Funkčnosť a princíp jednotlivých dielov na DOLMAR /podobne to musia mať aj iný výrobcovia/ nájdete tu - Training material. Treba stiahnuť súbory a nainštalovať na Windows a môžete sa začať hrať. Strašne veľa vecí Vám týmto dôjde. Ako inak by súčasné modely mohli nekopnúť pri štarte a pritom naštartovať po "jemnom" prekonaní kompresie./ Keď ma napr. kopla pri štarte STIHL 039 tak som sa ju bál chvíľu naštartovať a palce ma boleli dosť dlhú chvíľu/. Pritom majú výkon napr. 50 ccm 2,9 kW. Z toho pramení aj trocha vyššia poruchovosť /napr. v zapalovaní je mikroprocesor/ Týmto potom veľa "pseudoodborníkov" uzemníte a vytvoríte si vlastný názor na vec.
Description of the digital ignition system
1. Structure and operating principle
The ignition system consists of the ignition module, magnet wheel, stop wire, high voltage wire, spark plug cap, STOP switch and spark plug.
The magnet wheel is affixed to the crankshaft and rotates with it at engine speed. The rotation causes the magnet group in the magnet wheel to rotate past the ignition yoke once per turn. The resulting change in the magnetic flow in the yoke generates a voltage in the ignition charging coil. This induced voltage charges a capacitor, which serves as an energy storage device.
To generate a spark, the capacitor is discharged at a specific time. The voltage from the discharging process is transformed to high voltage via the primary and secondary coil using the transformer principle. Once a specific voltage level is present in the spark plug, it discharges a spark. The voltage required to trigger spark discharge in the spark plug depends to a large degree on the electrode gap. The smaller this gap, the lower the voltage required to trigger sparking, but also the weaker the spark. Therefore, the specified electrode gap should always be maintained.
When the stop switch is actuated, the entire voltage of the capacitor is discharged to ground, so that no further sparking can occur at the spark plug.
1.2. Special features of the digital ignition system
On the digital ignition system, the time of capacity discharge (and thus also sparking) is controlled by a microcontroller, via software in the microcontroller. By changing the software parameters, it is possible to change the spark timing whenever desired, unlike with an analog ignition system. Furthermore, multiple ignition curves or peaks in the ignition curve can be programmed. Thus, the spark timing can be adjusted to suit the operating conditions of the engine.
2. Functioning
The ignition system is responsible for igniting the fuel-air mixture in the cylinder. On a two-stroke engine, mixture ignition takes place once per turn. As engine speed increases, there is less and less time available for full combustion of the mixture. For this reason, as engine speed increases the ignition spark must come earlier and earlier in the cycle (towards bottom dead center).
In idle, the ignition timing is set to be very late (towards top dead center), in order to make the engine speed easier to set and so that it runs more smoothly.
If the engine is accelerated out of the idle range, ignition gets earlier, and gets earlier as speed increases. In each case, ignition is timed to achieve optimum performance in the given speed range.
At the governor limit, the ignition timing is moved to late, in order to keep from overtaxing the engine. If the engine speed rises beyond that point, the ignition system switches off and there is no more spark, thereby limiting the maximum engine speed. Once the engine speed falls below the governor limit, the ignition system switches back on. Jaro Š
