APRILIA RST mille Futura 2001 Service Manual page 143

FUEL SYSTEM
RST mille
USA
4.7.2 SENSORS
Camshaft position sensor (1)
1
Location: in the flywheel cover (2).
This is a sensor that detects the movement of the
selected phonic wheel on the crankshaft. The selected
wheel has a unique pulse length, triple the distance/
2
clearance, to act as a reference point on the wheel. Using
this reference point it is possible to calculate the
crankshaft position.
In a four-stroke engine, this alone is not enough
information about the reference point to allow us to
determine whether a cylinder near top dead center (TDC)
is in the intake or exhaust stage. To obtain this
information, it is necessary to obtain further details about
the position by applying a strategy of varying the engine
speed.
The information about the engine position is used to
determine the engine speed, and for any activities that
must be synchronized with the wheel rotation, such as
fuel injection.
Atmospheric pressure sensor
Location: inside the electronic control unit (3).
3
This sensor is connected to the air gap via a small hose.
It is a piezoelectric sensor that measures the absolute air
pressure. The measurement point is located to greatly
limit changes in pressure caused by engine induction
processes. The nominal pressure within the air gap
corresponds to the atmospheric pressure. The air gap
pressure is used to compensate for load density changes
in the fuel system.
4
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Release 00/2002 - 03