Mdec - Functions - MTU 12 V 2000 P12 Operating Instructions Manual

2.5 MDEC – Functions
Control functions
Following engine functions are controlled:
• Engine start
• Engine stop
• Emergency start
• Restart response
• Sequences with activated "Override" function (safety system bypass).
• Nominal speed switching between two set values (optional operation as 50 Hz or 60 Hz genset).
• Injection quantity as a function of engine loading and speed.
Engine start
The starting sequence is controlled by the software integrated in the engine governor as follows.
1. Engine start
2. Start lockout time t>16 seconds.
• Starting terminated if start lockout time is t<16.
3. Start interlock.
• Start terminated if start interlock applied.
4. Emergency air-shutoff flaps open.
• Start terminated if emergency air-shutoff flaps closed.
.
5. Starter on.
6. Speed n>n1 (configurable) reached within t1 (configurable).
• Start terminated if speed is n<n1 within t1. Start speed is too low "Start speed low".
.
7. Start injection quantity
8. Speed n>300 reached within t2 (configurable).
• Start terminated if speed is n<300 within t2 (configurable). Start speed is too low "Run up speed
low".
9. Starter off.
10. Idling speed reached.
• Start terminated if idling speed not reached, "Idle speed low".
11. Engine running at idling speed.
Restart response
The response of the engine is determined by the following factors on receiving a start request when the
engine is running down following a stop command:
• The engine immediately runs up to nominal speed if the engine speed is > 80 rpm;
• the engine is shut down if the engine speed is < 80 rpm. Restarting is only possible on expiry of the
start lockout time.
Emergency start
The following start interlock criteria are bypassed when override is active on starting the engine:
• Low coolant temperature (configurable).
• High coolant temperature (configurable).
• Coolant level (configurable).
Engine stop
An engine stop is tripped by activation of binary input BE1 at the engine governor or by the engine pro‐
tection system. Fuel is no longer injected as injector activation is disrupted.
Any starting procedure which has been initiated is interrupted.
28 | General Information | MS150025/02E 2012-10