STUD 9H1022 - Caterpillar

The engine is equipped with an electronic ignition system. The system provides dependable firing and low maintenance. The system provides precise control of the spark and of the ignition timing for each cylinder.Each cylinder has an ignition transformer. The ECM controls ignition on the left bank and on the right bank. To initiate combustion, the ECM sends a pulse of approximately 100 V to the primary coil of each ignition transformer. The pulse is sent at the appropriate time and for the appropriate duration. The transformers step up the voltage to create a spark across the spark plug electrode.Detonation sensors monitor the engine for detonation. Each sensor monitors two adjacent cylinders. The sensors generate data on vibration that is processed by the ISM to determine detonation levels. The ISM monitors detonation from 0-30 deg ATDC for each cylinder.If detonation occurs, the ECM retards the ignition timing of the affected cylinder or cylinders up to 6 degrees. If a cylinder has been fully retarded for 16 combustion cycles and the cylinder is still detonating, the ECM shuts down the engine. During a detonation shutdown request, the ECM retards the detonating cylinder an additional 6 degrees, not to exceed 10 degrees total.The ECM provides diagnostics for the ignition system.A detonation event issued for one of the two cylinders being monitored by a single sensor is most likely a problem with the individual cylinders fuel or ignition system. A failed detonation sensor will produce a false signal which the ECM generates an event for both cylinders being monitored.Refer to the engine Troubleshooting manual for more information on the diagnostics of the ignition system.Ignition Transformers and Spark Plugs
Illustration 1 g06146836
Ignition transformer and spark plug
(1) Ground spring
(2) Primary connection
(3) Secondary connection
(4) Extension
(5) O-ring seal
(6) Spark plugEach transformer is grounded to a valve cover via ground spring (1). The ignition harness is connected to primary connection (2) which receives the pulse of approximately 100 volts. The output from the secondary circuit of the transformer is sent to the spark plug through secondary connection (3). The transformer secondary circuit provides an initial 8,000 V to 32,000 V to the spark plug to create a spark. The spark ignites the air/fuel mixture in the cylinder.Generator set applications use a spark plug with a precombustion chamber.Industrial applications use the standard style of spark plug.