CA2323815C - Engineered roof top storage unit for cng cylinders for motor vehicles - Google Patents

Abstract

A storage unit for compressed natural gas cylinders for mounting on the rooftop of flat roofed vehicles, is designed for safety, reduced drag and lightweight. CNG
cylinders are protected against impact and rollover by a cage made of rollover bars. The assembly is covered with a cowling aerodynamically designed to reduce drag on the vehicle.
The design also facilitates fitment on vans and minivans of different makes and models by having (a) Adjustable flap and slat (on the trailing and leading edges of the cowling respectively), which could be rotated about horizontal axes, wherein flap and slat are aerodynamic devices on the leading and trailing edges of the body, respectively, to prevent flow separation around an aerodynamic object by suitably directing the flow of air around it. (b) Middle portion of the cowl, which could be adjusted for length and position on fixed tracks.

Description

TITLE OF THE INVENTION:
Engineered Roof Top Storage Unit for CNG Cylinders for Vans and Minivans.
BACKGROUND OF THE INVENTION
Field Of Invention:
This invention relates to having a rooftop storage unit for Compressed Natural Gas (CNG) Cylinders for motor vehicles running on CNG, typically vans and minivans. The scope of this invention applies exclusively to vehicle that are of the generic type of van and minivan. In the following text the use of the term van implies modern vans manufactured in 1996 or later. The invention also applies to minivans manufactured in 1996 or later and is designed to capture both the new and after sale market of existing vans and minivans. The rooftop CNG storage unit or kit can be installed on a new or used vehicle. Hence, the abbreviation, CANI1KI, used henceforth stands for Canadian Natural Gas Upgrade Kit and represent the embodiment of this invention.
The components of CANUKI only apply to the rooftop of vans and minivans and do not apply to other locations or configurations such as found in trailers, trucks and under carriages of motor vehicles that are used for the storage of CNG cylinders.
Background Discussion of Prior Art:
With the present concerns about increasing levels of pollutants in the environment, the motivation to use environmentally friendly alternative fuels, such as CNG, in automotive vehicles has increased. Although the technology for use of CNG in vehicles already exists, its full commercial potential has still not been exploited in the US
and Canada.
Two of the reasons cited by the users are poor CNG infrastructure (too few refueling stations) and poor range provided by the CNG fuel storage systems currently in use in vehicles. These factors are related. A higher range could obviate the need for a large number of refueling stations placed in close proximity and reduce the inconvenience of refueling frequency. CANUKI was designed to extend the range of vans and minivans by at least 400 Km.

Available prior art inventions concentrated on mounting the cylinders inside the vehicles or the under them. U.S. Patent No.5,794,979 (Method and Structure for mounting a fuel tank) provides an effective method for mounting the CNG cylinders in the trunk of a vehicle. This causes two problems. Storage space of the trunk gets reduced.
Due to space requirements, not more than 2 to 3 cylinders are possible to be fitted. There do also exist systems, which allow mounting of CNG cylinders under the chassis of the vehicles. This again places restrictions on the types of vehicles with high ground clearance that can allow the placement of cylinders in such a manner.
Patent No. 5,370,418 (Integrated chassis and compressed gas fuel system of an automotive vehicle) is an invention that in theory can solve the problem of small range of vehicles but it requires total modification of the chassis of the vehicle.
This takes away any scope for after market conversion of vehicles for higher range.
Canadian Patent 2287386 Scott et al This is a typical example of a patent that applies to generically different type of vehicle, typically a City Bus. It does not include a reference to a cowl and does not require a roll bar that is essential for a van or minivan U.K. Patent 2158791 Mackay discloses Aerodynamic protective cover for a Luggage rack.
A careful distinction should be made between the general use of the term "aerodynamic"
and the professional engineering use of this term. Unless substantiated with calculation or experiment, this term remains a loose adjective that applies to any external smooth shape (i.e. without abrupt changes of curvature) of an object moving through air.
For the present invention, the term aerodynamically shaped external cowl refers to an engineered precise shape that was arrived at through numerical calculations with the sole purpose of reducing the overall drag of the vehicle. Volume I discusses this aerodynamic analysis.
The non-dimensional co-ordinates of the cowl are unique and scale with the representative length of the van or minivan. These co-ordinates (that determine the shape of the cowl) were determined through a repetitive analysis of trial shapes (see Volume 1 ) are given by a shape that displayed the best flow characteristics, low drag and delayed flow separation.
Patent # 1160455, German, 2nd Jan, 1964/ US Patent # 1523252, 1661001, 2326176, 2331504 and 2677938 Shows support system for transportation of CNG cylinders in railway cars US Patent # 5685350, Chowdhury, "Method and Apparatus for the Transportation, Storing and Delivering Dangerous Chemicals"

This patent shows long cylinders (6) mounted on articulated truck transport.
US Patent 4060174, Helmut Gerhard, Nov. 29, 1977 Self Contained Double-Tubular Transport Container.
Shows Twin tubular containers for transporting "gas under high pressure". This either a railway car or articulate truck support system.
US Patent 3479043 Gas Transportation Apparatus, B. Piehl, Nov 1969 Gas Transportation Apparatus for an articulated truck carrier.
US Patent 5,370418, Nicholas Pugh, Dec. 1994 Integrated Chassis and compressed gas fuel system of an automotive vehicle Shows chassis mounted tanks for sports vehicle.
US Patent 5040933, Lee et al, Aug 1991 Trailer for cylindrical container modules Trailer based support system for CNG Cylinders UK Patent 532208 Alexander T. A. Dear A Improved Gas Storage System Features a CNG cylinders storage system mounted on a two wheeled Towing vehicle 115 Patent 58794979, T. Kasuga et al Method and structure of mounting a fuel tank Features two CGN cylinders mounted inside a sedan's trunk.
US Patent 3861572, Norris et al, Jan 1975 Carrier Mountable on roof rack of a Car This Patent Features a carrier mounted on a automobile roof. It patent has not been design to carry CNG cylinders.
US Patent 6056176, Aftanas et al, May 2000 Vehicle Article carrier having clamping Cross bar This patent was brought up through the search processes presumably due to the term "cross bar". The utility and design of this apparatus differs fundamentally from CANUKI. In this patent the cross bar is been designed to hold articles on to the carrier and not CNG cylinders US Patent 60065915, J.W. Ruehl Tank Storage apparatus This Patent is similar in intent to patent listed above and in particular not designed to roof installation and mounting of CNG cylinders.
It is the applicant's contention that the subject matter of claims specified later could not logically be arrived at by a person skilled in the art or science of the subject matter by reading the above Patents.

While a large number of patents exist on rooftop carriers and article carriers, none has been engineered to carry compressed natural gas cylinders, which requires special design features for safety and light weight. Moreover, none has features to adapt to vans and minivans of different makes and models by adjusting slat and flap' aerodynamically designed to suit individual vehicles.
In accordance to Section 29 of the Patent Rules, the applicant wishes to declare that the present invention, as specified in this patent application, was first described in the United States of America Patent Application Number, 09/692,103 filed on 20t" October 2000.
SUMMARY OF THE INVENTION:
In accordance with the present invention called CANUKI (Canadian Natural Gas Upgrade Kit), Compressed Natural Gas Cylinders (Commercial off the shelf) can be mounted on the rooftop of flat roofed vehicles, typically vans and minivans.
CNG
cylinders are protected against impact and rollover by a cage made of rollover bars called 'Roll cage'. The assembly is covered with a cowl designed aerodynamically to reduce drag on the vehicle. The design of CANUKI also facilitates fitment on vans and minivans of different makes and models due to, (a) An adjustable 'slat' and 'flap' on the leading and trailing edges of the cowl respectively. These components could be rotated about a horizontal axes, wherein the slat and flap are aerodynamic devices on the leading and trailing edges of the cowl, respectively, to prevent flow separation around the cowl by suitably directing the flow of air around it.
(b) Middle portion of the cowl that could be adjusted for length and position.
~ Slat and flap are aerodynamic devices to prevent flow separation around an aerodynamic object by suitably directing the flow of air around it.

Objects and Advantages:
Objects and advantages of the present invention are as follows:
a) To provide means of mounting CNG (Compressed Natural Gas) cylinders on rooftop, without compromising safety.
b) To keep the drag low with an aerodynamically designed cowl.
c) To allow mounting of four or more CNG cylinders so that the vehicles could have a higher range with CNG (a range of more than 400kms as compared to typically 200kms at present).
d) To allow inner space of vehicles to be fully utilized for storage and transportation of goods and materials.
e) To provide a single system that could fit on vans and minivans of most makes or models.
BRIEF DESCRIPTION OF THE DRAWINGS:
The drawings have been made specifically for General Motors Corporation's Chevy Astro Van and DiamlerChrysler's Dodge Grand Caravan but the basic concept of CANUKI is transferable to vans and minivans of other makes and models. The dimensions in the drawings are typically for the two makes mentioned earlier and may be different for other makes and models.
Fig. 1 & 2: These are general configuration drawings for vans and minivans respectively.
The three views show how CANUKI will be mounted on a van or minivan. It also shows how the CNG cylinders will be positioned in the housing.
Fig. 3: Drawing of cylinder bracket (supplied by cylinder manufacturers).
Fig. 4A Cross-Member, Cargo Track, Mount Interface and Roof Attachment Fig. 4B Cross-Member and Mount Interface Attachment Detail Fig. 4C Cross-member and Cargo Track Attachment Fig. 5: Drawing of Cargo Track main structural mount assembly.
Fig. SA Exploded Side View of internal attachment for Roll Cage Main Mount Fig. SB Exploded Front View of Fig. SA (looking front to rear of vehicle) Fig. SC Side View of internal attachment for Roll Cage Main Mount Fig. SD Plan View of Roll Cage Main Mount on Roof Top Fig. SE Section through Roll Cage Mount on Roof Top (one of four) Fig. 6A Roll Cage Configuration - Side Elevation Fig. 6B Roll Cage Configuration - Plan View Fig. 6C Roll Cage Configuration - Front View Fig. 7A CNG Cylinders Mounted on Cargo Track - Side View Fig. 7B CNG Cylinders Mounted on Cargo Track - Plan View Fig. 7C CNG Cylinders Mounted on Cargo Track - Front View Fig. 8: Plan View of Cowl Fig. 9A Plan View of Standard cowl Fig 9B Plan View of Extended cowl Fig.lOA Section Through Slat Fig.l OB Slat of cowl.
Fig.l l .A Flap of cowl.
Fig. 11 B Section Through Flap Fig 12. Alternative configuration I for CNG cylinders (Plan View) Fig 13. Alternative configuration II for CNG cylinders (Plan View) Reference Numerals in drawings:
Specific Name General NamelDescription la Van Flat roofed van 1 b Minivan Low curvature roofed minivan 2. Compressed Natural Gas (CNG)CNG Cylinder Cylinder 2a. Cylinder Bracket Means of securing the cylinders to the a cargo track cross-member 3. Cowl Cover for the cylinders 3a. Right Cowl Fairing2 Curved surface of cowl on the right 3b. Left Cowl Fairing Curved surface of cowl on the left z Fairing is a member or structure whose primary function is to produce a smooth outline and to reduce drag (as on an airplane) 4. Slat Leading surface slat of the cowl 4a Flexcore Material Flexible Flexcore material 4b Rotated Slat Slat shown in maximum clockwise rotation ( 10 degrees) 4c Slat Rotation Point 4d Slat Attachment Flange 5. Flap Trailing surface flap of the cowl Sa Flap Rotation Point Sb Rotated Flap Flap shown in maximum anti-clockwise rotation (10 degrees) Sc Attachment point for Translating Arm 6. Roll Cage Means of protecting the CNG cylinders from frontal or roll over impact damage.

7. Roll Cage Main StructuralMeans of mounting the Roll cage Mount on the rooftop of van/minivan 8. Center Mount Additional support for the cross members.

9. Molded Angle Means of holding the fairing in place and sealing it with the roof of the van 10. Bolts M 12 Means of securing the cylinder brackets.

11. Spacer Means to prevent interference between cylinders.

12. Mount Interface Means of providing an interface between the roof and cargo seat track 13. Cargo Seat Track Means of providing an adjustable surface for cross members.

14. Anchor Means of securing cross-members to the cargo seat track 15. Anchor locking mechanismMeans of locking the anchor in place.

l6. Bottom Washer ---17. Cross-member Means of providing support to the cylinders.

18. Neoprene Washer Absords vibration and reduces noise 19. Oversized Washer ---20. '/2 inch Nut ---21. '/Z inch Grade 5 Bolt ---22. '/2 inch grade 5 Nut ---23. Backing Plate Means of providing a support to the rooftop 24. Bottom Rubber Gasket ---25a Top Rubber Gasket 25b Vehicle Roof Top ---26. Countersunk Screw ---27. Pressure Relief Valve Means of releasing excess pressure in the cylinders.

28. Pressure Relief Tube Vent for gas.

29 beading Edge of Cowl Cowl un-extended Extension 30 Leading edge of Cowl Cowl fully extended Extension DESCRIPTION OF THE PREFERRED EMBOD1MENT:
A preferred embodiment of the invention, referred to CANUKI (Canadian Natural C'ras Upgrade Kit), is shown in figures 1 and 2. The essential parts of the invention are:
a) The mounting of the CNG cylinders on the rooftop of vans and minivans.
b) Aerodynamically designed cowl or cover for the housing.
c) Adjustable length of the middle portion of cowl d) Adjustable slat and flap of the cowl.
The invention is to be used for vans and minivans running on Compressed Natural Gas (CNG). The figures and dimensions are typical of Astro van (5 cylinders configuration) and Dodge Grand Caravan (4 cylinders configuration), but the invention can also be used for any flat top van or low curvature roofed minivan. Figures 1 A, B, C and Figures 2 A, B, and C are explanatory views showing the general mounting configuration of light weight Commercial off the shelve, COTS CNG cylinders 2, typically made of composite materials.
CANUKI essentially consists of a Roll Cage 6 and cross-members 17, which house CNG
cylinders and an aerodynamically designed cowl 3. Roll Cage and cross-members are made of composite material for light weight. Roll Cage is mounted on the rooftop of van through main structural mounts 7. CNG cylinders are mounted on the cross-members with cylinder brackets 2a. Right cowl fairing 3a and left cowl fairing 3b are designed to blend in with the sides of the vehicle. Fairings are held in place with a molded angle 9, which is contoured as per the shape of the vehicle top.
Fig 3 gives the drawing of cylinder bracket 2a and shows how the cylinders are mounted on the cross members. Nuts 10 are used to mount the brackets on the cross-members 17 and spacer 11 is used to prevent interference between cylinders.
Fig 4 A, B, C and Fig 5 A, B and C show how the cross-members 17 are mounted on the vehicles through cargo seat tracks 13. Cargo seat track is mounted on the mount interface 12 using countersunk screws 26. The cross-members are then anchored to the cargo seat track with the help of anchor 14, anchor locking mechanism 15, washers 16, 18, 19 and nut 20. Cargo seat track and anchor assemblies are COTS. The mount interface 12 is mounted on the rooftop using a backing plate 23 and rubber gaskets 24 and 25a on either sides of the van roof, 25b, with bolts 21 and nuts 22. Additional support is provided to the cargo seat track 13 by center mounts 8.
Figures 6A, B and C show Roll Cage 6 configuration and drawing of the main structural mounts 7. Main structural mounts, which are essentially U-shaped brackets, are bolted to the rooftop along with the mount interface 12. Roll Cage tubing is preferably made of Chromally 4130 for better strength and low weight characteristics. The main purpose of the Roll Cage is to protect the CNG cylinders from damage in case the van/
minivan rolls over in an accident.

Figures 7 A, B and C provide a view of the all structural elements that secure the cylinders to the roof. These consist of the cylinder brackets, 2a, that fasten the cylinders to the cross members 17. The cross members are attached to the cargo track 13.
The cargo tracks are in turn attached to the roof by four end mounts 7, and two center mounts 8. Collectively the cross members, brackets, cargo tracks and mounts will be referred to as the Cradle. The cradle retains and secures the CNG cylinders to the roof top. The cylinders have pressure relief valve 27 and pressure relief tube 28 to release gas in case of over-pressurization (a feature of commercial-off the-shelf high pressure gas cylinders).
Fig 8 gives a view of the cowl configuration. The cage 6 (see Fig. 6B) is then covered with a cowl 3, which is held in place on the rooftop of van/ minivan with the help of molded angle fitted to the rooftop. The center section of the cowl can be moved longitudinally as required by an amount governed by the length of the van/
minivan. Fig.
9A shows the standard configuration typically for a minivan with 29, the forward edge of the extendible cowl. Fig. 9 B shows the extended cowl with 30, the forward edge of the extended Cowl.
A portion of slat 4 and the flap 5 of the cowl can rotate about a horizontal axes or pivot.
This ensures continuity of curvature from rooftop to cowl and cowl to rooftop at the leading and trailing edges of the cowl respectively (Fig.lO A, B & Fig.l l A
and B).
Having an adjustable center section, slat and flap of the cowl, gives CANUKI
the flexibility to be fitted on vans or minivans of most makes or models, thus considerably reducing manufacturing costs. Various joints can either be sealed using a permanent seal or a flexible seal made of weather resistant rubber. The option of making customized cowls for mass orders still remains with the manufacturer, when savings on costs with fixed slats and flaps on large production runs, for a particular model vehicle, is possible.
Thus there are four options. The first option is to have a configuration that fits most vans or minivans, where middle portion of the cowl, slat and flap are adjustable.
Second option typically for five cylinders configuration where the middle portion and flap are fixed and designed specially for long body vans but the slat is adjustable to suit front-end profiles of different vans/ minivans. A third option could be for a four cylinder configuration where the middle portion and flap are fixed and designed specially for short body vans but slat is adjustable to suit front-end profiles of different vans/
minivans. A
fourth option allows the manufacturer to build customized cowls where all the components are fixed and designed specifically for a particular make and model of van/minivan.
Gas filling line and supply line to the carburetor will be taken through a hole in the roof through the doorpost to the bottom and along the chassis to a convenient location under the bonnet.

Description - Alternative Embodiment:
As alternative embodiments, the CNG cylinders can be place longitudinally on the rooftop of the van as is shown in Figs. 12 and 13.
Advantages:
From the above, advantages of CANUKI are:
a. This invention offers a system that allows CNG cylinders to be carried on top of the rooftop of vans and minivans and thus leaving the cabin room unaffected b. This allows a higher range of more than 400kms with CNG before a refill may be necessary, making the use of Compressed Natural Gas more attractive.
c. The adjustable design offers flexibility for the manufacturer who can keep costs low by making a one-kit-fits-all type of configuration to suit any van or minivan.
Alternatively if required a rigid model customized as per requirement, can be manufactured for large production runs OPERATION OF THE PREFERRED EMBODIMENT
The preferred embodiment of the invention is used in conjunction with the conventional dual fuel (gasoline/ CNG) systems or dedicated CNG systems used in vehicles.
It can be mounted on the rooftop of vans and minivans with the means described in the section above. The salient features of the invention are aerodynamically designed cowl (3) that minimizes the drag on the vehicle, Roll cage (6) that protects the cylinders from damage in case of a vehicle meeting with an accident and rolling over, and adjustable slat (4) and flap (5) that can be adjusted to suit the profile of the van or the minivan on which the invention will be mounted on. The cylinders are mounted on the rooftop of vans and minivans and connected to the engine by high-pressure tubes and valves going though the door pillar of the vehicle.

CONCLUSION, RAMIFICATIONS AND SCOPE:
Engineered roof top storage unit for CNG Cylinders for motor vehicles is an invention that provides for mounting of CNG cylinders on the rooftops of van and minivans. The major advantage of this is to enable the vehicle to travel longer on CNG
before refueling is necessary. The inside of the vehicle is still available for storage and transportation of other goods and materials. The aerodynamic design ensures low drag on the vehicle. The inclusion of roll bar ensures safety against accidents.
This invention encourages the use of Natural Gas, which is a more environmentally friendly fuel than gasoline and is KYOTO compliant due to the reduction in the volume carbon-dioxide discharged for a calorific equivalent amount of fuel.
Although the invention has been described in connection with the preferred embodiment, it should understood that various modifications, additions and alterations may be made to the invention by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims (2)

1. A storage device for compressed natural gas cylinders engineered for mounting on a rooftop of a van or a minivan comprising of, (a) a roll cage of rigid material, attached to said rooftop, of sufficient strength to withstand impact of a rollover of said van or said minivan whereby said roll cage protects said compressed natural gas cylinders from structural damage, (b) a cradle as means to contain and secure said natural gas cylinders on said rooftop comprising of a plurality of cross members, cargo tracks and interface mounts, wherein, i) said cross members are used as means to attach said cylinders to said cargo tracks, ii) said interface mounts are used as a means to attach said cargo tracks to said rooftop, (c) a cowl that covers the roll cage and the cradle, whereby protecting it from wind, rain and sunlight comprising of a sheet metal material of continuous surface curvature.

2. The storage device of claim 1 wherein said cowl is a means for reducing the aerodynamic drag of said roll cage and said cradle comprises of, a) a slat on a leading edge of said cowl, wherein said slat can rotate about a horizontal axis as a means to ensure continuity of surface curvature from said rooftop to said cowl, b) a flap on a trailing edge of said cowl, wherein said flap can rotate about a horizontal axis as a means to ensure continuity of surface curvature from said cowl to said rooftop, c) a center segment as a means for adjusting the length of said cowl, wherein said center segment lengthens said cowl to match a longer said rooftop.