Technician A says that the intake and exhaust valves are both closed during most of the power stroke. Technician B says that the intake and exhaust valves are both closed during most of the compression stroke. Who is right?
A)Technician A only
B)Technician B only
C)Both A and B
D)Neither A nor B

Question

Quizplus · Accepted Answer

Both technicians are correct. During the power stroke, the intake and exhaust valves are closed to allow the combustion gases to expand and push the piston down. Similarly, during the compression stroke, both valves are closed to compress the air-fuel mixture before ignition.

Technician a Says That the Intake and Exhaust Valves Are