DU - Display Unit
The DU is an instrument panel which shows engine
working values graphically on an LCD screen. It con-
sists
of
an computerised unit for permanent installation
in a control panel.
The display communicates via the CAN link. It is con-
nected to the CAN link between the engine control unit
and the CIU or DCU.
Monitoring
- Engine speed, boost pressure, boost temperature,
coolant temperature, oil pressure, oil temperature,
fuel pressure, engine hours, battery voltage, instan-
taneous fuel consumption and average fuel con-
sumption (trip fuel).
Diagnostics
- Shows active fault codes in plain language.
Fuel control
The engine’s fuel requirement is analyzed up to 100
times per second (depending on engine rpm). The
engine’s injection amount and injection timing is con-
trolled electronically via fuel valves on the unit injec-
tors.
This means that the engine always receives the correct
volume of fuel in all operating conditions, which offers
lower fuel consumption, minimal exhaust emissions
etc.
The control unit checks and controls the unit injectors,
to ensure that the correct volume of fuel is injected into
each cylinder. It calculates and sets the injection angle.
The control is primarily performed using the speed
sensors and the combined sensor for boost pressure/
boost temperature.
The control unit affects the unit injectors via an elec-
tronic signal to the unit injectors’ electromagnetic fuel
valve, which can open and close.
When the fuel valve is open, fuel flows past, through
the unit injectors’ holes and continuing out through the
fuel channel. Fuel is not sprayed into the cylinder in this
position.
When the fuel valve is closed, pressure is built up by
the mechanically driven pump piston in the unit injec-
tor. When sufficient pressure has developed, fuel is
injected into the cylinder via the unit injector’s injector
section.
The fuel valve is re-opened and pressure in the unit
injector decreases at the same time as the fuel injec-
tion to the cylinder stops.
P0002061
30-0 General
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