Stick Coil

The stick coil’s cylindrical ignition coil generates a high voltage to the spark plug. Based on a signal from the engine ECU, a driving circuit (igniter) drives the ignition coil. Because the cylindrical ignition coil is designed to be stored in the engine plug hole, DENSO’s stick coil is easy to install in the engine.

DENSO Technology – Leading the World
In 1996, DENSO developed the world’s first stick coil that employed a cylindrical ignition coil.


Benefits and Features

  • Small size, light weight, and smooth appearance on the top of the engine head cover

    • The cylindrical coil can be installed in the plug hole, which was previously a “dead space”.
    • A newly developed small-size driving circuit has been integrated into the top of the plug.
  • Energy saving

    • Improving the coil’s magnetic efficiency reduces the time needed to generate high voltage for the ignition coil.

Basic Structure

Technology Evolution

This ignition unit consisted of an ignition coil and a distributor that delivered the voltage generated by the ignition coil to the ignition plugs. Following this product, mechanical power distribution evolved into electronically distributed power.


In Japan, the IIA (Integrated Ignition Assembly) first integrated the distributor, the ignition coil and the driving circuit (igniter). Eliminating the high-voltage cable between the ignition coil and the distributor improved reliability.


DLI (Distributor-Less Ignition): High voltage generated by the ignition coil was directly applied to the respective ignition plug. The distributor was eliminated, resulting in significantly reduced weight. Higher reliability was achieved by electrically controlling high-voltage distribution and ignition timing.


Stick Coil
DENSO commercially developed the world’s first cylindrical ignition coil that can be installed in the engine plug hole. This coil and a small igniter improved the appearance of the engine head cover.