Environmental Engineering Reference
In-Depth Information
2 500
2 000
high emission level
1 500
1 000
low emission level
5 00
0
0
20
40
60
80
100
time [s]
Fig. 1.7
Unburned raw hydrocarbon concentration in a mid-size car without and with errors
Spark ignition engine emits larger amounts of unburned hydrocarbons and
carbon monoxide upstream to the catalyst which can be precisely recorded in the
automatic cold starting phase (see Fig. 1.7 ).
Peaks in cars have short time intervals between 0.1 and 1.0 s.
Exhaust gas emissions of airplanes' and ships' engines are significantly dif-
ferent from car engine emissions. However, despite all of the differences in
emission characteristics, the basic functions are the same. The composition of
combustion products generally depends on the type and the load of the engine, and
the operating conditions.
On airplanes, micro sensors for burning products could be installed in the
combustion chamber, similar to the temperature and pressure sensors. Micro
measuring systems could compare the signals of individual jet engines measured
against each other. On the basis of these variable and multistage comparisons, even
small changes within the engines can be discovered over time and compensated
with fitted correction measures. Micro emission measuring systems can combine
burning parameters with all other sensor signals of the airplane and consider all
phases of flight, including the speed, altitude, and maneuvering of the airplane.
On ships, micro sensors must be protected against the raw environment con-
ditions on oceans. Salt water, high humidity, and changing exhaust gas conditions
require an accordingly protected case and resistance against corrosion. The most
important parameters in ship exhaust gas are NO x ,SO x , and PM. Changes over
time are slow and signals are usually without fast occurring peaks.
 
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