EMISSION AND
EVAPORATIVE
LOSS
CONTROL
SYSTEMS
14
Fig.
15
Contact
type
throttle
switch
Fig.
16
Potentiometer type throttle switch
2163
Throttle Switches
Throttle switches
form
'part
of
the
electronic
control
for
the
fuel injection system and provide the
E.C.U.
with
information
on throttle operating conditions, Two types of switches can
be
used dependant upon the type
of
information required by
the
E.C.U.
to perform its function.
A
contact type switch
is
fitted to TA? models and
is
located
on the throttle body
in
the engine compartment. The sWitch
contacts close when the accelerator pedal
is
fully depressed.
signalling to the EC.U. to lengthen the
time
that the main
injectors are 'open', thus supplying extra fuel for the
acceleration required.
A potentiometer type switch
is
fitted to
TRB
and Rover
3500
models on the engine plenum chamber
In
Ime
With
the
throttle input spindle, This switch
is
a simple electrical
potentiometer (variable resistance) whose electrical signal to
the
ECU
depends upon the position of the throttle spindle
and hence the accelerator pedal. The
E.C.U
will
detect
changes in throttle position
by
the voltage output from the
potentiometer. Using this together
With
information from the
other sensors it
will
adjust the fuel Input accordingly. either
for degrees of acceleration and deceleration or for constant
engine speed, When a very sudden acceleration
IS
Signalled
to the
E,C.U.
by the throttle potentiometer. all Injectors are
pulsed
to
operate once simultaneously to ensure adequate
engine response.
To Next Page
Loading...
