Electromagnetic Fuel Injector Closing Instant Detection
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Solution Overview
Problem
Electromagnetic fuel injectors face challenges in precision and consistency when injecting small fuel quantities due to high dispersion in the ballistic area, primarily caused by variations in the magnetic gap thickness, making it difficult to predict the control time for desired fuel quantities, especially when aging phenomena affect the injector's performance.
Innovation Solution
A method to determine the closing instant of an electromagnetic fuel injector with high precision by comparing the voltage time development at the coil ends during injection and a reference voltage time development, allowing for precise estimation of the injected fuel quantity, even in the ballistic area, without requiring significant hardware or computational resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If electromagnetic fuel injectors operate in the ballistic area to inject small fuel quantities (about 1 milligram), then the injection quantity can be reduced to meet emission requirements, but the dispersion of injection features increases significantly making control time unpredictable
Solution Approach 1:
The patent applies feedback by detecting the actual closing instant of the injection valve through voltage signal analysis and using this information to determine the actual injected fuel quantity. The control unit receives feedback about the closing instant from the voltage time development at the coil ends, allowing precise measurement and correction of injection parameters even in the ballistic area where traditional control methods fail.
Solution Approach 2:
The patent replaces mechanical measurement methods with electrical signal analysis. Instead of using mechanical sensors or direct physical measurement of fuel quantity, the system uses voltage time development signals from the coil to detect the closing instant and determine injection characteristics, enabling precise measurement without additional mechanical hardware.
2Measurement precision
If the thickness of the magnetic gap is reduced to reduce dispersion of injection features, then injection precision improves, but manufacturing complexity and cost increase significantly
Solution Approach 1:
The patent changes the approach from controlling physical dimensions (magnetic gap thickness) to controlling and measuring electrical parameters (voltage time development). By monitoring the voltage signals at the coil ends and detecting the closing instant through signal analysis, the system achieves precise injection measurement without requiring tight mechanical tolerances on the magnetic gap, thereby simplifying manufacturing.
Solution Approach 2:
The system uses the existing electrical components (coil and voltage signals) already present in the electromagnetic injector to provide self-diagnosis and measurement of the closing instant. The voltage time development at the coil ends serves as a built-in sensor that automatically provides information about the injection event without requiring external measurement devices or precise mechanical adjustments.
3Measurement precision
If traditional voltage measurement methods are used at the coil ends, then the closing instant detection is insufficiently precise, but more complex hardware and computational resources are required to improve precision
Solution Approach 1:
The patent uses the existing voltage signal at the coil ends as a copy or indicator of the closing event. By analyzing the time development of this existing electrical signal, the system extracts information about the closing instant without requiring duplicate sensing hardware. The voltage signal itself serves as a proxy for the mechanical closing action, enabling precise detection through signal processing rather than direct mechanical measurement.
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 method enables precise determination of the closing instant, enabling accurate estimation of injected fuel quantities, particularly for small quantities, without reducing dispersion or adding costly hardware, thus improving the injector's precision and operational efficiency.
Implementation Method 1
the coil of the electromagnetic actuator is energized so as to generate a magnetic field which attracts the movable armature towards the fixed magnetic pole
Implementation Method 2
detecting a voltage time development at ends of the coil of the electromagnetic actuator after the cancellation of the electric current circulating through the coil
Data Source
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AI summary
Method to determine a closing instant (ts) of an electromagnetic fuel injector (4); in a beginning instant (ti) of the injection, a positive voltage (v) is applied to a coil (16) of an electromagnetic actuator (14) so as to cause an electric current (i) to circulate through the coil (16), said electric current (i) determining the opening of an injection valve (15); in an end instant (t3) of the injection, a negative voltage (v) is applied to the coil (16) of the electromagnetic actuator (14) so as to cancel the electric current (i) circulating through the coil (16); a first voltage time development (v1) is detected at least one end of the coil (16) of the electromagnetic actuator (14) after the cancellation of the electric current (i) circulating through the coil (16); the voltage actuation time development (v1) is compared with a voltage comparison time development (v); and the closing instant (ts) of the electromagnetic injector (4) is determined based on the comparison between the voltage actuation time development (v1) and the voltage comparison time development (v).