Anti-Reflection Device for Injection Valves
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Solution Overview
Problem
High-pressure injection valves in fuel systems experience pressure waves or pulsations that lead to unstable fuel injection, as the internal pressure conditions are not consistently stable, affecting the control of fuel quantity during valve opening.
Innovation Solution
An anti-reflection device with a cylindrical base body featuring a hollow cone section and sloping through-holes is integrated into the injection valve, creating a low hydraulic impedance to transmit pressure waves while preventing reflections, thereby dissipating energy and minimizing interference with injection events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional injection valve is used, then the valve structure is simple, but pressure waves are reflected inside the valve causing unstable fuel injection
Solution Approach 1:
The anti-reflection device is segmented into distinct functional sections: a first section with a hollow cone cavity and a second section with through-holes. This segmentation allows each section to perform its specific function - the hollow cone prevents pressure wave reflection while the through-holes dissipate energy, thereby resolving the contradiction between maintaining simple valve structure and ensuring stable fuel injection.
Solution Approach 2:
The anti-reflection device acts as an intermediary component inserted into the injection valve. It mediates between the pressure waves generated during injection and the valve system, preventing harmful reflections and dissipating energy to stabilize pressure conditions without fundamentally altering the valve's core injection function.
2Reliability
If pressure waves are transmitted through the valve, then fuel injection control is improved, but pressure wave energy is not dissipated causing continued pulsations
Solution Approach 1:
The second section of the anti-reflection device features through-holes with specific geometric properties (angle α between 40°-60° and diameter 0.2-1 mm) that create localized high impedance zones. These local quality features dissipate pressure wave energy effectively while allowing the overall device to maintain low impedance for pressure wave transmission, thus resolving the contradiction between energy dissipation and pressure stability.
3Ease of manufacture
If the through-holes are arranged parallel to the longitudinal axis, then manufacturing is easier, but energy dissipation of pressure waves is reduced
Solution Approach 1:
The through-holes are deliberately arranged asymmetrically at an angle α between 40°-60° relative to the longitudinal axis rather than parallel to it. This asymmetric arrangement creates more effective energy dissipation pathways for pressure waves while remaining compatible with standard manufacturing processes, resolving the contradiction between manufacturing ease and energy dissipation performance.
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 anti-reflection device effectively transmits pressure waves while preventing reflections, ensuring stable fuel injection by dissipating energy and reducing noise interference, thus enhancing the control over fuel quantity and minimizing undesirable interactions with injection events.
Implementation Method 1
This is due to the low hydraulic impedance of the hollow cone. It ensures that pressure waves are transmitted, but not reflected at the device.
Implementation Method 2
The through-holes help to dissipate energy of the pressure waves.
Implementation Method 3
The anti-reflection device ensures, that pressure waves propagating towards the device from the first base side are transmitted, while pressure waves propagating towards the device from the second base side are reflected due to the high impedance of the at least one through-hole.
Data Source
Figure 1~2
Figure 3
AI summary
An anti-reflection device (1) for preventing the reflection of pressure waves inside an injection valve (23), comprises a base body (3) with a first base side (5), a second base side (7) and an outer surface (9) and a longitudinal axis L to be orientated parallel to a propagation direction of a pressure wave. A first section (11) of the device (1) adjacent to the first base side (5) has a cavity being shaped as a hollow cone (15) and a second section (13) of the device (1) adjacent to the second base side (7) comprises at least one through-hole (21), the at least one through-hole (21) being in fluid communication with the cone (15). The at least one through-hole (21) and the hollow cone (15) hydraulically link the second base side (7) with the first base side (5).