Fuel Injector Valve Needle Vibration Control
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Solution Overview
Problem
The existing fuel injectors face challenges in accurately controlling the quantity of fuel injected during multiple injections due to vibrations of the valve needle, leading to variations in opening delays and difficulties in engine development.
Innovation Solution
A valve needle with a reduced natural frequency of vibration, achieved by adding a mass of at least 1.5 grams in the vicinity of the needle head, made of high-density materials like steel or tungsten carbide, to control the fuel injection quantity and minimize hydraulic separation between successive injections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the natural frequency of the valve needle is high (prior art: 26.7 kHz), then the valve needle responds quickly to injection commands, but the valve needle vibrates excessively during multiple injections causing variable opening delays and inaccurate fuel quantity control
Solution Approach 1:
The patent changes the natural frequency parameter of the valve needle from 26.7 kHz to below 20 kHz by adding mass (at least 1.5 grams) in the vicinity of the needle head. This parameter change reduces vibration amplitude during multiple injections while maintaining adequate response speed, thereby improving fuel quantity control accuracy during sequential injections
Solution Approach 2:
The patent segments the valve needle structure by adding a separate mass element (at least 1.5 grams) in the vicinity of the needle head. This segmentation allows independent optimization of the needle's dynamic characteristics, reducing vibration during multiple injections while preserving the needle's functional integrity
2Reliability
If mass is added to reduce the natural frequency of the valve needle, then vibration is reduced for better multiple injection control, but the overall mass of the valve needle increases
Solution Approach 1:
The patent applies local quality by concentrating the added mass (at least 1.5 grams) specifically in the vicinity of the needle head rather than distributing it uniformly. This localized mass addition effectively reduces the natural frequency and suppresses vibration during multiple injections while minimizing the overall mass increase of the valve needle
3Manufacturing precision
If software compensation is used to adjust fuel injection quantity, then injection quantity can be controlled, but the system complexity increases and cannot fully compensate for vibration-induced timing variations
Solution Approach 1:
The patent converts the harmful vibration of the valve needle into a beneficial low natural frequency characteristic (below 20 kHz) that actually suppresses excessive vibration during multiple injections. This physical solution eliminates the need for complex software compensation, reducing control system complexity while improving injection quantity precision
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 solution enables precise control of fuel injection, improving combustion efficiency by reducing the natural frequency of the valve needle and minimizing opening delays between injections.
Implementation Method 1
The valve needle has a natural frequency of vibration which is calculated in the recessed mode on a valve seat arranged in the nozzle body. The natural frequency F14 is lower than the natural frequency F114 of vibration of a valve needle of the prior art
Data Source
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AI summary
To reduce emissions and improve the performance of internal combustion engines with fuel injection, multiple injections are performed during an engine operating cycle. The object of the present invention is to provide a solution by achieving better control of the injected quantity with very low hydraulic separation between two successive injections, thus improving combustion. A valve needle (14) of a fuel injector (10) extends along a longitudinal axis (X) between a needle head (28) and a needle tip (30). The valve needle (14) has a natural frequency (F14) of vibration at least 1.3 times lower than the natural frequency (F114) of vibration of a prior art valve needle (114) adapted to be arranged in the fuel injector. One possibility is that the valve needle (14) includes an additional component (24) added in the vicinity of the needle head (28).