Combustion Preheating System Digital Diesel Electronics (DDE7.3): Notes

In contrast to the ECE version of the M57TU2TOPPING engine, the engine in the US project has a glow system with LIN bus connection and ceramic glow plugs.

The glow system ensures reliable cold starting characteristics and smooth engine operation when the engine is cold. The DDE control module transmits the glow plug heating request to the combustion preheating control module. The combustion preheating control module puts the request into effect by activating the glow plugs by means of a pulse-width modulated signal. In addition, the combustion preheating control module reports diagnosis and state information across the LIN bus connection to the DDE.

The LIN bus is a bidirectional data interface base on the master-slave principle, whereby the DDE is the master controller.

Each of the six glow plug circuits can be diagnosed individually.

The required glow plug temperature is determined by the DDE control module on the basis of the following operating values:

• Engine speed
• Intake air temperature
• Injection volume
• Vehicle voltage
• Status signal for starter enable