Ignition System Function - GF07.10-P-1005MNF
Engine 176.9 in model 463
as of model year 2016 up to model year 2019
Function requirements for the ignition system, general points
- Circuit 87M (Engine management ON)
The circuit relay 87M(F58kN) is switched on for circuit 15 ON.
Ignition system, general points
Each cylinder is equipped with its own ignition coil. Here, there are two ignition coils independent of each other (ignition coil for cylinders 1 + 2 to ignition coil for cylinders 7 + 8 (T4 to T4/3)) each combined in a single coil case.
The ME-SFI [ME control unit (N3/10) reads in signals from the following sensors for the ignition system:
- Knock sensor 1 (A16/1)
- Knock sensor 2 (A16/2)
- Knock sensor 3 (A16/3)
- Knock sensor 4 (A16/4)
- Left intake camshaft Hall sensor (B6/4) and right intake camshaft Hall sensor (B6/5), intake camshaft positions
- Left exhaust camshaft Hall sensor (B6/6) and right exhaust camshaft Hall sensor (B6/7), exhaust camshaft positions
- Coolant temperature sensor (B11/4), coolant temperature
- Left charge air temperature sensor (B17/14) and right charge air temperature sensor (B17/15), charge air temperature
- Pressure sensor downstream of left throttle valve (B28/22) and pressure sensor downstream of right throttle valve (B28/23), engine load
- Crankshaft Hall sensor (B70), engine speed and crankshaft position
The requirements of the torque coordination function are also taken into account.
For the following partial functions, ignition angle adjustment in the direction "retarded" or "advanced" takes place:
- Idle speed control
- Inertia fuel shutoff
- Transmission overload protection
- Knock sensor system
- Torque coordination
Function sequence for ignition system
The ME-SFI control unit sends the signal for the ignition angle of the respective operating point to the ignition coil over the actuation line (circuit 4). The respective ignition coil interrupts the primary circuit after expiry of the dwell time. The ignition voltage (secondary electric circuit) passes from the ignition coil to the spark plug (R4) and causes arcing in the air gap between the center and ground electrodes.
Determination of the ignition angle takes place dependent on a characteristics map according to the input signals from the ME-SFI control unit.
Ideal development of the primary and secondary current for a multi-spark ignition
Engine configuration and ignition firing order
| Electrical function schematic for ignition system | PE07.10-P-2705-97ZGD | ||
| Overview of system components for gasoline injection and ignition system with direct injection | GF07.70-P-9998MNF |