Group
28
Ignition
systems
Design
and
function
Compensation
functions
147 101
Knock-controlled
fuel
enrichment
Knock-contro
l
led
fuel
enrichment
means
that
the
injector
opening
period
is
extended
to
enrich
the
fuel/air
mixture,
reducing
th
e
combustion
temperature
and
br
in
ging
the
uncontrolled
combustion
under
control.
The
function
is acti-
vated
if
the
igni
t
ion
system
control
unit
detects
that
knock is
occurring
in
all
cylinders
above
a
certain
threshold
value.
On
re
ceiving
a
signal
from
the
knock
sensor
(2)
and
having
established
that
knock
is
present
in
all
cylinders,
the
con-
trol
unit
(1)
connects
a
terminal
on
the
fuel
injection
system
contro
l
unit
(3)
to
ground,
causing
the
latter
to
transmit
a
signa
l
to
the
injectors
(4)
to
extend
the
opening
period.
Kno
ck
-con
trolled
fuel
enrichment
is
a
feature
of
EZ-117K on
the
B230FT
engine,
and
of
all
variants
of
EZ-11SK
and
EZ
-1
16K.
* The function
is
activated only within a certain speed and load range, in addition to which acertain average knock-controlled retar-
dation must already have been applied in all cylinders. The following conditions
are
requ ir
ed
for the intervention of the knock-
controlled fuel enrichment function on the various ignition systems/engines:
-
EZ
-l17K
on
B230FT:
6"
retardation in all cylinders in response to knock detector signals.
-
EZ
-
115K
on B280E
/F:
Retardation of at least
10
° in all cylinders
in
response to knock detector signals
at
engine speeds above
3800
r/min and above a certain minimum load.
-
EZ
-1
16K
on 8
234
F:
Retardation of
at
least
3--4
0in all cylinders
in
response to knock detector signals
at
engine speeds above
3800
r/min and above a certain minimum lo
ad
.
39
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