Fuel Booster Unit Sealing Structure for High-Pressure Leakage Control
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Solution Overview
Problem
Existing fuel booster units for large engines face reliability and operational safety issues due to unintended fuel leakage when pressurizing fuels like methanol from low to high pressure, particularly when operating with renewable fuels.
Innovation Solution
A fuel booster unit design featuring a plunger and hydraulic piston configuration with a low pressure fuel groove and fuel return line to recycle leaked fuel, along with a sealing fluid system to maintain pressure differential and prevent leakage, enhancing operational safety and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a fuel booster unit pressurizes fuel from low pressure to high pressure using a plunger and hydraulic piston, then the fuel injection pressure is improved, but fuel leakage occurs between the plunger and plunger cylinder
Solution Approach 1:
The plunger rod is divided into multiple sealed sections (first sealed section, second sealed section, third sealed section) with separate sealing arrangements. Each section has its own packing gland and sealing mechanism, allowing independent sealing control. This segmentation prevents leakage by creating multiple barriers rather than relying on a single sealing interface.
Solution Approach 2:
A bridging component (verbindungselement) connects the first and second plunger rods, acting as an intermediary element that transmits force while maintaining sealing integrity. This intermediate component allows the system to accommodate thermal expansion and manufacturing tolerances while preventing fuel leakage between sections.
2Reliability
If sealing fluid is supplied at high pressure to prevent fuel leakage, then sealing effectiveness is improved, but the complexity of the pressure control system increases
Solution Approach 1:
The sealing system uses self-regulating mechanisms where the sealing fluid pressure automatically balances with the fuel pressure through the packing glands. The system maintains sealing effectiveness through inherent pressure equilibrium rather than requiring complex external pressure control, reducing system complexity while ensuring reliable sealing.
3Stability of the object's composition
If the plunger rod is made long to accommodate thermal expansion, then thermal stability is improved, but the risk of fuel leakage increases
Solution Approach 1:
The plunger rod is segmented into multiple sections with intermediate bridging components. Each section can expand thermally independently within its sealed compartment, accommodating thermal expansion while maintaining sealing integrity. The segmentation prevents a single long rod from becoming a leakage risk while preserving thermal stability.
Solution Approach 2:
The sealing system incorporates pre-positioned packing glands and sealing elements that anticipate thermal expansion movements. These sealing arrangements are designed to accommodate expected thermal movements before they occur, maintaining sealing effectiveness throughout the full range of thermal expansion without creating leakage paths.
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 design effectively reduces fuel leakage and ensures reliable operation by recycling leaked fuel and maintaining a controlled pressure differential, improving safety and efficiency in fuel pressurization for large engines.
Implementation Method 1
a hydraulic piston (3) extending in and movable back and forth in the axial direction in a hydraulic cylinder (35), wherein the hydraulic piston (3) comprises a low pressure end (31) for actuating the plunger (2), and a piston connection end (33) for establishing the plunger-piston-connection
Implementation Method 2
an actuating port (7) for supplying an actuating fluid to the low pressure end (31) of the hydraulic piston (3) for actuating the hydraulic piston (3) and, by means of the plunger-piston-connection, the plunger (2)
Data Source
Figure 1
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AI summary
A fuel booster unit is proposed for pressurizing a fuel for a large engine (100) from a low pressure to a high pressure, the fuel booster unit comprising - a pressure chamber (4) for the fuel, a fuel inlet (5) for supplying the fuel at the low pressure to the pressure chamber (4), a fuel outlet (6) for discharging the fuel at the high pressure from the pressure chamber (4), - a plunger (2) movable back and forth in an axial direction (A) in a plunger cylinder (25), wherein the plunger (2) comprises a high pressure end (22) which at least partially delimits the pressure chamber (4), and wherein the plunger (2) comprises a plunger connection end (23) for establishing a plunger-piston-connection, - a hydraulic piston (3) extending in and movable back and forth in the axial direction (A) in a hydraulic cylinder (35), wherein the hydraulic piston (3) comprises a low pressure end (31) for actuating the plunger (2), and a piston connection end (33) for establishing the plunger-piston-connection, - an actuating port (7) for supplying an actuating fluid to the low pressure end (31) of the hydraulic piston (3) and the plunger (2). The plunger cylinder (25) comprises a low pressure fuel groove (8) arranged between the high pressure end (22) and the plunger connection end (23), wherein the low pressure fuel groove (8) is configured to collect fuel residues leaking from the pressure chamber (4) between the plunger (2) and the plunger cylinder (25), and the fuel booster unit comprises a fuel return line (81) configured to connect the low pressure fuel groove (8) with the fuel inlet (5) for guiding at least a part of the fuel residues back to the fuel inlet (5). Furthermore, a large engine comprising such a fuel booster unit is proposed.