Hybrid electric vehicle

Abstract

A hybrid electric vehicle includes a high voltage DC bus and an internal combustion engine. The internal combustion engine is mechanically coupled to a non self-excited generator/motor which is preferably a switched reluctance machine. A power inverter electrically and bidirectionally couples the high voltage DC bus to the non self-excited switched reluctance generator/motor. Front and rear axle dual DC-AC inverters electrically and bidirectionally couple two traction AC non self-excited switched reluctance motors/gear reducers to the high voltage DC bus for moving the vehicle and for regenerating power. An ultracapacitor coupled to the high voltage DC bus. A bidirectional DC-DC converter interposed between a low voltage battery and the high voltage DC bus transfers energy to the high voltage DC bus and ultracapacitor to ensure that the non self-excited switched reluctance generator/motor operating in the motor mode is able to start the engine.

Claims

1. A series-electric hybrid vehicle, comprising: a non self-excited generator/motor for providing power to said vehicle for propulsion and operation thereof; a high voltage DC bus; a plurality of wheels which propel said vehicle; one or more non self-excited AC traction motors/generators; one or more compact dual inverters convey power bi-directionally between said high voltage DC bus and said one or more non self-excited AC traction motors/generators which are affixed, respectively, to one or more of said plurality of wheels; said compact dual inverters associated with said non self-excited AC traction motors/generators are configured to operate in a generator mode or in a motor mode; said non self-excited AC traction motors/generators are configured in combination with said wheels to provide propulsion and regenerative braking; an internal combustion engine; said internal combustion engine coupled to said non self-excited generator/motor for providing power to said vehicle for propulsion and operation thereof; said non self-exciting generator/motor coupled to an inverter; said inverter supplies power bidirectionally to and from said high voltage DC bus, said inverter supplies power to said high voltage DC bus when said non self-excited generator/motor operates in said generator mode, and, said inverter supplies power to said non self-excited generator/motor when said non self-excited generator/motor operates in said motor mode; an ultracapacitor bank, said ultracapacitor bank electrically coupled to said high voltage DC bus; said ultracapacitor bank stores regenerative energy from said non self-excited AC traction motors when operating in said motor mode; and, said ultracapacitor bank supplies energy to said inverter coupled to said non self-excited generator/motor operating in said motor mode for starting said internal combustion engine; a conventional low voltage system with at least one 12 or 24 volt DC battery; a bidirectional DC-DC converter to convey power between said 12 or 24 volt DC battery and said ultracapacitor bank for purposes of pre-charging said ultracapacitor bank to start said internal combustion engine and to maintain the state of charge of said 12 or 24 volt battery after said internal combustion engine is started.

2. A series-electric hybrid vehicle as claimed in claim 1, further comprising: a resistor bank, said resistor bank dissipates excess regenerative energy from said non self-excited AC traction generators/motors operating in said generator mode.

3. A series-electric hybrid vehicle as claimed in claim 1 in which said non self-excited generator/motor operating in said motor mode is used to dissipate excess kinetic energy from said vehicle by back driving said internal combustion engine while operating an engine compression brake.

4. A hybrid electric vehicle, comprising: a high voltage DC bus; an internal combustion engine; said internal combustion engine driving a non self-excited generator/motor supplying energy to said high voltage DC bus; a rear axle compact bidirectional dual DC-AC inverter driving two AC motors/generators/gear reducers for moving said vehicle and for recapturing energy from regenerative braking; a front axle compact bidirectional dual DC-AC inverter driving two AC motors/generators/gear reducers for moving said vehicle and for recapturing energy from regenerative braking; at least one 12-volt or 24-volt DC battery; an ultracapacitor, said ultracapacitor electrically coupled to said high voltage DC bus; a bidirectional DC-DC converter interposed between said 12 or 24-volt battery and said high voltage DC bus, said DC-DC converter transfers energy between said 12 or 24-volt DC battery and said high voltage DC bus and said ultracapacitor; said non self-exciting generator/motor coupled to said engine for starting said internal combustion engine; and, said ultracapacitor supplying energy to said inverter coupled to said generator for starting said internal combustion engine.

5. A hybrid electric vehicle as claimed in claim 4, further comprising: a resistor bank; and, said compact dual bidirectional DC-AC inverters include rectification means for regenerating energy and storing said energy in said at least one battery and/or said ultracapacitor.

6. A series-electric hybrid vehicle as claimed in claim 1 wherein said non self-exciting generator/motor is a switched reluctance machine.

7. A series-electric hybrid vehicle as claimed in claim 1 wherein said non self-exciting generator/motor is the primary source of electrical energy for the vehicle.

8. A hybrid electric system, comprising: an internal combustion engine; a non self-exciting AC generator/motor; said non self-exciting AC generator/motor operates in either a generator mode or a motor mode; a high voltage DC bus; an ultracapacitor bank, said ultracapacitor bank connected full time across said high voltage DC bus; an AC-DC inverter for converting the AC power from said non self-exciting AC generator/motor to DC power for supply to said high voltage DC bus and said ultracapacitor bank; a low voltage DC battery; means for charging said ultracapacitor bank from said conventional low-voltage vehicle DC battery to provide initial excitation energy to said non self-exciting generator/motor operating in said motor mode to start said internal combustion engine.

9. A hybrid electric system as claimed in claim 8, further comprising: dual compact inverters; a plurality of wheels; a plurality of non self-excited traction generators/motors each interconnected with a respective one of said plurality of wheels; said dual compact inverters are connected across said ultracapacitor bank; said dual compact inverters are bidirectional DC-AC inverters; and, said dual compact inverters transfer energy to and from said ultracapacitor bank and to and from said non self-excited traction generators/motors.

10. A hybrid electric system as claimed in claim 8, wherein said non self-excited generator/motor is operated in said motor mode to back drive said internal combustion engine and an associated engine brake in order to dissipate excessive regenerative braking energy.

11. A hybrid electric system as claimed in claim 8 wherein said ultracapacitor bank is driven to a predetermined maximum state of charge prior to engine shutdown in order to provide for rapid engine starting without need to rely on pre-charging from said vehicle low-voltage DC battery under normal operating conditions.

12. A hybrid electric system as claimed in claim 8 wherein said means for charging said ultracapacitor bank from said conventional low voltage vehicle DC battery to provide initial excitation energy to said non self-exciting generator/motor operating in said motor mode to start said internal combustion engine.

13. A hybrid electric system as claimed in claim in claim 9 in which one or more of said dual compact inverters discharge some energy in said ultracapacitor bank into the windings of said non self-excited traction generators/motors without motion either by operating at sufficiently low enough power to avoid motion or by operating said non self-excited traction generators/motors with opposing torques to enable safe operation of said system.

14. A hybrid electric system, comprising: a non self-excited generator/motor coupled to an internal combustion engine; said non self-excited generator/motor is operable in a generator mode or a motor mode; a power inverter; a high voltage DC bus; an ultracapacitor interconnected with said high voltage DC bus; a low voltage battery; a DC-DC bidirectional converter; said ultracapacitor bank is charged to a usable operating voltage by transferring energy from said low voltage battery by use of said DC-DC converter; said non self-excited generator/motor is driven by said power inverter to start said internal combustion engine when said ultracapacitor is charged to a usable voltage and when said non self excited generator/motor is in said motor mode.

15. A hybrid electric system as claimed in claim 14 wherein said DC-DC converter charges said low voltage battery once said internal combustion engine is operational.

16. A hybrid electric system as claimed in claim 14 further comprising a traction motor.

17. A hybrid electric system as claimed in claim 15 further comprising a plurality of traction motors.

18. A hybrid electric system as claimed in claim 16 wherein said traction motors may be selected from the group of self-exciting interior permanent magnet motors, non-self-exciting, AC or DC motors.

19. A hybrid electric system as claimed in claim 17 wherein said traction motors may be selected from the group of self-exciting interior permanent magnet motors, non-self-exciting, AC or DC motors.

20. A hybrid electric vehicle, comprising: a controller; a non self-excited generator/motor mechanically interconnected with said internal combustion engine; a power inverter; said non self-excited generator/motor in electrical communication with said power inverter; said non self-excited generator/motor is operable in a generator mode or a motor mode; a high voltage DC bus; an ultracapacitor interconnected with said high voltage DC bus; said controller in electrical communication with said power inverter controlling said power inverter; a low voltage battery; a DC-DC bidirectional converter; said ultracapacitor bank is charged to a usable operating voltage by transferring energy from said low voltage battery by use of said DC-DC converter; and, said non self-excited generator/motor is controlled by said controller and driven in said motor mode by said power inverter when said ultracapacitor is charged to a usable voltage to start said internal combustion engine.

21. A hybrid electric vehicle as claimed in claim 20, further comprising: a first dual compact inverter and a second dual compact inverter; a plurality of non self-excited traction generators/motors driven by said first and second dual compact inverters; said first and second compact inverters controlled by said controller.

22. A hybrid electric vehicle as claimed in claim 21 wherein said first and second dual compact inverters may bidirectionally supply power.

23. A hybrid electric vehicle as claimed in claim 21 wherein said power inverter may bidirectionally supply power.

24. A hybrid electric vehicle as claimed in claim 21 wherein said first and second dual compact inverters may bidirectionally supply power and wherein said power inverter may bidirectionally supply power.

25. A series-electric hybrid vehicle comprising: an internal combustion engine that converts chemical energy into mechanical energy; a non-self-excited generator/motor coupled to said internal combustion engine to convert mechanical power to electric power and provide said electric power to said vehicle for propulsion; a high-voltage DC bus; an inverter to transfer power bi-directionally between said non-self-excited generator/motor and said high-voltage DC bus; a traction motor/generator that provides propulsion power; an inverter to transfer electric power bi-directionally between said traction motor/generator and said high-voltage DC bus; a conventional low-voltage system with at least one 12 or 24 volt battery; an ultracapacitor bank, said ultracapacitor bank electrically coupled to said high-voltage DC bus; a bidirectional DC-DC converter to convey power between said 12 or 24 volt battery and said ultracapacitor bank for purposes of pre-charging said ultracapacitor bank when necessary to provide sufficient energy to excite said generator and start said internal combustion engine using said non self excited generator/motor operating in said motor mode and thereafter to maintain the state of charge of said low-voltage battery once said internal combustion engine is operating; and, control logic, said control logic manages the state of charge of said ultracapacitor bank and the propulsive operation of said vehicle and other related functions.

26. A hybrid electric system, as claimed in claim 8, further comprising a DC-AC inverter for powering an AC traction motor for powering said vehicle.

27. A hybrid electric system as claimed in claim 26, wherein said AC traction motor operates as a generator regenerating energy to said DC-AC inverter for storage in said ultracapacitor.

28. A hybrid electric vehicle as claimed in claim 20, further comprising: a first inverter; a traction generator/motor driven by said first inverter; and, said first inverter controlled by said controller.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1A is schematic illustration of a hybrid electric vehicle illustrating, inter alia, the condition wherein the capacitor is charged from the 24-volt batteries after a prolonged shut-down of the hybrid electric vehicle.

(2) FIG. 1B is a schematic illustration of a hybrid electric vehicle illustrating, inter alia, the condition wherein the capacitor is sufficiently charged and supplying energy to the non self-exciting switched reluctance generator/motor to start the internal combustion engine.

(3) FIG. 1C schematic illustration of a hybrid electric vehicle illustrating, inter alia, the condition wherein the internal combustion engine is supplying power to the non self-exciting switched reluctance generator/motor operating in the generator mode supplying power to the ultra capacitor bank, the DC-DC converter and the 24 volt batteries.

(4) FIG. 1D is a schematic illustration of a hybrid electric vehicle illustrating, inter alia, the condition wherein the internal combustion engine is supplying power to the non self-exciting switched reluctance generator/motor operating in the generator mode which, in turn, is supplying power to the ultra capacitor bank, the dual inverters which supply power to the traction motors, and to the DC-DC converter supplying the low voltage batteries.

(5) FIG. 1E is a schematic illustration of a hybrid electric vehicle illustrating, inter alia, the condition wherein the regenerative power is being supplied to the ultracapacitor bank, DC-DC converter, and the low-voltage batteries.

(6) FIG. 1F is a schematic illustration of a hybrid electric vehicle illustrating, inter alia, the condition wherein the regenerative power is being supplied to the ultracapacitor bank and the non self-exciting switched reluctance generator/motor operating in the motor mode.

(7) FIG. 1G is schematic illustration of a hybrid electric vehicle without an ultracapacitor bank wherein the low voltage batteries are used with an engine starter for starting the internal combustion engine.

(8) FIG. 1H is a schematic illustration of a dual compact inverter having a synergistic advantage in that the inverters are able to share the cold plate, a DC-Link capacitor bank, bus bars, housing, high voltage connector and wiring and some of the low voltage electronics.

(9) FIGS. 2 and 2A is a schematic of the control strategy of the hybrid electric vehicle.

(10) FIG. 3 is an electrical schematic implementing the control strategy of FIGS. 2 and 2A.

(11) FIG. 4 is a graph illustrating the ultracapacitor voltage versus the ultracapacitor total stored energy.

(12) FIG. 5 is a graph illustrating ultracapacitor usable energy versus the charge time.

(13) FIG. 6 is a graph illustrating vehicle speed versus kinetic energy for a 30,000 kg and a 40,000 kg vehicle.

(14) FIG. 7 is a graph illustrating vehicle speed, time and conditions for regeneration of energy.

(15) FIG. 8 is a semi-log graph of ultracapacitor voltage versus time for discharge for different power levels.

DESCRIPTION OF THE INVENTION

(16) FIG. 1A is schematic illustration 100A of a hybrid electric vehicle illustrating, inter alia, the condition wherein the ultracapacitor bank 104 is charged from the 24-volt batteries 107 after a prolonged shut-down of the hybrid electric vehicle. FIGS. 1A-1H, inclusive, use many of the same reference numerals and they have the same meaning. Once an element is described in connection with a given reference numeral it will generally not be described again in connection with a subsequent drawing figure to avoid repetition. Reference numeral 161 indicates a dashed line illustrating energy flow along path 161 from the low voltage batteries 107 through the DC-DC converter 106 to the ultracapacitor bank 104, the bidirectional power inverter 103, and the non self-excited switched reluctance generator/motor operating in the motor mode and to the internal combustion engine 101. DC-DC converter 106 is capable of handling 5 kW of power. If the ultracapacitor bank is charged to a sufficient energy level as represented by the voltage across the ultracapacitor/high voltage DC bus, then the non self-excited switched reluctance generator/motor operating 102 in the motor mode may be operated so as to protect the low-voltage batteries from an over-current situation. The ultracapacitor bank 104 and the high voltage DC bus are at the same voltage at all times as they are physically connected. The non self-excited switched reluctance generator/motor operating in the motor mode is mechanically coupled to the internal combustion engine 101. Reference numeral 163M is a schematic arrow indicating rotational energy applied to the crank shaft of the internal combustion engine 101 by the switched reluctance generator/motor 102 operating in the motor mode.

(17) As used herein the terms ultracapacitor bank 104 mean the same as ultracapacitor or ultra-capacitor. In the preferred embodiment or example, the ultracapacitors are arranged in series to achieve 1200 Farads of capacitance. Preferably the ultracapacitor bank has an acceptable operational range over which energy is stored. Capacitances in series do not add, rather, capacitances in series are calculated as follows:

(18) It is specifically contemplated that ultracapacitors may be used in parallel, series or in a combination of parallel and series. Further, it is specifically contemplated that capacitances may be in the range of between 1200-3000 F. FIG. 4 is a graph 400 illustrating the ultracapacitor voltage 401 versus the ultracapacitor total stored energy 402. A line representing 650 F of capacitance 403, a line representing 1200 F of capacitance 404, a line representing 1500 F of capacitance 405, a line representing 2000 F of capacitance, and a line representing 3000 F of capacitance are illustrated in FIG. 4. Reference numeral 408 indicates the lower ultracapacitor operational voltage of 500 V DC and reference numeral 409 indicates the upper ultracapacitor operational voltage of 800 V DC.

(19) Still referring to FIG. 1A, a non self-excited switched reluctance generator/motor 102 is illustrated therein along with an internal combustion engine 101. The terms non self-excited and non self-exciting as used herein mean the same thing. A bidirectional power inverter communicates 103A electrical power to and from the high voltage DC bus 105. The switched reluctance generator/motor 102 produces AC power and the bidirectional inverter 103 converts AC power to DC power and vice-versa. High voltage DC bus 105 is interconnected 104A with ultracapacitor bank 104, DC-DC converter 106, and compact dual inverters 108, 109.

(20) First compact dual inverter 108 drives AC switched reluctance motors/generators 110, 111 which operate in the motor mode for driving the front wheels of the hybrid electric vehicle. First compact dual inverter 108 may also receive energy from the AC switched reluctance traction motors/generators 110, 111 when they operate in the generator mode. Reference numerals 110A, 111A indicate bidirectional power or energy flow between the AC switched reluctance motors/generators 110, 111 and the first compact dual inverter 108. Reference numerals 112A, 113A indicate bidirectional power or energy flow between the AC switched reluctance motors/generators 112, 113 and the second compact dual inverter 109.

(21) Second compact dual inverter 109 drives AC switched reluctance motors/generators 112, 113 operating in the motor mode for driving the rear wheels of the hybrid electric vehicle. Second compact dual inverter 109 may also receive energy from the AC switched reluctance traction motors/generators 112, 113 operating in the generator mode.

(22) Reference numeral 108A illustrates the bidirectional interconnection between the high voltage DC bus 105 and first compact dual inverter 108. Reference numeral 109A illustrates the bidirectional interconnection between the high voltage DC bus 105 and the second compact inverter 109.

(23) FIG. 1B is a schematic illustration 100B of a hybrid electric vehicle illustrating, inter alia, the condition wherein the capacitor 104 is sufficiently charged and supplying energy to the non self-exciting switched reluctance generator/motor 102 to start the internal combustion engine. Reference numeral 162M is used to identify the charge flow from the ultracapacitor bank 104 to the DC/AC inverter 103 and to the non self-excited switched reluctance generator/motor 102 operating in the motor mode. Reference numeral 163M illustrates a schematic arrow indicating rotational energy applied to the crank shaft of the internal combustion engine 101 by the switched reluctance generator/motor 102 operating in the motor mode.

(24) FIG. 1C is a schematic illustration 100C of a hybrid electric vehicle illustrating, inter alia, the condition wherein the internal combustion engine 101 is supplying power to the non self-excited switched reluctance generator/motor 102 operating in the generator mode supplying power to the ultracapacitor bank 104, the DC-DC converter 105, and the 24 volt batteries 107. Reference numeral 163G is a schematic arrow indicating rotational energy supplied by the crank shaft of the internal combustion engine 101 to the switched reluctance generator/motor 102 operating in the generator mode. The internal combustion engine 101 may be a 10.8 liter diesel engine. The switched reluctance generator/motor 102 operating in the generator mode may be a 227 kW machine. Reference numeral 162G illustrates charge flow from the non self-exciting switched reluctance generator/motor 102 operating in the generator mode to: the DC/AC inverter 103, the ultracapacitor bank 104, the DC-DC converter 106, the low-voltage batteries 107, the compact dual inverters 108, 109, and the non self-excited traction motors/gear reducers 110, 111, 112, and 113 for driving wheels of the hybrid vehicle. The non self-excited traction motors/gear reducers 110, 111, 112, and 113 for driving wheels of the hybrid vehicle may be 65 kW switched reluctance motors are illustrated schematically in FIG. 1C. See FIG. 1D, a schematic illustration 100D of a hybrid electric vehicle illustrating, inter alia, the condition wherein the internal combustion engine 101 is supplying power to the non self-exciting switched reluctance generator/motor 102 operating in the generator mode which, in turn, is supplying power to the ultra capacitor bank 104, the dual compact inverters 108, 109 which supply power to the non self-exciting AC traction motors/generators 110, 111, 112, 113, and to the DC-DC converter 106 supplying the low voltage batteries 107. Referring to FIG. 1D, reference numeral 162G illustrates the energy flow from the ultracapacitor and/or the high voltage DC bus to the compact dual inverters 108, 109, and to the non self-excited traction generators/motors/gear reducers 110, 111, 112, and 113 for driving wheels of the hybrid vehicle. The non self-excited traction generators/motors/gear reducers are affixed to driving wheels of the hybrid vehicle. Gear reduction is used to convert high-speed, low-torque, power from the traction motors into low-speed, high-torque power at the wheel ends.

(25) Referring to FIG. 1H, dual compact inverter is illustrated which has a synergistic advantage in that two inverters are able to share a cold plate, a DC-Link capacitor bank, bus bars, housing, high voltage connector and wiring and some of the low voltage electronics. This results in saving space and in increased efficiency.

(26) Referring again to FIG. 1D, reference numeral 163G illustrates the mechanical rotational energy flowing from the internal combustion engine generating electrical AC power from the non self-exciting switched reluctance generator/motor 102 whereby it its inverted to DC power by bidirectional power inverter 103. The DC power is then stored in the ultracapacitor bank 104 and/or it is used by the vehicle. If the DC power is used by the vehicle, the compact dual inverters 108, 109 invert the DC power to AC power to operate the non self-exciting AC traction motors/generators 110, 111, 112, 113 and to power the vehicle. Although not specifically illustrated with a dashed line on FIG. 1D, it is also possible that the DC-DC converter is being used to convert the higher voltage of the high voltage DC bus to charge the low voltage DC batteries. It is desired to maintain the high voltage DC bus and the ultacapacitor bank at a voltage between 500-800 VDC.

(27) FIG. 1E is a schematic illustration 100E of a hybrid electric vehicle illustrating, inter alia, the condition wherein the regenerative power is being supplied to the ultracapacitor bank 104, DC-DC converter 106, and the low-voltage batteries 107. Reference numeral 162R indicates dashed lines which are representative of power flow to the ultracapacitor from the non self-exciting AC traction motors/generators 110, 111, 112, and 113. More specifically, reference numeral 162R indicates charge flow from the non self-exciting switched reluctance generator/motors 110, 111, 112, and 113 acting in the generator mode to the compact dual AC/DC inverters 108, 109, the high voltage DC bus 105, and the ultracapacitor bank 104. As set forth in FIG. 1E, the non self-excited switched reluctance generator/motor 102 may be operating and may be idling.

(28) Room for regenerative energy storage must be made in the ultracapacitor bank as set forth in FIG. 1E. An electronic controller as set forth in FIG. 3 controls the operation of the hybrid electric vehicle. FIG. 3 is an electrical schematic 300 implementing the control strategy of FIGS. 2 and 2A. FIGS. 2 and 2A is a schematic 200, 200A of the control strategy of the hybrid electric vehicle. Referring to FIG. 2, reference numeral 203 represents the query: is the key in start position? The encircled A is a terminal representing inputs and outputs to the controller 301 which controls the process of operating the hybrid electric vehicle. The DC-DC converter is a 4-port device. Two of the lines are connected (full time) in parallel across the 12/24 volt batteries and the other two lines are connected (full time) across the high voltage bus. Like an alternator, the DC-DC converter is a current device. In response to commands from the vehicle control unit it takes current from one of the voltage sources and delivers it to the opposite voltage source. In this example, there are 8 switches. No more than four switches should ever be turned on simultaneously (or damage will result). In standby mode all of the switches will be off. The control of the traction motors is strictly in response to the driver requirements for traction or braking, without regard to system energy or DC-Link voltage, with the following exceptions: 1) The associated inverters are not capable of operating below some minimum voltage (e.g. 500V) so the motors will cease operating if this occurs; 2) The ultracapacitor bank and power inverters will suffer damage if the DC-Link voltage exceeds 900 volts, so delivery of regenerated energy must be halted at some upper voltage limit. The hybrid controller will control the generator inverter to provide current to the DC-Link bus such that: 1) The DC-link voltage stays above the minimum inverter operating voltage; 2) The ultracapacitor bank voltage is kept as high as possible (short of the 900V limit with a safety margin) provided it retains sufficient storage capability to recapture any kinetic or potential energy currently stored in the vehicle. That is because a higher DC-link voltage results in lower system currents, and thus lower losses; hence better system efficiency; 3) The ultracapcitor bank is fully charged prior to engine shutdown so that, even if the ultracapacitors discharge over time, they will likely retain sufficient energy to restart the engine.

(29) If the vehicle is not running, the internal combustion engine must be started. The controller queries the energy status of the ultracapacitor bank to determine if there is sufficient energy 205 in the ultracapacitor bank 104 to start the internal combustion engine. If there is not sufficient energy 205 in the ultracapacitor bank 104 to start the engine, then proceed to step 210 and transfer energy (charge) to the ultracapacitor bank 104 to charge it preferably to at least 200V DC. Reference numeral 211 indicates a line indicating communication of energy to the ultracapacitor bank where the query of whether or not there is sufficient energy 205 is again made. More specifically, if there is sufficient energy 205 in the ultracapacitor bank to start the engine, then proceed to step 203 and position the key in the start position. Once the start command has been made, communication 203Y is made with the internal combustion engine to determine if it is running 204. If the internal combustion engine is running 204Y then a calculation is made to determine the recoverable energy in the vehicle 207. If the internal combustion engine is not running 204N, then the key is once again positioned in the start position to attempt to start the internal combustion engine 101.

(30) Once the calculation is made to determine the recoverable energy in the vehicle 207, and communicated 207A to the next step 208, then the controller adds the recoverable energy, Er, to the energy in the ultracapacitor bank to determine if that sum is less than the maximum permissible amount of energy in the ultracapacitor bank 208. If the energy comparison of step 208 satisfies the required inequality, to wit, that the recoverable energy of the vehicle, Er, plus the energy presently stored in the ultracapacitor bank, Euc, is less than the maximum permissible energy in the ultracapacitor bank, Euc-max 208Y, then the internal combustion engine 101 is set to the best brake specific fuel consumption and maximum generator 102 power is commanded 214 by the controller.

(31) If the energy comparison of step 208 does not satisfy the required inequality, to wit, that the recoverable energy of the vehicle, Er, plus the energy presently stored in the ultracapacitor bank, Euc, is not less that the maximum permissible energy in the ultracapacitor bank, Euc-max, 208N, then the internal combustion engine 101 is commanded to idle and the output of the switched reluctance generator/motor 102 operating in the generator mode is commanded to zero generator current. Then, this condition is communicated 216Y to the controller 216Y and the hybrid electric vehicle burns off (consumes/dissipates) energy stored in the ultracapacitor 104. A wait time 217 is initiated for the energy burn. If the wait time expires 217Y and sufficient energy has not been burned, then the internal combustion engine is shutdown 218. During the wait time, the controller is periodically checking (sampling) the data and making the energy comparison step 208.

(32) Referring to FIG. 2A, when the internal combustion engine 101 is set to the best brake specific fuel consumption and maximum generator 102 power is commanded 214 by the controller, the controller communicates that condition 215 to the next step 235, and the query: is the brake command present 221 is made. The brake command is present when the operator of the vehicle is depressing the brake pedal of the hybrid electric vehicle. If the brake command is present 221Y, then proceed to the next step 227, and send a negative torque command 227 to the non self-exciting switched reluctance generator/motors 110, 111, 112, and 113 acting in the generator mode via the compact dual AC/DC inverters 108, 109.

(33) If the brake command is not present 221, then proceed to the next step 222, is the DC Link voltage>DC Link Min voltage? The DC Link is the high voltage bus 105. If the DC Link voltage is not greater than the DC link Min voltage, then communicate this condition 222N and proceed to the next step 228 and send zero torque command to the switched reluctance generators/motors 110, 111, 112, 113 which drive the vehicle wheels proportional to the accelerator signal and within stability limits. The DC Link voltage is the same thing as the high voltage DC bus.

(34) If the DC Link voltage is greater than the DC link minimum voltage 227Y, then proceed to the next step 223, and read the accelerator command from the electronic controller. Next, the shift selector is read and the query 225 of: is the speed of the vehicle less than the maximum speed for the selector position? If the speed of the vehicle is not less than the maximum speed for the selector position 225N, then proceed to the next step 228 and send zero torque command to the switched reluctance generators/motors 110, 111, 112, 113 which drive the vehicle wheels.

(35) If the speed of the vehicle is less than the maximum speed for the selector position 225Y, then proceed to the next step 226, is the hybrid electric vehicle in forward gear 226? If the vehicle is not in forward gear 226N, then proceed to the next step 230 and send a negative torque command to the switched reluctance generators/motors 110, 111, 112, 113 which drive the vehicle wheels proportional to the accelerator signal and within stability limits to drive the vehicle in the backward (rearward) direction. If the vehicle is in forward gear 226Y, proceed to the next step 229 and send a positive torque command to the switched reluctance generators/motors 110, 111, 112, 113 which drive the vehicle wheels proportional to the accelerator signal and within stability limits to drive the vehicle in the forward direction.

(36) FIG. 1F is a schematic illustration 100F of a hybrid electric vehicle illustrating, inter alia, the condition wherein the regenerative power 162R is being supplied to the ultracapacitor bank 104 and the non self-exciting switched reluctance generator/motor 102 operating in the motor mode. Reference numeral 162M signifies charge flow from the ultracapacitor bank 104 to the DC-AC power inverter 103 and to the non self-exciting switched reluctance generator/motor 102 operating in the motor mode. Reference numeral 163M is a schematic arrow indicating rotational energy applied to the crank shaft of the internal combustion engine 101 by the switched reluctance generator/motor 102 operating in the motor mode.

(37) FIG. 1F also schematically illustrates a resistor bank 190 switchably 190S interconnected 190A with the high voltage DC bus 105. Resistor bank 190 is optionally included so as to assist with the dissipation of energy if too much is present. Additionally, resistor bank 190 assists with the control and stable operation of the hybrid electric vehicle. FIG. 1F also illustrates accessories 180 such as hydraulic systems which may contribute to the recapture of energy. Bidirectional accessory inverters 185 enable the conversion from DC to AC power and vice-versa. Electrical communication lines 180A and 185A are illustrated in FIG. 1F as well.

(38) FIG. 1G is schematic illustration 100G of a hybrid electric vehicle without an ultracapacitor bank wherein the low voltage batteries 107 are used with an engine starter for starting the internal combustion engine 101. Reference numeral 171 is a dashed line representing energy flow from the low voltage batteries 107 through the DC-DC converter 106 along the high voltage DC bus 105, through the power inverter 103 which inverts DC power to AC power for driving the non self-excited switched reluctance generator/motor 102 operating in the motor mode which mechanically drives and starts the internal combustion engine 101. Reference numeral 173 is a schematic arrow indicating energy supplied to the internal combustion engine 101 by way of a mechanical coupling for starting it.

(39) FIG. 1H is a schematic illustration of a dual compact inverter having a synergistic advantage in that two inverters are able to share a cold plate, a DC-Link capacitor bank, bus bars, a housing, a high voltage connector and wiring, and some of the low voltage electronics. Sharing makes for compact efficient packaging.

(40) The only physical I/O at the hybrid controller will be a pair of data links. All control will be exercised via these links. All sorts of control connections may be shown on data flow and control diagrams but they all exist only over the data links.

(41) Referring to FIG. 3, an electronic controller 301 as set forth therein controls the operation of the hybrid electric vehicle. FIG. 3 is an electrical schematic 300 implementing the control strategy of FIGS. 2 and 2A. FIG. 3 illustrates the non self-excited switched reluctance generator 102 as a current source. FIG. 3 also illustrates the non self-excited switched reluctance generators 110, 111, 112, 113 as current sources. Load 320 is illustrated in FIG. 3 and represents the forces required for propulsion of the vehicle and for lifting the load with the bucket. Input from the hybrid data link 310 and input from the vehicle data link 311 are shown in FIG. 3.

(42) Various algorithms may be employed in the controller 301. Further, the available energy from regeneration is continuously monitored and calculated by the controller and, therefore, the amount of energy output from the non self-excited generator 102 may be reduced. The controller 301 includes output r.sub.1 which controls the non self-excited generator 102. The controller 301 includes output r.sub.2 which controls the plurality of non self-excited AC traction generators 110, 111, 112, 113. Further, the available energy from regeneration is continuously monitored and calculated by the controller and, therefore, the amount of energy output from the non self-excited generator/motor 102 may be reduced according to the control signal output r.sub.1. In other words, the outputs of the controller, namely, output r.sub.1 and output r.sub.2, are dynamic outputs which may continuously be changed based on the status of the hybrid electric vehicle. For instance, when the vehicle is moving and carrying a raised load in a bucket, then the vehicle possesses kinetic energy by virtue of its velocity and it also has potential energy by virtue of the raised load. Room can be made for the storage of the kinetic and potential energy in the ultracapacitor wherein the controller 301 reduces the output r.sub.1 of the non self-excited switched reluctance generator/motor 102 operating in the generator mode in anticipation of the recovery of the kinetic and potential energy from the vehicle.

(43) Still referring to FIG. 3, when the vehicle has been sitting for prolonged periods of time or when the vehicle is new, the battery 107 and the DC-DC converter 106 charge the ultracapacitor 104 to enable starting of the vehicle using the non self-excited switched reluctance generator/motor 102. The low voltage batteries used are capable of storing approximately 6 times the energy that the ultracapacitor can store. Referring to FIG. 4, for instance, reference numeral 409 indicates that approximately 1.2 MJ can be stored at 800 VDC across a 1200 Farad capacitor. If a 3000 Farad capacitor is used at 800 VDC, approximately 2.8 MJ can be stored. The two preferred low voltage batteries 107 can store approximately 7 MJ at 24 VDC.

(44) FIG. 5 is a graph 500 illustrating ultracapacitor usable energy 501 versus the charge time 502 with a charge rate of 5 kW. Reference numeral 504 illustrates the charge time of 1200 Farad capacitor string. Specifically, 0.2 MJ of usable energy is stored in ultracapacitor 104 in approximately 120 seconds and this amount of energy is more than sufficient for starting the internal combustion engine when the internal combustion engine is cold. If the engine is cold, usable energy of 200 kJ is necessary to start the engine. Reference numeral 503 illustrates the charge time of a 650 Farad capacitor string, reference numeral 505 illustrates the charge time of a 1500 Farad capacitor string, reference numeral 506 illustrates the charge time of a 2000 Farad capacitor string, and reference numeral 507 illustrates the charge time of a 3000 Farad capacitor string.

(45) FIG. 6 is a graph 600 illustrating vehicle speed 601 in km/hr versus kinetic energy 602 in kJ for a 30,000 kg and a 40,000 kg vehicle. Reference numeral 603 illustrates the plot for the 30,000 kg vehicle, and reference numeral 604 illustrates the plot for the 40,000 kg vehicle. Reference numeral 605 indicates that the kinetic energy storage limit is 700 kJ which is a large portion of the total stored energy of the capacitor as viewed in FIG. 4.

(46) FIG. 7 is a graph 700 illustrating vehicle speed 702, time of operation 701 and conditions for regeneration of energy. Reference numerals 713, 714, 715, and 716 represent periods of time for regeneration of energy. Specifically, reference numeral 703 represents a four (4) second interval of time. During a portion of this period of time 703, the vehicle accelerates and attains the speed of 12 km/h. Thereafter, reference numeral 704 represents a two (2) second interval of time when the vehicle is decelerating from 12 km/h to zero km/h. During this two (2) second period of time, energy is regenerated 716 as the vehicle is slowed from 12.0 km/h to 0.0 km/h. The regeneration of energy occurs when the wheels drive the non self-excited AC traction generators/motors 110, 111, 112, and 113 in the generator mode. Other types of traction generators/motors may be used as stated hereinabove.

(47) Next, reference numeral 705 indicates zero speed for a period of three (3) seconds followed by rapid acceleration. Reference numeral is a four (4) second period of time 706. A portion of the time 706 is acceleration in the reverse direction until the vehicle attains 10 km/h. Once the vehicle attains 10 km/h in a period of one (1) second, it remains at 10 km/h for 3 seconds. Next, there is a two (2) second interval of time 707 when the vehicle is decelerating from 10 km/h to 0 km/h. During this two (2) second period of time 707, energy is regenerated 713 as the vehicle is slowed from 10 km/h to zero km/h. Next, there is a four (4) second period of time 708, two (2) seconds of which is a period of acceleration to 12 km/h. Once the vehicle attains the speed of 12 km/h it remains at 12 km/h for an additional two (2) seconds. Reference numeral 709 is a two (2) second interval of time when the vehicle is decelerating from 12 km/h to zero km/h. During this two (2) second period of time, energy is regenerated 714 as the vehicle is slowed from 12.0 km/h to 0.0 km/h.

(48) Once the vehicle comes to rest, it remains at rest for two (2) additional seconds 710. Subsequently, the vehicle accelerates rapidly in the reverse direction for 0.5 seconds until it attains a speed of 10 km/h. Reference numeral 710 represents a two (2) second interval of time when the vehicle is not moving. Reference numeral 711 is a four (4) second interval of time when the vehicle is moving in the reverse direction at a speed of 10 km/h. Subsequently, once again, in a two (2) second interval of time 712, the vehicle decelerates from 10 km/h to zero km/h and energy is recaptured/regenerated 715.

(49) FIG. 8 is a semi-log graph 800 of ultracapacitor voltage 813 versus discharge time 812 for different power levels. Reference numeral 801 represents the maximum safe voltage and reference numeral 802 is the minimum normal operating voltage at which the ultracapacitor may be operated. Reference numeral 803 illustrates the discharge time from 800 VDC at 1 kW, reference numeral 804 illustrates the discharge time from 800 VDC at 2 kW, reference numeral 805 illustrates the discharge time from 800 VDC at 4 kW, reference numeral 806 illustrates the discharge time from 800 VDC at 8 kW, reference numeral 807 illustrates the discharge time from 800 VDC at 16 kW, reference numeral 808 illustrates the discharge time from 800 VDC at 33 kW, reference numeral 808 illustrates the discharge time from 800 VDC at 65 kW, reference numeral 809 illustrates the discharge time from 800 VDC at 65 kW, reference numeral 810 illustrates the discharge time from 800 VDC at 130 kW, and, reference numeral 811 illustrates the discharge time from 800 VDC at 260 kW.

REFERENCE NUMERALS

(50) 100Aschematic illustration of a hybrid electric vehicle illustrating, inter alia, the condition wherein the capacitor is charged from the 24-volt batteries after a prolonged shut-down of the hybrid electric vehicle; 100Bschematic illustration of a hybrid electric vehicle illustrating, inter alia, the condition wherein the capacitor is sufficiently charged and supplying energy to the non self-exciting switched reluctance generator/motor to start the internal combustion engine; 100Cschematic illustration of a hybrid electric vehicle illustrating, inter alia, the condition wherein the internal combustion engine is supplying power to the non self-exciting switched reluctance generator/motor operating in the generator mode supplying power to the ultra capacitor bank, the DC-DC converter and the 24 volt batteries; 100Dschematic illustration of a hybrid electric vehicle illustrating, inter alia, the condition wherein the internal combustion engine is supplying power to the non self-exciting switched reluctance generator/motor operating in the generator mode supplying power to the ultra capacitor bank, the dual inverters which supply power to the traction motors, and to the DC-DC converter supplying the low voltage batteries; 100Eschematic illustration of a hybrid electric vehicle illustrating, inter alia, the condition wherein the regenerative power is being supplied to the ultracapacitor bank, DC-DC converter, and the low-voltage batteries; 100Fschematic illustration of a hybrid electric vehicle illustrating, inter alia, the condition wherein the regenerative power is being supplied to the ultracapacitor bank and the non self-exciting switched reluctance generator/motor operating in the motor mode; 100Gschematic illustration of a hybrid electric vehicle without an ultracapacitor bank wherein the low voltage batteries are used with an engine starter for starting the internal combustion engine; 100Hschematic illustration of a dual compact inverter having a synergistic advantage in that two inverters are able to share a cold plate, a DC-Link capacitor bank, bus bars, a housing, a high voltage connector and wiring, and some of the low voltage electronics; 101internal combustion engine; 101Aelectrical communication between switched reluctance generator/motor 102 and the internal combustion engine 101; 102non self-exciting switched reluctance generator/motor; 103inverter AC to DC in the generator mode and DC to AC in the motor mode; 103Aelectrical communication between non self-exciting generator/motor and the AC/DC inverter; 104ultracapacitor bank; 104Aelectrical communication between ultracapacitor bank 104 and high voltage DC bus; 105a high voltage DC bus; 1065 kW DC-DC converter interposed between vehicle low-voltage batteries and high voltage DC bus; 106Aelectrical communication between vehicle low-voltage batteries and DC-DC converter; 107vehicle low-voltage batteries, preferably 24 volt batteries; 108compact dual DC/AC inverter driving two AC motors/gear reducers 110, 111 for driving the front wheels of the hybrid vehicle; 109compact dual DC/AC inverter driving two AC motors/gear reducers 112, 113 for driving the rear wheels of the hybrid vehicle; 108Aelectrical communication between high voltage DC bus 105 and compact dual inverter 108; 109Aelectrical communication between high voltage DC bus 105 and compact dual inverter 109; 110, 111, 112, 113non self-exciting switched reluctance generator/motor/gear reducers for driving wheels of the hybrid vehicle; 110Aelectrical communication between compact dual DC/AC inverter 108 and traction motor 110; 111electrical communication between compact dual DC/AC inverter 108 and traction motor 111; 112Aelectrical communication between compact dual DC/AC inverter 109 and traction motor 112; 113Aelectrical communication between compact dual DC/AC inverter 109 and traction motor 113; 161charge flow from low voltage batteries 107 to the DC-DC converter 106 to the ultracapacitor bank 104; 162Gcharge flow from the non self-exciting switched reluctance generator/motor operating in the generator mode to: the DC/AC inverter 103, the ultracapacitor bank 104, the DC-DC converter 106, the low-voltage batteries 107, the compact dual inverters 108, 109, and the AC traction motors/gear reducers 110, 111, 112, and 113 for driving the wheels of the hybrid vehicle; 162Mcharge flow from the ultracapacitor bank 104 to the DC/AC inverter 103 and to the non self-exciting switched reluctance generator/motor 102 operating in the motor mode; 162Rcharge flow from the non self-exciting switched reluctance generator/motors 110, 111, 112, and 113 acting in the generator mode to the compact dual AC/DC inverters 108, 109, the high voltage DC bus, and the ultracapacitor bank 104; 163Gschematic arrow indicating rotational energy supplied by the crank shaft of the internal combustion engine 101 to the switched reluctance generator/motor operating in the generator mode; 163Mschematic arrow indicating rotational energy applied to the crank shaft of the internal combustion engine 101 by the switched reluctance generator/motor operating in the motor mode; 171dashed line representing energy flow low voltage batteries through the DC-DC converter along the high voltage DC bus, through the power inverter which inverts DC power to AC power for driving the non self-excited switched reluctance generator/motor operating in the motor mode which mechanically drives and starts the internal combustion engine; 173schematic arrow indicating energy supplied to the internal combustion engine 101; 180Aelectrical communication with accessory 180accessory 185accessory inverters 185Aelectrical communication with the accessory inverters 190resistor bank; 190Aelectrical communication line between the high voltage DC bus and the resistor bank 190; 190Aswitch interposed in the electrical communication line 190A; 200, 200Aschematic of the control strategy of the hybrid electric vehicle; 203is key in start position?; 203Ykey is in start position; 204is the internal engine running? 204Nengine is not running; 204Yengine is running; 205is there sufficient energy in the ultracapacitor bank to start the engine? 205Nif there is not sufficient energy in the ultracapacitor bank to start the engine, then proceed to step 210 and transfer energy (charge) to the ultracapacitor to charge it preferably to at least 200V DC; 205Yif there is sufficient energy in the ultracapacitor bank to start the engine, then proceed to step 203 and position the key in the start position; 207calculate recoverable energy available, Er, based on the velocity of the machine and the operational state of the machine; 207Acommunication of the calculated amount of recoverable energy to the next step 208; 208is the recoverable energy plus the energy of the ultracapacitor bank less than or equal to the maximum permissible energy stored in the ultracapacitor bank Er+Ec<Euc max? 208Nif the recoverable energy plus the energy of the ultracapacitor bank is not less than or equal to the maximum permissible energy stored in the ultracapacitor bank, in other words, if the relationship Er+Ec<Euc max is not satisfied, then proceed to the next step 216, wherein the internal combustion engine is set to idle; 208Yif the recoverable energy plus the energy of the ultracapacitor bank is less than or equal to the maximum permissible energy stored in the ultracapacitor bank, in other words the relationship Er+Ec<Euc max is satisfied, then proceed to the next step 214 and set the engine speed to the best brake specific fuel consumption and command maximum power from the non self-excited switched reluctance generator/motor 102 acting in the generator mode; 210transfer energy from the low voltage batteries to the ultracapacitor over time using the DC-DC converter 106 such that the ultracapacitor is charged to 200 V DC; 211line indicating communication of energy to the ultracapacitor bank; 214set engine to the best brake specific fuel consumption (BSFC) speed and command maximum generator power from the switched reluctance generator/motor operating in the generator mode; 215communication line to next step 235, is brake command present? 216if the recoverable energy plus the energy stored in the ultracapacitor is not less than the maximum permissible energy in the ultracapacitor, then command the internal combustion engine to idle and command the output of the switched reluctance generator/motor operating in the generator mode to zero generator current; 216Acommunication line signaling that the internal combustion engine has been commanded to idle and that the switched reluctance generator/motor operating in the generator mode is producing zero generator current; 217has wait time expired, namely, the relationship Er+Euc<Euc max has not been satisfied after the wait time? 217Ywait time has expired, proceed to step 218 and shut down the internal combustion engine; 218shutdown internal combustion engine by defueling it; 221is the brake command present? 221Nif the brake command is not present, then proceed to the next step 222, and determine if the DC Link>DC Link Min; 221Yif the brake command is present, then proceed to the next step 227, and send a negative torque command to the non self-exciting switched reluctance generator/motors 110, 111, 112, and 113 acting in the generator mode to the compact dual AC/DC inverters 108, 109; 222is DC Link>DC Link Min? 222Nif DC Link voltage is not greater than the DC link minimum voltage, then proceed to the next step 228 and send zero torque command to the switched reluctance generators/motors 110, 111, 112, 113 which drive the vehicle wheels proportional to the accelerator signal and within stability limits; 222Yif the DC Link voltage is greater than the DC link minimum voltage, then proceed to the next step 223, and the read the accelerator command from the electronic controller; 223read the accelerator command from the electronic controller; 224read the shift selector; 225is the speed of the vehicle is less than the maximum speed for the selector position? 225Nif the speed of the vehicle is not less than the maximum speed for the selector position, then proceed to the next step 228 and send zero torque command to the switched reluctance generators/motors 110, 111, 112, 113 which drive the vehicle wheels; 225Yif the speed of the vehicle is less than the maximum speed for the selector position, proceed to the next step 226, is the machine in forward gear? 226is the vehicle in forward gear? 226Nif the speed of the vehicle is not in the forward position, then proceed to the next step and send a negative torque command to the switched reluctance generators/motors 110, 111, 112, 113 which drive the vehicle wheels proportional to the accelerator signal and within stability limits to drive the vehicle in backward direction; 226Yif the vehicle is in forward gear, proceed to the next step 229 and send the positive torque command to the switched reluctance generators/motors 110, 111, 112, 113 which drive the vehicle wheels proportional to the accelerator signal and within stability limits to drive the vehicle in the forward direction; 227send negative torque command to the switched reluctance generators/motors 110, 111, 112, 113 which drive the vehicle wheels proportional to the brake command 225Y and within stability limits; 228send zero torque command to the switched reluctance generators/motors 110, 111, 112, 113 which drive the vehicle wheels; 229send a positive torque command to the switched reluctance generators/motors 110, 111, 112, 113 which drive the vehicle wheels; 230send a negative torque command to the switched reluctance generators/motors 110, 111, 112, 113 which drive the vehicle wheels proportional to the accelerator signal and within stability limits; 300electrical schematic implementing the control strategy of FIGS. 2 and 2A; 301controller 310input from hybrid data link 311input from vehicle data link 400graph illustrating the ultracapacitor voltage versus the ultracapacitor total stored energy; 401ultracapacitor voltage; 402ultracapacitor total stored energy (MJ); 403650 Farad capacitor string; 4041200 Farad capacitor string; 4051500 Farad capacitor string; 4062000 Farad capacitor string; 4073000 Farad capacitor string; 408500 volt abscissa mark; 409800 volt abscissa mark; 4101.3 MJ ordinate mark; 500graph illustrating ultracapacitor usable energy versus the charge time; 501usable energy bank; 502charge time at 5 KW; 503650 Farad capacitor string; 5041200 Farad capacitor string; 5051500 Farad capacitor string; 5062000 Farad capacitor string; 5073000 Farad capacitor string; 600graph illustrating vehicle speed versus kinetic energy for a 30,000 kg and a 40,000 kg vehicle; 601vehicle speed in km/h; 602kinetic energy in kJ; 60330,000 kg vehicle without a load; 60440,000 kg vehicle including the load; 605energy storage limit, 800V DC; 700graph illustrating vehicle speed, time and conditions for regeneration of energy; 701time; 702vehicle speed km/h; 7034 second interval of time where the vehicle accelerates and attains 12 km/h; 7042 second interval of time when the vehicle is decelerating from 12 km/h to zero km/h; 7052 second interval of time; 7064 second interval of time when the vehicle is accelerating in the reverse direction; 7072 second interval of time when the vehicle is decelerating from 10 km/h to zero km/h; 7084 second interval of time where the vehicle accelerates and attains 12 km/h; 7092 second interval of time when the vehicle is decelerating from 12 km/h to zero km/h; 7102 second interval of time; 7114 second interval of time when the vehicle is accelerating in the reverse direction; 7122 second interval of time when the vehicle is decelerating from 10 km/h to zero km/h; 713, 714, 715, 716shaded area representing regeneration of energy; 800semi-log graph of ultracapacitor voltage versus time for different power levels; 801minimum normal operating voltage; 802maximum safe voltage; 8031 kW; 8042 kW; 8054 kW; 8068 kW; 80716 kW; 80833 kW; 80865 kW; 809130 kW; 810130 kW; 811260 kW; 812time in minutes; 813voltage, DC; control of hybrid vehicle;

(51) Those skilled in the art will recognize that the invention has been set forth by way of example only and that changes may be made to the invention without departing from the spirit and scope of the appended claims.