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DESCRIPTION & OPERATION
Page 17
For current-production engines, the EECU is
relocated to the left side of the engine (Figure 9)
and mounted on a new one-piece air inlet
manifold (Figure 13). With this relocation, the
fuel-cooled backing plate is no longer necessary
and has been eliminated. The new harness is
routed around the rear of the engine, and the
module and harness connections are mounted
vertically at the forward end of the module. This
provides an improved environment and less
chance for water infiltration at the harness
connectors.
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Figure 9 — EECU (Left-Side Mounted)
The cab-mounted Vehicle Electronic Control Unit
(VECU) provides a base for future development,
such as “total vehicle” systems and wireless
communication.
For enhanced quality, an engine-mounted EECU
allows the complete engine system (EECU,
harness and sensors) to be assembled at the
engine manufacturing/assembly plant, then
tested and verified on site. The entire engine
electronic package can be left undisturbed during
the vehicle assembly process.
With the two-module design, a more efficient and
reliable electronic communication network,
known as multiplexing, can be used. Multiplexing
essentially means that inputs and outputs to and
from one control unit are “batched” and sent as a
package to the other control unit via a single,
high-speed communication line. Inherent to this
system is a significant reduction in the length and
number of wires, specifically those which must
pass through the bulkhead, as well as the related
connections.
V-MAC III SYSTEM SENSORS
There are a total of eight engine-mounted
sensors and one vehicle-mounted sensor. Seven
of the sensors provide input for the operation of
the V-MAC III engine control system, while the
remaining two sensors provide input for the dash
gauges. The dash gauge oil temperature sensor
is optional.
The following list and Figure 10 through Figure 19
identify the nine sensors and the features and
location of each. Three of the V-MAC III sensors
will be described in detail. These are the fuel
temperature sensor and the engine speed and
engine position sensors. The engine speed and
engine position sensors are functionally similar to
the E7 RPM/TDC and TEM sensors, but are later
designs, quite different from the E7 sensors.
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Engine Speed Sensor
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Fuel Temperature Sensor
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Oil Pressure Sensor
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Ambient Air Temperature Sensor (see Note)
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Boost Air Temperature Sensor
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Dash Gauge Coolant Temperature Sensor
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V-MAC III Coolant Temperature Sensor
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Engine Position Sensor
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Dash Gauge Oil Temperature Sensor
(optional)
1. Engine ECU
2. Air Inlet Manifold
5_106_00.bk Page 17 Friday, August 4, 2000 11:17 AM
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