Power plants – Internal combustion engine with treatment or handling of... – By electrolysis – electrical discharge – electrical field – or...
Patent
1992-12-29
1995-04-04
Hart, Douglas
Power plants
Internal combustion engine with treatment or handling of...
By electrolysis, electrical discharge, electrical field, or...
55466, 55DIG30, 60311, 422180, F01N 302
Patent
active
054026393
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a process for cleaning exhaust gases, especially those from diesel engines.
During the cleaning of exhaust gases from aerosols, especially soot, there is often the problem that soot particles settle down in the filter and therefore reduce its permeability, so that the soot has to be burnt off from time to time. Therefore it is necessary in common filters to supply pertinent heat quantities to the filter. This process requires temperatures within the magnitude of approx. 600.degree. C. Concerning exhaust gases from diesel engines there is also the possibility of giving additives to the fuel which form molecular ferric oxide in the combustion chamber. This then reduces the combustion temperature of the soot below 400.degree. C., so that the heat of the motor or the heat of the exhaust gases is sufficient to cause the settled soot to burn off. These additives, however, cause an increase in fuel consumption and the ferric oxide remains suspensible for a very long time and is very problematic with respect to environmental pollution.
From DE-A-38 34 920 a method for removing soot from exhaust gases has become known according to which the soot particles are separated in a filter body with the help of an electric field. The combustion of the soot is made by arcs whose base points are situated in the area of the soot particles. Although such a method is suitable to clean the exhaust gases, it has been seen nevertheless that for cleaning the exhaust gases of a diesel engine of usual size and type such a high electric power is required that the method does not seem to be commercially viable.
From DE-A 37 23 544 a filter for cleaning exhaust gases has become known in which the combustible particles are to be oxydized by a corona. It is provided that the particles to be separated settle down at one of the electrodes which is arranged as a particle trap. A strong corona is to be formed between the electrodes, thus generating ionized oxygen. In such a device it cannot be prevented that strong spark discharges occur, which require a high electric power in addition to causing considerable stresses to the material. Such filters are not suitable for permanent operation in motor vehicles.
Furthermore it is known from EP-A- 332 609 of the present applicant to ionize the exhaust gases first and then guide them through a channel of a ceramic body, in which channel an electric field is generated substantially transversely to the direction of flow, thereby burning off at relatively high temperatures the soot particles deposited on the walls of the channel. In some possible applications it is difficult to generate such temperatures.
Other known devices are based on the principle that soot particles are burnt off from time to time after their deposit by supplying a respective quantity of heat or that the soot particles are agglomerated by an electric field, separated in a cyclone separator and then supplied to the mixture for combustion in the cylinders of the combustion engine.
The disadvantage of known solutions is due to the fact that on the one hand considerable quantities of heat have to be produced for burning the deposited soot and that according to the second method the cyclone separator requires a considerably complex mechanical setup and considerable energy quantities during its operation.
Processes are also known in which exhaust gases are guided through a porous ceramic body which retains the particles contained therein. Such processes are described, for example, in the following specifications: DE-A 36 38 203, EP-A 212 396, EP-A 270 990, GB-A 2 064 361, U.S. Pat. No. 4,662,911. Although the removal or destruction of soot particles is provided for by various measures, such filters have an unacceptably high flow resistance. Especially in the partial load area the formation of soot deposits may occur, leading to a considerable loss in pressure. Such concepts provide honeycombs or cellular filters which consist of long adjacent filter cells which preferably have a square cross section and which are
REFERENCES:
patent: 3440800 (1969-04-01), Messen-Jaschin
patent: 3979193 (1976-09-01), Sikich
patent: 4441971 (1984-04-01), Ishiguro
patent: 4662911 (1987-05-01), Hirayama et al.
patent: 4871515 (1989-10-01), Reichle et al.
patent: 4979364 (1990-12-01), Fleck
patent: 5074112 (1991-12-01), Walton
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