Operation of the variable ignition system (Opel Vectra A)

The variable ignition system has the ability to automatically adjust the system depending on driving conditions, the octane number of the fuel used, and the operating condition of the engine. The parameters used by such a system are: engine speed, temperature of the air entering the engine, engine load. In addition, the instantaneous engine load is taken into account. For example, if the speed is currently 4000 rpm, then it is determined in what situation these speeds occur: on a descent or on an ascent.



Necessary characteristics for system regulation (i.e. the optimal values used by the computer) are determined experimentally on a test bench and then refined during road tests of the vehicle. As a result, this gives the most favorable values for fuel consumption, exhaust gas composition and other engine characteristics in any operating mode.

If one or more sensors fail, the signals from which the computer uses to calculate the optimal engine characteristics, the engine power may decrease and fuel consumption may increase. There is no need to worry about serious engine damage, since in the event of such malfunctions the computer activates an emergency program and automatically sets a later ignition timing.



Computer operating modes (i.e. programs) can also be changed using a special connector. This is necessary if, for example, fuel with a different octane number is added.

In vehicles with a Motronic ignition system, the ignition distributor distributes the high voltage to the spark plugs via a rotor.

The rotor is driven directly by the camshaft. Centrifugal and vacuum ignition advance regulators are not needed here, since their functions are performed by the computer.