A critical study of various types of exhaust gas analyzers for gasoline engines
<p>It is quite common practice in automotive and aircraft engine maintainence, operation, and research to employ any one of several types of instruments now on the market for determining the air-fuel ratio by exheust gas analysis. It was the purpose of this investigation to determine the most...
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| Other Authors: | |
| Format: | Others |
| Language: | en |
| Published: |
Virginia Tech
2014
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| Online Access: | http://hdl.handle.net/10919/40969 http://scholar.lib.vt.edu/theses/available/etd-02072013-040019/ |
| Summary: | <p>It is quite common practice in automotive and aircraft
engine maintainence, operation, and research to employ
any one of several types of instruments now on the market
for determining the air-fuel ratio by exheust gas analysis.
It was the purpose of this investigation to determine the
most important operating characteristics, especially range
and accuracy, of each of these types of instruments.</p>
<p>The theory underlying the operation of this kind
of apparatus was studied critically, and certain tests were
performed on representative makes in order to observe the
eperation of each type under service conditions. These
tests consisted essentially of connecting the analyzers to
the exhaust pipe of a single-cylinder engine and comparing the analyaer readings with the true air-fuel ratio determined
by accurately measuring the air and fuel supplied to the
engine while the instruments were being observed. This procedure
was repeated for a number of different carburetor
settings, all other factors being kept as nearly constant as possible during a given series of runs. The effect of variations
in engine spark advance and the pressure of the gas
supplied to the instruments was also investigated.
</p>
<p>The test revealed several interesting facts.
Study of the operating principles of the several instruments indicated that they were limited te air fue1 ratios below
about 14 to 1, and this has been conclusively proved by
these experiments. This limitation applies to thermal conductivity,
hot-wire catalytic, and relative density types. W
While the most expensive makes of instruments were not
tested, it was found that, in general, the limit of accuracy
is not greater than one-half of one air-fue1 ratio, regardless
of the operating principle employed. Large variations in
the pressure and rate of flow of the exhaust supplied to the
analyzers were found to cause ocnsiderable deviations in
those instruments which did not employ some kind of device
to insure a steady and uniform supply.</p>
<p>
Certain features of design and construction which
effect the reliability of the various types of exhaust gas analyzers are also reviewed in this thesis, and some of the more important chemical methods of analysis are treated briefly.</p> === Master of Science |
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