NZ502545A - Infrared cell analysis of exhaust emissions with clean air calibration pump - Google Patents
Infrared cell analysis of exhaust emissions with clean air calibration pumpInfo
- Publication number
- NZ502545A NZ502545A NZ502545A NZ50254598A NZ502545A NZ 502545 A NZ502545 A NZ 502545A NZ 502545 A NZ502545 A NZ 502545A NZ 50254598 A NZ50254598 A NZ 50254598A NZ 502545 A NZ502545 A NZ 502545A
- Authority
- NZ
- New Zealand
- Prior art keywords
- measuring
- vehicle
- exhaust
- exhaust gas
- gas
- Prior art date
Links
- 238000004458 analytical method Methods 0.000 title claims abstract description 15
- 239000007789 gas Substances 0.000 claims abstract description 65
- 238000005259 measurement Methods 0.000 claims abstract description 22
- 230000003287 optical effect Effects 0.000 claims abstract description 21
- 239000012080 ambient air Substances 0.000 claims abstract description 13
- 238000010521 absorption reaction Methods 0.000 claims abstract description 12
- 239000000126 substance Substances 0.000 claims abstract description 9
- 230000003321 amplification Effects 0.000 claims abstract description 7
- 238000010276 construction Methods 0.000 claims abstract description 7
- 238000003199 nucleic acid amplification method Methods 0.000 claims abstract description 7
- 238000013461 design Methods 0.000 claims abstract description 6
- 229930195733 hydrocarbon Natural products 0.000 claims description 21
- 150000002430 hydrocarbons Chemical class 0.000 claims description 21
- 238000000034 method Methods 0.000 claims description 19
- 238000012545 processing Methods 0.000 claims description 19
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims description 17
- 229910002091 carbon monoxide Inorganic materials 0.000 claims description 16
- 230000003197 catalytic effect Effects 0.000 claims description 13
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 claims description 12
- 238000012986 modification Methods 0.000 claims description 12
- 230000004048 modification Effects 0.000 claims description 12
- 238000005070 sampling Methods 0.000 claims description 11
- 230000035945 sensitivity Effects 0.000 claims description 11
- 238000012544 monitoring process Methods 0.000 claims description 10
- 238000001179 sorption measurement Methods 0.000 claims description 9
- 230000006870 function Effects 0.000 claims description 8
- 230000005855 radiation Effects 0.000 claims description 8
- 238000002485 combustion reaction Methods 0.000 claims description 6
- 230000001105 regulatory effect Effects 0.000 claims description 6
- 229910001220 stainless steel Inorganic materials 0.000 claims description 6
- 239000010935 stainless steel Substances 0.000 claims description 6
- 239000003638 chemical reducing agent Substances 0.000 claims description 4
- 238000003795 desorption Methods 0.000 claims description 4
- 239000004071 soot Substances 0.000 claims description 4
- 239000000443 aerosol Substances 0.000 claims description 3
- 239000000428 dust Substances 0.000 claims description 3
- 230000000694 effects Effects 0.000 claims description 3
- 238000001556 precipitation Methods 0.000 claims description 3
- 238000012937 correction Methods 0.000 abstract description 12
- 238000009795 derivation Methods 0.000 abstract description 9
- 238000003745 diagnosis Methods 0.000 abstract description 4
- 238000011156 evaluation Methods 0.000 abstract description 4
- 239000003517 fume Substances 0.000 abstract description 2
- 229910000831 Steel Inorganic materials 0.000 abstract 1
- 238000009420 retrofitting Methods 0.000 abstract 1
- 239000010959 steel Substances 0.000 abstract 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 19
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 15
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 8
- 229910052757 nitrogen Inorganic materials 0.000 description 8
- 238000012360 testing method Methods 0.000 description 6
- 239000000356 contaminant Substances 0.000 description 5
- 238000001514 detection method Methods 0.000 description 5
- 239000003570 air Substances 0.000 description 4
- 239000000446 fuel Substances 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 230000008901 benefit Effects 0.000 description 2
- 239000001569 carbon dioxide Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000007689 inspection Methods 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 238000011144 upstream manufacturing Methods 0.000 description 2
- 230000002747 voluntary effect Effects 0.000 description 2
- 230000004075 alteration Effects 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 238000004868 gas analysis Methods 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 231100001231 less toxic Toxicity 0.000 description 1
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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
Abstract
A device for analysing the most important environmentally relevant substances such as CO, HC and NO in exhaust fumes from motor vehicles based the principle of IR gas absorption is disclosed, wherein measuring signals and a reference signal are picked up along an optical measuring distance (special steel tube) using an infrared source and a detector and a measuring value is determined by forming quotients. The On-board Measurement (OBM) system consists of modular components such as a removal device, an exhaust gas processor, an analysis device and an evaluation unit which are integrated into the construction of the motor vehicle. Vibratory conditions in the motor vehicle are compensated by a robust design structure and correction of temperature drift by forming a first derivation and adjustment of the signal height by electronically adjustable amplification regulation. Other correction options are calibration of the zero line with ambient air during switching operations in addition to the creation of a range of tolerance around the noise signals in the detector. The measuring system is to be fitted in the future in all motor vehicles as an addition to the existing OBD (On-board Diagnosis) system. Retrofitting devices can be used for older vehicles.
Description
copy
I
Certified Translation from the German Language
Device for analysing exhaust emissions from motor vehicles 1 Introduction
The exhaust emissions of passenger and commercial vehicles are the cause of various types of harm to the environment. The introduction of emission-limiting legislation has forced, and is forcing, vehicle manufacturers to reduce the emissions of individual vehicles by - for example - developing advanced engines and exhaust systems.
One reason for a vehicle failing to conform to emission regulation is <0 worsening performance, in terms of a gradual increase in exhaust \ emissions, as the vehicle ages. This is caused by wear and also, in part, by the incorrect functioning of components in the drive and
L
V emission-reduction systems.
Ij The normal inspection procedure involves regular tests to attempt to
\ keep emissions at or near their original level. The disadvantage of
S this method is that faults remain undetected until the next inspection,
\ and excessive emissions meanwhile continue to be produced.
In the first few seconds after the engine is started, the catalytic | ^ converter - which has not yet reached its running temperature -
S barely affects the level of harmful exhaust emissions. An engine
produces about 70% of its total emissions just after starting from
^ cold, so an ideal system for reducing harmful emissions would cover this phase, which is precisely the phase that remains untouched by current systems of emission control detection.
2 The state of the art
„On board diagnosis" (OBD) is one new system for reducing harmful emissions. The term refers to an emission control system which uses sensors to monitor the performance of those individual components of a passenger or commercial vehicle that have a bearing on exhaust emissions. An early version of OBD for passenger cars - the OBD I Law - has already been in use for a considerable time in the USA and is gradually being superseded the more stringent OBD II Law for models from 1995 onwards. V^ffe \
OBD I only affected the performance monitoring of component^?
2
i forming part of an electronic engine control system, OBD II requires the control of all components relevant to emissions. The law expressly stipulates the monitoring of catalytic converters, lambda probes, fuel systems, air injection systems, exhaust gas recirculation, tank ventilation and the detection of misfiring. In the event of a component breaking down or malfunctioning, a warning lamp lights up on the dashboard and an error code is memorised. The fault detected should be located as precisely as possible and described. The information is then stored in order to permit swift identification of the fault at the workshop (using a standard interface) and to allow repair of the defective part.
A further step in this field is the use of „On Board Measurement" (OBM). Systems for the direct analysis of vehicle emissions are widely familiar. Some examples, among many others, are the German public patents 32 32 416, 33 39 073, 36 08 122, 37 16 350, 39 32 838, 40 05 803, 41 24 116, 42 35 225, 43 07 190, the DE specification 43 19 282 C1 and US patent specifications 4 803 052 and 5 281 817, along with further patent applications GB 2 264 170 A, EP 0 196 993 A2 and WO 94/09266. These documents should be referred to for explanations in greater detail of items mentioned here.
Applications IM and 121 are concerned, in a narrow sense, with subjects related to this field and are dealt with in greater detail for this reason. Thus patent/1/ describes an infrared measuring system that monitors the operating condition of the catalytic converter via a lateral access opening in the unit and measures the gases present inside. In 121, the system in question is a rapid detector that uses several infrared cells connected in series to permit a chronological resolution of 0.1 - 0.2 sec. Neither source gives an indication of continuous measurement of harmful exhaust system emissions upstream of the catalytic converter.
Written sources reveal that no current measuring system is capable of providing a continuous record of actual emissions, either in the cold-start phase or during operation. Neither is it possible to detect fluctuations or indicate faults.
3 Description of the object of the patent
Vehicles will, in the future, be fitted with an integrated OBM system for the purposes of emission analysis. This system will analyse certain elements of the exhaust gases, and a comparison of current concentrations with a set of stored target values will permit the detection of faults in the ignition system. A warning system will then be activated whenever the ..satisfactory" level specified for the individual model of vehicle is exceeded, clearly and repeatedly, over a period. „Over a period" means an extended length of time, ,.repeatedly" signifies an excessive reading on not one, but various occasions and ..clearly" refers to a concentration that is outside the margin of tolerance specified.
Fig. 1 shows an example of how the concentration of harmful substances is affected by faults in the ignition system (caused by misfiring (1) in this case).
The measurement of emissions is hindered by the fluctuating conditions present in the vehicle. A measuring system must on one hand keep to the general margins of tolerance and specifications valid for the vehicle while, on the other hand, it is precisely the exhaust-related elements of pressure, moisture, temperature and flow rate that are subject to sharp fluctuations. In order to solve this problem, especially robust micro system components are required -both for exhaust gas processing and for the detection of the elements of which the gas consists.
One device for the analysis of vehicle exhaust gases is already familiar in the shape of DE 196 05 053 A1. Problems related to specified operation have however been encountered with this device, as they have with measuring devices described in other documents. The presence of vibrations in the vehicle requires that measuring systems be of highly stable construction and also resistant to soot, dust and aerosol precipitation. They must furthermore attain a high level of resolution, as the constituent components of the exhaust gas being analysed - e.g. carbon monoxide (CO), hydrocarbons (HC), and oxides of nitrogen (NO) -are present in extremely low concentrations, precisely in those petrol-driven vehicles that are fitted with a catalytic converter.
The emission analysis method used in the new OBM system^" lS-1 submitted here is an infrared gas absorption process. This jpfyenttpf*
4
is based the assumption that, in order to obtain the required resolution, optical path length must be increased. The optical cell can thus be fitted to a vehicle if it is incorporated at the construction stage.
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B N
CO
According to one aspect of the invention, there is provided a device for analyzing the most significant environmentally-relevant substances present in the exhaust gas of motor vehicles, such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen monoxide (NO), for the purpose of monitoring the combustion processes in the engine and catalytic converter, and for promptly detecting and rectifying any faults. Such analysis is performed by the infrared gas absorption method, using an optical cell — made of stainless steel and with a relatively long optical path — through which the vehicle exhaust gas is flowed and which is subjected to the light from a special infrared source consisting of a transparent tube. The light from said radiation source is received by a detector, according to the measuring channel/reference channel principle, and a ratio is obtained therefrom to determine the reading. A zero-point adjustment of the measuring device for HC and CO concentrations is performed with clean ambient air, with constant, brief switchover pauses, permitting sensitivity adjustment on the basis of either the natural CO2 concentration in clean ambient air (normal value: 350 ppm) or the CO2 component of the exhaust gas. The device includes means which indicate any increases in pollution emissions that exceed preset limit values, thereby helping to:
- promptly detect any faults that occur in the combustion and exhaust processing systems,
- prevent consequent damage and excessive fuel consumption,
- enable faults to be rectified promptly in the workshop, and
- increase environmentally-aware behaviour on the part of the public by indicating the emission of harmful substances and thus bringing about a voluntary reduction in driving speeds.
According to another aspect of the invention, there is provided a device for analyzing the most significant environmentally-relevant substances present in the exhaust gas of motor vehicles, such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen monoxide (NO), for the purpose of monitoring the combustion processes in the engine and catalytic converter, and for promptly detecting and rectifying any faults. Such analysis is performed by the infrared gas absorption method, using an optical cell — made of stainless steel and with a relatively long optical path — through which the vehicle exhaust gas is flowed and which is subjected to the light from a ^ special infrared source consisting of a transparent tube. The light from said radiation 2* source is received by a detector, according to the measuring channel/reference channel principle, and a ratio is obtained therefrom to determine the reading. A temperature drift is corrected by producing the first derivative of the concentration curve, in which derivative the step functions of the motor vehicle drive system can be differentiated cji
01
4A tl from the slow drift. The device includes means which indicate any increases in ^ pollution emissions that exceed the pre-set limit values, thereby helping to:
- promptly detect any faults that occur in the combustion and exhaust ' ft processing systems, JP?®
- prevent consequent damage and excessive fuel consumption, ^
- enable faults to be rectified promptly in the workshop, and
- increase environmentally-aware behaviour on the part of the public by indicating the emission of harmful substances and thus bringing ab'out a voluntary reduction in driving speeds.
The device may be accommodated on the underbody of the vehicle, in the boot, in the vehicle body, or anywhere else suitable on the vehicle.
The device is suitable for use in an on board measuring system (OBM), preferably wherein the measuring system is integrated into the vehicle's design. The measuring system preferably comprises modular components including, for example, a sampling point, exhaust-gas processing unit, analysing device, data line, and display unit. The individual components can be replaced, due to their modular design, and can also be retrofitted into the vehicle. The exhaust processing unit is so robust and stable — comprising components optionally including an exchangeable filter (regenerable by heat), a solenoid valve, a gas metering pump, a pressure reducer, and a flow meter —
that the parts are immune to deposits of soot, dust, and aerosol precipitation caused by the strongly-fluctuating, tough conditions prevailing in the vehicle.
Preferably, the device in accordance with the invention comprises an infrared detector reference channel measuring signal which signal level is readjusted by means of an electronically regulated amplification controller using the undisturbed reference signal curve as a base constant.
Preferably, the device in accordance with the invention is suitable for use in a modification kit that does not require official approval for older vehicles, and consists of a sampling sensor attached to the end of the exhaust pipe, an analyzing device with exhaust-gas processing unit in the boot, and a display unit on the dashboard. The modification kit contains officially authorised performance-characteristics data — according to the model and year of construction of each vehicle — as a reference base for the on-board measurements, so that, with the exception certain vintage vehicles, no direct measurements need to be made to establish the specific performance-characteristics.
IPONZ
-3 JUN 2003
4B
Preferably, the device in accordance with the invention is activated by means of a sensor (e.g. seat occupation sensor, ignition lock sensor, other switching elements) so that the device can begin measuring from the moment of cold-starting and can control the adsorption trap flexibly according to the current operating conditions, so that adsorption and desorption can occur at the optimum moment.
4 Technical design of the measuring system
The main assembly of the OBM system in a vehicle is shown in Fig. 2, along with the main components of the ignition system. The engine (2) produces exhaust fumes as it burns fuel. In the catalytic converter (3), harmful elements are transformed into less toxic substances. The vehicle OBM system consists of the sampling point (4), exhaust gas processing unit (5), analysing device (6), exhaust . system (7) and data cable (8) that provides the link between the display unit (9) and analysing device (6).
Gas is extracted from the exhaust system upstream of the catalytic converter, as this is the only way in which an evaluation of the condition of the ignition system as a whole can be made.
Exhaust gas processing is illustrated in the gas flow diagram (Fig. 3). Soot and particles are removed from the exhaust gas using a. disposable filter (11). A solenoid valve (12) is used to change over between exhaust gas and calibration gas (see chapter 7). The measuring gas pump (13) sends the gas to be measured to the analysing device (6) via the pressure reducer (14) and flow meter (15).
Exhaust gas analysis is carried out in the analysis device (optical cell) following the principle of infrared gas absorption. This device consists of an infrared source (transparent tube), the radiation from which is directed to the measuring head via a measured length (optical cell). The optical cell can consist of one straight, highly reflective tube or of several tubes with reflective heads. The two pyroelectric measuring sensors fitted to the measuring head are equipped with various optical filters and produce one signal that depends on measurements and another which acts as a reference signal. The ratio formation of these signals reduces the disturbing influences (temperature, pressure, contamination) acting on the measuring signal. The use of the pyroelectric principle requires a ... synchronised radiation source. Electrical timing of the radiation;,-,^-*6' source avoids delicate mechanical components (chopper). Tt?e measuring system is thus rendered more robust, with an optical ^elJ.«
(measured length) made of stainless steel. In the event of the device being contaminated or suffering component faults, the advantage of the modular construction of the unit becomes clear. Single components such as filters can simply be replaced.
Modification kit for emission analysis on older vehicles
In the case of older vehicles, which have not been fitted by the manufacturer with an OBD or OBM system, engine and exhaust gas processing performance cannot be measured other than by analysis of the exhaust gas itself. For this reason, a modification option should be available.
The disadvantage of carrying out modifications with an OBD system is the large number of transducers, for which there is neither sufficient room nor electronic connections. It is therefore more convenient to install an on board measuring system.
Fig. 4 shows a modular OBM modification system of this type. Exhaust gas sampling is carried out using a sampling sensor (16) fitted to the end of the exhaust pipe. The gas is cleaned and dried in the exhaust gas processing unit (17) and then pumped onwards to the analysing device (6). The display unit (9) on the dashboard then indicates information about the status and operation of the OBM system.
The fitting of the modification kit to the vehicle is illustrated in Fig. 5. This involves attaching the sampling sensor (16) to the end of the exhaust pipe, while the analysing device (6) and gas processing unit (17) can be installed in the car boot. The display unit (9) can be hung from a ventilator grille or fitted elsewhere on the dashboard.
6 Cold-start measurement and adsorption trap
The cold-start phase (see Fig. 6) is when 70% of total engine emissions are produced, and an on board measurement system calibrates these gases. These readings can be used to activate an HC adsorption trap (10, see Fig. 2) used for collecting cold-start emissions in the exhaust flow path. Emission measuring makes it possible to synchronise the adsorption trap in the exhaust flow path to activate at exactly the right moment, or to start desorption. Desorption of the small amount of retained hydrocarbons untphe
catalytic converter reaches a temperature at which satisfactory conversion is guaranteed.
The energy consumption of the cold-start measuring system is extremely low, so it can enter operation before the cold-start phase has actually commenced. Control can be carried out, for example, by means of either a seat occupation sensor or a sensor on the ignition lock, which can also be used to activate the HC adsorption trap in the exhaust flow path.
7 Reference line calibration
The measuring principle of infrared gas absorption is sufficiently well known. The problems with this measuring principle with regard to fluctuating ambient conditions have already been described in section 3. We will now examine the various measurement correction methods used.
The most common problem is the shifting of the zero point - i.e. the reading for uncontaminated gas is not zero. This problem can be solved by calibrating the system with ambient air, proceeding as follows:
The solenoid valve (12) in the exhaust gas processing unit (5,17) is automatically switched over either after a pre-set period or as a result of detected external factors, allowing ambient air to enter the analysis device (6). The concentrations of CO, HC and NO present in the ambient air are so low that they can safely be regarded as zero. The use of mathematical compensation allows the zero line to be calibrated. After this has been carried out, the sensitivity of the device usually recovers its original levels and the system begins once again to display reproducible readings. Fig. 7 shows the effect of a zero line correction. The graph illustrates how the zero line (18) has been displaced by temperature drift and also shows the re-corrected measuring curve (19) produced after calibration. This procedure, with an interruption in emission recording, has no influence in terms of nominal values on the meaningfulness of measurements, whose purpose is - in any case - the detection of faults in the exhaust system rather than the providing of continuous monitoring.
7
8 Adjusting the sensitivity of the measuring signals using the C02 concentration of the ambient air
The zero-calibration procedure described in section 7 has the advantage of avoiding the need for constant sensitivity adjustment,
as this procedure also produces the right correction for the sensitivity level (and thus all others). A sensitivity check can nevertheless be carried out as follows:
The atmosphere in all parts of the world (with clean non-city air) has an average C02 concentration of 350ppm. This fact can be used to check sensitivity, as this concentration matches the measuring ranges of the components normally detected in the stream of exhaust gas. CO, HC and - above all - NO in fact have weaker absorption bands than C02, but with correspondingly higher peak concentrations. According to the Lambert-Beerschen equation, the same optical cell length or - in practical terms - the same optical cell, can thus be used. If uncontaminated ambient air is now fed into the exhaust gas analysing device (6), the system should show the average C02 concentration - once the zero point reset procedure described above has been carried out. One can now be sufficiently sure that the sensitivity level of the other measurement factors is also correct.
The disadvantage of the above procedure is that local C02 concentrations fluctuate sharply due to external influences. This is especially true in densely populated areas, where road traffic can produce extremely high concentrations of C02. Fig 8 shows the carbon dioxide concentration of the ambient air during a test drive. After adjustment of the zero point using synthetic air (20), the vehicle was driven through a small municipality (21) where the C02 concentration was relatively constant. A test drive through a larger town (22)
with crossings and traffic lights reveals high, sharply-fluctuating C02 concentrations. Finally, a measurement carried out in a quiet interior courtyard (23) is closer to a natural C02 concentration.
9 Sensitivity adjustment via the C02 concentration in the exhaust gas
One possible way of avoiding the problems resulting from the fluctuations from natural C02 concentrations described in section 8.. , • 0 4 is the monitoring of the C02 concentration in the vehicle exhau.st: The ignition process makes this value relatively stable, so that thi^
it
8
concentration can be used as a reference value for adjusting the sensitivity of the individual meter flumes. However, the high concentration (12% by volume) of C02 in the exhaust gas means that the C02 beam path in the optical measuring cell must be arranged differently to that used for other harmful gases. The optical path for C02 measurement basically has to be shorter than that used for the contaminants CO, NO and HC.
Correction - using a software-controlled filter - of zero line of measuring signal displaced due to temperature fluctuations
A measurement value is normally determined by the production of a ratio from the signal for the contaminant present (measuring signal) and the reference signal.
The signal progressions for measuring signals and reference signals reveal a great similarity. A ratio procedure can thus be modified if a certain margin of tolerance is determined around the signal progression and the ratio is set to „one" within this margin. This allows a range for zero concentration to be obtained, and only in the event of this margin of tolerance being exceeded will a concentration corresponding to the values of the then determined real ratio be displayed. Note: the concentration „zero" need not necessarily correspond to the ratio „one", but it does obtain the best measuring result.
11 Compensation of temperature drift by examination of the dynamics of the signal progressions
Experience shows that extreme dynamic conditions are present in motor vehicles (brusque momentary system alterations, compared to the cycle period of the radiation emitter). This means that it is easy to differentiate between genuine measuring signals (i.e. those produced by the exhaust gas) and the slower-fluctuating variations that depend on temperature. To carry out correction, the first derivation of the concentration process must be produced according to time. The first derivation records only genuine step functions that occur, for example, when the vehicle accelerates. Fig. 9 shows an actual measuring value progression. The first derivation (25) was produced from the original measuring signal of contaminant HC (24). It can be clearly seen that measurement signal fluctuations (26) provoked by the influence of temperature approach zero in the derivation (25).
9
Once the step function places from the first derivation have been found according to time, the points can be recognised with clear step characteristics. If such a genuine step function appears, i.e. if a measurement value exceeds the previously defined margin of tolerance by a permitted amount relative to the differential curve, this point must be used as a reference relative to the actual concentration curve used for evaluation. When the first derivation returns to zero, the software-controlled filter once again emits the zero line as an unaltered, stable line. Thus you have at your disposal during the test drive one of two things. The first possibility is an absolute zero line - without fluctuations, as no step functions have appeared and the fluctuations caused by temperature are ignored. The other possibility is that whenever real, dynamic step functions occur, such as when accelerating, changing gear, braking, etc., the original measuring signals (obtained from the concentration curve) are observed according to the first derivative.
12 Setting the original signal strengths in the channels of the IR gas analyser
A further correction method involves resetting the signal strength by means of an electronically regulated amplification controller.
Since the margin of reference for infrared gas absorption is set in such a way that virtually no absorption takes place at this limit, the infrared detector reference channel measuring signal should always maintain its original strength. The effects of temperature and vehicle wear do however cause noticeable fluctuations in this signal.
In order to compensate for the signal fluctuations caused by temperature conditions, the possibility exists to monitor continuously the reference signal by means of a measurement, control and regulating device built into the system. Whenever the reference signal deviates by a pre-defined margin from the value originally adjusted at initial calibration, all signals are realigned - using an electronically regulated amplification controller - with the original signal strength. Fig. 10 shows the original curve for the reference signal (27), the weakened curve resulting from wear or temperature drift (28) and the curve that has been corrected by electronically controlled amplification (29). This method retains the full range of signal dynamics.
Summary
This description refers to a device for analysing the most important environmentally relevant substances, such as CO, HC and NO, that are present in vehicle exhaust emissions. It is based on the principle of IR gas absorption. This involves producing measuring signals and a reference signal in a measured optical length (stainless steel tube), with the aid of an infrared source and detector. The production of a ratio then gives a reading and a warning signal is produced whenever a certain limit value is exceeded.
The OBM system is made up of modular components, such as a sampling device, exhaust gas processing unit, analysing device and evaluation unit, which are built into the vehicle (see Fig. 2).
The fluctuating conditions present in the vehicle are compensated for by robust construction and correction of temperature drift by means of production of the first derivation and readjustment of signal strength using an electronically regulated amplification control. Further correction possibilities are: calibration of the zero line using ambient air via a switchover system, and the establishment of a tolerance limit around the noise signals in the detector.
The measuring system should in future be installed in all motor vehicles as an extension to existing OBD (on board diagnosis) systems. Modification kits are available for older vehicles.
■Vs.-l.Jj
13
Key to illustrations
Fig. 1: Contaminant concentrations caused by misfiring
1 Misfiring
Fig. 2: Main installation of the OBM system inside the motor vehicle
2 Engine
3 Catalytic converter
4 Sampling point
Exhaust processing unit
6 Analysing device
7 Exhaust system
8 Data link
9 Display unit
HC adsorption trap
Fig. 3: Exhaust processing unit gas flow diagram
11 Exhaust gas filter
12 Solenoid valve
13 Measuring gas pump
14 Pressure reducer
Flow meter
Fig. 4: Main layout of modification kit
16 Sampling sensor
17 Exhaust gas processing unit
Fig. 5: Fitting the modification kit in the car boot
Fig. 6: Cold-start measurement
14
Fig. 7: Zero-line correction
18 Zero line displaced by temperature drift
19 Corrected measuring curve
Fig. 8: Carbon dioxide concentration in ambient air
Adjustment using synthetic air
21 Test drive through a small municipality
22 Test drive through a larger town
23 Measurement carried out in quiet interior courtyard
Fig. 9: Derivation in correction function
24 Original measuring signal
First derivative
26 Measuring signal fluctuation due to temperature Fig. 10: Correcting signal strength
27 Original progression of reference signal
28 Curve affected by wear
29 Corrected signal curve
Bibliography hi United States Patent: System for monitoring gas composition. Patent number 5,475,223. Date of Patent: Dec. 12 1995
121 Public patent DE 196 05 053 A1: On board diagnosis (OBD) procedure and device on micro-scale for the constant monitoring of motor vehicle contaminant emissions
11
502545
Claims (10)
1. A device for analyzing the most significant environmentally-relevant substances present in the exhaust gas of motor vehicles, such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen monoxide (NO), for the purpose of monitoring the combustion processes in the engine and catalytic converter, and for promptly detecting and rectifying any faults: such analysis being performed by the infrared gas absorption method, using an optical cell — made of stainless steel and with a relatively long optical path — through which the vehicle exhaust gas is flowed and which is subjected to the light from a special infrared source consisting of a transparent tube; said light from said radiation source being received by a detector, according to the measuring channel/reference channel principle; and a ratio being obtained therefrom to determine the reading; and wherein a zero-point adjustment of the measuring device for HC and CO concentrations is performed with clean ambient air, with constant, brief switchover pauses, permitting sensitivity adjustment on the basis of either the natural CO2 concentration in clean ambient air (normal value: 350 ppm) or the CO2 component of the exhaust gas, said device including means which indicate any increases in pollution emissions that exceed pre-set limit values.
2. A device for analyzing the most significant environmentally-relevant substances present in the exhaust gas of motor vehicles, such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen monoxide (NO), for the purpose of monitoring the combustion processes in the engine and catalytic converter, and for promptly detecting and rectifying any faults: such analysis being performed by the infrared gas absorption method, using an optical cell — made of stainless steel and with a relatively long optical path — through which the vehicle exhaust gas is flowed and which is subjected to the light from a special infrared source consisting of a transparent tube; said light from said radiation source being received by a detector, according to the measuring channel/reference channel principle; and a ratio being obtained therefrom to determine the reading; and wherein IPONZ " 3 JUN 2003 12 CJ1 o N> a temperature drift is corrected by producing the first derivative of the ^ concentration curve, in which derivative the step functions of the motor vehicle drive system can be differentiated from the slow drift effects, said device including means which indicate any increases in pollution emissions that exceed pre-set limit values.
3. A device in accordance with claim 1 or 2, in which the device is accommodated on the underbody of the vehicle, in the boot, in the vehicle body, or anywhere else suitable on the vehicle.
4. A device in accordance with claims 1-3, for use in an on board measuring system in which the measuring system is integrated into the vehicle's design; wherein said measuring system comprises modular components including a sampling point, exhaust-gas processing unit, analysing device, data line, and display unit; and the individual components can be replaced, due to their modular design, and can also be retrofitted into the vehicle; and wherein the exhaust processing unit comprises components optionally including an exchangeable filter (regenerable by heat), a solenoid valve, a gas metering pump, a pressure reducer, and a flow meter that are immune to deposits of soot, dust, and aerosol precipitation.
5. A device in accordance with any of claims 1-4, in which an infrared detector reference channel measuring signal level is readjusted by means of an electronically regulated amplification controller using the undisturbed reference signal curve as a base constant.
6. A device in accordance with any of claims 1-5, for use in a modification kit for older vehicles consisting of a sampling sensor attached to the end of the exhaust pipe, an analyzing device with exhaust-gas processing unit in the boot, and a display unit on the dashboard; said modification kit containing officially authorised performance-characteristics data according to the model and year of construction of each vehicle as a reference base for the on-board measurements, so that, with the exception certain vintage vehicles, no direct measurements need to be made to establish the specific performance-characteristics. IPONZ - 3 JUN 2003
7. A device in accordance with any of claims 1-6, in which the device is activated by means of a sensor so that the device can begin measuring from the moment of cold-starting and can control the adsorption trap flexibly according to the current operating conditions, so that adsorption and desorption can occur at the optimum moment.
8. A device in accordance with claim 7 in which the sensor is a seat occupation sensor or an ignition lock sensor.
9. A device according to claim 1 substantially as herein described or exemplified.
10. A device according to claim 2 substantially as herein described or exemplified. IPO NZ ■3 J UN 2003
Applications Claiming Priority (7)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19736864 | 1997-08-25 | ||
| DE19739869 | 1997-09-11 | ||
| DE19743954A DE19743954C2 (en) | 1997-10-04 | 1997-10-04 | Cold start measuring system for measuring the cold start emission |
| DE19821136A DE19821136C2 (en) | 1997-08-25 | 1998-05-12 | Device for analyzing the exhaust gas from motor vehicles |
| DE19831457A DE19831457C2 (en) | 1997-09-11 | 1998-07-14 | Retrofit method for recording the exhaust gas composition in the motor vehicle for self-installation |
| DE19835537 | 1998-08-06 | ||
| PCT/DE1998/002494 WO1999010728A2 (en) | 1997-08-25 | 1998-08-24 | Device for analysing exhaust emissions from motor vehicles |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| NZ502545A true NZ502545A (en) | 2003-09-26 |
Family
ID=27545080
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| NZ502545A NZ502545A (en) | 1997-08-25 | 1998-08-24 | Infrared cell analysis of exhaust emissions with clean air calibration pump |
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| EP (2) | EP0909941B1 (en) |
| JP (1) | JP3516691B2 (en) |
| CN (2) | CN1265191A (en) |
| AT (1) | ATE202417T1 (en) |
| AU (1) | AU9046198A (en) |
| BR (1) | BR9811356A (en) |
| CA (1) | CA2306483A1 (en) |
| DE (1) | DE59800882D1 (en) |
| DK (1) | DK0909941T3 (en) |
| ES (1) | ES2157629T3 (en) |
| GR (1) | GR3036115T3 (en) |
| NZ (1) | NZ502545A (en) |
| PT (1) | PT909941E (en) |
| RU (1) | RU2180107C2 (en) |
| TR (1) | TR200000507T2 (en) |
| WO (1) | WO1999010728A2 (en) |
Families Citing this family (23)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20020006135A (en) * | 2000-07-11 | 2002-01-19 | 이구택 | Pyrometer, Signal Processing Unit |
| JP3899004B2 (en) * | 2002-09-27 | 2007-03-28 | 株式会社堀場製作所 | In-vehicle HC measuring device |
| GB0416372D0 (en) * | 2004-07-22 | 2004-08-25 | Evanesco Ltd | Methods and apparatus for target sensing using profiles |
| JP4594277B2 (en) * | 2006-05-31 | 2010-12-08 | トヨタ自動車株式会社 | Sensor unit in exhaust gas analyzer |
| DE102009054817A1 (en) * | 2009-12-17 | 2011-06-22 | Ford Global Technologies, LLC, Mich. | Method for on-board error diagnosis in operation of internal combustion engine of motor vehicle, involves determining actual emission value in actual operating condition, and generating error signal based on index value |
| JP2014514535A (en) * | 2011-03-16 | 2014-06-19 | グローバル エムアールヴィ、インコーポレイテッド | Emission measurement device |
| US8461531B2 (en) * | 2011-10-11 | 2013-06-11 | The Boeing Company | Detecting volcanic ash in jet engine exhaust |
| RU2494366C2 (en) * | 2011-11-17 | 2013-09-27 | Открытое акционерное общество "Московское машиностроительное предприятие им. В.В. Чернышёва" | Complex for air sampling |
| CN102607659B (en) * | 2012-02-03 | 2015-01-07 | 吴明 | Method for fuel detection and conversion in vehicle standard state |
| CN102608064B (en) * | 2012-04-10 | 2014-09-10 | 河南汉威电子股份有限公司 | Three-channel infrared gas sensor for CO gas high-precision detection |
| CN103424261B (en) * | 2012-05-23 | 2017-05-24 | 株式会社堀场制作所 | Exhaust gas analyzing apparatus, exhaust gas analyzing system and method of operating the same |
| US9410466B2 (en) * | 2012-12-05 | 2016-08-09 | Ford Global Technologies, Llc | Exhaust humidity sensor |
| CN103063805B (en) * | 2012-12-17 | 2015-08-26 | 浙江达峰汽车技术有限公司 | A kind of exhaust analyzer gas passage automatic switchover system |
| RU2519405C1 (en) * | 2013-02-25 | 2014-06-10 | Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Оренбургский государственный университет" | Device for automotive engine off-gas sampling |
| US9970372B2 (en) * | 2014-02-14 | 2018-05-15 | Ford Global Technologies, Llc | Method of diagnosing an exhaust gas sensor |
| US9664594B2 (en) * | 2015-02-19 | 2017-05-30 | Ford Global Technologies, Llc | Ambient humidity detection transmission shifts |
| US9435244B1 (en) * | 2015-04-14 | 2016-09-06 | General Electric Company | System and method for injection control of urea in selective catalyst reduction |
| GB201519926D0 (en) * | 2015-11-11 | 2015-12-23 | Horiba Mira Ltd | Emmissions testing system |
| CN106353105B (en) * | 2016-08-12 | 2018-09-14 | 汪林 | Car consumption credit method and Car Comprehensive Performance Evaluation method |
| JP6716443B2 (en) | 2016-12-14 | 2020-07-01 | 株式会社堀場製作所 | In-vehicle exhaust gas analysis system, in-vehicle exhaust gas analysis system inspection system, and in-vehicle exhaust gas analysis system inspection method |
| US10013821B1 (en) * | 2017-03-14 | 2018-07-03 | Ford Global Technologies, Llc | Exhaust gas analysis |
| EP4133171A1 (en) | 2020-04-06 | 2023-02-15 | Toyota Motor Europe | System and method for predicting high frequency emission information of an engine |
| CN113311114B (en) * | 2021-05-27 | 2023-04-14 | 河南省计量科学研究院 | Mobile calibration detection system of tail gas remote measuring device |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5060505A (en) * | 1989-09-12 | 1991-10-29 | Sensors, Inc. | Non-dispersive infrared gas analyzer system |
| DE4121520C2 (en) * | 1990-07-07 | 2003-02-13 | Volkswagen Ag | Circuit arrangement for preheating ignition devices in the manner of glow plugs for an internal combustion engine driving a motor vehicle |
| US5709082A (en) * | 1994-06-27 | 1998-01-20 | General Motors Corporation | Modulation schemes for on-board diagnostic exhaust system |
| DE29504088U1 (en) * | 1995-03-10 | 1996-07-11 | Palocz Andresen Michael Dr Ing | On-board diagnostic / OBD / device on a micro scale for the continuous measurement of pollutant discharge from motor vehicles |
| FI102570B (en) * | 1995-12-29 | 1998-12-31 | Instrumentarium Oy | Method and apparatus for determining the alcohol content of a gas mixture |
-
1998
- 1998-08-24 TR TR2000/00507T patent/TR200000507T2/en unknown
- 1998-08-24 NZ NZ502545A patent/NZ502545A/en unknown
- 1998-08-24 AU AU90461/98A patent/AU9046198A/en not_active Abandoned
- 1998-08-24 EP EP98115926A patent/EP0909941B1/en not_active Expired - Lifetime
- 1998-08-24 BR BR9811356-9A patent/BR9811356A/en not_active IP Right Cessation
- 1998-08-24 CA CA002306483A patent/CA2306483A1/en not_active Abandoned
- 1998-08-24 DK DK98115926T patent/DK0909941T3/en active
- 1998-08-24 AT AT98115926T patent/ATE202417T1/en not_active IP Right Cessation
- 1998-08-24 DE DE59800882T patent/DE59800882D1/en not_active Expired - Fee Related
- 1998-08-24 WO PCT/DE1998/002494 patent/WO1999010728A2/en active IP Right Grant
- 1998-08-24 CN CN98807663.2A patent/CN1265191A/en active Pending
- 1998-08-24 JP JP51378899A patent/JP3516691B2/en not_active Expired - Fee Related
- 1998-08-24 PT PT98115926T patent/PT909941E/en unknown
- 1998-08-24 RU RU2000104000/28A patent/RU2180107C2/en not_active IP Right Cessation
- 1998-08-24 ES ES98115926T patent/ES2157629T3/en not_active Expired - Lifetime
- 1998-08-24 EP EP98952506A patent/EP1007945A2/en not_active Withdrawn
-
2001
- 2001-06-22 GR GR20010400965T patent/GR3036115T3/en not_active IP Right Cessation
- 2001-09-07 CN CN01132597.6A patent/CN1338625A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| JP3516691B2 (en) | 2004-04-05 |
| EP0909941B1 (en) | 2001-06-20 |
| CA2306483A1 (en) | 1999-03-04 |
| ES2157629T3 (en) | 2001-08-16 |
| EP1007945A2 (en) | 2000-06-14 |
| BR9811356A (en) | 2000-09-12 |
| ATE202417T1 (en) | 2001-07-15 |
| DK0909941T3 (en) | 2001-09-03 |
| TR200000507T2 (en) | 2000-07-21 |
| DE59800882D1 (en) | 2001-07-26 |
| WO1999010728A2 (en) | 1999-03-04 |
| CN1265191A (en) | 2000-08-30 |
| PT909941E (en) | 2001-12-28 |
| RU2180107C2 (en) | 2002-02-27 |
| AU9046198A (en) | 1999-03-16 |
| JP2001523317A (en) | 2001-11-20 |
| CN1338625A (en) | 2002-03-06 |
| GR3036115T3 (en) | 2001-09-28 |
| WO1999010728A3 (en) | 1999-05-06 |
| EP0909941A1 (en) | 1999-04-21 |
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