Description
NHEC0596
SYSTEM DESCRIPTION
NHEC0596S01
Sensor
Input Signal to ECM
ECM func-
tion
Actuator
Mass air flow sensor
Amount of intake air
VIAS con-
trol
VIAS control solenoid valve
Throttle position sensor
Throttle position
Accelerator pedal position sensor
Accelerator pedal position
Ignition switch
Start signal
Crankshaft position sensor (POS)
Camshaft position sensor (PHASE)
Engine speed
Engine coolant temperature sensor
Engine coolant temperature
SEC916C
When the engine is running at low or medium speed, the power
valve is fully closed. Under this condition, the effective suction port
length is equivalent to the total length of the intake manifold collec-
tor’s suction port including the intake valve. This long suction port
provides increased air intake which results in improved suction
efficiency and higher torque generation.
The surge tank and one-way valve are provided. When engine is
running at high speed, the ECM sends the signal to the VIAS con-
trol solenoid valve. This signal introduces the intake manifold
vacuum into the power valve actuator and therefore opens the
power valve to two suction passages together in the collector.
Under this condition, the effective port length is equivalent to the
length of the suction port provided independently for each cylinder.
This shortened port length results in enhanced engine output with
reduced suction resistance under high speeds.
GI
MA
EM
LC
FE
AT
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
VARIABLE INDUCTION AIR CONTROL SYSTEM (VIAS)
Description
EC-677