Vehicle Exhaust Mounting Isolators for Mass Reduction
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Solution Overview
Problem
Existing vehicle exhaust systems are heavy due to the need for thick materials to withstand mechanical loads and stringent emissions requirements, while also needing to reduce acoustic outputs, leading to complex designs that increase mass.
Innovation Solution
A vehicle exhaust assembly with an exhaust mounting assembly that includes first and second isolator devices to resiliently constrain movement of the intermediate and outlet sections, reducing mechanical loads and allowing for thinner materials, and exhaust decouplers to reduce vibration transmission, thereby minimizing the overall mass of the exhaust system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If stainless steel with gauge thickness of 1.2mm or 1.5mm is used for the exhaust system, then the mechanical strength and durability are sufficient to withstand mechanical loads, but the mass of the exhaust system becomes significant
Solution Approach 1:
The exhaust system is divided into separate sections (inlet section, intermediate section, outlet section) that are decoupled from each other. This segmentation allows each section to be independently supported by isolator devices, reducing the need for continuous thick-walled construction throughout the entire system and enabling mass reduction while maintaining local strength requirements.
Solution Approach 2:
Isolator devices are introduced as intermediary elements between the exhaust system sections and the vehicle body. These isolators absorb and distribute mechanical loads, reducing the stress on the exhaust system walls and enabling the use of thinner gauge materials while maintaining adequate strength and durability.
2Reliability
If larger and more complex after-treatment devices are used to meet emissions legislation, then emissions control effectiveness is improved, but the mass and complexity of the exhaust system increase
Solution Approach 1:
The exhaust system is segmented into inlet, intermediate, and outlet sections with decouplers between them. This segmentation allows after-treatment devices to be positioned and supported independently, optimizing their placement for emissions control while the isolator devices bear the mechanical loads, enabling thinner wall construction elsewhere in the system.
Solution Approach 2:
Isolator devices serve as intermediaries that support the weight and mechanical loads of larger after-treatment devices, freeing these components from needing self-reinforcing thick walls. This allows after-treatment devices to be optimized for emissions performance without contributing excessive mass to the overall exhaust system.
3Object-affected harmful factors
If additional structural vibration palliatives are added to reduce vibrations, then vibration control is improved, but the device complexity and mass increase
Solution Approach 1:
The isolator devices perform multiple functions simultaneously: they support the exhaust system sections, reduce mechanical loads on the system, and provide vibration isolation. By merging these functions into a single component, the need for separate vibration palliatives is eliminated, reducing overall system complexity while maintaining effective vibration control.
Solution Approach 2:
The isolator devices are designed as multi-functional components that provide mechanical support, load reduction, and vibration isolation in a single element. This universal approach replaces what would traditionally require multiple separate components (supports, braces, and vibration dampers), reducing both mass and complexity while addressing all three requirements.
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 reduces the mechanical loads on the exhaust system, allowing for a significant mass reduction of approximately 50% and eliminates the need for additional structural vibration palliatives, while maintaining effective noise reduction and emissions control.
Implementation Method 1
one or more first isolator device for resiliently constraining movement of the intermediate section of the exhaust system
Implementation Method 2
one or more exhaust decoupler for decoupling the intermediate section from the inlet section
Data Source
Figure 1
Figure 2A~2D
Figure 3
AI summary
The present disclosure relates to a vehicle exhaust assembly (1) for an internal combustion engine. The vehicle exhaust assembly (1) comprises an exhaust system (3) and an exhaust mounting assembly (4) for mounting the exhaust system (3) to a vehicle (2). The exhaust system (3) comprises an inlet section (5) for connection to the internal combustion engine; an intermediate section (6) connected to the inlet section (5); an outlet section (7) for exhausting gases from the internal combustion engine; and one or more exhaust decoupler (8) for decoupling the intermediate section (6) from the inlet section (5). The exhaust mounting assembly (4) comprises one or more first isolator device (20-1, 20-2) for resiliently constraining movement of the intermediate section (6) of the exhaust system (3) in a longitudinal direction; and one or more second isolator device (20-3, 20-4) for resiliently constraining movement of the outlet section (7) of the vehicle (2) exhaust in a transverse direction. The present disclosure also relates to a vehicle (2) including a vehicle exhaust assembly (1).