TM
55-1730-229-12
AG
320A0-OM-000
TO
35C2-3-473-1
TM
1730-12/1
c. GTE Control System. (See fig-
(2) Throughout engine start and
ure FO-3.1 The control system consists
run operations, the ECU monitors the en-
of the electronic control unit (ECU),
gine low oil pressure (LOP) switch, high
starter latching relay 3K2, starter con-
oil temperature (HOT) switch, exhaust
tactor K4, 95 percent enable relay 3K1,
gas temperature (EGT) thermocouple, and
compartment temperature switch S1, speed
monopulse speed sensor. Prior to engine
sensor, low oil pressure switch, hot oil
start, the LOP switch is closed and
temperature switch, thermocouple, steer-
provides a ground return (via diode TB3-
ing diodes (TB1-CR1, TB2-CR2, TB3-CR3
CR8) to illuminate the control panel LOW
through CR8, and 1CR9) and associated
OIL PRESS lamp 1DS10.
When the engine
control panel switches and instruments.
is started and engine oil pressure rises
to 31 psi, the LOP switch opens to
(1) When system power output
extinguish the LOW OIL PRESS lamp. The
switches (control panel PNEUMATIC POWER
HOT switch is closed when engine oil
1S8, AC POWER 1S10, and DC POWER 1S12,
temperature is below 275F, and opens
and hydraulic module POWER switch 4S1)
above 275F.
The thermocouple gen-
are all off, a ground return is provided
erates a small voltage proportional to
for the starter contactor K4 coil. En-
engine EGT. The ECU temperature sensor
gine start is then initiated by momen-
and EGT readout circuit amplifies the
tarily setting ENGINE CONTROL switch 1S1
thermocouple output to the level re-
to the START position which applies dc
quired to drive the control panel EGT
control power to activate starter latch
meter 1M1.
The EGT meter indicates
relay 3K2. DC control power is then ap-
exhaust gas temperature in degrees
plied via the latch relay to the auxil-
fahrenheit.
The monopole speed sensor
iary fuel pump and the ECU.
When the
generates a signal proportional in fre-
ENGINE CONTROL switch is released to the
The ECU con-
quency to engine speed.
RUN position, dc control power is ap-
verts the speed sensor frequency to a dc
plied by EMERG STOP switch S2 and relay
voltage to drive the control panel %RPM
3K2 to latch the relay on. The ECU ap-
meter 1M2.
The %RPM meter indicates
plies dc power to activate starter con-
engine speed as a percentage of normal
tactor K4.
Contactor K4 then connects
full-load speed (58,667 rpm).
the battery output to the engine starter
which motors (cranks) the engine.
The
contactor also applies battery power
(3) The ECU uses engine speed
via diode TB2-CR2 to illuminate control
to control start and run events as fol-
lows :
panel STARTER ON light 1DS2.
Engine
Speed (rpm>
Event
Opens fuel shutdown solenoid (section XI>
10%
Activates engine ignition unit (section XIII)
Modulates fuel control torque motor (section XI)
25-95%
Deactivates starter contactor K4 (section XIII)
60%
Enables load control valve (LCV) (section XII)
95%
Disables engine ignition unit (section XIII)
Enables engine hour meter
4-162
