Patent ID: 9556802
Date: 2017-01-31
CPC Classifications: F02B,F02D,G01M,Y02T

Claim:
1. A method for detecting coking in an intake tract of an internal combustion engine having direct fuel injection and variable intake valve control, the method comprising the acts of: operating the internal combustion engine in idle at an idle speed that is increased compared to normal idle operation; controlling an opening time of the intake valves to achieve an early timing event; determining a rough running characteristic of the internal combustion engine which is typical of rough operation of the internal combustion engine, wherein presence of coking in the intake tract is detectable based on the determined rough running characteristic; and issuing a notice based on the determined rough running characteristic, the notice including at least one of notice of the presence of the rough running characteristic, notice of the presence of coking, and notice of a need for intake tract cleaning, wherein the notice is issued to at least one of