Construction and Principles 1 Flashcards
Four Stroke Otto Cycle
Induction Compression Power Exhaust (Suck, Squeeze, Bang, Blow)
Induction Stroke
Air and fuel mixture is drawn into the cylinder.
The pressure differential draws the fuel-air mix in.
Compression Stroke
Both valves are closed and the mixture is squeezed.
The mixture heats and pressure increases
Power Stroke
Mixture is ignited and expands.
Force of expansion pushes the piston down.
Exhaust Stroke
Waste products are expelled
Crank Case
Main structural part of the engine
Contains mounting point for the barrels, crankshaft, camshaft and accessory parts
Crankshaft
Component which converts linear motion into rotary motion
The stroke is ______ the throw
Double
The stroke is the distance end to end
Connecting Rods
Connect pistons to the crankshaft
Usually made of steel
What connects a piston to the little end of a connecting rod?
Gudgeon Pin (wrist pin)
Barrel
Consists of cylinder and cylinder head
Poppet Valve
Control inlet and exhaust flow
The inlet is normally larger to maximise the charge draw
Why are exhaust valves often filled with sodium?
To dissipate the heat of the exhaust gases
At what speed does the camshaft rotate?
At half the speed of the crankshaft
What is a stroke?
Distance between TDC and BDC
Clearance Volume
Volume above the piston at TDC that the mixture is compressed into
Swept Volume
Total Volume - Clearance Volume
Compression Ratio
Swept Volume + Clearance Volume (Total Volume)
——————————————————————
Clearance Volume
Firing Order
1: Power
2: Exhaust
3: Compression
4: Induction
1,3,4,2
Or
1,4,3,2
One Horse Power
Movement of 330lb through 100ft in 1 minute
BHP
Torque x RPM
IHP (Indicated Horse Power)
Plane
—————
33000
P= Indicated Mean Effective Pressure L= Length of Stroke A= Area of Piston Crown N= Number of Power Strokes/Minute E= Number of Cycles
BHP
IHP-FHP
Power Output is Affected By:
Air Density
Exhaust Back Pressure
Mixture Ratio
