Determining the movement behavior over time of a fuel injector on the basis of an evaluation of the chronological progression of various electrical measurement variables

A method for activating a fuel injector having a coil drive for an internal combustion engine of a motor vehicle, the method comprising:

• determining a first time delay defining individual time required for signal conditioning of a first measured signal caused by characteristics of a first electronic circuit for a first electrical measurement variable, wherein determining the first time delay defining individual time required for signal conditioning of the first measured signal includes determining time required for at least one of amplification of the first measured signal,
• determining a second time delay defining individual time required for signal conditioning of a second measured signal caused by characteristics of a second electronic circuit for a second electrical measurement variable,
• applying an electrical excitation to a coil of the coil drive, which results in an opening movement of a valve needle coupled to a magnetic armature of the coil drive,
• recording a chronological progression of the first electrical measurement variable of the coil in response to the electrical excitation,
• determining a time when the opening movement ends based on the recorded chronological progression of the first electrical measurement variable,
• adjusting the determined time of the opening movement ending based upon time individually required for signal conditioning of the first measured signal as defined by the first time delay,
• modifying the electrical excitation of the coil such that the valve needle executes a closing movement,
• recording a chronological progression of the second electrical measurement variable of the coil, and
• determining a time when the closing movement ends based on the recorded chronological progression of the second electrical measurement variable in response to the modified electrical excitation,
• adjusting the determined time of the closing movement ending based upon time individually required for signal conditioning of the second measured signal as defined by the second time delay,
• wherein one of the two measurement variables represents a level of the voltage applied to the coil and the other of the two measurement variables represents a strength of a current that flows through the coil, and
• adapting an electrical activation of the fuel injector based on the time when the opening movement ends and the time when the closing movement ends time, such that a predetermined quantity of fuel is injected using an injection operation.

A device for determining the movement behavior over time of a fuel injector having a coil drive for an internal combustion engine of a motor vehicle, the device comprising:

• an electrical regulating unit configured to apply an electrical excitation to a coil of the coil drive, which results in an opening movement of a valve needle coupled to a magnetic armature of the coil drive,
• a measuring unit configured to record a chronological progression of a first electrical measurement variable of the coil in response to the electrical excitation, and
• a data processing unit configured to:
• determine a first time delay defining individual time required for signal conditioning of a first measured signal caused by characteristics of a first electronic circuit for a first electrical measurement variable, wherein determining the first time delay defining individual time required for signal conditioning of the first measured signal includes determining time required for at least one of amplification of the first measured signal,
• determine a second time delay defining individual time required for signal conditioning of a second measured signal caused by characteristics of a second electronic circuit for a second electrical measurement variable by the second electronic circuit, and
• determine a time when the opening movement ends based on the recorded chronological progression of the first electrical measurement variable,
• adjust the determined time of the opening movement ending based upon time individually required for signal conditioning of the first measured signal as defined by the first time delay,
• wherein the electrical regulating unit is further configured to modify the electrical excitation of the coil such that the valve needle executes a closing movement,
• wherein the measuring unit is further configured to record a chronological progression of the second electrical measurement variable of the coil,
• wherein the data processing unit is further configured to determine a time when the closing movement ends based on the recorded chronological progression of the second electrical measurement variable in response to the modified electrical excitation, and adjust the determined time of the closing movement ending based upon time individually required for signal conditioning of the second measured signal as defined by the second time delay,
• wherein one of the two measurement variables represents a level of the voltage applied to the coil, and the other of the two measurement variables represents a strength of a current which flows through the coil.

An internal combustion engine of a motor vehicle, comprising:

• a fuel injector having a coil drive;
• an engine controller comprising a device for determining the movement behavior over time of the fuel injector, the device comprising:
• an electrical regulating unit configured to apply an electrical excitation to a coil of the coil drive, which results in an opening movement of a valve needle coupled to a magnetic armature of the coil drive,
• a measuring unit configured to record a chronological progression of a first electrical measurement variable of the coil in response to the electrical excitation, and
• a data processing unit configured to:
• determine a first time delay defining individual time required for signal conditioning of a first measured signal caused by characteristics of a first electronic circuit for a first electrical measurement variable, wherein determining the first time delay defining individual time required for signal conditioning of the first measured signal includes determining time required for at least one of amplification of the first measured signal,
• determine a second time delay defining individual time required for signal conditioning of a second measured signal caused by characteristics of a second electronic circuit for a second electrical measurement variable, and
• determine a time when the opening movement ends based on the recorded chronological progression of the first electrical measurement variable,
• adjust the determined time of the opening movement ending based upon time individually required for signal conditioning of the first measured signal as defined by the first time delay,
• wherein the electrical regulating unit is further configured to modify the electrical excitation of the coil such that the valve needle executes a closing movement,
• wherein the measuring unit is further configured to record a chronological progression of the second electrical measurement variable of the coil,
• wherein the data processing unit is further configured to determine a time when the closing movement ends based on the recorded chronological progression of the second electrical measurement variable in response to the modified electrical excitation, and adjust the determined time of the closing movement ending based upon time individually required for signal conditioning of the second measured signal as defined by the second time delay, and
• wherein one of the two measurement variables represents a level of the voltage applied to the coil, and the other of the two measurement variables represents a strength of a current which flows through the coil.