Ask for help, the problem of ignition advance angle

When the engine (gasoline engine) works, the ignition time has a great influence on the working performance of the engine. Pre-ignition means that the spark plug ignites before the piston reaches the compression top dead center to ignite the combustible mixture in the combustion chamber. The angle of crankshaft rotation from ignition time to piston reaching compression top dead center is called ignition advance angle. The ignition advance angle that can make the engine get the best power, economy and emission is called the best ignition advance angle.

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The mixture in the cylinder burns at a certain speed, that is, it takes a certain time for the spark plug to ignite and the combustible mixture in the cylinder to burn completely. However, due to the high speed of the engine, the crankshaft can turn a great angle in such a short time. If the ignition happens just when the piston reaches the top dead center and the mixture begins to burn, then the piston has already started to move downward, resulting in a decrease in engine power. Therefore, it is necessary to ensure that the energy generated by combustible mixture can be effectively utilized by early ignition to improve the output power of the engine.

When the throttle opening, speed and mixture concentration of gasoline engine remain unchanged, the power and fuel consumption of gasoline engine change with the change of ignition advance angle. There is an optimal ignition advance angle for each working condition of the engine.

Proper ignition advance angle can make the engine do the most mechanical work in each cycle.

The ignition advance angle is too large, which is easy to deflagrate;

If the ignition advance angle is too small, the exhaust temperature will increase and the power will decrease.