Piston Engine Ignition Timing Quiz

When does ignition of the fuel/air mixture occur in a four-stroke piston engine?

What is the typical timing for ignition in relation to Top Dead Center in a piston engine?

Which strokes involve the piston moving upwards in a piston engine?

What does the term 'valve overlap' refer to in a four-stroke engine?

At what point does valve lag occur in relation to the piston’s position?

What is the correct sequence of operation for the four strokes of a piston engine?

What does the term 'valve lead' mean in the context of valve operation?

How does increasing the RPM of an aircraft’s piston engine affect ignition timing?

What is the primary purpose of a cowl-flap in an engine?

What role does 'alternate air' play in a fuel injection system?

The combustion of the fuel-air mixture in a piston engine occurs during the compression stroke.
The ignition timing is typically between 20° and 25° before the piston reaches Top Dead Center (TDC) during the compression stroke.
The piston engine ignition timing is not affected by changes in RPM.

Valve overlap occurs between the exhaust and induction strokes.
The correct sequence of four-stroke engine operation is: Induction, compression, power, exhaust.
Valve overlap refers to the brief period where the inlet and exhaust valves are open simultaneously around TDC.
Valve lag occurs when the inlet valve closes after the piston passes BDC.
Valve lead occurs when the inlet valve opens before the piston reaches TDC.

Alternate air in a fuel injection system is air drawn from the engine cowling and directed to the induction system.
Cowl flaps are used to control airflow over the engine cylinders, ensuring optimal operating temperatures.