Sample-MODULE 16. PISTON ENGINE.

Question Number  1	.	Valve overlap is defined as the number of degrees of crankshaft travel.		
Option A.	during which both valves are off their seats.	
Option B.	between the closing of the intake valve and the opening of the   exhaust valve.	
Option C.	during which both valves are on their seats.	
Correct Answer is.	during which both valves are off their seats.	
Explanation.	The intake valve opens before the exhaust valve closes permitting better volumetric efficiency and lowers cylinder temperature.	


Question Number  2	.	Full floating piston pins (or gudgeon pins) are those which allow motion between the pin and.		
Option A.	the  piston.	
Option B.	both the piston and the connecting rod.	
Option C.	the connecting rod.	
Correct Answer is.	both the piston and the connecting rod.	
Explanation.	Powerplant Handbook for Mechanics E A-AC65-12A page 15 refers.	

Question Number  3	.	Which statement is correct regarding a four-stroke cycle aircraft engine?.		
Option A.	The intake valve closes on the compression stroke.	
Option B.	The exhaust valve opens on the exhaust stroke.	
Option C.	The intake valve opens on the intake stroke.	
Correct Answer is.	The intake valve closes on the compression stroke.	
Explanation.	See CAIP's leaflet E L/1-1 valve timing diagram.	


Question Number  4	.	The five events of a four-stroke cycle engine in the order of their occurrence  are.		
Option A.	intake, ignition, compression, power, exhaust.	
Option B.	intake, power, compression, ignition, exhaust.	
Option C.	intake, compression, ignition, power, exhaust.	
Correct Answer is.	intake, compression, ignition, power, exhaust.	
Explanation.	known as the Otto cycle or Constant Volume Cycle.	


Question Number  5	.	On which stroke or strokes are both valves on a four-stroke cycle reciprocating engine cylinder open?.		
Option A.	Exhaust.	
Option B.	Intake.	
Option C.	Exhaust and intake.	
Correct Answer is.	Exhaust and intake.	
Explanation.	See CAIP's leaflet E L/1 -1 valve timing diagram.	


Question Number  6	.	The actual power delivered to the propeller of an aircraft engine is called.
Option A.	friction   horsepower.	
Option B.	brake   horsepower.	
Option C.	mean effective  horsepower.	
Correct Answer is.	brake   horsepower.	
Explanation.	Brake horsepower=mean horsepower(a theoretical engine value)-friction horsepower.	


Question Number  7	.	Using the following information, determine how many degrees the crankshaft will rotate with both the intake and exhaust valves seated., Intake opens  5 degree?.T.D.C. Exhaust opens 70 degree?.B.D.C. Intake closes 45 degree?.B.D.C Exhaust closes   10 degree A.T.D.C.		
Option A.	610 degree.	
Option B.	290 degree.	
Option C.	245 degree.	
Correct Answer is.	245 degree.	
Explanation.	See CAIP's leaflet E L/1-1 valve timing diagram-the trick is to remember that both valves are closed during parts of the compression and power stroke.