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
  • F02D41/26—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means using computer, e.g. microprocessor
  • F02D41/28—Interface 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
  • F02D41/30—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
  • 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
  • F02D41/24—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means
  • F02D41/26—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means using computer, e.g. microprocessor
  • F02D41/28—Interface circuits
  • F02D2041/281—Interface circuits between sensors and control unit
• • 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
  • F02D2200/0602—Fuel pressure
• • 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
  • F02D2250/00—Engine control related to specific problems or objectives
  • F02D2250/16—End position calibration, i.e. calculation or measurement of actuator end positions, e.g. for throttle or its driving actuator
• • 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
  • 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
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T10/00—Road transport of goods or passengers
  • Y02T10/10—Internal combustion engine [ICE] based vehicles
  • Y02T10/40—Engine management systems

Definitions

• the present invention relates to a method for determining a characteristic point in time of an injection process caused by activation of a fuel injector, and to a computing unit and a computer program for carrying it out.
• Modern internal combustion engines have fuel injectors, with which fuel can be selectively introduced into combustion chambers.
• characteristic points in time of the injection processes in particular opening and closing of the injection valves of the fuel injectors, must be detected as accurately as possible.
• the electrical quantities of the drive i.e., the detection of such characteristic times, can often be used. essentially energizing the actuator, to be used.
• a method according to the invention serves to determine a characteristic point in time of an injection process caused by activation of a fuel injector of an internal combustion engine by means of a sensor which is provided to detect an opening and / or closing of the fuel injector.
• a signal of the sensor is detected, and formed from the signal of the sensor, a correction signal to reduce or completely avoid an effect of the control on the sensor signal, in particular by crosstalk.
• a start of the control is used as a time reference point for the correction signal, in particular as the beginning of the correction signal, and a signal difference between the sensor signal and the correction signal is formed, from which the characteristic point in time of the injection process is concluded.
• the correction signal can be formed from and preferably beginning with the rising edge of the sensor signal, which occurs essentially simultaneously with the start of the activation.
• the tax start is in the Usually known, whereby also the corresponding rising edge of the sensor signal or its temporal position can be identified. If the start of the control is not known exactly, then, for example, the corresponding rising edge or its temporal position can be determined by searching for the greatest slope of the sensor signal in a presumed period of the start of control.
• the sensor line of such a sensor is usually aimed at between the fuel injector and the control unit as well as the control lines for the fuel, which are usually twisted together. To move the ejector geometrically parallel with a small distance from each other. This results in coupling capacitances between the control lines and the sensor line. By overcoupling when driving the fuel! However, the detection of characteristic points in time by means of the sensors can be disturbed if the switching operations in the control device are in temporal proximity to these points in time. Such couplings on a signal of the sensor can lead, for example, to incorrectly recognized opening or closing times.
• overcouplings or couplings can be removed from the signal of the sensor by forming a suitable correction signal which corresponds as far as possible to the interference signal due to the overcouplings and is then subtracted from the signal of the sensor.
• a suitable correction signal which corresponds as far as possible to the interference signal due to the overcouplings and is then subtracted from the signal of the sensor.
• an amplitude of the correction signal is determined from a first value of the sensor signal before and a second value of the sensor signal after the start of the activation, preferably as a difference of these values.
• the first value comprises an extreme value (maximum or minimum), an average value or a median value of the signal in a predetermined first time interval before the start of the activation and / or the second value an extreme value (maximum or minimum), an average value or a median value of the signal in a predetermined second time interval after the start of the drive.
• the correction signal comprises a square wave signal. This is a particularly simple way of emulating the interference signal without large
• Boost voltage approximately rectangular.
• the correction signal comprises a trapezoid signal with a slope which corresponds to the slope of the sensor signal in a predetermined third time interval after the start of the activation. This allows a more accurate replica of the interfering signal and thus a good signal from the sensor, at which a characteristic point in time can be detected.
• a profile of the rising edge of the sensor signal is determined and used as the course of a rising edge of the correction signal and / or inverted as the course of a falling edge of the correction signal. This represents a particularly accurate possibility of simulating the interference signal and therefore allows a very accurate compensation of the interference signal.
• a time duration of the correction signal is determined taking into account a predetermined, in particular a boost duration corresponding to a triggering time of the fuel injector.
• a boost duration corresponding to a triggering time of the fuel injector is essentially the same for each triggering operation, so that, for example, an average or, for example, predetermined boost duration can be used as the duration for the correction signal.
• a time duration of the correction signal taking into account a falling edge of the sensor signal after the start of control and / or a curve and / or a switching time of a voltage for the
• Boost control of the fuel injector set represent further improvements for the best possible coordination of the duration of the correction signal over the duration of the interference signal.
• the falling edge of the signal in particular the time with the steepest slope, is taken into account, the actual end of the interference signal can be taken into account.
• the duration of the interference signal which indeed corresponds to a cross-coupling of the voltage for the control to the signal of the sensor, are detected very accurately. If a switching time, for example, a final stage, which provides the voltage for the control, can be tapped, a very accurate duration of the interference signal can also be determined from this.
• the characteristic time comprises opening of the fuel injector.
• the boost voltage at the start of control leads to a
• Interference signal in the signal of the sensor which can overlap in time with the opening of the fuel injector and thus a corresponding voltage change in the signal of the sensor. At other characteristic times such as a needle reversal in the fuel injector or a closing of the fuel injector such overlaps are usually not or hardly present. In addition, the interference signals at these times are also significantly lower, if any exist. It is advantageous if the correction signal and / or the signal difference are formed digitally after processing of the signal by an analog-to-digital converter. Processing of a signal as described above is particularly easy if the signal is digital.
• the signal from the sensor can be processed further, for example the above mentioned
• Parameters such as amplitude and duration are determined, still pass through a low-pass filter. This can be used to remove other, irrelevant interference signals.
• piezoresistive sensor or an inductive sensor used Piezoelectric sensors are usually in such fuel! injectors used sensors. As sensors, however, for example, piezoresistive or inductive sensors can be used. Whereas piezoelectric sensors actively release charge during mechanical excitation, piezoresistive sensors change their ohmic resistance.
• the fuel comprises! Njektor a servo-valve, in particular a solenoid servo valve or a piezo-servo valve.
• Njektor a servo-valve, in particular a solenoid servo valve or a piezo-servo valve.
• An arithmetic unit according to the invention for example a control unit, in particular an engine control unit, of a motor vehicle is, in particular programmatically, adapted to carry out a method according to the invention.
• the implementation of the method in the form of a computer program is advantageous because this causes very low costs, especially if an executive controller is still used for other tasks and therefore already exists.
• Suitable data carriers for providing the computer program are in particular magnetic, optical and electrical memories, such as eg hard disks, flash memory, EEPROMs, DVDs, etc. It is also possible to download a program via computer networks (Internet, Intranet, etc.).
• Figure 1 shows schematically a circuit arrangement for a fuel injector with solenoid and associated sensor.
• FIGS. 2a to 2c show equivalent circuit diagrams for a sensor and a sensor circuit.
• FIG. 3 shows schematically a circuit arrangement for a fuel injector with associated sensor.
• FIGS. 4a and 4b show equivalent circuit diagrams for the circuit arrangement according to FIG. 3.
• FIG. 5 shows characteristics of a coil voltage and of potentials at the high side and low side when triggering a fuel injector solenoid coil.
• FIG. 6 shows curves of potentials at the high side and low side and a signal from the sensor during activation of a fuel injector
• Magnetic coil and associated sensor Magnetic coil and associated sensor.
• FIG. 7 shows curves of potentials at high side and low side and a signal from the sensor when triggering a fuel! with the injector Magnetic coil and associated sensor and a correction signal according to a method of the invention in a preferred embodiment.
• FIG. 1 shows by way of example a circuit arrangement for a first fuel injector 110 with a magnetic coil 15 and associated sensor 120.
• the fuel injector 1 10 is associated with an internal combustion engine 100.
• the solenoid coil 1 15 serves as a solenoid for controlling a servo-solenoid valve in the fuel! injector 1 10.
• the sensor 120 is in the fuel! Njektor 1 10 arranged such that, for example, a pressure in a control chamber, which can be opened by means of the servo-solenoid valve, can be detected.
• the magnetic coil 1 15 is connected to two drive lines, a high-side line HS and a low-side line LS to an output stage 155 of a designed as a motor control unit 150 arithmetic unit.
• the high-side line HS and the low-side line LS are each connected to ground via a capacitor (eg with capacities of 4.7 nF for low-side and an integer multiple of 4.7 nF for high-side) tethered.
• the sensor 120 for example, a piezoelectric sensor with a piezo element, is connected via two inputs to the engine control unit 150, wherein one of these inputs via the housing of the fuel! Njektors 1 10 and the internal combustion engine 100 is connected to the negative pole of a vehicle battery 105 or to ground.
• the sensor 120 is connected in parallel to an input capacitance C in , followed by an input circuit 160, a positive voltage of, for example, +5 V, and an analog-to-digital converter 161.
• the input circuitry 160 may include resistors and capacitance as shown. However, the exact configuration of this input circuit for the present invention is not relevant and therefore will not be described in more detail.
• the arrangement or circuit shown in FIG. 1 is one which is already used for conventional injection processes and recognition of characteristic times of such injection processes.
• FIG. 2a an equivalent circuit diagram for the sensor 120, which is shown on the left-hand side, is shown on the right-hand side.
• the sensor 120 may therefore be considered as a current source i Se ns, which emits an electrical charge that is proportional to a force F which acts on the sensor 120.
• D 3 3 is the relevant piezoelectric coefficient and dF / dt is the time derivative of force F on the sensor.
• This electric charge charges a capacitor having the self-capacitance C s ns of the sensor 120.
• FIG. 2b shows an equivalent circuit diagram for the sensor and the associated sensor circuit, which is already shown in FIG. In contrast to the circuit arrangement of sensor 120 and associated input circuit 160 in the engine control unit, only the sensor 120 is replaced by the equivalent circuit shown in FIG. 2a.
• FIG. 2c shows a further simplification of the equivalent circuit diagram from FIG. 2b.
• Ui d33-F / (Csens + C in ).
• the circuitry for the sensor 120 is easier to understand.
• the circuit arrangement of Figure 1 is shown again, wherein for the sake of simplicity instead of the fuel sensor 1 10 only for the circuit arrangement relevant magnetic coil 1 15 is shown.
• capacitors C H s and C L s are now entered, which represent the coupling between the high-side and low-side lines HS and LS and the sensor line for the sensor 120.
• FIG. 4 a shows an equivalent circuit diagram for the parts relevant for the wiring of the sensor 120 from the circuit arrangement of FIG. 3.
• the capacitances C H s and C L s are each connected to the associated voltage source U H s and Ui_s, which represent the voltages applied to the magnetic coil 15 by the output stage 155, to the circuitry shown in FIG. 2 c.
• a boost voltage usually between 40 V and 50 V
• u H s can also assume the value of the battery voltage. Due to these overcoupling, the recognition of characteristic points in time can be disturbed when switching operations in the engine control unit are in temporal proximity to these times. This is the case in particular when opening the servo valve, since the boosting is ended in close temporal proximity to it and therefore, the voltage u H s jumps from the boost voltage, ie, between 40 V and 50 V to zero or to battery voltage.
• FIG. 5 shows curves of a coil voltage U S in the magnet coil and of voltages or potentials U H s on the high side and U L s on the low side in the case of activation of a fuel injector solenoid, as shown in FIG. In each case, a voltage U in volts is plotted against the time t in ms.
• the potentials U H s and U L s are typically generated by a final stage, as shown in Figure 1, in a control of a fuel injector for injecting fuel.
• the coil voltage U S is the resulting voltage from these potentials, applied to the solenoid.
• a boost voltage of approx. 40 V is first applied to the coil for approx. 0.1 ms.
• the coil voltage between the vehicle electrical system voltage, which is about 14 V, and the voltage zero of the coil current within a Hysteresestrombandes regulated.
• the activation of the magnetic coil is terminated by raising the potential U L s to the boost voltage, so that the coil current is rapidly reduced and the fuel injector closes again.
• curves of the potentials U H s and U L s are shown in FIG.
• a signal U s of a sensor such as that of the sensor 120 from FIG. 1 is shown when the magnet coil is driven with the potentials U H s and U L s.
• a voltage U in volts is plotted against a time t in ms.
• the signal Us can be, for example, by means of the input circuit 160 and the A D
• the potential U L s does not cause significant couplings on the signal U s . Furthermore, in the other relevant time periods, namely the needle reversal and the
• FIG. 7 shows the curves of the potentials U H s and U L s and of the signal U s, as shown in FIG. Further, a correction signal U K as well as a cor- gATORs signal or a signal difference U 's, which corresponds to a difference between the
• the signal U s for example, converted by means of the A / D converter 161 into a digital signal, it can be suitably analyzed.
• the amplitude of the interference signal can be determined.
• the signal U s can be examined for its lowest and highest value.
• This difference of 0.7 V can now be used as the amplitude for a correction signal U K , which can be subtracted by suitable processing of the signal U s .
• the activation start t 0 ms is used.
• the time duration of the correction signal U K can be the typical duration of the boost control, which in the present case is 0.1 ms, for example. This can be formed in the simplest case, a rectangular signal, as shown as signal U K in Figure 7.
• the shape of the correction signal U K can also be adapted more precisely to the interference coupling, as has been described in several variants at the outset.

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

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• 2015
  • 2015-06-30 DE DE102015212119.4A patent/DE102015212119A1/de active Pending
• 2016
  • 2016-06-01 KR KR1020187002458A patent/KR102469640B1/ko active IP Right Grant
  • 2016-06-01 CN CN201680038765.1A patent/CN107787401B/zh active Active
  • 2016-06-01 WO PCT/EP2016/062365 patent/WO2017001134A1/de active Application Filing

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