Control, Starting And Stopping Sequences - MTU 12V4000L62FB Operating Instructions Manual

5.5 Control, starting and stopping sequences

NOTICE
Risk of engine damage due to incorrect action.
Risk of severe damage to property!
• Ensure engine is ready for operation before starting. See engine documentation.
Starting and stopping sequences
The start sequence is software-controlled and depends on the place of start command input.
To ensure that no mixture is in the engine when ignition is switched on or off, which is a specific requirement
for gas engines, special procedures for engine start / stop are specified.
The maximum number of starts is limited to three successive starts. Following these three starts, an extend-
ed purging phase is carried out with the gas shut-off valve closed and the ignition system switched off. Intake
system, engine cylinders and exhaust system (up to the outlet elbow of the exhaust turbine) are purged with
air. The plant-side part of the installation (gaseous fuel line up to gas dosing valve and exhaust system after
turbine) must be ventilated by appropriate systems or protected with shield gas. A 24V digital output is pro-
vided to activate such systems.
Start sequence
If a start command is activated with the engine being at standstill, the following steps are carried out auto-
matically:
1. Setting start counter
2. Prelubricating until the desired oil pressure is reached (optional)
3. Checking gas supply solenoid valves for leaks
4. Activating starter
5. Waiting for starting speed
6. Purging engine with air
7. Ignition
8. Opening gas supply solenoid valves
9. Waiting for starter disengagement speed
10. Stopping starter actuation
11. Waiting for idling speed
12. Runup to rated speed
Start termination
1. If a start was terminated, the maximum number of start is limited to three successive starts.
2. Following this, an alarm is output
3. External ventilation request via 24V digital output
4. Engine start is disabled as long as the fault is not acknowledged
Stop sequence
If a stop command is activated, the following steps are carried out automatically:
1. Gas supply solenoid valves close
2. Mixture throttles open, residual gas is purged with air
3. Engine coasts down to standstill or for a maximum coasting period
4. Deactivation of ignition
5. Mixture throttles close
52 | Operation | MS150098/03E 2018-04