[Retracted] Influence of Sulfur and Additives on Wear of Exhaust Valve Seat of Cylinder Head

Table 6

Inspection results of exhaust valve.

Items	Contact surface	Noncontact surface	Run time
0#	Black discontinuous deposit, valve disc is not worn, corresponding valve seat wear	Blue	20 hours
0#+	Dark black continuous deposits, valve disc is not worn, valve seat is not worn	Dark brown	20 hours
−10#	Dark black continuous deposits, valve disc is not worn, valve seat is not worn	Black carbon deposit	20 hours
−10#+	Dark black continuous deposits, valve disc is not worn, valve seat is not worn	Dark brown	20 hours