Fuel Injection Valve Sharp-Edged Gap Throttle
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Solution Overview
Problem
Existing fuel injection valves face challenges in achieving precise control over small fuel quantities due to temperature and pressure dependencies, leading to inaccuracies in fuel metering and increased pollutant emissions, particularly in high-pressure systems where low-pressure stages cause leakage and inefficiency.
Innovation Solution
A fuel injection valve design featuring a sharp-edged gap throttle between the valve needle and the pressure chamber wall, independent of the Reynolds number, providing a constant closing force and reproducible fuel injection, regardless of temperature and pressure variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a permanent low-pressure stage is used on the valve needle to provide closing force, then the valve needle closes quickly, but leakage increases and pump efficiency decreases
Solution Approach 1:
The invention extracts the low-pressure stage from the system entirely. Instead of using a permanent low-pressure stage to provide closing force, the patent employs a sharp-edged gap throttle that creates a pressure drop independent of Reynolds number, eliminating the need for a low-pressure stage and its associated leakage problems while maintaining quick valve closure.
Solution Approach 2:
The invention changes the parameter of pressure drop creation from Reynolds-number-dependent (in polished sections) to Reynolds-number-independent (in the sharp-edged gap throttle). This parameter change allows the closing force to remain constant across different fuel temperatures and viscosities, providing reliable quick closure without the inefficiencies of a low-pressure stage.
2Quantity of substance
If polished sections are used to guide fuel past the valve needle, then fuel flow is achieved, but pressure drop and closing force become temperature and pressure dependent
Solution Approach 1:
The invention segments the fuel flow path into two distinct functional zones: polished sections for guiding fuel flow with minimal temperature-dependent effects, and a sharp-edged gap throttle for creating a Reynolds-number-independent pressure drop. This segmentation allows each zone to perform its specific function optimally without the drawbacks of the other.
Solution Approach 2:
The sharp-edged gap throttle acts as an intermediary element that creates a pressure drop independent of fuel viscosity and temperature. This intermediary mechanism decouples the closing force from temperature and pressure variations, ensuring stable and consistent valve needle closure across different operating conditions.
3Quantity of substance
If control valves are made to switch quickly to compensate for weak closing force, then small fuel quantities can be injected, but system complexity and cost increase
Solution Approach 1:
The sharp-edged gap throttle creates a self-regulating closing force that automatically adapts to different operating conditions. The Reynolds-number-independent pressure drop ensures that the closing force remains constant regardless of fuel temperature or viscosity, providing reliable control of small fuel quantities without requiring complex control valves or additional actuators.
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
Ensures quick valve closure and precise control over small fuel quantities, reducing pollutant emissions and system inefficiencies by maintaining a constant throttling effect and closing force, independent of temperature and pressure conditions.
Implementation Method 1
A defined throttle point is created by the fuel injection valve according to the invention, which causes a pressure drop independently of the Reynolds number of the fuel
Implementation Method 2
a sharp-edged gap throttle is formed between the valve needle and the wall of the pressure chamber, which, if suitably dimensioned, causes a pressure drop independently of the Reynolds number of the fuel
Data Source
Figure 1
Figure 2
Figure 3a~3c
AI summary
The invention relates to a fuel injection valve for internal combustion engines, having a valve body (1), in which a pressure chamber (5) is configured, in which a valve needle (3) is disposed in a longitudinally displaceable manner, interacting with a sealing surface (11) having a valve seat (7) configured on the valve needle (3). The valve seat (7) delimits the pressure chamber (5), thus enabling or interrupting a fuel flow to at least one injection opening (8) by means of the interaction of the valve needle (3) with the valve seat (7). To this end, the fuel flow to the injection openings (8) occurs between the valve needle (3) and the wall of the pressure chamber (5), wherein a sharp-edged gap throttle (15) is formed between the valve needle (3) and the wall of the pressure chamber (5).