Water Injection Filter Venting to Prevent Pump Cavitation
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Solution Overview
Problem
Existing water injection systems for internal combustion engines face challenges such as bulkiness of filtration devices, instability of filter media near pump suction paths, air bubble formation causing cavitation, and the need for frequent pump bleeding due to temperature variations, which degrade water injection efficiency and require complex pump dismantling.
Innovation Solution
A compact filtration device integrated into the water distribution line, featuring a non-return valve, degassing vents, and a fabric permeable to liquid water to prevent air bubbles, allowing for efficient priming and purging without air pockets, and a design that enables direct immersion in the water tank for effective filtration close to the suction path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a filter medium is placed near the pump suction inlet, then filtration is achieved, but treatment stability issues occur and the pump cannot properly draw water from a sufficiently low level
Solution Approach 1:
The filter medium is arranged vertically suspended in the water tank rather than horizontally at the suction inlet. This vertical arrangement allows the pump to draw water from lower levels while the filter medium remains suspended above, resolving the contradiction between filtration effectiveness and water suction capability from low levels.
2Reliability
If a pump and filter media are used to distribute clean water, then water filtration is achieved, but excessive space is required
Solution Approach 1:
The filter medium is integrated directly into the water tank structure, eliminating the need for a separate filter housing. The pump and filter media share the same space within the water tank, significantly reducing the overall volume required for the water distribution system.
Solution Approach 2:
The water tank serves multiple functions: it stores water, supports the filter medium, and acts as the filtration chamber. This multi-functionality eliminates the need for separate dedicated filter housing, reducing the total space required for the system.
3Reliability
If air bubbles form in the water circuit downstream of filtration and upstream of the pump, then cavitation occurs, but the water injection control is degraded
Solution Approach 1:
Air bubbles are extracted from the water circuit through a dedicated air vent positioned at the highest point of the filter medium. This vent allows air to escape during the filtration process, preventing bubble accumulation that would cause cavitation and degrade water injection control.
Solution Approach 2:
Air is removed from the water circuit during the priming phase before the pump begins operation. The air vent is designed to automatically release trapped air during filling and priming, ensuring that only bubble-free water enters the pump and injection system.
4Adaptability or versatility
If the pump is purged frequently due to temperature variations causing water freezing, then the system can operate in cold conditions, but complex pump dismantling is required
Solution Approach 1:
The system performs self-purging through the air vent mechanism. During cold conditions, air trapped in the system expands and automatically escapes through the vent, eliminating the need for manual pump dismantling and complex purging procedures. The air vent serves as a self-service mechanism for handling temperature-related issues.
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 filtration device ensures stable and efficient water filtration, minimizing air bubbles and cavitation, allowing for continuous operation without complex pump dismantling, and optimizing compactness and longevity of the filtration system.
Implementation Method 1
a filter medium (5) surrounded by an external component (2) extending into a filtration region (RF) below an upper end (2b) of the external component (2)
Implementation Method 2
a non-return valve mounted on the external component (2) and provided in a barrier portion including the upper end (2b) and a side wall (2c) of the external component (2), the valve allowing a degassing path to be formed when air flows upwards along the dam part in the filtration region (RF) or is pressurized in the filtration region
Implementation Method 3
a fabric permeable to liquid water to prevent air bubbles
Data Source
Figure 1
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Figure 3
AI summary
The filtration device (1), integrated into a water intake module with adjacent compartments for a pump and the device, purifies water intended for a vehicle's combustion chamber. The device comprises, within an outer casing (2) equipped with an outlet (6), a filter medium (5) interposed between an inlet (4) and the outlet (6), and a degassing valve (CV). The outer casing has a dammed portion (16) beneath which the inlet (4) is formed. A vent (O) formed in this portion (16) is closed by default by a valve flap. When the valve flap is subjected to overpressure on the side of a filtration region, it shifts to release the vent, which then defines an access point between the filtration region and an external zone without passing through the inlet (4). The vent (O) allows degassing when the pump is purged.