Fuel Injection Valve Non-Circular Nozzle Geometry
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Solution Overview
Problem
Conventional fuel injection valves face issues with deposit accumulation on nozzle hole inner walls and chronological changes in fuel injection characteristics, leading to interference between fuel sprays, negative pressure formation, and degradation of spraying characteristics.
Innovation Solution
The fuel injection valve incorporates non-circular nozzle holes with a ratio of longest to shortest diameter greater than 1, along with specific geometric configurations to prevent deposit accumulation and interference between sprays, ensuring proper air intake and maintaining spraying characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional circular nozzle holes are used, then manufacturing is simple, but deposit accumulation occurs on nozzle hole inner walls and fuel injection characteristics deteriorate over time
Solution Approach 1:
The patent applies asymmetry by changing the nozzle hole cross-sectional shape from circular to non-circular (oval, elliptical, or rectangular). This asymmetric geometry prevents fuel from stagnating at corners and ensures uniform fuel flow distribution along the inner wall, effectively suppressing deposit accumulation while maintaining manufacturing feasibility through standard machining or molding processes.
2Productivity
If multiple nozzle holes are arranged closely to increase injection density, then fuel injection efficiency improves, but negative pressure forms and spray interference occurs
Solution Approach 1:
The non-circular nozzle hole geometry creates asymmetric spray patterns that diverge at optimized angles, reducing spray-spray interference even when multiple nozzles are closely spaced. The elongated cross-section directs fuel streams in a manner that prevents negative pressure formation between adjacent sprays, enabling higher injection density without harmful interactions.
Solution Approach 2:
The patent transitions from circular (one-dimensional symmetry) to non-circular (two-dimensional asymmetric) nozzle hole geometry, adding a dimensional aspect to spray control. This allows independent optimization of spray angle and distribution pattern in different planes, enabling efficient close-spaced nozzle arrangements without spray interference.
3Productivity
If nozzle holes are enlarged to improve fuel flow, then injection rate increases, but spray characteristics and atomization quality deteriorate
Solution Approach 1:
The non-circular cross-section allows the nozzle hole area to be increased while maintaining optimized aspect ratios that preserve spray atomization quality. The elongated geometry provides increased surface area for fuel distribution without proportionally increasing the hydraulic diameter, enabling higher flow rates with maintained or improved spray characteristics compared to circular holes of equivalent area.
Data Source
AI summary
At least one of nozzle holes is provided as a non-circular nozzle hole where the ratio of the longest diameter to the shortest diameter of an outlet opening portion is greater than 1. A virtual non-circular cone and a virtual circular cone are defined for each of the non-circular nozzle hole and a circular nozzle hole where the ratio of the longest diameter to the shortest diameter of the outlet opening portion is 1. At least two adjacent nozzle holes are formed such that the virtual non-circular cone does not interfere with the virtual circular cone or the virtual non-circular cone.