Fuel Valve Sealing Liquid System for Low Flashpoint Fuel Leakage
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Solution Overview
Problem
Large low-speed uniflow turbocharged two-stroke internal combustion engines face challenges with low flashpoint fuels due to leakage, mixing with lubrication oil, safety concerns, and poor lubrication properties, leading to reliability issues and the need for dual fuel systems.
Innovation Solution
A fuel valve with an integrated fuel pump and non-return valve design that includes a sealing liquid system and actuation mechanism, allowing for compact and efficient injection of low flashpoint fuels while preventing leakage and enabling easy purging, reducing the complexity of external components and operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If low flashpoint fuel is used in the engine, then cleaner exhaust gas with lower sulfurous components, NOx and CO2 is achieved, but the risk of fuel leakage and mixing with lubrication oil increases due to the low flashpoint
Solution Approach 1:
A sealing liquid system is introduced as an intermediary substance between the fuel and the lubrication oil system. The sealing liquid is supplied under pressure to the clearance between the valve needle shaft and the bore, creating a barrier that prevents low flashpoint fuel from leaking into the lubrication oil system while allowing the engine to operate with clean fuels
2Reliability
If the clearance between the shaft and bore is kept very small to minimize leakage, then fuel leakage is reduced, but lubrication becomes critical and separation of sealing oil and fuel becomes difficult
Solution Approach 1:
The sealing liquid supply system is segmented into multiple injection points along the shaft-bore clearance. By distributing the sealing liquid injection at multiple locations, the system effectively seals the clearance without requiring excessively tight tolerances, and the segmented approach makes it easier to manage the lubrication and sealing functions separately
3Object-affected harmful factors
If low flashpoint fuel remains in the fuel valves and tubing when the engine is not operated on low flashpoint fuel, then safety requirements are violated, but purging the fuel valves and tubing adds operational complexity
Solution Approach 1:
The fuel valve incorporates an automatic purging function that is activated when the engine switches from low flashpoint fuel to fuel oil operation. The purging sequence is initiated automatically before the fuel type change is complete, ensuring that no low flashpoint fuel remains in the fuel valve or tubing when the engine operates on fuel oil, thereby meeting safety requirements without adding manual operational complexity
4Adaptability or versatility
If low flashpoint fuel with poor lubrication properties is used, then fuel injection becomes challenging, but external lubrication systems increase device complexity
Solution Approach 1:
The lubrication function is merged with the sealing liquid supply system. The same sealing liquid that prevents fuel leakage also serves as the lubrication medium for the valve needle shaft and bore. This integration eliminates the need for a separate external lubrication system, reducing device complexity while enabling the engine to operate with low flashpoint fuels that have poor lubrication properties
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 solution effectively manages low flashpoint fuels by minimizing leakage, ensuring safety, and improving reliability by integrating a fuel pump and non-return valve, allowing for efficient and safe operation of low flashpoint fuels in large turbocharged engines.
Implementation Method 1
a non-return valve in the elongated fuel valve housing that prevents flow from the pump chamber to the fuel inlet port
Implementation Method 2
a supply of pressurized sealing liquid 'sealing oil' is applied to the clearance between the shaft and the bore, both for sealing purposes
Implementation Method 3
a pump piston received in a first bore in the valve housing with a pump chamber in the first bore on one side of the pump piston
Implementation Method 4
an actuation liquid port in the fuel valve housing for connection to a source of pressurized actuation fluid
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A fuel valve (50) for injecting low flashpoint liquid fuel into the combustion chamber of a large two-stroke turbocharged self-igniting internal combustion engine. The fuel valve (50) is provided with: an elongated fuel valve housing (52), a nozzle (54) disposed at the front end of the elongated valve housing (52), a fuel inlet port (53), an actuation liquid port (78), an axially displaceable valve needle (61) slidably received in a longitudinal needle bore (64), the valve needle (61) having a closed position and an open position, the valve needle (61) rests on a valve seat (69) in the closed position and the valve needle (61) has lift from the valve seat (69) in the open position and the valve needle (61) being biased towards the closed position, a fuel chamber (58) surrounding the valve needle (61) and opening to the valve seat (69), a pump piston (80) received in a first bore (81) with a pump chamber (82) in the first bore (81) on one side of the pump piston (80), an actuation piston (83) received in a second bore (84) with an actuation chamber (85) in the second bore (84) on one side of the actuation piston (83), the pump piston (80) being connected to the actuation piston (83) to move in unison therewith, the actuation chamber (85) being connected to the actuation liquid port (78), the pump chamber (82) having an outlet connected to the fuel chamber (58) and an inlet connected to the fuel inlet port (53) via a non-return valve (74) in the elongated fuel valve housing (52) that prevents flow from the pump chamber (82) to the fuel inlet port (53). It is suggested that Fig. 7 is published with the abstract