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EP2514956A1 - Verfahren zur Steuerung eines elektromagnetischen Betätigers - Google Patents

Verfahren zur Steuerung eines elektromagnetischen Betätigers Download PDF

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Publication number
EP2514956A1
EP2514956A1 EP11163590A EP11163590A EP2514956A1 EP 2514956 A1 EP2514956 A1 EP 2514956A1 EP 11163590 A EP11163590 A EP 11163590A EP 11163590 A EP11163590 A EP 11163590A EP 2514956 A1 EP2514956 A1 EP 2514956A1
Authority
EP
European Patent Office
Prior art keywords
time
switch
armature
actuating
fuel
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Withdrawn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
EP11163590A
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English (en)
French (fr)
Inventor
Abdelhamid Bouaita
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.)
BorgWarner Luxembourg Automotive Systems SA
Original Assignee
Delphi Automotive Systems Luxembourg SA
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 Automotive Systems Luxembourg SA filed Critical Delphi Automotive Systems Luxembourg SA
Priority to EP11163590A priority Critical patent/EP2514956A1/de
Publication of EP2514956A1 publication Critical patent/EP2514956A1/de
Withdrawn legal-status Critical Current

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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
    • F02D41/20—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
    • F02D41/20—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

Definitions

  • the present invention generally relates to electromagnetic actuators and more specifically to a method of controlling an electromagnetic actuator taking into account switching delays.
  • a particular field of application is that of internal combustion engines using electromagnetically actuated fuel injectors.
  • One requirement to reduce emissions from a spark ignited internal combustion engine is an accurate control of the combustion air/fuel ratio. This is usually done by metering a precisely controlled amount of fuel based on a measured or inferred air charge mass inducted into the engine; many control schemes are known in the art to control the air/fuel ratio. It is e.g. customary to install an oxygen sensor in the engine exhaust line and to use the sensor output as a feedback signal for closed loop fuel control.
  • WO 03/023211 describes a method of determining response times of electromagnetic devices. The determination of injector response times at switch-on and switch-off is based on current detection; the determination of the response time at closing is also described based on voltage detection.
  • Deviation and variability between injectors are usually due to the dispersion of the injectors characteristics linked to the production process spread and/or to the time-drift variations of the same characteristics due to ageing. Thus, fuel injector flow variations need to be corrected.
  • the problem of fuel variability is particularly critical for low fuel injections, i.e. when injecting small or minute fuel amounts.
  • the knowledge of the opening and closing delays is particularly useful to conduct an optimised injector control.
  • the object of the present invention is to provide a method of controlling an electromagnetic actuator with an alternative determination of switch-on time.
  • the present invention relies in part on previous findings made by the present Applicant that the accuracy of low (or minute) fuel injections can indeed be improved by detecting more precisely than before response timings of the pintle lift event of the injector and that injector response time data such as closing time data and opening time data can serve to correct the injection pulse width that is used to inject a desired quantity of fuel in the combustion chamber.
  • a method of controlling an electromagnetic actuator having an excitation coil and a movable armature wherein an actuating event is triggered by applying a control signal to move said armature from a rest position thereof towards an actuating position, and in particular actuating events where the armature motion is in the ballistic domain.
  • the method comprises the steps of:
  • the control signal for a next actuation event of the electromagnetic actuator can thus be corrected, respectively elaborated, taking into account the switch-on time.
  • the so-learned timing information allows elaborating learned correction values that can be advantageously used for the injection control and namely for low injection pulses.
  • learned correction values may be elaborated in respect of the closing times (t off ) on the one hand
  • learned correction values may be elaborated in respect of the opening times (t on ) on the other hand.
  • a corrected control signal is elaborated that takes into account both the opening and closing delays.
  • the opening time of a given injector is considered to be relatively constant and one value of opening time may be stored per injector. However, this value may vary with ageing, or some injectors may have a different behaviour. Therefore, the determination of opening time may be periodically determined.
  • the present method has been particularly developed for an optimised control of modern fuel injectors, where the opening and closing delays may substantially affect the injected fuel quantity for "minute or "low” fuel injections, if not properly taken into account.
  • Such "minute or “low” fuel injections are injection pulses of low fuel quantities, which are achieved through brief injector pintle openings and where the pintle is mainly in a transitory position between the fully open position and the closed position.
  • Performing such low fuel injections involves operating the injector in the "ballistic" domain, where closing and opening time correction has appeared to be particularly advantageous.
  • injections of fuel masses of up to 5 or 6 mg involve operation in the ballistic domain.
  • the present method is of particular interest for the control of fuel injectors with electromagnetic actuators of the so-called decoupled type, i.e. where the armature is not rigidly linked to the pintle, and thus tend to have a ballistic behaviour.
  • the timing t max is determined as the timing at which a curve representative of the logarithm of the voltage at the excitation coil during a predetermined observation window before the switch-off time intersects a straight line representative of the logarithm of the excitation coil voltage after the switch-off time.
  • the natural (base e) logarithm may be used, or other base.
  • the observation window may start after the fall of the control signal for the respective actuating event, preferably when it has been determined that the coil current has become null.
  • the invention concerns a method of controlling fuel injection in an internal combustion engine according to claim 9.
  • the invention concerns an internal combustion engine comprising at least one cylinder with at least one fuel injector as defined in claim 11, respectively 12.
  • the fuel injector comprises a pintle actuated by an electromagnetic actuator having an excitation coil and a movable armature.
  • An engine management system (EMS) is adapted to trigger an actuating event (injection event) of the fuel injector by applying a control signal to the latter so as to move the armature, respectively the pintle, from a rest position thereof towards an actuating position and cause a corresponding fuel injection.
  • the control signal is generated to on the basis of a fuel command pulse width, conventionally mapped in function of the fuel amount to be injected.
  • the engine management system is further configured to:
  • the present inventors have developed the present method when working on opening and closing delays of fuel injectors operating in the ballistic domain.
  • the present invention will thus now be explained in detail with regard to an actuating event of a fuel injector.
  • the invention can be used to optimize the operation of any type of electromagnetic actuator having an excitation coil (also called solenoid), i.e. having an inductance, and a movable armature operating in the ballistic domain.
  • the switch off time t off may be called closing time/delay and the switch-on time t on may be referred to as opening time/delay.
  • the opening and closing times are both determined from voltage feedback from the injector, which results in a coherent data processing as the timings can then simply be determined from a single source of information.
  • the switch-on time is determined on the assumption that the switch-on time is separated from the switch-off time by an actuating duration, which represents approximately twice the time separating the extremum stroke time from the switch-off time.
  • this method can be implemented as follows:
  • the injector closing time is known in the art.
  • the injector closing time noted t off and occuring at time t5 is preferably deduced from the coil voltage.
  • the determination of the injector pintle closing response is preferably carried out based on the voltage feedback from the injector.
  • the voltage may be measured across the injector coil terminals.
  • the injector armature hits the seat and stops, there is a visible and measurable change in the slope of the injector coil voltage (indicated by arrow 2 in Fig.1 ).
  • the perturbation in the voltage can be traced back to a change in the velocity term of the flux linkage I.dL / dx.dx / dt, where dx / dt is the velocity of the armature, which is greatly reduced when the pintle closes.
  • the measurements preferably take place after the command pulse has ended and the currents have gone to zero, leaving only eddy currents and trapped flux in the magnetic circuit. These conditions enable an easier sensing of the closing voltage signature.
  • fuel mass is primarily determined by the pulse width and the closing delay of the injector pintle, after the pulse width ends.
  • Closing Time t off is then an excellent indicator of fuel flow: part with higher closing time will deliver more fuel than one with shorter closing time.
  • the determination of the maximum stroke is also prerably done on the basis of coil voltage feedback. And the present approach is actually based on the fact that the armature position affects the coil inductance value.
  • the inductance L depends on 2 parameters: the current i and the gap between armature (i.e. moving body) and coil, this gap being indicated by x in the following equation.
  • the determination of the maximum stroke thus involves monitoring the coil inductance to extract motion characteristics.
  • line 10 indicates the pintle stroke (pintle lift), line 12 the actuation logic (command signal or pulse width), line 14 the current in the injector coil and line 16 the voltage at the injector coil (lower graph).
  • the present example is that of an actuating event in the ballistic domain.
  • the actuation logic generates a step between times t1 and t3 in order to charge the coil with the aim of opening the injector.
  • the pintle starts moving at time t2 and closes at time t5.
  • the goal is to close the actuator and the control logic applies directly after time t3 a negative voltage - V 0 to the coil in order to collapse the current in the coil and cancel the magnetic field.
  • In(V) is a straight line having a constant slope ⁇ .
  • ln(V) vs. time.
  • ln(V) describes a wave shape between time t2 and t5, where the falling front approximately coincides with timing M, which is the maximum stroke of the pintle.
  • timing M which is the maximum stroke of the pintle.
  • the timing of maximum stroke is determined from the voltage feedback and, as shown in Fig.2 , the timing of the maximum stroke is approximated as the intersection of the straight line corresponding to ln(V) after time t5 (when the pintle has reached its closed position) with the curve ln(V) .
  • the present inventors have indeed observed that this intersection point, indicated by arrow 4 in Fig.2 , is strongly correlated with the point of maximum stroke (at M).
  • an injector opening later will show the same pattern as in Fig.2 , however shifted to the right, and the same applies to the intersection point.
  • this may be carried out by sampling coil voltage values over an observation window extending from before the max stroke point M to t5, the closing time.
  • the start of the observation window may be determined from calibration and in view of the requested actuating motions.
  • the observation window-indicated 20 in Fig.2 - may typically start when the current has become null (at t4).
  • the ECU may for example be configured to perform mathematical regression in order to determine an equation fitting the acquired voltage points after t5 as well as an equation fitting the acquired voltage points in the observation window.
  • pintle stroke vs. time - as shown in Fig.1 . It shall be appreciated that in the present method it is thus considered that about the same time is required for the pintle to move from the Maximum stroke to its closed position, than from the opening time to the maximum stroke - these motions occurring during the actuating duration.
  • a fuel command pulse width is determined for each injection event in an engine cycle. Pulse widths are mapped in function of fuel amounts, the latter depending on the requested torque and being corrected using known tools such as e.g. the so-called block learning memory (BLM) and Individual Cylinder Fuel Control (see e.g. US 6,382,198 ).
  • BBM block learning memory
  • Individual Cylinder Fuel Control see e.g. US 6,382,198 .
  • a pulse width is determined (as well as a corresponding control signal) to command a corresponding opening duration in order to deliver a predetermined fuel amount.
  • Injector closing time and opening time information can thus be advantageously employed to improve the injection of fuel quantities, namely of low fuel quantities.
  • a learned correction value may then be determined that is then applied to the pulse width determined by conventional methods.
  • the engine management system may comprise a table of learned closing times that is used for injection control, the table of learned closing times giving normalized, average closing time values for each injector (or cylinder) and a set of pulse widths corresponding to minute fuel injections.
  • the table of learned closing times giving normalized, average closing time values for each injector (or cylinder) and a set of pulse widths corresponding to minute fuel injections.
  • the engine may then be controlled with a calibrated map of closing times and opening times, and a pulse width correction may be performed based on a difference between the calibrated and learned closing times as well as calibrated and learned opening times.

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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)
EP11163590A 2011-04-22 2011-04-22 Verfahren zur Steuerung eines elektromagnetischen Betätigers Withdrawn EP2514956A1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP11163590A EP2514956A1 (de) 2011-04-22 2011-04-22 Verfahren zur Steuerung eines elektromagnetischen Betätigers

Applications Claiming Priority (1)

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EP11163590A EP2514956A1 (de) 2011-04-22 2011-04-22 Verfahren zur Steuerung eines elektromagnetischen Betätigers

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EP2514956A1 true EP2514956A1 (de) 2012-10-24

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012152835A3 (de) * 2011-05-09 2013-02-28 Continental Automotive Gmbh Verfahren zum erkennen eines schliesszeitpunktes eines einen spulenantrieb aufweisenden ventils und ventil
WO2014121982A1 (de) * 2013-02-07 2014-08-14 Robert Bosch Gmbh Verfahren zum betrieb eines kraftstoffeinspritzsystems eines verbrennungsmotors
DE102017215017A1 (de) 2017-08-28 2019-02-28 Hitachi Automotive Systems, Ltd. Verfahren und Einrichtung zum Betreiben eines elektromagnetisch betätigten Ventils eines Kraftstoffeinspritzers
US10401398B2 (en) 2017-03-03 2019-09-03 Woodward, Inc. Fingerprinting of fluid injection devices
WO2022090397A1 (de) * 2020-10-30 2022-05-05 Volkswagen Aktiengesellschaft Verfahren zum ermitteln eines schliesszeitpunkts eines injektors mit einem magnetventil, computerprogramm, steuergerät, verbrennungskraftmaschine und kraftfahrzeug

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4011217A1 (de) * 1990-04-06 1991-10-10 Lucas Ind Plc Verfahren zum ansteuern eines magnetventils einer schlupf-regelanlage
US6382198B1 (en) 2000-02-04 2002-05-07 Delphi Technologies, Inc. Individual cylinder air/fuel ratio control based on a single exhaust gas sensor
WO2003023211A1 (de) 2001-08-16 2003-03-20 Robert Bosch Gmbh Verfahren und vorrichtung zur steuerung eines elektromagnetischen verbrauchers
DE102008040222A1 (de) * 2008-07-07 2010-01-14 Robert Bosch Gmbh Verfahren zum Betreiben eines Injektors und Steuergerät hierfür
DE102009027290A1 (de) * 2008-09-16 2010-04-15 Robert Bosch Gmbh Verfahren und Steuergerät zum Betreiben eines Ventils
WO2011039043A1 (de) * 2009-10-02 2011-04-07 Robert Bosch Gmbh Verfahren und steuergerät zum betreiben eines ventils

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4011217A1 (de) * 1990-04-06 1991-10-10 Lucas Ind Plc Verfahren zum ansteuern eines magnetventils einer schlupf-regelanlage
US6382198B1 (en) 2000-02-04 2002-05-07 Delphi Technologies, Inc. Individual cylinder air/fuel ratio control based on a single exhaust gas sensor
WO2003023211A1 (de) 2001-08-16 2003-03-20 Robert Bosch Gmbh Verfahren und vorrichtung zur steuerung eines elektromagnetischen verbrauchers
DE102008040222A1 (de) * 2008-07-07 2010-01-14 Robert Bosch Gmbh Verfahren zum Betreiben eines Injektors und Steuergerät hierfür
DE102009027290A1 (de) * 2008-09-16 2010-04-15 Robert Bosch Gmbh Verfahren und Steuergerät zum Betreiben eines Ventils
WO2011039043A1 (de) * 2009-10-02 2011-04-07 Robert Bosch Gmbh Verfahren und steuergerät zum betreiben eines ventils

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012152835A3 (de) * 2011-05-09 2013-02-28 Continental Automotive Gmbh Verfahren zum erkennen eines schliesszeitpunktes eines einen spulenantrieb aufweisenden ventils und ventil
US8960225B2 (en) 2011-05-09 2015-02-24 Continental Automotive Gmbh Method for detecting a closing time point of a valve having a coil drive, and valve
WO2014121982A1 (de) * 2013-02-07 2014-08-14 Robert Bosch Gmbh Verfahren zum betrieb eines kraftstoffeinspritzsystems eines verbrennungsmotors
US10401398B2 (en) 2017-03-03 2019-09-03 Woodward, Inc. Fingerprinting of fluid injection devices
US10712373B2 (en) 2017-03-03 2020-07-14 Woodward, Inc. Fingerprinting of fluid injection devices
DE102017215017A1 (de) 2017-08-28 2019-02-28 Hitachi Automotive Systems, Ltd. Verfahren und Einrichtung zum Betreiben eines elektromagnetisch betätigten Ventils eines Kraftstoffeinspritzers
WO2022090397A1 (de) * 2020-10-30 2022-05-05 Volkswagen Aktiengesellschaft Verfahren zum ermitteln eines schliesszeitpunkts eines injektors mit einem magnetventil, computerprogramm, steuergerät, verbrennungskraftmaschine und kraftfahrzeug

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