This document contains class records and notes from an agricultural power and engine components course. It includes a class attendance record, the results of short quizzes on engine components and cycles, and explanations of key engine parts like the cylinder block and head, valves, pistons, crankshafts, and bearings. It also summarizes the timing of practical four-stroke and two-stroke engine cycles, including valve timing, ignition timing, injection timing, firing intervals, and firing orders. The document provides an overview of internal combustion engine design and operation.

1. AE 422
Agricultural Power and
Its Sources
ENGINE
COMPONENTS

2. Class Record
Attendance
Names
Acay, Nollen Grace
Barbo,
Bayan
Borda
Borero
Duran
Eslao
Flores
Gallera
Gomez,
Lampon
Mateo
Omega
Paulino
Pino
Reponte
Salik
Samillano
Travilla
Pavo
Florido
Sasi
Nadala
Garcia
11-18-13
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
11-25-13
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
A
P
P
P
P
12/02/13
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
Quize
12/09/13 Absences
Q1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
Q2
30
30
30
14
31
16
30
18
9
13
23
12
26
28 27
15
26
20
20
3
23
31
27
25 -
Q3
46
50
41
66
45
57
43
46
57
57
48
40
42
27
48
33
22
36
30
39
55
42
25
30
14
22
17
23
22
27
20
28
25
15
26
16
20
20
29
24
10
20
28
14
26
15

3. Short Quiz (50 pts)
1. What is the piston speed of an engine having a
revolution of 2100 revolution per minute and a stroke
of 21 cm (15 pts)
2. Given a four-cylinder Otto cycle engine with a 70mm bore, 135-mm stroke, and a clearance volume
of 0.121 L . (Assume n = 1.4).
A) What is the total engine displacement?.
B) What is the compression ratio of the engine?
C) What is the theoretical Cycle efficiency?
(25 pts)

4. Short Quiz (50 pts)
1. The volume of gas in the cylinder when the
piston is at head dead center (HDC) is called
_________. (2 pts)
a. Total Volume
b. Clearance Volume
c. Displacement Volume
d. Head Dead Volume

5. Short Quiz (50 pts)
2. What is the volume fo
the air-fuel mixture in the
figure (2 pts)
a. Total Volume
b. Displacement Volume
c. Clearance Volume
d. Exhaust Volume

6. Short Quiz (50 pts)
3. At point 0 the intake
valve is ___________ .
(2 pts)
a. Open
b. Closed
c. Semi Open
d. Semi Closed

7. Short Quiz (50 pts)
4. The process that occurs
between point 1 and 2 is
______________. (2 pts)
a. polytropic compression stroke
b. polytropic expansion stroke
c. Power stroke
d. Exhaust Stroke

8. Short Quiz (50 pts)
5. It is the theoritical cycle for
spark ignition system?
a. Diesel Cycle
b. Carnot Cycle
c. Gasoline Cycle
d. Otto Cycle

9. ANSWERS
1. What is the piston speed of an engine having a
revolution of 2100 revolution per minute and a stroke
of 21 cm (15 pts)
S =2LN
S =2∗21∗2100
S =88200 cm/ min
S =1470 cm/ sec

10. ANSWERS
2. Given a four-cylinder Otto cycle engine with a 70mm. bore, 135-mm stroke, and a clearance volume
of 0.121 L (7.386 in.3). (Assume n = 1.4).
A) What is the total engine displacement?.
V e=nV d
π D2
V d=
L
4
2
π7
V d=
13.5
4
V d =519.5 cc
V e =4∗519.5
V e =2078 cc

11. ANSWERS
2. Given a four-cylinder Otto cycle engine with a 70mm. bore, 135-mm stroke, and a clearance volume
of 0.121 L (7.386 in.3). (Assume n = 1.4).
B) What is the compression ratio of the engine?
V T V D +V C
CR= =
VC VC
V T 519.5+121
CR= =
V C 121
CR=5.294
Probably a Gasoline Engine

12. ANSWERS
2. Given a four-cylinder Otto cycle engine with a 70mm. bore, 135-mm stroke, and a clearance volume
of 0.121 L (7.386 in.3). (Assume n = 1.4).
C) What is the theoretical Cycle efficiency?
1
Otto cycle efficiency=1− n−1
r
1
Otto cycle efficiency=1−
1.4−1
5.294
Otto cycle efficiency=0.4866
Probably
Not Yet
INVENTED

13. ANSWERS
1. The volume of gas in the cylinder when the
piston is at head dead center (HDC) is called
_________. (2 pts)
a. Total Volume
b. Clearance Volume
c. Displacement Volume
d. Head Dead Volume

14. ANSWERS
2. What is the volume fo
the air-fuel mixture in the
figure (2 pts)
a. Total Volume
b. Displacement Volume
c. Clearance Volume
d. Exhaust Volume

15. ANSWERS
3. At point 0 the intake
valve is ___________ .
(2 pts)
a. Open
b. Closed
c. Semi Open
d. Semi Closed

16. ANSWERS
4. The process that occurs
between point 1 and 2 is
______________. (2 pts)
a. polytropic compression
stroke
b. polytropic expansion stroke
c. Power stroke
d. Exhaust Stroke

17. ANSWERS
5. It is the theoritical cycle for
spark ignition system?
a. Diesel Cycle
b. Carnot Cycle
c. Gasoline Cycle
d. Otto Cycle

18. A cutaway view of an internal combustion
engine. (Courtesy of Deere & Company.)

19. THE CYLINDER BLOCK
●
●
The cylinder block is the
backbone of the engine. It
supports most of the other
engine parts and holds them in
proper relationship to each
other.
The block also may act as part of
the framework of some tractors
and support the front wheels
(Figure 3.2).

20. Types of Cylinder Liner
●
Enbloc – cylinders are cast directly into the block
●
Dry liner – the liner does not come into contact with the engine coolant
●
Wet sleeve – serves as the only wall between the piston and coolant.

21. THE CYLINDER HEAD
●
The open ends are sealed by means of a cylinder head
In addition to
sealing the
combustion
chambers, the
head contains the
valves and
passages, or
ports, to the
intake and
exhaust
manifolds

22. THE CYLINDER HEAD
●
●
●
A special cylinder head gasket is
used between the head and
block .
Typically, such gaskets are made
of asbestos and include metallic
rings around each cylinder to aid
in sealing in combustion gases.
The head is fastened to the block
with high-strength head bolts,
which must be tightened down
gradually and uniformly to
ensure good sealing.

23. THE VALVE TRAIN
●
●
The valves control the
inflow of unburn fuel
and the outflow of the
burned fuel.
The valve actuation
begins with the
camshaft, to the tappet,
push rod and soon.

24. THE VALVE SEATING

25. PISTON AND CONNECTING ROD ASSEMBLIES

26. TYPES OF PISTON RINGS

27. CRANKSHAFTS, FLYWHEELS AND BALANCERS

28. BEARINGS

29. PRACTICAL ENGINE CYCLES ANG TIMING
In either type of
engine, it is essential
that certain events
are timed correctly
with the movement
of the piston, or the
engine will not run.

30. PRACTICAL ENGINE CYCLES ANG TIMING
FOUR-STROKE-CYCLE ENGINES
●
Valve Timing
–
Cam lobes to camshaft lift
the tappets. Each rocker arm
translates upward movement
of a tappet and push rod into
downward movement of a
valve, thereby compressing
the valve spring and opening
the valve.

31. PRACTICAL ENGINE CYCLES ANG TIMING
FOUR-STROKE-CYCLE ENGINES
●
Ignition Timing
–
Ideally, nearly all of the fuel energy
would be released when the piston
was at HDC and ready to begin the
power stroke.
–
Spark advance refers to the
number of crankshaft degrees
before HDC at which the spark
plug fires.

32. PRACTICAL ENGINE CYCLES ANG TIMING
FOUR-STROKE-CYCLE ENGINES
●
Injection Timing
–
Injector nozzles are used to inject fuel into
diesel engines. The fuel does not ignite
instantaneously when it is injected into the
hot combustion chamber.
–
ignition delay, injection must start before
HDC if a high percentage of the fuel is to be
consumed before the piston is well past
HDC. Timing of the start of injection is
selected to optimize performance of each
model of engine, but is typically in the range
from 15° to 30° before HDC.

33. PRACTICAL ENGINE CYCLES ANG TIMING
FOUR-STROKE-CYCLE ENGINES
●
Firing Intervals
–
The firing intervals refer to the number
of degrees of crankshaft rotation between
successive power strokes.
–
Cylinders must be numbered in a
multicylinder engine for purposes of
identification. Numbering begins at the
front of the engine.

34. PRACTICAL ENGINE CYCLES ANG TIMING
FOUR-STROKE-CYCLE ENGINES
●
Firing Interval for a 4 cylinder

35. PRACTICAL ENGINE CYCLES ANG TIMING
FOUR-STROKE-CYCLE ENGINES
●
Firing Orders
–
There are two possible firing
orders for the engine of 4
cylinders. The firing order given
in the figure is as follows:
1-3-4-2
or
1-2-4–3
Most Common for 6 cylinder
1-5-3-6-2-4

36. PRACTICAL ENGINE CYCLES ANG TIMING
TWO-STROKE-CYCLE ENGINES
Two-Cycle Spark-Ignition Engines
●
–
While the piston is moving
upward on a compression
stroke, a vacuum is created in
the crankcase, and the check
valve opens to admit the air fuel
mixture. The check valve
closes, and the mixture in the
crankcase is compressed as
the piston moves downward on
the power stroke.

37. PRACTICAL ENGINE CYCLES ANG TIMING
TWO-STROKE-CYCLE ENGINES
Two-Cycle Spark-Ignition Engines
●
–
Two-cycle engines have the
advantage of a high power-tosize ratio. By producing a
power stroke during every
revolution of the crankshaft, a
two-cycle engine can produce
much more power than a
four-stroke-cycle engine of the
same size.

38. PRACTICAL ENGINE CYCLES ANG TIMING
TWO-STROKE-CYCLE ENGINES
●
Timing in the Two-Cycle Engine
●
–
There is no valve train in
two-cycle spark-ignition
engines because the moving
piston covers and uncovers the
intake and exhaust ports in the
cylinder wall and thus the timing
is set when the engine is built.
●
The exhaust valve begins to
open at 97.5° before CDC,
begins closing at 43° after CDC,
and is fully closed at 63° after
CDC.
The intake port is uncovered
after the exhaust valve is
closing on the downstroke and
before the exhaust valve closes
on the upstroke. Thus,
approximately 55% of the cycle
is used for compression and
power; the remaining 45% is
used for scavenging exhaust
gases and intake of fresh air.

39. PRACTICAL ENGINE CYCLES ANG TIMING
TWO-STROKE-CYCLE ENGINES
●
●
●
●
Timing in the Two-Cycle Engine
The spark plug is timed to fire
approximately 6° to 8° before HDC
in two-cycle spark-ignition engines.
Typically, these engines run at
full speed when doing work, and no
ignition advance system is needed.
●
Diesel injection begins at
23.5° before HDC in a typical
two-cycle diesel engine and
ends at 6° before HDC when
the engine is running at full
load. Thus, injection ends
much earlier than in fourcycle diesels, where injection
can continue well past HDC at
full load.
Extending fuel injection into the
power stroke of two-cycle diesel
engines would not be
satisfactory

40. PRACTICAL ENGINE CYCLES ANG TIMING
TWO-STROKE-CYCLE ENGINES
●
Firing Intervals and Orders
●
●
Firing Intervals and Orders
The firing interval of a
two-cycle engine is half
that of a comparable
four-cycle engine as
indicated by Equation

41. Reminders:
●
First Long Exam Next meeting
●
Make up for absenses on Exam till Thursdays.
●
Next Module: Engine Performance
–
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 Engine
●
Philippine Agricultural Engineering Standards