Electronic Diesel Control

Electronic Diesel Control (EDC) is a system developed by Bosch injection system for diesel engines. Other major producers are Continental, Delphi and Denso.

Operation

The electronic diesel control enables precise control of the temporal injection behavior and a more precise amount of fuel allocation as a mechanical control. Modern injection systems such as common rail are made ​​possible by the EDC.

This succeeds by the working principle of "EVA" ( input - processing - output ). In the EVA principle, the signals are combined by the sensors in the control unit maps, handle and control the actuators of this. The electronic control of the injection system has the following advantages:

  • Compliance with more stringent emission limits
  • Reduction in fuel consumption
  • Optimization of torque and power
  • Reduction of engine noise
  • Optimization of the smoothness
  • Improvement of the response
  • Easy adaptation of the vehicle with a cruise control
  • Simplified adjustment of an engine type to different vehicles

The EDC control unit is next to the ESP one of the most powerful and most sophisticated equipment in the vehicle. Here not only a lot of input and output signals are processed, but this must be done in real time, according to the speed, the number of cylinders of the engine and still many other conditions. The core of the hardware is a microcontroller with flash memory in the software of the order in the megabyte range runs. Other functions of the controller are:

  • Communications to other controllers via high-speed CAN bus
  • Self-diagnosis control unit / detect errors and save
  • / Recognize and store diagnosis of sensors and actuators fault
  • Monitoring of engine operating conditions including safety shutdown
  • Control of the exhaust system with particulate filter and catalyst
  • Diagnostic interface via the communication protocol KWP2000
  • Immobilizer

Functional differences EDC control devices differ only slightly for passenger cars and commercial vehicles, at first glance, upon closer examination, however, there are some differences:

All injection pumps consist of a low-pressure feed pump, which pumps the fuel from the tank into the actual high-pressure pump. The high-pressure pump generating the injection pressure.

EDC for distributor injection pumps

In dispensing pumps the high pressure pump provides not only the generation of the injection pressure for the distribution of the fuel to the injector of each cylinder.

Quantity adjusting mechanism - regulation of the injection quantity

The injection quantity is controlled by the control unit on the quantity adjusting mechanism. The quantity adjusting mechanism consists of a rotary magnet, and a shaft position sensor. The shaft moves the control slide about an eccentric pin in the predetermined direction by the control unit, wherein the spill port is released earlier or later. This can happen so fast that up to medium speeds, the spill port can be changed individually for each cylinder.

Electronically controlled injection timing

The inverse of the speed pump interior pressure acts on a clocked solenoid valve on the injection actuator, causing it to change the start of injection on the roller ring.

EDC for pump - nozzle

During the injection pressure during the pump-nozzle system without electronic intervention is constructed by a cam, the control unit can, via a solenoid valve short-circuiting the pressure chamber, and thus, for example, produce two consecutive injections of a pressure stage by means of intermediate drive. The valve enables a change of the injection start and control duration during the printing phase.

EDC for Common Rail

The common-rail system, the functions of the control unit are located in the very precise calculation of the top dead center, the injection -specific parameters, the correct actuation of the injectors and the rail pressure control.

Other tasks of the control unit are largely independent of the injection system.

Sensors & Actuators

Electronic sensors:

  • Speed ​​encoder motor camshaft sensor as phase sensor
  • Air inlet temperature sensor
  • Mass flow sensor intake air
  • Atmospheric pressure sensor ( ambient pressure )
  • On the turbocharger boost pressure sensor output
  • Rail pressure sensor in the high-pressure system in Common Rail systems
  • Broadband lambda probe
  • Exhaust gas temperature sensors on the turbocharger and the lambda probes
  • Differential pressure sensor on the diesel particulate filter
  • Fuel temperature sensor
  • Coolant temperature sensor
  • Pedal position sensor
  • Clutch pedal switch
  • Brake pedal switch
  • Regelschieberwegpotentiometer in older injection systems
  • Needle movement sensor on the first injector at distributor pump systems
  • Cylinder pressure sensor with pressure controlled combustion process

Electric actuators:

  • Cylinder individual control of the injectors in the common rail engine
  • Servo motor or magnetic drive for the boost pressure control
  • Actuator for variable geometry turbocharger
  • Throttle in support of the exhaust gas recirculation and the interruption of the air supply for smooth stopping the engine
  • Valve for exhaust gas recirculation,
  • Quantity control valve for the inlet volume control of the high -pressure pump in a common rail engine
  • Pressure control valve in a common rail engine
  • Fuel cut
  • Quantity adjusting mechanism for moving the control slide
  • Solenoid valve injection timing ( start of injection )
  • Glow plugs ( possibly via additional control unit )
  • Motor fan ( possibly via additional control unit )
Robert Bosch GmbH Continental AG Real-time AUTOSAR
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