Inductive Ignition

APPLICATION INFORMATION

1. Each ignition module MUST be mounted onto an aluminium heat sink. Minimum
   dimensions:

   Thickness: 6mm.

   Area: Single channel module 70 sq cm
   Multiple channel module 100 sq cm

2. Apply heat conductive paste to mounting face prior to installation.
3. Module ground connection should be short, and connected directly to the chassis. Add a
   thin braided lead interconnect between the chassis in the vicinity of the module, and the
   engine block.
4. Simultaneous operation of the outputs of a multi channel ignition module can result in
   module failure due to current or thermal overload, and should be avoided. Therefore, twin
   plug distributor or direct fire ignition, or rotary engine ignition require at least two ignition
   modules.
5. ECU dwell time calibration MUST be set correctly for the application. Too little dwell will
   cause engine misfire. If set too large, module and/or coil damage will result. The most
   common symptom of excessive dwell is severe overheating of the ignition module that is
   the result of output stage saturation loss.
6. Correct dwell time calibration will typically cause coil and module temperature rises above
   ambient of less than 20 deg C at low RPM and less than 30 deg C at high RPM.
   
   Dwell calibration is easily determined using an oscilloscope. Primary circuit voltage
   should be monitored, and dwell time must be set below the value that causes the ignition
   module output stage to come out of saturation. A 0.1n or preferably 0.05n resistor can be
   inserted in series with the module’s ground connection in order to monitor the primary
   circuit current.
   
   Dwell time should be set to achieve the lesser of the module and coil current ratings.
   BOSCH modules available from AUTRONIC have a maximum current rating of 10A. If
   current ratings are unknown, adjust dwell to a value that avoids coil magnetic circuit
   saturation, loss of output stage saturation and excessive component heating. Peak
   current in the range 4A to 8A is usually required. Since dwell time requirement is supply
   voltage dependent, calibration must be determined for the full operating voltage range.