Introduction to the MisGen3 system
Our misfire generators, used in development and testing of on-board misfire diagnostics in spark-ignited engines, consist of two electronic devices used together:
(1) A connection box that creates misfire through its interface to the vehicle’s ignition system; and
(2) A pendant containing user controls that determine the rate and pattern of misfires generated, i.e., which cylinders misfire and how often.
Because ignition systems vary greatly among different engine models and manufactures, two different versions of the misfire generator system are available to accommodate this diversity. While both systems include the same pendant, their connection boxes interact very differently with the ignition system to create misfire. The selection of one misfire system versus the other is dictated entirely by the following charateristic of the ignition system design:
a) Most modern engines with electronic ignition house the ignition coils separately from the electronics that control them. These engines require Global’s original MisGen3 system, in use since 1999.
b) Some newer automotive ignition systems incorporate the power electronics (i.e., the “coil driver”) into the same package as the ignition coil(s). These engines must use the new MisGen3 system for Integrated Coil Driver ignition.
It is imperative that the correct type of misfire generator be used on each ignition system. For more detail, read How to determine which misfire generator system my engine requires.
The user control pendant common to both misfire systems has the following features:
- The pendant includes two identical sets of controls for setting misfire pattern. This redundancy allows users to alternate between either of two misfire conditions (that they previously setup) during testing, thus minimizing driver distraction.
- In some cases, users may want to activate both patterns simultaneously, e.g., to intermittently disable two selected cylinders with differing misfire rates on each.
- Each set of controls allows three modes of misfire generation, including (1) periodic misfire, and (2) randomly misfired cylinders at fixed cycle intervals. While these modes accommodate regulatory testing, another mode of operation (3) extends misfire generation beyond the regulatory patterns.
- An external input allows remote activation of the selected misfire pattern via a 0-5V logic signal.
- The pendant contains a set of bi-color LEDs that flash (one per ignition coil) green or red depending on whether each spark was normal or defeated (misfired).
- The pendant’s internal logic associates repetitive sparks on multi-strike ignition with a single combustion event, thus maintaining the set misfire rate during single and multi-strike operation.
- Both versions of MisGen3 output user-accessible logic signals reporting each misfire created.
Although the connection boxes of both systems appear similar to each other in the following photos, they are not identical and do not contain the same circuitry.
MisGen3 with original Coil Connection Box | MisGen3 with new ICD Connection Box |
Our Misfire Generator meets all CARB requirements as outlined in the SAE J2901 requirements guidelines.
Videos on Misfire Generator: