Engine Mount Bilayer Membrane Eliminates Rattling Noise
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Solution Overview
Problem
Existing engine mounts generate rattling noise due to clearances between the membrane and plate, degrading noise, vibration, and harshness (NVH) performance, particularly during low-frequency vibrations with high amplitude.
Innovation Solution
An engine mount configuration with a bilayer membrane structure, where the upper and lower membranes are attached to a nozzle plate without gaps, allowing fluid flow through orifices and adjusting membrane thickness and inner diameter lengths to tune dynamic characteristics and eliminate rattling noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single membrane is used in the engine mount, then the structure is simple, but rattling noise occurs due to clearances between the membrane and plate during low-frequency vibrations
Solution Approach 1:
The single membrane is divided into two separate membranes (first membrane and second membrane) that are positioned at different locations. The first membrane is attached to the plate while the second membrane is attached to the core, creating a segmented structure that eliminates clearance-related rattling noise by distributing the vibration absorption function across multiple components.
Solution Approach 2:
A fluid chamber filled with fluid acts as an intermediary between the first and second membranes. The fluid transmits vibrations from the core through the second membrane to the first membrane and then to the plate, providing a smooth transmission path that eliminates direct contact and clearance issues between membranes and plates.
2Object-generated harmful factors
If fluid flow path is restricted to reduce rattling noise, then NVH performance improves, but fluid flow resistance increases
Solution Approach 1:
The fluid chamber serves as an intermediary medium that allows fluid to flow between the first and second membranes without requiring direct clearance gaps. This intermediary approach maintains smooth fluid flow paths while eliminating the rattling noise that would occur with clearance-based designs, thus improving NVH performance without significantly increasing flow resistance.
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 bilayer membrane structure eliminates rattling noise, enhances durability, and improves NVH performance by effectively attenuating vibrations across various frequencies, offering increased design freedom for improved vehicle performance.
Implementation Method 1
a fluid encapsulated in the engine mount repeatedly flows upward or downward in the internal space of the engine mount as a main rubber body installed in the engine mount is compressed and restored, to thus attenuate vibrational energy of the engine
Implementation Method 2
the low-frequency vibration with high amplitude or the high-frequency vibration with low amplitude, which occurs when the engine operates, is transmitted to the engine mount, and a fluid encapsulated in the engine mount repeatedly flows upward or downward in the internal space of the engine mount as a main rubber body installed in the engine mount is compressed and restored, to thus attenuate vibrational energy of the engine
Implementation Method 3
the membrane 60 which divides a lower portion below the core 30 and the main rubber body 20 into an upper liquid chamber 11 and a lower liquid chamber 12 in which a liquid is encapsulated
Implementation Method 4
a diaphragm 70 which is made of an elastic material and coupled to a lower portion of the membrane to shield a lower side of the housing 10 of the engine mount
Implementation Method 5
the volume of the upper liquid chamber 11 changes as the core 30 and the main rubber body 20 are deformed in shape, and an amount of fluid that corresponds to the changed volume is delivered from the upper liquid chamber 11 to the lower liquid chamber 12 through an orifice 53 in the plate 50
Implementation Method 6
an amount of fluid that corresponds to the changed volume is delivered from the upper liquid chamber 11 to the lower liquid chamber 12 through an orifice 53 in the plate 50
Data Source
AI summary
An engine mount for a vehicle is provided which attenuates vibration generated when an engine of the vehicle operates. The engine mount includes a main rubber body which supports a core and an inner casing which fixes the main rubber body to a housing. A nozzle plate is mounted in the inner casing and an upper membrane and a lower membrane are attached thereto. The nozzle plate includes a lower plate and an upper plate that is inserted and coupled into the lower plate. The upper membrane is attached to a top plate of the upper plate and the lower membrane is attached to a bottom plate of the lower plate.