Outward Opening Fuel Injector Needle with Segmented Guide Region
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Solution Overview
Problem
Outward opening fuel injectors for internal combustion engines produce unstable fuel jets that can collapse either towards the piston or the cylinder head, leading to uneven fuel dispersion and poor fuel-air mixing in the combustion chamber, particularly with low-pressure gaseous fuels like hydrogen.
Innovation Solution
A fuel injector design featuring an outward opening injection valve needle with a circumferential fuel guide region, including first and second guide portions that direct fuel at different angles relative to the valve axis, ensuring even dispersion throughout the combustion chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an outward opening fuel injector is used, then the injector structure is simple and reliable, but the fuel jet becomes unstable and collapses towards the piston or cylinder head, leading to uneven fuel dispersion
Solution Approach 1:
The fuel guide region is divided into multiple guide portions (first guide portion, second guide portion, third guide portion) that segment the fuel flow into different directions. Each guide portion directs fuel at a specific angle to create multiple stable jet streams instead of a single unstable jet, resolving the contradiction between simple injector structure and stable fuel dispersion.
Solution Approach 2:
Different guide portions are designed with different geometries and angles to create locally optimized fuel flow characteristics. The first guide portion directs fuel downward at a smaller angle, the second guide portion directs fuel upward at a larger angle, and the third guide portion provides additional flow control, ensuring stable fuel distribution across different regions of the combustion chamber.
2Ease of operation
If fuel is injected towards the lower half of the combustion chamber, then fuel reaches the piston area, but fuel distribution in the upper half near the cylinder head becomes insufficient
Solution Approach 1:
The fuel guide region introduces angular dimensionality to the fuel flow by creating multiple guide portions that direct fuel at different angles (smaller angles downward, larger angles upward). This multi-directional approach ensures fuel reaches both the lower piston area and the upper cylinder head region simultaneously, improving overall fuel-air mixing efficiency while maintaining adequate piston area coverage.
3Device complexity
If a single guide angle is used for fuel injection, then the injector structure is simple, but fuel is not evenly dispersed throughout the entire combustion chamber
Solution Approach 1:
The fuel guide region is segmented into multiple guide portions with different angles to achieve uniform fuel dispersion. This segmentation allows the injector to cover the entire combustion chamber volume without requiring complex external systems, maintaining relative structural simplicity while dramatically improving fuel distribution uniformity through the combined effect of multiple angled jets.
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
The design achieves improved fuel-air mixing and enhanced combustion efficiency by directing fuel to both the lower and upper halves of the combustion chamber, compensating for piston-induced imbalances and ensuring thorough fuel distribution.
Implementation Method 1
the circumferential fuel guide region including a first guide portion defining a first guide surface and a second guide portion defining a second guide surface, wherein the first guide portion is configured to guide fuel injection at a smaller angle with respect to the valve axis V than the second guide portion
Data Source
AI summary
A fuel injector for gaseous fuels, the fuel injector comprising: an injection nozzle having a tip region that is shaped to define an annular valve seat that extends about a central outlet opening; and an outward opening injection valve needle slidably received in the injection nozzle, and operable to move between closed and open positions, the outward opening injection valve needle comprising a valve stem that defines a valve axis and a valve head extending from the valve stem, wherein the valve head comprises: a circumferential sealing region configured to seal against the valve seat and close the central outlet opening in the closed position and to define an annular gap with the valve seat in the open position, and a circumferential fuel guide region that is located downstream from the circumferential sealing region.