Internal Combustion Engines
The exhaust valve in a four stroke cycle petrol engine

Opens at bottom dead center and closes at top dead center
Opens at 50° before bottom dead center and closes at 15° after top dead center
May open and close anywhere
Opens at 50° after bottom dead center and closes at 15° before top dead center

ANSWER DOWNLOAD EXAMIANS APP

Internal Combustion Engines
Scavenging air in diesel engine means

Air used for combustion sent under pressure
Air used for forcing burnt gases out of engine's cylinder during the exhaust period
Burnt air containing products of combustion
Forced air for cooling cylinder

ANSWER DOWNLOAD EXAMIANS APP