Common Rail Diesel Injection (CDI), Function - GF07.16-P-0001OLF
ENGINE 651.9 as of 6/1/15 in MODEL 166 as of model year 2016
Direct networking block diagram
Block diagram for CAN-networking
Common rail diesel injection system (CDI), general points
The Common Rail Diesel Injection (CDI) constitutes the engine management "CR43" in electrical connection with the sensors and actuators of engine 651
The short designation "CR" stands for:
CR = Common Rail
The "common rail" is the line shared by all injectors for fuel delivery.
The fuel upstream of the injection is stored in this common line.
The entire engine management system is located in the CDI control unit (N3/9). Sensor data are directly read in from the engine management and indirectly via the CAN network and actuate the control actuators as required. The individual functions and systems of the engine management are controlled and coordinated by the CDI control unit.
The following table provides a model and major assembly overview:
| Sales designation | Model | Motor | Transmission | Engine management | Notes |
|---|---|---|---|---|---|
| Model series 166.0 | |||||
| ML 250 BlueTEC ATIC | 166.006 | 651.960 | 722.908 | CR43 |
The engine management is subdivided into the following systems:
- Base functions
- Engine system
- Fuel injection system
- Air control system
- Exhaust system
Base functions
- Control unit diagnosis
- Fault memory
- European On-Board Diagnosis (EOBD)
- Diagnosis via the Control Area Network (CAN)
- CAN network
- Flash programming and variant coding
- DAS stage 4 (FBS 4)
- Torque coordination
- Thermal management
- Alternator interface
- Synchronization
- Load determination
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.
Transport mode
In transport mode various functions of the engine management are limited. Further information are available in the energy management function. If the kilometer reading of the vehicle is more than 250 km, the system condition "vehicle transport mode" is automatically deactivated and can also not be reactivated anymore using the diagnostic unit.
Variant coding
With variant coding the following vehicle versions and equipment can, for example, be coded using XENTRY Diagnostics:
- Vehicle model
- National version
- Exhaust variant
- Transmission version
Flash programming
The engine management in the CDI control unit is flashable, i.e. the entire software of the control unit can be exchanged (replaced) using Xentry Diagnostics. The software required for control unit programming can be found on the diagnostic system software DVD.
CAN network
The CDI control unit exchanges data via the connected drive train CAN (CAN C), chassis CAN 1 (CAN E1) and drive train sensor CAN (CAN I) (with CODE U77 (BlueTEC (SCR) diesel exhaust treatment)) with other control units that are integrated in the CAN network. The CDI control unit is also connected to the drive-train LIN (LIN C1), via which it exchanges data.
Engine system
- Starter relay actuation
- Throttle valve control
- Safety fuel shutoff
- Transmission overload protection
- Electronic Stability Program control unit support
- Fully integrated transmission control support
- Drive off torque limitation and anti-jerk control
- Fan control
- Alternator regulation and glow time control
- Engine management Start-Stop function
Fuel injection system
- Pre, main and post injection
- Idle speed control
- Rpm limitation
- Smooth running control
- Limp-home function
- A/C rpm increase
- Deceleration fuel shutoff
- Rail pressure regulation
- Fuel pump controlling
- High-pressure pump control
- Altitude adaptation
Air control system
- Exhaust gas recirculation (EGR)
- Boost pressure control
- Intake air throttling through intake port shutoff (EKAS)
Exhaust system
- Catalytic converter heating
- Oxygen sensor heater controlling
- Exhaust aftertreatment, DPF regeneration (Dieselparticulateffilter) with code 474 (Particulate filter)
- Exhaust aftertreatment, injection of the AdBlue® reducing agent with code U77 (BLUETEC (SCR) diesel exhaust gas treatment))
Exhaust emissions standard
Engine 651.9 complies with the EU-5 exhaust emissions standard. Vehicles with CODE U77 (BLUETEC (SCR) diesel exhaust treatment) fulfill the EU-6 exhaust emissions standard or the BIN5 LEVII exhaust emissions standard for USA.
Engine 651 is characterized by the following components:
- 2 Balance shafts
- An oil pump integrated in the crankcase
- Gearwheel drives in combination with a timing chain on the flywheel side for driving the high-pressure pump, oil pump, balance shafts and the two camshafts
- Oil spray nozzle shutoff valve (Y131) for controlling the oil spray nozzles for piston crown cooling
- Switchable coolant pump
- Exhaust gas recirculation (EGR) with coolant-cooled pre-cooler and EGR cooler with switchable bypass duct
- Cylinder head with 2-piece water jacket
- Rapid glowing system with glow output stage (N14/3)
- Load-level controlled preinjection and post injection
- Fuel injectors with piezo technology, 2 turbochargers connected in series with vacuum-controlled boost pressure control flap, a wastegate, a charge air bypass flap and an additional low-pressure turbocharger boost pressure sensor (B5/4)
The operating conditions of the engine and the associated active partial functions of the engine management are described in the following documents:
- Ignition ON, function
- Starting, function
- Ignition OFF, function
- Fuel supply, function
- Injection regulation, function
- Rpm control, function
- Alternator interface, function
- Smooth running control, function
- Thermal management, function
- Torque coordination, function
- Deceleration fuel shutoff, function
- Engine limp-home mode, function
- European OBD, function
- ECO start/stop function engine management, function
- Forced induction, function
- Exhaust treatment, function
- Exhaust gas recirculation, function
- Preheat, function
| Ignition ON, function | GF07.10-P-1000OLF | ||
| Starting, function | GF07.10-P-1001OLF | ||
| Ignition OFF, function | GF07.10-P-1002OLF | ||
| Fuel supply, function | GF07.10-P-1003OLF | ||
| Injection regulation, function | GF07.10-P-1004OLF | ||
| Rpm control, function | GF07.10-P-1008OLF | ||
| Alternator interface function | GF07.10-P-1009OLF | ||
| Smooth running control, function | GF07.10-P-1011OLF | ||
| Thermal management, function | GF07.10-P-1012OLF | ||
| Torque coordination, function | GF07.10-P-1013OLF | ||
| Deceleration fuel shutoff, function | GF07.10-P-1014OLF | ||
| Engine limp-home mode, function | GF07.10-P-1019OLF | ||
| European OBD, function | GF07.10-P-1021OLF | ||
| ECO start/stop function engine management, function | The "Engine management, ECO start/stop function" subfunction is examined from the point of view of the engine management. Information for partial function "Energy management, start/stop function" is documented in the function description "Energy management function". | GF07.10-P-1042OLF | |
| Charging, function | GF09.00-P-2000OLF | ||
| Exhaust treatment function | GF14.00-P-3000OLF | ||
| Exhaust gas recirculation, function | GF14.20-P-3000OLF | ||
| Preheat, function | GF15.20-P-3005OLF | ||
| Overview of system components for common rail diesel injection (CDI) | GF07.16-P-9997OLF |