03. Piston Engine: Design and Components Flashcards

1
Q

What is the significance of a cylinder that has more mass

A

More mass = MORE POWER

Pg 54

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2
Q

In a 4-stroke engine, what % of the time is power being produced

A

25%

Pg 54

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3
Q

What is a benefit of multiple cylinder designed engine

A

SMOOTHER POWER DELIVERY

Timed so that a cylinder is always providing power at each phase of the 4 stroke cycle i.e. when there are 4 pistons.

Pg 54

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4
Q

What is the significance of having 4 cylinders on a 4 stroke engine

A

POWER

Power is being delivered by at least 1 cylinder in every stroke

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5
Q

What are the 4 main sorts of piston engines

A
  1. Radial
  2. In-Line
  3. “V”
  4. Horizontally Opposed
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6
Q

Radial Engine

What are 2 benefits in terms of weight and surface area

A
  1. LIGHT
  2. LARGE SURFACE AREA

Large surface area aids cooling

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7
Q

Radial Engine

What is a disadvantage in relation to the size

A

DRAG

Large frontal area increases drag

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8
Q

Radial Engine

What is a disadvantage in terms of oil

A

OIL POOLING

oil can pool in the bottom of the inverted cylinders

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9
Q

Radial Engine

How many cylinders does a typical radial engine have
How can this be increased

A
  1. 9
  2. Additioanl Bank

Add a bank of cylinders behind the other to double cyliner capacity

Pg 56/57

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10
Q

Radial Engine

  1. Oil pooling on startup can cause excessive ____ in the cylinder.
  2. This is known as what
A
  1. PRESSURE
  2. HYDRAULICING

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11
Q

Inline Engine

What are 2 common problems with Inline engine in regards regarding temperature and oil

A
  1. Cooling
  2. Oil Pooling

Cooling is problematic as cylinders in a line rather than all being exposed to airstream like a radial engine
Commonly inverted cylinders, so suffer risk of oil pooling

Pg 58

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12
Q

V Engine

What is a benefit of the V engine specifically over the in-line engine in terms of size, power and how its achieved

A

INCREASED CYLINDERS, REDUCED LENGTH

V engine is effectively 2 in-line engines connected to 1x shared crankshaft
Since the pistons are offset in a V shape, additional piston rods can be connected side by side, with the piston heads being offset from each other
This allows pistons to be connected in-line in a reduced amount of space than a standard inline engine

Pg 59

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13
Q

Horizontal Engine

How are cylinders and pistons arranged and what is significant about the crankshaft

A
  1. Arranged equally, either side of the crankshaft
  2. Share a common crankshaft

Pg 60

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14
Q

What are the 2 core component parts of a cylinder

A
  1. Barrel
  2. Head

Pg 63

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15
Q

What is the purpose of a GASKET

A

Ensures a GAS-TIGHT SEAL

Pg 63

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16
Q

In a liquid cooled engine, what is a GALLERY

A

Incorporated into the casting of the engine
Allows flow of cooling liquid

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17
Q

In an Aero-Engine, how many spark plugs are there typically per cylinder

A

2

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18
Q

What are 3 benefits of having 2 spark plugs per cylinder

A
  1. Redundancy
  2. Even ignition
  3. Faster, even burn

Pg 64

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19
Q

What are HIGH TENSION (HT) leads used for?

A

Connect spark plugs to MAGNETO

Pg 65

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20
Q

What is the top of the piston head called

A

CROWN

Pg 66

21
Q

What is a COMPRESSION RING

A

FITTED AROUND TOP OF PISTON

Prevents gas escaping around the skirt

Pg 67

22
Q

What is the purpose of an OIL CONTROL RING

A

Ensures OIL SPREAD EVENLY

Ensures that the oil is spread evenly around the inner surface of the cylinder

Pg 67

23
Q
  1. What is the purpose of an OIL SCRAPER RING
  2. Where is it fitted
A
  1. Draws excess oil back into the crankcase
  2. Fitted to piston skirt

Pg 67

24
Q

What is the name of the component that connects the piston to the crankshaft

A

CONNECTING ROD

Pg 67

25
Q

What is a GUDGEON PIN

A

Connects ROD to the PISTON

Pg 67

26
Q

What is a BEARING JOURNAL

A

Supports crankshaft in a horizontally opposed engine

Pg 68

27
Q

The CRANK THROW is the distance between what and what

A

Center of crankshaft journal < > Center of crank pin

Pg 68

28
Q

What does the crank throw determine

A

Distance piston moves up and down the cylinder

Pg 68

29
Q

____ are used to counteract ____ of the piston and connecting rod

A
  1. Counterweights
  2. Unbalancing effect

Pg 69

30
Q

What is the typical firing order of a four-cylinder engine

A

1, 3, 4, 2

Pg 69

31
Q

What is the purpose of alternating the cylinder firing order

A

REDUCE STRESS on CRANKSHAFT

Pg 69

32
Q

What 3 items collectively made up form the crank assembly

A
  1. Crankshaft
  2. Connecting Rods
  3. Pistons

Pg 69

33
Q

How is the camshaft driven

A

CAMSHAFT GEAR

Camshaft gear driven by crankshaft

Pg 70

34
Q

How fast does the camshaft rotate compared to the crankshaft

A

ALWAYS HALF THE SPEED

Pg 70

35
Q

The main structural element of an engine is known as the what

A

CRANKCASE

Pg 71

36
Q

What 5 systems are driven by the accessory gearbox

REMEMBER Gears make a Flipping HIPO’s

A
  1. Fuel
  2. Hydraulic
  3. Ignition
  4. Pneumatic
  5. Oil

Pg 72

37
Q

Fuel, oil, ignition, hydraulic and pneumatic systems are all driven by what

A

ACCESSORY GEARBOX

Pg 72

38
Q

Under what method do valves close I.e. what component and force

A

SPRING PRESSURE

Pg 73

39
Q

The INLET or EXHAUST valve is larger than the INLET or EXHAUST valve

A
  1. INLET
  2. EXHAUST

INLET VALVE > exhaust valve

Pg 73

40
Q

What is the purpose of a POPPET VALVE

A

Ensure a GAS-TIGHT SEAL at the port

LINK HERE

Pg 73

41
Q

How are exhaust valves cooled

A

HOLLOW filled with SODIUM

Sodium melts in the heat, moving up and down inside of the valve, transferring heat to the stem

Pg 73

42
Q

What is the name of the hinged lever that applies pressure to the spring holding the valves closed in order to open them

A

ROCKER ARM

Pg 74

43
Q

How are the rocker arms operated

A

PUSH ROD

Pg 74

44
Q

What is the purpose of a tappet

A

ALLOWS FOR THERMAL EXPANSION

Connected between rocker arm and push rod
Tappet allows for termal expansion

Pg 75

45
Q
  1. A large tappet clearance will prevent a valve from ____
  2. A small tappet clearance will prevent a vale from ____
A
  1. Opening Fully
  2. Closing Properlly

REMEMBER
when a door is open there is a large hole/gap
When the door is closed there is no hole/gap
Pg 76

46
Q

What is a benefit of an overhead cam design

A

Elimate the need for push rods

Pg 77

47
Q

The most common design for modern engines it what sort of layout

A

HORIZONTALLY OPPOSED

Summary

48
Q

Aero engines are commonly AIR or WATER cooled.
This saves on ____

A
  1. AIR
  2. WEIGHT

Summary

49
Q

What is the signfiicance of a hydraulic tappet

A

AUTOMATICALLY adjusts the tappet clearance

Summary