Description & Operation

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2003 Nissan Xterra, 2003 Nissan Sentra, 2003 Nissan Pathfinder, 2003 Nissan Murano, and 2003 Nissan Maxima. However, it is still accessible from the selected car via links, so may be relevant.

This system has a swirl control valve in the intake passage of each cylinder. While idling and during low engine speed operation, the swirl control valve closes. Thus the velocity of the air in the intake passage increases, promoting the vaporization of the fuel and producing a swirl in the combustion chamber. Because of this operation, this system tends to increase the burning speed of the gas mixture, improve fuel consumption, and increase the stability in running conditions. Also, except when idling and during low engine coolant temperature, this system opens the swirl control valve. In this condition, this system tends to increase power by improving intake efficiency via reduction of intake flow resistance, intake flow. This swirl control valve is operated by the ECM.

Swirl control valve consists of actuator and valve. The valve is installed in the intake manifold, and the actuator is connected to the rear end of the valve shaft. The swirl control valve uses a step motor which has 4 winding phases. It operates according to the output pulse signal of the ECM. Two windings are turned ON and OFF in sequence. Each time an ON pulse is issued, the valve opens or closes. When no change in the pulse condition is needed, the ECM does not issue a pulse signal. A certain voltage signal is issued so that the valve remains at that particular position.

Swirl control valve position sensor is installed on the intake manifold. The sensor is connected to the front end of the swirl control valve shaft. The sensor responds to the movement of the valve shaft. This potentiometer type sensor transforms the position of the swirl control valve shaft into output voltage, and sends the voltage signal to the ECM.