Closed
During the power or combustion stage of a piston cycle, both valves are necessarily closed, because the expansion of gases is driving the piston down.
They are closed during the power stage.
-intake: exhaust closed, intake open -compression: exhaust closed, intake closed -combustion: exhaust closed, intake closed -exhaust: exhaust open, intake closed
Closed
Closed.
Closed
Both the intake and the exhaust valve are closed.
Closed
Upright (this is the correct answer for MSF question #6)
Is the time when intake and exhaust valve remain oper during the exhaust stroke.
Is the time when intake and exhaust valve remain oper during the exhaust stroke.
Is the time when intake and exhaust valve remain oper during the exhaust stroke.