System Description
SYSTEM DIAGRAM
SYSTEM DESCRIPTION
This system switches the length of intake air path according to the low-to-medium speed range or high speed range. Engine torque is increased in the low-to-medium speed range and the engine output is improved in the high speed range.
Low and medium speed range
Intake manifold tuning (IMT) valve is closed when the engine speed is less than 5, 050 RPM. At this condition, the effective intake port length is from inlet port of the manifold to intake valve. With this length, an effect of inertia air induction is obtained so that induction air efficiency increases which can generates high torque.
High speed range
When engine speed is 5, 050 RPM or more, ECM turns ON the intake manifold tuning valve motor to open the intake manifold tuning valve. At this condition, the effective intake port length is from the intake manifold tuning valve to the intake valve. With this shorter length than the length in lower engine speed, an effect of inertia air induction is obtained in high speed side engine condition. This can augment torque when engine speed is high (The maximum engine power augments).
Intake Manifold Tuning Valve Operating Condition
ECM opens the intake manifold tuning valve when all of the following conditions are satisfied.
- Engine speed: 5, 050 RPM or more
- Engine coolant temperature: -30°C (-22°F) or more
- Battery voltage: 10 - 16 V or less