Sun Microsystems MCS 2000 SL - Page 72

USE
OF
LAMBDA
MEASUREMENT
Sun
now
provides
Lambda
and
AFR
measurements
on
all
gas
analysers which
can
measure
four
gases.
The
method
adopted fcjr Lambda
measurement is
derived
from
the
Spindt
formula,
which
takes
account
of CO,
HC,
CO2 and
02.
This formula
has
been adopted
as
it is the most comprehensive,'and
allows
for
Lambda
(AFR)
measurement
both, before and after
the
cata'lytic
converter,
with the
same result. It is
expected that the majority of
"Open
Loop"
systems will
have
an exhaust
tapping
before
the catalytic
converter
in
order that fuel mixtures
may be
adjusted accurately
to
Stoichiometric.
On
"Closed
Loop" systems, some manufactures
are
fitting
a
tapping
before the
catalytic converter.
To test an
engine
fitted with
a
cata'lytic
converter
and/or a Lambda sensor,
the
engine should be running
at 3000
rpm for
approximately three
minutes
to
ensure that
jt
is at
operating temperature. If monitoring
exhaust
gas you
will see the
change
in
values as the
catalytic converter comes into
operation.
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