Method for operating a reciprocating-piston internal combustion engine

A method for operating a reciprocating-piston internal combustion engine having a crank angle and an injector nozzle for directly injecting fuel into a working space of a cylinder, the working space including a recess of a piston, the engine capable of operating in a lower part-load range, a middle part-load range, an upper part-load range, and a full-load range, the method comprising:

• during the lower part-load range, forming an ignitable homogeneous mixture locally by defined charge stratification using controlled coordination of air movement in the working space and injection pressure combined with timed injection at a time when the crank angle is between 180° and 20° before the top dead center position so as to produce a homogeneous combustion;
• during the middle part-load range, injecting a second amount of the fuel into the working space at a second injection pressure at a time when the crank angle is between 180° and 20° before the top dead center position so as to produce a homogeneous mixture;
• and
• during at least one of the upper part-load range and the fall-load range, injecting a portion of a third amount of the fuel into the working space at a third injection pressure at a time when the crank angle is within a range between 180° and 20° before the top dead center position so as to produce a homogeneous mixture and a remainder of the third amount of the fuel into the working space at a fourth injection pressure at a time when the piston is approximately at the top dead center position so as to produce a heterogeneous mixture.

An injection system for a reciprocating-piston internal combustion engine having a crank angle and an injector nozzle for directly injecting fuel into a working space of a cylinder, the working space including a recess of a piston, the engine capable of operating in a lower part-load range, a middle part-load range, an upper part-load range, and a full-load range, the injection system comprising:

• a reciprocating piston pump for generating pressure modulation in a working cycle including a piston driven by a camshaft having a double cam for feeding fuel to the electronically controllable injection valve;
• an injection nozzle;
• and
• a cut-off valve disposed between the reciprocating piston pump and the injection nozzle, the reciprocating piston pump being capable of, during the lower part-load range, injecting a first amount of the fuel centrally into the working space at a first injection pressure at a time shortly before the crank angle reaches a top dead center position so as to produce a heterogeneous mixture;
• during the middle part-load range, injecting a second amount of the fuel into the working space at a second injection pressure at a time when the crank angle is between 180° and 20° before the top dead center position so as to produce a homogeneous mixture;
• and during at least one of the upper part-load range and the fill-load range, injecting a portion of a third amount of the fuel into the working space at a third injection pressure at a time when the crank angle is within a range between 180° and 20° before the top dead center position so as to produce a homogeneous mixture and a remainder of the third amount of the fuel into the working space at a fourth injection pressure at a time when the piston is approximately at the top dead center position so as to produce a heterogeneous mixture.

An injection system for a reciprocating-piston internal combustion engine having a crank angle and an injector nozzle for directly injecting fuel into a working space of a cylinder, the working space including a recess of a piston, the engine capable of operating in a lower part-load range, a middle part-load range, an upper part-load range, and a full-load range, the injection system comprising:

• a CR system for generating pressure modulation in a working cycle, the CR system including a high pressure accumulator, an electronically controllable injection valve including a fuel delivery line, a quick-switching magnetically or piezoelectrically controlled valve disposed between the accumulator and the injection valve and capable of aiding regulation of a pressure level in the fuel delivery line,
• the CR system being capable of, during the lower part-load range, injecting a first amount of the fuel centrally into the working space at a first injection pressure at a time shortly before the crank angle reaches a top dead center position so as to produce a heterogeneous mixture;
• during the middle part-load range, injecting a second amount of the fuel into the working space at a second injection pressure at a time when the crank angle is between 180° and 20° before the top dead center position so as to produce a homogeneous mixture;
• and during at least one of the upper part-load range and the full-load range, injecting a portion of a third amount of the fuel into the working space at a third injection pressure at a time when the crank angle is within a range between 180° and 20° before the top dead center position so as to produce a homogeneous mixture and a remainder of the third amount of the fuel into the working space at a fourth injection pressure at a time when the piston is approximately at the top dead center position so as to produce a heterogeneous mixture.

An injection system for a reciprocating-piston internal combustion engine having a crank angle and an injector nozzle for directly injecting fuel into a working space of a cylinder, the working space including a recess of a piston, the engine capable of operating in a lower part-load range, a middle part-load range, an upper part-load range, and a full-load range, the injection system comprising:

• an electronically controllable injection system with hydraulic pressure boosting, the electronically controllable injection system being capable of, during the lower part-load range, injecting a first amount of the fuel centrally into the working space at a first injection pressure at a time shortly before the crank angle reaches a top dead center position so as to produce a heterogeneous mixture;
• during the middle part-load range, injecting a second amount of the fuel into the working space at a second injection pressure at a time when the crank angle is between 180° and 20° before the top dead center position so as to produce a homogeneous mixture;
• and during at least one of the upper part-load range and the full-load range, injecting a portion of a third amount of the fuel into the working space at a third injection pressure at a time when the crank angle is within a range between 180° and 20° before the top dead center position so as to produce a homogeneous mixture and a remainder of the third amount of the fuel into the working space at a fourth injection pressure at a time when the piston is approximately at the top dead center position so as to produce a heterogeneous mixture.