Tapered Fuel Injector Insert for Cylinder Head
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Solution Overview
Problem
In direct fuel injection internal combustion engines, the injector nozzle often becomes tightly wedged in the cylinder head, requiring excessive force for removal, which can result in damage to the nozzle, sealing ring, or cylinder head, due to material transfer from cast aluminum heads.
Innovation Solution
A tubular insert with a tapered passageway is used within the cylinder head bore to receive the fuel injector nozzle, preventing bonding and reducing frictional contact, allowing for easier removal and minimizing damage, constructed from materials like 7075 aircraft grade aluminum to match thermal expansion properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the injector nozzle is directly sealed within the cylinder head bore, then sealing performance is improved, but removal difficulty increases and damage risk worsens
Solution Approach 1:
The system is divided into three segments: the cylinder head bore, the removable insert, and the injector nozzle. The insert acts as an intermediate component that can be independently removed, allowing the nozzle to be accessed without damaging the cylinder head. This segmentation resolves the contradiction by maintaining the seal during operation while enabling easy removal during maintenance.
Solution Approach 2:
The insert serves as an intermediary component between the cylinder head bore and the injector nozzle. It provides the sealing function during operation but can be removed to access the nozzle for cleaning or replacement. This intermediary element resolves the contradiction by decoupling the sealing requirement from the removal difficulty.
2Reliability
If the injector nozzle is tightly wedged in the bore, then sealing performance is improved, but material transfer and damage increase
Solution Approach 1:
By segmenting the sealing interface into two locations (bore-to-insert and insert-to-nozzle), the harmful material transfer is prevented. The insert is designed with clearance fits that allow thermal expansion without bonding, eliminating the galvanic corrosion and material transfer issues that occur with tight interference fits in aluminum cylinder heads.
Solution Approach 2:
The insert acts as a protective intermediary between the aluminum cylinder head and the injector nozzle. It prevents direct contact and material transfer between these components while maintaining the necessary sealing function, thereby eliminating the harmful effects of thermal expansion mismatch and galvanic corrosion.
3Productivity
If excessive force is applied to remove the injector, then removal is achieved, but damage to the nozzle, sealing ring, or cylinder head occurs
Solution Approach 1:
The removable insert segment allows the injector nozzle to be accessed and removed without applying excessive force to the cylinder head bore. The insert can be independently removed to access the nozzle, protecting the nozzle, sealing ring, and cylinder head from damage during maintenance operations.
Solution Approach 2:
The insert serves as a removable intermediary that protects the injector nozzle and cylinder head bore from damage during removal operations. By removing the insert first, the nozzle can be accessed without applying excessive force that would damage the expensive aluminum cylinder head or the precision nozzle components.
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 insert facilitates simpler removal and maintenance of fuel injectors by reducing the force required and preventing material transfer, thus minimizing damage to the nozzle and cylinder head.
Implementation Method 1
A tubular insert with a tapered passageway is used within the cylinder head bore to receive the fuel injector nozzle, preventing bonding and reducing frictional contact
Implementation Method 2
constructed from materials like 7075 aircraft grade aluminum to match thermal expansion properties
Data Source
AI summary
An insert for a cylinder head of an internal combustion engine that has a bore for receiving a fuel injector to deliver fuel through an injector nozzle into a combustion chamber. The insert comprises a generally tubular body having a longitudinally oriented passageway therethrough and receivable within the bore in the cylinder head. The generally tubular body has an inner end and an outer end, with the inner end in proximity to the combustion chamber when said insert is received within the bore. The passageway is tapered such that its diameter increases from the inner end toward the outer end. The longitudinal passageway is dimensioned to sealingly receive the nozzle of the fuel injector when the fuel injector is received within the bore. The insert limits blow-by between the insert and the nozzle of the fuel injector during operation of the internal combustion engine.