Fuel Injector Control Using Preload Calibration
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Solution Overview
Problem
Existing fuel injector control methods fail to achieve precise and consistent fuel injection volumes across different injectors, leading to variations in engine performance and increased gas emissions due to dispersion in injection volumes.
Innovation Solution
A method and device for controlling fuel injectors that adjust the opening time length of the valve needle based on the injector-specific preload force, using a calibration value to determine a set-point opening time length, which reduces dispersion by accounting for individual injector characteristics and manufacturing settings, ensuring precise fuel injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a fixed opening time length is used for all injectors, then the control system is simple, but the injection volume varies significantly between injectors due to manufacturing tolerances in preload force
Solution Approach 1:
The patent applies parameter changes by adjusting the opening time length parameter based on the individual preload force characteristics of each injector. Instead of using a fixed opening time for all injectors, the control unit determines injector-specific opening times by modifying the base opening time according to the actual preload force measured during calibration, thereby compensating for manufacturing variations and achieving precise injection volumes.
Solution Approach 2:
The patent implements preliminary action by performing calibration of each injector during the manufacturing process. The preload force is measured and stored as calibration data before the injector is installed in the engine. This preliminary characterization allows the control system to apply compensating adjustments in normal operation without requiring complex real-time measurements.
2Measurement precision
If injector-specific calibration is performed for each injector, then injection volume precision is improved, but the calibration process becomes more time-consuming and complex
Solution Approach 1:
The calibration process is performed as a preliminary action during manufacturing rather than during installation or operation. The preload force is measured and stored as calibration data in advance, allowing quick reference during normal operation without time-consuming real-time measurements.
Solution Approach 2:
The patent replaces complex mechanical calibration procedures with a simplified electrical measurement system. The preload force is determined by measuring the electrical characteristics (current, voltage, or impedance) of the actuator assembly, which correlates with the mechanical preload force. This substitution reduces calibration complexity and time while maintaining precision.
3Manufacturing precision
If the preload force is adjusted during manufacturing for a given injection volume, then the injection precision at that specific set-point is improved, but the precision deteriorates at other set-points due to non-linear relationships
Solution Approach 1:
The patent applies dynamics by making the opening time length adaptive rather than fixed. The control unit dynamically adjusts the opening time based on the actual preload force measured during calibration and the desired injection volume. This dynamic adjustment compensates for non-linear relationships between preload force and injection volume across different operating conditions, maintaining precision at multiple set-points.
Solution Approach 2:
The system changes the opening time parameter dynamically based on both the individual injector characteristics (preload force) and the operating conditions (desired injection volume). This dual-based parameter adjustment allows the system to maintain precise control across varying set-points rather than being optimized for a single condition.
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 significantly reduces the dispersion of fuel injection volumes between injectors, minimizing the risk of uneven air/fuel mixtures and enhancing engine performance while adhering to stringent emission regulations.
Implementation Method 1
a spring element being designed and arranged to exert a preload force on the valve needle acting to urge the valve needle in the closed position
Implementation Method 2
The actuator assembly may be a piezoelectric actuator assembly or an electromagnetic actuator assembly
Implementation Method 3
The actuator assembly may be a piezoelectric actuator assembly or an electromagnetic actuator assembly
Data Source
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AI summary
A method is disclosed for controlling an injector of a combustion engine. The injector comprises an injection valve housing with an injection valve cavity, a valve needle being axially movable within the injection valve cavity, a valve seat, on which the valve needle rests in a closed position and from which the valve needle is lifted for an open position, a spring element being designed and arranged to exert a preload force (PF) on the valve needle acting to urge the valve needle in the closed position. A calibration value (CV) is provided, which is representative for the preload force (PF). A base quantity (BOT) is provided correlated to the fluid volume to be dispensed by the injector. Dependent on the calibration value (CV) and the base quantity (BOT), a set-point opening time length (SOT) is determined. The valve needle of the injector is controlled to be in the opening position correlated to the set-point opening time length (SOT).