Fuel Injector Series Annular Gap Throttle Segmentation
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Solution Overview
Problem
Existing fuel injector designs require tight manufacturing tolerances for the gap width of hydraulic throttle elements to ensure proper closing of the nozzle needle, which is sensitive to manufacturing inaccuracies and particle contamination.
Innovation Solution
The implementation of multiple annular gap throttle elements in series reduces the sensitivity to gap width variations, allowing for larger gap dimensions and thus less stringent manufacturing requirements, while also mitigating the impact of particles in the fuel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a single annular gap throttle element is used with a very small gap width to ensure proper closing force, then the closing force is sufficient, but the manufacturing tolerances must be very tight and the sensitivity to particles is high
Solution Approach 1:
The single annular gap throttle is segmented into multiple annular gap throttle elements arranged in series. This segmentation allows each individual gap to be larger while maintaining the overall throttling effect through the cumulative resistance of multiple gaps, thereby reducing manufacturing tolerance requirements for each gap while preserving the necessary closing force.
2Force
If a very small gap width is used in the annular gap throttle, then the closing force is sufficient, but the sensitivity to particles carried along in the fuel is increased
Solution Approach 1:
By dividing the throttle into multiple annular gap elements in series, each gap can be designed with a larger width that is less sensitive to particle blockage. The cumulative throttling effect of multiple larger gaps achieves the required closing force while reducing the harmful effect of fuel-borne particles on any single gap.
3Manufacturing precision
If larger gap widths are used in annular gap throttle elements, then the manufacturing accuracy requirements are reduced, but the closing force may be insufficient
Solution Approach 1:
Multiple annular gap throttle elements are merged in series to achieve the cumulative throttling effect. The combined resistance of several larger gaps equals or exceeds that of a single small gap, thereby maintaining sufficient closing force while allowing larger individual gap dimensions that reduce manufacturing accuracy requirements.
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 design enhances the robustness of the hydraulic throttling mechanism, reducing the need for precise manufacturing and minimizing the effect of fuel-borne particles, leading to improved reliability and performance.
Implementation Method 1
hydraulic throttling to form a closing force acting on the nozzle needle
Implementation Method 2
there is a pressure difference between the two pressure chambers, which ensures that the nozzle needle closes quickly
Data Source
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AI summary
The invention relates to a fuel injector for internal combustion engines, having a pressure chamber (16) formed in a housing (10), in which a nozzle needle (15) is disposed having an adjustable stroke. The pressure chamber (16) is divided into a stored pressure chamber (26) away from the nozzle needle seat and a nozzle needle pressure chamber (25) near the nozzle needle seat, wherein a hydraulic throttle element (40) designed as an annular gap throttle is disposed between the stored pressure chamber (26) and the nozzle needle pressure chamber (25). At least two annular gap throttle elements (41.1 to 41.n) are disposed one after another in the fuel flow direction at the nozzle needle (15).