A method for using partial homogeneous charge compression ignition in a diesel internal combustion engine for NOx trap regeneration

摘要

A method for operating a diesel IC-engine 19 being able to run in a conventional mode and in a partial Homogeneous Charge Compression Ignition (pHCCl) mode. The method comprises the features of switching the pHCCl mode from lean pHCCl to rich pHCCl as a response to a control signal indicating that the NO x -absorbent shall be regenerated. In the rich pHCCl mode, the ratio of recirculated exhaust gases is from 20 to 55% and the. The rich pHCCl mode further comprises the feature of injecting at least 70% of the fuel to be injected in each working cycle in the main injection whereby the central axis of the fuel spray is directed towards the piston bowl cavity. The method will increase the operation window for rich pHCCl which in turn will have the benefits of less oil dilution and better fuel economy while regenerating the NO x -absorbent.