Classifications

• • 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
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
  • G01M15/00—Testing of engines
  • G01M15/04—Testing internal-combustion engines
  • G01M15/10—Testing internal-combustion engines by monitoring exhaust gases or combustion flame
  • G01M15/102—Testing internal-combustion engines by monitoring exhaust gases or combustion flame by monitoring exhaust gases
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/0004—Gaseous mixtures, e.g. polluted air
  • G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
  • G01N33/0011—Sample conditioning
  • G01N33/0018—Sample conditioning by diluting a gas
• • 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
  • G01N2001/2255—Sampling from a flowing stream of gas in a vehicle exhaust with dilution of the sample

Definitions

• the invention relates to a system for taking exhaust samples of internal combustion engines with an exhaust gas duct, which is fluidly connected to an exhaust gas source via an exhaust gas inlet, an air duct into which ambient air can be sucked via an air filter, a mixing zone which is arranged downstream of an outflow cross section of the exhaust gas duct, a dilution tunnel, through which an exhaust gas-air mixture flows, wherein a Ausströmquer bain the exhaust passage is arranged substantially concentric in the air passage and downstream of the Ausströmqueritess the exhaust passage in the dilution tunnel, an annular aperture is arranged.
• Such systems are known, for example, by the term CVS system (constant volume sampling).
• CVS system constant volume sampling
• the exhaust gas is always admixed with so much air that a constant total volume flow of the air-exhaust mixture is formed.
• the samples taken from these systems in bags are analyzed below for their pollutant content.
• the carbon dioxide, the carbon monoxide, hydrocarbon, the nitrogen oxide content and the particle load are measured.
• the type of measurements is regulated by law, for example, by the ECE guideline R 83 for the European area or the Code of Federal Regulations Act No. 40 for the US area.
• DE 10 2009 015 188 AI a system for the removal of exhaust gas samples is described, which can be connected to two different exhaust gas sources, so that via a system both the Particle load of diesel engines and gasoline engines can be measured.
• the exhaust duct of the system which comes from the diesel engine, ends concentrically in the air duct upstream of a diaphragm. In the region between the outlet cross-section of the exhaust gas duct and the diaphragm, a mixing zone is formed, in which the exhaust gas mixes with the air.
• the task arises to develop a system with which a representative sampling is ensured in accordance with the law by the formation of areas with poor exhaust gas mixing is avoided.
• the system should be inexpensive to produce and operate, in particular delivery pumps with relatively low power to promote the two gas streams are sufficient.
• the means for flow deflection are formed by a body which has a spherical zone and is arranged concentrically in the dilution tunnel.
• the ball zone By the ball zone, the pressure loss during the deflection of the exhaust gas flow is not substantially increased, so that the driving pressure gradient and thus the power consumption of a feed pump need not be increased. Also, this body achieved particularly good mixing of the two gas streams.
• the spherical zone is a hemisphere. This design gave particularly good results in the homogenization of the mixture and at the same time reducing the pressure loss.
• the surface of the spherical zone is electropolished. Furthermore, it is prevented that subsequently dissolving by the deflection means particles falsify the measurement result.
• this has a central hole. Through this hole, the formation of a pressure loss significantly increasing stagnation point is avoided without significantly worsen the mixing.
• the spherical zone or the aperture are heated. This is realized particularly simply by arranging a heating foil on the downstream surface of the spherical zone or the diaphragm so that it is not directly exposed to the exhaust gas flow but is protected by the upstream surface. This avoids the formation of condensate on the surfaces that have flowed on, which in turn leads to a reduction in deposits.
• the flow cross section of the orifice corresponds to 1.2 to 1.8 times the cross section of the means for flow deflection.
• the distance of the means for flow deflection from the Ausströmquerites the exhaust passage is one third to one fifth of the difference of the diameter of the air duct and the diameter of the exhaust passage. This ensures that the pressure loss during the inflow of the exhaust gas into the air flow is not too large. On the one hand, sufficient exhaust area is made available to the exhaust gas flow and, on the other hand, the deflection angle is sufficiently high to generate turbulence and thus to prevent stratification.
• an excessive pressure loss when flowing through the aperture is prevented by the distance of the means for flow deflection to the aperture is one third to one fifth of the diameter of the air channel.
• a sufficient surface for the exhaust gas-air mixture is provided and on the other hand generated by the relatively close successive deflection in opposite directions turbulence.
• the means for flow deflection are formed by a plurality of symmetrically arranged to the central axis exhaust ducts.
• each exhaust pipe Preferably, four exhaust pipes are arranged offset by 90 ° to each other. This creates a sufficiently constant introduction of the exhaust gas over the entire cross section, but with little design effort. Also, this design is easy to assemble.
• the four exhaust pipes extend in the immediate vicinity of the exhaust duct or in the exhaust duct initially parallel to the central axis and are continuously bent in the following course outside the exhaust duct from the central axis. This continuous bending reduces the pressure losses.
• the outlet cross-sections of the exhaust pipes to the central axis of the dilution tunnel at an angle of 30 ° to 80 °, which on the one hand sufficient deflection to increase the mixing is ensured and on the other hand, the pressure loss is maintained at the meeting of the two gas streams within reasonable limits, so that the total pressure increase of the blower to promote the gas flow need not be further adjusted.
• a particularly simple attachment and assembly results when the means for flow deflection are fastened to the panel via at least one, preferably three holders, since the assembly takes place in one step with the panel assembly.
• a system is provided for taking exhaust gas samples from internal combustion engines, which ensures that representative samples can be taken from the dilution tunnel, since a very good mixing of the two gas streams 5 is ensured.
• the system is inexpensive to produce and operable, since the installation is simple and relatively small conveyor fan can be used because additional pressure losses are kept small.
• Figure 1 shows schematically a system according to the invention for the removal 15 of exhaust gas samples in side view.
• Figure 2 shows an enlarged view of a detail of the system of Figure 1 in the region of the mixing zone in three-dimensional representation.
• FIG. 3 shows an alternative embodiment of the mixing zone according to the invention in a three-dimensional representation.
• the system according to the invention for taking out exhaust gas samples from internal combustion engines for diesel or gasoline engines consists of an exhaust gas inlet 10, via which an exhaust gas channel 12 is fluidically connected to an exhaust gas source 14 which is formed by an internal combustion engine of a motor vehicle.
• This exhaust gas channel 12 has an end 16 with an outflow cross section 30 18, which opens concentrically within an air channel 20.
• this air duct 20 has an opening 22 in its boundary wall 24, through which the exhaust duct 12 projects perpendicularly into the air duct 20.
• the exhaust duct 12 Around concentric open in the air duct 20, the exhaust duct 12 has a 90 ° deflection.
• the air duct 20 Upstream of the exhaust duct 12, the air duct 20 has an inlet 26, on which a first air filter 28, which usually comprises three filters, is arranged, through which air can be sucked into the air duct 20.
• the deflection of the exhaust duct 12 is designed so that the outflow direction of the exhaust gas is directed to the air filter 28 opposite side, so that the air flow and the exhaust flow at Ausströmquerites 18 of the exhaust passage 12 have a common flow direction substantially parallel to the central axis of the air channel 20th runs.
• means 32 are arranged for deflecting the exhaust gas flow behind the Ausströmquerites 18 of the exhaust passage 12. These can be structurally designed differently, as apparent from the following description of Figures 2 and 3. Regardless of the design of the means 32, these serve to divert the exhaust gas flow in the direction of the air flow, ie with a component in the radial direction of the air channel 20 into the air flow, whereby turbulence occurs and an improvement of the mixing occurs.
• a diaphragm 34 is arranged, through which the freely flow-through cross-section of the air channel is narrowed, so that the flow rate increases and additional turbulence occurs.
• These turbulence zones form a mixing zone 36 in which as complete a mixing as possible of the exhaust gas stream takes place in the air stream and which extends to behind the orifice 34.
• This mixing zone 36 is followed by a dilution tunnel 38, in which a uniform flow of the exhaust gas-air mixture without stratification is present.
• a sampling probe 40 for taking a sample from the mixed stream.
• the sample stream recorded via the sampling probe 40 can either be fed via a heatable particle filter to a flame ionization detector, via which the hydrocarbons in the exhaust gas are determined in order to determine the proportions of nitrogen oxides, carbon dioxide and carbon monoxide in the exhaust gas.
• the particulate emissions are removed and fed to a particle measuring device. The promotion of the analysis flows takes place in each case via separate pumps, not shown.
• the remaining mixed gas stream passes from the dilution tunnel 38 to a controllable feed pump 42, which is intended to generate a sufficient pressure for conveying the air and the exhaust gas.
• the mixed gas stream is ejected.
• a Venturi nozzle in front of the feed pump for setting the desired flow rate.
• the gas flow is measured by the feed pump at a constant temperature and pressure or constant flow rate.
• the exhaust gas is diluted in a defined ratio with the ambient air. Sampling takes place in each case proportionally to the flow of the feed pump 42.
• sampling systems with variable dilution and positive displacement pump are just as well known as dilution systems with critically flowed Venturi tube, as described for example in ECE Guideline R83.
• the arrangement of the flow controllers, valves, flow, pressure and temperature measuring devices used in these systems is also known and varies depending on the system used, so that these possibilities of regulation are required here as expertise.
• the present invention is suitable for all these forms of sampling. However, the results of the sampling of such a plant are indeed representative only if it is ensured that the most homogeneous flow possible at the sampling points
• This hemisphere 44 is located at a distance of 45 mm from the outflow cross section 18 of the exhaust gas channel 12 and has a diameter of approximately 95 mm, while the outflow cross section of the exhaust gas channel 12 is approximately 90 mm.
• the hemisphere 44 in turn is about 70 mm away from the aperture 34, the free flow diameter is about 150 mm.
• the hemisphere 44 further has a central hole 46 which prevents the formation of a stagnation point and thus also avoids further pressure loss.
• the surface of the hemisphere 44 is electro-polished on its side facing the flow on its opposite side coated with a heating foil, so that condensation of exhaust gas is avoided.
• the hemisphere 44 is attached via three struts 48 to the diaphragm 34, so that the hemisphere 44 can be pre-assembled in a simple manner with the diaphragm 34 and can be used together with the diaphragm 34 concentric with the dilution tunnel 38 in this.
• FIG 3. An alternative embodiment is shown in FIG 3.
• the outflow 18 of the exhaust duct 12 are four offset by 90 ° symmetrically mutually arranged exhaust pipes 50 which are initially parallel to the flow direction of the exhaust passage 12 and are bent radially outward beyond the end 16 of the exhaust passage 12, so that the tubes 50 in their course in the flow direction steadily remove from the central axis.
• the outlet cross sections of the exhaust pipes 50 close to the central axis of the dilution tunnel 38 at an angle of 45 °.
• the attachment of these exhaust pipes 50 is carried out in advance on a ring 52 which is attached to the exhaust duct 12 during assembly.
• an attachment via struts on the panel 34 is feasible.
• This embodiment of the means 32 for flow deflection ensures an axisymmetric inflow of the exhaust gas flow at an angle in the air flow, so that the exhaust gas flow is forced a radial component, which causes the vortexes to arise in a direction that the vortex due to the constriction the aperture 34 is opposite, so that large turbulence arise, which have a very good mixing of the two gas streams result.
• the constant deflection ensures low pressure losses.
• Both versions are accordingly suitable for improving the mixing and homogenization of the exhaust gas stream, so that a representative sampling is made possible. This leads to better test results in the analysis of pollutant loads, without the performance of the feed pumps must be increased because existing pressure losses are kept as small as possible.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Combustion & Propulsion (AREA)
• Analytical Chemistry (AREA)
• Biochemistry (AREA)
• General Health & Medical Sciences (AREA)
• Immunology (AREA)
• Pathology (AREA)
• Medicinal Chemistry (AREA)
• Food Science & Technology (AREA)
• Biomedical Technology (AREA)
• Molecular Biology (AREA)
• Sampling And Sample Adjustment (AREA)

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• 2012
  • 2012-03-14 DE DE102012102137A patent/DE102012102137A1/de not_active Ceased
• 2013
  • 2013-03-12 CN CN201380019963.XA patent/CN104220860B/zh not_active Expired - Fee Related
  • 2013-03-12 KR KR1020147028680A patent/KR101736082B1/ko not_active Expired - Fee Related
  • 2013-03-12 JP JP2014561412A patent/JP6072086B2/ja not_active Expired - Fee Related
  • 2013-03-12 EP EP13710827.0A patent/EP2825863B1/de active Active
  • 2013-03-12 IN IN7671DEN2014 patent/IN2014DN07671A/en unknown
  • 2013-03-12 US US14/384,690 patent/US9952124B2/en active Active
  • 2013-03-12 WO PCT/EP2013/054973 patent/WO2013135678A1/de not_active Ceased

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