Environmental Engineering Reference
In-Depth Information
precise laser analyzers at the edge of the road or on bridges of the highway. The
exhaust gases of jet engines near and at airports and of ship engines near and in
harbors can also be determined by stationary remote sensing equipment.
5.6.1 Vehicle Emissions
Exhaust gas emissions of vehicles are measured at engine test and dynamometer
test benches with certified, large analyzers. Most precise instruments are sensitive
to vibration, so they may be used if they can be positioned without move.
Moreover, they are not suited for hard real traveling conditions during driving.
Due to the high energy demand, the time interval of use in the field is limited.
Micro sensors present a useful way to monitoring real operations. They always
have to be combined with a micro controller system for in situ amplifying, cor-
recting, and linearizing of measured signals.
There are two ways to lower the exhaust gas emissions of vehicles.
• Building new transportation systems with a high technical level of on-board
monitoring; and
• Retrofitting the existing fleet with additional monitoring and regulating devices.
Retrofitting private cars is usually too expensive. However, heavy-duty vehicles
could be advantageously retrofitted with adequate Self Diagnosis.
Vehicle engines have become more intelligent through the introduction of
advanced micro temperature and pressure sensors in the combustion chambers.
They already provide a new control quality of highly dynamically changed
parameters of burning processes. The tendency will lead to the combination and the
integration of sensors, actuators, and micro computer systems for sensing, acting,
and data processing. Future vehicles will become intelligent tools with the highest
possible efficiency for transport, information, communication, and entertainment.
5.6.2 Airplane Emissions
Since 1993, measurements of exhaust gas emissions of a single engine have been
performed at the manufacturer's test facilities as part of the certification process, in
compliance with requirements of ICAO international standards and recommended
practices of Annex 16 to the convention of international civil aviation.
In addition to the test bench, the emissions of the airplane's engine can be
measured on the airplane during idling and taxiing at the airport with help of the
''Driving behind'' method. Disadvantageously, the results depend in a great extend
on weather conditions. Specific aviation measuring technology with the ''Flying
behind'' method provides realistic and very precise results. However, experiments
at high altitudes are dangerous and expensive.
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