Powerplant Flashcards
What is the total amount of mixture drawn into a cylinder called?
The charge
Top dead centre to bottom dead centre is described by what phrase or term?
Stroke
What are the four strokes called of a 4 stroke engine?
Induction
compression
power
exhaust
Ineffective crank angle can be described as?
The top 90 degrees and the bottom 90 degrees of the crank angle as it only moves a small amount
Describe inlet valve lead
Inlet valve opens early to increase the speed of exhaust when the ineffective crank angle is at play
Why would you increase the number of cylinders
To increase the mass of charge combusted
Radial engines have the potential of multiple banks
It is an odd number
the core of the crank can be described as the
journal
The stroke or height is
Throw
Cam lobe does what and can be found where
On the cam shaft rotating to actuate the push rods up and down
A tap it and adjusting nuts are used to adjust what
The spacing between the rocker arm and the valve stem
How does the starter motor connect to the crank shaft?
The starter overrun clutch and flywheel gear
When operating the starter a light should come on, after how long should you turn the starter off
Thirty seconds
A magneto has two circuits or windings what are they called
Primary windings and secondry windings. these are either side of a transformer, the secondary windings deliver power to the spark plugs. There is a engine controlled spinning magnet to generate the electron movement and a cam to activate a breaker
When Magneto rotation is slow for example during starting, there may not be sufficient high tension voltage. Name three methods spark augmentation
Impulse coupling
low tension booster
high tension booster
How would you describe a spark plug with the gap blocked
fouled
AVGAS burns at around (speed)
18-24m/s
AVGAS burns at around 18-24m/s and produces a ___________ rise in cylinder pressure
predictable
AVGAS also displays good __________ properties allowing it to resist detonation
anti-knock
AVGAS contains: ??% Carbon and ??% Hydrogen
85% Carbon
15% Hydrogen
what octane rating is avgas 100 and
avgas 100l l
100
MOGAS is not ‘commonly’ used because…
Prone to detonation
Not certified
Unknown water content
Fuel sample should have which 4 properties
The sample must be:
Clear and bright
Free of sediment
No entrained water
Max water content 30ppm.
The Principle causes of Pre-Ignition are:-
Hot spot within the cylinder – typically Carbon deposits on a valve
Ignition malfunction – damaged spark plug
High Cylinder temperatures (CHT)
Pre-ignition can be more destructive than detonation and should be avoided or detected before long term damage can take effect.
The principal causes of detonation are:-
- Fuel with poor anti-knock properties
- Incorrect (excessively weak) mixture
- Anything that might unduly raise temperature or pressure, (e.g Low RPM with high Manifold Absolute Pressure – more later)
- High engine temperature.
Chemically correct mixture ratio would be
15:1
Rich mixture ratio would be
8:1
Lean mixture ratio would be
20:1
Fuel injection occurs before or after the throttle valve
Fuel injection occurs after the throttle valve or in the cylinder head.
Delete this card
Byeeee
