AU712902B2

AU712902B2 - Power Track - A Practical System for the Universal use of Electrically Powered Vehicles

Info

Publication number: AU712902B2
Application number: AU61990/96A
Authority: AU
Inventors: John Cameron Robertson
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-08-09
Filing date: 1996-08-09
Publication date: 1999-11-18
Anticipated expiration: 2016-08-09
Also published as: AU6199096A

Description

______AUSTRALIA" Re0u ion. I Patents: Act 1.999 Original Complete Specfication Standard PAte nt Invention Ttle~ -C -LnA-~z r o~~ The followin~g statemet is a fuldescrption of tis invention, including the best method of perfrmin~g knownto me. I. b..

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*h *Note: if there is insufficient space above to type the statement of claim, do not use this sheet, but use separate sheets of paper beginning with the words "The claims defining the invention are as follows:" and ending with the date and name of applicant in block letters.

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A Practical System for the Universal Use of IP Australia

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'--ents received on: Electrically Powered Road Vehicles

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3 sEP 1999 1 The "Power Track" Embodying Lane and Separation Control of Vehicles Environmental and Other Benefits The environmental advantages of electrically powered vehicles as opposed to those powered by internal combustion engines are well known and have frequently been described. The principal problem inhibiting their practical use has been the weight and cost of any known system of mobile electrical storage...

4o Problems of Low Performance, Short Range. High Weight and Cost The result of those inhibitions has been that electrical vehicles have severely limited acceleration and/or cruising speed and/or cruising range by comparison with vehicles using internal combustion engines. Their weight and cost has been higher than corresponding IC-powered vehicles.

This Invention Gains the Benefits and Solves the Problems This invention describes a system which uses existing technologies (or extensions thereof) in a new manner to attain a practical system of electrical propulsion for road vehicles. These electrically-powered road vehicles have a performance fully comparable with those which are powered by internal-combustion.

Performance from Electric Vehicles Fully Comparable to IC Vehicles )r the purposes of this invention comparable performance is taken to be: Maximum Acceleration: Not more than 12 seconds to 100 Kilometres per Hour for Cars and commensurate figures for heavier vehicles.

Cruising Speed: Up to 180,KPH (112 mph) on apower track and up to KPH (44 mph) on internal batteries.

Cruising Range: Unlimited within the power track system. Not less than 10 kilometres on internal batteries.

Need to Use a Conductive Energy Pick-Up NOT an Inductive Pick-Up Various patents have been taken out for systems which are based on an inductive power pick-up arrangement for vehicles. Such systems have the great attraction that they do not require physical contact between the vehicle and the source of the electrical energy within the road. They have the fatal disadvantage that they are capable only of transferring small amounts of energy and of doing so with very low efficiencies. The amounts of energy an inductive arrangement can transfer are barely adequate to confer modest performance upon a small car. They are totally inadequate to give good performance to a family car or any performance at all to a heavy goods vehicle.

3oo,;, The purpose of this invention is to create a system which makes on-road, conductive pick-up safe and practicible for all types and sizes of vehicle in all conditions and permits undimished use of the road by existing conventional vehicles.

Materials, Dimensions Times Herein are Representative and not Definitive In this description specific materials, dimensions, voltages, currents, frequencies, wavelengths, times, etc. are set out. These specific figures are representative and not definitive. They may, indeed surely will, be varied in the event to suit the particular circumstances of any given installation.

Achievement of a full working system will entail a large amount of Sdetailed design and development of the necessary component parts.

The Essential Elements of This Invention The elements of this invention essential to attaining its objective are: An electricity supply on the road surface available to all vehicles having a suitable, under-vehicle pick-up device and the appropriately coded switching command device. The electricity supply track sections, power tracks, are divided into electrically independent lengths, circa metres. They form a series of"electrical islands". The length of the sections may be reduced in areas where traffic speeds are usually low.

Control of the electricity supply to each 20 metre section by coded signals from the on-coming vehicle so that the power track section is on only when a vehicle is effectively on top of it. At all other times the electric power is off.

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The system by which electrical leakage from a live conductor to earth in wet or damp conditions is minimised is a key feature of this invention. The conductors are set in an insulating base which has a very smooth, water repellent surface coating.

Electricity pick-up and return arms, the power arm system are fitted to the underside of each vehicle. They provide the electrical supply and earth return for that vehicle as long as it is on apower track. 0 Safety of the on-road supply system is ensured by the power to each power track section being turned on only after the receipt of a properly coded signal by its section sensor from the vehicle transmitter on a vehicle about to enter that section (the transmitter code). The power goes off automatically 1.5 seconds after receipt of the signal. It is controlled by the section controlprocessor and the section switch. The on-road-supply system fails safe with the power off. Power-off is the normal condition of a power track.

A small bank of conventional lead-acid batteries provides power for the vehicle when it is off the power track system or crossing intersections and the like. The power form the power track can charge the batteries in addition to driving the vehicle.

Electric motors driving each pair of wheels on one or more axles of the vehicle. These motors provide a maximum of 60 kW per tonne for cars 3SP- alling to some 10 kW per tonne for heavy, laden trucks.

An electronic control system to ensure seamless changeover frompower track to battery and vice versa.

A position Detector which detects the centre line of the power track and the vehicle's lateral position in relation to it. This is used by the power arm to actively centre its electrical brushes on the power track by adjusting its position across the width of the vehicle.

Options The position Detector may also be used to provide automatic lane control for the vehicle. (See further below). Optionally the vehicle may have a "head-up display" in the windscreen showing the exact position of the vehicle in relation to the power track it is following. Most drivers will find it fairly easy, merely by looking at the road ahead, to get in the correct position and to stay there.

The system may, optionally, be used to provide passive or active automatic vehicle control on both the x and y axes.

Further System Details The power tracks end a short distance before road junctions, pedestrian crossings and the like. These are negotiated by the vehicle using its internal power supply. Similarly power tracks may be excluded from housing areas, shopping centres or in densely-peopled inner city areas. In such areas a vehicle uses its internal battery power. Each section ofpower track has an overload cut-out which turns off the power to that section for a specified period if an excessive current is experienced. A trial restoration is attempted after 5 minutes and, if that is unsuccessful, one further trial restoration 5 minutes later. If this last fails a message goes to central control that attention is required on site.

The entire system is monitored from central consoles which show the status of each individual power track section as well as the overall system parameters.

An automated mobile cleaning system brushes and vacuums the tracks and conductors and the adjoining road surfaces at intervals. The length of those intervals depends on the local conditions but will normally be at least once per day.

The heating consequent on the electrical current flow means that in frost prone areas snow and ice adjacent to the tracks tend to melt automatically. If the power tracks become snow or ice bound they cease to be useable. Under no circumstances must salt be used to melt ice on roads with a power-track installation.

Roads with the power track system installed are entirely compatible with all established uses of the road by pedestrians, by cyclists, by animals and by conventional vehicles of all sorts.

The power track system may be installed in any new or existing well-maintained and well-drained road. The capital cost is circa US$100,000 per kilometre of road with one lane in either direction.

This does not include the capital cost of providing the necessary electricity generating and distribution capacity. The power arm pick-up system is automatically retracted when reverse gear is selected. Each vehicle has electric motor(s) to power at least two wheels and possibly all its wheels. These motors are permanent magnet, brushless DC machines and run at the main supply voltage. That means that the main AC supply is rectified before being delivered to the motors. The: power from the batteries is "chopped" and transformed before being rectified and delivered to the motors.

So The transformer may be used to step up the voltage from the batteries to the motors or to step down the voltage from the main supply so as to top up the batteries. Its rated output is approximately 20% of the full motor power.

Each vehicle has a coded, microwave command device which enables it to turn on power as it approaches each track section. Possession of a valid code requires up to date payment of the vehicle electricity account and an up to date vehicle licence. (Note that in the absence of a code, limited local use of the vehicle is still possible using internal power and domestic re-charging).

m It is important to eliminate electrical sparking as each vehicle's power arm leaves the end of each power track section. This is done by industry-standard devices in both the power track circuit and on board the vehicle.

Each vehicle carries a number of deep cycle, sealed absorbed technology, 12-volt lead acid batteries 5 for a family saloon car) to give power for short distances outwith the in-road power track system. These provide internal power for access to housing and like areas and are also used to traverse road intersections or to change lanes or roads. They allow even heavy vehicles to accelerate rapidly from traffic lights and other stoppages.

These batteries are re-charged either from a normal domestic supply or while running on the in-road supply system. City car parks and other parking lots will commonly come to offer re-charge whilst vehicles are parked.

1* Each vehicle has an array of solid state devices to ensure smooth transition from external to internal power, to transform voltages, to convert AC to DC or conversely, to allow battery re-charge from the in-road system, to limit the amount of current drawn, to prevent motor or battery overheating and to provide re-generative braking.

Each vehicle has a digital electricity meter to record both its total consumption and its maximum demand. It also records the corresponding location and time of day. This enables the meter to give a sophisticated demand profile which, in turn, allows sophisticated charging properly related to true costs. Each vehicle will display to the driver its instantaneous electricity cost per hour and per kilometre and also its cumulative electricity cost in total and per Km since the last meter payment.

Each vehicle may have an optional "head-up display" of various important parameters to optimise the efficiency and ease of use of the vehicle.

The resultant vehicle performance, weight and cost is competitive with equivalent vehicles using internal combustion engines.

The system may readily be extended to provide, while on the power track ~system, for automatic driving, navigation and other enhancements.

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The vehicle transmitter code may be used to give unimpeded access to and record the charge for the use of toll-ways or toll-bridges. Thus this method is based upon using an "on-ground" delivery system for the electrical power; the power track This decision in turn gives rise to problems of operation in floods or in snow and ice and to safety concerns., These problems are addressed in this method.

Design Aims of the Power Track The aims of the design of the Power Track are that it will: Be safe for all road users Be an efficient provider of electrical power to all user vehicles Enable all user vehicles to attain a performance at least comparable with conventional IC-engined vehicles Afford unlimited cruising range on the power track system Minimise electrical losses in bad weather and like conditions Realise fully the environmental benefits of an all-electric system o Be cost effective in all respects Offer optional enhancements to safety via automatic lane and separation control for user vehicles and the elimination of flammable fuel. oo.o Detailed Description of a Power Track Section The live conductor is made of copper and is 200 mm wide and 1 mm deep. At the time of installation it is bonded to the supporting concrete tiles by an epoxy resin adhesive. The neutral/earth conductor is also the cover of the drainage channel and consists of a strong galvanised steel grid. It runs on that side of the live conductor which is nearest the centre line of the road. It is insulated from the live line by the body of the concrete tiles. It is an open grid surface which allows water to drain freely through it in addition to being an electrical conductor. The neutral/earth, metal conductor is extended in the form of a galvanised steel strap across the division between successive power track sections and down the "undrained" (inner) side of the power track section. This ensures that live voltage cannot leak beyond the confines of that power track section.

The live conductor is set upon a series of insulating concrete tiles. Each of these is, 1,000 mm long, 600 mm wide and 60 mm deep. The live conductor is 30 mm above the road surface with both concrete sides sloping down across 200 mm to the road. Each power track section is metres long and thus has 20 tiles. Each power track section has its own section conductor which is 19,600 mm long, 1 mm deep and 200 mm wide. It consists of copper strip. At the time of installation it is bonded to the tiles by an epoxy resin. Each kilometre of power track requires some 1.7 tonnes of copper per lane.

There are two 200 mm gaps between each section conductor to ensure that they are electrically independent of one another. The neutral/earth galvanised steel strap (bonded to the neutral/earth conductor/drain cover) is run at right angles across the gap and on the road surface down to the opposite side of the power track section to ensure that live voltage cannot leak across in wet or damp conditions. The strap is 20 mm wide. It crosses at road surface level between adjacent power track sections. The last tile in each 20-metre power track section is swept down 3 0 mm to road surface level over a horizontal distance of 200 mm at its end as well as at its side. Similarly the first tile in each section is swept up 30 mm from road surface level. This gives an electrical gap of 400 mm in total between each power track section. There is a 190 mm gap between the start or end of eachpower track section and the earth/neutral strap. The purpose of this arrangement is to minimise electrical leakage in wet or damp conditions by ensuring good run-off of rainwater, etc. from the end and start of each section.

By reason of the isolating gap between each power track section there is a momentary break in power supply as the vehicle passes from one section to the next. At vehicle speeds of 50 KPH and above the supply is ON for 98% of the time and OFF for 2% of the time. The inherent smoothing characteristics of the vehicle's electrical installation ensure this break is imperceptible.

As described above it is important to eliminate electrical sparking as a 7 ,vehicle's power arm passes off the end of each power track section. If _Aarking is allowed to occur it has two deleterious effects. The first is the production of oxides of nitrogen or ozone. Both gases are atmospheric pollutants at ground level. Oxides of nitrogen will also dissolve in rainwater and render it much more conductive. This will lead to increased electrical leakage in wet conditions. The other bad potential effect is metallic deposition tracking of the insulated separation between adjacent power track sections. It is thus vital that the spark suppression equipment in both power tracks and user vehicles are kept in good condition.

The neutral/earth conductor is also the cover on the drainage channel.

Its top surface is level with the road surface. It is made of a galvanised, mild steel grid placed over standard, concrete drainage channels about 250 mm square. The top surface is slotted to allow free ingress for surface water. (The daily cleaning routine, described elsewhere, ensures the grids do not become clogged with leaves or other debris), The steel conductors/covers come in standard 20 metre lengths. They are electrically bonded to the (aluminium) neutral/earth line which runs below the power track and parallel to the live line. When apower track is being installed there are means on site to bend the steel through one or more small angles (1 to 4 degrees per metre of run) to accommodate the curve(s) in the road. The drainage channel and thus the neutral earth conductor is placed on the "high" side of the road, that is to say it is towards the centre of the road relative to the power track section. That is where surface water, if any, flows to. It drains by gravity from the other side. This assumes that the road surface has a conventional, self-draining profile which is high in the centre and falls gradually to either side. Drainage channels may be provided on both sides of the power track if there is reason to doubt the natural drainage properties of the road profile. The neutral earth conductor is on the "outer" side only.

The concrete tiles are coated with PTFE to improve insulation and, more particularly, to cause them to shed water and/or prevent its forming a continuous film on the surface.

Control of Electrical Leakage in Wet Conditions The sensitivity of the power track section sensor is such if there is more than 5 mm of water on the road (which will also cover the sensor face) <af e! UHF radio signal from the vehicle is completely absorbed by the water and no signal will be received by the sensor. In those conditions the power track section remains OFF, the vehicle has to rely on its batteries to carry it over the flooded part and, of course, there is no electrical leakage from the power track section.

The worst case conditions for electrical leakage occur when there is heavy rain falling, when that rain carries significant traces of acid or salt and when the water-shedding properties of the PTFE coating on the tiles has become ineffective. The resistance of the potential 1 mm deep, continuous water film on either side of the power track section is such that in this "worst case" the electrical power leakage from the conductor to earth will be circa 1 kW per power track section during each second period when the track is live. This will compare with an average useful power consumption by a vehicle on that track of around 40 kW.

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Power Track is Not Used in Seaside Locations This assumes that power tracks are not used in seaside locations where storms may drive sea water as a liquid or heavy spray directly onto the road.

The Power Arm Device to Collect Power for the Vehicle 00 The power arm pick-up device is located on the underside of the vehicle 0' and approximately mid-way between the steering wheels and the driving wheels. It can move from side to side along a slider arm located just below the underside of the vehicle and for the full width of that vehicle. This lateral movement is controlled by a hydraulic cylinder which, in turn, is controlled by input from the positiondetector which detects the location of the power track in relation to the vehicle.

Eachpower arm contactor is a reinforced, replaceable graphite block. It is some 30 mm square for a car and some 60 mm square for a heavy truck. When in the contact position both power arm contactors run in close and continuous contact with the live and neutral/earth conductors respectively.

An alternative design of contactor capable of rolling contact with sufficient contact area and sufficient conductivity may be used subject to 7 further design study.

the production of oxides of nitrogen or ozone. Both gases are atmospheric pollutants at ground level. Oxides of nitrogen will also dissolve in rainwater and render it much more conductive. This will lead to increased electrical leakage in wet conditions. The other bad potential effect is metallic deposition tracking of the insulated separation between adjacentpower track sections. It is thus vital that the spark suppression equipment in both power tracks and user vehicles are kept in good condition.

The neutral/earth conductor is also the cover on the drainage channel.

Its top surface is level with the road surface. It is made of a galvanised, mild steel grid placed over standard, concrete drainage channels about 250 mm square. The top surface is slotted to allow free ingress for surface water. (The daily cleaning routine, described elsewhere, ensures the grids do not become clogged with leaves or other debris), The steel conductors/covers come in standard 20 metre lengths. They are electrically bonded to the (aluminium) neutral/earth line which runs .9 below the power track and parallel to the live line. When apower track is being installed there are means on site to bend the steel through one or more small angles (1 to 4 degrees per metre of run) to accommodate the curve(s) in the road. The drainage channel and thus the neutral earth conductor is placed on the "high" side of the road, that is to say it is towards the centre of the road relative to the power track section. That is where surface water, if any, flows to. It drains by gravity from the other side. This assumes that the road surface has a conventional, self-draining profile which is high in the centre and falls gradually to either side. Drainage channels may be provided on both sides of the power track if there is reason to doubt the natural drainage properties of the road profile. The neutral earth conductor is on the "outer" side only.

Control of Electrical Leakage in Wet Conditions The sensitivity of the power track section sensor is such if there is more than 5 mm of water on the road (which will also cover the sensor face) he UHF radio signal from the vehicle is completely absorbed by the water and no signal will be received by the sensor. In those conditions the power track section remains OFF, the vehicle has to rely on its batteries to carry it over the flooded part and, of course, there is no electrical leakage from the power track section.

0***Se Power Track is Not Used in Seaside Locations This assumes that power tracks are not used in seaside locations where storms may drive sea water as a liquid or heavy spray directly onto the road.

The Power Arm Device to Collect Power for the Vehicle The power arm pick-up device is located on the underside of the vehicle and approximately mid-way between the steering wheels and the driving wheels. It can move from side to side along a slider arm located just below the underside of the vehicle and for the full width of that vehicle. This lateral movement is controlled by a hydraulic cylinder which, in turn, is controlled by input from the positiondetector which detects the location of the power track in relation to the vehicle.

Each power arm contactor is a reinforced, replaceable graphite block. It is some 30 mm square for a car and some 60 mm square for a heavy truck. When in the contact position both power arm contactors run in close and continuous contact with the live and neutral/earth conductors respectively.

An alternative design of contactor capable of rolling contact with sufficient contact area and sufficient conductivity may be used subject to 7Nfurther design study.

If conditions make it advisable the power arm contactor may have a small rotating brush immediately in front of it to ensure that the contact surface is clear of grit, dust, etc.

The power arm has two elements the live on-ground, pick-up and the earth retumn arm. Both of those are on the same spindle on the horizontal slider arm on the underside of the vehicle. Both rotate up and down in unison. The two contact areas are 300 mm apart, edge to edge, in the horizontal plane.

Each time the live power arm contactor goes from one power track section to the next it has to cross a "dip" which is 30 mm deep. The power arm assembly may be fitted with a limiting device which prevents the live arm being less than 10 mm lower than the neutral/earth arm. If fitted this reduces the tendency for the arm to bounce. It does require accurate placement of the in-road conductors and the maintenance of that accuracy.

System Does NOT Interfere with Other Road Users The system, when installed, does not inhibit continued use of the road by conventional IC-powered vehicles. In due time legislation may limit the use ofpower track roads by IC vehicles (for environmental and like reasons) but the installation itself does not impose limitations. o*oo Unlimited Vehicle Range Within the Power Track System In normal operation vehicles will use this supply rather in the manner of an electric train. This will ensure very good performance and, within the power track utility system, unlimited range.

Power Track is OFF unless expressly signalled on Safety of the "in-road" electrical supply track is obtained by dividing the power track supply line into relatively short (circa 20 metre) and electrically-independent sections. The normal condition of those power tracks is power OFF.

The Power Track Sensor and Vehicle Transmitter System Apower track sensor is fitted at the start of each track section. The vehicle transmitter is fitted almost at the front of the vehicle and lies across the full vehicle width. The transmitted "beam" covers a rectangle equal to the width of the vehicle and 400 mm from front to back at road level. The transmission is at the upper end of the UHF radio frequency range. The precise frequency used will depend on agreement on a common figure suitable for use in a variety of national circumstances.

An entire code sequence (like a very fast Morse code) is transmitted once every two milliseconds. The actual code is transmitted over, a period of 1 millisecond. The transmitter is then "silent" for 1 millisecond.

Then the sequence begins again.

At the vehicle's maximum cruising speed of 180 KPH it takes 8 milliseconds for the 0.4 metre beam length to pass over a sensor. Thus there are four opportunities for the code to be received correctly and recognised. At lower vehicle speeds there are proportionately more such opportunities.

•go• It follows from the relative positions of the transmitter and pick-up respectively on the vehicle that the sensor will receive a vehicle's signal at least 2.5 metres travel time before the arrival of the pick-up contactor. If the vehicle is travelling at 180 kph it follows that the 0 switching has to be completed in no more than 50 milliseconds. The sensor/switch design provides for a maximum switching period of milliseconds. This is readily attainable with modem techniques.

Power is ON only for a 1.5 Second Period This arrangement is one of the keys to making thepower track system safe.

Power is switched to a section only when its sensor has received a coded signal from a vehicle just about to enter that section and then only for a period of 1.5 seconds. The power then goes off automatically. It cannot be turned on again unless and until another coded signal is received from a vehicle at the entry point to the section. The section switch is loaded in the OFF position both by a spring and by gravity.

A vehicle travelling at only 48 kph traverses the section in just seconds. Thus the 1.5 second allowance allows such a slow vehicle to have power throughout its traverse of the section. If a vehicle travels more slowly or even comes to a halt (say, due to traffic congestion) it needs to use its battery power (or its momentum if applicable) to reach the next section.

The duration of the "power-on" period may be changed depending on local conditions.

If a single lane is carrying 10,000 vehicles per day a very high traffic density the power will be "on" for 15,000 seconds, i.e. for just over 4 hours or some 17% of the whole day. Losses due to power leakage are limited to that portion of the day when the power is "on" Switching is Done When Current Flow is Zero 1* From the standpoint of the life and reliability of the switch gear it is important to note that this system means that if traffic is flowing relatively freely (over 50 KPH) all switching is carried out when there is no current flow to the track section. If power is switched off when a vehicle is stationary or travelling slowly the current flow which has to be switched is relatively low. Peak Total Power Demand along a Section of Road The total power demand for a length of level road, say 1 kilometre, depends on the number of lanes and the mix of traffic. During busy times the effect of traffic density largely cancels itself out. If vehicles are travelling fast (and therefore using relatively high power) They are separated by relatively long distances. Conversely, when the traffic is only moving slowly and the vehicles are, therefore, rather tightly bunched each vehicle's power requirement is low which helps offset the relatively large number of vehicles drawing that power.

If vehicles are all travelling at 100 kph and are passing at 2 second intervals (measured from nose to nose) there will be 18 vehicles per kilometre of lane. At most, those vehicles will have an average power ddemand of 50 KW each. (If the vehicles are travelling more slowly there will be more vehicles per kilometre but their individual power demands will also be less.) Thus the peak gross power demand per kilometre of lane will (at efficiency) be about 1 MW. This will represent a top figure and average demand across the system will be much lower.

This demand will be exceeded where there is a long, steep climb and many heavy vehicles are clustered in the same lane. Where such a condition exists the local peak demand may be around 5 MW per kilometre of lane and appropriate reinforcement of the incoming power supply lines is needed. The standard power track sections are quite capable of supplying this high demand. The fact that power is supplied to both the uphill and the downhill lanes from the same cable means that there is a substantial degree of offset from the regenerative braking current input on the downhill side to help supply the high power needed on the uphill side. 99.9 A Power Track Lane is One Way Only 9: It is evident from this method of operation that any power track lane is ii one way only (as is desirable anyway) if the vehicle wishes to use the power track supply.

Hierarchy of the Power Supply System Each road has a single main supply cable which normally runs under the centre line of the road. This applies to divided highways as well as to smaller roads. Clearly in those instances where divided highways are far apart separate cables will be needed. The cable has cross connections to the switches on each power track section.

All parts of this "cable" consist of insulated aluminium rod. The main supply cable is typically 40 mm in diameter and the cross connections to each power track section control switch are typically 8 mm in diameter.

The rods are laid in trenches in the road. There are flexible connections to bond the cross cables to the main cable and also to each power track section control switch.

n The neutral/earth cable is very similar to the live cable except that it is protected against corrosion but not otherwise insulated and is connected to the neutral/earth drain covers instead of to the live switch.

The main supply cable is divided into 2 kilometre lengths. Each length is connected to (and may be isolated from) the main power supply system via a transformer giving the required, "on-road" voltage. This is typically 2,000 volts AC. This means that the heaviest truck (which can draw up to 400 KW) will draw some 270 rms amps at 0.75 power factor.

The transformer also has the ability to regulate its output voltage further downwards to keep the total zone demand within acceptable limits.

However, the utility will ensure that facilities are sufficient to meet normal maximum demands and "brown out" will only be used in unusual circumstances.

On Board Lead Acid Batteries for Use Outwith a Power Track System All vehicles also have a lead-acid battery system capable of giving a kilometre range at 70 KPH (44 mph) when outwith the utility system.

This is used to access local housing areas or other places Where apower track is not installed. It is also used where there are short breaks in the utility system, for example at cross-roads, road junctions, roundabouts and when changing from one road or one lane to another. The capacity and rate of discharge of the batteries are such as to allow even heavy vehicles to accelerate satisfactorily from traffic lights. The battery provides the power for the first 50 metres or so of the acceleration phase. The main power track supplies power for the remainder of the acceleration.

Again internal battery power is used on any section of road where it is deemed inadvisable (say, by reason of its being prone to flooding) to run the in-road power track supply lines. The vehicles' internal batteries also provides back-up power enabling vehicles to continue on their way if there is a power supply failure even over some kilometresof roadway.

Whenever a vehicle is on the utility system its battery (if less than fully charged) is automatically "topped-up" from that system. There are also facilities to re-charge overnight from a normal domestic electricity supply or in a suitably equipped car park.

"Traffic Calming" in Populated Areas The fact that power tracks are not provided in housing or shopping areas nor adjacent to schools or like locations has the incidental effect of providing an involuntary degree of"traffic calming" in those areas. This is because performance on a vehicle's batteries is considerably less than on a power track.

Vehicles are Almost Silent Another desirable feature is that vehicles are almost silent. This causes much less disturbance to residents than do i/c engined vehicles.

Paradoxically, the silence of electric vehicles is such that some artificial noise may be needed to give aural warning of approach Maximum Permissible Power Demand on the System "a There is a limit set to the amount of power any one vehicle can draw from the system. Typically the top limit is circa 400 KW for heavy vehicles and circa 80 KW for saloon cars. The vehicle is able to partition the corresponding maximum allowable current between its motor(s) and re-charging its batteries. The maximum allowablebattery charge rate does not exceed 10% of the maximum allowable current drawn from the utility.

Modem Solid State Control Techniques Modem solid state techniques for converting from alternating to direct current and vice versa, for varying the alternating frequency and for transforming voltages are utilised to the full on each vehicle.

i(_r I Nature and Arranement of the On-Board Batteries The batteries are lead-acid units with 6 cells i.e. delivering 12 volts output: that is, normal, high-quality car batteries. Each is capable of delivering acurrent of 400 amps for 30 seconds duration.

(As and when more suitable batteries of a different type become available they may be used instead of lead-acid.) Battery output voltage falls to around 10 volts during such high current demand so this output corresponds to some 4 KW per battery. A 1 tonne vehicle requires 3 such batteries to achieve the required acceleration.

The three batteries weigh 50 Kg; i.e. 5% of the all-up weight, of the vehicle. That 5% percent figure remains constant for all vehicles powered in this manner and giving the required initial acceleration. For example, a typical Australian family car weighs around 1.7 tonnes when loaded and will need 5 batteries as above.

4 Battery output at full cruising speed (70 kph) is 100 amps. The battery can sustain this for 15 minutes at 12 volts. It corresponds to 1.2 KW per battery. Capacity is 40 amp hours per battery at the 100 amp rate. Each battery complete weighs some 16 Kg.

Note that in 15 minutes at 60 kph the vehicle will travel 15 Km. It is much to the advantage of battery life if this range is used to the full as :i: infrequently as possible. The reason for this is that the operational life of the batteries is enhanced if the maximum normal discharge is held to rather than 100%. 7 Km of travel on batteries alone results in about a 45% discharge level.

If the vehicle has to climb a hill (rather than just travel on the flat) the distance which the battery will support falls accordingly. If, for example, the vehicle has to climb 150 metres (500 feet) the maximum distance it can simultaneously travel will be approximately halved to Km.

Battery Capacity for Acceleration At the average crossing or intersection there are approximately 50 metres between the end of one power track and the start of the next. While the c battery accelerates the vehicle to 30 KPH in 4 seconds it travels metres. The full power track input energy is then available and, at KW per tonne, sufficient in the case of a car to complete the acceleration to 100 KPH in the remaining 8 seconds. The power input needed to achieve 30 KPH in 4 seconds (assuming 75% of the power is used for acceleration) is about 12 KW per tonne.

The three 12 volt batteries in full power mode provide 400 amps at volts. This is 4 KW per battery and thus 12 KW for three batteries.

This corresponds to accelerating to 30 KPH in 4 seconds and the batteries comprising 55 of total vehicle mass.

Continuous Cruising Power Continuous cruising power when on batteries is much lower approximately one quarter of that peak figure and can be maintained for as long as the battery charge lasts. This is at least 15 minutes but may be considerably longer if less power is used or if there are traffic delays. It is important to note that time spent stuck in traffic jams and the like does not use up any battery power, indeed, it allow some measure of battery recuperation. Battery Charging It is vital that this is done correctly and the necessary equipment is fitted on the vehicle. The correct charging voltage is 14 volts 0.1 volts DC per "12" volt battery. The battery must not be over-charged.

Total Weight of the Drive Train is No More than an Equivalent I/C Vehicle The total weight of the pick-up mechanism, electric motor(s) plus the battery and all control equipment in an electric vehicle is no greater than the total weight of the engine, transmission and liquid fuel in its internal-combustion-powered equivalent.

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Full Advantage is Taken of Other Benefits Full advantage is taken of the opportunities for regenerative braking, improved vehicle safety, automatic vehicle position control and collision prevention, optimum weight distribution and similar possibilities created by this system.

Regenerative Braking Current produced by regenerative barking is fed back into the utility system. The solid state controls ensure that phasing is correct and that no excess electrical or mechanical loads are created. Where there are steep hills the main supply cable is the same for both the up and the down lanes and thus.the regenerative braking input from the descending vehicles goes some way to providing power for the vehicles which are on the climb.

When a vehicle is travelling at less than 50 KPH each power track section will be turned off before it exits that section. Thus for that OFF period regenerative braking returning power to the main supply will not be available. The vehicle then relies on its conventional friction brakes. Because regenerative braking is the norm especially at higher speeds these friction brakes are of smaller dimensions and lesser weight and they experience less wear than in IC vehicles. Lane Position Control, Vehicle Separation Control and En-Route Navigation These are major human and safety benefits offered by the power track system.

Power Track can provide any or all of the following: Automatic positioning of a vehicle in the centre of its chosen lane Appropriate automatic separation of vehicles using any one lane En-Route Navigation Guidance and Alerting Automatic separation also gives the opportunity to reduce the separation between vehicles while improving safety and thus to increase the safe handling capacity of the road.

I The electricity supply lines may also be developed to convey messages to each vehicle concerning navigation, traffic disruptions, optimum routing and the like.

Metering and Payment for the Electricity Supply Vehicles pay for the electricity via a meter on each vehicle. This is essentially the same as a normal domestic meter except that it has enhanced opportunities for on and off-peak pricing and for maximum demand charging. This may be applied by location as well as by time of day or night.

Electricity Supply from the Standpoint of a Vehicle Electricity supply to the vehicle is now considered from the standpoint of the vehicle itself.

*r Each vehicle has two, strong, flexible, tubular pick-up arms. These comprise the power arm system. Each is made of glass-fibre, carbon-fibre or Kevlar, are 500 mm long and of 30 mm outside diameter.

One arm is for the live and the other for the neutral contacts. The two arms are held 360 mm apart. The neutral pick-up is towards the centre-line of the road relative to the live pick-up. Both are mounted on a square section slide bar which runs the full width of the vehicle and is affixed just below the centre-line of the vehicle. The arms are thus able to traverse the full width of the vehicle (circa 1 metre on either side of the centre of the lane) but no further. The arms have a high tensile strength.

In the optimum situation the centre of the vehicle is driving along the centre-line of the lane and thus the power arm contactor brush is running in the middle of the power track conductor while the power arm is in a central position under the vehicle.

Optional Head-Up Display Indicator As the vehicle diverges to either side of the centre line of the lane the power arm mechanism traverses across the slide bar to ensure that its contactor arms run centrally upon the power track conductors. The optional head up display on the windscreen shows the position of the vehicle relative to the lane centre line and thus aids the driver in keeping within the correct band.

Retracted Position The power arm also has a retracted position. In this position the arms swing up through some 30 degrees to lie horizontally rearwards and tuck into a channel provided in the floor of the vehicle. Thus in the retracted position, they are not exposed to damage if the vehicle "bottoms" or goes over some obstruction. Retraction is achieved by rotating the slide bar forwards through 30 degrees. Return to the seek or contact position is achieved by a rearwards rotation through 30 degrees.

This retracted position is selected automatically whenever reverse gear is selected on the vehicle. It may also be selected at will by the driver.

Retracted is the normal position when travelling outwith the utility system.

ooo The Seek Position The power arm also has a "seek" position. In this position it is partly lowered (through some 15 degrees) and is lowered fully to the contact position immediately the location detector senses that it is correctly positioned in relation to the power track.

Drivers very rapidly acquire the simple skill of positioning approximately in the centre of the lane (indicated by the power track in front of them) so that the location detector detects the lateral positioning of the vehicle is correct. Thereupon it instructs the hydraulic cylinder to lower the power arm arms into contact with the power track conductors.

The Contact Position In this position both the live and neutral components of the power arm are in steady, sliding contact with the power track live and neutral conductors. The flexibility and elasticity of the tubular arms keeps the contacts firmly together notwithstanding the up and down movement of 3 the vehicle's chassis (on both springs and tyres) relative to the road.

The mean contact force is approximately 50 Newtons for each contact.

Power Arm is Automatically Retracted when off a Power Track When apower track comes to an end when near an intersection or a pedestrian crossing) or when a vehicle diverges from the limits of a power track To change lanes or take a side turning) the location detector senses the loss of contact and raises the power arm to the "seek" position. It remains there for one minute or until the location detector again detects apower track. As soon as the location detector senses apower track in the correct position it lowers the power arm into contact. If it has not detected a power track within one minute it retracts the power arm fully until a power track is again detected. The driver may use a manual over-ride to hold the power arm in the retracted position.

Power Tracks do not Cross Intersections, Junctions or the Like Where a road has side turnings onto and/or off it the power track does not diverge along the side turning. He entering or leaving vehicle runs on its internal batteries for the short distance (circa 50 metres) between leaving the power track on one road and picking up another power track on the next road.

As described above at cross-roads and similar intersections the power tracks end some distance before the intersection and resume some beyond it. That distance is approximately 10 metres on either side of the crossing, intersection, etc.. These arrangements ensure that pedestrians or cyclists crossing the road do not have to cross apower track. Likewise it ensures that there is no interference between power tracks trying to cross each other.

Seamless Changeover from Power Track to Batteries and Vice Versa It is vital that there is a "seamless" changeover from utility supply to internal batteries when a power arm comes off apower track. This is ensured by the maximum use of modern electronic control techniques.

The batteries are capable of very high discharge currents because they will come into use especially when vehicles are undergoing initial acceleration away from the "lights".

Vehicle Design and Layout Motor Drive The location of the electric motors on the vehicle is an important aspect of this proposal. There is attraction in fitting a relatively small motor in-unit with each wheel. The problem with this is that it markedly increases the unsprung weight of the chassis thus causing both roadholding and handling to deteriorate.

The optimum solution is one motor per wheel with a short drive shaft to the wheel. The disc brake is carried in-unit with the motor. If the wheels are steered then constant velocity joints are necessary. Of course, the vehicle relies mainly on electrical re-generative braking rather than on friction braking. 0*e.

Vehicle Design and Layout Battery and Control Gear Location For cars and similar vehicles the battery location is low in the vehicle chassis and just aft of the front wheels. The forward "bonnet" of the vehicle contains the "crush zone" mainly luggage space. If the car has.

front or four-wheel drive the electric motors will occupy most of the remaining "bonnet" space.

The normal arrangement for cars is batteries, etc. At the front and two drive motors at the rear. Having one motor at each wheel eliminates the need for a differential (and, of course, the need for a transmission shaft).

It does, however, give the effect of a "differential-lock" whereby substantial drive force is maintained notwithstanding one driving wheel is slipping on boggy or icy ground.

Having at least two motors also means that the vehicle can still be driven successfully in the unlikely event that one motor fails.

The transformer and electrical control gear including the lane and separation controls is housed above the batteries. Cooling air is ducted to the transformer and the batteries by a scoop on the underside of the vehicle.

With heavy vehicles there is more choice for battery location. All-wheel drive may be used for heavy vehicles especially for tractors hauling semi-trailers. This is desirable to absorb the high acceleration torque which is available.

Vehicle Design the Power Arm Mechanism This mechanism has already been described. This concerns ensuring its safety. The hazardous components are those carrying or in contact with the high voltage current. That is to say the path from the contactor in the power track to the primary transformer winding.

The safety strategy is two fold. The first is the obvious one of heavily insulating the high voltage conductors with very tough but flexible materials. The second is to ensure that all the parts of the vehicle which might, in an accident or for any other reason, come into contact with a broken or exposed conductor are always earthed This applies particularly to the floor of the vehicle, to the slider bar which carries the pick-up arm and to the transformer body.

This is done by the critical items being bonded to each other and to the "earth return" component of the power arm. If the live component of the power arm is in contact with the live line then the "earth return" component will be in contact with the earth. Switching Sensor and Vehicle Transmitter Design and Operation The receiver for the switching sensor is located at the start of each power track section. It is embedded in the first tile at road surface level at the start of each power track section. The receiver is tuned to receive pulsed radio signals in the upper UHF band. These are transmitted to it by any vehicle about to enter the section. The incoming signals are modulated s to constitute a code. The receiver passes those pulses to the control processor for that section which validates (or not as the case may be) the incoming signal and its code.

The transmitted "beam" is some 0.4 metres wide from front to back (in the direction of the vehicle's motion) at road level and spans the full width of the vehicle. The transmitted power is of the order of a p--N illliwatt. The beam points vertically downwards towards the road.

Only one sensor/transmitter code is used throughout any national power track system. A single code may be used even across national boundaries in a unified community such as the European Union.

The controlprocessor is located adjacent to the section switch. Both are attached to and are "in unit" with the underside of the power track section. Together they constitute the control box switch which is a sealed unit in a stainless steel casing. The box lies at the middle of the section. The lane power cable which is buried in the roadway below the power track feeds into the control switch box.

If, and only if, the signal is valid power is switched to that section for seconds. At the end of 1.5 seconds the power goes off automatically.

The switch is spring loaded (and/or otherwise secured) in the OFF.

position. In the event of any failure it reverts permanently to OFF. (Note that the duration of the "1.5 second" period may be varied to suit local conditions). A fresh valid signal may be received while the power is still on from a previous signal. If so the processor determines whether the interval between the instant the power was last switched on and the arrival of the new incoming signal meets the minimum criterion say, not less than 1.5 seconds. If the interval is greater than the required minimum power is turned on for a further 1.5 seconds. If it is less then the power remains OFF. (Please note that the time intervals here described may be varied according to local conditions). If the interval between one signal and the next is less than the prescribed minimum the processor sends a multi-plexed, high frequency signal to the in-coming vehicle via the power track. If the on-coming vehicle has the "active separation" option it uses this signal to control separation.

There is further description of this process under the heading "passive and active separation" below.

The strength of the incoming signal is such that it is totally absorbed by a layer of water 5 mm deep. Thus if there is water lying to that depth on the power track it will not switch on despite a signal being transmitted from a vehicle. This ensures that if a power track becomes flooded it remains electrically OFF.

Switching Sensor and Vehicle Transmitter Design Transmitter Each electric vehicle carries a UHF radio transmitter. The radio "beam" points vertically downwards and lies across the full width of the vehicle near the front. The signal is similar to that used by remote door locking transmitters currently used on some cars. The transmitter bar has some six dipole aerial/reflectors across it. Each creates a narrow conical beam, approximately one milliwatt in power and pointing vertically downwards. The beams just overlap at the level of the road surface.

As mentioned above the beam array spans the full width of the vehicle and is some 0.4 metres in length at road level.

The transmitter is automatically turned OFF when the pick-up arm is manually retracted.

The pulses from thetransmitter carry a valid code. This has something of the form of a sophisticated but enormously fast Morse code. The code creation on the vehicle is controlled by the vehicle's key, one ROM chip and a signal from the vehicle's electricity meter. Unless a proper response is received from all four of those sources a valid transmitter code will not be generated.

If the vehicle's own key is not inserted no valid code can be created.

(Nor, in this case, will the motor controllers operate.) The meter sends a 9: stop message if it has been disconnected or otherwise interfered with. One ROM chip confirms that the vehicle is currently licensed. A new licence chip is supplied each time the vehicle licence is renewed. The chip is locked to a time signal which is multi-plexed up the power line.

Location Information and Vehicle Navigation Each power track section has a location identifier. This information is automatically passed (via a multi-plexed signal along the power line) to the vehicle. It is recorded by the vehicle's electricity meter so that charging by location (and time) is possible.

If the driver has selected navigation guidance to a particular destination the location information enables the head-up display to alert the driver to the need, say, to leave at the next exit. In turn, advice to move to the correct lane is displayed in good time.

1 i_ I~ As mentioned above a Universal Time (UTC) signal is multiplexed on the power supply and used by all vehicles so that all meters and the currency of all ROM chips run on one identical time. This time is also used to assist with navigation.

Power Track Roads are Compatible with Conventional Road Vehicles This Power Track system does not inhibit conventional i/c powered vehicles using the roads in conjunction with electric ones. It may be (especially in urban areas) that when the proportion of electric vehicles reaches a substantial level then legislation will be enacted to exclude i/c vehicles totally (other than defined emergency vehicles) from a designated area. This will ensure that the full environmental benefits are attained for that area....

Installing Power Track in Existing Roadways The procedure for installing a Power Track system in an existing roadway begins with a survey of its drainage. Good drainage is a prerequisite for a power track installation. Next the provision and layout of the electricity supply cables needs to be surveyed and planned. Both the surface water drains and the electric cables need a matrix of shallow trenches in the road. o When that has been done the installation of the power track sections is quite simple. The concrete bearer tiles (1,000 mm x 600 mm a 60 mm deep) are set 30 mm into the road surface. Twenty such tiles constitute one power track section. Each section is electrically isolated from its adjoining sections. The first tile in each section has the section sensor and the section controlprocessor and section switch built into it as a sealed unit. On the underside it carries the gland into which the incoming power cable is inserted, locked and sealed.

The conductor is 1 mm deep by 200 mm wide and is bonded by an epoxy adhesive to the top of each tile. The conductor is 400 mm shorter than metres so that a 400 mm electrically-isolating gap is left between each power track section conductor.

Tiles may be exactly square in section or may have 1, 2, 3 or 4 degree ,,angles across one end. This permits the power track to turn through up to 80 degrees in a running distance of 20 metres. Normally curves will be much more gentle and will call for only a few tiles to have even a 1 degree angle. The conductor is quite flexible so that it can readily accommodate such curves and also the climb and descent oftheroadway.

Maintaining a Power Track System Daily Every day (or at whatever other interval local conditions dictate) each power track lane and the adjacent road surfaces are brushed and vacuumed. This ensures that the system remains in good condition and helps to ensure free flow oftraffic. It is done by a specialist machine which can operate autonomously.

Maintaining a Power Track System Major Refurbishment It is vital that all the components of the system have very high reliability in the first place. Design life of a power track section, its sensor and its switch control box is 108 cycles of use. With a high average traffic density of 10,000 vehicles per day this gives a 10,000 day life, that is, some 27 years.

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The design is such that ifa component does fail, say a sensor or a switch, it fails safe. That is to say the section in question remains "dead" until the whole lane is refurbished. Even 10% of sections "dead" present no significant problem to traffic. However, in normal course any defective sections are replaced as part of routine, scheduled maintenance.

When the overload switch to apower track has cut off power and re-closures have not been successful (say, due a deliberate short having been created by vandals the circuit-breaker may be re-set from the surface using a coded signal. This enables the main power supply to initiate the re-setting process. Of course, this only re-setting the circuit-breaker. The power track section remains OFF unless and until a valid coded signal is received by its sensor.

System Needs Massive Public and Private Investment It is obvious that such a system will need massive private and public investment. Fortunately the economic justification for the investment is highest where traffic is most dense: that us to say in urban areas, on motorways and on other busy roads. Still more fortunately these areas are exactly where the environmental need and benefit are also greatest.

Existing I/C Vehicles can Readily be Converted to Use a Power Track Conversion to a Power Track system is markedly assisted by the fact that existing i/c engined vehicles may readily be converted to use power track supply. In summary an electric motor plus the power arm replaces the engine, the batteries take the place of the normal battery and the fuel tank(s), the clutch/gearbox becomes redundant and is replaced by the transformer, meter and control gear and the vehicle transmitter is added.

Total weight and weight distribution are substantially unaltered.

Change-over is PRE-planned on a "lift-out and drop in" "kit" basis and takes no more than one day. 9999 The resulting vehicles are not optimised as electric vehicles but they perform in a satisfactory manner. 9 99* :g Safety Issues and Problems •r Safety is the major consideration. The system must be safe, first and foremost, for other non-vehicle borne road users; pedestrians, cyclists and even stray animals. The principal danger is of accidental (or possibly even suicidal) electrocution.

Happily the system offers many improvements to safety as well as potential hazards. These improvements are touched on later. First the potential hazards are considered.

Possible Electrocution The danger of accidental electrocution is essentially eliminated by the arrangement whereby the conductors are only "live" for a very short interval after receiving a vehicle sensor signal. This means that a power track section is live only when a vehicle is effectively on top ofit.

77System reliability in this respect is vital and it is continuously monitored.

The power track also makes deliberate attempts at electrocution very difficult, albeit not impossible. For those bent upon suicide it is much easier to throw themselves in front of a heavy vehicle than to arrange electrocution using apower track.

Power Tracks end near Critical Areas for Pedestrian and Cyclist Safety For both pedestrians and cyclists the fact that there are no power tracks, live or otherwise, within 10 metres either side of any road or pedestrian crossing eliminates much of the perceived as well as the actual hazard.

Likewise power tracks may not be allowed in housing areas, adjacent to shopping centres or any similar locationswith substantial pedestrian movement. Vehicles use their internal battery power to negotiate those areas. As noted earlier use of batteries creates an automatic "traffic calming" effect. In addition the vehicles are almost silent.

0O 1; Those on foot who choose to cross the road at random points will, as a matter of common sense, not place their feet or hands on the live power tracks. However, even if they do so no harm can come to them unless they elect to do it immediately in front of an on-coming vehicle. In :1 that event it is possible they will be electrocuted some milliseconds before they are flattened by the vehicle. *00e one* Safety for Animals Animals (whether in city or country) who cross the road for their own reasons will similarly face no hazard and no impediment from the power tracks except in the eventuality described immediately above.

Safety for Cyclists and Motorcyclists Normally cyclists will not be cycling out in the middle of a lane.

However, some roads are in such a condition that cyclists hardly have any option. Thus roads with power tracks should also have adequate cycle ways provided on those roads. Cyclists who have to go to the centre of the road at intersections (to turn right in Australia or left in USA) still face all the hazards that this entails. However, they do not require to beware ofpower tracks because none are fitted across Sintersections.

Both cyclists and motorcyclists need to be aware that the sides of the power track sections will be slippery in wet conditions. This applies with more force to motorcyclists who will regularly cross power tracks in normal riding.

Protection against Vandalism Another hazard is deliberate vandalism which attempts to short out the conductors by placing a metal rod across apower track, etc. Again the "no coded signal no power" and "power off in 1.5 seconds" arrangement provides good protection.

The system does not prevent one person driving a car to activate apower track section while a colleague outside the car simultaneously tries to short out the section. ,One can feel little sympathy with those who do themselves a mischief while indulging in such premeditated vandalism. However, the damage they can do to the power track system is limited to putting single sections out of commission until they are repaired. The effect on users of the system of individual power track sections being inoperative is negligible.

Similar considerations apply to other vandalistic activities such as covering a power track section with stones, bits of metal or whatever. If a power track section is thus covered the power arm will merely push the obstruction aside and make contact again as soon as the uncovered part is reached. There will be negligible impediment to traffic. The obstruction will be apparent to the on-coming drivers. They can report it by mobile phone or whatever or it can be left to be cleared by the cleaning machine on its next round.

Similar observations apply if vandals burn, try to chop up or otherwise destroy apower track section. If the attempted damage is successful that section or sections will be innocuously out of action until it is repaired. Traffic will flow normally.

Traffic Accidents In the event of an accident electrical safety is assured by the fact that the power supply is always automatically cut off 1.5 seconds after the F vehicle enters the section. In the event of a cascading rear end shunt the last vehicle to arrive in the section (and hit the back of the pile-up) may also restore power for a further 1.5 seconds. In such an event it obviously behoves all on the scene to stay well clear of the power track until the crash is complete. (That will also help prevent them being mown down by the oncoming vehicles.) It is also possible that a broken piece of metal on one or more of the vehicles will lodge on the power track and thus render the entire metal bodies of the vehicles live. This condition will cease 1.5 seconds after the last vehicle joins the pile-up. The vehicle body being "live" will do no harm to the occupants unless they step from the vehicle onto the ground while this condition persists. The safety rule in a crash, therefore, is "don't leave your vehicle until at least 1.5 seconds after the last vehicle has joined the crash.

Need to Wash Down any Battery Acid Spill Thoroughly In the event of an accident which results in any spill of battery acid it is vital that the area is thoroughly hosed down to remove this potential cause of electrical leakage before the lane is restored to use.

If any material which is liable to make water conductive (such as salt, fertiliser and so forth) I spilt anywhere on the roadway it is vital that this is thoroughly flushed down into the drainage system. If not there will be current leakage and possibly a serious short as and when the next rain falls. Heavy Rain During heavy rain the drainage system is more than sufficient to carry the resultant water away from the power track sections. The exception to this is if the entire drainage system becomes overfilled. This brings about a flooded condition which is further discussed below.

Because rainwater is essentially distilled water it has minimal electrical conductivity and the surfaces of the power track being wet gives rise to no significant electrical leakage problem. If a salt or an acid is present in substantial concentration the situation is quite different. (See above.) It is thus vital that any salt or other conductive material is thoroughly removed in the event of a spillage.

Flooding If a section of road is liable to be flooded periodically then that section is treated in the same way as any other discontinuity (such as an intersection) and power tracks are not laid there. Vehicles must negotiate it by momentum or use of their batteries. Roadside notices will give warning of this need.

In very heavy rain on a section which does not regularly flood the road drainage system may become temporarily overloaded and the power track filled with water. The advice to drivers in those conditions is to retract the pick-up arm and drive through the flooded section on their batteries. No doubt some drivers will fail to follow this advice. In that case the "insulating effect" of the water depth over the radio sensor will come into play and the vehicle's signal will fail to turn the power track on.

Snow and Ice If the power track on a road is covered by a layer of snow or ice it will not operate. This is because the vehicle's signal will not be received by the in-road sensor and because the power arm will not be able to contact the power track. When a heavy fall of snow (including snow drifts) has closed a road it must be ploughed clear. When this has been done the snow or ice remaining on the power track is "melted-out" by a trace heater line. This is fitted in areas subject to freezing conditions and may be turned on from the central control panel. It is electrically powered at low voltage and is independent of the electrical supply to the power track itself.

It is important that the power track installation is smooth and low on the road surface so that it is not liable to be damaged by a snow-plough.

The power track is designed accordingly. Snowploughs for use on a power track road must have a rubber fillet on the underside of the plough and this must be kept in good condition.

Where light snow is falling and/or freezing conditions exist the heat generated by normal use of the power track is more than sufficient to keep it clear of snow or ice.

Salt Must Never be used on a Power Track Use of salt or similar materials to melt snow or ice on a power track road is forbidden. If salt or the like is spilt it must be thoroughly dissolved away by hosing before traffic resumes.

Red Warning Lights may show when a Power Track Section is ON As an additional precaution for those who choose to "dodge" across a road between lines of slow moving traffic and thus may come upon a live power track section small red warning lights may be fitted on each side of the section at, say, 5 metre intervals. These flash red when the power track section is live.

Enhancements to Safety No Flammable Fuel The most obvious enhancement to safety with an electric vehicle is that it does not carry a load of highly flammable fuel. This largely eliminates the risk of fire in the event of an accident. This enhancement will only be attained fully as and when no petrol-using or gas-using vehicles are on apower track road.

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Lane Control Most multiple-fatality accidents involve vehicles diverging out of their lanes and either hitting other vehicles head-on or running into trees, ravines or other traps by the roadside. The power track system offers "cruise-control" as in conventional vehicles. It also offers "lane control". This is a by-product of the power arm facility. This is monitoring (and displaying) the position of the vehicle in relation to its lane in any event and the resultant output can, with minimal additional equipment, be used to automatically adjust the steering to keep the vehicle within, say, 0.5 metres either side of the lane centre line.

As with cruise control, lane control can be selected or unselected by the x driver at will. Lane control is automatically deselected whenever a _~1 vehicle leaves a lane. The status of both cruise control and lane control is shown on the head-up, windscreen display.

Lane control requires the vehicle to have power steering. As a vehicle starts to diverge from the centre of a lane small and proportionate correcting inputs are mode to the power steering jack. As and when a road is all-electric "lane control" will go a long way towards totally eliminating these, the worst kind of accidents.

Passive Vehicle Separation Another cause of major pile-ups in some countries is fog. This applies especially to randomly drifting for patches which quite often beset motorways in the UK for example. The resulting multi-vehicle smashes are spectacular and very disruptive to traffic. They do not, usually, involve so great a death toll as head-on crashes.

To eliminate this problem and others power track offers "separation control". This can be either passive or active separation. Passive control is standard. The power track sensor and switching mechanism sets a minimum interval between receipt of vehicle signals (say, seconds) for a signal to be valid. If a signal is received less than, say, seconds after the previous signal the power to the section in question is not switched on. Thus the following vehicle has to use battery power. This is less powerful than the power track supply and so the vehicle tends to drop back to a minimum of 1.5 seconds (or whatever) separation.

Of course, such separation can be set at whatever level the proper authorities determine. Because the response is automatic the separation interval can be prudently set at a significantly lesser figure than is required when depending on driver reflexes alone. A lower figure than 1.5 seconds may be appropriate on urban feeder roads at peak hours. By the same token a greater separation interval may be appropriate on the fast lanes of motorways.

For so long as both I/C and electric vehicles are using the same road it may be well not to make the automatic separation interval too great as to do so may encourage thrusting drivers of I/C vehicles to dart in and "fill the gaps".

_I I Active Separation Passive separation will not work on a downhill stretch where the grade is such that vehicles gain speed without power input from their motors.

This can be provided by-"active" separation.

With active separation the processor in each power track section measures the interval between vehicle arrivals as for passive separation.

However, the resultant information is passed to the vehicle in question by a high-frequency, multi-plexed signal via the power track section and the vehicle's power arm. If the interval is less than is needed for the required separation regenerative braking is applied for a short period to re-establish the required separation. The intensity of the braking force applied is proportional to the amount by which the actual interval is less than the required interval. If necessary the friction wheel brakes can be invoked also.

It is evident that on an electric-only road using the power track system the "holy grail" of safe automatic driving lies readily to hand with minimal additional equipment or expense. Of course, the driver is still essential to negotiate junctions, crossings, housing areas and all other places where there is no power track 4= i Location Information and Navigational Guidance As mentioned earlier each power track carries its own location code and transmits this to each vehicle which comes into contact. For those whose vehicle has the navigation option and who are unfamiliar with the area in which they are driving this location information can be integrated with a destination entered by the driver. In this mode the vehicle's computer invites the driver to select a route or determines the optimum route itself.

When the route has been entered the head-up display advises the driver of his or her location on a small "moving map". This shows each upcoming turnoff and the like. It does so in ample time to allow the driver to be in the best lane to carry out the manoeuvre. The nay option may include a voice alert; e.g. "Turn left onto Mamre Road 1 km ahead.

Then turn right at the intersection and head north." Those Living Permanently More than 10 Km Outwith a Power Track Supply In countries such as Australia and North America there are rural areas which are geographically very large but which have very low population. In such areas there is no realistic prospect of a power track system ever being laid. The answer here is probably that people in such areas continue indefinitely to use conventional I/C vehicles. In so far as those vehicles are, by definition, few in number and spend most of their time in sparsely populated areas that presents no great environmental problem.

Those vehicles which have to go a considerable way off the power track system (say, 100 200 Km) but also make frequent use of urban areas the solution is an optional diesel charging power pack. This power pack is on a compact trailer. Typically it is 10 to 20 KW in power and feeds into the DC side of the vehicle's control panel. In use it provides both modest cruising power and, when necessary, some battery recharge. It runs at a constant speed with the torque varying according to the electrical demand from the vehicle. Secure trailer parks are provided at rural entry points to the power track system and many drivers making the round trip elect to drop offtheir trailers in the park and collect them on their way back from the city.

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Claims

1. The objective of the invention is to provide a total system which enables the practical and universal use of electrically-powered road vehicles of all types and sizes which are similar in weight, performance and cost to their IC-engined equivalents and which are compatible with all types of conventional vehicles also using the road. The system may be installed on one, some or all lanes of a new road or of any existing sealed road. Only a conductive system of power pick-up (as opposed to an inductive system) is able to transfer sufficent power at sufficently high efficiencies to attain those ends. To make a conductive system safe and practicable in all conditions, including times of heavy rainfall, the following elements of the system are essential: A medium-voltage electricity supply on the road surface. The supply is provided by copper strips (typically 20 metres long, 200 millimetres wide and 1 millimetre thick) laid upon special tiles. There are typically 50 such sections per kilometre of road lane. Each section length is electrically isolated from adjacent sections. Power to each separate section comes from underground mains. Section lengths will be shorter in areas where traffic may move slowly. The conducting copper strip is bonded along the top of special tiles. Each tile is approximately 1 metre long, 0.6 metres wide and 60 millimetres deep. 20 such tiles laid end to end constitute one 20 metre long section. The tiles are set 30 millimetres into the road surface and thus stand 30 millimetres above it. The sides of the tiles slope down to the level of the road. The first and last tiles in a section do likewise where they abut the adjoining sections. The sloping faces have a high-gloss, hydrophobic finish so that they shed water effectively and thus minimise electrical leakage during wet weather or other damp conditions. Each section is entirely surrounded by a neutral/earth metal strap to ensure that electricity cannot leak beyond the confines of the section. The insignificant height of the tiles permits wheeled traffic, pedestrians and animals to pass over them without obstruction. The fact that power is OFF unless a vehicle is effectively on top of the section obviates the danger of electrocution. Power to each section is controlled by a switch activated by a UHF radio receiver located at the start of that section. The normal condition for each section is power OFF. Power comes ON only when the receiver detects a valid signal code and is ON oly for a very short time (approximately 1.5 seconds.) i*n remains OFF until another coded signal is received. Each electric vehicle carries on its front a low-powered UHF transmitter which sends out a signal which is received by the section receiver immediately in front of it. If the code is valid power to that section is switched ON for approximately 1.5. seconds. That is, for approximately the time during which the vehicle is passing over the section. In the absence of a signal the power to the section remains OFF. As the vehicle travels along a road successive sections come momentarily ON as required and then return to OFF. A retractable pick-up and return arm assembly is fitted to the underside of each electric vehicle. This enables it to draw electric power from a section which is ON. One (heavy) vehicle may draw up to 400 KW from a section. The pick-up assembly may slide from side to side across the width of the vehicle. 0*Q 0 A magnetic sensor fitted to each electric vehicle detects its position in relation to the centre line of its traffic lane and uses that information to adjust the lateral position of the pick-up arm assembly so that it is always centred upon the on-road power conductor. The on-road power supply is stopped shortly before discontinuities such as crossings or intersections or in areas of heavy pedestrian traffic such as housing or shopping areas, schools and like locations. To enable electric vehicles to negotiate those areas each is fitted with a small bank of lead-acid batteries. These do not exceed 5% of the all-up weight of the vehicle. They provide a cruising range of not less than 10 kilometres and enable an electric vehicle to accelerate satisfactorily over crossings and the like. Industry-standard solid state control devices ensure "seamless" changeovers from road supply to batteries and vice versa. Industry-standard devices both on the vehicle and within the road supply sections suppress electrical sparking as the vehicle leaves one section and enters another. The batteries are automatically kept fully charged whenever the vehicle is using a power track supply. They can also be recharged at domestic or other static points.

2. As an option the information feedback provided by the system may be used to control motor power, regenerative and/or friction braking and steering to give both passive and active control of an electric vehicle's position within its traffic land and distance separation from the vehicle in front.

3. As an option the onboard equipment needed to enable an electric vehicle to use this system may, optionally, be fitted in kit form to convert existing IC-engined vehicles to use this system. An electric motor takes the place of the previous IC-engine. -Vehicle weight and performance are largely unchanged. *o a a a a a a a a a.. a