Triple Induction Control System (TICS)

Triple Induction Control System:

The engine cylinder heads are designed with three valves per cylinder--two small intake and one large exhaust-- to improve torque and power by improving intake and exhaust efficiency at medium and high speeds. This arrangement has a weakening effect on the intake airflow at low speed because the intake valve area is too large and causes the intake air to slow as it enters the combustion chamber. The Triple Induction Control System prevents this by causing the intake airflow only through one intake valve at each cylinder and to enter the combustion chamber at high speed during low-speed operation.
During idle, light and medium loads, the engine control unit actuates the solenoid valve (TCIS) and manifold vacuum is applied to the swirl control valve actuator. The swirl control valves are opened slightly and most of the intake air is forced to flow through the small swirl ports. The air is fed directly to the swirl ports in the cylinder head where it is directed past one intake valve and into the cylinder. This causes a strong swirl in the combustion chamber and improves combustion for improved fuel economy.
During medium and high speed, heavy load conditions the solenoid valve (TCIS) is closed by the control unit and the vacuum is vented from the swirl control actuator. The swirl valves open and the intake air flows through the intake ports into the cylinder. At this time the effect of the improved three-valve arrangement is realized.
The computerized engine control related components in the VIRS are the airflow meter, the distributor, the solenoid valve, and the engine control unit (ECU).
The airflow meter measures the amount of airflow by connecting a potentiometer to a spring loaded sensor flap. The incoming air passes by the sensor flap, overiding the spring tension to a point of balance, and continues on into the engine. The potentiometer measures the amount of rotation of the sensor flap pivot and alters the reference voltage, thereby creating an input signal for the engine control unit.
The distributor is used as an input to the ECU for determining engine speed and crankshaft position. The Ne (Number of engine speed) signal is used for the engine speed input, and the G1 (Group 1) and G2 (Group 2) signals are used for the crankshaft position inputs. The sensors detect top dead center (TDC) at No. 1 cylinder and No. 4 cylinder.
The ECU receives the input signals from the sensors and determines the proper positioning of the TCIS solenoid valve. The solenoid valve is responsible for controlling the vacuum to the swirl control valve actuator.