Volvo TAMD74C, Operator'S Manual

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Presentation
What is EDC
EDC stands for Electronic Diesel Control. It is an electronic system for marine diesel engine control. The system
has been developed by Volvo Penta and covers fuel control, diagnostic function and electronic engine speed
control and shifting.
The processor
The brain of the EDC system, the processor, is en-
cased in the control module and protected against
moisture and vibration.
The processor continuously receives information
about fuel supply, engine speed, charge air pressure,
engine temperature and driver commands etc., via a
number of sensors and senders.
The information provides an exact picture of the pre-
vailing operating conditions. This makes it possible for
the processor to calculate the correct fuel volume,
check the engine condition and prevent irritating stall-
ing during backward and forward manoeuvering etc.
Fuel control
The engine fuel requirement is analyzed up to a 100
times per second. If necessary the fuel supply is ad-
justed by the electronic actuator in the fuel injection
pump.
This ensures that the engine always receives the cor-
rect volume of fuel in all operating conditions. This
means lower fuel consumption and minimal exhaust
emissions.
Diagnostic function
The task of the diagnostic function is to discover and
localize any disturbances within the EDC system, to
protect the engine and to ensure operation in event of
serious disturbances.
If a disturbance is found the diagnostic button indica-
tor in the control panel begins to flash. By pressing
the diagnostic button the operator will receive a diag-
nostic trouble code (DTC) as a guide for any fault-
tracing.
Engine speed control and shifting
The operating command is transferred to the elec-
tronic actuator in the fuel injection pump, the electron-
ic valves in the reverse gear or to the gearshift control
actuator for drive, using a potentiometer in the operat-
ing control.
The result is fast accurate throttle response and
smooth shifts.
Changing is further protected by the processor which
prevents shifting at too high engine speeds which
may cause damage to the transmission.
1. Control Module
2. Electronic actuator
3. Control panel
4. Solenoid valves
5. Potentiometer
For the location of other electrical components: See the chapter “Maintenance. Electrical components diagram”.
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