Which of the following statements correctly describes the position of the intake and exhaust valves during most of the power stage in a four-cycle gas engine?

ABoth the intake valve and the exhaust valve are open.
BThe intake valve is open and the exhaust valve is closed.
CThe intake valve is closed and the exhaust valve is open.
DBoth the intake valve and the exhaust valve are closed.

Both valves are closed during the power stroke.

While the fuel is burning in the cylinder, you want
all the force of the expanding gases to push the
piston down ... you don't want any of the gases
or their pressure escaping.

If either of the valves was open, even just a crack,
then part of the gases would go blooey out the valve,
and some pressure would be lost that's supposed to be
pushing the piston.

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lillaayyy7 lillaayyy7 · Answer 2 · 2018-08-15T11:02:36-04:00

Which of the following statements correctly describes the position of the intake and exhaust valves during most of the power stage in a four-cycle gas engine?

A. The intake valve is closed and the exhaust valve is open.

B. The intake valve is open and the exhaust valve is closed.

C. Both the intake valve and the exhaust valve are closed.

D. Both the intake valve and the exhaust valve are open.