化しているとき（たとえば、未燃ＨＣ量が所定量よりも多いとき）に、燃焼状態が所定の燃焼状態よりも悪化していると判断することができる。なお、燃焼状態を代表するこうしたパラメータを検出する場合、その検出は、機関運転が定常運転状態にあるときに行われることが好ましい。また、トルク変動量とは、機関出力トルクの変動量であり、筒内圧の変動量とは、特定クランク角度における筒内の圧力（または、筒内の圧力の最大値）の変動量である。 The combustion state can be grasped by, for example, the torque fluctuation amount, the in-cylinder pressure fluctuation amount, the engine speed fluctuation amount, the exhaust temperature, and the exhaust properties (for example, the unburned HC amount). Specifically, when the torque fluctuation amount is larger than a predetermined amount, or when the in-cylinder pressure fluctuation amount is larger than a predetermined amount, or when the engine rotational speed fluctuation amount is larger than a predetermined amount, or the exhaust When the temperature is lower than the predetermined temperature, or when the exhaust property is worse than the predetermined property (for example, when the unburned HC amount is larger than the predetermined amount), the combustion state is worse than the predetermined combustion state. It can be determined that When detecting such a parameter representative of the combustion state, the detection is preferably performed when the engine operation is in a steady operation state. The torque fluctuation amount is the fluctuation amount of the engine output torque, and the fluctuation amount of the in-cylinder pressure is the fluctuation amount of the in-cylinder pressure (or the maximum value of the in-cylinder pressure) at the specific crank angle.
　また、燃焼状態は、たとえば、失火によっても把握可能である。すなわち、内燃機関が筒内の失火を検出する手段（たとえば、失火センサ）を有している場合、失火が生じているとき、あるいは、所定時間内の失火の回数が所定回数よりも多いときに、燃焼状態が所定の燃焼状態よりも悪化していると判断することができる。 Also, the combustion state can be grasped by misfire, for example. That is, when the internal combustion engine has means for detecting misfire in the cylinder (for example, misfire sensor), when misfire occurs, or when the number of misfires within a predetermined time is greater than the predetermined number It can be determined that the combustion state is worse than the predetermined combustion state.
＜第１実施形態の燃料噴射制御フロー１＞
　第１実施形態の燃料噴射制御フローの一例が図７に示されている。このフローは、所定時間が経過する毎に実行される。このフローが開始されると、始めに、ステップ１０において、目標燃料噴射量Ｑが決定される。次いで、ステップ１１において、トルク変動量ＣＴが所定量ＣＴｔｈよりも大きい（ＣＴ＞ＣＴｔｈ）か否かが判別される。ここで、ＣＴ＞ＣＴｔｈではないと判別されたときには、フローはそのまま終了する。この場合、現在の噴射制御が継続される。一方、ＣＴ＞ＣＴｔｈであると判別されたときには、ステップ１２において、フルリフトフラグＦｆがセットされている（Ｆｆ＝１）か否かが判別される。このフラグＦｆは、フルリフト噴射制御が実行されているときにセットされ、パーシャルリフト噴射制御が実行されているときにリセットされるフラグである。 <Fuel Injection Control Flow 1 of First Embodiment>
An example of the fuel injection control flow of the first embodiment is shown in FIG. This flow is executed every time a predetermined time elapses. When this flow is started, first, at step 10, the target fuel injection amount Q is determined. Next, at step 11, it is determined whether or not the torque fluctuation amount CT is larger than a predetermined amount CTth (CT> CTth). Here, when it is determined that CT> CTth is not satisfied, the flow ends as it is. In this case, the current injection control is continued. On the other hand, if it is determined that CT> CTth, it is determined in step 12 whether or not the full lift flag Ff is set (Ff = 1). This flag Ff is a flag that is set when the full lift injection control is being executed, and is reset when the partial lift injection control is being executed.
　ステップ１２において、Ｆｆ＝１であると判別されたとき（すなわち、フルリフト噴射制御が実行されているとき）には、ステップ１３において、パーシャルリフト量（すなわち、１回のパーシャルリフト噴射におけるニードルリフト量）Ｌｐが決定される。次いで、ステップ１４において、ステップ１０で決定された目標燃料噴射量Ｑとステップ１３で決定されたパーシャルリフト量Ｌｐとに基づいて噴射回数Ｎｐが決定される。すなわち、ステップ１３で決定されたパーシャルリフト量Ｌｐのパーシャルリフト噴射によって、ステップ１０で決定された目標燃料噴射量Ｑの燃料を噴射するために必要なパーシャルリフト噴射の回数が決定される。次いで、ステップ１５において、噴射制御がフルリフト噴射制御からパーシャルリフト噴射制御に切り替えられ、フローが終了する。この場合、ステップ１５において噴射制御が切り替えられた後は、各気筒の各機関サイクルにおいて、ステップ１３で決定されたパーシャルリフト量Ｌｐでのパーシャルリフト噴射がステップ１４で決定された噴射回数Ｎｐだけ実行される。 When it is determined in step 12 that Ff = 1 (that is, when the full lift injection control is being executed), in step 13, the partial lift amount (that is, the needle lift amount in one partial lift injection). ) Lp is determined. Next, at step 14, the number of injections Np is determined based on the target fuel injection amount Q determined at step 10 and the partial lift amount Lp determined at step 13. That is, the number of partial lift injections required to inject the fuel of the target fuel injection amount Q determined in step 10 is determined by the partial lift injection of the partial lift amount Lp determined in step 13. Next, at step 15, the injection control is switched from full lift injection control to partial lift injection control, and the flow ends. In this case, after the injection control is switched in step 15, the partial lift injection at the partial lift amount Lp determined in step 13 is executed for the number of injections Np determined in step 14 in each engine cycle of each cylinder. Is done.
　一方、ステップ１２において、Ｆｆ＝１ではないと判別されたとき（すなわち、パーシャルリフト噴射制御が実行されているとき）には、ステップ１６において、噴射制御がパーシャルリフト噴射制御からフルリフト噴射制御に切り替えられ、フローが終了する。この場合、ステップ１６で噴射制御が切り替えられた後は、各気筒の各機関サイクルにおいて、ステップ１０で決定された目標燃料噴射量Ｑの燃料が噴射されるようにフルリフト噴射が実行される。 On the other hand, when it is determined in step 12 that Ff = 1 is not satisfied (that is, when partial lift injection control is being executed), in step 16, the injection control is switched from partial lift injection control to full lift injection control. And the flow ends. In this case, after the injection control is switched in step 16, full lift injection is executed so that fuel of the target fuel injection amount Q determined in step 10 is injected in each engine cycle of each cylinder.
＜第１実施形態の燃料噴射制御フロー２＞
　第１実施形態の燃料噴射制御フローの別の一例が図８および図９に示されている。このフローは、所定時間が経過する毎に実行される。なお、このフローのステップ１１～ステップ１６は、図７のフローのステップ１１～ステップ１６と同じであるので、これらステップの説明は省略する。 <Fuel Injection Control Flow 2 of First Embodiment>
Another example of the fuel injection control flow of the first embodiment is shown in FIGS. This flow is executed every time a predetermined time elapses. Since steps 11 to 16 of this flow are the same as steps 11 to 16 of the flow of FIG. 7, description of these steps is omitted.
　図８のステップ１１において、ＣＴ＞ＣＴｔｈではないと判別されたときには、ステップ２０において、フルリフトフラグＦｆがセットされている（Ｆｆ＝１）か否かが判別される。このフラグＦｆは、ステップ１２のフラグＦｆと同じフラグである。 When it is determined in step 11 of FIG. 8 that CT> CTth is not satisfied, it is determined in step 20 whether the full lift flag Ff is set (Ff = 1). This flag Ff is the same flag as the flag Ff in step 12.
　ステップ２０において、Ｆｆ＝１であると判別されたとき（すなわち、フルリフト噴射制御が実行されているとき）には、フローはそのまま終了する。一方、Ｆｆ＝１ではないと判別されたとき（すなわち、パーシャルリフト噴射制御が実行されているとき）には、ステップ２１において、噴射制御がパーシャルリフト噴射制御からフルリフト噴射制御に切り替えられる。この場合、ステップ２１において噴射制御が切り替えられた後は、各気筒の各機関サイクルにおいて、ステップ１０で決定された目標燃料噴射量Ｑの燃料が噴射されるようにフルリフト噴射が実行される。 When it is determined in step 20 that Ff = 1 (that is, when full lift injection control is being executed), the flow ends as it is. On the other hand, when it is determined that Ff = 1 is not satisfied (that is, when partial lift injection control is being executed), in step 21, the injection control is switched from partial lift injection control to full lift injection control. In this case, after the injection control is switched in step 21, full lift injection is executed so that fuel of the target fuel injection amount Q determined in step 10 is injected in each engine cycle of each cylinder.
　次いで、ステップ２２において、トルク変動量ＣＴが所定量ＣＴｔｈよりも大きい（ＣＴ＞ＣＴｔｈ）か否かが判別される。ここで、ＣＴ＞ＣＴｔｈではないと判別されたときには、フローはそのまま終了する。この場合、ステップ２１で噴射制御がフルリフト噴射制御に切り替えられているので、フルリフト噴射制御が継続される。一方、ＣＴ＞ＣＴｔｈであると判別されたときには、ステップ２３において、パーシャルリフト量Ｌｐが決定される。次いで、ステップ２４において、ステップ１０で決定された目標燃料噴射量Ｑとステップ２３で決定されたパーシャルリフト量Ｌｐとに基づいて噴射回数Ｎｐが決定される。すなわち、ステップ２３で決定されたパーシャルリフト量Ｌｐのパーシャルリフト噴射によって、ステップ１０で決定された目標燃料噴射量Ｑの燃料を噴射するために必要なパーシャルリフト噴射の回数が決定される。次いで、ステップ２５において、噴射制御がフルリフト噴射制御からパーシャルリフト噴射制御に切り替えられ、フローが終了する。この場合、ステップ２５において噴射制御が切り替えられた後は、各気筒の各機関サイクルにおいて、ステップ２３で決定されたパーシャルリフト量Ｌｐでのパーシャルリフト噴射がステップ２４で決定された噴射回数Ｎｐだけ実行される。 Next, at step 22, it is determined whether or not the torque fluctuation amount CT is larger than a predetermined amount CTth (CT> CTth). Here, when it is determined that CT> CTth is not satisfied, the flow ends as it is. In this case, since the injection control is switched to the full lift injection control in step 21, the full lift injection control is continued. On the other hand, if it is determined that CT> CTth, the partial lift amount Lp is determined in step 23. Next, at step 24, the number of injections Np is determined based on the target fuel injection amount Q determined at step 10 and the partial lift amount Lp determined at step 23. That is, the number of partial lift injections required to inject the fuel of the target fuel injection amount Q determined in step 10 is determined by the partial lift injection of the partial lift amount Lp determined in step 23. Next, in step 25, the injection control is switched from full lift injection control to partial lift injection control, and the flow ends. In this case, after the injection control is switched in step 25, the partial lift injection at the partial lift amount Lp determined in step 23 is executed for the number of injections Np determined in step 24 in each engine cycle of each cylinder. Is done.
　つまり、このフローのステップ２０～ステップ２５では、パーシャルリフト噴射制御中にトルク変動量が所定量以下である場合、いったん、噴射制御がフルリフト噴射制御に切り替えられ、その後のトルク変動量が所定量以下であれば、そのまま、フルリフト噴射制御が継続される一方、トルク変動量が所定量よりも大きければ、噴射制御がパーシャルリフト噴射制御に戻される。 That is, in step 20 to step 25 of this flow, when the torque fluctuation amount is equal to or less than the predetermined amount during the partial lift injection control, the injection control is once switched to the full lift injection control, and the subsequent torque fluctuation amount is equal to or less than the predetermined amount. Then, the full lift injection control is continued as it is, while if the torque fluctuation amount is larger than the predetermined amount, the injection control is returned to the partial lift injection control.
＜第２実施形態＞
　第２実施形態について説明する。以下で説明されない第２実施形態の構成および制御は、それぞれ、第１実施形態の構成および制御と同じであるか、あるいは、以下で説明する第２実施形態の構成または制御に鑑みたときに第１実施形態の構成または制御から当然に導き出される構成および制御である。 Second Embodiment
A second embodiment will be described. The configuration and control of the second embodiment not described below are the same as the configuration and control of the first embodiment, respectively, or when considering the configuration or control of the second embodiment described below. The configuration and control are naturally derived from the configuration or control of the embodiment.
＜第２実施形態の燃料噴射制御＞
　第２実施形態では、高負荷低回転時であってフルリフト噴射制御中に燃焼状態が所定の燃焼状態よりも悪化した場合、噴射制御がフルリフト噴射制御からパーシャルリフト噴射制御に切り替えるられる。 <Fuel Injection Control of Second Embodiment>
In the second embodiment, the injection control is switched from the full lift injection control to the partial lift injection control when the combustion state is worse than the predetermined combustion state during full lift injection control at the time of high load and low rotation.
＜第２実施形態の燃料噴射制御の利点＞
　第１実施形態に関連して説明したように、フルリフト噴射制御中に燃焼状態が悪化した場合、その悪化の原因の１つとして、噴霧端部の燃料の微粒化度合の低下が挙げられる。そして、この噴霧端部の燃料の微粒化度合の低下は、高負荷低回転時において顕著になる。つまり、高負荷低回転時のフルリフト噴射制御中に燃焼状態が悪化した場合、その悪化の原因が噴霧内の燃料流量分布である可能性が高い。したがって、このときに噴射制御がパーシャルリフト噴射制御に切り替えられれば、噴霧端部の燃料の微粒化度合が向上する可能性が非常に高い。すなわち、噴霧内の燃料流量分布が均質度の高い混合気を形成するのに適した分布になる可能性が非常に高い。このため、第２実施形態によれば、燃焼状態の悪化をより確実に改善することができる。 <Advantages of Fuel Injection Control of Second Embodiment>
As described in relation to the first embodiment, when the combustion state deteriorates during the full lift injection control, one cause of the deterioration is a decrease in the atomization degree of the fuel at the spray end. And the fall of the atomization degree of the fuel of this spray end part becomes remarkable at the time of high load low rotation. That is, when the combustion state deteriorates during the full lift injection control at the time of high load and low rotation, there is a high possibility that the cause of the deterioration is the fuel flow rate distribution in the spray. Therefore, if the injection control is switched to the partial lift injection control at this time, there is a very high possibility that the atomization degree of the fuel at the spray end portion is improved. That is, the fuel flow rate distribution in the spray is very likely to be a distribution suitable for forming a highly homogenous mixture. For this reason, according to 2nd Embodiment, deterioration of a combustion state can be improved more reliably.
　なお、第２実施形態において、噴射制御がフルリフト噴射制御からパーシャルリフト噴射制御に切り替えられる場合、切替前後の総燃料噴射量が同量に維持されることが好ましい。すなわち、切替後の総燃料噴射量（すなわち、パーシャルリフト噴射制御中の総燃料噴射量）が切替前の総燃料噴射量（すなわち、フルリフト噴射制御中の総燃料噴射量）と同量に維持されることが好ましい。 In addition, in 2nd Embodiment, when injection control is switched from full lift injection control to partial lift injection control, it is preferable that the total fuel injection amount before and after switching is maintained at the same amount. That is, the total fuel injection amount after switching (that is, the total fuel injection amount during partial lift injection control) is maintained at the same amount as the total fuel injection amount before the switching (that is, total fuel injection amount during full lift injection control). It is preferable.
＜第２実施形態の燃料噴射制御フロー＞
　第２実施形態の燃料噴射制御フローの一例が図１０に示されている。このフローは、所定時間が経過する毎に実行される。このフローが開始されると、始めに、ステップ３０において、目標燃料噴射量Ｑが決定される。次いで、ステップ３１において、トルク変動量ＣＴが所定量ＣＴｔｈよりも大きい（ＣＴ＞ＣＴｔｈ）か否かが判別される。ここで、ＣＴ＞ＣＴｔｈではないと判別されたときには、フローはそのまま終了する。この場合、現在の噴射制御が継続される。一方、ＣＴ＞ＣＴｔｈであると判別されたときには、ステップ３２において、フルリフトフラグＦｆがセットされている（Ｆｆ＝１）か否かが判別される。このフラグＦｆは、図７のフローのフルリフトフラグＦｆと同じフラグである。 <Fuel Injection Control Flow of Second Embodiment>
An example of the fuel injection control flow of the second embodiment is shown in FIG. This flow is executed every time a predetermined time elapses. When this flow is started, first, at step 30, the target fuel injection amount Q is determined. Next, at step 31, it is determined whether or not the torque fluctuation amount CT is larger than a predetermined amount CTth (CT> CTth). Here, when it is determined that CT> CTth is not satisfied, the flow ends as it is. In this case, the current injection control is continued. On the other hand, if it is determined that CT> CTth, it is determined in step 32 whether or not the full lift flag Ff is set (Ff = 1). This flag Ff is the same flag as the full lift flag Ff in the flow of FIG.
　ステップ３２において、Ｆｆ＝１であると判別されたとき（すなわち、フルリフト噴射制御が実行されているとき）には、ステップ３３において、機関回転数ＮＥが所定回転数ＮＥｔｈよりも小さく且つ機関負荷ＫＬが所定負荷ＫＬｔｈよりも大きい（ＮＥ＜ＮＥｔｈ且つＫＬ＞ＫＬｔｈ）か否かが判別される。 When it is determined in step 32 that Ff = 1 (that is, when full lift injection control is being executed), in step 33, the engine speed NE is smaller than the predetermined engine speed NEth and the engine load KL. Is greater than a predetermined load KLth (NE <NEth and KL> KLth).
　ここで、ＮＥ＜ＮＥｔｈ且つＫＬ＞ＫＬｔｈであると判別されたときには、ステップ３４において、パーシャルリフト量Ｌｐが決定される。次いで、ステップ３５において、ステップ３０で決定された目標燃料噴射量Ｑとステップ３４で決定されたパーシャルリフト量Ｌｐとに基づいて噴射回数Ｎｐが決定される。すなわち、ステップ３４で決定されたパーシャルリフト量Ｌｐのパーシャルリフト噴射によって、ステップ３０で決定された目標燃料噴射量Ｑの燃料を噴射するために必要なパーシャルリフト噴射の回数が決定される。次いで、ステップ３６において、噴射制御がフルリフト噴射制御からパーシャルリフト噴射制御に切り替えられ、フローが終了する。この場合、ステップ３６において噴射制御が切り替えられた後は、各気筒の各機関サイクルにおいて、ステップ３４で決定されたパーシャルリフト量Ｌｐでのパーシャルリフト噴射がステップ３５で決定された噴射回数Ｎｐだけ実行される。 Here, when it is determined that NE <NEth and KL> KLth, the partial lift amount Lp is determined in step 34. Next, at step 35, the number of injections Np is determined based on the target fuel injection amount Q determined at step 30 and the partial lift amount Lp determined at step 34. That is, the number of partial lift injections required to inject the fuel of the target fuel injection amount Q determined in step 30 is determined by the partial lift injection of the partial lift amount Lp determined in step 34. Next, in step 36, the injection control is switched from full lift injection control to partial lift injection control, and the flow ends. In this case, after the injection control is switched in step 36, the partial lift injection at the partial lift amount Lp determined in step 34 is executed for the number of injections Np determined in step 35 in each engine cycle of each cylinder. Is done.
　ステップ３３において、ＮＥ＜ＮＥｔｈ且つＫＬ＞ＫＬｔｈではないと判別されたときには、フローはそのまま終了する。この場合、現在の噴射制御（すなわち、フルリフト噴射制御）が継続される。 When it is determined in step 33 that NE <NEth and KL> KLth are not satisfied, the flow ends as it is. In this case, the current injection control (that is, full lift injection control) is continued.
　ステップ３２において、Ｆｆ＝１ではないと判別されたとき（すなわち、パーシャルリフト噴射制御が実行されている）ときには、ステップ３７において、噴射制御がパーシャルリフト噴射制御からフルリフト噴射制御に切り替えられ、フローが終了する。この場合、ステップ３７において噴射制御が切り替えられた後は、各気筒の各機関サイクルにおいて、ステップ３０で決定された目標燃料噴射量Ｑの燃料が噴射されるようにフルリフト噴射制御が実行される。 When it is determined in step 32 that Ff = 1 is not satisfied (that is, partial lift injection control is being executed), in step 37, the injection control is switched from partial lift injection control to full lift injection control, and the flow finish. In this case, after the injection control is switched in step 37, the full lift injection control is executed so that the fuel of the target fuel injection amount Q determined in step 30 is injected in each engine cycle of each cylinder.
　なお、上述したフローは、燃焼状態に応じてフルリフト噴射制御からパーシャル噴射制御への切替とパーシャルリフト噴射制御からフルリフト噴射制御への切替との両方を実施するものである。しかしながら、本発明は、燃焼状態に応じてこれら切替のいずれか一方のみを実施する場合にも適用可能である。 The flow described above performs both switching from full lift injection control to partial injection control and switching from partial lift injection control to full lift injection control in accordance with the combustion state. However, the present invention is also applicable to the case where only one of these switching is performed according to the combustion state.
＜本発明の適用範囲＞
　なお、上述では、燃料噴射弁が筒内上部の吸気弁側方の機関本体の部分に取り付けられている場合を例に本発明を説明したが、本発明は、燃料噴射弁が筒内に燃料を直接噴射するものである限り機関本体のいかなる部分に取り付けられている場合にも適用可能である。 <Scope of application of the present invention>
In the above description, the present invention has been described by taking as an example the case where the fuel injection valve is attached to the part of the engine body on the side of the intake valve at the upper part of the cylinder. The present invention can be applied to any part of the engine body as long as it directly injects fuel.
＜実施形態の総括＞
　以上説明から、本発明の実施形態は、広く捉えれば、筒内に燃料を直接噴射する燃料噴射弁１１を備え、該燃料噴射弁がスリット形状の噴孔３２を有し、フルリフト制御とパーシャルリフト制御とを選択的に実施可能な内燃機関の燃料噴射制御装置に関する。そして、この装置は、一方の噴射制御中に燃焼状態が所定の燃焼状態よりも悪化した場合（たとえば、トルク変動量が所定量よりも大きい場合）、切替前後の総燃料噴射量を同量に維持しつつ噴射制御を他方の噴射制御に切り替える制御部（電子制御装置）９０を具備するものであると言える。 <Summary of Embodiment>
From the above description, the embodiment of the present invention, when viewed broadly, includes the fuel injection valve 11 that directly injects fuel into the cylinder, the fuel injection valve has the slit-shaped injection hole 32, and provides full lift control and partial lift. The present invention relates to a fuel injection control device for an internal combustion engine capable of selectively performing control. When the combustion state is worse than the predetermined combustion state during one injection control (for example, when the torque fluctuation amount is larger than the predetermined amount), the total fuel injection amount before and after switching is set to the same amount. It can be said that the control part (electronic control apparatus) 90 which switches injection control to the other injection control is maintained.
　前記制御部は、たとえば、第１実施形態に関連して説明したように、フルリフト噴射制御中に燃焼状態が所定の燃焼状態よりも悪化した場合、切替前後の総燃料噴射量を同量に維持しつつ噴射制御をフルリフト噴射制御からパーシャルリフト噴射制御に切り替える。 For example, as described in relation to the first embodiment, the control unit maintains the same total fuel injection amount before and after switching when the combustion state is worse than a predetermined combustion state during the full lift injection control. The injection control is switched from full lift injection control to partial lift injection control.
　また、第２実施形態に関連して説明したように、前記制御部は、高負荷低回転時であってフルリフト噴射制御中に燃焼状態が前記所定の燃焼状態よりも悪化した場合に切替前後の総燃料噴射量を同量に維持しすつ噴射制御をフルリフト噴射制御からパーシャルリフト噴射制御に切り替えるようにしてもよい。 In addition, as described in relation to the second embodiment, the control unit performs before and after switching when the combustion state is worse than the predetermined combustion state during full lift injection control during high load and low rotation. The injection control that maintains the same total fuel injection amount may be switched from full lift injection control to partial lift injection control.
　また、第１実施形態に関連して説明したように、前記制御部は、パーシャルリフト噴射制御中に燃料状態が前記所定の燃焼状態であるときに噴射制御をパーシャルリフト噴射制御からフルリフト噴射制御に切り替えたとしても燃焼状態が前記所定の燃焼状態に維持される場合、切替前後の総燃料噴射量を同量に維持しつつ噴射制御をパーシャルリフト噴射制御からフルリフト噴射制御に切り替えるようにしてもよい。 Further, as described in relation to the first embodiment, the control unit changes the injection control from the partial lift injection control to the full lift injection control when the fuel state is the predetermined combustion state during the partial lift injection control. If the combustion state is maintained at the predetermined combustion state even after switching, the injection control may be switched from partial lift injection control to full lift injection control while maintaining the same total fuel injection amount before and after switching. .
　さらに、前記制御部は、たとえば、第１実施形態に関連して説明したように、パーシャルリフト噴射制御中に燃焼状態が前記所定の燃焼状態よりも悪化した場合、切替前後の総燃料噴射量を同量に維持しつつ噴射制御をパーシャルリフト噴射制御からフルリフト噴射制御に切り替える。 Further, for example, as described in relation to the first embodiment, the control unit determines the total fuel injection amount before and after switching when the combustion state is worse than the predetermined combustion state during the partial lift injection control. While maintaining the same amount, the injection control is switched from the partial lift injection control to the full lift injection control.

Claims (5)

  1. 　筒内に燃料を直接噴射する燃料噴射弁を備え、該燃料噴射弁がスリット形状の噴孔を有し、フルリフト噴射制御とパーシャルリフト噴射制御とを選択的に実施可能な内燃機関の燃料噴射制御装置において、一方の噴射制御中に燃焼状態が所定の燃焼状態よりも悪化した場合、切替前後の総燃料噴射量を同量に維持しつつ噴射制御を他方の噴射制御に切り替える制御部を具備する燃料噴射制御装置。 A fuel injection valve for an internal combustion engine having a fuel injection valve for directly injecting fuel into a cylinder, the fuel injection valve having a slit-shaped injection hole, and capable of selectively performing full lift injection control and partial lift injection control The apparatus includes a control unit that switches the injection control to the other injection control while maintaining the total fuel injection amount before and after switching when the combustion state becomes worse than a predetermined combustion state during one injection control. Fuel injection control device.
  2. 　前記制御部は、フルリフト噴射制御中に燃焼状態が所定の燃焼状態よりも悪化した場合、切替前後の総燃料噴射量を同量に維持しつつ噴射制御をフルリフト噴射制御からパーシャルリフト噴射制御に切り替える制御部を具備する燃料噴射制御装置。 The control unit switches the injection control from the full lift injection control to the partial lift injection control while maintaining the total fuel injection amount before and after switching when the combustion state becomes worse than the predetermined combustion state during the full lift injection control. A fuel injection control device comprising a control unit.
  3. 　前記制御部は、高負荷低回転時であってフルリフト噴射制御中に燃焼状態が前記所定の燃焼状態よりも悪化した場合に切替前後の総燃料噴射量を同量に維持しつつ噴射制御をフルリフト噴射制御からパーシャルリフト噴射制御に切り替える請求項１または２に記載の燃料噴射制御装置。 The control unit performs full lift injection control while maintaining the same total fuel injection amount before and after switching when the combustion state is worse than the predetermined combustion state during full lift injection control at high load and low speed. The fuel injection control device according to claim 1, wherein the fuel injection control device is switched from injection control to partial lift injection control.
  4. 　前記制御部は、パーシャルリフト噴射制御中に燃焼状態が前記所定の燃焼状態であるときに噴射制御をパーシャルリフト噴射制御からフルリフト噴射制御に切り替えたとしても燃焼状態が前記所定の燃焼状態に維持される場合、切替前後の総燃料噴射量を同量に維持しつつ噴射制御をパーシャルリフト噴射制御からフルリフト噴射制御に切り替える請求項１～３のいずれか１つに記載の燃料噴射制御装置。 The control unit maintains the combustion state in the predetermined combustion state even when the injection control is switched from the partial lift injection control to the full lift injection control when the combustion state is the predetermined combustion state during the partial lift injection control. The fuel injection control device according to any one of claims 1 to 3, wherein the injection control is switched from partial lift injection control to full lift injection control while maintaining the same total fuel injection amount before and after switching.
  5. 　前記制御部は、パーシャルリフト噴射制御中に燃焼状態が前記所定の燃焼状態よりも悪化した場合、切替前後の総燃料噴射量を同量に維持しつつ噴射制御をパーシャルリフト噴射制御からフルリフト噴射制御に切り替える請求項１～４のいずれか１つに記載の燃料噴射制御装置。 When the combustion state becomes worse than the predetermined combustion state during the partial lift injection control, the control unit changes the injection control from the partial lift injection control to the full lift injection control while maintaining the total fuel injection amount before and after switching. The fuel injection control device according to any one of claims 1 to 4, wherein
PCT/JP2013/064522 2013-05-24 2013-05-24 Fuel injection control device of internal combustion engine WO2014188597A1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002115629A (en) * 2000-10-12 2002-04-19 Nissan Motor Co Ltd Fuel injection control device for internal combustion engine
JP2009513856A (en) * 2003-06-30 2009-04-02 ダイムラー・アクチェンゲゼルシャフト Compression ignition internal combustion engine
WO2013073111A1 (en) * 2011-11-18 2013-05-23 株式会社デンソー Fuel injection control device for internal combustion engine
JP2013104329A (en) * 2011-11-11 2013-05-30 Toyota Motor Corp Fuel injection system of internal combustion engine

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002115629A (en) * 2000-10-12 2002-04-19 Nissan Motor Co Ltd Fuel injection control device for internal combustion engine
JP2009513856A (en) * 2003-06-30 2009-04-02 ダイムラー・アクチェンゲゼルシャフト Compression ignition internal combustion engine
JP2013104329A (en) * 2011-11-11 2013-05-30 Toyota Motor Corp Fuel injection system of internal combustion engine
WO2013073111A1 (en) * 2011-11-18 2013-05-23 株式会社デンソー Fuel injection control device for internal combustion engine

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