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WG1605-G-E3,WG1605-L-E3,WG1605-GL-E3, DM
ENGINE SENSOR GROUP
To maintain fuel control, and insure the system
provides the optimum performance, the ECM depends
on sensors installed in the engine and fuel system, to
provide input to the ECM, for calculating fuel delivery, as
well as fuel system diagnostics. This section will provide
the technician, with the understanding of the function of
each sensor.
TEMPERATURE MANIFOLD ABSOLUTE PRESSURE
(TMAP)
The TMAP sensor is a combination sensor, and
provides the ECM with the Intake Air Temperature (IAT),
and the Manifold Absolute Pressure (MAP). The ECM
uses the intake air temperature to correct fueling based
on the density of the air.
The MAP portion of the TMAP sensor provides the
ECM with a measurement of the pressure in the intake
manifold. During the start up, the MAP provides the ECM
with the barometric pressure, to allow the ECM to adjust
fueling, based on barometric pressure. Once the engine
has started, the ECM uses the MAP to measure the load
on the engine, and make fuel and RPM corrections, to
compensate for changing load conditions.
In Kubota fuel system design, the TMAP is mounted
to the intake manifold, The TMAP is a 5.00 V reference
signal sensor, which operates by the resistance change
in the sensor, to output a reference voltage for the ECM
to use. The sensor can be a 0 to 5.00 V which is supplied
by the engine. During the development phase of the
system, the minimum and maximum thresholds of
operation are determined, and are part of the fuel
calibration and diagnostics, programmed into the ECM.
These thresholds are used to establish the point at which
the ECM will set the MIL light, to indicate that a fault has
been detected in the fuel system.
ENGINE COOLANT TEMPERATURE (ECT)
The ECM monitors the engine coolant temperature,
through the ECT sensor mounted in the engine. The
ECM uses this sensor input to make corrections in
fueling, and to protect the engine from overheating
during normal operation.
In Kubota fuel system designs, the ECT is mounted
in the water flange, and is usually supplied by Kubota.
The ECT is a 5.00 V reference signal sensor, which
operates by the resistance change in the sensor, to
output a reference voltage for the ECM to use. The
sensor can be a 0 to 5.00 V which is supplied by the
engine. During the development phase of the system,
the minimum and maximum threshold of engine
temperature, during normal operation, are determined
and are part of the fuel calibration and diagnostics,
programmed into the ECM. These thresholds are used
to establish the point at which the ECM will set the MIL
light, to indicate that a fault has been detected in the fuel
system. Should the temperature be exceeded, the ECM
will first reduce the engine performance capabilities,
often referred to as "limp home", which allows the
operator to move the equipment to a facility for repair, or
safely shut down the system. In the event the
temperature continues to rise, the ECM will shut down
the engine in a specified period of time, after the "limp
home" strategy has been activated.
ENGINE OIL PRESSURE (EOP)
The ECM monitors the engine oil pressure, through
the EOP sensor, mounted in the engine. The ECM uses
this sensor input, to protect the engine from damage,
from the lack of oil in the crank case.
In Kubota fuel system designs, the EOP is mounted
in the cylinder block, and is supplied by Kubota. The
EOP is a 5.00 V reference signal sensor, which operates
by the resistance change in the sensor, to output a
reference voltage for the ECM to use. The sensor can be
a 0 to 5.00 V which is supplied by the engine. During the
development phase of the system, the minimum and
maximum threshold of engine temperature, during
normal operation are determined, and are part of the fuel
calibration and diagnostics, programmed into the ECM.
These thresholds are used to establish the point, at
which the ECM will set the MIL light, to indicate that a
fault has been detected in the engine. Should the
pressure be exceeded or fall below the minimum
pressure, the ECM will shut down the engine in a
specified period of time.
THROTTLE POSITION SENSORS 1 & 2 (TPS 1&2)
Kubota fuel systems use an Electronic Throttle Body
(ETB) for speed and load control. Internal to the ETB, are
two Throttle Position Sensors (TPS), which provide an
"actual position" of the throttle plate. During the
calibration development, the throttle blade variation,
from actual to command, is defined. A maximum
variation threshold is determined and included in the
calibration, this threshold insures that the variation
between actual and command do not vary above this
threshold. In the event the variation exceeds the
threshold, the ECM will command the ETB to idle, or
shutdown the engine. The ECM will also set a diagnostic
code, and turn on the MIL light
1-56
ECM SYSTEM
KiSC issued 12, 2016 A
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