Fuel Injector Opening Time Determination via Current Profile Differential
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Solution Overview
Problem
Fuel injectors with coil drives exhibit variations in opening and closing timing and injection amounts due to electrical, magnetic, mechanical, and hydraulic tolerances, leading to relative injection quantity differences that become significant with shorter injection times.
Innovation Solution
A method involving subjecting the magnetic coil drive of a fuel injector to first and second voltage pulses, recording current profiles, determining a difference profile, and identifying the point in time of the predefined open state by finding the extreme value in this profile, which is used to adjust the activation of the fuel injector to minimize injection quantity deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If injection times are shortened to increase productivity, then injection frequency increases, but relative injection quantity differences between injectors become significant and harmful
Solution Approach 1:
The patent applies preliminary action by determining the actual opening time of each injector before normal operation through a calibration process. Voltage pulses are applied and current profiles are recorded to measure the true opening time, which is then stored and used for compensating injection durations in subsequent operations, ensuring consistent injection quantities even with shortened injection times
Solution Approach 2:
The patent implements parameter changes by adjusting the injection duration for each individual injector based on its measured opening time characteristics. The control unit modifies the injection parameters (duration, timing) to compensate for manufacturing tolerances, thereby maintaining consistent injection quantities across all injectors despite variations in their opening/closing behavior
2Ease of manufacture
If individual injector tolerances are accepted to simplify manufacturing, then manufacturing complexity decreases, but injection quantity variations increase and become significant
Solution Approach 1:
The patent applies self-service by enabling each injector to be individually characterized and compensated. The system automatically measures the opening time of each injector during calibration and uses this information to adjust injection parameters specifically for that injector, making the system self-correcting for manufacturing tolerances without requiring manual adjustment or higher precision manufacturing
Solution Approach 2:
The patent implements feedback by using the measured current profiles and determined opening times to continuously adjust and optimize injection parameters. The control unit uses the recorded characteristics of each injector to provide real-time compensation, ensuring that injection quantities remain consistent despite variations in injector performance
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 effectively compensates for tolerances, ensuring consistent injection quantities across fuel injectors by accurately determining the point in time of the open state and adjusting the activation parameters, thereby reducing relative differences in injection amounts.
Implementation Method 1
subjecting the magnetic coil drive of the fuel injector to a first voltage pulse
Implementation Method 2
recording a first time profile of the current level of a current flowing through the coil drive
Data Source
AI summary
A method is provided for determining the point in time of a predetermined open state (e.g., start or stop time of an opening or closing process) of a fuel injector having a coil drive for an internal combustion engine of a motor vehicle. The method includes applying a first voltage pulse to the magnetic coil drive of the fuel injector, detecting a first temporal progression of the current intensity of a current flowing through the coil drive, applying a second voltage pulse to the magnetic coil drive of the fuel injector, detecting a second temporal progression of the current intensity of the current flowing through the coil drive, determining a differential progression based on the first and second temporal progressions of the current intensity, and determining a point in time at which the differential progression exhibits an extremum, which corresponds with the point in time of the predetermined open state.