Field of the Invention

[0001] The present invention relates to a battery powered cycle and method for providing a charging current to a ¾attery powered cycle. The invention is suitable for, but not necessarily limited to, battery powered cycles with two in-line wheels.

Background of the Invention

[0002] Carbon based fuels are becoming more expensive and detrimental to the environment. As result, alternative fuels and propulsion technologies have been developed for cycles. One such technology is battery power in which a user charges a battery mounted to the cycle and the battery supplies electrical power to a motor (or motors) that propel the cycle. The charging of the battery may take a considerable time, and typically, the battery can be charged overnight or when the cycle is parked during office hours.

[0003] Battery powered cycles have a limited travel range that is typically dependent on battery charge, efficiency of the motor (or motors) driving the cycle and the efficiency of regenerative charging during breaking. When a battery powered cycle is decelerating it can be inefficient, and unnecessary, to reconfigure the motor (or motors) as regenerative breaks as such breaks may decelerate the cycle too rapidly. Furthermore, the rapid switching required to reconfigure the motor (or motors) into a generator (or generators) causes an unnecessary drain on the battery charge. This unnecessary drain may be significant in heavy traffic, or when travelling along undulating roads, when the cycle merely requires to decelerate slowly. It would therefore be useful to have an electric cycle that charges the battery during deceleration without necessarily requiring rapid switching to reconfigure the motor (or motors) as a regenerative break. Summary of the Invention

[0004] According to a first aspect of the present invention, there is provided a battery powered cycle including: a rider support; wheels rotatably mounted to the rider support; an electric motor with an output shaft coupled to one of the wheels; rechargeable batteries mounted to the rider support; a controller arranged to selectively supply electrical power from the rechargeable batteries to the motor; and a first electrical machine having an output continuously electrically coupled to the bank of batteries, the first electrical machine having an input drive shaft coupled to one of the wheels to thereby provide a charging current to the rechargeable batteries when the cycle is in forward motion.

[0005] Suitably, the output shaft of the electric motor is coupled to a first one of the wheels and the input shaft of the first electrical machine is coupled to a second one of the wheels.

[0006] Preferably, the first one of the wheels is a front wheel.

[0007] Suitably, there is a second electrical machine having an output continuously electrically coupled to the batteries, the second electrical machine having an input drive shaft coupled to one of the wheels to thereby provide a charging current to the rechargeable batteries when the cycle is in forward motion. [0008] Preferably, the first and second electrical machines are coupled to the same wheel.

^{^} [0009] Suitably, the first and second electricatmachines are coupled to the same wheel by a continuous flexible drive assembly.

[0010] Preferably, the continuous flexible drive assembly is a pulley and belt assembly that includes a drive pulley fixed to the same wheel, a support pulley rotatably mounted to the rider support and a continuous drive belt mounted on the drive pulley and the support pulley.

[0011] Preferably, the drive pulley has a diameter of almost the same size as a rim of the same wheel.

[0012] Suitably, the continuous flexible drive assembly is a sprocket and chain assembly that includes a drive sprocket fixed to the same wheel, a support sprocket rotatably mounted to the rider support and a continuous chain mounted on the drive sprocket and the support sprocket.

[0013] Preferably, the drive sprocket has a diameter of almost the same size as a rim of the same wheel.

[0014] Suitably, the pulley and belt assembly further includes pulleys on respective input drive shafts of the electrical machines that engage the continuous drive belt such that the support pulley is located between the pulleys on the input drive shafts.

[0015] Preferably, the electric motor is coupled to same wheel as the first and second electrical machines.

[0016] Suitably, the same wheel is a rear wheel.

[0017] Preferably, the first electrical machine is a generator. [0018] Suitably, the generator is coupled to the rechargeable batteries through a voltage regulator.

[00T9] Preferably, the first electrical machine is an alternator.

[0020] Suitably, the alternator is coupled to the rechargeable batteries through a rectifier circuit.

[0021] Preferably, in operation, when the controller detects actuation of a brake switch the controller reconfigures the motor to temporary function as a regenerative break to thereby provide a re-generative charging current to the rechargeable batteries.

[0022] Suitably, the said wheels are two in-line wheels.

[0023] According to a second aspect of the present invention, there is provided method for providing a charging current to a battery powered cycle, the method including: selectively supplying electrical power from rechargeable batteries to a motor to thereby propel the cycle; providing a continuous charging current to the rechargeable batteries when the cycle is in forward motion, the continuous charging current being generated from an electrical machine with a shaft coupled to a wheel of the cycle; detecting a breaking request signal; and reconfiguring the motor to function as a regenerative break to thereby provide a regenerative charging current to the rechargeable batteries in response to the detecting of the breaking request signal. [0024] Suitably, the method may be performed wherein the battery powered cycle is the cycle according to the first aspect of the present invention.

[0025] Further aspects of the present invention are as set out in the claims herein.

Brief Description of the Drawings

[0026] For a better understanding of the invention and to show how the same may be carried into effect, there will now be described by way of example only, specific embodiments, methods and processes according to the present invention with reference to the accompanying drawings in which:

Figure 1 illustrates a side schematic view of a battery powered cycle in accordance with a first preferred embodiment of the present invention;

Figure 2 illustrates a side schematic view of a battery powered cycle in accordance with a second preferred embodiment of the present invention;

Figure 3 illustrates a side schematic view of a battery powered cycle in accordance with a third preferred embodiment of the present invention;

Figure 4 illustrates a schematic circuit diagram of an electric circuit for a battery powered cycle in accordance with a fourth embodiment of the present invention; and

Figure 5 is a flow diagram illustrating a method for providing a charging current to a battery powered cycle in accordance with a fifth embodiment of the present invention.

Detailed Description of the Embodiments

[0027] There will now be described by way of example a specific mode contemplated by the inventor. In the following description numerous specific details are set forth in order to provide a thorough understanding. It will be apparent however, to one skilled in the art, that the present invention may be practiced without limitation to these specific details. In other instances, well known methods and structures have not been described in detail so as not to unnecessarily obscure the description.

[0028] Referring to Figure 1 there is illustrated a side schematic view of a battery powered cycle 100 in accordance with a first preferred embodiment of the present invention. The battery powered cycle 100 has a rider support 102 that includes a frame 104 formed from a cross bar 106, lower support section 108 and cross strut 110. Mounted on the cross bar 106 is a seat 112 and foot rests 114 are attached to a lower region of the lower support section 108. Extending at a rear of the frame 104 are rear forks 116 and pivotally mounted, about an upright axis, at a front region of the frame 104 are front forks 118. As will be apparent to a person skilled in the art, only one of the rear forks 116 and only one of the front forks 118 are in view in this illustration. The rear forks 116 and front forks 118 have respective shock absorbers 120, 122 typically formed by compression springs.

[0029] In this specification the rear forks 116 and front forks 118 are considered as part of the rider support 102. Other components of the battery powered cycle 100 include rear and front mudguards 124, 126, handlebars 128 mounted to the front forks 118, and there are also rear and front lights 130, 132. The battery powered cycle 100 has just two wheels these being two in-line wheels, in the form of a front wheel 134 and real wheel 136, rotatably mounted to the rider support 102. More specifically, the front wheel 134 is rotatably mounted to the front forks 118 and the rear wheel 136 is rotatably mounted to the rear forks 116. There is also an electric motor 138 with an output shaft (not illustrated) coupled the front wheel 134. The electric motor 138 is mounted (fixed) to the rider support 102, typically on the front forks 118, and thus in operation the electric motor 138 turns the front wheel 134, relative to the rider support 102, about a longitudinal axis of the motor's output shaft. [0030] The battery powered cycle 100 also has a bank of rechargeable batteries 140 (typically providing 48 Volts output) protected in a casing 142 that mounts the batteries 140 to the rider support 102. In this embodiment there is a controller 144 mounted to the cross bar 106, and on a housing of the controller 144 there is a human interface 146 for displaying cycle speed, remaining battery charge, distance travelled and similar useful information. Mounted to the rider support 102 is a first electrical machine 148 that has an output continuously electrically coupled to the bank of rechargeable batteries 140. The first electrical machine 148 has an input drive shaft 150 coupled to the rear wheel 136 to thereby provide a charging current to the bank of rechargeable batteries 140 when the cycle 100 is in forward motion. Also mounted to the rider support 102 is a second electrical machine 152 that has an output continuously electrically coupled to the bank of rechargeable batteries 140. The second electrical machine 152 has an input drive shaft 154 coupled to the rear wheel 136 to thereby also provide a charging current to the bank of rechargeable batteries 140 when the cycle 100 is in forward motion. The battery powered cycle 100 also has an electric throttle 168 and a break transducer in the form of a break switch 170 mounted to the handlebars 128. The electric throttle 168 in operation selectively supplies electric power, from the batteries 140, to the electric motor 138 and upon actuation of the break switch 170 the electric motor provides a regenerative charging current to the bank of rechargeable batteries 140.

[0031] In this embodiment, the electric motor 138 has a drive shaft coupled to the front wheel 134 and the drive shafts 150,154 of first electrical machine 148 and second electrical machine 152 are coupled to the same wheel (the rear wheel 136), by a continuous flexible drive assembly 156. The continuous flexible drive assembly 156 is a pulley and belt assembly that includes a drive pulley158 fixed on the rear wheel 138, a support pulley 160 rotatably mounted to the rider support 102 and a continuous drive belt 162 mounted on the drive pulley 158 and support pulley160. As shown, the drive pulley typically has a diameter of almost the same size (60cm) as a rim of the rear wheel 136. Furthermore, the assembly 156 also includes pulleys 164, 166 on respective drive shafts 150, 154 of the electrical machines 148, 152 and these pulleys164, 166 engage the continuous drive belt 162 such that the support pulley 160 is located between the pulleys 164, 166. As will be apparent to a person skilled in the art, the continuous drive belt 162 may have either a smooth or toothed surface (or surfaces) and the pulleys 158,160,164,166 may have a complementary surface to engage the toothed surface (or surfaces) of the belt.

[0032] In another embodiment, the pulley and belt assembly can be replaced with a sprocket and chain assembly in which the pulleys 158, 160, 164,166 are replaced with sprockets, and the drive belt 162 is replace by a continuous chain.

[0033] Referring to Figure 2 there is illustrated a side schematic view of a battery powered cycle 200 in accordance with a second preferred embodiment of the present invention. The battery powered cycle 200 is similar to the battery powered cycle 100, and to avoid repetition only the differences will be described. As illustrated, the electric motor 138 has an output shaft 202 coupled to the rear wheel 136 by a sprocket and chain assembly and therefore, in operation, the electric motor 138 turns (drives) the real wheel 136. More specifically, the electric motor 138 (shown in hidden detail) is mounted on the lower support section 108 and there is a drive sprocket 204 fixed to the output shaft 202. There is also a wheel sprocket 206 fixed to the rear wheel 136, and the wheel sprocket 206 and drive sprocket 204 (shown in hidden detail) are coupled by a continuous chain 208. Thus first electrical machine 148 and second electrical machine 152 are coupled to the same wheel (the rear wheel 136), by the continuous flexible drive assembly 156 and the electric motor 138 is also coupled to this same wheel (the rear wheel 136). Again, as above, the pulleys158, 160, 164,166 can be replaced with sprockets, and the drive belt 162 can be replaced by a continuous chain.

[0034] Referring to Figure 3 there is illustrated a side schematic view of a battery powered cycle 300 in accordance with a third preferred embodiment of the present invention. The battery powered cycle 300 is again similar to the battery powered cycle 100, and to avoid repetition only the differences will be described. The electric motor 138 has an output shaft 302 (both shown in hidden detail) coupled directly to the rear wheel 136. The electric motor 138 is mounted (fixed) to the rider support 102, typically on the rear forks 1 16, and thus in operation the electric motor 138 turns the rear wheel 136, relative to the rider support 102, about a longitudinal axis of 1he ^~ motor's output shaft. Again, as above, the pulley and belt assembly can be replaced with a sprocket and chain assembly in which the pulleys158, 160, 164,166 are replaced with sprockets, and the drive belt 162 is replace by a continuous chain.

[0035] Referring to Figure 4 there is illustrated a schematic circuit diagram of an electric circuit 400 for a battery powered cycle in accordance with a fourth embodiment of the present invention. The electric circuit 400 can be part of least any of the battery powered cycles 100, 200 or 300 and the electric circuit 400 includes the first electrical machine 148 in the form of a generator 402 and the second electrical machine 152 in the form of a generator 404. Both generators 402, 404 have outputs that are permanently (continuously) electrically coupled to the bank of rechargeable batteries 140 through respective regulators 406, 408 and diodes 410, 412. There is also an external charger 414 that can be coupled to a mains supply for charging the bank of jechargeable batteries 140 when the battery powered cycle is parked near a suitable mains supply.

[0036] The electric circuit 400 also has a controller 416 that includes a motor driver 418 with throttle control nodes coupled to the electric throttle 168 and break control nodes coupled to the break switch 170. The electric throttle 168 is potentiometer that varies a voltage at a throttle control node 450 and the break switch 170 is an on/off switch that provides a breaking request signal BRS when cycle breaking is required.

[0037] The motor driver 418 has a driver output 420 that is coupled to a terminal 424 of the electrical motor 138 through a diode 422. The terminal 424 is also coupled to a switch and regulator 426 forming part of the controller 416. The controller 416 also includes a relay 428 coupled to the human interface 146 and the human interface 146 is directly coupled to the bank of rechargeable batteries 140. The relay 428 controls supply of electric power from the bank of rechargeable batteries 140 to the motor driver 418 and switch and-regulator 426.

[0038] In operation, a driver inserts a key into the humannnterface 146 which actuates the relay 428 thereby connecting the bank of rechargeable batteries 140 to the motor driver 418 and switch and regulator 426. When the driver turns the throttle 168 the potentiometer varies a control voltage CV at the control node 450. This control voltage CV varies power at the driver output 420 which is supplied to the terminal 424 and thereby varies the speed of the motor 138. When the motor 138 is supplied with electrical power from the driver output 420 the wheels 134, 136 turn thereby propelling the cycle 100, 200 or 300 in a forward motion. Since the generators 404, 404 are continuously electrically coupled to the bank of rechargeable batteries 148, through their respective, regulators 406, 408 and diodes 410, 412, the generators 402, 404 provide a charging current to the rechargeable batteries when the cycle 100, 200 or 300 is in forward motion.

[0039] When Ihe cycle 100, 200 or 300 decelerates the generators 402, 404 still provide a charging current to the bank of rechargeable batteries 140. Also, when the break switch 170 is actuated to generate the breaking request signal BR, the controller 416 detects actuation of the brake switch 170 and reconfigures the motor 138 to temporary function as a re-generative break to thereby provide a re-generative charging current to the bank of rechargeable batteries 140. Furthermore, the generators 402, 404 continue to provide a charging current to the bank of rechargeable batteries 140 during regenerative breaking.

[0040] During regenerative breaking, the motor 138 is reconfigured as a generator by the cessation of electrical power at driver output 420 and connection of the terminal 424 through the switch and regulator 426 to the bank of rechargeable batteries 140. Also, the diode 422 blocks the current generated from the reconfigured motor 138 being supplied to the driver output 420. When the break switch 170 is released the motor 138 is reconfigured to function as a motor to propel the cycle 100, 200 or 300. In another embodiment, the first electrical machine 148 is an alternator that- replaces the generator 402 and the second electrical machine 152 is an alternator that replaces the generator 404. When such alternators are used, the regulatorsL406, 408 include rectifier circuits that couple a respective alternator to the rechargeable batteries 140. Furthermore, the motor 138 can be an AC motor which requires the diode 422 to be removed, and in regenerative breaking mode the AC motor becomes an alternator and thus the switch and regulator 426 would include a rectifier.

[0041] Referring to Figure 5 there is illustrated a flow diagram of a method 500 for providing a charging current to a battery powered cycle in accordance with a fifth embodiment of the present invention. The method 500 will be described with reference to the cycle 100 and electric circuit 400 however; the method 500 is not limited to this specific cycle 100 or circuit 400. The method 500 includes, at a selectively supplying block 510, a process of selectively supplying electrical power from the rechargeable batteries 142 to the motor 138 to thereby propel the cycle 100. The method 500 also includes, at a providing block 520, a process of providing a continuous charging current to the rechargeable batteries 142 when the cycle 100 is in forward motion, the continuous charging current being generated from the electrical machines148, 152 with their respective input drive shafts 150, 154 coupled to the rear wheel 136 of the cycle 100. At a detecting block 530, a detecting of the breaking request signal BRS from the break switch170 is performed, typically in the form of an interrupt signal. In response to the detecting of the breaking request signal BRS, at a reconfiguring block 540, the method 500 performs a process of reconfiguring the motor 138 to function as a regenerative break. The regenerative break provides a regenerative charging current to the rechargeable batteries 142 concurrently with the continuous charging current.

[0042] Advantageously, the present invention provides an electric cycle that charges the battery during deceleration without the need for rapid switching for reconfiguring the motor 138 for regenerative breaking. This is because the electrical machines148, 152 provide the continuous charging current to the rechargeable batteries 142 when the cycle 100 is decelerating. If required regenerative breakingt»y reconfiguring the motor is only provided when the break request signal is provided by actuation of the break switch.