Fuel Valve Ignition Liquid Supply for Two-Stroke Engine
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Solution Overview
Problem
Large two-stroke turbocharged compression-ignition internal combustion engines face challenges in reliably igniting difficult-to-ignite fuels like water-oil mixtures, requiring pilot injection of oil or ignition liquids, which leads to technical difficulties in dosage control, increased wear, and safety concerns due to low flashpoint fuels and poor lubrication properties.
Innovation Solution
A fuel valve design that incorporates an ignition liquid supply within the nozzle, allowing ignition to occur internally, reducing the need for external pilot injection, enabling precise control of ignition liquid dosage, and using separate ignition and lubrication systems to manage low flashpoint fuels effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pilot injection of oil or ignition liquid is used to ensure reliable ignition of difficult-to-ignite fuels, then ignition reliability is improved, but dosage control becomes difficult and wear increases
Solution Approach 1:
The patent combines the pilot injection function and main fuel injection function into a single fuel injection valve. The valve needle serves dual purposes: injecting pilot oil/ignition liquid during low-load operation and injecting main fuel during high-load operation, eliminating the need for separate injection systems and simplifying dosage control
Solution Approach 2:
The fuel injection valve is designed to perform multiple functions: it can inject pilot oil, ignition liquid, and main fuel depending on operating conditions. The valve needle and seat assembly can accommodate different injection modes (pilot injection, main injection, or both simultaneously) through a single device, reducing complexity while maintaining reliability
2Quantity of substance
If a full size fuel injection system is used to deliver pilot oil, then the system can handle full load requirements, but precise control of small pilot amounts becomes very difficult
Solution Approach 1:
The valve needle movement is dynamically controlled to achieve different injection quantities. By controlling the timing and duration of valve needle opening, the system can deliver precise small amounts of pilot fuel or larger amounts of main fuel using the same hardware, achieving both full load capacity and precise pilot dosage control
3Measurement precision
If additional small pilot oil injection valves are added, then precise pilot dosage control is achieved, but the top cover becomes even more crowded
Solution Approach 1:
The patent merges the pilot injection valve and main fuel injection valve into a single integrated unit. The valve body houses both pilot oil injection channels and main fuel injection channels, with the valve needle controlling both functions. This eliminates the need for separate pilot injection valves, reducing the number of components in the crowded cylinder head area while maintaining precise dosage control capability
4Object-generated harmful factors
If low flashpoint fuels are used to reduce emissions and costs, then environmental performance is improved, but safety concerns increase due to leakage risks
Solution Approach 1:
The fuel injection valve incorporates self-sealing and self-lubrication features. The valve needle and seat design creates a tight seal that prevents leakage of low flashpoint fuels. The system uses the fuel itself or a small amount of lubricating oil to lubricate moving parts, reducing the need for external lubrication systems that could leak. This self-service approach minimizes leakage risks while enabling the use of environmentally friendly low flashpoint fuels
5Object-generated harmful factors
If water-oil mixtures are used as fuel, then cost and emissions are reduced, but ignition willingness and predictability become problematic
Solution Approach 1:
The system performs preliminary action by injecting pilot oil or ignition liquid before or simultaneously with the main water-oil mixture fuel injection. This preliminary pilot injection creates reliable ignition conditions in advance, ensuring predictable combustion of the difficult-to-ignite water-oil mixture. The pilot injection prepares the combustion chamber by creating a reliable ignition source that will definitely ignite the alternative fuel
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
This solution allows for reliable ignition at low loads below 1% of MCR, reduces ignition liquid consumption, and enhances safety by minimizing leakage and wear, while enabling operation with fuels like diesel oil or DME, and allows for easier purging of low flashpoint fuels.
Implementation Method 1
an axially displaceable valve needle slidably received in a longitudinal needle bore in the elongated valve housing with a clearance between the valve needle and the needle bore, the valve needle having a closed position and an open position, the valve needle rests on a valve seat in the closed position and the valve needle has lift from the valve seat in the open position
Implementation Method 2
a lubricating oil supply conduit connecting the lubricating oil inlet port to the clearance at a first position along the length of the needle bore
Implementation Method 3
an ignition liquid inlet port for connection to a source of pressurized ignition liquid, and an ignition liquid conduit extending from the ignition liquid inlet port to the chamber or to the clearance at a second position along the length of the needle bore
Implementation Method 4
the pump piston being connected to the actuation piston to move in unison therewith, the actuation chamber (85) being connected to an actuation liquid port, the pump chamber having an outlet connected to the fuel chamber and an inlet connected to a fuel inlet port
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A fuel valve (50) for injecting liquid fuel into the combustion chamber of a large slow running two-stroke turbocharged compression-igniting internal combustion engine, comprising an elongated valve housing (52) with a rear end and a front end, a nozzle (54) comprising an elongated nozzle body extending from a base (46) to a closed tip (59), a main bore (55) extending from the base (46) to the closed tip (59) and a plurality of nozzle holes (56) connected to the main bore (55), the nozzle (54) being disposed at the front end of the elongated valve housing (52) with the base (46) connected to the front end, a fuel inlet port (53) in the elongated fuel valve housing (52) for connection to a source (60) of pressurized liquid fuel, an axially displaceable valve needle (61) slidably received in a longitudinal needle bore (64) in the elongated valve housing (52) with a clearance between the valve needle (61) and the 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, the seat (69) being disposed in the elongated valve housing (52) between a fuel chamber (58) in the valve housing (52) and an outlet port (68) in the front end of the elongated valve housing (52), the outlet port (68) connecting directly to the main bore (55) in the nozzle (54), the fuel chamber (58) being connected to the fuel inlet port (53), the clearance opening at one end of the needle bore (64) to the fuel chamber (58), a lubricating oil inlet port (70) for connection to a source of pressurized lubricating oil (57), a lubricating oil supply conduit (47) connecting the lubricating oil inlet port (70) to the clearance at a first position (P1) along the length of the needle bore (64), an ignition liquid inlet port (67) for connection to a source of pressurized ignition liquid (65), and an ignition liquid conduit (66) extending from the ignition liquid inlet port (67) to the chamber (58) or to the clearance at a second position (P2) along the length of the needle bore (64) that is closer to the fuel chamber (58) than the first position (P1).