VARIABLE INTAKE-AIR SYSTEM OPERATION [L3 R.H.D.]
BUE011300020N03
Engine speed less than 4,750 rpm (variable intake air shutter valve closed)
• Intake manifold vacuum is applied to the variable intake air shutter valve by the operation of the variable intake air solenoid valve, closing the variable intake air shutter valve.
• Under this condition, the effective intake manifold length is from the intake valve to the dynamic chamber (A-C). An inertia charging effect is obtained due to this elongated intake manifold length, air intake volume in the cylinder increases, and higher torque is obtained at low to medium engine speeds.
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1
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variable intake-air shutter valve (closed)
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2
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Secondary dynamic chamber
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Engine speeds 4,750 rpm or more (variable intake air shutter valve closed)
• The variable intake air shutter valve is open.
• Under this condition, the effective intake manifold length is from the intake valve to the secondary dynamic chamber (B-C). An inertia charging effect is obtained due to this shortened intake manifold length, air intake volume in the cylinder increases, and higher torque is obtained at high engine speeds.
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1
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Variable intake-air shutter valve (open)
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2
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Secondary dynamic chamber
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