Toyota COMPUTER-CONTROLLED SYSTEM - Page 98

ESA - Ignition Circuit r y
2 . DLI (DISTRIBUTORLESS IGNITION) SYSTE M
DLI is an electronic spark distribution system
which distributes high voltages directly from the
ignition coils to the spark plugs without the need
of a conventional distributor . It differs from the
conventional type of ignition system as shown
below :
Spark
Distributor plug
s
EC U
DLI SYSTE M
Ignition
coil s
Ignition
switc h
Battery
OHP 6 3
Drive
circu
i
Driv e
circui t
Drive
circuit
OHP 63
CONVENTIONAL IGNITION CIRCUITRY FOR TCC
S
Engine EC U
Input
circui t
Dwell angle
control
circuit
Y
V
V
~
a
OHP 6 3
In the DLI, the igniter is connected to the Engine
ECU as shown in the figure above . There are
three ignition coils : one for cylinders No . 1 and
No
. 6, one for cylinders No . 2 and No . 5, and one
for cylinders No . 3 and No . 4 . The ECU sends
cylinder identification signals (IGDA and IGDB)
and the IGT signal to the igniter in accordance
with the G 1, G2 and NE signals from the cam posi-
Igniter
tion sensor which detects the crankshaft angle,
engine speed and various sensors .
The igniter distributes the primary current to the
three ignition coils based on these signals . For
this reason, the spark plugs in cylinders No . 1
and No . 6 fire simultaneously, as do those in
cylinders No . 2 and No . 5 and cylinders No . 3
and No . 4 . In other words, each spark plug is
ignited two times in one cycle .
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