Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/24—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means
  • F02D41/2406—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means using essentially read only memories
  • F02D41/2425—Particular ways of programming the data
  • F02D41/2429—Methods of calibrating or learning
  • F02D41/2451—Methods of calibrating or learning characterised by what is learned or calibrated
  • F02D41/2464—Characteristics of actuators
  • F02D41/2467—Characteristics of actuators for injectors
• • 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
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/24—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means
  • F02D41/2406—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means using essentially read only memories
  • F02D41/2425—Particular ways of programming the data
  • F02D41/2429—Methods of calibrating or learning
  • F02D41/2438—Active learning methods
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/30—Controlling fuel injection
  • F02D41/38—Controlling fuel injection of the high pressure type
  • F02D41/40—Controlling fuel injection of the high pressure type with means for controlling injection timing or duration
• • 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
• • 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
  • F02D2041/2003—Output circuits, e.g. for controlling currents in command coils using means for creating a boost voltage, i.e. generation or use of a voltage higher than the battery voltage, e.g. to speed up injector opening
• • 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
  • F02D2200/00—Input parameters for engine control
  • F02D2200/02—Input parameters for engine control the parameters being related to the engine
  • F02D2200/06—Fuel or fuel supply system parameters
  • F02D2200/0618—Actual fuel injection timing or delay, e.g. determined from fuel pressure drop
• • 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
  • F02D2200/06—Fuel or fuel supply system parameters
  • F02D2200/063—Lift of the valve needle
• • 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
  • F02M47/00—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure
  • F02M47/02—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure of accumulator-injector type, i.e. having fuel pressure of accumulator tending to open, and fuel pressure in other chamber tending to close, injection valves and having means for periodically releasing that closing pressure

Definitions

• the invention relates to method to determine the needle opening delay (OD) of a fuel injector.
• the needle opening delay can be considered the time lag between when an activation pulse is sent to fuel injector and the time that the needle starts to moves away from its seat to dispense fuel.
• Modern fuel injectors typically use electrical actuators such as piezo or solenoid operated actuators which are used to activate a valve, the valve opening and closing in order to dispense fuel to a combustion chamber via movement of a needle away from a seat.
• an activation pulse of certain duration is sent to the fuel injector to activate the fuel injector via activating the actuator.
• Modern fuel injectors are hydraulically operated in that rather than the actuator actuating the needle directly, the actuator used to operate a valve (system) so as to control pressure in the fuel injector, so as to indirectly operate the fuel injector by movement of a needle to or from a needle seat, using such pressures, so as to selectively dispense fuel.
• actuator operated valve opening and closing and needle opening and closing.
• the opening delay There is typically a time delay between the leading edge of the pulse, i.e. start of activation and the needle valve opening; this is referred to as the opening delay.
• Some designs of fuel injector typically also provide a switch signal, provided often by an extra wire, where a signal on the wire provides means to detect when two moving parts in the injector system are in or out of contact with each other. This may be for example detecting when the valve needle and nozzle/needle seat come into contact or are out of contact with each other, or when the needle after opening (moving away from the valve seat) comes to its end (fully open) stop.
• a switch signal provided often by an extra wire, where a signal on the wire provides means to detect when two moving parts in the injector system are in or out of contact with each other. This may be for example detecting when the valve needle and nozzle/needle seat come into contact or are out of contact with each other, or when the needle after opening (moving away from the valve seat) comes to its end (fully open) stop.
• Many prior art systems use this switch signal to determine the opening time of the injector needle valve or other components. However the use of switch signals which determine the opening time of the needle are sometime unreliable.
• a method of determining the opening delay of a solenoid actuated fuel injector said fuel injector including a solenoid actuated valve adapted to actuate a needle valve, said needle valve comprising a needle adapted to move from an closed state to an open state and to a closed state during an operational cycle of said injector, comprising the following steps: a) providing series of test injection cycles with varying solenoid actuator drive pulse durations information (Ton);
• VCT solenoid actuated valve
• NCT needle closing time
• the opening delay may be determined as the determined sum at the intersect.
• NCD NCT - VCT
• NFST and or NCT may be determined from the injector switch signal.
• Said closing time of the solenoid actuated valve may be determined by analyzing the voltage across the solenoid of the solenoid actuated valve and identifying a time of glitch.
• the method may include storing a reference plot of NCD value against the sum Ton, VCD and CCFT for a reference injector, and providing a refined value of opening delay (Refined OD injx) from the value found from step h) and the data from the reference plot.
• the refined value of opening delay (refined OD injx) may be determined from the following equation
• ODref map is a stored or determined value for a reference injector, representing the sum (Ton + VCD + CCFT) at a zero value of the NCD for the reference injector; pseudo ODref map is the value of the sum (Ton + VCD + CCFT) at the CCFT threshold value of the NCD with respect to the reference plot.
• FIG. 1 shows a schematic diagram of a solenoid operated fuel injector system
• Figure 2a, 2b, 2c show three operational states of the fuel injector with reference to the needle position and the current which flows throught the additional wire to ground;
• FIG. 3 shows the corresponding timeline of the activation pulse sent to the solenoid (top plot), the middle plot shows corresponding timeline of the injection period which is the time from needle opening to closing , and the bottom plot shows the corresponding states of the voltage on the switch signal with the various opening and closing and intermediate states corresponding to that of figure 2;
• Figure 4 shows corresponding timelines of activation pulse, valve lift, needle command (position) and needle lift respectively;
• Figure 5 shows the values of the sum of (Ton + VCD + CCFT) plotted against CCFT/NCD;
• Figure 8 illustrates an advanced method of refining the estimated value of opening delay.
• Figure 1 shows a schematic diagram of a solenoid operated fuel injector system which includes a fuel injector 1 (shown in schematic cross section) and includes additional wiring 2 which allows detections of the operational state of the injector.
• the figure shows the ECU portion 3, the harness portion 4 and the injector portion 5.
• the injector portion shows the solenoid 6 of the actuator.
• the additional wiring 5 provides two current paths 7 and 8 to ground as shown depending on the position of the needle.
• the operational state of the injector can be monitored by measuring the voltage on line 9, which allows detection of the state of the needle contacts when it is fully closed fully open and partially open.
• Figure 2a-c shows three operational states of the fuel injector with reference to the needle position and the current which flows throught the additional wire to ground.
• Figure 2a shows the needle in the closed state A where there is flow of current to ground when the needle contacts the needle seat (bottom contact) - the voltage on line 9 is OV.
• Figure 2b shows where the needle is partially open in state B and there is no contact with ground through the additional wire and hence no current flow; the voltage on line 9 is high.
• Figure 2c shows the needle when it is in the open position C and there is flow throught the additional wire to ground via the top contact of (the needle is fully open) via pathway 7.
• the voltage on line 9 is OV.
• Figure 3 shows the corresponding timeline of the activation pulse 10 sent to the solenoid (top plot), the middle plot shows corresponding timeline of the injection period 11 which is the time from needle opening to closing , and the bottom plot shows the corresponding states of the voltage on the switch signal line 9 with the various opening and closing and intermediate states corresponding to that of figure 2.
• State A is where the needle is closed, the needle subsequently starts to lift at PI and the signal on the switch line 9 goes high as there is no current path through the additional wire when the needle is partially open/closed in the transition state B.
• State C is where the needle reaches fully open point P2 and the signal on the switch line 9 goes to zero as current can flow through the additional wire due to the top contact.
• the Needle Falling Start Time at point P3 can be determined . So the figure shows the various states when the needle is in full lift, the top switch is activated and the switch signal goes to 0V. When the needle is travelling back to the seat the short circuit in the top switch disappears and the switch signal is going from 0V to 5V.
• the needle closing time (NCT) is point P4.
• the NFD Needle falling duration can also be computed from the switch signal also and is determined as the period D, between points P3 and P4 in figure 3 .
• Figure 4 shows corresponding timelines of activation pulse 110, valve lift 111, needle command (position) 112 and needle lift 113 respectively.
• the following annotations are used in the figures and description:
• VCT Valve closing time
• VCD valve closing delay
• NOL needle opening length/duration
• the top plot 110 shows the activation pulse which has a length (duration) of Ton. Underneath is shown the valve lift 111 and shows the valve starts to move/open at point PI 1 and closes at point P12.
• the assumed VCD is the time between the end of the activation pulse and the time of the VCT.
• the plot 12 below this shows needle effective command and the bottom plot 113 shows the actual movement of the needle and shows a small timespan where the needle lifts to allow injection of fuel and this show a small bell shaped pulse over a timespan of NOL.
• the needle falling duration is as shown and is generally over the second half of the NOL.
• NFD 0
• the needle opening delay is determined from the following input parameters: a) The (actuator) valve closing time (VCT). This parameter can be determined from analysis of the current/voltage across the solenoid actuator. Typically when the solenoid valve closes, there is a detectable glitch in the voltage plot which can be preferably determined by looking at the values of dV/dt and or the second derivative. The glitch is determined by observing a point of inflection in the current plot, and such techniques are well known in the art.
• the needle closing time (NCT) information can be provided from a switch signal as described above, the time at point P4 at the end of the period D.. This provide the parameter NCT.
• the NFD Needle falling duration.
• NCD NCT - VCT.
• Figure 5 shows such a plot.
• the Opening Delay is determined by finding the intersection between this curve and the NCD value that corresponds; i.e. is equal to the CCFT threshold value; the later which will be explained hereinafter. So using the above input data, an NCD curve function is plotted by providing a plurality of injector operations (cycles) with different activation pulse lengths (Ton). This may be performed using a "sweep" where the fuel injector is activated with e.g.
• Ton is the activation pulse duration.
• VCD valve closing delay
• NFST can be determined from the switch signal as described above. So to recap the value of (Ton + VCD + CCFT) is plotted against NCD and is shown in figure 5 as mentioned .
• the threshold value of CCFT is determined; this can be regarded as the maximum CCFT. If CCFT is plotted against pulse length (Ton), the value will increase (during the ballistic range) ) and reach a plateau. This is the CCFT threshold and so this can be determined by looking at the plateau value thereof with increasing pulse length. So to recap CCFT against pulse length (Ton) will go up and reach a plateau and the value at the plateau will be used as the threshold value.
• the CCFT threshold value can be regarded as a NCD threshold value as will be explained below.
• a line is drawn horizontally on the y-axis (the NCD axis at the CCFT threshold value) i.e. the threshold value of CCFT on the NCD axis and the at this intersect point with the plot on the x-axis is determined as the opening delay OD.
• Figure 6 and 7 shows further plots comparing the values of various parameters for ballistic and non-ballistic (full lift) operations of the fuel injector
• the reference numerals denote the activation pulse (in the case of full lift this is sufficient in length to operate out of ballistic mode) denotes the valve opening state signal denotes the needle signal and shows the needle lift state.
• the full lift CCFT is used.
• the NCD Threshold will be a value dependent on the full lift CCFT.
• NCD will be plotted function of (Ton + VCD + full lift CCFT).
• the full lift CCFT can be calculated as explained above as well as the valve closing time determined e.g. from a glitch in the voltage plot of the solenoid.
• CCFT NFST - VCT, see fig.3 Refinement
• Ton+VCD+CCFT for an ideal i.e. reference injector.
• This stored (ref injector OD) reference map can be provided from data recorded on hydraulic rig /from an injection rate measurement device, and can be stored on an ECU.
• Figure 8 shows a graph plot of (Ton + VCD + CCFT) 20 plotted against NCD for an
• the plot for the test injector Injx 20 should be generally parallel to the curve for the reference injector of InjRef. 21. It is again to be noted that data regarding the test injector is not available at low levels. Thus the intersection of the test plot with the X-axis never appears because even for very small quantity, NCD is not null (it is very small but not null), it corresponds to the CCFT value for small quantity. This delay depends on the hydraulic behaviour of the injector. However this data is usually available.
• the following method steps are then taken: i) From the reference injector plot, i.e., on the stored map/chart, the 0 (y-axis) crossing is used to get a value of the parameter OD re f map zero (where NCD is zero) . As this is fixed, this may be stored on a table. ii) Also the current NCD threshold (current threshold CCFT) which is variable and as explained above is used to find initially estimated value of OD for the test injector (Pseudo) OD mj x for the test injector is also used to determine the equivalent Pseudo OD re f for the reference injector designated Pseudo OD re f map. iii) These two parameters are used along with the value of the NCD threshold crossing for the test injector which as previously described is Pseudo OD mjx, to get real OD m j x (using the formula) below:
• Estimated refined OD injx OD re f map + ((pseudo )_ODmj x - pseudo_OD re f map) So in summary the real OD of the reference injector will be stored as a calibration in the ECU, it will be called ODR e f map.
• the pseudo OD of the reference injector will also be stored as a calibration dependent on the level of NCD for test injector, it will be called Pseudo ODRef map.
• the difference between (pseudo)ODmjx and pseudo ODref map will be added to the ODR e f map to have the estimated OD of the injx.
• the present invention is an indirect way to determine the OD of a fuel injector.
• the old system was a direct measurement of the needle opening thanks to the switch signal. But this system was sometimes not reliable.

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

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• 2017
  • 2017-10-18 GB GB1717099.4A patent/GB2567809B/en active Active
• 2018
  • 2018-10-09 WO PCT/EP2018/077524 patent/WO2019076691A1/en unknown
  • 2018-10-09 EP EP18785925.1A patent/EP3698035A1/de active Pending
  • 2018-10-09 CN CN201880067871.1A patent/CN111247323B/zh active Active

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