Lexus ES300 (2002 year). Manual — part 130

ENGINE – 1MZ-FE ENGINE

EG-43

211EG19

Actuators

Intake Air Control Valve

208EG47

To Actuator

From
Vacuum
Tank

Atmosphere

General

1) Intake Air Control Valve

The intake air control valves, which are pro-
vided in the intake air chamber, open and
close to change the effective length and intake
area of the intake manifold in 3 stages.

2) VSV (Vacuum Switching Valve)

Controls the vacuum that is applied to the ac-
tuator by way of the signal (ACIS) that is out-
put by the ECM.

3) Vacuum Tank

Equipped with an internal check valve, the vacuum tank stores the vacuum that is applied to the actuator
in order to maintain the intake air control valve fully closed even during low-vacuum conditions.

ENGINE – 1MZ-FE ENGINE

EG-44

211EG20

: Effective Intake Manifold Length

Open

Throttle
Valve

Close

2VSVs ON

Low

High

Engine Speed

211EG21

: Effective Intake Manifold Length

Open

Throttle
Valve

Close

VSV ON
(Intake Air Chamber Side)

Low

High

Engine Speed

Operation

1) Heavy Load in the Low-Speed Range

The ECM activates the VSV to match the longest pulsation cycle so that the negative pressure acts on
the diaphragm chamber of the actuators. This closes the control valves. As a result, the intake area of the
intake manifold is narrowed and the intake efficiency in the low speed range is improved due to the dy-
namic effect of the intake air, thereby increasing the power output.

2) Heavy Load in the Mid-speed Range

The ECM deactivates the VSV (intake air chamber side) to match the relatively long cycle so that atmo-
spheric air is led into the diaphragm chamber of the actuator and opens the control valve. When the con-
trol valve is open, the intake area of the intake manifold is widened and peak intake efficiency is shifted
to the mid engine speed range, thus providing greater output at mid engine speeds.

ENGINE – 1MZ-FE ENGINE

EG-45

211EG22

: Effective Intake Manifold Length

: Effective Intake Air Chamber

Open

Throttle
Valve

Close

2 VSVs OFF

Low

High

Engine Speed

3) During Idling, Light Load, and High-Speed Range

The ECM deactivates the VSVs to match the relatively long cycle so that atmospheric air is led into the
diaphragm chamber of the actuator and opens the control valves. When the control valves are open, the
effective length of the intake air chamber is lengthened most and peak intake efficiency is shifted to the
high engine speed range, thus providing greater output at high engine speeds.

ENGINE – 1MZ-FE ENGINE

EG-46

208EG50

VSV

Actuator

Air Intake
Control Valve

208EG51

VSV

Vacuum Tank

Air Intake
Control Valve

Throttle
Opening
Angle

Open

Engine Speed

Air Intake Control Valve Condition

11. Air Intake Control System

General

The air cleaner inlet is divided into two areas, and an air intake control valve and an actuator have been pro-
vided in one of the areas.
As a result, a reduction in intake noise in the low-speed range and an increase in the power output in the
high-speed range have been realized.

Layout of Components

Operation

When the engine is operating in the low-to mid-speed range, this control operates the air intake control valve
to close one side of the air cleaner inlet.
When the engine is operating in the high-speed range, this control operates the air intake control valve to
open both side of the air cleaner inlet to effect the intake of air.