The ignition is controlled by a common electronic ignition and injection control unit. This occurs alternately through the two ignition coil units.
The change in the ignition moment is carried out in accordance with the characteristic stored in the memory of the control unit, and depends on the engine speed and its load. On engines since the middle of 1995, the characteristic ignition system with an inductive sensor, designated "EFZ-i". The control unit determines the position of the crankshaft from the flywheel sensor signal. Other factors that determine ignition timing are throttle position, coolant temperature, and intake air absolute pressure.
The flywheel has a special toothed rotor, the teeth of which are unevenly spaced. Two teeth are at a distance of 180 so that one of them determines the TDC, the other BDC of the sensor. Information about this is transmitted to the control unit.
The ignition coil on older engines or the ignition module on new ones can be disconnected as described in the previous section. The same applies to the ignition distributor of other engines.
The ignition system installed on most engines consists of the following parts:
1. Sensor installed in the flywheel housing.
The sensor informs the ignition module of the position of the flywheel at which a spark should be generated.
2. An electronic control unit that is simultaneously used to control the injection system.
3. ignition module.
4. Ignition coils or ignition distributor.
5. Ignition distributor.
6. The 16V engine has a position sensor mounted on the cylinder head. It is tuned to a specific intake camshaft cam and recognizes the TDC of the first cylinder (once per working cycle, i.e. for every two turns).
The ignition system determines the ignition timing in each cylinder in accordance with the data stored in the electronic memory. The memory receives data from individual sensors, namely from the flywheel sensor (engine speed and flywheel position), volume or mass meter of intake air (engine load), air temperature (the sensor is located in the volume or mass air meter) and coolant temperature. The throttle potentiometer provides throttle position information at start-up, idle, under load, and over idle. The ignition spark signal is supplied from the injection/ignition control unit to the ignition module, which controls the ignition. When carrying out any work on the cables or connections of the ignition system and the associated injection system, the ignition must always be switched off. For safety, you must also disconnect the battery if any cable is disconnected. This eliminates the possibility of a short circuit.
About the moment of ignition, its check, etc. cm. Ignition timing check.
It is necessary to say a few words about the knock control and the knock sensor available in the M1.5.4 injection system.
Combustion, accompanied by knocking in the engine and as a result of early ignition, is a danger to the engine in case of prolonged operation. It causes serious damage to the crankshaft bearings and pistons.
However, in modern cars, the maximum possible, earliest ignition is set. In order to correctly set the ignition timing during engine operation, which does not lead to detonation, various factors are taken into account. For this, knock control is used.
The combustion process in the cylinders is controlled by a so-called knock sensor, i.e. an electric sensor that detects sharp knocks appearing in the cylinder -"detonation". The sensor is screwed into the cylinder block. When uneven knocks appear in the cylinders, information about them is transmitted to the control unit, which processes it as follows:
1. As soon as the control unit receives a signal about the occurrence of detonation knocks during combustion, it determines in which cylinder the knocks appear. The ignition timing of the detected cylinder is shifted by 3 towards later ignition, in the remaining cylinders the ignition timing does not change.
2. If the engine continues to run with knocks, the control unit again shifts the ignition timing by 3 back. This may be repeated several times.
3. If knock-free operation of the cylinder is thus achieved, the ignition timing is adjusted to an earlier one after a while. But this time at 0.5. Further, during engine operation, for each stroke, the ignition timing is shifted by 0.5 towards earlier ignition until the previous ignition timing is reached again. In between, knocks may appear in other cylinders.
The diagram shown is a general knock control scheme. For Opel engines, the above adjustment angles have their own meanings.
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