Internal Combustion Engine Having On-Board Electrolyzer And Method Of Using Same

Abstract

A method and apparatus for treating the exhaust gases and improving fuel efficiency of an internal combustion engine is shown, wherein an on board electrolyzer is employed to produce hydrogen (H2) and oxygen (O2) that are used to maximize the fuel efficiency and minimize exhaust emissions.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of provisional patent application No. 60/716,331 filed Sep. 12, 2006 and provisional patent application No. 60/718,072 filed Sep. 16, 2006.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to internal combustion engines, and more particularly to a method and apparatus for treating the exhaust gases and improving fuel efficiency.

2. Description of the Prior Art

In vehicles having internal combustion engines, performance and control of the exhaust emissions must be improved. The improvements in performance and in the quality of the exhaust emissions can be achieved in dealing with the after-treatment, as well as in-cylinder treatment.

In the after-treatment, NOX traps have been employed to decrease the amount of NOX that is released in the exhaust gases. The amount of NOX in the exhaust from internal combustion engines may be elevated when the engine is operating lean. Lean operation of an internal combustion engine improves fuel economy by reducing the pumping losses and improving the thermodynamic efficiency. However, the exhaust from such engines may contain a large amount of excess oxygen for extended periods of time and thus increase the amount of NOX in the emission system.

To control NOX emissions during lean operation, emission control devices capable of storing NOX during lean operating conditions may be employed. Periodically, as the NOX capacity of the NOX trap is approached, the air-fuel ratio may be driven to a rich condition for a few seconds in order to purge the NOX trap of the stored NOX and to regenerate the NOX storage capacity of the trap.

Another of the exhaust treatments is the selective catalytic reduction. However, there are area infrastructure and safety issues that must be addressed when dealing with this process.

Both of the processes are in need of further development. This is particularly true when considering the EPA emission regulation regarding NOX emissions. These EPA regulations call for a reduction in NOX emissions from 1.2 g/bhp-hr. in 2007 to 0.2 g/bhp-hr. in 2010. It is believed that the former can be met primarily using cylinder technologies and the latter will involve a combination of in cylinder and exhaust after-treatment technologies.

The after-treatment technology must be capable of reducing as much NOX as possible to N₂ and H₂O.

In the in cylinder treatment, it has been suggested to use small amounts of hydrogen added to the hydrocarbon fuel-air mixture to increase the efficiency or reduce the pollution of the internal combustion engine. The difficulties in using hydrogen either as the sole fuel or in combination with a conventional internal combustion engine results from the hydrogen being a ubiquitous and very flammable gas, so that storage increases the hazards of operating the engine and in the general inefficiency in generating the hydrogen such as through electrolysis on the vehicle.

Ammonia has been mentioned as a constituent of various types of fuels in the past, both for internal combustion engines and for jet propulsion. One such fuel is a liquid mixture of ammonias nitrate in liquid ammonia which is a self-sustaining fuel combination requiring no addition of an oxidant such as air. Ammonia is also used to manufacture hydrazine, a well known rocket fuel, and while ammonia does not support combustion, it will burn when mixed with oxygen in air to give a variety of products, principally nitrogen and water. Mixtures of nitrous oxide and ammonia in a rate of 3 to 2 will detonate with some violence yielding nitrogen and water.

In accordance with the results of the prior art, it has been found that as a viable alternative to hydrogen as the sole fuel for internal combustion engines ammonia employment is a viable option. There are no large development costs and the price of a vehicle powered by an ammonia fueled internal combustion engine is not significantly increased. In addition, the fuel is presently abundant and the fuel handling technology already exists and is user friendly.

Ammonia based fuels offer a great potential for universal use. A disadvantage in using ammonia based fuels is that pure ammonia is not suitable for use in high speed engines, as the flame speed is too slow. Also, inherent with the use of ammonia based fuels in internal combustion engines, the initiation of combustion has caused a problem.

It has been found that by doping ammonia with environmentally friendly chemical additions, the flame speed may be improved.

Notwithstanding the disadvantages, there are many advantages to be achieved by adopting an ammonia based fuel technology. A resultant effect is the ability of internal combustion engines which operate with a clean burn at high efficiencies and a reduction in the dependency on fossil fuels.

It has been surprisingly discovered that many of the disadvantages noted above many be overcome by the production of an internal combustion engine wherein hydrogen (H₂) is injected from an antechamber adjacent to and in connection with the combustion chamber, a high efficiency oxidation of NH₃ fuel can be achieved.

Accordingly, it is an object of the present invention to produce an internal combustion engine capable of operating on an ammonia based fuel which effectively overcomes the above problems.

It is also an object of the invention to produce a method and apparatus for improving the exhaust emissions of internal combustion engines.

Another object of the invention is the production of an internal combustion engine after-treatment of the exhaust emissions therefrom.

Still another object of the invention is to produce a method and apparatus for treating the exhaust emissions by the introduction of hydrogen as a reductant in a lean NOX trap for converting N0₂ to N₂.

SUMMARY OF THE INVENTION

The above objects may typically be achieved by a system for treating the exhaust emissions comprising internal combustion engine including an exhaust gas converter for capturing NO₂; a source of hydrogen; means for directing the hydrogen to the exhaust gas converter for converting the NO₂ therein to N₂; and means for exhausting the exhaust from said engine free from NO₂.

Additionally, the above objects may typically be achieved by an improvement in an internal combustion engine characterized by an internal combustion engine including at least one combustion chamber; a source of hydrogen; and a first conduit means providing communication between said source of hydrogen and the combustion chamber for introducing hydrogen into the combustion chamber.

The above object may typically be achieved by method for treating exhaust emissions comprising the steps of providing an internal combustion engine including an exhaust gas converter for capturing NO₂; providing a source of hydrogen; causing the hydrogen to enter the exhaust gas converter, whereby the NO₂ contained therein is converted to N₂; and exhausting the exhaust from said engine free from NO₂.

BRIEF DESCRIPTION OF THE DRAWINGS

The above objects and advantages of the invention will become readily apparent to those skilled in the art from reading the following detailed description of an embodiment in the light of the accompanying drawings, in which:

FIG. 1 shows a flow diagram of a shaft power path and a waste power path of an internal combustion engine employing an on-board electrolyzer in accordance with an embodiment of the invention;

FIG. 2 shows a list illustrating the benefits of employing the electrolyzer shown in FIG. 1 in an internal combustion engine; and

FIG. 3 shows a cross section of a combustion chamber of an internal combustion engine in accordance with another embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION

The following detailed description and appended drawings describe and illustrate various exemplary embodiments of the invention. The description and drawings serve to enable one skilled in the art to make and use the invention, and are not intended to limit the scope of the invention in any manner. In respect of the methods disclosed and illustrated, the steps presented are exemplary in nature, and thus, the order of the steps is not necessary or critical.

Referring to the drawings, and more particularly FIGS. 1 and 2, there is shown a system 10 incorporating the present invention along with a list illustrating the benefits achieved by the system 10. The system includes an internal combustion engine 12 having two primary power paths: 1) shaft power, and 2) waste power. The system 10 can be used with various engine types, including but not limited to diesel fueled internal combustion engines and gasoline fueled internal combustion engines.

Considering the waste power path, the exhaust gases are employed to drive an alternator 14 which, in turn, powers an on-board electrolyzer 16 for producing hydrogen (H₂) and oxygen (0₂). Considering the shaft power path, a belt driven alternator 18 powers the on board electrolyzer 16 for producing hydrogen and oxygen.

As used in exhaust emissions treatment, the hydrogen produced by the electrolyzer 16 is introduced as a reducing agent to an exhaust after-treatment 20 which typically includes a lean NOX trap (not shown). The NOX is trapped in the lean NOX trap during normal engine operation and is typically released when the exhaust is in absence of oxygen. The hydrogen regenerates the NOX trap on a continuous cycle as the NOX trap approaches a predetermined capacity. Favorable results have been found wherein a regeneration cycle occurs approximately three to four seconds out of every 100 seconds.

It was also found that the hydrogen introduction in the exhaust gas stream by the electrolyzer 16 in gasoline fueled engines will effectively reduce the heat-up time of the catalytic converter during cold startup, thus improving the quality of emissions of the engine 12.

The oxygen produced by the electrolyzer 16 is employed as an oxidizing agent to effectively cause regeneration of the diesel particulate filter in diesel fueled engines converting the particulates to CO₂. Additionally, the oxygen is used as an oxidant converting NO to NO₂ upstream of the lean NOX trap.

It will be appreciated that the advantages and improvements brought about through the utilization of the on-board electrolyzer 16 results in improved fuel efficiency and improved quality of the resultant emissions. As used in fuel improvement, the hydrogen (H₂) produced by the electrolyzer 16 may be utilized with the fuel to improve operation, reduce fuel consumption, or reduce emissions.

More specifically, the on-board production of hydrogen by the electrolyzer 16 may be beneficially used to improve operation of a bio-diesel internal combustion engine or an internal combustion engine employing an ammonia, such as anhydrous ammonia. Such an engine is shown in FIG. 3, which shows a cross section of a combustion chamber 112 of an internal combustion engine 110. A piston 114 is adapted to reciprocate by a connecting rod 116 which is connected to an associated crank shaft (not shown).

A source 118 of anhydrous ammonia (NH₃) is fed into the combustion chamber 112 by means of an associated conduit means.

The engine 110 is further provided with an antechamber 120 for receiving hydrogen from an appropriate source, such as the electrolyzer 16 discussed above, in communication with the antechamber 120. The antechamber 120 is in communication with the combustion chamber 112 of the engine 110 permitting the introduction of hydrogen. A spark plug or glow plug (not shown) is disposed within the antechamber 120.

In operation, the hydrogen is caused to be ignited by the spark plug or glow plug, causing the pressure and temperature of the hydrogen in the antechamber 120 to rise. This condition causes the hydrogen to issue from the antechamber 120 into the combustion chamber 112 of the engine 110 as a stream of hot gas. The hot gas then interacts with the anhydrous ammonia in the combustion chamber 112 of the engine 110. The interaction causes combustion of the anhydrous ammonia, which consequently forces the piston 114 of the engine 110 to be thrust downwardly to complete the combustion stroke of the engine 110.

As a supplement to hydrocarbon fuel, hydrogen produced by the electrolyzer 16 can improve idle operation and militate against carbon deposits in bio-diesel fueled engines and reduce fuel consumption and emissions in gasoline fueled engines.

As a substitute for hydrocarbon fuel in diesel fueled engines, hydrogen produced by the electrolyzer 16 can reduce fuel consumption, improve cold start operation, and reduce emissions while running in idle mode. In gasoline fueled engines, the substituted hydrogen can reduce fuel consumption and reduce emissions in cold start operation.

From the foregoing description, one ordinarily skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications to the invention to adapt it to various usages and conditions.

Claims

1. A system for treating exhaust emissions comprising:

an internal combustion engine including an exhaust gas converter for capturing NO2;

a source of hydrogen;

means for directing the hydrogen to the exhaust gas converter for converting the NO2 therein to N2; and

means for exhausting the exhaust from said engine free from NO2.

2. The system for treating exhaust emissions according to claim 1, wherein said source of hydrogen is an on-board electrolyzer.

3. The system for treating exhaust emissions according to claim 1, wherein said internal combustion engine includes a source of anhydrous ammonia.

4. The system for treating exhaust emissions according to claim 3, further comprising a first conduit means providing communication between the source of anhydrous ammonia and a combustion chamber for introducing anhydrous ammonia into the combustion chamber.

5. The system for treating exhaust emissions according to claim 4, further comprising a second conduit means providing communication between said source of hydrogen and the combustion chamber for introducing hydrogen into the combustion chamber, the second conduit means including means for causing combustion of the hydrogen to react with the anhydrous ammonia in the combustion chamber of the engine.

6. The system for treating exhaust emissions according to claim 1, further comprising a source of oxygen and a means for directing the oxygen upstream of the exhaust gas converter for converting the NO therein to NO2.

7. An improvement in an internal combustion engine characterized by:

an internal combustion engine including at least one combustion chamber;

a source of hydrogen; and

a first conduit means providing communication between said source of hydrogen and the combustion chamber for introducing hydrogen into the combustion chamber.

8. The improvement in an internal combustion engine according to claim 7, further comprising a source of anhydrous ammonia and a second conduit means providing communication between the source of anhydrous ammonia and the combustion chamber for introducing anhydrous ammonia into the combustion chamber.

9. The improvement in an internal combustion engine according to claim 8, wherein the first conduit means includes means for causing combustion of the hydrogen to react with the anhydrous ammonia in the combustion chamber of the engine.

10. The improvement in an internal combustion engine according to claim 7, wherein said source of hydrogen is an on-board electrolyzer.

11. A method for treating exhaust emissions comprising the steps of:

providing an internal combustion engine including an exhaust gas converter for capturing NO2;

providing a source of hydrogen;

causing the hydrogen to enter the exhaust gas converter, whereby the NO2 contained therein is converted to N2; and

exhausting the exhaust from said engine free from NO2.

12. The method for treating exhaust emissions according to claim 11, wherein the source of hydrogen is an on-board electrolyzer.

13. The method for treating exhaust emissions according to claim 11, further comprising the steps of providing a source of oxygen and directing the oxygen upstream of the exhaust gas converter for converting the NO therein to NO2.