Swirl Control Valve (TICS)

Intake Air System:

Triple Induction Control System:

The swirl control valve, located in the intake manifold is part of what Mazda calls the "TRIPLE INDUCTION CONTROL SYSTEM" (TICS). Although the three valve arrangement in the cylinder heads (two intake valves and one exhaust valve per cylinder) greatly improves volumetric efficiency at medium and high engine speeds, low speed driveability and performance is reduced because of the low velocity and resultant poor atomization of the air/fuel mixture entering the cylinders.

To compensate for this effect, the swirl control valve closes most of the area of the main intake passages during low speed operation, forcing most of the intake air through smaller "swirl" ports, which open just behind one intake valve for each cylinder. Air flowing through the swirl port has much higher velocity as it enters the combustion chamber, which tends to fill the cylinder more efficiently with a better atomized air/fuel mixture. Since most of the air/fuel mixture is entering through only one intake valve, the mixture swirls around the cylinder, further atomizing the mixture and filling the cylinder more uniformly. As engine speed increases, the swirl control valve opens, allowing air to enter through both intake valves.

The vacuum signal to the swirl control valve actuator is regulated by a computer controlled solenoid valve. The solenoid gets power when the ignition is turned "ON" and energizes when the ECU completes the circuit to ground. The ECU monitors the throttle position sensor, and engine speed, and energizes the solenoid during idle, low speed/light load, and deceleration conditions. When the solenoid valve is energized, manifold vacuum is applied to the swirl control valve actuator to hold the swirl valves in the closed position. During moderate load/medium to high engine speed operation, the solenoid is de-energized. Manifold vacuum is blocked and the actuator diaphragm chamber is vented to the atmosphere, allowing the swirl control valves to open.