Abstract
It is generally acknowledged that NOx emissions and unburned gasoline from engines play an important role in their formation of low-temperature sludge. This report describes the process by which unburned gasoline is absorbed into the engine oil. This was clarified by analyzing the blowby gas condensate, crankcase gas condensate and engine oil. It was found that unburned gasoline is mainly absorbed into the oil through oil film on the cylinder wall and oil in the ring grooves, and it is vaporized from the oil in the crankcase. The effects of the engine operating conditions on the quantity of unburned gasoline in the oil and the crankcase gas were also clarified, as well as their effects on the composition of the unburned gasoline in the crankcase gas.
