Deformable Plunger Sleeve for High-Pressure Pump Volumetric Efficiency
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Solution Overview
Problem
High-pressure fuel in high-pressure pumps tends to return to low-pressure areas through plunger clearances, reducing volumetric efficiency, especially at low rev conditions, leading to increased weight and cost or accelerated wear when attempting to compensate.
Innovation Solution
The high-pressure pump design includes a plunger sleeve with a first and second section, where the protruding member divides the pressure chamber, allowing the first section to deform inward during fuel pumping, reducing clearance, and recover during fuel sucking, maintaining efficient operation without increasing weight or using expensive materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the machining clearance in the plunger set is reduced to counteract backflow, then volumetric efficiency is improved, but wear resistance decreases and service life is reduced
Solution Approach 1:
The plunger sleeve is designed with a deformable structure that dynamically adjusts the clearance between the plunger and plunger sleeve based on operating conditions. During the fuel pumping stage, the plunger sleeve deforms to reduce clearance and minimize backflow, while during the fuel suction stage, the clearance increases to reduce wear. This dynamic adjustment resolves the contradiction between maintaining high volumetric efficiency and ensuring long service life.
2Productivity
If a larger fuel pumping volume is selected to compensate for decreased volumetric efficiency, then fuel supply capacity is maintained, but weight increases
Solution Approach 1:
The invention changes the physical state and dimensions of the plunger sleeve through controlled deformation. By adjusting the clearance parameter dynamically between pumping and suction stages, the system maintains high volumetric efficiency without requiring increased pump volume, thereby avoiding weight increase while preserving fuel supply capacity.
3Productivity
If the length of the plunger clearance is increased to counteract backflow influence, then volumetric efficiency is improved, but device complexity and cost increase
Solution Approach 1:
The plunger sleeve is designed as a flexible, deformable component that can dynamically change its internal dimensions. This flexible structure allows the sleeve to contract during the pumping stage to reduce clearance and minimize backflow, eliminating the need for longer rigid clearances or additional sealing components, thereby maintaining simplicity while improving volumetric efficiency.
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 design enhances volumetric efficiency, reduces wear, and extends service life by minimizing machining clearance, while accommodating higher fuel pressures without increased weight or material costs, improving fuel combustion and reducing consumption.
Implementation Method 1
In the fuel pumping stage, the first section is deformed and shrunk inwards due to the pressure difference between the inside and the outside of the first section
Implementation Method 2
the first section of the plunger sleeve deforms to contract inwards
Implementation Method 3
In the fuel sucking stage, no pressure difference generated between the inside and the outside of the first section, so that the first section is recovered from the contracted configuration to the shape before deformation
Data Source
Figure 1~2
Figure 3~4
Figure 5a~5d
AI summary
A high-pressure pump, comprising: a pressure chamber, a plunger sleeve (3) disposed in the pressure chamber, and a protruding member (8) disposed at an outer side of the plunger sleeve (3) and in interference fit to the wall of the pressure chamber. The plunger sleeve (3) comprises a first section (31) and a second section (32) connected to the first section (31). The protruding member (8) is disposed on an outer side of the second section (32) close to the first section (31). The protruding member (8) divides the pressure chamber into a first pressure chamber (1) and a second pressure chamber (2), and the first section (31) is located in the first pressure chamber (1). By lowering the protruding member (8), under the premise of the same volumetric efficiency, the high-pressure pump has a larger plunger clearance in the oil sucking stage, less wear to the plunger set, and a longer service life.