Wastegate Cup Spring Stack for High-Temperature Durability
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Solution Overview
Problem
Wastegate assemblies in turbochargers face degradation due to high temperatures and corrosive exhaust gas, leading to reduced service life, particularly affecting biasing members like springs.
Innovation Solution
A wastegate assembly design incorporating a plurality of cup springs, where at least two cup springs are oriented identically and stacked, providing thermal protection and increased durability by reducing oxidation and wear, and improving spring coefficient and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single cup spring is used in the wastegate assembly, then the device complexity is reduced, but the service life and reliability are degraded due to oxidation and wear from high temperatures and corrosive exhaust gas
Solution Approach 1:
The single cup spring is segmented into multiple cup springs (at least two) that are disposed in series between the spindle and the valve element. Each cup spring experiences reduced individual stress and oxidation exposure, extending the overall service life of the biasing member while maintaining the functional integrity of the wastegate assembly.
Solution Approach 2:
Multiple cup springs are arranged in series to provide cumulative cushioning and stress distribution before the exhaust gas and thermal environment can cause significant degradation. This pre-distribution of mechanical stress and thermal exposure protects the biasing function from premature failure.
2Duration of action of stationary object
If multiple cup springs are stacked in series, then the service life is improved through reduced oxidation and wear, but the device complexity increases
Solution Approach 1:
The biasing function is segmented into multiple identical or similar cup springs arranged in series. Each spring undergoes the same environmental conditions but shares the mechanical load, reducing individual wear and oxidation rates while maintaining the overall compact structure of the wastegate assembly.
Solution Approach 2:
Multiple cup springs of identical or similar design are used to ensure uniform stress distribution and consistent performance characteristics. This homogeneity simplifies manufacturing and maintenance while maximizing the service life through collective resistance to thermal and chemical degradation.
3Ease of operation
If cup springs are exposed to high temperatures and corrosive exhaust gas, then the wastegate assembly can function, but the spring relaxation and wear increase reducing stability
Solution Approach 1:
Multiple cup springs arranged in series provide cumulative cushioning that absorbs and distributes thermal and mechanical stresses before they can cause significant relaxation or degradation of individual springs. This maintains the stability of the biasing force over extended service life.
Solution Approach 2:
The multiple cup springs are pre-configured to collectively resist the anticipated thermal and chemical degradation from exhaust gas exposure. This preliminary arrangement ensures that the biasing member maintains its mechanical properties and stability throughout the operational lifecycle of the wastegate assembly.
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 dual cup spring configuration enhances the service life of the wastegate assembly by reducing spring relaxation and wear, improving stability, and achieving over 50% better relaxation performance compared to a single cup spring of similar size.
Implementation Method 1
providing thermal protection and increased durability by reducing oxidation and wear
Implementation Method 2
reducing oxidation and wear, and improving spring coefficient and stability
Implementation Method 3
A plurality of cup springs is disposed between the spindle and the washer
Data Source
AI summary
A wastegate assembly for controlling flow of exhaust gas includes a valve element having a valve body and a valve shaft. The wastegate assembly further includes a spindle. The wastegate assembly further includes a washer coupled to the valve shaft and spaced from the spindle for securing the spindle to the valve shaft. A plurality of cup springs is disposed between the spindle and the washer. The plurality of cup springs includes at least a first cup spring and a second cup spring, with the first cup spring supported on the spindle head and the second cup spring orientated substantially identical to the first cup spring and disposed directly on the first cup spring.