Question

Technician A says that the fuel mixture is ignited at the beginning of the power stroke. Technician B says that the intake valve opens at the bottom of the power stroke. Who is right?

Answer 1

Technician A is correct

Step-by-step explanation:

The power stroke starts after the compression stroke, the piston is at Top Dead Center, and the valves are closed. At the beggining of it, the mixture is ignited (spark in Otto engines, by the pressure in Diesel Engines) so, technician A is correct. At the end of power stroke, the exhaust stroke starts. In this stroke, the EXHAUST valve is open, to let the gases flow out of the cylinder as the piston goes from the Bottom Dead Center to the Top Dead Center. Therefore Technician B is incorrect.