What does a high tension coil in an ignition system do?

A high tension coil, commonly referred to as an ignition coil, plays a crucial role in the ignition system of an internal combustion engine. Its primary function is to store electrical energy and convert it into a high voltage that is necessary to create a spark at the spark plug. When the ignition system is activated, the coil takes a low-voltage electrical signal from the battery or ignition system and transforms it into a much higher voltage, often in the range of thousands of volts. This high voltage is essential for overcoming the gap between the spark plug electrodes, ensuring that the air-fuel mixture in the engine cylinder ignites properly. Without the high tension coil performing this function, the spark plugs would not generate the necessary spark, potentially leading to engine misfires or failure to start.

The other options relate to functions that are not within the scope of the ignition coil's role. Increasing fuel pressure pertains to the fuel delivery system, measuring current flow is typically done by electrical sensors or ammeters, and regulating airflow is handled by components such as the throttle body or air intake systems. Hence, the ignition coil's primary function is correctly identified as storing electrical energy for ignition, making this choice the accurate answer.