WO2011083369A1

WO2011083369A1 - Gas-turbines, controllers, hybrid gas-turbine electric vehicles and methods of operation thereof

Info

Publication number: WO2011083369A1
Application number: PCT/IB2010/050061
Authority: WO
Inventors: Arieh Meitav; Irad Kuhnreich; Dror Ben David
Original assignee: Etv Motors Ltd.
Priority date: 2010-01-08
Filing date: 2010-01-08
Publication date: 2011-07-14

Abstract

Methods for operating a hybrid gas-turbine electric vehicle are disclosed, which in some embodiments include suspending the supplying of fuel to the gas-turbine combustor during gas-turbine operation. Also disclosed are controllers suitable for use with gas-turbines, gas-turbines and hybrid gas-turbine electric vehicles that in some embodiments are useful for implementing some embodiments of the disclosed method.

Description

GAS-TURBINES, CONTROLLERS, HYBRID GAS-TURBINE ELECTRIC VEHICLES AND METHODS OF OPERATION THEREOF

FIELD AND BACKGROUND OF THE INVENTION

The present invention, in some embodiments, relates to the field of motor vehicles, and more particularly, but not exclusively, to hybrid gas-turbine electric vehicles, gas- turbines, controllers suitable for use with gas-turbines and methods of operating hybrid gas- turbine electric vehicles.

Wheeled motor vehicles are an inseparable part of a modern industrial society, providing cheap, simple and efficient transport of people and goods.

The ubiquity of motor vehicles is in a large part a result of the existence of the internal combustion engine (ICE), primarily Otto-cycle and Diesel-cycle engines fueled by cheap and readily available fossil fuel. ICEs have a reasonable power to weight ratio and provide a wide range of power on demand. However, ICEs are relatively inefficient and continuously produce harmful emissions even when idling.

An alternative to ICE-powered vehicles is all-electric vehicles. All-electric vehicles have one or more electric drive motors powered with electricity stored in on-board battery packs. Electric motors produce no harmful emissions during operation. The battery packs are charged from the electric grid while the vehicle is parked with electrical energy produced in a remote central electric power plant. All-electric vehicles have a limited range, especially when driving at high speeds or with heavy loads.

Hybrid electric vehicles overcome some of the disadvantages of ICE-powered vehicles and of all-electric vehicles. Such vehicles include a fuel-burning engine powering a generator, one or more electric drive motors, and battery packs to store electrical energy. Additionally, hybrid electric vehicles generally include a power management unit, that incorporates power electronics components such as rectifiers, inverters, converters and battery chargers, for accepting, transferring and directing electric power from power generating components like the generator to power-using components like the drive motors, as well as controlling the charging of the battery packs/drawing of electric power from the battery packs.

Hybrid electric vehicles produce fewer emissions and are more fuel-efficient than ICE vehicles and are not limited in range like all-electric vehicles. There are different types of hybrid vehicles. In parallel hybrid ICE electric vehicles, the ICE primarily drives the vehicle while the electric drive motors provide extra driving power when needed, allowing the ICE to be smaller than otherwise.

In serial hybrid ICE electric vehicles, electric drive motors primarily drive the vehicle while an ICE acts as an on-board charger to generate electrical energy to store in a battery pack and/or to directly power the drive motors through the power management unit. In such vehicles, the battery packs may be optionally charged with electrical energy from the power grid while the vehicle is parked.

Often, hybrid electric vehicles are provided with regenerative braking units that brake the vehicle by converting kinetic energy to electrical energy that, through the power management unit, is subsequently stored in the battery packs. The battery pack stores this otherwise wasted power to be used by the electrical motors to drive the vehicle when extra power is needed, consequently reducing vehicular fuel use and increasing vehicular range.

An alternative to a hybrid ICE electric vehicle is a hybrid gas-turbine electric vehicle, where a gas-turbine is used instead of an ICE.

In Figure 1A a typical Brayton cycle gas-turbine 10 and in Figure IB a typical inverse Brayton cycle gas-turbine 11 are schematically depicted, both comprising a combustor 12, a turbine 14 and a compressor 16, together mounted on a common rotatable shaft 18 constituting a spool, an air inlet 20 and an exhaust duct 22. One end of shaft 18 constitutes the rotor of generator 24. Gas-turbine 10 or 11 and a generator 24 together with other components such as fuel-supply unit 26 and gas-turbine controller 28 constitute a power generation unit 30.

In typical Brayton-cycle operation schematically depicted in Figure 1A, air from the surroundings is drawn into air inlet 20 and forced by compressor 16 into combustor 12. In combustor 12, the air is mixed with fuel and the mixture combusted. The hot exhaust gases resulting from the combustion are directed into turbine 14. The hot exhaust gases expand through and rotate turbine 14, consequently rotating shaft 18 and compressor 16 before exiting gas -turbine 10 through exhaust duct 22 to be released to the surroundings.

In typical inverse Brayton-cycle operation schematically depicted in Figure IB, air from the surroundings is drawn into combustor 12 through air inlet 20. In combustor 12, the air is mixed with fuel and the mixture combusted. The hot exhaust gases resulting from the combustion are directed into turbine 14. The hot exhaust gases expand through and rotate turbine 14, consequently rotating shaft 18 and compressor 16. The hot exhaust gases are then forced by compressor 16 through exhaust duct 22 to be released into the surroundings. In both the Brayton cycle and the inverse Brayton cycle, the rotation of shaft 18 by exhaust gases expanding through turbine 14 causes generator 24 to generate electric power from the mechanical power of the rotation of turbine 14.

Gas-turbines such as 10 or 11 typically include a gas-turbine controller 28 that monitors and controls the gas-turbine, including by regulating the amount of fuel supplied to combustor 12 by fuel- supply unit 26.

To increase thermal efficiency, gas-turbines such as 10 or 11 typically include a heat- exchanger 32, such as a recuperator or regenerator, that recovers heat from the hot exhaust gases (passing through a hot-stream conduit 34) to preheat air (passing through a cold-stream conduit 36) prior to entering combustor 12.

In Figure 2, a typical hybrid gas-turbine electic vehicle 38 is schematically depicted, comprising a power generation unit 30 including Brayton-cycle gas-turbine 10, generator 24, fuel- supply unit 26 and gas-turbine controller 28, a power management unit 40, an operator interface 42, four electric drive motors 44 each functionally associated with a vehicle wheel, a chargeable power storage unit 46 including a chargeable battery pack 48, a capacitor 50 and a charge-state indicator 52, a regenerative braking unit 54 including four assemblies, each assembly functionally associated with a vehicle wheel and a grid charging unit 56.

During operation, power generation unit 30 supplies power management unit 40 with electrical power generated by generator 24 from mechanical power produced by gas-turbine 10. Based on operator instructions received through operator interface 42, power management unit 40 directs a required amount of power to drive motors 44 and auxiliary loads such as an air conditioner (not depicted).

When power generation unit 30 supplies insufficient power (e.g. , required for sudden acceleration of vehicle 38), power management unit 40 draws the extra required power from power storage unit 46.

When power generation unit 30 supplies more power than needed (e.g. , vehicle 38 stops), power management unit 40 stores the excess power in power storage unit 46.

When vehicle 38 brakes, regenerative braking unit 54 is optionally activated, converting vehicular kinetic energy to electric power and directing the electrical power to power management unit 40 for immediate use (e.g. , powering auxiliary loads) or storage in power storage unit 46.

If power storage unit 46 is storing sufficient power (e.g. , was previously charged with power supplied by power generation unit 30, regenerative braking unit 54 and/or grid charging unit 56) as indicated by charge-state indicator 52, power generation unit 30 is optionally not activated. Instead, power management unit 40 draws all the required power from power storage unit 46.

Gas-turbines are known to be lightweight, reliable, and for efficiently producing mechanical power from chemical energy in a combustible fuel. However, gas-turbines are not well known for use with ground vehicles such as cars, trucks and buses for a number of reasons as discussed in US 6,526,757 and by Capata R and Sciubba E in Int. J. Energy Res. 2006, 30, 671-684.

A first reason is that a given gas-turbine has a designed power output, that is to say is designed to produce a specific power output at highest efficiency at a corresponding designed optimal rotation speed. Generation of power that is greater or lesser than the designed power output is significantly less efficient.

A second reason is that the power requirements for ground vehicles are low compared to the power gas-turbines efficiently produce.

A third reason is "turbine lag": it takes a noticeably long time for a given gas-turbine to speed-up and stabilize to produce more power and to slow-down and stabilize to produce less power.

A fourth reason is that the lifetime of gas-turbines is severely limited by startup/shutdown events. Unlike an ICE, it is not practical to shut down a gas-turbine when idling.

Vehicles such as automobiles, trucks and buses have highly variable power demands, requiring more power for rapid acceleration or climbing hills, requiring less power when cruising and virtually no power when stopped. Thus, implementing such vehicles as hybrid gas-turbine electric vehicles is not necessarily practical because, as explained above, gas- turbines are inherently not suitable for efficiently providing varying amounts of power

Further, to increase fuel efficiency and to ensure adequate performance when a hybrid gas-turbine electric vehicle has high power requirements, the gas-turbine must be relatively powerful at the designed power output. As a result, the gas-turbine generates excess power during usual operation when the vehicle requires less power. Excess power can be stored in a power storage unit, but the power storage unit is eventually filled to capacity. The gas-turbine can be operated to produce less than the designed power output, but the loss of efficiency renders such operation uneconomical. Theoretically, a gas-turbine can be shutdown (e.g., when the power storage unit is full) and restarted when needed, but performance will suffer due to turbine-lag and startup/shutup events are relatively fuel inefficient, polluting and as noted above, limit the lifetime of the gas-turbine. The excess power problem is is aggravated with the use of regenerative braking, especially in hilly terrain or along bus routes, where high power requirements (climbing a hill, accelerating) alternate with power-generating braking events (descending from a hill, stopping at a station). As a result, a power storage unit is quickly filled to capacity so that excess energy cannot be stored and is wasted.

As a result, despite a great theoretical potential, hybrid gas-turbine electric vehicles remain effectively unknown due to a low actual fuel efficiency and high operating costs.

SUMMARY OF THE INVENTION

Some embodiments of the invention relate to methods for operating hybrid gas- turbine electric vehicle, which in some embodiments overcome some of the challenges of known methods of operating hybrid gas-turbine electric vehicles.

In some embodiments, supplying of fuel to the combustor of a gas-turbine is suspended during operation of the gas-turbine and resumed prior to complete stopping of rotation of the gas-turbine compressor. In some such embodiments, power generation, fuel usage and/or emissions are temporarily reduced without shutting the gas-turbine down. As a result, in some such embodiments, less excess power is generated, leading to improved fuel consumption and/or lowered emissions.

Some embodiments of the invention relate to gas-turbines, controllers for gas-turbines and hybrid gas-turbine electric vehicles that in some embodiments are useful for implementing methods of the invention.

According to an aspect of some embodiments of the invention, there is provided a method of operating a hybrid gas-turbine electric vehicle including: at least one gas-turbine with a combustor, a compressor and a turbine, the gas-turbine functionally associated with at least one generator; the method comprising:

supplying fuel to the combustor of the gas-turbine to maintain fuel combustion in the combustor;

(intentionally) suspending supplying of fuel to the combustor, thereby stopping fuel combustion in the combustor;

allowing the compressor of the gas-turbine to rotate for a period of time during which supplying of fuel is suspended; and

prior to complete stopping of rotation of the compressor, resuming supplying fuel to the combustor and resuming fuel combustion in the combustor. According to an aspect of some embodiments of the invention, there is also provided a controller suitable for use with a gas-turbine, comprising:

a) a processor unit, configured to: based on fuel- suspension rules, automatically suspend for a period of time the supplying of fuel to a combustor of a gas-turbine with which the controller is functionally associated; based on fuel-resumption rules, automatically resume the supplying of fuel to the combustor while a compressor of the gas-turbine is still rotating; and

b) an input for accepting a current speed of rotation of the compressor of the gas- turbine.

According to an aspect of some embodiments of the invention, there is also provided a hybrid gas-turbine electric vehicle, comprising: a) a power management unit; b) at least one electric drive motor for driving the vehicle using electric power provided by the power management unit; c) at least one gas-turbine including a turbine, a combustor, a compressor and a fuel- supply unit, functionally associated with at least one generator to generate electric power from mechanical power produced by the gas-turbine, and to provide the generated power to the power management unit; d) a chargeable power storage unit for storing electric power received from the power management unit and for releasing stored power to the power management unit; and e) a controller configured to (automatically) suspend the supplying of fuel to the combustor by the fuel-supply unit when the compressor is rotating. In some embodiments, the controller is configured to automatically suspend the supplying of fuel. In some embodiments, the controller is further configured to automatically resume the supplying of fuel by the fuel-supply unit to the combustor while the compressor is still rotating. According to an aspect of some embodiments of the invention, there is also provided a gas-turbine suitable for use in a gas-turbine hybrid electric vehicle, configured for implementing the method of operating a gas-turbine as described herein. In some embodiments, a gas-turbine for implementing the teachings herein is a gas-turbine including one or more components described herein for implementing some embodiments of the invention such as one or more valves and/or a compressor-rotating motor.

In some embodiments, a gas-turbine for implementing the teachings herein is a gas- turbine comprising a controller for implementing some embodiments of the method described herein as a gas-turbine controller. Thus, in some embodiments of the invention, there is also provided a gas-turbine suitable for use in a gas-turbine hybrid electric vehicle, comprising: a) a turbine; b) a combustor configured for combusting fuel with air and directing resulting exhaust to expand through the turbine; c) a compressor for directing air from the surroundings to the combustor; e) a fuel- supply unit configured to regulate the supplying of fuel to the combustor; and f) a gas-turbine controller configured to suspend the supplying of fuel to the combustor by the fuel-supply unit while the compressor is rotating, in some embodiments substantially as described herein. In some embodiments, the gas-turbine controller is configured to automatically suspend the supplying of fuel. In some embodiments, the gas-turbine controller is further configured to automatically resume the supplying of fuel by the fuel-supply unit to the combustor while the compressor is still rotating.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In case of conflict, the patent specification, including definitions, will control.

Some embodiments of the methods described herein involve performing or completing some tasks manually, automatically, or a combination thereof. Some embodiments are implemented with the use of components (such as a controller suitable for use with a gas- turbine, a gas-turbine controller, or a power management unit) that comprise hardware, software, firmware or combinations thereof. In some embodiments, some components are dedicated or custom components such as circuits, integrated circuits or software. For example, in some embodiments, some of the embodiment is implemented as a plurality of software instructions executed by a data processor, for example which is part of a computer or like component. In some embodiments, the data processor or computer comprises volatile memory for storing instructions and/or data and/or a non-volatile storage, for example, a magnetic hard-disk and/or solid-state electronic flash memory data storage device, for storing instructions and/or data. In some embodiments, implementation includes a network connection. In some embodiments, implementation includes a user interface, generally comprising one or more of input devices (e.g. , allowing input of commands and/or parameters) and output devices (e.g. , allowing reporting parameters of operation and results. In some embodiments, implementation includes communication of instructions to an additional device to perform an action.

As used herein, the terms "comprising", "including", "having" and grammatical variants thereof are to be taken as specifying the stated features, integers, steps or components but do not preclude the addition of one or more additional features, integers, steps, components or groups thereof. These terms encompass the terms "consisting of" and "consisting essentially of". BRIEF DESCRIPTION OF THE FIGURES

Some embodiments of the invention are herein described, by way of example only, with reference to the accompanying figures. The description, together with the figures, makes apparent how embodiments of the invention may be practiced to a person having ordinary skill in the art. The figures are for the purpose of illustrative discussion of embodiments of the invention and no attempt is made to show structural details of an embodiment in more detail than is necessary for a fundamental understanding of the invention. For the sake of clarity, some objects schematically depicted in the figures are not to scale.

In the Figures:

FIGS. 1A and IB (prior art) are schematic depictions of a Brayton cycle gas-turbine (Figure 1A) and an inverse-Brayton cycle gas-turbine (Figure IB);

FIG. 2 (prior art) is a schematic depiction of a hybrid gas-turbine electric vehicle;

FIGS. 3 A, 3B and 3C are schematic depictions of an embodiment of a hybrid gas- turbine electric vehicle (Figure 3A), a corresponding power generation unit (Figure 3B) and a corresponding gas-turbine controller (Figure 3C);

FIGS. 4A, 4B and 4C are schematic depictions of an embodiment of a hybrid gas- turbine electric vehicle (Figure 4A), a corresponding power generation unit including a gas- turbine/generator clutch (Figure 4B) and a corresponding gas-turbine controller (Figure 4C);

FIGS. 5 A, 5B and 5C are schematic depictions of an embodiment of a hybrid gas- turbine electric vehicle (Figure 5A), a corresponding power generation unit including a compressor outlet valve (Figure 5B) and a corresponding gas-turbine controller (Figure 5C);

FIGS. 6A, 6B and 6C are schematic depictions of an embodiment of a hybrid gas- turbine electric vehicle (Figure 6A), a corresponding power generation unit including a compressor/turbine clutch and compressor rotating motor (Figure 6B) and a corresponding gas-turbine controller (Figure 6C);

FIGS. 7 A, 7B and 7C are schematic depictions of an embodiment of a hybrid gas- turbine electric vehicle (Figure 7A), a corresponding power generation unit including a compressor/turbine clutch and compressor inlet valve (Figure 7B) and a corresponding gas- turbine controller (Figure 7C); FIGS. 8A-8D are schematic depictions of an embodiment of a power generation unit including a multipower gas-turbine; and

FIGS. 9A and 9B are schematic depictions of a Brayton cycle gas-turbine (Figure 9A) and an inverse-Brayton cycle gas-turbine (Figure 9B) including valves suitable for implementing embodiments of the invention.

DESCRIPTION OF SOME EMBODIMENTS OF THE INVENTION

Aspects of the invention relate to hybrid gas-turbine electric vehicles and methods of operating hybrid gas-turbine electric vehicles. Some embodiments of the invention relate to methods for operating a hybrid gas-turbine electric vehicle, which in some embodiments include suspending the supplying of fuel to the combustor of the gas-turbine during operation thereof. Some embodiments of the invention relate to controllers suitable for gas-turbines, gas-turbines and hybrid gas-turbine electric vehicles that in some embodiments are useful for implementing the methods of operating a hybrid gas-turbine electric vehicle.

The principles, uses and implementations of the teachings of the invention may be better understood with reference to the accompanying description and figures. Upon perusal of the description and figures present herein, one skilled in the art is able to implement the teachings of the invention without undue effort or experimentation. In the figures, like reference numerals refer to like parts throughout.- Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details set forth herein. The invention can be implemented with other embodiments and can be practiced or carried out in various ways. It is also understood that the phraseology and terminology employed herein is for descriptive purpose and should not be regarded as limiting.

Method of operating a hybrid gas-turbine electric vehicle

According to an aspect of some embodiments of the invention, there is provided a method of operating a hybrid gas-turbine electric vehicle including: at least one gas-turbine with a combustor, a compressor and a turbine, the gas-turbine functionally associated with at least one generator (to generate electrical power from mechanical power produced by the gas- turbine), the method comprising:

supplying fuel to the combustor of the gas-turbine to maintain fuel combustion in the combustor; (intentionally) suspending supplying of fuel to the combustor, thereby stopping fuel combustion in the combustor;

prior to complete stopping of rotation of the compressor, resuming supplying fuel to the combustor and resuming fuel combustion in the combustor.

Generally, a vehicle also includes at least one electric drive motor for driving the vehicle, a chargeable power storage unit for storing and releasing electric power, and a power management unit to accept electric power from power sources and distribute electric power to power users, substantially as discussed in the introduction.

As long as fuel is supplied to the combustor, the gas-turbine produces mechanical power and the generator generates electric power to be used to power the vehicle, substantially in the manner known in the art.

According to some embodiments of the method, during operation of the gas-turbine the supplying of fuel to the combustor is intentionally suspended for a period of time. Fuel combustion in the combustor stops and consequently, electric power generation is substantially stopped during the period of time. The compressor (and in some embodiments, other gas-turbine components) continues rotating.

As noted in the introduction, it is desirable to operate a gas-turbine as much as possible at the highest possible efficiency. Typical gas-turbines have a designed power output that is much higher than required for terrestrial vehicles. Additionally, terrestrial vehicles require a very broad range of powers under normal operating conditions. Startup/shutdown events are undesirable as polluting, inefficient, reduce gas-turbine lifetime and are accompanied by turbine-lag.

In some embodiments, the method described herein overcomes some of the challenges of operating a hybrid gas-turbine electric vehicle. When too much electrical power is generated or available for vehicular operation, the supplying of fuel to the gas-turbine combustor is suspended so that power generation and fuel use are also suspended without actually shutting the gas-turbine down. As a result, some embodiments allow operation of a gas-turbine for a greater proportion of time closer to the designed power output, leading to fuel-savings In some embodiments, by resuming the supplying of fuel while the compressor is still rotating, turbine lag is reduced and in some embodiments even substantially eliminated. In some embodiments when the vehicle brakes, power generation by the gas- turbine is optionally suspended by suspending the supplying of fuel and power generated by a regenerative braking unit is stored in a power storage unit and subsequently used for vehicular operation, in some embodiments allowing greater use of power recovered by a regenerative braking unit.

The supplying of fuel is suspended for any suitable reason. Generally, suspension of supplying of fuel is because the vehicle has too much electrical power available or is expected to have too much electrical power available. Instead of combusting fuel and producing emissions when not needed, the method allows the supplying of fuel to be suspended when sufficient power is available from other sources, increasing fuel efficiency and reducing emissions. For example, in some embodiments, supplying of fuel is suspended when sufficient power is produced by a regenerative braking unit. For example, in some embodiments, supplying of fuel is suspended when a power storage unit is filled to a sufficient extent, for example to an extent where excess power generated by the generator or by a regenerative braking unit cannot be stored in the power storage unit.

Prior to complete stopping of rotation of the compressor, the supplying of fuel and fuel combustion in the combustor is resumed and consequently, electric power generation is resumed. As the compressor has not completely stopped rotating, in some embodiments resumption of fuel combustion is not as inefficient and/or damaging as a usual gas-turbine startup event. In some embodiments, turbine lag is less significant than turbine lag of a usual gas-turbine startup event.

As is known in the art, ignition of a gas-turbine is a complex task that requires that the compressor rotate at a rate sufficient to provide a sufficient amount of air that is combined with a specific amount of fuel in the combustor, depending on the combustor temperature. As a result, for any given combustor temperature a given gas-turbine has an ignition rotation window, a range of compressor rotation speeds at which the gas-turbine can be ignited. Generally, resuming supplying fuel to the combustor according to the teachings herein is when the rotational speed of the compressor is within the ignition rotation window. In some embodiments, resuming supplying fuel to the combustor is when the rotational speed of the compressor is not less than about 30%, not less than about 40%, not less than about 50%, not less than about 60% and even not less than about 70% of the designed optimal rotational speed of the gas-turbine.

e.g.Jn some embodiments, the method comprises, concurrently with the resumption of the supplying of fuel to the combustor, igniting fuel, thereby resuming fuel combustion in the combustor. Igniting of the fuel is in the usual way, for example with the use of an ignitor that generates a spark or flame in the combustor. In some embodiments, during the period of time between the suspending and resuming of the supplying of fuel, the compressor rotates from inertia.

In some embodiments, the method further comprises during at least part of the period of time during which supplying of fuel is suspended, rotating the compressor. In such embodiments, during at least part of the period of time, the compressor is actively rotated, that is to say, work is performed to rotate the compressor. Some embodiments including rotating the compressor have advantages when compared to embodiments where a compressor rotates by inertia. In some embodiments, excess power (e.g. , generated by a regenerative braking unit or stored in a power storage unit) which might otherwise be wasted is used for rotating the compressor. As a result, in some such embodiments, the maximal period of time during which fuel supplying is suspended is increased. In some such embodiments, active rotating of the compressor allows the rotational speed of the compressor to be substantially higher when fuel supplying is resumed, in some embodiments allowing quicker gas-turbine stabilization and/or reduced turbine lag.

In some embodiments, the vehicle includes a compressor-rotating motor functionally associated with the compressor, and rotating of the compressor comprises activating the compressor-rotating motor. In some such embodiments, the compress-rotating motor is an electric motor. In some such embodiments, the compress-rotating motor is substantially the generator operated as a motor. In some such embodiments, the compress-rotating motor is a motor other than the generator.

In some embodiments, the vehicle includes at least one chargeable power storage unit (e.g. , a battery, a capacitor, both a battery and a capacitor) for storing and releasing electric power, wherein the rotating of the compressor comprises using electric power released from the chargeable power storage unit.

In some embodiments, the vehicle includes a regenerative braking unit configured for generating electric power from vehicular kinetic energy, wherein the rotating of the compressor comprises using power generated by the regenerative braking unit.

In some embodiments, the rotating of the compressor is substantially continuous. In some such embodiments, the rotating of the compressor is intermittent.

In some embodiments, the rotating of the compressor maintains the compressor at a rotational speed of not less than about 30%, not less than about 40%, not less than about 50%, not less than about 60% and even not less than about 70% of the designed optimal rotational speed of the gas-turbine. In some such embodiments, the rotating of the compressor maintains the compressor at a rotational speed within the ignition rotation window. In some embodiments, the method further comprises during at least part of the period of time during which supplying of fuel is suspended, substantially reducing load on the compressor. Some such embodiments allow the compressor to rotate at a higher speed and/or for a longer time. Some such embodiments allow rotation of the compressor with less work.

In some embodiments, the method further comprises: during at least part of the period of time during which supplying of fuel is suspended, reducing (in some embodiments, even to the extent of substantially blocking) air flow through the turbine of the gas-turbine, that in some embodiments substantially reduces load on the compressor.

In some embodiments wherein the gas-turbine is operating according to a Brayton cycle, the method further comprises: during at least part of the period of time during which supplying of fuel is suspended, directing at least some, in some embodiments substantially all, air from an outlet of the compressor of the gas-turbine to the surroundings, that in some embodiments substantially reduces load on the compressor.

In some embodiments wherein the gas-turbine is operating according to an inverse Brayton cycle, the method further comprises: during at least part of the period of time during which supplying of fuel is suspended, directing at least some (in some embodiments, substantially all) air flow into an inlet of the compressor without passing through the turbine, that in some embodiments substantially reduces load on the compressor.

In some embodiments, the method further comprises: during at least part of the period of time during which supplying of fuel is suspended, decoupling the turbine from the compressor, for example with the use of a clutch, that in some embodiments substantially reduces load on the compressor. Generally, in such embodiments the turbine and the compressor are recoupled when fuel combustion is resumed.

In some embodiments, the vehicle includes a heat-exchanger (e.g. , a regenerator or a recuperator) functionally associated with the gas-turbine, and the method further comprises: during at least part of the period of time during which supplying of fuel is suspended, reducing (in some embodiments, even to the extent of substantially blocking) cold-stream flow through the heat-exchanger, that in some embodiments substantially reduces load on the compressor.

In some embodiments, the vehicle includes a heat-exchanger functionally associated with the gas-turbine, and the method further comprises: during at least part of the period of time during which supplying of fuel is suspended, reducing (in some embodiments, even to the extent of substantially blocking) hot-stream flow through the heat-exchanger, that in some embodiments substantially reduces load on the compressor. In some embodiments, reducing or even substantially blocking hot-stream and/or cold- stream flow through a heat-exchanger when the supplying of fuel is suspended substantially reduces the rate of cooling of the heat-exchanger, saving energy and increasing gas-turbine efficiency when the supplying of fuel is resumed.

In some embodiments, the method further comprises: during at least part of the period of time during which supplying of fuel is suspended, reducing (in some embodiments to the extent of substantially blocking) air flow through the combustor, that in some embodiments substantially reduces the rate of cooling of the combustor, saving energy and increasing gas- turbine efficiency when the supplying of fuel is resumed.

Any suitable vehicle may be used in implementing the method described herein. In some embodiments, the vehicle is a wheeled vehicle, for instance a vehicle selected from the group of automobiles, minibuses (having a capacity of up to ten seated passengers and a operator), buses, light trucks (up to about 3500 kilogram gross vehicular mass, including pickups, SUVs, vans and minivans) and heavy trucks (from about 3500 kilogram gross vehicular mass). In some embodiments, vehicle of the invention is a track-riding vehicle (e.g., a train or tram).

A vehicle including one or more suitable gas-turbines may be used in implementing the method described herein. In some embodiments, the gas-turbine is configured for operation according to a Brayton cycle. In some embodiments, the gas-turbine is configured for operation according to an inverse Brayton cycle. In some embodiments, the gas-turbine is a multipower gas-turbine configured for operation according to both a Brayton-cycle and an inverse Brayton cycle, see for example, US 6,526,757.

Controller suitable for use with a gas-turbine

In some embodiments, the method of operating a hybrid gas-turbine vehicle is implemented with a vehicle provided with a controller configured for implementing some embodiments of the method.

A controller used for implementing the teachings herein may be any suitable configured or configurable controller, as known in the art of gas-turbines and gas-turbine powered vehicles (terrestrial, naval and aeronautical). Such controllers, generally include input channels for accepting instructions and to accept information about a functionally associated gas-turbine and the environment from sensors, as well as processors, memory components and the like, as well as instructions and data structures (e.g., as hardware or software). Suitable controllers are available from various suppliers, for example Petrotech, Inc., St. Rose, Louisiana, USA. In some embodiments, the controller is a controller as described herein.

According to an aspect of some embodiments of the invention, there is provided a controller suitable for use with a gas-turbine, comprising:

a) a processor unit, configured to:

based on fuel- suspension rules, automatically suspend for a period of time the supplying of fuel to a combustor of a gas-turbine with which the controller is functionally associated;

based on fuel-resumption rules, automatically resume the supplying of fuel to the combustor while a compressor of the gas-turbine is still rotating; and b) an input for accepting a current speed of rotation of the compressor of the gas- turbine.

In some embodiments, such a controller, or some functions and/or parts thereof are a part of a gas-turbine controller. In some embodiments, such a controller, or some functions and/or parts thereof are an independent unit. In some embodiments, such a controller, or some functions and/or parts thereof are part of a different component of a vehicle. For example, in some embodiments, such a controller, or some functions and/or parts thereof are part of a power management unit. In some embodiments, functions and/or parts of such a control are a part of two or more vehicular components, for example a gas-turbine controller and a power management unit.

In some embodiments, the fuel-resumption rules include possible resumption of the supplying of fuel to the combustor when a current speed of rotation of the compressor of the gas-turbine approaches a lower limit. In some embodiments, the lower limit is not less than about 30%, not less than about 40%, not less than about 50%, not less than about 60% and even not less than about 70% of a designed optimal rotational speed of the compressor of the gas-turbine.

In some embodiments, the fuel-resumption rules include possible resumption of the supplying of fuel to the combustor when a current speed of rotation of the compressor of the gas-turbine is within the ignition rotation window of the compressor. It is important to note that the ignition rotation window of a given gas-turbine may be dependent on various factors such as combustor temperature, heat-exchanger temperature, ambient temperature and ambient pressure. In some embodiments, an ignition rotation window is determined, in the usual way, with the help of one or more sensors that measure the relevant factors. In some embodiments, the controller is configured to activate an ignitor to ignite fuel concurrently with the resumption of the fuel- supplying to resume combustion in a combustor of the gas-turbine

In some embodiments, the fuel- suspension rules include possible suspension of the supplying of fuel when a current state of charge of at least one storage component of a power storage unit is above a minimum value.

In some embodiments, the fuel-resumption rules include possible resumption of the supplying of fuel when a current state of charge of at least one storage component of a power storage unit is below a minimum value.

In some embodiments, the controller further comprises an input for accepting a current state of charge of at least one storage component of a power storage unit, e.g. of a battery pack, or a capacitor, of both a battery and a capacitor.

In some embodiments, the fuel- suspension rules include possible suspension of the supplying of fuel when a regenerative braking unit generates more than a minimum amount of power.

In some embodiments, the fuel-resumption rules include possible resumption of the supplying of fuel when a regenerative braking unit generates less than a minimum amount of power.

In some embodiments, the fuel controller further comprises an input for accepting a power status of a regenerative braking unit.

In some embodiments, the fuel- suspension rules include possible suspension of the supplying of fuel when a vehicular drive motor requires less than minimum amount of power.

In some embodiments, the fuel-resumption rules include possible resumption of the supplying of fuel when a vehicular drive motor requires more than a minimum amount of power.

In some embodiments, the controller further comprises an input for accepting a current power requirement of at least one vehicular drive motor.

In some embodiments, the controller is configured to activate an additional vehicular component to reduce a load on a compressor of the gas-turbine during at least part of the period of time during which supplying of fuel is suspended.

In some embodiments, the controller is configured to set a turbine inlet valve to reduce (in some embodiments, to the extent of substantially entirely blocking) air flow into a turbine of the gas-turbine during at least part of the time when the fuel supplying is suspended. In some embodiments, the controller is configured to set a compressor outlet valve to direct at least some (in some embodiments, substantially all) air flow from a compressor of the gas-turbine to the surroundings during at least part of the time when the fuel supplying is suspended.

In some embodiments, the controller is configured to set a compressor inlet valve to direct at least some (in some embodiments, substantially all) air flow into an inlet of a compressor of a gas-turbine without passing through a turbine of the gas-turbine during at least part of the time when the fuel supplying is suspended.

In some embodiments, the controller is configured to activate a turbine/compressor clutch to decouple a turbine of a gas-turbine from a compressor of a gas-turbine during at least part of the time when the fuel supplying is suspended.

In some embodiments, the controller is configured to activate a gas-turbine/generator clutch to decouple a gas-turbine from a generator of the vehicle during at least part of the time when the fuel supplying is suspended.

In some embodiments, a controller is configured to set a heat-exchanger cold- stream valve to reduce (in some embodiments, to the extent of substantially entirely blocking) air flow through a cold- stream conduit of a heat-exchanger of the gas-turbine during at least part of the time which the fuel supplying is suspended.

In some embodiments, a controller is configured to set a heat- exchanger hot-stream valve to reduce (in some embodiments, to the extent of substantially entirely blocking) air flow through a hot-stream conduit of a heat-exchanger of the gas-turbine during at least part of the time which the fuel supplying is suspended.

In some embodiments, a controller is configured to set a combustor-flow valve to reduce (in some embodiments, to the extent of substantially entirely blocking) air flow through a combustor during at least part of the period of time during which the fuel supplying is suspended.

In some embodiments, a controller is configured to activate a motor to rotate the compressor of the gas-turbine during at least part of the period of time during which the supplying of fuel is suspended. In some embodiments, the activation is with reference to a speed of rotation of the compressor. In some embodiments, the activation is intermittent. In some embodiments, the activation is continuous. In some embodiments, the activation is to maintain a certain rotational speed. In some embodiments the activation is to maintain the compressor rotating at not less than about 30%, not less than about 40%, not less than about 50%, not less than about 60% and even not less than about 70% of a designed optimal rotational speed of the compressor of the gas-turbine. In some embodiments the activation is to maintain the compressor rotating at a rotational speed within an ignition rotation window.

In some embodiments, a controller comprises a manual override. In some such embodiments, the manual override allows an operator to prevent the automatic suspension of the supplying of fuel. In some such embodiments, the manual override allows an operator to substantially immediately resume the supplying of fuel.

Hybrid gas-turbine electric vehicle

A vehicle for implementing the teachings herein may be any suitable vehicle. In some embodiments, a vehicle for implementing the teachings herein is a vehicle as described herein.

According to an aspect of some embodiments of the invention, there is provided a hybrid gas-turbine electric vehicle, comprising: a) a power management unit; b) at least one electric drive motor for driving the vehicle using electric power provided by the power management unit; c) at least one gas-turbine including a turbine, a combustor, a compressor and a fuel-supply unit (e.g., generally comprising a fuel pump and the like), functionally associated with at least one generator to generate electric power from mechanical power produced by the gas-turbine, and to provide the generated power to the power management unit; d) a chargeable power storage unit for storing electric power received from the power management unit and for releasing stored power to the power management unit; and e) a controller configured to suspend the supplying of fuel to the combustor by the fuel- supply unit when the compressor is rotating. In some embodiments, the controller is configured to automatically suspend the supplying of fuel.

A hybrid gas-turbine electric vehicle may be any suitable vehicle type, as described above. In some embodiments, the vehicle is a wheeled vehicle, for instance a vehicle selected from the group of automobiles, minibuses, buses, light trucks and heavy trucks. In some embodiments, vehicle of the invention is a track-riding vehicle.

Controller

In some embodiments, the controller is an independent unit. In some embodiments, the controller is a component of a gas-turbine controller. In some embodiments, the controller is a component of the power management unit. In some embodiments, the controller is a component of at least two different assemblies of the vehicle, for example some parts of the controller are components of a gas-turbine controller and some parts of the controller are components of the power-management unit.

In some embodiments, the controller is configured to automatically resume a suspended supplying of fuel to the combustor by the fuel-supply unit while the compressor is still rotating.

In some embodiments, the vehicle further comprises an ignitor functionally associated with the combustor, and the controller is configured to automatically resume a suspended supplying of fuel to the combustor by the fuel-supply unit while the compressor is still rotating and concurrently to activate the ignitor to resume fuel combustion in the combustor.

In some embodiments, the vehicle further comprises a compressor-rotating motor functionally associated with the compressor, configured to rotate the compressor during a period of time when the supplying of fuel is suspended. In some embodiments, the compressor-rotating motor is an electric motor.

In some embodiments, the controller is configured to activate the compressor-rotating motor during at least part of the period of time when the supplying of fuel is suspended. In some such embodiments, the controller is configured to activate the motor to intermittently rotate the compressor during at least part of the period of time when the supplying of fuel is suspended. In some such embodiments, the controller is configured to activate the motor to continuously rotate the compressor during at least part of the period of time when the supplying of fuel is suspended.

In some embodiments, the compressor-rotating motor (under control of the controller) is configured to maintain the compressor rotating at a rotational speed within an ignition rotation window. In some embodiments, the compressor-rotating motor (under control of the controller) is configured to maintain the compressor rotating at a rotational speed of not less than about 30%, not less than about 40%, not less than about 50%, not less than about 60% and even not less than about 70% of designed optimal rotational speed during at least part of the period of time when the supplying of fuel is suspended.

In some embodiments, the vehicle further comprises a turbine inlet valve under control of the controller configured to regulate (to increase, to decrease, to substantially block) air flow into the turbine when the compressor is rotating. In some such embodiments, the turbine inlet valve is configured to reduce air flow into the turbine during at least part of the period of time when the supplying of fuel to the combustor is suspended by the controller, which in some embodiments substantially reduces load on the compressor. In some embodiments, the gas-turbine is configured to operate according to a Brayton cycle and the vehicle further comprises a compressor outlet valve under control of the controller, configured to direct at least some of air flow (in some embodiments, substantially all air flow) from an outlet of the compressor to the surroundings when the compressor is rotating. In some such embodiments, the compressor outlet valve is configured to direct at least some of air flow from an outlet of the compressor to the surroundings during at least part of the period of time when the supplying of fuel to the combustor is suspended by the controller, which in some embodiments substantially reduces load on the compressor.

In some embodiments, the gas-turbine is configured to operate according to an inverse Brayton cycle and the vehicle further comprises a compressor inlet valve under control of the controller, configured to direct at least some air flow (in some embodiments, substantially all air flow) into an inlet of the compressor without passing through the turbine when the compressor is rotating. In some such embodiments, the compressor inlet valve is configured to direct at least some air flow into an inlet of the compressor without passing through the turbine during at least part of the period of time when the supplying of fuel to the combustor is suspended by the controller, which in some embodiments substantially reduces load on the compressor.

In some embodiments, the vehicle further comprises a turbine/compressor clutch between the turbine and the compressor under control of the controller, the turbine/compressor clutch configured, when engaged, to lock the turbine and compressor together to rotate together and, when disengaged, to decouple the turbine and the compressor. In some such embodiments, the turbine/compressor clutch is configured to disengage during at least part of the period of time when the supplying of fuel to the combustor is suspended by the controller, which in some embodiments substantially reduces load on the compressor. Any suitable type of clutch may be used in implementing a turbine/compressor clutch, for example plate or disk clutches, cone clutches, electromagnetic clutches, magnetic particle clutches and hydraulic clutches.

In some embodiments, the vehicle further comprises a heat-exchanger (e.g. , a regenerator or a recuperator) functionally associated with the gas-turbine having a hot-stream conduit through which heat is removed from exhaust passing therethrough and a cold-stream conduit through which the removed heat heats cooler air passing therethrough prior to entering the combustor. Suitable heat-exchangers are well-known in the art and are available, for example, from Wilson TurboPower Inc., Woburn, Massachusetts, USA; Bowman Power Group Ltd, Southampton, Hants, UK; and Doty Scientific Inc, Columbia, South Carolina, USA.

In some embodiments, the vehicle further comprises a heat-exchanger cold-stream valve under control of the controller, the valve configured to regulate (to increase, to reduce, to substantially block) air flow through the cold-stream conduit of the heat-exchanger when the compressor is rotating. In some such embodiments, the heat-exchanger cold-stream valve is configured to reduce (or even substantially block) air flow through the cold-stream conduit during at least part of the period of time when the supplying of fuel to the combustor is suspended by the controller, which in some embodiments substantially reduces load on the compressor.

In some embodiments, the vehicle further comprises a heat-exchanger hot-stream valve under control of the controller, the valve configured to regulate (to increase, to reduce, to substantially block) air flow through the hot-stream conduit of the heat-exchanger when the compressor is rotating. In some such embodiments, the heat-exchanger hot-stream valve is configured to reduce (or even substantially block) air flow through the hot-stream conduit during at least part of the period of time when the supplying of fuel to the combustor is suspended by the controller, which in some embodiments substantially reduces load on the compressor.

In some embodiments, reducing or even substantially blocking the cold-stream conduit and/or the hot-stream conduit when the supplying of fuel is suspended substantially reduces the rate of cooling of the heat-exchanger, in some embodiments saving energy and increasing gas-turbine efficiency.

In some embodiments, the vehicle further comprises a combustor-flow valve under control of the controller, the combustor-flow valve configured to regulate (to increase, to reduce, to substantially block) air flow into the combustor when the compressor is rotating. In some such embodiments, the combustor-flow valve is configured to reduce (or even substantially block) air flow into the combustor during at least part of the period of time when the supplying of fuel to the combustor is suspended by the controller, which in some embodiments substantially reduces the rate of cooling of the combustor, in some embodiments saving energy and increasing gas-turbine efficiency.

Gas-turbine and generator

A hybrid gas-turbine electric vehicle as described herein comprises at least one gas- turbine configured to allow suspension and resumption of the supplying of fuel as described herein, the gas-turbine functionally associated with at least one generator to produce electric power from mechanical power produced by the gas-turbine, and to provide the generated power to the power management unit, similarly to of hybrid electric vehicles known in the art, for example hybrid gas-turbine electric vehicles such as described, for example, in US 6,526,757 and by Capata R and Sciubba E in Int. J. Energy Res. 2006, 30, 671-684.

In some embodiments, the vehicle comprises a single gas-turbine having a single designed power output, for example operating according to a Brayton or inverse Brayton cycle. In some such embodiments, the designed power output is sufficient for high-power driving of the vehicle.

In some embodiments, for a sedan automobile (1500-2000 kg) the designed power output is sufficient for driving the vehicle at high speed (160 - 200 kilometers per hour) with an average cargo (2 passengers and 1 operator for an automobile).

In some embodiments, the designed power output is sufficient for moderately high- power driving of the vehicle. In some such embodiments for a sedan automobile such power output is sufficient for driving the vehicle at highway speeds (120 - 140 kilometers per hour) with an average cargo (2 passengers and 1 operator for an automobile).

In some embodiments, the vehicle comprises two (or more) gas-turbines, each having a designed power output, that can be operated singly or together, or comprises a multipower gas-turbine, such as described in US 6,526,757. In some such embodiments, the gas-turbine is configured to efficiently provide at least two power outputs: a "high-power" and a "low- power" output.

In some embodiments, a "low-power output" is sufficient for driving the vehicle under standard conditions. In some embodiments, for a sedan automobile (1500-2000 kg) "low-power output" is sufficient for driving the vehicle at moderate extra urban speeds (80 to 90 kilometers per hour) with an average cargo (2 passengers and 1 operator for an automobile). In some embodiments, the low-power output is no more than about 50%, no more than about 40% and even no more than about 35% of the high-power output. In some embodiments, the low-power output is no less than about 10%, no less than about 20% and even no less than about 30% of the high-power output.

In some embodiments, a "high-power output" is sufficient for high power driving the vehicle. In some embodiments, for a sedan automobile "high-power output" is sufficient for driving the vehicle at high speed (160 - 200 kilometers per hour) with an average cargo (2 passengers and 1 operator for an automobile). As noted above, a vehicle as described herein comprises at least one generator to generate electric power from mechanical power produced by the gas-turbine, and to provide the generated electrical power to the power management unit.

In some embodiments, the vehicle further comprises a gas-turbine/generator clutch between the gas-turbine and the generator under control of the controller.

In some embodiments, the generator is also configured to operate as an electrical motor, to rotate the compressor of the gas-turbine during at least part of the period time when supplying of fuel is suspended.

In some embodiments, the controller is configured to activate the generator to rotate the compressor during at least part of the period of time when the supplying of fuel is suspended. In some embodiments the controller is configured to activate the generator to intermittently rotate the compressor of the gas-turbine. In some embodiments, controller is configured to activate the generator to continuously rotate the compressor of the gas-turbine. In some such embodiments, the generator is configured to receive power from the power management unit for the rotating of the compressor of the gas-turbine.

In some embodiments, the generator is configured (under control of the controller) to maintain the compressor at a rotational speed of not less than about 30%, not less than about 40%, not less than about 50%, not less than about 60% and even not less than about 70% of designed optimal rotational speed during at least part of the period of time when the supplying of fuel is suspended.

In some embodiments, the vehicle further comprises a gas -turbine/generator clutch between the gas-turbine and the generator under control of the controller, the gas- turbine/generator clutch configured, when engaged, to lock a shaft of the gas-turbine and the rotor of the generator together to rotate together and, when disengaged, to decouple the shaft and the rotor. In some such embodiments, the gas-turbine/generator clutch is configured to disengage during at least part of the period of time when the supplying of fuel to the combustor is suspended by the controller, which in some embodiments substantially reduces load on the compressor. Electric drive motors

In some embodiments, a hybrid gas-turbine electric vehicle as described herein comprises at least one electric drive motor to provide the motive force to move the vehicle, similarly to all-electric or hybrid ICE electric vehicles known in the art. In some embodiments, a hybrid gas-turbine vehicle has a single drive motor functionally associated with one or more wheel axes. In some embodiments, a hybrid gas- turbine vehicle has two drive motors, in some embodiments each functionally associated with a different drive wheel or a different wheel axis. In some embodiments, a hybrid gas-turbine electric vehicle has more than two drive motors, e.g., three, four or more drive motors. Suitable electric drive motors are commercially available, for example from NovaTorqueJnc, California, USA.

Rechargeable power storage unit

In some embodiments, a hybrid gas-turbine electric vehicle as described herein comprises a rechargeable power storage unit for storing electric power received from the power management unit and for releasing stored power as electric power to the power management unit.

Any suitable rechargeable power storage unit may be used, for example power storage assemblies known in the art of all-electric and hybrid ICE electric vehicles, for example a battery pack, a capacitor, a gyroscopic power storing unit and combinations thereof.

In some embodiments, a power storage unit comprises a battery pack. In such embodiments, electric power received from the power management unit is stored as chemical energy and is released, when required, as electric power. Any suitable battery chemistry may be used, for example lead-acid, nickel cadmium, nickel metal hydride, lithium ion, lithium ion polymer, zinc air and molten salt chemistry.

In some embodiments, a power storage unit comprises a capacitor, for example an ultracapacitor such as is available from Maxwell Technologies (San Diego, CA, USA) or as described in US 6,787,235 or US 6,602,742.

In some embodiments, a power storage unit comprises both a capacitor and a battery pack.

Power storage unit charge-state indicator

In some embodiments, a vehicle comprises a power storage unit charge-state indicator that monitors or detects the charge- state of a power storage unit (e.g., as a percentage of maximum charge). Suitable power storage unit charge- state indicators are known in the art of all-electric vehicles. Power management unit

A hybrid gas-turbine electric vehicle generally comprises a power management unit. In general terms, a power management unit accepts power from power- supplying components of the vehicle and distributes the power to power-using components. A power management unit generally functions in accordance with commands received by a vehicle operator, for example through an operator interface. In some embodiments, a power management unit is configured to change the characteristics of a power received from a power- supplying component to characteristics of a power required from a power-using component. Characteristics that are typically changed include AC to DC conversion, DC to AC conversion, phase of AC power, frequency of AC power and voltage. A typical power management unit includes control circuitry, power transmission circuitry, switches, transformers, rectifiers, inverters and control processors. A power management unit useful for implementing the teachings of the invention is similar to power management units used in hybrid ICE electric vehicles.

In some embodiments, the main power-using components of a vehicle are the drive motor or motors. The amount of power required by the at least one drive motor and provided by the power management unit is determined primarily by the vehicle operator and may range from substantially no power when the vehicle is stopped to maximal power for high-speed driving, for climbing hills or transporting heavy cargo. In some embodiments, the amount of power required is communicated to the power management unit by the vehicle operator using an operator interface. In some embodiments an operator interface resembles operator interfaces known in the art of motor vehicles including an acceleration pedal and a braking pedal (commonly used in automobiles), or accelerator and braking handles (commonly used in motorcycles).

Additional power-using components are the auxiliary loads such as air-conditioners.

An important power- supplying component is the at least one generator. In some embodiments, the power management unit is configured to control the amount of power the generator generates by activating or deactivating a gas-turbine associated with the generator. In some embodiments, the power management unit is configured to control the amount of power the generator generates by controlling the amount of power the gas-turbine generates (more or less power at the expense of gas-turbine efficiency). In some embodiments, the power management unit is configured to control the amount of power the generator generates by implementing the teachings herein by suspending and resuming the supplying of fuel to the gas-turbine combustor as described herein. The power storage unit is both a power-using component and a power- supplying component. In some embodiments, the power management unit is configured to control the amount of electric power drawn from the power storage unit, for example to power the at least one drive motor or the auxiliary loads.

Regenerative braking unit

In some embodiments a vehicle also comprise a regenerative braking unit configured for converting kinetic energy of the vehicle to electric power. Regenerative braking units are well-known in the art of hybrid ICE electric vehicles.

In some embodiments, the electric power is used to charge the power storage unit and/or to power the at least one driving motors and/or to power an auxiliary load. In some embodiments the electric power generated by the regenerative braking unit is directed to the power management unit, e.g., for storage or use.

In some embodiments, the generator is configured to receive power from the regenerative braking unit for the rotating of the compressor of the gas-turbine.

Grid charging unit

In some embodiments a vehicle comprises a grid charging unit configured to accept electric power from an external source (e.g., an electric power grid, a dedicated vehicle recharging station) to charge the power storage unit. In some embodiments, the grid charging unit is directly coupled to the power storage unit. In some embodiments, the grid charging unit is functionally associated with the power storage unit through the power management unit. Grid charging units are well-known in the art of all-electric vehicles. Gas-turbine

As noted above, a gas-turbine for implementing the teachings herein may be any suitable gas-turbine. Gas-turbines generally include a gas-turbine to monitor and control the operation of the gas-turbine. In some embodiments, a gas-turbine for implementing the teachings herein is a gas-turbine where the controller for implementing some embodiments of the method described herein is the gas-turbine controller. In some embodiments, a gas-turbine for implementing the teachings herein is a gas-turbine including one or more of the components described herein for implementing some embodiments of the invention such as one or more valves and/or a compressor-rotating motor. Thus, according to an aspect of some embodiments of the invention, there is provided a gas-turbine suitable for use in a gas-turbine hybrid electric vehicle, comprising: a) a turbine; b) a combustor configured for combusting fuel with air and directing resulting exhaust to expand through the turbine; c) a compressor for directing air from the surroundings to the combustor; e) a fuel-supply unit (e.g. , generally comprising a fuel pump and the like) configured to regulate the supplying of fuel to the combustor; and f) a gas-turbine controller configured to suspend the supplying of fuel to the combustor by the fuel- supply unit while the compressor is rotating. In some embodiments, the gas-turbine controller is configured to suspend the supplying of fuel automatically.

In some embodiments, the gas-turbine has a single designed power output. Such a gas-turbine may be configured to operate according to any suitable cycle. In some embodiments, the gas-turbine is configured for operation according to a Brayton cycle. In some embodiments, the gas-turbine is configured for operation according to an inverse Brayton cycle. In some embodiments, the gas-turbine has at least two designed power outputs, such as described, for example, in US 6,526,757. In some embodiments, gas-turbine is a multipower gas-turbine configured for operation according to both a Brayton-cycle and an inverse Brayton cycle.

The term "designed power output" is intended to have the usual meaning of the term as used in the art of gas-turbines. Specifically, a given gas-turbine has a limited number of specific and well-defined power outputs where the gas-turbine operates at highest thermal efficiency and at a corresponding optimal rotation speed. Deviation from a designed power output leads to reduced thermal efficiency.

In some embodiments, the gas-turbine controller is configured to automatically resume a suspended supplying of fuel to the combustor by the fuel- supply unit while the compressor is still rotating.

In some embodiments, a gas-turbine further comprises an ignitor functionally associated with the combustor, and the gas-turbine controller is configured to automatically resume a suspended supplying of fuel to the combustor by the fuel- supply unit while the compressor is still rotating and concurrently to activate the ignitor to resume fuel combustion in the combustor.

In some embodiments, the gas-turbine further comprises a compressor-rotating motor functionally associated with the compressor, configured to rotate the compressor during a period of time when the supplying of fuel is suspended. In some embodiments, the compressor-rotating motor is an electric motor. In some embodiments, the gas-turbine controller is configured to activate the compressor-rotating motor during at least part of the period of time when the supplying of fuel is suspended. In some such embodiments, the gas-turbine controller is configured to activate the motor to intermittently rotate the compressor during at least part of the period of time when the supplying of fuel is suspended. In some such embodiments, the gas-turbine controller is configured to activate the motor to continuously rotate the compressor during at least part of the period of time when the supplying of fuel is suspended.

In some embodiments, the compressor-rotating motor (under control of the gas- turbine controller) is configured to maintain the compressor at a rotational speed of not less than about 30%, not less than about 40%, not less than about 50%, not less than about 60% and even not less than about 70% of designed optimal rotational speed during at least part of the period of time when the supplying of fuel is suspended.

In some embodiments, the gas-turbine further comprises a turbine inlet valve under control of the gas-turbine controller configured to regulate (to increase, to decrease, to substantially block) air flow into the turbine when the compressor is rotating. In some such embodiments, the turbine inlet valve is configured to reduce air flow into the turbine during at least part of the period of time when the supplying of fuel to the combustor is suspended by the gas-turbine controller, which in some embodiments substantially reduces load on the compressor.

In some embodiments, the gas-turbine is configured to operate according to a Brayton cycle and further comprises a compressor outlet valve under control of the gas-turbine controller, configured to direct at least some of air flow (in some embodiments, substantially all air flow) from an outlet of the compressor to the surroundings when the compressor is rotating. In some such embodiments, the compressor outlet valve is configured to direct at least some of air flow from an outlet of the compressor to the surroundings during at least part of the period of time when the supplying of fuel to the combustor is suspended by the gas-turbine controller, which in some embodiments substantially reduces load on the compressor.

In some embodiments, the gas-turbine is configured to operate according to an inverse Brayton cycle and further comprises a compressor inlet valve under control of the gas-turbine controller, configured to direct at least some air flow (in some embodiments, substantially all air flow) into an inlet of the compressor without passing through the turbine when the compressor is rotating. In some such embodiments, the compressor inlet valve is configured to direct at least some air flow into an inlet of the compressor without passing through the turbine during at least part of the period of time when the supplying of fuel to the combustor is suspended by the gas-turbine controller, which in some embodiments substantially reduces load on the compressor.

In some embodiments, the gas-turbine further comprises a turbine/compressor clutch between the turbine and the compressor under control of the gas-turbine controller, the turbine/compressor clutch configured, when engaged, to lock the turbine and compressor together to rotate together and, when disengaged, to decouple the turbine and the compressor. In some such embodiments, the turbine/compressor clutch is configured to disengage during at least part of the period of time when the supplying of fuel to the combustor is suspended by the gas-turbine controller, which in some embodiments substantially reduces load on the compressor. Any suitable type of clutch may be used in implementing a turbine/compressor clutch, for example plate or disk clutches, cone clutches, electromagnetic clutches, magnetic particle clutches and hydraulic clutches.

In some embodiments, the gas-turbine further comprises a heat-exchanger (e.g., a regenerator or a recuperator) having a hot- stream conduit through which heat is removed from exhaust passing therethrough and a cold-stream conduit through which the removed heat heats cooler air passing therethrough prior to entering the combustor. Suitable heat- exchangers are well-known in the art as listed above.

In some embodiments, the gas-turbine further comprises a heat-exchanger cold-stream valve under control of the gas-turbine controller, the valve configured to regulate (to increase, to reduce, to substantially block) air flow through the cold-stream conduit of the heat- exchanger when the compressor is rotating. In some such embodiments, the heat-exchanger cold-stream valve is configured to reduce (or even substantially block) air flow through the cold- stream conduit during at least part of the period of time when the supplying of fuel to the combustor is suspended by the gas-turbine controller, which in some embodiments substantially reduces load on the compressor.

In some embodiments, the gas-turbine further comprises a heat-exchanger hot-stream valve under control of the gas-turbine controller, the valve configured to regulate (to increase, to reduce, to substantially block) air flow through the hot-stream conduit of the heat- exchanger when the compressor is rotating. In some such embodiments, the heat-exchanger hot-stream valve is configured to reduce (or even substantially block) air flow through the hot- stream conduit during at least part of the period of time when the supplying of fuel to the combustor is suspended by the gas-turbine controller, which in some embodiments substantially reduces load on the compressor. In some embodiments, reducing or even substantially blocking the cold-stream conduit and/or the hot-stream conduit when the supplying of fuel is suspended substantially reduces the rate of cooling of the heat-exchanger, in some embodiments saving energy and increasing gas-turbine efficiency.

In some embodiments, the gas-turbine further comprises a combustor-flow valve under control of the gas-turbine controller, the combustor-flow valve configured to regulate (to increase, to reduce, to substantially block) air flow into the combustor when the compressor is rotating. In some such embodiments, the combustor-flow valve is configured to reduce (or even substantially block) air flow into the combustor during at least part of the period of time when the supplying of fuel to the combustor is suspended by the gas-turbine controller, which in some embodiments substantially reduces the rate of cooling of the combustor, in some embodiments saving energy and increasing gas-turbine efficiency.

Some aspects of the invention disclosed herein are discussed with reference to the embodiments presented hereinbelow.

An embodiment of a hybrid gas-turbine electric vehicle, vehicle 58, is schematically depicted in Figure 3A. Vehicle 58 resembles vehicle 38 schematically depicted in Figure 2 and includes a power management unit 40, a chargeable power storage unit 46 (including a battery pack, a capacitor and a charge- state indicator) for storing electric power received from power management unit 40 and for releasing stored power to power management unit 40, an operator interface, four electric drive motors each functionally associated with a vehicle wheel, a regenerative braking unit including four assemblies, each assembly functionally associated with a vehicle wheel and a grid charging unit.

Vehicle 58 also includes a power generation unit 30 including a Brayton-cycle gas- turbine 60 and a generator 24. Gas-turbine 60 is schematically depicted in Figure 3B functionally associated with generator 24 through shaft 62 and includes an air inlet 20, an exhaust duct 22, a compressor 16, a combustor 12, a turbine 14, a fuel-supply unit 26, a gas- turbine controller 64, an ignitor 76, and a heat-exchanger 32 including a hot-stream conduit 34 and a cold-stream conduit 36. When gas-turbine 60 is operated to to generate power, air is drawn into compressor 16 through air inlet 20, directed through cold-stream conduit 36 of heat-exchanger 32 into combustor 12. In combustor 12, the air is combusted with fuel supplied and regulated by fuel- supply unit 26. The hot exhaust expands through turbine 14, producing mechanical power and driving generator 24 through shaft 62. The exhaust gas is then directed through hot-stream conduit 34 of heat-exchanger 32 before release to the surroundings through exhaust duct 22. Generator 24 generates electric power from the mechanical power produced by gas-turbine 60 and provides the generated power to power management unit 40.

Gas-turbine controller 64, schematically depicted in Figure 3C is similar to gas- turbine controllers known in the art. Gas-turbine controller 64 includes a processor unit 66 functionally associatable with power management unit 40 and fuel- supply unit 26 and includes a compressor rotational- speed input 68 for accepting a current speed of rotation of compressor 16 and a manual override input 70. In addition to usual functions, processor unit 66 is configured to, based on fuel- suspension rules, automatically suspend for a period of time the supplying of fuel to combustor 12 and based on fuel-resumption rules, automatically resume the supplying of fuel to combustor 12 while compressor 16 is still rotating by controlling fuel- supply unit 26.

The fuel- suspension rules of processor unit 66 include suspension of the supplying of fuel upon receiving such a request from power management unit 40 unless there is a reason to the contrary.

The fuel-resumption rules of processor unit 66 include possible resumption of the supplying of fuel upon receiving instructions for such through manual override input 70 and possible resumption of the supplying of fuel when the rotational speed of compressor 16 approaches a lower limit as received through compressor rotational- speed input 68, the lower limit being within the ignition rotation window of gas-turbine 60, and as discussed above, in some embodiments is not less than about 30%, not less than about 40%, not less than about 50%, not less than about 60% and even not less than about 70% of the designed optimal rotational speed of the compressor.

Vehicle 58 is operated in a substantially usual way (for example as described in US 6,526,757) where power management unit 40, based on instructions received through the operator interface accepts generated power from power generation unit 30 and the regenerative braking unit and directs electric power as needed to the drive motors and auxiliary loads. When insufficient power is generated, power management unit 40 draws the extra needed power from power storage unit 46. When excess power is generated, power management unit 40 stores the extra power in power storage unit 46. Power management unit 40 together with gas-turbine controller 64 also regulates the amount of power generated by power generation unit 30 in the usual way, endeavoring to operate gas-turbine 60 at greatest efficiency, that is to say, as close as possible at the designed power output for as much time as possible. When power generation unit 30 generates power, gas-turbine controller 64 controls fuel- supply unit 26 to regulate the supply of fuel to combustor 12 to maintain fuel combustion.

When power management unit 40 identifies that power storage unit 46 has a sufficiently high state of charge (through a charge-state indicator, in some embodiments, not less than about 50%, not less than about 60%, not less than about 70% and even not less than about 80% of maximal state of charge) and that the power-requirements of vehicle 58 can be met by drawing power from power storage unit 46 and/or by power generated by the regenerative braking unit (e.g. , stopping at a traffic light, to load/offload passengers and cargo, downhill travel), power management unit 40 sends a request to gas-turbine controller 64 to suspend the supplying of fuel to combustor 12.

Unless there is a reason to the contrary, gas-turbine controller 64 controls fuel-supply unit 26 to suspend the supplying of fuel to combustor 12, stopping combustion so power generation unit 30 stops generating power. Power management unit 40 suspends the electrical load on generator 24, reducing the mechanical load on compressor 16. Compressor 16 continues rotating due to inertia but gradually slow down.

Gas-turbine controller 64 allows compressor 16 to rotate for a period of time during which supplying of fuel is suspended while continuously monitoring the speed of rotation of compressor 16 through compressor rotational- speed input 68.

When the rotational speed of compressor 16 approaches the lower limit, gas-turbine controller 64 controls fuel-supply unit 26 to resume supplying fuel to combustor 12 to substantially immediately resume the supplying of fuel and activates ignitor 76 to resume fuel combustion in combustor 12. Gas-turbine 60 resumes producing mechanical power and power generation unit 30 resumes normal operation.

Once gas-turbine 60 stabilizes, gas-turbine controller 64 returns to normal operation, including readiness to suspend the supplying of fuel again.

The lower limit of rotational speed at which gas-turbine controller 64 resumes the supplying of fuel is dependent on the specific design and operating parameters of gas -turbine 60. A person having ordinary skill in the art is able, upon perusing the description herein, to select a suitable lower limit for a given gas-turbine. In some embodiments, the lower limit is not less than about 30%, not less than about 40%, not less than about 50%, not less than about 60% and even not less than about 70% of the designed optimal rotational speed of the gas-turbine.

If during the period of time when the supplying of fuel is suspended there is a need for more power for vehicular operation than can be provided by power storage unit 46 and regenerative braking unit 54, power management unit 40 informs gas-turbine controller 64 thereof. Gas-turbine controller 64 controls fuel-supply unit 26 to resume the supply of fuel to combustor 12 to substantially immediately resume the supplying of fuel and activates ignitor 76 to resume fuel combustion substantially immediately.

During the period of time when the supplying of fuel is suspended, the operator of vehicle 58 may choose to resume the supplying of fuel and fuel combustion substantially immediately by sending an instruction to that effect from the operator interface through manual override input 70.

Anytime during operation of vehicle 58, the operator of vehicle 58 may choose to prevent the automatic suspension of the supplying of fuel as described above by sending an instructionl to that effect from the operator interface through manual override input 70.

As noted above, gas-turbine controller 64 controls fuel-supply unit 26 to suspend the supplying fuel to combustor 12 upon receiving such a request from power management unit 40 unless there is a reason to the contrary. Depending on the specific embodiment, reasons to the contrary may include reasons such as prevention of automatic suspension by operator manual override as described above, gas -turbine 60 is not operating stably, or heat-exchanger 32 is not sufficiently hot.

An embodiment of a hybrid gas-turbine electric vehicle, vehicle 72, is schematically depicted in Figure 4A. Vehicle 72 resembles vehicle 58 discussed with reference to Figures 3 with some differences.

Like vehicle 58, vehicle 72 includes a power generation unit 30 schematically depicted in Figure 4B including a Brayton-cycle gas -turbine 60 and a generator 24 functionally associated therewith through shaft 62. On shaft 62 associating gas -turbine 60 with generator 24 is gas-turbine/generator clutch 74 under control of gas-turbine controller 78. Additionally, gas-turbine 60 of vehicle 72 includes an ignitor 76 (similar to gas-turbine ignitors known in the art) under control of gas-turbine controller 78 to initiate fuel combustion in combustor 12.

Gas-turbine controller 78, schematically depicted in Figure 4C is similar to gas- turbine controller 64 schematically depicted in Figure 3C. Gas-turbine controller 78 additionally comprises a state of charge input 84 for accepting a current state of charge of battery pack 48 and capacitor 50 of power storage unit 46 from charge- state indicator 52, and a regenerative braking-power input 86. Gas-turbine controller 78 is also configured to control operation of gas-turbine/generator clutch 74 through gas-turbine/generator clutch connector 80 to reduce the load on compressor 16 during at least part of the period of time during which supplying of fuel is suspended by gas-turbine/generator clutch 74 to decouple gas-turbine 60 from generator 24. Gas-turbine controller 78 is also configured to activate ignitor 76 through ignitor connector 82.

In addition to the fuel- suspension rules of gas-turbine controller 64, the fuel- suspension rules of processor unit 66 of gas-turbine controller 78 include possible suspension of the supplying of fuel when the regenerative braking unit generates more than a certain predetermined minimum amount of power unless there is a reason to the contrary.

The fuel-resumption rules of processor unit 66 of gas-turbine controller 78 include: possible resumption of the supplying of fuel upon receiving instructions for such through manual override input 70; possible resumption of the supplying fuel when more power than available is required for vehicular operation; possible resumption of the supplying of fuel when the rotational speed of compressor 16 approaches a certain predetermined lower limit as received through compressor rotational- speed input 68; possible resumption of the supplying of fuel when a current state of charge of power storage unit 46 or a component thereof falls below a minimum value (e.g. , below 60%, below 50%, below 40% of full charge); and possible resumption of the supplying of fuel when a regenerative braking unit generates less than a minimum amount of power.

Vehicle 72 is operated in the usual way, substantially as described above. When power management unit 40 identifies that power storage unit 46 has a sufficiently high state of charge and that the power-requirements of vehicle 72 can be met by drawing power from power storage unit 46 and/or by power generated by regenerative braking unit 54, power management unit 40 sends a request to gas-turbine controller 78 to suspend the supplying of fuel to combustor 12.

Unless there is a reason to the contrary, gas-turbine controller 78 controls fuel-supply unit 26 to suspend the supplying of fuel to combustor 12. Concurrently, gas-turbine controller 78 activates gas-turbine/generator clutch 74 through gas -turbine/generator clutch connector 80 to decouple gas-turbine 60 from generator 24, reducing the load on compressor 16. Compressor 16 continues rotating due to inertia but gradually slows down, though at a lower rate than if coupled to generator 24.

Gas-turbine controller 78 allows compressor 16 to rotate for a period of time during which supplying of fuel is suspended while continuously monitoring the speed of rotation of compressor 16 through compressor rotational- speed input 68. When the rotational speed of compressor 16 approaches the lower limit, gas-turbine controller 78 controls fuel- supply unit 26 to resume supplying fuel to combustor 12 and concurrently activates ignitor 76 through ignitor connector 82 to ignite the fuel in combustor 12. Combustion of fuel in combustor 12 and gas-turbine 60 resumes producing mechanical power under control of gas-turbine controller 78. Gas-turbine controller 78 activates gas- turbine/generator clutch 74 through gas-turbine/generator clutch connector 80 to couple gas- turbine 60 to generator 24. Power generation unit 30 resumes normal operation.

Once gas-turbine 60 stabilizes, gas-turbine controller 78 returns to normal operation, including readiness to suspend the supplying of fuel again.

As with vehicle 58, the lower limit of rotational speed at which gas-turbine controller

78 resumes the supplying of fuel is within the ignition rotation window of gas-turbine 60 and is dependent on the specific design and operating parameters of gas-turbine 60 of vehicle 72.

Gas-turbine controller 78 includes fuel resumption rules allowing possible resumption of the supplying fuel when a current state of charge of power storage unit 46 or a component thereof falls below a minimum value (e.g. , below 60%, below 50%, below 40% of full charge).

For example in some embodiments, during operation of vehicle 72, if during a period of time when the supplying of fuel is suspended the state of charge of power storage unit 46 falls below a minimum value as indicated by charge- state indicator 52 through state of charge input 84, gas-turbine controller 78 controls fuel- supply unit 26 to resume the supply of fuel to combustor 12 and activates ignitor 76 combustion in combustor 12 substantially immediately.

For example in some embodiments during operation of vehicle 72, if during a period of time when the supplying of fuel is suspended the state of charge of the battery pack component of power storage component 46 (not the capacitor) falls below a minimum value as indicated by charge- state indicator 52 through state of charge input 84, gas-turbine controller 78 controls fuel- supply unit 26 to resume the supply of fuel to combustor 12 substantially immediately. In some such embodiments, the state of charge of the capacitor is not a factor for fuel-resumption.

Gas-turbine controller 78 includes fuel suspension rules allowing possible suspension of the supplying fuel when a regenerative braking unit 54 generates more than a minimum amount of power, in some embodiments for at least a minimal time. For example in some embodiments, during operation of vehicle 72 when gas-turbine 60 is generating power normally, gas-turbine controller 78 receives an indication through regenerative braking- power input 86 that regenerative braking unit 54 is generating a very high amount of power (e.g. , vehicle 72 is driving down a steep hill, sudden braking from high speed driving). Unless there is a reason to the contrary, gas-turbine controller 78 controls fuel-supply unit 26 to suspend the supplying of fuel to combustor 12, stopping combustion of fuel in combustor 12 and concurrently activates gas-turbine/generator clutch 74 to decouple gas-turbine 60 from generator 24, substantially as described above.

Gas-turbine controller 78 includes fuel resumption rules allowing possible resumption of the supplying fuel when a regenerative braking unit 54 generates less than a minimum amount of power, in some embodiments for at least a minimal time. For example in some embodiments, during operation of vehicle 72, if during a period of time when the supplying of fuel is suspended gas-turbine controller 78 receives an indication through regenerative braking-power input 86 that regenerative braking unit 54 is generating less than a minimal amount of power (e.g. , vehicle 72 is starting to drive uphill after a driving downhill) gas- turbine controller 78 controls fuel-supply unit 26 to resume the supply of fuel to combustor 12 substantially immediately.

An embodiment of a hybrid gas-turbine electric vehicle, vehicle 88, is schematically depicted in Figure 5A. Vehicle 88 resembles the vehicles discussed above with some differences.

Like the vehicles described above, vehicle 88 comprises a power generation unit 30, schematically depicted in Figure 5B including a gas-turbine controller 90, a Brayton cycle gas-turbine 60 and a generator 24 functionally associated therewith through shaft 62. Like power generation unit 30 of vehicle 72, power generation unit 30 of vehicle 88 includes an ignitor 76 under control of gas-turbine controller 90. Generator 24 of vehicle 88 is configured to function as an electric compressor-rotating motor to rotate compressor 16 under control of gas-turbine controller 90.

Gas-turbine 60 of vehicle 88 includes a compressor-outlet valve 92 under control of gas-turbine controller 90, having two states. In a first, operating, state compressor-outlet valve 92 directs air exiting compressor 16 in the usual way to cold- stream conduit 36 of heat- exchanger 32 as depicted in Figure 5B. In a second, shunting, state (not depicted) compressor-outlet valve 92 directs substantially all air exiting compressor 16 to the surroundings. Compressor-outlet valve 92 also blocks air flow through turbine 14 and therefore also functions as a turbine inlet valve to regulate air flow into turbine 14. Compressor-outlet valve 92 also blocks air flow through hot-stream conduit 34 of heat- exchanger 32 and therefore also functions as a heat-exchanger hot-stream valve to regulate air flow through hot-stream conduit 34. Compressor-outlet valve 92 also blocks air flow through cold-stream conduit 36 of heat-exchanger 32 and therefore also functions as a heat- exchanger cold- stream valve to regulate air flow through cold- stream conduit 36. Compressor-outlet valve 92 also blocks air flow into combustor 12 and therefore also functions as a combustor-flow valve to regulate air flow into combustor 12.

Gas-turbine controller 90, schematically depicted in Figure 5C is similar to gas- turbine controllers discussed above. Gas-turbine controller 90 is additionally configured to control operation of compressor-outlet valve 92 through compressor-outlet valve connector 96 to reduce the load on compressor 16 during at least part of the period of time during which supplying of fuel is suspended by setting compressor-outlet valve 92 to the shunting state. Gas-turbine controller 90 is additionally configured to activate generator 24 as a compressor- rotating motor through compressor-rotating motor connector 94. Gas-turbine controller 90 is also configured to activate ignitor 76 through ignitor connector 82. Gas-turbine controller 90 also comprises a combustor-temperature input 98 for accepting a current temperature of combustor 12.

The fuel-resumption rules of processor unit 66 of gas-turbine controller 90 include: possible resumption of the supplying of fuel upon receiving instructions for such through manual override input 70, possible resumption of the supplying of fuel when more power than available is required for vehicular operation, for example for operating drive motors 44 and possible resumption of the supplying of fuel when a current state of charge of power storage unit 46 or a component thereof falls below a minimum value; and possible resumption of the supplying of fuel when a current combustor temperature approaches a lower limit that makes reignition inefficient as received through combustor-temperature input 98.

Vehicle 88 is operated in the usual way, substantially as described above. When power management unit 40 identifies that power storage unit 46 has a sufficiently high state of charge and that the power-requirements of vehicle 88 can be met by drawing power from power storage unit 46 and/or by power generated by regenerative braking unit 54, power management unit 40 sends a request to gas-turbine controller 90 to suspend the supplying of fuel to combustor 12.

Unless there is a reason to the contrary, when power management unit 40 sends a request to gas-turbine controller 90 to suspend the supplying of fuel to combustor 12, gas- turbine controller 90 controls fuel- supply unit 26 to suspend the supplying of fuel to combustor 12. Concurrently, gas-turbine controller 90 sets compressor-outlet valve 92 through compressor-outlet valve connector 96 to the shunting state, directing substantially all air from the outlet of compressor 16 to the surroundings, reducing the load on compressor 16.

During at least part of the period time during which supplying of fuel is suspended, gas-turbine controller 90 activates (continuously or intermittently) generator 24 through compressor-rotating motor connector 94 as a compressor rotating motor to rotate compressor 16 using power received from power storage unit 46 and/or regenerative braking unit 54 through power management unit 40, thereby maintaining the rotational speed of compressor 16 above a predetermined minimum. Such active rotating of compressor 16 has a number of advantages compared to allowing a compressor to rotate by inertia. Excess power (e.g. , generated by regenerative braking unit 54 or stored in power storage unit 46) which would otherwise be wasted is used. The maximal period of time during which fuel supplying is suspended is increased. Active rotating of compressor 16 allows the rotational speed of compressor 16 to be substantially higher when fuel supplying is resumed, in some embodiments allowing quicker gas-turbine stabilization and/or reduced turbine lag.

In some embodiments, the load on compressor 16 is substantially reduced because substantially all air from the outlet of compressor 16 is directed to the surroundings by compressor-outlet valve 92. As a result less power is required to rotate compressor 16 for a longer time at higher rotational speeds.

The rotational speed at which compressor 16 is maintained by gas-turbine generator 24 operating as a compressor-rotating motor is dependent on the specific design and operating parameters of gas -turbine 60 and is generally within the ignition rotation window of gas-turbine 60. In some embodiments, the rotational speed is the highest possible speed with the ignition rotation window so that gas-turbine stabilization is as quick as possible subsequent to resumption of combustion.

During the period of time during which supplying of fuel is suspended, gas-turbine controller 90 compares information received, including from components of gas -turbine 60 and power management unit 40, to the fuel-resumption rules to resume the supplying of fuel when required.

For example, when the appropriate instruction is received through manual override input 70, gas-turbine controller 90 controls fuel-supply unit 26 to resume the supplying of fuel.

For example, when power management unit 40 informs gas-turbine controller 90 that more power is needed for operating drive motors 44, gas-turbine controller 90 controls fuel- supply unit 26 to resume the supplying of fuel. For example, when the current termperature of combustor 12 as received through combustor-temperature input 98 approaches a lower limit that makes reignition inefficient (e.g. , more polluting, long time to stabilize) as received through combustor-temperature input 98, gas-turbine controller 90 controls fuel-supply unit 26 to resume the supplying of fuel.

For example, when a current state of charge of power storage unit 46 or a component thereof falls below a minimum value (as discussed with reference to vehicle 72), gas-turbine controller 90 controls fuel-supply unit 26 to resume the supplying of fuel.

When sufficient fuel-resumption rules are met, gas-turbine controller 90 sets compressor-outlet valve 92 to the operating state depicted in Figure 5B, controls fuel-supply unit 26 to resume the supplying of fuel and activates ignitor 76 to resume combustion, and stops activating generator 24 as a compressor rotating motor. Power generation unit 30 resumes normal operation.

As compressor-outlet valve 92 blocks the passage of cold air through cold-stream conduit 36 of heat-exchanger 32 during at least part of the period of time when the supplying of fuel is suspended, in some embodiments heat-exchanger 32 retains much of the previously stored heat. As compressor-outlet valve 92 blocks the entry of air into combustor 12 during at least part of the period of time when the supplying of fuel is suspended, in some embodiments combustor 12 cools at a relatively moderate rate and retains much of the previously stored heat. As generator 24 operates as a compressor rotating motor during at least part of the period of time when the supplying of fuel is suspended, in some embodiments compressor 16 has a rotational speed that is relatively high and, in some embodiments, substantially close to the rotation speed at which gas-turbine 60 is designed to operate at the highest efficiency. Depending on the embodiments, as a result of one or more of these factors gas-turbine more quickly stabilizes and/or more quickly operates efficiently.

Once gas-turbine 60 is operating sufficiently stably, gas-turbine controller 90 returns to normal operation, including readiness to suspend the supplying of fuel.

An embodiment of a hybrid gas-turbine electric vehicle, vehicle 100, is schematically depicted in Figure 6A. Vehicle 100 resembles the vehicles discussed above with some differences.

Like the vehicles described above, vehicle 100 comprises a power generation unit 30, schematically depicted in Figure 6B including a gas-turbine controller 102, a Brayton cycle gas-turbine 60 and a generator 24 functionally associated therewith through shaft 62. Like power generation unit 30 of vehicle 72 schematically depicted in Figure 4B, power generation unit 30 of vehicle 100 includes an ignitor 76 under control of gas-turbine controller 102. On shaft 18 connecting compressor 16 with turbine 14 is compressor/turbine clutch 104 under control of gas-turbine controller 102. Additionally, gas-turbine 60 includes an electric compressor rotating motor 106 functionally associated with compressor 16 under control of gas-turbine controller 102.

Gas-turbine controller 102 of vehicle 100 schematically depicted in Figure 6C, similar to the gas-turbine controllers discussed above, is additionally configured to activate (continuously or intermittently) compressor rotating motor 106 through compressor rotating motor connector 94 to rotate compressor 16 during at least part of the period of time during which the supplying of fuel is suspended in order to maintain the speed of rotation of compressor 16 with reference to the speed of rotation as received through compressor rotational- speed input 68 as described above for gas-turbine controller 90 of vehicle 88. Gas- turbine controller 102 is also configured to control operation of compressor/turbine clutch 104 through compressor/turbine clutch connector 108 to reduce the load on compressor 16 during at least part of the period of time during which supplying of fuel is suspended by activating compressor/turbine clutch 104 to decouple compressor 16 from turbine 14. Gas- turbine controller 102 is also configured to activate ignitor 76 through ignitor connector 82. Gas-turbine controller 102 also comprises a combustor-temperature input 98 for accepting a current temperature of combustor 12.

The fuel-resumption rules of processor unit 66 of gas-turbine controller 102 include: possible resumption of the supplying of fuel upon receiving instructions for such through manual override input 70; possible resumption of the supplying fuel when more power than available is required for vehicular operation, for example for operating drive motors 44; and possible resumption of the supplying of fuel when a current state of charge of power storage unit 46 or a component thereof falls below a minimum value.

Vehicle 100 is operated in the usual way, substantially as described above. When power management unit 40 identifies that power storage unit 46 has a sufficiently high state of charge and that the power-requirements of vehicle 100 can be met by drawing power from power storage unit 46 and/or by power generated by regenerative braking unit 54, power management unit 40 sends a request to gas-turbine controller 102 to suspend the supplying of fuel to combustor 12.

Unless there is a reason to the contrary, gas-turbine controller 102 controls fuel- supply unit 26 to suspend the supplying of fuel to combustor 12. Concurrently, gas-turbine controller 102 activates compressor/turbine clutch 104 to decouple compressor 16 from turbine 14, reducing the load on compressor 16.

During at least part of the period time during which supplying of fuel is suspended, gas-turbine controller 102 activates (continuously or intermittently) compressor rotating motor 106 to rotate compressor 16 using power received from power storage unit 46 and/or regenerative braking unit 54 through power management unit 40, thereby maintaining the rotational speed of compressor 16 above a predetermnined minimum. As discussed with reference to vehicle 88, such active rotating of compressor 16 has a number of advantages.

Due to decoupling of compressor 16 from turbine 14, the load on compressor 16 is substantially reduced. As a result, in some embodiments less power is required to rotate compressor 16 for a longer time at higher rotational speeds. As discussed above, the rotational speed at which compressor 16 is maintained by compressor rotating motor 106 is dependent on the specific design and operating parameters of gas-turbine 60.

During the period of time during which supplying of fuel is suspended, gas-turbine controller 102 compares information received, including from components of gas-turbine 60 and power management unit 40, to the fuel-resumption rules to resume the supplying of fuel when required.

For example, when the appropriate instruction is received through manual override input 70, gas-turbine controller 102 controls fuel-supply unit 26 to resume the supplying of fuel.

For example, when power management unit 40 informs gas-turbine controller 102 that more power is needed for operating drive motors 44, gas-turbine controller 102 controls fuel- supply unit 26 to resume the supplying of fuel.

For example, when current the state of charge of power storage unit 46 or a component thereof falls below a minimum value (as discussed with reference to vehicle 72), gas-turbine controller 102 controls fuel-supply unit 26 to resume the supplying of fuel.

When sufficient fuel-resumption rules are met, gas-turbine controller 102 controls fuel-supply unit 26 to resume the supplying of fuel, activates compressor/turbine clutch 104 through compressor/turbine clutch connector 108 to connect compressor 16 to turbine 14 and and activates ignitor 76 through ignitor connector 82 to ignite the fuel in combustor 12. Combustion of fuel in combustor 12 resumes and power generation unit 30 resumes normal operation.

Once gas-turbine 60 is operating sufficiently stably, gas-turbine controller 102 returns to normal operation, including readiness to suspend the supplying of fuel. An embodiment of a hybrid gas-turbine electric vehicle, vehicle 110, is schematically depicted in Figure 7A. Vehicle 110 resembles the vehicles discussed above with some differences.

Vehicle 110 comprises a power generation unit 30, schematically depicted in Figure

7B, including a gas-turbine controller 112, an inverse-Brayton cycle gas-turbine 114 and a generator 24 functionally associated therewith through shaft 62. Like power generation unit 30 of vehicle 100, power generation unit 30 of vehicle 110 includes an ignitor 76 under control of gas-turbine controller 112 to initiate fuel combustion in combustor 12. On shaft 18 connecting compressor 16 with turbine 14 is compressor/turbine clutch 104 under control of gas-turbine controller 112. Additionally, generator 24 of vehicle 110 is configured to function as an electric compressor-rotating motor to rotate compressor 16 under control of gas-turbine controller 112.

Gas-turbine 114 of vehicle 110 includes a compressor-inlet valve 116 under control of gas-turbine controller 112, having two states. In a first, operating, state depicted in Figure 7B, compressor-inlet valve 116 directs air exiting hot-stream conduit 34 of heat-exchanger 32 into compressor 16 in the usual way. In a second, shunting, state (not depicted) of compressor-inlet valve 116, compressor 16 draws air from the surroundings and not from hot-stream conduit 34 of heat-exchanger 32. Compressor-inlet valve 116 also blocks air flow through turbine 14 and therefore also functions as a turbine inlet valve to regulate air flow into turbine 14. Compressor- inlet valve 116 also blocks air flow through hot-stream conduit 34 of heat-exchanger 32 and therefore also functions as a heat-exchanger hot-stream valve to regulate air flow through hot-stream conduit 34. Compressor-inlet valve 116 also blocks air flow through cold- stream conduit 36 of heat-exchanger 32 and therefore also functions as a heat-exchanger cold-stream valve to regulate air flow through cold-stream conduit 36. Compressor- inlet valve 116 also blocks air flow through combustor 12 and therefore also functions as a combustor-flow valve to regulate air flow into combustor 12.

Gas-turbine controller 112 of vehicle 110 schematically depicted in Figure 7C, similar to the gas-turbine controllers discussed above, is configured to activate generator 24 as a compressor rotating motor through compressor rotating motor connector 94 to rotate compressor 16 during at least part of the period of time during which the supplying of fuel is suspended in order to maintain the speed of rotation of compressor 16 above a predetermined minimum, with reference to the speed of rotation as received through compressor rotational- speed input 68. Gas-turbine controller 112 is also configured to control operation of compressor-inlet valve 116 through compressor-inlet valve connector 118 to reduce the load on compressor 16 during at least part of the period of time during which supplying of fuel is suspended by setting compressor-inlet valve 116 to the shunting state. Gas-turbine controller 112 is also configured to control operation of compressor/turbine clutch 104 through compressor/turbine clutch connector 108 to activate ignitor 76 through ignitor connector 82 analogously to gas-turbine controller 102 of vehicle 100. Gas-turbine controller 112 also comprises a combustor-temperature input 98 for accepting a current temperature of combustor 12.

The fuel-resumption rules of processor unit 66 of gas-turbine controller 112 include: possible resumption of the supplying of fuel upon receiving instructions for such through manual override input 70, possible resumption of the supplying of fuel when more power than available is required for vehicular operation, for example for operating drive motors 44; and possible resumption of the supplying of fuel when a current state of charge of power storage unit 46 or a component thereof falls below a minimum value.

Vehicle 110 is operated in the usual way, substantially as described above. When power management unit 40 identifies that power storage unit 46 has a sufficiently high state of charge and that the power-requirements of vehicle 110 can be met by drawing power from power storage unit 46 and/or by power generated by regenerative braking unit 54, power management unit 40 sends a request to gas-turbine controller 112 to suspend the supplying of fuel to combustor 12.

Unless there is a reason to the contrary, gas-turbine controller 112 controls fuel- supply unit 26 to suspend the supplying of fuel to combustor 12. Concurrently, gas-turbine controller 112 activates compressor/turbine clutch 104 to decouple compressor 16 from turbine 14 and sets compressor- inlet valve 116 through compressor-inlet valve connector 118 to the shunting state, so that compressor 16 draws air from the surroundings and not from hot-stream conduit 34, reducing the load on compressor 16.

During at least part of the period time during which supplying of fuel is suspended, gas-turbine controller 112 activates (continuously or intermittently) generator 24 as a compressor-rotating motor to rotate compressor 16 using power received from power storage unit 46 and/or regenerative braking unit 54 through power management unit 40, thereby maintaining the rotational speed of compressor 16 above a predetermnined minimum.

Due to decoupling of compressor 16 from turbine 14, the load on compressor 16 is substantially reduced. As a result, in some embodiments less power is required to rotate compressor 16 for a longer time at higher rotational speeds. In some embodiments, the load on compressor 16 is substantially reduced because compressor 16 draws air through a short intake passage from the surroundings. As a result less power is required to rotate compressor 16 for a longer time at higher rotational speeds.

The rotational speed at which compressor 16 is maintained by gas-turbine generator 24 operating as a compressor-rotating motor is dependent on the specific design and operating parameters of gas-turbine 114 as discussed with reference to vehicles 88 and 100.

During the period of time during which supplying of fuel is suspended, gas-turbine controller 112 compares information received, including from components of gas-turbine 112 and power management unit 40, to the fuel-resumption rules to resume the supplying of fuel when required.

For example, when the appropriate instruction is received through manual override input 70, gas-turbine controller 112 controls fuel-supply unit 26 to resume the supplying of fuel.

For example, when power management unit 40 informs gas-turbine controller 112 that more power is needed for operating drive motors 44, gas-turbine controller 112 controls fuel- supply unit 26 to resume the supplying of fuel.

For example, when current the state of charge of power storage unit 46 or a component thereof falls below a minimum value (as discussed with reference to vehicle 72 or 100), gas-turbine controller 112 controls fuel-supply unit 26 to resume the supplying of fuel.

When sufficient fuel-resumption rules are met, gas-turbine controller 112 controls fuel-supply unit 26 to resume the supplying of fuel, sets compressor-inlet valve 116 to the operating state, stops activating generator 24 as a compressor rotating motor, and activates compressor/turbine clutch 104 through compressor/turbine clutch connector 108 to connect compressor 16 to turbine 14. Gas-turbine controller 112 activates ignitor 76 through ignitor connector 82 to ignite the fuel in combustor 12. In this context, it is important to remember that since compressor-inlet valve 116 blocks the passage of cold air through components of gas-turbine 114 during at least part of the period of time when the supplying of fuel is suspended, in some embodiments such components retain much of the previously stored heat, substantially as discussed with reference to vehicle 88. Power generation unit 30 resumes normal operation.

Once gas-turbine 114 is operating sufficiently stably, gas-turbine controller 112 returns to normal operation, including readiness to suspend the supplying of fuel. A power generation unit 120 suitable for use with an embodiment of a hybrid gas- turbine electric vehicle (not depicted) is schematically depicted in Figures 8A-8D.

Power generation unit 120 comprises a multipower gas-turbine 122 configured in accordance with the teachings of US 6,526,757 and a generator 24 functionally associated therewith through shaft 62.

As described in US 6,526,757, gas-turbine 122 comprises two sets of three valves. When valves 124a, 124b and 124c are open and valves 126a, 126b and 126c are closed as schematically depicted in Figure 8 A, gas -turbine 122 is configured to operate according to a Brayton cycle. When valves 124a, 124b and 124c are closed and valves 126a, 126b and 126c are open as schematically depicted in Figure 8B, gas -turbine 122 is configured to operate according to an inverse Brayton cycle.

Additionally, gas-turbine 122 is configured to implement aspects of the invention described herein. Specifically, gas-turbine 122 includes a gas-turbine controller 128 that is configured to control valves 124 and 126 in accordance with the teachings of US 6,526,757 and is also configured to automatically suspend the supplying of fuel to combustor 12 by fuel- supply unit 26 while compressor 16 is rotating and to automatically resume the supplying of fuel to combustor 12 by fuel-supply unit 26 while compressor 16 is still rotating, substantially as described herein.

Gas-turbine controller 128 is similar to gas-turbine controller 112 of vehicle 110 including configuration to activate ignitor 76 to ignite fuel in combustor 12. Gas-turbine controller 128 is similar to gas-turbine controller 90 of vehicle 88 including configuration to control generator 24 to rotate compressor 16 during at least part of the period time when the supplying of fuel is suspended.

Gas-turbine controller 128, like gas-turbine controllers 90 and 112 is also configured to activate an additional vehicular component, specifically valves 124 and/or 126 to reduce a load on compressor 16 during at least part of the period of time during which supplying of fuel is suspended.

A vehicle including power generation unit 120 comprising gas-turbine 122 is operated in the usual way either according to a Brayton cycle or an inverse-Brayton cycle.

When the supplying of fuel is suspended as described herein when gas -turbine 122 is operating according to a Brayton cycle as schematically depicted in Figure 8A, gas-turbine controller 128 concurrently sets valve 126a to an open state, as schematically depicted in Figure 8C. As a result, valve 126a functions as a compressor outlet valve, similarly to compressor-outlet valve 92 of vehicle 88. Optionally, gas-turbine controller 128 also sets valve 124b to a closed state as schematically depicted in Figure 8C. As a result, valve 124b functions as a turbine inlet valve, as a heat-exchanger hot- stream valve, as a heat-exchanger cold-stream valve and as a combustor-flow valve, similarly to compressor-outlet valve 92 of vehicle 88.

When the supplying of fuel is suspended as described herein when gas -turbine 122 is operating according to an inverse-Brayton cycle as schematically depicted in Figure 8B, gas- turbine controller 128 concurrently sets valve 124a to an open state, as schematically depicted in Figure 8D. As a result, valve 124a functions as a compressor-inlet valve, similarly to compressor-inlet valve 116 of vehicle 110. Optionally, gas-turbine controller 128 also sets valve 126c to a closed state as schematically depicted in Figure 8D. As a result, valve 126c functions as a turbine inlet valve, as a heat-exchanger hot- stream valve, as a heat- exchanger cold-stream valve and as a combustor-flow valve, similarly to compressor- inlet valve 116 of vehicle 110.

In some embodiments of multipower gas-turbine 122, there is a separate compressor- inlet valve and/or compressor outlet valve used for reducing load on a compressor instead of valves 124 and/or 126 used for switching between the Brayton and inverse Brayton modes of operation.

In some embodiments, a gas-turbine is provided with valves, to reduce load on a compressor during at least part of the period of time during which supplying of fuel is suspended, in addition or instead of the valves discussed hereinabove with reference to the Figures. In some such embodiments, such valves are under control of a controller, analogously to the described above.

For example, in some embodiments, a gas-turbine comprises a turbine inlet valve to regulate air flow into the turbine when the compressor is rotating. In some such embodiments, a controller functionally associated with the gas-turbine is configured to set the turbine inlet valve to reduce (in some embodiments, substantially entirely block) air flow into the turbine during at least part of the time when the fuel supplying is suspended. In Figure 9A, a gas-turbine 60 configured for operation according to a Brayton-cycle with a turbine- inlet valve 130 is schematically depicted. In Figure 9B, a gas-turbine 114 configured for operation according to an inverse Brayton-cycle with a turbine-inlet valve 130 is schematically depicted.

For example, in some embodiments, a gas-turbine comprises a heat-exchange hot- stream valve to regulate air flow into the heat-exchanger hot-stream conduit when the compressor is rotating. In some such embodiments, a controller functionally associated with the gas-turbine is configured to set the heat-exchange hot- stream valve to reduce (in some embodiments, substantially entirely block) air flow through heat-exchange hot-stream valve during at least part of the time when the fuel supplying is suspended. In Figure 9A, a gas- turbine 60 configured for operation according to a Brayton-cycle with heat-exchange hot- stream valve 132 is schematically depicted. In Figure 9B, a gas-turbine 114 configured for operation according to an inverse Brayton-cycle with a heat-exchange hot- stream valve 132 is schematically depicted.

For example, in some embodiments, a gas-turbine comprises a heat-exchanger cold- stream valve to regulate air flow into the heat-exchanger cold- stream conduit when the compressor is rotating. In some such embodiments, a controller functionally associated with the gas-turbine is configured to set the heat-exchanger cold-stream valve to reduce (in some embodiments, substantially entirely block) air flow through heat-exchange cold-stream valve during at least part of the time when the fuel supplying is suspended. In Figure 9A, a gas- turbine 60 configured for operation according to a Brayton-cycle with a heat-exchanger cold- stream valve 134 is schematically depicted. In Figure 9B, a gas-turbine 114 configured for operation according to an inverse Brayton-cycle with a heat-exchanger cold-stream valve 134 is schematically depicted.

For example, in some embodiments, a gas-turbine comprises a combustor-flow valve to regulate air flow into the combustor when the compressor is rotating. In some such embodiments, a controller functionally associated with the gas-turbine is configured to set the combustor-flow valve to reduce (in some embodiments, substantially entirely block) air flow into the combustor during at least part of the time when the fuel supplying is suspended. In Figure 9A, a gas-turbine 60 configured for operation according to a Brayton-cycle with a combustor-flow valve 136 is schematically depicted. In Figure 9B, a gas-turbine 114 configured for operation according to an inverse Brayton-cycle with a combustor-flow valve 136 is schematically depicted.

In the specific embodiments discussed above with reference to the figures, a controller for implementing embodiments of the method described herein is depicted as a component of the gas-turbine controller. In some embodiments, not all but only some functions and/or parts thereof are part of a gas-turbine controller. In some embodiments, such a controller, or some functions and/or parts thereof are an independent unit. In some embodiments, such a controller, or some functions and/or parts thereof are part of a different component of a vehicle. For example, in some embodiments, such a controller, or some functions and/or parts thereof are part of a power management unit. In some embodiments, functions and/or parts of such a control are a part of two or more vehicular components, for example a gas-turbine controller and a power management unit.

The valves discussed above (e.g. , turbine inlet valve, compressor outlet valve, compressor inlet valve, heat-exchanger cold-stream valve, heat-exchanger hot-stream valve, combustor-flow valve) may be implemented using any suitable valve, for example valves such as described for use with gas-turbines in US 6,526,757.

In some embodiments, at least a portion of the combustor of a gas-turbine includes a coating that eases ignition. Suitable coatings include coatings described, for example, in US 4,603,547.

In the embodiments discussed above, once the supplying of fuel is suspended, rotation of the compressor and other gas-turbine components continues as a result of inertia and/or active rotation with no braking of the rotation. In some embodiments, there is some active braking of the rotation of the compressor.

It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination or as suitable in any other described embodiment of the invention. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements.

For example, embodiments of a hybrid gas-turbine electric vehicle or a gas-turbine include one or more of a compressor-rotating motor, a generator configured to function as a compressor-rotating motor, a turbine inlet valve, a compressor outlet valve, a compressor inlet valve, a turbine/compressor clutch, a gas-turbine/generator clutch, a heat-exchanger cold- stream valve, a heat-exchanger hot- stream valve and combustor-flow valve, in any suitable and practical combination.

For example, embodiments of a hybrid gas-turbine electric vehicle or a gas-turbine where the gas-turbine is configured to operate according to a Brayton cycle include one or more of a compressor-rotating motor, a generator configured to function as a compressor- rotating motor, a turbine inlet valve, a compressor outlet valve, a turbine/compressor clutch, a gas-turbine/generator clutch, a heat-exchanger cold-stream valve, a heat-exchanger hot- stream valve and combustor-flow valve, in any suitable and practical combination. For example, embodiments of a hybrid gas-turbine electric vehicle or a gas-turbine where the gas-turbine is configured to operate according to an inverse Brayton cycle include one or more of a compressor-rotating motor, a generator configured to function as a compressor-rotating motor, a turbine inlet valve, a compressor outlet valve, a compressor inlet valve, a turbine/compressor clutch, a gas-turbine/generator clutch, a heat-exchanger cold- stream valve, a heat-exchanger hot- stream valve and combustor-flow valve, in any suitable and practical combination.

For example, embodiments of a hybrid gas-turbine electric vehicle or a gas-turbine where the gas-turbine is a multipower gas-turbine include one or more of a compressor- rotating motor, a generator configured to function as a compressor-rotating motor, a turbine inlet valve, a compressor outlet valve, a compressor inlet valve, a turbine/compressor clutch, a gas-turbine/generator clutch, a heat-exchanger cold- stream valve, a heat-exchanger hot- stream valve and combustor-flow valve, in any suitable and practical combination.

Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.

Citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the invention.

Section headings are used herein to ease understanding of the specification and should not be construed as necessarily limiting.

Claims

WHAT IS CLAIMED IS:

1. A method of operating a hybrid gas-turbine electric vehicle including:

at least one gas-turbine with a combustor, a compressor and a turbine, said gas-turbine functionally associated with at least one generator; the method comprising:

supplying fuel to said combustor of said gas-turbine to maintain fuel combustion in said combustor;

suspending said supplying of fuel to said combustor, thereby stopping fuel combustion in said combustor;

allowing said compressor of said gas-turbine to rotate for a period of time during which supplying of fuel is suspended; and

prior to complete stopping of rotation of said compressor, resuming supplying fuel to said combustor and resuming fuel combustion in said combustor.

2. The method of claim 1, further comprising:

concurrently with said resumption of supplying of fuel to said combustor, igniting fuel, thereby resuming fuel combustion in said combustor.

3. The method of any of claims 1 to 2, further comprising:

during at least part of said period of time during which supplying of fuel is suspended, rotating said compressor.

4. The method of claim 3, the vehicle including a compressor-rotating motor functionally associated with said compressor, and said rotating of said compressor comprises activating said compressor-rotating motor.

5. The method of claim 9, wherein said compressor-rotating motor is substantially said generator operating as an electric motor.

6. The method of any of claims 1 to 5, further comprising during at least part of said period of time during which supplying of fuel is suspended, reducing load on said compressor.

7. A controller suitable for use with a gas-turbine, comprising:

a) a processor unit, configured to:

8. The controller of claim 7, wherein said fuel-resumption rules include possible resumption of the supplying of fuel to the combustor when a current speed of rotation of the compressor of the gas-turbine approaches a lower limit.

9. The controller of any of claims 7 to 8, configured to activate an ignitor to ignite fuel concurrently with said resumption of said fuel- supplying to resume combustion in a combustor of the gas-turbine

10. The controller of any of claims 7 to 9, wherein said fuel-resumption rules include possible resumption of the supplying of fuel when a current state of charge is below a minimum value.

11. The controller of any of claims 7 to 10, wherein said fuel- suspension rules include possible suspension of the supplying of fuel when a current state of charge of at least one storage component of a power storage unit is above a minimum value.

12. The controller of any of claims 7 to 11, wherein said fuel- suspension rules include possible suspension of the supplying of fuel when a regenerative braking unit generates more than a minimum amount of power.

13. The controller of any of claims 7 to 12, wherein said fuel-resumption rules include possible resumption of the supplying of fuel when a regenerative braking unit generates less than a minimum amount of power.

14. The controller of any of claims 7 to 13, wherein said fuel- suspension rules include possible suspension of the supplying of fuel when a vehicular drive motor requires less than minimum amount of power.

15. The controller of any of claims 7 to 14, wherein said fuel-resumption rules include possible resumption of the supplying of fuel when a vehicular drive motor requires more than a minimum amount of power.

16. The controller of any of claims 7 to 15, further configured to activate an additional vehicular component to reduce a load on a compressor of the gas-turbine during at least part of said period of time during which supplying of fuel is suspended.

17. The controller of any of claims 7 to 16, further configured to activate a motor to rotate the compressor of the gas-turbine during at least part of said period of time during which said supplying of fuel is suspended.

18. A hybrid gas-turbine electric vehicle, comprising:

a) a power management unit;

b) at least one electric drive motor for driving the vehicle using electric power provided by said power management unit;

c) at least one gas-turbine including a turbine, a combustor, a compressor and a fuel- supply unit, functionally associated with at least one generator to generate electric power from mechanical power produced by said gas-turbine, and to provide the generated power to said power management unit;

d) a chargeable power storage unit for storing electric power received from said power management unit and for releasing stored power to said power management unit; and

e) a controller configured to suspend the supplying of fuel to said combustor by said fuel-supply unit while said compressor is rotating.

19. The vehicle of claim 18, said controller further configured to resume a suspended supplying of fuel to said combustor by said fuel-supply unit while said compressor is rotating.

20. The vehicle of any of claims 18 to 19, further comprising an ignitor functionally associated with said combustor, wherein said controller is configured to automatically resume a suspended supplying of fuel to said combustor by said fuel- supply unit while said compressor is still rotating and to concurrently activate said ignitor to resume fuel combustion in said combustor.

21. The vehicle of any of claims 18 to 20, further comprising a compressor-rotating motor functionally associated with said compressor, configured to rotate said compressor during a period of time when said supplying of fuel is suspended.

22. The vehicle of claim 21, said controller configured to activate said compressor- rotating motor during at least part of said period of time when said supplying of fuel is suspended.

23. The vehicle of any of claims 18 to 22, said generator configured to rotate said compressor of said gas-turbine during at least part of said period time when said supplying of fuel is suspended.

24. The vehicle of claim 23, said controller configured to activate said generator to rotate said compressor during at least part of said period of time when said supplying of fuel is suspended.

25. A gas-turbine suitable for use in a gas-turbine hybrid electric vehicle, comprising: a) a turbine;

b) a combustor configured for combusting fuel with air and directing resulting exhaust to expand through said turbine;

c) a compressor for directing air from the surroundings to said combustor;

e) a fuel-supply unit configured to regulate the supplying of fuel to said combustor; and

f) a gas-turbine controller configured to suspend the supplying of fuel to said combustor by a fuel-supply unit while said compressor is rotating.

26. The gas-turbine of claim 25, said gas-turbine controller further configured to resume a suspended supplying of fuel to said combustor by said fuel-supply unit while said compressor is rotating.

27. The gas-turbine of any of claims 25 to 26, further comprising an ignitor functionally associated with said combustor, wherein said gas-turbine controller is configured to automatically resume a suspended supplying of fuel to said combustor by said fuel-supply unit while said compressor is still rotating and to concurrently activate said ignitor to resume fuel combustion in said combustor.

28. The gas-turbine of any of claims 25 to 27, further comprising a compressor-rotating motor functionally associated with said compressor, configured to rotate said compressor during a period of time when said supplying of fuel is suspended.

29. The gas-turbine of claim 28, said gas-turbine controller configured to activate said compressor-rotating motor during at least part of said period of time when said supplying of fuel is suspended.