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ENGINE 1.3L QUADRAJET (90PS)
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3A.1.8 ENGINE MANAGEMENT SYSTEM
3A.1.8.1 SYSTEMOVERVIEW
An electronic control system supervises and
governs all engine parameters to optimise
performance and fuel consumption by means of a
real-time response to different service conditions.
Diesel engines are equipped with a COMMON
RAIL type injection system. This features the use of
an electronically controlled high injection pressure.
The supply of fuel, known as the pilot injection, is
optimized by the electronic control unit by means of
the injector rather than managed by the pump.
In this 4 valve per cylinder version, the common
rail injection system uses Multijet technology: i.e.
during each engine stroke, it carries out more than
the two injections normally used: it performs two pre-
injections (before the piston is at top dead centre),
one main and two post-injections.This solution
improves fuel consumption, noise levels and
performance because it allows better control of
temperature in the combustion chamber by lowering
the maximum value and extending the optimum
combustion area.
Depending on the signals received from
numerous sensors, the control unit controls the
injectors connected to it managing the following
systems :
Q
fuel supply;
Q
air supply;
Q
heater plugs;
Q
accelerator pedal;
Q
engine cooling;
Q
fuel pre-heating;
Q
Emission control (lambda sensor).
The system is also controlled by dedicated relays in
the engine bay control unit. Lines supplying the
control unit and various system components (sensors
and actuators) are protected by dedicated fuses that
are also located inside the engine bay.
3A.1.8.2 FUNCTIONAL DESCRIPTION
This section contains the circuit layout functions
of the various components involved in engine
management system. This information gives an idea
on the working of this system.