Ignition, Basic Function

1 Idling speed Ignition timing
With idle speed control active, the timing is adjusted to stabilize the idling speed. The value is sent to box 3.







2 Normal Ignition timing
When idle speed control is inactive, the ignition timing is read from a load and engine speed dependent matrix The value from the matrix is optimized for the lowest fuel consumption (best engine torque). The value is sent to box 3.

3 Selection of ignition timing
One of the ignition timing calculations is selected depending on which function is active. The value is sent to box 6.

4 Compensation







The ignition timing is corrected depending on the engine coolant temperature and intake air temperature. The value is sent to box 6.

5 Knock control
It knocking occurs, a timing retardation will be calculated. The value is sent to box 6.

6 Total
The compensation angle and knock retardation are totalled to give the current ignition timing. The value is sent to box 7.

Selection of Ignition timing
Starting ignition timing is selected when the engine has not yet been started. The value is sent to box 9.







Starting ignition timing
The starting ignition timing is calculated depending on the intake air temperature and the coolant temperature. The value is sent to box 9 via box 7.

Activate relevant trigger
At the calculated crankshaft angle, the microprocessor controls the transistor for the trigger that is next in the firing order.