DESC:FIELD OF INVENTION

The present invention relates to reducing the overall noise and vibration (NVH) levels in vehicle substructure. In particular, the invention relates to configuring a light-weight vehicle substructure for improving NVH performance. More particularly, the present invention relates to enhancing the in-cab noise quality in a running automotive vehicle.

BACKGROUND OF THE INVENTION

Today, the automotive customers are demanding ever more quiet and comfortable vehicles. However, meeting expected NVH performance and keeping the vehicle weight low often poses a challenge to the automotive designers. Moreover, vast range of variants being offered in terms of drives (front and/or rear-wheel drive, four-wheel or all-wheel drive); fully automatic, manual and/or automatically shifted manual transmission, further complicate the automotive designing.

Therefore, it is very important to analyze the vibration characteristics of the various vehicle substructures and mountings, e.g. K-frame substructure, including mode shapes, natural frequencies and dynamic stiffness of various mountings, e.g. engine mounts thereof. In short, dynamic stiffness of the substructures and mountings has a direct and significant effect on the NVH characteristics of any vehicle.

Accordingly, a thorough vehicle level analysis was conducted, which resulted in a strong objective correlation between the growling noise and the K-frame structure.

It was found that the second bending mode of the substructure (K-frame) was overlapping (modal coupling) with the power-train bending mode and resulted in a resonance and K-frame was weaker in the high frequency zone (due to its hollow section) and thus vibrations were transmitted to the vehicle body.

DISADVANTAGES WITH THE PRIOR ART

It was reported that NVH deteriorates due to the reduction in stiffness and poor damping characteristics. At present, the vehicle substructures, e.g. K-frame is stiffened for increasing bandwidth by modifying the cross-section or by providing a connection between the top and bottom plate of K-Frame. The higher frequency vibrations can also be reduced by increasing the thickness of the sheet metal plate. However, both these provisions lead to a substantial increase in the weight of the component.
The foam application also involves a complicated process requiring about six pieces to be stuck around the metal carrier. A hot chamber is also required to provide an appropriate environment for applying foam. Moreover, there is also substantial cost to be incurred on metal and foam and foam application process. In addition, the process also involves several steps, i.e. from metal carrier welding till foam application, which could only be resolved by integrating these components into a single unit.

OBJECTS OF THE INVENTION

Some of the objects of the present invention - satisfied by at least one embodiment of the present invention - are as follows:

An object of the present invention is to provide a light-weight substructure for vehicles.

Another object of the present invention is to provide a substructure for vehicles having improved NVH performance.

Still another object of the present invention is to provide a substructure for vehicles having enhanced sound quality of in-cab noise.

Yet another object of the present invention is to provide a substructure for vehicles having improved dynamic stiffness and higher damping.

A further object of the present invention is to provide a substructure for vehicles having increased modal separation bandwidth.

A still further object of the present invention is to provide a substructure for vehicles which includes a single integrated K-frame unit.

A yet further object of the present invention is to provide a substructure for vehicles, in which metallic portions are replaced by plastics.

One more object of the present invention is to provide a substructure for vehicles, in which foam quantity is reduced by using injection molded parts.

These and other objects and advantages of the present invention will become more apparent from the following description when read with the accompanying figures of drawing, which are, however, not intended to limit the scope of the present invention in any way.

DESCRIPTION OF THE PRESENT INVENTION

Therefore, there is an emphasis on deploying light-weight technology, e.g. thinning of materials or using light-weight materials, such as Aluminum or Magnesium. These materials have a specific weight of 0.6 only. Further, epoxy-based composite materials are preferred to counterbalance poor NVH performance in K-frames. These materials provide an improved dynamic stiffness and higher damping, which include high-strength compressive foam with improved dynamic stiffness. These also have superior bending performance due to their enhanced section integrity. In fact, this invention represents the first-ever application anywhere in the world, which use structural foam as a NVH solution on K-frame like components.

In accordance with the present invention, there is provided a vehicle substructure, e.g. K-frame or crossmember for improving the NVH performance by increasing the static and dynamic stiffness and damping characteristics thereof by using epoxy-based composite materials. This novel configuration reduces the overall noise and vibration levels within the vehicle and substantially enhances the sound quality of the in-cab noise of the vehicle. A light weight structural foam material, such as Teroson EP 1030 HX having a specific weight of just 0.6 is used in the K-frame for obtaining these desired characteristics.

The improvement in the structural dynamics is achieved with this light-weight material by increasing the modal separation bandwidth in a low frequency zone. The overall energy is dampened throughout the frequency spectra by this configuration. It is a high strength compressive foam with improved dynamic stiffness as well as a superior bending performance by enhancing the section integrity.

Here, K-frame acts as a mounting means, e.g. as an engine mount in the vehicle to reduce the vibration levels on passive side (in-cab) of the vehicle. In the conventional configuration, the second bending mode (276 Hz, refer to Figure 8) of the substructure (K-frame) overlapped (modal coupling, refer to Figure 11) with the power train bending mode (268 - 284 Hz) and resulted in a resonance.

However, it was weak in the high frequency zone (low damping), thereby transmitted power train vibrations to the vehicle body. Due to these undesirable characteristics, the high level of in-cab noise and deteriorating sound quality was witnessed inside the vehicle.

To overcome these issues, the application of Teroson EP 1070 was introduced in the inner section of the K-frame along with a metal foam carrier. This ensured that the second bending mode of the K-frame is completely decoupled from the power train bending mode. Further, the damping of the component is significantly improved up to the frequency ranges between 5 to 1000 Hz, which also helps in reducing the vibration levels and this in turn reduces the noise levels within the vehicle (in-cab noise).

This is the very first application using structural foam as an NVH solution on frame (e.g. S101 K-frame) like components anywhere in the world.

In accordance with the present invention, the structural foam (Teroson) is interposed between the outer panel and the foam carrier (sheet metal) to establish a continuous connection between the top and bottom panels. After going through electrodeposition (ED) process, the structural foam is cured to form solid bonding between top and bottom panels therethrough. Because of this bonding or integration, the static and dynamic stiffness along with the damping characteristics of the entire K-frame increases throughout the frequency spectra. Moreover, this enhanced performance is achieved without any increasing the weight of the component, as was necessary with the conventional approach to this problem.

The performance of the K-frame configured in accordance with the present invention, as discussed above, was also analyzed by Value Analysis Value Engineering (VAVE) using Teroson both with metal and plastic (Fig.5a and 5b) respectively. The result of this analysis are summarized below:

Teroson with metal Teroson with plastic Remarks
Weight 15.4 kg 15.2 kg Lower weight than conventional
K-frame
Material METAL + TEROSON
EP 1030HX PLASTIC 70G33HS1L
+
TEROSON EP1450 Lower cost than metal carrier K-frame
Advantage Noise reduction Better NVH results, Reduced process flow/work at supplier’s end Better NVH results

The idea underlying the present invention is to increase the bandwidth between the first and second mode of the substructure (K-frame) to avoid modal overlapping (modal coupling) with the engine bending mode. So, in principal, integration of the top and bottom panel (through the structural foam and foam Carrier) is done for increasing the dynamic stiffness of the substructure. A modal impact testing was carried out on this K-frame in the free-boundary condition. The results are summarized in graphical representations in the accompanying Figures 10 to 12.

SUMMARY OF THE PRESENT INVENTION

In accordance with the present invention, there is provided an integrated light-weight substructure for a vehicle to improve the NVH performance and in-cab sound quality thereof, wherein the substructure comprises an outer panel, an inner structural foam carrier and a foam interposed between the outer panel and the inner structural foam carrier by applying an epoxy-based composite material by heating during electrodeposition (ED) process and subsequently cured to form a solid bond therebetween to improve the dynamic stiffness and higher damping characteristics.

In an embodiment of the present invention, the integrated light-weight substructure is a cross-member or K-Frame of a vehicle.

In another embodiment of the present invention, the structural foam carrier is formed of combination of materials, preferably metal and high-strength compressive structural foam.

In still another embodiment of the present invention, the structural foam carrier is formed of a combination of materials, preferably plastic and high-strength compressive structural foam.

In a still further embodiment of the present invention, the substructure has specific weight of the order of 0.5 to 0.8, preferably 0.6.

In a yet further embodiment of the present invention, the K-Frame comprises a profiled outer panel, an inner profiled carrier of structural foam, which is interposed between the outer panel and the inner carrier after applying an epoxy-based composite material bonded by heating during an electrodeposition (ED) process and subsequently cured to form a solid bond therebetween and obtaining the integrated light-weight K-frame having an improved dynamic stiffness and higher damping characteristics.

In an additional embodiment of the present invention, the substructure has specific weight in the range of 0.5 to 0.8, preferably 0.6.
In accordance with the present invention, there is also provided a method for making an integrated light-weight substructure, wherein the method comprises the following steps:

• Making the outer panel;

• Making the inner structural foam carrier;

• Applying an epoxy-based composite material between the outer panel and inner structural foam carrier by means of heating electrodeposition (ED) process; and

• Curing the assembly of outer panel and the inner structural foam carrier applied with the epoxy-based composite material therebetween by heating above a predefined temperature and maintained in a heating oven for a predetermined duration to form a solid bond therebetween to obtain the integrated light-weight substructure.

In an embodiment of the method of the present invention, the heating is preferably carried out between 150 and 2000C, more preferably at approximately 1700C maintained in a heating oven preferably for 15 to 20 minutes, more preferably for about 17 minutes.

In another embodiment of the method of the present invention, the method produces crosslinked polymer having microspheres surrounding gas-filled hollows to improve section integrity to obtain superior bending performance by providing substantially lower point mobility and higher dynamic stiffness.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The present invention will be briefly described with reference to the accompanying drawings, which include:

Figure 1a shows a sectional view of the K-frame panel in accordance with the present invention.

Figure 1b shows a sectional view of the K-frame panel in accordance with the present invention.

Figure 2a shows a typical foam carrier (metal) sample configured in accordance with the present invention.
Figure 2b shows a typical foam carrier (plastic) sample configured in accordance with the present invention.

Figure 3a shows a typical foam carrier (metal) sample of Figure 2a placed on K-frame panel configured in accordance with the present invention.

Figure 3b shows the foam carrier (plastic) sample of Figure 2b placed on K-frame panel configured in accordance with the present invention.

Figure 4a shows the typical foam carrier (metal) sample of Figure 3a with structural foam configured in accordance with the present invention.

Figure 4b shows the typical foam carrier (plastic) sample of Figure 3b with structural foam configured in accordance with the present invention.

Figure 5a shows a typical K-Frame substructure configured according to the present invention as depicted in Figure 1a.

Figure 5b shows a typical K-Frame substructure (with metallic foam carrier) configured according to the present invention as depicted in Figure 5a.

Figure 5b shows a typical K-Frame substructure (with plastic foam carrier) configured according to the present invention as depicted in Figure 5a.

Figure 6a shows the graph depicting the acceleration plot at a predetermined point on the K-frame in accordance with the present invention.

Figure 6b shows another graph for the acceleration plot at a predetermined point on the K-frame in accordance with the present invention.

Figure 6c shows the graph depicting the acceleration plot taken on powertrain nearby the engine oil sump.

Figure 6d shows the graph depicting the acceleration plot taken on Powertrain nearby engine oil sump and torque attachment point on the K-frame for model coupling and decoupling.

Figure 7 shows a comparative graph for the modal criteria between the conventional K-frame and the K-frame with metallic and plastic foam carriers configured in accordance with the present invention respectively.

Figure 8a shows a cross-sectional view of structural foam before expansion.

Figure 8b shows a cross-sectional view of the structural foam after expansion.

Figure 9a shows a bottom view of the first embodiment of the K-Frame substructure of Figure 5a with multiple measurement locations thereon.

Figure 9b shows a top view of the second embodiment of K-Frame substructure of Figure 5a with multiple measurement locations.

Figure 10a shows a comparative graph of the conventional K-frame and K-frame with metallic and plastic foam carriers, depicting energy level reduction.

Figure 10b shows a comparative graph of the conventional K-frame and K-frame with metallic and plastic foam carriers, depicting energy level reduction.

Figure 10c shows a comparative graph of the conventional K-frame and K-frame with metallic and plastic foam carriers, depicting energy level reduction.

Figure 10d shows a comparative graph of the conventional K-frame and K-frame with metallic and plastic foam carriers, depicting energy level reduction.

Figure 10e shows a comparative graph of the conventional K-frame and K-frame with metallic and plastic foam carriers, depicting energy level reduction.

Figure 10f shows a comparative graph of the conventional K-frame and the K-frame with metallic and plastic foam carriers, depicting energy level reduction.

Figure 11a shows a comparative graph depicting the conventional K-frame and K-frame of Figure 5a configured with metallic and plastic foam carriers for representing the dynamic stiffness at K-frame centers.

Figure 11b shows another comparative graph depicting the conventional K-frame and K-frame of Fig. 5b configured with metallic and plastic foam carriers for representing dynamic stiffness at K-frame centers.

Figure 11c shows a comparative graph for one of the models depicting the conventional K-frame and K-frame configured with metallic and plastic foam carriers for representing the dynamic stiffness at the K-frame centers.

Figure 12 shows a comparative graph for the conventional K-frame and K-frame of Figure 9a configured with the metallic and plastic foam carriers for representing vehicle level Frequency Response Function at point 1001.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

In the following, different embodiments of the present invention will be described in more details with reference to the accompanying drawings without limiting the scope and ambit of the present invention in any way.

Figure 1a shows the sectional view of the typical K-frame substructure in accordance with the present invention configured for improving NVH performance and enhancing the sound quality of in-cab noise. The K-frame section includes an outer panel A of sheet metal, a sheet metal panel as structural foam carrier B and a structural foam C of TERACORE disposed between the outer panel A and the structural foam carrier B. Initially, the structural foam (which is in a semi-solid state) is applied on the surface area of structural foam carrier B (sheet metal panel) within an appropriate thickness. Then, it is sandwiched between the K-Frame top and bottom panels and finally joined by welding. Subsequently, the assembly is passed through the oven for baking (approximately at above 1700C) the foam. Finally, the assembly is allowed to cool down. The structural foam will solidify while being passed through the curing process carried out for about 17 minutes at above 1700C. This subsystem behaves as a single mass system having increased static and dynamic stiffness characteristics. Thereby, a significant performance improvement is observed throughout the frequency spectra.

Figure 1b shows a sectional view of the K-frame panel in accordance with the present invention. Here, the K-Frame is sectioned to show that the structural foam completely interposed all over the area.

Figure 2a shows a typical foam carrier (metal) sample configured in accordance with the present invention. The foam carrier is made by following the same contour as the interior of the K-frame with close to 5 mm offset (to fill the gap with the structural foam) taken from the inner edge.

Figure 2b shows a typical foam carrier (plastic) sample configured in accordance with the present invention. The foam carrier is made by following the same contour as the interior of the K-frame with close to 5 mm offset (to fill the gap with the structural foam) taken from the inner edge.

Figure 3a shows a typical foam carrier (metal) sample of Figure 2a placed on K-frame panel configured in accordance with the present invention. Here, Teroson EP 1030 is applied on the exterior surface of the foam carrier. The thickness of the foam is optimized and used accordingly. Here, e.g. 6 pieces must be pasted around the metal carrier, which makes the foam application process very complicated due to more number of steps. Metallic carrier is also quite heavy and an appropriate atmosphere in the hot chamber is required during foam application. This makes the overall cost of the K-frame higher. Here, a lower point mobility and higher dynamic stiffness is found better.

Figure 3b shows the foam carrier (plastic) sample of Figure 2b placed on K-frame panel configured in accordance with the present invention. Here, different assemblies are integrated into a single unit by using plastic carrier instead of metallic carrier. This reduces the required foam quantity due to reduced number of steps and because of possibility of using injection molding process. This substantially reduces the weight of the K-frame and overall production cost thereof. Here as well, a lower point mobility and higher dynamic stiffness is considered to be better.

Figure 4a shows the typical foam carrier (metal) sample of Figure 3a with structural foam configured in accordance with the present invention.

Figure 4b shows the typical foam carrier (plastic) sample of Figure 3b with structural foam configured in accordance with the present invention.

Figure 5a shows a typical K-Frame substructure configured according to the present invention as depicted in Figure 1a. The four ends of the K-Frame are connected to vehicle body and the powertrain is connected through torque rod at the center position of the K-Frame. The impact locations are highlighted in “YELLOW”. It is to be noted that a lower point mobility and higher dynamic stiffness is considered to be better.

Figure 5b shows a typical K-Frame substructure (with metallic foam carrier) configured according to the present invention as depicted in Figure 5a. This shows the K-frame obtained after electrodeposition (ED) and baking.

Figure 5c shows a typical K-Frame substructure (with plastic foam carrier) configured according to the present invention as depicted in Figure 1. This also shows the K-frame obtained after electrodeposition (ED) and baking.

Figure 6a shows the graph for the acceleration recorded near the torque rod attachment point on K-frame configured in accordance with the present invention. As desired, no peak is observed in the frequency range of 240 to 310 Hz (second bending mode is at 272 Hz), meaning that the second bending mode of the K-frame is completely decoupled from the power train bending mode (268 - 284 Hz). The dotted line represents the conventional K-Frame, whereas the continuous line represents the K-Frame configured in accordance with the present invention. Here, the frequency (in Hz) is represented on X axis and the acceleration (in m/s2) is represented on Y axis.
Figure 6b shows the graph for the acceleration recorded near the torque rod attachment point on K-frame configured in accordance with the present invention. A significant reduction (up to 98%) is observed in the energy levels in the frequency range of 5-1000 Hz, when tested at multiple locations. This acceleration plot is same as the acceleration plot depicted in Figure 6a, however it shows the frequency spectrum up to 1000 Hz. Here also, the frequency (in Hz) is represented on X axis and the acceleration (in m/s2) is represented on Y axis.

Figure 6c shows the graph for the acceleration recorded on powertrain nearby the engine oil sump. This mode also affects the adjacent frequency zone. Here also, the frequency (in Hz) is represented on X axis and the acceleration (in m/s2) is represented on Y axis. From the above graphical representations, it is abundantly clear that this innovative configuration of the K-frame substructure configured in accordance with the present invention is very useful for reducing the overall noise and vibration levels to enhance the in-cab sound quality of the vehicle. The powertrain bending is present in a 268-284 Hz band.

Figure 6d shows the coupling between powertrain bending mode and the conventional K-frame. In the same graph, it is also shown how the proposed mode is decoupled with the powertrain bending mode by shifting the second bending (272 Hz) mode for the K-Frame. Here, the frequency (in Hz) is represented on X axis and the acceleration (in m/s2) is represented on Y axis.

Figure 7 shows a comparative graph for the modal criteria for the conventional K-frame as well as the K-frame in accordance with the present invention, configured with metallic and plastic foam carriers respectively. It is obvious from this graph that there is no peak acceleration in the frequency range of 240-310 Hz.

Figure 8a shows the cross-sectional view of a typical structural foam, e.g. Teroson EP 1070 before expansion. Here, uncured polymer 60 containing a plurality of microspheres 70 are enclosed between the substrate layer gap 100.

Figure 8b shows the cross-sectional view of a typical structural foam, e.g. Teroson EP 1070 after expansion. Here cross-linked polymer 80 containing a plurality of microspheres 70 and hollows 90 are enclosed between substrate layers 100.

Figure 9a shows a bottom view of the first embodiment of the K-Frame substructure of Figure 5a with multiple measurement locations 1001, LHS 1002 and RHS1002 disposed thereon. These impact locations are highlighted in “YELLOW”. It is to be noted that a lower point mobility and higher dynamic stiffness is considered to be better.
Figure 9b shows a top view of the second embodiment of the K-Frame substructure of Figure 5a with multiple measurement locations 2001, LHS 2002 and RHS 2002 disposed thereon. These impact locations are highlighted in “YELLOW”. It is to be noted here that a lower point mobility and higher dynamic stiffness is considered to be better.

Figure 10a shows a comparative graph of the conventional K-frame and the K-frame with metallic and plastic foam carriers, depicting the energy level reduction at the location 1001 shown in Figure 9a. It is obvious from the graphs that the point mobility of K-frame with metallic and plastic foam carriers according to the invention is lower than that of the conventional K-frame.

Figure 10b shows a comparative graph of the conventional K-frame and the K-frame with metallic and plastic foam carriers, depicting the energy level reduction at the location LHS 1002 shown in Figure 9a. It is obvious from the graphs that the point mobility of K-frame with metallic and plastic foam carriers according to the invention is lower than that of the conventional K-frame.

Figure 10c shows a comparative graph of the conventional K-frame and the K-frame with metallic and plastic foam carriers, depicting the energy level reduction at the location RHS 1002 shown in Figure 9a. It is obvious from the graphs that the point mobility of K-frame with metallic and plastic foam carriers according to the invention is lower than that of the conventional K-frame.

Figure 10d shows a comparative graph of the conventional K-frame and the K-frame with metallic and plastic foam carriers, depicting the energy level reduction at the location 2001 shown in Figure 9b. It is obvious from the graphs that the point mobility of K-frame with metallic and plastic foam carriers according to the invention is lower than that of the conventional K-frame.

Figure 10e shows a comparative graph of the conventional K-frame and the K-frame with metallic and plastic foam carriers, depicting the energy level reduction at the location LHS 2002 shown in Figure 9b. It is obvious from the graphs that the point mobility of K-frame with metallic and plastic foam carriers according to the invention is lower than that of the conventional K-frame.

Figure 10f shows a comparative graph of the conventional K-frame and the K-frame with metallic and plastic foam carriers, depicting the energy level reduction at the location RHS 2002 shown in Figure 9b. It is obvious from the graphs that the point mobility of K-frame with metallic and plastic foam carriers according to the invention is lower than that of the conventional K-frame.
Figure 11a shows a comparative graph for depicting conventional K-frame and K-frame of Figure 5a configured with metallic and plastic foam carriers for representing the dynamic stiffness at K-frame centers thereof. It is to be noted that a higher dynamic stiffness is considered to be better. It is obvious from the graphs that the dynamic stiffness of K-frame with metallic and plastic foam carriers according to the invention is higher than that of the conventional K-frame.

Figure 11b shows another comparative graph depicting the conventional K-frame and K-frame of Figure 5b configured with metallic and plastic foam carriers for representing the dynamic stiffness at K-frame centers thereof. It is obvious from the graphs that the dynamic stiffness of K-frame with metallic and plastic foam carriers according to the invention is higher than that of the conventional K-frame.

Figure 11c shows a comparative graph for one of the models depicting the conventional K-frame and K-frame configured with metallic and plastic foam carriers for representing the dynamic stiffness at the K-frame centers thereof. Here as well, it is obvious from the graphs that the dynamic stiffness of K-frame with metallic and plastic foam carriers according to the invention is higher than that of the conventional K-frame.

Figure 12 shows a comparative graph for the conventional K-frame and K-frame of Figure 9a respectively configured with the metallic and plastic foam carriers for representing the vehicle level Frequency Response Function (FRF) at point 1001 thereof. Here also, a lower point mobility is considered better. Here, from the graphs, the point mobility of K-frame with metallic and plastic foam carriers made according to invention appears lower than that of the conventional K-frame.

TECHNICAL ADVANTAGES AND ECONOMIC SIGNIFICANCE

The light-weight substructure for vehicles for improving NVH performance and enhancing the sound quality of in-cab noise of the vehicle configured in accordance with the present invention has the following advantages:

• Facilitates in obtaining a light-weight substructure for a vehicle.
• Offers improved NVH performance.
• Enhanced sound quality of in-cab noise.
• Offers increased stiffness.
• Provides improved damping characteristics.
• Decrease modal density.
• Integration of carrier with foam eliminated the assembly time thus enhanced productivity.
• Less foam quantity leads to overall cost-reduction with improved NVH.

Throughout this specification, the word “comprise”, or variations such as “comprises” or “comprising”, shall be understood to implies including a described element, integer or method step, or group of elements, integers or method steps, however, does not imply excluding any other element, integer or step, or group of elements, integers or method steps.

The use of the expression “a”, “at least” or “at least one” shall imply using one or more elements or ingredients or quantities, as used in the embodiment of the disclosure in order to achieve one or more of the intended objects or results of the present invention.

The exemplary embodiments described in this specification are intended merely to provide an understanding of various manners in which this embodiment may be used and to further enable the skilled person in the relevant art to practice this invention. The description provided herein is purely by way of example and illustration.

Although the embodiments presented in this disclosure have been described in terms of its preferred embodiments, the skilled person in the art would readily recognize that these embodiments can be applied with modifications possible within the spirit and scope of the present invention as described in this specification by making innumerable changes, variations, modifications, alterations and/or integrations in terms of materials and method used to configure, manufacture and assemble various constituents, components, subassemblies and assemblies, in terms of their size, shapes, orientations and interrelationships without departing from the scope and spirit of the present invention.

While considerable emphasis has been placed on the specific features of the preferred embodiment described here, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiments without departing from the principles of the invention. These and other changes in the preferred embodiment of the invention will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation. ,CLAIMS:We claim:

1. An integrated light-weight substructure for a vehicle to improve the NVH performance and in-cab sound quality thereof, wherein the substructure comprises an outer panel, an inner structural foam carrier and a foam interposed between the outer panel and the inner structural foam carrier by applying an epoxy-based composite material by heating during electrodeposition (ED) process and subsequently cured to form a solid bond therebetween to improve the dynamic stiffness and higher damping characteristics.

2. Integrated light-weight substructure as claimed in claim 1, wherein the substructure is a cross-member or K-Frame of a vehicle.

3. Integrated light-weight substructure as claimed in claim 1, wherein the structural foam carrier is formed of a combination of materials, preferably a metal and a high-strength compressive structural foam.

4. Integrated light-weight substructure as claimed in claim 1, wherein the structural foam carrier is formed of a combination of materials, preferably plastic and a high-strength compressive structural foam.

5. Integrated light-weight substructure as claimed in anyone of the claims 1 to 4, wherein the substructure has specific weight of the order of 0.5 to 0.8, preferably 0.6.

6. An integrated light-weight K-Frame for a vehicle to improve the NVH performance and in-cab sound quality thereof, wherein the K-Frame comprises a profiled outer panel, an inner profiled carrier of structural foam, which is interposed between the outer panel and the inner carrier after applying an epoxy-based composite material bonded by heating during an electrodeposition (ED) process and subsequently cured to form a solid bond therebetween and obtaining the integrated light-weight K-frame having an improved dynamic stiffness and higher damping characteristics.

7. Integrated light-weight K-Frame as claimed in claim 6, wherein the substructure has specific weight in the range of 0.5 to 0.8, preferably 0.6.

8. A method for making an integrated light-weight substructure as claimed in anyone of the claims 1 to 7, wherein the method comprises the following steps:
• Making the outer panel;

• Making the inner structural foam carrier;

• Applying an epoxy-based composite material between the outer panel and inner structural foam carrier by means of heating during the electrodeposition (ED) process; and

• Curing the assembly of outer panel and the inner structural foam carrier applied with the epoxy-based composite material therebetween by heating above a predefined temperature, maintained in a heating oven for a predetermined duration to form a solid bond therebetween to obtain the integrated light-weight substructure.

9. Method for making a light-weight substructure as claimed in claim 8, wherein heating is preferably carried out between 150 and 2000C, more preferably at approximately 1700C maintained in a heating oven preferably for 15 to 20 minutes, more preferably for 17 minutes.

10. Method as claimed in claim 9, wherein the method produces crosslinked polymer having microspheres surrounding gas-filled hollows to improve section integrity to obtain superior bending performance by providing substantially lower point mobility and higher dynamic stiffness.

Dated: this day of 06th January, SANJAY KESHARWANI
APPLICANT’S PATENT AGENT