Question 215Motor Plants - 1st Asst/Chief

70% to pass

Oil in a scavenging air space on a slow-speed diesel engine can be ignited by which of the following?

AExcessive piston ring blow-by.
BBurned exhaust valve seat.
CHot main bearing.
DEarly fuel injection.
AI Explanation

The correct answer is A) Excessive piston ring blow-by. Excessive piston ring blow-by can allow oil to enter the scavenging air space, where it can be ignited by the high temperatures present. This is due to the combustion gases being able to bypass the piston rings and enter the crankcase, bringing oil with them. The other options, such as a burned exhaust valve seat, hot main bearing, or early fuel injection, do not directly relate to the presence of oil in the scavenging air space and its potential for ignition.

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