Fuel Injection Pump Barrel Expansion Control Sleeve
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Solution Overview
Problem
Fuel injection pumps in high-pressure applications face radial expansion issues due to thin-walled barrels, leading to increased clearance between the plunger and barrel, causing fuel leakage and reduced volumetric efficiency.
Innovation Solution
The use of one or more sleeves encircling the outer surface of the barrel to apply a load, counteracting radial expansion by selecting materials with higher Young's modulus and controlled thermal expansion, and employing a cooling fluid to regulate temperature and maintain uniform clearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the barrel is designed with thin walls to maintain uniform clearance between plunger and barrel, then thermal mass uniformity is improved, but radial stiffness deteriorates causing radial expansion under high pressure
Solution Approach 1:
The barrel is segmented into multiple sections along its length, with each section having independently controllable wall thickness. This allows thin walls in certain regions to maintain thermal mass uniformity while thicker sections or reinforcement elements provide radial stiffness where needed to prevent expansion under high pressure.
Solution Approach 2:
The barrel employs composite material construction combining materials with different mechanical and thermal properties. This allows the design to achieve both thin wall sections for thermal mass uniformity and regions with enhanced radial stiffness through material selection or composite structuring that resists pressure-induced expansion.
2Productivity
If high pressure is applied to pump fuel, then pumping efficiency is improved, but radial expansion of the barrel increases causing fuel leakage
Solution Approach 1:
The barrel is pre-stressed or pre-loaded during assembly to create initial compressive forces that counteract the radial expansion tendency when high pressure fuel pumping occurs. This preliminary anti-action maintains clearance and prevents fuel leakage even at high operating pressures.
Solution Approach 2:
The barrel's mechanical parameters such as wall thickness distribution, material properties, or structural reinforcement are optimized as functions of the operating pressure range. This allows the barrel to maintain adequate radial stiffness across the full pressure spectrum required for efficient fuel pumping while preventing clearance increase and fuel leakage.
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 effectively reduces radial expansion of the barrel, maintaining uniform clearance, preventing fuel leakage, and enhancing pumping efficiency while prolonging the service life of the fuel system.
Implementation Method 1
employing a cooling fluid to regulate temperature and maintain uniform clearance
Implementation Method 2
one or more sleeves at least partially encircle one or more portions of an outer surface of the barrel and are configured to apply a load to the outer surface of the barrel
Data Source
AI summary
A fuel injection pump is provided. The fuel injection pump includes a barrel including an inner surface defining a bore. The fuel injection pump also includes a plunger movable inside the bore of the barrel. An outer surface of the plunger and the inner surface of the barrel form a clearance therebetween. One or more sleeves at least partially encircle one or more portions of an outer surface of the barrel, and are configured to apply a load to the outer surface of the barrel.