Volvo 819 E Service Manual page 54

28
Group Ignition systems
Design and function -
•
A
EZ-118K
EZ-1 18K -Idling compensation
EZ-118K may be provided
mission and/or air conditioning. If ei ther
to compensate for the higher engine load.
A. Certain models equipped with automatic transmission are provided with a function which advances
when a drive posit ion
Th e starting interlock switch
position R. D, 2 or 1. This
unit (1). The con trol
is idling .
B. Certain models equipped
AC compressor is switched
system.
The timing advance terminal
pressor (23), and receives a
then advances the timing
On the B 230 K eng ine,
variants or 85"C on
.. Idling compensation operated bv the ignition system control unit is not required on engines on which
to the fuel system control unit (CIS
air, well as additional
85
52
System descriptions
I
with one or two idling compensa tion functions ifthe car is equipped
function is activated, [he
is selected , to compensa
(2 1) opens the
closes the relay contacts,
unit will advance the timing if
with air conditioning
in, thereby preventing
on the control unit
12 V supply when the pressure
if the idling switch
the above compensation
1987 and later variants.
system) or to
l uel, is supplied to the engine
control
te for the increased load
relay coi l (22) ground connection when the
supplying 12 V t
the idling (air con trol)
are provided with a function which advances the
a fall in idling speed
is connected to the electromagnetic
(1)
switch 124} closes
also indicates that the
functions intervene only if
a special CIS control unit.
to compensate for
B
with automatic trans-
unit will advance the timing at
imposed by the torque
gear selector is
o the timing advance terminal
switch (19) also indicates
while maintaining the
clutch circuit on
to energize the clutch.
engine is idling.
the engine temperature exceeds 75"C
the idling
On engines of this type. the
the increased load.
23
id ling by
the timing
converter.
moved t o
on the control
that the engine
tim ing when the
capacity of the AC
the com-
The control unit
on
valve is
CIS valve ensures that