Installation manual
,
DATA
LOGGING
(TROUBLESHOOTING
AID)
Lambda
Lambda
represents
the ratio
of
the
amount
of oxygen actually present
in
a combustion chamber
compared
to
the
amount that should
have
been
present in order to obtain
"perfect~'
combustion.
Thus,
when
a mixture contains exactly
the
amount of oxygen required to burn the
amount
of
fuel
present,
the
ratio
will
be
one
to
one
and
lambda
will
equall.OOO.
If
the
mixture contains
too
much
oxygen
for
the amount of
fuel
(a
lean
mixture), lambda will
be
greater than
1.000.
If
a
mixture
contains
too little oxygen for
the
amount
of
fuel
(a rich mixture), lambda will
be
less
than
1.000.
We
all
know
that perfect combustion
requires
an
air/fuel
ratio
of
approximately
14.7:1
(by
weight)
under
normal conditions.
Thus
a
lean
air/fuel
ratio
of,
say,
16:
1 would translate
to
a
lambda
value
of 1.088.
(To
calculate,
divide
16
by
14.7.)
A lambda of
.97
would
indicate
an
air/fuel
ratio
of
14.259:1
(derived by multiplying
.97
by
14.7).
In
our applications
we
want to see a
lambda
reading
around
1.000.
Because
of
the
combustion
involved
this
number will constantly
be
changing, ideally you should
see
the value
for
lambda
fluctuating slightly above and below
the
1.000
target.
Immediately after a startup it
is
typical
to
see
rich
readings
for
lambda. This is part of
the
startup
process
and
usually takes a couple
of
minutes
for
sensors
to
warm
up
and
take control of the air
fuel
mixture.
If
you
see
a problem in this area first
check
the
Wideband
heater values
to
make sure
that
the
heater
is
working.
Remember that it
takes
about three minutes after starting an engine
for
it
to
be
totally
in
control.
Physically remove
the
sensor and
checl_<
it
for
corrosion or build
up
of deposits
from
the
Water
being
injected through
the
exhaust.
Salt
water deposited on the
sensor
will be
very
,damaging.
If
there
is
any
evidence
of build
up,
replace
the
sensor.
After
checking
the
sensor
and
the
genset
is
running
too
rich, check
the
air intake
screens
and
spark
plugs
to
make
sure
they
are
Clean
and
functioning properly.
If
the
genset
is
running
too
lean,
check
the
fuel
levels
and
the
quality
of
the
fuel.
Water
in
the
gas
is
no
good
and
will cause
the
genset
to
run
lean.
lp
Current
This
is
the
electrical
value
equivalent of
the
Lambda
reading.
There
is
not much
to
learn from
this
number.
Lambda PW Trim
This
is
the
fueling
trim percentage that
the
wideband
oxygen
sensor
is
contributing. In most
cases
15%
is
the
maximum.
Wideband P, I & D Term
These
values
are
the
Wideband
Sensor
Heater temperature control
terms.
These
values
will
be
constantly
changing.
It
is
more
important
to
look
at
the
WB
Current
Temp
value.
Lambda P & I Term
These
values
are
the
lambda value controlling
terms.
Their
job
is
to
keep
the
lambda
reading
at
1.000
by
enriching
or
enleaning
the
fueling.
NBSTT
(Narrowband
Short
Term
Trim)
If
your
genset
is
equipped
with a narrowband
oxygen
sensor,
this
will
be
the
value
of its contribution.
Max
contribution
is
1%.
Engines & Generators
33