Common rail diesel injection (CDI), function - GF07.16-P-0001OG

ENGINE 642.8 in MODEL 204, 207, 212, 218 

Common rail diesel injection (CDI), general points 

The C  ommon-Rail D  iesel I  njection (CDI) forms the engine management "CR-6+" as an electrical network in combination with sensors and actuators on engine 642.8 and the engine management "CR-60" for vehicles with code B03 (ECO start/stop function) or an increased engine power (195 kW).

The short designation "CR-6+", "CR-60" and "CR-61" means:

CR = Common Rail 

6+, 60, 61  are the running Daimler project numbers

The "common rail" is the line shared by all injectors for fuel delivery. In this common line, the fuel is stored temporarily before injection. Therefore a common rail system is also called "storage injection".

The entire engine management system is located in the CDI control unit (N3/9).

Sensor data are read in directly by the engine management and indirectly via the CAN network and the respective actuators are actuated. The individual functions and systems of the engine management are controlled and coordinated by the CDI control unit.

The following table provides an overview of the vehicle model and major assembly overviews:

The engine management is subdivided into the following systems:

• Base functions 
• Engine system 
• Diesel injection system 
• Air control system 
• Exhaust system 

Base functions 

• Control unit diagnosis
• Fault memory
• European OBD II (OBD II)
• Diagnosis via the CAN bus
• CAN network
• Flash programming
• Variant coding
• DAS stage 4 (FBS 4)
• Torque coordination
• Thermal management
• Alternator interface
• Maximum speed limit
• 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.

CAN network

The CDI control unit exchanges data over the attached drive train CAN (CAN C) and chassis CAN (CAN E) (model 204, model 207/212/218 up to model year 14/YoM 13 facelift) or chassis CAN 1 (CAN E1) model 207/212/218 as of model year 14/YoM 13 facelift) with other control units which are integrated into the CAN network.

The CDI control unit also acts as the interface (gateway) between the two CAN bus systems. The CDI control unit can also be attached to the drive LIN (LIN C1) and to the drive train sensor CAN (CAN I) with code U42 (BlueTEC (SCR) diesel exhaust treatment) (model 212, 218 up to 31.08.2014, 218), for with code U77 (BlueTEC (SCR) diesel exhaust treatment) (model 207, 212 as of 1.09.2014, 218 as of 1.09.2014) and exchanges data over it.

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 Star Diagnosis software DVD.

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 ESP®
• Support for fully integrated transmission control (VGS)
• Driving on torque limitation
• Anti-jerk control
• Suction fan actuation
• Alternator regulation
• Glow time control

Diesel injection system 

• Pre, main and post injection
• Idle speed control
• 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
• Rpm limitation

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 (DieselParticulateFilter) with code (474) Particulate filter)
• Exhaust aftertreatment, injection of the AdBlue® reduction agent with code U42 (BlueTEC (SCR) diesel exhaust treatment) (model 212 up to 31.08.2014, 218 up to 31.08.2014), with code U77 (BlueTEC (SCR) diesel exhaust treatment) (model 207, 212 as of 1.09.2014, 218 as of 1.09.2014)

Engine 642.8 is characterized by the following components:

• V6 crankcase made out of aluminum instead of cast iron
• Balance shaft located in the "V" of both cylinder heads which turns in an opposite direction to the crankshaft
• Valve assembly with roller cam followers
• Rapid glowing system with glow output stage (N14/3)
• A flow-dynamics optimized forced induction system consisting of a ATL with variable turbine geometry
• Exhaust gas recirculation with water-cooled exhaust gas recirculation cooler
• Highly efficient ventilation system with centrifugal oil separator
• Fuel injectors (Y76) with piezo technology
• Intake controlled high-pressure pump with lower than average operating energy input, which leads to reduced fuel consumption

Exhaust emissions standard

Engine 642.8 fulfills the EU5 exhaust emissions standards.

Vehicles with code U42 (BlueTEC (SCR) diesel exhaust treatment) (model 212 up to 31.08.2014, 218 up to 31.08.2014), with code U77 (BlueTEC (SCR) diesel exhaust treatment) (model 207, 212 as of 1.09, 2014, 218 as of 1.09.2014) fulfill the EU6 exhaust emissions standards or the BIN5 LEVII exhaust emissions standards of the USA.

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 
• Engine management, start/stop function (with code B03 (ECO start/stop function)) 
• Forced induction, function 
• Exhaust treatment, function 
• Exhaust gas recirculation, function 
• Preheat, function