HITACHI Electronic Ignition - DATSUN/NISSAN: Operation
Regardless of model, all distributors are equipped with a reluctor and stator, although the shapes may differ. The reluctor, which is mounted on the rotor shaft assembly, turns with the distributor shaft inside the stator.
As each reluctor tooth approaches and then passes the stator teeth, the magnetic field changes, creating an electrical signal in the pick-up coil. The pick-up coil is combined with the IC ignition unit on 200SX, 310, Pickup, Sentra, and Stanza models. This signal is received and processed by the IC ignition unit.
The IC ignition unit then turns on or cuts off current flow to the ignition coil primary circuit. When current to the primary is turned off, a high voltage surge is created in the secondary circuit, which fires the spark plug. Ignition timing is controlled by the relationship of the reluctor to the stator.
The IC ignition unit usually contains 4 or 5 circuits, which perform the following functions:
- Spark Timing Signal Monitoring Circuit - Monitors and amplifies signal from distributor pick-up coil.
- Lock-Preventing Circuit - Cuts off ignition coil primary current when ignition switch is "ON" and engine is not running.
- Duty Control Circuit - Controls the ratio of ignition coil primary current on-off time (equivalent to dwell angle).
- Power Switching Circuit - Makes or breaks the primary circuit current of ignition coil.
- Current Limiting Circuit - Not on all models. Controls the current valve so that excessive current will not flow through power switching circuit.
All circuits are contained in one IC ignition unit. Failure of any circuit requires replacement of entire IC ignition unit.
Diagram is for 4-cylinder systems with 8 spark plugs.
Diagram is for models with externally-mounted IC ignition units.