BUSHING 5K4273 - Caterpillar

The components of the gas engine ignition group and the fully shielded ignition system wiring are used with the magneto in order to provide spark ignition.Ignition Transformer
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Components Of The Gas Engine Ignition Group (1) High energy ignition transformer. (2) Tube. (3) Extension with a spring loaded rod. (4) Spark plug.The ignition transformer causes an increase of the primary voltage. The increased voltage is needed to send a spark (secondary electrical impulse) across the electrodes of the spark plugs. For good operation, the connections (terminals) must be clean and tight. The negative transformer terminals for each transformer are connected together and the terminals are connected to ground.Timing Control System
The Caterpillar Detonation Sensitive Timing Control (DSTC) system provides detonation protection for the engine and electronic adjustment of ignition timing with a variable timing. This ignition system consists of four basic groups (Timing Control Module, Magneto Interface Box, Variable Timing Magneto, and Sensors).
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Timing Control SystemTiming Control Module (TCM)
The TCM determines the ignition timing. The TCM communicates the ignition timing with the Magneto Interface Box (MIB). The TCM provides the system diagnostics.Engine timing, controlled by the TCM, is based upon the desired timing signal received from the ECM. The desired timing signal from the ECM varies depending on engine speed, engine load and engine detonation.The ignition timing is controlled by three signals that are sent from the TCM to the MIB. The MIB sends a signal that indicates that the plug is firing to the TCM. The TCM uses this signal to calculate actual engine timing.Magneto Interface Box (MIB)
The MIB receives three signals from the TCM. These signals define how much the timing should be retarded in order to provide the desired engine timing. The MIB then closes the connection between pins "A" and "F" or "E" and "F", going to the magneto. This occurs when the magneto is sending primary voltage of 170 to 200 VDC in order to fire the spark plugs.In order to identify the timing of the primary ignition pulses, the magneto capacitor voltage signals are also sent to the MIB. The primary ignition pulses are when the spark plugs fire. The MIB converts the odd bank capacitor voltage into a lower voltage ignition pulse signal that is sent to the TCM. When operating in Magneto Calibration Mode, the connections between "A" and "B" or "E" and "F" in the MIB are continuously made.Variable Timing Magneto
Standard magnetos discharge the ignition capacitor to the ignition coil. This occurs as soon as the rotor enters the magnetic field of a stationary pole. For the variable timing magnetos, the ignition capacitor will discharge while the rotor is within the magnetic field of the stationary pole. The ignition timing window is defined as the timing when the rotor enters the magnetic field to the timing when the rotor exits the magnetic field. For variable timing magnetos, the capacitor will discharge only when the rotor is within the timing window and an external switch, provided by the