WO2015125208A1 - Fuel supplying system - Google Patents

Fuel supplying system Download PDF

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Publication number
WO2015125208A1
WO2015125208A1 PCT/JP2014/053756 JP2014053756W WO2015125208A1 WO 2015125208 A1 WO2015125208 A1 WO 2015125208A1 JP 2014053756 W JP2014053756 W JP 2014053756W WO 2015125208 A1 WO2015125208 A1 WO 2015125208A1
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WO
WIPO (PCT)
Prior art keywords
fuel
pressure
supply
controller
engine
Prior art date
Application number
PCT/JP2014/053756
Other languages
French (fr)
Japanese (ja)
Inventor
南　亘
荒井　康
律文 小出
健太郎 糸賀
祥司 山口
拓志 中本
Original Assignee
日立建機株式会社
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Application filed by 日立建機株式会社 filed Critical 日立建機株式会社
Priority to PCT/JP2014/053756 priority Critical patent/WO2015125208A1/en
Publication of WO2015125208A1 publication Critical patent/WO2015125208A1/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/30—Controlling fuel injection
    • F02D41/38—Controlling fuel injection of the high pressure type
    • F02D41/3809—Common rail control systems
    • F02D41/3836—Controlling the fuel pressure
    • F02D41/3845—Controlling the fuel pressure by controlling the flow into the common rail, e.g. the amount of fuel pumped
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/04—Introducing corrections for particular operating conditions
    • F02D41/06—Introducing corrections for particular operating conditions for engine starting or warming up
    • F02D41/062—Introducing corrections for particular operating conditions for engine starting or warming up for starting
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/22—Safety or indicating devices for abnormal conditions
    • F02D41/221—Safety or indicating devices for abnormal conditions relating to the failure of actuators or electrically driven elements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/22—Safety or indicating devices for abnormal conditions
    • F02D2041/224—Diagnosis of the fuel system
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/02—Input parameters for engine control the parameters being related to the engine
    • F02D2200/10—Parameters related to the engine output, e.g. engine torque or engine speed
    • F02D2200/101—Engine speed
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/50—Input parameters for engine control said parameters being related to the vehicle or its components
    • F02D2200/503—Battery correction, i.e. corrections as a function of the state of the battery, its output or its type

Definitions

  • the present invention relates to a fuel supply system used for an engine of a work vehicle such as a hydraulic excavator.
  • a fuel injection device used for an engine of a work vehicle such as a hydraulic excavator generally includes a nozzle for injecting fuel and an injection valve for opening and closing the nozzle. Further, a system (fuel supply system) that supplies fuel to a combustion chamber of an engine using this fuel injection device is known (see, for example, Patent Document 1).
  • a high-pressure pump sucks up fuel from a fuel tank and pressurizes it into high-pressure fuel.
  • the high pressure pump supplies high pressure fuel to the fuel pressure accumulator.
  • the fuel pressure accumulator stores the high-pressure fuel supplied from the high-pressure pump in a high-pressure state, and supplies a part of the high-pressure fuel to the fuel injection device.
  • the high pressure fuel is injected into the combustion chamber of the engine by opening the injection valve and opening the injection hole.
  • the conventional fuel supply system as disclosed in Patent Document 1, it is determined whether or not the operation of the fuel injection device is defective when the engine is started.
  • the conventional fuel supply system determines that the operation of the fuel injection device is defective, it determines that the injection amount is insufficient and increases the supply time of the high-pressure fuel supplied to the fuel injection device to increase the high pressure. Increase fuel supply.
  • the conventional fuel supply system solves the shortage of the injection amount.
  • the injection amount is insufficient when the load on the engine becomes high, or when the components of the fuel injection device wear out and the leakage amount of high-pressure fuel increases. It is possible to cope with this case.
  • the cause of the malfunction of the fuel injection device may be due to impurities in the fuel. This case will be specifically described.
  • the nozzle hole of the fuel injection device is clogged with impurities in the fuel, the impurities adhere to the injection valve. As a result, the injection valve does not operate smoothly, and the operation of the fuel injection device becomes defective.
  • the conventional fuel supply system only increases the supply time of the high-pressure fuel supplied to the fuel injection device. Therefore, the fuel injection device does not recover the lubrication operation of the injection valve, so that the shortage of the injection amount is not solved and sufficient fuel cannot be supplied to the combustion chamber of the engine.
  • the present invention has been made in view of the above problems, and an object of the present invention is to provide a fuel supply system capable of increasing the supply capacity of fuel supplied to a combustion chamber of an engine when the engine is started.
  • the fuel supply system of the present invention comprises: A high-pressure pump connected to the fuel tank by a first supply pipe, and sucking up the fuel in the fuel tank from the fuel tank via the first supply pipe and pressurizing the fuel tank into a high-pressure fuel; A fuel pressure accumulator connected to the high pressure pump by a second supply pipe and storing the high pressure fuel supplied from the high pressure pump in a high pressure state; An injection valve that is connected to the fuel pressure storage device by a third supply pipe and is supplied with the high-pressure fuel from the fuel pressure storage device, and is opened by opening the injection valve to inject the high-pressure fuel into the combustion chamber of the engine.
  • a fuel injection device having an injection hole;
  • a fuel supply valve connected to the first supply pipe and controlling the supply pressure of the high-pressure fuel supplied to the fuel injection device by controlling the supply pressure of the fuel supplied to the high-pressure pump;
  • a detection device for detecting an operating state of the fuel injection device;
  • a controller for controlling the operation of the injection valve and the operation of the fuel supply valve according to the detection result of the detection device;
  • a key switch input detection device that is connected to the controller and detects the presence or absence of an input of the key switch of the engine; When the controller determines that there is an input from the key switch by the key switch input detection device, the controller determines whether the operation of the fuel injection device is defective by the detection device, and the fuel injection device When it is determined that the operation of the high pressure fuel is poor, the operation of the fuel supply valve is controlled to increase the supply pressure of the high pressure fuel by increasing the supply pressure of the fuel supplied to the high pressure pump.
  • the fuel supply system of the present invention increases the supply pressure of the high-pressure fuel supplied to the fuel injection device when it is determined that the operation of the fuel injection device is defective.
  • the fuel supply system of the present invention removes impurities from the injection valve using the supply pressure of the high-pressure fuel even if the fuel injection device becomes defective due to adhesion of impurities in the fuel to the injection valve. It becomes possible to do.
  • the impurities removed from the injection valve are melted by the temperature of the high-pressure fuel and injected together with the high-pressure fuel from the injection hole, so that the lubricating operation of the injection valve is restored. Therefore, the fuel supply system of the present invention can solve the shortage of the injection amount even when the cause of the malfunction of the fuel injection device is due to impurities in the fuel.
  • the supply pressure of the high-pressure fuel supplied to the fuel injection device is increased by increasing the supply pressure of the high-pressure fuel even if the injection time is the same as the conventional fuel supply system. Therefore, the fuel supply system of the present invention has a shortage of injection amount due to a shortage of injection amount due to a high load on the engine or due to wear of components of the fuel injection device and an increase in the amount of high-pressure fuel leakage. Even in this case, the shortage of the injection amount can be resolved as in the conventional fuel supply system. Therefore, the fuel supply system of the present invention can increase the fuel supply capacity to the combustion chamber of the engine when the engine is started.
  • FIG. 1 is a block diagram of a fuel supply system showing an embodiment of the present invention. It is a flowchart which shows the fuel supply control process at the time of engine starting by the controller of the fuel supply system of the embodiment. It is a figure which shows the relationship between the actual rotation speed of the engine at the time of engine starting in this Embodiment, and the supply pressure of a high pressure fuel. It is a figure which shows the relationship between the actual rotation speed of the engine at the time of engine starting in this Embodiment, and the supply pressure of a high pressure fuel.
  • FIG. 1 is a block diagram of a fuel supply system 1 showing an embodiment of the present invention.
  • the fuel supply system 1 is used for an engine of a work vehicle such as a hydraulic excavator.
  • a solid line flow indicates a fuel flow
  • a dotted line flow indicates a control signal flow.
  • the fuel supply system 1 includes a fuel tank 2, a high-pressure pump 3, a fuel pressure accumulation device 4, and a fuel injection device 5.
  • the fuel tank 2 stores the engine fuel.
  • the high-pressure pump 3 is connected to the fuel tank 2 by a first supply pipe 21.
  • the high-pressure pump 3 sucks up and pressurizes the fuel in the fuel tank 2 from the fuel tank 2 through the first supply pipe 21 to form high-pressure fuel, and supplies the high-pressure fuel to the fuel pressure accumulator 4. is there.
  • the fuel pressure accumulator 4 is connected to the high-pressure pump 3 through a second supply pipe 22.
  • the fuel accumulator 4 stores the high-pressure fuel supplied from the high-pressure pump 3 via the second supply pipe 22 in a high-pressure state and supplies a part of the high-pressure fuel to the fuel injection device.
  • the fuel injection device 5 injects high-pressure fuel supplied from the fuel accumulator 4 into the combustion chamber 102 of the engine 101.
  • This fuel injection device 5 is connected to the fuel pressure accumulator 4 by a third supply pipe 23.
  • the third supply pipe 23 is connected to the main body 51.
  • a nozzle hole 52 is provided at the tip of the main body 51.
  • An injection valve 53 is provided inside the main body 51. This injection valve 53 opens and closes the injection hole 52.
  • the fuel injection device 5 injects high-pressure fuel into the combustion chamber 102 of the engine 101 by opening the injection valve 53 and opening the injection hole 52.
  • a fuel return pipe (not shown) is connected to the main body 51. This return pipe is connected to the fuel tank 2. The fuel leaking from the fuel injection device 5 is returned to the fuel tank 2 through this return pipe.
  • the fuel supply valve 6 is connected to the first supply pipe 21.
  • the fuel supply valve 6 controls the supply pressure of the high-pressure fuel supplied to the fuel injection device 5 by controlling the supply pressure of the fuel supplied to the high-pressure pump 3.
  • a fuel pressure gauge 7 and a fuel thermometer 8 are connected to the fuel pressure accumulator 4.
  • the fuel pressure gauge 7 measures the pressure of the high pressure fuel stored in the fuel pressure accumulator 4 (supply pressure of the high pressure fuel).
  • the fuel thermometer 8 measures the temperature of the high-pressure fuel stored in the fuel pressure accumulator 4.
  • a safety valve 9 is connected to the fuel pressure accumulator 4.
  • the safety valve 9 prevents the fuel pressure accumulating device 4 from being damaged due to an excessive increase in the supply pressure of the high-pressure fuel. This content will be specifically described.
  • the safety valve 9 discharges the high-pressure fuel and lowers the supply pressure of the high-pressure fuel when the supply pressure of the high-pressure fuel exceeds the operating pressure of the safety valve 9.
  • the operating pressure of the safety valve 9 is an abnormal pressure that may cause a failure in the fuel accumulator due to the supply pressure of the high-pressure fuel.
  • the fuel supply system 1 includes a controller 10.
  • This controller 10 controls the drive of the high-pressure pump 3, controls the operation of the injection valve 53 of the fuel injection device 5, and controls the operation of the fuel supply valve 6.
  • the controller 10 is connected to an engine speed detector 11 that detects the actual engine speed.
  • the controller 10 is connected to a key switch input detection device 12 that detects the presence or absence of an input of an engine key switch.
  • the high-pressure pump 3 is driven by the controller 10, and the high-pressure pump 3 sucks up the fuel in the fuel tank 2 and pressurizes it to make high-pressure fuel.
  • the high pressure pump 3 supplies the high pressure fuel to the fuel pressure accumulator 4.
  • the fuel accumulator 4 stores the high-pressure fuel supplied from the high-pressure pump 3 in a high-pressure state and supplies a part of the high-pressure fuel to the injection valve 53 of the fuel injector 5.
  • the controller 10 opens the injection hole 52 by opening the injection valve 53. As a result, high-pressure fuel is injected from the injection hole 52 into the combustion chamber 102 of the engine 101.
  • controller 10 controls the injection and the injection amount by controlling the operation of the injection valve 53 and the operation of the fuel supply valve 6 according to the actual engine speed detected from the engine speed detection device 11. Yes.
  • Step S1 The controller 10 uses the key switch input detection device 12 to determine whether or not the key switch is input.
  • Step S2 If the controller 10 determines in step S1 that the key switch is input (the determination result in step S1 is YES), the fuel pressure gauge 7 causes the high-pressure fuel supply pressure to be equal to or higher than the operating pressure of the high-pressure pump 3. Determine whether or not.
  • the operating pressure of the high pressure pump 3 is the minimum pressure necessary for the operation of the high pressure pump 3.
  • a specific value of the operating pressure of the high-pressure pump 3 is, for example, 20 MPa.
  • step S2 When the supply pressure of the high-pressure fuel is lower than the operating pressure of the high-pressure pump 3 in step S2 (the determination result in step S2 is NO), the controller 10 determines that the high-pressure pump 3 is not operating and reports an abnormality. (Step S10), the control process is terminated.
  • Step S3 When the high-pressure fuel supply pressure is equal to or higher than the operating pressure of the high-pressure pump 3 (YES in step S2), the controller 10 determines whether the high-pressure fuel supply pressure is equal to or higher than the operating pressure of the safety valve 9 by the fuel pressure gauge 7. Determine whether.
  • step S3 When the controller 10 determines in step S3 that the supply pressure of the high-pressure fuel is equal to or higher than the operating pressure of the safety valve 9 (the determination result in step S3 is YES), the controller 10 determines that there is an abnormality in the fuel pressure accumulator 4 and abnormal. (Step S10), and the control process is terminated. In this case, the safety valve 9 operates to discharge high-pressure fuel. As a result, the supply pressure of the high-pressure fuel becomes less than the operating pressure of the safety valve 9.
  • Step S4 If the controller 10 determines in step S3 that the supply pressure of the high-pressure fuel is lower than the operating pressure of the safety valve 9 (the determination result in step S3 is NO), the controller 10 changes the operating state of the fuel supply valve 6 for a predetermined time (X seconds). ) To maintain the supply pressure of the high-pressure fuel for a predetermined time (X seconds).
  • Step S5 the controller 10 uses the engine speed detection device 11 to determine whether or not the actual engine speed is equal to or higher than the target speed.
  • the engine target speed is the minimum engine speed required for starting the engine.
  • This target rotational speed is a standard for determining whether or not the operation of the fuel injection device 5 is defective.
  • a specific value of the target rotational speed is, for example, 500 rpm.
  • step S5 determines in step S5 that the actual engine speed is greater than or equal to the target engine speed (the determination result in step S5 is YES), the controller 10 determines that the engine has started and ends the control process.
  • Step S6 When the controller 10 determines in step S5 that the actual engine speed is less than the target engine speed (NO in step S5), the controller 10 controls the operation of the fuel supply valve 6 to supply the high-pressure fuel supply pressure. Raise.
  • Step S7 Subsequently, the controller 10 maintains the operating state of the fuel supply valve 6 for a predetermined time (X seconds), thereby maintaining the supply pressure of the high-pressure fuel for a predetermined time (X seconds).
  • Step S8 the controller 10 uses the engine speed detection device 11 to determine whether or not the actual engine speed is equal to or higher than the target speed.
  • This target rotational speed is the same as the target rotational speed set in step S5.
  • step S8 determines in step S8 that the actual engine speed is equal to or higher than the target engine speed (YES in step S8), the controller 10 determines that the engine has started and ends the control process.
  • Step S9 When the controller 10 determines in step S8 that the actual engine speed is less than the target engine speed (the determination result in step S8 is NO), the fuel pressure gauge 7 causes the supply pressure of the high-pressure fuel to operate the safety valve 9. Judge whether pressure is over or not.
  • Step S10 If the controller 10 determines in step S9 that the supply pressure of the high-pressure fuel is equal to or higher than the operating pressure of the safety valve 9 (YES in step S9), the controller 10 determines that there is an abnormality in the fuel pressure accumulator 4 and causes an abnormality. To terminate the control process. In this case, the safety valve 9 operates to discharge high-pressure fuel. As a result, the supply pressure of the high-pressure fuel becomes less than the operating pressure of the safety valve 9.
  • step S9 determines in step S9 that the supply pressure of the high-pressure fuel is less than the operating pressure of the safety valve 9 (the determination result in step S9 is NO)
  • the controller 10 performs the processing in steps S6 to S9 again.
  • the controller 10 further increases the supply pressure of the high-pressure fuel and maintains the pressure for X seconds. Subsequently, the controller 10 determines whether or not the actual engine speed is equal to or higher than the target engine speed. When the controller 10 determines that the actual engine speed is equal to or higher than the target engine speed, the controller 10 ends the control process. When the controller 10 determines that the actual engine speed is less than the target engine speed, It is determined whether the supply pressure is equal to or higher than the operating pressure of the safety valve 9. When the controller 10 determines that the supply pressure of the high-pressure fuel is equal to or higher than the operating pressure of the safety valve 9, the controller 10 notifies the abnormality and ends the control process. On the other hand, when the controller 10 determines that the supply pressure of the high-pressure fuel is lower than the operating pressure of the safety valve 9, the controller 10 performs the processes of steps S6 to S9 again.
  • the controller 10 increases the high-pressure fuel supply pressure while the high-pressure fuel supply pressure is lower than the operating pressure of the safety valve 9 when the actual engine speed does not reach the target rotation speed. Specifically, the controller 10 increases the high-pressure fuel supply pressure by 20 MPa every X seconds.
  • the fuel supply system 1 uses the supply pressure of the high-pressure fuel to remove impurities even if the operation of the fuel injection device 5 becomes defective due to the impurities in the fuel adhering to the injection valve 53. It becomes possible to remove from the injection valve 53.
  • the impurities removed from the injection valve 53 are melted by the temperature of the high-pressure fuel and injected from the injection hole 52 together with the high-pressure fuel, so that the lubricating operation of the injection valve 53 is restored. Therefore, the fuel supply system 1 of the present embodiment can solve the shortage of the injection amount even when the cause of the malfunction of the fuel injection device 5 is due to impurities in the fuel.
  • the fuel supply system 1 of the present embodiment increases the supply amount of the high-pressure fuel supplied to the fuel injection device 5 even when the injection time is the same as that of the conventional fuel supply system by increasing the supply pressure of the high-pressure fuel. . Therefore, in the fuel supply system 1 of the present embodiment, the injection amount is insufficient due to a high load on the engine 101, or the components of the fuel injection device 5 are worn and the amount of fuel leakage increases. Even when the injection amount is insufficient, the shortage of the injection amount can be solved as in the conventional fuel supply system.
  • the fuel supply system 1 includes an injection valve due to an insufficient amount of injection due to a high load on the engine 101, an injection amount insufficient due to an increase in the amount of fuel leakage, and an injection valve due to impurities in the fuel. It is possible to deal with any of the cases where the injection amount is insufficient due to the insufficient operation of 53. Therefore, the fuel supply system 1 of the present embodiment can increase the supply capability of the fuel supplied to the combustion chamber 102 of the engine 101 when the engine is started.
  • the fuel supply system 1 of the present embodiment uses the engine speed detection device 11 as a detection device that detects the operating state of the fuel injection device 5.
  • This engine speed detection device 11 is already mounted on the work vehicle. Therefore, the fuel supply system 1 according to the present embodiment does not require a new detection device for detecting the operating state of the fuel injection device 5, so that the system can be constructed at a reduced cost.
  • the fuel supply system 1 of the present embodiment uses the fuel pressure gauge 7 so that the supply pressure of the high-pressure fuel is less than an abnormal pressure (below the operating pressure of the safety valve 9) that may cause a failure in the fuel pressure accumulator 4.
  • the fuel supply system 1 of the present embodiment can prevent the fuel pressure accumulator 4 from being broken even if the supply pressure of the high-pressure fuel is increased, and the usability is improved.
  • the controller 10 when the controller 10 repeatedly performs the processing from step S6 to step S9, the controller 10 gradually increases the supply pressure of the high-pressure fuel every X seconds (stepwise). For this reason, it is possible to solve the shortage of injection amount without significantly reducing the fuel consumption as compared with the case where the supply pressure of the high-pressure fuel is rapidly increased. Therefore, the fuel supply system 1 of the present embodiment can increase the supply capability of the fuel supplied to the combustion chamber 102 of the engine 101 when the engine is started, and can suppress a decrease in fuel consumption.
  • the elapsed time is set on the horizontal axis, and the supply pressure of high-pressure fuel is set on the left vertical axis.
  • the operating pressure of the safety valve 9 is set to 110 MPa.
  • the actual rotational speed of the engine is set on the right vertical axis.
  • the target engine speed is set to 500 rpm.
  • Graph A shows the change over time of the supply pressure of the high-pressure fuel.
  • Graph B shows the change over time of the actual engine speed.
  • the controller 10 maintains the supply pressure (40 MPa) for X seconds when the supply pressure of the high-pressure fuel is initially 40 MPa when the engine is started.
  • controller 10 determines that the actual engine speed is less than the target engine speed after maintaining the high-pressure fuel supply pressure (40 MPa) for X seconds, the controller 10 increases the high-pressure fuel supply pressure to 60 MPa, Supply pressure (60 MPa) is maintained for X seconds.
  • the controller 10 determines that the actual engine speed is less than the target engine speed after maintaining the high-pressure fuel supply pressure (60 MPa) for X seconds, the controller 10 increases the high-pressure fuel supply pressure to 80 MPa, Supply pressure (80 MPa) is maintained for X seconds.
  • the controller 10 gradually increases the supply pressure of the high-pressure fuel every X seconds. Specifically, the controller 10 increases the high-pressure fuel supply pressure by 20 MPa every X seconds.
  • the controller 10 determines that the actual engine speed does not exceed the target engine speed even when the supply pressure of the high-pressure fuel is increased and the supply pressure is equal to or higher than the operating pressure (110 MPa) of the safety valve 9, the safety valve 9 operates to stop the pressure increase.
  • the controller 10 gradually increases the supply pressure of the high-pressure fuel every X seconds as in the case of FIG.
  • the controller 10 raises the supply pressure of the high-pressure fuel to 80 MPa and maintains it for X seconds
  • the actual engine speed exceeds the target engine speed (500 rpm).
  • the timing of the actual valve opening operation matches the control timing of the valve opening operation of the injection valve 53 by the controller 10, and the engine starts.
  • the controller 10 maintains the supply pressure (80 MPa) at this time for Y seconds, ends the control process at the time of engine start, and returns to the normal control process.
  • the normal control process is a fuel supply control process after engine startup (during engine operation).
  • the controller 10 maintains the supply pressure of the high-pressure fuel for a predetermined time (X seconds, Y seconds), so that even if the impurities attached to the injection valve 53 are sticky, the impurities are supplied to the high-pressure fuel. It can be reliably removed by the pressure. Therefore, the fuel supply system 1 according to the present embodiment can reliably eliminate the shortage of the injection amount at the time of starting the engine, and can reliably increase the supply capability of the fuel supplied to the combustion chamber of the engine.
  • the time for maintaining the supply pressure of the high-pressure fuel (X seconds, Y seconds) can be arbitrarily set.
  • the temperature of the high-pressure fuel supplied to the fuel injection device 5 is measured by the fuel thermometer 8, and the high-pressure fuel is supplied according to the change in the temperature of the high-pressure fuel obtained by the measurement.
  • a method for setting the time for maintaining the pressure will be described.
  • the controller 10 determines that the temperature of the high-pressure fuel has risen using the fuel thermometer 8, the controller 10 controls the operation of the fuel supply valve 6 to extend the time for maintaining the supply pressure of the high-pressure fuel. As a result, the supply amount of the high-pressure fuel supplied to the fuel injection device 5 increases, so that the shortage of the injection amount can be compensated.
  • the controller 10 determines that the temperature of the high pressure fuel has decreased using the fuel thermometer 8
  • the controller 10 controls the operation of the fuel supply valve 6 to shorten the time for maintaining the supply pressure of the high pressure fuel. Therefore, since the supply amount of the high-pressure fuel supplied to the fuel injection device 5 is suppressed, it is possible to suppress the high-pressure fuel from being unnecessarily injected.
  • the fuel supply system 1 changes the time for maintaining the supply pressure of the high-pressure fuel in accordance with the change in the temperature of the high-pressure fuel, thereby responding to the amount of leakage of the high-pressure fuel in the fuel injection device 5. It becomes possible to control the supply amount of the high-pressure fuel. Therefore, the fuel supply system 1 of the present embodiment can efficiently supply fuel to the combustion chamber of the engine.
  • the controller 10 may perform the following control process when the supply pressure of the high-pressure fuel exceeds the operating pressure of the safety valve 9 before the actual engine speed reaches the target engine speed.
  • the controller 10 determines from the fuel pressure gauge 7 that the supply pressure of the high pressure fuel has reached the operating pressure of the safety valve 9, the controller 10 controls the operation of the fuel supply valve 6 to lower the supply pressure of the high pressure fuel by one step. Maintain at supply pressure for additional X seconds.
  • the amount of high-pressure fuel supplied to the fuel injection device 5 is increased, so it is possible to cope with a case where the injection amount is insufficient due to a high load on the engine and a case where the injection amount is insufficient due to an increase in the leakage amount of high-pressure fuel. can do.
  • the fuel pressure gauge 7 and the fuel thermometer 8 are connected to the fuel pressure accumulator 4.
  • the fuel pressure gauge 7 and the fuel thermometer 8 are connected to the second supply pipe 22 or the third supply. It may be connected to the tube 23.
  • the engine speed detection device 11 is used as a detection device for detecting the operation state of the fuel injection device 5.
  • this detection device is not limited to the engine speed detection device 11.
  • a detection device that detects the voltage of the battery of the cell motor may be used. When this detection device is used, it is determined whether or not the operation of the fuel injection device 5 is defective from the change in the voltage of the battery before and after the start of the cell motor.
  • the operating pressure of the safety valve 9 is used as an abnormal pressure that may cause a failure in the fuel pressure accumulator 4.
  • the abnormal pressure is not limited to the operating pressure of the safety valve 9.
  • the fuel supply system may set the abnormal pressure in the controller 10 without using the safety valve 9.
  • the controller 10 controls the operation of the fuel supply valve 6 to lower the supply pressure when the supply pressure of the high-pressure fuel reaches an abnormal pressure. Thereby, the fuel supply system can prevent a failure of the fuel pressure accumulator 4.

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

Abstract

Provided is a fuel supplying system capable of improving the supply capacity of fuel supplied to an engine combustion chamber during engine startup. A controller for the fuel supplying system determines at engine startup whether the actual engine speed is equal to or greater than a target speed by way of an engine speed detecting device (step S5). When the actual engine speed is determined to be less than the target speed (determination result of step S5 is no), the controller increases the supply pressure of fuel under high pressure to be supplied to a fuel injection device by way of increasing the supply pressure of the fuel being supplied to a high pressure pump by controlling the operation of a fuel supply valve (step S6).

Description

燃料供給システムFuel supply system
　本発明は、例えば油圧ショベル等の作業車両のエンジンに使用される燃料供給システムに関するものである。 The present invention relates to a fuel supply system used for an engine of a work vehicle such as a hydraulic excavator.
　油圧ショベル等の作業車両のエンジンに使用される燃料噴射装置は、一般に、燃料を噴射するための噴口と、この噴口を開閉する噴射弁とを備えている。また、この燃料噴射装置を使用して、エンジンの燃焼室へ燃料を供給するシステム（燃料供給システム）が知られている（例えば特許文献１参照）。 2. Description of the Related Art A fuel injection device used for an engine of a work vehicle such as a hydraulic excavator generally includes a nozzle for injecting fuel and an injection valve for opening and closing the nozzle. Further, a system (fuel supply system) that supplies fuel to a combustion chamber of an engine using this fuel injection device is known (see, for example, Patent Document 1).
　特許文献１の燃料供給システムでは、高圧ポンプが燃料タンクから燃料を吸い上げて加圧して高圧燃料にする。高圧ポンプは、高圧燃料を燃料蓄圧装置へ供給する。燃料蓄圧装置は、高圧ポンプから供給された高圧燃料を高圧状態のままで蓄えて、高圧燃料の一部を燃料噴射装置へ供給する。燃料噴射装置では、噴射弁が開動作して噴孔が開くことにより高圧燃料をエンジンの燃焼室へ噴射する。 In the fuel supply system of Patent Document 1, a high-pressure pump sucks up fuel from a fuel tank and pressurizes it into high-pressure fuel. The high pressure pump supplies high pressure fuel to the fuel pressure accumulator. The fuel pressure accumulator stores the high-pressure fuel supplied from the high-pressure pump in a high-pressure state, and supplies a part of the high-pressure fuel to the fuel injection device. In the fuel injection device, the high pressure fuel is injected into the combustion chamber of the engine by opening the injection valve and opening the injection hole.
　また、特許文献１で開示されているような従来の燃料供給システムでは、エンジンの始動時に燃料噴射装置の動作が不良であるか否かを判断している。そして、従来の燃料供給システムは、燃料噴射装置の動作が不良であると判断した場合は、噴射量が不足していると判断して燃料噴射装置に供給する高圧燃料の供給時間を増やして高圧燃料の供給量を増やす。これにより従来の燃料供給システムは、噴射量の不足を解消するようにしている。 Further, in the conventional fuel supply system as disclosed in Patent Document 1, it is determined whether or not the operation of the fuel injection device is defective when the engine is started. When the conventional fuel supply system determines that the operation of the fuel injection device is defective, it determines that the injection amount is insufficient and increases the supply time of the high-pressure fuel supplied to the fuel injection device to increase the high pressure. Increase fuel supply. As a result, the conventional fuel supply system solves the shortage of the injection amount.
　したがって、従来の燃料供給システムは、エンジンにかかる負荷が高くなることによる噴射量の不足の場合や、燃料噴射装置の構成部品が磨耗して高圧燃料の漏れ量が増加することによる噴射量の不足の場合に対応することが可能になっている。 Therefore, in the conventional fuel supply system, the injection amount is insufficient when the load on the engine becomes high, or when the components of the fuel injection device wear out and the leakage amount of high-pressure fuel increases. It is possible to cope with this case.
特許第３８５５４７１号公報Japanese Patent No. 3855471
　しかしながら、燃料噴射装置の動作不良の原因は、燃料中の不純物による場合がある。この場合を具体的に説明する。燃料噴射装置の噴孔が燃料中の不純物により詰まると、この不純物が噴射弁に付着する。その結果、噴射弁は潤滑に動作しなくなり、燃料噴射装置の動作が不良となる。 However, the cause of the malfunction of the fuel injection device may be due to impurities in the fuel. This case will be specifically described. When the nozzle hole of the fuel injection device is clogged with impurities in the fuel, the impurities adhere to the injection valve. As a result, the injection valve does not operate smoothly, and the operation of the fuel injection device becomes defective.
　この場合でも従来の燃料供給システムは、燃料噴射装置に供給する高圧燃料の供給時間を増やすだけである。したがって、燃料噴射装置は、噴射弁の潤滑な動作が回復しないので噴射量の不足が解消されず、エンジンの燃焼室に十分な燃料を供給することができない。 Even in this case, the conventional fuel supply system only increases the supply time of the high-pressure fuel supplied to the fuel injection device. Therefore, the fuel injection device does not recover the lubrication operation of the injection valve, so that the shortage of the injection amount is not solved and sufficient fuel cannot be supplied to the combustion chamber of the engine.
　本発明は以上の問題を鑑みて成されたものであり、エンジン始動時にエンジンの燃焼室に供給する燃料の供給能力を上げることができる燃料供給システムを提供することを目的とする。 The present invention has been made in view of the above problems, and an object of the present invention is to provide a fuel supply system capable of increasing the supply capacity of fuel supplied to a combustion chamber of an engine when the engine is started.
　本発明者等は、鋭意研究の結果、前記課題を解決するために以下のような燃料供給システムを採用した。 As a result of earnest research, the present inventors have adopted the following fuel supply system in order to solve the above problems.
　本発明の燃料供給システムは、
　燃料タンクに第１の供給管で接続され、前記燃料タンクから前記第１の供給管を介して前記燃料タンク中の燃料を吸い上げて加圧して高圧燃料にする高圧ポンプと、
　前記高圧ポンプに第２の供給管で接続され、前記高圧ポンプから供給される前記高圧燃料を高圧状態のままで蓄える燃料蓄圧装置と、
　前記燃料畜圧装置に第３の供給管で接続され、前記燃料蓄圧装置から前記高圧燃料が供給される噴射弁および当該噴射弁の開動作により開いて前記高圧燃料をエンジンの燃焼室へ噴射する噴孔を有する燃料噴射装置と、
　前記第１の供給管に接続され、前記高圧ポンプに供給される前記燃料の供給圧力を制御することにより前記燃料噴射装置へ供給する前記高圧燃料の供給圧力を制御する燃料供給バルブと、
　前記燃料噴射装置の動作状態を検出する検出装置と、
　前記検出装置の検出結果に応じて前記噴射弁の動作および前記燃料供給バルブの動作を制御するコントローラと、
　前記コントローラに接続され、前記エンジンのキースイッチの入力の有無を検出するキースイッチ入力検出装置とを備え、
　前記コントローラは、前記キースイッチ入力検出装置により前記キースイッチの入力があると判断した場合には、前記検出装置により前記燃料噴射装置の動作が不良であるか否かを判断し、前記燃料噴射装置の動作が不良であると判断した場合には、前記燃料供給バルブの動作を制御して前記高圧ポンプに供給される前記燃料の供給圧力を上げることにより前記高圧燃料の供給圧力を上げることを特徴とする。 The fuel supply system of the present invention comprises:
A high-pressure pump connected to the fuel tank by a first supply pipe, and sucking up the fuel in the fuel tank from the fuel tank via the first supply pipe and pressurizing the fuel tank into a high-pressure fuel;
A fuel pressure accumulator connected to the high pressure pump by a second supply pipe and storing the high pressure fuel supplied from the high pressure pump in a high pressure state;
An injection valve that is connected to the fuel pressure storage device by a third supply pipe and is supplied with the high-pressure fuel from the fuel pressure storage device, and is opened by opening the injection valve to inject the high-pressure fuel into the combustion chamber of the engine. A fuel injection device having an injection hole;
A fuel supply valve connected to the first supply pipe and controlling the supply pressure of the high-pressure fuel supplied to the fuel injection device by controlling the supply pressure of the fuel supplied to the high-pressure pump;
A detection device for detecting an operating state of the fuel injection device;
A controller for controlling the operation of the injection valve and the operation of the fuel supply valve according to the detection result of the detection device;
A key switch input detection device that is connected to the controller and detects the presence or absence of an input of the key switch of the engine;
When the controller determines that there is an input from the key switch by the key switch input detection device, the controller determines whether the operation of the fuel injection device is defective by the detection device, and the fuel injection device When it is determined that the operation of the high pressure fuel is poor, the operation of the fuel supply valve is controlled to increase the supply pressure of the high pressure fuel by increasing the supply pressure of the fuel supplied to the high pressure pump. And
　本発明の燃料供給システムは、燃料噴射装置の動作が不良であると判断した場合に、燃料噴射装置へ供給する高圧燃料の供給圧力を上げるようにした。これにより、本発明の燃料供給システムは、噴射弁に燃料中の不純物が付着することにより燃料噴射装置の動作が不良となっても、高圧燃料の供給圧力を利用して不純物を噴射弁から除去することが可能になる。噴射弁から除去された不純物は、高圧燃料の温度により溶けて高圧燃料とともに噴孔から噴射されるので、噴射弁の潤滑な動作が回復する。よって、本発明の燃料供給システムは、燃料噴射装置の動作不良の原因が燃料中の不純物による場合でも、噴射量の不足を解消することができる。 The fuel supply system of the present invention increases the supply pressure of the high-pressure fuel supplied to the fuel injection device when it is determined that the operation of the fuel injection device is defective. As a result, the fuel supply system of the present invention removes impurities from the injection valve using the supply pressure of the high-pressure fuel even if the fuel injection device becomes defective due to adhesion of impurities in the fuel to the injection valve. It becomes possible to do. The impurities removed from the injection valve are melted by the temperature of the high-pressure fuel and injected together with the high-pressure fuel from the injection hole, so that the lubricating operation of the injection valve is restored. Therefore, the fuel supply system of the present invention can solve the shortage of the injection amount even when the cause of the malfunction of the fuel injection device is due to impurities in the fuel.
　また、本発明の燃料供給システムは、高圧燃料の供給圧力を上げることにより、噴射時間が従来の燃料供給システムと同じでも、燃料噴射装置へ供給する高圧燃料の供給量が増加する。したがって、本発明の燃料供給システムは、エンジンにかかる負荷が高いことによる噴射量の不足の場合や、燃料噴射装置の構成部品が磨耗して高圧燃料の漏れ量が増加することによる噴射量の不足の場合でも、従来の燃料供給システムと同様に噴射量の不足を解消することができる。よって、本発明の燃料供給システムは、エンジン始動時にエンジンの燃焼室への燃料の供給能力を上げることができる。 In the fuel supply system of the present invention, the supply pressure of the high-pressure fuel supplied to the fuel injection device is increased by increasing the supply pressure of the high-pressure fuel even if the injection time is the same as the conventional fuel supply system. Therefore, the fuel supply system of the present invention has a shortage of injection amount due to a shortage of injection amount due to a high load on the engine or due to wear of components of the fuel injection device and an increase in the amount of high-pressure fuel leakage. Even in this case, the shortage of the injection amount can be resolved as in the conventional fuel supply system. Therefore, the fuel supply system of the present invention can increase the fuel supply capacity to the combustion chamber of the engine when the engine is started.
本発明の一実施の形態を示す燃料供給システムのブロック図である。1 is a block diagram of a fuel supply system showing an embodiment of the present invention. 同実施の形態の燃料供給システムのコントローラによるエンジン始動時の燃料の供給制御処理を示すフローチャートである。It is a flowchart which shows the fuel supply control process at the time of engine starting by the controller of the fuel supply system of the embodiment. 同実施の形態においてエンジン始動時のエンジンの実回転数と高圧燃料の供給圧力との関係を示す図である。It is a figure which shows the relationship between the actual rotation speed of the engine at the time of engine starting in this Embodiment, and the supply pressure of a high pressure fuel. 同実施の形態においてエンジン始動時のエンジンの実回転数と高圧燃料の供給圧力との関係を示す図である。It is a figure which shows the relationship between the actual rotation speed of the engine at the time of engine starting in this Embodiment, and the supply pressure of a high pressure fuel.
　以下、本発明の実施の形態を図にしたがって説明する。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
　図１は、本発明の一実施の形態を示す燃料供給システム１のブロック図である。この燃料供給システム１は、油圧ショベル等の作業車両のエンジンに使用される。図１において、実線の流れは燃料の流れを示し、点線の流れは制御信号の流れを示す。 FIG. 1 is a block diagram of a fuel supply system 1 showing an embodiment of the present invention. The fuel supply system 1 is used for an engine of a work vehicle such as a hydraulic excavator. In FIG. 1, a solid line flow indicates a fuel flow, and a dotted line flow indicates a control signal flow.
　最初に、燃料供給システム１の全体の構成を説明する。この燃料供給システム１は、燃料タンク２、高圧ポンプ３、燃料蓄圧装置４、燃料噴射装置５を備えている。 First, the overall configuration of the fuel supply system 1 will be described. The fuel supply system 1 includes a fuel tank 2, a high-pressure pump 3, a fuel pressure accumulation device 4, and a fuel injection device 5.
　燃料タンク２は、その内部にエンジンの燃料が蓄えられている。高圧ポンプ３は、燃料タンク２に第１の供給管２１で接続されている。この高圧ポンプ３は、燃料タンク２から第１の供給管２１を介して燃料タンク２中の燃料を吸い上げて加圧することにより高圧燃料にして、この高圧燃料を燃料蓄圧装置４に供給するものである。 The fuel tank 2 stores the engine fuel. The high-pressure pump 3 is connected to the fuel tank 2 by a first supply pipe 21. The high-pressure pump 3 sucks up and pressurizes the fuel in the fuel tank 2 from the fuel tank 2 through the first supply pipe 21 to form high-pressure fuel, and supplies the high-pressure fuel to the fuel pressure accumulator 4. is there.
　燃料蓄圧装置４は、高圧ポンプ３に第２の供給管２２で接続されている。この燃料蓄圧装置４は、高圧ポンプ３から第２の供給管２２を介して供給される高圧燃料を高圧状態のままで蓄えて、高圧燃料の一部を燃料噴射装置へ供給するものである。 The fuel pressure accumulator 4 is connected to the high-pressure pump 3 through a second supply pipe 22. The fuel accumulator 4 stores the high-pressure fuel supplied from the high-pressure pump 3 via the second supply pipe 22 in a high-pressure state and supplies a part of the high-pressure fuel to the fuel injection device.
　燃料噴射装置５は、燃料蓄圧装置４から供給される高圧燃料をエンジン１０１の燃焼室１０２へ噴射するものである。この燃料噴射装置５は、燃料蓄圧装置４に第３の供給管２３で接続されている。燃料噴射装置５は、本体５１に第３の供給管２３が接続されている。本体５１の先端には噴孔５２が設けられている。本体５１の内部には噴射弁５３が設けられている。この噴射弁５３は、噴孔５２を開閉するものである。燃料噴射装置５は、噴射弁５３が開動作して噴孔５２が開くことにより高圧燃料をエンジン１０１の燃焼室１０２に噴射する。 The fuel injection device 5 injects high-pressure fuel supplied from the fuel accumulator 4 into the combustion chamber 102 of the engine 101. This fuel injection device 5 is connected to the fuel pressure accumulator 4 by a third supply pipe 23. In the fuel injection device 5, the third supply pipe 23 is connected to the main body 51. A nozzle hole 52 is provided at the tip of the main body 51. An injection valve 53 is provided inside the main body 51. This injection valve 53 opens and closes the injection hole 52. The fuel injection device 5 injects high-pressure fuel into the combustion chamber 102 of the engine 101 by opening the injection valve 53 and opening the injection hole 52.
　また、本体５１には、燃料の戻し管（図示せず）が接続されている。この戻し管は、燃料タンク２に接続されている。燃料噴射装置５から漏れた燃料は、この戻し管を介して燃料タンク２に戻される。 Further, a fuel return pipe (not shown) is connected to the main body 51. This return pipe is connected to the fuel tank 2. The fuel leaking from the fuel injection device 5 is returned to the fuel tank 2 through this return pipe.
　第１の供給管２１には、燃料供給バルブ６が接続されている。この燃料供給バルブ６は、高圧ポンプ３に供給される燃料の供給圧力を制御することにより燃料噴射装置５に供給される高圧燃料の供給圧力を制御するものである。 The fuel supply valve 6 is connected to the first supply pipe 21. The fuel supply valve 6 controls the supply pressure of the high-pressure fuel supplied to the fuel injection device 5 by controlling the supply pressure of the fuel supplied to the high-pressure pump 3.
　燃料蓄圧装置４には、燃料圧力計７と燃料温度計８とが接続されている。燃料圧力計７は、燃料蓄圧装置４に蓄えられている高圧燃料の圧力（高圧燃料の供給圧力）を測定するものである。燃料温度計８は、燃料蓄圧装置４に蓄えられている高圧燃料の温度を測定するものである。 A fuel pressure gauge 7 and a fuel thermometer 8 are connected to the fuel pressure accumulator 4. The fuel pressure gauge 7 measures the pressure of the high pressure fuel stored in the fuel pressure accumulator 4 (supply pressure of the high pressure fuel). The fuel thermometer 8 measures the temperature of the high-pressure fuel stored in the fuel pressure accumulator 4.
　さらに燃料蓄圧装置４には、安全弁９が接続されている。この安全弁９は、高圧燃料の供給圧力が上がり過ぎて燃料蓄圧装置４が故障するのを防ぐものである。この内容を具体的に説明する。安全弁９は、高圧燃料の供給圧力が安全弁９の動作圧力以上になると高圧燃料を排出して高圧燃料の供給圧力を下げる。この安全弁９の動作圧力は、高圧燃料の供給圧力が燃料蓄圧装置に故障が生じる可能性がある異常圧力である。 Furthermore, a safety valve 9 is connected to the fuel pressure accumulator 4. The safety valve 9 prevents the fuel pressure accumulating device 4 from being damaged due to an excessive increase in the supply pressure of the high-pressure fuel. This content will be specifically described. The safety valve 9 discharges the high-pressure fuel and lowers the supply pressure of the high-pressure fuel when the supply pressure of the high-pressure fuel exceeds the operating pressure of the safety valve 9. The operating pressure of the safety valve 9 is an abnormal pressure that may cause a failure in the fuel accumulator due to the supply pressure of the high-pressure fuel.
　また、燃料供給システム１は、コントローラ１０を備えている。このコントローラ１０は、高圧ポンプ３の駆動の制御、燃料噴射装置５の噴射弁５３の動作の制御、燃料供給バルブ６の動作の制御を行うものである。 In addition, the fuel supply system 1 includes a controller 10. This controller 10 controls the drive of the high-pressure pump 3, controls the operation of the injection valve 53 of the fuel injection device 5, and controls the operation of the fuel supply valve 6.
　コントローラ１０には、エンジンの実回転数を検出するエンジン回転数検出装置１１が接続されている。また、コントローラ１０には、エンジンのキースイッチの入力の有無を検出するキースイッチ入力検出装置１２が接続されている。 The controller 10 is connected to an engine speed detector 11 that detects the actual engine speed. The controller 10 is connected to a key switch input detection device 12 that detects the presence or absence of an input of an engine key switch.
　次に、燃料供給システム１によるエンジン運転中の燃料の供給制御処理を説明する。燃料供給システム１は、コントローラ１０により高圧ポンプ３が駆動し、高圧ポンプ３は燃料タンク２中の燃料を吸い上げて加圧して高圧燃料にする。高圧ポンプ３は、この高圧燃料を燃料蓄圧装置４へ供給する。燃料蓄圧装置４は、高圧ポンプ３から供給される高圧燃料を高圧状態のままで蓄えて高圧燃料の一部を燃料噴射装置５の噴射弁５３に供給する。コントローラ１０は、噴射弁５３を開動作して噴孔５２を開ける。これにより、噴孔５２からエンジン１０１の燃焼室１０２へ高圧燃料が噴射される。 Next, fuel supply control processing during engine operation by the fuel supply system 1 will be described. In the fuel supply system 1, the high-pressure pump 3 is driven by the controller 10, and the high-pressure pump 3 sucks up the fuel in the fuel tank 2 and pressurizes it to make high-pressure fuel. The high pressure pump 3 supplies the high pressure fuel to the fuel pressure accumulator 4. The fuel accumulator 4 stores the high-pressure fuel supplied from the high-pressure pump 3 in a high-pressure state and supplies a part of the high-pressure fuel to the injection valve 53 of the fuel injector 5. The controller 10 opens the injection hole 52 by opening the injection valve 53. As a result, high-pressure fuel is injected from the injection hole 52 into the combustion chamber 102 of the engine 101.
　また、コントローラ１０は、エンジン回転数検出装置１１から検出されるエンジンの実回転数に応じて噴射弁５３の動作と燃料供給バルブ６の動作を制御することにより、噴射と噴射量を制御している。 Further, the controller 10 controls the injection and the injection amount by controlling the operation of the injection valve 53 and the operation of the fuel supply valve 6 according to the actual engine speed detected from the engine speed detection device 11. Yes.
　次に、図２を用いて、コントローラ１０によるエンジン始動時の燃料の供給制御処理について説明する。 Next, the fuel supply control process at the time of engine start by the controller 10 will be described with reference to FIG.
（ステップＳ１）
　コントローラ１０は、キースイッチ入力検出装置１２により、キースイッチの入力の有無を判断する。 (Step S1)
The controller 10 uses the key switch input detection device 12 to determine whether or not the key switch is input.
（ステップＳ２）
　コントローラ１０は、ステップＳ１においてキースイッチの入力が有ると判断した場合には（ステップＳ１の判断結果がＹＥＳ）、燃料圧力計７により、高圧燃料の供給圧力が高圧ポンプ３の動作圧力以上であるか否かを判断する。 (Step S2)
If the controller 10 determines in step S1 that the key switch is input (the determination result in step S1 is YES), the fuel pressure gauge 7 causes the high-pressure fuel supply pressure to be equal to or higher than the operating pressure of the high-pressure pump 3. Determine whether or not.
　高圧ポンプ３の動作圧力とは、高圧ポンプ３の動作に最低限必要な圧力である。高圧ポンプ３の動作圧力の具体的な値は、例えば２０ＭＰａである。 The operating pressure of the high pressure pump 3 is the minimum pressure necessary for the operation of the high pressure pump 3. A specific value of the operating pressure of the high-pressure pump 3 is, for example, 20 MPa.
　コントローラ１０は、ステップＳ２において高圧燃料の供給圧力が高圧ポンプ３の動作圧力未満の場合には（ステップＳ２の判断結果がＮＯ）、高圧ポンプ３が動作していないと判断して異常を報知し（ステップＳ１０）、制御処理を終了する。 When the supply pressure of the high-pressure fuel is lower than the operating pressure of the high-pressure pump 3 in step S2 (the determination result in step S2 is NO), the controller 10 determines that the high-pressure pump 3 is not operating and reports an abnormality. (Step S10), the control process is terminated.
　（ステップＳ３）
　コントローラ１０は、高圧燃料の供給圧力が高圧ポンプ３の動作圧力以上の場合には（ステップＳ２の判断結果がＹＥＳ）、燃料圧力計７により高圧燃料の供給圧力が安全弁９の動作圧力以上か否かを判断する。 (Step S3)
When the high-pressure fuel supply pressure is equal to or higher than the operating pressure of the high-pressure pump 3 (YES in step S2), the controller 10 determines whether the high-pressure fuel supply pressure is equal to or higher than the operating pressure of the safety valve 9 by the fuel pressure gauge 7. Determine whether.
　コントローラ１０は、ステップＳ３において高圧燃料の供給圧力が安全弁９の動作圧力以上であると判断した場合には（ステップＳ３の判断結果がＹＥＳ）、燃料蓄圧装置４に異常があると判断して異常を報知し（ステップＳ１０）、制御処理を終了する。また、この場合には安全弁９が動作して高圧燃料が排出される。これにより高圧燃料の供給圧力が安全弁９の動作圧力未満になる。 When the controller 10 determines in step S3 that the supply pressure of the high-pressure fuel is equal to or higher than the operating pressure of the safety valve 9 (the determination result in step S3 is YES), the controller 10 determines that there is an abnormality in the fuel pressure accumulator 4 and abnormal. (Step S10), and the control process is terminated. In this case, the safety valve 9 operates to discharge high-pressure fuel. As a result, the supply pressure of the high-pressure fuel becomes less than the operating pressure of the safety valve 9.
（ステップＳ４）
　コントローラ１０は、ステップＳ３において高圧燃料の供給圧力が安全弁９の動作圧力未満であると判断した場合には（ステップＳ３の判断結果がＮＯ）、燃料供給バルブ６の動作状態を所定時間（Ｘ秒間）維持することにより、高圧燃料の供給圧力を所定時間（Ｘ秒間）維持する。 (Step S4)
If the controller 10 determines in step S3 that the supply pressure of the high-pressure fuel is lower than the operating pressure of the safety valve 9 (the determination result in step S3 is NO), the controller 10 changes the operating state of the fuel supply valve 6 for a predetermined time (X seconds). ) To maintain the supply pressure of the high-pressure fuel for a predetermined time (X seconds).
（ステップＳ５）
　次に、コントローラ１０は、エンジン回転数検出装置１１により、エンジンの実回転数が目標回転数以上であるか否かを判断する。 (Step S5)
Next, the controller 10 uses the engine speed detection device 11 to determine whether or not the actual engine speed is equal to or higher than the target speed.
　エンジンの目標回転数は、エンジンの始動に最低限必要なエンジンの実回転数である。この目標回転数は、燃料噴射装置５の動作が不良であるか否かの判断の目安となる。目標回転数の具体的な値は、例えば５００ｒｐｍである。 The engine target speed is the minimum engine speed required for starting the engine. This target rotational speed is a standard for determining whether or not the operation of the fuel injection device 5 is defective. A specific value of the target rotational speed is, for example, 500 rpm.
　コントローラ１０は、ステップＳ５においてエンジンの実回転数が目標回転数以上であると判断した場合には（ステップＳ５の判断結果がＹＥＳ）、エンジンが始動したと判断して制御処理を終了する。 If the controller 10 determines in step S5 that the actual engine speed is greater than or equal to the target engine speed (the determination result in step S5 is YES), the controller 10 determines that the engine has started and ends the control process.
（ステップＳ６）
　コントローラ１０は、ステップＳ５においてエンジンの実回転数が目標回転数未満であると判断した場合には（ステップＳ５の判断結果がＮＯ）、燃料供給バルブ６の動作を制御して高圧燃料の供給圧力を上げる。 (Step S6)
When the controller 10 determines in step S5 that the actual engine speed is less than the target engine speed (NO in step S5), the controller 10 controls the operation of the fuel supply valve 6 to supply the high-pressure fuel supply pressure. Raise.
（ステップＳ７）
　続いてコントローラ１０は、燃料供給バルブ６の動作状態を所定時間（Ｘ秒間）維持することにより、高圧燃料の供給圧力を所定時間（Ｘ秒間）維持する。 (Step S7)
Subsequently, the controller 10 maintains the operating state of the fuel supply valve 6 for a predetermined time (X seconds), thereby maintaining the supply pressure of the high-pressure fuel for a predetermined time (X seconds).
（ステップＳ８）
　次に、コントローラ１０は、エンジン回転数検出装置１１により、エンジンの実回転数が目標回転数以上であるか否かを判断する。この目標回転数は、ステップＳ５で設定した目標回転数と同じである。 (Step S8)
Next, the controller 10 uses the engine speed detection device 11 to determine whether or not the actual engine speed is equal to or higher than the target speed. This target rotational speed is the same as the target rotational speed set in step S5.
　コントローラ１０は、ステップＳ８においてエンジンの実回転数が目標回転数以上であると判断した場合には（ステップＳ８の判断結果がＹＥＳ）、エンジンが始動したと判断して制御処理を終了する。 If the controller 10 determines in step S8 that the actual engine speed is equal to or higher than the target engine speed (YES in step S8), the controller 10 determines that the engine has started and ends the control process.
（ステップＳ９）
　コントローラ１０は、ステップＳ８においてエンジンの実回転数が目標回転数未満であると判断した場合には（ステップＳ８の判断結果がＮＯ）、燃料圧力計７により高圧燃料の供給圧力が安全弁９の動作圧力以上か否かを判断する。 (Step S9)
When the controller 10 determines in step S8 that the actual engine speed is less than the target engine speed (the determination result in step S8 is NO), the fuel pressure gauge 7 causes the supply pressure of the high-pressure fuel to operate the safety valve 9. Judge whether pressure is over or not.
（ステップＳ１０）
　コントローラ１０は、ステップＳ９において高圧燃料の供給圧力が安全弁９の動作圧力以上であると判断した場合には（ステップＳ９の判断結果がＹＥＳ）、燃料蓄圧装置４に異常があると判断して異常を報知して制御処理を終了する。また、この場合には安全弁９が動作して高圧燃料が排出される。これにより高圧燃料の供給圧力が安全弁９の動作圧力未満になる。 (Step S10)
If the controller 10 determines in step S9 that the supply pressure of the high-pressure fuel is equal to or higher than the operating pressure of the safety valve 9 (YES in step S9), the controller 10 determines that there is an abnormality in the fuel pressure accumulator 4 and causes an abnormality. To terminate the control process. In this case, the safety valve 9 operates to discharge high-pressure fuel. As a result, the supply pressure of the high-pressure fuel becomes less than the operating pressure of the safety valve 9.
　コントローラ１０は、ステップＳ９において高圧燃料の供給圧力が安全弁９の動作圧力未満であると判断した場合には（ステップＳ９の判断結果がＮＯ）、ステップＳ６～ステップＳ９の処理を再度行う。 If the controller 10 determines in step S9 that the supply pressure of the high-pressure fuel is less than the operating pressure of the safety valve 9 (the determination result in step S9 is NO), the controller 10 performs the processing in steps S6 to S9 again.
　この処理を説明すると、コントローラ１０は、高圧燃料の供給圧力をさらに上げて、その圧力をＸ秒間維持する。続いてコントローラ１０は、エンジンの実回転数が目標回転数以上であるか否かを判断する。コントローラ１０は、エンジンの実回転数が目標回転数以上であると判断した場合には制御処理を終了し、エンジンの実回転数が目標回転数未満であると判断した場合には、高圧燃料の供給圧力が安全弁９の動作圧力以上か否かを判断する。コントローラ１０は、高圧燃料の供給圧力が安全弁９の動作圧力以上であると判断した場合には、異常を報知して制御処理を終了する。また、コントローラ１０は、高圧燃料の供給圧力が安全弁９の動作圧力未満であると判断した場合には、ステップＳ６～ステップＳ９の処理を再度行う。 Describing this process, the controller 10 further increases the supply pressure of the high-pressure fuel and maintains the pressure for X seconds. Subsequently, the controller 10 determines whether or not the actual engine speed is equal to or higher than the target engine speed. When the controller 10 determines that the actual engine speed is equal to or higher than the target engine speed, the controller 10 ends the control process. When the controller 10 determines that the actual engine speed is less than the target engine speed, It is determined whether the supply pressure is equal to or higher than the operating pressure of the safety valve 9. When the controller 10 determines that the supply pressure of the high-pressure fuel is equal to or higher than the operating pressure of the safety valve 9, the controller 10 notifies the abnormality and ends the control process. On the other hand, when the controller 10 determines that the supply pressure of the high-pressure fuel is lower than the operating pressure of the safety valve 9, the controller 10 performs the processes of steps S6 to S9 again.
　つまり、コントローラ１０は、エンジンの実回転数が目標回転数に到達しない場合に、高圧燃料の供給圧力が安全弁９の動作圧力未満である間は、高圧燃料の供給圧力を上げている。具体的には、コントローラ１０は高圧燃料の供給圧力をＸ秒毎に２０ＭＰａ上げている。 That is, the controller 10 increases the high-pressure fuel supply pressure while the high-pressure fuel supply pressure is lower than the operating pressure of the safety valve 9 when the actual engine speed does not reach the target rotation speed. Specifically, the controller 10 increases the high-pressure fuel supply pressure by 20 MPa every X seconds.
　したがって、本実施の形態の燃料供給システム１は、噴射弁５３に燃料中の不純物が付着することにより燃料噴射装置５の動作が不良になっても、高圧燃料の供給圧力を利用して不純物を噴射弁５３から除去することが可能になる。噴射弁５３から除去された不純物は、高圧燃料の温度により溶けて高圧燃料とともに噴孔５２から噴射されるので、噴射弁５３の潤滑な動作が回復する。よって、本実施の形態の燃料供給システム１は、燃料噴射装置５の動作不良の原因が燃料中の不純物による場合でも、噴射量の不足を解消できる。 Therefore, the fuel supply system 1 according to the present embodiment uses the supply pressure of the high-pressure fuel to remove impurities even if the operation of the fuel injection device 5 becomes defective due to the impurities in the fuel adhering to the injection valve 53. It becomes possible to remove from the injection valve 53. The impurities removed from the injection valve 53 are melted by the temperature of the high-pressure fuel and injected from the injection hole 52 together with the high-pressure fuel, so that the lubricating operation of the injection valve 53 is restored. Therefore, the fuel supply system 1 of the present embodiment can solve the shortage of the injection amount even when the cause of the malfunction of the fuel injection device 5 is due to impurities in the fuel.
　また、本実施の形態の燃料供給システム１は、高圧燃料の供給圧力を上げることにより、噴射時間が従来の燃料供給システムと同じでも、燃料噴射装置５へ供給する高圧燃料の供給量が増加する。したがって、本実施の形態の燃料供給システム１は、エンジン１０１にかかる負荷が高いことによる噴射量の不足の場合や、燃料噴射装置５の構成部品が磨耗して燃料の漏れ量が増加することによる噴射量の不足の場合でも、従来の燃料供給システムと同様に噴射量の不足を解消することができる。 Further, the fuel supply system 1 of the present embodiment increases the supply amount of the high-pressure fuel supplied to the fuel injection device 5 even when the injection time is the same as that of the conventional fuel supply system by increasing the supply pressure of the high-pressure fuel. . Therefore, in the fuel supply system 1 of the present embodiment, the injection amount is insufficient due to a high load on the engine 101, or the components of the fuel injection device 5 are worn and the amount of fuel leakage increases. Even when the injection amount is insufficient, the shortage of the injection amount can be solved as in the conventional fuel supply system.
　つまり、本実施の形態の燃料供給システム１は、エンジン１０１にかかる負荷が高いことによる噴射量不足の場合と、燃料の漏れ量の増加による噴射量不足の場合と、燃料中の不純物による噴射弁５３の動作不足による噴射量不足の場合のいずれの場合にも対応することができる。よって、本実施の形態の燃料供給システム１は、エンジン始動時にエンジン１０１の燃焼室１０２に供給する燃料の供給能力を上げることができる。 That is, the fuel supply system 1 according to the present embodiment includes an injection valve due to an insufficient amount of injection due to a high load on the engine 101, an injection amount insufficient due to an increase in the amount of fuel leakage, and an injection valve due to impurities in the fuel. It is possible to deal with any of the cases where the injection amount is insufficient due to the insufficient operation of 53. Therefore, the fuel supply system 1 of the present embodiment can increase the supply capability of the fuel supplied to the combustion chamber 102 of the engine 101 when the engine is started.
　また、本実施の形態の燃料供給システム１は、燃料噴射装置５の動作状態を検出する検出装置としてエンジン回転数検出装置１１を使用した。このエンジン回転数検出装置１１は、作業車両に既に搭載されているものである。したがって、本実施の形態の燃料供給システム１は、燃料噴射装置５の動作状態を検出するために新たな検出装置を用意する必要がないので、コストを抑えてシステムを構築することができる。 Also, the fuel supply system 1 of the present embodiment uses the engine speed detection device 11 as a detection device that detects the operating state of the fuel injection device 5. This engine speed detection device 11 is already mounted on the work vehicle. Therefore, the fuel supply system 1 according to the present embodiment does not require a new detection device for detecting the operating state of the fuel injection device 5, so that the system can be constructed at a reduced cost.
　さらに、本実施の形態の燃料供給システム１は燃料圧力計７を使用し、高圧燃料の供給圧力が燃料蓄圧装置４に故障が生じる可能性がある異常圧力未満（安全弁９の動作圧力未満）にあると判断した場合に高圧燃料の供給圧力をさらに上げるようにした。したがって、本実施の形態の燃料供給システム１は、高圧燃料の供給圧力を上げても燃料蓄圧装置４の故障を防ぐことができ、使い勝手が上がる。 Further, the fuel supply system 1 of the present embodiment uses the fuel pressure gauge 7 so that the supply pressure of the high-pressure fuel is less than an abnormal pressure (below the operating pressure of the safety valve 9) that may cause a failure in the fuel pressure accumulator 4. When it was determined that there was, the supply pressure of high-pressure fuel was further increased. Therefore, the fuel supply system 1 of the present embodiment can prevent the fuel pressure accumulator 4 from being broken even if the supply pressure of the high-pressure fuel is increased, and the usability is improved.
　また、コントローラ１０は、ステップＳ６～ステップＳ９の処理を繰り返して行うときには、高圧燃料の供給圧力をＸ秒毎に徐々に（段階的に）上げている。このため、高圧燃料の供給圧力を急激に上げる場合に比べて燃費を大幅に下げずに噴射量の不足を解消することが可能になる。よって、本実施の形態の燃料供給システム１は、エンジン始動時にエンジン１０１の燃焼室１０２に供給する燃料の供給能力を上げるとともに、燃費の低下を抑えることができる。 In addition, when the controller 10 repeatedly performs the processing from step S6 to step S9, the controller 10 gradually increases the supply pressure of the high-pressure fuel every X seconds (stepwise). For this reason, it is possible to solve the shortage of injection amount without significantly reducing the fuel consumption as compared with the case where the supply pressure of the high-pressure fuel is rapidly increased. Therefore, the fuel supply system 1 of the present embodiment can increase the supply capability of the fuel supplied to the combustion chamber 102 of the engine 101 when the engine is started, and can suppress a decrease in fuel consumption.
　次に、高圧燃料の供給圧力を徐々に上げる制御の具体的な内容を図３と図４を用いて説明する。図３と図４では、横軸に経過時間が設定され、左の縦軸に高圧燃料の供給圧力が設定されている。安全弁９の動作圧力は１１０ＭＰａに設定されている。右の縦軸にはエンジンの実回転数が設定されている。エンジンの目標回転数は５００ｒｐｍに設定されている。グラフＡは、高圧燃料の供給圧力の時間変化を示すものである。グラフＢは、エンジンの実回転数の時間変化を示すものである。なお、図３と図４で示されている数値は、一例として挙げているものである。 Next, the specific contents of the control for gradually increasing the supply pressure of the high-pressure fuel will be described with reference to FIGS. 3 and 4, the elapsed time is set on the horizontal axis, and the supply pressure of high-pressure fuel is set on the left vertical axis. The operating pressure of the safety valve 9 is set to 110 MPa. The actual rotational speed of the engine is set on the right vertical axis. The target engine speed is set to 500 rpm. Graph A shows the change over time of the supply pressure of the high-pressure fuel. Graph B shows the change over time of the actual engine speed. The numerical values shown in FIGS. 3 and 4 are given as an example.
　最初に図３の場合について説明する。コントローラ１０は、グラフＡで示すように、エンジン始動時において最初に高圧燃料の供給圧力が４０ＭＰａの場合には、その供給圧力（４０ＭＰａ）をＸ秒間維持する。 First, the case of FIG. 3 will be described. As shown in graph A, the controller 10 maintains the supply pressure (40 MPa) for X seconds when the supply pressure of the high-pressure fuel is initially 40 MPa when the engine is started.
　コントローラ１０は、高圧燃料の供給圧力（４０ＭＰａ）をＸ秒間維持した後に、エンジンの実回転数が目標回転数未満であると判断した場合には、高圧燃料の供給圧力を６０ＭＰａに上げて、その供給圧力（６０ＭＰａ）をＸ秒間維持する。 If the controller 10 determines that the actual engine speed is less than the target engine speed after maintaining the high-pressure fuel supply pressure (40 MPa) for X seconds, the controller 10 increases the high-pressure fuel supply pressure to 60 MPa, Supply pressure (60 MPa) is maintained for X seconds.
　コントローラ１０は、高圧燃料の供給圧力（６０ＭＰａ）をＸ秒間維持した後に、エンジンの実回転数が目標回転数未満であると判断した場合には、高圧燃料の供給圧力を８０ＭＰａに上げて、その供給圧力（８０ＭＰａ）をＸ秒間維持する。 When the controller 10 determines that the actual engine speed is less than the target engine speed after maintaining the high-pressure fuel supply pressure (60 MPa) for X seconds, the controller 10 increases the high-pressure fuel supply pressure to 80 MPa, Supply pressure (80 MPa) is maintained for X seconds.
　このようにコントローラ１０は高圧燃料の供給圧力をＸ秒毎に徐々に上げている。具体的には、コントローラ１０は高圧燃料の供給圧力をＸ秒毎に２０ＭＰａ上げている。そして、コントローラ１０は、高圧燃料の供給圧力を上げてもエンジンの実回転数が目標回転数を超えず、供給圧力が安全弁９の動作圧力（１１０ＭＰａ）以上であると判断した場合には、安全弁９が動作して圧力の上昇が止まる。 Thus, the controller 10 gradually increases the supply pressure of the high-pressure fuel every X seconds. Specifically, the controller 10 increases the high-pressure fuel supply pressure by 20 MPa every X seconds. When the controller 10 determines that the actual engine speed does not exceed the target engine speed even when the supply pressure of the high-pressure fuel is increased and the supply pressure is equal to or higher than the operating pressure (110 MPa) of the safety valve 9, the safety valve 9 operates to stop the pressure increase.
　次に図４の場合について説明する。コントローラ１０は、図３の場合と同様に高圧燃料の供給圧力をＸ秒毎に徐々に上げる。コントローラ１０は、高圧燃料の供給圧力を８０ＭＰａに上げてＸ秒間維持したときにエンジンの実回転数が目標回転数（５００ｒｐｍ）を超える。このときには、高圧燃料の供給圧力によって、噴射弁５３に付着している不純物が除去される。その結果、コントローラ１０による噴射弁５３の開弁動作の制御タイミングに実際の開弁動作のタイミングが合ってエンジンが始動する。 Next, the case of FIG. 4 will be described. The controller 10 gradually increases the supply pressure of the high-pressure fuel every X seconds as in the case of FIG. When the controller 10 raises the supply pressure of the high-pressure fuel to 80 MPa and maintains it for X seconds, the actual engine speed exceeds the target engine speed (500 rpm). At this time, impurities adhering to the injection valve 53 are removed by the supply pressure of the high-pressure fuel. As a result, the timing of the actual valve opening operation matches the control timing of the valve opening operation of the injection valve 53 by the controller 10, and the engine starts.
　なお、コントローラ１０は、このときの供給圧力（８０ＭＰａ）をＹ秒間維持してエンジン始動時の制御処理を終了し、通常の制御処理に戻る。通常の制御処理は、エンジン始動後（エンジン運転中）の燃料の供給制御処理である。 The controller 10 maintains the supply pressure (80 MPa) at this time for Y seconds, ends the control process at the time of engine start, and returns to the normal control process. The normal control process is a fuel supply control process after engine startup (during engine operation).
　このようにコントローラ１０は、高圧燃料の供給圧力を所定時間（Ｘ秒間、Ｙ秒間）維持することにより、噴射弁５３に付着している不純物が粘着性のものでも、その不純物を高圧燃料の供給圧力により確実に除去することが可能になる。よって、本実施の形態の燃料供給システム１は、エンジン始動時の噴射量の不足を確実に解消することができ、エンジンの燃焼室に供給する燃料の供給能力を確実に上げることができる。 Thus, the controller 10 maintains the supply pressure of the high-pressure fuel for a predetermined time (X seconds, Y seconds), so that even if the impurities attached to the injection valve 53 are sticky, the impurities are supplied to the high-pressure fuel. It can be reliably removed by the pressure. Therefore, the fuel supply system 1 according to the present embodiment can reliably eliminate the shortage of the injection amount at the time of starting the engine, and can reliably increase the supply capability of the fuel supplied to the combustion chamber of the engine.
　なお、高圧燃料の供給圧力を維持する時間（Ｘ秒、Ｙ秒）は任意に設定することが可能である。本実施の形態の燃料供給システム１では、燃料噴射装置５に供給される高圧燃料の温度を燃料温度計８により測定し、測定により得られた高圧燃料の温度の変化に応じて高圧燃料の供給圧力を維持する時間を設定する方法を説明する。 The time for maintaining the supply pressure of the high-pressure fuel (X seconds, Y seconds) can be arbitrarily set. In the fuel supply system 1 of the present embodiment, the temperature of the high-pressure fuel supplied to the fuel injection device 5 is measured by the fuel thermometer 8, and the high-pressure fuel is supplied according to the change in the temperature of the high-pressure fuel obtained by the measurement. A method for setting the time for maintaining the pressure will be described.
　高圧燃料の温度が上がると高圧燃料の粘度が下がるため、燃料噴射装置５では高圧燃料の漏れ量が増加して噴射量が不足する。したがって、コントローラ１０は、燃料温度計８を使用して高圧燃料の温度が上がったと判断した場合には、燃料供給バルブ６の動作を制御して高圧燃料の供給圧力を維持する時間を長くする。これにより燃料噴射装置５に供給される高圧燃料の供給量が増加するので、噴射量の不足を補うことが可能になる。 When the temperature of the high-pressure fuel rises, the viscosity of the high-pressure fuel decreases. Therefore, in the fuel injection device 5, the amount of high-pressure fuel leakage increases and the injection amount becomes insufficient. Therefore, when the controller 10 determines that the temperature of the high-pressure fuel has risen using the fuel thermometer 8, the controller 10 controls the operation of the fuel supply valve 6 to extend the time for maintaining the supply pressure of the high-pressure fuel. As a result, the supply amount of the high-pressure fuel supplied to the fuel injection device 5 increases, so that the shortage of the injection amount can be compensated.
　また、高圧燃料の温度が下がると高圧燃料の粘度が上がるため、燃料噴射装置５では高圧燃料の漏れ量が減少して高圧燃料が無駄に噴射される。したがって、コントローラ１０は、燃料温度計８を使用して高圧燃料の温度が下がったと判断した場合には、燃料供給バルブ６の動作を制御して高圧燃料の供給圧力を維持する時間を短くする。これにより、燃料噴射装置５に供給される高圧燃料の供給量が抑えられるので、高圧燃料が無駄に噴射されるのを抑えることができる。 In addition, since the viscosity of the high-pressure fuel increases as the temperature of the high-pressure fuel decreases, the amount of leakage of the high-pressure fuel is reduced in the fuel injection device 5 and the high-pressure fuel is wasted. Therefore, when the controller 10 determines that the temperature of the high pressure fuel has decreased using the fuel thermometer 8, the controller 10 controls the operation of the fuel supply valve 6 to shorten the time for maintaining the supply pressure of the high pressure fuel. Thereby, since the supply amount of the high-pressure fuel supplied to the fuel injection device 5 is suppressed, it is possible to suppress the high-pressure fuel from being unnecessarily injected.
　このように本実施の形態の燃料供給システム１は、高圧燃料の温度の変化に応じて高圧燃料の供給圧力を維持する時間を変えることにより、燃料噴射装置５において高圧燃料の漏れ量に応じた高圧燃料の供給量の制御を行うことが可能になる。よって、本実施の形態の燃料供給システム１は、エンジンの燃焼室へ燃料を効率よく供給することができる。 As described above, the fuel supply system 1 according to the present embodiment changes the time for maintaining the supply pressure of the high-pressure fuel in accordance with the change in the temperature of the high-pressure fuel, thereby responding to the amount of leakage of the high-pressure fuel in the fuel injection device 5. It becomes possible to control the supply amount of the high-pressure fuel. Therefore, the fuel supply system 1 of the present embodiment can efficiently supply fuel to the combustion chamber of the engine.
　また、コントローラ１０は、エンジンの実回転数が目標回転数に到達する前に高圧燃料の供給圧力が安全弁９の動作圧力を超える場合には、次のような制御処理を行っても良い。コントローラ１０は、燃料圧力計７から高圧燃料の供給圧力が安全弁９の動作圧力に到達したと判断したときに、燃料供給バルブ６の動作を制御して高圧燃料の供給圧力を一段階下げ、その供給圧力でさらにＸ秒間維持する。これにより、燃料噴射装置５に供給する高圧燃料の供給量が増加するので、エンジンにかかる負荷が高いことによる噴射量不足の場合と、高圧燃料の漏れ量の増加による噴射量不足の場合に対応することができる。 Further, the controller 10 may perform the following control process when the supply pressure of the high-pressure fuel exceeds the operating pressure of the safety valve 9 before the actual engine speed reaches the target engine speed. When the controller 10 determines from the fuel pressure gauge 7 that the supply pressure of the high pressure fuel has reached the operating pressure of the safety valve 9, the controller 10 controls the operation of the fuel supply valve 6 to lower the supply pressure of the high pressure fuel by one step. Maintain at supply pressure for additional X seconds. As a result, the amount of high-pressure fuel supplied to the fuel injection device 5 is increased, so it is possible to cope with a case where the injection amount is insufficient due to a high load on the engine and a case where the injection amount is insufficient due to an increase in the leakage amount of high-pressure fuel. can do.
　以上、本発明にかかる実施の形態を例示したが、この実施の形態は本発明の内容を限定するものではない。また、本発明の請求項の範囲を逸脱しない範囲であれば、各種の変更等は可能である。 As mentioned above, although embodiment concerning this invention was illustrated, this embodiment does not limit the content of this invention. Various modifications can be made without departing from the scope of the claims of the present invention.
　例えば、本実施の形態の燃料供給システム１では、燃料圧力計７と燃料温度計８を燃料蓄圧装置４に接続した。しかし、高圧ポンプ３と燃料噴射装置５との間は、高圧燃料の供給圧力と温度はそれぞれ同じであるため、燃料圧力計７と燃料温度計８を第２の供給管２２や第３の供給管２３に接続しても良い。 For example, in the fuel supply system 1 of the present embodiment, the fuel pressure gauge 7 and the fuel thermometer 8 are connected to the fuel pressure accumulator 4. However, since the supply pressure and temperature of the high-pressure fuel are the same between the high-pressure pump 3 and the fuel injection device 5, the fuel pressure gauge 7 and the fuel thermometer 8 are connected to the second supply pipe 22 or the third supply. It may be connected to the tube 23.
　また、本実施の形態の燃料供給システム１では、燃料噴射装置５の動作状態を検出する検出装置としてエンジン回転数検出装置１１を使用した。しかし、この検出装置はエンジン回転数検出装置１１に限定されない。その他の検出装置としては、セルモーターのバッテリーの電圧を検出する検出装置を使用しても良い。この検出装置を使用する場合には、セルモーター始動前後のバッテリーの電圧の変化から燃料噴射装置５の動作が不良であるか否かを判断する。 Further, in the fuel supply system 1 of the present embodiment, the engine speed detection device 11 is used as a detection device for detecting the operation state of the fuel injection device 5. However, this detection device is not limited to the engine speed detection device 11. As another detection device, a detection device that detects the voltage of the battery of the cell motor may be used. When this detection device is used, it is determined whether or not the operation of the fuel injection device 5 is defective from the change in the voltage of the battery before and after the start of the cell motor.
　また、本実施の形態の燃料供給システム１では、燃料蓄圧装置４に故障が生じる可能性がある異常圧力として安全弁９の動作圧力を使用した。しかし、異常圧力は、安全弁９の動作圧力に限定されない。例えば、燃料供給システムは、安全弁９を使用せずに、異常圧力をコントローラ１０に設定しても良い。コントローラ１０は、高圧燃料の供給圧力が異常圧力に到達したときに燃料供給バルブ６の動作を制御して供給圧力を下げる。これにより燃料供給システムは、燃料蓄圧装置４の故障を防ぐことができる。 Also, in the fuel supply system 1 of the present embodiment, the operating pressure of the safety valve 9 is used as an abnormal pressure that may cause a failure in the fuel pressure accumulator 4. However, the abnormal pressure is not limited to the operating pressure of the safety valve 9. For example, the fuel supply system may set the abnormal pressure in the controller 10 without using the safety valve 9. The controller 10 controls the operation of the fuel supply valve 6 to lower the supply pressure when the supply pressure of the high-pressure fuel reaches an abnormal pressure. Thereby, the fuel supply system can prevent a failure of the fuel pressure accumulator 4.

Claims (4)

  1. 　燃料タンクに第１の供給管で接続され、前記燃料タンクから前記第１の供給管を介して前記燃料タンク中の燃料を吸い上げて加圧して高圧燃料にする高圧ポンプと、
    　前記高圧ポンプに第２の供給管で接続され、前記高圧ポンプから供給される前記高圧燃料を高圧状態のままで蓄える燃料蓄圧装置と、
    　前記燃料畜圧装置に第３の供給管で接続され、前記燃料蓄圧装置から前記高圧燃料が供給される噴射弁および当該噴射弁の開動作により開いて前記高圧燃料をエンジンの燃焼室へ噴射する噴孔を有する燃料噴射装置と、
    　前記第１の供給管に接続され、前記高圧ポンプに供給される前記燃料の供給圧力を制御することにより前記燃料噴射装置へ供給する前記高圧燃料の供給圧力を制御する燃料供給バルブと、
    　前記燃料噴射装置の動作状態を検出する検出装置と、
    　前記検出装置の検出結果に応じて前記噴射弁の動作および前記燃料供給バルブの動作を制御するコントローラと、
    　前記コントローラに接続され、前記エンジンのキースイッチの入力の有無を検出するキースイッチ入力検出装置とを備え、
    　前記コントローラは、前記キースイッチ入力検出装置により前記キースイッチの入力があると判断した場合には、前記検出装置により前記燃料噴射装置の動作が不良であるか否かを判断し、前記燃料噴射装置の動作が不良であると判断した場合には、前記燃料供給バルブの動作を制御して前記高圧ポンプに供給される前記燃料の供給圧力を上げることにより前記高圧燃料の供給圧力を上げることを特徴とする燃料供給システム。     A high-pressure pump connected to the fuel tank by a first supply pipe, and sucking up the fuel in the fuel tank from the fuel tank via the first supply pipe and pressurizing the fuel tank into a high-pressure fuel;
    A fuel pressure accumulator connected to the high pressure pump by a second supply pipe and storing the high pressure fuel supplied from the high pressure pump in a high pressure state;
    An injection valve that is connected to the fuel pressure storage device by a third supply pipe and is supplied with the high-pressure fuel from the fuel pressure storage device, and is opened by opening the injection valve to inject the high-pressure fuel into the combustion chamber of the engine. A fuel injection device having an injection hole;
    A fuel supply valve connected to the first supply pipe and controlling the supply pressure of the high-pressure fuel supplied to the fuel injection device by controlling the supply pressure of the fuel supplied to the high-pressure pump;
    A detection device for detecting an operating state of the fuel injection device;
    A controller for controlling the operation of the injection valve and the operation of the fuel supply valve according to the detection result of the detection device;
    A key switch input detection device that is connected to the controller and detects the presence or absence of an input of the key switch of the engine;
    When the controller determines that there is an input from the key switch by the key switch input detection device, the controller determines whether the operation of the fuel injection device is defective by the detection device, and the fuel injection device When it is determined that the operation of the high pressure fuel is poor, the operation of the fuel supply valve is controlled to increase the supply pressure of the high pressure fuel by increasing the supply pressure of the fuel supplied to the high pressure pump. And fuel supply system.
  2. 　請求項１に記載の燃料供給システムにおいて、
    　前記検出装置は、前記エンジンの実回転数を検出するエンジン回転数検出装置を備え、
    　前記コントローラは、前記エンジン回転数検出装置により検出される前記エンジンの実回転数が前記エンジンの始動に必要な目標回転数以上であるか否かにより前記燃料噴射装置の動作が不良であるか否かを判断し、前記エンジンの実回転数が前記目標回転数未満であることにより前記燃料噴射装置の動作が不良であると判断した場合には、前記燃料供給バルブの動作を制御して前記高圧燃料の供給圧力を上げることを特徴とする燃料供給システム。     The fuel supply system according to claim 1, wherein
    The detection device includes an engine rotation speed detection device that detects an actual rotation speed of the engine,
    The controller determines whether or not the operation of the fuel injection device is defective depending on whether or not the actual engine speed detected by the engine speed detector is equal to or higher than a target engine speed required for starting the engine. If the actual rotational speed of the engine is less than the target rotational speed and it is determined that the operation of the fuel injection device is defective, the operation of the fuel supply valve is controlled to control the high pressure A fuel supply system, characterized by increasing a fuel supply pressure.
  3. 　請求項２に記載の燃料供給システムにおいて、
    　前記高圧燃料の供給圧力を測定する燃料圧力計を備え、
    　前記コントローラは、前記高圧燃料の供給圧力を上げた後に、前記エンジン回転数検出装置により前記燃料噴射装置の動作が不良であるか否かを判断して前記燃料噴射装置の動作が不良であると判断した場合には、前記燃料圧力計により前記高圧燃料の供給圧力が前記燃料蓄圧装置に故障が生じる可能性がある異常圧力以上であるか否かを判断し、前記高圧燃料の供給圧力が前記異常圧力未満であると判断した場合には、前記燃料供給バルブの動作を制御して前記高圧燃料の供給圧力を上げることを特徴とする燃料供給システム。     The fuel supply system according to claim 2, wherein
    A fuel pressure gauge for measuring the supply pressure of the high-pressure fuel;
    The controller, after increasing the supply pressure of the high-pressure fuel, determines whether or not the operation of the fuel injection device is defective by the engine speed detection device and determines that the operation of the fuel injection device is defective. When the determination is made, the fuel pressure gauge determines whether or not the supply pressure of the high-pressure fuel is equal to or higher than an abnormal pressure that may cause a failure of the fuel pressure accumulator, and the supply pressure of the high-pressure fuel is When it is determined that the pressure is less than the abnormal pressure, the fuel supply system increases the supply pressure of the high-pressure fuel by controlling the operation of the fuel supply valve.
  4. 　請求項１～請求項３のいずれか１項に記載の燃料供給システムにおいて、
    　前記コントローラは、前記高圧燃料の供給圧力を徐々に上げることを特徴とする燃料供給システム。     The fuel supply system according to any one of claims 1 to 3,
    The fuel supply system, wherein the controller gradually increases a supply pressure of the high-pressure fuel.
PCT/JP2014/053756 2014-02-18 2014-02-18 Fuel supplying system WO2015125208A1 (en)

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JP2003278620A (en) * 2002-01-21 2003-10-02 Denso Corp Accumulator fuel injection device
JP2006183469A (en) * 2004-12-24 2006-07-13 Denso Corp Fuel injector
JP2006342685A (en) * 2005-06-07 2006-12-21 Toyota Motor Corp Control device of internal combustion engine
JP2009008057A (en) * 2007-06-29 2009-01-15 Denso Corp Fuel injection device for internal combustion engine of vehicle
JP2013096335A (en) * 2011-11-02 2013-05-20 Bosch Corp Deposit detection method and common rail type fuel injection control apparatus

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002089344A (en) * 2000-09-07 2002-03-27 Nippon Soken Inc Aging effect judgement device for fuel injection device
JP2003278620A (en) * 2002-01-21 2003-10-02 Denso Corp Accumulator fuel injection device
JP2006183469A (en) * 2004-12-24 2006-07-13 Denso Corp Fuel injector
JP2006342685A (en) * 2005-06-07 2006-12-21 Toyota Motor Corp Control device of internal combustion engine
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