Engine exhaust measurements

Engine Exhaust Measurements. Automobile exhaust, sampled from the dilution tube, was studied using the spectrophone and the 514.5nm line of an Ar ion laser. 

Eckbreth A C, Dobbs G M, Stufflebeam J H and Tellex P A 1984 CARS temperature and species measurements in augmented jet engine exhausts App/. Opt. 23 1328-39... 

Laser Doppler Velocimeters. Laser Doppler flow meters have been developed to measure Hquid or gas velocities in both open and closed conduits. Velocity is measured by detecting the frequency shift in the light scattered by natural or added contaminant particles in the flow. Operation is conceptually analogous to the Doppler ultrasonic meters. Laser Doppler meters can be appHed to very low flows and have the advantage of sensing at a distance, without mechanical contact or interaction. The technique has greatest appHcation in open-flow studies such as the deterrnination of engine exhaust velocities and ship wake characteristics. 

Davis, D. D.,Jr, G. L. Stevens,Jr., D. Moore, and G. M. Stokes, Theoretical and Measured Attenuation of Mufflers at Room Temperature without How, with Comments on Engine— Exhaust MufQer Design, Technical Note 2893, Langley Aeronautical Laboratory, National Advisory Committee For Aeronautics, Washington, D.C., Feb. (1953). 

One of the studies at the Fraunhofer Institute clearly indicated that the toxicity resulting from chronic inhalation of diesel engine exhaust was due to the particulate component of the exhaust and not the gases (21). Rats were exposed by inhalation over most of their life span to filtered or unfiltered diesel exhaust. Exposures were 19 h/day, 5 days/wk with soot concentrations of 4 mg/m3. All of the measures of toxicity determined, including decreases in body weight, alveolar clearance, and various measures of lung function, as well as the induction of lung tumors, were observed only In animals exposed to the unfiltered exhaust. 

In a study conducted at the Lovelace Inhalation Toxicology Research Institute (ITR1), rats were exposed for up to 30 months, 7 h/day, 5 days/wk, to diesel exhaust containing 0, 0.35, 3.5, or 7.1 mg soot/m3 of air. The diesel engine exhaust was generated as indicated in the section of this paperon "Physical/Chemical Characteristics of Diesel Soot." The lowest exposure concentration, 0.35 mg soot/m3, is directly relevant to some occupational exposures and is 10 to 100 times higher than any current or anticipated environmental exposures. Observations of the animals were made at 6-mo intervals and included measures of dosimetry (mg soot/g lung),... 

The difference between the catalyst responses in the two feed-streams may be related to factors which are yet unknown in addition to SO- poisoning of the water-gas shift reaction. Instruments which have 10%-to-90% response times of less than 0.1 s are required to measure the dynamic response of a catalyst in engine exhaust. 

Figure 7. Schematic diagram of the apparatus used to study the dynamic behavior of three-way catalysts in engine exhaust (14, 15j. This apparatus was used to make the measurements shown in Figures 8 and 9.

N-nitrosation by oxides of nitrogen at neutral and alkaline pH has an important bearing on assessing human exposure to N-nitroso compounds, particularly as this route has been almost totally disregarded in the past. Those analytical techniques which have relied on a basic pH to inhibit nitrosation need further study to ensure the validity of the findings. For the same reason, measurements of N-nitrosamines in engine exhausts and tobacco smoke are likely to be particularly artifact prone. 

In a later phase of work, the formic acid concentration in mine air subject to diesel emissions was measured. The expected concentrations were about one hundred times lower than those found in engine exhaust. The efficiency of the collection scheme was again measured under these conditions of challenge concentration (0.06 mg/m3). The collection efficiency was found to be 92.2% at this level (Table IV). 

Aircr t Gas Turbine Engine Exhaust Smoke Measurement, Aerospace... 

The kinetic experiments effected at the engine exhaust on MFI catalysts at different Cu and A1 content, and the relevant characterisation measurements, evidenced the following ... 

The filters were glued onto a quartz tube with an outer diameter of 20 mm and a wall thickness of 1.5 mm using Ceramabond 569. The quartz tube was then placed in the oven, as illustrated in Figure 1. A side stream of the engine exhaust gas, generally 12 1/min, was pumped through the filter. The oven temperature was controlled. The temperature within the filter was normally about 20 K below the oven temperature. Before each experiment, the pressure drop over the clean, unused trap was measured with air at a filter temperature of 575 K. 

Oxygen sensors in automotive applications are used to measure the air fuel (A/F) ratio of engine exhaust gases and to control the optimum A/F ratio for perfect exhaust gas after-treatment by catalytic converters [1]. Therefore, they are also known as lambda or A/F ratio sensors. 

As explained below, it is suggested that accurate measurements of acoustic noise very near the jet plume may provide critical data which are required to validate computational jet-noise models. Further, it appears that only data acquired very near the plume can provide such information. Although there are several different specific sources of jet-engine noise [1], they are all linked to unsteady flows associated with the mean flow of the engine exhaust. 

The applications of isokinetic sampling cover but are not limited to the sampling of aerosols such as flu gas in chimney, soots (unbumed carbons) from diesel engine exhaust, dusts suspended in the atmosphere, and fumes from various sprayers measurements of particulate mass fluxes in pneumatic transport pipelines and other particulate pipe flows solid fuel (also some liquid fuels) distributions in furnaces, engines, and other types of combustors and calibrations of instruments for the measurements of particle mass concentrations. Isokinetic sampling can also be applied to flows with liquid droplets. In this case, the droplet sample is usually collected by an immiscible liquid (Koo et al., 1992 Zhang and Ishii, 1995). 

Solid state sources are not able presently to achieve the required power output over such a wide band 10% of the centre frequency would represent a typically good -3 dB power bandwidth. For single component measurements it is not necessary to scan the entire waveguide band, the 6-8 GHz FWHM of typical lines at 50-200 GHz, could be adequately covered by a Gunn device. This would be an attractive method for dedicated measurements at atmospheric pressure of flame combustion products in smoke stack and engine exhaust effluents, e.g. oxygen and carbon monoxide whose concentrations at >1 ppm are particularly important. 

As with some of the chronic animal studies, exposures in most of the occupational miner cohorts consist of exposure to radon and radon progeny in the presence of other contaminants such as uranium ore dust, diesel-engine exhaust, or other mine pollutants. Only a few studies of lung cancer associated with environmental exposures to radon and radon daughters have been reported. These studies are primarily case-control or case-referent studies that involve a small number of subjects and have exposure estimates that are based on either surrogates for measurements or limited measurements. Additional studies of the extent of the hazard associated with environmental radon daughter exposures would provide useful information since radon is an ubiquitous substance, especially as they compare to estimates of the human health hazard based on the occupational setting. 

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