Fuel Injector Nozzle Sac Outlet Segmentation for Hydrogen
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Solution Overview
Problem
Delivering gaseous fuel, such as hydrogen, evenly into an internal combustion engine cylinder is challenging due to varying injection pressure and the need to minimize actuation forces, especially with gaseous fuels like hydrogen which have limited lubricating properties.
Innovation Solution
The injector nozzle design features a valve needle with a fuel guiding region and multiple sets of nozzle outlets distributed around a sac, minimizing the valve seat diameter while ensuring even fuel distribution through a balanced flow area, using a neiloidic frustum-shaped fuel guiding region to redirect fuel flow and counteract flow instability at low needle lifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the valve seat diameter is minimized to reduce actuation forces, then the actuation forces required to operate the fuel injector are reduced, but the flow area for fuel delivery is reduced
Solution Approach 1:
The nozzle outlets are segmented into two distinct rows: a first row of openings in the sac wall and a second row of openings in the sac wall. This segmentation allows the fuel flow path to be divided into multiple stages, first through the valve seat and then through both rows of openings, effectively increasing the total flow area without increasing the valve seat diameter.
Solution Approach 2:
The patent utilizes the three-dimensional space within the sac by arranging nozzle outlets in two different rows at different positions within the sac volume. This spatial arrangement in multiple dimensions allows increased flow area without proportionally increasing the valve seat diameter, as fuel can access outlets through multiple spatial pathways.
2Quantity of substance
If gaseous fuel is delivered at high pressure to ensure sufficient fuel delivery, then the fuel delivery quantity is increased, but the fuel distribution evenness is reduced
Solution Approach 1:
By dividing the nozzle outlets into two rows distributed around the sac, the fuel flow is segmented into multiple distribution pathways. This segmentation ensures that fuel is delivered to multiple locations around the combustion cylinder simultaneously, improving distribution evenness while maintaining high total fuel delivery quantity through the combined flow area of both rows.
Solution Approach 2:
The two rows of openings are positioned at different locations within the sac, creating locally optimized flow paths. The first row openings and second row openings provide different flow characteristics to different regions of the combustion cylinder, ensuring even overall distribution while maintaining high fuel delivery quantity through the cumulative effect of both rows.
3Quantity of substance
If the injection pressure is increased to compensate for varying tank pressure, then the fuel delivery quantity is maintained, but the actuation forces required are increased
Solution Approach 1:
The segmented two-row nozzle outlet configuration allows the system to maintain adequate fuel delivery quantity through multiple flow paths rather than relying on a single large flow area that would require higher actuation forces. The distributed openings provide cumulative flow area that sustains fuel delivery at lower actuation forces.
Solution Approach 2:
By utilizing three-dimensional spatial arrangement of outlets in two rows within the sac, the patent creates multiple flow pathways that collectively provide sufficient flow area without requiring proportionally high actuation forces. The spatial distribution allows fuel to reach outlets through various paths, maintaining delivery quantity with reduced force requirements.
Data Source
AI summary
An injector nozzle of a fuel injector for an internal combustion engine comprises a valve needle, and a nozzle body extending along a longitudinal axis from a tip, at a proximal end, to an opposing distal end for connection to the fuel injector. The nozzle body is provided with a bore within which the valve needle is moveable; and a valve seat defined at a proximal end of the bore and transitioning into a sac that defines a sac volume. The valve needle is moveable relative to the valve seat to control fuel delivery through a first set of nozzle outlets and a second set of nozzle outlets. The valve needle includes a seat region and a fuel guiding region extending proximally from the seat region.