Two-Stage Engine Vibration Filter for Hybrid Gearbox Siren Noise
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Solution Overview
Problem
In hybrid motor vehicles, the transition between thermal and electric power modes leads to new noise issues, particularly high-frequency 'siren noises' from the gearbox, which are not adequately addressed by existing damping solutions.
Innovation Solution
A two-stage vibration filtering device is introduced, comprising an input member on the gearbox, a first elastic body, an output member on the chassis, and a mass interposed between them, allowing for tailored vibration absorption across different frequency ranges, including those generated by the gearbox and engine, using metallic materials for optimal stiffness and space efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a single-stage damping device is used, then the device complexity is low, but it cannot effectively filter high-frequency vibrations from the gearbox in hybrid vehicles
Solution Approach 1:
The damping device is divided into two independent stages: a first damping stage with a first elastic body for low-frequency vibrations, and a second damping stage with a second elastic body for high-frequency vibrations. Each stage targets specific frequency ranges, allowing effective filtering of both low-frequency engine vibrations and high-frequency gearbox siren noises without requiring a single complex device to handle all frequencies.
2Object-affected harmful factors
If a two-stage vibration filtering device is introduced, then vibration absorption across all frequency ranges is improved, but the device complexity increases
Solution Approach 1:
The first and second damping stages are merged into a single integrated damping device assembly. The first elastic body and second elastic body are arranged concentrically around the input shaft, with the second elastic body positioned inside the first elastic body. This merging allows both damping stages to function together in a compact configuration, reducing the overall space required compared to two separate devices while maintaining the ability to filter both low-frequency and high-frequency vibrations effectively.
3Area of stationary object
If the first and second elastic bodies are arranged in a substantially concentric manner, then the device footprint is minimized, but the manufacturing precision requirements increase
Solution Approach 1:
The second elastic body is nested inside the first elastic body in a concentric arrangement around the input shaft. The second elastic body is positioned within the inner cavity of the first elastic body, creating a nested doll-like structure. This nesting configuration minimizes the radial space required for the damping device while maintaining the structural integrity and damping performance of both elastic bodies. The concentric design allows both stages to share the same central axis, reducing the overall footprint without requiring excessive manufacturing precision.
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 device effectively absorbs vibrations across all operating ranges of a hybrid or electric powertrain, reducing noise levels within the vehicle passenger compartment without requiring modifications to the vehicle's geometry, specifically targeting the high-frequency noises associated with electric motor operation.
Implementation Method 1
a first elastic body (113) mounted on this input member (109), a second elastic body (213) mounted on the output member (211)
Implementation Method 2
damping members, commonly called 'Silent Blocks' (registered trademark) or 'dampers' are interposed between the engine of a motor vehicle and its chassis, in order to dampen the vibrations transmitted by this engine to the chassis
Implementation Method 3
a mass (111) interposed between said first elastic body (113) and said second elastic body (213)... said mass is formed in a metal or metallic alloy selected from the group comprising aluminum, steel, cast iron
Data Source
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AI summary
The invention relates to a vibration filtering device for a vehicle engine, comprising: - an input member (109) intended to be fixed on the gearbox of said vehicle, a first elastic body (113) mounted on the input member (109), - an output member (211) intended to be fixed to the chassis of said vehicle, a second elastic body (213) mounted on the output member (211), and - a mass (111) interposed between said first elastic body (113) and said second elastic body (213).