Gasoline injection and ignition system with direct injection, function - GF07.70-P-0002MRA
Engine 274.9 in model 205 (except 205.047/147/247), 253 (except 253.354/954)
Block diagram for networking the direct line
Block diagram for CAN-networking
Gasoline injection and ignition system with DI, general
The gasoline injection and ignition system with direct injection in electrical combination with the sensors and actuators of engine 274 (direct injection) forms the engine management system "MED40". The short designation "MED40" stands for:
M = Moronic
E = E
D = D irect injection
4 = 4-cylinder
0 =0
The whole engine management is contained in the ME-SFI [ME] control unit. Sensor data are directly read in from the engine management and indirectly via the CAN network and actuate the control actuators as required. Here the individual functions and systems of the engine management are controlled and coordinated by the ME-SFI [ME] control unit.
| Sales designation | Model | Motor | Transmission | Engine management | Notes |
|---|---|---|---|---|---|
| Model 205 | |||||
| C 180 sedan | 205.040 | 274.910 | 716.702, 722.995, 725.011 | MED40 | |
| C 200 sedan | 205.042 | 274.920 | 716.702, 722.995, 725.011 | MED40 | |
| C 200 4MATIC sedan | 205.043 | 274.920 | 722.968 | MED40 | |
| C 160 sedan | 205.044 | 274.910 | 716.702, 722.995, 725.011 | MED40 | |
| C 250 sedan | 205.045 | 274.920 | 716.702, 722.995, 725.011 | MED40 | |
| C 300 sedan | 205.048 | 274.920 | 722.994, 725.011 | MED40 | |
| C 300 4MATIC sedan | 205.049 | 274.920 | 722.969 | MED40 | |
| C 180 sedan (long wheelbase) | 205.140 | 274.910 | 722.995, 725.011 | MED40 | |
| C 200 sedan (long wheelbase) | 205.142 | 274.920 | 722.995, 725.011 | MED40 | |
| C 200 4MATIC sedan (long wheelbase) | 205.143 | 274.920 | 722.968 | MED40 | |
| C 260 sedan (long wheelbase) | 205.145 | 274.920 | 722.995, 725.011 | MED40 | |
| C 300 sedan (long wheelbase) | 205.148 | 274.920 | 722.994, 725.011 | MED40 | |
| C 180 wagon | 205.240 | 274.910 | 716.702, 722.995, 725.011 | MED40 | |
| C 200 wagon | 205.242 | 274.920 | 716.702, 722.995, 725.011 | MED40 | |
| C 200 4MATIC wagon | 205.243 | 274.920 | 722.968 | MED40 | |
| C 160 wagon | 205.244 | 274.910 | 716.702, 722.995, 725.011 | MED40 | |
| C 250 wagon | 205.245 | 274.920 | 716.702, 722.995, 725.011 | MED40 | |
| C 300 wagon | 205.248 | 274.920 | 722.994, 725.011 | MED40 | |
| Model 253 | |||||
| GLC 250 4MATIC Off-Roader | 253.946 | 274.920 | 716.755 | MED40 | |
| GLC 300 4MATIC Off-Roader | 253.949 | 274.920 | 716.755 | MED40 |
The engine management is subdivided into the following systems:
- Base functions
- Engine system
- Fuel injection system
- Ignition system
- Exhaust regulation
Base functions
- Control unit diagnosis
- Fault memory
- European On-Board Diagnosis (EOBD)
- Diagnosis via CAN
- CAN network
- Flash programming
- Transport mode
- Variant coding
- DAS stage 4 (FBS 4)
- Torque coordination
- Thermal management
- Alternator interface
- Maximum speed limit
Diagnosis
For diagnostic purposes, the fault codes of the engine management system can be read out and deleted using Xentry Diagnostics, and individual diagnostic functions can be specifically actuated.
CAN network
The ME-SFI [ME] control unit exchanges data with other control units that are integrated in the CAN network via the connected drive train CAN and engine CAN. The ME-SFI [ME] control unit also acts as the interface (gateway) between the two CAN bus systems. The ME-SFI [ME] control unit is also attached to the drive train sensor CAN (for CODE 920 (Gasoline direct injection with stratified charge)) and exchanges data over it.
Flash programming
The engine management in the ME-SFI [ME] control unit is flashable, that is the complete software in the control unit can be replaced using the Xentry diagnostics (replaced). The software required for control unit programming can be found on the diagnostic system software DVD.
Transport mode
In transport mode various functions of the engine management are limited. If the kilometer reading on the vehicle is more than 250 km, the system condition "vehicle transport mode" is automatically deactivated and can also not be reactivated any more by the Xentry Diagnostics.
Variant coding
With variant coding the following vehicle versions and equipment can, for example, be coded using XENTRY Diagnostics:
- Vehicle model
- National version
- Exhaust variants
- Transmission version
Engine system
- Starter relay actuation
- Throttle valve control
- Safety fuel shutoff
- Transmission overload protection
- Support for ESP®
- Fully integrated transmission control support
- Driving on torque limitation
- Suction fan actuation
- Throttle valve calibration
- Boost pressure control (over wastegate)
- Regulated adjustment of the intake and exhaust camshaft
- Controlling of the engine start/stop function
Fuel injection system
- Cylinder-selective DI
- Gasoline high pressure regulation
- Start, post-start phase and acceleration enrichment
- Warm-up control
- Idle speed control
- Limp-home function
- Rpm increase for an activated A/C
- Deceleration fuel shutoff
- Fuel pump controlling (low fuel pressure)
- Altitude adaptation (integral pressure sensor in ME-SFI [ME] control unit)
- Load change function
- Rpm limitation
Ignition system
- Multi-spark ignition
- Ignition map
- Rpm limitation
- Knock control
- Synchronization of camshaft and crankshaft position
Exhaust regulation
- Catalytic converter heating
- Exhaust gas recirculation (with NOx storage catalytic converter) (with CODE 920 (Gasoline direct injection with stratified charge))
- Purging of NOx storage catalytic converters (for CODE 920 (Gasoline direct injection with stratified charge))
- Oxygen sensor heater controlling
- Straight-line lambda control
Homogeneous mode (for engine 274 DI with homogeneous mode (DEH))
In homogeneous mode an homogeneous combustible fuel/air mixture (λ=1) is generated within the whole combustion chamber. There are no further measures required for exhaust aftertreatment since the normal three-way catalytic converter adequately converts the pollutants.
Stratified operation (for engine 274 DI with stratified charge (DES)) During stratified operation, a combustible mixture (λ≈1) is present only in the vicinity of the spark plug (R4) while various lambda values are present in the remaining combustion chamber. This varies from pure intake air through to exhaust gases from the EGR. Thus fuel consumption in stratified operation is less than that in homogeneous mode. Due to the excess air which consists of up to 75% by volume of nitrogen the NOx
development in stratified operation is significantly higher than in homogeneous mode. This requires use of a NOx
storage catalytic converter.
Homogeneous-layer-company (HOS)
The operating mode HOS delivers more favorable exhaust emission values in the range above 4 bar than pure stratified operation. At the same time it allows replacement of the homogeneous mode up to about 7 bar, whereby major consumption savings are achieved.
HOS is a combination of the homogeneous lean and classic stratified combustion system. Here for a de-throttled engine, the first injection is injected in the intake stroke; the actual "layer" injection takes place before ignition.
The following table presents the various different components on engine 274 for homogeneous mode (HID) and stratified operation (DIS):
| Components | M 274 DEG | M 274 DIS |
|---|---|---|
| EGR pressure sensor 1 (B5/5) (for CODE 920 (Gasoline direct injection with stratified charge)) | -- | X |
| EGR pressure sensor 2 (B5/6) (for CODE 920 (Gasoline direct injection with stratified charge)) | -- | X |
| Temperature sensor upstream of NOx storage catalytic converter (B16) (for CODE 920 (Gasoline direct injection with stratified charge)) | -- | X |
| NOx sensor control unit (N37/4) (for CODE (920) Gasoline direct injection with stratified charge)) NOx sensor (N37/4b1) (for CODE 920 (Gasoline direct injection with stratified charge)) | -- | X |
| Exhaust gas recirculation valve (Y27/1) (for CODE 920 (Gasoline direct injection with stratified charge)) | -- | X |
| Exhaust gas recirculation valve moving magnet (Y27/1y1) (for CODE 920 (Gasoline direct injection with stratified charge)) | -- | X |
| EGR line (for CODE 920 (Gasoline direct injection with stratified charge)) | -- | X |
| NOx storage catalytic converter (for CODE 920 (Gasoline direct injection with stratified charge)) | -- | X |
The operating conditions of the engine and the associated active partial functions of the engine management are described in the following documents:
| Crankcase ventilation system, function | GF01.20-P-0001MRA | ||
| Ignition ON, function | GF07.10-P-1000MRA | ||
| Starting, function | GF07.10-P-1001MRA | ||
| Ignition OFF, function | GF07.10-P-1002MRA | ||
| Fuel supply, function | GF07.10-P-1003MRA | ||
| Injection regulation, function | GF07.10-P-1004MRA | ||
| Ignition system function | GF07.10-P-1005MRA | ||
| Synchronize fuel injection and firing order function | GF07.10-P-1006MRA | ||
| Start, post-start phase and warm-up enrichment, function | GF07.10-P-1007MRA | ||
| Rpm control, function | GF07.10-P-1008MRA | ||
| Alternator interface function | GF07.10-P-1009MRA | ||
| Lambda control, function | GF07.10-P-1010MRA | ||
| Smooth running control, function | GF07.10-P-1011MRA | ||
| Thermal management, function | GF07.10-P-1012MRA | ||
| Torque coordination, function | GF07.10-P-1013MRA | ||
| Deceleration fuel shutoff, function | GF07.10-P-1014MRA | ||
| Knock control, function | GF07.10-P-1015MRA | ||
| Camshaft adjustment, function | GF07.10-P-1016MRA | ||
| Engine limp-home mode, function | GF07.10-P-1019MRA | ||
| On-board diagnosis, function | GF07.10-P-1020MRA | ||
| Engine timing start-stop function | GF07.10-P-1041MRA | ||
| Charging, function | GF09.00-P-2000MRA | ||
| Exhaust treatment function | GF14.00-P-3000MRA | ||
| Exhaust gas recirculation, function | Engine 274.9 in model 205 (except 205.047/147/247) with code 920 (Direct petrol injection with stratified charging) Engine 274.9 in model 253 (except 253.354/954) with code 920 (Direct petrol injection with stratified charging) |
GF14.20-P-3000MRA | |
| Electronic accelerator function | GF30.20-P-3015MRA | ||
| On-board refueling vapor recovery function | Engine 274.9 in model 205 (except 205.047/147/247), 253 (except 253.354/954) with code 494 (US version) |
GF47.10-P-3004MRA | |
| Purging function | GF47.30-P-3015MRA | ||
| Purging system with leak test function | Engine 274.9 in model 205 (except 205.047/147/247), 253 (except 253.354/954) with code 494 (US version) |
GF47.30-P-3016MRA | |
| Overview of system components for gasoline injection and ignition system with direct injection | GF07.70-P-9998MRA |