Power plants – Internal combustion engine with treatment or handling of... – By electrolysis – electrical discharge – electrical field – or...
Reexamination Certificate
2000-03-03
2001-04-10
Denion, Thomas (Department: 3748)
Power plants
Internal combustion engine with treatment or handling of...
By electrolysis, electrical discharge, electrical field, or...
C060S310000, C204S176000, C422S186070
Reexamination Certificate
active
06212883
ABSTRACT:
BACKGROUND OF THE INVENTION
(a) Field of the Invention
The present invention relates to a method and apparatus for treating exhaust gas produced from the combustion of fuels, and more particularly, to such a method and apparatus wherein the reduction of pollutants is achieved by the use of ozone and water vapor.
(b) Description of the Related Art
Internal combustion engines, which operate by the controlled combustion of hydrocarbon fuels, produce exhaust gases containing the complete combustion products of CO
2
and H
2
O, and also pollutants from incomplete combustion, such as unburnt hydrocarbons (HC) as well as CO, which is a direct poison to human life. Further, due to the very high temperatures produced by the burning of hydrocarbon fuels, thermal fixation of nitrogen from the air results in the detrimental formation of nitric oxides (NO
x
).
The quantity of pollutants varies with many operating conditions of the engine, but it is influenced predominantly by the air-to-fuel ratio in the combustion chamber. Conditions conducive to reducing carbon monoxide and unburnt hydrocarbons (a fuel mixture just lean of stoichiometric as well as high combustion temperatures) cause an increased formation of NO
x
, and conditions conducive to reducing the formation of NO
x
(rich fuel mixture and low combustion temperatures) cause an increase in carbon monoxide and unburnt hydrocarbons in the exhaust gases of the engine. As a result, within the region of stable operation of the internal combustion engine, a significant amount of CO, HC and NO
x
is emitted into the atmosphere.
There has been a proposed three-way catalysis (TWC) technology to reduce the pollutants of the exhaust gases. The TWC technology comprises the use of precious metals Pt, Rh, and Ce. The basic operation of Pt is to oxidize CO and HC to CO
2
and H
2
O, Rh is primarily responsible for the reduction of NO
x
, and Ce functions as an emitter of oxygen. The activity of Rh, however, is reduced in a high oxidizing atmosphere, and Rh may react with CeO
2
at high temperature, reducing the activity of both.
Reduction technology has also proposed the use of ammonia as a reducing agent and V
2
O
5
—TiO
2
as a catalyst, but this is likely to exhaust toxic ammonia gas according to the concentration of NO
x
in the exhaust gas.
Another reducing agent has been proposed using hydrocarbons instead of ammonia in Japanese Laid-Open Patent Application No. 63-100919. A catalyst is used in combination with copper and a porous carrier such as alumina, silica or zeolite. However, this method has drawbacks in that the catalyst is likely to be degraded by SO
x
.
SUMMARY OF THE INVENTION
In view of the prior art described above, it is an object of the present invention to provide a method and apparatus for treating exhaust gas produced from the combustion of fuels.
It is another object of the present invention to provide a method and apparatus for reducing pollutants of incomplete combustion in the exhaust gases treated by the use of ozone and water vapor.
A particularly advantageous feature of preferred embodiments of the present invention is that they can be applied to a variety of different types of internal combustion engines, including, but not limited to, automobiles, trucks, stationary power generators, motor boats and motorcycles.
To achieve these and other objects and features, as embodied and broadly described herein, the invention comprises the steps of:
introducing ozone into the exhaust gas in an ozone contactor which is located downstream from a catalytic converter;
passing the exhaust gas through a muffler having an inlet and an outlet;
introducing water vapor into the exhaust gas prior to the outlet of the muffler; and
passing the exhaust gas through at least a portion of a muffler, thereby reducing at least one pollutant, selected from the group consisting of unburnt hydrocarbons, carbon monoxide and oxides of nitrogen, from a first concentration to a second lower concentration.
According to another aspect of the present invention, an apparatus for treating exhaust gas produced from the combustion of fuels, comprising:
an ozone contactor located downstream from a catalytic converter, for mixing the exhaust gas with ozone;
a muffler having an inlet and an outlet;
a water evaporator for adding water vapor to the exhaust gas; and
a passageway for conducting water vapor into the muffler such that the exhaust gas stream passes through water vapor prior to exhausting from the outlet of the muffler.
Both the foregoing general description and the following Detailed Description are exemplary and are intended to provide further explanation of the invention as claimed.
REFERENCES:
patent: 3984296 (1976-10-01), Richards
patent: 4945721 (1990-08-01), Cornwell et al.
patent: 5121602 (1992-06-01), McCorvey
patent: 5223105 (1993-06-01), Arthurson et al.
patent: 5806305 (1998-09-01), Miller et al.
patent: 5807526 (1998-09-01), Miljevic
patent: 5863413 (1999-01-01), Caren et al.
patent: 6012283 (2000-01-01), Miller et al.
patent: 6033462 (2000-03-01), Chu
patent: 6038853 (2000-03-01), Penetrante et al.
patent: 6038854 (2000-03-01), Penetrannte et al.
patent: 6047543 (2000-04-01), Caren et al.
patent: 6048500 (2000-04-01), Caren et al.
patent: 6153151 (2000-11-01), Moxley et al.
patent: 4231581 (1994-03-01), None
patent: 0070016 (1983-04-01), None
patent: 63-100919 (1988-05-01), None
Denion Thomas
Fish & Richardson P.C.
Moon-Ki Cho
Tran Diem
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