WO2012057711A1

WO2012057711A1 - Range extender

Info

Publication number: WO2012057711A1
Application number: PCT/SG2011/000380
Authority: WO
Inventors: Rudi Hoebel
Original assignee: Clean Mobile Ag
Priority date: 2010-10-28
Filing date: 2011-10-28
Publication date: 2012-05-03

Abstract

This application provides a portable range extender. The portable range extender is used for supplying electrical en¬ ergy to a lightweight electric vehicle. The portable range extender comprises a dynamoelectric machine, an internal com¬ bustion engine, a port, and a controller. The dynamoelectric machine is provided for electrically coupling to an external energy storage device. The internal combustion engine is pro¬ vided for converting combustible fuel to electrical energy. The internal combustion engine is coupled to the dynamoelec¬ tric machine by a shaft. The port is provided for transmit- ting electric energy generated by the dynamoelectric machine. The controller for receiving at least one input. In response to the input, the range extender provides a first mode, a se¬ cond mode, and a third mode.

Description

RANGE EXTENDER

This application relates to a range extender. A range extender in a serial hybrid electric vehicle includes a small internal combustion engine that drives an alternator to produce electrical energy.

This electrical energy is used for charging a battery or a battery system of the vehicle that in turn actuates an electric motor of a drive system or power train of the serial hybrid electric vehicle.

The range extender is therefore used to extend an operating range of electric vehicles with a battery that may have been charged with other means . Because current battery technology may not provide a pure electric vehicle with sufficient electrical energy for a desired range, the hybrid electric vehicle having the range extender offers a compromise between an in- ternal combustion powered vehicle and a pure electric vehicle. This compromise improves vehicle performance and extends an operating range of the vehicle while keeping emissions minimal . It is an object of this application to provide an improved range extender.

The application provides a portable range extender. The range extender is used for supplying electrical energy to a light- weight electric vehicle, such as a bicycle, for driving wheels of the electric vehicle. The portable range extender includes a dynamoelectric machine, an internal combustion engine, a port, and a controller.

The dynamoelectric machine is used for coupling electrically to an external energy storage device. The energy storage device can supply electrical energy to the dynamoelectric machine to activate the dynamoelectric machine for operating a motor. The energy storage device is often provided as a rechargeable battery unit that includes one or more batteries.

The internal combustion engine is used for converting combustible fuel, which can be in a liquid or a gaseous form, to electrical energy. The internal combustion engine is structurally coupled to the dynamoelectric machine by a shaft.

The shaft allows the energized dynamoelectric machine to drive the internal combustion engine in order to start the internal combustion engine. The shaft also allows the operational internal combustion engine to drive the dynamoelectric machine such that the dynamoelectric machine generates electrical energy instead of consuming the electrical energy.

The port is used for selectively transmitting electric energy generated by the dynamoelectric machine to a motor of the ve- hicle, wherein the motor is used for driving one or more wheels of the vehicle.

The controller is used for receiving at least one input. The input can originate from a user, from the external storage de- vice, or from a control unit. In one example, the controller receives information indicating that the storage device has low electrical charge. In another example, the controller re- ceives information indicating that the storage device is fully charged.

In response to the input, the controller then manages the range extender such that the range extender provides a first mode, a second mode, and a third mode.

In the first mode, the dynamoelectric machine operates a motor, wherein it receives electrical energy from the external energy storage device to rotate the shaft. In the second mode, the internal combustion engine operates a prime mover, wherein it converts the combustible fuel to electrical energy for rotating or driving the shaft. In the third mode, the dynamoelectric machine operates as a generator, wherein it generates electrical energy. This electrical energy is intended for transmitting via the port to external motor for driving the motor .

The combustible fuel can comprise Liquefied Petroleum Gas (LPG) fuel although other types of fuel are also possible. The portable range extender can include a first valve, which is actuated by the controller, for controlling release of LPG to the internal combustion engine. A second valve, which is also actuated by the controller, can also be provided for control- ling release of air for mixing with the LPG to provide a mixture of LPG and air.

The portable range extender can include a microphone for detecting an operational status of the internal combustion en- gine . The microphone is electrical connected to the controller and it is used for picking up sounds of the internal combustion engine, the dynamoelectric machine, or both. In one exam- pie, when no sound is picked up the microphone, it is an indication that both the internal combustion engine and the dyna- moelectric machine are not working. When excessive loud noise is picked up by the microphone, this is used to indicate that the internal combustion engine or the dynamoelectric machine is not working properly.

According to another aspect of the application, the portable range extender has one or more temperature sensors. These tem- perature sensors are also electrical connected to the controller .

The temperature sensor can be provided at a fuel inlet of the internal combustion engine for monitoring the fuel supplied to the internal combustion engine. Alternatively, the temperature sensor can be provided at an exhaust outlet of the internal combustion engine to monitor exhaust of the internal combustion engine. The temperature sensor can also be provided at a cylinder head of the internal combustion engine to measure op- erational temperature of the internal combustion engine.

The portable range extender can include an oxygen sensor that is provided at an exhaust outlet of the internal combustion engine to measure fuel combustion status of the combustion en- gine . The portable range extender can also include a shaft speed sensor to measure rotating speed of the shaft connecting the internal combustion engine to the dynamoelectric machine.

In accordance to another aspect of the application, the porta- ble range extender includes one or more strain gauges for detecting an operation of the internal combustion engine or the dynamoelectric machine depending on where the strain gauges are located.

For developing or for testing of the range extender, the port- able range extender can comprise a resistor. The resistor serves to consume electrical energy generated by the dynamoelectric machine. In essence, the consuming converts the electrical energy into heat energy. This allows the range extender to be developed without connecting to a vehicle.

In many implementations, the portable range extender provides the first mode, the second mode, and the third mode upon receiving a first pre-determined energy data of an energy storage device. The energy data indicates that the external energy storage device is not fully charged. The first, the second, and the third modes are then initiated in sequence to provide electrical energy to the energy storage device.

The second mode is often provided after the first mode and the third mode is often provided after the second mode unless the sensor detects an anomaly.

The portable range extender can provide a standby mode. The portable range extender enters the standby mode upon receiving a second pre-determined energy data of the energy storage device. The second pre-determined energy data indicates that the electrical storage device is fully charged.

In the standby mode, the supply of combustible fuel is cut. This then causes the internal combustion engine to cease operating. In other words, the internal combustion engine stops driving the dynamoelectric machine. In this mode, the dynamoe- lectric machine also stops receiving electrical energy from the external storage device.

The portable range extender can provide an abnormal mode . The portable range extender enters the abnormal mode upon receiving an abnormal sensor data from at least one of a microphone, a shaft speed sensor, an oxygen sensor, and a temperature sensor. The abnormal sensor data indicates that the range extender needs repair. The range extender does not work until the range extender stops generating the abnormal sensor data.

Furthermore, the application provides a portable range extender which comprises a secondary generator with a thermoelectric generator, wherein a heating portion of the thermoelectric generator is in thermal contact with an exhaust pipe of the portable range extender.

Furthermore, the application provides a portable range extender which comprises a secondary generator with a heat differ- ence driven engine, wherein a heating portion of the heat difference driven engine is in thermal contact with an exhaust pipe of the portable range extender.

An electric line of the secondary generator is connectable to a battery to be charged via a switch. The electric line may furthermore be connected to a transformer for increasing an output voltage of the secondary generator. By using the secondary generator, part of the heat energy from a combustion driven generator can be recovered to charge the battery.

The application provides a lightweight electric vehicle, such as a bicycle. The lightweight electric vehicle comprises the above-mentioned portable range extender, an energy storage device, and a motor. The energy storage device is used for providing electrical energy to the portable range extender to start or to initiate the portable range extender. The energy storage device is also used for receiving electrical energy from the portable range extender when the portable range extender is operating. The motor is used for receiving electrical energy from the energy storage device to drive at least one wheel of the lightweight vehicle.

Fig. 1 illustrates an embodiment of an electric bicycle, Fig. 2 illustrates a side view of a range extender of the bicycle of Fig. 1,

Fig. 3 illustrates a top view of the range extender of Fig.

2,

Fig. 4 illustrates a set of expected characteristics of the range extender of Fig. 1,

Fig. 5 illustrates a further set of expected characteristics of the range extender of Fig. 1,

Fig. 6 illustrates a state diagram of the range extender of

Fig. 2, and

Fig. 7 illustrates the electric bicycle of Fig. 1 that is equipped with a Stirling engine,

Fig. 8 illustrates the electric bicycle of Fig. 1 that is equipped with a Seebeck effect device,

Fig. 9 illustrates a portion of the electric bycicle with a secondary electric generator and

Fig. 10 illustrates a circuit diagram of an electric drive system of the electric bicycle of Fig. 1.

In the following description, details are provided to describe the embodiments of the specification. It shall be apparent to one skilled in the art, however, that the embodiments may be practised without such details.

The Figs, below have similar parts. The similar parts have the same names or similar part numbers. The description of the similar parts is hereby incorporated by reference, where appropriate, thereby reducing repetition of text without limiting the disclosure. Fig. 1 shows an electric bicycle 10. The bicycle 10 includes a frame 12, a motor assembly 13, and a transmission assembly 14. Both the motor assembly 13 and the transmission assembly 14 are attached to the frame 12. The frame 12 includes a substantially horizontal top tube 16. A front end of the top tube 16 is fixed to a head tube 17 whilst a rear end of the top tube 16 is fixed to a substantially vertical seat tube 19. The head tube 17 is also fixed to an upper end of a down tube 20. A bottom end of the seat tube 19 is fixed to a lower end of the down tube 20.

The upper end of the seat tube 19 is also fixed to an upper end of an inclined seat stay tube 23 whilst the lower end of the seat tube 19 is also fixed to one end of a substantially horizontal chain stay tube 25. A lower end of the seat stay tube 23 and the other end of the chain stay tube 25 are connected by a joint.

A front wheel 28 is coupled to a fork 29 that is inserted into the head tube 17. The front wheel 28 includes a front brake, which is not shown in Fig. 1. Likewise, a rear wheel 31 is coupled to the joint between the chain stay tube 25 and the seat stay tube 23. The rear wheel 31 includes a rear brake, which is not shown in Fig. 1. A handle bar assembly 33 is coupled to an upper end of the head tube 17. Actuators for the front and rear brakes are mounted on the handler bar assembly 33. A seat 35 is coupled to the upper end of the seat tube 19.

The motor assembly 13 includes a range extender 37 that is electrically connected to a controller 39 and to a driving battery assembly 42. The driving battery assembly 42 is elec- trically connected a driving motor 45.

The driving battery assembly 42 includes a rechargeable driving battery and a battery management device that is electrically connected to the driving battery. The battery management device is also electrically connected to the controller 39.

The range extender 37 is attached to the driving battery assembly 42, which is attached to the down tube 20. The controller 39 is attached to the seat tube 19. The driving motor 45 is attached to the transmission assembly 14.

The transmission assembly 14 includes a front sprocket assem-^' bly 47 and a rear sprocket assembly 48. The front sprocket assembly 47 is coupled to the rear sprocket assembly 48 by a chain 50. The front sprocket assembly 47 is attached to the driving motor 45. The driving motor 45 is provided here as a permanent magnet DC brushless motor although other types of motor are also possible. The front sprocket assembly 47 includes one or more front gears and a front derailleur, both of which are not shown in Fig. 1. One of the front gears is coupled to the chain 50. A pair of crank arms with a pair of pedals is coupled to the front sprocket assembly 47. The crank arms and the pedals are not shown for simplicity of the Fig. 1. Similarly, the rear sprocket assembly 48 includes one or more rear gears and a rear derailleur, both of which are not shown in Fig. 1. One of the rear gears is coupled to the chain 50. Actuators for actuating the front derailleur and the rear derailleur are mounted on the handlebar assembly 33. The derailleur actuators are not shown in Fig. 1.

The range extender 37 is electrically connected to the controller 39 via a Controller Area Network (CAN) bus 55, as illustrated in Fig. 2. The controller 39 has a power-on button 57 and a power-off button 58 as well as a display unit 59 and a microphone -61.

The range extender 37 includes an internal combustion engine 63 and a dynamoelectric machine 65 that is connected to the internal combustion engine 63 by a common shaft 67. The inter- nal combustion engine 63 and the dynamoelectric machine 65 are bolted to an inside of a concrete panel casing 69.

The dynamoelectric machine 65 is selectively connected to the driving battery assembly 42 via a variable resistor 71. The variable resistor 71 is electrically connected to the controller 39.

The combustion engine 63 is provided here as a compression ignition engine. The combustion engine 63 has a cylinder head 73 with a glow plug 74, a combustion mixture inlet 76, as well as an engine gas exhaust pipe 77. A cylinder temperature sensor 79 is placed on the cylinder head 73 whilst another engine temperature sensor 81 is placed inside the combustion engine 63. The cylinder temperature sensor 79 and the engine temperature sensor 81 are connected to the controller 39. One end of the gas exhaust pipe 77 is connected to the combustion engine 63 whilst another end of the gas exhaust pipe 77 is connected an exhaust window 83 of the casing 69 by a heat tolerant tube 85. An exhaust temperature sensor 86 is placed on the gas exhaust pipe 77 and a lambda or oxygen sensor 88 is placed inside the exhaust pipe 77. The exhaust temperature sensor 86 and the lambda oxygen sensor 88 are connected to the controller 39.

A piping assembly 90 connects a Liquefied Petroleum Gas (LPG) container 92 to the combustion mixture inlet 76. The piping assembly 90 includes a pipe 94, a valve 96 with an actuator 97 for controlling inlet of LP gas, and a valve 100 with an actuator 102 for controlling inlet of air. A combustion-mixture temperature sensor 104 is mounted inside the piping assembly 90. The combustion-mixture temperature sensor 104 is connected to the controller 39.

The concrete panel casing 69 has an inlet air window 106 and an outlet air window 108, as illustrated in Fig. 3. An inlet air fan 110 is mounted at the inlet air window 106 whilst an outlet air fan 112 is mounted at the outlet air window 108. A plurality of strain gauges 120 is placed inside the concrete panel casing 69. The strain gauges 120 are also connected to the controller 39. Referring to Fig. 2, a motor shaft rotation sensor 114 is also mounted inside the concrete panel casing 69. The motor shaft rotation sensor 114 is also connected to the controller 39. In a generic sense, the internal combustion engine 63 can be provided as compression ignition or as a spark ignition engine . It can also be provided as a two-stroke engine, a four- stroke engine, or as a gas turbine engine.

In use, the bicycle 10 serves as mountain bicycle that is designed for off-road cycling, although the bicycle 10 can also serve as other types of bicycle.

The bicycle 10 may be placed in a manual mode where a rider turns the wheels 28 and 31 only by rotating the pedals. The driving force from the pedals is transmitted, via the crank arms, via one of the front gears, via the chain 50, and via one of the rear gears, to the rear wheel 31.

Alternatively, the bicycle 10 may be placed in an automatic mode. In particular, the automatic mode has a starting phase and an operating phase .

In the starting phase, the driving battery assembly 42 serves as a starter battery for starting the range extender 37. The ^' driving battery assembly 42 includes a socket for receiving power or charge from an external charger. The external charger itself can be powered by electricity from a home. The driving battery assembly 42 is used for providing electrical power to the range extender 37. The power-on button 57 is used connecting electrical power from the driving battery assembly 42 to the controller 39. The CAN bus 55 is used by the controller 39 to communicate and to control various parts of the range extender 37. The glow plug 74 is used for receiving electrical power from the driving battery assembly 42 and for converting the received electrical power to heat energy for elevating a temperature of the combustion engine 63. The actuators 97 and 102 are used by the controller 39 to release a combustion mixture of LP gas and of air to the combustion engine 63 via the pipe 94. The dynamoelectric machine 65 is used for receiving electrical power from the driving battery assembly 42 and for converting the received electrical power to mechanical power for turning the common shaft 67, which in turn actuates cylinders of the combustion engine 63.

In an operational phase, the combustion engine 63 converts the combustion mixture of LP gas and of air to mechanical energy to drive the common shaft 67. The common shaft 67, in turn, is used transferring torque from the combustion engine 63 to the dynamoelectric machine 65. The dynamoelectric machine 65 is used to generate electrical power that is used for consuming by the driving battery assembly 42. The driving battery assembly 42 is used for powering or for driving the driving motor 45 to turn the rear wheel 31. The driving motor 45 is intended for turning and for driving the front sprocket assembly 47, although, in certain implementations, it can also be used to drive the rear sprocket assembly 48. The range extender 37 can charge the driving battery assembly 42 during this operational phase .

The gas exhaust pipe 77 is used for channelling exhaust gas from the combustion engine 63 to outside of the concrete panel casing 69 via the exhaust window 83. The inlet air fan 110 is used for channelling air from outside of the concrete panel casing 69 to inside of the concrete panel casing 69 via the inlet air window 106. In contrast, the outlet air fan 112 is used for channelling heated air from the inside of the con- crete panel casing 69 to the outside of the concrete panel casing 69 via the outlet air window 108. In other words, the inlet air fan 110 and the outlet air fan 112 serve to cool the combustion engine 63.

Readings from the combustion-mixture temperature sensor 104, the lambda sensor 88, and the exhaust temperature sensor 86 are used to adjust the composition of the combustion mixture by the controller 39. Readings of the motor shaft rotation sensor 114 are used to monitor a rotating speed of the common shaft 67 by the controller 39. Readings of the cylinder temperature sensor 79 are used to adjust the glow plug 74 for heating the combustion engine 63 by the controller 39. Readings of the engine temperature sensor 81 and the microphone 61 are used to monitor and to adjust the operation of the combustion engine 63 by the controller 39. The microphone 61 is used for detecting operation of the range extender 37. It can also be used to detect any anomaly in the operation of the internal combustion engine 63. Readings of the strain gauges 120 are used to monitor a vibration and torque of the combustion engine 63 by the controller 39.

The bicycle 10 may also be configured in a mix mode, where the motor assembly 14 may operate the bicycle 10 and the rider may choose to operate manually the bicycle 10 simply by turning the pedals faster than the motor assembly 10 is able to rotate the front sprocket assembly 47.

In addition, the rider manually actuates the front derailleur actuator to select one of the front gears. Likewise, the rider can also manually actuate the rear derailleur actuator to select one of the rear gears. In a generic sense, the front and rear derailleur actuators can also functional automatically, rather than manually, using the rotating speed of the one of the wheels 28 and 31. The power-off button 58 is used to switch off the controller 39 in an emergency. The display unit 59 is used to provide visual status of the controller 39. The concrete panel casing 69 provides sound insulation for the range extender 37 such that noises produced by the range extender 37 are most kept within the concrete panel casing 69.

In one implementation, the dynamoelectric machine 65 turns at between about 2,000 RPM (rounds per minute) and about 16,000 RP . It can turn at about 15,000 RPM to produce about 0.6 hp (horsepower) or 448 watts.

The range extender 37 can be adapted to provide different electrical power ranges. Fig. 4 shows a set of expected characteristics of the range extender of Fig. 1. In this implementation, the range extender 37 is adapted to provide about 250 watts of electrical power.^" The power is provided when the output voltage ranges from about 40 volts to about 55 volts and the output electrical current ranges from about 4 amperes to about 6 amperes.

Fig. 5 shows a further set of expected characteristics of the range extender of Fig. 1. In this implementation, the range extender 37 is adapted to provide about 700 watts of electri- cal power. The power is provided when the output voltage ranges from about 40 volts to about 55 volts and the output elec- trical current ranges from about 9 amperes to about 15 amperes.

Fig. 6 shows a state diagram 150 of the range extender 37 of Fig. 2. The range extender state diagram 150 has an offline state 152, a standby state 154, a charge generation state 156, and an abnormal state 158. The offline state 152 is linked to the standby state 154 whilst the standby state 154 is linked to the charge generation state 156. The abnormal state 158 is linked to the standby state 154.

In the offline state, the range extender 37 is switched off. The dynamoelectric machine 165 and the combustion engine 163 are not functioning.

The range extender 37 transits from the offline state 152 to the standby state 154 when the range extender 37 is switched on. Power from the driving battery assembly 42 is connected to the range extender 37. Conversely, from the standby state 154, the range extender 37 transits to the offline state 152 when the range extender 37 is switched off.

The range extender 37 transits from the standby state 154 to the charge generation state 156 when the controller 39 detects or is notified that the driving battery unit 42 is not fully charged. In other words, when the controller 39 detects that the charge status of the driving battery unit 42 is below a certain operational level, the controller 39 transits the range extender 37 to the standby state 154.

The controller 39 receives status information of the driving battery unit 42 from the driving battery management device and it monitors the battery charge status of the driving battery unit 42.

Conversely, from the charge generation state 156, the range extender 37 transits to the standby state 154 when the controller 39 detects or is notified that the driving battery unit 42 is fully charged. Put differently, the range extender 37 transits from the charge generation state 156 to the standby state 154 when the charge status of the driving bat- tery unit 42 exceeds a certain battery capacity level.

In the charge generation state 156, the range extender 37 provides electrical charge to the driving battery unit 42. To provide the electrical charge, the controller 39 connects the glow plug 174 to driving battery assembly 42 such that the glow plug 174 receives electrical energy to heat the combustion engine 163. The controller 39 also actuates the actuators 197 and 202 to release combustion mixture of LP gas and of air to the combustion chambers via the pipe 194.

After this, the controller 39 connects the dynamoelectric ma-^" chine 165 to the driving battery assembly 42 for receiving electrical power to turn the common shaft 167, which also ac- tuates cylinders of the heated combustion engine 163. The actuated cylinders then compress the combustion mixture that fills the combustion chambers. The compression then causes the compressed combustion mixture to ignite and to explode at a predetermined pressure and temperature. This explosion drives and turns a shaft of the combustion engine 163. The driven combustion engine shaft, in turn, drives the common shaft 167, which transfers a torque to a shaft of the dynamoelectric ma- chine 165. The controller 39 uses readings of the motor shaft rotation sensor 214 to determine and to verify that the common shaft 167 is turning. The driven dynamoelectric machine 165 later generates electrical energy, rather than consuming elec- trical energy from driving battery assembly 42. This generated electrical energy is then transferred to the driving battery unit 42 for charging the driving battery unit 42.

The gas exhaust pipe 177 afterward channels the ignited com- bustion mixture or exhaust gas from the combustion chambers of the combustion engine 163 to outside of the concrete panel casing 169 via the exhaust window 183. The inlet air fan 210 also channels air from outside of the concrete panel casing 169 to inside of the concrete panel casing 169 via the inlet air window 206. The outside air is used for cooling the combustion engine 163. Likewise, the outlet air fan 212 channels the heated air from the inside of the concrete panel casing 169 to the outside of the concrete panel casing 169 via the outlet air window 208.

When the controller 39 detects that the driving battery unit 42 is fully charged, the controller 39 stops the production of charging electrical current. To achieve the stoppage, the controller 39 adjusting the actuators 196 and 202 such that the combustion engine 163 does not receive the combustion mixture.

For development, the charge generation state 156 includes a test mode. In this test mode, the output of the dynamoelectric machine 165 is connected to the variable resistor 171, instead of the electric motor 45. The variable resistor 171 here serves as a load to consume the electrical power from the dy- namoelectric machine 165. This arrangement is suitable for laboratory testing of the range extender 37.

The controller 39 also receives readings from its sensors and it stores these received readings along with time records of the readings. These readings can be used for improving of the range extender 37.

In one mode, the controller 39 records raw data values of the received readings over a predetermined period, such as an hour, together with corresponding commands of the controller 39.

In another mode, the controller 39 treats values of the re- ceived readings in order to use less data storage space. In one example, the treated values comprise average, minimum, and maximum values of the received readings over every time period, which can be 10 minutes. The treated values are then recorded together with corresponding commands of the controller 39. These recorded values are later transmitted to an external computing device via a port, such as Universal Serial Bus (USB) port, for studying and for improving the range extender^" 37. The range extender 37 transits from the charge generation state 156 to the abnormal state 158 when the controller 39 detects abnormal sensor readings. Readings from the microphone 161 are used to detect abnormal engine noises whilst readings from the strain gauges 220 are used to detect abnormal engine vibration by the controller 39. Furthermore, readings from the motor shaft rotation sensor 214 are also used to detect abnor- mal rotating speed of the common shaft 167 by the controller 39.

In the range extender abnormal state, the controller 39 switches off the range extender 37. From the abnormal state 158, the range extender 37 then transits to the standby state 154 when, for example, a user rectifies these abnormal sensor readings .

One embodiment of operating the range extender unit is provided below.

The range extender unit should be connected to the battery and after every reset. The unit would then start the automatically in an operation mode.

The range extender unit monitors battery voltage and starts charging as soon as the battery voltage drops below a defined threshold. It would stop charging as soon as the battery voltage exceeds a pre-defined switch off threshold. The thresholds for automatic charging can be modified with a computer. The second line of a display of the range extender would indicate^" "charging mode" as long as the unit is providing voltage to the electrical system.

The range extender unit would go through a cold start phase of about 20 minutes before reaching its full rated output.

If the battery is sufficiently charged and the range extender unit is not providing power to the battery, the range extender unit would remain in the standby mode. Should the range extender detect a malfunction such as an empty fuel cartridge, it would shut down and advise the user on how to correct the situation with a message "Please change fuel cartridge". Automatic operation can be resumed by using the reset button after this error has been corrected.

The range extender unit features an intelligent antifreeze feature. If the temperature drops close to the freezing point then a fuel cell of the range extender unit starts automati- cally a charging mode to prevent freezing. As soon as the unit has warmed up enough, it stops the antifreeze mode. The antifreeze mode works also if the unit is switched off. If the unit is in antifreeze mode, the message "Antifreeze mode" will appear on the second line. The first line will indicate the current operating mode, for example "Off".

The antifreeze function works only as long as a fuel cartridge and a sufficiently intact battery are connected. Possible ways of maintaining and storing as well as operating in winter of the range extender are provided below.

If, despite precautions, the unit does freeze, it should be thawed in a warm place for approximately 24 hours before oper- ating. The unit's performance may diminish if it froze repeatedly .

Running in the antifreeze mode, the unit would consume approximately 10 litres of methanol in a course of a five-month Central European winter. Fuel cartridge connector should be checked when an error message is displayed. Fuel cartridge connection should be checked and the cartridge should be screwed tightly. Check Cartridge hose should be checked for kinks. Hose and connection should be checked for dirt.

Service fluid should be refilled when an error message is displayed. Service fluid should be added. Then, check that exhaust can escape and that ambient temperature is below 45° C.

Battery voltage should be checked when an error message is displayed. The error message may indicate that battery voltage is too low due to a sense line, that the battery voltage is too high due to the sense line, that battery voltage is too low due to a power line, or that battery voltage is too high due to the power line.

Connections should also be checked. The battery should be checked whether it is the proper type. Battery voltage should also be checked. If it is too low, then use an external battery charger to recharge the battery. Other charging devices such as generators or regulators should be checked for defects . The user should wait when unit is restarting automatically.

In summary, the embodiment provides a portable range extender. The range extender is capable of supplying electrical energy to a vehicle, such as a bicycle. The portable range extender comprises an internal combustion engine, a dynamoelectric machine, a controller, and one or more sensors. The internal combustion engine is adapted for converting Liquefied Petroleum Gas (LPG) to electrical energy. The dynamoelectric machine structurally is coupled to the internal combustion engine by a shaft and is adapted for electrically cou- pling to an energy storage device. The controller is used for receiving at least one user input.

In response to the user input to the controller, ' the range extender uses at least one reading of the sensor to provide a first mode, a second mode and a third mode.

In the first mode, electrical energy is transferred from the energy storage device to a motor of the dynamoelectric machine for driving the shaft to rotate in which the range extender enters the second mode. In the second mode, the internal combustion engine is activated as a prime mover in which the range extender enters the third mode. In the third mode, the dynamoelectric machine is activated in a generation mode to generate electrical energy.

In general, the sensor can comprise a motor shaft rotation sensor, a cylinder temperature sensor, an exhaust temperature^" sensor, a strain gauge, a combustion-mixture temperature sensor, or an oxygen sensor.

Fig. 7 shows the electric bicycle 10 of Fig. 1 that is equipped with a secondary energy generation device 72, which is also known as secondary electrical generator 72, that comprises a combination of a heat difference driven engine 160, such as a Sterling engine, a Rankine engine or a Brayton engine, which drives an electrical generator. Heat driven engines and especially Stirling engines are heat engines that operate by cyclic compression and expansion of air or other gas, which is also called the working fluid. Operation is performed at different temperature levels such that there is a net conversion of heat energy to mechanical work.

In one specific embodiment, the heat difference driven engine 160 is provided as a Stirling engine 160. However, the explanations below apply in similar manner to other heat difference driven engines as well.

The Stirling engine 160 includes a working fluid, such as air or water. The Stirling engine 160 is attached to the range extender 37. In particular, the Stirling engine 160 is attached to the common shaft 67 of the dynamoelectric machine 65 of the range extender 67 by a mechanical linkage.

In use, the Stirling engine 160 acts an external combustion engine, which receives heat energy from the operating range extender 37 and converts this heat energy to a mechanical en- ergy.

r

Specifically, the working fluid of the Stirling engine 160 receives heat from the operating internal combustion engine 63 of the range extender 37. The heated working fluid then acts to turn the common shaft 67 of the range extender 67 by a mechanical linkage. The turning common shaft 67 then turns the dynamoelectric machine 65 for generating electrical power that is consumed by the driving battery assembly 42. This Stirling engine 160 improves efficient of the range extender 160 by converting heat energy of the range extender 160 to electrical energy for the driving battery assembly 42. Without the waste energy recovery of the Stirling engine 160, this heat energy would be wasted.

The general cycle of the Sterling engine consists of compress- ing cool gas, heating the gas at the exhaust of the combustion engine of the range extender, expanding the hot gas, and finally cooling the gas at the external heat dissipator of the range extender before repeating the cycle. The efficiency of the process is narrowly restricted by the efficiency of the Carnot cycle, which depends on the temperature difference between the exhaust and the external heat dissipator.

In the present embodiment, the heat source is provided by the combustion of fuel in the internal combustion engine of the range extender. The external heat dissipator of the range extender can be cooled and maintained at a low temperature by such means as cold water from an external supply.

Fig. 8 shows the electric bicycle of Fig. 1 wherein the sec- ondary generator 72 comprises a Seebeck effect device 164. The Seebeck effect device 164 is attached to the range extender 37 and to driving battery assembly 42. The Seebeck effect device^" 164 includes a thermocouple unit. In operation, the thermocouple unit of the Seebeck effect device 164 receives heat from the operating range extender 37 and it converts this heat to electrical energy, which is then transferred to the driving battery assembly 42. Without the Seebeck effect device 164, this heat would not be used. However, with the Seebeck effect device 164, this heat is put into use as it is converted to electrical energy that is consumed by the driving battery assembly 42.

In other words, the secondary generator 72 is provided by a thermoelectric generator 164 that comprises one or more thermo-elements. The thermoelectric generator 164, which is also referred to as Seebeck effect device 164, makes use of the Seebeck effect. According to the application, the thermoelements may comprise bimetallic junctions or, preferably, semiconducting junctions such as bismuth telluride p-n junctions or others. Other thermoelectric materials such as nanostructured bulk nanowires and thin film materials may be used as well. Advantageously, many thermo-elements may be connected in series to generate a larger output voltage. In addi- tion, several rows of thermo-elements, which are connected in series, may be connected in parallel to obtain a larger output current.

If the thermo-elements are provided as p-n junctions that cora- prise a p-doped and an n-doped material, a cooling portion of the p-doped material is in thermal contact with to the cooling portion of the secondary generator 72 and a heating portion of the p-doped material is in thermal contact with the heating portion of the secondary generator 72. A heating portion of the n-doped material, which is in electrical contact with the heating portion of the p-doped material, is in thermal contact with the heating portion of the secondary generator 72 and a cooling portion of the n-doped material is in thermal contact with the cooling portion of the secondary generator 72.

The thermoelectric generator 164 can be made compact and inexpensive. Furthermore, it can directly provide a DC current for charging the battery without the need of an alternator. The thermoelectric generator does not comprise moving parts such as a heat engine and is therefore easy to maintain. Fig. 9 shows a schematic view of a section of a range extender with the secondary electrical generator 72. The secondary generator 72 comprises a heating portion which is attached to an engine gas exhaust pipe 77' that is connected to an exhaust window 83' . In a further modification of this embodiment, the heating portion of the secondary generator 72 is connected to a cooling agent of the dynamoelectric machine 65. A cooling portion of the secondary generator 72 is attached to a portion of a casing. Cooling fins 75 are provided on the cooling side for contact with the ambient air. A power line of the second- ary generator 72 connects the secondary generator with a battery that is to be charged. A transformer 78 is provided between a first and a second portion of the power line. The transformer 78 is configured to increase the output voltage of the secondary electric generator 72.

Different embodiments of the driving battery assembly 42 are possible.

Fig. 10 depicts one embodiment of the driving battery assembly 42. Fig. 10 shows a circuit diagram of an electric drive system 203 of the electric bicycle 10 of Fig. 1.

The electric drive system 203 comprises a fuel conversion unit as well as the driving battery assembly 42, the motor 45, and the controller 39 of the electric bicycle 10. The driving battery assembly 42 is connected to the fuel conversion unit via a first changeover switch UM1 and a second changeover switch UM2 and to the motor 45 via switches U l while the changeover switches UMl and UM2 are connected to the controller 39.

In particular, the controller 39 includes a microprocessor 213. The microprocessor 213 is also called a microcontroller.

The driving battery assembly 42 includes a first group of energy storage and a second group of energy storage. Referring to the first group of energy storage, it has a first stack 205 of a plurality of rechargeable storage batteries Cll to Cnl with a first transformer 321. The variable "n" can have different integer values. The storage batteries Cll to Cnl are connected electrically in a series. A positive voltage terminal of the first battery Cll is connected to a negative voltage terminal of the second battery C21. A positive voltage terminal of the second battery C21 is connected to a negative voltage terminal of the third battery C31. In a similar manner, the other batteries C41 to Cnl are connected.

In addition, a negative voltage terminal of the first battery Cll is connected to an electrical ground 236 while a positive voltage terminal of the battery Cnl is connected to a stack terminal of the changeover switch UMl.

The transformer 321 has a magnetic core 311 with a primary coil Npl and with a plurality of secondary coils Nil to Nnl.

The primary coil Npl has 90 windings that are wound around the magnetic core 311. A first end All of the primary coil Npl is connected to the stack terminal of the changeover switch UM1 while a second end A21 of the primary coil Npl is connected to the electrical ground 236 via a primary switch Spll. In particular, the second end A21 of the primary coil Npl is con- nected to a transformer terminal of a primary switch Spll. A ground terminal of the primary switch Spll is connected to the electrical ground 236. The primary switch Spll also has a switching control input, which is connected to the microcontroller 213.

Each of the secondary coils Nil to Nnl has three windings that are wound around the magnetic core 311 and is connected in parallel to each of the corresponding storage batteries Cll to Cnl via one of a plurality of secondary switches Sll to Snl .

A positive voltage terminal of the secondary coil Nil is connected to the positive voltage terminal of the storage battery Cll. In contrast, a negative voltage terminal of the secondary coil Nil is connected to a first terminal of the secondary switch Sll while a second terminal of the secondary switch Sll is connected to the negative voltage terminal of the storage battery Cll. The secondary switch Sll also includes a switch-- ing control input, which is connected to the microcontroller 213. In a similar manner, the secondary coils N21 to Nnl are connected to the corresponding storage batteries C21 to Cnl via the corresponding secondary switches S21 to Snl.

Referring to the second group of energy storage, it includes parts that are similar to the parts of the first group of en- ergy storage. The second group includes a second stack 206 of several rechargeable storage batteries C12 to Cn2 with a second transformer 322. The storage batteries C12 to Cn2 are connected electrically in a series. Ά negative voltage terminal of the first battery C12 is connected to the electrical ground 236 while a positive voltage terminal of the battery Cn2 is connected to a stack terminal of the changeover switch U 2.

The second transformer 322 has a magnetic core 312 with a primary coil Np2 and with a plurality of secondary coils N12 to Nn2. The secondary coils N12 to Nn2 are connected to a plurality of secondary switches S12 to Sn2.

The primary coil Np2 is wound around the magnetic core 312. A first end A12 of the primary coil Np2 is connected to the stack terminal of the changeover switch UM2 while a second end A22 of the primary coil Npl is connected to the electrical ground 236 via a primary switch Spl2. Specifically, the second end A22 of the primary coil Np2 is connected to a transformer terminal of a primary switch Spl2. A ground terminal of the primary switch Spl2 is connected to the electrical ground 236. The primary switch Spl2 also includes a switching control in- put, which is connected to the microcontroller 213.

Each of the secondary coils N12 to Nn2 are wound around the magnetic core 312 and is connected in parallel to each of the corresponding storage batteries C12 to Cn2. The secondary coils N12 to Nn2 are connected to the corresponding storage batteries C12 to Cn2 via the corresponding secondary switches S12 to Sn2 in a manner that is similar to the connection be- tween the secondary coil Nil and the storage battery Cll via the secondary switch Sll.

The first changeover switch UM1 has a motor terminal, a fuel conversion unit terminal, and a driving battery assembly terminal. The motor terminal is connected to the motor 45. The fuel conversion unit terminal is connected to the fuel conversion unit while the driving battery terminal is connected to the driving battery assembly 45.

Similarly, the changeover switch U 2 has a second terminal and a third terminal. The said second terminal is connected to the node Kl while the said third terminal is connected to the node K2.

The driving battery assembly 42 includes a first group of energy storage and a second group of energy storage. The first group of energy storage is selectively connected to the fuel conversion unit and is selectively connected to the motor 45 via the first changeover switch U 1. Similarly, the second group of energy storage is selectively connected to the fuel conversion unit and is selectively connected to the motor 45 via the second changeover switch U 2. The fuel conversion unit includes the range extender 37 of the electric bicycle 10 with a dc-dc converter 214.

A voltage terminal of the range extender 37 is connected a first terminal of the dc-dc converter 214 while a ground ter- minal of the range extender 37 is connected to an electrical ground 236 via a current measuring circuit 216. A second terminal of the dc-dc converter 214 is connected to an electrical network node Kl, which is connected to a fuel conversion unit terminal of the first changeover switch UM1.

A voltage measuring circuit 215, which includes electrical circuits for energy management, is connected to a control input of the range extender 3 . The voltage measuring circuit 215 includes a voltage terminal and a ground terminal. The voltage terminal is connected to the node Kl while the ground terminal is connected to the electrical ground 236 via the current measuring circuit 216.

Referring to the motor 45, a voltage terminal of the motor 45 is connected to the node Kl while a ground terminal of the motor 45 is connected to the electrical ground 236 via the cur- rent measuring circuit 216.

Each of the storage batteries Cll to Cnl has a lithium ion battery. The storage batteries C12 to Cn2 have lithium ion batteries, which are similar to the lithium ion batteries of the storage batteries Cll to Cnl.

The variable n=10. Each of the storage batteries Cll to Cnl and each of the storage batteries C12 to Cn2 store a maximum electric charge at a voltage of 4 V (volts) . A typical power delivery of the electric drive system 203 ranges between 600 W (Watt) and 700 W, but can also extend to 4 or 5 kW (kilowatt) .

In a general sense, other buffer storage devices for energy can replace the transformers 321 and 322. These buffer storage devices may include capacitors, induction coils, or other further batteries. In use, the dc-dc converter 214 receives the voltage UB and generates an output voltage Ul in a manner that is in accordance to an adjustment input from the voltage measuring circuit 215. The dc-dc converter 214 acts to step up or down the volt- age UB to produce the output voltage Ul. In other words, the dc-dc converter 214 increases or decreases the voltage UB to produce the output voltage Ul. This said output voltage Ul is applied between the node Kl and the electrical ground 236. In one operating mode, the range extender 37 generates a voltage UB of about 24 V (volt) and the dc-dc converter 214 generates a voltage Ul of 40 V.

The voltage measuring circuit 215 measures a second voltage U2, which is applied between the node K2 and the electrical ground 236. This second voltage U2 is also applied to the motor 45. The energy management electrical circuit of the voltage measuring circuit receives measurement value of the second voltage U2 as well as information regarding expected energy consumption of the motor 45. The said circuit then provides the adjustment input to the dc-dc converter 214 according to the measurement value of the second voltage U2 and according to the expected energy consumption information. The changeover switch UMl alternates between two switching positions or states according to a state of its switching input, which is provided by the microcontroller 213.

In the first switching position, the changeover switch UMl connects the first terminal of the stack 205 to the node Kl . This effectively connects the stack 205 to the motor 45, wherein the stack 205 provides electrical energy to the motor 45 for driving for energizing the motor 45. This energizing also energizes peripheral circuits like engine control, gear control and user display, which are connected in parallel to the motor 45.

In the second switching position, the changeover switch UMl connects the first terminal of the stack 205 to the node K2. This effectively connects the stack 205 to the range extender 37 and to the dc-dc converter 214. In other words, the range extender 37 charges the stack 205 or the range extender 37 provides electrical energy to the stack 205.

In the same way, the changeover switch UM2 alternates between two switching positions according to a state of its switching input, which is provided by the microcontroller 213. In the first switching position, the changeover switch UM2 connects the first terminal of the stack 206 to the node Kl . In the second switching position, the changeover switch UM2 connects the first terminal of the stack 206 to the node K2.

The microcontroller 213 controls the changeover switches UMl and UM2 such that the switches UMl and UM2 adopt opposite switch positions. When the changeover switch UMl is in the first state, the changeover switch UM2 is in the second state and when the changeover switch UMl is in the second state, the changeover switch UM2 is in the first state. As a result, the range extender 37 charges one of the stacks 205 and 206 while the motor 45 drive another one of the stack 205 and 206. While one of the stacks 5 and 6 is being charged, no electrical current is taken from that stack 205 or 206 that is being charged. By doing this, the lifetime of the stacks 205 and 206 is increased.

It should be noted that during changing of the states of the changeover switches UMl and UM2, a short period of interruption of power supply could occur. Therefore, it is preferred to change the switching state during a halt of the vehicle.

The stack 205 receives energy or electrical charges from the range extender 37 via the changeover switch UMl and stores this energy in its storage batteries Cll to Cnl.

It is important to ensure that none of the storage batteries Cll to Cnl is overcharged. If an excessively high voltage is applied to one of the storage batteries Cll to Cnl, the said storage batteries then becomes defective with a result that the entire series of the storage batteries Cll to Cnl is unable to store electrical charges. The transformer 321 serves to transfer electrical energy from the range extender 37 to the storage batteries Cll to Cnl.

This is accomplished by the primary coil Npl of the transformer 321 receiving electromagnetic energy from the range extend- er 37 when the microcontroller 213 actuates the changeover switch UMl and the primary switch Spll to a closed state. When the changeover switch UMl is the closed state, the first terminal of the changeover switch UMl is connected to the third terminal of the changeover switch UMl. When the primary switch Spll is the closed state, the first terminal of the primary switch Spll is connected electrically to the second terminal of the primary switch Spll. The secondary coils Nil to Nnl then transfers this electromagnetic energy from the primary coil Npl to the storage batteries Cll to Cnl when the microcontroller 213 actuates the re- spectively Sll to Snl to a closed state.

In a general sense, the switches can be provided by solid- state elements, which have switching states. The state of the switch may be called a "position".

The table below shows different performance characteristics of storage batteries.

The table includes a column of storage battery age group data as well as a plurality of columns of data of storage battery performance. These performance data columns include a column of data of ranges of charge and discharge cycles, a column of data of expected minimum storage battery charge capacity, and a column of expected maximum storage battery charge differen- tial or deviation data for the corresponding age groups.

Storage Range of CyExpected Expected Maximum Battery cles of Minimum Charge DifferenAge Group Charging and Charge Catial/Deviation

Discharging pacity

I 0.0*X-0.1*X 99% 2.0%

II 0.1*X-0.2*X 90% 3.0%

III 0.2*X-0.4*X 80% 4.0%

IV 0.4*X-0.5*X 70% 4.5%

V 0.5*X-0.8*X 60% 5.0%

VI 0.8*X-0.9*X 55% 5 · 5%

VII 0.9*X-1.0*X 50% 5.5% The storage batteries, which include lithium ion batteries, have an expected lifetime or X number of cycles for charging and discharging. This X number of cycles can range from about 300 cycles to about 500 cycles and can even be up to about 2000 cycles in exceptional cases.

As shown by the table, as the X number of charging and discharging cycle increases, the charge capacity of the storage batteries reduces.

Furthermore, each storage battery usually has a different charge capacity. Even when subjecting the different storage batteries to a same number of cycles of charging and discharg- ing with active balancing, the various storage batteries often have different ageing processes because of their production differences. These different ageing processes cause the storage batteries to have different charge capacities. In the age group I, one stack of storage batteries has completed its first 0.1*X number of charge and discharge cycles, a charge capacity of any one of the storage batteries would then deviate or differ by less than 2% from an average charge capacity of the storage batteries.

Later, in the age group III, the stack of storage batteries has completed 0.2*X to 0.4*X number of charge and discharge cycles. The charge capacity of any one of the storage batteries would then differ by less than 4% from an average charge capacity of the storage batteries and the minimum charge capacity of the different storage batteries would be reduced to not less than 80% of its original charge capacity. Although the above description contains much specificity, these should not be construed as limiting the scope of the embodiments but merely providing illustration of the foreseeable embodiments. Especially the above stated advantages of the embodiments should not be construed as limiting the scope of the embodiments but merely to explain possible achievements if the described embodiments are put into practise. Thus, the scope of the embodiments should be determined by the claims and their equivalents, rather than by the examples given.

The embodiments can also be described with the following lists of elements being organized into items. The respective combinations of features which are disclosed in the item list are regarded as independent subject matter, respectively, that can also be combined with other features of the application.

1. A portable range extender for supplying electrical energy to a lightweight electric vehicle, the portable range extender comprising

a dynamoelectric machine for electrically coupling to an energy storage device,

an internal combustion engine for converting combustible fuel to electrical energy, the internal combustion engine is coupled to the dynamoelectric machine by a shaft,

a port for transmitting electric energy generated by the dynamoelectric machine, and

a controller for receiving at least one input, wherein in response to the input, the range extender provides a first mode, a second mode, and a third mode - such that in the first mode, the dynamoelectric machine receives electrical energy from the energy storage device to rotate the shaft,

- such that in the second mode, the internal combus tion engine converts the combustible fuel to electrical energy for rotating the shaft, and

- such that in the third mode, the dynamoelectric machine generates electrical energy.

The portable range extender according to item 1, wherein the combustible fuel comprises Liquefied Petroleum Gas (LPG) .

The portable range extender according to item 2 further comprising a valve for controlling release of the LPG to the internal combustion engine.

The portable range extender according to item 3 further comprising a valve for controlling release of air for mixing with the LPG.

The portable range extender according to one of aforemen tioned items further comprising a microphone for detecting an operational status of the internal combustion engine .

The portable range extender according to one of aforemen tioned items further comprising at least one temperature sensor . The portable range extender according to item 6, wherein the temperature sensor is provided at a fuel inlet of the internal combustion engine. The portable range extender according to item 6, wherein the temperature sensor is provided at an exhaust outlet of the internal combustion engine. The portable range extender according to item 6, wherein the temperature sensor is provided at a cylinder head of the internal combustion engine. The portable range extender according to one of aforementioned items further comprising an oxygen sensor. The portable range extender according to one of aforementioned items further comprising a shaft speed sensor. The portable range extender according to one of aforemen- tioned items further comprising at least one strain gauge for detecting an operational status of the internal combustion engine or the dynamoelectric machine. The portable range extender according to one of aforemen- tioned items further comprising a resistor for consuming electrical energy generated by the dynamoelectric machine.

The portable range extender according to one of aforementioned items, wherein the portable range extender provides the first mode, the second mode, and the third mode upon receiving a first pre-determined energy data of the energy storage device. The portable range extender according to item 14, wherein the second mode is provided after the first mode and the third mode is provided after the second mode. The portable range extender according to one of aforementioned items, wherein

the portable range extender further provides a standby mode, the portable range extender enters the standby mode upon receiving a second pre-determined energy data of the energy storage device. The portable range extender according to one of aforementioned items, wherein

the portable range extender further provides an abnormal mode, the portable range extender enters the abnormal mode upon receiving an abnormal sensor data. The portable range extender according to one of the aforementioned items, wherein the portable range extender comprises a secondary generator with a thermoelectric generator, wherein a heating portion of the thermoelectric generator is in thermal contact with an exhaust pipe of the portable range extender. The portable range extender according to one of the aforementioned items, wherein the portable range extender comprises a secondary generator with a heat difference driven engine, wherein a heating portion of the heat dif- ference driven engine is in thermal contact with an exhaust pipe of the portable range extender. A lightweight electric vehicle comprising

a portable range extender according to one of aforementioned items,

an energy storage device for providing electrical energy to the portable range extender and for receiving electrical energy from the portable range extender, and a motor for receiving electrical energy from the energy storage device to drive at least one wheel of the lightweight vehicle.

Reference

10 bicycle 65 dynamoelectric machine

12 frame 67 shaft

13 motor assembly 69 concrete panel casing

14 transmission assembly 71 variable resistor

16 top tube 72 secondary generator

17 head tube 73 cylinder head

19 seat tube 74 glow plug

20 down tube 75 cooling fins

23 seat stay tube 76 combustion mixture in¬

25 chain stay tube let

28 front wheel 77 engine gas exhaust pipe

29 fork 78 transformer

31 rear wheel 79 cylinder temperature

33 handle bar assembly sensor

35 seat 81 engine temperature sen¬

37 range extender sor

39 controller 83 exhaust window

42 driving battery assem85 heat tolerant tube

bly 86 exhaust temperature

45 driving motor sensor

47 front sprocket assembly 88 lambda sensor

48 rear sprocket assembly 90 piping assembly

50 chain 92 LPG container

55 CAN bus 94 pipe

57 power-on button 96 valve

58 power-off button 97 actuator

59 display unit 100 valve

61 microphone 102 actuator

63 internal combustion en104 combustion-mixture temgine perature sensor inlet air window AG1 age group

outlet air window AG2 age group

inlet air fan Cll storage battery outlet air fan C12 storage battery motor shaft rotation C21 storage battery sensor C22 storage battery strain gauge C31 storage battery range extender state C32 storage battery diagram LI charge state

offline state L2 charge state

standby state Npl primary coil

charge generation state Np2 primary coil

abnormal state Nil first secondary coil

Stirling engine N12 first secondary coil

Seebeck effect device N21 second secondary coil electric drive system N22 second secondary coil stack N31 third secondary coil stack N32 third secondary coil microcontroller Spll primary switch

DC-DC converter Spl2 primary switch

voltage measuring cirSll switch

cuit S21 switch

current measuring cirS12 switch

cuit S22 switch

ground S32 Switch

core Ul first voltage

core U2 second voltage

transformer UB fuel cell voltage transformer UM1 first changeover switch

UM2 second changeover first terminal switch

Claims

a dynamoelectric machine for electrically coupling to an energy storage device,

an internal combustion engine for converting combustible fuel to electrical energy, the internal combustion engine is coupled to the dynamoelectric machine by a shaft.,

a controller for receiving at least one input, wherein in response to the input, the range extender provides a first mode, a second mode, and a third mode

- such that in the first mode, the dynamoelectric machine receives electrical energy from the energy storage device to rotate the shaft,

- such that in the second mode, the internal combustion engine converts the combustible fuel to electrical energy for rotating the shaft, and

2. The portable range extender according to claim 1, wherein

the combustible fuel comprises Liquefied Petroleum Gas (LPG) . The portable range extender according to claim 2 furthe comprising a valve for controlling release of the LPG t the internal combustion engine. The portable range extender according to claim 3 further comprising a valve for controlling release of air for mixing with the LPG.

The portable range extender according to claim 1 further comprising a microphone for detecting an operational status of the internal combustion engine.

The portable range extender according to claim 1 further comprising at least one temperature sensor.

The portable range extender according to claim 6, wherein the temperature sensor is provided at a fuel inlet of the internal combustion engine.

The portable range extender according to claim 6, wherein the temperature sensor is provided at an exhaust outlet of the internal combustion engine.

The portable range extender according to claim 6, wherein the temperature sensor is provided at a cylinder head of the internal combustion engine.

The portable range extender according to one of aforementioned claims further comprising an oxygen sensor.

The portable range extender according to claim 1 further comprising a shaft speed sensor. The portable range extender according to claim 1 furthe comprising at least one strain gauge for detecting an operational status of the internal combustion engine or the dynamoelectric machine .

The portable range extender according to claim 1 furthe comprising a resistor for consuming electrical energy generated by the dynamoelectric machine.

The portable range extender according to claim 1, where in the portable range extender provides the first mode, the second mode, and the third mode upon receiving a first pre-determined energy data of the energy storage device.

The portable range extender according to claim 14, wherein

the second mode is provided after the first mode and the third mode is provided after the second mode.

The portable range extender according to claim 1, wherein

the portable range extender further provides a standby mode, the portable range extender enters the standby mode upon receiving a second pre-determined energy data of the energy storage device.

17. The portable range extender according to claim 1, wherein the portable range extender further provides an abnormal mode, the portable range extender enters the abnormal mode upon receiving an abnormal sensor data.

The portable range extender according to claim 1, wherein the portable range extender comprises a secondary generator with a thermoelectric generator, wherein a heating portion of the thermoelectric generator is in thermal contact with an exhaust pipe of the portable range extender.

The portable range extender according to claim 1, wherein the portable range extender comprises a secondary generator with a heat difference driven engine, wherein a heating portion of the heat difference driven engine is in thermal contact with an exhaust pipe of the portable range extender.

A lightweight electric vehicle comprising

a portable range extender according to claim 1, an energy storage device for providing electrical energy to the portable range extender and for receiving- electrical energy from the portable range extender, and a motor for receiving electrical energy from the energy storage device to drive at least one wheel of the lightweight vehicle.