Avl Gesellschaft Fur Verbrennungskraftmaschinen Und Messtechnik M.b.h.

Avl List Gmbh

Avl North America, Inc.

Other

Wolfgang Schindler

Peter W Krempl

William Martin Silvis

Norbert Kreft

Gerald Marek

Klaus-Christoph Harms

Leopold Faschingleitner

Erich J Schiefer

Franz Knopf

Christian Reiter

Erich Schiefer

Harald Grantner

Kurt Engeljehringer

Herbert Reingruber

Harald Koch

Tristan Reinisch

Wolfgang Singer

Geraki Marek

Aspects of the present disclosure are directed to a measuring device for determining a measured variable of a measuring gas by means of a photoacoustic method. In some embodiments, the measuring device includes a flow channel for the measuring gas having at least one feed line, a photoacoustic measuring cell and a discharge line. in such an embodiment, the measuring device further includes at least one acoustic filter member tuned to a useful frequency of the measuring cell, and at least one cavity resonator arranged on the flow channel.

Measuring device for ascertaining a measurand of a measurement gas

An exhaust emission analysis system is provided that includes an exhaust and dilution gas source respectively providing exhaust and dilution gases. A dilution unit includes exhaust and dilution gas mass flow controllers, fluidly connected to the exhaust and dilution gas sources. The mass flow controllers define a gas flow rate of gas from their respective gas source. A connection mixes the gases to provide a diluted exhaust gas having an incorrect dilution ratio. A water measurement device measures the water content of the exhaust gas. A water content dilution signal is sent from the water measurement device to a control device. An adjustment factor is calculated by the controller and a flow rate command signal is sent from the controller, to the exhaust gas mass flow controller to adjust the gas flow rate of the exhaust gas and provide a corrected dilution ratio at the connection.

Engine exhaust emissions measurement correction

An exhaust sampling system is provided that includes a sampler having a sample inlet for receiving an exhaust gas sample. The sampler includes a mixer for receiving the exhaust gas sample and a diluent to produce a diluted exhaust gas. The exhaust sampling system includes first and second dilution gas flow devices. The first and second dilution gas flow devices are fluidly connected to one another at a second junction. Any diluent provided by the first and second dilution gas flow devices intermingles with one another prior to reaching the mixer. A diluted sample flow meter is arranged downstream from the mixer for receiving the diluted exhaust gas. In one example, diluent flow from the first and second dilution gas flow devices intermingles before being introduced to the mixer. In another example, diluent flow from the first dilution gas flow device is leaked out of the second dilution gas flow device in a controlled manner to achieve a desired diluent flow into the mixer. The example exhaust sampling system does not require a measurement of the flow of exhaust gas sample into the system. Instead, the flow of the diluted exhaust gas is measured by the diluted sample flow meter. And, the flow of diluent through the first and second dilution flow meters is measured and the net flow through the first and second dilution flow meters is subtracted from the flow of the diluted exhaust gas through the diluted sample flow meter.

Particulate sampler and dilution gas flow device arrangement for an exhaust sampling system

A measuring chamber for photo-acoustical sensors for the continuous measurement of radiation-absorbing substances, in particular of radiation-absorbing particles, in gaseous samples includes at least one entry and at least one exit for the samples, a tube section with microphone that allows for the flow-through of the sample in longitudinal direction, and at least one entry and exit point for a laser beam that is aligned with the tube section, and whereby these entry and exit points are both arranged at a distance from the measuring tube by at least one chamber with a cross-sectional area that is expanded relative to the tube section. To prevent soiling of the windows at the points of entry of the radiation into the cell and to slow down the deposition of the particles of the measured aerosol, whereby long-term, high-sensitivity operation of the measuring cell is possible, two entries () are envisioned at two ends of the tube section () that are opposite relative to each other and at least one exit () that is arranged at a location which is centered between the entries ().

Measuring chamber for photo-acoustical sensors

The invention relates to a method for determining the non-volatile component of aerosol particles in a gas sample, especially in the exhaust gas of internal combustion engines, where the aerosol particles are deposited on an oscillating sensor () of at least one crystal microbalance (), and the change in at least one oscillation parameter of the oscillating sensor is employed as measurement variable. According to the invention the oscillating sensor () of at least one crystal microbalance () is maintained at a temperature of more than 200&#xb0; C. during deposition of the aerosol particles, and preferably between 250&#xb0; C. and 350&#xb0; C.

Method and apparatus for determining the non-volatile component of aerosol particles in a gas sample

A particulate sampler is provided for conveying exhaust gas from exhaust gas source to analysis equipment. The particulate sampler includes a probe for receiving the exhaust gas and a transfer tube for conveying the exhaust gas from a tailpipe to a mixer. The mixer mixes the exhaust gas and a dilution gas from a dilution source. A dilution tunnel mixes and conveys the exhaust gas and dilution gas from the mixer to analysis equipment such as a filter or gas analyzers. A flow pulsation cancellation device includes an actuator in communication with at least one of the tailpipe, probe, transfer tube, mixer, and dilution tunnel for introducing a canceling pressure pulse to minimize the effects of pressures pulses present from the tailpipe within the sampler. The actuator may be a moveable membrane or a fluid flow control valve. Pressure sensors are used to measure the pressure of the undiluted and diluted exhaust gas, and a controller determines the desired canceling pressure pulse based upon the measured pressures.

Active pulsation cancellation device for diesel particulate sampling systems

An exhaust emission analysis system is provided that includes an exhaust and dilution gas source respectively providing exhaust and dilution gases. A dilution unit includes exhaust and dilution gas flow devices, such as mass flow controllers, fluidly connected to the exhaust and dilution gas sources, respectively. The metering device in the mass flow controllers defines a gas flow rate of gas from its respective gas source. The gas flow devices are fluidly connected at a connection that mixes the gases to provide a diluted exhaust gas having an incorrect dilution ratio. A water measurement device such as an analyzer measures the water content of the exhaust gas, preferably subsequent to dilution. A water content dilution signal corresponding to the water content in the exhaust gas is sent from the water measurement device to a control device. An adjustment factor is calculated by the controller and a flow rate command signal is sent from the controller corresponding to the adjustment factor, preferably, to the exhaust gas mass flow controller to adjust the gas flow rate of the exhaust gas and provide a corrected dilution ratio at the connection. Correction of the diluted exhaust gas ratio may also be provided to particulate samplers according to the above principles.

A process is provided for measuring the opacity in gases, especially in exhaust gases or in the atmosphere, at or near the maximum of the eye sensitivity in the green wavelength range with a central wavelength lying between 550 and 570 nm. In order, in a simple manner, to separately determine the components which are responsible for clouding in the visible wavelength range, or to make a correction possible by taking into consideration further components that have an effect in the visible range, the opacity in at least one second wavelength range which is located in the spectral between 200 nm and 2&mgr;, and which overlaps at most slightly with the first wavelength range is additionally measured.

Process and apparatus for measuring the opacity in gases

For the indirect identification of the mass flow of a specimen fluid stre the specimen fluid stream is mixed with a dilution fluid stream to form an total fluid stream that is to be investigated in view of specific constituents of the specimen fluid stream. The mass flow of a specimen fluid stream is identified from the difference between the measured mass flows of the dilution fluid stream and the total fluid stream. In order to reduce the possibilities of error in the setting of a defined dilution ration, the mass flows of the dilution fluid stream and the total fluid stream are calibrated relative to one another, to which end one of the calibration measurements is not undertaken at the respective fluid stream but is separately undertaken at the specimen fluid stream.

Method and apparatus for the indirect identification of mass flow

A method and device for delay-free measurement of the air/fuel ratio of combustion systems, especially internal combustion engines, by measuring individual components of the fuel, the ambient air used for fuel combustion, and the exhaust gas, wherein the water vapor concentrations of the exhaust gas and, preferably, the ambient air or the gas supplied for fuel combustion are measured, and wherein the air/fuel ratio are computed by the obtained values and data on fuel composition.

Method and a device for measuring the air/fuel ratio of an internal

In conventional methods of quantitative hydrocarbon analysis in gaseous sles by means of infrared transmission, systematic inaccuracies may be found which are caused by changes in the composition of the components contained in the sample. Such inaccuracies typically amount to 10 to 30% of the measured value, with occasional rises of up to 100%. In order to eliminate this disadvantage the invention proposes that for determining the total mass of gaseous and condensed hydrocarbons radiation be used with a frequency band whose integral infrared absorption has approximately the same value for each of the main hydrocarbons present.

Method for quantitative analysis of hydrocarbon

In order to eliminate equipment-generated fluctuations during the periodic determination of a quantity to be measured which is effected by forming the difference between a measuring signal which has been altered relative to a source signal by the measurement variable and a reference signal which has remained unaffected relative to the source signal by the measurement variable, a base signal level is determined for each measuring cycle as the difference between the reference level and a zero level in the absence of a source signal, subsequent to which each actual reference signal level and each measuring signal level is compensated with the previously determined reference signal level. By amplifying the compensated reference signals prior to difference formation and standardizing the signal difference to the base signal level, a high degree of accuracy may be achieved even if the attenuations of the measuring signal caused by the quantity to be measured are very small.

Method for the periodic determination of a quantity to be measured,

A test volume and a reference volume are irradiated by separate beams of an infrared source, and the two beams are subsequently fed to a detector in periodical alternation. The time constant of the detector is small compared to the period of this alternation. From the measured differences in intensity the masses of the absorbing components of a sample in the test volume are determined. During each period the value of the detector signal is sampled by an evaluation unit at least once while either the test beam or the reference beam is being present at the detector. For separate determination of different sample components, radiation of different defined frequency bands is fed to the detector during each period, and the intensity of the test beam is determined at each of the different frequencies whereas that of the reference beam is determined at one of these frequencies at least.

Method of determining masses of absorbing components of a sample in a

A gaseous sample and a reference volume are traversed by electromagnetic iation and the absorption caused by the sample, as given by the difference between the radiation intensities after passage through the sample and the reference volume, is measured and used as a measurement value. By means of radiation of a wavelength in the range between 3.8 and 4.15 .mu.m, the specific mass of particles characterized by broadband absorption--especially graphitic particles--is determined; by means of radiation of a frequency band centered in the wavelength range of 3.35 to 3.5 .mu.m, whose 3 dB bandwidth does not exceed 0.3 .mu.m, the specific total mass of aerosol particles is determined, and by the additional measurement of the resonance absorption at a wavelength in the range of 3.35 to 3.5 .mu.m the percentages of both graphitic and organically soluble particles are determined separately. In a device for the implementation of the method a beam splitter transmits the radiation of a common radiation source to the sample and the reference volume; by means of a deflection unit the partial beams are reunited and transmitted to an evaluation unit in front of a common detector. With the aid of two transparent plates with parallel faces which are inclined against the incident beam at the Brewster angle, and are inserted in the beam splitter and in the deflection unit, the partial beams are polarized differently; as selector unit a rotatable polarization analyzer is used.

Method and device for continuous measurement of the mass of aerosol

For a continuous measurement of the mass of absorbing particles in a gaseous sample, the sample is traversed by electromagnetic radiation of a wavelength greater than the mean radius of the particles. The difference in absorption for at least two frequencies is determined and appointed to the particle mass sought after.

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Graz, Austria

Wolfgang Schindler