Engines - 4-Stroke, 2-Stroke, Camshaft, Cylinder Head, Mechanical Components, Compression Ratio, Engine Block Flashcards
List 6 components of a cylinder
Inlet valve
Exhaust valve
Combustion chamber
Piston
Connecting rod
Crankshaft
How many revolutions of the crankshaft is a stroke in a 4-stroke engine?
Half a revolution
What are the 4 strokes of a 4-stroke process? (simple and fancy ways)
Suck
Squeeze
Bang
Blow
Intake
Compression
Power
Exhaust
How many power strokes does a 4-stroke engine cylinder have per crankshaft revolution?
1 per 2 crankshaft revolutions
What do 2-Stroke engines have instead of intake and exhaust valves?
Intake, exhaust and transfer ports
How are the moving parts of a 2 stroke engine lubricated? Why?
By the fuel
Because the crankcase is used in the 2-stroke process
In 2 strokes of a 2-stroke engine, how many times does the piston move up and down each cycle?
Up once, down once
List 3 things that occur in a 2-stroke engine during the first stroke
The exhaust gases flow out of the cylinder
The fuel/air mixture is ignited
The transfer port takes the fuel/air mixture from the crankcase to the combustion chamber
List 4 things that occur in a 2-stroke engine during the second stroke
The reed valve opens and fuel/air goes into the crankcase
The fuel/air in the combustion chamber is compressed
The last residue of exhaust gas flows out of the combustion chamber
In the first stroke of a 2-stroke engine, why does the fuel/air mixture go from the crankcase to the combustion chamber?
The piston moves down, creating pressure in the crankcase as the exhaust fumes exit the combustion chamber
What is the function of a reed valve in a 2-stroke engine?
Ensure that that fuel/air mixture doesn’t flow back into the inlet port
What is another term, sometimes used for the combustion chamber?
The cylinder
In the second stroke of a 2-stroke process, how is a partial vacuum created in the crankcase? (which sucks fuel/air in)
The underside of the piston opens the crankcase up as it closes the combustion chamber, unlike in a 4-stroke engine
How often is the fuel/air mixture ignited in a 2-stroke engine?
Once per revolution (every time the piston is at top dead centre (TDC)
What is the function of the camshaft?
The operation of the valves
What could you compare the shape of a cam to?
An egg
Name the 2 metals that camshafts can be made of
Forged steel, cast iron
List the 3 types of camshaft
Overhead camshaft
Double overhead camshaft
Camshaft with overhead valves
Out of the 3 types of camshaft, which one uses a different camshaft for each valve? (The other 2 use 1 for both)
Double overhead camshaft
Out of the 3 types of camshaft, which one is placed below the piston, connected by a pushrod to the valves which are above?
Camshaft with overhead valves
Name 5 components of a camshaft with overhead valves, in order from bottom to top
Camshaft
Tappets
Pushrod
Rocker
Valves
The intake cam shape can be changed using the buttons. What 2 things will result from a more acute/sharp intake cam shape?
The inlet valve will open later
The inlet valve will close earlier