WO2000046065A1

WO2000046065A1 - A transport system

Info

Publication number: WO2000046065A1
Application number: PCT/IB2000/000085
Authority: WO
Inventors: John Henry Talbot
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-02-02
Filing date: 2000-01-28
Publication date: 2000-08-10
Anticipated expiration: 2001-08-02
Also published as: AU2123100A

Abstract

A transport system according to the present invention includes a road having a plurality of conductors laid on or in the surface of the road. The plurality of conductors are inserted onto or into the road surface during the final rolling phase of a new road or a road that is resurfaced. The conductors are in electrical contact with an AC or a DC power supply. A vehicle with an electric motor has contact members connected to the underside of the vehicle. When the contact members are in contact with the plurality of conductors, power is transmitted from the power supply to the electric motor of the vehicle. Due to the configuration of the conductors and the contact members, lateral movement of the car on the road is not restricted.

Description

A TRANSPORT SYSTEM

BACKGROUND OF THE INVENTION

THIS invention relates to a transport system for connecting electrically propelled vehicles to an external power source without the mobility limitations of the prior art.

Known prior art typically comprises the use of electrified rails or overhead catenary conductors or a combination of these. Whichever of these is used, the mobility of the vehicles is limited. For example, trams have to keep to the rails and trolley buses have to keep within a certain distance of the catenary. Manoeuvres such as overtaking and turning around on the road are not possible.

These limitations are addressed by the present invention. SUMMARY OF THE INVENTION

According to the present invention there is provided a transport system comprising:

a vehicle having an electric motor and a contact member located at least partially exterior to the vehicle, the contact member being in electrical contact with the electric motor;

a plurality of conductors located on or in the surface of a road for the vehicle, the plurality of conductors having an area thereof exposed for contact with the contact member of the vehicle, the plurality of conductors being arranged on or in the surface of the road so that the vehicle is able to move transversely across at least a portion of the width of the road while the contact member is in contact with the plurality of conductors; and

at least one power supply connected to at least one of the plurality of conductors so that when the contact member of the vehicle is in contact with the plurality of conductors, power is supplied to the vehicle.

The plurality of conductors are preferably arranged on or in the surface of the road so that the vehicle is able to move transversely across the majority of the width of the road while the contact member is in contact with the plurality of conductors

In one embodiment, the plurality of conductors may be plates which are spaced apart from one another.

Alternatively, the plurality of conductors may be portions of wire mesh which are laid in the road surface with at least some of the wires being submerged in the road surface and at least some of the wires being exposed for contact with the contact members of the vehicle.

Alternatively, the plurality of conductors are placed in the road surface at an angle to the longitudinal direction of the road.

The at least one power supply may be a DC power supply, in which case alternate conductors of the plurality of conductors are connected to alternate poles of the DC power supply.

The at least one power supply may be an AC power supply.

Preferably, the transport system further comprises switch means connected to at least one of the plurality of conductors, the switch means being adapted to connect the at least one conductor to the at least one power supply when the contact member of the vehicle is in contact with the at least one conductor, and wherein the switch means disconnects the at least one conductor from the at least one power supply when the contact member of the vehicle is not in contact with the at least one conductor.

The switch means may be a thyristor or a bidirectional triode thyristor.

According to the present invention there is further provided a transport system comprising:

a plurality of conductors located on or in the surface of a road for vehicles, the plurality of conductors having an area thereof exposed for contact with a contact member of a vehicle, the plurality of conductors being arranged on or in the surface of the road so that the vehicle is able to move transversely across at least a portion of the width of the road while the contact member is in contact with the plurality of conductors; and

The at least one power supply may be an AC power supply.

The switch means may be a thyristor or a bidirectional triode thyristor.

According to the present invention there is further provided a vehicle comprising:

an electric motor; and

a contact member connected to the electric motor, the contact member being spaced apart from and below the vehicle so as to be in contact with at least one power supply via at least one conductor placed on or in the road on which the vehicle travels.

The vehicle preferably includes a rechargeable battery connected to the contact member and to the electric motor.

The contact member may be a roller which is connected to an arm which is in turn connected to the vehicle by pivot means to allow the roller to move closer and further away from the vehicle, depending on the road surface.

Alternatively, the contact member may be brush which is retractable into and out of the vehicle.

The vehicle may include transmitting means to transmit a signal via the contact member to switch means in the road so that the switch means connects the at least one conductor to the at least one power supply when the contact member of the vehicle is in contact with the at least one conductor, and wherein the switch means disconnects the at least one conductor from the at least one power supply when the contact member of the vehicle is not in contact with the at least one conductor.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a view of the road surface with a plurality of conductors located therein according to the present invention;

Figure 2 is a vehicle including contact members according to the present invention;

Figure 3 is an enlarged view of one of the contact members of Figure 1 ;

Figure 4 is a schematic view of the motor of the vehicle according to a first embodiment of the present invention;

Figure 5 is a schematic view of the motor of the vehicle according to a second embodiment of the present invention;

Figure 6 is a view of alternative placement of conductors in a road according to the present invention;

Figure 7 is a view of alternative placement of conductors in a road according to the present invention;

Figure 8 is a voltage versus time diagram; Figure 9 is a schematic illustration of the interaction between the conducting members of a vehicle and the conductors in the road;

Figure 10 is a view of alternative placement of conductors in a road according to the present invention;

Figure 11 illustrates the use of switching means to disconnect the conductors from the power supply when they are not in contact with a vehicle; and

Figure 12 is a schematic illustration of a vehicle including a transmitter thereon in contact with switching means.

DESCRIPTION OF EMBODIMENTS

Referring to Figures 1 and 2, a road surface 10 has a plurality of conductors 12 laid on the surface of the road. In this embodiment of the invention, the conductors are in the form of conducting plates which are laid in the center of the road 10 on which a vehicle is to travel. Where the road is comprised of a number of lanes demarcated by lines 14, the conducting plates are typically placed in the center of each lane.

The plurality of conductors 12 are inserted onto or into the road surface during the final rolling phase of a new road or a road that is resurfaced.

The vehicle 16 has contact members 18 connected to the underside of the vehicle. It will be appreciated that although the vehicle is illustrated with two contact members 18, one contact member or a larger number of contact members could equally be used. The vehicle 16 is a vehicle with an electric motor replacing the conventional internal combustion engine.

Figure 3 shows an enlarged view of one of the contact members 18. In this embodiment, the contact member 18 has a trailing arm 20 which connects a roller 22 to the underside of the vehicle 16. The trailing arm 20 is connected at pivot points 24 and 26 to the roller 22 and vehicle 16 respectively. Both the roller 22 and the trailing arm 20 are electrically conductive to allow current to pass from the conductors 12 to the motor of the vehicle which is in electrical connection with the trailing arm 20. The roller 22 and trailing arm 20 are pivotable about point 24 to allow the roller to pass easily over bumps in the road.

It will be appreciated that although the contact member 18 is illustrated as a roller in this embodiment, a brush or another form of electrical contact member could equally be used. In this case, the brush could be made retractable to give a satisfactory ground clearance. Alternatively, one or more of the wheels of the vehicle could be adapted to act as the electrical contact member.

The plurality of conductors 12, in one embodiment, are connected alternately to the positive and negative terminals of a DC power supply (not shown). In this embodiment, the contact members 18 are spaced apart on the vehicle 16 corresponding to the spacing apart of the conductors 12 in the road. Thus the vehicle 16 is connected to both terminals of a DC power source and remains connected as the vehicle travels along the road, there being a momentary disconnection as the contact members 18 cross the gaps between the conductors 12. In this manner, power is supplied to the motor of the vehicle 16.

Referring to Figure 4, the contact members 18 are connected to inputs 28 on the vehicle 16. The inputs 28 are connected to a bridge rectifier 30 which ensures a constant polarity at its output irrespective of which polarity conductor 12 the contact members are in connection with.

The output of the rectifier 30 is connected to a storage battery 32 and an electric motor 34. The battery is used to power the vehicle 16 over the gaps between the conductors 12 and for short excursions away from the road with the conductors 12 located therein. The battery may also be used at intersections or when changing lanes. This obviates the need for complicated arrangement of conductors at intersections.

The battery is typically a 36 volt battery which could be in the form of three 12 volt car batteries connected together. A typical battery of this nature has a 36Ah rating. Thus in a case where the vehicle crosses an intersection at a speed of approximately 40 km/h, it is estimated that 3kW of power are required. Estimating a current drain of 100A for approximately two seconds, the discharge of the battery would be 0.06Ah.

In this embodiment of the invention, the external DC power supply is a 40 volt supply. Such a low voltage enhances the safety of the system by reducing the chances of electrocution. It will be appreciated that a plurality of such power supplies may be needed to power a long stretch of road. With such a low voltage, a heavy power cable would be needed to supply a large number of conductors 12. Thus the cost of the system is optimised by optimising the number of transformers and the cross section of the cable used to supply the power.

In another embodiment of the invention, the DC power supply is replaced with an AC power supply. Figure 5 shows the configuration of the vehicle for a three phase AC power supply. The conducting plates 12 on the road are each connected to a terminal of the three phase power supply (not shown) and the vehicle has three contact members 18 spaced apart the same distance as the spacing between consecutive plates so that each one of the contact members 18 connects to one phase of the power supply.

The trailing arms 20 are connected to input points 28 which are in turn connected to a three phase motor 34 and a battery 32. A rectifier/inverter 36 is connected between the inputs 28 and the battery 32 and a variable frequency inverter 38 is connected between the inputs and the motor 34.

Alternatively, the motor 34 may be a ducted fan as described in the applicant's book "The Ultimate Motor Car" (ISBN0-620-23908-5, Johannesburg Research Library, 1999), the contents of which are incorporated herein by reference. This has the advantage that the fan can be driven by a nearly constant speed three phase motor connected to the three phase power supply.

The arrangement of the plurality of conductors in the road according to the present invention can take one of a number of alternative forms. In one embodiment, the plurality of conductors are meshes or matrices of conducting material, for example, 50-100 precision mesh. This is a fencing mesh of galvanized iron wires with rectangular apertures of 50mm by 100mm. When these wires are laid on the road there will be wires running parallel to the road direction and wires running transverse to the road direction. The wires running parallel to the road direction are half submerged so that an area thereof is exposed for contact with the contact member 18 of the vehicle 16. The wires running transverse to the road are buried in the road surface.

This wire mesh may be inserted into the road during a resurfacing or resealing operation. Typically, the wire mesh will be broken into convenient pieces of 2 meters long by 1 meter wide. The pieces of wire mesh are connected to the power source by attaching a cable to each piece of wire mesh. Where higher currents are required, typically in excess of 200A, the cables are twisted along the full length of the edge wire to effect efficient current flow. Typically, a gap of 120mm is left between portions of the precision wire in the longitudinal direction. The gap between portions of the wire mesh in the transverse direction should be larger than the widest contact member 18 used. For example, the gap is 100mm wider than the widest contact member 18 to be used on the road. Thus, if the maximum contact member 18 width is 400mm, a gap of 500mm in the transverse direction is preferred.

In the prototype, the wire diameter was 2mm, with a maximum safe current per wire considered to be 20A, bearing in mind the low duty cycle. Since the contact receives current from two directions, the maximum safe current may be taken as 40A per wire. A vehicle contact 200mm wide makes contact with at least four wires at any one time. Thus the maximum safe current that can be supplied with such a system is 160 amps. This can be increased by making the vehicle contacts wider. A 300mm wide contact would provide for a safe current of 240 amps. The prototype road used 220 volts r.m.s. A.C. Thus the maximum power provided by one contact 300mm wide is 52.8kVA. This could be increased by raising the voltage or by using a larger wire diameter. Long vehicles that span the length of several mesh pieces could use many contacts, each making contact with a different plate. In this way very large currents can be supplied.

In a further embodiment, a battery as described above is used which is charged at short intervals by making contact with the plurality of conductors 12 in the road. The conductors are spaced apart so that the battery is charged when in contact with the power supply and the battery is used to drive the motor in the sections between sets of conductors.

The spacing of conductors should vary with the gradient. For down gradient exceeding 1 :20, no conductors are needed as the vehicle can coast. For steep up gradients, conductors should be spaced as close as possible to be continuous. For level roads, a typical spacing would be 10m to 20m apart. Gaps may also be left according to local needs. In places where access to a utility such sewers and drains is required, gaps may be left in the conductors.

Referring to Figure 6, the conductors are positioned in the road as illustrated in the Figure, and the contact members 18 are made wide enough so that the lateral position of the car on the road is not critical. In this case, the use of a bridge rectifier is used to enable the vehicle to travel on the opposite side of the road when overtaking.

On uphill stretches, the conductors are continuous to provide adequate power for hill climbing.

Referring to Figure 7, the line marking the verge of the road is shown as line 40 while the line marking the middle of the road is illustrated as line 42. The conductors are attached to the road in the form of diagonal strips of alternating polarity. The contact members 18 are now spaced apart to make contact alternately with positive and negative conductors in the road surface. The resulting voltage verse time diagram is seen in Figure 8. This system therefore acts as a single phase inverter.

Three contact members 18 may be used in which case the system will serve as a three phase inverter.

Figure 10 shows another embodiment of the invention where the plurality of conductors are placed in the road at intersections or in confined spaces such as parking grounds. Each conductor is connected to the power supply. Where a DC power supply is used, alternate conductors are connected to the positive and negative terminals of the power supply. There should therefore always be at least one contact member 18 of the vehicle in contact with a positive and a negative plate, almost irrespective of the position and orientation of the vehicle. For this to apply, the vehicle 16 needs four contact members 18 positioned as shown in the drawing.

Figure 11 shows a method of connecting the power supply to the conductors which allows a high voltage to be used. The conductor 44 is connected to the positive side 46 of the power supply, while conductor 48 is connected to the negative side 50 which is earthed. Resistor 52 short circuits the forward leakage current switch means in the form of a thyristor 56, which prevents conductor 44 being charged to a high voltage while the thyristor is open. The thyristor 56 is normally open so that there is only a small voltage at conductor 44, being the voltage iR across the resistor 52, where i is the forward leakage current and R is the resistance. When a moving vehicle covers the conductor 44, a transmitter (not shown) on the vehicle sends a signal to a detector in the road which initiates a gate pulse closing the thyristor 56. While a contact member 18 attached to the vehicle is in contact with the conductor 44, the thyristor 56 remains conducting. As soon as contact is broken, the current falls below the holding current of the thyristor 56 and the thyristor ceases to conduct. This enables the safe use of high voltages. It will be appreciated that the circuit of Figure 11 may also be used with the alternate embodiments described above. Where the thryistor 56 is of the bidirectional triode type (triac), the circuit may be used with alternating current.

It will be appreciated that other forms of switching means could be equally as effectively used.

In one form of the invention shown schematically in Figure 12, a multivibrator 58 carried on the vehicle 16 continuously generates a signal of fixed frequency and waveform. The signal is transmitted via the leads connecting the motor 34 to the contact members 18 to a decoder 60 on the ground. Provided that the signal is of the correct frequency and waveform, the decoder transmits it to the gate of the triac 62, which then becomes conducting so that the motor 34 is connected to the power source. As soon as the contact members 18 cease to make contact with the conductors in the road, the triac 62 ceases to conduct electricity and the conductors in the road are disconnected from the power source.

Claims

1. A transport system comprising:

2. A transport system according to claim 1 wherein the plurality of conductors are arranged on or in the surface of the road so that the vehicle is able to move transversely across the majority of the width of the road while the contact member is in contact with the plurality of conductors

3. A transport system according to claim 1 or claim 2 wherein the plurality of conductors are plates which are spaced apart from one another.

4. A transport system according to claim 1 or claim 2 wherein the plurality of conductors are portions of wire mesh.

5. A transport system according to claim 4 wherein the wire mesh is laid in the road surface with at least some of the wires being submerged in the road surface and at least some of the wires being exposed for contact with the contact members of the vehicle.

6. A transport system according to claim 1 or claim 2 wherein the plurality of conductors are placed in the road surface at an angle to the longitudinal direction of the road.

7. A transport system according to any preceding claim wherein the at least one power supply is a DC power supply.

8. A transport system according to claim 7 wherein alternate conductors of the plurality of conductors are connected to alternate poles of the DC power supply.

9. A transport system according to any one of claims 1 to 6 wherein the at least one power supply is an AC power supply.

10. A transport system according to any preceding claim further comprising switch means connected to at least one of the plurality of conductors, the switch means being adapted to connect the at least one conductor to the at least one power supply when the contact member of the vehicle is in contact with the at least one conductor, and wherein the switch means disconnects the at least one conductor from the at least one power supply when the contact member of the vehicle is not in contact with the at least one conductor.

11. A transport system according to claim 10 wherein the switch means is a thyristor.

12. A transport system according to claim 10 wherein the switch means is a bidirectional triode thyristor.

13. A transport system comprising:

14. A transport system according to claim 13 wherein the plurality of conductors are arranged on or in the surface of the road so that the vehicle is able to move transversely across the majority of the width of the road while the contact member is in contact with the plurality of conductors

15. A transport system according to claim 13 or 14 wherein the plurality of conductors are plates which are spaced apart from one another.

16. A transport system according to claim 13 or 14 wherein the plurality of conductors are portions of wire mesh.

17. A transport system according to claim 16 wherein the wire mesh is laid in the road surface with at least some of the wires being submerged in the road surface and at least some of the wires being exposed for contact with the contact members of the vehicle.

18. A transport system according to claim 13 or 14 wherein the plurality of conductors are placed in the road surface at an angle to longitudinal direction of the road.

19. A transport system according to any of claims 13 to 18 wherein the at least one power supply is a DC power supply.

20. A transport system according to claim 19 wherein alternate conductors of the plurality of conductors are connected to alternate poles of the DC power supply.

21. A transport system according to any one of claims 13 to 18 wherein the at least one power supply is an AC power supply.

22. A transport system according to any of claims 13 to 21 further comprising switch means connected to at least one of the plurality of conductors, the switch means being adapted to connect the at least one conductor to the at least one power supply when the contact member of the vehicle is in contact with the at least one conductor, and wherein the switch means disconnects the at least one conductor from the at least one power supply when the contact member of the vehicle is not in contact with the at least one conductor.

23. A transport system according to claim 22 wherein the switch means is a thyristor.

24. A transport system according to claim 22 wherein the switch means is a bidirectional triode thyristor.

25. A vehicle comprising:

an electric motor; and

26. A vehicle according to claim 25 further including a rechargeable battery connected to the contact member and to the electric motor.

27. A vehicle according to claim 25 or claim 26 wherein the contact member is a roller.

28. A vehicle according to claim 27 wherein the roller is connected an arm which is in turn connected to the vehicle by pivot means to allow the roller to move closer and further away from the vehicle, depending on the road surface.

29. A vehicle according to claim 25 or claim 26 wherein the contact member is a brush.

30. A vehicle according to claim 29 wherein the brush is retractable into and out of the vehicle.

31. A vehicle according to any one of claims 25 to 30 wherein the vehicle includes transmitting means to transmit a signal via the contact member to switch means in the road so that the switch means connects the at least one conductor to the at least one power supply when the contact member of the vehicle is in contact with the at least one conductor, and wherein the switch means disconnects the at least one conductor from the at least one power supply when the contact member of the vehicle is not in contact with the at least one conductor.