Module 4: Internal Combustion Engines Flashcards
mechanical device used to convert the heat energy of fuel produced by combustion into mechanical energy.
internal combustion engine
main application of ICE
used as prime movers for mobile and field equipment such as tractors, pumps, sprayers, harvesters and threshers
other applications of ICE
- fishing boats to increase fishermen’s mobility
- places where elec motors cannot be used
parts of ICE converts reciprocating linear motion into?
rotational motion
movement of the piston from TDC to BDC or vice versa
stroke
highest position attained by the piston when it goes up
top dead center (TDC)
lowest position attained by the piston when it goes down
bottom dead center
engine classification based on no. of piston movement needed for a cycle
1) 4-stroke
2) 2-stroke
engine classification based on manner of igniting the fuel
- spark ignition
- compression ignition
in a 4-stroke cycle engine, each stroke corresponds to what?
each corresponds to an event in the cycle
in a 2-stroker cycle engine, power and exhaust happens in one stroke and intake and compression happens on the other
true or false
false; power, exhaust, and intake happens in one stroke
in a spark-ignition engine, what is used to ignite the compressed air-fuel mixture?
spark plug
spark-ignition engine
spark occurrence is timed when
before or at TDC
spark-ignition engine
what type of fuel is used
gasoline
spark-ignition engine
air and fuel is mixed and metered by the _________ before the intake event
carburetor
engine that uses heat of compressed air to ignite the fuel
compression-ignition engine
in a compression-ignition engine, air is compressed to a very high degree
true or false
true
during intake in a compression-ignition engine, air and fuel is taken in
true or false
false; only air is taken in, fuel is injected before end of compression
compression-ignition engine
what type of fuel is used
diesel
in a compression-ignition engine, fuel metering is done by?
fuel injection system
series of events occurring one after the other in a definite sequence and repeats itself after the last event has occurred.
cycle
four events comprising an engine cycle
- intake
- compression
- power
- exhaust
cycle of operation (explain the steps)
air-fuel mixture or air enters combustion chamber —> it is compressed inside —> spark is produced or fuel is injected and the mixture is ignited resulting to a very rapid expansion of the burning mixture —> constitutes the power of the engine —> burned gases are removed —> cycle is repeated
basic engine terminology
- bore
- stroke
- piston displacement
- clearance volume
- total volume
- compression ratio
engine specifications
- engine type
- engine dimensions
- output
- capacities
- auxiliary systems
diameter of the cylinder, inches or mm
bore (D)
length of travel of the piston from TDC to BDC, inches or mm
stroke (L)
volume displace by the piston as it moves from BDC to TDC, cubic inches, cubic mm, or cubic cm
piston displacement
volume of the cylinder when the piston is at TDC
clearance volume
volume of the cylinder when the piston is at BDC
total volume
how do you get the total volume?
add piston displacement and clearance volume
ratio of total volume over clearance volume
compression ratio
serve as a good source of power to perform diff kinds of farm operations
ICE
devices that generate work using the products of combustion as the working fluid rather thanas a heat transfer medium
ICE
commonly, diesel engines are used in what type of tractor to perform specific farm operations like in crop establishment processes?
two-wheel tractors
a diesel engine is heavier and stronger than a gasoline engine of an equal hp because?
its materials are used to withstand the greater dynamic forces from higher combustion pressures present in the engine
higher compression ratio results to greater combustion pressure
true or false
true
measure of how much the engine compresses the gas in the cylinder
compression ratio
lower ignition temp of gasoline will cause ignition at a CR of less than __:1
10
in diesel engines, CR ranges from 14:1 to as high as 24:1
true or false
true
higher CR of diesel engine is made possible because?
only air is compressed and then fuel is injected
