Perkins 1204F-E44TA Systems Operation Testing And Adjusting page 62

62
Engine Operation
ECM
Illustration 55
Typical example
The Electronic Control Module (ECM) (1) functions
as a governor and a computer for the fuel system.
The ECM receives signals from the sensors in order
to control the timing and the engine speed.
The electronic system consists of the ECM, the
engine sensors, and inputs from the parent machine.
The ECM is the computer. The personality module is
the software for the computer. The personality
module contains the operating maps. The operating
maps define the following characteristics of the
engine:
• Engine rating
• Torque curves
• High and low idle speed (rpm)
• Emissions
• Injection timing
The factory passwords restrict changes to authorized
personnel. Factory passwords are required to clear
any event code. Refer to Troubleshooting, "Factory
Passwords" for more information on the passwords.
This document has been printed from SPI2. NOT FOR RESALE
The ECM has an excellent record of reliability. Any
problems in the system are most likely to be the
connectors and the wiring harness. The ECM should
be the last item in troubleshooting the engine.
The programmable software contains all the fuel
setting information. The information determines the
engine performance.
Flash programming is the method of programming or
updating the programmable software. Refer to
Troubleshooting, "Flash Programming" for the
instructions on the flash programming of the
programmable software.
The ECM is sealed and the ECM needs no routine
adjustment or maintenance.
Engine Speed
The electronic controls determine the injection timing,
the amount of fuel that is delivered to the cylinders
and the intake manifold pressure if an electronically
controlled wastegate is installed. These decisions are
based on the actual conditions and the desired
conditions at any given time.
The ECM has software that compares the desired
engine speed to the actual engine speed. The actual
engine speed is determined through the crankshaft
speed/timing sensor and the camshaft speed/timing
sensor. If the desired engine speed is greater than
g01926054 the actual engine speed, the ECM will instruct the
electronic unit injector to inject more fuel in order to
increase engine speed.
Timing Considerations
Once the ECM has determined the amount of fuel
that is required, the software must determine the
timing of the fuel injection. Fuel injection timing is
determined by the ECM after considering input from
the following components:
• Engine coolant temperature sensor
• The sensor for the intake manifold air temperature
• The sensor for the intake manifold pressure
UENR4490-01