Rotax engines with Nippon Denso
CDI Ignition

CAPACITOR DISCHARGE IGNITION SYSTEM

1. INTRODUCTION

The NIPPONDENSO Capacitor Discharge Ignition (C.D.I.) System consists of a flywheel generator, a control unit and an ignition coil. The flywheel generator which is outer rotor type with 4-pole permanent magnets, supplies two ignition signals per revolution and electric energy into the control unit. The stator of flywheel generator embodies two capacitor-charging coils and a lighting coil.
The control unit incorporates a storage capacitor, a switching circuit, a S.C.R. (Silicon Controlled Rectifier) and rectifiers. The rectifier D₁ is connected in parallel with the primary winding of ignition coil to extend the spark arc duration time. Each element in the control unit is molded in the case with resin.
Therefore the control unit is superior for vibration-resistance and water-proofness.
The molded ignition coil is a kind of transformer which boosts the primary voltage and induces the higher voltage in the secondary winding to simultaneously make sparks at both spark plug gaps.