WO1992009447A1

WO1992009447A1 - Hydro electric vehicle drive system

Info

Publication number: WO1992009447A1
Application number: PCT/GB1991/002074
Authority: WO
Inventors: Dominic Wickman
Original assignee: Dominic Wickman
Priority date: 1990-11-24
Filing date: 1991-11-22
Publication date: 1992-06-11
Also published as: JPH05505509A; GB2250726A; GB9025609D0; GB2257098B; AU8919191A; GB2250726B; EP0512086A1; GB9216086D0; GB2257098A

Abstract

A hydraulic drive system for powering a vehicle comprising: a fluid circuit; a battery driven motorised pump operable to circulate fluid around said fluid circuit; a turbine-generator operably associated with said fluid circuit to generate hydro electricity; and a drive motor for driving the vehicle connectable to the turbine-generator to be powered by the hydro electricity. The drive system may comprise an automatic switching system for enabling change over from charging of a first set of batteries and discharging of a second set of batteries to charging of the second set of batteries and discharging of the first set of batteries when the first set of batteries has charged above a predetermined level or the second set of batteries has discharged below a predetermined level.

Description

HYDRO ELECTRIC VEHICLE DRIVE SYSTEM

Field Of The Invention

A hydro electric drive system for powering a vehicle.

Review Of Most Relevant Prior Art Known To The Applicant

δ With the escalating price of petrol and increasing public concern over ecological issues the pressures to develop an effective alternative to the internal combustion engine for powering vehicles are evermore great. The option of using battery power to drive a vehicle has long been appreciated as exemplified by the electric

10 driven milk float or invalid car. However, battery powered vehicle drive systems have largely been confined to such specialist vehicles and the broader potential of the electric vehicle drive system has yet to be realised. The prime reason for the slow development of the electric powered vehicle is the simple physical lδ constraint of the low power storage capacity of batteries capable of delivering adequate power performance. A milk float, for example requires a multitude of 12 volt lead acid batteries to sustain it through a 3 hour delivery run at an average speed of less than lδ mph. To mitigate the problem of low battery power

20 storage capacity various techniques of power recovery to recharge the battery have been developed. Beyond the well known technique of using sunlight falling on solar panels to recharge a drive battery, use of wind driven turbines mounted to the vehicle or axle-mounted dynamos are popular energy recover options. A number of battery powered vehicle drive systems make use of a hydraulics circuit to multiply the driving forces from an electric motor. Example such systems are described in FR- 2441741 and DE-A-2404809. These known drive systems each comprise a δ hydraulic press coupled to the vehicle drive axle.

To the best of the applicant's knowledge no known systems make use of a fluid circuit between a first battery driven motor and a second motor powered by hydro electricity. Furthermore, each known hydraulic system does not recover energy from its 10 hydraulic fluid circuit to recharge its battery. The battery is recharged by conventional means such as use of an axle mounted dynamo or a wind driven turbine.

Summary Of The Invention

A hydraulic drive system for powering a vehicle comprising: A Iδ fluid circuit; a battery driven motorised pump operable to circulate fluid around said fluid circuit; a turbine and generator operably associated with said fluid circuit to generate hydro electricity; and a drive motor for driving the vehicle connectable to the turbine-generator to be powered by the hydro electricity.

0 Preferably one or more further turbine-generators are provided, operably associated with the fluid circuit to generate hydro- electricity.

Preferably the one or more further turbine-generators are used to recharge the one or more batteries which power the drive system, δ in use.

Preferably the fluid circuit incorporates shunts which may be opened and shut by electrically powered flow valves to isolate one or more of the turbine- generators from fluid flowing within the circuit. Advantageously more than one battery is provided and an automatic switching circuit is provided to control alternation between charging and discharging of each battery.

Preferably three batteries are provided, two of which alternate δ between powering the motorised pump and being charged by one or more turbine-generators, and a third battery which powers the automatic switching circuit.

Preferably the automatic switching circuit is composed of relays. Advantageously, automatic switching circuits may be provided to 10 enable the drive motor or a separate axle mounted dynamo to generate electricity for recharging the one or more batteries.

In the second aspect of the present invention there is provided an electric or hydro electric drive system for powering a vehicle which comprises an automatic switching system for enabling lδ change over from charging of a first set of batteries and discharging of a second set of batteries to charging of the second set of batteries and discharging of the first set of batteries when the first set of batteries has charged above a predetermined level or the second set of batteries has discharged below a

20 predetermined level.

Also within the scope of the present invention is a vehicle incorporating the drive system according to the first or second aspect of the present invention.

Brief Description Of The Drawings

2δ A pre!f _.n _4 €ynbodt ent will now be more particularly described by way of example and with reference to the accompanying drawings wherein figures la- If collectively comprise an electro- mechanical circuit diagram of a drive system embodying the present invention. The ends of lines extending to the edge of each sub-

30 figure match up with corresponding lines on the edge of an adjacent sub-figure. The bottom edge of figure la matches with the top edge of figure lb, the bottom edge of figure lb with the top edge of figure lc, the left hand edge of figure lc matches with the right hand edge of figure Id, the top edge of figure Id δ matches with the bottom edge of figure le, the top edge of figure le matches with the bottom edge of figure If, and the right hand edge of figure If matches with the left hand edge of figure la.

Description Of Preferred Embodiment

Referring to figure lb the heart of the drive system comprises a 10 fluid circuit 100 through which water containing anti-freeze, or another suitable fluid or fluid mixture, flows in use. The fluid is circulated around the circuit 100 by a motorised pump 1. A primary turbine- generator 1 and an auxiliary turbine-generator 2 are positioned in the path of fluid flowing through the circuit 100. Iδ Each turbine 1, 2 may, however, be isolated from the flowing fluid by a respective bypass shunt 100a, 100b under flow valve control. Flow valves 1,3 direct flow through these bypasses 100a, 100b when activated by respective relays. A pair of pressure release valves δ, 6 are also incorporated in the fluid circuit 100.

20 Referring to figure lc, the output from the primary turbine- generator 1 is fed to a drive motor 2 which is mounted to the carden shaft or one of the wheel axles of the vehicle. Drive motor 2 is switched on at a relay 12 when the current of hydro electricity generated by the turbine- generator 1 exceeds a δ predetermined level set by a resistor, preset 3. A power controller

Pc 2 controls the speed of motor 2 by varying the power supplied by turbine-generator.!. A further relay, 13, and preset, 4, are provided to enable the drive motor 2 to be switched from being driven to acting as a dynamo to recharge one of the batteries.

0 Also shown in figure lc are a further pair of relays 9, 11 one of which, relay 11, switches between contacts enabling drive motor 2 to charge one of the batteries, and the other of which, relay 9, alternately switches on valves 3 and 4 to control isolation of turbine-generator 1. -o-

Referring to figure la, a relay 3 and preset 1 are provided tc channel hydro electric current from the turbine- enerator 2 tc a battery for charging when current flow from the turbine- generator 2 exceeds a predetermined level. A further relay, relay δ 2, is provided to switch between operation of flow valves 1 and 2 to direct bypass flow around turbine- generator 2. A third genei-ator, generator 3, may be used to recharge the batteries in place of turbine-generator 2 by action of relay coils la, lb and lc. Generator 3 is an axle-mounted dynamo such as that used to

10 recharge the battery of many combustion engine driven vehicles.

Figure If illustrates the three batteries used to power the drive system. Batteries A and B are used alternately to power the motorised pump 1 and are alternately recharged by turbine- generator 2, generator 3 or drive motor 2. The relay circuitry lδ used to control automatic changeover between charging of one battery and discharging of the other will be described in more detail herein after. The third battery, battery C, powers all of the relays. To avoid over complicating the circuit diagram lines extending from the relays to battery C are simply labelled with

20 the letter C. When the drive system is not in use batteries A, B and C may be isolated by respective isolator switches s9, s7 and s8.

Operation of the drive system illustrated in figures la-lf will now be described in more detail.

2δ Before starting up the motorised pump 1 switches si, 2, 3 and 4 are all in the off state as illustrated. Switches 6, 7, 8 and 9 are in the on state. To initiate circulation of fluid around fluid circuit 100 switches εl and ε2 are switched on. These two switches si and ε2 are linked by link 1 to operate together but

30 can be operated independently if desired. Making contact across switch 2 conducts power from battery C to relay 11 which in turn connects motorised pump 1 to battery B. Making contact across switch 1 powers relay 9 to close flow valve 3 and open flow valve 4 directing flow via generator-turbine 1. Under some circumstances it may be desirable to operate switch 2 prior to switch 1 to enable build up of flow through bypass 100a prior to directing flow via generator-turbine 1. Switch 4 being off, relay 2 is off and hence valve 1 is closed and valve 2 is open (the flow δ valves open under power). Bypass shunt 100b is inoperative and thus circulatory flow passes through the path of generator- turbine 2.

The fluid pumping rate is controlled by power controller Pc 1 which varies the power supplied to the motorised pump 1. This 10 power controller may, alternatively, be sited between motor 1 and pump 1 components of the motorised pump 1.

As the fluid within fluid circuit 100 gains momentum the hydro electricity generated by generator-turbines 1 and 2 will increase above predetermined levels set by preset 3 and 1 respectively. lδ Current thus flows from turbine-generator 1 to power drive motor

2, and from turbine-generator 2 to charge battery A.

As drive motor 2 sets the vehicle in motion, the axle mounted dynamo, generator 3, will begin to generate electricity. With switch 6 in one position this electricity may be directed to 0 recharge one of the batteries, A, B or C. With switch 6 in its other position the electricity may be directed to some alternative load, such as for example the vehicle headlights, indicated as generator 3 load on figure la.

Switch δ enables a selection to be made between use of the power 5 output from generator 3 to charge battery A when switch sδ is in its position N, or to charge battery C when switch δ is in its position CH. With switch δ in position N relays lb and c are powered whilst relay la is not. When powered relay lb puts the axle-mounted generator 3 to charge battery A and relay lc puts 0 the auxiliary turbine generator 2 to charge battery C. Switch sδ in its CH position powers relay la alone enabling relay lb to switch turbine- generator 2 to charge battery A while relay lc changes battery C to relay la contacts. Since relay la is now powered this switches the axle mounted generator 3 to charge battery C. The overall result of this arrangement is that with switch δ in position rl (normal) battery A or B will be charged by generator 2 until generator 3 operates. Generator 3 will then cause generator 2 to be switched to charge battery C while δ generator 3 charges battery A or B. If desired generator 3 can be used to charge battery C and generator 2 to charge batter;- A or B by setting switch sδ to its CH position.

As the vehicle moves along, the momentum gained by the axle- mounted drive motor 2 can be made use of to generate electricity

10 for charging battery A or battery B. If switches 1 and 2 are moved to the off position relay 11 will switch off. Hydro electricity will cease to be generated relay 12 will switch off, drive motor 2 will be able to generate electricity and, by tripping relay 13, this electricity will be conducted back to whichever lδ battery, A or B, was powering the motorised pump 1 immediately prior to turning off switches 1 and 2.

An automatic changeover circuit (figures Id, le and If) is provided to enable battery B to be charged as soon as it has discharged below a predetermined minimum voltage or as soon as

20 battery A has charged above a predetermined maximum voltage.

Similarly, the automatic changeover circuitry will subsequently reverse the order of charging and discharging when battery B charges above the predetermined maximum level or battery A discharges below the predetermined minimum level. The maximum

2δ level of charging and the minimum level of discharging are, respectively, responded to by a charge monitor comprising, in part, a relay 6b and preset resistance, preset 6, and a discharge monitor comprising, in part, a relay 6a and a preset resistance, preset 7. When switched, relay 6a or 6b will trip a further relay,

30 relay 4, to switch the output from the generators 1, 2 or 3 and the load from the motorised pump 1 between batteries A and B.

When the drive system is initially turned on and battery B is discharging to the motorised pump 1 and battery A charging^* from generators 1, 2 or 3 relay 4, will be unpowered, as illustrated. The power is supplied to relay 4, from battery C when a further relay, relay 10b, which is initially powered by battery B, switches off as a result of battery B discharging below the predetermined level set by preset δ. or when a further relay, relay 10a, switches δ on as a result of battery A charging above the predetermined level set by preset 8. Power is supplied to relay 4 and two further relays, relays δ and 8, from Battery C via a latching relay, relay 7 which is activated (powered) by deactivation of relay 10b or activation of relay 10a. Following activation of relay 4

10 Battery B will begin to charge while Battery A begins to discharge. Activation of relay δ connects battery B via preset 6 to relay 6b and disconnects battery A from preset 8/relay 10a. Activation of relay 8 connects preset 5/relay 10b to battery C to maintain relay 10b in the activated state. Relay 8 also disconnects lδ preset 7/relay 6a from battery C and reconnects them to battery

A. When battery B has charged sufficiently to overcome preset resistance 6 relay 6b will be activated switching back relay 4. Alternatively, when battery A has discharged below the level set by preset 7 relay 6a will be deactivated also switching back reiay

20 4. Either of these occurrences will result in resetting of battery A to charge and battery B to discharge.

To avoid false switching of relays 6a and 10b, these relays are each fitted with a capacitor, C2 and Cl respectively, to smooth power surges and provide temporary power supply should power 5 from the battery be cut. Capactior C2 maintains power to relay 6a as relay 6a is transferred from battery C to battery A.

Should it be required to change over charging and discharging of batteries A and B manually, a suitable switch S3 is provided.

Although the present invention has been described above with 0 respect to one preferred embodiment numerous alternative embodiments are possible. Although the circuit of the drive system illustrated is composed of a large number of relays, the same role may be performed, less efficiently, by solid state circuitry. It has been found in practice, that integrated circuits are an unreliable alternative to relays.

Although the turbine-generators referred to herein- above may be of conventional design comprising a turbine module and a generator module interlinked by some form of transmission such as a drive shaft or belt, the turbine and generator may be formed integrally. Higher efficiency of operation may be obtained through eliminating the need for a transmission between each turbine impeller and associated generator rotor. In such case the turbine impeller is integral with the rotor of the generator. One design of turbine-generator illustrating this arrangement is depicted in Figures 2-4.

Figure 2 is a schematic longitudinal sectional view of a turbine-generator.

Figure 3 and Figure 4 are transverse sectional views of the turbine-generator shown in Figure 2, taken along the lines III-III and IV-IV in Figure 1, respectively.

Referring to Figures 2-4, the turbine-generator comprises a casing 1 within which an integral impeller/rotor 20 is rotatably mounted by suitable end bearings 21, 22. The impeller/rotor 20 comprises a longitudinally extending axle 23 around which the rotor windings 24 are wound. One, or preferably more, impeller blades 35 are mounted extending radially from the axle 23 and are bent part-way along their length such that a portion thereof extends substantially parallel to the axle 23.

The windings 24 are connected to slip-rings 25 at one end of the axle 23. The slip rings 25 are connected by bushes to an external point of connection 26 to which power is supplied by a suitable source (not shown) to enable energisation of the rotor windings to generate magnetic flux.

Stator windings 27 are wound around casing members 28. These casing members 28, in turn, are mounted around an inner cylindrical casing 29 which longitudinally surrounds the combined rotor/impeller 20. Together with a longitudinal end wall 36 and a grill 31 at opposing ends of the axle 23 the cylindrical casing 29 forms a chamber 30 encompassing the rotor/impeller 20 into which fluid may flow and out of which it may exit, via the grill 31.

An external end portion 32 of the casing 1 housing the turbine-generator is adapted as shown in Figure 3 to provide an inlet port 33 and outlet port 34 through which fluid may flow and arranged in such a manner that a vortex of the fluid is created within the chamber 30.

Fluid from the fluid circuit of the vehicle drive system enters the turbine-generator through the inlet - port 33 tangentially to the casing 1 and swirls upwardly through the grill 31 and up through the chamber 30 to turn the impeller/rotor 20. The fluid then exits via the outlet port 34. The manner in which the vortex is created may be by a variety of arrangements known in the art.

The vortex causes a high rate of rotation of the rotor/impeller 20 which, when the rotor is energised, creating magnetic flux, cuts the magnetic flux and generates hydroelectricity in the stator windings 27.

Where the motive fluid in the circulatory system is a liquid, especially, the liquid is desirably a super- insulating liquid to prevent losses from the rotor or stator through the liquid.

The term hydroelectricity as used throughout this specification includes electricity generated by flowing gaseous,as well as liquid,fluids.

KEY TO REFERENCE NUMERALS USED IN FIGURES la-If

1 pump 1 2 motor 1 3 primary turbine 1 4 primary generator 1 auxiliary generator 2 6 auxiliary ur ne. 2 flow valve 1 flow valve 2 flow valve 3 flow valve 4 flow valve 5 flow valve 6 tank 1 drive motor 2 relay la relay lb relay lc relay 2 relay 3 relay 4 relay 5 relay 6a relay 6b relay 7 relay 8 relay 9 relay 10a relay 10b

relay 11 relay 12 relay 13 generator 3 generator 3 load

Claims

CI.ATMS

1. A hydraulic drive system for powering a vehicle comprising: A fluid circuit; a battery driven motorised pump operable to circulate fluid around said fluid circuit; a turbine- generator operably associated with said fluid circuit to genei'ate hydro electricity; and a drive motor for driving the vehicle connectable to the turbine- enerator to be powered by the hydro electricity.

10

2. A drive system according to claim 1, wherein one or more further turbine- generators are provided, operably associated with the fluid circuit to generate hydro-electricity.

lδ 3. A drive system according to claim 2, wherein the one or more further turbine- enerators are used to recharge the one or more batteries which power the drive system, in use.

4. A drive system according to claim 2, wherein the fluid

20 circuit incorporates shunts which may be opened and shut by electrically powered flow valves to isolate one or more of the turbine- generators from fluid flowing within the circuit.

δ. A drive system according to any preceding claim, \\. herein

25 more than one battery is provided and an automatic switching circuit is provided to control alternation between charging and discharging of each battery.

6. A drive system according to claim δ, wherein three batteries

30 are provided, two of which alternate between powering the motoi'ised pump and being charged by one or more turbine- generators, and a third battery which powers the automatic switching circuit. - li -

7. • A drive system according to claim δ or claim 6, wherein the automatic switching circuit is composed of relays.

8. A drive system according to any preceding claim, wherein δ an automatic switching circuit is provided to enable the drive motor or a separate axle mounted dynamo to generate electricity for recharging the one or. ore batteries.

9. An electric or hydro electric drive system for powering a 10 vehicle which comprises an automatic switching system or enabling change over from charging of a first set of batteries and discharging of a second set of batteries to charging of the second set of batteries and discharging of the first set of batteries when the first set of batteries has lδ charged above a predetermined level or the second set of batteries has discharged below a predetermined level.

10. A vehicle incorporating the drive system according to any of the preceding claims.

20

-i -

11. A turbine generator characterised in that the impeller of the turbine is integral with the rotor of the generator.

12. A turbine generator as claimed in Claim 11, wherein the impeller/rotor is located within a chamber through which the motive fluid swirls, in use.

13. A drive system as claimed in any of Claims 1-9, wherein the, or each, turbine generator is a turbine generator as claimed in Claim 11 or Claim 12.