Auto Ignition Coils

Auto ignition coils are transformer devices in automobile ignition systems which produce the high voltage necessary to fire the sparkplugs of gasoline internal combustion engines.

点火线圈是汽车点火系统中的变压器装置，用于产生点燃汽油内燃机火花塞所需的高压电能。

The primary winding of the ignition coil is wound with a small number of turns and has a small resistance. Applying the battery to this coil causes a sizable DC current to flow (Ohm's law) even though it has a significant inductance which slows the increase of that current to its maximum value. The secondary coil has a much larger number of turns and therefore acts as a step-up transformer. But instead of operating on AC voltages, this coil is designed to produce a large voltage spike when the current in the primary coil is interrupted. Since the induced secondary voltage is proportional to the rate of change of the magnetic field through it, opening a switch quickly in the primary circuit to drop the current to zero will generate a large voltage in the secondary coil according to Faraday's Law. The large voltage causes a spark across the gap of the sparkplug to ignite the fuel mixture.

点火线圈的初级线圈绕有少量的匝数，并具有较小的电阻。将电池接通到这个线圈时，尽管它有显著的电感，会减缓电流增加到最大值的过程，但仍会流过较大的直流电流（欧姆定律）。次级线圈绕有大量匝数，因此起到升压变压器的作用。但与交流电压不同，这个线圈设计用于在初级线圈电流中断时产生较大的电压尖峰。由于次级线圈中的感应电压与通过它的磁通量变化率成正比，快速在初级电路中断开开关以将电流降至零，将根据法拉第定律在次级线圈中产生较大的电压。这个高电压会使火花塞间隙产生火花，点燃燃料混合物。

The current in the primary coil is caused to drop to zero quickly be the opening of a fast transistor switch. This causes the magnetic field in the primary coil to drop rapidly, generating a large voltage in the secondary coil. The generated voltage is proportional to the rate of change of the magnetic field according to Faraday's Law, and the amount of change is multiplied by the effect of the iron core in the coil.

初级线圈中的电流因快速开断的快速晶体管开关而迅速降为零。这导致初级线圈中的磁场迅速下降，在次级线圈中产生较大的电压。根据法拉第定律，产生的电压与磁场变化率成正比，而变化量还受到线圈中铁芯效应的乘积影响。