G And Ne Signal Generators; In-Distributor Type - Toyota COMPUTER-CONTROLLED SYSTEM Training Manual

0 ELECTRONIC CONTROL SYSTEM - G and NE Signal Generator s
G AND NE SIGNAL GENERATOR S
The G and NE signals are generated by the
timing rotors or signal plates and the pickup
coils . These signals are used by the Engine ECU
to detect the crankshaft angle and engine speed .
These signals are very important not only for the
EFI system but also for the ESA system .
The sensors which generate these signals can be
divided into the following three types depending
on their installation position, but their basic
construction and operation are the same :
• In-distributor typ e
• Cam position sensor type
• Separate typ e
1 . IN-DISTRIBUTOR TYP E
The conventional governor advance and vacuum
advance mechanisms have been eliminated in
the distributor used with the TCCS engine
control system, since spark advance is controlled
electronically by the Engine ECU . The distributor
in the engine control system contains the timing
rotors and pickup coils for the G and NE signals .
The number of teeth on the rotor and the
number of pickup coils differ depending on the
engine . Below, we will explain the construction
and operation of the G and NE signal generators
that use a single pickup coil and a 4-tooth rotor
for the G signal, and a single pickup coil and 24-
tooth rotor for the NE signal .
G SIGNA L
The G signal informs the Engine ECU of the
standard crankshaft angle, which is used to
determine the injection timing and ignition
timing in relation to the TDC (top dead center) of
each cylinder .
The components of the distributor used to
generate these signals are as follows :
1) The G signal timing rotor, which is fixed to
the distributor shaft and turns once for
every two rotations of the crankshaft .
2) The G pickup coil, which is mounted on the
inside of the distributor housing .
The G signal timing rotor is provided with four
teeth which activate the G pickup coil four times
per each revolution of the distributor shaft,
generating the waveforms shown in the chart
shown below . From these signals, the Engine ECU
detects when each piston is near TDC (ex-
ample : BTDC10°CA*) .
" Depending on engine models .
1 turn of timing roto r
1800
CA (crankshaft angle )
G signal
OHP 1 6
24