Idle Requests

Idle requests make the PCC run the genset at idle speed, instead of rated speed and voltage.

An idle request becomes active when all of these conditions are met:

· The PCC is in Manual mode.

· Genset Idle Enable is set to Enabled.

· Rated/Idle Switch (PCCnet) is set to Idle. (Rated/Idle Switch (PCCnet) is available in the Operator Panel.)

· There are no active shutdown faults.

· There are no active shutdown with cooldown faults.

If Genset Idle Enable is set to Disabled while an idle request is active, the idle request remains active. If any of the other conditions become untrue while an idle request is active, the idle request becomes inactive.

The PCC's response depends on the initial state of the genset and the final state of the genset.

6.7.1 Stop to Idle Speed

6.7.1.1 Prelube Engine

If Prelube Function Enable is Enabled, the PCC turns on the oil-priming pump. The PCC turns off the oil-priming pump when one of these conditions is met:

· Prelube Timeout Period expires.

· The oil pressure is greater than or equal to Prelube Oil Pressure Threshold.

6.7.1.2 Start Engine

If Starter Owner is set to GCS (Genset Control System), the PCC turns on the starter for up to two seconds.

If the engine speed remains zero, the PCC turns off the starter, waits two seconds, and turns on the starter again.

If the engine speed remains zero two consecutive times, the PCC generates shutdown fault 1438 (Fail To Crank).

If the engine speed becomes greater than zero, the starter follows these rules:

· If Cycle / Cont Crank Select is Continuous, the starter remains on for Continuous Crank Engage Time.

· If Cycle / Cont Crank Select is Cycle, the starter turns on for Cycle Crank Engage Time and turns off for Cycle Crank Rest Time. The starter repeats this process up to Crank Attempts times.

At the same time, the PCC checks these conditions:

· The engine speed is greater than Starter Disconnect Speed.

· The PCC's Backup Start Disconnect connection is active.

If any of these conditions are met, the PCC stops cranking the engine. This step is completed.

If none of these conditions are met, the PCC continues cranking the engine. If none of these conditions are met when the PCC finishes cranking, the PCC generates shutdown fault 359 (Fail To Start).

If Starter Owner is set to ECS (Engine Control System), the PCC does not control the starter but still checks the engine speed. If the engine speed is greater than Starter Disconnect Speed, this step is completed.

If the engine control module (ECM) or another device does not turn on the starter, the genset does not start, and there is no fault code. The PCC waits indefinitely for the engine to start.

NOTE: If LBNG Genset Enable is set to Enable and Enable Start-Enable Function is set to Enable, the PCC does not complete this step as long as warning fault 9973 (Start-Inhibit Warning Fault Event) is active.

6.7.2 Idle Speed to Stop

The PCC stops the genset.

6.7.3 Rated Speed to Idle Speed

This sequence begins when one of these additional conditions is met:

· Genset Application Type is set to Standalone or Synchronize Only.

· The open signal for the genset circuit breaker is active, and Genset CB Position Status is set to Open.

6.7.3.1 Rated to Idle Transition Delay

The PCC runs the engine at rated speed for Rated to Idle Transition Delay.

If Rated to Idle Transition Delay is greater than zero, event 1122 (Rated to Idle Delay) is active until the PCC finishes Idle Cooldown Time. (If this is an idle request, this event is active until the PCC finishes Idle Warmup.)

6.7.3.2 Stop Automatic Voltage Regulator (AVR)

The PCC stops driving the field windings in the exciter when the PCC stops running the engine at rated speed.

6.7.3.3 Rated to Idle Ramp Time

NOTE: If ECM CAN Enable is Enable, the ECM, not the PCC, actually controls the transition from rated speed to idle speed.

The PCC reduces the engine speed from rated speed to idle speed linearly during Rated to Idle Ramp Time.

6.7.4 Idle Speed to Rated Speed

The PCC waits until one of these conditions is met:

· The genset was running at rated speed and voltage before it started running at idle speed.

In other words, the PCC made a rated-speed-to-idle-speed transition to get to idle speed.

· The engine has been running at idle speed for Idle Warmup Time.

· The coolant temperature is already greater than Idle Warmup Coolant Temp.

· Manual Warmup Bypass is set to Bypass Warmup. (This parameter is not available in the Operator Panel.)

6.7.4.1 Idle to Rated Ramp Time

The PCC raises the engine speed from idle speed to rated speed linearly during Idle to Rated Ramp Time.

6.7.4.2 Start Automatic Voltage Regulator (AVR)

The automatic voltage regulator (AVR) is enabled when all of these conditions are met:

· AVR Enable is set to Enable. (This parameter is not available in the Operator Panel.)

· The PCC is in Auto mode; or the PCC is in Manual mode, and Excitation Disable Override is Excitation On.

If all of these conditions are met, the PCC starts driving the field windings in the exciter when the engine speed reaches Governor Enable Engine Speed. Then, it raises the voltage to rated voltage linearly during Voltage Ramp Time.

If any of these conditions is not met, the PCC does not drive the field windings in the exciter.

6.7.5 Additional Steps for Hydromechanical Engines

6.7.5.1 Glow Plugs

The PCC controls the glow plugs if the following conditions are met:

· Engine Application Type is Hydro-Mechanical.

· Glow Plug Enable is Enable.

· Fuel System is Diesel.

If the PCC controls the glow plugs, it turns on the glow plugs each time before it turns on the starter. The PCC turns on the glow plugs for an amount of time that depends on the current coolant temperature.

· If the coolant temperature is less than Min Preheat Temperature, the PCC turns on the glow plugs for Min Time at Preheat Temperature.

· If the coolant temperature is between Min Preheat Temperature and Max Preheat Temperature, the amount of time decreases linearly as the coolant temperature approaches Max Preheat Temperature. For example, if the coolant temperature is halfway between Min Preheat Temperature and Max Preheat Temperature, the amount of time is one-half Min Time at Preheat Temperature.

· If the coolant temperature is greater than Max Preheat Temperature, the PCC does not turn on the glow plugs at all.

The PCC does not turn on the starter until it turns off the glow plugs.

NOTE: If the PCC controls the glow plugs, it takes longer to start the engine because the PCC turns the glow plugs on and off each time before it turns on the starter.

If the coolant temperature is less than Max Post Glow Temperature, the PCC also turns on the glow plugs for Max Post Glow Time after the engine has started. This can help the engine start more smoothly, and it might reduce the amount of white smoke during startup.

Each time it runs the start sequence, the PCC stops turning on the glow plugs once the glow plugs have been on for Max Preheat Glow Time.

6.7.5.2 Crank Fueling

No. Description No. Description

F Rate of fueling r1 Crank Fueling Ramp Rate

F1 Initial Crank Fuel Duty Cycle t Time

F2 Max Crank Fuel Duty Cycle t1 Initial Crank Fueling Period FIGURE 67. CRANK FUELING

During cranking, the AUX 105 controls the rate of fueling as follows:

1. The rate of fueling is Initial Crank Fuel Duty Cycle for Initial Crank Fueling Period.

2. The rate of fueling rises from Initial Crank Fuel Duty Cycle to Max Crank Fuel Duty Cycle at Crank Fueling Ramp Rate.

3. The rate of fueling remains at Max Crank Fuel Duty Cycle.

After cranking, the rate of fueling is Crank Exit Fuel Duty Cycle until the electronic governor takes control of the rate of fueling.

6.7.5.3 Start Electronic Governor

The electronic governor is enabled when all of these conditions are met:

· Engine Application Type is Hydro-Mechanical.

· Electronic Governor Enable is Enable.

If all of these conditions are met, the PCC starts the electronic governor when one of these conditions is met.

· The engine speed reaches Governor Enable Engine Speed.

· The engine speed reaches Idle Speed, and the engine is going to warm up in idle.

Then, the electronic governor raises the engine speed to idle speed (if the engine is going to warm up in idle) or rated speed linearly during Governor Ramp Time.