Hydrogen Generating Apparatus

Field of the Invention

The present invention is directed to a hydrogen generating apparatus and in particular a hydrogen generating apparatus for a motor vehicle.

Background

Hydrogen generating apparatus employing electrolysis technologies have been used on motor vehicles to supplement the fuel used to drive the vehicle. The use of hydrogen as a supplemental fuel in motor vehicle engines has been proposed to increase the performance of the engine. Hydrogen and oxygen, when used as part of the air/fuel mixture for the operation of the engine, have been found to increase the performance of the engine by increasing the mileage and by reducing the amount of emissions from the engine. The hydrogen and oxygen may be generated through electrolysis of an aqueous solution with the gases given off being mixed with the charge of fuel and air supplied to the engine.

For use on motor vehicles, hydrogen generating apparatus have been developed that offer secure enclosures for electrolysis cells. In these apparatus, a housing is provided that may be conveniently positioned on the vehicle, the housing enclosing one or more electrolysis cells and other internal components such as control systems, gas lines, electrical conduits, etc. Often the enclosure is produced of durable materials that protect the cells and other internal components against the rigors of operation on a motor vehicle, the elements and by human manipulation. The housing often includes an access cover which is generally lockable to control access to the cells and internal components.

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Although hydrogen generating apparatus have proven useful, there are certain disadvantages that have limited their widespread acceptance. For example, some may be reticent to employ hydrogen generating apparatus because of a perception of risk of explosion by generation of hydrogen gas.

Summary

In accordance with a broad aspect of the present invention, there is provided a hydrogen generating apparatus comprising: a hydrogen generating cell including a container formed by liquid and gas tight walls and a plurality of electrodes within the container for generating hydrogen gas from an electrolyte liquid; a housing about the hydrogen generating cell; a gas delivery line extending from the hydrogen generating cell and passing out of the housing; a space between the hydrogen generating cell and the housing, a sensor in the housing capable of sensing a concentration of hydrogen in the space and a system for controlling operation of the hydrogen generating apparatus in response to a selected concentration of hydrogen being sensed at the sensor.

In accordance with another broad aspect of the present invention, there is provided a method for operating a hydrogen generating apparatus, comprising: providing a sensor capable of sensing a concentration of hydrogen and positioned to detect gas leaked from a hydrogen generating cell; monitoring the sensor to determine if a selected concentration of hydrogen gas is sensed at the sensor; and controlling operation of the hydrogen generating apparatus in response to the detection of the selected concentration of hydrogen gas at the sensor.

It is to be understood that other aspects of the present invention will become readily apparent to those skilled in the art from the following detailed description, wherein various embodiments of the invention are shown and described by way of illustration. As will be realized, the invention is capable for other and different embodiments and its several details are capable of modification in various other respects, all without departing from the spirit and scope of the present invention. Accordingly the drawings and detailed description are to be regarded as illustrative in nature and not as restrictive.

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Brief Description of the Drawings

Referring to the drawings wherein like reference numerals indicate similar parts throughout the several views, several aspects of the present invention are illustrated by way of example, and not by way of limitation, in detail in the figures, wherein:

Figure 1 is a schematic view of a hydrogen generating apparatus according to the present invention; and

Figure 2 is a schematic view of one possible system and method flow chart according to the present invention.

Description of Various Embodiments

The detailed description set forth below in connection with the appended drawings is intended as a description of various embodiments of the present invention and is not intended to represent the only embodiments contemplated by the inventor. The detailed description includes specific details for the purpose of providing a comprehensive understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without these specific details.

A hydrogen generating apparatus is shown in Figure 1 including one or more hydrogen generating cells 10, a housing 12 about the hydrogen generating cells, a space 14 between the hydrogen generating cell and the housing, a sensor 16 in the housing capable of sensing a concentration of hydrogen in the space and a system, generally indicated at 18, for controlling operation, shown in this embodiments as output operations 19A, 19B, 19C, of the hydrogen generating apparatus in response to a selected concentration of hydrogen being sensed at the sensor.

The space may accommodate gas lines, electrical lines, devices for operation control and/or monitoring of the hydrogen generating cell, etc. in addition to the sensor and the one or more hydrogen generating cells. For example, in addition to one or more hydrogen generating cells, and the sensor, a housing of a hydrogen generating

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apparatus may include electrical components 20 such as onboard controllers such as control system 18 or other programmable logic controllers and/or circuit boards, electrical supplies and power controllers, electrical conduits, sensors, etc. Of course it is not always necessary to install all electrical components in the housing, but incorporation of all related components in the housing may facilitate installation and maintenance of the apparatus. The housing may also enclose any or all of filters, electrolyte refilling systems, gas dryers, flame arrestors, etc. Gas delivery lines 22 may extend from the cells and outwardly through the housing, providing a conduit for the gas generated in the cell through the space to the engine without releasing gas into the space. In the illustrated embodiment, the generated gases including hydrogen and oxygen are passed together through the gas delivery line to the engine.

The housing may take various forms. In one embodiment for example, the housing may be formed to protect the cell from tampering, from impact by objects or from the elements. The housing may be formed for mounting internally in a vehicle or externally on the vehicle, as desired. The housing is generally intended to be air filled and protected against entry into and containment of liquid in the space between the one or more cells and the housing. An access port 24 may be provided as a discreet opening in the housing, as shown, or by removal of all or a portion of the housing. Any access may be controlled if desired, for example as by use of a cover 26 and/or a lock 28.

A hydrogen generating cell often includes a container 30 formed by liquid and gas tight walls and a plurality of electrodes 32 within the container for generating hydrogen gas when an electrical current is passed therethrough in the presence of an electrolyte liquid 33 contained in the cell container. Ports 34 through the walls provide for connection to gas delivery lines 22 and electrolyte supply lines and inlet of power lines. Such ports 34 and connections thereto are generally selected to continue the liquid and gas tight envelope of the cell such that leakage of liquid and gas into the housing is substantially avoided under normal operating conditions. Of course, as will be appreciated, a pressure relief valve may be provided in the container walls to avoid an explosion of a cell due to overpressuring. However, such a pressure relief may not generally be intended to constantly and under normal operating conditions release generated gases into the housing.

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The hydrogen generating apparatus and the cells therein are often formed, selected and/or configured to accommodate high concentrations of hydrogen gas without a substantial risk of explosion. However, leaks in the cell that permit a build up of hydrogen gas in the space between the cell and the housing may create an explosion risk. Leaks may occur at various places such as through the walls of the electrolysis cell container and/or gas lines and/or through connections between gas lines and containers and/or through pressure relief valves. Because the housing is generally closed and sealed to protect internal components against the elements and tampering, any such leaked gas may build up in the housing surrounding the cells.

Thus, the system for controlling operation of the hydrogen generating apparatus may be selected to respond to any concentration of hydrogen gas in the housing and which is not contained in the hydrogen generating cell and which is below the explosive limit for hydrogen gas. It is believed that the explosive limit of hydrogen gas is about 40,000 ppm.

In one embodiment therefore, the system may monitor for a selected concentration that is determined to be safe but of concern. For example, the selected concentration may be selected to be less than about 90% or possibly less than 75% of the explosive limit, such as for example in one embodiment less than about 30,000 ppm. However, the selected concentration may be selected to be much less than the explosive limit such as less than 10,000 ppm or less than 7,500 ppm.

In one embodiment, the system for controlling operation of the hydrogen generating apparatus may monitor and/or receive signals from the sensor and may generate an output operation to control the function of the hydrogen generating system based thereon such as for example, the system may include a function, illustrated by 19A, for sending a signal 35 to an operator or a service display or operating system to report the detection of a selected hydrogen concentration. In another embodiment, the system for controlling operation of the hydrogen generating apparatus may include a function, illustrated by 19B, for shutting down operation of the hydrogen generating cell such as by use of a switch 36, in response to the detection of a selected hydrogen concentration. In another embodiment, the apparatus may include a gas exhaust for

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the housing, which may include for example, a fan 38 mounted in the housing that is operable to exhaust gases from the space and, thereby from the housing. In such an embodiment, the system for controlling operation of the hydrogen generating apparatus may include a function, illustrated at 19C, for starting operation of the gas exhaust in response to the selected concentration.

In one possible embodiment shown in schematic form in Figure 2, the system for controlling operation of the hydrogen generating apparatus may monitor 40 a sensor in the housing of a hydrogen generating apparatus to determine 41 if a hydrogen concentration of concern is present in the space surrounding the cells. When such a concentration is detected, a first function of the system generates a signal 42 for the operator and drives operation of a gas exhaust 44 to exhaust gas from the housing. Thereafter, sensor monitoring continues 46 and the system may include a second function that shuts down operation 48 of the hydrogen generating cell in response to the sensing of a second selected concentration that is higher than the concentration of interest and/or if the concentration of concern is not reduced, for example by the gas exhaust, after a selected period.

Where a two stage control is used, a lower concentration limit may be selected to drive exhaust of hydrogen gas from the housing space and a second limit higher than the lower limit is selected for a hydrogen gas generation shut down condition.

Alternately, the second limit may be based on time, wherein if the exhaust function is not achieving a reduction of the hydrogen concentration below the lower concentration limit in a particular time period, the hydrogen generating apparatus will be shut down. As such, the control system may include a timing function for use in these embodiments.

In one embodiment, the system can also include a counter function and can monitor the number of times the selected concentration is reached and may include a function for shutting down operation of the cell once a selected count limit is reached. For example, the apparatus may be configured to shut down if the selected concentration is reached 4 times or 6 times or more.

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It may be useful if the system may only be restarted after a shut down if the apparatus is serviced. Thus, it may be useful if the system includes a function that only permits a restart by entry of a pass code into system 18, such as may be controlled and used only by a service representative.

In addition or alternately to a signal generated to report a concentration of concern, the system may include a function to advise an operator of the apparatus that the system has been shut down, such as a function to generate a "Service Required" signal. Of course any such signals may be audible, visual, for storage in memory and/or for controlling further operations.

The sensor capable of sensing hydrogen gas concentration may be selected to include any of various devices, mechanisms and systems, as will be appreciated by a skilled person. In one embodiment, a sensor using a electrochemical operating principle may be useful. For example, an amperometric sensor may be used that uses hydrogen gas as a target gas to complete a circuit and generate a current through the sensor. The current generated may, for example, be proportional to the measured gas concentration.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to those embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the full scope consistent with the claims, wherein reference to an element in the singular, such as by use of the article "a" or "an" is not intended to mean "one and only one" unless specifically so stated, but rather "one or more". All structural and functional equivalents to the elements of the various embodiments described throughout the disclosure that are know or later come to be known to those of ordinary skill in the art are intended to be encompassed by the elements of the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. If the claim is being considered under the law of the United States of America, no claim element is to be construed under the

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provisions of 35 USC 112, sixth paragraph, unless the element is expressly recited using the phrase "means for" or "step for".

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