GB2504656A

GB2504656A - Portable power generation apparatus

Info

Publication number: GB2504656A
Application number: GB1210393.3A
Authority: GB
Inventors: John Vaughan; David Smith; Mark Graham
Original assignee: Cosworth Ltd
Current assignee: Cosworth Ltd
Priority date: 2012-06-11
Filing date: 2012-06-11
Publication date: 2014-02-12
Also published as: GB201210393D0

Abstract

A portable power generation apparatus comprises a power unit (2, fig.4) for generating electrical power and a monocoque shell 3 for structurally supporting the power unit. Also provided is a monocoque 3 for a portable power generation apparatus which comprises at least one mount (14, fig.4) for attachment of a power unit, such as an engine, at least one fuel connector for attachment to an external supply of fuel and at least one electrical output terminal 20, 21 for electrically connecting the power unit to a device to be powered by the power generation apparatus. A preferred embodiment relates to a lightweight, portable, modular power generation system which may be stowed on and transported by a vehicle, wherein the dimensions of the power generation system are substantially the same as a fuel container, such as a jerry can, such that the generator is stowable in the space intended for stowing the fuel container.

Description

PORTABLE POWER GENERATION APPARATUS

FIELD OF THE INVENTION

The invention relates to a portable power generation apparatus. The apparatus is particularly suitable for use as an Auxiliary Power Unit (APU) for a vehicle such as a military vehicle to provide additional power for vehicle systems or to power external electrical devices.

The invention further relates to a rnonoèoque for a portable power generation apparatus.

BACKGROUND TO THE PRESENT INVENTION

A known type of generator includes a tubular frame which carries the structural loads of the power generating unit -typically an internal combustion engine -in an "open frame" arrangement. One example is the Honda EC2000 generator. This construction uses hollow pipes of varying diameters that are bent and welded to form an external frame. The engine is bolted the frame. In addition to providing support for the power unit, the tubular frame allows the generator to be carried by several people simultaneously and held from multiple angles and positions on the frame, In a modified form of this known type of generator, panels of varying materials are attached to the "open frame" to reduce noise and restrict access to hazardous components. Examples are the Honda EG5500 and Yamaha EF2800i generators. These panels are not load bearing; they are typically hung from the tubular chassis by fixings in the corners of or around the edge of the panels to enclose the generator thereby protecting the user and in some cases to improve the aesthetics of the unit.

A further type of known generator, particularly for larger (>3kw) generators, has a heavy structural base plate to bear the load of the engine, with a casing that completely encloses the generator. One example is the Honda EX4000 generator. The panel consists of a large sheet with two approximately 900 bends which forms a bridge over the engine and two end plates which can be secured to the bridge portion to complete the casing. The casing typically provides some noise reduction and operator protection and improves the aesthetics of the generator but does not bear any significant structural load, wheels may be provided to enable the generator to be moved.

The inventors of the present invention have appreciated that the known portable generator units described above tend to enclose significant additional volume that is not necessary for the functioning of the generator. Generator units are therefore often much larger and bulkier than is necessitated by the size of the apparatus for generating power. The known generators also often have relatively large wall thickness, for example resulting from the steel tubing of the open frame" designs, or the heavy gauge, structural base plate of other known designs. This increases the overall weight and external volume of the generator The inventors have appreciated that there is a need for an improved portable power generation apparatus which makes more efficient use of spaS so that the overall weight and external volume of the apparatus is minimised.

SUMMARY OF THE PRESENT INVENTION

Throughout this specification, the word "portable is used to refer to a power generating apparatus which is capable of being, and generally intended to be, moved from one location to another, to provide power when required. It is not intended to be limited to a power generating apparatus that is capable of being transported by a single person but also includes an apparatus which is portable by two or more people or by some other means, for example, on wheels or by a wheeled, or vehicle-based, lifting device such as a hoist or winch.

The invention in a first aspect provides: a portable power generation apparatus, comprising: a power unit for generating electrical power; and a monocoque for structurally supporting the power unit.

The monocoque shell of the present invention provides a dual function -it provides structural support for the power unit and also provides a means for encasing the power generating apparatus. In doing so, the monocoque combines the functions of two different elements of known generator designs -it combines the functions of: (i) the tubular steel chassis and additional panelling of the known open frame" type generators; or alternatively (ii) the load-supporting base plate and additional cover of the other types of known generators discussed above, The extra panelling that some generators have is therefore unnecessary due to the generator being enclosed by the monocoque itself. This leads to a reduction in the size and non-structural weight of the power generation apparatus making it easier to transport and store.

The monocoque provides an effective means for supporting the power unit in which the load of the power unit is effectively distributed across the entire monocoque structure, thereby providing a robust yet lightweight support structure. In encasing the generator, it also serves a number of additional purposes: rninimises noise transmission from the generator; protects the operator from the internal components of the generator; helps to protect the internal components of the generator from physical damage and from dust, water, sand and other contaminants, making it particularly suitable for use in a range of operating environments; improves the aesthetics of the generator.

The monocoque design of the present invention makes more efficient use of space thereby enabling the external volume of the apparatus to be minimised. Since the load of the poQer unit supported by the monocoque is distributed over the whole of the monocoque shell, the cross sectional thickness of the shell can be reduced compared to that of other known generator designs. It also means that the monocoque can be made from lightweight materials that are unlikely to be suitable for use in the known open frame and base plate designs.

The ability to attach components of the power generating apparatus at any point to the inside of the monocoque allows components to be placed more freely within the internal volume, resulting in a more efficient use of the available space and to tailor the layout of the internal components to a target storage space. This permits downsizing of the unit since the monocoque does not enclose as much unused volume.

The monocoque can conform more closely to the internal components of the power generation apparatus thereby minimising unoccupied internal volume and the overall size of the unit. The use of a monocoque also enables the power generation apparatus to be configured so as to have a particular external size and shape so that it can more easily be tailored to the available space in a given application.

Since the monocoque of the present invention fully encases the generator, it also offers the opportunity for excellent noise attenuation, especially from high frequency sound.

Furthermore, the monocoque allows integrated control of airflow over the internal components to aid cooling, whilst limiting the noise produced by their operation that is emitted to the environment. The potential for integration of cooling air guides into the monocoque structure also reduces part count.

Preferably, the portable power generation apparatus is a portable, auxiliary, power generation apparatus. It may be used to provide auxiliary power to supplement the power available from a primary power source, for example a vehicle engine. It may provide power to one or more or the same or different devices as those powered by the primary power source. The electrical power generated by the auxiliary power generation apparatus may be greater than the power available from the primary power source.

Preferably the portable power generation apparatus is a substantially self-contained power generation apparatus. It can therefore be quickly and easily operated to provide additional power.

Preferably, the monocoque substantially encloses the entire power generation apparatu& In doing so it protects the internal components from damage and contamination and prevents operator contact with the internal components, among other functions.

Preferably, the monocoque includes at least one mount for the power unit More preferably the at least one mount is integrally formed with the monocoque. The ability to attach components of the power generation apparatus at any point to the inside of the outer casing allows components to be positioned more freely within the internal volume, resulting in a more efficient use of the space available and the ability to tailor the layout of the internals to a specific shape. This arrangement advantage allows further downsizing of the unit since the monocoque does not enclose as much unused volume.

Preferably, the at least one integral mount includes a flexible, vibration-damping element.

This provides vibration damping to the power unit to reduce vibration and noise.

The monocoque may be formed in two or more monocoque sections removeably attachable by one or more fixing means. This enables the monocoque to be formed, for example pressed, machined from a billet of material or cast in separate sections to which the power unit is attached and the sections can be joined together to encapsulate the power unit. The monocoque sections may be hinged along a side forming a fold-out monocoque structure for easy access to components. The sections may be held together with quick release fasteners such as catches or latches to facilitate separation of the sections.

Preferably the monocoque defines at least one integral channel or passage for cooling air.

The passages for cooling air may be defined by air directing features such as vanes or channels integral with the monocoque. This reduces the number of separate components required for the power generation apparatus which can lead to a further reduction in the overall size of the apparatus.

Preferably, at least one cooling fan is contained within the monocoque for drawing cooling air through a hole in the monocoque into an internal cavity of the monocoque. This provides air circulation over the power generation components to improve cooling.

Preferably the generator includes at least one surface mounted power output terminaL This allows the generator to be quickly and easily electrically coupled to a device requiring power.

The terminal may for example be a conventional electrical connector to enable the generator to be quickly and easily connected when required.

Preferably the generator includes a layer of Sound proofing material secured to inside surface of the monocoque. More preferably the sound proofing material is melamine acoustic foam.

This helps to control the noise emitted by the apparatus. It also provides thermal insulation.

Preferably there is a means coupled to the monocoque for transporting the power generation apparatus. Preferably, the means for transporting the power generation apparatus is at least one carrying handle. More preferably, the carrying handle is a self-retractable, fold-out, or slide-out, carrying handle. This enables the power generation apparatus to be repositioned, the load of the power generation apparatus being transmitted through the monocoque to the handle.

Preferably, the generator is configured for use on board a vehicle. More preferably, the external shape and dimensions of the monocoque are such that it stowable in a defined compartment on the vehicle. More preferably, the external shape and dimensions of the monocoque are substantially the same as a portable fuel container such that the generator is stowable in the space on a vehicle intended for stowage of a portable fuel container. This advantageously enables the generator to be stored in a compartment intended for a fuel container, such as a Jerry Can on a vehicle, for example a military vehicle without any reconfiguration of the vehicle. Preferably, the external shape and-dimensions of the monocoque are substantially the same as 20 litre Jerry Can so that it can easily be stowed on a vehicle designed to carry such equipment.

Preferably, the power unit is an internal combustion engine. More preferably, the power unit is a compression ignition engine. More preferably, the power unit is a 2-stroke, compression ignition, engine. Lightweight heavy fuel engines such as those developed for Unmanned Air Vehicles are particularly suitable for use in the power generation apparatus.

The invention in a second aspect provides a monocoque for a portable power generation apparatus, comprising: at least one mount for attachment of a power unit; at least one fuel connector for attachment to an external supply of fuel; and at least one electrical terminal for electrically connecting the power unit to a device to be powered by the power generation apparatus.

Preferred features of the monocoque are set out in the dependent claims to which reference should now be made.

BRIEF DESCRIPTION OF THE FIGURES

Preferred embodiments of the present invention will now be described, by way of example only, with reference to the accompanying figures, in which:

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Figure 1 shows an isometric view of a portable power generation apparatus according to a first aspect of the present invention; Figure 2 shows a top view of the portable power generation apparatus of Figure 1; Figure 3 shows a bottom view of the portable power generation apparatus of Figure 1; Figure 4 shows the portable power generation apparatus of Figure 1 with the monocoque shell removed: Figure 5 shows a top view of the portable power generation apparatus of Figure 4; Figure 6 shows a bottom view of the portable power generation apparatus of Figure 4; Figure 7 shows an isometric view of a monocoque according to a second aspect of the present invention with the internal power generation apparatus removed; Figure 8 shows a front view of the monocoque of Figure 7; Figure 9 shows a rear view of the monocoque of Figure 7; Figure 10 shows a side view of the monocoque of Figure 7 Figure 11 shows a further side view of the monocoque of Figure 7 Figure 12 shows a section along the line A-Aof Figure 9; Figure 13 shows a section along the line B-B of Figure 11; and Figure 14 shows a section along the line C-C of Figure 8

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

Figures 1 to 6 show an example portable generator assembly 1 comprising a power unit 2 for generating electrical power and a monocoque 3 for structurally supporting the power unit.

The generator is a substantially self-contained, stand alone unit.

As described further below, the generator is particularly suitable for use as an Auxiliary Power Unit (APU) to be carried by a military vehicle and operated to provide supplementary power for onboard vehicle systems or electrical devices, such as communications equipment, satellite receivers, computers, weapon systems and environmental controls. This reduces the electrical burden of these devices on the vehicle's electrical system.

The power unit is an internal combustion engine for generating mechanical energy. A suitable engine is a lightweight 2-stroke compression ignition engine such as those used on Unmanned Air Vehicles (UAVs). Such engines are typically single cylinder engines or two cylinder engines, which may be arranged in a flat, boxer' configuration or in a V configuration. The engine preferably has a power output of 5 to 10kW although engines having a greater power output may also be used. A particularly suitable engine is the Lightweight Compact Diesel Engine of the Applicant's own earlier United Kingdom patent no. GB 2,428,741 or the improved lightweight two stroke compression ignition engine which is the subject of another United Kingdom patent application filed by the Applicant on the same day as the present application under the title "Controllable Fuel Injection System for a Two-Stroke Compression Ignition Engine". An advantage of the latter engine is that it can be run on diesel or heavy fuels of variable or unknown fuel grade. This makes the generator particularly suitable for military applications and use in remote environments where the supply of fuel is limited and fuel of a particular grade, for example one having a particular Cetane Number.

The monocoque, which is described further below, forms a rigid outer casing or shell which provides support for the power unit and a means for encasing the power unit and other components of the power generation apparatus. It protects the operator from the internal components of the generator, helps to protect the generator components from physical damage and contaminants and improves the aesthetics of the generator.

The monocoque may fully or partially enclose some or all of the following components of power generator apparatus, among others (see Figures 4-6): * an alternator 4 driven by the output shaft of the engine for converting the mechanical energy generated by the engine to electrical energy; * on or more power electronics modules 25 which may be fitted with a heat sink to provide improved cooling: * an engine specific Electronic Control Unit (ECU) 5 for controlling the engine which may be fitted with a heat sink to provide improved cooling; * a generator set Electronic Control Unit (ECU) for controlling the alternator; * a fuel pump 6 for supplying the engine with fuel; * an oil pump 7 for supplying lubricating oil for lubricating the moving parts of the engine; * an oil tank 8 from which the oil pump draws oil; * a cooling fan 9 for drawing external air into the monocoque for cooling the engine and other power generation components; - * a cooling air duct/channel/cowl 10 for channelling the cooling air through the monocoque; * an air filter 11 for filtering air prior to induction; * an exhaust pipe 12 for removing the waste products of combustion from the engine leading to a silencer 13.

Some components, for example the engine specific ECU 5, the air intake filter 11 and the exhaust 12 are preferably partially enclosed by the monocoque and partially exposed to facilitate access for maintenance or control of the apparatus or to improve cooling. As shown in the Figures, all of the generator components are preferably within the overall envelope of the monocoque.

Some of these generator components are generally known in the art and will not be further described in detail. Others are described in more detail below.

As the load of the power unit and other components attachable to the monocoque is distributed substantially over the whole of the monocoque, the monocoque can be made from lightweight materials. Preferably, the monocoque is cast from Aluminium. Alternatively, it may be pressed from sheet aluminium or machined from a solid Aluminium billet. Alternative materials, for example other metals, polymers, plastics and composites. may be alternatively be used for reasons of cost, weight and durability and to provide heat resistance and noise reduction. Other suitable materials and manufacturing processes may also be used and will be apparent to the skilled person.

The monocoque includes one or more engine mounting points. The mounting points are integrally formed with the monocoque and may include integral ribs or webs for additional stiffness and support. The mounts may be threaded bushings for receiving fixing means for securing the engine to the monocoque. The engine is secured to the mounting points using flexible or anti-vibration mounts to reduce the transmission of engine vibration to the shell (see Figures 4,5,14). The engine mounts 14 may include a rubber block or spring or other type of resilient element. A bracing bar 26 (Figure 14) may also be provided to improve the stiffness of the monocoque in the region of the engine mounts.

Other components of the power generation apparatus, such as those listed above, can be either attached to the monocoque directly or attached to the engine which is supported by the monocoque. Components attached to the monocoque are preferably attached using anti-vibration mounts for vibration isolation.

The engine may be provided with a single, common exhaust pipe 12 or one exhaust pipe per cylinder. The, or each, exhaust pipe begins within the monocoque. The pipe does not leave the envelope of the monocoque shell, but one or more holes 15 in the monocoque may be provided to allow the pipe to extend to the full limit of the design envelope and to dissipate heat externally and away from other components of the generator. A flexible element in the exhaust pipe allows for relative movement and thermal expansion.

The monocoque includes one or more arrays 16 of holes or slots for permitting air to pass through the shell and into the internal cavity. The monocoque may include one or more removable panels 17 for permitting access to components of the power generation apparatus.

The panels also permit adjustment or reconfiguration of the monocoque. For example, a panel with an array of holes or slots to permit ingress of cooling air can be replaced with a blanking panel when the generator is used in cooler environments where the need for cooling may be reduced.

The central hub 18 of each cooling fan 9 forms a relatively large part of the fan diameter to reduce the area through which noise can escape from the monocoque. The number of blades on the fans are different to the number of spokes to prevent multiple simultaneous blade/spoke interactions during fan rotation. The spokes are curved to prevent the entire length of the blade interacting with each spoke simultaneously.

Each fan is fitted with an air directing cowl 10. The cowl has a central partition that splits the airflow leaving the fan into two streams, with one stream directed through the cooling fins on one or more cylinders of the engine and the other stream is directed through the cooling fins on the barrel of one or more cylinders. Cooling air passing over the cylinders is vented through the holes or slots through the monocoque to dissipate heat to the surrounding air.

At least a portion of the inside surface of the monocoque is lined with a layer of melamine acoustic foam 19 for minimising the noise emitted from the shell and for providing heat insulation. The foam is secured to the monocoque with an adhesive. Polyurethane foam or polyester fibres may alternatively be used for insulation. Other suitable insulating materials and techniques will also be apparent.

The monocoque has a pair of output terminals 20, 21 for electrically connectng the power generation apparatus to a one or more external devices requiring electrical power or to a means for distributing power to a number of devices. The terminals are surface mounted to facilitate coupling of the power generation apparatus to external devices, The terminals may include on or more known types of electrical connectors allowing quick and simple connection of the generator to a vehicle or other devices requiring power.

The monocoque has a pair of carrying handles 22, 23, each comprising a gripping portion extending between a pair of arms. The handles are self-retracting and can be pulled out or folded out from the monocoque to allow the generator to be moved. One suitable handle is normally flush with the surface of the monocoque and rotatable about a hinge to an extended position for carrying the generator. When the handle is released, a torsion spring attached to the hinge returns the handle from the extended position to the original position, flush with the surface. Another suitable handle is normally flush with the surface of the monocoque and the handle arms are longitudinally slidable or extendable from slots or channels in the monocoque. When the handle is released, compression springs within the monocoque act on the ends of the handle arms to withdraw the handle into the monocoque until the gripping portion is flush with the surface. The monocoque may comprise one or more of the same handle or a combination of different types of handle.

The monocoque stands on four anti-vibration feet! pads or strips 24 which to minimise the transmission of vibration to the surface on which the generator is supported. These may be made from rubber or another suitable resilient material.

The monocoque can alternatively be formed in two or more sections which are individually cast, moulded, pressed or otherwise machined. The monocoque sections are releasably attachable with fasteners to permit disassembly of the monocoque to allow access to the internal components for maintenance or replacement, and reassembly to form a monocoque shell. The sections may be hinged along a side to provide a fold-out monocoque structure.

Suitable fasteners include nuts and bolts or quick release fasteners such as latches and locking pins to facilitate access. The engine and associated components may be secured to one or both monocoque sections as required to provide access when the monocoque sections are separated or folded open.

In addition to the components of the power generation apparatus listed above, if there is sufficient available space for the generator, the monocoque may also include a fuel tank from which the fuel pump draws fuel to supply the engine. Alternatively, the monocoque may be provided with a surface mounted fuel connector which may be a quick release pipe connector for connecting to fuel tank external to the monocoque.

In a particularly preferred embodiment, the monocoque encasing the generator forms a substantially self contained, stand-alone generator unit for generating power having a surface mounted fuel connector for attachment to an external fuel supply, which may be feed from a vehicle's fuel tank, a portable fuel container or another fuel supply, and a pair of electrical terminals for connection to one or more systems or devices requiring power.

As shown in the figures, in a particular preferred embodiment, a generator according to the invention forms an Auxiliary Power Unit (APt.)) for a vehicle which can be operated on board the vehicle or on the ground adjacent the vehicle to provide auxiliary power. The external shape and dimensions of the monocoque are substantially the same as a conventional, portable, fuel container, such as an 18 or 20 Litre Jerry Can which is designed to be stowed on and transported by a vehicle, for example a military vehicle, and used to refill the vehicle's fuel tank as required. The APU may alternatively have substantially the same shape and dimension as a water tank or other portable container designed to be carried by a vehicle.

This enables the generator to be stored in the space on a vehicle designed to stow a Jerry Can or other type of container, enabling the generator to be transported without modification to the vehicle structure. Most preferably, the generator unit has the shape and dimensions of a 20 litre Jerry Can. The fuel and electrical connectors are positioned at a point on the monocoque which enables it to be connected and operated on the vehicle in the stowed position. A vehicle may be loaded with one or more such jerry can sized generators and jerry cans filled with fuel in accordance with the expected requirement for fuel and auxiliary power in a particular environment or on a particular journey.

It will be appreciated that the generator may have an alternative shape and can be configured in accordance with the size and weight restrictions and the available space for a given application.

As the monocoque structure provides load-bearing strength in all directions, the generator may be configured to be stored and operated in multiple orientations. This may require a modified oil tank breather system Raising the generator from the supporting surface, for example using anti-vibration feet on all sides, allows outlet air to escape when the generator is operated in any orientation.

In addition to the vehicle APU application discussed above, the generator of the present invention is also suitable for use in other applications requiring a small, lightweight generator, for example: garden machinery such as chainsaws, lawnmowers, strimmers, hedge trimmers, leafblowers etc., industrial machine tools such as grinders, saws and pumps and generators for domestic use.

It is envisaged that the monocoque also has other applications besides encasing a combustion engine. The monocoque could for example be: used to provide structural support for a fold-out fuel cell and associated power generating apparatus; configured so that one or more surfaces is formed of a load bearing solar panel; or used as a floating monocoque with a mechanism capable of converting wave power to electrical, which may use gyroscope-based technology. It could also be used to form a substantially stand-alone portable pump for pumping water or other materials.

Claims

CLAIMS1. A portable power generation apparatus, comprising: a power unit for generating electrical power; and a monocoque for structurally supporting the power unit.
2. A portable power generation apparatus according to claim 1, wherein the power generation apparatus is a portable, auxiliary, power generation apparatus
3. A portable power generation apparatus according to claim 1 or 2, wherein the power generation apparatus is a substantially self-contained auxiliary power generation apparatus.
4. A portable power generation apparatus according to and of claims 1 to 3, wherein the monocoque substantially encloses the entire power generation apparatus.
5. A portable power generation apparatus according to any preceding claim, wherein the monocoque includes at least one integral mount for the power unit.
6. A portable power generation apparatus according to claim 5 wherein the at least one integral mount includes a flexible, vibration-damping element.
7. A portable power generation apparatus according to any preceding claim, wherein the monocoque is formed in two or more monocoque sections removeably attachable by one or more fixing means.
8. A portable power generation apparatus according to claim 7, wherein the monocoque sections are hinged along a side forming a fold-out monocoque structure.
9. A portable power generation apparatus according to any preceding claim, wherein the monocoque defines at least one integral channel or passage for cooling air.
10. A portable power generation apparatus according to any preceding claim including at least one cooling fan contained within the monocoque for drawing cooling air through a hole in the monocoque into an internal cavity of the monocoque. -
11. A portable power generation apparatus according to any preceding claim including at least one surface mounted power output terminal.
12. A portable power generation apparatus according to any preceding claim including a layer of sound proofing material secured to inside surface of the monocoque. -1213. A portable power generation apparatus according to claim 12 wherein the sound proofing material is melamine acoustic foam.14. A portable power generation apparatus according to any preceding claim including means coupled to the monocoque for transporting the power generation apparatus.15. A portable power generation apparatus according to claim 14 wherein the means for transporting the power generation apparatus is at least one carrying handle.16. A portable power generation apparatus according to claim 15 wherein the carrying handle is a self-retractable, fold-out, or slide-out, carrying handle.17. A portable power generation apparatus according to any preceding claim configured for use on board a vehicle.18. A portable power generation apparatus according to claim 17 wherein the external shape and dimensions of the monocoque are such that it stowable ma defined compartment on the vehicle.19. A portable power generation apparatus according to claim 18 wherein the external shape and dimensions of the monocoque are substantially the same as a portable fuel container such that the generator is stowable in the space on a vehicle intended for stowage of a portable fuel container.20. A portable power generation apparatus according to claim 19 wherein the external shape and dimensions of the monocoque are substantially the same as 20 litre Jerry Can 21 A portable power generation apparatus according to any preceding claim wherein the power unit is an internal combustion engine.22. A portable power generation apparatus according to claim 21 wherein the power unit is a compression ignition engine.23. A portable power generation apparatus according to claim 22 wherein the power unit is a 2-stroke, compression ignition, engine.24. A vehicle including a portable power generation apparatus according to any of the preceding claims.25. A monocoque for a portable power generation apparatus, comprising: at least one mount for attachment of a power unit; at least one fuel connector for attachment to an external supply of fuel; and at least one electrical terminal for electrically connecting the power unit to a device to be powered by the power generation apparatus.26. A monocoque according to claim 25, wherein the fuel connector is a surface mounted fuel connector.27 A monocoque according to claim 26, comprising two surface mounted electrical connectors for electrically connecting the power unit to a device to be powered by the power generation apparatus.28. A monocoque according to claim 27, comprising two or more monocoque forming sections the monocoque sections being removably attachable by one or more attachment means to form a monocoque structure.29. A monocoque according to claim 28, wherein the monocoque forming sections are hinged along a sEde to form a fold-out monocoque structure.30. A portable power generation apparatus substantially as hereinbefore described with reference to the accompanying figures.31. A monocoque for a portable power generation apparatus substantially as hereinbefore described with reference to the accompanying figures. 14*