Piston Engine Design/Components Flashcards
Classification of engine
Number of cylinders
Arrangement
Method of cooling
Fuel type
Liquid Cooling
Preferred method on A/C
Weight penalty
Maintenance issues
Radial Engine
Cylinders arranged in circle around crankshaft
7-9 cylinders “leapfrog” 1,3,5,7,2,4,6 etc
Banks of arrangement of cylinders
- Hydraulicing - oil build up in inverted cylinder cause over stress pressure (*2 turn of rev of crankshaft)
In Line Engine
Horizontal to reduce frontal load
- difficult to cool
- usually limited to 6 cylinders
V Engine
Two in line engines set at angle
+ increase no of cylinder for same length
Horizontally Opposed Engine
Short/rigid/most common design
Air cooled
Barrel and Head
Head: Aluminium
Bottom: cast steel
Bolted together for gas tight seal
Cooling fins
What is cast
Melting of metal and pouring to make a mould
Spark Plugs
X2 in cylinder for redundancy/increased safety
Smoother/quicker/more efficient
Connected to magnetos
Piston
Made of Aluminium
- Compression rings
- Connecting rods
- Gudgeon pin
Crankshaft
Cast Steel
Heaviest component
Converts Linear motion to rotary motion
Camshaft
Cast steel
Operate valves via push rods
Run parallel to crankshaft
Rotates at half speed of crankshaft
Crankcase
Main structural element of engine
Light strong alloy magnesium
Provide mounting points
Crankshaft and camshaft located in crankcase
Valves Operation
Opened by camshaft
Close under spring pressure
X 2 for preventing bounce/redundancy/smoothness
Inlet vales properties
Stem - Smaller
Head - Bigger
Exhaust Valve properties
Stem - Bigger
Head - Smaller
Hollowed and filled with sodium for heating
Excessive valve clearance
Open too late and close early
Insufficient valve clearance
Make contact early/close late
What does tapper do
Ensure valve close at all temps
Too much clearance valve will open late and close early
Too little clearance valve will open early and close late
Reduction in performance
Valve Gear
Collective name for pushrods/rockers
Valves Made Of?
Steel Alloy
Gudgeon Pin
Passes through the small end and the piston
