WO2016166502A1

WO2016166502A1 - Gas powered reciprocating engine

Info

Publication number: WO2016166502A1
Application number: PCT/GB2016/000085
Authority: WO
Inventors: John Merlin Copplestone-Bruce
Original assignee: John Merlin Copplestone-Bruce
Priority date: 2015-04-17
Filing date: 2016-04-19
Publication date: 2016-10-20
Also published as: GB201506581D0

Abstract

There is provided a cold running reciprocating piston engine comprising a gas supply means which feeds pressurized gas into respective piston cylinders via fluid control valves. The pistons are drive by impulse forces brought about by the introduction of pressurized gas, most likely nitrogen, and in turn drive a conventional crankshaft. Spent gas maybe collected, recompressed and re-used.

Description

Gas powered reciprocating engine

This invention relates to a nitrogen engine. More particularly, the present invention is directed to a piston impulse engine that utilizes pressurized nitrogen as its energy source.

Reciprocating engines, also commonly referred to as piston engines, are well known. In such engines, one or more reciprocating pistons convert pressure into rotating motion. Typically, such engines are "heat" engines, whereby the pressure is provided by the combustion of fossil fuels, such as coal, gas or oil.

Increased industry and transportation using internal combustion engines, multiplied by the exponential increases in highly populated developing markets, have given rise to corresponding increases in the combustion of fossil fuels. Cars, planes, power plants, and other human activities that involve the burning of fossil fuels such as gasoline, petroleum and natural gas for fueling combustion engines has led to increased pollution, most notably in the form of carbon gases and particulates. In the past 150 years, such activities have pumped enough carbon dioxide into the atmosphere to raise its levels higher than they have been for hundreds of thousands of years. Carbon dioxide, a greenhouse gas, is the main pollutant that is causing global warming.

Though carbon is merely .0399% of our air, its variation controls climate. Since the industrial revolution it is estimated that we have added approximately 700 billion metric tons of carbon to the atmosphere, bringing the total to near 2990 billion metric tons. The result is that the C02 content within air has increased from a pre-industrial 280 parts per million (ppm) to 400.26 ppm, as at February 2015. While experts may differ in their opinions on the implications of this increase, and more worryingly the implications if the trend continues, there can be little doubt that the effects of rising carbon dioxide levels are detrimental to the environment, our climate and, ultimately, our health, social and economic well-being.

The momentum of using fossil fuels to energise our machinery and the economic forces that resist change are significant. Yet, notwithstanding this, governments and environmentally aware agencies call summits and devise initiatives for reducing our collective carbon footprint. Nevertheless, most would agree, political posturing aside, these have not been successful to date, or at least have not been sufficiently successful to stem the tide. Certainly the statistics show that use of combustion engines continues to increase, and with that, so does the level of carbon in our atmosphere.

An object of the invention is therefore to provide an alternative to combustion engines, and more particularly, an engine that does not emit carbon dioxide as a pollutant caused, most notably, by the inefficient combustion of fossil fuels. A further object is to provide a clean engine of suitable size, construction and output to permit it to feasibly replace known fossil fuel combustion engines.

The invention seeks to meet this objective through the use of a pressurized gas to drive the pistons within an engine during their respective power strokes. The properties of Nitrogen offer exciting potential for providing impulse forces to drive pistons in an engine. More particularly, nitrogen contained in its liquid state and allowed to warm to ambient temperature would exert a pressure of circa 44,000 psi, and produce approximately 5 times the volume of gas per ml of liquid compared with, for example, carbon dioxide.

Traditionally, piston engines fueled by nitrogen have required cryogenic liquid nitrogen to be mixed with a heat exchange fluid. Upon mixing, the liquid nitrogen would boil and the resultant rapidly expanded (or pressurized) gas would be used to power the piston movement. The heat exchange fluid is often the ambient air, although in some nitrogen engines other heat transfer fluids may be used, including water and glycol.

In the past, nitrogen powered reciprocating engines have been designed such that the boiling and vaporization of the nitrogen occurs in the piston chamber. This has had substantial limitations in the efficiency and utility of such engines, as the resultant expansion has been very difficult to appropriately control or predict.

Yet further, using any cryogenic expansion method has always been ineffective in getting an impulse of gas to expand as quickly as petrol or diesel on ignition, it not being sufficiently explosive to produce a comparable 700psi "push" to drive the piston.

An important realization in the current invention is that it would be beneficial if nitrogen, air or other fluid could be introduced to the piston chamber when already in a pressurized gaseous state. As such, it would not be necessary to also introduce a heat exchange fluid into the piston chamber, giving rise to the potential for a simpler and more efficient engine, and further having the potential for better mediation or control of the resultant forces.

The present invention, therefore, contemplates the combining of a particular valve mechanism to govern the injection of gas, potentially under pressures in excess of 1,500 pounds per square inch (psi), into a piston chamber, whereupon it provides an impulse force to drive piston movement.

Although apparatus adapted to achieve the foregoing might conceivably be operable using one of a number of different gases, nitrogen, for reasons given above, presents as a most suitable gas when working at ambient temperatures. For example, the invention could be applied using carbon dioxide as the pressurized fluid, but much more would be required to achieve the same outputs when compared with nitrogen.

According to the present invention there is provided a reciprocating piston engine comprising a gas supply means and two or more pistons, each piston being housed within a piston cylinder and being mechanically linked to a crankshaft, wherein each piston cylinder is associated with a valve mechanism adapted to regulate the flow of pressurized gas from the gas supply means into a respective piston chamber; wherein the pistons reciprocate in response to forces derived from the pressurized gas.

The gas is not combusted or the product of combustion. Preferably, the gas is Nitrogen. The gas supply means may comprise of a manifold connected via a first mediation valve and a throttle valve to a high pressure cylinder storing the fuel in liquid form, wherein the mediation valve permits the gas under a first very high pressure to be mediated to a lower pressure.

Preferably, the mediation valve is single solid state moving part within a casing to control and mediate fluids from high-pressure supply into metered lower pressure use. The valve may be as described in US patent 8,556,133 to the same inventor.

The reciprocating engine may also be provided with a compressor adapt to receive spent gas via exhaust ports in the piston cylinders. The compressor may communicate with the gas supply means to permit re-use of the gas. The compressor may be powered by battery, photovoltaic cells or both.

Also according to the invention there is provided a cold running piston engine wherein the pistons are driven via an impulse stroke by the introduction of pressurized fluid into respective piston chambers, wherein the fluid is not mixed with a heat exchange fluid in the piston chambers.

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

Figure 1 is a schematic view of a first embodiment of the invention;

Figure 2 is a sectioned elevation of an engine cylinder block;

Figure 3 is a sectioned view of a valve mechanism housed within a piston cylinder;

Figure 4 is a sectioned view of a valve mechanism housed within a piston cylinder modified to include a dampening spring; and

Figures 5 to 7 are sectioned views of the valve mechanism and piston of Figure 4 in respective alternate positions of operation.

Referring firstly to Figure 1, a reciprocating engine in accordance with the present invention is connected to a fluid source. The fluid source comprises of a canister 1 bonded to valve mechanism 2. The fluid canister contains compressed nitrogen at room or ambient temperature at a pressure of approximately 44,000 pounds per square inch.

The valve mechanism 2 is adapted to mediate the high pressure nitrogen supply into a lower pressure supply at, say, 1500 pounds per square inch. A gas conduit tube 3 provides means for communication of the nitrogen, at the lower pressure to the manifold 5.

A needle valve 4 is provided and adapted to throttle or vary the flow rate of gas to the manifold 5. The needle valve may be opened and closed in response to a mechanically linked accelerator.

The manifold 5 is formed within an engine block generally referenced 22. The pressurized gas contained within the manifold 5 is used to feed the fluid control valves 6, 7, 8 and 9. Each of these valves is housed within respective piston cylinders, the cylinders additionally each housing respective cylinders 10, 11, 12 and 13.

A stop plate gasket 41 is provided to ensure the cylinder head is gas tight and to provide an end stop for each of the valves 6, 7, 8 and 9, in use.

A compressor 16 is fed exhausted nitrogen or other working gas, in use, and adapted to re- pressurise same before returning it via conduit 42 to the manifold 5 upstream of the needle valve 4. When the engine is not in use, pressurized gas drawn from the air via molecular sieve 45 may be returned to the fuel tank 1 via high pressure conduit 43 and valve 44. Switch valve 17 may be used to selectively channel gas via conduits 42 or 43. The compressor 16 may be powered by battery 21 and or other photovoltaic means, including panels 18.

The pistons 10 - 13 are attached to a conventional crankshaft (not shown) and reciprocate sequentially in accordance with rotation of the crankshaft in a conventional way. As can be seen in Figure 2, each piston, there numbered 23, is associated with a prodder 24, the upper face of which is disposed to push a moveable component 30 of the valve mechanism from its layoff, 'no flow' position, 34, into its initial (after layoff) 'flow' position, 35. Where the moveable component 30 is in the position referenced 35 the working gas, herein nitrogen, flows at pressure into the cylinder compression chamber 25.

Each of the valve mechanisms, as shown in Fig 2, screwed into the engine block 22, is comprised of a threaded casing 26 providing specified bores within which are set seals 27. A · similar seal 27 is set within the moving part 30 of the valve. The moving part 30 is also supplied with a cross drilled channel 29 to admit gas flow from entry port 31, via the tolerance space, and into delivery channel 28, exiting into cylinder compression chamber 25. Each of the valve mechanisms 6 - 9 are supplied gas 32 by way of manifold 33 regulated by a throttle valve 4 behind which the nitrogen gas supply is maintained at 1500 psi.

Figure 3 shows the valve mechanism in greater detail. Here the moving component, now referenced 54, is slideably mounted within the casing 55, itself threadably secured to the piston cylinder head 47.

The cylinder head 47 has been modified to 4 stroke conversion to allow a side feed 51,52 on the inlet side from the manifold with additional channeling 49, 50 to carry spent nitrogen away to exhaust it to the compressor, to recompress it to the manifold pressure for re-use, as aforementioned.

In Figure 3 the valve mechanism is positioned in the no-flow state, and as such, permits gas in the chamber25 to exhaust. More particularly, when the valve is so disposed, pressurized gas in chamber 25 can exhaust through channel 48 which is aligned with channel 49 in the cylinder casing.

With the exception of seal 53, serving as a buffer stop, notably, there is an absence of seals in the embodiment of Figure 3. This emphasizes that as there is no combustion or heat involved tolerances can be small.

Turning now to Figure 4, a similar piston cylinder is depicted but with a piston 23 also presented. The piston 23 incudes a prodder 24 upon which is mounted a helical spring 56. As will be discussed further below, the rising piston drives spent nitrogen out of the chamber 25 via the channels 48, 49 50 as referenced in Figure 3. The spring 56, by itself, is not sufficient to lift the moving component 30 against the manifold gas pressure but rather it serves to much reduce the force of impact as the 'prodder' 24 lifts the moving part 30 from its exhaust position to its inlet flow position. This can be seen more clearly in Figure 5 in which the piston has lifted the moving component 30 to a few degrees before TDC (top dead centre) to allow time enough, during its passage through TDC, for the nitrogen at high pressure in the manifold to transfer through the inlet 31 and race to the chamber 25 to provide the impulse next to drive the piston, and consequently to drive the crankshaft.

As can be seen from Figure 6, the downward movement of the piston 23 is not simultaneously pursued by the moving component 30 of the valve mechanism. Figure 6 shows the piston 23 beginning to move under impulse towards BDC, the spring being fully released, but the valve mechanism has been closed when the resultant force of the gas entering the piston chamber overcame the resultant force of the higher pressure being applied by gas in the manifold to the smaller top end of the moving part 30. Those skilled in the art will understand the equation being: P (manifold) x top surface area = P (chamber) x bottom surface area. The pressure within the cylinder compression chamber 25, whilst exerting a resultant force to move the piston applies an equal force to close the valve mechanism to its 'no flow' position 36.

Subsequently, and as the piston 23 moves towards BDC under the gas impulse but with the valve closed as in Figure 6, the pressure of the gas providing the impulse begins to lessen in response to the volume of the piston chamber volume increasing. This is shown in Figure 7, where the balance of the competing resultant forces on either side of the moving component 30, causes the valve mechanism to open once more, to allow gas flow to seek to re-establish balance at least fleetingly.

Then, though there is a slight addition to the impulse, as the inlets 39 and 52 align, it being insufficient to bring about a new balance as the piston falls towards BDC, the unsupported moveable component 30 follows until it is arrested by the stop plate gasket 41. At that point the exhaust route is aligned for the piston, as it rises, to evacuate the chamber in readiness of fresh impulse, having again passed through its Fig 4 position to repeat the cycle. It may be seen that the valve mechanisms are clever fluid management devices that for the first time permit pistons to be driven on impulse from a stored compressed fluid, rather than, less efficiently, by introducing fluid to the piston chamber and then warming or burning it.

Advantageously, the valve mechanism is also a proportional device so if the throttle needle valve 4 is barely cracked the impulse will be small. If the specified proportion is 3:2 then, if the manifold pressure were to be taken to 150psi the impulse pressure would be lOOpsi. If the manifold pressure were to be 1,500 psi, and the proportional ratio specification be 3:2, the valve mechanism will close at 1,000 psi to deliver its impulse. This compares favourably with known combustion engines, where, at full throttle ignition of the fossil fuel in a conventional ICE a 700psi impulse might be generated.

In use, the sequence of the Engine is as follows:

a) When the engine is 'laid off, 'closed down', 'stopped' or not in use, each valve mechanism 6,7,8 9 will be returned to its Figure 2, 34 closed position, pending further use. b) Use is initiated by the starter motor turning to rotate the crankshaft to cause the piston next in line to give impulse, to rise past TDC as it causes the piston 'prodder' to lift the large end of the moving component of the valve mechanism from a 'no flow' position 34 to 'flow' position 35. c) Working fluid, such as N2 gas at 1500 psi in the manifold floods, via the valve in position 35, into the compression chamber until the pressure within reaches 1000 psi, at which point the resultant force on the larger end of the moving component of the valve mechanism overcomes the resultant force of 1500 psi to the smaller, manifold, end thereof, and the valve closes to 'no flow', position 36. d) At the point where the rising pressure within the compression chamber exerts enough resultant pressure on the piston head to overcome its stopped inertia, the piston begins to move towards BDC in a first impulse stroke. e) As the piston driven by gas impulsive power moves towards BDC and turns the crankshaft, from c 10 degrees past TDC to c 100 degree from TDC, so another piston has commenced its impulse stroke. f) As the pressure within the compression chamber reaches 1000 psi, concurrently the valve closes as the piston begins its impulse travel. h) As piston travel towards BDC increases volume within the compression chamber, pressure falls below 1000 psi, causing the valve to open to position 37 of Fig 2, in effect following the direction of travel of the piston, itself about to uncover its exhaust port. i) Bearing in mind the relative diameters of piston 23 and channels 30 and 29, the valve at position 37, finding itself unsupported (unable to maintain pressure in the transient flow position 37) again follows the piston direction of travel towards BDC to close down to 'no flow' position 34. j) The piston in passing through BDC allows the spent gas, to void its retained pressure to exhaust and subsequently to potential reuse via compressor 16. k) As the piston moves again towards TDC to complete a revolution it compresses residual gas at - say - a pressure of 20 psi to, if the compression ratio is 10:1, 200 psi, as it rises to TDC, at which point its 'prodder' again opens the valve to allow injection of a fresh charge of gas at 1500, to close concurrently again at 1000 psi, for the piston to commence its next revolution.

If, on starting, the throttle is insufficiently opened then initial gas pressure within the manifold will be insufficient to overcome friction and inertia, pressure can be increased in the manifold, by opening the throttle 4. Or, if the pistons begin to move too quickly, the throttled gas flow can be reduced. By such measures can the engine be slowed, accelerated or stopped. At full throttle, gas at 1500 psi by way of example, in the manifold, will be mediated to a pressure to give piston impulse at - say - 1000 psi.

On ending use, by just closing the throttle, the residual pressure within the manifold will cause each in line valve mechanism 6 - 9 to close to position 34, pending further use. It is envisaged that applications may exist to justify greater efficiency of power, but at higher capital cost, when a conventional engine inlet and exhaust valve configuration could be employed. The exhaust valve being opened throughout the upstroke, venting 'spent' gas to atmosphere, or to a compressor for reuse, but avoiding the power drain of compression of residual gas in each stroke, which would increase efficiency.

Notably, whilst in a conventional hydrocarbon fuelled combustion engine there is a theoretical limit to the BHP per litre deliverable, there would be no such limit in a nitrogen engine.

Since each stroke is an impulse stroke, equating in a petrol engine to a combustion stroke, a 1- litre nitrogen driven engine (confined to 1000 psi impulse power) will equate to a 2 litre, conventional petrol driven, 4-stroke engine. Though akin to a two stroke, with impulse or combustion once per piston revolution, the nitrogen driven unit may be specified to be more powerful. Its power is not restricted to the power that can be delivered by combustion of the crank case compression of fossil fuel, or by fossil fuel compression causing unwanted combustion. Otherwise the pressure and volume of nitrogen injection into the compression chamber to give impulse is restricted to engineering possibility.

An advantage of the present invention lies in the potential to convert existing internal combustion engines to embodiments of the present invention. Adaption of the cylinder heads and inclusion of the valve mechanisms may permit economic production of the invention during a transient stage the world must adopt in moving away from current ICE use. Moreover, by minor adaptation it is possible to convert both 2 and 4 strokes ICEs into carbon emission free engines but not limited in power as is the ICE. It can also be observed that conversion of a conventional 4 stroke ICE to nitrogen impulse power converts a 4 stroke to a 2 stroke engine to deliver twice the power that it produced as a 4 stroke ICE.

Benefits of the invention herein described are plentiful and include the negating of carbon production in use with combustion and exhaust noises eliminated. The engine is adapted to run cold utilizing relatively cheap and abundant fuel such as nitrogen or other suitable fluids.

The invention finds application in all manner of uses from marine to aviation and space, to very small portable engines, down to fuel cells within digital equipment. The engines could be used in domestic environments, commercial settings and both stationary and in transport. All may be 're-fuelled' and be usable wherever there is access to air.

Additionally, such engines may be self-sustaining with a PV/battery powered nitrogen collection system.

Further modifications and improvements may be incorporated without departing from the scope of the invention herein intended.

Claims

Claims:

1. A reciprocating piston engine comprising a gas supply means and two or more pistons, each piston being housed within a piston cylinder and being mechanically linked to a crankshaft, wherein each piston cylinder is associated with a valve mechanism adapted to regulate the flow of pressurized gas from the gas supply means into a respective piston chamber; wherein the pistons reciprocate in response to forces derived from the pressurized gas.

2. An engine as claimed in Claim 1 wherein the gas is not combusted or the product of combustion.

3. An engine as claimed in Claim 1 or Claim 2, wherein the gas is Nitrogen.

4. An engine as claimed in any one of the preceding Claims wherein the gas supply means comprises of a manifold connected via a first mediation valve and a throttle valve to a high pressure cylinder storing the fuel in liquid form, wherein the mediation valve permits the gas under a first very high pressure to be mediated to a lower pressure.

5. An engine as claimed in Claim 4 wherein the mediation valve is a single solid state

moving part within a casing to control and mediate fluids from high-pressure supply into metered lower pressure use.

6. An engine as claimed in any one of the preceding Claims wherein the reciprocating engine further comprises a compressor adapt to receive spent gas via exhaust ports in the piston cylinders.

7. An engine as claimed in Claim 6 wherein he compressor communicates with the gas supply means to permit re-use of the gas.

8. An engine as claimed in Claim 6 or claim 7 wherein the compressor is powered by

battery, photovoltaic cells or both.

9. A cold running piston engine wherein the pistons are driven via an impulse stroke by the introduction of pressurized fluid into respective piston chambers, wherein the fluid is not mixed with a heat exchange fluid in the piston chambers.

10. An engine as generally described in the Description herewith or depicted

accompanying drawings.