GB2457518A

GB2457518A - Electrolytic gas generating apparatus for use with an i.c. engine

Info

Publication number: GB2457518A
Application number: GB0808727A
Authority: GB
Inventors: Stephen Martin; Darryl Watts
Original assignee: OIL DRUM Ltd
Current assignee: OIL DRUM Ltd
Priority date: 2008-05-14
Filing date: 2008-05-14
Publication date: 2009-08-19
Anticipated expiration: 2028-05-14
Also published as: US20090283418A1; WO2009138726A1; GB2457518B; GB0808727D0

Abstract

A gas generating apparatus, for use with an internal combustion engine, comprises a reactor 2 including a housing 11; at least one anode 12 and at least one cathode 14 connected to an electrical energy source; an electrolyte input, eg in the form of an inlet conduit 22 communicating with an electrolyte vessel 4, and a gas output 24,34,50 in fluid communication with an air inlet of the engine. In use, the electrolyte, eg water, is broken down to a gas in the reactor and the product gas, eg oxygen and hydrogen, is supplied to the engine. The electrolyte input provides a flow of electrolyte such that a substantially constant volume of electrolyte is maintained within the reactor 2, eg by means of an electrolyte level sensing switch 36 connected to a flow control valve 39 in the outlet from an electrolyte reservoir 6. A product gas drier 8 may be provided. The energy source, eg controller 60, provides power to the reactor 2 only when the engine is running and if the temperature of the reactor is not above a predetermined value or if there is insufficient electrolyte in the apparatus. A reactor cooling fan may be provided.

Description

Apparatus The present invention relates to gas generating apparatus for use with internal combustion engines and to methods for generating a combustion-enhancing gas and for increasing the efficiency of internal combustion engines.

It is known that the addition of hydrogen gas to the air inlet of an internal combustion engine can increase the efficiency of that engine in terms of the amount of fuel it needs to burn to generate a given power output. In addition, it is known that hydrogen can be generated from water by the process of electrolysis.

According to a first aspect, the present invention provides a gas generating apparatus for use with an internal combustion engine, the apparatus comprising a reactor including a housing, at least one anode and at least one cathode located within the housing, an electrolyte input and a gas output, wherein the at least one anode and the at least one cathode are electrically connected to an electrical energy source; the electrolyte input is adapted to provide in use a flow of electrolyte such that a substantially constant volume of electrolyte is maintained within the reactor; and the gas output is in fluid communication with an air inlet of the engine, whereby in use electrolyte is broken down to a gas product in the reactor and the product gas is supplied to the engine.

The present invention generates the product gas and supplies it directly to the engine. This avoids the need to store potentially flammable and/or explosive gases, often under pressure, in the vehicle.

The generated product gas is consumed as it is generated and it is typically maintained as a relatively low pressure gas between generation and supply to the engine.

By having a reactor which includes an electrolyte input providing a flow of electrolyte into the reactor, it is possible to generate a product gas from the electrolyte at a high flow rate from a relatively small reactor. For example, a gas flow rate of at least 3.5 litres per minute of product gas may be generated from a reactor having a capacity of less than one litre of electrolyte.

In addition, the conversion of electrolyte to product gas is maintained at a substantially constant rate compared with electrolysis reactors which are only periodically topped up with electrolyte. In such reactors, the conversion rate of electrolyte to product gas starts off being relatively high as the anode(s) and cathode(s) are completely covered by the electrolyte. However, as the electrolyte is consumed by conversion to the product gas, the electrolyte level drops and progressively less surface area of the anode(s) and cathode(s) is available for the electrolytic conversion process. This results in an approximately exponential reduction of the conversion rate as the electrolyte fluid level in the reactor is reduced.

A further known problem with the electrolysis process is the build up of heat in the reactor. This can be a significant issue where the product gas is a potentially flammable or explosive mixture. The arrangement of the gas generating apparatus as claimed addresses also this problem. In particular, the flow of electrolyte into the reactor via the electrolyte input helps to reduce the temperature build-up within the reactor as relatively cool fluid is flowing into the reactor.

As the gas generating apparatus is for use with internal combustion engines, the electrical power source for the reactor is conveniently the same as the electrical power source for the engine. Thus, the power source may be one or more batteries which typically have an output of twelve or twenty four volts.

In an embodiment of the invention, the electrolyte input includes a pump to provide the flow of electrolyte into the reactor. Optionally the pump is a mechanical pump or a gravity pump. By the term "gravity pump", it is meant that electrolyte is urged into the reactor by the action of gravity.

Thus, for embodiments employing a gravity pump, a source of electrolyte is located above the reactor whereby it has a greater potential energy. The pump ensures that a suitable flow of electrolyte into the reactor is maintained.

Suitably, the electrolyte input pump is a gravity pump and the apparatus further includes an electrolyte vessel located above the reactor, the electrolyte vessel being in fluid communication with the electrolyte input of the reactor. A gravity pump increases the reliability of the apparatus as there are no moving parts within a gravity pump to wear or fail. However, a gravity pump requires that there is sufficient free area in the engine space to mount the electrolyte vessel above the reactor. If this is not possible within the space restraints, then a mechanical pump may be used to provide the electrolyte flow to the electrolyte input of the reactor.

The skilled person will appreciate that the term "above" does not require the electrolyte vessel to be located directly or immediately above the reactor, but that the electrolyte in the electrolyte vessel simply must have a greater potential energy than the electrolyte in the reactor such that the flow of electrolyte under the action of gravity will be from the vessel to the reactor.

In embodiments of the invention as defined anywhere above in which the apparatus includes an electrolyte vessel and employs a gravity pump to provide the flow of electrolyte to the input of the reactor, the apparatus may further include an electrolyte reservoir in fluid communication with the electrolyte vessel, such that the electrolyte volume in the electrolyte vessel is maintained substantially constant. In such an embodiment, the fluid pressure provided to the electrolyte input by the gravity pump is maintained substantially constant. In certain embodiments, the apparatus may include a valve which permits flow of electrolyte from the reservoir to the vessel when the volume of electrolyte within the vessel reaches a pre-determined level. The valve may be controlled by a fluid level detector which is capable of detecting the electrolyte volume in the electrolyte vessel.

The product gas generated by the reactor is exhausted via the gas output. It has been found that the flow of product gas may have entrained therein a significant proportion of electrolyte. In view of this finding, embodiments of the invention as defined anywhere above which include an electrolyte vessel may be adapted such that the gas output is connected to the engine air inlet via the electrolyte vessel. In this arrangement, the action of bubbling the product gas through the electrolyte contained within the electrolyte vessel removes at least some of the electrolyte entrained within the product gas flow and returns it to the electrolyte vessel.

In order to remove remaining electrolyte from the product gas flow, the apparatus as defined anywhere above may include a gas purifier which is capable of removing at least some of the residual electrolyte from the product gas. The gas purifier is suitably located between the reactor and the engine air inlet.

In an embodiment of the invention as defined anywhere above, the apparatus further includes a cooling system capable of maintaining the temperature of the reactor within a desired range. Such a cooling system may include a fan which is arranged to direct a flow of air over the reactor and/or the electrolyte input. It may further include one or more temperature sensors which are capable of sensing the temperature of the electrolyte. The temperature sensors may form part of a cooling system controller, which is capable of controlling the operation of the cooling system.

In a further embodiment of the invention as defined anywhere above, the apparatus includes a reactor controller which is adapted to energise the reactor only when the engine is running. This results in an apparatus that generates the product gas only when it is needed: a so-called "on demand" system. In such an embodiment, the problem of storing the product gas or the waste involved by venting it to the atmosphere is avoided and the reactor generates only a flow of product gas that is suitable for use in the engine. The reactor controller may connect the at least one anode and the at least one cathode to the electrical energy source only when the engine is running.

The product gas typically includes hydrogen. As one of the cheapest and most plentiful sources of hydrogen is water, the electrolyte is suitably water. In embodiments of the invention in which the electrolyte is water, the product gas is a mixture of hydrogen and oxygen.

In a further embodiment of the invention as defined anywhere above, the anode and the cathode are metallic plates. Suitably the reactor contains a plurality of anode plates and a plurality of cathode plates. There may be an insulating element located between the anode plates and the cathode plates. The insulator is suitably formed from a polymeric material The skilled person will appreciate that it is possible to combine one or more of the optional features defined above in connection with specific embodiments. Thus, all such combinations of optional features are included within the scope of the invention. For example, the term "embodiment of the invention as defined anywhere above" means the invention as defined in its broadest sense or as defined in any embodiment thereof.

According to a further aspect of the invention, there is provided a method of generating a combustion-enhancing gas for use in an internal combustion engine, the method including providing a flow of electrolyte to a gas generating apparatus as defined anywhere above and removing the gas product from the gas output.

The method may include generating a product gas which includes hydrogen, in which case the electrolyte is suitably water and the product gas comprises a mixture of hydrogen and oxygen.

According to a yet further aspect of the invention, there is provided a method of increasing the efficiency of an internal combustion engine, the method including generating a combustion-enhancing gas as defined above and introducing the gas into the air inlet of the engine.

An embodiment of the invention will now be described in detail, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a schematic cross-sectional view of an apparatus according to the invention.

The exemplified apparatus includes a reactor 2, an electrolyte vessel 4, an electrolyte reservoir 6 and a gas purifier in the form of a drying unit 8.

The reactor 2 includes of a plurality of anode plates 12, a plurality of cathode plates 14 and an insulating plate 16 formed from a non-conductive polymeric material located between the anode plates and the cathode plates. Figure 1 shows three anode plates 12 and three cathode plates 14, but the skilled person will appreciate that the number of anode and cathode plates is not an essential feature of the invention.

The anode plates 12 and the cathode plates 14 have a rectangular cross section and are made from a suitable electrically conductive material such as 316 grade stainless steel. Each of the anode plates 12 are spaced from the neighbouring anode plates 12 by one or more suitable spacers (not shown) and similarly, each of the cathode plates 14 are spaced from the neighbouring cathode plates 14 by one or more suitable spacers (not shown). The skilled person will be familiar with the spacing of anode and cathode plates in electrolysis reactors and as such, the specific spacing arrangement will not be described in more detail.

The anode plates 12 are electrically connected together and are connected to a positive terminal of a controller 60. Similarly, the cathode plates 14 are electrically connected together and are connected to a negative terminal of the controller 60. The controller 60 is in turn connected to suitable positive and negative terminals of the electrical power source for the internal combustion engine, which is typically one or more twelve or twenty four volt batteries. The controller 60 operatively connects the anode plates 12 and the cathode plates 14 to the electrical power source when the engine is running, provided that a "kill" signal has not been sent to the controller 60. The "kill" signal will be discussed further below.

The anode plates 12, the cathode plates 14 and the insulating plate 16 are housed within a reactor housing 11. The reactor housing is made from a suitable material, such as a chemical-resistant polymer (e.g. polypropylene).

The reactor housing 11 includes an electrolyte input in the form of an inlet conduit 22 in fluid communication with the electrolyte vessel 4 and a gas output in the form of an output conduit 24 which is also in fluid communication with the electrolyte vessel 4.

The electrolyte vessel 4 includes a vessel housing 30 formed using the same polymeric material as the reactor housing 11, the vessel housing 30 including an electrolyte output port 31, which opens into the reactor inlet conduit 22; a product gas inlet port 33, which opens into the reactor output conduit 24; an electrolyte inlet port 35, which opens into a reservoir electrolyte conduit 32; and a product gas exhaust port 37 which opens into an exhaust conduit 34.

The vessel housing 30 also includes an electrolyte level sensing switch 36, which is operatively connected to an electrolyte flow control valve 39 located in the reservoir electrolyte conduit 32, a first temperature sensor 38 and a second temperature sensor 40. The first temperature sensor 38 is operatively connected to a cooling system (not shown) comprising a fan arranged to direct a flow of air over the reactor 2 and the reactor inlet conduit 22. The second temperature sensor 40 is operatively connected to the controller 60.

The electrolyte reservoir 6 comprises a housing 42 capable of storing electrolyte 10, an outlet port 41 which opens into the reservoir electrolyte conduit 32, and a removable cap 44. The reservoir housing 42 is made from a suitable material, such as a polymeric material which is inert to the electrolyte 10.

The product gas drier 8 is a conventional gas drying vessel and includes an inlet port 51, which opens into the exhaust conduit 34; an outlet port 53, which opens into an engine supply conduit 50; and an electrolyte collection portion 55. As the gas drying vessel 8 is a component that would be well known to those skilled in the art, it will not be described in more detail herein.

The controller 60 controls the operation of the reactor 2. It is adapted to provide electrical power to the anode plates 12 and cathode plates 14 only when the engine is running. In addition, it is adapted to interrupt the power to the reactor if the temperature of the reactor 2, as sensed by the second temperature sensor 40, increases above a pre-determined value or if there is insufficient electrolyte ri the apparatus. Thus, if the temperature sensor 40 senses that the temperature within the electrolyte vessel 4 has risen above a pre-defined threshold value, a "kill" signal is sent to the controller 60, which disconnects the reactor 2 from the electrical power source, thereby shutting down the reactor 2.

In use, the reservoir cap 44 is removed and the reservoir 6 is filled with electrolyte 10, which in the case of this example is distilled water. The electrolyte level sensing switch 36 causes the electrolyte flow valve 39 to open and electrolyte 10 flows into the electrolyte vessel 4 via the reservoir conduit 32 and the electrolyte inlet port 35. The electrolyte 10 also flows into the reactor 2 via the electrolyte output port 31 and the reactor inlet conduit 22, and initially the gas output conduit 24. The electrolyte 10 continues to flow from the reservoir 6 into the reactor 2 and the electrolyte vessel 4 until the desired level in the electrolyte vessel 4 is achieved, at which point the electrolyte level sensing switch 36 causes the flow valve 39 to close. The reservoir 6 is filled with additional electrolyte and the cap 44 is replaced.

When the internal combustion engine is started, the controller 60 connects the anode plates 12 to a positive terminal of the engine's electrical power source and the cathode plates 14 to a negative terminal of the electrical power source and the charged plates 12, 14 cause electrolysis of the water to generate hydrogen gas at the cathode plates 14 and oxygen gas at the anode plates 12. The gases generated by the electrolysis process form the product gas which rises to the top of the reactor 2 and exits via the gas output conduit 24.

As the electrolyte 10 is consumed by the electrolysis process and converted to hydrogen and oxygen gas, fresh electrolyte 10 is introduced into the reactor 2 from the electrolyte vessel 4 by a gravitational force acting on the electrolyte 10 in the electrolyte vessel 4. This steadily reduces the volume of the electrolyte 10 in the electrolyte vessel 4 until it reaches a pre-determined level, whereupon the electrolyte level sensing switch 36 causes the electrolyte flow valve 39 to open and permit the flow of electrolyte 10 into the electrolyte vessel 4 from the reservoir 6 via the reservoir conduit 32 and inlet port 35. Once the electrolyte level in the electrolyte vessel 4 has been topped-up from the electrolyte reservoir 6, the electrolyte level sensing switch 36 causes the flow valve 39 to close.

This arrangement results in a certain minimum head of pressure being maintained in the electrolyte vessel 4, which urges fresh electrolyte 10 into the reactor 2 to replace the electrolyte 10 which has been consumed by the electrolysis process.

As mentioned above, the product gas, namely hydrogen and oxygen, flows out of the reactor 2 via the gas output conduit 24. However, the gas flow has entrained within it a significant volume of electrolyte. In order to strip at least some of the entrained electrolyte from the gas flow, the product gas is bubbled through the electrolyte 10 contained within the electrolyte vessel 4. This bubbling action removes some of the electrolyte 10 from the product gas and returns it to the electrolyte vessel 4 for it to be recycled back into the reactor 2.

The product gas exits the electrolyte vessel 4 via the product gas exhaust port 37 and exhaust conduit 34.

The product gas flows through the exhaust conduit 34 and into the product gas drier 8 via inlet port 51. The gas drier 8 removes further electrolyte from the product gas and the dried gas exits the gas drier 8 via the outlet port 53 and the engine supply conduit 50. The engine supply conduit 50 transports the flow of product gas to an air inlet of the internal combustion engine (not shown). The electrolyte removed from the product gas is collected in the electrolyte collection portion 55 of the drier 8.

The first temperature sensor 38 senses the temperature of the electrolyte 10 within the electrolyte vessel 4, which is an indicator of the temperature within the reactor 2, as the electrolyte 10 is able to cycle between the electrolyte vessel 4 and the reactor 2. When the temperature sensed by the first sensor 38 reaches a first pre-set threshold value, the temperature sensor 38 causes a cooling fan to generate a flow of cooling air over the reactor 2 and the reactor inlet conduit 22.

The second temperature sensor 40 operates as part of a safety cut-out system. If the temperature of the electrolyte 10 within the electrolyte vessel 4 reaches a second pre-set threshold value, the controller 60 disconnects the anode plates 12 and the cathode plates 14 from their electrical power supply, thereby shutting down the apparatus.

The electrolyte reservoir is typically sized to contain sufficient electrolyte to generate the product gas needed for at least one week's operation of the engine, optionally at least two week's operation of the engine and suitably at least one month's operation of the engine.

The apparatus may further include an electrolyte level sensor (not shown) located within the electrolyte reservoir which is capable of indicating to a user how much electrolyte is contained within the reservoir. The electrolyte level sensor in the reservoir may be capable of causing a "kill" signal to be sent to the controller 60 such that the reactor 2 is shut down in the event that there is insufficient electrolyte in the reservoir to ensure the safe operation of the reactor 2.

Claims

Claims: 1. A gas generating apparatus for use with an internal combustion engine, the apparatus comprising a reactor including a housing, at least one anode and at least one cathode located within the housing, an electrolyte input and a gas output, wherein the at least one anode and the at least one cathode are electrically connected to an electrical energy source; the electrolyte input is adapted to provide in use a flow of electrolyte such that a substantially constant volume of electrolyte is maintained within the reactor; and the gas output is in fluid communication with an air inlet of the engine, whereby in use the electrolyte is broken down to a gas product in the reactor and the product gas is supplied to the engine.
2. A gas generating apparatus according to Claim 1, wherein the electrolyte input includes a pump to provide the flow of electrolyte into the reactor.
3. A gas generating apparatus according to Claim 2, wherein the apparatus further includes an electrolyte vessel located above the reactor, the electrolyte vessel being in fluid communication with the electrolyte input whereby the pump is a gravity pump.
4. A gas generating apparatus according to Claim 3, wherein the apparatus further includes an electrolyte reservoir in fluid communication with the electrolyte vessel, such that the electrolyte volume in the electrolyte vessel is maintained substantially constant.
5. A gas generating apparatus according to Claim 3 or Claim 4, wherein the gas output is connected to the engine air inlet via the electrolyte vessel, whereby at least some of the electrolyte entrained within the gas flow from the reactor is returned to the electrolyte vessel.
6. A gas generating apparatus according to any preceding claim, wherein the apparatus further includes a gas purifier located between the gas output and the engine air inlet, the gas purifier being capable of removing residual electrolyte from the gas product.
7. A gas generating apparatus according to any preceding claim, wherein the apparatus further includes a cooling system capable of maintaining the temperature of the reactor within a desired range.
8. A gas generating apparatus according to any preceding claim, wherein the apparatus further includes a controller which is adapted to energise the reactor only when the engine is running.
9. A gas generating apparatus according to any preceding claim, wherein the electrolyte is water and the gas product comprises a mixture of hydrogen and oxygen.
10. A method of generating a combustion-enhancing gas for use in an internal combustion engine, the method including providing a flow of electrolyte to a gas generating apparatus as claimed in any of Claims 1 to 9 and removing the gas product from the gas output.
11. A method according to Claim 10, wherein the electrolyte is water and the combustion-enhancing gas comprises a mixture of hydrogen and oxygen.
12. A method of increasing the efficiency of an internal combustion engine, the method including generating a combustion-enhancing gas according to Claim 10 or Claim 11 and introducing the gas into the air inlet of the engine.Amendments to the claims have been filed as follows 1. A gas generating apparatus for use with an internal combustion engine, the apparatus comprising (i)a reactor including a housing, at least one anode and at least one cathode located within the housing, an electrolyte input and a gas output, and (ii) an electrolyte vessel, wherein the at least one anode and the at least one cathode are electrically connected to an electrical energy source; the electrolyte input is in fluid communication with the electrolyte vessel and is adapted to provide in use a flow of electrolyte such that a substantially constant volume of electrolyte is maintained within the reactor; and wherein the gas output is in fluid communication with the electrolyte vessel, whereby at least some of the electrolyte entrained within the gas flow from the reactor is returned to the electrolyte vessel in use.2. A gas generating apparatus according to Claim 1, wherein the electrolyte input includes a pump to provide the flow of electrolyte into the reactor.3. A gas generating apparatus according to Claim 2, wherein the electrolyte vessel is located above the reactor and the pump is a gravity pump.4. A gas generating apparatus according to any preceding claim, wherein the apparatus further includes an electrolyte reservoir in fluid communication with the electrolyte vessel, such that the electrolyte volume in the electrolyte vessel is maintained substantially constant.5. A gas generating apparatus according to any preceding claim, wherein the apparatus further *:::5 includes a gas purifier located between the gas output and the engine air inlet, the gas purifier being capable of removing residual electrolyte from the gas product. 4,.. 6. A gas generating apparatus according to any preceding claim, wherein the apparatus further includes a cooling system capable of maintaining the temperature of the reactor within a : )0 desired range. a:)( 12 7. A gas generating apparatus according to any preceding claim, wherein the apparatus further includes a controller which is adapted to energise the reactor only when the engine is running.8. A gas generating apparatus according to any preceding claim, wherein the electrolyte is water and the gas product comprises a mixture of hydrogen and oxygen.9. A method of generating a combustion-enhancing gas for use in an internal combustion engine, the method including providing a flow of electrolyte to a gas generating apparatus as claimed in any of Claims 1 to 8 and passing the gas product from the gas output through the electrolyte vessel.10. A method according to Claim 9, wherein the electrolyte is water and the combustion-enhancing gas comprises a mixture of hydrogen and oxygen.11. A method of increasing the efficiency of an internal combustion engine, the method including generating a combustion-enhancing gas according to Claim 9 or Claim 10 and introducing the gas into the air inlet of the engine. * * . I. SI * S * *L. S* ** *1 S ** S* SIS * 4