Fuel Injector Actuation Device Tolerance Compensation
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Solution Overview
Problem
In internal combustion engines, the ballistic operating mode of fuel injectors is significantly affected by electrical and mechanical tolerances, leading to inaccuracies in fuel injection, which existing compensation methods fail to accurately account for the feedback signal acquisition tolerance, resulting in suboptimal fuel measurement accuracy.
Innovation Solution
An actuation device comprising an output stage, measuring unit, and control and evaluation unit that generates a test pulse to measure and evaluate the response pulse, allowing for the identification of characteristic features and compensation of measuring channel errors, thereby improving the accuracy of injector movement behavior and fuel injection quantity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If individual measurement and compensation of injector voltage profile is performed, then injector tolerance compensation is improved, but feedback signal acquisition tolerance is not accurately accounted for
Solution Approach 1:
The patent performs preliminary characterization of the measuring channel by injecting test pulses before actual fuel injection measurements. This preliminary action determines the impulse response and identifies systematic errors in the measuring channel, allowing these errors to be compensated for in subsequent measurements. The measuring channel impulse response is stored and used to correct feedback signals obtained during ballistic injection operations.
Solution Approach 2:
The patent utilizes the feedback signal generated by eddy currents between the injector mechanics and magnetic circuit as a measurement signal. By characterizing how the measuring channel affects this feedback signal through test pulses, the system creates a feedback loop that allows correction of measurement errors. The identified characteristic features of the impulse response are used to compensate for systematic errors in actual injection measurements.
2Productivity
If ballistic operating mode is used with small injection quantities, then fuel injection efficiency is improved, but tolerance influence on movement profile increases significantly
Solution Approach 1:
The patent introduces test pulses as an intermediary measurement tool to characterize the measuring channel's effect on feedback signals. These test pulses serve as a mediator between the known electrical input and the measured feedback signal, allowing the system to identify and compensate for systematic errors in the measurement chain without affecting the actual fuel injection process.
Solution Approach 2:
The patent changes the electrical parameters of the actuation signal by superimposing test pulses with varying amplitudes and durations on the normal actuation signal. This allows the system to probe the measuring channel's response characteristics at different parameter levels, enabling accurate characterization of the measurement system's behavior under various operating conditions.
3Manufacturing precision
If full stroke mode is used, then tolerance influence is reduced, but injection quantity flexibility is limited
Solution Approach 1:
The patent replaces direct mechanical measurement of needle position with an electrical measurement approach using feedback signals from eddy currents. This substitution allows for non-contact, high-resolution measurement of the needle's movement profile, enabling accurate characterization of ballistic injection modes where mechanical tolerances would otherwise dominate the measurement uncertainty.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables precise compensation of injector tolerances and movement behavior, enhancing the accuracy of fuel injection, particularly in the ballistic mode, by accurately determining the influence of the measuring channel on the feedback signal, leading to improved quantity accuracy and reduced errors.
Implementation Method 1
an unavoidable feedback signal occurs at coil-operated assemblies, which feedback signal depends, by means of a coupling driven by an eddy current, between the mechanics of the injector (armature and injector needle) and the magnetic circuit (coil) of the injector
Implementation Method 2
a feedback signal depends, by means of a coupling driven by an eddy current, between the mechanics of the injector (armature and injector needle) and the magnetic circuit (coil) of the injector
Data Source
AI summary
The present disclosure generally relates to internal combustion engines. The teachings thereof may be embodied in methods for the measuring of a feedback signal generated by the movement dynamics of a fuel injector in operation. A method may include: (a) generating an electrical test pulse; (b) feeding the test pulse into an actuation line connecting the output stage to the injector to an electric drive of the injector; (c) measuring an electrical response pulse generated by the actuation line in response to the test pulse; (d) identifying a characteristic feature of the measured response pulse; (e) transferring the feature to a control and evaluation unit; (f) evaluating the feature; and (g) acquiring the characteristic information item about the measuring channel based on the evaluation of the transferred characteristic feature.