Measuring and testing – Gas analysis – Solid content of gas
Patent
1989-11-02
1992-06-02
Williams, Hezron E.
Measuring and testing
Gas analysis
Solid content of gas
422 88, 422 91, G01N 3122
Patent
active
051176734
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
This invention relates to a process for determining the soot content of combustion gases, in particular the exhaust gases of internal combustion engines, which will form deposits on, i.e. blacken, a filter through which they are passed, this blackening of the filter being subsequently measured, and to a device for implementing this process.
DESCRIPTION OF THE PRIOR ART
Such a process is described in AT-PS 267 232, for example. In this instance a predetermined quantity of exhaust gas is passed through the filter, whose blackening is then measured. As the measuring equipment used must be suitable for a comparatively wide measuring range and the sensitivity of the equipment is not constant over the entire range, the precision of measurement depends on the soot content of the exhaust gas to be analyzed.
Another process for measuring exhaust gases and a device for implementing this process is presented in DD-PS 127 256. In order to compensate for differences in whiteness of a paper filter tape in the blackened area and in a reference area, the filter tape is subdivided into two parts along its length, one of which is continuously exposed to the samples whereas the adjacent part remains unexposed and is used for reference measurement. The samples of exhaust gas are taken quasi-continuously. The photoelectric evaluation unit has a mask with two openings, one of which is directed towards a part of the filter tape subject to the exhaust gas, whereas the other one is directed towards an unexposed part of the tape situated beside the former. For the same reasons as above the precision of measurement again depends on the soot content of the exhaust gas to be analyzed.
SUMMARY OF THE INVENTION
It is an object of the invention to propose a process of the above kind in which the precision of measurement will remain constant, regardless of the soot content of the exhaust gas to be analyzed.
In the invention this is achieved by determining by means of a suitable algorithm the volume of exhaust gas taken for each loading of the filter from the value of filter blackening obtained in a previous test, sampling being continued if the blackening of the filter is outside a specified range. In this manner the devices provided for measuring filter blackening may be used within a predetermined range, thus preventing the device characteristic from entering into the measurement.
It is recommended to operate in a range of relatively strong blackening since in this case differences in the whiteness of the filter material, e.g. a filtering paper, will not have any noticeable influence on the test result.
According to another aspect of the invention the exhaust volume may be determined upon its passage through the filter, and the resulting value may be combined with the value obtained for the blackening of the filter in a suitable computing device in such a way as to generate a signal proportional to the soot content in the exhaust gas. In this way the process may be organized in a simple manner which will also permit automation.
For further improvement of the precision of measurement it is proposed in a modified version of the invention that the pressure and/or temperature of the exhaust gas passing through the filter be measured and the volume of the exhaust gas passed through the filter during each measuring cycle be compensated for pressure and/or temperature.
In further development of the invention the proposal is put forward that the blackening of the filter be examined after a first sampling, and another sampling and measuring cycle be initiated automatically if the blackening of the filter is outside a specified range. With the use of a computing device this kind of process may easily be performed with conventional means.
It may further be provided that the blackening of the filter be continuously monitored throughout the sampling process by one or more sensors, and that sampling be terminated when the blackening is within a specified range. In this way one step of the procedure may be eliminated
REFERENCES:
patent: 4023930 (1977-05-01), Blunck et al.
patent: 4115067 (1978-09-01), Lushkow
Jaschek Alfred O.
Pfingstl Max
AVL Gesellschaft fur Verbrennungskraft-maschinen und Messtechnik
Miller Craig
Williams Hezron E.
LandOfFree
Process and device for determining the soot content of combustio 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 and device for determining the soot content of combustio, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process and device for determining the soot content of combustio will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2221715