Toyota COMPUTER-CONTROLLED SYSTEM Training Manual page 134

OTHER CONTROL SYSTEMS - T-VI S
T-VIS (TOYOTA-VARIABLE INDUCTION SYSTEM )
GENERA L
a . The intake manifold passage leading to each
cylinder is divided into two parts . One of
these (the variable induction passage) is
provided with an intake air control valve .
This valve opens and closes in accordance
with the speed of the engine, thus acting as
a variable induction valve . This makes it
possible to improve engine performance in
the low-speed range without sacrificing the
high engine speed and output that are
distinctive features of engines with four
valves per cylinder .
VS V
Intake manifol d
(air intake chamber)
T-VIS
b . The intake air control valves for all cylinders
are constructed as one unit, and are opened
and closed together by an actuator .
c . The improvement in the pe rf ormance of the
engine due to the adoption of T-VIS is shown
in the graph below .
OHP 8 8
Low
Engine speed --- High
OHP 8 8
OHP 8 8
Engine
EC U
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