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C. General description
Three power ranges
--- The model T191LS has also a larger transport boost
power area, when the main gear is H2 or higher and
Powershift boost area, when quick---shift is 2 or 3.
The trans boost and Powershift boost power areas are
equal.
The largest Sigma Power area with all gears is in use,
when the power transferred through the power---take---
off is large enough. The symbol
is illuminated in
the instrument panel.
The principle of the turbocharged engine is that exhaust
gases from the engine cylinders drive the turbo unit which
forces air into the cylinders. This means that higher power
output can be obtained with economical fuel
consumption. On intercooler models cooled inlet air is fed
into the cylinders.
The engine induction air passes through the air filter and a
safety filter inside the air filter. The air intake system has
an effective ejector system, most of the impurities are
removed before they reach the filter by the exhaust fume
flow. The safety filter prevents the engine being damaged
if the main filter fails.
These engines have lower fuel consumption and cleaner
exhaust gases.
C 3.1.
Electronic engine manage-
ment (EEM)
The electronic engine management includes a controller
installed on the engine (EC).
The electronic engine management improves the techni-
cal features of the engine such as fuel efficiency, power,
torque and cold starting. It also reduces emissions and
noise. The cruise control for both driving speed and engi-
ne speed is also one of the engine base features.
C 3.2.
Common rail system engine
In the Common Rail tractors the injection pump has been
replaced by the high---pressure pump, which pumps the
amount of fuel to over 1000 bar pressure, to the high pres-
sure accumulator (rail), common for all cylinders. The
high---pressure fuel injects to the cylinders through the
electric controlled injectors. The engines have also four
valves per cylinder.The Common Rail system makes it
possible to develop quiet---running, economic engines
featuring, reduced emissions and noise, especially by
lower rotating speeds.
