WO2015036825A1 - Control device of internal combustion engine - Google Patents

Control device of internal combustion engine Download PDF

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Publication number
WO2015036825A1
WO2015036825A1 PCT/IB2014/001730 IB2014001730W WO2015036825A1 WO 2015036825 A1 WO2015036825 A1 WO 2015036825A1 IB 2014001730 W IB2014001730 W IB 2014001730W WO 2015036825 A1 WO2015036825 A1 WO 2015036825A1
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WO
WIPO (PCT)
Prior art keywords
injection
fuel
period
split
amount
Prior art date
Application number
PCT/IB2014/001730
Other languages
French (fr)
Inventor
Teruaki Haibara
Original Assignee
Toyota Jidosha Kabushiki Kaisha
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Toyota Jidosha Kabushiki Kaisha filed Critical Toyota Jidosha Kabushiki Kaisha
Publication of WO2015036825A1 publication Critical patent/WO2015036825A1/en

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Classifications

    • 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
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/24—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means
    • F02D41/2406—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means using essentially read only memories
    • F02D41/2425—Particular ways of programming the data
    • F02D41/2429—Methods of calibrating or learning
    • F02D41/2451—Methods of calibrating or learning characterised by what is learned or calibrated
    • F02D41/2464—Characteristics of actuators
    • F02D41/2467—Characteristics of actuators for injectors
    • F02D41/247—Behaviour for small quantities
    • 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 control device of an internal combustion engine.
  • JP 2003-021024 A discloses that partial lift injection in which a needle valve is lifted for a smaller lift amount than a full lift amount is carried out for multiple times.
  • the present invention can achieve favorable atomization of fuel that is injected upon initial injection when split injection control for continuously carrying out partial lift injection, in which a needle valve starts being closed before a lift amount thereof reaches a maximum lift amount, for multiple times is carried out.
  • a control device for an internal combustion engine including a fuel injection valve that directly inject fuel in a cylinder
  • the control device includes: an electronic control unit configured to carry out split injection control, the split injection control being injection control that continuously carries put partial lift injection for multiple times, in which a needle valve of the fuel injection valve starts to close before a lift amount the needle valve reaches a maximum lift amount, and the electronic control unit being configured to set an injection period of initial injection longer than an injection period of each subsequent injection in the split injection control.
  • the injection period of the initial injection is extended.
  • a flow of the fuel in the sack is stabilized. Therefore, the fuel that is injected by the initial injection can favorably be atomized.
  • a control device for an internal combustion engine including a fuel injection valve that directly injects fuel into a cylinder
  • the control device includes: an electronic control unit configured to carry out split injection control, the split injection control being injection control that continuously carries out partial lift injection for multiple times, in which a needle valve of the fuel injection valve starts to close before " a lift amount of the needle valve reaches a maximum lift amount, the electronic control unit being configured to calculate a target injection amount for injected by the split injection control, the electronic control unit being configured to calculate a reference injection period that is a single injection period obtained by equally dividing the target injection amount by the number of split injection, and the electronic control unit being configured to set an injection period of initial injection longer than the reference injection period.
  • the injection period of the initial injection is extended.
  • the fuel that is injected by the initial injection can favorably be atomized.
  • the electronic control unit may set the injection period of the initial injection equal to or longer than a period in which the lift amount of the needle valve reaches a full lift amount. Accordingly, the initial injection becomes the full lift injection. Therefore, the fuel that is injected by the initial injection can further reliably and favorably be atomized.
  • the electronic control unit may calculate a minimum injection period of the each injection in the split injection control based on a sack remaining fuel amount when the each injection is initiated, and may set the injection period of the each injection equal to or longer than a corresponding minimum injection period in the split injection control respectively. Accordingly, the injection period of the each injection becomes the period that is equal to or longer than the minimum injection period that corresponds to the sack remaining fuel amount. Therefore, the fuel that is injected by the initial injection can further reliably and favorably be atomized.
  • the electronic control unit may estimate the sack remaining fuel amount based on an injection period of the last injection before the each injection, and an interval between a time at which the last injection is terminated and a time at which the injection is started. Accordingly, it is possible to accurately estimate the sack remaining fuel amount.
  • FIG. 1 shows an internal combustion engine to which a control apparatus of an embodiment of the present invention is applied
  • FIG. 2 shows a fuel injection valve of a first embodiment
  • FIG. 3A shows a change in a needle lift amount upon full lift injection
  • FIG. 3B shows a change in the needle lift amount upon partial lift injection
  • FIG. 4A, FIG. 4B, and FIG. 4C show an injection opening of the fuel injection valve of the first embodiment and a periphery thereof;
  • FIG. 5 A shows fuel spray upon the full lift injection
  • FIG. 5B shows fuel spray upon the partial lift injection
  • FIG. 6 A is a view that illustrates a spray angle upon the full lift injection
  • FIG. 6B is a view that illustrates the spray angle upon the partial lift injection
  • FIG. 7A shows a map of a target injection amount
  • FIG. 7B shows a map of a reference split number
  • FIG. 8 is a time chart that illustrates split injection control of the first embodiment
  • FIG. 9A, FIG, 9B, FIG. 9C, and FIG. 9D show states of a sack in the fuel injection valve upon the partial lift injection
  • FIG. 10A, FIG. 10B, FIG. IOC, FIG. 10D, and FIG. 10E show states of inside of the sack in the fuel injection valve upon the full lift injection;
  • FIG. 11 shows an example of a fuel injection control flow of the first embodiment
  • FIG. 12 is a time chart for illustrating split injection control of a second embodiment.
  • FIG. 13 shows an example of a fuel injection control flow of a third embodiment.
  • FIG. 1 shows a main body 10 of the internal combustion engine (hereinafter an "engine main body"), a fuel injection valve 11, a cylinder head 12, a cylinder block 13, an air intake valve 14, an exhaust valve 15, a spark plug 16, an in-cylinder pressure sensor 17, a combustion chamber 18, a piston 19, an electronic control unit (ECU) 90.
  • engine main body a main body 10 of the internal combustion engine
  • ECU electronice control unit
  • the fuel injection valve 11 is attached to a portion of the engine main body 10 on a side of the air intake valve 14 (for example, a portion of the cylinder head 12 or a portion of the cylinder block 13).
  • the fuel injection valve 11 and the spark plug 16 are electrically connected to the ECU 90.
  • the ECU 90 sends a control signal for controlling an operation of the fuel injection valve 11 to the fuel injection valve 11.
  • the ECU 90 sends a control signal for controlling an operation of the spark plug 16 to the spark plug 16.
  • the in-cylinder pressure sensor 17 is also electrically connected to the ECU 90.
  • the in-cylinder pressure sensor 17 outputs a signal that corresponds to an in-cylinder pressure (that is, a pressure inside the cylinder), and the signal is input to the ECU 90. Based on the signal, the ECU 90 calculates the in-cylinder pressure.
  • FIG. 2 shows a configuration of the fuel injection valve 11.
  • FIG. 2 shows a nozzle 30, a needle valve 31, a fuel injection opening 32 (hereinafter the "injection opening"), a fuel passage 33, a solenoid 34, a spring 35, a fuel intake port 36, an injection valve axis 37.
  • the injection valve axis 37 is an axis that extends in a longitudinal direction of the fuel injection valve 11.
  • the fuel injection valve 11 is a fuel injection valve of a so-called inner opening valve type. The fuel injection valve 11 can selectively carry out one of full lift injection or partial lift injection. As shown in FIG.
  • the full lift injection is fuel injection in which the needle valve 31 is lifted for a maximum lift amount (that is, maximum lift injection).
  • the partial lift injection is fuel injection in which the needle valve 31 is lifted for a smaller lift amount than the maximum lift amount (that is, sectional lift injection).
  • a needle lift amount can be controlled by controlling a time for energizing the fuel injection valve 11.
  • FIG. 3A shows a transition of the needle lift amount in a single full lift injection
  • FIG. 3B shows a transition of the needle lift amount in three-time partial lift injections.
  • FIG. 4A, FIG. 4B, and FIG. 4C show configurations of the injection opening 32 of the fuel injection valve ll of the first embodiment and a periphery thereof.
  • FIG. 4A shows a tip of the fuel injection valve 11 in a case where the tip of the fuel injection valve 11 is seen from the outside of the fuel injection valve 11 along the injection valve axis 37.
  • FIG. 4B shows a cross section that is taken along the line 4B-4B in FIG. 4A
  • FIG. 4C shows a cross section that is taken along the line 4C-4C in FIG. 4A.
  • FIGS. 4C show the nozzle 30, the needle valve 31, the injection opening 32,. the injection valve axis 37, a sack 38, a needle seat section 39 (hereinafter a "seat section"), a nozzle seat wall surface 40, a needle seat Wall surface 41, an inlet 44, and an outlet 45.
  • 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 in a completely closed state (that is, when the needle lift amount becomes zero).
  • the injection opening 32 has the inlet 44 and the outlet 45.
  • the inlet 44 is opened to the sack 38, and the fuel flows into the injection opening 32 via the inlet 44.
  • the outlet 45 is opened to the outside of the fuel injection valve 11, and the fuel is injected from the outlet 45.
  • the injection opening 32 of the fuel injection valve 11 of the first embodiment is an injection opening in a slit shape.
  • the injection opening 32 when the injection opening 32 is seen in a transverse section thereof, the injection opening 32 has a rectangular transverse section.
  • the transverse section of the injection opening refers to a cross section in a case where the injection opening is cut along a plane that is perpendicular to a center axis of the injection opening.
  • FIG. 4B when the injection opening 32 is seen in a cross-section 4B-4B, the injection opening 32 has a fan shape that spreads from the inlet 44 to the outlet 45.
  • a cross section of a flow passage of the injection opening 32 gradually increases from the inlet 44 to the outlet 45.
  • a flow passage area of the outlet 45 is larger than a flow passage area of the inlet 44.
  • the vertical cross section of the injection opening refers to a cross section thereof that is cut along a plane including the center axis of the injection opening and the injection valve axis 37.
  • Fuel spray (hereinafter "spray") 50 that is injected from the fuel injection valve 11 of the first embodiment is shown in FIG. 5A and FIG. 5B.
  • FIG. 5A and FIG. 5B show the spray in a case where the tip of the fuel injection valve 11 is seen from the outside of the fuel injection valve 11 along the injection valve axis 37.
  • FIG. 5A shows the spray upon the full lift injection
  • FIG. 5B shows the spray upon the partial lift injection.
  • a spray angle 52 upon the full lift injection is larger than the spray angle 52 upon the partial lift injection (see FIG. 6B).
  • a penetration force upon the full lift injection is larger than the penetration force upon the partial lift injection.
  • the spray angle 52 is an angle between outer edges 53 of the spray, and the penetration force is a force by which the spray advances in the cylinder.
  • an injection amount refers to a total amount of the fuel that is injected from the fuel injection valve in one engine cycle.
  • An engine operation state refers to an operation state of the internal combustion engine.
  • split injection refers to the injection by which the partial lift injection, in which the needle valve starts being closed before the lift amount thereof reaches the full lift amount, is continuously carried out for multiple times.
  • Split injection control refers to control for carrying out the split injection.
  • An injection period refers to a period in which the fuel injection valve is opened so that the fuel is injected from the fuel injection valve. The injection period is particularly a period in which the fuel injection valve is energized so that the fuel is injected from the fuel injection valve. .
  • an appropriate injection amount that corresponds to the engine operation state is calculated in advance by an experiment or the like. Then, as shown in FIG. 7A, the thus-calculated injection amount is stored in the ECU 90 as a target injection amount Qt in a form of a function map of an engine speed N and an engine load L. In addition, the appropriate number of split that corresponds to the engine operation state is calculated in advance by an experiment or the like. Then, as shown in FIG. 7B, the thus-calculated number of split is stored in the ECU 90 as a target split number Ndt in a form of a function map of the engine speed N and the engine load L.
  • the target injection amount Qt that corresponds to the engine speed N and the engine load L is obtained from the map in FIG. 7A, and the target split number Ndt that corresponds to the engine speed N and the engine load L is obtained from the map in FIG. 7B.
  • the injection period in which the fuel in the reference split injection amount is injected from the fuel injection valve for the each injection is calculated as a reference injection period.
  • a target injection period of the initial injection in the single split injection cycle is set to be longer than the reference injection period, and the target injection period of the second injection onward is set to be shorter than the reference injection period.
  • the target injection period of the initial injection is set to be longer than the target injection period of the second injection onward.
  • the fuel injection in the one engine cycle is carried out as shown in FIG. 8. More specifically, at a time TO, a control signal is switched from OFF to ON. Then, the initial injection is started, and the needle lift amount is gradually increased to reach the full lift amount. When the control signal is switched from ON to OFF at a time Tl, the needle lift amount is gradually reduced to become zero. That is, the initial injection is terminated. The injection carried out at this time is the full lift injection.
  • the control signal is switched from OFF to ON. Then, the second injection is started, and the needle lift amount is gradually increased. Thereafter, before the needle lift amount reaches the full lift amount, the control signal is switched from ON to OFF. Then, the needle lift amount is gradually reduced to become zero. That is, the second injection is terminated.
  • the injection carried out at this time is the partial lift injection.
  • the control signal is switched from OFF to ON, and the third injection is carried out.
  • the injection carried out at this time is also the partial lift injection.
  • the control signal is switched from OFF to ON, and the fourth injection is carried out.
  • the injection carried out at this time is also the partial lift injection.
  • the split injection in the one engine cycle is terminated after a lapse of a certain period.
  • the initial injection is terminated while the flow of the fuel in the sack remains to be unstable.
  • the fuel that is injected by the initial injection is not favorably atomized.
  • the fuel injection control of the first embodiment in the split injection control, the fuel is not present and only the gas is present in the sack before the initial injection is started, as shown in FIG. 10A. Then, when the control signal is switched from OFF to ON and the needle valve starts being lifted, as shown in FIG. 10B, the fuel starts flowing into the sack. The fuel that has flown into the sack is mixed with the gas in the sack, and is thereafter injected from the fuel injection valve.
  • the needle valve is further lifted, and the needle lift amount. reaches the full lift amount.
  • the sack is filled with the fuel. Since the flow of the fuel in the sack is stable at this time, the fuel that is injected at this time is favorably atomized.
  • the initial injection is carried out in a state that the flow of the fuel in the sack is stable.
  • the fuel that is injected by the initial injection can favorably be atomized.
  • an amount of the fuel that remains in the sack upon termination of the initial injection is larger than that in a case where the split injection control of the first embodiment is not adopted.
  • an interval between the initial injection and the second injection is extremely short.
  • the needle valve starts being lifted in the second injection
  • a relatively large amount of the fuel is present in the sack. Accordingly, the flow of the fuel in the sack is stabilized at this time. Therefore, even if the injection period of the second injection is set to be shorter than the injection period of the initial injection, the fuel that is injected by the second injection can favorably be atomized.
  • an interval between the second injection and the third injection is also extremely short.
  • a degree to extend the injection period in the initial injection and a degree to shorten the injection period in the second injection onward are preferably set to such a degree that the target injection amount of the fuel can be injected from the fuel injection valve by each of these injections.
  • the entire target injection amount Qt in. the one engine cycle is injected by the split injection.
  • the entire target injection amount Qt in the one engine cycle does not have to be injected by the split injection.
  • a part of the target injection amount Qt in the one engine cycle may be set to an injection amount for the normal full lift injection, and the remaining amount of the fuel may be injected as the injection amount for the split injection (that is, the partial lift injection).
  • the injection period of the initial injection is set longer until the injection period of the initial injection is shifted to the period in the full lift injection.
  • the injection period of the initial injection may be set longer only for a period in which the injection period of the initial injection is maintained for the partial lift injection.
  • the injection periods of the second injection onward in the partial lift injection are set to be equal to each other. However, these injection periods may be set to differ from each other.
  • step 10 the target injection amount Qt and the target split number Ndt, each of which corresponds to the engine speed N and the engine load L, are respectively obtained from the maps in FIG. 7A and FIG. 7B.
  • step 11 target split injection amounts Qdlt to Qd4t of the first injection to the fourth injection are calculated on the basis of the target injection amount Qt and the target split number Ndt that are obtained in step 10.
  • step 12 injection periods TAUdl to TAUd4 of the initial injection to the fourth injection are calculated on the basis of the target split injection amount Qdlt to Qd4t that are calculated in step 11.
  • step 13 the split injection is carried out in accordance with the injection periods TAUdl to TAUd4 that are calculated in step 12, and the flow is then terminated.
  • the target injection amount Qt that corresponds to the engine speed N and the engine load L is obtained from the map in FIG. 7A, and the target split number Ndt that corresponds to the engine speed N and the engine load L is obtained from the map in FIG. 7B.
  • the injection period in which the fuel in the reference split injection amount is injected from the fuel injection valve for the each injection is calculated as the reference injection period.
  • the target injection period of the initial injection is set to be longer than the reference injection period, and the target injection period of the second partial lift injection is set to be shorter than the reference injection period.
  • the target injection period of the third injection onward is set to be equal to the reference injection period. In other words, the target injection period of the initial injection is set to be longer than the target injection period of the second injection onward.
  • the split injection control is carried out in accordance with the injection period that is set after a lapse of a certain period.
  • the fuel injection in the one engine cycle is carried out as shown in FIG. 12. More specifically, at the time TO, the control signal is switched from OFF to ON.
  • the initial injection is started, and the needle lift amount is gradually increased to reach the full lift amount.
  • the control signal is switched from ON to OFF at the time Tl, the needle lift amount is gradually reduced to become zero. That is, the initial injection is terminated.
  • the injection carried out at this time is the full lift injection.
  • the control signal is switched from OFF to ON. Then, the second injection is started, and the needle lift amount is gradually increased. Thereafter, before the needle lift amount reaches the full lift amount, the control signal is switched from ON to OFF. Then, the needle lift amount is gradually reduced to become zero. That is, the second injection is terminated.
  • the injection carried out at this time is the partial lift injection.
  • the control signal is switched from OFF to ON, and the third injection is carried out.
  • the injection carried out at this time is also the partial lift injection.
  • the control signal is switched from OFF to ON, and the fourth injection is carried out.
  • the injection carried out at this time is also the partial lift injection.
  • the injection period at this time is shorter than the injection period of the initial injection but longer than the injection period of the second injection.
  • the split injection in the one engine cycle is terminated after a lapse of a certain period.
  • the fuel that is injected by the initial injection can favorably be atomized due to the same reason as the reason that has been described in relation to the first embodiment.
  • the target injection amount Qt which corresponds to the engine speed N and the engine load L
  • the target split number Ndt which corresponds to the engine speed N and the engine load L
  • the injection period in which the fuel in the reference split injection amount is injected from the fuel injection valve for the each injection is calculated as the reference injection period.
  • a minimum injection period of the each injection in the split injection control is set on the basis of a remaining fuel amount in the sack upon initiation of the each injection.
  • the target injection period of the initial injection is set to be longer than the reference injection period, and the target injection period of the second injection onward is set to be shorter than the reference injection period.
  • the target injection period that is set as described above is set as the target injection period.
  • the target injection period of the injection is set as the minimum injection period. Then, the split injection control is carried out in accordance with the injection period that is set after a lapse of a certain period.
  • a degree of atomization of the fuel, which is injected by the each injection depends on the remaining amount of the fuel in the sack (hereinafter the "remaining fuel amount") upon the initiation of the each injection. That is, as the remaining fuel amount is large, the degree of atomization of the fuel, which is injected by the each injection, is increased.
  • the injection period of the each injection is set at least equal to the minimum injection period, which is set in accordance with the remaining fuel amount. Therefore, the fuel that is injected by the each injection can reliably and favorably be atomized.
  • the remaining fuel amount is estimated on the basis of the injection period of the last injection before the each injection, and an interval between the time at which the last injection is terminated and a time at which the present injection is started.
  • the last injection before the each injection refers to the last injection in the previous split injection for the initial injection.
  • the last injection before the each injection refers to the initial injection.
  • the last injection before the each injection refers to the second injection.
  • the last injection before the each injection refers to the third injection.
  • the remaining fuel amount is large as the injection period of the last injection before the each injection is long.
  • the remaining fuel amount is small as the above interval is long. Accordingly, it is possible to precisely estimate the remaining fuel amount.
  • step 20 the target injection amount Qt and the target split number Ndt, each of which corresponds to the engine speed N and the engine load L, are respectively obtained from the maps in FIG. 7A and FIG. 7B.
  • step 21 the target split injection amounts Qdlt to Qd4t of the initial injection to the fourth injection are calculated on the basis of the target injection amount Qt and the target split number Ndt that are obtained in step 20.
  • step 22 the injection periods TAUdl to TAUd4 of the initial injection to the fourth injection are calculated on the basis of the target split injection amount Qdlt to Qd4t that are calculated in step 21.
  • step 23 it is determined whether the injection period TAUdl of the initial injection, which is calculated in step 22, is shorter than a corresponding minimum injection period MINI (TAUdl ⁇ MINI).
  • TAUdl ⁇ MINI a minimum injection period
  • the flow proceeds to step 24, the minimum injection period MINI is input as the injection period TAUdl of the initial injection, and the flow proceeds to step 26.
  • the flow proceeds to step 25, the injection period TAUdl that is calculated in step 22 is input as the injection period TAUdl in the initial injection, and the flow proceeds, to step 26.
  • step 26 it is determined whether the injection period TAUd2 of the second, injection, which is calculated in . step 22, is shorter than a corresponding minimum injection period MIN2 (TAUd2. ⁇ MIN2).
  • TAUd2. ⁇ MIN2 a minimum injection period
  • the flow proceeds to step 27, the minimum injection period MIN2 is input as the injection period TAUd2 of the second injection, and the flow proceeds to step 29.
  • the flow proceeds to step 28, the injection period TAUd2 that is calculated in the step 22 is input as the injection period TAUd2 of the second injection, and the flow proceeds to step 29.
  • step 29 it is determined whether the injection period TAUd3 of the third injection, which is calculated in step 22, is shorter than a corresponding minimum injection period MIN3 (TAUd3 ⁇ MIN3).
  • TAUd3 ⁇ MIN3 a minimum injection period
  • the flow proceeds to step 30, the minimum injection period MIN3 is input as the injection period TAUd3 of the third injection, and the flow proceeds to step 32.
  • the flow proceeds to step 31, the injection period TAUd3 that is calculated in step 22 is input as the injection period TAUd3 of the third injection, and the flow proceeds to step 32.
  • step 32 it is determined whether the injection period TAUd4 of the fourth injection, which is calculated in step 22, is shorter than a corresponding minimum injection period MIN4 (TAUd4 ⁇ MIN4).
  • TAUd4 ⁇ MIN4 a minimum injection period
  • the flow proceeds to step 33, the minimum injection period MIN4 is input as the injection period TAUd4 of the fourth injection, and the flow proceeds to step 35.
  • the flow proceeds to step 34, the injection period TAUd4 that is calculated in step 22 is input as the injection period TAUd4 of the fourth injection, and the flow proceeds to step 35.
  • step 35 the split injection is carried out in accordance with the injection periods TAUdl to TAUd4, and the flow is terminated.
  • the control apparatus of each of the above embodiments can be said as a control apparatus applied to the internal combustion engine that includes the fuel injection valve (for example, the fuel injection valve 11) for directly injecting the fuel into the cylinder in a broader sense.
  • the control apparatus of each of the above embodiments includes a control section (for example, the ECU 90) for executing the split injection control that continuously carries out the partial lift injection, in which " the needle valve 31 starts being closed before the lift amount thereof reaches the maximum lift amount, for multiple times.
  • the control section sets the injection period TAUdl of the initial injection to be longer than the injection periods TAUd2 to TAUd4 of the second injection onward.
  • control apparatus of each of the above embodiments can be said as a control apparatus applied to the internal combustion engine that includes the fuel injection valve (for example, the fuel injection valve 11) for directly injecting the fuel into the cylinder.
  • the control apparatus of each of the above embodiments includes the control section (for example, the ECU 90) for executing the split injection control that continuously carries out the partial lift injection, in which the needle valve 31 starts being closed before the lift amount thereof reaches the maximum lift amount, for multiple times.
  • the control section sets the injection period TAUdl of the initial injection to be longer than the reference injection period that is the injection period of the one injection when the target injection amount injected by the split injection control is equally divided by the target split number for injection.

Abstract

A control device for an internal combustion engine including a fuel injection valve that directly injects fuel into a cylinder, the control device includes an electronic control unit configured to carry out split injection control, the split injection control being injection control that continuously carries out partial lift injection for multiple times, in which a needle valve of the fuel injection valve starts to close before a lift amount of the needle valve reaches a maximum lift amount, and the electronic control unit being configured to set an injection period of initial injection longer than an injection period of subsequent injection in the split injection control.

Description

CONTROL DEVICE OF INTERNAL COMBUSTION ENGINE
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] The present invention relates to a control device of an internal combustion engine.
2. Description of Related Art
[0002] Japanese Patent Application Publication No. 2003-021024 (JP 2003-021024 A) discloses that partial lift injection in which a needle valve is lifted for a smaller lift amount than a full lift amount is carried out for multiple times.
SUMMARY OF THE INVENTION
[0003] In a case where partial lift injection is carried out for multiple times, an amount of fuel that remains in a sack is extremely low at the time when the initial injection is started. Thus, a flow of the fuel in the sack is unstable when the initial injection is carried out, and the fuel is not favorably atomized.
[0004] The present invention can achieve favorable atomization of fuel that is injected upon initial injection when split injection control for continuously carrying out partial lift injection, in which a needle valve starts being closed before a lift amount thereof reaches a maximum lift amount, for multiple times is carried out.
[0005] A control device for an internal combustion engine according to a first aspect of the present invention including a fuel injection valve that directly inject fuel in a cylinder, the control device includes: an electronic control unit configured to carry out split injection control, the split injection control being injection control that continuously carries put partial lift injection for multiple times, in which a needle valve of the fuel injection valve starts to close before a lift amount the needle valve reaches a maximum lift amount, and the electronic control unit being configured to set an injection period of initial injection longer than an injection period of each subsequent injection in the split injection control.
[0006] According to the first aspect of the present invention, the injection period of the initial injection is extended. Thus, even when there is no fuel remaining in a sack of the fuel injection valve upon initiation of initial injection, a flow of the fuel in the sack is stabilized. Therefore, the fuel that is injected by the initial injection can favorably be atomized.
[0007] A control device for an internal combustion engine according to a second aspect of the present invention including a fuel injection valve that directly injects fuel into a cylinder, the control device includes: an electronic control unit configured to carry out split injection control, the split injection control being injection control that continuously carries out partial lift injection for multiple times, in which a needle valve of the fuel injection valve starts to close before" a lift amount of the needle valve reaches a maximum lift amount, the electronic control unit being configured to calculate a target injection amount for injected by the split injection control, the electronic control unit being configured to calculate a reference injection period that is a single injection period obtained by equally dividing the target injection amount by the number of split injection, and the electronic control unit being configured to set an injection period of initial injection longer than the reference injection period.
[0008] According to the second aspect of the present invention, the injection period of the initial injection is extended. Thus, even when an amount of the fuel that remains in a sack of the fuel injection valve is extremely low upon initiation of the initial injection, a flow of the fuel in the sack is stabilized. Therefore, the fuel that is injected by the initial injection can favorably be atomized.
[0009] In the split injection control, the electronic control unit (control section) may set the injection period of the initial injection equal to or longer than a period in which the lift amount of the needle valve reaches a full lift amount. Accordingly, the initial injection becomes the full lift injection. Therefore, the fuel that is injected by the initial injection can further reliably and favorably be atomized. [0010] In addition, the electronic control unit (control section) may calculate a minimum injection period of the each injection in the split injection control based on a sack remaining fuel amount when the each injection is initiated, and may set the injection period of the each injection equal to or longer than a corresponding minimum injection period in the split injection control respectively. Accordingly, the injection period of the each injection becomes the period that is equal to or longer than the minimum injection period that corresponds to the sack remaining fuel amount. Therefore, the fuel that is injected by the initial injection can further reliably and favorably be atomized.
[0011] Furthermore, the electronic control unit (control section) may estimate the sack remaining fuel amount based on an injection period of the last injection before the each injection, and an interval between a time at which the last injection is terminated and a time at which the injection is started. Accordingly, it is possible to accurately estimate the sack remaining fuel amount.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Features, advantages, and technical and industrial significance of exemplary embodiments of the invention will be described below with reference to^ the accompanying drawings, in which like numerals denote like elements, and wherein:
FIG. 1 shows an internal combustion engine to which a control apparatus of an embodiment of the present invention is applied;
FIG. 2 shows a fuel injection valve of a first embodiment;
FIG. 3A shows a change in a needle lift amount upon full lift injection, and FIG. 3B shows a change in the needle lift amount upon partial lift injection;
FIG. 4A, FIG. 4B, and FIG. 4C show an injection opening of the fuel injection valve of the first embodiment and a periphery thereof;
FIG. 5 A shows fuel spray upon the full lift injection, and FIG. 5B shows fuel spray upon the partial lift injection;
FIG. 6 A is a view that illustrates a spray angle upon the full lift injection, and FIG. 6B is a view that illustrates the spray angle upon the partial lift injection; FIG. 7A shows a map of a target injection amount, and FIG. 7B shows a map of a reference split number;
FIG. 8 is a time chart that illustrates split injection control of the first embodiment;
FIG. 9A, FIG, 9B, FIG. 9C, and FIG. 9D show states of a sack in the fuel injection valve upon the partial lift injection;
FIG. 10A, FIG. 10B, FIG. IOC, FIG. 10D, and FIG. 10E show states of inside of the sack in the fuel injection valve upon the full lift injection;
FIG. 11 shows an example of a fuel injection control flow of the first embodiment;
FIG. 12 is a time chart for illustrating split injection control of a second embodiment; and
FIG. 13 shows an example of a fuel injection control flow of a third embodiment.
DETAILED DESCRIPTION OF EMBODIMENTS
[0013] <First Embodiment A description will hereinafter be made on an embodiment of the present invention with reference to the drawings. An internal combustion engine to which a fuel injection control apparatus of the present invention is applied is shown in FIG. 1. FIG. 1 shows a main body 10 of the internal combustion engine (hereinafter an "engine main body"), a fuel injection valve 11, a cylinder head 12, a cylinder block 13, an air intake valve 14, an exhaust valve 15, a spark plug 16, an in-cylinder pressure sensor 17, a combustion chamber 18, a piston 19, an electronic control unit (ECU) 90.
[0014] In an upper portion of a cylinder (that is, the combustion chamber 18), the fuel injection valve 11 is attached to a portion of the engine main body 10 on a side of the air intake valve 14 (for example, a portion of the cylinder head 12 or a portion of the cylinder block 13).
[0015] The fuel injection valve 11 and the spark plug 16 are electrically connected to the ECU 90. The ECU 90 sends a control signal for controlling an operation of the fuel injection valve 11 to the fuel injection valve 11. In addition, the ECU 90 sends a control signal for controlling an operation of the spark plug 16 to the spark plug 16.
[0016] The in-cylinder pressure sensor 17 is also electrically connected to the ECU 90. The in-cylinder pressure sensor 17 outputs a signal that corresponds to an in-cylinder pressure (that is, a pressure inside the cylinder), and the signal is input to the ECU 90. Based on the signal, the ECU 90 calculates the in-cylinder pressure.
[0017] Configuration of Fuel Injection Valve of First Embodiment FIG. 2 shows a configuration of the fuel injection valve 11. FIG. 2 shows a nozzle 30, a needle valve 31, a fuel injection opening 32 (hereinafter the "injection opening"), a fuel passage 33, a solenoid 34, a spring 35, a fuel intake port 36, an injection valve axis 37. The injection valve axis 37 is an axis that extends in a longitudinal direction of the fuel injection valve 11. The fuel injection valve 11 is a fuel injection valve of a so-called inner opening valve type. The fuel injection valve 11 can selectively carry out one of full lift injection or partial lift injection. As shown in FIG. 3A, the full lift injection is fuel injection in which the needle valve 31 is lifted for a maximum lift amount (that is, maximum lift injection). Meanwhile, as shown in FIG. 3B, the partial lift injection is fuel injection in which the needle valve 31 is lifted for a smaller lift amount than the maximum lift amount (that is, sectional lift injection). A needle lift amount can be controlled by controlling a time for energizing the fuel injection valve 11. Here, FIG. 3A shows a transition of the needle lift amount in a single full lift injection, and FIG. 3B shows a transition of the needle lift amount in three-time partial lift injections.
[0018] Configurations of Injection Opening and Peripheries Thereof in First Embodiment FIG. 4A, FIG. 4B, and FIG. 4C show configurations of the injection opening 32 of the fuel injection valve ll of the first embodiment and a periphery thereof. FIG. 4A shows a tip of the fuel injection valve 11 in a case where the tip of the fuel injection valve 11 is seen from the outside of the fuel injection valve 11 along the injection valve axis 37. FIG. 4B shows a cross section that is taken along the line 4B-4B in FIG. 4A, and FIG. 4C shows a cross section that is taken along the line 4C-4C in FIG. 4A. FIG. 4A, FIG. 4B, and FIG. 4C show the nozzle 30, the needle valve 31, the injection opening 32,. the injection valve axis 37, a sack 38, a needle seat section 39 (hereinafter a "seat section"), a nozzle seat wall surface 40, a needle seat Wall surface 41, an inlet 44, and an outlet 45.
[0019] 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 in a completely closed state (that is, when the needle lift amount becomes zero).
[0020] Configuration of Injection Opening> The injection opening 32 has the inlet 44 and the outlet 45. The inlet 44 is opened to the sack 38, and the fuel flows into the injection opening 32 via the inlet 44. The outlet 45 is opened to the outside of the fuel injection valve 11, and the fuel is injected from the outlet 45.
[0021] <Shape of Injection Opening> The injection opening 32 of the fuel injection valve 11 of the first embodiment is an injection opening in a slit shape. In other words, as shown in FIG. 4A, when the injection opening 32 is seen in a transverse section thereof, the injection opening 32 has a rectangular transverse section. Here, the transverse section of the injection opening refers to a cross section in a case where the injection opening is cut along a plane that is perpendicular to a center axis of the injection opening. In addition, as shown in FIG. 4B, when the injection opening 32 is seen in a cross-section 4B-4B, the injection opening 32 has a fan shape that spreads from the inlet 44 to the outlet 45. Thus, a cross section of a flow passage of the injection opening 32 gradually increases from the inlet 44 to the outlet 45. Needless to say, a flow passage area of the outlet 45 is larger than a flow passage area of the inlet 44. In addition, as shown in FIG. 4C, when the injection opening 32 is seen in a vertical cross section thereof, the injection opening 32 has a substantially rectangular shape. Here, the vertical cross section of the injection opening refers to a cross section thereof that is cut along a plane including the center axis of the injection opening and the injection valve axis 37.
[0022] distribution of Fuel Flow Volume in Spray> Fuel spray (hereinafter "spray") 50 that is injected from the fuel injection valve 11 of the first embodiment is shown in FIG. 5A and FIG. 5B. FIG. 5A and FIG. 5B show the spray in a case where the tip of the fuel injection valve 11 is seen from the outside of the fuel injection valve 11 along the injection valve axis 37. FIG. 5A shows the spray upon the full lift injection, and FIG. 5B shows the spray upon the partial lift injection.
[0023] <Spray Angle and Penetration Force of First Embodiment As shown in FIG. 6A and FIG. 6B, in the fuel injection valve 11 of the first embodiment, a spray angle 52 upon the full lift injection (see FIG. 6A) is larger than the spray angle 52 upon the partial lift injection (see FIG. 6B). In addition, a penetration force upon the full lift injection is larger than the penetration force upon the partial lift injection. Here, the spray angle 52 is an angle between outer edges 53 of the spray, and the penetration force is a force by which the spray advances in the cylinder.
[0024] <Fuel Injection Control of First Embodiment A description will be made on fuel injection control of the first embodiment. In the following description, an injection amount refers to a total amount of the fuel that is injected from the fuel injection valve in one engine cycle. An engine operation state refers to an operation state of the internal combustion engine. Here, split injection refers to the injection by which the partial lift injection, in which the needle valve starts being closed before the lift amount thereof reaches the full lift amount, is continuously carried out for multiple times. Split injection control refers to control for carrying out the split injection. An injection period refers to a period in which the fuel injection valve is opened so that the fuel is injected from the fuel injection valve. The injection period is particularly a period in which the fuel injection valve is energized so that the fuel is injected from the fuel injection valve. .
[0025] In the first embodiment, an appropriate injection amount that corresponds to the engine operation state is calculated in advance by an experiment or the like. Then, as shown in FIG. 7A, the thus-calculated injection amount is stored in the ECU 90 as a target injection amount Qt in a form of a function map of an engine speed N and an engine load L. In addition, the appropriate number of split that corresponds to the engine operation state is calculated in advance by an experiment or the like. Then, as shown in FIG. 7B, the thus-calculated number of split is stored in the ECU 90 as a target split number Ndt in a form of a function map of the engine speed N and the engine load L.
[0026] During an operation of the engine, the target injection amount Qt that corresponds to the engine speed N and the engine load L is obtained from the map in FIG. 7A, and the target split number Ndt that corresponds to the engine speed N and the engine load L is obtained from the map in FIG. 7B. Then, the target injection amount Qt that is obtained after a lapse of a certain period is divided by the target split number Ndt to obtain an amount (= Qt/Ndt), which is set as an injection amount for a single injection in a single split injection cycle (hereinafter a "reference split injection amount"). Furthermore, the injection period in which the fuel in the reference split injection amount is injected from the fuel injection valve for the each injection is calculated as a reference injection period.
[0027] Thereafter, a target injection period of the initial injection in the single split injection cycle is set to be longer than the reference injection period, and the target injection period of the second injection onward is set to be shorter than the reference injection period. In other words, the target injection period of the initial injection is set to be longer than the target injection period of the second injection onward. Then, the split injection control is carried out in accordance with the injection period that is set after a lapse of a certain period.
[0028] According to what has been described above, the fuel injection in the one engine cycle is carried out as shown in FIG. 8. More specifically, at a time TO, a control signal is switched from OFF to ON. Then, the initial injection is started, and the needle lift amount is gradually increased to reach the full lift amount. When the control signal is switched from ON to OFF at a time Tl, the needle lift amount is gradually reduced to become zero. That is, the initial injection is terminated. The injection carried out at this time is the full lift injection.
[0029] Next, at a time T2, the control signal is switched from OFF to ON. Then, the second injection is started, and the needle lift amount is gradually increased. Thereafter, before the needle lift amount reaches the full lift amount, the control signal is switched from ON to OFF. Then, the needle lift amount is gradually reduced to become zero. That is, the second injection is terminated. The injection carried out at this time is the partial lift injection.
[0030] Next, at a time T3, the control signal is switched from OFF to ON, and the third injection is carried out. The injection carried out at this time is also the partial lift injection. Then, at a time T4, the control signal is switched from OFF to ON, and the fourth injection is carried out. The injection carried out at this time is also the partial lift injection. The split injection in the one engine cycle is terminated after a lapse of a certain period.
[0031] <Advantages of Fuel Injection Control of First Embodiment According to the fuel injection control of the first embodiment, in the split injection control, the fuel that is injected by the initial injection can favorably be atomized. A reason for the favorable atomization will be described below.
[0032] In the split injection control, as shown in FIG. 9A, a remaining amount of the fuel is extremely low and a large amount of gas is present in the sack before the initial injection is started. Then, when the control signal is switched from OFF to ON and the needle valve starts being lifted, the fuel starts flowing into the sack as shown in FIG. 9B. Then, the fuel that has flown into the sack is mixed with the gas in the sack, and is injected from the fuel injection valve. Since a flow of the fuel in the sack is unstable at this time, the fuel that is injected at this time is not favorably atomized.
[0033] Here, when the control signal is switched from ON to OFF, the needle valve is lowered as shown in FIG. 9C. Then, as shown in FIG. 9D, the needle valve is seated on the needle seat section, and the initial injection is terminated.
[0034] In this case, the initial injection is terminated while the flow of the fuel in the sack remains to be unstable. Thus, the fuel that is injected by the initial injection is not favorably atomized.
[0035] On the other hand, according to the fuel injection control of the first embodiment, in the split injection control, the fuel is not present and only the gas is present in the sack before the initial injection is started, as shown in FIG. 10A. Then, when the control signal is switched from OFF to ON and the needle valve starts being lifted, as shown in FIG. 10B, the fuel starts flowing into the sack. The fuel that has flown into the sack is mixed with the gas in the sack, and is thereafter injected from the fuel injection valve.
[0036] Then, according to the fuel injection control of the first embodiment, the needle valve is further lifted, and the needle lift amount. reaches the full lift amount. At this time, as shown in FIG. IOC, the sack is filled with the fuel. Since the flow of the fuel in the sack is stable at this time, the fuel that is injected at this time is favorably atomized.
[0037] Then, when the control signal is switched from ON to OFF, as shown in FIG. 10D, the needle valve is lowered. Thereafter, as shown in FIG. 10E, the needle valve is seated on the needle seat section, and the initial injection is terminated.
[0038] In this case, the initial injection is carried out in a state that the flow of the fuel in the sack is stable. Thus, the fuel that is injected by the initial injection can favorably be atomized.
[0039] When the split injection control of the first embodiment is carried out, an amount of the fuel that remains in the sack upon termination of the initial injection is larger than that in a case where the split injection control of the first embodiment is not adopted. In addition, an interval between the initial injection and the second injection is extremely short. Thus, when the needle valve starts being lifted in the second injection, a relatively large amount of the fuel is present in the sack. Accordingly, the flow of the fuel in the sack is stabilized at this time. Therefore, even if the injection period of the second injection is set to be shorter than the injection period of the initial injection, the fuel that is injected by the second injection can favorably be atomized.
[0040] Furthermore, an interval between the second injection and the third injection is also extremely short. Thus, when the needle valve starts being lifted in the third injection, a relatively large amount of the fuel is present in the sack. Accordingly, the flow of the fuel in the sack is stabilized at this time. Therefore, the fuel that is injected by the third injection is favorably atomized. [0041] Application Range of First Embodiment> A degree to extend the injection period in the initial injection and a degree to shorten the injection period in the second injection onward are preferably set to such a degree that the target injection amount of the fuel can be injected from the fuel injection valve by each of these injections.
[0042] In the first embodiment, the entire target injection amount Qt in. the one engine cycle is injected by the split injection. However, the entire target injection amount Qt in the one engine cycle does not have to be injected by the split injection. For example, a part of the target injection amount Qt in the one engine cycle may be set to an injection amount for the normal full lift injection, and the remaining amount of the fuel may be injected as the injection amount for the split injection (that is, the partial lift injection).
[0043] In the first embodiment, the injection period of the initial injection is set longer until the injection period of the initial injection is shifted to the period in the full lift injection. However, the injection period of the initial injection may be set longer only for a period in which the injection period of the initial injection is maintained for the partial lift injection.
[0044] In the first embodiment, the injection periods of the second injection onward in the partial lift injection are set to be equal to each other. However, these injection periods may be set to differ from each other.
[0045] <Fuel Injection Control Flow of First Embodiment A description will be made on a fuel injection control flow of the first embodiment. An example of the flow is shown in FIG. 11. Once the flow in FIG. 11 is initiated, first in step 10, the target injection amount Qt and the target split number Ndt, each of which corresponds to the engine speed N and the engine load L, are respectively obtained from the maps in FIG. 7A and FIG. 7B. Next, in step 11, target split injection amounts Qdlt to Qd4t of the first injection to the fourth injection are calculated on the basis of the target injection amount Qt and the target split number Ndt that are obtained in step 10. Next, in step 12, injection periods TAUdl to TAUd4 of the initial injection to the fourth injection are calculated on the basis of the target split injection amount Qdlt to Qd4t that are calculated in step 11. Next, in step 13, the split injection is carried out in accordance with the injection periods TAUdl to TAUd4 that are calculated in step 12, and the flow is then terminated.
[0046] <Fuel Injection Control of Second Embodiment A description will be made on fuel injection control of a second embodiment. For some embodiments described below, a configuration and control of the each embodiment, which will not be described, are the same as a configuration and control of another embodiment described in this specification or correspond to a configuration and control that are naturally derived from a configuration and control of another embodiment in view of the configuration and control of the each embodiment.
[0047] In the second embodiment, during the engine operation, the target injection amount Qt that corresponds to the engine speed N and the engine load L is obtained from the map in FIG. 7A, and the target split number Ndt that corresponds to the engine speed N and the engine load L is obtained from the map in FIG. 7B. Then, the target injection amount Qt that is obtained after a lapse of a certain period is divided by the target split number Ndt to obtain an amount (= Qt/Ndt), which is set as the injection amount for the single injection in the single split injection cycle (hereinafter the "reference split injection amount"). Furthermore, the injection period in which the fuel in the reference split injection amount is injected from the fuel injection valve for the each injection is calculated as the reference injection period.
[0048] Thereafter, the target injection period of the initial injection is set to be longer than the reference injection period, and the target injection period of the second partial lift injection is set to be shorter than the reference injection period. The target injection period of the third injection onward is set to be equal to the reference injection period. In other words, the target injection period of the initial injection is set to be longer than the target injection period of the second injection onward. Then, the split injection control is carried out in accordance with the injection period that is set after a lapse of a certain period. [0049] According to what has been described above, the fuel injection in the one engine cycle is carried out as shown in FIG. 12. More specifically, at the time TO, the control signal is switched from OFF to ON. Then, the initial injection is started, and the needle lift amount is gradually increased to reach the full lift amount. When the control signal is switched from ON to OFF at the time Tl, the needle lift amount is gradually reduced to become zero. That is, the initial injection is terminated. The injection carried out at this time is the full lift injection.
[0050] Next, at the time T2, the control signal is switched from OFF to ON. Then, the second injection is started, and the needle lift amount is gradually increased. Thereafter, before the needle lift amount reaches the full lift amount, the control signal is switched from ON to OFF. Then, the needle lift amount is gradually reduced to become zero. That is, the second injection is terminated. The injection carried out at this time is the partial lift injection.
[0051] Next, at the time T3, the control signal is switched from OFF to ON, and the third injection is carried out. The injection carried out at this time is also the partial lift injection. Then, at the time T4, the control signal is switched from OFF to ON, and the fourth injection is carried out. The injection carried out at this time is also the partial lift injection. The injection period at this time is shorter than the injection period of the initial injection but longer than the injection period of the second injection. The split injection in the one engine cycle is terminated after a lapse of a certain period.
[0052] <Advantages of Fuel Injection Control of Second Embodiment According to the fuel injection control of the second embodiment, the fuel that is injected by the initial injection can favorably be atomized due to the same reason as the reason that has been described in relation to the first embodiment.
[0053] <Fuel Injection Control of Third Embodiment In a third embodiment, during the- engine operation, the target injection amount Qt, which corresponds to the engine speed N and the engine load L, is obtained from the map in FIG. 7A, and the target split number Ndt, which corresponds to the engine speed N and the engine load L, is obtained from the map in FIG. 7B. Then, the target injection amount Qt that is obtained after a lapse of a certain period is divided by the target split number Ndt to obtain an amount (= Qt/Ndt), which is set as the injection amount for the single injection in the single split injection cycle (hereinafter the "reference split injection amount"). Furthermore, the injection period in which the fuel in the reference split injection amount is injected from the fuel injection valve for the each injection is calculated as the reference injection period.
[0054] Meanwhile, in the third embodiment, a minimum injection period of the each injection in the split injection control is set on the basis of a remaining fuel amount in the sack upon initiation of the each injection.
[0055] Thereafter, the target injection period of the initial injection is set to be longer than the reference injection period, and the target injection period of the second injection onward is set to be shorter than the reference injection period. When the injection period of the each injection is at least equal to the respectively corresponding minimum injection period, the target injection period that is set as described above is set as the target injection period. On the other hand, when the injection period of any injection is shorter than the corresponding minimum injection period, the target injection period of the injection is set as the minimum injection period. Then, the split injection control is carried out in accordance with the injection period that is set after a lapse of a certain period.
[0056] < Advantages of Fuel Injection Control of Third Embodiment A degree of atomization of the fuel, which is injected by the each injection, depends on the remaining amount of the fuel in the sack (hereinafter the "remaining fuel amount") upon the initiation of the each injection. That is, as the remaining fuel amount is large, the degree of atomization of the fuel, which is injected by the each injection, is increased. In the third embodiment, the injection period of the each injection is set at least equal to the minimum injection period, which is set in accordance with the remaining fuel amount. Therefore, the fuel that is injected by the each injection can reliably and favorably be atomized. [0057] Application Range of Third Embodiment In the third embodiment, for example, the remaining fuel amount is estimated on the basis of the injection period of the last injection before the each injection, and an interval between the time at which the last injection is terminated and a time at which the present injection is started. The last injection before the each injection refers to the last injection in the previous split injection for the initial injection. For the second injection, the last injection before the each injection refers to the initial injection. For the third injection, the last injection before the each injection refers to the second injection. For the fourth injection, the last injection before the each injection refers to the third injection. In addition, it is estimated that the remaining fuel amount is large as the injection period of the last injection before the each injection is long. Furthermore, it is estimated that the remaining fuel amount is small as the above interval is long. Accordingly, it is possible to precisely estimate the remaining fuel amount.
[0058] <Fuel Injection Control Flow of Third Embodiment A description will be made on a fuel injection control flow of the third embodiment. An example of the flow is shown in FIG. 13. Once the flow in FIG. 13 is initiated, first in step 20, the target injection amount Qt and the target split number Ndt, each of which corresponds to the engine speed N and the engine load L, are respectively obtained from the maps in FIG. 7A and FIG. 7B. Next, in step 21, the target split injection amounts Qdlt to Qd4t of the initial injection to the fourth injection are calculated on the basis of the target injection amount Qt and the target split number Ndt that are obtained in step 20. Next, in step 22, the injection periods TAUdl to TAUd4 of the initial injection to the fourth injection are calculated on the basis of the target split injection amount Qdlt to Qd4t that are calculated in step 21.
[0059] Next in step 23, it is determined whether the injection period TAUdl of the initial injection, which is calculated in step 22, is shorter than a corresponding minimum injection period MINI (TAUdl < MINI). Here, if it is determined that TAUdl < MINI is satisfied, the flow proceeds to step 24, the minimum injection period MINI is input as the injection period TAUdl of the initial injection, and the flow proceeds to step 26. On the other hand, if it is determined that TAUdl < MINI is not satisfied, the flow proceeds to step 25, the injection period TAUdl that is calculated in step 22 is input as the injection period TAUdl in the initial injection, and the flow proceeds, to step 26.
[0060] In step 26, it is determined whether the injection period TAUd2 of the second, injection, which is calculated in. step 22, is shorter than a corresponding minimum injection period MIN2 (TAUd2.< MIN2). Here, if it is determined that TAUd2 < MIN2 is satisfied, the flow proceeds to step 27, the minimum injection period MIN2 is input as the injection period TAUd2 of the second injection, and the flow proceeds to step 29. On the other hand, if it is determined that TAUd2 < MIN2 is not satisfied, the flow proceeds to step 28, the injection period TAUd2 that is calculated in the step 22 is input as the injection period TAUd2 of the second injection, and the flow proceeds to step 29.
[0061] In step 29, it is determined whether the injection period TAUd3 of the third injection, which is calculated in step 22, is shorter than a corresponding minimum injection period MIN3 (TAUd3 < MIN3). Here, if it is determined that TAUd3 < MIN3 is satisfied, the flow proceeds to step 30, the minimum injection period MIN3 is input as the injection period TAUd3 of the third injection, and the flow proceeds to step 32. On the other hand, if it is determined that TAUd3 < MIN3 is not satisfied, the flow proceeds to step 31, the injection period TAUd3 that is calculated in step 22 is input as the injection period TAUd3 of the third injection, and the flow proceeds to step 32.
[0062] In step 32, it is determined whether the injection period TAUd4 of the fourth injection, which is calculated in step 22, is shorter than a corresponding minimum injection period MIN4 (TAUd4 < MIN4). Here, if it is determined that TAUd4 < MIN4 is satisfied, the flow proceeds to step 33, the minimum injection period MIN4 is input as the injection period TAUd4 of the fourth injection, and the flow proceeds to step 35. On the other hand, if it is determined that TAUd4 < MIN4 is not satisfied, the flow proceeds to step 34, the injection period TAUd4 that is calculated in step 22 is input as the injection period TAUd4 of the fourth injection, and the flow proceeds to step 35. [0063] In step 35, the split injection is carried out in accordance with the injection periods TAUdl to TAUd4, and the flow is terminated.
[0064] <Application Range of The Invention> The present invention has been described above in the case where the fuel injection valve is attached to the portion of the engine main body on the side of the air intake valve in the upper side of the cylinder as an example. However, the present invention can also be adopted for a case where the fuel injection valve is attached to any portion of the engine main body as long as the fuel injection valve directly injects the fuel into the cylinder.
[0065] <Summary of The Invention> From the above description, the control apparatus of each of the above embodiments can be said as a control apparatus applied to the internal combustion engine that includes the fuel injection valve (for example, the fuel injection valve 11) for directly injecting the fuel into the cylinder in a broader sense. The control apparatus of each of the above embodiments includes a control section (for example, the ECU 90) for executing the split injection control that continuously carries out the partial lift injection, in which" the needle valve 31 starts being closed before the lift amount thereof reaches the maximum lift amount, for multiple times. In the split injection control, the control section sets the injection period TAUdl of the initial injection to be longer than the injection periods TAUd2 to TAUd4 of the second injection onward.
[0066] Alternatively, the control apparatus of each of the above embodiments can be said as a control apparatus applied to the internal combustion engine that includes the fuel injection valve (for example, the fuel injection valve 11) for directly injecting the fuel into the cylinder. The control apparatus of each of the above embodiments includes the control section (for example, the ECU 90) for executing the split injection control that continuously carries out the partial lift injection, in which the needle valve 31 starts being closed before the lift amount thereof reaches the maximum lift amount, for multiple times. In the split injection control, the control section sets the injection period TAUdl of the initial injection to be longer than the reference injection period that is the injection period of the one injection when the target injection amount injected by the split injection control is equally divided by the target split number for injection.

Claims

1. A control device for an internal combustion engine including a fuel injection valve that directly injects fuel into a cylinder, the control device comprising:
an electronic control unit configured to carry out a split injection control, the split injection control being injection control that continuously carries out partial lift injection for multiple times, in which a needle valve of the fuel injection valve starts to close before a lift amount of the needle valve reaches a maximum lift amount, and
the electronic control unit being configured to set an injection period .of initial injection longer than an injection period of each subsequent injection in the split injection control.
2. A control device for an internal combustion engine including a fuel injection valve that directly injects fuel into a cylinder, the control device comprising:
an electronic control unit configured to carry out a split injection control, the split injection control being injection control that continuously carries out partial lift injection for multiple times, in which a needle valve of the fuel injection valve starts to close before a lift amount of the needle valve reaches a maximum lift amount,
the electronic control unit being configured to calculate a target injection amount injected by the split injection control,
the electronic control unit being configured to calculate a reference injection period that is a single injection period obtained by equally dividing the target injection amount by the number of split injection, and
the electronic control unit being configured to set an injection period of initial injection longer than the reference injection period.
3. The control device according to claim 1 or 2, wherein the electronic control unit is configured to set the injection period of the initial injection equal to or longer than a period in which the lift amount of the needle valve reaches a full lift amount.
4. The control device any one of claims 1 to 3, wherein the electronic control unit is configured to calculate a minimum injection period for each injection in the split injection control based on an amount of fuel remaining in a sack of the fuel injection valve when the each injection is initiated, and
the electronic control unit configured to set the injection period of the each injection t equal to or longer than a corresponding minimum injection period in the split injection control respectively.
5. The control device according to claim 4, wherein the electronic control unit is configured to estimate the amount of fuel remaining in the sack of the fuel injection valve based on an injection period of the last injection before the each injection, and an interval between a time at which the last injection is terminated and a time at which the injection is started.
PCT/IB2014/001730 2013-09-10 2014-09-05 Control device of internal combustion engine WO2015036825A1 (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106194463A (en) * 2015-05-29 2016-12-07 丰田自动车株式会社 Control device and control method for electromotor
CN108368793A (en) * 2015-11-28 2018-08-03 戴姆勒股份公司 Method for running the especially internal combustion engine of automobile
EP3453864A4 (en) * 2016-05-06 2019-06-05 Denso Corporation Fuel injection control device

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6304115B2 (en) * 2015-04-23 2018-04-04 トヨタ自動車株式会社 Fuel injection control device

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5499608A (en) * 1995-06-19 1996-03-19 Caterpillar Inc. Method of staged activation for electronically actuated fuel injectors
WO2002006657A1 (en) * 2000-07-13 2002-01-24 Caterpillar Inc. Method and apparatus for delivering multiple fuel injections to the cylinder of an internal combustion engine
JP2003021024A (en) 2001-07-09 2003-01-24 Denso Corp Fuel injection device
DE10326914A1 (en) * 2003-06-16 2005-01-05 Robert Bosch Gmbh Controlling internal combustion engine fuel injection valve involves controlling valve for closing movement during further injection so valve needle adopts stroke position different from null position
FR2857700A1 (en) * 2003-07-16 2005-01-21 Magneti Marelli Motopropulsion Fuel injectors flow characteristic finding method for internal combustion engine, involves modifying gain/offset of linear zone or table/mathematical relation of non linear zone of flow characteristic, to compensate error
EP2455605A1 (en) * 2010-11-10 2012-05-23 Magneti Marelli S.p.A. Method for determining the injection law of a fuel injector

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5499608A (en) * 1995-06-19 1996-03-19 Caterpillar Inc. Method of staged activation for electronically actuated fuel injectors
WO2002006657A1 (en) * 2000-07-13 2002-01-24 Caterpillar Inc. Method and apparatus for delivering multiple fuel injections to the cylinder of an internal combustion engine
JP2003021024A (en) 2001-07-09 2003-01-24 Denso Corp Fuel injection device
DE10326914A1 (en) * 2003-06-16 2005-01-05 Robert Bosch Gmbh Controlling internal combustion engine fuel injection valve involves controlling valve for closing movement during further injection so valve needle adopts stroke position different from null position
FR2857700A1 (en) * 2003-07-16 2005-01-21 Magneti Marelli Motopropulsion Fuel injectors flow characteristic finding method for internal combustion engine, involves modifying gain/offset of linear zone or table/mathematical relation of non linear zone of flow characteristic, to compensate error
EP2455605A1 (en) * 2010-11-10 2012-05-23 Magneti Marelli S.p.A. Method for determining the injection law of a fuel injector

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106194463A (en) * 2015-05-29 2016-12-07 丰田自动车株式会社 Control device and control method for electromotor
US10697384B2 (en) 2015-05-29 2020-06-30 Toyota Jidosha Kabushiki Kaisha Control device and control method for engine
CN108368793A (en) * 2015-11-28 2018-08-03 戴姆勒股份公司 Method for running the especially internal combustion engine of automobile
EP3453864A4 (en) * 2016-05-06 2019-06-05 Denso Corporation Fuel injection control device

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