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
  • 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
  • F02M61/168—Assembling; Disassembling; Manufacturing; Adjusting
• • 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
  • F02D41/20—Output circuits, e.g. for controlling currents in command coils
  • F02D41/2096—Output circuits, e.g. for controlling currents in command coils for controlling piezoelectric injectors
• • 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
  • F02M51/00—Fuel-injection apparatus characterised by being operated electrically
  • F02M51/06—Injectors peculiar thereto with means directly operating the valve needle
  • F02M51/0603—Injectors peculiar thereto with means directly operating the valve needle using piezoelectric or magnetostrictive operating means
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10N30/00—Piezoelectric or electrostrictive devices
  • H10N30/80—Constructional details
  • H10N30/802—Circuitry or processes for operating piezoelectric or electrostrictive devices not otherwise provided for, e.g. drive circuits
• • 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
  • F02D41/20—Output circuits, e.g. for controlling currents in command coils
  • F02D2041/202—Output circuits, e.g. for controlling currents in command coils characterised by the control of the circuit
  • F02D2041/2051—Output circuits, e.g. for controlling currents in command coils characterised by the control of the circuit using voltage control
• • 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
  • F02D41/20—Output circuits, e.g. for controlling currents in command coils
  • F02D2041/202—Output circuits, e.g. for controlling currents in command coils characterised by the control of the circuit
  • F02D2041/2055—Output circuits, e.g. for controlling currents in command coils characterised by the control of the circuit with means for determining actual opening or closing time
• • 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
  • F02D41/20—Output circuits, e.g. for controlling currents in command coils
  • F02D2041/202—Output circuits, e.g. for controlling currents in command coils characterised by the control of the circuit
  • F02D2041/2058—Output circuits, e.g. for controlling currents in command coils characterised by the control of the circuit using information of the actual current value

Definitions

• the present invention relates to a method for controlling a fuel injector in accordance with claim 1 .
• the invention also concerns a control arrangement as defined in another independent claim and a method for upgrading such a control arrangement.
• each fuel injector comprises an injection needle, which opens and closes fluid communication between the cylinder and a fuel source.
• each fuel injector has been provided with a solenoid actuator. The fuel injector is actuated when current is fed into the coil of the actuator.
• Such conventional fuel injectors have only an on/off function, i.e. the injector can be either in an open or in a closed state and it is not possible to select intermediate states where the injector would be only partly open.
• Fuel injectors can also be provided with piezoelectric actuators, which offer a more precise control of the fuel injection.
• Piezoelectric actuators utilize piezoelectric materials, where a voltage signal is used to deform the material and the opening of the injector depends on the voltage fed into the actuator. Since the piezoelectric actuators need a voltage signal, control units designed for controlling conventional fuel injectors are not suitable for controlling piezoelectric actuators. This is a problem especially when upgrading engines equipped with conventional fuel injectors by replacing the fuel injectors with injectors that are provided with piezoelectric actuators, since also the control unit needs to be replaced.
• each cylinder may be provided with two or more fuel injectors, of which some are actuated by a solenoid actuator and some by a piezoelectric actuator. In that case different control units are needed for different actuators.
• An object of the present invention is to provide an improved method for controlling a fuel injector of a piston engine, as defined in claim 1 .
• Another object of the invention is to provide an improved control arrangement for a fuel injector of a piston engine and a method for upgrading such a control arrangement, as defined in the other independent claims.
• the method according to the invention comprises the steps of producing a current signal carrying the information of the desired fuel injection timing and duration, and transforming the current signal into a voltage signal for controlling a piezoelectric actuator of a fuel injector.
• the control arrangement comprises a fuel injection control unit that is configured to produce a current signal carrying the information of the desired fuel injection timing and duration, the arrangement comprising means for transforming the current signal into a voltage signal for controlling a piezoelectric actuator of a fuel injector.
• the control arrangement is provided with means for transforming a current signal into a voltage signal for controlling a piezoelectric actuator of a fuel injector.
• the same control unit can be used for controlling both solenoid-actuated fuel injectors and piezoelectrically actuated fuel injectors.
• conventional fuel injectors can be replaced by fuel injectors that are provided with piezoelectric actuators without a need to replace fuel injection control units.
• Fig. 1 shows schematically a control arrangement for a fuel injector
• Fig. 2A shows a current signal for injection control
• Fig. 2B shows the state of a solenoid-actuated injector corresponding the current signal of Fig. 2A
• Fig. 2C shows a voltage signal corresponding the current signal of Fig. 2A
• Fig. 2D shows the state of a piezoelectrically actuated injector corresponding the voltage signal of Fig. 2C
• Fig. 3A shows another current signal for injection control
• Fig. 3B shows a voltage signal corresponding the current signal of Fig. 3A
• Fig. 3C shows the state of a piezoelectrically actuated injector corresponding the voltage signal of Fig. 3B.
• FIG 1 is shown schematically a control arrangement for a fuel injector 10 of a piston engine.
• the engine can be a large internal combustion engine, such as a main or an auxiliary engine of a ship or an engine that is used at a power plant for producing electricity.
• the control arrangement controls a single fuel injector 10, but preferably each cylinder of the engine is provided with at least one fuel injector 10, which is controlled in the same way.
• Each cylinder of the engine could also be provided with more than one fuel injectors, in which case one or more of the fuel injectors can be controlled in the same way as the fuel injector 10 of figure 1 , and one or more of the fuel injectors can be controlled in a different way.
• each cylinder can be provided with separate fuel injectors for gaseous fuel, liquid pilot fuel and liquid main fuel.
• the fuel injector 10 injects the fuel into the cylinder or into a pre-combustion chamber.
• the fuel injector 10 of figure 1 is actuated by a piezoelectric actuator 5.
• the piezoelectric actuator 5 contains piezoelectric material that can convert a voltage signal into a physical movement. The position of the piezoelectric actuator 5 depends on the voltage.
• the piezoelectric actuator 5 is a stack actuator producing a linear movement.
• the control arrangement according to an embodiment of the invention comprises a fuel injection control unit 1 , which can control fuel injection timing and duration.
• the fuel injection control unit 1 is configured to produce a current signal, which can be used to directly control a conventional fuel injector, where current flowing through the coil of a solenoid-actuator switches the fuel injector from a closed state to an open state where the fuel injection takes place.
• the same fuel injection control unit 1 can control all the fuel injectors 10 of the engine, but the fuel injection control unit 1 needs to produce an individual control signal for each cylinder of the engine, unless the fuel injection takes place in more than one cylinder at the same time.
• Fig. 2A shows a typical current signal of the fuel injection control unit 1 and Fig. 2B shows the corresponding state of a solenoid-actuated fuel injector.
• a certain threshold current is exceeded, the fuel injector is switched to the open state and the fuel injector remains open until the current drops below the threshold value.
• the fuel injector is either in the open or in the closed state and does not take any intermediate position. Fuel injection rate shaping is thus not possible and the amount of the injected fuel depends on the duration of the period over which the fuel injector is kept open.
• the control arrangement is provided with a piezo control unit 2.
• the piezo control unit 2 is configured to receive a current signal from the fuel injection control unit 1 and process it in order to control a piezoelectric actuator 5.
• the piezo control unit 2 is a module that is separate from the fuel injection control unit 1 .
• the piezo control unit 2 is connected to a first voltage source 3 and to a second voltage source 4.
• the first voltage source 3 produces a first voltage and the second voltage source 4 produces a second voltage.
• the first voltage is in the range of 700 to 1300 V and the second voltage is in the range of 100 to 300 V.
• the piezo control unit 2 comprises a conversion unit 2a, an amplification unit 2b and a measurement unit 2c.
• the current signal from the fuel injection control unit 1 is received by the conversion unit 2a and processed in the piezo control unit 2 in three stages.
• the magnitude of the current of the input signal is in the range of 0 to 5 A.
• the current signal is transformed into a voltage signal in the conversion unit 2a.
• the conversion unit 2a can be a conventional current-to-voltage converter, which takes the current signal as an input and outputs a voltage signal where the magnitude of the voltage is dependent on the magnitude of the current of the input signal.
• the amplification unit 2b receives as an input the voltage signal from the conversion unit 2a.
• the voltage signal is amplified and used as a set point for the injection control.
• the amplification unit 2b comprises a closed loop control for the voltage signal. The control is based on the feedback received from the measurement unit 2c in the third stage.
• the measurement unit 2c monitors the voltage and the current of the amplified voltage signal. In a calibrated piezoelectric actuator 5, the voltage over the actuator 5 also tells the position of the actuator 5.
• the measurement unit 2c monitors the voltage over the piezoelectric actuator 5 and sends the position information to the fuel injection control unit 1 via a first feedback line 7.
• the needle lift of the fuel injector 10 can be determined.
• the data of the voltage measurement of the amplified voltage signal is sent to the fuel injection control unit 1 via a second feedback line 8 and the data of the current measurement of the amplified voltage signal is sent to the fuel injection control unit 1 via a third feedback line 9.
• the information from the measurement unit 2c can be used for tuning the control signal produced by the fuel injection control unit 1 .
• Figure 2C shows a voltage signal corresponding the current signal of Fig. 2A. As can be seen in the figure, the shape of the voltage signal corresponds the shape of the current signal.
• Figure 2D shows the corresponding position of the piezoelectric actuator 5. The position of the fuel injector 10 follows the position of the actuator 5.
• Figure 3A shows an alternative current signal 3A and figures 3B and 3C show the corresponding voltage signal and the position of the piezoelectric actuator 5, respectively.
• a different current signal can be used to produce a different opening profile of the fuel injector 10.
• a more precise control of the fuel injection rate can thus be achieved than would be possible with a solenoid actuator.
• the control arrangement according to the invention is suitable especially for engine upgrades. Solenoid actuators can be replaced by piezoelectric actuators without a need to replace the fuel injection control unit 1 . With a piezo control unit 2, the current signal produced by the fuel injection control unit 1 can be converted in such a way that the piezoelectric actuators 5 can be controlled.
• the invention is useful also in multi-fuel engines.
• the same fuel injection control unit 1 can be used for controlling all the fuel injectors.
• the fuel injectors for gaseous fuel can be actuated by solenoid actuators, whereas the pilot fuel injectors and the injectors for the liquid main fuel can be piezoelectrically actuated.

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

Applications Claiming Priority (2)

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• 2015
  • 2015-11-24 CN CN201580065963.2A patent/CN107002582B/zh active Active
  • 2015-11-24 EP EP15804864.5A patent/EP3227549A1/en not_active Withdrawn
  • 2015-11-24 KR KR1020177015087A patent/KR101953045B1/ko active IP Right Grant
  • 2015-11-24 WO PCT/FI2015/050816 patent/WO2016087710A1/en active Application Filing

Patent Citations (2)

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