WO2021065426A1 - Internal combustion engine - Google Patents

Internal combustion engine Download PDF

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Publication number
WO2021065426A1
WO2021065426A1 PCT/JP2020/034540 JP2020034540W WO2021065426A1 WO 2021065426 A1 WO2021065426 A1 WO 2021065426A1 JP 2020034540 W JP2020034540 W JP 2020034540W WO 2021065426 A1 WO2021065426 A1 WO 2021065426A1
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WO
WIPO (PCT)
Prior art keywords
fuel injection
fuel
injection
internal combustion
combustion engine
Prior art date
Application number
PCT/JP2020/034540
Other languages
French (fr)
Japanese (ja)
Inventor
河合謹
脇坂佳史
堀田義博
Original Assignee
株式会社豊田自動織機
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 株式会社豊田自動織機 filed Critical 株式会社豊田自動織機
Priority to CN202080068961.XA priority Critical patent/CN114502826A/en
Priority to AU2020357145A priority patent/AU2020357145A1/en
Priority to EP20872232.2A priority patent/EP4039956A4/en
Publication of WO2021065426A1 publication Critical patent/WO2021065426A1/en

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Classifications

    • 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
    • F02M43/00—Fuel-injection apparatus operating simultaneously on two or more fuels, or on a liquid fuel and another liquid, e.g. the other liquid being an anti-knock additive
    • F02M43/04—Injectors peculiar thereto
    • 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
    • F02B47/00—Methods of operating engines involving adding non-fuel substances or anti-knock agents to combustion air, fuel, or fuel-air mixtures of engines
    • F02B47/02—Methods of operating engines involving adding non-fuel substances or anti-knock agents to combustion air, fuel, or fuel-air mixtures of engines the substances being water or steam
    • 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
    • F02M25/00—Engine-pertinent apparatus for adding non-fuel substances or small quantities of secondary fuel to combustion-air, main fuel or fuel-air mixture
    • F02M25/022—Adding fuel and water emulsion, water or steam
    • F02M25/032—Producing and adding steam
    • F02M25/038—Producing and adding steam into the cylinder or the pre-combustion chamber
    • 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
    • F02M45/00—Fuel-injection apparatus characterised by having a cyclic delivery of specific time/pressure or time/quantity relationship
    • F02M45/02—Fuel-injection apparatus characterised by having a cyclic delivery of specific time/pressure or time/quantity relationship with each cyclic delivery being separated into two or more parts
    • F02M45/04—Fuel-injection apparatus characterised by having a cyclic delivery of specific time/pressure or time/quantity relationship with each cyclic delivery being separated into two or more parts with a small initial part, e.g. initial part for partial load and initial and main part for full load
    • F02M45/08—Injectors peculiar thereto
    • 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
    • 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
    • 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

Definitions

  • the present invention relates to an internal combustion engine.
  • the fuel injection valve is attached to the cylinder head of the internal combustion engine.
  • the fuel injection valve is inserted and arranged from above the cylinder head, and directly injects the high-pressure fuel supplied from the common rail into the combustion chamber.
  • a duct formed of a hollow pipe is attached immediately after each fuel injection port of the fuel injection valve.
  • the present invention was devised in view of these points, and delays the time until ignition of the fuel injected from the fuel injection valve with a simple configuration without deteriorating combustion robustness and fuel efficiency. It is an object of the present invention to provide an internal combustion engine capable of reducing smoke.
  • the first invention of the present invention is to supply a fuel injection valve that injects fuel in the combustion chamber of an internal combustion engine and a cooling medium that supplies a liquid that is inferior in ignitability to the fuel into the combustion chamber.
  • the liquid is supplied to a predetermined area around a plurality of fuel injection ports of the fuel injection valve by the cooling medium supply device before the fuel injection valve performs main injection of fuel.
  • An internal combustion engine that lowers the temperature in a predetermined area.
  • the predetermined region is the fuel injection region rather than the ignition region where the fuel of the main injection injected from the fuel injection valve is ignited. It is an internal combustion engine, which is the area on the mouth side.
  • the third invention of the present invention is the internal combustion engine according to the first invention or the second invention, in which the cooling medium supply device is a sub-injection that injects the liquid into the predetermined region in the combustion chamber. It has a valve, and includes an injection control device that controls fuel injection by the fuel injection valve and controls injection of the liquid by the sub-injection valve. After the injection, the fuel injection control unit that controls the main injection, and the liquid after the pre-injection is performed a plurality of times and before the sub-injection valve performs the main injection. It is an internal combustion engine having a cooling medium injection control unit that controls injection into a predetermined region.
  • the fourth invention of the present invention is a cylinder in which a through hole is formed in which the fuel injection valve is arranged facing the combustion chamber in the internal combustion engine according to the first invention or the second invention.
  • the cooling medium supply device including a head is formed of a porous material containing unglazed ceramics in a tubular shape, and is fitted into the through hole so that the lower end thereof faces the combustion chamber, and the fuel injection valve.
  • An internal combustion engine that exudes and supplies the liquid to predetermined regions around the plurality of fuel injection ports to lower the temperature of the predetermined regions.
  • the fifth invention of the present invention is the internal combustion engine according to any one of the first to fourth inventions, wherein the liquid tank is arranged outside the internal combustion engine and stores the liquid.
  • An internal combustion engine including a liquid supply device for supplying the liquid from the liquid tank to the cooling medium supply device.
  • the sixth invention of the present invention is an internal combustion engine according to any one of the first to fifth inventions, wherein the liquid is a non-combustible liquid containing water. ..
  • a liquid having a lower ignitability than the fuel is placed in a predetermined area around a plurality of fuel injection ports of the fuel injection valve by a cooling medium supply device. Is supplied, and the temperature of a predetermined region is lowered by the latent heat of evaporation of this liquid.
  • the temperature of a predetermined region around the plurality of fuel injection ports of the fuel injection valve is lowered, so that the time until the fuel is ignited within the predetermined region is reduced. It can be delayed, the mixing of the injected fuel and air is promoted, and smoke can be reduced.
  • the predetermined region where the temperature drops due to the latent heat of evaporation of the liquid is around a plurality of fuel injection ports of the fuel injection valve, even if the temperature is lowered excessively, high-temperature gas exists near the wall surface of the combustion chamber. , Misfire can be suppressed, and combustion robustness and fuel efficiency are not deteriorated. Further, since the liquid needs to be supplied only around the plurality of fuel injection ports of the fuel injection valve, the consumption of the liquid can be suppressed.
  • a predetermined region around the plurality of fuel injection ports of the fuel injection valve is a region on the fuel injection port side with respect to the ignition region where the fuel of the main injection injected from the fuel injection valve ignites. ..
  • an auxiliary injection valve for injecting a liquid into a predetermined area around a plurality of fuel injection ports is provided in a combustion chamber, and an injection control device performs a plurality of pre-injections via the fuel injection valve. After the fuel injection valve, the liquid can be injected into a predetermined region before the main injection is performed. As a result, when the fuel injection valve performs the main injection of fuel, the temperature of a predetermined region around the plurality of fuel injection ports of the fuel injection valve can be reliably lowered.
  • the cylinder head is provided with a tubular member formed in a tubular shape with a porous material containing unglazed ceramics through which a fuel injection valve is inserted, and a supply member is used to reach the upper end of the tubular member.
  • the liquid is supplied.
  • the liquid exuded from the lower end of the tubular member is supplied to a predetermined region around the plurality of fuel injection ports of the fuel injection valve, and the temperature of the predetermined region is lowered by the heat of vaporization of the liquid.
  • the liquid is stored in a liquid tank arranged outside the internal combustion engine, and is supplied to the cooling medium supply device by the liquid supply device.
  • the liquid since the liquid is a non-combustion liquid containing water, it receives heat (heat recovery) from the gas in the combustion chamber, vaporizes it, cools a predetermined area, and then directly receives heat (heat) from the combustion flame. (Recovery) can increase vaporization and expansion, which in turn can improve fuel efficiency.
  • an intake flow rate detecting device 21 (for example, an intake flow rate sensor) is provided on the inflow side of the intake pipe 11A.
  • the intake flow rate detection device 21 outputs a detection signal according to the flow rate of the air sucked by the internal combustion engine 10 to the control device 50 (injection control device, fuel injection control unit, and cooling medium injection control unit) included in the internal combustion engine 10.
  • the intake air flow rate detecting device 21 is provided with an intake air temperature detecting device 28A (for example, an intake air temperature sensor).
  • the intake air temperature detection device 28A outputs a detection signal according to the temperature of the intake air passing through the intake air flow rate detection device 21 to the control device 50.
  • the outflow side of the intake pipe 11A is connected to the inflow side of the compressor 35, and the outflow side of the compressor 35 is connected to the inflow side of the intake pipe 11B.
  • the turbocharger 30 includes a compressor 35 having a compressor impeller 35A and a turbine 36 having a turbine impeller 36A.
  • the compressor impeller 35A is rotationally driven by the turbine impeller 36A, which is rotationally driven by the exhaust gas, and supercharges the intake air that has flowed in from the intake pipe 11A by pumping it to the intake pipe 11B.
  • a compressor upstream pressure detection device 24A is provided in the intake pipe 11A on the upstream side of the compressor 35.
  • the compressor upstream pressure detection device 24A is, for example, a pressure sensor, and outputs a detection signal corresponding to the pressure in the intake pipe 11A on the upstream side of the compressor 35 to the control device 50.
  • a compressor downstream pressure detection device 24B is provided in the intake pipe 11B (position between the compressor 35 and the intercooler 16 in the intake pipe 11B) on the downstream side of the compressor 35.
  • the compressor downstream pressure detection device 24B is, for example, a pressure sensor, and outputs a detection signal corresponding to the pressure in the intake pipe 11B on the downstream side of the compressor 35 to the control device 50.
  • the intercooler 16 is arranged on the upstream side, and the throttle device 47 is arranged on the downstream side of the intercooler 16.
  • the intercooler 16 is arranged on the downstream side of the compressor downstream pressure detection device 24B, and lowers the temperature of the intake air supercharged by the compressor 35.
  • An intake air temperature detection device 28B (for example, an intake air temperature sensor) is provided between the intercooler 16 and the throttle device 47.
  • the intake air temperature detection device 28B outputs a detection signal corresponding to the temperature of the intake air whose temperature has been lowered by the intercooler 16 to the control device 50.
  • the throttle device 47 drives the throttle valve 47A that adjusts the opening degree of the intake pipe 11B based on the control signal from the control device 50, and the intake flow rate can be adjusted.
  • the control device 50 outputs a control signal to the throttle device 47 based on the detection signal from the throttle opening detection device 47S (for example, the throttle opening sensor) and the target throttle opening, and the throttle provided in the intake pipe 11B.
  • the opening degree of the valve 47A can be adjusted.
  • the control device 50 obtains a target throttle opening degree based on the accelerator pedal depression amount detected based on the detection signal from the accelerator pedal depression amount detection device 25 and the operating state of the internal combustion engine 10.
  • the accelerator pedal depression amount detection device 25 is, for example, an accelerator pedal depression angle sensor, and is provided on the accelerator pedal.
  • the control device 50 can detect the amount of depression of the accelerator pedal by the driver based on the detection signal from the accelerator pedal depression amount detection device 25.
  • a pressure detection device 24C is provided on the downstream side of the throttle device 47 in the intake pipe 11B, and the outflow side of the EGR pipe 13 is connected to the pressure detection device 24C.
  • the outflow side of the intake pipe 11B is connected to the inflow side of the intake manifold 11C, and the outflow side of the intake manifold 11C is connected to the inflow side of the internal combustion engine 10.
  • the pressure detection device 24C is, for example, a pressure sensor, and outputs a detection signal corresponding to the pressure of the intake air immediately before flowing into the intake manifold 11C to the control device 50.
  • the EGR gas flowing in from the inflow side (connection portion with the exhaust pipe 12B) of the EGR pipe 13 is discharged into the intake pipe 11B.
  • the path through which the EGR gas formed in the EGR pipe 13 flows corresponds to the EGR path.
  • the internal combustion engine 10 has a plurality of cylinders 45A to 45D, and fuel injection valves 43A to 43D are provided in the respective cylinders 45A to 45D. Fuel is supplied to the fuel injection valves 43A to 43D via the common rail 41 and the fuel pipes 42A to 42D. The fuel injection valves 43A to 43D are driven by a control signal from the control device 50, and the respective cylinders 45A. Fuel is injected within ⁇ 45D.
  • each cylinder 45A to 45D is provided with auxiliary injection valves 63A to 63D (cooling medium supply device).
  • Water non-combustion liquid
  • the sub-injection valves 63A to 63D are control signals from the control device 50. Driven by, water is injected into the respective cylinders 45A-45D.
  • the water supply common rail 61 is connected to a water tank (liquid tank) 67 arranged apart from the internal combustion engine 10 via a supply pipe 65 and a water pump (liquid supply device) 66.
  • the water pump 66 is an electric pump that is rotationally driven by a drive signal from the control device 50, and can rotate in either the forward or reverse direction.
  • the forward rotation of the water pump 66 sucks up the water (non-combustion liquid) 68 in the water tank 67, and the water 68 is supplied to the water supply common rail 61 via the supply pipe 65. Further, the water 68 in the water supply common rail 61 and the supply pipe 65 is sucked back by the reverse rotation of the water pump 66 and flows into the water tank 67.
  • the supply pipe 65 may be provided with a water pressure sensor that detects the pressure of the water 68 in the supply pipe 65.
  • a level gauge (remaining amount detecting device) 69 for detecting the remaining amount (water level) of the water 68 stored in the water tank 67 is provided in the water tank 67.
  • the level gauge (remaining amount detecting device) 69 controls a signal (for example, a signal corresponding to level 10 to level 1) according to the remaining amount of water 68 in the water tank 67 reduced from full. Output to ECU) 50.
  • the internal combustion engine 10 is provided with a rotation detection device 22, a coolant temperature detection device 28C, and the like.
  • the rotation detection device 22 is, for example, a rotation sensor, and outputs a detection signal corresponding to the rotation angle (that is, the crank angle) of the crankshaft of the internal combustion engine 10 to the control device 50.
  • the rotation detection device 22 generates an output pulse every time the crankshaft rotates 15 degrees, and this output pulse is input to the control device 50.
  • the control device 50 calculates the crank angle and the engine speed from the output pulse of the rotation detection device 22.
  • the coolant temperature detection device 28C is, for example, a temperature sensor, detects the temperature of the cooling coolant circulating in the internal combustion engine 10, and outputs a detection signal corresponding to the detected temperature to the control device 50.
  • the inflow side of the exhaust manifold 12A is connected to the exhaust side of the internal combustion engine 10, and the inflow side of the exhaust pipe 12B is connected to the outflow side of the exhaust manifold 12A.
  • the outflow side of the exhaust pipe 12B is connected to the inflow side of the turbine 36, and the outflow side of the turbine 36 is connected to the inflow side of the exhaust pipe 12C.
  • the inflow side of the EGR pipe 13 is connected to the exhaust pipe 12B.
  • the EGR pipe 13 communicates the exhaust pipe 12B and the intake pipe 11B, and can recirculate a part of the exhaust gas of the exhaust pipe 12B (corresponding to the exhaust path) to the intake pipe 11B (corresponding to the intake path). .. Further, the EGR pipe 13 is provided with a route switching device 14A, a bypass pipe 13B, an EGR cooler 15, and an EGR valve 14B.
  • the route switching device 14A bypasses the EGR cooler 15 in the bypass pipe 13B and the EGR cooler path that returns the EGR gas flowing from the exhaust pipe 12B to the EGR pipe 13 to the intake path via the EGR cooler 15. It is a path switching valve that switches the bypass path back to the intake pipe 11B based on the control signal from the control device 50.
  • the bypass pipe 13B is provided so as to bypass the EGR cooler 15, the inflow side is connected to the route switching device 14A, and the outflow side is connected to the EGR pipe 13 between the EGR valve 14B and the EGR cooler 15. There is.
  • the EGR valve 14B (EGR valve) is provided on the downstream side of the EGR cooler 15 in the EGR pipe 13 and on the downstream side of the confluence portion between the EGR pipe 13 and the bypass pipe 13B. Then, the EGR valve 14B adjusts the flow rate of the EGR gas flowing in the EGR pipe 13 by adjusting the opening degree of the EGR pipe 13 based on the control signal from the control device 50.
  • the EGR cooler 15 is provided in the EGR pipe 13 between the confluence of the EGR pipe 13 and the bypass pipe 13B and the route switching device 14A.
  • the EGR cooler 15 is a so-called heat exchanger, and a coolant for cooling is supplied to cool the inflowed EGR gas and discharge it.
  • the exhaust pipe 12B is provided with an exhaust temperature detection device 29.
  • the exhaust temperature detection device 29 is, for example, an exhaust temperature sensor, and outputs a detection signal corresponding to the exhaust temperature to the control device 50.
  • the control device 50 has the EGR pipe 13 and the EGR cooler 15 (or bypass pipe 13B) and the EGR cooler 15 (or bypass pipe 13B) based on the exhaust temperature detected by the exhaust temperature detection device 29, the control state of the EGR valve 14B, the operating state of the internal combustion engine 10, and the like.
  • the temperature of the EGR gas flowing into the intake pipe 11B via the EGR valve 14B can be estimated.
  • the outflow side of the exhaust pipe 12B is connected to the inflow side of the turbine 36, and the outflow side of the turbine 36 is connected to the inflow side of the exhaust pipe 12C.
  • the turbine 36 is provided with a variable nozzle 33 capable of controlling the flow velocity of the exhaust gas leading to the turbine impeller 36A, and the opening degree of the variable nozzle 33 is adjusted by the nozzle driving device 31.
  • the control device 50 outputs a control signal to the nozzle drive device 31 based on the detection signal from the nozzle opening detection device 32 (for example, the nozzle opening sensor) and the target nozzle opening to determine the opening of the variable nozzle 33. It is adjustable.
  • the turbine upstream pressure detection device 26A is provided in the exhaust pipe 12B on the upstream side of the turbine 36.
  • the turbine upstream pressure detection device 26A is, for example, a pressure sensor, and outputs a detection signal corresponding to the pressure in the exhaust pipe 12B on the upstream side of the turbine 36 to the control device 50.
  • a turbine downstream pressure detecting device 26B is provided in the exhaust pipe 12C on the downstream side of the turbine 36.
  • the turbine downstream pressure detection device 26B is, for example, a pressure sensor, and outputs a detection signal corresponding to the pressure in the exhaust pipe 12C on the downstream side of the turbine 36 to the control device 50.
  • An exhaust gas purification device (not shown) is connected to the outflow side of the exhaust pipe 12C.
  • the exhaust gas purification device includes an oxidation catalyst, a particulate filter, a selective reduction catalyst, and the like.
  • the control device (ECU: Electronic Control Unit) 50 has at least a processor 51 (CPU, MPU (Micro-Processing Unit), etc.) and a storage device 53 (DRAM, ROM, EEPROM, SRAM, hard disk, etc.).
  • the control device 50 (ECU) is not limited to the detection device and the actuator shown in FIG. 1, and detects the operating state of the internal combustion engine 10 based on the detection signals from various detection devices including the above-mentioned detection device. Controls various actuators including the fuel injection valves 43A to 43D, the auxiliary injection valves 63A to 63D, the EGR valve 14B, the path switching device 14A, the nozzle drive device 31, and the throttle device 47.
  • the storage device 53 stores, for example, programs, parameters, and the like for executing various processes.
  • the atmospheric pressure detection device 23 is, for example, an atmospheric pressure sensor and is provided in the control device 50.
  • the atmospheric pressure detection device 23 outputs a detection signal corresponding to the atmospheric pressure around the control device 50 to the control device 50.
  • the vehicle speed detection device 27 is, for example, a vehicle speed detection sensor, which is provided on the wheels of the vehicle or the like. The vehicle speed detection device 27 outputs a detection signal according to the rotation speed of the wheels of the vehicle to the control device 50.
  • the mounting structures of the fuel injection valves 43A to 43D and the sub-injection valves 63A to 63D will be described with reference to FIG. Since the mounting structures of the fuel injection valves 43A to 43D and the sub-injection valves 63A to 63D are almost the same mounting structures, the mounting structures of the fuel injection valves 43A and the sub-injection valves 63A will be described.
  • the internal combustion engine 10 includes a cylinder block 71 in which a cylinder 45A or the like is formed, and a cylinder head 72.
  • a piston 73 that reciprocates in the cylinder 45A is arranged in the cylinder 45A.
  • a combustion chamber 75 through which the air-fuel mixture burns is formed in the cylinder 45A between the piston 73 and the cylinder head 72.
  • a concave cavity 76 is formed on the top surface of the piston 73.
  • the fuel injection valve 43A is arranged in the center of the upper wall surface of the combustion chamber 75 so that the fuel F is directly injected from the fuel injection valve 43A toward the peripheral portion in the cavity 76 formed in the piston 73. It is configured (see the right figure in FIG. 2).
  • the sub-injection valve 63A is arranged in the peripheral portion of the upper wall surface of the combustion chamber 75 at an angle with respect to the fuel injection valve 43A, and from the sub-injection valve 63A, a plurality of fuel injection valves 43A (for example, for example). It is configured to inject (supply) water 68, which is a liquid inferior in ignitability to fuel F, to a predetermined region FL around the fuel injection ports 49 (see FIGS. 7 and 8) of (8).
  • the predetermined region FL around the plurality of fuel injection ports 49 (see FIGS. 7 and 8) of the fuel injection valve 43A is cooled to a temperature lower than the ignition temperature of the fuel F by the heat of vaporization of the water 68.
  • the sub-injection valves 63A to 63D make water 68 (see FIG. 2).
  • An example of the water injection control process for injecting the fuel will be described with reference to FIGS. 3 to 8.
  • the control device 50 repeatedly executes the processing procedure shown in the flowcharts of FIGS. 3 and 4 at predetermined time intervals (for example, at intervals of several tens of msec to several 100 msec).
  • step S11 the control device 50 uses the accelerator pedal based on the detection values of the accelerator pedal depression amount detection device 25, the rotation detection device 22, the coolant temperature detection device 28C, and the like.
  • the stepping amount (required load), engine speed NE, crank angle, temperature of the cooling coolant, and the like are calculated and stored in the RAM, and then the process proceeds to step S12.
  • step S12 the control device 50 reads the fuel injection flag from the RAM and determines whether or not it is set to "ON", that is, the first pre-injection J1, the second pre-injection J2, and the main injection JM1 (FIG. 5). (Refer to), it is determined whether or not each fuel injection amount and fuel injection start time are set.
  • the fuel injection flag is set to "OFF” and stored in the RAM when the control device 50 is started. Then, when it is determined that the fuel injection flag is set to "ON" (S12: YES), the control device 50 proceeds to step S22, which will be described later.
  • step S13 the control device 50 determines the fuel injection amounts Q2 of the first pre-injection J1 and the second pre-injection J2, and the main injection JM1 based on the required load and the engine speed NE acquired in step S11. After acquiring the fuel injection amount Q3 and storing it in the RAM, the process proceeds to step S14.
  • the optimum fuel injection amounts Q2 of the first pre-injection J1 and the second pre-injection J2 for the required load and the engine speed NE, and the fuel injection amount Q3 of the main injection JM1 are obtained in advance by a test.
  • the relationship between the required load and engine speed NE and each fuel injection amount Q2 and Q3 is stored in a map or the like.
  • the control device 50 may calculate each fuel injection amount Q2 and Q3 with reference to the map. Further, the temperature of each fuel injection amount Q2 and Q3 may be corrected based on the detected value of the temperature of the cooling coolant.
  • step S14 the control device 50 acquires the fuel injection start timings of the first pre-injection J1, the second pre-injection J2, and the main injection JM1 based on the required load and the engine speed NE acquired in step S11. Then, after storing in the RAM, the process proceeds to step S15.
  • the optimum fuel injection start timings of the first pre-injection J1, the second pre-injection J2, and the main injection JM1 for the required load and the engine rotation speed NE are acquired in advance by a test, and the required load and the engine rotation are obtained.
  • the relationship between the number NE and each fuel injection start time is stored in a map or the like.
  • the control device 50 may calculate the fuel injection start timing of each of the first pre-injection J1, the second pre-injection J2, and the main injection JM1 with reference to the map. Further, the fuel injection start timings of the first pre-injection J1, the second pre-injection J2, and the main injection JM1 may be temperature-corrected based on the detected value of the temperature of the cooling coolant.
  • the fuel injection start timing of the main injection JM1 is such that the fuel injection amount from each fuel injection port 49 of the fuel injection valves 43A to 43D reaches the maximum value at the compression top dead center TDC, for example. Is set to. Then, at the fuel injection start timing of the first pre-injection J1 and the second pre-injection J2, heat generation due to the combustion of the fuel injected by the first pre-injection J1 and the second pre-injection J2 before the start of the main injection JM1 is completely generated. Set to absent or almost absent.
  • the fuel injection start timing of the conventional main injection JM2 is set so that the fuel injection amount from each fuel injection port 49 of the fuel injection valves 43A to 43D reaches the maximum value after the compression top dead center TDC. Therefore, the fuel injection start timing of the main injection JM1 is set to be earlier than the fuel injection start timing of the conventional main injection JM2 by the time T1.
  • step S15 the control device 50 reads the fuel injection flag from the RAM, sets it to "ON”, stores it in the RAM again, and then proceeds to step S16.
  • step S16 the control device 50 reads out the fuel injection amount Q2 of each of the first pre-injection J1 and the second pre-injection J2 and the fuel injection amount Q3 of the main injection JM1 from the RAM, and totals them. The total fuel injection amount is calculated and stored in the RAM. Then, the control device 50 determines whether or not the total fuel injection amount is equal to or higher than the predetermined fuel injection amount threshold value Q1.
  • the fuel injection amount threshold value Q1 is stored in advance in a ROM, EEPROM, or the like that constitutes the storage device 53.
  • step S17 the control device 50 reads the water injection flag from the RAM, sets it to “OFF”, stores it in the RAM again, and then proceeds to step S22 described later.
  • the water injection flag is set to "OFF” and stored in the RAM when the control device 50 is started.
  • step S18 the control device 50 determines whether or not the condition for performing the water injection K1 by the sub-injection valves 63A to 63D is satisfied. For example, when the temperature of the cooling coolant is lower than the predetermined temperature during warm-up operation, or when the required torque is equal to or less than the predetermined torque, the control device 50 performs water injection K1 by the sub-injection valves 63A to 63D. It is determined that the condition is not satisfied.
  • step S19 the control device 50 reads the total fuel injection amount calculated in step S16 from the RAM, and acquires the water injection amount Q5 of the current water injection K1 (see FIG. 5) based on the total fuel injection amount. , After storing in the RAM, the process proceeds to step S20.
  • the optimum water injection amount Q5 of the water injection K1 by the sub-injection valves 63A to 63D with respect to the total fuel injection amount injected by the fuel injection valves 43A to 43D is obtained in advance by a test.
  • the relationship between the total fuel injection amount and the water injection amount Q5 is stored in the map M1.
  • the control device 50 calculates the water injection amount Q5 with reference to the map M1.
  • the water temperature of the water 68 stored in the water tank 67 may be detected by a water temperature sensor or the like to correct the water injection amount Q5.
  • step S20 the control device 50 sets the water injection start timing for the water injection amount Q5 of the water injection K1 by the sub-injection valves 63A to 63D based on the fuel injection start timing of the main injection JM1 of the fuel F acquired in step S14. After acquiring and storing in the RAM, the process proceeds to step S21.
  • water injection with respect to the optimum water injection amount Q5 of the optimum water injection K1 set after the fuel of the second pre-injection J2 is injected and before the fuel injection start timing of the main injection JM1.
  • the start time is acquired in advance by a test, and the relationship between the fuel injection start time of the main injection JM1 and the water injection start time with respect to the water injection amount Q5 of the water injection K1 is stored in a map or the like.
  • the control device 50 may calculate the water injection start timing with respect to the water injection amount Q5 of the water injection K1 with reference to the map.
  • the water injection periods T2 to T3 are set to end before the fuel injection start time (crank angle at time T4) of the main injection JM1.
  • step S21 the control device 50 reads the water injection flag from the RAM, sets it to "ON”, stores it in the RAM again, and then proceeds to step S22.
  • the water injection flag is set to "OFF” and stored in the RAM when the control device 50 is started.
  • step S22 the control device 50 reads the crank angle acquired in step S11 and the fuel injection start timing of the first pre-injection J1 acquired in step S14 from the RAM, and the crank angle is the first pre-injection. It is determined whether or not it is the fuel injection start time (see FIG. 5) of the injection J1.
  • step S23 as shown in FIG. 5, the control device 50 operates the fuel injection valve (for example, the fuel injection valve 43A) this time so as to have the fuel injection amount Q2 of the first pre-injection J1 acquired in step S13. To control. Then, the control device 50 injects the fuel injection amount Q2 of the first pre-injection J1 acquired in step S13, and then ends the process.
  • the fuel injection valve for example, the fuel injection valve 43A
  • step S24 the control device 50 reads the crank angle acquired in step S11 and the fuel injection start timing of the second pre-injection J2 acquired in step S14 from the RAM, and the crank angle is the second pre-injection J2. It is determined whether or not it is the fuel injection start time (see FIG. 5).
  • step S23 as shown in FIG. 5, the control device 50 operates the fuel injection valve (for example, the fuel injection valve 43A) this time so as to have the fuel injection amount Q2 of the second pre-injection J2 acquired in step S13. To control. Then, the control device 50 injects the fuel injection amount Q2 of the second pre-injection J2 acquired in step S13, and then ends the process.
  • the fuel injection valve for example, the fuel injection valve 43A
  • step S25 the control device 50 reads the water injection flag from the RAM and whether or not it is set to "ON", that is, whether or not the water injection amount Q5 and the water injection start timing of the current water injection K1 are set. Judge whether or not. Then, when it is determined that the water injection flag is set to "OFF" (S25: NO), the control device 50 proceeds to step S29 described later.
  • step S26 the control device 50 reads the crank angle acquired in step S11 and the water injection start timing of the water injection K1 acquired in step S20 from the RAM, and the crank angle is the water injection start timing of the water injection K1. (Crank angle at time T2 in FIG. 5) is determined.
  • step S27 the control device 50 controls the operation of the sub-injection valve (for example, the sub-injection valve 63A) this time so as to have the water injection amount Q5 of the water injection K1 acquired in step S19.
  • the control device 50 has a plurality of (for example, eight) fuel injection ports 49 (see FIGS. 7 and 8) from the sub-injection valve 63A to the fuel injection valve 43A. It is controlled to inject water 68 having a water injection amount Q5 into a predetermined region FL (see FIGS. 7 and 8) around the water.
  • the predetermined region FL (see FIGS. 7 and 8) around the plurality of fuel injection ports 49 (see FIGS. 7 and 8) of the fuel injection valve 43A is set from the ignition temperature of the fuel F by the heat of vaporization of the water 68. Is also cooled to a low temperature. Then, the control device 50 injects the water injection amount Q5 of the water injection K1 acquired in step S19, and then proceeds to step S28. In step S28, the control device 50 reads the water injection flag from the RAM, sets it to “OFF”, stores it in the RAM again, and then ends the process.
  • step S29 the control device 50 reads the crank angle acquired in step S11 and the fuel injection start timing of the main injection JM1 acquired in step S14 from the RAM, and the crank angle is the fuel injection start timing of the main injection JM1. (Crank angle at time T4 in FIG. 5) is determined. Then, when it is determined that the crank angle is not the fuel injection start time of the main injection JM1 (S29: NO), the control device 50 ends the process.
  • step S30 the control device 50 controls the operation of the fuel injection valve (for example, the fuel injection valve 43A) this time so as to be the fuel injection amount Q3 of the main injection JM1 acquired in step S13.
  • the control device 50 is connected to the piston 73 from a plurality of (for example, eight) fuel injection ports 49 (see FIGS. 7 and 8) of the fuel injection valve 43A.
  • the fuel F of the fuel injection amount Q3 is controlled to be injected toward the peripheral portion in the formed cavity 76.
  • the fuel F injected from each fuel injection port 49 of the fuel injection valve 43A has the ignition temperature of the fuel F due to the heat of vaporization of the water 68 injected from the sub-injection valve 63A. Ignition is delayed until it passes through a predetermined region FL cooled to a lower temperature, and mixing of fuel F and air is promoted. That is, as shown in FIG. 5, the main injection JM1 is injected earlier than the conventional main injection JM2 by the time T1 and passes through the predetermined region FL without ignition. As a result, mixing of the injected fuel F and air is promoted as compared with the conventional case, and smoke can be reduced.
  • the fuel F that has advanced to the outside of the predetermined region FL is ignited in the ignition region FA.
  • the predetermined region FL is a region on the fuel injection port 49 side of the ignition region FA where the fuel F of the main injection JM1 injected from the fuel injection valve 43A ignites.
  • the water 68 injected from the sub-injection valve 63A directly receives heat (heat recovery) from the combustion flame to increase vaporization and expansion, so that the in-cylinder pressure increases after the compression top dead center TDC. It is possible to increase the output torque by increasing the predetermined pressure ⁇ P as compared with the conventional case, and it is possible to improve the fuel efficiency.
  • step S30 after injecting the fuel injection amount Q3 of the main injection JM1 acquired in step S13, the control device 50 proceeds to step S31.
  • step S31 the control device 50 reads the fuel injection flag from the RAM, sets it to “OFF”, stores it in the RAM again, and then ends the process.
  • the water 68 is stored in a water tank 67 (liquid tank) arranged outside the internal combustion engine 10, and is supplied from the water tank 67 to each of the sub-injection valves 63A to 63D by the water pump 66.
  • a water tank 67 liquid tank
  • the water pump 66 supplies from the water tank 67 to each of the sub-injection valves 63A to 63D to the water pump 66.
  • the present invention is not limited to the above-described embodiment, and it goes without saying that various improvements, modifications, additions, and deletions can be made without departing from the gist of the present invention.
  • it may be as follows.
  • the same reference numerals as the internal combustion engine 10 and the like according to the embodiment of FIGS. 1 to 8 indicate the same or equivalent parts as the internal combustion engine 10 and the like according to the embodiment.
  • the fuel injection valves 43A to 43D are formed in a substantially cylindrical shape with a porous material containing unglazed ceramics, and the fuel injection valves 43A to 43D are from above.
  • the tubular member 82 to be fitted may be provided and fitted into the through hole 72A formed in the center of the upper wall surface of each combustion chamber 75 so that the lower end portion of the tubular member 82 faces the combustion chamber 75. That is, the cylinder head 72 may be formed with a through hole 72A in which the fuel injection valves 43A to 43D are arranged so as to face the combustion chamber 75.
  • the length of the tubular member 82 is formed to be substantially the same as the thickness of the cylinder head 72, and the lower end surface of the tubular member 82 is provided so as to be flush with the upper wall surface of the combustion chamber 75.
  • FIG. 9 illustrates a tubular member 82 into which the fuel injection valve 43A is fitted from above.
  • supply members 81 formed in a substantially box shape having a circular cross section open downward are coaxially attached to the cylinder head 72 so as to cover the upper end surface of each of the tubular members 82 over the entire surface. It is provided.
  • a through hole 81A into which the fuel injection valves 43A to 43D are fitted from above is formed in the center of the ceiling portion of each supply member 81.
  • Water pipes 62A to 62D are connected to each of the supply members 81. Then, the fuel injection valves 43A to 43D are fitted and fixed to the through holes 81A of the supply members 81 and the tubular members 82 from above.
  • FIG. 9 illustrates the water pipe 62A.
  • water 68 is supplied to the upper end surface of each tubular member 82 via the water pipes 62A to 62D and each supply member 81, and the water 68 seeps out from the lower end surface of the tubular member 82.
  • the water 68 is supplied to the predetermined region FL around the plurality of fuel injection ports 49 (see FIG. 7) of the fuel injection valves 43A to 43D, and the heat of vaporization of the water 68.
  • the predetermined region FL is cooled to a temperature lower than the ignition temperature of the fuel F.
  • the fuel F of the main injection JM1 injected from each fuel injection port 49 of the fuel injection valve 43A is cooled to a temperature lower than the ignition temperature of the fuel F by the heat of vaporization of water 68. Ignition is delayed until the fuel F passes through the predetermined region FL, and the mixing of the fuel F and the air is promoted. That is, the fuel F of the main injection JM1 passes through the predetermined region FL without ignition. As a result, mixing of the injected fuel F and air is promoted as compared with the conventional case, and smoke can be reduced.
  • the fuel F that has advanced to the outside of the predetermined region FL is ignited in the ignition region FA (see FIGS. 7 and 8). That is, the predetermined region FL is a region on the fuel injection port 49 side of the ignition region FA where the fuel F of the main injection JM1 injected from the fuel injection valve 43A ignites. Further, the water 68 exuding from the lower end surface of the tubular member 82 directly receives heat (heat recovery) from the combustion flame to increase vaporization and expansion, so that the in-cylinder pressure is set higher than before after the compression top dead center TDC.
  • the pressure ⁇ P (see FIG. 5) can be increased to increase the output torque, which in turn can improve fuel efficiency.
  • water 68 is injected into a predetermined region FL around a plurality of (for example, eight) fuel injection ports 49 via the sub-injection valves 63A to 63D, but the water 68 is not limited to the water 68.
  • a liquid such as methanol, which is inferior in ignitability to fuel F such as light oil, may be injected into the predetermined region FL.
  • the inside of the predetermined region FL can be cooled by the heat of vaporization of a liquid such as methanol to promote mixing of the fuel F and air, and smoke can be reduced.
  • a water pump (not shown) of the internal combustion engine 10 may supply a part of the cooling coolant to the sub-injection valves 63A to 63D.
  • a part of the cooling coolant can be supplied to the sub-injection valves 63A to 63D and injected into the predetermined region FL only when the internal combustion engine 10 is driven.

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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)
  • Combined Controls Of Internal Combustion Engines (AREA)
  • Output Control And Ontrol Of Special Type Engine (AREA)
  • Fuel-Injection Apparatus (AREA)

Abstract

The present invention is configured to comprise: fuel injection valves (43A-43D) that inject a fuel (F) in a combustion chamber (75) of an internal combustion engine (10); and cooling medium supply devices (63A-63D) that supply, into the combustion chamber (75), a liquid (68) having ignitibility that is inferior to the fuel (F), wherein before the fuel injection valves (43A-43D) perform main injection (JM1) of the fuel (F), the cooling medium supply devices (63A-63D) supply the liquid (68) to a predetermined region (FL) around a plurality of fuel injection ports (49) of the fuel injection valves, thereby lowering the temperature of the predetermined region (FL).

Description

内燃機関Internal combustion engine
　本発明は、内燃機関に関するものである。 The present invention relates to an internal combustion engine.
　従来より、内燃機関の燃焼室内に燃料を噴射する技術に関し種々提案されている。例えば、下記特許文献１に記載されるダクトを取り付けられた燃料噴射弁では、内燃機関のシリンダヘッドには、燃料噴射弁が取り付けられている。燃料噴射弁は、シリンダヘッドの上方から挿入配置され、コモンレールから供給された高圧燃料を燃焼室へ直接噴射する。また、中空管で形成されたダクトが、燃料噴射弁の各燃料噴射口の直後に取り付けられている。これにより、噴射された燃料がダクトを通過することによって、高温の筒内ガスにさらされないため、着火までの時間を延ばし、燃料と空気の混合を促進させ、スモークの低減を図ることができる。 Conventionally, various technologies for injecting fuel into the combustion chamber of an internal combustion engine have been proposed. For example, in the fuel injection valve to which the duct described in Patent Document 1 below is attached, the fuel injection valve is attached to the cylinder head of the internal combustion engine. The fuel injection valve is inserted and arranged from above the cylinder head, and directly injects the high-pressure fuel supplied from the common rail into the combustion chamber. Further, a duct formed of a hollow pipe is attached immediately after each fuel injection port of the fuel injection valve. As a result, the injected fuel passes through the duct and is not exposed to the high-temperature in-cylinder gas, so that the time until ignition can be extended, the mixture of fuel and air can be promoted, and smoke can be reduced.
米国特許出願公開第２０１７／０１１４９９８号明細書U.S. Patent Application Publication No. 2017/0114998
　しかしながら、前記特許文献１に記載されたダクトを取り付けられた燃料噴射弁では、燃料噴射弁の各燃料噴射口に中空管で形成されたダクトを整列させて取り付ける必要がある。このため、ダクトの取り付け構造が複雑となり、内燃機関の組み立て作業の煩雑化、及び、製造コストが上昇するという問題がある。 However, in the fuel injection valve to which the duct described in Patent Document 1 is attached, it is necessary to align and attach the duct formed by the hollow pipe to each fuel injection port of the fuel injection valve. For this reason, there is a problem that the mounting structure of the duct becomes complicated, the assembly work of the internal combustion engine becomes complicated, and the manufacturing cost increases.
　そこで、本発明は、このような点に鑑みて創案されたものであり、燃焼ロバスト性と燃費を悪化させることなく、簡易な構成で燃料噴射弁から噴射された燃料の着火までの時間を遅らせてスモークを低減できる内燃機関を提供することを目的とする。 Therefore, the present invention was devised in view of these points, and delays the time until ignition of the fuel injected from the fuel injection valve with a simple configuration without deteriorating combustion robustness and fuel efficiency. It is an object of the present invention to provide an internal combustion engine capable of reducing smoke.
　上記課題を解決するため、本発明の第１の発明は、内燃機関の燃焼室で燃料を噴射する燃料噴射弁と、前記燃焼室内に前記燃料よりも着火性が劣る液体を供給する冷却媒体供給装置と、を備え、前記燃料噴射弁が燃料の主噴射を行う前に、前記冷却媒体供給装置によって前記燃料噴射弁の複数の燃料噴射口の周囲の所定領域に前記液体を供給して、前記所定領域の温度を下げる、内燃機関である。 In order to solve the above problems, the first invention of the present invention is to supply a fuel injection valve that injects fuel in the combustion chamber of an internal combustion engine and a cooling medium that supplies a liquid that is inferior in ignitability to the fuel into the combustion chamber. The liquid is supplied to a predetermined area around a plurality of fuel injection ports of the fuel injection valve by the cooling medium supply device before the fuel injection valve performs main injection of fuel. An internal combustion engine that lowers the temperature in a predetermined area.
　次に、本発明の第２の発明は、上記第１の発明に係る内燃機関において、前記所定領域は、前記燃料噴射弁から噴射された主噴射の燃料が着火する着火領域よりも前記燃料噴射口側の領域である、内燃機関である。 Next, in the second invention of the present invention, in the internal combustion engine according to the first invention, the predetermined region is the fuel injection region rather than the ignition region where the fuel of the main injection injected from the fuel injection valve is ignited. It is an internal combustion engine, which is the area on the mouth side.
　次に、本発明の第３の発明は、上記第１の発明又は第２の発明に係る内燃機関において、前記冷却媒体供給装置は、前記燃焼室で前記液体を前記所定領域に噴射する副噴射弁を有し、前記燃料噴射弁による燃料噴射を制御すると共に、前記副噴射弁による前記液体の噴射を制御する噴射制御装置を備え、前記噴射制御装置は、前記燃料噴射弁が複数回のプレ噴射を行った後に、前記主噴射を行うように制御する燃料噴射制御部と、複数回の前記プレ噴射が行われた後に、前記副噴射弁が前記主噴射が行われる前に前記液体を前記所定領域に噴射するように制御する冷却媒体噴射制御部と、を有する、内燃機関である。 Next, the third invention of the present invention is the internal combustion engine according to the first invention or the second invention, in which the cooling medium supply device is a sub-injection that injects the liquid into the predetermined region in the combustion chamber. It has a valve, and includes an injection control device that controls fuel injection by the fuel injection valve and controls injection of the liquid by the sub-injection valve. After the injection, the fuel injection control unit that controls the main injection, and the liquid after the pre-injection is performed a plurality of times and before the sub-injection valve performs the main injection. It is an internal combustion engine having a cooling medium injection control unit that controls injection into a predetermined region.
　次に、本発明の第４の発明は、上記第１の発明又は第２の発明に係る内燃機関において、前記燃焼室に対向して前記燃料噴射弁が配置される貫通孔が形成されたシリンダヘッドを備え、前記冷却媒体供給装置は、素焼きのセラミックスを含む多孔質材で筒状に形成されて、下端部が前記燃焼室に対向するように前記貫通孔に嵌め込まれると共に、前記燃料噴射弁が上方から挿通される筒状部材と、前記シリンダヘッドに設けられて前記筒状部材の上端部に前記液体を供給する供給部材と、を有し、前記筒状部材の下端部から前記液体が染み出て、複数の前記燃料噴射口の周囲の所定領域に前記液体を供給して、前記所定領域の温度を下げる、内燃機関である。 Next, the fourth invention of the present invention is a cylinder in which a through hole is formed in which the fuel injection valve is arranged facing the combustion chamber in the internal combustion engine according to the first invention or the second invention. The cooling medium supply device including a head is formed of a porous material containing unglazed ceramics in a tubular shape, and is fitted into the through hole so that the lower end thereof faces the combustion chamber, and the fuel injection valve. Has a tubular member inserted from above and a supply member provided on the cylinder head to supply the liquid to the upper end portion of the tubular member, and the liquid is supplied from the lower end portion of the tubular member. An internal combustion engine that exudes and supplies the liquid to predetermined regions around the plurality of fuel injection ports to lower the temperature of the predetermined regions.
　次に、本発明の第５の発明は、上記第１の発明乃至第４の発明のいずれか１つに係る内燃機関において、前記内燃機関の外側に配置されて前記液体を貯留する液体タンクと、前記液体タンクから前記冷却媒体供給装置へ前記液体を供給する液体供給装置と、を備えた、内燃機関である。 Next, the fifth invention of the present invention is the internal combustion engine according to any one of the first to fourth inventions, wherein the liquid tank is arranged outside the internal combustion engine and stores the liquid. An internal combustion engine including a liquid supply device for supplying the liquid from the liquid tank to the cooling medium supply device.
　次に、本発明の第６の発明は、上記第１の発明乃至第５の発明のいずれか１つに係る内燃機関において、前記液体は、水を含む非燃焼液体である、内燃機関である。 Next, the sixth invention of the present invention is an internal combustion engine according to any one of the first to fifth inventions, wherein the liquid is a non-combustible liquid containing water. ..
　第１の発明によれば、燃料噴射弁が燃料の主噴射を行う前に、冷却媒体供給装置によって燃料噴射弁の複数の燃料噴射口の周囲の所定領域に、燃料よりも着火性が劣る液体を供給して、この液体の蒸発潜熱によって所定領域の温度を下げる。これにより、燃料噴射弁が燃料の主噴射を行った際に、燃料噴射弁の複数の燃料噴射口の周囲の所定領域の温度が下がっているため、所定領域内における燃料の着火までの時間を遅らすことができ、噴射燃料と空気との混合が促進され、スモークを低減できる。 According to the first invention, before the fuel injection valve performs the main injection of fuel, a liquid having a lower ignitability than the fuel is placed in a predetermined area around a plurality of fuel injection ports of the fuel injection valve by a cooling medium supply device. Is supplied, and the temperature of a predetermined region is lowered by the latent heat of evaporation of this liquid. As a result, when the fuel injection valve performs the main injection of fuel, the temperature of a predetermined region around the plurality of fuel injection ports of the fuel injection valve is lowered, so that the time until the fuel is ignited within the predetermined region is reduced. It can be delayed, the mixing of the injected fuel and air is promoted, and smoke can be reduced.
　また、液体の蒸発潜熱によって温度が下がる所定領域は、燃料噴射弁の複数の燃料噴射口の周囲であるため、過度に温度を下げても、燃焼室壁面付近には、高温のガスが存在し、失火を抑制することができ、燃焼ロバスト性と燃費を悪化させることがない。また、液体は、燃料噴射弁の複数の燃料噴射口の周囲のみに供給すればよいため、液体の消費量を抑えることができる。 Further, since the predetermined region where the temperature drops due to the latent heat of evaporation of the liquid is around a plurality of fuel injection ports of the fuel injection valve, even if the temperature is lowered excessively, high-temperature gas exists near the wall surface of the combustion chamber. , Misfire can be suppressed, and combustion robustness and fuel efficiency are not deteriorated. Further, since the liquid needs to be supplied only around the plurality of fuel injection ports of the fuel injection valve, the consumption of the liquid can be suppressed.
　第２の発明によれば、燃料噴射弁の複数の燃料噴射口の周囲の所定領域は、燃料噴射弁から噴射された主噴射の燃料が着火する着火領域よりも燃料噴射口側の領域である。これにより、燃料噴射弁が燃料の主噴射を行った際に、所定領域内において、噴射燃料と空気との混合が効果的に行われ、スモークの低減を更に図ることができる。 According to the second invention, a predetermined region around the plurality of fuel injection ports of the fuel injection valve is a region on the fuel injection port side with respect to the ignition region where the fuel of the main injection injected from the fuel injection valve ignites. .. As a result, when the fuel injection valve performs the main injection of fuel, the injected fuel and air are effectively mixed within a predetermined region, and smoke can be further reduced.
　第３の発明によれば、燃焼室で複数の燃料噴射口の周囲の所定領域に液体を噴射する副噴射弁を設け、噴射制御装置によって、燃料噴射弁を介して複数回のプレ噴射が行われた後に、燃料噴射弁によって主噴射が行われる前に液体を所定領域に噴射することができる。これにより、燃料噴射弁が燃料の主噴射を行った際に、燃料噴射弁の複数の燃料噴射口の周囲の所定領域の温度を確実に下げることができる。その結果、燃料噴射弁が燃料の主噴射を行った際に、所定領域内における燃料の着火までの時間を遅らすことができ、噴射燃料と空気との混合が促進され、副噴射弁を設ける簡易な構成でスモークを低減することができる。 According to the third invention, an auxiliary injection valve for injecting a liquid into a predetermined area around a plurality of fuel injection ports is provided in a combustion chamber, and an injection control device performs a plurality of pre-injections via the fuel injection valve. After the fuel injection valve, the liquid can be injected into a predetermined region before the main injection is performed. As a result, when the fuel injection valve performs the main injection of fuel, the temperature of a predetermined region around the plurality of fuel injection ports of the fuel injection valve can be reliably lowered. As a result, when the fuel injection valve performs the main injection of the fuel, the time until the fuel is ignited in the predetermined region can be delayed, the mixing of the injected fuel and the air is promoted, and the auxiliary injection valve is simply provided. Smoke can be reduced with various configurations.
　第４の発明によれば、シリンダヘッドに燃料噴射弁が挿通される素焼きのセラミックスを含む多孔質材で筒状に形成された筒状部材を設け、供給部材によって、筒状部材の上端部に液体が供給される。そして、筒状部材の下端部から染み出た液体が、燃料噴射弁の複数の燃料噴射口の周囲の所定領域に供給され、液体の気化熱によって当該所定領域の温度が下がる。これにより、燃料噴射弁が燃料の主噴射を行った際に、燃料噴射弁の複数の燃料噴射口の周囲の所定領域の温度を確実に下げることができる。その結果、燃料噴射弁が燃料の主噴射を行った際に、所定領域内における燃料の着火までの時間を遅らすことができ、噴射燃料と空気との混合が促進され、燃料噴射弁が挿通される筒状部材を設ける簡易な構成でスモークを低減することができる。 According to the fourth invention, the cylinder head is provided with a tubular member formed in a tubular shape with a porous material containing unglazed ceramics through which a fuel injection valve is inserted, and a supply member is used to reach the upper end of the tubular member. The liquid is supplied. Then, the liquid exuded from the lower end of the tubular member is supplied to a predetermined region around the plurality of fuel injection ports of the fuel injection valve, and the temperature of the predetermined region is lowered by the heat of vaporization of the liquid. As a result, when the fuel injection valve performs the main injection of fuel, the temperature of a predetermined region around the plurality of fuel injection ports of the fuel injection valve can be reliably lowered. As a result, when the fuel injection valve performs the main injection of the fuel, the time until the fuel is ignited in the predetermined region can be delayed, the mixture of the injected fuel and the air is promoted, and the fuel injection valve is inserted. Smoke can be reduced by a simple configuration in which a tubular member is provided.
　第５の発明によれば、液体は、内燃機関の外側に配置された液体タンクに貯留され、液体供給装置によって冷却媒体供給装置に供給される。これにより、内燃機関の温度上昇による液体の温度上昇を抑制することができ、燃料噴射弁の複数の燃料噴射口の周囲の所定領域の液体の気化による冷却効果を高めることができる。 According to the fifth invention, the liquid is stored in a liquid tank arranged outside the internal combustion engine, and is supplied to the cooling medium supply device by the liquid supply device. As a result, it is possible to suppress the temperature rise of the liquid due to the temperature rise of the internal combustion engine, and it is possible to enhance the cooling effect due to the vaporization of the liquid in a predetermined region around the plurality of fuel injection ports of the fuel injection valve.
　第６の発明によれば、液体は、水を含む非燃焼液体であるため、燃焼室のガスから受熱（熱回収）して気化して所定領域を冷却した後、燃焼火炎から直接受熱（熱回収）して気化膨張を増大でき、引いては燃費の向上を図ることができる。 According to the sixth invention, since the liquid is a non-combustion liquid containing water, it receives heat (heat recovery) from the gas in the combustion chamber, vaporizes it, cools a predetermined area, and then directly receives heat (heat) from the combustion flame. (Recovery) can increase vaporization and expansion, which in turn can improve fuel efficiency.
本実施形態に係る内燃機関の概略構成を説明する図である。It is a figure explaining the schematic structure of the internal combustion engine which concerns on this embodiment. 燃料噴射弁と副噴射弁の作動の一例を示す断面図である。It is sectional drawing which shows an example of the operation of a fuel injection valve and a sub-injection valve. 制御装置が実行する水噴射制御処理を示す第１フローチャートである。It is a 1st flowchart which shows the water injection control process which a control device executes. 制御装置が実行する水噴射制御処理を示す第２フローチャートである。It is a 2nd flowchart which shows the water injection control process which a control device executes. 筒内圧と燃料噴射量と水噴射量のクランク角度に対する変化の一例を示す図である。It is a figure which shows an example of the change with respect to the crank angle of a cylinder pressure, a fuel injection amount, and a water injection amount. 燃料噴射量に対する水噴射量を決定する水噴射量設定マップの一例を示す図である。It is a figure which shows an example of the water injection amount setting map which determines the water injection amount with respect to the fuel injection amount. 燃料噴射弁から主噴射の燃料が噴射された状態の一例を示す平面図である。It is a top view which shows an example of the state in which the fuel of the main injection is injected from a fuel injection valve. 燃料噴射弁から主噴射の燃料が噴射された状態の一例を示す側面図である。It is a side view which shows an example of the state which the fuel of the main injection is injected from a fuel injection valve. 他の第１実施形態に係る燃料噴射弁と筒状部材の作動の一例を示す断面図である。It is sectional drawing which shows an example of the operation of the fuel injection valve and the tubular member which concerns on another 1st Embodiment.
　以下、本発明に係る内燃機関を具体化した一実施形態に基づき図面を参照しつつ詳細に説明する。先ず、本実施形態に係る内燃機関１０の概略構成について図１に基づいて説明する。本実施形態の説明では、内燃機関１０の例として、車両に搭載された、例えば、ディーゼルエンジンを用いて説明する。 Hereinafter, a detailed description will be given with reference to the drawings based on an embodiment embodying the internal combustion engine according to the present invention. First, a schematic configuration of the internal combustion engine 10 according to the present embodiment will be described with reference to FIG. In the description of the present embodiment, as an example of the internal combustion engine 10, for example, a diesel engine mounted on a vehicle will be described.
　以下、本実施形態に係る内燃機関１０について、吸気側から排気側に向かって順に説明する。図１に示すように、吸気管１１Ａの流入側には、吸気流量検出装置２１（例えば、吸気流量センサ）が設けられている。吸気流量検出装置２１は、内燃機関１０が吸入した空気の流量に応じた検出信号を、内燃機関１０が備える制御装置５０（噴射制御装置、燃料噴射制御部、および冷却媒体噴射制御部）に出力する。また吸気流量検出装置２１には、吸気温度検出装置２８Ａ（例えば、吸気温度センサ）が設けられている。吸気温度検出装置２８Ａは、吸気流量検出装置２１を通過する吸気の温度に応じた検出信号を制御装置５０に出力する。 Hereinafter, the internal combustion engine 10 according to the present embodiment will be described in order from the intake side to the exhaust side. As shown in FIG. 1, an intake flow rate detecting device 21 (for example, an intake flow rate sensor) is provided on the inflow side of the intake pipe 11A. The intake flow rate detection device 21 outputs a detection signal according to the flow rate of the air sucked by the internal combustion engine 10 to the control device 50 (injection control device, fuel injection control unit, and cooling medium injection control unit) included in the internal combustion engine 10. To do. Further, the intake air flow rate detecting device 21 is provided with an intake air temperature detecting device 28A (for example, an intake air temperature sensor). The intake air temperature detection device 28A outputs a detection signal according to the temperature of the intake air passing through the intake air flow rate detection device 21 to the control device 50.
　吸気管１１Ａの流出側はコンプレッサ３５の流入側に接続され、コンプレッサ３５の流出側は吸気管１１Ｂの流入側に接続されている。ターボ過給機３０は、コンプレッサインペラ３５Ａを有するコンプレッサ３５と、タービンインペラ３６Ａを有するタービン３６とを備えている。コンプレッサインペラ３５Ａは、排気ガスによって回転駆動されるタービンインペラ３６Ａにて回転駆動され、吸気管１１Ａから流入された吸気を吸気管１１Ｂに圧送することで過給する。 The outflow side of the intake pipe 11A is connected to the inflow side of the compressor 35, and the outflow side of the compressor 35 is connected to the inflow side of the intake pipe 11B. The turbocharger 30 includes a compressor 35 having a compressor impeller 35A and a turbine 36 having a turbine impeller 36A. The compressor impeller 35A is rotationally driven by the turbine impeller 36A, which is rotationally driven by the exhaust gas, and supercharges the intake air that has flowed in from the intake pipe 11A by pumping it to the intake pipe 11B.
　コンプレッサ３５の上流側となる吸気管１１Ａには、コンプレッサ上流圧力検出装置２４Ａが設けられている。コンプレッサ上流圧力検出装置２４Ａは、例えば、圧力センサであり、コンプレッサ３５の上流側となる吸気管１１Ａ内の圧力に応じた検出信号を制御装置５０に出力する。コンプレッサ３５の下流側となる吸気管１１Ｂ（吸気管１１Ｂにおけるコンプレッサ３５とインタークーラ１６との間の位置）には、コンプレッサ下流圧力検出装置２４Ｂが設けられている。コンプレッサ下流圧力検出装置２４Ｂは、例えば、圧力センサであり、コンプレッサ３５の下流側となる吸気管１１Ｂ内の圧力に応じた検出信号を制御装置５０に出力する。 A compressor upstream pressure detection device 24A is provided in the intake pipe 11A on the upstream side of the compressor 35. The compressor upstream pressure detection device 24A is, for example, a pressure sensor, and outputs a detection signal corresponding to the pressure in the intake pipe 11A on the upstream side of the compressor 35 to the control device 50. A compressor downstream pressure detection device 24B is provided in the intake pipe 11B (position between the compressor 35 and the intercooler 16 in the intake pipe 11B) on the downstream side of the compressor 35. The compressor downstream pressure detection device 24B is, for example, a pressure sensor, and outputs a detection signal corresponding to the pressure in the intake pipe 11B on the downstream side of the compressor 35 to the control device 50.
　吸気管１１Ｂには、上流側にインタークーラ１６が配置され、インタークーラ１６よりも下流側にスロットル装置４７が配置されている。インタークーラ１６は、コンプレッサ下流圧力検出装置２４Ｂよりも下流側に配置されており、コンプレッサ３５にて過給された吸気の温度を下げる。インタークーラ１６とスロットル装置４７との間には、吸気温度検出装置２８Ｂ（例えば、吸気温度センサ）が設けられている。吸気温度検出装置２８Ｂは、インタークーラ１６にて温度が低下された吸気の温度に応じた検出信号を制御装置５０に出力する。 In the intake pipe 11B, the intercooler 16 is arranged on the upstream side, and the throttle device 47 is arranged on the downstream side of the intercooler 16. The intercooler 16 is arranged on the downstream side of the compressor downstream pressure detection device 24B, and lowers the temperature of the intake air supercharged by the compressor 35. An intake air temperature detection device 28B (for example, an intake air temperature sensor) is provided between the intercooler 16 and the throttle device 47. The intake air temperature detection device 28B outputs a detection signal corresponding to the temperature of the intake air whose temperature has been lowered by the intercooler 16 to the control device 50.
　スロットル装置４７は、制御装置５０からの制御信号に基づいて吸気管１１Ｂの開度を調整するスロットルバルブ４７Ａを駆動し、吸気流量を調整可能である。制御装置５０は、スロットル開度検出装置４７Ｓ（例えば、スロットル開度センサ）からの検出信号と目標スロットル開度に基づいて、スロットル装置４７に制御信号を出力して吸気管１１Ｂに設けられたスロットルバルブ４７Ａの開度を調整可能である。制御装置５０は、アクセルペダル踏込量検出装置２５からの検出信号に基づいて検出したアクセルペダルの踏込量と内燃機関１０の運転状態とに基づいて目標スロットル開度を求める。 The throttle device 47 drives the throttle valve 47A that adjusts the opening degree of the intake pipe 11B based on the control signal from the control device 50, and the intake flow rate can be adjusted. The control device 50 outputs a control signal to the throttle device 47 based on the detection signal from the throttle opening detection device 47S (for example, the throttle opening sensor) and the target throttle opening, and the throttle provided in the intake pipe 11B. The opening degree of the valve 47A can be adjusted. The control device 50 obtains a target throttle opening degree based on the accelerator pedal depression amount detected based on the detection signal from the accelerator pedal depression amount detection device 25 and the operating state of the internal combustion engine 10.
　アクセルペダル踏込量検出装置２５は、例えば、アクセルペダル踏込角度センサであり、アクセルペダルに設けられている。制御装置５０は、アクセルペダル踏込量検出装置２５からの検出信号に基づいて、運転者によるアクセルペダルの踏込量を検出することが可能である。 The accelerator pedal depression amount detection device 25 is, for example, an accelerator pedal depression angle sensor, and is provided on the accelerator pedal. The control device 50 can detect the amount of depression of the accelerator pedal by the driver based on the detection signal from the accelerator pedal depression amount detection device 25.
　吸気管１１Ｂにおけるスロットル装置４７よりも下流側には、圧力検出装置２４Ｃが設けられており、ＥＧＲ配管１３の流出側が接続されている。そして、吸気管１１Ｂの流出側は吸気マニホールド１１Ｃの流入側に接続されており、吸気マニホールド１１Ｃの流出側は内燃機関１０の流入側に接続されている。圧力検出装置２４Ｃは、例えば、圧力センサであり、吸気マニホールド１１Ｃに流入する直前の吸気の圧力に応じた検出信号を制御装置５０に出力する。また、ＥＧＲ配管１３の流出側（吸気管１１Ｂとの接続部）からは、ＥＧＲ配管１３の流入側（排気管１２Ｂとの接続部）から流入してきたＥＧＲガスが、吸気管１１Ｂ内に吐出される。尚、ＥＧＲ配管１３にて形成されるＥＧＲガスが流れる経路は、ＥＧＲ経路に相当する。 A pressure detection device 24C is provided on the downstream side of the throttle device 47 in the intake pipe 11B, and the outflow side of the EGR pipe 13 is connected to the pressure detection device 24C. The outflow side of the intake pipe 11B is connected to the inflow side of the intake manifold 11C, and the outflow side of the intake manifold 11C is connected to the inflow side of the internal combustion engine 10. The pressure detection device 24C is, for example, a pressure sensor, and outputs a detection signal corresponding to the pressure of the intake air immediately before flowing into the intake manifold 11C to the control device 50. Further, from the outflow side (connection portion with the intake pipe 11B) of the EGR pipe 13, the EGR gas flowing in from the inflow side (connection portion with the exhaust pipe 12B) of the EGR pipe 13 is discharged into the intake pipe 11B. To. The path through which the EGR gas formed in the EGR pipe 13 flows corresponds to the EGR path.
　内燃機関１０は複数のシリンダ４５Ａ～４５Ｄを有しており、燃料噴射弁４３Ａ～４３Ｄが、それぞれのシリンダ４５Ａ～４５Ｄに設けられている。燃料噴射弁４３Ａ～４３Ｄには、コモンレール４１と燃料配管４２Ａ～４２Ｄを介して燃料が供給されており、燃料噴射弁４３Ａ～４３Ｄは、制御装置５０からの制御信号によって駆動され、それぞれのシリンダ４５Ａ～４５Ｄ内に燃料を噴射する。 The internal combustion engine 10 has a plurality of cylinders 45A to 45D, and fuel injection valves 43A to 43D are provided in the respective cylinders 45A to 45D. Fuel is supplied to the fuel injection valves 43A to 43D via the common rail 41 and the fuel pipes 42A to 42D. The fuel injection valves 43A to 43D are driven by a control signal from the control device 50, and the respective cylinders 45A. Fuel is injected within ~ 45D.
　また、各シリンダ４５Ａ～４５Ｄには、副噴射弁６３Ａ～６３Ｄ（冷却媒体供給装置）が設けられている。副噴射弁６３Ａ～６３Ｄには、水供給用コモンレール６１と水配管６２Ａ～６２Ｄを介して水（非燃焼液体）が供給されており、副噴射弁６３Ａ～６３Ｄは、制御装置５０からの制御信号によって駆動され、それぞれのシリンダ４５Ａ～４５Ｄ内に水を噴射する。 Further, each cylinder 45A to 45D is provided with auxiliary injection valves 63A to 63D (cooling medium supply device). Water (non-combustion liquid) is supplied to the sub-injection valves 63A to 63D via the water supply common rail 61 and the water pipes 62A to 62D, and the sub-injection valves 63A to 63D are control signals from the control device 50. Driven by, water is injected into the respective cylinders 45A-45D.
　水供給用コモンレール６１は、供給管６５、水ポンプ（液体供給装置）６６を介して、内燃機関１０に対して離間して配置された水タンク（液体タンク）６７に連結される。水ポンプ６６は、制御装置５０からの駆動信号により回転駆動される電動ポンプであり、正逆いずれの方向にも回転が可能となっている。水ポンプ６６の正回転により水タンク６７内の水（非燃焼液体）６８の吸い上げが行われ、水６８が供給管６５を介して水供給用コモンレール６１に供給される。また、水ポンプ６６の逆回転により水供給用コモンレール６１及び供給管６５内の水６８が吸い戻され、水タンク６７内に流入される。尚、供給管６５には、供給管６５内の水６８の圧力を検出する水圧センサを設けてもよい。 The water supply common rail 61 is connected to a water tank (liquid tank) 67 arranged apart from the internal combustion engine 10 via a supply pipe 65 and a water pump (liquid supply device) 66. The water pump 66 is an electric pump that is rotationally driven by a drive signal from the control device 50, and can rotate in either the forward or reverse direction. The forward rotation of the water pump 66 sucks up the water (non-combustion liquid) 68 in the water tank 67, and the water 68 is supplied to the water supply common rail 61 via the supply pipe 65. Further, the water 68 in the water supply common rail 61 and the supply pipe 65 is sucked back by the reverse rotation of the water pump 66 and flows into the water tank 67. The supply pipe 65 may be provided with a water pressure sensor that detects the pressure of the water 68 in the supply pipe 65.
　水タンク６７内には、水タンク６７内に貯留されている水６８の残量（水位）を検出するレベルゲージ（残量検出装置）６９が設けられている。レベルゲージ（残量検出装置）６９は、水タンク６７内の水６８が満タンから減少した残量に応じた信号（例えば、レベル１０～レベル１に相当する信号である。）を制御装置（ＥＣＵ）５０に出力する。 A level gauge (remaining amount detecting device) 69 for detecting the remaining amount (water level) of the water 68 stored in the water tank 67 is provided in the water tank 67. The level gauge (remaining amount detecting device) 69 controls a signal (for example, a signal corresponding to level 10 to level 1) according to the remaining amount of water 68 in the water tank 67 reduced from full. Output to ECU) 50.
　内燃機関１０には、回転検出装置２２、クーラント温度検出装置２８Ｃ等が設けられている。回転検出装置２２は、例えば、回転センサであり、内燃機関１０のクランクシャフトの回転角（すなわち、クランク角度）に応じた検出信号を制御装置５０に出力する。例えば、回転検出装置２２は、クランクシャフトが１５度回転する毎に出力パルスを発生し、この出力パルスが制御装置５０に入力される。制御装置５０は、回転検出装置２２の出力パルスからクランク角度、及び、エンジン回転数を算出する。クーラント温度検出装置２８Ｃは、例えば、温度センサであり、内燃機関１０内に循環されている冷却用クーラントの温度を検出し、検出した温度に応じた検出信号を制御装置５０に出力する。 The internal combustion engine 10 is provided with a rotation detection device 22, a coolant temperature detection device 28C, and the like. The rotation detection device 22 is, for example, a rotation sensor, and outputs a detection signal corresponding to the rotation angle (that is, the crank angle) of the crankshaft of the internal combustion engine 10 to the control device 50. For example, the rotation detection device 22 generates an output pulse every time the crankshaft rotates 15 degrees, and this output pulse is input to the control device 50. The control device 50 calculates the crank angle and the engine speed from the output pulse of the rotation detection device 22. The coolant temperature detection device 28C is, for example, a temperature sensor, detects the temperature of the cooling coolant circulating in the internal combustion engine 10, and outputs a detection signal corresponding to the detected temperature to the control device 50.
　内燃機関１０の排気側には排気マニホールド１２Ａの流入側が接続され、排気マニホールド１２Ａの流出側には排気管１２Ｂの流入側が接続されている。排気管１２Ｂの流出側はタービン３６の流入側に接続され、タービン３６の流出側は排気管１２Ｃの流入側に接続されている。 The inflow side of the exhaust manifold 12A is connected to the exhaust side of the internal combustion engine 10, and the inflow side of the exhaust pipe 12B is connected to the outflow side of the exhaust manifold 12A. The outflow side of the exhaust pipe 12B is connected to the inflow side of the turbine 36, and the outflow side of the turbine 36 is connected to the inflow side of the exhaust pipe 12C.
　排気管１２Ｂには、ＥＧＲ配管１３の流入側が接続されている。ＥＧＲ配管１３は、排気管１２Ｂと吸気管１１Ｂとを連通し、排気管１２Ｂ（排気経路に相当）の排気ガスの一部を吸気管１１Ｂ（吸気経路に相当）に還流させることが可能である。また、ＥＧＲ配管１３には、経路切替装置１４Ａ、バイパス配管１３Ｂ、ＥＧＲクーラ１５、ＥＧＲ弁１４Ｂが設けられている。 The inflow side of the EGR pipe 13 is connected to the exhaust pipe 12B. The EGR pipe 13 communicates the exhaust pipe 12B and the intake pipe 11B, and can recirculate a part of the exhaust gas of the exhaust pipe 12B (corresponding to the exhaust path) to the intake pipe 11B (corresponding to the intake path). .. Further, the EGR pipe 13 is provided with a route switching device 14A, a bypass pipe 13B, an EGR cooler 15, and an EGR valve 14B.
　経路切替装置１４Ａは、排気管１２ＢからＥＧＲ配管１３へと流れてきたＥＧＲガスを、ＥＧＲクーラ１５を経由させて吸気経路に戻すＥＧＲクーラ経路と、バイパス配管１３ＢにてＥＧＲクーラ１５をバイパスさせて吸気管１１Ｂに戻すバイパス経路とを、制御装置５０からの制御信号に基づいて切り替える経路切替弁である。バイパス配管１３Ｂは、ＥＧＲクーラ１５をバイパスするように設けられており、流入側は経路切替装置１４Ａに接続され、流出側はＥＧＲ弁１４ＢとＥＧＲクーラ１５の間となるＥＧＲ配管１３に接続されている。 The route switching device 14A bypasses the EGR cooler 15 in the bypass pipe 13B and the EGR cooler path that returns the EGR gas flowing from the exhaust pipe 12B to the EGR pipe 13 to the intake path via the EGR cooler 15. It is a path switching valve that switches the bypass path back to the intake pipe 11B based on the control signal from the control device 50. The bypass pipe 13B is provided so as to bypass the EGR cooler 15, the inflow side is connected to the route switching device 14A, and the outflow side is connected to the EGR pipe 13 between the EGR valve 14B and the EGR cooler 15. There is.
　ＥＧＲ弁１４Ｂ（ＥＧＲバルブ）は、ＥＧＲ配管１３におけるＥＧＲクーラ１５の下流側、かつ、ＥＧＲ配管１３とバイパス配管１３Ｂとの合流部の下流側、に設けられている。そして、ＥＧＲ弁１４Ｂは、制御装置５０からの制御信号に基づいて、ＥＧＲ配管１３の開度を調整することで、ＥＧＲ配管１３内を流れるＥＧＲガスの流量を調整する。 The EGR valve 14B (EGR valve) is provided on the downstream side of the EGR cooler 15 in the EGR pipe 13 and on the downstream side of the confluence portion between the EGR pipe 13 and the bypass pipe 13B. Then, the EGR valve 14B adjusts the flow rate of the EGR gas flowing in the EGR pipe 13 by adjusting the opening degree of the EGR pipe 13 based on the control signal from the control device 50.
　ＥＧＲクーラ１５は、ＥＧＲ配管１３とバイパス配管１３Ｂとの合流部と、経路切替装置１４Ａとの間となるＥＧＲ配管１３に設けられている。ＥＧＲクーラ１５は、いわゆる熱交換器であり、冷却用のクーラントが供給され、流入されたＥＧＲガスを冷却して吐出する。 The EGR cooler 15 is provided in the EGR pipe 13 between the confluence of the EGR pipe 13 and the bypass pipe 13B and the route switching device 14A. The EGR cooler 15 is a so-called heat exchanger, and a coolant for cooling is supplied to cool the inflowed EGR gas and discharge it.
　排気管１２Ｂには、排気温度検出装置２９が設けられている。排気温度検出装置２９は、例えば、排気温度センサであり、排気温度に応じた検出信号を制御装置５０に出力する。制御装置５０は、排気温度検出装置２９を用いて検出した排気温度とＥＧＲ弁１４Ｂの制御状態と内燃機関１０の運転状態等に基づいて、ＥＧＲ配管１３及びＥＧＲクーラ１５（またはバイパス配管１３Ｂ）及びＥＧＲ弁１４Ｂを経由して吸気管１１Ｂに流入されるＥＧＲガスの温度を推定可能である。 The exhaust pipe 12B is provided with an exhaust temperature detection device 29. The exhaust temperature detection device 29 is, for example, an exhaust temperature sensor, and outputs a detection signal corresponding to the exhaust temperature to the control device 50. The control device 50 has the EGR pipe 13 and the EGR cooler 15 (or bypass pipe 13B) and the EGR cooler 15 (or bypass pipe 13B) based on the exhaust temperature detected by the exhaust temperature detection device 29, the control state of the EGR valve 14B, the operating state of the internal combustion engine 10, and the like. The temperature of the EGR gas flowing into the intake pipe 11B via the EGR valve 14B can be estimated.
　排気管１２Ｂの流出側は、タービン３６の流入側に接続され、タービン３６の流出側は、排気管１２Ｃの流入側に接続されている。タービン３６には、タービンインペラ３６Ａへ導く排気ガスの流速を制御可能な可変ノズル３３が設けられており、可変ノズル３３は、ノズル駆動装置３１によって開度が調整される。制御装置５０は、ノズル開度検出装置３２（例えば、ノズル開度センサ）からの検出信号と目標ノズル開度に基づいて、ノズル駆動装置３１に制御信号を出力して可変ノズル３３の開度を調整可能である。 The outflow side of the exhaust pipe 12B is connected to the inflow side of the turbine 36, and the outflow side of the turbine 36 is connected to the inflow side of the exhaust pipe 12C. The turbine 36 is provided with a variable nozzle 33 capable of controlling the flow velocity of the exhaust gas leading to the turbine impeller 36A, and the opening degree of the variable nozzle 33 is adjusted by the nozzle driving device 31. The control device 50 outputs a control signal to the nozzle drive device 31 based on the detection signal from the nozzle opening detection device 32 (for example, the nozzle opening sensor) and the target nozzle opening to determine the opening of the variable nozzle 33. It is adjustable.
　タービン３６の上流側となる排気管１２Ｂには、タービン上流圧力検出装置２６Ａが設けられている。タービン上流圧力検出装置２６Ａは、例えば圧力センサであり、タービン３６の上流側となる排気管１２Ｂ内の圧力に応じた検出信号を制御装置５０に出力する。タービン３６の下流側となる排気管１２Ｃには、タービン下流圧力検出装置２６Ｂが設けられている。タービン下流圧力検出装置２６Ｂは、例えば圧力センサであり、タービン３６の下流側となる排気管１２Ｃ内の圧力に応じた検出信号を制御装置５０に出力する。 The turbine upstream pressure detection device 26A is provided in the exhaust pipe 12B on the upstream side of the turbine 36. The turbine upstream pressure detection device 26A is, for example, a pressure sensor, and outputs a detection signal corresponding to the pressure in the exhaust pipe 12B on the upstream side of the turbine 36 to the control device 50. A turbine downstream pressure detecting device 26B is provided in the exhaust pipe 12C on the downstream side of the turbine 36. The turbine downstream pressure detection device 26B is, for example, a pressure sensor, and outputs a detection signal corresponding to the pressure in the exhaust pipe 12C on the downstream side of the turbine 36 to the control device 50.
　排気管１２Ｃの流出側には不図示の排気ガス浄化装置が接続されている。例えば、内燃機関１０がディーゼルエンジンの場合、排気ガス浄化装置には、酸化触媒、微粒子捕集フィルタ、選択還元触媒等が含まれている。 An exhaust gas purification device (not shown) is connected to the outflow side of the exhaust pipe 12C. For example, when the internal combustion engine 10 is a diesel engine, the exhaust gas purification device includes an oxidation catalyst, a particulate filter, a selective reduction catalyst, and the like.
　制御装置（ＥＣＵ：Electronic Control Unit）５０は、少なくとも、プロセッサ５１（ＣＰＵ、ＭＰＵ（Micro-Processing Unit）等）、記憶装置５３（ＤＲＡＭ、ＲＯＭ、ＥＥＰＲＯＭ、ＳＲＡＭ、ハードディスク等）を有している。制御装置５０（ＥＣＵ）は、図１に示す検出装置やアクチュエータに限定されず、上記の検出装置を含めた各種の検出装置からの検出信号に基づいて内燃機関１０の運転状態を検出し、上記の燃料噴射弁４３Ａ～４３Ｄ、副噴射弁６３Ａ～６３Ｄ、ＥＧＲ弁１４Ｂ、経路切替装置１４Ａ、ノズル駆動装置３１、スロットル装置４７を含めた各種のアクチュエータを制御する。記憶装置５３は、例えば、各種処理を実行するためのプログラムやパラメータ等を記憶する。 The control device (ECU: Electronic Control Unit) 50 has at least a processor 51 (CPU, MPU (Micro-Processing Unit), etc.) and a storage device 53 (DRAM, ROM, EEPROM, SRAM, hard disk, etc.). The control device 50 (ECU) is not limited to the detection device and the actuator shown in FIG. 1, and detects the operating state of the internal combustion engine 10 based on the detection signals from various detection devices including the above-mentioned detection device. Controls various actuators including the fuel injection valves 43A to 43D, the auxiliary injection valves 63A to 63D, the EGR valve 14B, the path switching device 14A, the nozzle drive device 31, and the throttle device 47. The storage device 53 stores, for example, programs, parameters, and the like for executing various processes.
　大気圧検出装置２３は、例えば、大気圧センサであり、制御装置５０に設けられている。大気圧検出装置２３は、制御装置５０の周囲の大気圧に応じた検出信号を制御装置５０に出力する。車速検出装置２７は、例えば、車両速度検出センサであり、車両の車輪等に設けられている。車速検出装置２７は、車両の車輪の回転速度に応じた検出信号を制御装置５０に出力する。 The atmospheric pressure detection device 23 is, for example, an atmospheric pressure sensor and is provided in the control device 50. The atmospheric pressure detection device 23 outputs a detection signal corresponding to the atmospheric pressure around the control device 50 to the control device 50. The vehicle speed detection device 27 is, for example, a vehicle speed detection sensor, which is provided on the wheels of the vehicle or the like. The vehicle speed detection device 27 outputs a detection signal according to the rotation speed of the wheels of the vehicle to the control device 50.
　次に、燃料噴射弁４３Ａ～４３Ｄ、及び、副噴射弁６３Ａ～６３Ｄの取付構造について図２に基づいて説明する。尚、燃料噴射弁４３Ａ～４３Ｄ、及び、副噴射弁６３Ａ～６３Ｄの取付構造は、ほぼ同じ取付構造であるので、燃料噴射弁４３Ａ及び副噴射弁６３Ａの取付構造について説明する。 Next, the mounting structures of the fuel injection valves 43A to 43D and the sub-injection valves 63A to 63D will be described with reference to FIG. Since the mounting structures of the fuel injection valves 43A to 43D and the sub-injection valves 63A to 63D are almost the same mounting structures, the mounting structures of the fuel injection valves 43A and the sub-injection valves 63A will be described.
　図２に示すように、内燃機関１０は、シリンダ４５Ａ等が形成されたシリンダブロック７１と、シリンダヘッド７２とを備えている。シリンダ４５Ａ内には、シリンダ４５Ａ内を往復運動するピストン７３が配置されている。ピストン７３とシリンダヘッド７２の間のシリンダ４５Ａ内には混合気が燃焼する燃焼室７５が形成されている。ピストン７３の頂面には凹状に形成されたキャビティ７６が形成されている。 As shown in FIG. 2, the internal combustion engine 10 includes a cylinder block 71 in which a cylinder 45A or the like is formed, and a cylinder head 72. A piston 73 that reciprocates in the cylinder 45A is arranged in the cylinder 45A. A combustion chamber 75 through which the air-fuel mixture burns is formed in the cylinder 45A between the piston 73 and the cylinder head 72. A concave cavity 76 is formed on the top surface of the piston 73.
　燃料噴射弁４３Ａは、燃焼室７５の上壁面の中央に配置されており、燃料噴射弁４３Ａからはピストン７３に形成されたキャビティ７６内の周辺部に向けて燃料Ｆが直接噴射されるように構成されている（図２の右図参照）。副噴射弁６３Ａは、燃焼室７５の上壁面の周辺部に、燃料噴射弁４３Ａに対して斜めに傾斜して配置されており、副噴射弁６３Ａからは、燃料噴射弁４３Ａの複数（例えば、８個）の燃料噴射口４９（図７及び図８参照）の周囲の所定領域ＦＬに燃料Ｆよりも着火性の劣る液体である水６８を噴射（供給）するように構成されている（図２の左図参照）。これにより、燃料噴射弁４３Ａの複数の燃料噴射口４９（図７及び図８参照）の周囲の所定領域ＦＬが、水６８の気化熱によって燃料Ｆの着火温度よりも低い温度に冷却される。 The fuel injection valve 43A is arranged in the center of the upper wall surface of the combustion chamber 75 so that the fuel F is directly injected from the fuel injection valve 43A toward the peripheral portion in the cavity 76 formed in the piston 73. It is configured (see the right figure in FIG. 2). The sub-injection valve 63A is arranged in the peripheral portion of the upper wall surface of the combustion chamber 75 at an angle with respect to the fuel injection valve 43A, and from the sub-injection valve 63A, a plurality of fuel injection valves 43A (for example, for example). It is configured to inject (supply) water 68, which is a liquid inferior in ignitability to fuel F, to a predetermined region FL around the fuel injection ports 49 (see FIGS. 7 and 8) of (8). See the left figure of 2). As a result, the predetermined region FL around the plurality of fuel injection ports 49 (see FIGS. 7 and 8) of the fuel injection valve 43A is cooled to a temperature lower than the ignition temperature of the fuel F by the heat of vaporization of the water 68.
　次に、上記のように構成された内燃機関１０における、制御装置５０による燃料噴射弁４３Ａ～４３Ｄが燃料Ｆの主噴射を行う前に、副噴射弁６３Ａ～６３Ｄによって水６８（図２参照）を噴射する水噴射制御処理の一例について図３乃至図８に基づいて説明する。尚、制御装置５０は、内燃機関１０の運転中に、所定時間間隔（例えば、数１０ｍｓｅｃ～数１００ｍｓｅｃ間隔）にて、図３及び図４のフローチャートに示される処理手順を繰り返し実行する。 Next, in the internal combustion engine 10 configured as described above, before the fuel injection valves 43A to 43D by the control device 50 perform the main injection of the fuel F, the sub-injection valves 63A to 63D make water 68 (see FIG. 2). An example of the water injection control process for injecting the fuel will be described with reference to FIGS. 3 to 8. During the operation of the internal combustion engine 10, the control device 50 repeatedly executes the processing procedure shown in the flowcharts of FIGS. 3 and 4 at predetermined time intervals (for example, at intervals of several tens of msec to several 100 msec).
　図３及び図４に示すように、先ず、ステップＳ１１において、制御装置５０は、アクセルペダル踏込量検出装置２５、回転検出装置２２、及びクーラント温度検出装置２８Ｃ等の各検出値に基づいてアクセルペダルの踏込量（要求負荷）、エンジン回転数ＮＥ、クランク角度、及び、冷却用クーラントの温度等を算出して、ＲＡＭに記憶した後、ステップＳ１２に進む。 As shown in FIGS. 3 and 4, first, in step S11, the control device 50 uses the accelerator pedal based on the detection values of the accelerator pedal depression amount detection device 25, the rotation detection device 22, the coolant temperature detection device 28C, and the like. The stepping amount (required load), engine speed NE, crank angle, temperature of the cooling coolant, and the like are calculated and stored in the RAM, and then the process proceeds to step S12.
　ステップＳ１２において、制御装置５０は、燃料噴射フラグをＲＡＭから読み出し、「ＯＮ」に設定されているか否か、つまり、今回の第１プレ噴射Ｊ１と第２プレ噴射Ｊ２と主噴射ＪＭ１（図５参照）のそれぞれの燃料噴射量及び燃料噴射開始時期が設定されているか否かを判定する。尚、燃料噴射フラグは、制御装置５０の起動時に、「ＯＦＦ」に設定されてＲＡＭに記憶される。そして、燃料噴射フラグが「ＯＮ」に設定されていると判定した場合には（Ｓ１２：ＹＥＳ）、制御装置５０は、後述のステップＳ２２に進む。 In step S12, the control device 50 reads the fuel injection flag from the RAM and determines whether or not it is set to "ON", that is, the first pre-injection J1, the second pre-injection J2, and the main injection JM1 (FIG. 5). (Refer to), it is determined whether or not each fuel injection amount and fuel injection start time are set. The fuel injection flag is set to "OFF" and stored in the RAM when the control device 50 is started. Then, when it is determined that the fuel injection flag is set to "ON" (S12: YES), the control device 50 proceeds to step S22, which will be described later.
　一方、燃料噴射フラグが「ＯＦＦ」に設定されていると判定した場合には（Ｓ１２：ＮＯ）、制御装置５０は、ステップＳ１３に進む。ステップＳ１３において、制御装置５０は、ステップＳ１１で取得した要求負荷及びエンジン回転数ＮＥに基づいて今回の第１プレ噴射Ｊ１と第２プレ噴射Ｊ２のそれぞれの燃料噴射量Ｑ２と、主噴射ＪＭ１の燃料噴射量Ｑ３とを取得して、ＲＡＭに記憶した後、ステップＳ１４に進む。 On the other hand, if it is determined that the fuel injection flag is set to "OFF" (S12: NO), the control device 50 proceeds to step S13. In step S13, the control device 50 determines the fuel injection amounts Q2 of the first pre-injection J1 and the second pre-injection J2, and the main injection JM1 based on the required load and the engine speed NE acquired in step S11. After acquiring the fuel injection amount Q3 and storing it in the RAM, the process proceeds to step S14.
　例えば、要求負荷及びエンジン回転数ＮＥに対する最適な第１プレ噴射Ｊ１と第２プレ噴射Ｊ２のそれぞれの燃料噴射量Ｑ２と、主噴射ＪＭ１の燃料噴射量Ｑ３とを予め試験により取得しておき、要求負荷及びエンジン回転数ＮＥと各燃料噴射量Ｑ２、Ｑ３との関係をマップ等に記憶させておく。そして、制御装置５０は、当該マップを参照して各燃料噴射量Ｑ２、Ｑ３を算出すればよい。また、冷却用クーラントの温度の検出値に基づいて各燃料噴射量Ｑ２、Ｑ３を温度補正するようにしてもよい。 For example, the optimum fuel injection amounts Q2 of the first pre-injection J1 and the second pre-injection J2 for the required load and the engine speed NE, and the fuel injection amount Q3 of the main injection JM1 are obtained in advance by a test. The relationship between the required load and engine speed NE and each fuel injection amount Q2 and Q3 is stored in a map or the like. Then, the control device 50 may calculate each fuel injection amount Q2 and Q3 with reference to the map. Further, the temperature of each fuel injection amount Q2 and Q3 may be corrected based on the detected value of the temperature of the cooling coolant.
　ステップＳ１４において、制御装置５０は、ステップＳ１１で取得した要求負荷及びエンジン回転数ＮＥに基づいて第１プレ噴射Ｊ１と、第２プレ噴射Ｊ２と、主噴射ＪＭ１のそれぞれの燃料噴射開始時期を取得して、ＲＡＭに記憶した後、ステップＳ１５に進む。 In step S14, the control device 50 acquires the fuel injection start timings of the first pre-injection J1, the second pre-injection J2, and the main injection JM1 based on the required load and the engine speed NE acquired in step S11. Then, after storing in the RAM, the process proceeds to step S15.
　例えば、要求負荷及びエンジン回転数ＮＥに対する最適な第１プレ噴射Ｊ１と、第２プレ噴射Ｊ２と、主噴射ＪＭ１のそれぞれの燃料噴射開始時期を予め試験により取得しておき、要求負荷及びエンジン回転数ＮＥと各燃料噴射開始時期との関係をマップ等に記憶させておく。そして、制御装置５０は、当該マップを参照して第１プレ噴射Ｊ１と、第２プレ噴射Ｊ２と、主噴射ＪＭ１のそれぞれの燃料噴射開始時期を算出すればよい。また、冷却用クーラントの温度の検出値に基づいて、第１プレ噴射Ｊ１と、第２プレ噴射Ｊ２と、主噴射ＪＭ１のそれぞれの燃料噴射開始時期を温度補正するようにしてもよい。 For example, the optimum fuel injection start timings of the first pre-injection J1, the second pre-injection J2, and the main injection JM1 for the required load and the engine rotation speed NE are acquired in advance by a test, and the required load and the engine rotation are obtained. The relationship between the number NE and each fuel injection start time is stored in a map or the like. Then, the control device 50 may calculate the fuel injection start timing of each of the first pre-injection J1, the second pre-injection J2, and the main injection JM1 with reference to the map. Further, the fuel injection start timings of the first pre-injection J1, the second pre-injection J2, and the main injection JM1 may be temperature-corrected based on the detected value of the temperature of the cooling coolant.
　例えば、図５に示すように、主噴射ＪＭ１の燃料噴射開始時期は、例えば、圧縮上死点ＴＤＣで燃料噴射弁４３Ａ～４３Ｄの各燃料噴射口４９からの燃料噴射量が最大値に達するように設定される。そして、第１プレ噴射Ｊ１と第２プレ噴射Ｊ２の燃料噴射開始時期は、主噴射ＪＭ１の開始前に第１プレ噴射Ｊ１及び第２プレ噴射Ｊ２によって噴射された燃料の燃焼による熱発生が全くないか又はほとんどないように設定される。 For example, as shown in FIG. 5, the fuel injection start timing of the main injection JM1 is such that the fuel injection amount from each fuel injection port 49 of the fuel injection valves 43A to 43D reaches the maximum value at the compression top dead center TDC, for example. Is set to. Then, at the fuel injection start timing of the first pre-injection J1 and the second pre-injection J2, heat generation due to the combustion of the fuel injected by the first pre-injection J1 and the second pre-injection J2 before the start of the main injection JM1 is completely generated. Set to absent or almost absent.
　一方、従来の主噴射ＪＭ２の燃料噴射開始時期は、圧縮上死点ＴＤＣ以降で燃料噴射弁４３Ａ～４３Ｄの各燃料噴射口４９からの燃料噴射量が最大値に達するように設定されている。従って、主噴射ＪＭ１の燃料噴射開始時期は、従来の主噴射ＪＭ２の燃料噴射開始時期よりも時間Ｔ１だけ早くなるように設定されている。 On the other hand, the fuel injection start timing of the conventional main injection JM2 is set so that the fuel injection amount from each fuel injection port 49 of the fuel injection valves 43A to 43D reaches the maximum value after the compression top dead center TDC. Therefore, the fuel injection start timing of the main injection JM1 is set to be earlier than the fuel injection start timing of the conventional main injection JM2 by the time T1.
　ステップＳ１５において、制御装置５０は、ＲＡＭから燃料噴射フラグを読み出し、「ＯＮ」に設定して、再度ＲＡＭに記憶した後、ステップＳ１６に進む。ステップＳ１６において、制御装置５０は、今回の第１プレ噴射Ｊ１と第２プレ噴射Ｊ２のそれぞれの燃料噴射量Ｑ２と、主噴射ＪＭ１の燃料噴射量Ｑ３とをＲＡＭから読み出し、これらを合計して総燃料噴射量を算出してＲＡＭに記憶する。そして、制御装置５０は、総燃料噴射量が所定の燃料噴射量閾値Ｑ１以上であるか否かを判定する。尚、燃料噴射量閾値Ｑ１は、予め記憶装置５３を構成するＲＯＭ又はＥＥＰＲＯＭ等に記憶されている。 In step S15, the control device 50 reads the fuel injection flag from the RAM, sets it to "ON", stores it in the RAM again, and then proceeds to step S16. In step S16, the control device 50 reads out the fuel injection amount Q2 of each of the first pre-injection J1 and the second pre-injection J2 and the fuel injection amount Q3 of the main injection JM1 from the RAM, and totals them. The total fuel injection amount is calculated and stored in the RAM. Then, the control device 50 determines whether or not the total fuel injection amount is equal to or higher than the predetermined fuel injection amount threshold value Q1. The fuel injection amount threshold value Q1 is stored in advance in a ROM, EEPROM, or the like that constitutes the storage device 53.
　そして、総燃料噴射量が所定の燃料噴射量閾値Ｑ１未満であると判定した場合には（Ｓ１６：ＮＯ）、制御装置５０は、ステップＳ１７に進む。ステップＳ１７において、制御装置５０は、水噴射フラグをＲＡＭから読み出し、「ＯＦＦ」に設定して、再度ＲＡＭに記憶した後、後述のステップＳ２２に進む。尚、水噴射フラグは、制御装置５０の起動時に、「ＯＦＦ」に設定されてＲＡＭに記憶される。 Then, when it is determined that the total fuel injection amount is less than the predetermined fuel injection amount threshold value Q1 (S16: NO), the control device 50 proceeds to step S17. In step S17, the control device 50 reads the water injection flag from the RAM, sets it to “OFF”, stores it in the RAM again, and then proceeds to step S22 described later. The water injection flag is set to "OFF" and stored in the RAM when the control device 50 is started.
　一方、総燃料噴射量が所定の燃料噴射量閾値Ｑ１以上であると判定した場合には（Ｓ１６：ＹＥＳ）、制御装置５０は、ステップＳ１８に進む。ステップＳ１８において、制御装置５０は、副噴射弁６３Ａ～６３Ｄによる水噴射Ｋ１を行う条件が成立したか否かを判定する。例えば、冷却用クーラントの温度が所定温度よりも低く暖機運転中の場合や、要求トルクが所定トルク以下の場合等には、制御装置５０は、副噴射弁６３Ａ～６３Ｄによる水噴射Ｋ１を行う条件が成立していないと判定する。 On the other hand, when it is determined that the total fuel injection amount is equal to or higher than the predetermined fuel injection amount threshold value Q1 (S16: YES), the control device 50 proceeds to step S18. In step S18, the control device 50 determines whether or not the condition for performing the water injection K1 by the sub-injection valves 63A to 63D is satisfied. For example, when the temperature of the cooling coolant is lower than the predetermined temperature during warm-up operation, or when the required torque is equal to or less than the predetermined torque, the control device 50 performs water injection K1 by the sub-injection valves 63A to 63D. It is determined that the condition is not satisfied.
　そして、副噴射弁６３Ａ～６３Ｄによる水噴射Ｋ１を行う条件が成立していないと判定した場合には（Ｓ１８：ＮＯ）、制御装置５０は、前記ステップＳ１７以降の処理を実行する。一方、副噴射弁６３Ａ～６３Ｄによる水噴射Ｋ１を行う条件が成立したと判定した場合には（Ｓ１８：ＹＥＳ）、制御装置５０は、ステップＳ１９の処理に進む。ステップＳ１９において、制御装置５０は、ステップＳ１６で算出した総燃料噴射量をＲＡＭから読み出し、この総燃料噴射量に基づいて今回の水噴射Ｋ１（図５参照）の水噴射量Ｑ５を取得して、ＲＡＭに記憶した後、ステップＳ２０に進む。 Then, when it is determined that the condition for performing the water injection K1 by the sub-injection valves 63A to 63D is not satisfied (S18: NO), the control device 50 executes the processes after step S17. On the other hand, when it is determined that the condition for performing the water injection K1 by the sub-injection valves 63A to 63D is satisfied (S18: YES), the control device 50 proceeds to the process of step S19. In step S19, the control device 50 reads the total fuel injection amount calculated in step S16 from the RAM, and acquires the water injection amount Q5 of the current water injection K1 (see FIG. 5) based on the total fuel injection amount. , After storing in the RAM, the process proceeds to step S20.
　例えば、図６に示すように、燃料噴射弁４３Ａ～４３Ｄによって噴射される総燃料噴射量に対する副噴射弁６３Ａ～６３Ｄによる最適な水噴射Ｋ１の水噴射量Ｑ５を予め試験により取得しておき、総燃料噴射量と水噴射量Ｑ５との関係をマップＭ１に記憶させておく。そして、制御装置５０は、当該マップＭ１を参照して水噴射量Ｑ５を算出する。尚、水タンク６７に貯留される水６８の水温を水温センサ等により検出して、水噴射量Ｑ５を補正するようにしてもよい。 For example, as shown in FIG. 6, the optimum water injection amount Q5 of the water injection K1 by the sub-injection valves 63A to 63D with respect to the total fuel injection amount injected by the fuel injection valves 43A to 43D is obtained in advance by a test. The relationship between the total fuel injection amount and the water injection amount Q5 is stored in the map M1. Then, the control device 50 calculates the water injection amount Q5 with reference to the map M1. The water temperature of the water 68 stored in the water tank 67 may be detected by a water temperature sensor or the like to correct the water injection amount Q5.
　ステップＳ２０において、制御装置５０は、ステップＳ１４で取得した燃料Ｆの主噴射ＪＭ１の燃料噴射開始時期に基づいて、副噴射弁６３Ａ～６３Ｄによる水噴射Ｋ１の水噴射量Ｑ５に対する水噴射開始時期を取得して、ＲＡＭに記憶した後、ステップＳ２１に進む。 In step S20, the control device 50 sets the water injection start timing for the water injection amount Q5 of the water injection K1 by the sub-injection valves 63A to 63D based on the fuel injection start timing of the main injection JM1 of the fuel F acquired in step S14. After acquiring and storing in the RAM, the process proceeds to step S21.
　例えば、図５に示すように、第２プレ噴射Ｊ２の燃料を噴射した後で、且つ、主噴射ＪＭ１の燃料噴射開始時期の前に設定する最適な水噴射Ｋ１の水噴射量Ｑ５に対する水噴射開始時期を予め試験により取得しておき、主噴射ＪＭ１の燃料噴射開始時期と水噴射Ｋ１の水噴射量Ｑ５に対する水噴射開始時期との関係をマップ等に記憶させておく。そして、制御装置５０は、当該マップを参照して水噴射Ｋ１の水噴射量Ｑ５に対する水噴射開始時期を算出すればよい。尚、水噴射期間Ｔ２～Ｔ３は、主噴射ＪＭ１の燃料噴射開始時期（時間Ｔ４におけるクランク角度）よりも前に終了するように設定されている。 For example, as shown in FIG. 5, water injection with respect to the optimum water injection amount Q5 of the optimum water injection K1 set after the fuel of the second pre-injection J2 is injected and before the fuel injection start timing of the main injection JM1. The start time is acquired in advance by a test, and the relationship between the fuel injection start time of the main injection JM1 and the water injection start time with respect to the water injection amount Q5 of the water injection K1 is stored in a map or the like. Then, the control device 50 may calculate the water injection start timing with respect to the water injection amount Q5 of the water injection K1 with reference to the map. The water injection periods T2 to T3 are set to end before the fuel injection start time (crank angle at time T4) of the main injection JM1.
　ステップＳ２１において、制御装置５０は、ＲＡＭから水噴射フラグを読み出し、「ＯＮ」に設定して、再度ＲＡＭに記憶した後、ステップＳ２２に進む。尚、水噴射フラグは、制御装置５０の起動時に、「ＯＦＦ」に設定されてＲＡＭに記憶される。続いて、ステップＳ２２において、制御装置５０は、ステップＳ１１で取得したクランク角度と、ステップＳ１４で取得した第１プレ噴射Ｊ１の燃料噴射開始時期と、をＲＡＭから読み出し、当該クランク角度が第１プレ噴射Ｊ１の燃料噴射開始時期（図５参照）であるか否かを判定する。 In step S21, the control device 50 reads the water injection flag from the RAM, sets it to "ON", stores it in the RAM again, and then proceeds to step S22. The water injection flag is set to "OFF" and stored in the RAM when the control device 50 is started. Subsequently, in step S22, the control device 50 reads the crank angle acquired in step S11 and the fuel injection start timing of the first pre-injection J1 acquired in step S14 from the RAM, and the crank angle is the first pre-injection. It is determined whether or not it is the fuel injection start time (see FIG. 5) of the injection J1.
　そして、当該クランク角度が第１プレ噴射Ｊ１の燃料噴射開始時期であると判定した場合には（Ｓ２２：ＹＥＳ）、制御装置５０は、ステップＳ２３に進む。ステップＳ２３において、制御装置５０は、図５に示すように、ステップＳ１３で取得した第１プレ噴射Ｊ１の燃料噴射量Ｑ２となるように今回の燃料噴射弁（例えば、燃料噴射弁４３Ａ）の作動を制御する。そして、制御装置５０は、ステップＳ１３で取得した第１プレ噴射Ｊ１の燃料噴射量Ｑ２を噴射した後、当該処理を終了する。 Then, when it is determined that the crank angle is the fuel injection start time of the first pre-injection J1 (S22: YES), the control device 50 proceeds to step S23. In step S23, as shown in FIG. 5, the control device 50 operates the fuel injection valve (for example, the fuel injection valve 43A) this time so as to have the fuel injection amount Q2 of the first pre-injection J1 acquired in step S13. To control. Then, the control device 50 injects the fuel injection amount Q2 of the first pre-injection J1 acquired in step S13, and then ends the process.
　一方、当該クランク角度が第１プレ噴射Ｊ１の燃料噴射開始時期でないと判定した場合には（Ｓ２２：ＮＯ）、制御装置５０は、ステップＳ２４に進む。ステップＳ２４において、制御装置５０は、ステップＳ１１で取得したクランク角度と、ステップＳ１４で取得した第２プレ噴射Ｊ２の燃料噴射開始時期と、をＲＡＭから読み出し、当該クランク角度が第２プレ噴射Ｊ２の燃料噴射開始時期（図５参照）であるか否かを判定する。 On the other hand, if it is determined that the crank angle is not the fuel injection start time of the first pre-injection J1 (S22: NO), the control device 50 proceeds to step S24. In step S24, the control device 50 reads the crank angle acquired in step S11 and the fuel injection start timing of the second pre-injection J2 acquired in step S14 from the RAM, and the crank angle is the second pre-injection J2. It is determined whether or not it is the fuel injection start time (see FIG. 5).
　そして、当該クランク角度が第２プレ噴射Ｊ２の燃料噴射開始時期であると判定した場合には（Ｓ２４：ＹＥＳ）、制御装置５０は、前記ステップＳ２３に進む。ステップＳ２３において、制御装置５０は、図５に示すように、ステップＳ１３で取得した第２プレ噴射Ｊ２の燃料噴射量Ｑ２となるように今回の燃料噴射弁（例えば、燃料噴射弁４３Ａ）の作動を制御する。そして、制御装置５０は、ステップＳ１３で取得した第２プレ噴射Ｊ２の燃料噴射量Ｑ２を噴射した後、当該処理を終了する。 Then, when it is determined that the crank angle is the fuel injection start time of the second pre-injection J2 (S24: YES), the control device 50 proceeds to the step S23. In step S23, as shown in FIG. 5, the control device 50 operates the fuel injection valve (for example, the fuel injection valve 43A) this time so as to have the fuel injection amount Q2 of the second pre-injection J2 acquired in step S13. To control. Then, the control device 50 injects the fuel injection amount Q2 of the second pre-injection J2 acquired in step S13, and then ends the process.
　一方、当該クランク角度が第２プレ噴射Ｊ２の燃料噴射開始時期でないと判定した場合には（Ｓ２４：ＮＯ）、制御装置５０は、ステップＳ２５に進む。ステップＳ２５において、制御装置５０は、水噴射フラグをＲＡＭから読み出し、「ＯＮ」に設定されているか否か、つまり、今回の水噴射Ｋ１の水噴射量Ｑ５及び水噴射開始時期が設定されているか否かを判定する。そして、水噴射フラグが「ＯＦＦ」に設定されていると判定した場合には（Ｓ２５：ＮＯ）、制御装置５０は、後述のステップＳ２９に進む。 On the other hand, if it is determined that the crank angle is not the fuel injection start time of the second pre-injection J2 (S24: NO), the control device 50 proceeds to step S25. In step S25, the control device 50 reads the water injection flag from the RAM and whether or not it is set to "ON", that is, whether or not the water injection amount Q5 and the water injection start timing of the current water injection K1 are set. Judge whether or not. Then, when it is determined that the water injection flag is set to "OFF" (S25: NO), the control device 50 proceeds to step S29 described later.
　一方、水噴射フラグが「ＯＮ」に設定されていると判定した場合には（Ｓ２５：ＹＥＳ）、制御装置５０は、ステップＳ２６に進む。ステップＳ２６において、制御装置５０は、ステップＳ１１で取得したクランク角度と、ステップＳ２０で取得した水噴射Ｋ１の水噴射開始時期と、をＲＡＭから読み出し、当該クランク角度が水噴射Ｋ１の水噴射開始時期（図５の時間Ｔ２におけるクランク角度）であるか否かを判定する。 On the other hand, if it is determined that the water injection flag is set to "ON" (S25: YES), the control device 50 proceeds to step S26. In step S26, the control device 50 reads the crank angle acquired in step S11 and the water injection start timing of the water injection K1 acquired in step S20 from the RAM, and the crank angle is the water injection start timing of the water injection K1. (Crank angle at time T2 in FIG. 5) is determined.
　そして、当該クランク角度が水噴射Ｋ１の水噴射開始時期であると判定した場合には（Ｓ２６：ＹＥＳ）、制御装置５０は、ステップＳ２７に進む。ステップＳ２７において、制御装置５０は、図５に示すように、ステップＳ１９で取得した水噴射Ｋ１の水噴射量Ｑ５となるように今回の副噴射弁（例えば、副噴射弁６３Ａ）の作動を制御する。具体的には、図２の左側に示すよう、例えば、制御装置５０は、副噴射弁６３Ａから燃料噴射弁４３Ａの複数（例えば、８個）の燃料噴射口４９（図７及び図８参照）の周囲の所定領域ＦＬ（図７及び図８参照）に水噴射量Ｑ５の水６８を噴射するように制御する。 Then, when it is determined that the crank angle is the water injection start time of the water injection K1 (S26: YES), the control device 50 proceeds to step S27. In step S27, as shown in FIG. 5, the control device 50 controls the operation of the sub-injection valve (for example, the sub-injection valve 63A) this time so as to have the water injection amount Q5 of the water injection K1 acquired in step S19. To do. Specifically, as shown on the left side of FIG. 2, for example, the control device 50 has a plurality of (for example, eight) fuel injection ports 49 (see FIGS. 7 and 8) from the sub-injection valve 63A to the fuel injection valve 43A. It is controlled to inject water 68 having a water injection amount Q5 into a predetermined region FL (see FIGS. 7 and 8) around the water.
　これにより、燃料噴射弁４３Ａの複数の燃料噴射口４９（図７及び図８参照）の周囲の所定領域ＦＬ（図７及び図８参照）が、水６８の気化熱によって燃料Ｆの着火温度よりも低い温度に冷却される。そして、制御装置５０は、ステップＳ１９で取得した水噴射Ｋ１の水噴射量Ｑ５を噴射した後、ステップＳ２８に進む。ステップＳ２８において、制御装置５０は、水噴射フラグをＲＡＭから読み出し、「ＯＦＦ」に設定して、再度ＲＡＭに記憶した後、当該処理を終了する。 As a result, the predetermined region FL (see FIGS. 7 and 8) around the plurality of fuel injection ports 49 (see FIGS. 7 and 8) of the fuel injection valve 43A is set from the ignition temperature of the fuel F by the heat of vaporization of the water 68. Is also cooled to a low temperature. Then, the control device 50 injects the water injection amount Q5 of the water injection K1 acquired in step S19, and then proceeds to step S28. In step S28, the control device 50 reads the water injection flag from the RAM, sets it to “OFF”, stores it in the RAM again, and then ends the process.
　一方、当該クランク角度が水噴射Ｋ１の水噴射開始時期でないと判定した場合には（Ｓ２６：ＮＯ）、制御装置５０は、ステップＳ２９に進む。ステップＳ２９において、制御装置５０は、ステップＳ１１で取得したクランク角度と、ステップＳ１４で取得した主噴射ＪＭ１の燃料噴射開始時期と、をＲＡＭから読み出し、当該クランク角度が主噴射ＪＭ１の燃料噴射開始時期（図５の時間Ｔ４におけるクランク角度）であるか否かを判定する。そして、当該クランク角度が主噴射ＪＭ１の燃料噴射開始時期でないと判定した場合には（Ｓ２９：ＮＯ）、制御装置５０は、当該処理を終了する。 On the other hand, if it is determined that the crank angle is not the water injection start time of the water injection K1 (S26: NO), the control device 50 proceeds to step S29. In step S29, the control device 50 reads the crank angle acquired in step S11 and the fuel injection start timing of the main injection JM1 acquired in step S14 from the RAM, and the crank angle is the fuel injection start timing of the main injection JM1. (Crank angle at time T4 in FIG. 5) is determined. Then, when it is determined that the crank angle is not the fuel injection start time of the main injection JM1 (S29: NO), the control device 50 ends the process.
　一方、当該クランク角度が主噴射ＪＭ１の燃料噴射開始時期であると判定した場合には（Ｓ２９：ＹＥＳ）、制御装置５０は、ステップＳ３０に進む。ステップＳ３０において、制御装置５０は、図５に示すように、ステップＳ１３で取得した主噴射ＪＭ１の燃料噴射量Ｑ３となるように今回の燃料噴射弁（例えば、燃料噴射弁４３Ａ）の作動を制御する。具体的には、図２の右側に示すように、例えば、制御装置５０は、燃料噴射弁４３Ａの複数（例えば、８個）の燃料噴射口４９（図７及び図８参照）からピストン７３に形成されたキャビティ７６内の周辺部に向けて燃料噴射量Ｑ３の燃料Ｆを噴射するように制御する。 On the other hand, when it is determined that the crank angle is the fuel injection start time of the main injection JM1 (S29: YES), the control device 50 proceeds to step S30. In step S30, as shown in FIG. 5, the control device 50 controls the operation of the fuel injection valve (for example, the fuel injection valve 43A) this time so as to be the fuel injection amount Q3 of the main injection JM1 acquired in step S13. To do. Specifically, as shown on the right side of FIG. 2, for example, the control device 50 is connected to the piston 73 from a plurality of (for example, eight) fuel injection ports 49 (see FIGS. 7 and 8) of the fuel injection valve 43A. The fuel F of the fuel injection amount Q3 is controlled to be injected toward the peripheral portion in the formed cavity 76.
　これにより、図７及び図８に示すように、燃料噴射弁４３Ａの各燃料噴射口４９から噴射された燃料Ｆは、副噴射弁６３Ａから噴射された水６８の気化熱によって燃料Ｆの着火温度よりも低い温度に冷却された所定領域ＦＬを通過するまで着火が遅れ、燃料Ｆと空気との混合が促進される。つまり、図５に示すように、主噴射ＪＭ１は、従来の主噴射ＪＭ２に対して時間Ｔ１だけ早く噴射されて、所定領域ＦＬ内を着火せずに通過する。これにより、噴射された燃料Ｆと空気との混合が従来よりも促進され、スモークの低減化を図ることができる。 As a result, as shown in FIGS. 7 and 8, the fuel F injected from each fuel injection port 49 of the fuel injection valve 43A has the ignition temperature of the fuel F due to the heat of vaporization of the water 68 injected from the sub-injection valve 63A. Ignition is delayed until it passes through a predetermined region FL cooled to a lower temperature, and mixing of fuel F and air is promoted. That is, as shown in FIG. 5, the main injection JM1 is injected earlier than the conventional main injection JM2 by the time T1 and passes through the predetermined region FL without ignition. As a result, mixing of the injected fuel F and air is promoted as compared with the conventional case, and smoke can be reduced.
　一方、所定領域ＦＬの外側に進んだ燃料Ｆは、着火領域ＦＡにおいて着火される。即ち、所定領域ＦＬは、燃料噴射弁４３Ａから噴射された主噴射ＪＭ１の燃料Ｆが着火する着火領域ＦＡよりも燃料噴射口４９側の領域である。また、図５に示すように、副噴射弁６３Ａから噴射された水６８は、燃焼火炎から直接受熱（熱回収）して気化膨張を増大するため、圧縮上死点ＴＤＣ以降において、筒内圧が従来よりも所定圧力ΔＰだけ上昇し、出力トルクを増大させることが可能となり、引いては燃費の向上を図ることができる。 On the other hand, the fuel F that has advanced to the outside of the predetermined region FL is ignited in the ignition region FA. That is, the predetermined region FL is a region on the fuel injection port 49 side of the ignition region FA where the fuel F of the main injection JM1 injected from the fuel injection valve 43A ignites. Further, as shown in FIG. 5, the water 68 injected from the sub-injection valve 63A directly receives heat (heat recovery) from the combustion flame to increase vaporization and expansion, so that the in-cylinder pressure increases after the compression top dead center TDC. It is possible to increase the output torque by increasing the predetermined pressure ΔP as compared with the conventional case, and it is possible to improve the fuel efficiency.
　他方、燃焼室７５（図２参照）の壁面付近には高温（例えば、約６００℃以上）の空気が存在するため、仮に複数（例えば、８個）の燃料噴射口４９の周囲の所定領域ＦＬの温度が過度に冷却されても、燃焼室７５の壁面付近において、確実に着火されて、失火するおそれがない。従って、燃焼室７５内全体を冷却するよりも燃焼ロバスト性を高くすることができる。また、副噴射弁６３Ａ～６３Ｄを介して、複数の燃料噴射口４９の周囲の所定領域ＦＬのみに水６８を噴射するため、水６８の消費量を抑えることができる。 On the other hand, since high temperature (for example, about 600 ° C. or higher) air exists near the wall surface of the combustion chamber 75 (see FIG. 2), a predetermined region FL around a plurality of (for example, eight) fuel injection ports 49 is assumed. Even if the temperature of the combustion chamber is excessively cooled, it is surely ignited in the vicinity of the wall surface of the combustion chamber 75, and there is no risk of misfire. Therefore, the combustion robustness can be improved as compared with cooling the entire inside of the combustion chamber 75. Further, since the water 68 is injected only into the predetermined region FL around the plurality of fuel injection ports 49 via the sub-injection valves 63A to 63D, the consumption of the water 68 can be suppressed.
　続いて、図４に示すように、ステップＳ３０で、ステップＳ１３で取得した主噴射ＪＭ１の燃料噴射量Ｑ３を噴射した後、制御装置５０は、ステップＳ３１に進む。ステップＳ３１において、制御装置５０は、燃料噴射フラグをＲＡＭから読み出し、「ＯＦＦ」に設定して、再度ＲＡＭに記憶した後、当該処理を終了する。 Subsequently, as shown in FIG. 4, in step S30, after injecting the fuel injection amount Q3 of the main injection JM1 acquired in step S13, the control device 50 proceeds to step S31. In step S31, the control device 50 reads the fuel injection flag from the RAM, sets it to “OFF”, stores it in the RAM again, and then ends the process.
　また、水６８は、内燃機関１０の外側に配置された水タンク６７（液体タンク）に貯留され、水ポンプ６６によって水タンク６７から各副噴射弁６３Ａ～６３Ｄに供給される。これにより、内燃機関１０の温度上昇による水６８の温度上昇を抑制することができ、各燃料噴射弁４３Ａ～４３Ｄの複数の燃料噴射口４９の周囲の所定領域ＦＬの水６８の気化による冷却効果を高めることができる。 Further, the water 68 is stored in a water tank 67 (liquid tank) arranged outside the internal combustion engine 10, and is supplied from the water tank 67 to each of the sub-injection valves 63A to 63D by the water pump 66. As a result, it is possible to suppress the temperature rise of the water 68 due to the temperature rise of the internal combustion engine 10, and the cooling effect due to the vaporization of the water 68 in the predetermined region FL around the plurality of fuel injection ports 49 of the fuel injection valves 43A to 43D. Can be enhanced.
　尚、本発明は前記実施形態に限定されることはなく、本発明の要旨を逸脱しない範囲内で種々の改良、変形、追加、削除が可能であることは勿論である。例えば、以下のようにしてもよい。尚、以下の説明において上記図１～図８の前記実施形態に係る内燃機関１０等と同一符号は、前記実施形態に係る内燃機関１０等と同一あるいは相当部分を示すものである。 It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that various improvements, modifications, additions, and deletions can be made without departing from the gist of the present invention. For example, it may be as follows. In the following description, the same reference numerals as the internal combustion engine 10 and the like according to the embodiment of FIGS. 1 to 8 indicate the same or equivalent parts as the internal combustion engine 10 and the like according to the embodiment.
他の第１実施形態Another First Embodiment
　（Ａ）例えば、図９に示すように、各副噴射弁６３Ａ～６３Ｄに替えて、素焼きのセラミックスを含む多孔質材で略円筒状に形成されて、各燃料噴射弁４３Ａ～４３Ｄが上方から嵌入される筒状部材８２を設け、各燃焼室７５の上壁面の中央に形成された貫通孔７２Ａに、筒状部材８２の下端部が燃焼室７５に対向するように嵌入してもよい。つまり、シリンダヘッド７２に、燃焼室７５に対向して燃料噴射弁４３Ａ～４３Ｄが配置される貫通孔７２Ａが形成されていてもよい。また、筒状部材８２の長さは、シリンダヘッド７２の厚さとほぼ同じ長さに形成され、筒状部材８２の下端面は、燃焼室７５の上壁面と面一になるように設けられている。尚、図９には、燃料噴射弁４３Ａが上方から嵌入される筒状部材８２を例示している。 (A) For example, as shown in FIG. 9, instead of the sub-injection valves 63A to 63D, the fuel injection valves 43A to 43D are formed in a substantially cylindrical shape with a porous material containing unglazed ceramics, and the fuel injection valves 43A to 43D are from above. The tubular member 82 to be fitted may be provided and fitted into the through hole 72A formed in the center of the upper wall surface of each combustion chamber 75 so that the lower end portion of the tubular member 82 faces the combustion chamber 75. That is, the cylinder head 72 may be formed with a through hole 72A in which the fuel injection valves 43A to 43D are arranged so as to face the combustion chamber 75. Further, the length of the tubular member 82 is formed to be substantially the same as the thickness of the cylinder head 72, and the lower end surface of the tubular member 82 is provided so as to be flush with the upper wall surface of the combustion chamber 75. There is. Note that FIG. 9 illustrates a tubular member 82 into which the fuel injection valve 43A is fitted from above.
　また、下方に開放された断面円形の略箱体状に形成された４つの供給部材８１が、各筒状部材８２のそれぞれの上端面を全面に渡って覆うように同軸に、シリンダヘッド７２に設けられている。各供給部材８１の天井部の中心には、各燃料噴射弁４３Ａ～４３Ｄが上方から嵌入される貫通孔８１Ａが形成されている。各供給部材８１のそれぞれには、各水配管６２Ａ～６２Ｄが接続されている。そして、各燃料噴射弁４３Ａ～４３Ｄが、各供給部材８１の貫通孔８１Ａ、及び、各筒状部材８２に上方から嵌入されて固定されている。尚、図９には、水配管６２Ａを例示している。 Further, four supply members 81 formed in a substantially box shape having a circular cross section open downward are coaxially attached to the cylinder head 72 so as to cover the upper end surface of each of the tubular members 82 over the entire surface. It is provided. A through hole 81A into which the fuel injection valves 43A to 43D are fitted from above is formed in the center of the ceiling portion of each supply member 81. Water pipes 62A to 62D are connected to each of the supply members 81. Then, the fuel injection valves 43A to 43D are fitted and fixed to the through holes 81A of the supply members 81 and the tubular members 82 from above. Note that FIG. 9 illustrates the water pipe 62A.
　そして、各水配管６２Ａ～６２Ｄ及び各供給部材８１を介して、各筒状部材８２の上端面に水６８が供給されて、筒状部材８２の下端面から水６８が染み出る。これにより、図９の左側に示すように、水６８が、各燃料噴射弁４３Ａ～４３Ｄの複数の燃料噴射口４９（図７参照）の周囲の所定領域ＦＬに供給され、水６８の気化熱によって当該所定領域ＦＬが燃料Ｆの着火温度よりも低い温度に冷却される。 Then, water 68 is supplied to the upper end surface of each tubular member 82 via the water pipes 62A to 62D and each supply member 81, and the water 68 seeps out from the lower end surface of the tubular member 82. As a result, as shown on the left side of FIG. 9, the water 68 is supplied to the predetermined region FL around the plurality of fuel injection ports 49 (see FIG. 7) of the fuel injection valves 43A to 43D, and the heat of vaporization of the water 68. The predetermined region FL is cooled to a temperature lower than the ignition temperature of the fuel F.
　そして、図９の右側に示すように、燃料噴射弁４３Ａの各燃料噴射口４９から噴射された主噴射ＪＭ１の燃料Ｆは、水６８の気化熱によって燃料Ｆの着火温度よりも低い温度に冷却された所定領域ＦＬを通過するまで着火が遅れ、燃料Ｆと空気との混合が促進される。つまり、主噴射ＪＭ１の燃料Ｆは、所定領域ＦＬ内を着火せずに通過する。これにより、噴射された燃料Ｆと空気との混合が従来よりも促進され、スモークの低減化を図ることができる。 Then, as shown on the right side of FIG. 9, the fuel F of the main injection JM1 injected from each fuel injection port 49 of the fuel injection valve 43A is cooled to a temperature lower than the ignition temperature of the fuel F by the heat of vaporization of water 68. Ignition is delayed until the fuel F passes through the predetermined region FL, and the mixing of the fuel F and the air is promoted. That is, the fuel F of the main injection JM1 passes through the predetermined region FL without ignition. As a result, mixing of the injected fuel F and air is promoted as compared with the conventional case, and smoke can be reduced.
　一方、所定領域ＦＬの外側に進んだ燃料Ｆは、着火領域ＦＡ（図７及び図８参照）において着火される。即ち、所定領域ＦＬは、燃料噴射弁４３Ａから噴射された主噴射ＪＭ１の燃料Ｆが着火する着火領域ＦＡよりも燃料噴射口４９側の領域である。また、筒状部材８２の下端面から染み出た水６８は、燃焼火炎から直接受熱（熱回収）して気化膨張を増大するため、圧縮上死点ＴＤＣ以降において、筒内圧が従来よりも所定圧力ΔＰ（図５参照）だけ上昇し、出力トルクを増大させることが可能となり、引いては燃費の向上を図ることができる。 On the other hand, the fuel F that has advanced to the outside of the predetermined region FL is ignited in the ignition region FA (see FIGS. 7 and 8). That is, the predetermined region FL is a region on the fuel injection port 49 side of the ignition region FA where the fuel F of the main injection JM1 injected from the fuel injection valve 43A ignites. Further, the water 68 exuding from the lower end surface of the tubular member 82 directly receives heat (heat recovery) from the combustion flame to increase vaporization and expansion, so that the in-cylinder pressure is set higher than before after the compression top dead center TDC. The pressure ΔP (see FIG. 5) can be increased to increase the output torque, which in turn can improve fuel efficiency.
　他方、燃焼室７５（図２参照）の壁面付近には高温（例えば、約６００℃以上）の空気が存在するため、仮に複数（例えば、８個）の燃料噴射口４９の周囲の所定領域ＦＬの温度が過度に冷却されても、燃焼室７５の壁面付近において、確実に着火されて、失火するおそれがない。従って、燃焼室７５内全体を冷却するよりも燃焼ロバスト性を高くすることができる。 On the other hand, since high temperature (for example, about 600 ° C. or higher) air exists near the wall surface of the combustion chamber 75 (see FIG. 2), a predetermined region FL around a plurality of (for example, eight) fuel injection ports 49 is assumed. Even if the temperature of the combustion chamber is excessively cooled, it is surely ignited in the vicinity of the wall surface of the combustion chamber 75, and there is no risk of misfire. Therefore, the combustion robustness can be improved as compared with cooling the entire inside of the combustion chamber 75.
他の第２実施形態Another second embodiment
　（Ｂ）また、例えば、各副噴射弁６３Ａ～６３Ｄを介して、水６８を複数（例えば、８個）の燃料噴射口４９の周囲の所定領域ＦＬに噴射したが、水６８に限らず、軽油等の燃料Ｆよりも着火性が劣るメタノール等の液体を所定領域ＦＬに噴射してもよい。これにより、メタノール等の液体の気化熱によって所定領域ＦＬ内を冷却して、燃料Ｆと空気との混合を促進し、スモークの低減化を図ることができる。 (B) Further, for example, water 68 is injected into a predetermined region FL around a plurality of (for example, eight) fuel injection ports 49 via the sub-injection valves 63A to 63D, but the water 68 is not limited to the water 68. A liquid such as methanol, which is inferior in ignitability to fuel F such as light oil, may be injected into the predetermined region FL. As a result, the inside of the predetermined region FL can be cooled by the heat of vaporization of a liquid such as methanol to promote mixing of the fuel F and air, and smoke can be reduced.
他の第３実施形態Another third embodiment
　（Ｃ）また、例えば、内燃機関１０の不図示のウォータポンプで、冷却用クーラントの一部を各副噴射弁６３Ａ～６３Ｄに供給するようにしてもよい。これにより、内燃機関１０の駆動時だけ冷却用クーラントの一部を各副噴射弁６３Ａ～６３Ｄに供給して所定領域ＦＬ内に噴射することが可能となる。 (C) Further, for example, a water pump (not shown) of the internal combustion engine 10 may supply a part of the cooling coolant to the sub-injection valves 63A to 63D. As a result, a part of the cooling coolant can be supplied to the sub-injection valves 63A to 63D and injected into the predetermined region FL only when the internal combustion engine 10 is driven.
　１０　　内燃機関
　４３Ａ～４３Ｄ　　燃料噴射弁
　４９　　燃料噴射口
　５０　　制御装置
　６３Ａ～６３Ｄ　　副噴射弁
　６６　　水ポンプ
　６７　　水タンク
　６８　　水
　７２　　シリンダヘッド
　７２Ａ　　貫通孔
　７５　　燃焼室
　８１　　供給部材
　８２　　筒状部材
　Ｊ１　　第１プレ噴射
　Ｊ２　　第２プレ噴射
　ＪＭ１　　主噴射
　Ｆ　　燃料
　ＦＡ　　着火領域
　ＦＬ　　所定領域 10 Internal combustion engine 43A-43D Fuel injection valve 49 Fuel injection port 50 Control device 63A-63D Sub-injection valve 66 Water pump 67 Water tank 68 Water 72 Cylinder head 72A Through hole 75 Combustion chamber 81 Supply member 82 Cylindrical member J1 1st pre Injection J2 2nd pre-injection JM1 Main injection F Fuel FA Ignition area FL Predetermined area

Claims (6)

  1. 　内燃機関の燃焼室で燃料を噴射する燃料噴射弁と、
    　前記燃焼室内に前記燃料よりも着火性が劣る液体を供給する冷却媒体供給装置と、
    　を備え、
    　前記燃料噴射弁が燃料の主噴射を行う前に、前記冷却媒体供給装置によって前記燃料噴射弁の複数の燃料噴射口の周囲の所定領域に前記液体を供給して、前記所定領域の温度を下げる、
    　内燃機関。     A fuel injection valve that injects fuel in the combustion chamber of an internal combustion engine,
    A cooling medium supply device that supplies a liquid that is inferior in ignitability to the fuel into the combustion chamber,
    With
    Before the fuel injection valve performs main injection of fuel, the cooling medium supply device supplies the liquid to predetermined regions around a plurality of fuel injection ports of the fuel injection valve to lower the temperature of the predetermined region. ,
    Internal combustion engine.
  2. 　請求項１に記載の内燃機関において、
    　前記所定領域は、前記燃料噴射弁から噴射された主噴射の燃料が着火する着火領域よりも前記燃料噴射口側の領域である、
    　内燃機関。     In the internal combustion engine according to claim 1,
    The predetermined region is a region on the fuel injection port side of the ignition region where the fuel of the main injection injected from the fuel injection valve ignites.
    Internal combustion engine.
  3. 　請求項１又は請求項２に記載の内燃機関において、
    　前記冷却媒体供給装置は、前記燃焼室で前記液体を前記所定領域に噴射する副噴射弁を有し、
    　前記内燃機関は、前記燃料噴射弁による燃料噴射を制御すると共に、前記副噴射弁による前記液体の噴射を制御する噴射制御装置を備え、
    　前記噴射制御装置は、
    　前記燃料噴射弁が複数回のプレ噴射を行った後に、前記主噴射を行うように制御する燃料噴射制御部と、
    　複数回の前記プレ噴射が行われた後に、前記副噴射弁が前記主噴射が行われる前に前記液体を前記所定領域に噴射するように制御する冷却媒体噴射制御部と、
    　を有する、
    　内燃機関。     In the internal combustion engine according to claim 1 or 2.
    The cooling medium supply device has an auxiliary injection valve that injects the liquid into the predetermined region in the combustion chamber.
    The internal combustion engine includes an injection control device that controls fuel injection by the fuel injection valve and controls injection of the liquid by the sub-injection valve.
    The injection control device is
    A fuel injection control unit that controls the main injection after the fuel injection valve has performed a plurality of pre-injections.
    A cooling medium injection control unit that controls the sub-injection valve to inject the liquid into the predetermined region after the pre-injection is performed a plurality of times and before the main injection is performed.
    Have,
    Internal combustion engine.
  4. 　請求項１又は請求項２に記載の内燃機関において、
    　前記燃焼室に対向して前記燃料噴射弁が配置される貫通孔が形成されたシリンダヘッドを備え、
    　前記冷却媒体供給装置は、
    　素焼きのセラミックスを含む多孔質材で筒状に形成されて、下端部が前記燃焼室に対向するように前記貫通孔に嵌め込まれると共に、前記燃料噴射弁が上方から挿通される筒状部材と、
    　前記シリンダヘッドに設けられて前記筒状部材の上端部に前記液体を供給する供給部材と、
    　を有し、
    　前記筒状部材の下端部から前記液体が染み出て、複数の前記燃料噴射口の周囲の所定領域に前記液体を供給して、前記所定領域の温度を下げる、
    　内燃機関。     In the internal combustion engine according to claim 1 or 2.
    A cylinder head having a through hole for arranging the fuel injection valve facing the combustion chamber is provided.
    The cooling medium supply device is
    A tubular member formed of a porous material containing unglazed ceramics into a tubular shape, the lower end of which is fitted into the through hole so as to face the combustion chamber, and a tubular member through which the fuel injection valve is inserted from above.
    A supply member provided on the cylinder head and supplying the liquid to the upper end of the tubular member,
    Have,
    The liquid exudes from the lower end of the tubular member, supplies the liquid to a predetermined region around the plurality of fuel injection ports, and lowers the temperature of the predetermined region.
    Internal combustion engine.
  5. 　請求項１乃至請求項４のいずれか１項に記載の内燃機関において、
    　前記内燃機関の外側に配置されて前記液体を貯留する液体タンクと、
    　前記液体タンクから前記冷却媒体供給装置へ前記液体を供給する液体供給装置と、
    　を備えた、
    　内燃機関。     In the internal combustion engine according to any one of claims 1 to 4.
    A liquid tank arranged outside the internal combustion engine to store the liquid,
    A liquid supply device that supplies the liquid from the liquid tank to the cooling medium supply device,
    With,
    Internal combustion engine.
  6. 　請求項１乃至請求項５のいずれか１項に記載の内燃機関において、
    　前記液体は、水を含む非燃焼液体である、
    　内燃機関。     In the internal combustion engine according to any one of claims 1 to 5.
    The liquid is a non-combustible liquid containing water.
    Internal combustion engine.
PCT/JP2020/034540 2019-10-04 2020-09-11 Internal combustion engine WO2021065426A1 (en)

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