Models with EZL ignition system
The main elements of the ignition system type EZL are spark plugs (one for each cylinder), high-voltage wires, distributor, electronic ignition coil and electronic control unit (ECU) together with the corresponding sensors, actuators and wires. Depending on the model, the arrangement of the elements may vary, but their basic functions are the same.
The basic function of the ignition system is as follows. The control unit supplies the supply voltage to the primary winding of the ignition coil. The supply voltage is periodically interrupted by the ECU and this is manifested by the disappearance of the magnetic field, which then induces an even higher voltage, called high voltage, in the secondary winding of the coil. This high voltage is supplied by the distributor via high-voltage wires to the spark plugs in the cylinders directly at the required moment. The electrodes of the spark plug have a gap small enough for a spark to occur between them and the spark that jumps ignites the fuel-air mixture in the cylinder. The ignition timing is critical and is therefore regulated exclusively by the ECU.
The ECU determines and controls the ignition timing and, first of all, the angle of the closed state of the contacts, in accordance with information about engine speed, crankshaft position and the degree of vacuum in the intake manifold, received from sensors mounted on the engine, other parameters that determine the ignition timing are the position of the throttle valve (idle speed and full throttle positions are determined using the gear shift lever), intake air temperature and coolant temperature. These parameters are also monitored by sensors located on the engine.
The main ignition timing can be changed to fixed positions to suit the type of fuel used. This is achieved by means of the compensator socket located in the engine compartment, next to the ignition ECU - refer to paragraph 6 for more information.
Models with TSZ ignition system
The overall operation of the system is similar to that described for the EZL system with the following differences.
Instead of determining the ignition timing by the position of the crankshaft sensor, the TSZ system is switched by a sensor located on the inside of the distributor housing. This arrangement allows the basic ignition timing position to be changed by rotating the distributor housing relative to the distributor shaft.
[Material created based on the website: MercedesMAN.ru]
The ignition timing is controlled electronically and, in part, by a vacuum unit mounted on the distributor housing. The electronic control unit provides timing advance as engine speed increases, and the vacuum unit adjusts the timing depending on engine load from a vacuum diaphragm on the carburetor/throttle body.
On carburetor models, the thermostat and shut-off valve provide additional advance using a vacuum unit when the engine warms up.