HITACHI Electronic Ignition: Description

The Hitachi electronic ignition consists of a housing, rotor and distributor cap. See Fig 1. A reluctor, mounted on the shaft and governor assembly, combines with the pick-up coil to replace the conventional cam and breaker points.

With the ignition on, the distributor reluctor rotates past the pick-up coil. As each tooth of the reluctor approaches and passes the pick-up coil, a signal is sent to the ignition control unit. The control unit then turns the primary circuit in the ignition coil on and off as each tooth passes the pick-up coil.

This switching causes a build-up and collapse of a magnetic field in the coil, resulting in a high voltage surge in the coil's secondary circuit. This high voltage surge fires the spark plugs. See Fig 2.

Fig 1: Disassembled View of Hitachi Distributor

Courtesy of SUBARU OF AMERICA, INC.

Fig 2: Hitachi Electronic Ignition Circuit

Courtesy of SUBARU OF AMERICA, INC.