Fuel Injector Variable Dosage via Segmented Spindle
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Solution Overview
Problem
Current fuel injectors for two-stroke internal combustion engines lack variable dosage capabilities to optimize heat release and reduce emissions, particularly NOx and HC particles, due to fixed injection hole openings and additional volume between nozzle holes and valve walls.
Innovation Solution
A sliding injection valve within the atomizer controls the direct opening and closing of injection holes without additional volume, allowing stepwise opening of nozzle holes for variable fuel injection, controlled by a spindle with a cut-off element that adjusts fluid communication with nozzle bores.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional fuel injector design with additional volume between nozzle holes and valve walls is used, then the structure is simpler, but variable dosage capabilities are lost and emissions (NOx and HC particles) increase
Solution Approach 1:
The injection valve is segmented into multiple spindles (first spindle with first valve portion, second spindle with second valve portion) that can independently control different sets of injection holes. This segmentation enables variable dosage capabilities by selectively opening/closing different hole groups while managing the complexity through modular valve control architecture.
2Measurement precision
If the valve spindle directly controls nozzle hole opening without additional volume, then injection precision improves, but the valve guide and atomizer structure becomes more complex
Solution Approach 1:
The valve guide is nested within the atomizer body, with the spindle moving axially within the valve guide's longitudinal bore. The cut-off element is nested within the atomizer's longitudinal bore to directly control nozzle hole openings. This nested arrangement achieves precise injection control while integrating multiple functions into compact, space-efficient structures.
3Adaptability or versatility
If multiple spindles are used to control different injection hole rows, then injection flexibility improves, but the control system complexity increases
Solution Approach 1:
A control valve body serves as an intermediary between the control system and the multiple spindles. It contains separate control chambers (first control chamber, second control chamber) that independently regulate the first and second spindles respectively. This intermediary structure manages the complexity of multi-spindle control by providing dedicated control pathways for each spindle while enabling flexible injection patterns.
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 injection rates, reduces NOx formation, and decreases HC emissions by allowing flexible control of heat release and injection cross-sections, improving fuel efficiency and design simplicity.
Implementation Method 1
Movement of the valve needle away from the seating into a first fuel injecting position causes the chamber to communicate with the first annular recess to permit fuel delivery through the first outlet opening
Implementation Method 2
When the valve spindle is open, the lower row of inlet openings is supplied by fuel flowing through a central duct of the cut-off element and the upper row of inlet openings is supplied by fuel flowing in an annular passage defined between the inner wall of the atomizer bore and the outer surface of the cut-off element
Data Source
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AI summary
A fuel injector for internal combustion engines, comprising: - a valve guide (12) having a longitudinal guide bore (14) and a chamber (16) provided with a valve seat (20), said chamber (26) being connected to a fuel supply duct (18); - an atomizer (26) fixed at a lower end of said valve guide (12), the atomizer (26) having a longitudinal bore (40) in flow connection with said chamber (26) through said valve seat (20), the atomizer having a plurality of nozzle bores (42', 42'') having inner openings (44', 44'') facing into said longitudinal bore (40); and - an axially movable spindle (48) having a valve portion (52) cooperating with said valve seat (20) and a cut-off element (54) extending into said longitudinal bore (40) of the atomizer (26), the cut-off element (54) having a cylindrical sealing portion (56) in sealing contact with a cylindrical sealing surface (58) of said longitudinal bore (40) and a central duct (60) establishing a fluid connection between an upper region (64) and a lower region (70) of said longitudinal bore (40).