A method for operating a direct-injection diesel engine and an IC engine

Abstract

The invention relates to a method for operating a direct-injection Diesel engine that comprises at least one piston, reciprocating in a cylinder, whereby the internal combustion engine is operated in such a manner that the fuel is substantially combusted at a local temperature below the Nox formation temperature and at a local air ratio above the soot formation limit. Fuel injection is started in a crank angle range of between 2 DEG before the upper dead center and up to approximately 10 DEG after the upper dead center of the compression phase and exhaust gas is returned, the exhaust gas return rate amounting to approximately 20 % to 40 %. The aim of the invention is to achieve particularly low nitrogen oxide and soot emissions. For this purpose, at least one piston (27) is provided with a squish area (34) and a toroid piston recess (28) and a necking (29) in the transition area between the squish area (34) and the piston recess (28). When the piston (27) moves upward a squish flow is produced which flows from the outside to the inside of the piston recess (28) and a turbulent swirl (43, 43a) within the piston recess (28) is initiated. At least the major portion of the fuel is injected into the toroid piston recess (28) and is transported along the piston recess wall (31) and / or the piston head (32) while at least partially evaporating.

Description

technical field [0001] The invention relates to a method for operating a direct injection diesel internal combustion engine with at least one reciprocating piston in a cylinder, wherein the internal combustion engine is operated such that the fuel is substantially at a local temperature below the NOx formation temperature and at a temperature above The local excess air ratio of the soot formation limit is carried out for combustion, wherein the fuel injection starts in the range between 2° of crank angle before top dead center of a maximum of approximately 10° of crank angle after top dead center of the compression phase and recovers exhaust gases, where , The waste gas recovery rate is about 20%-40%. Furthermore, the invention relates to an internal combustion engine for carrying out the method. Background technique [0002] The most important parameters of the combustion process in internal combustion engines with internal combustion are the phase of the combustion proces...

AI Technical Summary

Problems solved by technology

[0008] In internal combustion engines operating according to the HPLI method, such a piston configuration with a deeply constricted piston-cone combustion chamber has not been used until now, because it was thought until now that due to the deep piston-cone combustion chamber and the strong squeeze-flow starting capability and thermodynamic efficiency will become too poor

Images