Diesel fuel applications

System schematic for diesel fuel applications

The fuel water emulsion is circulated by the circulation pump (13) in a closed circuit through the injection pumps. The circuit is consisting, besides the connecting pipes and injection pumps, of mixing chamber (12), circulation pump (13), water/fuel sensor (14) and fuel intercooler (17).

Inside the mixing chamber, supplied by the fuel pump of the diesel engine, the fuel is forced into a strong circulation, into which the water is injected, in the necessary quantity, with a pressure of 10-15 bar supplied by pressure pump (2). In addition the emulsion returning from the injection pumps is permanently forced through the mixing chamber, which results in the fact, that water and fuel are kept away from separating again. This is also the case during standstill of the engine as long as the circulation pump (13) is running.

This avoids corrosion problems in injection pumps and nozzles and results in the ability to start the engine even with emulsion in the system without any problems.

Before stopping the engine for a longer period the water content must be reduced to less than 3%, the solubility limit of water in fuel.

The required water content is controlled by the ECU, based on a load depending characteristic map, within a tolerance of app. 1%.  The actual water content is determined evaluating the signal of a Water in Fuel sensor.

During reduction of water content the response to load changes is depending on the fuel consumption of the engine and the circulating emulsion volume. During increase of water content the rate is solemnly controlled by the ECU and depends on a linear transition ramp.

Engine load / water content will be controlled, depending on the installation, using one of the following methods:

  1. Up to 4 external digital signals, defining up to 8 water contents. (depends on external (engine) controller).
  2. External analog signal defining a water content set point. (depends on external (engine) controller).
  3. External analog signal defining an engine load. Water content controlled based on a engine characteristic map. (depends on external load signal)
  4.  Engine load metered based on flow meter (10). Water content controlled based on a engine characteristic map. (stand alone operation)

Methods 1-3 are included in the standard package, Method 4 optionally, preferred for mobile or retrofit applications.

Desalinate water, supplied from exhaust gas boilers of the ship, can be used if available. Otherwise drinking water is suitable.