Jacobsen Eclipse 322, Руководство по ремонту

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ELECTRICAL
4222983 Second Edition 4-37
4
Gasoline Engine Circuit—Theory of
Operation
Power Circuit
Unswitched 48V power is available from stud 3 through
150A fuse (F8) and 0.02 ohm resistor (R6) to key switch
terminal A and liquid crystal display (LCD) terminal
J11-8.
When the key switch is turned to the run position, 48 volts
is provided from key switch terminal B to liquid crystal
display (LCD) ignition terminal J11-5, powering up the
LCD.
With the LCD powered up, a ground is provided from the
LCD switched power contactor output terminal J11-10 to
the power distribution unit (PDU) terminal J1-4. With a
ground provided to J1-4, the 12 and 48 volt switched
power contactors are energized.
With the PDU 12 volt switched power contactor
energized, 12 volts is provided through 0.02 ohm resistor
(R12) to the main control unit (MCU) 12 volt power input
terminal J2-8. PDU terminal J1-5 also provides 12 volts
to splice E and then from splice E, 12 volts is provided to
MCU 12 volt power input terminal J2-6. With the PDU 48
volt switched power contactor energized, 48 volts is
provided to circuit breaker (F4) and MCU 48 volt power
input terminal J2-7, powering up the MCU.
Start Circuit
When the key switch is turned to the start position, 48
volts is provided from key switch terminal C to the LCD
display start input terminal (J12-2), activating the input.
With the input activated, the LCD display communicates
the key switch status to the main control unit (MCU)
through the controller area network (CAN).
With the key switch (status) in the start position, 12 volts
is provided from the MCU fuel hold output terminal (J2-4)
to the fuel shutoff solenoid, energizing the solenoid. With
the solenoid energized, the fuel shutoff solenoid plunger
retracts.
The MCU magneto output terminal (J2-1) un-grounds the
ignition modules, allowing the modules to produce spark
when the engine is turning.
The MCU start output terminal J2-2 provides 12 volts to
start relay terminal 86, energizing the relay. With the start
relay energized, voltage is switched between relay
terminals 30 and 87 and supplied to the starter motor
solenoid, energizing the solenoid. With the starter
solenoid energized, voltage is switched between the
starter solenoid contacts to the starter motor, engaging
the motor. Diode V4 conducts to ground the reverse
voltage generated when the start relay is de-energized.
The MCU will only engage the starter for 10 seconds. If
the engine fails to start, the key switch must be turned to
the off position before attempting to start again.
Run Circuit
The engine continues to operate when the key switch is
in the run position.
If the engine oil pressure drops below 7 psi (1.72 bar) the
engine oil pressure switch closes.
With the engine oil pressure switch closed, a ground is
provided to the MCU oil pressure input terminal (J3-7),
activating the input. With the oil pressure input activated,
the MCU instructs the LCD to turn on the low oil pressure
light through the controller area network (CAN). After a
timed delay, the MCU will de-energize the fuel shutoff
solenoid and ground the ignition modules, shutting off the
engine.
When the key switch is turned to the off position, the LCD
provides a 10 second power down delay (to prevent
engine backfire).
Charging Circuit
The charging circuit is a permanent magnet and stator
design. As the flywheel turns, the magnets pass the
stator coils, producing AC voltage. The AC voltage is
rectified by the voltage regulator and DC voltage is
produced. The DC voltage is used to charge the battery.
When the battery voltage is low, the voltage regulator
supplies a regulated voltage to charge the battery. When
the battery is fully charged, the regulator stops providing
regulated voltage to the battery.
When the 12V battery drops to a specific voltage, the
MCU instructs the LCD to turn on the 12V low battery
light through the controller area network (CAN).