farm power engine

1. AE 422
Agricultural Power and
Its Sources
INTERNAL
COMBUSTION ENGINE

2. Scores and Attendance
STUDENT
Attendance
Total
Absent
Today
Quiz
Previous Total
Score
Acay, Noreen Grace
30
Barbo, Herloid Cesar
30
Bayan, Charlie
1
Borda, Renaldo
14
Borero, Saidamen
31
Duran, Iza Roseline
16
Eslao, John Fernan
30
Flores, Precious
18
Gallera, Jose Bernie
9
Percentage

3. Scores and Attendance
STUDENT
Attendance
Total
Absent
Today
Quiz
Previous Total
Score
Gomez, Franklin
13
Lampon, Melvin
23
Mateo, Abigail
12
Omega, Julius
26
Paulino, Adrian
28
Pino, Fatima
27
Reponte, Maricel
15
Salik, Naila
26
Samillano, Denard
20
Travilla, Charles
20
Percentage

4. Scores and Attendance
STUDENT
Attendance
Total
Absent
Today
Quiz
Previous Total
Score
Pavo, June Carlo
3
Florido, Florievic
23
Sasi, Precious Anne
31
Nadala, Sonie
27
Garcia, Jacklyn
A
25
Percentage

5. Short Quiz (50 pts)
1) Define Engine (10)
2) What are the two types of Heat Engine (4)
3) Enumerate the Conditions for ICE to achieve maximum
efficiency as stated in Beau de Rochas Principle (10)

6. Figure 3.2.1
4.) Identify the
following engine
based on position
and number of
cylinder (12 pts)

7. Figure 3.1.2
5) Identify the Parts of an
Enginer (14 pts).
b
c
a
e
j
d
k
f
i
f
l
g
h

8. Pass your Papers

9. Answers
Define Engine.
An engine is a mechanical device used to
convert the heat energy of fuel produced
by combustion into mechanical energy
Two types of engine
External Combustion Engine
● Internal Combustion Engine
●

10. Answers
Define Engine.
An engine is a mechanical device used to
convert the heat energy of fuel produced
by combustion into mechanical energy
Two types of engine
External Combustion Engine
● Internal Combustion Engine
●

11. Answers
Conditions for ICE to achieve maximum efficiency:
1.
The largest possible cylinder volume with the
minimum boundary surface
2.
The largest possible working speed
3.
The greatest possible expansion ratio
4.
The greatest possible pressure at the beginning of
expansion

12. Answers
Position and Number of cylinders of reciprocating engines
Single cylinder
In-line
V-engine
Opposed cylinder engine
Opposed piston engine
W-engine
Radial engine

13. Answers

14. LAWS OF THERMODYNAMICS
1ST LAW OF THERMODYNAMICS
•
•
Law of the conversion of energy
States that “When heat energy is transformed into
mechanical energy, the work done is equivalent to
the quantity of heat involved.”
2nd LAW OF THERMODYNAMICS
•
States that “Heat will, of itself pass from a hot to a
cold substance, but external work is required to
transfer heat from a cold substance to a hot
substance.”

15. 2 ways in which combustion takes
place in ICE
1.
2.
By rapid explosion of mixture within
cylinder when it is ignited by a spark
(constant-volume process)
By relatively slow burning as the fuel is
injected into highly compressed, heated
air (constant –pressure process)

16. ICE PRINCIPLES
ASSUMPTIONS:
•
Air pressure during intake stroke (AB) is atmospheric
•
Compression and expansion are adiabatic process
•
Specific heat remains constant through out the cycle

17. CYCLE OF OPERATIONS
1
2
ENGINE
CYCLE
4
3

18. 4-STROKE CYCLE PRINCIPLES
1.
Intake Stroke
•.
•.
•.
Begins with the piston moving down
Intake valve opens and a fuel mixture
(in SI) or air alone (in CI) enters the
cylinder
At the completion of this stroke, the
piston is at the bottom of the
cylinder and both valves are closed.

19. 4-STROKE CYCLE PRINCIPLES
2. Compression Stroke
➢
➢
➢
When the piston reaches at the bottom
of the cylinder on the intake stroke it
starts upward
Both valves are closed
At the top of this stroke, the fuel
mixture is compressed tightly

20. 4-STROKE CYCLE PRINCIPLES
3.
4.
Power Stroke
•.
A spark from the spark plug ignites the mixture
•.
Results to rapid expansion of the burning mixture
•.
Piston is pushed downward
•.
Still, both valves are tightly closed
Exhaust Stroke
•.
When the piston reaches the bottom, it starts moving
upward
•.
As the piston moves up, the exhaust valve opens and
the exhaust fumes are pushed out of the cylinder
•.
Exhaust stroke is completed with the piston at TDC
•.
Cycle is repeated

21. 2-STROKE CYCLE PRINCIPLES
Intake & Exhaust Strokes
ü
Uncovers the intake and exhaust ports as the
piston nears the bottom of its stroke
ü
Because air-fuel mixture (SI) or air (CI) in the
crankcase is under pressure, it rushes through
a passage to the intake port and enters the
cylinder
ü
This incoming fuel mixture (SI) or air (CI)
pushes the exhaust gases out of the cylinder
ü
Therefore, intake and exhaust functions occur
with very little movement of the piston

22. 2-STROKE CYCLE PRINCIPLES
•
Compression Stroke
ü
ü
ü
the cylinder now is filled with the fuel
mixture (SI) or air (CI)
Pistons moves upward, closes the
intake and exhaust ports and
compresses the fuel mixture
At the same time, new supply of air
and fuel rushes in the crankcase

23. 2-STROKE CYCLE PRINCIPLES
•
Power Stroke
ü
At or near TDC, the spark plug fires the mixture
(SI) or fuel is injection into the cylinder (CI)
ü
The burning and expanding gases drive the piston
downward
ü
This same downward movement puts pressure on
the new air-fuel mixture in the crankcase pushing
it into the cylinder (which in turn pushes the
exhaust gases out of the cylinder )
ü
Thus, the engine completes its cycle of intake,
compression, power and exhaust with only two
strokes of the piston.

24. 2-STROKE CYCLE PRINCIPLES
Operation of 2-stroke spark ignition engine

26. ADVANTAGE OF 2-STROKE
OVER 4-STROKE
Lighter weight (no mechanical
valves, eliminating the camshaft to
operate the valves)
Lubricating oil is mixed with the fuel
and there is no sump to hold engine
oil allowing engine to operate in any
position even upside down.

27. THEORY OF OPERATION
•
•
•
•
•
The function of all internal combustion engines is to
convert fuel (chemical energy) to power.
Accomplished by burning a fuel in a closed chamber
and using the increase in temperature within the
closed chamber to cause a rise in pressure
Pressure produces a force on the head of the piston
causing it to move
The linear movement of the piston is converted to
rotary motion (at the crankshaft)
Rotary motion is more useful than linear movement

28. EIGHT (8) REQUIREMENTS FOR
OPERATION
1) Air (oxygen) is drawn into the engine
cylinder.
2) A quantity of fuel is introduced into the
engine.
3) The air and the fuel are mixed.
4) The fuel–air mixture is compressed.

29. EIGHT (8) REQUIREMENTS FOR
OPERATION
5) The fuel–air mixture is ignited by the spark plug in
gasoline engines or by the heat of compression in
diesel engines.
6) The burning of the fuel–air mixture causes a rapid
pressure increase in the cylinder, which acts against
the piston, producing a force on the piston.
7) The use of a connecting rod and a crankshaft converts
the linear movement of the piston to rotary motion.
8) The force on the piston is converted to torque on the
crankshaft.

30. Reminders:
●
Next Module: Engine Operating Characteristics
–
References
●
●
Goering, Carroll E., and Alan C. Hansen. 2004. Practical Engine Cycles and
Timing. Chapter 2- 3 in Engine and Tractor Power, 4th edition, St. Joseph,
Michigan: ASAE. © American Society of Agricultural Engineers.
Roth, Alfred C. Small Engines