Ignition system — general information

As already mentioned, the ignition system works on a carbureted engine with an electronic control device or with an injection system. Only on carbureted engines without a catalyst, a conventional ignition distributor is installed, which regulates the ignition timing under the influence of centrifugal force and vacuum, which are switched on depending on the engine speed and load. When the engine speed increases, the centrifugal weights in the carburetor move outward under the influence of centrifugal force, against the force of a small return spring, while turning the adjusting cam relative to the distributor shaft, so that an earlier ignition is established. The vacuum device is connected to the carburetor by a small pipeline. At high vacuum, the ignition is set earlier, but is set back when the engine is under heavy load.

The ignition distributor is driven by one of the camshafts. On fuel-injected engines, ignition timing is electronically controlled to provide the best fuel/air ratio under all operating conditions. The ignition adjustment data is stored in the memory of the control unit. The control device receives information, such as injection duration and crankshaft position, and controls the key transistor at a given moment. The ignition timing is set to the optimum value when the engine is started, warmed up, idling, accelerating and coasting.