GB2571516A

GB2571516A - Device for generating electrical energy

Info

Publication number: GB2571516A
Application number: GB1801600.6A
Authority: GB
Inventors: Mckenzie Dale
Original assignee: Individual
Current assignee: Individual
Priority date: 2018-01-31
Filing date: 2018-01-31
Publication date: 2019-09-04
Also published as: GB201801600D0

Abstract

A device 2 for generating electrical energy comprises a body 4, eg of magnesium alloy or ceramic matrix composite (CMC), having at least one piston chamber 16 along which a first piston 18 and a second piston 20 travel in opposite directions. The device may be a two-stroke i.c. engine. At least one electrical generator 8a, 8b, 8c, 8d is coupled to the first piston 18 and/or the second piston 20 such that motion of the first piston 18 and/or the second piston 20 drives the electrical generator 8a, 8b, 8c, 8d. The first and seconds pistons 18, 20 may be coupled to respective crankshafts 28 and 32. Each generator 8a-8d may be a direct-drive brushless generator. The generator outputs may be connected to energy storage units eg capacitors or batteries. Each piston 18, 20 may have a magnetic element or material to generate a potential difference in a respective induction coil. The fuel may be eg hydrogen, methane, propane or butane.

Description

This invention relates to a device for generating electrical energy.

Background

Generator units comprising an electrical generator powered by internal combustion engines are well-known and widely used. One common application for such generator units is in diesel-electric engines. Such diesel-electric engines are commonly used in trains but are also used in heavy mining vehicles and in certain naval applications (e.g. to provide submarine propulsion). Another application for such generator units is backup electrical power generation to provide an electrical power supply in the event of electrical distribution system failure. A further application is in certain hybrid vehicles comprising an electrically driven drive-train powered by a battery. In such vehicles the generator unit is used to generate electricity to charge the battery.

Given that such generators comprise both an internal combustion engine and an electrical generator, for the amount of energy produced they are typically heavy and occupy a large volume.

It is an aim of certain embodiments of the invention to address such drawbacks.

Summary of the Invention

According to a first aspect of the invention there is provided a device for generating electrical energy comprising a device body having at least one piston chamber which defines a piston chamber axis; a first piston disposed within the piston chamber and arranged to travel along at least a portion of the piston chamber; a second piston disposed within the piston chamber and arrange to travel along at least a portion of the piston chamber, wherein the first piston and the second piston are arranged to be driven in opposite directions along the piston chamber axis; and at least one electrical generator coupled to at least one of the first piston and the second piston such that motion of the first piston and/or the second piston drives the electrical generator.

The device provides a compact and lightweight device for generating electrical energy. The device is therefore easy to transport and is suitable for use in many applications requiring the generation of electricity. The device can be advantageously used in many settings including light, medium or heavy automotive applications and for power generation in light, medium and heavy industrial applications.

The electrical generator may be a rotary electrical generator configured to operate at rotational speeds in excess of 10,000 rpm. In certain embodiments, an optimum RPM may be determined which provides optimised power output for optimised fuel consumption.

Electrical energy output (which may also be referred to as electrical power output) may be generated directly from the reciprocating motions of the pistons, for example via respective crankshafts, without intermediate gearing. In the case where the electrical generator is a rotary electrical generator, the rotary generator may have an input shaft which is driven at a 1:1 ratio with the piston(s) power cycles. That is to say, each complete reciprocating power cycle of the pistons produces a single rotation of the input shaft.

Optionally, the electrical generator is a first electrical generator coupled to the first piston and the device further comprises a second electrical generator coupled to the second piston. This coupling can be via any suitable means, for example a quill-shaft coupling or spline-shaft coupling.

Coupling the first piston and the second piston to respective generators can eliminate the need for mechanically coupling the first and second pistons together to extract power (for example by a transmission/gearing arrangement). This reduces frictional losses, heat generation and complexity and so enables each piston to reciprocate at a much greater rate. Thus, an output shaft connected to each the first piston can be operated at much higher rotation speeds than would otherwise be feasible. Typically, the first and second pistons are connected for timing purposes.

Optionally, the or each electrical generator comprises at least one direct drive generator, for example a direct-drive self-excited brushless generator. The use of a direct drive self-excited brushless generator eliminates the need for gearing arrangements between the piston(s) and associated crankshafts and the generator.

Optionally, the first and second pistons are arranged to define a single combustion chamber between the first piston, the second piston and a wall of the piston chamber. The pistons therefore move away from each other during an expansion stroke and towards each other during a compression stroke. Such an arrangement eliminates the need for a separate ‘cylinder head’ for each piston (i.e. use of an end of a piston chamber to define art of a combustion chamber). The device is therefore compact and has a beneficial power to volume ratio compared with other known arrangements.

Optionally, the first and second pistons are arranged to be driven synchronously.

Optionally, the piston chamber is provided with at least one fuel intake port and at least one exhaust port.

Optionally, the fuel intake port is arranged to introduce fuel into a central region of the piston chamber.

Optionally, the exhaust port is arranged to exhaust gases from a central region of the piston chamber.

Optionally, the device is configured to have a power cycle comprising only two strokes consisting of a single compression stroke in which a mixture of air and fuel is compressed within the piston chamber and a single expansion stroke in which the air and fuel is combusted, exhausted and further air and fuel is introduced to the piston chamber for subsequent combustion. In particular, the device may be configured to operate as a two-stroke internal combustion engine.

Optionally, the piston chamber is provided with an ignition element arranged to initiate combustion of fuel within the piston chamber. Optionally, the ignition element is arranged to initiate combustion of fuel within the piston chamber at the beginning of an expansion stroke of the piston. The ignition element may be a glow plug or spark plug or other suitable means.

In certain embodiments, the ignition element is provided by a spark ring, typically positioned at a mid-point of the piston chamber.

Optionally, at least one of the first piston and the second piston comprises a magnetic element or a magnetizable element. Optionally, the magnetizable element is a ferrous element for generating a magnetic field when current is induced in the ferrous element.

Optionally the magnetic or magnetizable element is an electromagnetic induction ring.

Optionally, said magnetic element or magnetizable element is arranged to produce a force at the beginning of an expansion stroke in the direction of travel of said piston. The device may be configured such that the repulsive force is generated periodically for a predefined period of time that may coincide with or immediately follow a combustion event within the piston chamber.

Optionally, the device further comprises at least one auxiliary electrical generator comprising at least one coil of electromagnetic material which extends around an end of the piston chamber and is arranged such that motion of said magnetic element or magnetizable element induces a potential difference and/or current in the electrical generator. In embodiments in which the first piston and the second piston each have a magnetic or magnetizable element, a respective coil may be provided at each end of the piston chamber.

Optionally, the coil is arranged such that said magnetic element or magnetizable element enters at least part of the coil at least once during each power cycle of the device thereby inducing a voltage and/or current within the coil.

Optionally, the device comprises a plurality of piston chambers, wherein a first piston and a second piston are disposed within each of the plurality of piston chambers and arranged to travel along at least a portion of the respective piston chambers and are arranged to be driven in opposite directions.

Optionally, the first pistons are coupled to a common first crankshaft which may be coupled to at least a first electrical generator. Optionally, the second pistons are coupled to a common second crankshaft which may be coupled to at least a second electrical generator.

Optionally, the first crankshaft is further coupled to a third electrical generator.

Optionally, the second crankshaft is further coupled to a fourth electrical generator.

Optionally, the device is configured to operate using liquid hydrogen as a fuel.

Optionally, the device comprises a cooling arrangement arranged to cool at least the device body. Optionally, the cooling arrangement comprises a gas refrigeration cooling system.

According to a second aspect of the invention there is provided an apparatus comprising a device in accordance with the first aspect of the invention, wherein an output of the at least one electrical generator is coupled to an energy storage device.

Optionally, the energy storage device comprises an electrical energy storage device and may include at least one of a battery or a capacitor or a condenser or other suitable device for temporarily storing energy.

According to a third aspect of the invention there is provided an automotive vehicle comprising: an electrical propulsion system; an energy storage unit; and a device in accordance with the first aspect of the invention, wherein the device is coupled to the energy storage unit such that electrical energy generated by the device is stored by 10 the energy storage unit.

Various further features and aspects of the invention are defined in the claims.

Brief Description of the Drawings

Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings where like parts are provided with corresponding reference numerals and in which:

Figure 1 shows a device for generating electrical energy;

Figure 2 is a side view of the device shown in Figure 1;

Figure 3 is an end view of the device shown in Figure 1;

Figure 4 is a top view of the device shown in Figure 1;

Figure 5 is sectional view of the device shown in Figure 1 along A-A as shown in Figure 15 4; and

Figure 6 corresponds to Figure 3 and shows internal components of the device.

Detailed Description

Figures 1 to 6 show a device 2 for generating electrical energy from a fuel such as liquid hydrogen. The device 2 comprises a device body 4 which defines first, second, third and fourth piston locating portions 6a, 6b, 6c, 6d. The device 2 further comprises first, second, third and fourth electrical generators 8a, 8b, 8c, 8d. The device body 4 is formed by an engine block section 10 and two end caps 12, 14.

The device body 4 may be made from a magnesium alloy such as AJ62A or may be made from a ceramic matrix composite (CMC) such as carbon-infused zirconia. The device body 4 may comprise a carbon ceramic, such as a low friction high heat resistant carbon ceramic. The device body 4 may, for example, comprise a carbon ceramic enhanced with graphene or other strengthening/conducting/insulating hybrid composite materials such as aerospace grade alloys or graphene composite copper wire ceramic matrix composites.

Figure 5 is a sectional view through the device 2 along A-A of Figure 4 in the region of the second piston locating portion 6b. The first, third and fourth piston locating portions 6a, 6c, 6d and the components within them are the same, or else substantially the same, as the second piston locating portion 6b unless stated otherwise.

In the region of the second piston locating portion 6b, the device body 4 defines a piston chamber 16 which extends vertically (as viewed in Figure 1) with respect to the top and bottom of the device 2. That is, the piston chamber 16 extends in a direction which is parallel with the direction from the first end cap 12 to the second end cap 14. The piston chamber 16 is cylindrical and defines a piston chamber axis X. First and second pistons 18, 20 are disposed within the piston chamber 16 and are arranged to travel (i.e. move) along the respective portion of the piston chamber 16 within which each piston 18, 20 is located. The pistons 18, 20 are arranged in an opposed relationship within the piston chamber 16 so as to define a combustion chamber between end faces 19, 21 of the pistons 18, 20 and the side wall defining the piston chamber 16.

A benefit of the arrangement is that, since each piston 18, 20 forms an end of a combustion chamber and only a single combustion chamber is required, a compact (which may be considered to be low volume) and relatively lightweight device 4 can be realised.

A first intake port 22a is provided through a sidewall of the piston chamber 16 and a second intake port 22b is provided through a sidewall of the piston chamber 16 opposite the first intake port 22a. An exhaust port 24a is also provided through a sidewall of the piston chamber 16 and a second exhaust port 24b is provided through a sidewall of the piston chamber 16. The first and second exhaust ports 24a, 24b are offset along the piston chamber axis X in opposite directions with respect to the respective first and second intake ports 22a, 22b towards the respective ends of the piston chamber 16. In the described embodiment, the first intake port 22a and the first exhaust port 24a are adjacent each other, and the second intake port 22b and the second exhaust port 24b are also adjacent each other. The intake ports 22a, 22b may be fitted with injector valves configured to atomise the liquid hydrogen or a liquid hydrogen and air mixture.

The first piston 18 is coupled via a connecting rod 26 to a first crankshaft 28 such that linear reciprocating motion of the first piston 18 along the piston chamber 16 is converted into rotary motion of the first crankshaft 28. Similarly, the second piston 20 is coupled via a connecting rod 30 to a second crankshaft 32 such that linear reciprocating motion of the second piston 20 along the piston chamber 16 is converted into rotary motion of the second crankshaft 32. The rotational axis Y of the first crankshaft 28 and the rotational axis Z of the second crankshaft 32 extend perpendicularly with respect to the piston chamber axis X.

Each of the other first, third and fourth piston locating portions 6a, 6c, 6d each have a respective piston chamber within which are disposed respective opposed first and second pistons, together with associated first and second connecting rods, and which are arranged in the same, or else substantially the same, manner as the pistons 18, 20 and connecting rods 26, 30 within the piston chamber 16 of the second piston locating portion 6b.

The first crankshaft 28 extends through all of the first, second, third and fourth piston locating portions 6a, 6b, 6c, 6d and the ends of the first crankshaft 28 protrude, respectively, from each end of the device body 4. The first pistons located in each of the first, third and fourth piston locating portions 6a, 6c, 6d are coupled to the first crankshaft 28.

The second crankshaft 32 extends through all of the first, second, third and fourth piston locating portions 6a, 6b, 6c, 6d and the ends of the second crankshaft 32 protrude, respectively, from each end of the device body 4. The second pistons located in each of the first, third and fourth piston locating portions 6a, 6c, 6d are coupled to the second crankshaft 32.

The first electrical generator 8a is coupled to one end of the first crankshaft 28 and the third electrical generator 8c is coupled to the other end of the first crankshaft 28.

The second electrical generator 8b is coupled to one end of the second crankshaft 32 and the fourth electrical generator 8d is coupled to the other end of the second crankshaft 32. Any suitable coupling known in the art can be used to connect the crankshaft ends to the electrical generators. For example, in certain embodiments, a quill-shaft coupling is used. In other embodiments, a spline-type coupling is used.

Thus, the first pistons associated with each of the respective first, second, third and fourth piston locating portions 6a, 6b, 6c, 6d are arranged to drive the first and third electrical generators 8a, 8c in unison via the first crankshaft 28. And the second pistons associated with each of the first, second, third and fourth piston locating portions 6a, 6b, 6c, 6d are arranged to drive the second and fourth electrical generators 8b, 8d in unison via the second crankshaft 32.

Each generator 8a, 8b, 8c, 8d comprises a direct-drive brushless generator. In particular, each generator comprises a direct-drive brushless generator comprising high-capacity copper windings.

The output of each generator 8a, 8b, 8c, 8d may be connected to an energy storage unit such as an energy storage unit for a vehicle. Suitable energy storage units include a battery or a capacitor or a condenser unit. The output of each generator 8a, 8b, 8c, 8d may also, or alternatively, be connected for immediate use (for example by an electric motor) and/or may be output to a transformer. Transfer of electrical power from the electrical generators 8a, 8b, 8c, 8d may be made using graphene composite copper wire which is relatively lightweight and capable of high voltage/current transfer. Operation of the device will now be described with reference to Figure 5 and the piston arrangement located in the second piston locating portion 6b, but it will be appreciated that the piston arrangements in the other first, third and fourth piston locating portions 6a, 6c, 6d operate in the same manner.

In operation, the device 2 operates as a two-stroke internal combustion engine. The device is intended to be multi-fuel and so capable of using liquid or gas hydrogen or diesel or any gas fuel which may be compressed in liquid form. Further examples include methane, propane or butane.

In the embodiment shown, the device 2 is configured to use, for example, liquid hydrogen.

The device 2 has a repeating power cycle which comprises two strokes: a compression stroke and an expansion (combustion) stroke.

At the beginning of the compression stroke, the first and second pistons 18, 20 are disposed at opposite ends of the piston chamber 16 so that each piston 18, 20 is at its closest point to the rotational axis Y, Z of the crankshaft 28, 32 to which it is connected. During the compression stroke, the first and second pistons 18, 20 move towards each other thereby expelling exhaust gases from the piston chamber 16 through the exhaust ports 24a, 24b. At the same time (contemporaneously), a mixture of fuel (e.g. liquid hydrogen) and air (comprising oxygen) is injected into the piston chamber 16 through the intake ports 22a, 22b. As the first piston 18 draws level with the first exhaust port 22a and the second piston 20 draws level with the second exhaust port 22b, the first piston 18 seals the first exhaust port 22a and the second piston 20 seals the second exhaust port 22b.

The end of the compression stroke is defined as when each piston 18, 20 has reached its furthest distance of travel away from the axis of rotation Y, Z of the crankshaft 28, 32 to which it is attached. The expansion stroke commences with ignition of the mixture of fuel and air within the piston chamber 16. Ignition may occur spontaneously as a consequence of the temperature and pressure of the air fuel mixture being high enough to cause self-ignition (compression-ignition) or through assisted ignition. In the embodiments shown in the Figures, means for assisting ignition are omitted, however in certain embodiments, such means may be provided by way of a ‘preheat source’ such as a glow plug, spark plug or other suitable means.

In certain embodiments, a spark ring is positioned at a mid-point of each piston chamber. The spark ring is an annular element which can be slid, for example using a cassette, into the piston chamber. The spark ring includes an anode and cathode which extend into the centre of the spark ring and across which a voltage is applied to generate a spark to assist ignition.

Ignition may also be assisted by retention of a portion of the hot exhaust gas within the piston chamber 16 at the end of the compression cycle. It is anticipated that use of a ‘preheat source’ together with atomised hydrogen would be sufficient to generate a combustion pressure that would be suitable to generate consistent and stable operation.

Following ignition, the air and fuel mixture combusts within the piston chamber 16. This causes an expansion of the gases within the piston chamber 16 which drives the first and second pistons 18, 20 away from each other in opposite directions.

As the pistons 18, 20 moves away from the central region of the piston chamber 16 towards respective end regions of the piston chamber 16, they reveal the first and second exhaust ports 24a, 24b allowing the exhausts gas to be expelled from the piston chamber 16.

When the pistons 18, 20 reach their furthest range of travel along the piston chamber 16, they reach the end of the expansion stoke and therefore complete one power cycle. At this point, the pistons 18, 20 are at a position from which they commence a further compression stroke.

The reciprocal motion of the pistons 18, 20 through the compression and subsequent combustion strokes (i.e. through one complete power cycle) causes each crankshaft 28, 32 to rotate through one complete revolution.

Continuous operation of the device 2 drives the generators 8a, 8b, 8c, 8d synchronously to produce an electrical power output. It will be appreciated that operation of the device 2 is self-perpetuating, but that the initial power cycle may need to be assisted by a starter motor or similar. Variable Valve Timing (WT) software and hardware to manage the fuel mix and injection into the piston chamber via Electronic Direct Injection (EDI) may typically be used. Timing belts may also be used to coordinate air intake, exhaust and piston stroke.

In a further embodiment, an electromagnetic inductor, such as electromagnetic induction ring, is provided proximate the central portion of each piston chamber. By using choreographed repellent electromagnetic fields during or very shortly after combustion can also increase the efficiency of the combustion and add additional force applied to each piston. Variable Valve Timing (VVT) software methodologies can be used to manage this choreography.

In a further embodiment, the device is cooled during use using a refrigerant such as nitrogen or helium gas or other suitable coolant. This ensures that the device/body remains at a low temperature during operation thereby reducing the devices thermal signature and thus reducing thermal stresses and consequential fatigue of the components of the device and so increasing its resilience.

In a further embodiment, an electromagnetic induction coil is arranged around each end of the piston chamber. Each piston comprises a magnetic element or magnetic material such that, at the bottom of each stoke a potential difference is generated by each piston in the respective induction coil. This can be used as an auxiliary generator or for energy harvesting.

It will be appreciated that, in other embodiments, the engine block could take alternative forms to that shown, for example, in Figure 1. For example, in certain embodiments, the engine block could comprise only a single common crankshaft. More specifically, the engine block comprises a plurality of self-contained piston chambers, each piston chamber housing a first and second opposing piston, as described above. The arrangement includes a common crankshaft to which one piston from each piston chamber is connected. This crankshaft is then connected to an electrical generator at each end, in keeping, for example, in Figure 1. However, in contrast to the arrangement shown, for example in Figure 1, the piston chambers are distributed radially about the axis of the common crankshaft and the other piston of each piston chamber are not coupled to a common crankshaft. The radial distribution of the piston chambers is “balanced” such that unstable vibrations do no arise in use.

The device 2 may be coupled with other identical devices to form a modular arrangement in which the number of devices 2 can be selected depending on application/power requirements. They can be arranged in a V, Y or Z arrangement according to requirements.

The device can be configured in terms of displaced volume, operational speed and torque output for desired requirements and power bands.

In a further embodiment there is provided an automotive vehicle, such as an electrically propelled vehicle, comprising: an electrical propulsion system, an energy storage unit, and a device as described above, wherein the device is coupled to the energy storage unit such that electrical energy generated by the device is stored by the energy storage unit. Alternatively, or in addition, the device may be used to directly power the vehicle. Such vehicle is advantageous when access to charging infrastructure is not readily available.

In certain embodiments, an automotive vehicle is provided which is propelled by an electrical propulsion system which is powered by charge from an electrical energy storage device (a battery). The vehicle further includes an electrical energy generating device as described above which is adapted to charge the battery. Further, the automotive vehicle comprises a charge monitoring system to monitor the available charge in the battery and a charging control system adapted to control the electrical energy generating device. When the charge monitoring system detects that a charge level in the battery has fallen below a first threshold level, the charging control system is arranged to activate the electrical energy generating device which charges the battery. When the charge monitoring system detects that the battery has been charged above a second threshold level, the charging control system deactivates the electrical energy generating device. The first and second threshold level can be set to maximise the lifetime of the battery.

In a further embodiment there is provided a truck, such as a rock carrying truck having a 300-tonne carrying capacity for use in mining operations, in which the device is configured to generate electrical energy to power electric motors, such as high-torque electric motors, that drive the wheels of the truck.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features. The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. A device for generating electrical energy comprising:

a device body having at least one piston chamber which defines a piston chamber axis;

a first piston disposed within the piston chamber and arranged to travel along at least a portion of the piston chamber;

a second piston disposed within the piston chamber and arrange to travel along at least a portion of the piston chamber, wherein the first piston and the second piston are arranged to be driven in opposite directions along the piston chamber axis; and at least one electrical generator coupled to at least one of the first piston and the second piston such that motion of the first piston and/or the second piston drives the electrical generator.

2. The device of claim 1, wherein the electrical generator is a first electrical generator coupled to the first piston and the device further comprises a second electrical generator coupled to the second piston.

3. The device of claim 1 or 2, wherein the or each electrical generator comprises at least one direct-drive generator.

4. The device of any one of the preceding claims, wherein the first and second pistons are arranged to define a single combustion chamber between the first piston and the second piston and a wall of the piston chamber.

5. The device of any one of the preceding claims, wherein the first and second pistons are arranged to be driven synchronously.

6. The device of any one of the preceding claims, wherein the piston chamber is provided with at least one fuel intake port and at least one exhaust port.

7. The device of any one of the preceding claims, wherein the fuel intake port is arranged to introduce fuel into a central region of the piston chamber.

8. The device of claim 6 or 7, wherein the exhaust port is arranged to exhaust gases from a central region of the piston chamber.

9. The device of any one of the preceding claims, wherein the device is configured to have a power cycle comprising only two strokes consisting of a single compression stroke in which a mixture of air and fuel is compressed within the piston chamber and a single expansion stroke in which the air and fuel is combusted, exhausted and further air and fuel is introduced to the piston chamber for subsequent combustion.

10. The device of any one of the preceding claims, wherein the piston chamber is provided with an ignition element arranged to initiate combustion of fuel within the piston chamber.

11. The device of any one of the preceding claims, wherein at least one of the first piston and the second piston comprises a magnetic element or magnetizable element.

12. The device of claim 11, wherein said magnetic element or magnetizable element is arranged to produce a force at the beginning of an expansion stroke in the direction of travel of said piston.

13. The device of claim 11 or 12, wherein the device further comprises at least one auxiliary electrical generator comprising at least one coil of electromagnetic material which extends around an end of the piston chamber and is arranged such that motion of said magnetic element or said magnetizable element induces a potential difference in the electrical generator.

14. The device of claim 13, wherein the coil is arranged such that said magnetic element or said magnetizable element enters at least part of the coil at least once during each power cycle thereby inducing a voltage and/or current within the coil.

15. The device of any one of the preceding claims, wherein the device comprises a plurality of piston chambers, wherein a first piston and a second piston are disposed within each of the plurality of piston chambers and arranged to travel along at least a portion of the respective piston chambers and are arranged to be driven in opposite directions.

16. The device of claim 15, wherein the first pistons are coupled to a common first crankshaft which is coupled to at least a first electrical generator and the second pistons are coupled to a common second crankshaft which is coupled to at least a second electrical generator.

17. The device of claim 16, wherein the first crankshaft is further coupled to a third electrical generator and the second crankshaft is further coupled to a fourth electrical generator.

18. The device of any one of the preceding claims, wherein the device is configured to operate using liquid hydrogen as a fuel.

19. The device of any one of the preceding claims, wherein the device comprises a cooling arrangement arranged to cool at least the device body.

20. An apparatus comprising the device of any one of the preceding claims, wherein an output of the at least one electrical generator is coupled to an energy storage device.

21. An automotive vehicle comprising:

an electrical propulsion system;

an energy storage unit; and a device in accordance with any one of claims 1 to 19, wherein the device is coupled to the energy storage unit such that electrical energy generated by the device is stored by the energy storage unit.