• Main Engine Electronic Governor System (AI EGS 2000)

    Main Features

    • Engine torque pre-warning and limits
    • Scavenging air pressure pre-warning and limits
    • Smart tacho feedback system
    • Engine Start/Stop option
    • Actuator drive with brake monitoring and control
    • Multiple operating performance modes
    • 7” touch colour graphic operator interface
    • Supports shutdown from safety system
    • Supports slowdown from alarm monitoring system
    • Critical speed avoidance
  • Overview

    The basic task of the AI EGS 2000 is to regulate the shaft speed of the engine. AI EGS 2000 is a fully automatic main engine electronic governor system. It consists mainly of:

    1. Governor controller unit

      Located in the ECR. It contains all the modules for command and feedbacks and also controls the operation of the actuator drive unit.

    2. Actuator drive unit

      Located in the ECR. It controls the actautor motor located at the engine to exerts a force on the fuel rod to adjust the fuel index.

    3. Tacho signal analyser

      Located in the ECR. It detects the signals from the two pickup sensors located at the engine turning wheel and converts the signal for the Governor controller to get the speed of the engine output shaft.

    4. Operator interface unit (AI3070TN)

      Located on the ECR console. It is touch screen operator graphic interface that is used to monitor vital engine parameters regarding the governer system and to configure the system setting and operating setpoints.

  • Block diagram of AI EGS 2000

  • Operator Interface Unit

    The Operator interface unit AI3070TN is located near the maneuvering lever on the ECR console. It displays a number of parameters used by the governor system.

    1. SCAV Air Press (Bar)

      It gauges the scavenging air pressure in Bar in a circular dial format thats easy to read at a glance.

    2. Mode

      It is used to manually select one of the three operating modes. They are usually selected based on weather conditions or for specific engine performance testing.

    3. Current Index & Demand Index

      It displays the fuel index position and the demand to the actuator drive unit in a bargraph format.

    4. Set Maximum Index

      It is used to manually set the limit for the maximum index allowed during engine operation.

    5. M/E Operation Status

      It displays the engine operation stage which helps the operator infer the current control behavior of the the AIEGS 2000.

    6. Alarm Summary

      It displays all the alarms and system messages of the AIEGS 2000 along with date and time of occurance and alarm status.

    7. RPM

      It displays the RPM command set point from the maneuvering lever and the engine shaft speed feedback in a bargraph format.

  • Operator interface unit (AI3070TN)

    deviation from either the torque curve or scavenging air pressure curve is above set limit) and the status of the Start/Stop valves. It also gives the option to cancel all limits during operation (supervised action requiring passcode).

  • Maneuvering lever and operator interface unit (AI3070TN) on the ECR console

  • Overspeed Protection Smart Tacho Feedback System

    The speed of the engine is measured by a tacho system using two independent pickups, TACHO 1 and TACHO 2. The signals from the pickups are then sent to the Tacho signal analyser and forwarded to the Governor controller.

    AIEGS 2000 will monitor both RPM feedbacks and check if they are within a valid range and then select the highest of the two to use for system calculations. If a malfunction of a pickup signal occurs it will automatically disregard that signal followed by a tacho failure warning alarm and use the other pickup signal for system calculations. In almost all cases a failed pickup will cause the signal to go to zero, hence the system will automatically use the signal from the other tacho. In very few cases, a failed tacho will give increased speed signal. In such a case, AIEGS 2000 will regulate according to the apparant increased speed and reduce the actual speed of the engine with a tacho failure warning alarm. Also in the very rare case of both tacho pickups failing to zero signal, AIEGS 2000 will stop regulating RPM and fix the fuel to start index position and after a reasonable period failing to detect a feedback it will notify a prediction error warning alarm followed by a prediction error shutdown alarm which will cause the AIEGS 2000 to initiate shutdown sequence.

    This certifies that a failure in the tacho system will never give rise to an overspeed situation.

  • Multiple Operating Modes Increased Efficiency

    AIEGS 2000 allows the operator to select either three of the operating modes displayed on the operator interface unit AI3070TN. The mode to be used is selected based on prewailing weather conditions.

    1. RPM MODE

      This mode is usually used in calm sea weather conditons. AIEGS 2000 will maintain constant RPM as per the set point from the maneuvering lever.

    2. POWER MODE

      This mode is selected during moderate to rough weather conditions. AIEGS 2000 will maintain constant shaft power with a wider RPM regulation band to reduce wear and tear of the fuel rack and actuator motor.

    3. INDEX MODE

      This mode is generally used when measuring engine performance tests. It will maintain constant command on the basis of the predefined torque curve

  • Performance Monitoring And Control Engine Torque And Scavenche Air Pressure Pre-Warning And Limits

    AIEGS 2000 has a function to monitor the torque curve and scavenging air pressure curve. During operation it takes various references from these curves to set the fuel index. The primary aim of refering these curves is to avoid poor combustion of fuel due to higher than required fuel index or low scavenging air pressure.

    During the operation of the engine, if the any of these parameters deviates from the defined curves, a pre-warning alarm will be notified to alert the operator. If the parameter contiues to deviate further and exceeds the limit curve, AIEGS 2000 will indicate Regulation limited on the Operator interface unit and regulate the fuel index to normalize the irregular parameter. Henceforth the RPM regulation will be limited until the operator resets this alarm.

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