DIESEL ENGINE ARRANGEMENT AND METHOD FOR VARNISH BUILD-UP CONTROL

摘要

A method is provided for controlling varnish build-up in a variable geometry turbine (VGT) of a diesel engine turbocharger. According to the method, it is determined whether an operation parameter is at a level established for initiating a varnish build-up control sequence. Upon determining that the operation parameter is at the established level, the varnish build-up control sequence is initiated. The sequence comprises increasing exhaust temperature upstream of the VGT to a first exhaust temperature, and changing an opening size of a VGT nozzle between a smaller and a larger opening size in association with increasing the exhaust temperature to the first exhaust temperature. A diesel engine arrangement is also provided.