Timing Considerations
Once the governor has determined the amount of fuel
that is required, the governor must determine the
timing of the fuel injection. Fuel injection timing is
determined by the ECM after considering input from
the following components:
• Coolant temperature sensor
• Intake manifold air temperature sensor
• Intake manifold pressure sensor
The ECM adjusts timing for optimum engine
performance and for fuel economy. Actual timing and
desired timing cannot be viewed with the electronic
service tool. The ECM determines the location of top
center of the number one cylinder from the signals
that are provided by the engine speed/timing sensors.
The ECM determines when injection should occur
relative to top center. The ECM then provides the
signal to the injector at the desired time.
Fuel Injection
The ECM sends a high voltage signal to the injector
solenoids in order to energize the solenoids. By
controlling the timing and the duration of the high
voltage signal, the ECM can control the following
aspects of injection:
• Injection timing
• Fuel delivery
The flash file inside the ECM establishes certain limits
on the amount of fuel that can be injected. The “FRC
Fuel Limit” is a limit that is based on the intake
manifold pressure. The “FRC Fuel Limit” is used to
control the air/fuel ratio for control of emissions. When
the ECM senses a higher intake manifold pressure,
the ECM increases the “FRC Fuel Limit” . A higher
intake manifold pressure indicates that there is more
air in the cylinder. When the ECM increases the
“FRC Fuel Limit” , the ECM allows more fuel into the
cylinder.
The “Rated Fuel Limit” is a limit that is based on the
power rating of the engine and on the engine rpm.
The “Rated Fuel Limit” is like the rack stops and the
torque spring on a mechanically governed engine.
The “Rated Fuel Limit” provides the power curves
and the torque curves for a specific engine family and
a specific engine rating. All of these limits are
determined at the factory. These limits cannot be
changed.
Customer Parameters and Engine Speed
Governing
A unique feature with electronic engines is customer
specified parameters. These parameters allow the
owner of the machine to fine-tune the ECM for engine
operation. Fine-tuning the ECM allows the machine
owner to accommodate the typical usage of the
machine and the power train of the machine.
Many of the customer parameters provide additional
restrictions on the actions that will be performed by
the ECM in response to input from the operator. The
“PTO Top Engine Limit” is an engine rpm limit that is
used by the ECM to limit the fuel during operation of
the PTO. The ECM will not fuel the injectors above
this rpm.
Some parameters are intended to notify the operator
of potential engine damage (engine monitoring
parameters). Some parameters enhance fuel
economy (machine speed, engine speed limit, and
idle shutdown). Other parameters are used to
enhance the engine installation into the machine.
Other parameters are used to provide engine
operating information to the owner of the machine.
Other ECM Functions for
Performance
The ECM can also provide enhanced control of the
engine for machine functions such as controlling the
cooling fan. Refer to Troubleshooting, “Customer
Specified Parameters” for additional information .
ECM Lifetime Totals
The ECM maintains total data of the engine for the
following parameters:
• “Total Operating Hours”
• “Engine Lifetime Hours”
• “Total Idle Time”
• “Total Idle Fuel”
• “Total Fuel”
• “Total Max Fuel”
• “Engine Starts”
• “Lifetime Total Engine Revolutions”
• “Average Load Factor”
The “Total Operating Hours” is the operating hours
of the engine. The operating hours do not include the
time when the ECM is powered but the engine is not
running.
The “Engine Lifetime Hours” is the number of hours
when electrical power has been applied to the engine.
These hours will include the time when the ECM is
powered but the engine is not running.
“Total Idle Time” and “Total Idle Fuel” can include
operating time when the engine is not operating
under a load.
Fuel Information can be displayed in US gallons or in
liters.
“Total Fuel” is the total amount of fuel that is
consumed by the engine during operation.
8 UENR0678
Electronic Troubleshooting
Find manuals at http://best-manuals.com/search?&s=PER-1106
To Next Page
Loading...
