WO2021063926A1

WO2021063926A1 - Vehicle rear structure

Info

Publication number: WO2021063926A1
Application number: PCT/EP2020/077193
Authority: WO
Inventors: Gaetano TROIANO
Original assignee: Troiano Gaetano
Priority date: 2019-10-01
Filing date: 2020-09-29
Publication date: 2021-04-08
Also published as: LU101416B1

Abstract

A structure for the rear section of a vehicle is disclosed, together with a method of manufacturing a vehicle with same. The structure comprises an enclosure accessible through a latched body panel of the vehicle. The enclosure includes an inner bottom surface and an outer bottom surface in opposition to each other and jointly defining a firewall. First and second portions of the outer bottom surface include respectively first and second recesses, dimensioned to accommodate respectively first and second propellant tanks. At least the first portion is located within a boundary defined by one or more peripheral sections of the vehicle chassis and located between a rearmost of the one or more peripheral section(s) of the chassis and a rearmost axle of the vehicle. A depth of the first recess relative to the outer bottom surface is less than a maximum height of the one or more peripheral chassis section(s) relative to a surface on which the vehicle rests or travels.

Description

VEHICLE REAR STRUCTURE

Field of the Invention

[001] The present invention relates to a structure for the rear section of a vehicle. More particularly, the present invention relates to a structure for accommodating a propellant tank.

Background to the Invention

[002] Vehicles which generate a self-propelling motive force through an internal combustion engine are conventionally equipped with a propellant tank located substantially underneath and generally rearward of the vehicle. A recent tendency, aided by improvements in both pre-programmed vehicle deformation and fire hazard mitigation, has been to locate the propellant tank directly underneath the habitat section, in order to best adjust the gravity centre of the vehicle.

[003] Aftermarket techniques based upon alternative propellants have been developed to help improve vehicle autonomy and running costs, typically in cases involving gas-fuelled vehicles with relatively poor fuel economy. A well-known aftermarket development is based upon the use of liquid petroleum gas (‘LPG’) as an alternative to regular gas, with a requirement to retrofit a distinct tank in the vehicle.

[004] Notwithstanding the promulgation of stringent safety standards for their design and fitting, such aftermarket solutions remain highly dangerous to use, because the LPG stored in the dedicated tank is both highly pressurised and highly flammable, and such tanks are routinely retrofitted at the rear of a vehicle, typically within a rear enclosure, such as the trunk of a car, that is separated from the vehicle habitat and its occupants by relatively soft and flammable partitioning like rear car seats or a carpeted panel. [005] In parallel to the above, complex exhaust purification systems have also been developed to help mitigate the deleterious effects of vehicle exhaust gases upon the environment, moreover according to ever more restricted levels of exhausted particles deemed harmful. Modern vehicles now routinely include solution-based exhaust purification systems based upon an aqueous urea or ammonia solution, again requiring a distinct solution tank to be mounted within the vehicle.

[006] Accordingly, there has been a proliferation of tanks to be mounted in modern vehicles for a variety of economic and regulatory reasons, and a corresponding need to locate a suitable mounting volume for those, typically within the overall volume of a vehicle body shell so as to mitigate both environmental wear and impact forces in case of accidents. The prior art shows a relatively common approach, rendered conflictual in view of the rising number of distinct tanks to mount, of repurposing a vehicle’s spare wheel well, typically located within and accessible from the trunk of the vehicle, to lodge an aftermarket LPG tank (FR 2777513, CN 204309593) or a urea or ammonia solution tank (JP 2008265689). US 2015/0183317 and US 2006/0033322 disclose alternative techniques of the prior art. [007] Accordingly there is a requirement for an improved structure for the rear section of a vehicle, apt to increase the operational safety of fuelling a vehicle from a liquid petroleum gas tank, without however sacrificing more useful internal volume relative to known solutions. Summary

[008] The present invention mitigates shortcomings associated with the prior art of reference by modifying the conventional configuration of a floor of a vehicle trunk.

[009] According to an aspect of the present invention, there is provided a structure for the rear section of a vehicle, the structure comprising an enclosure accessible through a latched body panel of the vehicle. The enclosure includes inner and outer bottom surfaces in opposition to each other. A first portion of the outer bottom surface includes a first recess dimensioned to accommodate a first propellant tank. A second portion of the outer bottom surface includes a second recess dimensioned to accommodate at least a portion of a second propellant tank. At least the first portion of the outer bottom surface is bounded by one or more peripheral section(s) of a chassis of the vehicle and located between a rearmost of the one or more peripheral section(s) of the chassis and a rearmost axle of the vehicle. A depth of the first recess relative to the outer bottom surface is less than a maximum height of the one or more peripheral chassis section(s) relative to a surface on which the vehicle rests or travels. The inner and outer and bottom surfaces jointly define a firewall.

[0010] . This configuration increases the safety of vehicle occupants in case of a rear- aspect impact, by repurposing the vehicle rear axle as a physical barrier intermediate the first propellant tank and both the lower portion of the vehicle habitat and the second propellant tank if present, and by ensuring that the first recess is fully surrounded by the vehicle chassis whereby, subject to the severity of the impact, the chassis absorbs all or most of impact forces before they transfer to the first recess and the first propellant tank housed therein.

[0011] In an embodiment of the structure, the outer bottom surface is substantially parallel to the inner bottom surface, and the inner bottom surface is concave relative to the enclosure. Advantageously, the inner and outer bottom surfaces can then be two opposed faces of a same fireproof bulkhead, stamped or otherwise deformed to create the first recess in a single operation, whilst preserving the material and structural integrity of the bulkhead.

[0012] Embodiments of the structure are particularly well suited to accommodate a liquefied petroleum gas (‘LPG’) tank as the first propellant tank, wherein the second propellant tank is a gas or diesel tank conventionally located underneath the vehicle habitat partly or fully forward of the enclosure.

[0013] In an embodiment of the structure, the first recess may be shaped as an elliptical cylinder, oriented transverse to a plane defined by the outer bottom surface. The first recess may for instance be embodied centrally of the enclosure’s inner and outer bottom surfaces, effectively as an inverted spare wheel well. This embodiment is particularly well suited to accommodate substantially toroidal first propellant tanks.

[0014] In an alternative embodiment of the structure, the first recess may be shaped as a rectangular prism, oriented parallel to a plane defined by the outer bottom surface. The first recess may for instance be embodied parallel to the rear axle and adjacent an edge of the enclosure, either proximal or distal the adjacent habitat. This embodiment is particularly well suited to accommodate substantially cylindrical first propellant tanks.

[0015] A removable panel adapted to cover the first recess and the first propellant tank therein may usefully be provided for any of the structure embodiments introduced herein, in order to facilitate access for inspection and maintenance of the first propellant tank.

[0016] According to another aspect of the present invention, there is also provided a method of manufacturing a vehicle, comprising steps of providing a floor for a rear section of the vehicle, the floor having inner and outer bottom surfaces opposed to each other and made of a material impervious to fire ; shaping a first portion of the outer bottom surface of the floor with a first recess dimensioned to accommodate a first propellant tank ; shaping a second portion of the outer bottom surface with a second recess dimensioned to accommodate at least a portion of a second propellant tank; providing a chassis for the vehicle and locating the floor relative thereto, so that at least the first recess is bounded by one or more peripheral section(s) of the chassis, located between a rearmost of the one or more peripheral section(s) of the chassis and a rearmost axle of the vehicle, less than a maximum height of the one or more peripheral chassis section(s) relative to a surface on which the vehicle rests or travels ; and securing the first propellant tank in the first recess.

[0017] In an embodiment of the structure, wherein the outer bottom surface is substantially parallel to the inner bottom surface, the step of shaping may further comprise shaping the inner bottom surface to be concave relative to the enclosure. This embodiment advantageously provides the same benefit of single-operation stamping, or otherwise deforming, a unitary fireproof bulkhead so as to create the first recess whilst preserving the material and structural integrity of the bulkhead.

[0018] According to a further aspect of the present invention, there is also provided a vehicle comprising an embodiment of the structure introduced hereinabove, or manufactured according to an embodiment of the method introduced hereinabove. An embodiment of the vehicle may thus comprise a liquefied petroleum gas tank located within the first or second recessed portion.

[0019] According to yet another aspect of the present invention, there is also provided a propellant tank for use with embodiments of the structure, or of the method of vehicle manufacturing, or of the vehicle, all introduced hereinabove.

[0020] Other aspects of the present invention are as stated in the appended claims.

Brief Description of the Drawings

[0021] The invention will be more clearly understood from the following description of an embodiment thereof, given by way of example only, with reference to the accompanying drawings, in which

Figure 1 is a perspective view of a vehicle underside, having a rear section structure according to an embodiment of the invention ;

Figure 2 is an orthogonal view of the vehicle underside of Figure 1 ;

Figure 3 is a lateral view, partially in section, of the vehicle of Figures 1 and 2, having a rear section structure according to another embodiment of the invention ; Figure 4 is a lateral view, partially in section, of the vehicle of Figures 1 to 3, having a rear section structure according to a further embodiment of the invention ;

Figure 5 is a perspective cutaway view of the vehicle of Figure 4 ; and

Figure 6 is a lateral view of yet another embodiment of the rear section structure.

Detailed Description of the Drawings

[0022] There will now be described by way of example a specific mode contemplated by the inventors. In the following description numerous specific details are set forth in order to provide a thorough understanding. It will be apparent however, to one skilled in the art, that the present invention may be practiced without limitation to these specific details. In other instances, well known methods and structures have not been described in detail so as not to unnecessarily obscure the description.

[0023] A vehicle 10 is shown in Figures 1 to 5, wherein like reference numerals designate like features. In the example, the vehicle is a personal automobile with a body shell of the sedan type, having a habitat section 20 located intermediate a front section 30 housing an internal combustion engine 32 atop a front axle 34, and a rear section 40 comprising an enclosure 42 atop a rear axle 44, wherein the enclosure is accessible through a latched body panel 54 of the vehicle. The enclosure 42 in this embodiment defines a rear trunk of the vehicle 10, in which a user may place a load for transport.

[0024] The enclosure 42 extends over substantially the width of the vehicle rear axle 44 and comprises a floor 50 and peripheral walls 52_{A D} extending upwards from the floor, respectively : one wall 52_A rearmost of the vehicle and another wall 52_B intermediate the enclosure volume and the habitat section 20, wherein both are substantially parallel to each other and to the rear axle 44 ; and two walls 52_C,D parallel to each other, perpendicular to the rear axle 44 and laterally bounding the enclosure volume. The enclosure 42 further comprises the latched panel 44, which is substantially parallel to the floor 50 and conventionally hinged about a top aspect of the wall 52_B extending between the enclosure volume and the habitat section 20.

[0025] The floor 50 of the enclosure 42 includes an inner bottom surface 60 for accommodating a load which the user may place therein for transport, and an outer bottom surface 70 opposed to the inner bottom surface 60 and facing the ground underneath the vehicle 10. In the embodiment shown and described, the inner and outer bottom surfaces 60, 70 are opposed faces of a unitary sheet, which is preferably made of a material substantially impervious to fire, whereby the inner and outer and bottom surfaces jointly define a firewall 50.

[0026] In this embodiment, a first portion 72 of the outer bottom surface 70 includes a first recess dimensioned to accommodate a first propellant tank 80, in the example a toroidal LPG tank 80. Accordingly, the material of the floor still preferably exhibits structural characteristics apt to withstand an involuntary explosion of the LPG tank 80 adjacent to the outer bottom surface 70. [0027] In this embodiment, the first portion 72 of the outer bottom surface 70 is located between the rearmost wall 52_A of the enclosure 42 and the rear axle 44 of the vehicle 10. Alternative embodiments are contemplated, wherein the first portion 72 may be located partially or even fully atop the rear axle 44, in dependence on the design of the vehicle body shell, particularly in the case of hatchback types, typically having wheel axles located more proximate each corner of the vehicle.

[0028] In an embodiment shown in Figure 3, a removable and/or hinged panel 76 is provided to cover the first recess 72 and the first propellant tank 80 therein, in order to impede the ingress of dust, particles, moisture and various other types of environmental projections and contaminants in and around the tank 80. The panel 76 is preferably made of the same material substantially impervious to fire as the floor sheet 50, and its latching and/or hinging mechanism(s) are preferably configured to withstand, even if only partially, an involuntary explosion of the LPG tank 80 within the first recess.

[0029] In an embodiment shown in Figures 4 and 5, a depth D of the first recess 72 relative to the outer bottom surface 70, is less than a maximum height of peripheral sections 90 of the vehicle chassis, relative to the ground on which the vehicle 10 rests. [0030] With reference to Figure 6, when the vehicle engine 32 may be alternatively fuelled with a gas or diesel propellant, a second portion 74 of the outer bottom surface 70 of the floor 50 of the enclosure 42 includes a second recess dimensioned to accommodate at least part of a second propellant tank, typically an end portion thereof, in the example a rectangular gas tank 82 as illustrated in both Figures 3 and 6.

[0031] The first recess 72 is preferably implemented at the time of manufacturing the vehicle 10, by shaping the first portion 72 of the outer bottom surface 70 of the floor 50 into a configuration wherein, regardless of the embodiment, a concave shape is imparted to the first recess 72 relative to the enclosure 42, i.e. the first portion intrudes within the volume of the enclosure, rather than projects underneath it.

[0032] The shaped floor 50 can then be positioned and secured, by welding, riveting or a similar securing technique, relative to one or more rear section(s) 90 of the vehicle chassis, so that the first recess 72 is peripherally bounded by the peripheral section(s) 90, as illustrated in Figure 5 of the chassis. The first propellant tank 80 can then be secured within the first recessed portion 72. [0033] The shaping operation may for instance be embodied through pressing, punching or a similar metal-forming technique, the material plate constituting the floor 50 of the enclosure 42, prior to mounting same within the vehicle chassis. Given the specific example of the toroidal LPG tank 80, the first recess 72 is given the shape of an elliptical cylinder, oriented substantially transverse to a plane defined by the outer bottom surface 70. The skilled person may consider other shapes for the first recess 72, according to other types and/or shapes of propellant tanks, for example a rectangular prism oriented parallel to the plane defined by the outer bottom surface 70, for accommodating a cylindrical tank 80 as illustrated in Figure 6. [0034] Reverting to the possibility of fuelling the vehicle engine 32 with a gas or diesel propellant requiring a respective second tank 82, and thus the implementation of a second recess 74 in the outer bottom surface 70, then this second recess 74 may be implemented likewise at the time of manufacturing the vehicle 10, by shaping the second portion 74 of the outer bottom surface 70 of the floor 50 complementarily with the shape of the second fuel tank or an end portion thereof proximate the rear section 40, as illustrated in Figure 6.

[0035] Accordingly, the invention disclosed herein provides a structure for the rear section of a vehicle, together with a method of manufacturing a vehicle with same, embodiments of which all generally increase the operational safety of fuelling a vehicle from a liquid petroleum gas tank.

[0036] In the specification the terms "comprise, comprises, comprised and comprising" or any variation thereof and the terms include, includes, included and including" or any variation thereof are considered to be totally interchangeable and they should all be afforded the widest possible interpretation and vice versa. The invention is not limited to the embodiments hereinbefore described but may be varied in both construction and detail. ith the method of claim 9 or 10, or with the vehicle according to claim 11 or 12.

Claims

1. A structure for the rear section of a vehicle, comprising a chassis having a plurality of peripheral sections and an enclosure accessible through a latched body panel of the vehicle, wherein the enclosure includes inner and outer bottom surfaces in opposition to each other and jointly defining a firewall ; and wherein first and second portions of the outer bottom surface respectively include first and second recesses, with each recess dimensioned to accommodate a respective propellant tank ; characterised in that at least the first portion is bounded by one or more of the peripheral section(s) and located between a rearmost of the one or more peripheral section(s) of the chassis and a rearmost axle of the vehicle ; and a depth of the first recess relative to the outer bottom surface is less than a maximum height of the one or more bounding peripheral section(s) relative to a surface on which the vehicle rests or travels.

2. A structure according to claim 1 , wherein the outer bottom surface is substantially parallel to the inner bottom surface, and wherein the inner bottom surface is concave relative to the enclosure.

3. A structure according to claim 1 or 2, wherein the first propellant tank is a liquefied petroleum gas (‘LPG’) tank.

4. A structure according to any of claim 1 to 3, wherein the first recess is shaped as an elliptical cylinder, oriented transverse to a plane defined by the outer bottom surface.

5. A structure according to claim 4, wherein the first propellant tank is substantially toroidal.

6. A structure according to any of claim 1 to 3, wherein the first recess is shaped as a rectangular prism, oriented parallel to a plane defined by the outer bottom surface.

7. A structure according to claim 6, wherein the first propellant tank is substantially cylindrical.

8. A structure according to any of claim 1 to 7, further comprising a removable panel adapted to cover the first recess and the first propellant tank therein.

9. A method of manufacturing a vehicle, comprising steps of providing a chassis for the vehicle, the chassis having one or more peripheral section(s) ; providing a floor for a rear section of the vehicle, the floor having inner and outer bottom surfaces opposed to each other and made of a material impervious to fire; shaping first and second portions of the outer bottom surface respectively with first and second recesses, with each recess dimensioned to accommodate a respective propellant tank ; locating the floor relative to the chassis, so that at least the first recess is bounded by one or more of the peripheral section(s), located between a rearmost of the one or more peripheral chassis section(s) and a rearmost axle of the vehicle, and less than a maximum height of the bounding peripheral chassis section(s) relative to a surface on which the vehicle rests or travels ; and securing the first propellant tank in the first recess.

10. A method according to claim 9, wherein the outer bottom surface is substantially parallel to the inner bottom surface and wherein the step of shaping further comprises shaping the inner bottom surface to be concave relative to the enclosure.

11. A vehicle comprising a structure according to any of claims 1 to 8, or manufactured according to the method of claim 9 or 10.

12. A vehicle according to claim 11 , comprising a liquefied petroleum gas tank located within the first or the second recessed portion.

13. A propellant tank for use with the structure according to any of claims 1 to 8, or with the method of claim 9 or 10, or with the vehicle according to claim 11 or 12.