Dynamic Liner Sleeve for Diesel Exhaust Flexible Coupling
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Solution Overview
Problem
Flexible couplings in diesel engine exhaust systems experience high failure rates due to severe NVH environments and inefficient exhaust gas temperature retention, leading to reduced performance of after-treatment devices like DPF and SCR, which are critical for meeting emission standards.
Innovation Solution
A continuous, axial spiral-pattern wound sleeve is interposed between the bellow and liner in the coupling, allowing dynamic movement in 6 degrees of freedom, preventing direct contact, reducing thermal heat loss, and damping vibrations to enhance durability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a static spacer is used between bellow and liner, then thermal loss is reduced, but the coupling cannot accommodate dynamic movement and stress-induced configuration changes
Solution Approach 1:
The patent replaces static spacers with a dynamic resilient material that can accommodate movement and configuration changes while maintaining thermal insulation. The resilient material deforms elastically to allow the coupling to expand, contract, and flex dynamically, preventing liner-to-bellow contact during operation while preserving thermal barrier properties.
Solution Approach 2:
The patent uses a composite structure combining a thermal barrier coating on the liner with a resilient interstitial material. This composite approach provides both thermal insulation and mechanical compliance, allowing the system to handle dynamic stresses while reducing heat loss to the bellow.
2Device complexity
If the bellow and liner are directly connected, then structural simplicity is achieved, but thermal heat loss increases and liner-to-bellow contact causes wear and failure
Solution Approach 1:
The patent introduces a resilient interstitial material as an intermediary between the liner and bellow. This intermediate layer prevents direct contact between the liner and bellow, eliminating wear and thermal conduction pathways, while still allowing the coupling to function as a unified flexible element.
Solution Approach 2:
The resilient interstitial material acts as a flexible protective layer that conforms to the dynamic shape changes of the coupling. This thin film or coating provides continuous protection against liner-to-bellow contact while maintaining the flexibility needed for exhaust system dynamics.
3Loss of energy
If a rigid thermal barrier is used between liner and bellow, then thermal insulation is improved, but the coupling's flexibility and vibration damping capability are reduced
Solution Approach 1:
The patent changes the physical parameters of the thermal barrier by using a resilient material with viscoelastic properties instead of a rigid insulator. This material provides thermal insulation while simultaneously offering vibration damping and flexibility, optimizing both thermal management and mechanical performance.
Solution Approach 2:
The resilient interstitial material functions as a flexible thermal barrier that maintains insulation properties while accommodating the dynamic deformation of the coupling. This flexible film or coating allows the system to absorb vibrations and maintain flexibility during operation.
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 solution significantly reduces NVH, increases bellow fatigue durability, maintains exhaust gas temperature, and enhances the efficiency of after-treatment devices by preventing liner-to-bellow contact and heat conduction, thereby improving the overall performance of the exhaust system.
Implementation Method 1
The sleeve also dampens natural vibration or frequencies of the bellow thus reduces NVH and increases bellow fatigue durability. Most importantly, it also prevents bellow to liner contact abrasion in harsh NVH environments (when high g-loads are applied to the flexible coupling).
Implementation Method 2
The sleeve also dampens natural vibration or frequencies of the bellow thus reduces NVH and increases bellow fatigue durability.
Implementation Method 3
Most importantly, it also prevents bellow to liner contact abrasion in harsh NVH environments (when high g-loads are applied to the flexible coupling).
Data Source
AI summary
A flexible coupling includes a liner, a bellow, and a liner sleeve preferably defined by a compressed woven mesh strip spirally wound around the liner between the bellow and liner and moveable longitudinally with respect to the bellow and liner when the coupling expands linearly. An alternate sleeve in the form of a cylinder is disposed about the liner, under the bellow and is formed of a woven non-compressed mesh.