Fuel Transport to the Crankcase, Oil Dilution and HC Return with Breather Flow During the Cold Operation of a SI Engine University of Nottingham

Format:

Book

Conference/Event

Author/Creator:

Shayler, P. J., author.

Conference Name:

SAE 2000 World Congress (2000-03-06 : Detroit, Michigan, United States)

Language:

English

Physical Description:

1 online resource cm

Place of Publication:

Warrendale, PA SAE International 2000

Summary:

Fuel losses to the crankcase, fuel/oil interactions, and fuel return as unburned hydrocarbons in the breather flow have been investigated. Hydrocarbons in the breather flow have been measured during motored and firing engine operation over a range of temperatures. Fuel desorption from the sump oil accounts for a small proportion of this. The major source is hydrocarbons transported past the piston with blowby. After a cold start, around 85% of these are retained in oil films below the ring pack. The recirculation of oil from the films to the sump contributes to bulk oil dilution. This appears to be the prime mechanism by which fuel is lost to oil dilution during cold operation. The mechanism becomes less effective as engine warm-up progresses. At fully-warm oil temperatures (100°C), only about 5% are removed from the blowby. Under steady operating conditions which maintain oil temperature at around 100°C, the rate of absorption is balanced by desorption from the sump oil when dilution levels reach 1-2%. At an oil temperature of 70°C, the equilibrium dilution level is typically 2-4%

Notes:

Vendor supplied data

Publisher Number:

2000-01-1235

Access Restriction:

Restricted for use by site license