For petrol engines with electronic ignition, the control unit determines the ignition timing based on the ignition characteristic stored in its memory. Synchronization of the ignition system is carried out by signals that enter the control unit from the Hall sensor or pulse sensor. The presence of anti-knock control ensures the efficiency of engine operation at a high compression ratio and compensation for differences in fuel quality characteristics. The knock sensor on the cylinder block detects the occurrence of knocking during the combustion of fuel and initiates the engine control unit to shift the ignition in the direction «late». This ensures that the engine runs smoothly and is not damaged by detonation. Some engines have two knock sensors on the cylinder block.
Ignition coil/spark plug. Engine 2.0 l ALT
- 1 - Screw
- 2 - Plug strip
- 3 - Connecting plug
- 4 - Ignition coil with output stage
- 5 - Spark plug, 30nm
- 6 - Connecting plug
- 7 - Bolt, 10nm
- 8 - Hall sensor
- 9 - Bolt, 25Nm
- 10 - Washer, conical
- 11 - Hall sensor cover. When installing, pay attention to the fixation.
- 12 - Knock sensor 1
- 13 - Knock sensor 2
- 14 - Screw, 20Nm. Observe the exact tightening torque as this affects the operation of the knock sensor.
- 15 - Three-pin green knock sensor connector 1. Mounted on the front wall of the engine compartment on the left in the direction of travel, under the expansion tank
- 16 - Three-pin green knock sensor connector 2. Mounted on the front wall of the engine compartment on the left in the direction of travel, under the expansion tank
Direct ignition
The distribution of the ignition current over the candles is controlled by the electronic control unit.
Petrol engines 1.6 and 2.4 l have 2 or 3 ignition coils located in the same housing with the output stage on the cylinder head. Each ignition coil supplies voltage to 2 spark plugs. Some engines have 4, 6 or 8 ignition coils located directly on the spark plugs. In this case, the ignition cable is missing.
There is no external adjustment of the ignition timing. If the ignition timing deviates from the specified value, it is necessary to replace the damaged elements.
The ignition system does not wear out and does not require maintenance. The maintenance schedule only requires replacement of the spark plugs.
Basic information on the operation and sensors of control and injection systems is described in Section Functioning of the control system and injection of a gasoline engine.
Safety measures when working with the ignition and injection system
To avoid personal injury and/or damage to the ignition injection system, the following must be observed:
- Do not touch or disconnect the ignition wires while the engine is running or the starter is engaged.
- Disconnect and connect the pipelines of the injection system and the ignition wires, as well as the electrical wires of the measuring instruments only with the ignition off.
- Do not allow people with a pacemaker to operate the electronic ignition system.
- Do not ground terminal 1 of the ignition coils.
- When cranking the engine with the starter, for example, when checking the compression pressure, turn off the ignition and disconnect the crankshaft position sensor connector.
- Do not connect a test lamp to terminal 1 of the ignition coils.
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