Toyota COMPUTER-CONTROLLED SYSTEM Training Manual page 130

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ACIS (ACOUSTIC CONTROL INDUCTION SYSTEM )
The ACIS changes the effective length of the here for convenience "Type 1" and "Type 2" .
intake manifold in order to increase air intake They differ both in their basic design and in the
efficiency . There are two types of ACIS, called number of air control valves used .
1 . TYPE 1
GENERA L
This type of ACIS has only one air control valve . distributor . This air control valve is opened and
This is located in the air intake chamber and is closed by the Engine ECU via a VSV and an
used to increase the intake efficiency of the air actuator .
supplied to the cylinders . It does this in response This makes it possible to improve engine
to changes in the throttle opening (VTA) signal performance at both low and high engine
sent from the throttle position sensor, and the speeds .
engine speed (NE) signal sent from the
Thro
tt
le valve Air control valv e
Distributo r
e1Z 11
F
VTA
N E
Engine ECU
4
Actuator
OHP 8 4
Vacuum tan k
Vs V
~
a~ b tf664@
Air control valve Air control valv e
closed
OTHER CONTROL SYSTEMS - ACI S
Air contro l
\valve
Actuator
VsV
Vacuum
tank OHP 84
Thro
tt
le
position
senso r
Low
Engine speed
~
High
OHP 8 4
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