Fuel Injection Device Spool Linear Contact Sealing
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Solution Overview
Problem
Fuel injection systems in diesel engines suffer from fuel leakage from the pressure control chamber, leading to inefficiencies in fuel injection and increased energy consumption.
Innovation Solution
A fuel injection device with a spool and depressurization flow passage formation member, featuring a protruding part with a linear contact portion that reduces fuel leakage by closing the depressurization flow passage opening when the piston surface moves, improving injection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the depressurization flow passage is opened to enable fuel injection, then fuel can be injected from the fuel injection hole, but fuel leaks from the pressure control chamber through the depressurization flow passage
Solution Approach 1:
The protruding part with linear contact portion is positioned in advance to close the depressurization flow passage opening when the piston surface moves, preventing fuel leakage before it can occur during the injection cycle
Solution Approach 2:
The linear contact portion is specifically formed on the protruding part of the piston surface to create a localized sealing interface with the inclined surface, providing targeted sealing at the critical leakage point without affecting other components
2Reliability
If fuel leaks from the pressure control chamber, then the depressurization flow passage functions to open the pressure control chamber, but injection efficiency decreases due to fuel loss
Solution Approach 1:
The sealing mechanism uses the dynamic movement of the piston surface, where the protruding part automatically contacts the inclined surface during piston movement to close the depressurization flow passage, making the sealing action dynamic rather than static
Solution Approach 2:
The linear contact portion maintains continuous sealing contact with the inclined surface during the piston movement, ensuring uninterrupted prevention of fuel leakage throughout the injection cycle
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 device significantly reduces fuel leakage from the pressure control chamber, enhancing injection efficiency and reducing energy consumption.
Implementation Method 1
a solenoid actuator 40... movable along an axial direction of the casing (12) by operation of the solenoid actuator (40)
Implementation Method 2
the protruding part (51) has a linear contact portion (Lc) that comes into linear contact with the inclined surface (50b) and is capable of closing the opening (26b) when the piston surface (24a) is moved to the other end side
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
One embodiment of a fuel injection device according to the present disclosure is provided with: a casing in which a fuel injection hole is formed at the leading end thereof and a fuel passage is formed thereinside; a spool including a needle valve that is disposed so as to be movable along the axial direction of the casing by the operation of an electromagnetic actuator and that is capable of opening and closing the fuel injection hole, and a drive piston that faces a pressure control chamber in communication with the fuel passage; and a pressure reduction flow passage formation member having formed therein a pressure reduction flow passage that has an opening formed in a facing surface facing a piston surface and an outlet port to be opened and closed by the operation of the electromagnetic actuator, and that is in communication with the pressure control chamber. The piston surface has a protruding part that protrudes to the opening side, and the pressure reduction flow passage formation member has an inclined surface that is inclined so as to have a diameter which decreases from the opening along a direction away from the piston surface. The protruding part has a linear contact portion capable of linearly contacting with the inclined surface and closing the opening when the piston surface moves to the other end side.