INTAKE-AIR SYSTEM
01–13–5
01–13
INTAKE MANIFOLD/DYNAMIC CHAMBER CONSTRUCTION [LF]
E5U011313100N01
• The intake manifold composed of the variable intake air shutter valve actuator.
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VARIABLE INTAKE AIR SYSTEM FUNCTION [LF]
E5U011300020N01
• The variable intake air system maintains high torque from the low to high engine speed ranges.
• If any of the following conditions are met, the effective intake manifold length is changed to enhance the inertia
charging effect. As a result, higher torque is obtained in all ranges.
— Engine speed is approx. 4,750 rpm or more.
— Engine speed is approx. 3,150 rpm or less and the throttle opening angle is the specified value or more.
(heavy load condition)
• For the variable intake air control, refer to CONTROL SYSTEM, Variable Intake Air Control (See 01–40–15
VARIABLE INTAKE AIR CONTROL OUTLINE [LF].)
Inertia charging effect
— Airflow in the intake air pipe pulsates according to the opening and closing of the intake valve. When the
intake valve closes, intake air is compressed near the intake valve due to inertia force. The resulting
pressure wave is reflected to the throttle valve side by the intake valve and the wave is then reflected back
to the intake valve side when it reaches the dynamic chamber. The effective intake manifold length is
controlled so that the pressure wave returns to the intake valve at the intake stroke. Due to this, air intake
volume increases, resulting in higher torque.
Effective intake manifold length
— The effective intake manifold length is the length from the intake valve to the dynamic chamber.
— The effective intake manifold length changes according to the positioning of the reflected pressure wave
transmitted through the intake air pipe by the opening and closing of the variable intake air shutter valve in
the dynamic chamber.
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VARIABLE INTAKE AIR
SHUTTER VALVE
ACTUATOR
INTAKE MANIFOLD
DYNAMIC CHAMBER
E5U113ZS5015
CLOSING AREA
OPENING
AREA*1
HIGH
HIGH
LOW
LOW
ENGINE TORQUE
ENGINE SPEED
APPROX. 4,750 RPM
OPENING AREA
: VARIABLE INTAKE AIR
SHUTTER VALVE OPEN
: VARIABLE INTAKE AIR
SHUTTER VALVE CLOSED
*1: THROTTLE OPENING ANGLE IS THE SPECIFIED VALUE OR MORE
E5U113ZS5002
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