Wastegate Device Spring Preload Lever Mechanism

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Solution Overview

Problem

Conventional wastegate devices in exhaust gas turbochargers suffer from angular clearances due to wear, leading to mechanical vibrations and undesirable acoustic noises, and require frequent adjustments to maintain a fluid-tight closure, which is complicated and prone to failure.

Innovation Solution

A lever mechanism with a spring element preload system connects the actuator to the wastegate spindle, ensuring the wastegate flap remains closed even with wear, providing a failsafe function in case of actuator failure by exerting additional pressure to maintain a fluid-tight seal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If conventional wastegate devices are used without compensation mechanisms, then the structure is simple, but angular clearances develop due to wear leading to mechanical vibrations and acoustic noises

Engineering Contradiction:
Improvewastegate device structureVSAvoidflap mechanism reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

A spring element is integrated into the lever mechanism to pre-load the wastegate flap against the closed position. This spring element compensates for angular clearances and wear in the flap mechanism beforehand, preventing mechanical vibrations and acoustic noises without requiring complex compensation mechanisms.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Manufacturing precision

If angular clearances are provided to compensate for wear, then the initial positioning is improved, but wear in the components increases over time

Engineering Contradiction:
Improveflap mechanism positioningVSAvoidcomponent wear resistance
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The spring element dynamically adjusts the preload force on the wastegate flap, compensating for wear and angular clearances through elastic deformation rather than relying on fixed angular clearances in the mechanical joints. This reduces wear in the flap mechanism components.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If frequent adjustments are made to maintain fluid-tight closure, then the sealing performance is improved, but the maintenance complexity and failure risk increase

Engineering Contradiction:
Improvewastegate closure sealingVSAvoidadjustment mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The spring element automatically compensates for wear and maintains the fluid-tight closure of the wastegate flap without requiring manual adjustments. The spring continuously applies preload force to ensure sealing performance, eliminating the need for complex adjustment mechanisms and reducing maintenance requirements.

Inventive Principle:
Principle #25Self-service

4Device complexity

If no failsafe mechanism is provided, then the device complexity is reduced, but the system fails to maintain closure upon actuator failure

Engineering Contradiction:
Improvefailsafe mechanism complexityVSAvoidactuator failure resistance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The spring element is pre-loaded to exert a closing force on the wastegate flap that opposes the opening force from exhaust gas pressure. In the event of actuator failure, this pre-loaded spring automatically maintains the wastegate flap in the closed position, providing a failsafe function without requiring additional complex mechanisms.

Inventive Principle:
Principle #9Preliminary anti-action

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 effectively mitigates wear-related issues and ensures a fluid-tight closure of the wastegate opening, reducing acoustic noise and preventing exhaust gas leakage, even if the actuator fails, through a simple and reliable drive coupling mechanism.

Implementation Method 1

a spring element (16), which preloads the wastegate flap (4) against the closed position, in which it closes the wastegate opening (19)

Methodology Applied
Scientific EffectSpring element preload: Spring

Implementation Method 2

The preload force generated by the spring element (16) and acting on the first lever arm (8) allows it to omit a tracking of the closed position of the wastegate valve (4)

Methodology Applied
Scientific EffectSpring force: Spring

Data Source

PatentEP2821615B1Wastegate device for an exhaust gas turbocharger
Publication Date: 2016.05.18 BOSCH MAHLE TURBO SYST GMBH & CO KG
  • EP2821615B1 patent drawingFigure 1a~1c

AI summary

The invention relates to a wastegate device (1) for an exhaust gas turbocharger, - with a housing (2), in which a wastegate opening for the flowing-through of an exhaust gas is provided, - with a spindle (3) which is rotatably mounted on the housing (2), on which a wastegate flap (4) is arranged, which by turning the spindle (3) can be adjusted between an opened position, in which it opens the wastegate opening for the through-flow of exhaust gas and a closed position, in which it closes the wastegate opening, - with an actuator device (5) which is drive-connected to the spindle (3) for adjusting the wastegate flap (4) by means of a lever mechanism (7), - wherein the lever mechanism (7) comprises at least one first and one second lever arm (8, 9), which are interconnected in an articulated manner by means of a first joint arrangement (11), - wherein on the first joint arrangement (11) a spring element (16) is provided, which preloads the wastegate flap (4) against the closed position via the lever mechanism (7).