Buhler 2425 - Manual (Page 110)

SECTION 2 - OPERATION
2-52
The throttle lever, 1, in the cab of the tractor is
attached to a potentiometer (POT) in the right
hand side console. The POT sends an
electronic signal (via the tractor wire harness) to
the controller on the side of the engine, telling it
where to set the engine speed. By moving the
throttle lever, the POT signal is changed and the
module reacts accordingly to set engine speed
to match the lever position. During an engine
speed derate (engine speed reduced by the
engine control module to 1400 rpm), the module
will not recognize or react to a throttle position
above the 1400 rpm POT signal. If the throttle
lever is moved above the 1400 rpm position, the
engine will not speed up.
The engine control module controls the timing of
and the amount of fuel that is injected into the
engine via the electronic fuel injectors. This is
called fuel metering and is the basis of power
derate. Power derate will occur within a
specified time span (e.g. low engine oil
pressure) or will be gradual based on severity of
the alarm condition present on the tractor (e.g.
engine coolant temperature). The engine will
now perform to a modified horsepower curve
(20% less then maximum gross horsepower),
with the end result being that it will no longer pull
the same load at the same ground speed or at
the same working depth. The tractor may have
to be downshifted or the implement raised out of
the ground to continue operation (or both).
The Cummins engine control module is also tied
to three indicator lights on the warning light bar
of the EICS. The Module controls illumination of
these lights:
1. Engine Coolant Level
2. Yellow Engine Warning Light
3. Red Engine Warning Light
The EICS and Cummins control module
combine to protect the engine from damage by
informing the operator that a particular condition
exists using the lights, performance derate or
both lights and derate .
1
Figure 2-78
Electronic Engine
Figure 2-79
2
1
3
Figure 2-80