Classifications

• • 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
  • G01M15/108—Testing internal-combustion engines by monitoring exhaust gases or combustion flame by monitoring exhaust gases using optical methods
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
  • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
  • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
  • G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
  • G01N21/3504—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light for analysing gases, e.g. multi-gas analysis

Definitions

• OBD on-board diagnosis
• a signal lamp on the dashboard is shaded and an error code is saved.
• the malfunction found should be localized, described as precisely as possible and the information stored so that it can be read out by the repair workshop via a standardized interface for rapid identification and repair of the fault.
• Registrations IV and 121 deal in the narrower sense with neighboring subject areas and are therefore dealt with in more detail.
• the IM patent describes an infrared measuring device which monitors the operating state of the catalytic converter in such a way that it looks sideways into the catalytic converter and through a
• Opening determines the gas atmosphere in the catalytic converter.
• 121 shows a measuring device which can be clocked quickly and which enables a temporal resolution of 0.1-0.2 s by shading several infrared cells in series. Both sources give no information for the continuous measurement of pollutant emissions behind the catalytic converter in the exhaust system.
• Future vehicles will have an integrated OBM system for exhaust gas analysis. Certain portions of the exhaust gas are analyzed. An error in the combustion system can be concluded by comparing current concentration curves with stored target characteristics. A warning is triggered when a history saved for the respective car type and found as .good * is persisted, repeated and clearly exceeded. -Long-lasting "means for a longer time,” repeated “means that the exceeding does not occur once, but several times, and” unambiguous "means that the concentration is the given one
• the measurement of the exhaust gases is made difficult by the fluctuating conditions in the motor vehicle.
• a measuring system must adhere to the general tolerance limits and requirements applicable to a motor vehicle, and on the other hand, the exhaust gas properties pressure, humidity, temperature and flow are subject to strong fluctuations which influence the concentration measurement.
• microsystem components are required both for the exhaust gas treatment and for the measurement of the exhaust gas components.
• a device for analyzing the exhaust gas from motor vehicles is known from DE 19605 053 A1. With this device, however, as with the measuring devices described in the other publications, problems arise in the required application. Because of the vibrations occurring in a motor vehicle, the measuring system must be built very stably and, moreover, must be insensitive to soot, dust and aerosol deposits. Nevertheless, a high resolution must be achieved, since the concentrations of the components of the exhaust gas to be measured, such as carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxides (NO), are very low, especially in catalytic converter-equipped Otto engine motor vehicles.
• CO carbon monoxide
• HC hydrocarbons
• NO nitrogen oxides
• the infrared gas absorption method is used as the method of exhaust gas analysis.
• the invention proceeds from that The basic idea is that a large optical path length is required to achieve the necessary resolution.
• the cuvette can then be accommodated in a motor vehicle if it is integrated into the construction of the motor vehicle.
• Fig. 2 shows the basic installation of the OBM system in a motor vehicle and the most important components of the combustion system.
• the engine (2) as an internal combustion engine produces exhaust gas
• the catalytic converter (3) converts pollutants into less toxic substances.
• Exhaust gas treatment (5), the analysis device (6), the exhaust system (7) and the data line (8) for connecting the display unit (9) to the analysis device (6) form the OBM system in the motor vehicle.
• the exhaust gas is removed from the exhaust of the motor vehicle behind the catalytic converter, since this is the only way to make a statement about the condition of the entire combustion system and the catalytic converter.
• the exhaust gas treatment is shown as a gas flow diagram in Fig. 3.
• the exhaust gas is cleaned of soot and particles using an exchangeable exhaust gas filter (11).
• a solenoid valve (12) is used to switch between exhaust gas and calibration gas (see chap. 7).
• the measuring gas pump (13) conveys the gas to be measured through the pressure reducer (14) and a flow meter (15) into the analysis device (6).
• the exhaust gas analysis is based on the principle of infrared gas absorption in the analysis device (cuvette).
• This consists of an infrared source (transparent bulb), the radiation of which strikes a measuring head through a measuring section (cuvette).
• the cuvette can consist of a straight, highly reflective tube or of several tubes with mirror heads that reflect the radiation.
• Two pyroelectric sensors are housed in the measuring head, which are equipped with different optical filters and generate a measuring gas dependent and a reference signal. The formation of the quotient of these signals reduces the interference (Te p., Pressure, pollution, aging) on the measurement signal.
• the use of the pyroelectric principle requires a clocked radiation source. An electrical cycle on the radiation source avoids vulnerable mechanical components (choppers).
• the robustness of the measuring system is increased by the fact that the cuvette (measuring section) is made of stainless steel Soiling the device or parts of it fail, it is advantageous that the device is modular and individual components, such as the filter, can be
• a disadvantage of retrofitting OBD is the large number of sensors, for which there is no space and no connections in the electronics. Therefore, the installation of an on-board measuring system is cheaper.
• FIG. 1 Such a modular OBM retrofit system is shown in FIG.
• the exhaust gas is extracted using a sampling probe (16) that is attached to the exhaust end.
• the gas is cleaned in an exhaust gas treatment unit (17), dried and pumped further into the analysis device (6).
• the display unit (9) on the dashboard then displays information about the condition and operation of the OBM system.
• the placement of the retrofit kit in the motor vehicle is shown in Fig.5.
• the sampling probe (16) is attached to the exhaust end.
• the analysis device (6) and the gas preparation (17) can be accommodated in the trunk.
• the display unit (9) can be hung on the ventilation grille or otherwise attached to the dashboard.
• the cold start measuring system Since the cold start measuring system has only a low energy requirement, it can be put into operation before the cold start phase.
• the controller can e.g. by means of a seat bending sensor or a sensor on the ignition lock, through which the HC adsorption trap (10) can also be switched into the exhaust gas path.
• the solenoid valve (12) in the exhaust gas treatment system (5, 17) is automatically switched over after a predetermined time or on the basis of measured external influences, so that outside air gets into the analysis device (6), and the outside air contains the concentrations of CO, HC and NO so low that it can be regarded as zero gas with sufficient accuracy.
• the nuile line is corrected by a mathematical comparison. This means that in addition to the Nuiline, the sensitivities in general also return to their correct value and the system thus displays reproducible values again.
• Fig. 7 shows the effect of this zero line correction. You can see the Nuilin (18) shifted by temperature drift and the correct measurement curve (19) after calibration.
• the method for zero line calibration described in point 7 has the advantage that constant sensitivity adjustment can be dispensed with, since this method also results in the correct corrections for the sensitivity point (and thus all others). Nevertheless, the sensitivity can also be checked using the following procedure:
• the C0 2 content of the atmosphere has an average value of 350 ppm worldwide (in clean air, outside of cities). This fact can be used for
• Exhaust gas analysis device (6) is now supplied with unpolluted outside air, after the above-described zero point adjustment has been carried out, the system must display the mean COr concentration. It can then be assumed with sufficient certainty that the sensitivity point is also correct for the other measuring channels.
• Fig. 8 shows the carbon dioxide concentration in the outside air during a test run. After the zero point was adjusted by synthetic air (20), the journey took place through a small one
• a measurement value is normally determined by forming the quotient from the signal for the pollutant component (measurement signal) and the reference signal.
• the signal curves of the measurement signal and the reference signal are very similar. You can therefore modify the quotient method in such a way that you define a certain tolerance range around the signal curve and set the quotient to "one" within this range. This gives you a range for the zero concentration, and only if this tolerance range is left is one Concentration is displayed according to the values of the real quotient determined. Note: Corresponding the concentration "zero” with the quotient "one" is not absolutely necessary, but generally achieves the best measurement result.
• the real measurement signals that is to say those generated by the exhaust gas, can be distinguished from the more slowly fluctuating, temperature-related fluctuations.
• the first derivative only captures real step functions that arise, for example, when accelerating in a motor vehicle.
• FIG. 9 shows a specific course of the measured values.
• the first derivative (25) was formed from the original measurement signal of the pollutant component HC (24). It can clearly be seen that the measurement signal fluctuations (26) in the derivative (25) caused by temperature influences go to zero.
• Another method of correction is to adjust the signal levels using an electronically adjustable gain control.
• the measurement signal of the reference channel of the infrared detector should always have the original size. However, this signal fluctuates considerably in the motor vehicle due to temperature influences and aging.
• Fig. 1 Contaminant concentration curve in the event of a misfire
• Fig. 2 Basic installation of the OBM system in the motor vehicle
• Fig. 3 Gas plan of the exhaust gas treatment
• Fig. 4 Basic structure of the retrofit kit
• Fig. 5 Housing the retrofit kit in the trunk
• Micro-scale device for continuous measurement of pollutant discharge from motor vehicles

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• Physics & Mathematics (AREA)
• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Combustion & Propulsion (AREA)
• General Physics & Mathematics (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Analytical Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Health & Medical Sciences (AREA)
• Biochemistry (AREA)
• General Health & Medical Sciences (AREA)
• Immunology (AREA)
• Pathology (AREA)
• Investigating Or Analysing Materials By Optical Means (AREA)
• Sampling And Sample Adjustment (AREA)
• Exhaust Gas After Treatment (AREA)
• Combined Controls Of Internal Combustion Engines (AREA)

Applications Claiming Priority (13)

Publications (1)

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• 1998
  • 1998-08-24 AU AU90461/98A patent/AU9046198A/en not_active Abandoned
  • 1998-08-24 CN CN98807663.2A patent/CN1265191A/zh active Pending
  • 1998-08-24 DE DE59800882T patent/DE59800882D1/de not_active Expired - Fee Related
  • 1998-08-24 PT PT98115926T patent/PT909941E/pt unknown
  • 1998-08-24 NZ NZ502545A patent/NZ502545A/en unknown
  • 1998-08-24 JP JP51378899A patent/JP3516691B2/ja not_active Expired - Fee Related
  • 1998-08-24 BR BR9811356-9A patent/BR9811356A/pt not_active IP Right Cessation
  • 1998-08-24 TR TR2000/00507T patent/TR200000507T2/xx unknown
  • 1998-08-24 CA CA002306483A patent/CA2306483A1/fr not_active Abandoned
  • 1998-08-24 EP EP98115926A patent/EP0909941B1/fr not_active Expired - Lifetime
  • 1998-08-24 DK DK98115926T patent/DK0909941T3/da active
  • 1998-08-24 EP EP98952506A patent/EP1007945A2/fr not_active Withdrawn
  • 1998-08-24 ES ES98115926T patent/ES2157629T3/es not_active Expired - Lifetime
  • 1998-08-24 AT AT98115926T patent/ATE202417T1/de not_active IP Right Cessation
  • 1998-08-24 WO PCT/DE1998/002494 patent/WO1999010728A2/fr active IP Right Grant
  • 1998-08-24 RU RU2000104000/28A patent/RU2180107C2/ru not_active IP Right Cessation
• 2001
  • 2001-06-22 GR GR20010400965T patent/GR3036115T3/el not_active IP Right Cessation
  • 2001-09-07 CN CN01132597.6A patent/CN1338625A/zh active Pending

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