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Sunday, 7 July 2013

The hydrogen gas injector plug


                              
  


The hydrogen gas injector plug                       

                   By moses dhilip kumar
abstract
The hydrogen gas injector plug for generating hydrogen gas from ambient air drawn into the piston chamber of an engine includes an array of nozzles fabricated from a metal or a mixture of metals. When heated to a pre-determined temperature, the metallic nozzles react with atmospheric water to disassociate hydrogen gas. The hydrogen gas is injected from the nozzles into the piston chamber and mixed with air. An ignition device ignites the mixture of hydrogen and air so that it burns to power the piston in a conventional manner. The metallic nozzle is heated via a copper conductor connected to a source of electric current.
NEED FOR ALTERNATIVE FUELS
The rising cost and diminishing supply of hydrocarbon fuels, i.e. gasoline, have increased the criticality of developing or finding alternative fuels. Furthermore, pollution caused by burning hydrocarbon fuels is suspected of creating a “greenhouse” effect in the atmosphere, thereby creating problems that may have a bearing on the future course of human civilization. The world would certainly welcome a device that could utilize a virtually inexhaustible supply of a common element to power internal combustion engines, which device would also cause production of pollution-free byproducts. Some well known alternative fuels include biodiesel, bio-alcohol (methanol, ethanol, butanol), chemically stored electricity (batteries and fuel cells), hydrogen, non-fossil methane, non-fossil natural gas, vegetable oil and other biomass sources.
HYDROGEN GAS AS AN ALTERNATE FUEL
Hydrogen is one of two natural elements that combine to make water. Hydrogen is not an energy source, but an energy carrier because it takes a great deal of energy to extract it from water. It is useful as a compact energy source in fuel cells. Many companies are working hard to develop technologies that can efficiently exploit the potential of hydrogen energy. The use of hydrogen as a fuel to power engines has been contemplated for many years. Combustion of this hydrogen produces only pollution-free water. Unfortunately, hydrogen poses many risks when stored in large quantities, thus creating many problems in making the gas available to the general public. Thus a hydrogen gas injector plug solving the aforementioned problem is desired.
Hydrogen does not come as a pre-existing source of energy like fossil fuels, but is first produced and then stored as a carrier, much like a battery. Hydrogen for vehicle uses needs to be produced using either renewable or non-renewable energy sources. A suggested benefit of large-scale deployment of hydrogen vehicles is that it could lead to decreased emissions of greenhouse gases and ozone precursors.
A hydrogen vehicle uses hydrogen as its onboard fuel for motive power. The term may refer to a personal transportation vehicle, such as an automobile, or any other vehicle that uses hydrogen in a similar fashion, such as an aircraft. There are basically two conventional methods of powering a engine using hydrogen, they are:
·         In hydrogen internal combustion engine vehicles, the hydrogen is combusted in engines in fundamentally the same method as traditional internal combustion engine vehicles.
  • In fuel-cell conversion, the hydrogen is reacted with oxygen to produce water and electricity, the latter being used to power an electric traction motor.
Why hydrogen?
The properties that contribute to its use as a combustible fuel are its:

• Wide range of flammability
• Low ignition energy
• Small quenching distance
• High auto-ignition temperature
• High flame speed at stoichiometric ratio
• High diffusivity
• Very low density
But...
The challenges in using the hydrogen in vehicles are production, storage, transport and distribution. Each of these requires great amounts of energy and safety precautions. Because of all these challenges the efficiency of hydrogen will not exceed 25%.
HYDROGEN PRODUCTION
The molecular hydrogen needed as an on-board fuel for hydrogen vehicles can be obtained through many thermo-chemical methods utilizing natural gas, coal (by a process known as coal gasification), liquefied petroleum gas, biomass (biomass gasification), by a process called thermolysis, or as a microbial waste product called bio-hydrogen or Biological hydrogen production. Most of today's hydrogen is produced using fossil energy resources and 85% of hydrogen produced is used to remove sulfur from gasoline. Hydrogen can also be produced from water by electrolysis or by chemical reduction using chemical hydrides or aluminum. Current technologies for manufacturing hydrogen use energy in various forms, totaling between 25 and 50 percent of the higher heating value of the hydrogen fuel, used to produce, compress or liquefy, and transmit the hydrogen by pipeline or truck. Electrolysis is currently the most inefficient method of producing hydrogen, uses 65 to 112 percent of the higher heating value on a well-to-tank basis
In addition to the inherent losses of energy in the conversion of feed stock to produce hydrogen, which makes hydrogen less advantageous as an energy carrier, there are economic and energy penalties associated with packaging, distribution, storage and transfer of hydrogen.
DIFFICULTIES IN STORING HYDROGEN GAS
Hydrogen for use as fuel must first be produced using another energy source, making it a means to transport energy, rather than an energy source, similar to a rechargeable battery. One existing method of hydrogen production is steam methane reformation; however, this method requires methane (most commonly available as natural gas), which raises sustainability concerns. Another method of hydrogen production is through electrolysis of water, in which electricity generated from any source can be used. Photo electrolysis, bio-hydrogen, and biomass or coal gasification have also been proposed as means to produce hydrogen.
Hydrogen is currently impractical as an alternative to fossil-based liquid fuels. While hydrogen has a very high energy content by weight, it has very low energy content by volume, making it very challenging to store in average-sized vehicles. Hydrogen can be stored as compressed hydrogen, as cryogenic liquid hydrogen, or in compounds containing hydrogen which must undergo a chemical change to release the gas such as metal hydrides. However, because of the lower volumetric energy, hydrogen gas tanks would need to be two to three times as large for compressed hydrogen storage as conventional gasoline tanks.
Although hydrogen fuel cells generate no CO2, production of the hydrogen for cars currently creates higher emissions than gasoline cars. While methods of hydrogen production that do not use fossil fuel would be more sustainable, currently renewable energy represents only a small percentage of energy generated, and power produced from renewable sources can be used in electric vehicles and for non-vehicle applications.
Hydrogen has a very low volumetric energy density at ambient conditions, equal to about one-third that of methane. Even when the fuel is stored as liquid hydrogen in a cryogenic tank or in a compressed hydrogen storage tank, the volumetric energy density (mega joules per liter) is small relative to that of gasoline. Hydrogen has a three times higher energy density by mass compared to gasoline (143 MJ/kg versus 46.9 MJ/kg). Because of the energy required to compress or liquefy the hydrogen gas, the supply chain for hydrogen has lower well-to-wheel efficiency but a higher tank-to-wheel compared to gasoline IC's. Some research has been done into using special crystalline materials to store hydrogen at greater densities and at lower pressures. A recent study by Dutch researcher Robin Gremaud has shown that metal hydride hydrogen tanks are actually 40 to 60-percent lighter than an equivalent energy battery pack on an electric vehicle permitting greater range for hydrogen cars.

DISADVANTAGES

• Fuelling fuel cells is still a problem since the production, transportation, distribution and storage of hydrogen is difficult.
• Reforming hydrocarbons via reformer to produce hydrogen is technically challenging and not clearly environmentally friendly.
• The refueling and the starting time of fuel cell vehicles are longer and the driving range is shorter than in a “normal” car.
• Fuel cells are in general slightly bigger than comparable batteries or engines.
• Fuel cells are currently expensive to produce, since most units are hand-made.
• Some fuel cells use expensive materials.
• The technology is not yet fully developed and few products are available.

CONSTRUCTION OF HYDROGEN INJECTOR PLUG
The hydrogen gas injector plug is used for generating hydrogen gas from ambient air drawn into the piston chamber of an engine. The plug comprises an array of nozzles fabricated from one or a mixture of metals. When heated to a pre-determined temperature, the metallic nozzles become “white-hot” and generate photons that react with atmospheric water to disassociate hydrogen gas there from. The nozzle is designed so that no reaction will occur if the temperature is below 350° F. The hydrogen gas is injected from the nozzles into the piston chamber and mixed with air. An ignition device ignites the mixture of hydrogen and air so that it burns to power the piston in a conventional manner. The metallic nozzle is heated via a copper conductor connected to a source of electric current. The electrical conductors are disposed at the first end of the heat insulating member. There are totally 9 nozzles in the array. The nozzle is fabricated of iron alloys and tungsten. The electrical conductors are manufactured from nickel-copper alloy. The hydrogen gas injector plug is fixed in an internal combustion engine and a spark plug is mounted on the piston chamber. Accordingly, it presents a hydrogen gas generator capable of generating small amounts of hydrogen gas from water available in the atmosphere


BRIEF DESCRIPTION OF THE DRAWINGS         
A piston having rings is housed within chamber. The head and the cylinder wall are surrounded by coolant chamber. Conventional intake and exhaust valves (not shown) are also disposed on head. The structure and arrangement of the aforementioned items are conventional and are not part of this new concept. A hydrogen gas generator injector plug and a conventional spark plug are mounted on head. Injector plug and conventional spark plug each have proximate ends disposed within cylinder chamber.


 
20-   Hydrogen injector plug
22-   Circular chamber
22a- Proximate end of chamber
22b- Distal end         of chamber
24-   Insulation chamber
26-   Passageway
28-   Cavity
30-   Nozzle chamber
34-   Electric current conductor
34a- Lower end of conductor
34b- Upper end of conductor
36-   Four electric conductors                                                                         



          FIG. 2 is a side, sectional view of a hydrogen gas generator injector plug according to the present invention.
ASSEMBLY OF HYDROGEN INJECTOR PLUG USING PRO-E
As in diagram the hydrogen gas generator injection plug comprises a circular member fabricated from steel and having a threaded proximate end and a distal end. A passageway extends through member from the distal end to proximate end. An insulation member is disposed in the passageway. Insulation member is fabricated from a material having high temperature insulation characteristics. Member has a first end that is disposed adjacent to, but spaced slightly inwardly of proximate end. The second end of insulation member extends above the distal end of member. A passageway extends through insulation member from second end and terminates at a cavity, which cavity is formed in the first end of insulation member. A nozzle member is positioned in cavity. Nozzle member is fabricated from a metal or a metal mixture that has the ability to react with water at relatively high temperatures to oxidize and generate hydrogen gas. Nozzle member must also have the ability to become “white hot” very quickly when an adequate electrical current is applied thereto. As currently contemplated, iron, certain alloys of iron and tungsten exhibit the requisite abilities needed to function as the nozzle member. It should be noted however, that any metal or alloy could be utilized if suitable. An array of hydrogen gas injector passages is formed in nozzle member. It has been determined that nine injector passages will provide an adequate amount of hydrogen gas to power piston. An electric current conductor, preferably fabricated from copper, extends through passageway. The lower end of conductor abuts nozzle member. The upper end defines a terminal for an electrical connection. Four electrical conductors abut the second end of member and are evenly spaced there around. Conductors are fabricated from a nickel-copper alloy.

WORKING
In use, ambient air containing water vapor is drawn into the cylinder chamber via conventional intake valves (not shown) on the intake stroke. A portion of the air water vapor mixture is forced into injector passages on the compression stroke. An electric current is applied to nozzle member via conductor during the latter part of the compression stroke, heating the nozzle member to a “white-hot” temperature. The water vapor reacts with the metal in nozzle member to oxidize the metal and produce hydrogen gas. The hydrogen gas expands through the passages back into the cylinder chamber where it mixes with the oxygen in the air. Spark plug is fired to ignite the mixture, which mixture burns thereby creating a high gas pressure to drive the piston.
Occasionally (and in some climates), the humidity may be very low and the ambient air will not contain enough water vapor to produce an adequate amount of hydrogen gas to properly drive the piston. In such instances additional water vapor is injected into the intake valve.

ADVANTAGES OF HYDROGEN GAS
Wide Range of Flammability
Hydrogen has a wide flammability range in comparison with all other fuels. As a result, hydrogen can be combusted in an internal combustion engine over a wide range of fuel-air mixtures. A significant advantage of this is that hydrogen can run on a lean mixture. A lean mixture is one in which the amount of fuel is less than the theoretical, stoichiometric or chemically ideal amount needed for combustion with a given amount of air. This is why it is fairly easy to get an engine to start on hydrogen.
Generally, fuel economy is greater and the combustion reaction is more complete when a vehicle is run on a lean mixture. Additionally, the final combustion temperature is generally lower, reducing the amount of pollutants, such as nitrogen oxides, emitted in the exhaust. There is a limit to how lean the engine can be run, as lean operation can significantly reduce the power output due to a reduction in the volumetric heating value of the air/fuel mixture.
Low Ignition Energy
Hydrogen has very low ignition energy. The amount of energy needed to ignite hydrogen is about one order of magnitude less than that required for gasoline. This enables hydrogen engines to ignite lean mixtures and ensures prompt ignition.
Unfortunately, the low ignition energy means that hot gases and hot spots on the cylinder can serve as sources of ignition, creating problems of premature ignition and flashback. Preventing this is one of the challenges associated with running an engine on hydrogen. The wide flammability range of hydrogen means that almost any mixture can be ignited by a hotspot.
High Auto-ignition Temperature
Hydrogen has a relatively high autoignition temperature. This has important implications when a hydrogen-air mixture is compressed. In fact, the autoignition temperature is an important factor in determining what compression ratio an engine can use, since the temperature rise during com\pression is related to the compression ratio.

The temperature rise is shown by the equation:

T2 = T1 (V1/V2)g-1

Where:
V1/V2 = the compression ratio
T1 = absolute initial temperature
T2 = absolute final temperature
γ   = ratio of specific heats
The temperature may not exceed hydrogen’s auto-ignition temperature without causing premature ignition. Thus, the absolute final temperature limits the compression ratio. The high auto-ignition temperature of hydrogen allows larger compression ratios to be used in a hydrogen engine than in a hydrocarbon engine.
This higher compression ratio is important because it is related to the thermal efficiency of the system .On the other hand, hydrogen is difficult to ignite in a compression ignition or diesel configuration, because the temperatures needed for those types of ignition are relatively high.

High Flame Speed
Hydrogen has high flame speed at stoichiometric ratios. Under these conditions, the hydrogen flame order of magnitude higher (faster) than that of gasoline. This means that hydrogen engines can more closely approach the thermodynamically ideal engine cycle. At leaner mixtures, however, the flame velocity decreases significantly.

Low Density
Hydrogen has very low density. This results in two problems when used in an internal combustion engine. Firstly, a very large volume is necessary to store enough hydrogen to give a vehicle an adequate driving range. Secondly, the energy density of a hydrogen-air mixture, and hence the power output, is reduced. speed is nearly an order of magnitude higher (faster) than that of gasoline. This means that hydrogen engines can more closely approach the thermodynamically ideal engine cycle. At leaner mixtures, however, the flame velocity decreases significantly.

AIR/FUEL RATIO

The theoretical or stoichiometric combustion of hydrogen and oxygen is given as:

2H2 + O2       = 2H2O

Moles of H2 for complete combustion = 2 moles
Moles of O2 for complete combustion = 1 mole

Because air is used as the oxidizer instead oxygen, the nitrogen in the air needs to be included in the calculation:


Moles of N2 in air     = Moles of O2 (79%N2in air / 21% O2 in air)
                                    = 1 mole of O2 x (79% N2 in air / 21% O2 in air)
= 3.762 moles N2

Number of moles of air       = Moles of O2 + moles of N2
= 1 + 3.762
= 4.762 moles of air

Weight of O2             = 1 mole of O2 x 32 g/mole
= 32 g
Weight of N2             = 3.762 moles of N2 x 28 g/mole
=105.33 g

Weight of air             = weight of O2 + weight of N (1)
= 32g + 105.33 g
= 137.33 g
Weight of H2             = 2 moles of H2 x 2 g/mole
= 4 g

Stoichiometric air/fuel (A/F) ratio for hydrogen and air is:

A/F based on mass  =mass of air/mass of fuel
            = 137.33 g / 4 g
= 34.33:1

A/F based on volume          = volume (moles) of air/volume (moles) of fuel
= 4.762 / 2
= 2.4:1
The percent of the combustion chamber occupied by hydrogen for a stoichiometric mixture:

% H2 = volume (moles) of H2/total volume (2)
= volume H2/(volume air + volume of H2)
= 29.6%


These calculations show the stoichiometric or chemically correct A/F ratio for the complete combustion of hydrogen in air is about 34:1 by mass. This means that for complete combustion, 34 pounds of air are required for every pound of hydrogen. This is much higher than the 14.7:1 A/F ratio required for gasoline.
Since hydrogen is a gaseous fuel at ambient conditions it displaces more of the combustion chamber than a liquid fuel. Consequently less of the combustion chamber can be occupied by air. At stoichiometric conditions, hydrogen dis-places about 30% of the combustion chamber, compared to about 1 to 2% for gasoline.
For lean A/F ratios, phi will be a value less than one. For example, a phi of 0.5 means that there is only enough fuel available in the mixture to oxidize with half of the air available. Another way of saying this is that there is twice as much air available for combustion than is theoretically required.                                                                                                                                                
THERMAL EFFICIENCY
The theoretical thermodynamic efficiency of an Otto cycle engine is based on the compression ratio of the engine and the specific-heat ratio of the fuel as shown in the equation:

ηth=1-1/(V1/V2)g-1

Where:
V1/V2 = the compression ratio
γ = ratio of specific heats
ηth = theoretical thermodynamic efficiency

If the compression ratio and the specific heat ratio are higher, then the indicated thermodynamic efficiency too would be higher. The compression ratio limit of an engine is based on the fuel’s resistance to knock. A lean hydrogen mixture is less susceptible to knock than conventional gasoline and therefore can tolerate higher compression ratios.
The specific-heat ratio is related to the fuel’s molecular structure. The less complex the molecular structure, the higher the specific-heat ratio. Hydrogen (γ = 1.4) has a much simpler molecular structure than gasoline and therefore its specific-heat ratio is higher than that of conventional gasoline (γ = 1.1).

EMISSIONS

The combustion of hydrogen with oxygen produces water as its only product:
2H2 + O2 = 2H2O
The combustion of hydrogen with air however can also pro-duce oxides of nitrogen (NOx):
H2 + O2 + N2 = H2O + N2 + NOx

The oxides of nitrogen are created due to the high temperatures generated within the combustion chamber during combustion. This high temperature causes some of the nitrogen in the air to combine with the oxygen in the air.


The amount of NOx formed depends on:

• The air/fuel ratio

• The engine compression ratio

• The engine speed
• The ignition timing

• Whether thermal dilution is utilized

In addition to oxides of nitrogen, traces of carbon monoxide and carbon dioxide can be present in the exhaust gas, due to seeped oil burning in the combustion chamber.
Depending on the condition of the engine (burning of oil) and the operating strategy used (a rich versus lean air/fuel ratio), a hydrogen engine can produce from almost zero emissions (as low as a few ppm) to high NOx and significant carbon monoxide emissions.

 

POWER OUTPUT


The theoretical maximum power output from a hydrogen en-gine depends on the air/fuel ratio and fuel injection method used.
As mentioned in Section 3.3, the stoichiometric air/fuel ratio for hydrogen is 34:1. At this air/fuel ratio, hydrogen will displace 29% of the combustion chamber leaving only 71% for the air. As a result, the energy content of this mixture will be less than it would be if the fuel were gasoline (since gasoline is a liquid, it only occupies a very small volume of the combustion chamber, and thus allows more air to enter).
Since both the carbureted and port injection methods mix the fuel and air prior to it entering the combustion chamber, these systems limit the maximum theoretical power obtain-able to approximately 85% of that of gasoline engines. For direct injection systems, which mix the fuel with the air after the intake valve has closed (and thus the combustion chamber has 100% air), the maximum output of the engine can be approximately 15% higher than that for gasoline engines.

Therefore, depending on how the fuel is metered, the maxi-mum output for a hydrogen engine can be either 15% higher or 15% less than that of gasoline if a stoichiometric air/fuel ratio is used. However, at a stoichiometric air/fuel ratio, the combustion temperature is very high and as a result it will form a large amount of nitrogen oxides (NOx), which is a criteria pollutant. Since one of the reasons for using hydrogen is low exhaust emissions, hydrogen engines are not normally designed to run at a stoichiometric air/fuel ratio.
Typically hydrogen engines are designed to use about twice as much air as theoretically required for complete combustion. At this air/fuel ratio, the formation of NOx is reduced to near zero. Unfortunately, this also reduces the power out-put to about half that of a similarly sized gasoline engine. To make up for the power loss, hydrogen engines are usually larger than gasoline engines, and are equipped with turbochargers or supercharger.







CONCLUSION
Hydrogen being the lightest element can replace the fossil fuel and acts as a renewable energy resources .Although the method was developed earlier hydrogen storage was difficult and dangerous this method injecting hydrogen using the hydrogen gas injector plug  is fruitful overcoming all the difficulties in storing hydrogen in liquid form and lead to a pollution free atmosphere . Further the power and fuel consumption is much more better than the conventional internal combustion engine




REFERENCES
1.Linde Division of Union Carbide Corporation, "Survey Study of the Efficiency and Economics of Hydrogen Liquefaction," Contract NAS 1-13395, NASA, Hampton, Virginia, April 8, 1975.
Figure 1
2. Billings, R.E., "The Hydrogen Engine, A Solution to Pollution," Report Distributed at the 17th International Science Fair, Dallas, Texas, May, 1966.
3.Chao, R.E., and Cox, K.E., "An Analysis of Hydrogen Production Via Closed-Cycle Schemes," THEME Conference, Miami, Florida, March 18-20, 1974.
4.www.geocities.com/flynn/hydrofuel/ - A Comprehensive study of hydrogen as fuel
5.Alternate Fuels – Boris and Davis







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