Module 1 and 2 0engines Flashcards
what is detonation
uncontrolled explosion of fuel/air mixture
how calculate compression ratio
Total volume of cylinder
____________________
combustion chamber volume
where is MAP taken
between the carburetor and throttle
what is pre-ignition
premature ignition of fuel/air mixture
what is a heat engine
convert heat energy by combustion
what is the aprox thermal-efficiency of an internal combustion ?
30% heat
example of internal engine and external engine
internal =opposed 4 stroke
external =steam engine
pistons rings ac engines made of ?
- gray cast iron
- chrome plated
3 types of rings
- compression
- oil control
- oil wiper (scraper)
Compression rings have 3 types of cross
- Rectangular
- tapered
- wedge
must common type of ring joint?
butt
to compensate for uneven expansion heat the piston is
cam ground -larger diameter
undersides of pistons are frequently finned primarily ?
to aid cooling
pistons are machined from what type of alloy?
aluminum
pistons are classified by head design
- flat
- cupped
- dommed
the area between the pistons ring groves is called
Ring land
purpose of the a piston ring
- provide seal
- prevent excessive oil
- conduct heat
types of bearings commonly used
- plain
- roller
- ball
how you clean pack and inspect an anti-friction roller bearing
- clean in solvent
- air dry (don’t spin)
- 10 power magnifying glass
if exhaust valve open to early what happen ?
loss power
what is a valve overlap?
number of degrees during intake valve and exhaust valves are open
what type of engine would you expect to see a camshaft in?
opposed-in line-v type
if intake valve opens to early what symptom will occur ?
back fire in the induction system
what is the fit of the piston pin to the piston boss
palm push fit
an engine cylinder is a two piece construction consisting of ?
- cylinder head
- barrel
when referring to the cylinder numbers on an opposed engine from what direction does one look
-always from the back
what is the purpose of a piston
-draw air
-transmit force from the cylinder
-manage the pressure in the cylinder and transmit the
force of combustion to the connecting rod
knuckle pin is used to ?
connect articulating rods to the master rods
what color is used to identify a nitrate cylinder
-blue
what is the purpose of the choke bore cylinder
compensate for the uneven expansion cause by heat
what precaution is necessary for metal sodium filled valves ?
sodium is dangerous material that burns violently when exposed to air
why poppet valve
pops open and close
when the exhaust valve open and close in the 4 cycle
open before TDC on the power stroke and closes after TDC on the intake stroke
where in the induction system is map measured
downstream of carburetor after the throttle valve
will MAP ever be higher than the ambient pressure?
only in a turbo charged
what does the red arc indicate on the RPM gauge
max power RPM
what kind of ring can withstand higher temp
chrome plated ring
what are the piston pin made of
Nickel steel alloy
what kind of pin is used in the lycoming O-320A23
full floating
what is the most common pin retainer
piston pin plug
where is the valve clearance measured
between the rocker arm and valve tip
what type of engine uses a cam ring
radial
why some engine have gear reduction
to keep the speed of the propeller to achieve max efficiency
oil pressure is calculate in what unit
PSI ( pounds per square inch)
what is the valve overlap
period when the intake valve and exhaust valve are both open
when is the valve clearance set and how is it adjusted on the O320-A23 engine
cold clearance by changing the length of the push rod
how manu revolutions to complete all 4 stokes
two
4 strokes of the engine
- intake
- compression
- power
- exhaust
the crankshaft change linear motion into
rotational motion
dynamic damper is for the purpose of ?
dampening torsional vibrations
main part of crankshaft
- main journals
- crank pins
- crank cheek
the crankcase supports the crankshaft by
main journals
aircraft piston engines are classified
- air cooled and liquid cooled
- internal or external combustion
- by cylinder arrange =V type, opposed , in line, radial
- naturally aspired or turbocharger
- Otto cycle or diesel
- 4 stroke or 2 stroke
- carburetor or fuel injector
engine noted as a freedom vibrations
horizontally opposed
what are the 5 events on a cycle
- intake
- compression
- ignition
- power
- exhaust
least friction bearing
ball bearing
general manufactures required
- efficiency
- economy
- reliability
- durability
what makes diesel ideal for an aircraft power plant
low RPM and high torque
diesel advantages
- high durability
- better efficiency
- time to be overhaul
difference between otto and diesel
- compression ratio is higher
- diesel has not spark plug
which gauge is important to monitor during the engine start
-oil pressure
will the CHT gauge increase with a reach mixture ?
no, it will decrease
what does the EGT gauge measured
indicates exhaust gas temp used to set mixture
how is the IHP calculated ?
plank /33.000 horsepower
IHP =
FHP=
BHP=
IMEP=
indicate horse power
friction horse power
brake horse power
indicated mean effective pressure
