Power plants – Internal combustion engine with treatment or handling of... – Methods
Patent
1995-08-16
1998-09-29
Denion, Thomas E.
Power plants
Internal combustion engine with treatment or handling of...
Methods
60295, F01N 320
Patent
active
058132236
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The subject of the present invention is a process for the filtration and combustion of carbonaceous matter emerging from internal combustion engines. The invention more particularly relates to the regulation of the pressure drop occasioned in filters by the accumulation of soot in the filters.
2. Description of the Prior Art
During the combustion of motor fuels in internal combustion engines and especially during that of diesel oil in diesel engines, carbonaceous matter, hereinafter known as "soot", is formed which is supposed to be harmful both to the health of higher mammals and to the environment.
This soot is particularly abundant in the case of diesel engines and constitutes a handicap for this type of engine. The majority of the solutions envisaged consisting in changing the speed of the engine or its operating parameters come up against another constraint, that of not increasing the emission of carbon monoxide and/or of gases which are supposed to be toxic and mutagenic, such as nitrogen oxides.
Taking into account the above, the most effective technique seems to be to fit the exhaust silencer with a filter which is capable of stopping all, or at the very least most of, the soot formed by the combustion of the various fuels.
Success has thus been achieved in producing filters, especially made of cordierite, which make it possible to reduce soot emissions by at least 85% by mass.
The problem to be solved lies in the accumulation of this soot in the filters which causes, in the first place, an increase in the pressure drop and, in the second place, blocking to begin which leads to a fall in efficiency of the internal combustion engine.
Many a time have combustion techniques of the above soot been tested. It has thus been proposed to cause combustion of this soot intermittently either by electric heating or by heating by means of a fossil igniter fuel. The possibility has also been envisaged of drawing off the heat necessary for igniting this soot from the engine itself, by skillful management of the gas flows so as to heat the soot accumulated in the filter and ipso facto to cause its ignition (temperature of the order of 500.degree.-600.degree. C).
It has also been proposed to introduce ignition catalyst precursors into the various motor fuels, so as to lower the ignition temperature of the soot. These techniques, especially that of combining increasing the temperature of the soot using a suitable and transitory circuit of the exhaust gases with the addition of oxidation catalyst precursors, have made it possible at least partially to solve the problem.
However, on the one hand, the ignition temperature of the soot remains relatively high (of the order of 500.degree. C.) and, on the other hand, there is the risk of the intermittent and violent combustions causing a significant detrimental change in the filter and in its filtering abilities, either by cracking due to thermal shock or even by melting.
This detrimental change in the filters can take the form of a loss in ability to retain a high percentage of soot, while the initial percentage is sometimes considered to be insufficient.
SUMMARY OF THE INVENTION
For the above reason one of the aims of the present invention is to provide a combustion process of the soot which is as continuous as possible.
Another aim of the present invention is to provide a combustion process of the soot which does not produce violent, fierce and sudden ignitions leading to damaging of the filter. In order to achieve such a result, it is advisable to prevent, during the ignition phase, the temperature from reaching 1000.degree. C., advantageously 900.degree. C. and preferably 700.degree. C. in any part of the filter.
As it is difficult to measure the local temperatures, it was laid down that these latter restrictions corresponded to maximum gas temperatures, at the outlet of the filter, of not more than approximately 600.degree. C. ("approximately" in this instance means that zeros, which are in this inst
REFERENCES:
patent: 3370419 (1968-02-01), Ketzer
patent: 4462208 (1984-07-01), Hicks
patent: 4596277 (1986-06-01), Djordjevic
patent: 4655037 (1987-04-01), Rao
patent: 4693078 (1987-09-01), Dettling
patent: 5386690 (1995-02-01), Shustorovich
Barthe Philippe
Lemaire Jacques
Petta Dennis
Denion Thomas E.
Rhone-Poulenc Chimie
LandOfFree
Process for the filtration and combustion of carbonaceous matter does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for the filtration and combustion of carbonaceous matter, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for the filtration and combustion of carbonaceous matter will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-676785