Claims:
CLAIMS:

I/We claim:

1. A monocoque body structure assembly for an automobile comprising:
a front Floor structure, a middle floor structure, a rear floor Structure, a left structure, a right structure, a roof structure, a front module, a rear Module, a battery module
Wherein,
the front Floor structure is supportively connected with the roof structure, the rear floor Structure, and the middle floor structure.
2.The assembly as claimed in claim 1, wherein the battery unit is detachably attached below middle floor.
3.The vehicle Monocoque electric body assembly as claimed in claim 2, wherein the removable mountings make the battery pack replaceable.
4. The assembly as claimed in claim 1, wherein the material used for the structure are IS 4923, IS: 2062.
, Description:TITLE OF THE INVENTION:
“Improved Monocoque Electric Bus Structure’’

FIELD OF THE INVENTION
The invention relates to automobile structure. More specifically, the present invention relates to uniform distribution of load.

SUMMARY OF THE INVENTION

In view of the foregoing, an embodiment herein provides a system and a method for an automobile comprising, a front Floor structure, a middle floor structure, a rear floor Structure, a left structure, a right structure, a roof structure, a front module, a rear Module, a battery module, wherein, the front Floor structure is supportively connected with the roof structure, the rear floor Structure, and the middle floor structure.
According to an embodiment, the battery unit is detachably attached below the middle floor structure.
According to an embodiment, the removable mountings make the battery pack replaceable.
Further, the material used for the structure are IS 4923, IS: 2062.
These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, ae given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

BRIEF DESCRIPTON OF DRAWINGS:

The novel features and characteristics of the disclosure are set forth in the description. The disclosure itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following description of an illustrative embodiment when read in conjunction with the accompanying drawings. One or more embodiments are now described, by way of example only, with reference to the accompanying drawings wherein like reference numerals represent like elements and in which:
Fig. 1 illustrates a schematic representation of various sub systems used in electric bus structure, according to one or more embodiment of the invention.
Fig. 2 illustrates a schematic design representation of electric bus structure, according to one or more embodiments of the present disclosure.
Fig. 3 illustrates a schematic representation of battery integration in electric bus structure, according to one or more embodiments of the present disclosure.
The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the assemblies, structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.

DETAILED DESCRIPTION OF THE INVENTION:

The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments and detailed in the following description. Descriptions of well-known components and processing techniques are omitted to not unnecessarily obscure the embodiment herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
The existing traditional Bus structures are bulky; hence it requires more traction power to drive the vehicle resulting into more power consumption and lesser range or milage. While majority of OEM’s are converting their existing IC Engine Buses having ladder type of chassis into Electric Buses. Though, it has advantage to launch the passenger bus in lesser time however it has limitation to reduce mass or redistribute it into entire bus structure.
Further, the stainless-steel buses are certainly not new, the present invention reveals opportunities for substantial improvements in structural performance.
The present invention discloses Monocoque Bus Body structure, as shown in Fig 1 that provides flexibility to distribute mass resulting into better integration of sub systems into vehicle. The objective of this invention is to focus on the mass saving potential of ultra-high strength stainless steel (SS409M) as applied to the structure of a full-size urban city bus. The resulting design for a low floor, electric bus has an empty weight 30% less than that of a conventional city bus. The reduced curb weight allows for a greater payload, without exceeding legal axle limits. A combination of finite element modeling and dynamic testing of models was used to predict structural performance.
In one embodiment of the invention, the major weight contributors such as battery, traction motor below floor are condensed together by maintaining ground clearance and other dimensional requirements in Bus Body Code which results in better stability of vehicle. Thus, reduction of Mass has improved the range of the Bus.
In another embodiment of the invention, the used material consists of high specific strength to save the mass factor. The qualitative load path geometry was quantified using finite element analysis. Optimum stiffness is achieved by load path analysis and optimization study in given constraints. Further, the bus structure mass was dictated by strength requirements. By choosing a material with a high specific strength, such as stainless steel (SS 409M), significant mass reductions have been achieved.
In yet another embodiment of the invention, the bench marked different vehicles in the same category are compared with the weight, center of gravity, stability angle, and design modularity.
As shown in Fig 1 & 2, the vehicle is divided into following sub-assemblies, to make it modular structure; a) Front Floor Structure cum Chassis, b) Middle Floor Structure cum Chassis, c) Rear Floor Structure cum Chassis, d) Left Structure e) RH Structure f) Roof Structure g) Front Module, h) Rear Module.
Moreover, the Battery packaging in lower floor bus is a challenge. One battery pack mass is 620 Kg, and its dimensions were 1680X1370X205 and two battery packs had to be placed below the floor structure by maintaining all dimensional requirements as shown in Fig 2.
Fig 3 depicts the removable mountings which were provided so that the battery pack can be easy replaced. Durability Analysis were conducted to check mounting strength, and other analysis performed to ensure battery safety in extreme operating conditions or in case of accidents.
In the same way other sub-assemblies (compressor, AC, Traction Motor, Steering Pump etc.) were packaged and CAE analysis done for strength and durability analysis.
Further, the Natural frequency analysis, Load path analysis, sensitivity analysis torsional stiffness and bending stiffness is calculated in CAE by using software tools.
Although, traditional materials like IS 4923, IS: 2062 are quite popular in Bus Body Structure application. However, these materials show limitations such as lesser corrosive resistance property, requires coating i.e., paints etc. to increase its life. Paint shops are huge investments also adds to environment degradation.
In this way number of parts can be reduced to make standard system Passenger. Bus structure involves hundreds of parts which on reducing can minimize cost (purchase, operation, life cycle) and show improved performance, usability, comfort.
Taking consideration of the Vehicle Stability, the traditional Ladder type chassis vehicles have higher C.G in vertical axis when measured from Ground thus resulting into less vehicle stability (stability angle less than 30 degree).
However, the monocoque chassis show improved stability due to better mass packaging below floor resulting into stability angle improves up to 45 degrees.
The C.G. location is as following:
X= 2783.88 mm Rearward from Front Axle Center
Y= 3.74 mm towards Co-Driver (LH) side from VLCP
Z= 1208.54 mm above Ground Level
In further embodiment of the invention, it was determined that a “low floor” configuration, was desirable to facilitate improved passenger capacity, flow patterns, and usability. Other features of the basic vehicle architecture were selected, in part, for their inherent synergistic compatibility with a low floor configuration. For example, the monocoque type structure allows a low floor height while maintaining ground clearance and providing a very efficient structure. The electric powertrain, in addition to reducing overall mass and increase range, also minimized interior intrusion, and enabled the repositioning of the powertrain under the rear floor. With a good understanding of the basic vehicle architecture and its requirements, the detailed design of the body structure proceeded.
The following major parameters were compared with existing ladder type chassis bus structure designs.
Weight:
Ladder type of chassis Bus structure weight (Kg) = 1800
Our Bus structure design by using stainless steel SS 409 M = 1150
Weight Saving (Kg.) = 650
Weight saving in % = 35%

The result of the design and analysis as given below is an FEA calculated Body structure weight of 1100 Kg. This represents a reduction in mass compared with a conventional bus. The lower curb weight allows for increase in payload without exceeding legal axle limits. In other words, more passengers can be carried on the same size bus.
In further embodiment of the invention, SS 409M (EN 1.4003) highly corrosion resistant material is used as compared to IS:4923.

In yet further embodiment of the invention, the improved stability achieved is 45 degrees as compared to conventional chassis bus structure. It means vehicle can tilt up to 45 degrees without falling in rollover.
Moreover, the design Modularity is easy for making multiple variants and is not restricted as compared to old bus designs. The avoidance of use of paint used causes less pollution as compared to traditional bus manufacturing thus contributing to environment protection.
Different grade material based on functional and strength requirements, can be used to achieve optimum mass and cost of the complete Bus body structure
While the entire bus was designed for cost-effective manufacture, there is not yet a specific cost analysis to support a claim of actual cost reduction. However, certain logical statements can be made:
In one exemplary embodiment of the invention, the cost of SS409M is slightly less than 304 stainless (used on other SS bus designs).
Furthermore, less material is required due to the reduced mass of the structure and the labor content for assembly is very low. The tooling investment is very low. On summarizing these factors, the advantages of them for lowering the cost of manufacture relative to existing bus designs is observed.