Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
  • G01N15/06—Investigating concentration of particle suspensions
  • G01N15/0606—Investigating concentration of particle suspensions by collecting particles on a support
  • G01N15/0618—Investigating concentration of particle suspensions by collecting particles on a support of the filter type
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
  • B01D46/42—Auxiliary equipment or operation thereof
  • B01D46/44—Auxiliary equipment or operation thereof controlling filtration
  • B01D46/446—Auxiliary equipment or operation thereof controlling filtration by pressure measuring
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
  • B01D46/42—Auxiliary equipment or operation thereof
  • B01D46/44—Auxiliary equipment or operation thereof controlling filtration
  • B01D46/46—Auxiliary equipment or operation thereof controlling filtration automatic
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N1/00—Sampling; Preparing specimens for investigation
  • G01N1/02—Devices for withdrawing samples
  • G01N1/22—Devices for withdrawing samples in the gaseous state
  • G01N1/2247—Sampling from a flowing stream of gas
  • G01N1/2252—Sampling from a flowing stream of gas in a vehicle exhaust
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2279/00—Filters adapted for separating dispersed particles from gases or vapours specially modified for specific uses
  • B01D2279/30—Filters adapted for separating dispersed particles from gases or vapours specially modified for specific uses for treatment of exhaust gases from IC Engines
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
  • F01N2560/00—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
  • F01N2560/05—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being a particulate sensor
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
  • F01N2560/00—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
  • F01N2560/08—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being a pressure sensor
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N1/00—Sampling; Preparing specimens for investigation
  • G01N1/02—Devices for withdrawing samples
  • G01N1/22—Devices for withdrawing samples in the gaseous state
  • G01N1/2202—Devices for withdrawing samples in the gaseous state involving separation of sample components during sampling
  • G01N1/2205—Devices for withdrawing samples in the gaseous state involving separation of sample components during sampling with filters

Definitions

• the invention relates to a method for automatically operating a measuring device for Parti kelunk in gases, in particular the soot particle measurement in the exhaust gas of internal combustion engines, in which determines several times in time-limited individual measurements particle-related variables from the darkness of a filter paper and caused by the sample gas flow differential pressure on the internal Metering be monitored, below a primary threshold for the differential pressure, the individual measurement automatically aborted and an error message is issued.
• soot particle measurement mainly but not exclusively of explosion engines, measuring instruments have been used for a long time and very successfully in which a gas containing the particles is passed over a filter paper for a certain time. The particles are filtered out on the filter paper and finally the blackening of the paper with soot particles is measured.
• a gas containing the particles is passed over a filter paper for a certain time.
• the particles are filtered out on the filter paper and finally the blackening of the paper with soot particles is measured.
• For fully automated measurements which can be carried out without monitoring by personnel, but for a variety of causes can lead to critical conditions in the tests, which can result in an error message and / or a termination of a measurement.
• test settings can repeatedly occur where too many particles are deposited during a measurement. For example, such errors or warnings may occur or increase the likelihood of these error messages if, due to inadequate maintenance or unexpected additional system contamination from the measurements themselves, the flow rate is too high
• the same effects also occur when high negative pressures occur in the system during the measurement, or when the flow rates are reduced by pressure resonance, or when the probe or a sample gas loop ch too heavily contaminated or even "clogged" is.
• errors can also occur if the hardware, such as the pump or a solenoid valve, no longer works perfectly correct, but otherwise are only latently defective.
• the passage of a secondary threshold value above the primary threshold value is monitored for the differential pressure and the individual measurement is automatically interrupted if this secondary threshold value is undershot, the fulfillment of at least one predefined criterion is checked, whereby if this criterion is not met, the individual measurement is aborted with an error message, while a measured value is output when the criterion is met.
• a current threshold value is predetermined by multiplying a basic threshold value by the ratio of current pressure to a reference pressure, and an immutable third minimum threshold value is specified in addition to the primary and secondary threshold value which falls short of the individual measurement in any case with an error message is aborted.
• the minimum threshold between 1.5 and 2 kPa, the secondary threshold at about 5.5 kPa and the primary threshold at about 4 kPa can be specified.
• the quantity of measuring gas sucked in via the filter is checked as a criterion.
• an error message is always output in an amount of up to 100 ml, the fulfillment of at least one further criterion is checked for an amount between 100 ml and 500 ml, and a measured value is output in any case for an amount greater than 500 ml.
• the presence of an internal drift evaluation of the measurement signals is checked as a criterion.
• An advantageous embodiment of the invention provides here that, in the case of an inactive drift evaluation, only the primary threshold is considered a criterion and that falls below this threshold always an error, but at or above this threshold always a reading is output.
• An advantageous variant of the method according to the invention further provides that it is checked whether the internal drift evaluation of the measurement signals is activated or not, and that in the case of an inactive drift evaluation and a quantity of sample gas of less than 500 ml an error message is issued, and that at Fulfillment of at least one criterion in addition still the paper blackening is used as a criterion.
• a measured value is preferably output when there is a blackening of at least 0.2, and an error message is output when the density is less than 0.2.
• FIG. 1 shows a diagram of a simplified basic measuring sequence and the differential pressure and flow values occurring therein.
• FIG. 2 shows the definition of the threshold values for the negative pressure caused by the measuring gas flow itself and its throttling at a diaphragm measuring section for a typical functional sequence the thresholds for the measurement abort and / or for the output of an error message when falling below the error limit, and
• Fig. 3 is a flow chart of a typical functional sequence according to the present invention.
• a measuring gas containing particles flows over a filter paper for a certain time. Particles are filtered out on the filter paper and finally the blackening of the paper with soot particles is measured.
• the sample gas flow is usually determined by the differential pressure drop across an orifice and the relative pressure at the site, but can also be measured directly.
• an evaluation by means of the duration of the gas flow can also be carried out as a parameter, where, for example, at a nominal gas flow of 10 liters per minute, this corresponds to a measurement gas flow time of 6 seconds.
• the passing of a secondary, as well as the primary threshold value monitored above the primary threshold threshold value for the differential pressure and automatically falls short of this secondary threshold, the individual measurement.
• the secondary threshold is set at about 20 to 50% above the primary threshold.
• FIG. 2 shows an advantageous expanded definition of the threshold values for the negative pressure produced at a diaphragm measuring section by the sample gas flow itself and its throttling and the threshold values or triggering limit values for the measurement abort and / or for the output of an error message if the error limit is undershot.
• the error range is the range where an error is always output, either because a rapid event has caused the flow differential pressure reading to fall below that value or the differential pressure caused by the flow did not exceed that value from the start.
• the range of checks between the 40 and 55 mbar values defined, for example, is the area in which the existing measurement data is checked as to whether sufficient and sufficiently significant measurement data are available to allow a correct calculation of measured values from this existing data.
• the primary and secondary thresholds are variable, taking into account the absolute pressure and / or a simulation pressure in altitude simulations in these thresholds, also the check and error range are variable. However, it can also be advantageously defined a "lowest threshold”, below which always an error is issued, which are therefore never fallen below can cause without an error message.
• the illustrated “third threshold” or “lowest threshold” replaces the "primary threshold” when the primary and secondary thresholds are variably defined
• the ambient absolute pressure must either be measured or read by a sensor, or parameterized Likewise, any “simulation pressure value” must be read or communicated to the measuring instrument.
• the primary threshold value (1) or the "lowest threshold value" according to FIG. 2 is undershot by the measured differential pressure, eg because the pump is defective, or because an existing safety filter is completely blocked "is, then also always an error message is issued.
• the fulfillment of at least one predefined criterion is automatically checked. If this criterion is not met, the individual measurement is aborted with an error message. But if the predefined criterion is met, then a measured value is output. An error is now only output if there is insufficient data for the correct calculation and / or evaluation, or if the primary threshold value is either exceeded very quickly in time or if the exceeding of the primary threshold value is so great that this constitutes a risk for one Defective of the device or the test stand would entail.
• the automatic check may be based on whether the type of measurement at all allows an evaluation of the data available at the time the measurement was interrupted. For example, no such evaluation is performed when deactivating the white balance check - alternatively, the separate would also be or additional evaluation of the black level drift or temperature drift measurements as further additional or alternative criteria possible - ....
• a check can be made as to whether the flow rate has reached an upper threshold value, which usually or generally allows an evaluation of the measured data, or whether the paper blackening at the time of termination has exceeded a certain threshold value and whether the flow rate (the aspirated sample gas volume or alternatively the measuring time) has reached a minimum value. If this measured value data permits a correct evaluation of the filter blackening number (FSN), a measured value is displayed; if not, an error message is output.
• FSN filter blackening number
• the secondary threshold of e.g. 55 mbar is active, and if it falls below the measurement will be aborted and an evaluation of the data will be made. Depending on the data situation, a measured value or an error message is output. If, during the measurement, or even at the start of the measurement, the primary threshold of 40 mbar is exceeded, an error message is always output.
• the internal drift evaluation - in particular the white value monitoring of the measuring system - of the measuring device is deactivated, or if other measures with an increased drift (although this is still within the device specifications) are to be expected, then when too low a gas flow occurs during the parameterized measuring sequence always outputs an error message (either a flow error or a differential pressure error). Under these circumstances, if a measured value drift is actually present, an incorrect evaluation of the data could be possible.
• the gas flow may also be injected directly with e.g. a mass flow meter is measured, or as a further alternative, the duration of the gas flow can be checked as a parameter.
• the minimum amount of gas preferably a value of 500 ml (or alternatively about 3 sec duration).
• an evaluation of the data is always carried out, since usually a sample gas flow of 500 ml is always sufficient to ensure a data evaluation within the device specifications.
• the primary and secondary threshold values can be advantageously represented as functions of the ambient pressure on the measuring system, such that these two pressure thresholds of 40 mbar and 55 mbar (or more generally the primary and secondary pressure threshold) are based on a sample gas flow at a reference pressure of 100 kPascal and at a reference temperature of preferably 25 ° C (298 Kelvin).
• these differential pressure values which are caused as a result of the sample gas flow, for example, by the pressure drop at a dynamic pressure diaphragm, but also refer to a different reference temperature, for example to 15 ° C.
• reference pressures and reference temperatures should always be in the range of 30 to 200, but preferably in the range of pressures of 50 to 110 kPascal and temperatures of 230 to 400 Kelvin, preferably 270 to 370 Kelvin.
• the reference temperature is fixed at 25 ° C (298 Kelvin) in the formula above and thus not visually contained (or indirectly included as factor Tref / Tref).
• Pref is the reference pressure (100 kPascal, for example).
• the ambient pressure and / or the simulation pressure are either entered as values or read in analog or digital, or parameterized.
• the ambient pressure on or in the device is measured by an absolute pressure sensor.
• the surface flow velocity at the filter paper surface in the measuring device remains within a certain range.
• the defined “fixed thresholds” At typical ambient pressures of 50 to 110 kPascal, this is possible with the defined "fixed thresholds", but at an ambient pressure of 50 kPascal, the measured value is close to the threshold value of 55 mbar from the very beginning, but on the other hand, the diaphragm pump used is "a constant volume”. - Regardless of the ambient pressure - promotes the thresholds can be adjusted when the device, the ambient pressure and the relative pressure and relative pressure on the filter paper rel. to the environment, or if this data of the ambient pressure is communicated to the meter.
• a similar methodology may also be used when sampling in altitude and pressure simulation experiments on systems operating at sub-atmospheric pressure levels, but the gauge itself operates at normal ambient pressure.
• the measuring device can be informed of the simulation pressure or read in on the device.

Landscapes

• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• General Physics & Mathematics (AREA)
• Pathology (AREA)
• Analytical Chemistry (AREA)
• Biochemistry (AREA)
• General Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Immunology (AREA)
• Physics & Mathematics (AREA)
• Dispersion Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Biomedical Technology (AREA)
• Molecular Biology (AREA)
• Measuring Fluid Pressure (AREA)
• Sampling And Sample Adjustment (AREA)
• Measuring Volume Flow (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=42244820

Family Applications (1)

Country Status (6)

Cited By (2)

Families Citing this family (9)

Citations (8)

Family Cites Families (7)

• 2010
  • 2010-03-25 AT AT0019910U patent/AT11332U3/de not_active IP Right Cessation
• 2011
  • 2011-03-15 US US13/637,276 patent/US20130060485A1/en not_active Abandoned
  • 2011-03-15 WO PCT/EP2011/053890 patent/WO2011117115A1/de not_active Ceased
  • 2011-03-15 CN CN201180015671.XA patent/CN102844653B/zh not_active Expired - Fee Related
  • 2011-03-15 JP JP2013500431A patent/JP5689947B2/ja not_active Expired - Fee Related
  • 2011-03-15 DE DE112011101040T patent/DE112011101040A5/de not_active Withdrawn

Patent Citations (8)

Also Published As

Similar Documents

Legal Events