Method of operating directly injecting diesel engine

Abstract

The invention relates to a method for operating a direct-injection Diesel engine that comprises at least one piston (27), reciprocating in a cylinder (24), whereby the internal combustion engine is operated in such a manner that the fuel is 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 50 DEG and 5 DEG before the upper dead center of the compression phase and exhaust gas is returned, the exhaust gas return rate amounting to approximately 50 % to 70 %. 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 (43) is produced which flows from the outside to the inside. At least the major portion of the fuel is injected into the toroid piston recess (28) and is transported by the squish flow (43) along the piston recess wall (31) and / or the piston head (32).

Description

technical field [0001] The invention relates to a method for operating a direct injection diesel internal combustion engine with at least one piston reciprocating in a cylinder, wherein the internal combustion engine is operated such that the fuel is at a local temperature below the NOx-forming temperature and at a temperature above Soot formation Combustion at extreme local air ratios where fuel injection starts before top dead center in the compression phase and exhaust gas recovery in the range between 50° and 5° of crank angle where exhaust gas recovery is about 50%- 70%. 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 an internal combustion engine with internal combustion are the phase of the combustion process or the start of combustion, the maximum rate of rise of the cylinder pressure and the peak pressure. [0003] In internal c...

AI Technical Summary

Problems solved by technology

[0009] In internal combustion engines operating according to the HCLI method, such a piston configuration with a deeply constricted piston bowl combustion chamber has not been used until now, because it was thought until now that due to the deep piston bowl combustion chamber and the strong squeeze flow starting capacity and thermodynamic efficiency can become too poor

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