WO1995006569A1 - Systeme de suspension pour vehicule a energie solaire - Google Patents

Systeme de suspension pour vehicule a energie solaire Download PDF

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Publication number
WO1995006569A1
WO1995006569A1 PCT/AU1994/000510 AU9400510W WO9506569A1 WO 1995006569 A1 WO1995006569 A1 WO 1995006569A1 AU 9400510 W AU9400510 W AU 9400510W WO 9506569 A1 WO9506569 A1 WO 9506569A1
Authority
WO
WIPO (PCT)
Prior art keywords
cells
solar panel
frame
solar
suspension system
Prior art date
Application number
PCT/AU1994/000510
Other languages
English (en)
Inventor
Arthur Baddeley
John Burns
Bradley Cadwallader
Ian Cole
William Faull
Michael Hofmann
Clive Humphris
Charles Lakey
Gregory Locock
Grant Lumsden
John Mole
Rodney Phillips
Robert Powell
Anthony Vriens
Geoffrey Wiffen
Original Assignee
Aurora Vehicles Association Incorporated
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Aurora Vehicles Association Incorporated filed Critical Aurora Vehicles Association Incorporated
Priority to AU76059/94A priority Critical patent/AU7605994A/en
Publication of WO1995006569A1 publication Critical patent/WO1995006569A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D21/00—Understructures, i.e. chassis frame on which a vehicle body may be mounted
    • B62D21/18—Understructures, i.e. chassis frame on which a vehicle body may be mounted characterised by the vehicle type and not provided for in groups B62D21/02 - B62D21/17
    • B62D21/183—Understructures, i.e. chassis frame on which a vehicle body may be mounted characterised by the vehicle type and not provided for in groups B62D21/02 - B62D21/17 specially adapted for sports vehicles, e.g. race, dune buggies, go-karts
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G1/00—Suspensions with rigid connection between axle and frame
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D31/00—Superstructures for passenger vehicles
    • B62D31/003—Superstructures for passenger vehicles compact cars, e.g. city cars
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D61/00—Motor vehicles or trailers, characterised by the arrangement or number of wheels, not otherwise provided for, e.g. four wheels in diamond pattern
    • B62D61/06—Motor vehicles or trailers, characterised by the arrangement or number of wheels, not otherwise provided for, e.g. four wheels in diamond pattern with only three wheels
    • B62D61/08—Motor vehicles or trailers, characterised by the arrangement or number of wheels, not otherwise provided for, e.g. four wheels in diamond pattern with only three wheels with single front wheel

Definitions

  • the invention relates to the design of low energy consumption vehicles, such as solar powered vehicles and in one aspect for a suspension system particularly suited to conveyances of this kind.
  • the present invention also relates to solar cell arrays for curved surfaces and to flat or curved solar panel structures incorporating solar cell arrays.
  • Another aspect of the invention relates to electrical battery source configurations and methods of controlling that battery source for driving a single load.
  • the term battery is used herein to refer to any device capable of storing electrical energy including capacitors.
  • the design of the vehicle wheels and suspension system in a low energy consumption vehicle is extremely important, particularly with regard to rolling resistance, ride quality and handling.
  • requirement (b) calls for the suspension systems to be soft or have high compliances
  • requirement (d) calls for systems to have low compliances.
  • good suspension design involves allowing each wheel a controlled amount of compliance in each of the several different directions of movement. It is possible to keep compliances low in the directions important for the achievement of good steering and handling, while allowing high compliances in the directions critical to good rides. It is not possible, however, to fully separate and thereby reconcile the conflicting requirements.
  • Total compliances in suspension systems are made up of those individual compliances due to the action of the primary suspension components, such as springs and dampers, and those due to others such as rubber isolators.
  • the achievements of requirement (b) necessitates consideration of low frequency disturbances, which are involved in determining the ride of the vehicle, and high frequency disturbances, which contribute to what is referred to as road noise.
  • a problem with the majority of prior art suspension systems is that they rely at least in part on the rigidity of the vehicle chassis or body structure to which the suspension is connected, to ensure that the preferred geometrical relationship between the respective wheels and the wheels and the body is maintained. This is extremely difficult to achieve when a simultaneous objective is that of minimising the weight of the vehicle body structure and is almost impossible to achieve in practise with most light weight body structures that have a high degree of inherent flexibility.
  • the solar arrays of most applications use a configuration of cells in which the solar cells are spaced from each other to avoid any cells touching.
  • This layout gives a maximum usage of each of the cell faces thereby achieving a maximum power per unit mass of cells or per unit cost of cells.
  • the solar cells are laid out so that they can be serially connected electrically in strings.
  • the voltages of each of the cells are added to give the string voltage.
  • stringing of the cells makes the electrical power of the array more usable. Identification of the voltage at which the array power is needed and therefore the number of cells required to make up the string, is also an important decision in the design of the solar array.
  • a balanced string of photovoltaic cells is one in which all cells are operating at the same voltage. Strings of cells are imbalanced when the cells experience different levels of insolation (as in the case, for example, when some are shaded) or when the cells in the string are sited on different inclinations such that the angle of incidence of the suns radiation varies. Both of these situations cause the current/voltage curves for individual cells in the string to differ.
  • race regulations define a single right rectangular parallelepiped as the only volume in which the cells may be placed. As a result of this, the power per unit area of the array also becomes critically important.
  • This lamination process consists of positioning the cell array between two flexible sheets of encapsulent material, such as polyvinyl fluoride. The resulting sandwich is located on a suitable backing or substrate material and heat and pressure is applied to simultaneously electrically encapsulate the cells and bond the array to the substrate.
  • the aerodynamics of a solar electric car are very important, especially if the vehicle is to be used for racing.
  • aerodynamic considerations dictate that the vehicle body and preferably the associated solar array must in general be curved rather than flat and further that the surface of the array must be as smooth as possible to minimise drag.
  • race regulations and rules for Solar electric powered race vehicles set constraints on the maximum capacity and rating of the batteries to be used. As there are a number of different types of available battery having differing operating characteristics, the selection of one of these available battery types is nearly always a compromise.
  • a suspension system for a light weight vehicle comprising: an unsprung frame adapted to receive and support at least three wheels for rotation about respective parallel axes by means of substantially undeformable support members connectable to the frame, wherein the frame is substantially rigid between at least two of said axes, the system also including dampable resilient means adapted to cooperate with the frame to support and isolate a vehicle body therefrom.
  • the entire unsprung frame is substantially rigid and is preferably of a generally triangular configuration adapted to support one wheel at or adjacent each verte .
  • the frame is configured to support two spaced apart rear wheels having aligned axes and a front centrally located wheel that is connected with the frame by means of a rotatably mounted steering post.
  • a single fixed rear wheel is provided with two front steering wheels having axially aligned but spaced apart axes of rotation.
  • the resilient means are in the form of coil springs, which are separately damped with hydraulic dampers in the usual manner.
  • one spring is mounted on the frame adjacent each of the two spaced apart axially aligned rear wheels and, for convenience, two springs mounted on the frame, one either side of the front wheel.
  • the unsprung frame may comprise coupled separate fore and aft rigid subframes, each subfra e being adapted to support two or more wheel axes, the rigid subframes being adapted for interconnection in a manner whereby there is provided at least one degree of freedom of motion therebetween.
  • the two subframes are coupled in a manner that allows relative rotation about a fore to aft longitudinal axis that extends transversely to the wheel axes and which is preferably generally parallel to the ground surface, that is to the plane containing the wheel axes. It is further preferred that the axis of rotation would have a virtual location at or closely adjacent ground level to minimise bump steer.
  • the coupling for providing one or more degrees of freedom of motion between the rigid subframes has associated therewith resilient and/or damping means for controlling that freedom of motion.
  • pivotably interconnected subframe construction provides a means by which the axles of the four wheels need not maintain fixed relative positions, so that each of the four wheels may maintain contact with the road surface over a reasonable range of road profiles.
  • the freedom of motion in the preferred form to rotation about a longitudinal axis, the fore to aft alignment of the wheels is maintained. Motion in the yaw degree of freedom is generally prevented.
  • the suspension systems according to this first aspect of the invention gives superior performance because it gives almost complete differentiation between the forces and therefore compliances involved in the achievement of good ride and those involved in the achievement of good steering and handling.
  • Good handling and steering are achieved due to the fact that the wheels cannot move greatly relative to each other. Very high compliance can therefore be allowed between the frame and the body enabling good ride and reduced road noise.
  • the preferred three-wheeled rigid unsprung triangle system it is possible to design the compliances between the triangle and the body such that the different fundamental motions, or degrees of freedom of the body can be handled separately. For example, it is possible to allow very low compliance in the yaw degree of freedom.
  • a simple vertical moving suspension system is most likely to be used for the single wheeled end of the car.
  • Use of such a system means that the centre of roll of the body of the car is at the tyre contact patch on the road surface. If the suspension system used at the two wheeled end of the car is not such that the roll centre is at a similar height, the handling of the car may be peculiar and unexpected. This would be due to the fact that the axis of roll and the longitudinal inertia axis of the body were not coincident or at least parallel. For short duration rolling of the body, motion is about the inertia axes, while longer duration rolling occurs about the roll axis. There is much greater flexibility in positioning the roll axis with the rigid unsprung triangle system.
  • the system also has the advantage in that build accuracy of the body is not critical for wheel alignment accuracy. It is therefore possible, in a mass production implementation of the system, to use lower cost body build techniques. Achievement of better wheel alignment may also be cheaper and easier due to the fact that it is determined by the triangle before it is fitted to the car. Assembly of the frame to the body should be relatively simple in production since there would not be high dimensional tolerances for the operation.
  • a solar cell array configuration for a non-flat surface comprising: a plurality of solar cells of similar size and shape that are each overlapped with one or more adjacent cells such that when viewed from a predetermined angle, the apparent uncovered area of each cell projected in that direction is substantially the same.
  • the selected predetermined angle is 90° to the general planar extent of the array.
  • this equates to viewing the panel from directly above. From a manufacturing view point, this also enables a simple rectangular arrangement of cells to be used.
  • the overlapped solar cells are electrically isolated from one another within the construction of the array, such that they can subsequently be serially connected electrically in strings.
  • the connections can be selectively varied to change, for example, the number of strings in the array, or the configuration of the cells making up a string, such that the matching of the cells can be varied or optimised as desired.
  • An advantage of configuring the cell array in accordance with the second aspect of the invention, particularly in regard to a solar powered electric racing vehicle to be constructed within the strict design parameters outlined above, is that it reduces virtually to zero the amount of the allowable cell area which is lost due to spacing gaps and thereby maximises the power per unit area.
  • the cell dimensions, desired spacing and array dimensions need not be related such that an integer number of cells fit within the length and width of the array. This is important because as a result of optimisation between the performance of the panel and aerodynamics of the vehicle as a whole, the array will most likely not be flat in shape and the true dimensions across the panel will therefore vary.
  • the problem of imbalance of the strings is also at least partly overcome by the laying of the cells such that the apparent uncovered area of each cell is equal when viewed from a particular angle.
  • a solar panel laminate structure comprising a layer of solar cells having a moulded layer of substantially optically transparent material having a smooth outer surface on the receiving surfaces of the cells and a layer of structurally supporting substrate on the rear side of the cells.
  • the transparent material layer may be vacuum formed or otherwise moulded from a suitable sheet material or alternatively formed from resin cured in a mould, or even a combination of both.
  • the resin is also reinforced with a substantially optically transparent material such as woven or unwoven fibreglass matting.
  • a solar panel laminate structure comprising: a layer of solar cells having a coating of substantially optically transparent reinforced resin on the receiving surfaces of the cells and a layer of structurally supporting substrate on the rear side of the cells.
  • a solar panel laminate structure comprising: a layer of solar cells having a coating of substantially optically transparent resin on the receiving surfaces of the cells and a layer of resin impregnated distance fabric adhered to the remote side of the cells.
  • Distance fabric as referred to herein, consists of two layers of woven fabric held at a constant spaced distance from each other by fibre webs or looped pile fibres of the same material.
  • the fabric comes in a variety of weave densities and spacing distances.
  • the preferred material is glass fibre fabric of 9mm thickness.
  • a carbon fibre or aramid distance fabric may also be suitable.
  • the coating resin is an epoxy resin, which is more preferably cured in a mould to provide a smooth outer surface to the structure.
  • the structure desirably further comprises an outer layer of ultraviolet absorbing acrylic coated to the epoxy layer. The acrylic may be sprayed onto the cured resin cell coating.
  • the laminate include a layer of reinforcing glass fabric embedded in the resin adjacent the receiving surfaces of the cells.
  • the glass fabric is preferably a woven bi-directional cloth.
  • the epoxy resin coating on the cell receiving surfaces is also formulated to minimise shrinkage.
  • the solar cells embedded in the structure are configured in accordance with the second aspect of the invention.
  • a method of making a solar panel comprising the steps of: applying to the inner surface of a mould a layer of substantially optically transparent resin; arranging a plurality of solar cells in the uncured resin with the receiving surfaces of the cells facing toward the mould surface; and adhering to the surfaces of the cells remote the mould surface a layer of resin impregnated distance cloth.
  • the method further comprises the step of embedding a layer of woven glass fabric into the resin adjacent the receiving surfaces of the cells.
  • air ducts are formed in the structure by connecting one or more manifolds in fluid flow communication with the interior of the distance fabric to direct cooling air to the cell array.
  • the manifolds are also positioned so as to also serve as stiffeners for the array.
  • the manifolds are desirably attached along a spine of the structure and extend to an apex or high point in the array.
  • heated air is directed through the interior chamber of the distance fabric to the uppermost manifold where it can be withdrawn by any suitable extraction means.
  • the extraction means can include fan means or more desirably NACA ducts formed in the vehicle body, preferably adjacent the wheel spats.
  • additional cooling air is drawn into the ducts through holes formed in the outer layer of the distance fabric that are disposed around the perimeter of the array.
  • the direction of air flow in the system is such that the tendency of the air to rise by convection due to its increasing temperature assists the air flow.
  • a major advantage of using the distance fabric as foreshadowed above is that the core of the fabric is permeable to air. Air can therefore be forced through the distance fabric to cool the array as described above, preventing damage to the cells due to high temperatures and thereby increasing the power output of the array.
  • Another advantage of using the distance fabric in the construction of a solar panel according to the third fourth, fifth and sixth aspects of the invention is that the distance fabric is able to conform to the irregularities of the rear of the cells after they have been placed in the mould, giving good adhesion and support to each of the cells.
  • an electrical battery source configuration for driving a single load, said configuration comprising: first and second inputs respectively for connection to first and second battery sources; an output for connection to said load; regulator means to define a respective current drain characteristic for each of said battery sources; and a controller including first means adjustable to control current flow to said load and second means responsive to said first means to selectively electrically connect said inputs with said load and provide said current flow in the load in accordance with the respective regulated current drain characteristics of each of said battery sources.
  • the controller includes two separate manually adjustable controllers respectively associated with said first and second sources.
  • the regulator means form part of each controller.
  • controller or controllers ensure that the load draws a substantially constant current flow from said first source and any required additional current from said second source.
  • the invention includes connecting similar battery types of differing capacity and/or connecting dissimilar battery types across a single load so as to be able to separately control the energy drawn from each source.
  • the battery sources may be rechargeable or non-rechargeable or include a mixture of both.
  • an easily rechargeable battery source such as lead acid batteries are used to accumulate incoming energy from, for example, a solar panel or by regeneration, which accumulated energy may subsequently be trickle fed to another rechargeable source which does not readily tolerate fast charging rates.
  • the electrical power source includes at least two separate battery sources, at least one of which is rechargeable with energy collected by a solar panel.
  • a first preferred combination is a mixture of rechargeable silver zinc batteries with rechargeable lead acid batteries.
  • Another preferred combination includes lead acid or silver zinc batteries in combination with a non-rechargeable light weight battery source such as lithium batteries.
  • a method of driving a single electrical load comprising the steps of: connecting first and second battery sources respectively to first and second inputs; attaching the load to an output; setting via regulating means the respective current drain characteristics for each battery source; connecting a controller intermediate the regulating means and output; and operating the controller via first means to adjust current flow to the load, the controller including second means responsive to the first means to selectively electrically connect said inputs with said load so as to provide said current flow in said load in accordance with the respective regulated current drain characteristics of each of said battery sources.
  • the controller may comprise two separate controllers.
  • the method includes using at least one rechargeable battery source, which source may, for example, be recharged from a solar panel or by regeneration.
  • the method uses two rechargeable battery sources each having different charge and discharge characteristics.
  • the method in this case includes the step of preferentially recharging the source that can tolerate high or variable charge rates to form an energy bank that can be used to recharge the other source that may only tolerate or charge efficiently at low and/or constant charge rates.
  • Figure 1 is a schematic perspective view of a curved solar vehicle panel surface and a rectangular cell alignment grid used to configure the solar cells in accordance with the second aspect of the invention
  • Figure 2 is a schematic longitudinal sectional view of the cell array taken on line 2-2 of Figure 1;
  • Figure 3 is a schematic transverse sectional view of the cell array taken on line 3-3 of Figure 1;
  • Figure 4 is a fragmented detailed plan view showing the marked overlapping cell arrangement adjacent the nose of the vehicle panel surface shown in Figure 1;
  • Figure 5 is a schematic sectional view through a preferred embodiment panel laminate structure made in accordance with the third, fourth, fifth and sixth aspects of the invention.
  • Figure 6 is a fragmented schematic transverse sectional view of the cell array, distance fabric and ducting configuration also taken on line 3-3 of Figure l;
  • Figure 7 is a schematic longitudinal sectional view also taken on line 2-2 of Figure 1 illustrating the ducting configuration and air flow;
  • Figure 8 is a schematic perspective view of a first embodiment three wheeled vehicle suspension system in accordance with the first aspect of the invention.
  • Figure 9 is a schematic plan view of the vehicle suspension system shown in Figure 8.
  • Figure 10 is a schematic side view of the vehicle suspension system shown in Figure 8.
  • Figure 11 is a schematic plan view of a second embodiment four wheeled vehicle suspension system in accordance with the first aspect of the invention.
  • Figure 12 is a schematic side view of the suspension system shown in Figure 11;
  • Figure 13 is a schematic plan view of a third embodiment four wheeled vehicle suspension system in accordance with the first aspect of the invention.
  • Figure 14 is a schematic side view of the suspension system shown in Figure 13;
  • Figure 15 is a schematic flow diagram for a basic electrical battery source configuration according to the invention.
  • Figure 16 is a schematic flow diagram for an electrical battery source configuration based on that shown in Figure 15 that is adapted for use with a solar powered vehicle.
  • FIG. 1 there is shown a schematic perspective view of a solar vehicle panel having a plurality of solar photovoltaic cells arranged in an overlapping configuration on the surface of the panel 1. It can be seen from the alignment of the true cell areas shown on the vehicle panel with the regular rectangular grid positioned directly above, that the apparent uncovered area of each cell when viewed from directly above the panel is substantially the same.
  • each of the overlapped solar cells 2 are electrically isolated from one another within the structure of the array by means, for example, of PVC tape insulator 3 as illustrated in Figure 5.
  • Each of the cells 2 has two electrical connections 4 that are desirably pre-connected with tinned copper lead wires or tapes prior to laying the cell in the array. These connections can be gathered from the array in any convenient manner and either pre-wired or grouped to pass through an opening formed in the substrate material to permit subsequent changes to the string configurations.
  • the cells are each connected to a central microprocessor that is able to constantly measure the output of each cell and reconfigure the strings to achieve maximum output from the array under all conditions.
  • the preferred panel structure is shown schematically in Figure 5. It should be noted that other unillustrated embodiments of the panel structure according to the invention include variations that use substrates other than distance fabric with reinforced or unreinforced moulded or unmoulded resin coatings.
  • the preferred illustrated panel is formed of a laminate structure 1 including a layer of solar cells 2 having a coating of substantially optically transparent resin 5 on the receiving surfaces of the cells. A layer of resin impregnated distance fabric 6 is adhered to the remote side of the cells.
  • the preferred distance fabric is made by Vorwerk having a product designation of 13501 - type B.
  • the preferred resin is LC3600 Araldite and Hardener produced by Ciba Geigy.
  • the preferred coating resin 5 is an epoxy resin which has desirably been formulated to have a good optical clarity and to minimise shrinkage.
  • a suitable epoxy resin for this purpose is available from Ciba Geigy and comprises a special formulation including Araldite, a flexibiliser and a hardener.
  • an ultraviolet absorbing acrylic top coating 7 covers the coating resin or epoxy 5.
  • a smooth surface is achieved in the preferred embodiment by constructing the panel in a mould (not shown) which has a correspondingly smooth moulding surface.
  • the panel 1 illustrated in Figure 5 which incorporates an overlapped cell configuration in accordance with the first aspect of the invention, is constructed as follows.
  • a female mould (not shown) is positioned open side upwards such that the general planar extent of the panel is substantially horizontal.
  • a rigid rectangular frame is then positioned directly above the mould, the frame having means to accurately define a regular grid of the type illustrated in Figure 1. In one form this is achieved by providing two transversely supported beams which are each moved along respective tracks.
  • the frame also includes vertical guide means, which may for example be mechanical and/or optical, such that each grid location can be projected down to the mould surface to guide the alignment of each overlapping cell 2.
  • a layer of adhesive quality epoxy resin is then spread over the mould surface within a controlled humidity environment.
  • the solar cells 2 are each individually wetted with resin and carefully positioned in the uncured epoxy. Each cell is overlapped in the manner previously described such that the true uncovered area of each cell aligns with the regular openings defined by the projected grid. strips of PVC tape insulator 3 are positioned between the overlapping cells 2 to electrically isolate each cell from the adjacent cells. The embedded cell structure is then allowed to cure.
  • the electrical connections to the cells are gathered in convenient bundles if desired, and the pre-cut distance cloth 6 is pierced at appropriate locations to allow subsequent access to each of the gathered connections.
  • the distance fabric is then wetted with resin in accordance with the manufacturers instructions and then placed over the cell array.
  • the distance fabric 6 is fairly pliable and readily conforms to the irregular surface of the overlapped cells 2.
  • the resulting structure is then cured, again within a controlled humidity environment, for a period of approximately 24 hours. It may then be desirable to break the structure from the mould prior to the above ambient temperature post curing operation. If it is necessary to increase the temperature to decrease the relative humidity, it is important that the temperature rise be applied slowly to prevent stress cracking due to the variations in the initial thermal expansion between the mould surface and the epoxy.
  • the resulting laminate structure is fairly rigid and basically self-supporting over the 2m x 4m preferred vehicle panel surface.
  • additional reinforcing structure can be added where desired to improve the local stiffness of the panel at load bearing locations.
  • a ducted cooling system is then provided in the panel by adhering a spinal manifold box 8 to the underside of the laminate 1 as shown in Figures 6, 7 and 8.
  • the inner surface of the distance cloth 6 is pierced such that the manifold is in air flow communication with the internal chamber of the distance cloth.
  • Air intake apertures 9 are also pierced in the outer skin of the distance cloth adjacent the lower edges of the panel.
  • the hot air is preferably drawn out of the uppermost portion of the manifold 8 by connection of the manifold to NACA ducts positioned preferably adjacent the rear wheel spats. Venting of the hot air then draws in additional cooling air. Flow of the cooling air to the spinal manifold is assisted by convection as the air heats up.
  • the outer layer is made from suitable substantially optically transparent sheeting which is vacuum formed or otherwise moulded to the required shape and fixed to the cells and substrate structure by any suitable means.
  • FIG. 8 to 10 there is shown a first embodiment three wheel suspension system particularly suited for use with a solar vehicle of the kind referred to above.
  • the suspension system 50 includes a generally rigid substantially triangular unsprung frame 51.
  • the rear beam 52 of the frame is preferably reinforced to improve castor stiffness.
  • the frame is preferably fabricated in aluminium or other suitable light weight high strength alloy.
  • the embodiment illustrated has twin rear wheels 53 secured to the frame 51 by means of substantially undeformable support members in the form of generally U-shaped brackets 54.
  • the brackets 54 each include a vertical strut 54a which support a wheel axle 55 in the usual manner.
  • a single front wheel 56 is attached via a fork arrangement 57 to a steering post 58 which is rotatably supported in the housing 59 formed on the frame 51.
  • the frame also provided with the frame are four spring towers 60 adapted to house and locate four steel coil springs 61.
  • the two rear springs each have an associated telescopic hydraulic damper 62, one end of each being securable with the frame, the other end being adapted for connection with the vehicle body.
  • a single front damper is mounted to the frame adjacent the rear of, for example, the front wheels aerodynamic spat which forms part of the preferred body structure.
  • the system 50 also includes two rose jointed panhard rods 64 for laterally locating the suspension system relative to the transverse extent of the vehicle, each rod being pivotably connected at a first end 65 with the frame 51 and at its distal end 66 with the vehicle body (not shown) .
  • the panhard rods 64 are generally aligned with the driveshaft 67 such that length compliance in the driveshaft is not needed.
  • alignment of the rear wheels is effected by the relative adjustment of two braces or struts 68 which each extend diagonally from the frame 51 to the rear wheel hub 69.
  • the ends of the braces 68 adjacent the frame are adjustable therewith to alter their respective effective length, thereby altering the alignment of the wheels relative to the frame.
  • the wheel axle supports are mounted to the frame by means of a conventional tapered joint such that the wheel hubs can be locked to the frame in any predetermined alignment.
  • the suspension system 50 can be seen to comprise a generally rigid substantially triangular unsprung fore or aft first subframe 51a coupled to a second similarly rigid subframe 51b.
  • the first rigid subframe 51a has two spaced wheel axles 55 connected therewith at or adjacent opposing vertices of the frame.
  • the second rigid subframe is generally 'T' shaped and has two wheel axes 55 connected to opposing ends of the cross member 70 of the 'T' frame 71.
  • the distal end of the centre stem of the 'T' member 72 is of a generally circular cross-section and is mounted for rotation about a fore to aft longitudinal axis 73 by means of two longitudinally spaced bearings 74 housed in the free apex of the first subframe 51a.
  • both subframes 51a and 51b are substantially triangular and configured such that on assembly they share a common cross member 75.
  • One subframe 51a has two opposed centre wheel axles 55a and a third rear or front transversely centered axle 55b.
  • the other subframe 51b is pivotably connected to the first subframe at two locations adjacent each of the respective centre wheel axles 55a for rotation about a transverse axis 76 and includes a further front or rear transversely centered axle 55c.
  • springs and/or a damping elements can be connected in the manner previously described to support, isolate and/or cushion the vehicle body from the rolling gear.
  • Axle mounts, steering gear, control arms and other body locating systems can also be incorporated into the system in the manner well known to those skilled in the art.
  • FIGs 15 and 16 there is shown an electrical battery power source configuration for driving a single load, such as, for example, an electrical motor.
  • the battery source configuration 1 includes first and second battery sources 2 and 3 respectively connected to first and second inputs 4 and 5.
  • the inputs 4 and 5 are also connected to a controller shown generally at 6 which is in turn connected via an output 7 across the load 8.
  • the controller 6 is operated to selectively electrically connect both battery sources 2 and 3 to the load 8 so as to control the current flow to the load and the individual current flow levels drawn from each source.
  • Selecting a suitable battery source is a fairly difficult decision particularly when influenced by so many factors including weight or charge density, cost, cycle life, power yield variation with temperature or time, cold rechargeability, etc. It is virtually impossible to select one single battery source that meets all the relevant criteria for a given application.
  • silver zinc batteries have been one of the most popular choices as having the highest charge density and therefore lowest overall weight addition to the vehicle.
  • these are not ideal as they have only a short cycle life of about 10 cycles and a high initial cost.
  • they must be treated cautiously as high recharge or discharge rates can destroy the batteries or at least impair their overall efficiency.
  • lead acid batteries can tolerate fairly abusive recharge and discharge rates and are relatively inexpensive.
  • lead acid batteries are also bulky and extremely heavy.
  • the first and second sources in the configuration 1 now comprise a bank of the rechargeable lead acid cells 10 forming the first battery source 2 and a bank of the Lithium cells 11 forming the second battery source 3. These sources 2 and 3 are each connected to respective controllers 12 and 13. The controllers are in turn connected across the load which takes the form of a DC drive motor 14 operatively connected to one of the vehicle wheels.
  • the preferred controllers are produced by AERL and sold under the trade name 'Motormax'.
  • a solar photovoltaic panel 15 is also connected to the controller 12, desirably via a panel output energy optimising device 16 such as the unit produced by AERL and sold under the trade name 'Maximiser'.
  • the controller is set to limit the maximum current drawn and, in accordance with one preferred strategy, deliver a constant current to the motor 14.
  • the preferred current draw level will ideally be around lOOmA but may be as high as around 600mA or even 2 amps and will be determined by the race strategy used.
  • the driver is the central processing unit and operates the regulating means associated with the two or three separate load controllers.
  • a computer control system is utilized which determines the relative output to be drawn from each source according to the load required by the motor for the given ground and weather conditions and the reserve capacities of each battery source etc.
  • the lead acid batteries comprise two separate banks of cells, each string having approximately the same open circuit output voltage when at the same percentage level of charge, one bank being made up of lead acid 'X' cells each having a nominal capacity of 5.4Ah at a 20 hour discharge rate and the other of lead acid 'J' cells having a designated nominal capacity of 13Ah at the same discharge rate.
  • lead acid 'X' cells each having a nominal capacity of 5.4Ah at a 20 hour discharge rate
  • lead acid 'J' cells having a designated nominal capacity of 13Ah at the same discharge rate.
  • the voltage at which current is drawn from the lead acid battery sources will vary according to the state of charge of the cells and the current draw level, the higher the current draw, the lower the voltage.
  • the output voltage of Lithium batteries is fairly constant until almost fully discharged, the output voltage varying only with current draw.
  • the varying voltages in the power system are managed by the controllers such that the voltage delivered to the motor from each source is substantially the same.
  • the electrical battery power source configuration and method of operation according to the invention enables a designer to tailor the battery source to achieve a combination of characteristics not currently available with any one single battery type.
  • maximum energy is obtained from the Lithium battery source by preferably using a substantially constant low current level discharge even as the motor load varies.
  • the "bullet proof" recharge and discharge characteristics of the lead acid batteries can also be fully exploited to make use of extra available power.
  • a lead acid/silver zinc combination has the advantages in that the lead acid can be used to 'buffer' the recharging of the silver zinc. In this way high energy peaks can be used to recharge the 'robust' lead acid batteries which can then be used subsequently to trickle charge the more 'delicate' silver zinc batteries.
  • Nickel Cadmium batteries can also be used as part of a combination such that they can be fully discharged before recharging to prolong their cycle life and maintain their design capacity.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Photovoltaic Devices (AREA)

Abstract

Un système de suspension (50) pour un véhicule léger comprend un châssis (51) non suspendu sur ressorts, conçu pour soutenir au moins trois roues devant tourner autour d'axes parallèles (55), cela au moyen d'éléments de support (54) pratiquement indéformables, reliés au châssis (51), celui-ci étant pratiquement rigide entre au moins deux des axes (55). Ledit système comprend également des éléments élastiques amortisseurs (61, 62) conçus pour coopérer avec le châssis (51) pour soutenir et isoler la carrosserie d'un véhicule. Le système de suspension présenté (50) peut comprendre 4 roues, et son châssis (51) peut avoir deux parties pivotantes. Sont également décrits et revendiqués, en tant qu'équipements pour véhicule à énergie solaire, une batterie de piles solaires montée sur une surface courbe, une structure stratifiée de panneaux solaires, et une source d'alimentation électrique constituée de batteries.
PCT/AU1994/000510 1993-08-31 1994-08-31 Systeme de suspension pour vehicule a energie solaire WO1995006569A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU76059/94A AU7605994A (en) 1993-08-31 1994-08-31 Suspension system for solar powered vehicle

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
AUPM0946 1993-08-31
AUPM094693 1993-08-31
AUPM1831 1993-10-14
AUPM183193 1993-10-14

Publications (1)

Publication Number Publication Date
WO1995006569A1 true WO1995006569A1 (fr) 1995-03-09

Family

ID=25644532

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/AU1994/000510 WO1995006569A1 (fr) 1993-08-31 1994-08-31 Systeme de suspension pour vehicule a energie solaire

Country Status (1)

Country Link
WO (1) WO1995006569A1 (fr)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU5366459A (en) * 1959-10-14 1960-04-14 Motor-driven crosscountry vehicle
AU1379066A (en) * 1966-11-23 1968-05-16 Garrett Enumclaw Co Chain driven articulating frame vehicle
AU2283367A (en) * 1967-06-07 1968-12-12 Owens Illinois, Inc Positive traction system for vehicles
EP0048659A1 (fr) * 1980-09-19 1982-03-31 SOCIETE D'EXPLOITATION DES RESSORTS AUTO-AMORTISSEURS JARRET Société Anonyme dite: Véhicule terrestre à coque suspendue

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU5366459A (en) * 1959-10-14 1960-04-14 Motor-driven crosscountry vehicle
AU5768065A (en) * 1965-04-15 1966-10-20 Vehicle, particularly car, of small size suitable for use in town
AU1379066A (en) * 1966-11-23 1968-05-16 Garrett Enumclaw Co Chain driven articulating frame vehicle
AU2283367A (en) * 1967-06-07 1968-12-12 Owens Illinois, Inc Positive traction system for vehicles
AU6524769A (en) * 1968-12-10 1971-06-17 Wilfred Sessions Donald Snowmobile undercarriage conversion unit
EP0048659A1 (fr) * 1980-09-19 1982-03-31 SOCIETE D'EXPLOITATION DES RESSORTS AUTO-AMORTISSEURS JARRET Société Anonyme dite: Véhicule terrestre à coque suspendue

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