GF07.10-P-1001MTC | Starting, function | 10.5.12 |
ENGINES 270.9 in MODEL 242 with CODE (924) Monovalent natural gas drive
Starting function requirements, general points
Circuit 87M (engine control ON)
Engine OFF
Start enable for DAS Stage 3 (FBI 3)
Engaged gear range "P" or "N"
Outside temperature for natural gas operation above -15°C
Starting, general points
The ME-SFI [ME] control unit (N3/10) reads in all attached components from Circuit 15 onwards. If the data at this point in are plausible then they will be evaluated. The following sensors and signals are necessary for starting:
- Intake camshaft Hall sensor (B6/15), intake camshaft setting for ignition circuit detection
- Exhaust camshaft Hall sensor (B6/16), exhaust camshaft setting for ignition circuit detection
- Coolant temperature sensor (B11/4)
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- Crankshaft Hall sensor (B70) (with direction of rotation recognition), motor rpm
- Electronic ignition lock control unit (N73), "circuit 50 signal" via the chassis CAN (CAN E)
The ME-SFI [ME] control unit actuates the following components to start the engine:
- Starter (M1)
- Ignition coils (T1)
- Fuel injectors (Y76)
- The fuel system control unit (N118) directly and via the drive train CAN (CAN C) and thus the fuel pump (M3)
The ME-SFI [ME] control unit coordinates the injection and firing order during starting based on the signals from the crankshaft Hall sensor (with recognition of the direction of rotation) and the camshaft Hall sensors.
The starter control in the ME-SFI [ME] control unit takes on actuation and cutout of the starter.
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Function sequence for start
The starter control is subdivided into the following points:
Function sequence for start begin
Function sequence for start end
Function sequence for start begin
When ignition key (transmitter key (A8/1)) is moved to the start position, the ME-SFI [ME] control unit receives the "circuit 50 signal" from the electronic ignition lock control unit via the chassis CAN.
The ME-SFI [ME] control unit actuates the circuit 50 starter relay (F58kM) with a ground signal. The power contact on the starter relay closes and the starter solenoid switch is supplied at "circuit 50" with voltage from "circuit 30".
Function sequence for start end
Starter control is carried out automatically by the ME-SFI [ME] control unit (touch start). This means that once the start process is initiated, switching off "circuit 50" will have no further influence on the start procedure.
When engine cranking speed has reached 400 to 700 rpm, or after a starting time of 5 to 40 s (dependent on coolant temperature), the ME-SFI [ME] control unit interrupts the negative activation of the circuit 50 starter relay and thus terminates the starting procedure.
The starting procedure can only be aborted by switching off the ignition.