EP2930346A1 - Verfahren zur steuerung und diagnose bezüglich des betriebs eines kraftstoffeinspritzers - Google Patents

Verfahren zur steuerung und diagnose bezüglich des betriebs eines kraftstoffeinspritzers Download PDF

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Publication number
EP2930346A1
EP2930346A1 EP15159321.7A EP15159321A EP2930346A1 EP 2930346 A1 EP2930346 A1 EP 2930346A1 EP 15159321 A EP15159321 A EP 15159321A EP 2930346 A1 EP2930346 A1 EP 2930346A1
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EP
European Patent Office
Prior art keywords
valve
actuator
needle
fuel injector
contact
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP15159321.7A
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English (en)
French (fr)
Inventor
Andrew Hargreaves
Michael Cooke
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Delphi International Operations Luxembourg SARL
Original Assignee
Delphi International Operations Luxembourg SARL
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Delphi International Operations Luxembourg SARL filed Critical Delphi International Operations Luxembourg SARL
Publication of EP2930346A1 publication Critical patent/EP2930346A1/de
Withdrawn legal-status Critical Current

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    • 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
    • F02M61/167—Means for compensating clearance or thermal expansion
    • 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
    • F02M57/00—Fuel-injectors combined or associated with other devices
    • F02M57/005—Fuel-injectors combined or associated with other devices the devices being sensors
    • 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
    • F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
    • F02M2200/21—Fuel-injection apparatus with piezoelectric or magnetostrictive elements
    • 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
    • F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
    • F02M2200/24—Fuel-injection apparatus with sensors
    • 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
    • F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
    • F02M2200/70—Linkage between actuator and actuated element, e.g. between piezoelectric actuator and needle valve or pump plunger
    • F02M2200/701—Linkage between actuator and actuated element, e.g. between piezoelectric actuator and needle valve or pump plunger mechanical

Definitions

  • the invention relates to fuel injectors for delivering fuel into a combustion chamber such as a cylinder of an internal combustion engine. It relates in particular, but not exclusively, to fuel injectors including piezoelectric actuators used to control movement of a needle in an injector valve.
  • piezoelectric actuators is known as an alternative to solenoids for controlling injections in a fuel injector.
  • a stack of piezoelectric elements can be arranged to control fuel pressure within an injector fuel chamber so as to consequentially control the movement of an injector needle away from a valve seat so as to inject fuel.
  • the distal portion of the piezo stack abuts/contacts the proximal (upper end) portion of an injector needle (typically via intermediate components), and actuation of the piezoelectric stack/actuator pushes against the needle to force the needle downward so as to displace the needle away from its seat to dispense fuel.
  • fuel may be dispensed on retraction of the needle due to retraction of the piezoelectric stack. In all cases, the needle needs to be in contact with the end of the stack (albeit sometimes via intermediary components) during fuel injection process.
  • injector Components of the injector have different thermal expansion/contraction characteristics. Often there are also variations in manufacturing or measurement tolerances, clamping/clamp nut load tolerances, and there is also valve seat wear. For these reasons injector designs provide for a gap between the end of the stack./actuator (including any associated components) and the needle(respective needle components), which is required for a fully discharged piezo stack to overcome such variations in thermal expansion/contraction, aging, wear in the valve seat, valve , head, shims and piston wear and well as to cope with variation in clamping.
  • a fuel injector including an actuator operated valve, said valve being located within a valve body, a method comprising determining the condition where, or the point when, there is or is not electrical continuity between two injector components adapted to move relative to one another during operation.
  • the two said components may be one end of an actuator and a control valve or valve needle.
  • the method may determine when the gap between the two said components is reduced to zero.
  • the valve may be actuated by a piezoelectric actuator.
  • the method may include determining when there is electrical continuity between the end of the actuator and the valve/needle or proximal portion of the valve/needle.
  • the method may comprise the step of determining the point of contact between the end of the actuator and the valve/needle.
  • valve/needle may be in electrical contact with said valve body, and said valve body is at ground potential.
  • the method may include providing an electrical path or lead at having a contact at the extremity of the actuator, such that when said gap is reduced to zero, said contact makes electrical contact with the valve/needle.
  • the electrical path/lead may comprise wiring connected or connectable to a terminal of the piezo-electric stack/actuator or an engine ECU.
  • the said electrical path/wire may be connected to the negative terminal of the piezoelectric stack/actuator
  • the method may include electrical insulating said electrical path/ wire from the valve body or ground potential.
  • a method of estimating a gap between the end of the piezo electric stack/actuator and the valve/needle comprising varying the voltage applied to a piezoelectric stack and using any of the above methods to determine the point at which the gap is zero.
  • the method may include determining the point at which the valve/needle moves away from contact with the valve body by determining electrical continuity therebetween.
  • the fuel injector may include an actuator adapted to contact a valve/needle member, said valve/needle member or actuator being biased in a closed state by a deformable member located on a collar of said valve body, insulating said deformable member from said valve/valve collar body
  • the method may determine the operational phase/state of a fuel injector.
  • a method of compensating for variation in injector characteristics including utilising the above methods and controlling the operation of said injector as a consequence.
  • a fuel injector including an actuator operated control valve/valve needle, said valve/needle being located within a valve body, comprising means to determine the condition where, or the point when, there is or is not electrical continuity between two injector components adapted to move relative to one another during operation.
  • the valve may be actuated by a piezoelectric actuator.
  • the fuel injector may include means to determine when there is electrical continuity between the end of the actuator and the valve/needle or proximal portion of the valve/needle .
  • the fuel injector may include means to determine the point of contact between the end of the actuator and the valve/needle.
  • valve At said point of contact the valve is in electrical contact with said valve body, and said valve body may be at ground potential.
  • the fuel injector may have an electrical path or lead at having a contact at the extremity of the actuator, such that when said gap is reduced to zero, said contact makes electrical contact with the valve.
  • Said electrical path/lead may comprises wiring connected or connectable to a terminal of the piezo-electric stack/actuator or an engine ECU.
  • the electrical path/lead may be connected to said terminal via a resistor.
  • Said electrical path/wire is connected to the negative terminal of the piezoelectric stack/actuator
  • the fuel injector may include electrical insulating of said electrical path/ wire from the valve body or ground potential.
  • the fuel injector may include means to determine the point at which the valve/needle moves away from contact with the valve body by determining electrical continuity therebetween.
  • the fuel injector may includes an actuator adapted to contact a valve/needle member, said valve/needle member or actuator being biased in a closed state by a deformable member located on a collar of said valve body, insulating said deformable member from said valve/valve collar body
  • Figures 1 a, b , c and d show sectional views of a fuel injector 1 which includes a piezoelectric stack 2 located within a housing 4 along a generally common central axis.
  • the stack operates to move in slidable fashion, an injection needle 3 so as to move the tip of the needle to/away from a valve seat so as to dispense fuel into a combustion space.
  • Figure b shows in enlarged view the end portion of the stack which includes stack components 2a,2b which in operation contact with the top end of the needle so as to actuate the needle on extension/retraction of the stack.
  • Figure c shows a further expanded view showing the location of the gap between the end of the needle and the end component 2b of the stack arrangement, and figure 1d shows the situation with no gap.
  • Figure 2a also shows a known design of fuel injector.
  • Figure 2b shows in more detail the spring installation portion.
  • Figure 2c shows the equivalent portion of the fuel injector to figures 1a and c.
  • Such a piezo-injector is intended to be designed without a lash adjuster between the actuator and the valve.
  • a gap is required between the actuator (stack) and the valve to ensure that the valve remains shut at different thermal conditions.
  • the size of the gap can vary with temperature, piezo aging, valve/actuator wear, clamping force etc.
  • one option is to operate the injector control valve without any lash compensation or adjustment device, in direct contact between actuator and valve. In this configuration, due to thermal and ageing effects, there is a small gap between the actuator and the valve, when the actuator is not activated or energized. This gap is varying strongly, in function of the temperature, and other effects, like wear, piezoelectric ageing etc.
  • Figure 3 shows the sequence of event on actuation of the piezoelectric stack.
  • the gap is reduced as the end of the stack/stack components contact the top face of the needle.
  • the top portion of the needle may be connected to other components, the most distal (uppermost) contacting the stack components in operation.
  • the needle is pushed downwardly from the downward force from the stack.
  • this gap influences strongly the performance of the injector, as it introduces some variation in the valve movement, for a given actuator movement. It is important, for good consistency in the injector performance, to control and compensate this gap.
  • many injectors are intended to have closed loop control. It is important that the actuator and valve must be in contact for measurement of force change on the valve to enable closed loop control. Therefore, it is necessary to have a means of measuring or estimating the magnitude of this gap, or the point at which the gap is zero, during operation on the injectors , and allow a vehicle ECU to compensate this gap via a correction on the injector drive signal.
  • Some techniques include using hydraulic lash adjustors/amplifiers) are using strategies based on detection of stress/force change on the actuator when there is contact between the actuator and the valve, measured by detection of a change in the actuator capacitance. Other methods are based on detection of pressure decay in the rail, when the actuator manages to slightly open/leak the control valve, indicating that the gap is closed.
  • a method for compensating for the gap by being able to detect when the actuator contacts the top of the valve using electrical continuity between the two components.
  • the vehicle ECU is adapted to detect the point at which there is electrical continuity between the actuator assembly and the valve (vehicle ground), hence when the actuator is in contact with the valve. This provides an effect simple and highly precise way of determining if there is a gap present or at which point the gap is reduced to zero, simply by determining is there is electrically continuity between the two elements.
  • Injector valves, and needles are generally electrically connected to the vehicle earth through the injector body due to the fact it is steel and in contact with the steel valve body.
  • the piezo actuator/stack assembly is electrically insulated from the other injector components, by providing an insulation sleeve 5 as shown in figure 4.
  • Figure 4 a and b shows portions of a fuel injector showing the piezo stack/actuator according to one example. Insulation is provided to insulate the piezo stack/actuator from the rest of the injector.
  • the negative electrode 6(terminal) of the injector can be used as the lead to determine electrical continuity and there is provided a wire 7 from the negative terminal which runs to the distal end (tip) of the peizo actuator, and insulated from the rest of the valve/injector body.
  • appropriate signal can be sent to the negative electrode and it can be determined if there is contact with the zero earth potential of the needle when the gap therebetween is zero such that there is electrical continuity.
  • Figure 5 shows an alternative embodiment where the actuator assembly may be provided with an additional (3 rd ) wire 8 connected from the ECU or the negative electrode of the piezo-stack.
  • This 3 rd wire may be connected/connectable to an engine ECU. The ECU by appropriate voltage regulation to this third wire can then ascertain any electrical continuity.
  • the voltage on the piezo-stack can be ramped up or down, i.e. a varying voltage applied to the stack to determine the point at which the actuator loses/makes contact with the valve and hence determine the size of the gap. Compensation for the size of the gap could then be applied to the injector drive signal.
  • aspects of the invention may be applicable to servo injector where the valve needle is not directly operated by the actuator.
  • the actuator operates a control valve which moves the valve needle using a hydraulic circuit.
  • the gap may be between the actuator and control valve.
  • Figure 6a shows an example of the invention showing a schematic representation of the actuator portion 10 which includes a coating.
  • Figure 6b shows a schematic representation of a further example showing the actuator portion 10 with an insulation layer 12.
  • an insulating washer may be provided at the top portion and/or bottom.
  • Figure 6c shows an alternative example showing the actuator portion showing an additional sensor wire 15. The figure also shows the gap between the actuator and the valve as effectively represented as a switch.
  • Figure 6d shows another alternative without the extra sensor wire but which uses the existing Piezo actuator terminals with actuator portion 10 with resistor 14.
  • Figure 7a shows a standard drive circuit for a series of piezo-actuated injectors.
  • a driver circuit 22 supplies electrical voltage to the Piezo actuators 23, arranged in parallel.
  • a particular Piezo actuator is switched vie injector select switch 24.
  • a discharge resistor 25 is located in parallel with each Piezo actuator.
  • the low side injector select is the standard way to drive the injectors.
  • Figure 7b shows a modified shows a representation of the drive circuit which can be used according to one example where an extra wire is not used but the existing actuator/piezo terminals are used.
  • the injector select switches have been located on the high side circuit. The switches represent contact between the actuator and valve.
  • Figure 7c illustrate a further alternative drive circuit according to one example and is also for embodiments which do not use the extra wire.
  • the circuit is similar to the figure 7a circuit but' the includes an extra resistor Radjust for each Piezo actuator. This may again require high side injector select switch (normally on low side) or separate injector drivers to isolate each switch to only discharge its own actuator.
  • the typical output for the electrical continuity during an injection for the figure 6 embodiment can be seen in figure 9 along with the piezo voltage/ injector voltage (although in reality the injection may occur with no gap as that could be compensated for away from the injection as previously mentioned).
  • the time axis includes 5 phases, i) gap, ii) force to open valve, iii) valve opening, (these relate to valve opening) and iv) force decay and v) gap (the latter two relate to valve closing). Electrical continuity is shown for these phases; when the valve is forced open and on forced decay there is electrical continuity In one aspect, compensation could therefore be made for any evolution of the force required to open the valve and also any evolution of the force closing the valve.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Analytical Chemistry (AREA)
  • Fuel-Injection Apparatus (AREA)
EP15159321.7A 2014-04-09 2015-03-17 Verfahren zur steuerung und diagnose bezüglich des betriebs eines kraftstoffeinspritzers Withdrawn EP2930346A1 (de)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GBGB1406356.4A GB201406356D0 (en) 2014-04-09 2014-04-09 Method for the control and diagnosis regarding the operation a fuel injector

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EP2930346A1 true EP2930346A1 (de) 2015-10-14

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19929589A1 (de) * 1998-07-02 2000-01-13 Avl List Gmbh Einspritzeinrichtung für eine Brennkraftmaschine
DE19905340A1 (de) * 1999-02-09 2000-08-10 Siemens Ag Verfahren und Anordnung zur Voreinstellung und dynamischen Nachführung piezoelektrischer Aktoren
DE10129375A1 (de) * 2001-06-20 2003-01-02 Mtu Friedrichshafen Gmbh Injektor mit Piezo-Aktuator
WO2003052260A1 (de) * 2001-12-18 2003-06-26 Robert Bosch Gmbh Brennstoffeinspritzventil

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19929589A1 (de) * 1998-07-02 2000-01-13 Avl List Gmbh Einspritzeinrichtung für eine Brennkraftmaschine
DE19905340A1 (de) * 1999-02-09 2000-08-10 Siemens Ag Verfahren und Anordnung zur Voreinstellung und dynamischen Nachführung piezoelektrischer Aktoren
DE10129375A1 (de) * 2001-06-20 2003-01-02 Mtu Friedrichshafen Gmbh Injektor mit Piezo-Aktuator
WO2003052260A1 (de) * 2001-12-18 2003-06-26 Robert Bosch Gmbh Brennstoffeinspritzventil

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GB201406356D0 (en) 2014-05-21

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