Patent Application
20060201470
The present invention relates to a reciprocating internal combustion engine component that has a honeycomb structure.
It is highly desirable to reduce the noise and vibration generated by a motor vehicle, in particular by a passenger car. In a motor vehicle with an internal combustion engine, the engine system, including the reciprocating internal combustion engine and its accessory parts, is a major source of vibration and noise. A portion of the noise and vibration generated by the reciprocating internal combustion engine system is transmitted through the components of the engine system to the ambient environment and to the other components of the vehicle. The rest of the generated noise and vibration is absorbed by the components of the engine system.
It has been known in the past to wrap some jet aircraft engine components in with a covering having a cellular structure to reduce noise. Such coverings, however, have not been considered applicable to reciprocating internal combustion engines of motor vehicles.
How much of the generated noise and vibration is transmitted (or absorbed) by a component of the engine system depends to a large extent on the material and configuration of the component. Applicant noticed that a thin plate-like component, such as a cover or a thin wall of an engine manifold, cannot absorb much vibration and noise. Applicant also noticed that, since a thin plate-like component generally does not have much damping and its natural frequencies are within the frequency range of the generated vibration and noise, it can be easily excited at its natural frequencies. As a result, the noise and vibration is actually amplified by the component.
Applicant discovered that when a thin plate-like component of an engine system is reinforced with a honeycomb structure, the amount of vibration and noise transmitted through the component can be significantly reduced. In particular, the air trapped in the honeycomb structure functions as a noise insulator, resulting in a significant reduction in the amount of noise transmitted through the component. Additionally, the component can no longer be excited at its natural frequencies to amplify the vibration and noise because its natural frequencies have been moved outside of the frequency range of the generated vibration and noise. Further, the stiffness of the component can be increased without a corresponding increase in material or weight. The term “honeycomb structure” is a known and well-understood term in structural engineering which refers to a structure formed with hollow, thin-walled cells or cavities, especially hexagonal cells. The cells or cavities of the honeycomb structure of the invention are preferably generally hexagonal, but need not be strictly so, and other hollow cellular configurations can be envisioned within the scope of the invention, e.g., diamond-shaped cells.
According to one aspect of the invention, a component of an reciprocating internal combustion engine system includes two layers and a honeycomb layer disposed between the two layers. Preferably, the component of the engine system has a thin plate-like configuration, and the two layers are attached to the honeycomb structure with adhesive or with fasteners, or are welded to the honeycomb structure. The component of the engine system may be a manifold, such as an intake manifold, or a wall of a manifold. The component may also be a cover, such as an acoustic cover or a valve cover.
The invention will be described in further detail hereinafter with reference to illustrative preferred embodiments shown in the accompanying drawing figures in which:
Although the wall 12 of the manifold 10 shown in
The honeycomb layer 18 preferably is attached to the inner and outer layers 14, 16 and may be attached to the inner and outer layers 14, 16 in any suitable manner. For example, the honeycomb layer 18 may be glued, fastened, or welded to and between the inner and outer layers 14, 16.
A particularly preferred technique for attaching the first and second or outer layers to the third or inner layer is overmolding in which the first and second layers are formed of, for example, synthetic resin material by molding them around a core of honeycomb material. It is especially preferred to use a two-stage molding technique in which the honeycomb core is formed in a first stage and then the outer layers are formed in a second stage by molding them around the core.
The component may have the three-layer structure at any portion of the component where it may be used to reduce vibration and noise. In the embodiment shown in
The honeycomb layer 118 preferably is attached to the inner and outer layers 114, 116 and may be attached to the inner and outer layers 114, 116 in any suitable manner. For example, the honeycomb layer 118 may be glued, fastened, or welded to and between the inner and outer layers 114, 116.
The cover 110 may have the three-layer structure at any portion of the cover where it may be used to reduce vibration and noise. For example, the entire cover may be made from the three-layer structure, or only a portion of the cover may be made from the three-layer structure.
Although the components illustrated in
The foregoing description and examples have been set forth merely to illustrate the invention and are not intended to be limiting. Since modifications of the described embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed broadly to include all variations within the scope of the appended claims and equivalents thereof.
| Number | Date | Country | |
|---|---|---|---|
| 60660097 | Mar 2005 | US |
