System Description

SYSTEM DIAGRAM 

Courtesy of NISSAN

SYSTEM DESCRIPTION 

Ignition order: 1 - 3 - 4 - 2

The ignition timing is controlled by the ECM to maintain the best air-fuel ratio for every running condition of the engine. The ignition timing data is stored in the ECM. The ECM receives information such as the injection pulse width and camshaft position sensor signal. Computing this information, ignition signals are transmitted to the power transistor. During the following conditions, the ignition timing is revised by the ECM according to the other data stored in the ECM.

• At starting
• During warm-up
• At idle
• At low battery voltage
• During acceleration

The basic ignition timing is programmed within the anti-knocking zone, if recommended fuel is used under dry conditions. The knock sensor feedback control does not operate under normal driving conditions. If engine knocking occurs, the knock sensor monitors the condition. The signal is transmitted to the ECM. The ECM retards the ignition timing to eliminate the knocking condition.

BASIC CONTROL 

• When starting, ECM controls ignition timing according to the engine speed and coolant temperature.
• After the engine is started, ECM corrects the ignition timing according to the driving conditions (engine coolant temperature, accelerator pedal position, throttle position, control request from CVT etc.) based on the engine speed and fuel injection pulse width.
• If knocking occurs, ECM retards the ignition timing within the anti-knocking control zone according to the knocking condition.
• When the engine is idling, ECM controls the ignition timing to stabilize idling speed.
• ECM controls the duration of power transmission (power transistor ON time) to ignition coil according to the engine speed and battery voltage.
• When the engine idle speed or the ignition timing deviates from specified value, "Idle Air Volume Learning" is required.

CYLINDER DISTINCTION CONTROL 

ECM distinguishes cylinder based on the combination of signals of crankshaft position sensor, intake camshaft position sensor and exhaust camshaft position sensor, and if any of sensor malfunctions distinguishes cylinder with normal sensors.