Fuel and auxiliary fluid injection system for an internal combustion engine

An injection system for combined injection of a combustible fuel, especially Diesel fuel, and an auxiliary fluid, especially water, into at least one combustion chamber of an internal combustion engine, especially a Diesel engine, comprising at least one injection nozzle (10), associated with the at least one combustion chamber, for fuel injection, said nozzle has a nozzle body (11) with an injection opening (12) and a nozzle chamber (13) preceding said injection opening that communicates with first and second separate nozzle connections (15, 16), and a nozzle needle (14) that closes the injection opening (12) and opens under injection pressure;

• a fuel injection pump with at least one pump piston for pumping fuel that is at an injection pressure to at least one supply outlet that communicates via an equal-pressure valve (17) with said first nozzle connection (15) of the injection nozzle (10);
• a metering device (25), that communicates via a downstream check valve (18) with said second nozzle connection (16) of the injection nozzle (10), for introducing a quantity of auxiliary fluid into the nozzle chamber (13) of the injection nozzle (10), said metering device has a prefeed pump (31) and a pressure generator (33) that by imposition of fuel from the fuel injection pump (23) generates a fluid pressure in a metering line (34) that is above a standing pressure maintained by the equal-pressure valve (17) in the nozzle chamber (13) of the injection nozzle (10) when fuel injection is not occurring;
• and having a magnet valve assembly (27), disposed between the fuel injection pump (23) and the pressure generator (33), for acting upon the pressure generator (33) with fuel, said magnet valve assembly is capable of opening a relief line (40), the connection of the magnet valve assembly, toward the fuel injection pump, is affected at the at least one supply outlet preceding the equal-pressure valve (17), and that the magnet valve assembly (27) is controlled such that during the supply stroke of the pump piston of the fuel injection pump (23), the magnet valve closes at the onset of fuel supply, and opens at the end of injection, and for a predetermined duration of the remaining supply stroke of the pump piston, connects the supply outlet of the fuel injection pump (23) to the pressure generator (33) of the metering device (25).