MAN Trucks EDC Electronic Diesel Control Repair Manual

MAN Trucks EDC Electronic Diesel Control Repair Manual
MAN Trucks EDC Electronic Diesel Control

Dear Customer
These instructions are intended to help you properly carry out repairs on the electronically controlled diesel injection system described in this document. In writing these instructions, we have assumed that you have the necessary knowledge of control systems for working on and with the electronic diesel control.

Limitation of liability for parts and accessories
In your own interest, we strongly recommend you use only accessories and original MAN parts expressly approved by MAN for your MAN engine. The reliability, safety and suitability of these parts and accessories have been tested specially for MAN engines. Despite us keeping a constant eye on the market, we cannot assess and be held responsible for these properties in other products, even if they bear TÜV (German testing and inspection institute) approval or any other official approval in any particular case.

Laying up or storage
Special measures must be implemented in accordance with MAN Company Standard M 3069 Part 3 if engines are to be laid up or placed into storage for more than 3 months.

Electronic diesel control EDC
The requirements set by customers and legislation in respect of fuel consumption, exhaust emission and noise characteristics etc. on diesel engines have grown over the years and will be even more stringent in the future. The fact that conventional mechanical injection systems have reached their performance limits has made electronically controlled fuel injection systems necessary. Such systems increase engine efficiency, improve driving comfort and lessen the burden on the environment. EDC (Electronic Diesel Control) meets these requirements.

System description EDC M(S) 5

System EDC M(S) 5

The controller contains

  • the linear solenoid
  • the control rod position transducer

The linear solenoid is actuated by the electronic control unit. The control unit processes information which it receives via

  • the control rod position transducer
  • the drive position selection
  • drive stage selection
  • coolant temperature sensor
  • charge-air temperature sensor
  • intermediate engine speed setpoint
  • and the rpm sensors.

The diagnosis request push button and the EDC indicator lamp are used in detecting faults and signalling them through a code. An ISO interface provides a communication with the MAN-cats test and diagnostic computer. The control unit, with its program adapted to the engine model concerned, determines the optimum setting of the control rod from all the measured values.

To ensure the vehicle can still be driven to the nearest workshop in the event of one or several sensors failing, an emergency drive function is integrated in the control unit which, depending on the situation, makes it possible to continue driving with restricted functions. When the brakes are applied, the system operates as an intermediate engine speed controller with a cyclic irregularity (P-degree) of 0, i.e. a set intermediate engine speed is maintained exactly provided the engine develops sufficient power output for this purpose.

The idle speed control operates in the same way as the intermediate engine speed control. The idle speed is exactly maintained by means of the idle speed governor as long as the engine output is sufficient for this. The regulated idle speed can be varied within certain limits.

Starting-fuel delivery is output when either a lower start recognition speed is exceeded. The starting fuel volume and cold idle speed are limited as a function of the coolant temperature to avoid impermissible smoke emission and unnecessary revving of the engine after starting.