Patent ID: 7207311

Claim:
A method for operating a direct injection diesel internal combustion engine, which is operated in a first operating region corresponding to low to medium load in such a way that combustion of the fuel takes place at a local temperature below the temperature of NO x formation and with a local air ratio above a ratio at which particulates are formed, and in which fuel injection is initiated at a crank angle of between 50° to 5° before top dead center of a compression phase and exhaust gas is recirculated at an exhaust gas recirculation rate of 50% to 70%, wherein in a second operating region corresponding to medium partial load, fuel injection is started in a range from approximately 2° crank angle before top dead center to approximately 20° crank angle after top dead center, wherein exhaust gas is recirculated in the second operating region at an exhaust gas recirculation rate between 20% and 40%, wherein fuel injection in the first operating region uses an injection pressure between 400 to 1,000 bar, wherein fuel injection in the second operating region uses an injection pressure of at least 1,000 bar, wherein in a third operating region corresponding to high partial load or full load, start of the main part of fuel injection occurs in a range from −10° to 10° crank angle after top dead center, and wherein the effective mean pressure in the third operating region is at least 5.5 bar.