Starting ignition timing

/ 9-5 (9600) / 1998 / 2. Engine / Trionic, 4-cyl / Technical description / Starting ignition timing

From the time the engine is stationary until it reaches the requested idling speed, starting ignition timing is active.

The ignition timing is normally set at 10° BTDC, but is retarded when intake air temperature exceeds 4 °C. When the temperature of the intake air reaches 100 °C, the ignition advance is 3° BTDC. The reason for retarding the ignition when the air temperature rises is because the speed of combustion also increases.

In connection with starting, the control module triggers the relevant cylinder with 200 Hz for 60 crankshaft degrees, whereupon "multisparks" occur. When engine speed exceeds 450 rpm, the frequency is increased to 330 Hz. The function is stopped when engine speed exceeds 650 rpm. If engine speed falls below 450 rpm again, the function is re-activated.

The aim is to ensure ignition under unfavourable starting conditions and to prevent the engine dying after starting.

Starting ignition timing

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