Agricultural engineering

Marzuqi Salleh, UiTM Perlis

FINAL QUESTION AND ANSWER

(COLLECTION)
AGRICULTURAL ENGINEERING

AGRICULTURAL ENGINEERING CONFIDENTIAL


PREPARED BY: MARZUQI BIN MOHD SALLH

Brief the function of the following components in the system given and explain their roles.
Water cooling system
i) water pump -heart of the cooling system, circulates the coolant through the system
iii) thermostat -to provide automatic control of engine temperature at the correct level in order
to get the best performance.
v) radiator-reservoir and heat exchanger for coolant
iv) by-pass -allow water to distribute in all part

Lubricating system
i) oil strainer-Store up dirty oil lubricating to remove to drain plug
ii) oil sump-Made of iron casting, Seals the crankcase at the bottom, Functions as a reservoir for
the lubricating oil
vi) oil pan - act as reservoir for engine oil
v) galleries-the passage through which the oil pumped
iv) pressure guage- to tell operator if engine is normal

Electrical system
i) Alternator-charge the battery/produce charging
ii) Regulator-regulate the charging of battery charge/control the voltage
iii) Distributor-distribute high voltage current to various spark plug for fire

Transmission system,
a) Clutch- to connect and disconnect power
b) Differential- to equalize power for turning
c) Gear-box- to select speed and direction
d) Final drive- to reduce speed and increase torque
e) Drive wheels- to propel the machine

Give the function of each of the following parts:
i) Muffler -to reduce the noise of combustion of an engine,



-exhaust from the engine is passed through a muffler,
-the muffler is designed so the gases expand slowly.

ii) Governor -Maintain a selected speed

-Limit the slow and fast speed
(4 marks)

Please state the roles of the following component in the engine system.
a) Camshaft
• Is turned by the engine crankshaft.
• A lobe (cam) on the camshaft causes the cam follower and push the rod to push the
valve open
• The spring closes the valve when the cam allows the push rod and cam follower to
return to low side of the cam
• Cam movements are designed to open or close the valves at the right moment

b) Clutch plate
• A clutch plate made of friction material is pressed on to the flywheel by a pressure plate
that is spring loaded either by a number of coil springs or a spring diaphragm.
• Clutch plate fitted with torsion springs to retain its shape.

• The clutch plate and the pressure plate rotate together with the flywheel and power is
taken out to the gearbox through a gearbox input shaft.

• The clutch is said to be engaged.

Explain the terms below:

a) Diesel injection pump- the fuel pump moves fuel from the tank and pushes it through the
filter

b) SAE number -stands for society of automobile engineers
-it is a means of classification of lubricating oil according to the
viscosity/thickness
-gear and transmission oil are given this number SAE 50, 70, 90.



c) Compression ratio - Compression ratio is a characteristic of an engine i.e. related to
engine efficiency i.e. the ability of the engine to convert in the
fuel to useful mechanical energy

d) Valve timing- -Opening and closing of both inlet and exhaust valves when the piston is
at the exact top (TDC) or bottom (BDC) of its stroke.

e) Valve overlap- -Both valves are open at once at the same period.
(10 marks)

Briefly describe the construction and function of the following:

a) Cylinder head -upper part of the engine
-contain holes valve
-made from cast iron at combustion chamber
b) Cylinder block -largest part in the engine
-have valve
-piston move up and down in the cylinder block
-make from cast iron
c) Piston -made from cast iron
-transfer and receive energy during combustion process
d) Piston rings- - A component that fitted into the slot around the piston which seal the
combustion chamber and help transfer heat

e) Cams - Integral part of camshaft design to open the valve at the correct timing
and to keep them open for the necessary duration.

f) Crankshaft- - Receive the force from the pistons and transmits it as rotary driving
force
- Rear end carries the flywheel incorporating starter ring gear
- Front end carries crankshaft gear used to drive valve timing mechanism,
oil pump

g) Intake and exhaust valves
-The valves allow fuel-air in and exhaust gases out of each cylinder during
combustion cycle by opening and closing the intake and exhaust parts of
the cylinder.



h) Gudgeon pin- -Forms the link between the small end of the connecting rod and the
piston.

i) Connecting rod- -bring down the energy that produce from piston to crankshaft

j) Flywheel- -rote to start the engine
-located at the end of crankshaft
(10 marks)

Define the term below:
i) Theoretical field capacity (TFC)
• Is the maximum possible capacity obtainable at a given speed, assuming the machine is
using its full width.
• TFC uses two of the factors – speed and width.

ii) Effective field capacity (EFC)
• The best way to determine EFC of a machine is to make an accurate check of the
number of acres (hectares) actually covered over a long period of time.
• EFC brings in the factor of efficiency. This capacity determination represent the real life
or actual capacity obtainable over a period of time

iii) Field Efficiency and the factors that influence the field efficiency of a machine. (9 marks)
• Speed - average rate of travel in km/hr.
• Width - distance in feet/meters across the processing portion of the machine.
• Efficiency -ratio of effective capacity of a machine to its theoretical capacity.
-an indicator of how much time is spent working versus turning, filling
hoppers and other jobs.

Explain why maintenance is important for an engine and describe the maintenance procedures
for the following:
a) Diesel system and diesel fuel system
• Clean the fuel filter
• Change whenever necessary
• Make sure the fuel tank is always top-up
b) Transmission system
• Check transmission oil as recommended
• Change oil filter as necessary
c) Power-Take-Off (PTO) system
• Change the hydraulic oil



• Change the filter when necessary
• Change the hoses and join foe leakage
d) Lubricating system
• Check the lubricating oil using dipstick if low add lubricating oil
• At the oil filter, dist is taken out of the oil to help it keep clean
e) Cooling system
• Check water in the radiator if low top up the water
• Check the connecting hose may be it has cracks (10 marks)

Lubricating system
1. Oil strainer
• filter dirt and foreign material
2. Oil galleries
• allow lubricating oil pass way for oil to move through to the components that are move
it
3. Pressure gauge
• it helps to measure the pressure of the lubricating oil
4. Oil pan/sump/crankcase
• reservoir for lubricating oil/storage lubricating oil
• cool the lubricating oil
• located beneath the engine block
5. Regulating valve
• Control oil pressure and by pass oil at filter & oil cooler
6. Oil pump
• Located in the oil pan
• Drive from either the camshaft or the crankshaft
• Supplies oil under pressure to the various parts of the engine
7. Oil filter
• Cleans the oil particles of foreign material
8. Oil cooler
• Help dissipate heat
9. Oil heaters
• Use in winter to make starting easier

Write short notes on the following
1) Fuel injection pump
• The function is to pump diesel go to injector nozzle.



• Fuel from the filters enters into the fuel injection pump which works to pressurize it. It
not only has to inject the fuel at the correct pressure but also at the correct time. Along
with the governor, it is also controls the amount of diesel discharged per injection and
hence the engine speed.

In a carburetor, explain the role of:
I) Choke system
• Control the supply of fuel to the engine. When starting the engine in cold weather, it
can be partly closed, forming a greater vacuum. This vacuum causes more fuel and less
air to be drawn into the combustion chamber. The richer mixture burns easier
ii) Venture (lubang-lubang masuk udara)
• The venture principle is used to create fuel flow from the float bowl to the main
discharge nozzle in the venture.

iii) Throttle valve
• Control of the rate at which some fluid moves from a region of relatively high pressure into a
region of relatively low pressure. An example would be in an automobile engine, where the
throttle controls the rate at which air (at or above atmospheric pressure) enters the engine's
intake manifold (near vacuum when the throttle is closed.)

iv) needle valve
• Control the flow of liquid or gas so that the flow can be decreased gradually and ultimately shut
off completely. Needle valves help protect fragile gauges that might otherwise be damaged by
high amounts of a pressurized substance's release

Differentiate between the two systems below:
a) Force-feed lubrication system and Petroil lubrication system
• Lubricating system is the lubricating system for big engine and very reliable
• Its configuration of component will ensure the delivery of lubrication oil to every moving
parts

b) Liquid Cooling system and Air Cooling System
Air cooling system Liquid cooling system

• Used primarily on small engine or • Normally uses water as a coolant
aircraft as it is difficult to route air to • The circulates in a jacket around the
all the heat points of lager engine cylinders and cylinder heat
• Metal baffles, ducts, and blower are • As heat radiates, it is absorbed by the
used to aid in distributing air. water which then flows to the radiator



c) Fuel Injection Pump of Diesel Fuel System and Carburetor of Petrol Fuel System
• To control the fuel discharge in terms of quantity, timing and correct order of cylindered
through the nozzle sprayer before enter into the combustion chamber.

d) Battery Ignition system and Capacitor Discharge Ignition system (8 marks)
• Although they perform the same job but battery ignition system differs in terms of
mechanical component which doesn’t exist in capacitor discharge ignition system, the
BIS using mechanical broken points to break and close the circuit.

Discuss four (4) major differences between diesel and petrol engines. (8 marks)

DIESEL ENGINE PETROL ENGINE
1. Fuel System 1. Fuel System
• Use diesel • Use petrol
• No carburetor • Have carburetor
• Uses heat & compressed air for • Uses electric spark to ignite air-fuel
ignition mixture
2. Higher compression ratio 2.Lower compression ratio
• 14 – 16 : 1 • 7 – 10 : 1
3. Operation 3.Operation
• No pre-mixing of air and fuel • Fuel and air mixed outside the
• Air taken into cylinder through intake cylinders in the carburetor and intake
manifold and compressed manifold
• Fuel is sprayed into cylinders and • Mixture is forced into cylinders by
mixed with air as the piston nears the partial vacuum created by intake
top of its compression stroke stroke of piston

Name the different types of brake systems.

• The main types of brakes are disc brakes, drum brakes, air brakes, and vacuum brakes.
• A brake is an apparatus used to slow or stop a moving vehicle, or, once the vehicle is
stopped, to keep it from moving again.
• Wheel brakes are generally friction devices, using resistance and energy lost through
heat to slow the vehicle.
• The vacuum brake was originally devised for use on trains.
• These types of brakes works by creating air pressure changes in a compartment called
the brake cylinder. Inside the cylinder is a piston, which is a mechanism designed to use
the force of incoming air to move a rod. The rod is attached to the brake shoes. When



the brake pedal is held down, air is let into the cylinder, which causes the piston to
transfer that force onto the brake rod. The brake rod moves and, in turn, the brake
shoes are pressed to the side of the wheel to cause friction. (10 marks)

a) What do you understand by agricultural mechanization? (2 marks)
• Needed to ease the operations of crop production by the use of machines to replace
animal and human labor.

b) Name and describe any two objectives of mechanization. (4 marks)
• Reduce human labour.
• Increase farm productivity through higher yield per unit area.
• Distribution of labour for other activities.
• Efficiency of field operation and reduction of labour at peak hour activities.

c) Although having a farm tractor is good for field activities it may also bring along some
disadvantages. List five disadvantages of owning a farm tractor. (5 marks)
• Tractor are expensive to buy/high investment
• High cost of maintenance
• Need a high skills and handlings maintenance
• Farm work may be stopped, disturbed, if tractor break down
• The tractor is value depreciate over time/low resale value.

Describe five (5) common obstacles to farm mechanization and provide a solution to each
problem. (10 marks)
1. Direct increase in the yields:
• Example of equipment purchased in order to increase yields directly are
irrigation and spraying equipment
2. Indirect increase in the yields:
• Any investment in cultivation equipment to improve the condition of the soil in
seedbed preparation would come under this heading
3. Increased yield through improved timeliness:
• The speeding up of operation by mean of a larger, faster machine will raise
average yields in an uncertain climate because of better timeliness
4. Increased price through higher quality:



• Extra return may be achieved by obtaining a higher price as well as through
better yields
5. Increased price through storage:
• A higher price may also be obtained through storing the crop until later in the
season

List ten safety procedures while working in the farm workshop. For, describe what may happen
if it is not followed. (10 marks)

Tools:
1. Extension cables should be as short as possible
• If the cable on drum, it should be completely unreeled to stop the wire
overheating
2. Do not wrap your fingers tightly round a spanner
• There is much risk of loosing the skin from your knuckles
3. Power tools must be well maintained
• Never use an electric tool unless it is earthed correctly or double insulated
4. Google must be worn for eye protection when grinding
• Without this precaution the metal might pick up on the drill bit and turn with it
Electric shock:
5. Avoid electric shock is never to work with life electrical equipment
• Poster should be display in every farm workshop. If this happens to someone
else while you are near, some rapid action is needed
Compressed air:
6. Never direct compressed air at the body
• Can cause serious injury
Welding:
7. Never look directly at the glare of electric welder
• A painful eye condition known as ‘arc-eye’.
Jacks:
8. Always apply the hand break and choke the wheels of tractor before it is jacked up
• Never use bricks or concrete blocks because they may crumble or slip



Personal protection:
9. The best clothing for workshop use is a boiler suit
• If not follow them may be happened accident such as falling object on the leg
First aid:
10. There must be a first aid on the farm workshop
• If have not there is too difficult for accident treatment

The old farm tractor in the garage has been left idle for three months because there was not
much field work to be done. The driver was only instructed to ignite the engine twice or three
times a week for a few minutes to warm it up. What do you need to do to the tractor before
you drive it out to resume normal field operations? List eight of them. (8 marks)
Recommend service intervals:
After 500 hour of operation
• servicing the distributor
• timing the ignition
• maintaining the starter and generator (or alternator)
• servicing diesel engine fuel filters
• servicing front- wheel bearing
• maintaining the cooling system
• checking and servicing others parts of the tractor
After 1000 hour of operation
• cleaning the tractor
• servicing the oil-bath air- cleaner assembly
• servicing the drive mechanism
• servicing the hydraulic systems
• adjusting the engine governor

Briefly discuss the planning of farm mechanization in plantation to ensure the entire task to be
done in a proper manner in order to maximize the profit and reduce cost and risk. (10 marks)
Labor:
• can be measured in terms of hour or cost but also in term of ‘quality’
• the operation is key factor in success in the field
Planting:



• it is necessary to identify the type of machines required and specify their required
performance level
Size and type of machine:
• the types depend partly on the requirements of the job and limitations of the
environment and partly on what is available in the machinery market
Total planning:
• the way the physical characteristics of a machine fit in with the rest of the plantation
• the overall balance of power requirement being kept at a reasonable level throughout
the year
Specification of machines:
• There is only one real way to select machines and that is to list everything it has to do
and everywhere it has to go
Name three basic types of tractor, based on their design configurations (3 marks)
• 2 wheel drive
• 4 wheel drive
• Crawler tractor

Name 4 different types of tractor (4 marks)
• Standard tread

• Row crop

• High clearance

• Low profit

Briefly explain the two main reasons for carrying out maintenance work on tractors. List down 4
main maintenance work commonly being carried out on tractors (10 marks)
Main reason:
• To keep the engine operation at maximum efficiency
• To prevent wear of engine part
Main maintenance:
• Cleaning the engine
• Cleaning carburetor air cleaners
• Cleaning fuel filter
• Cleaning fuel tank vent cap
• Cleaning crankcase breather
• Checking oil level
• Changing oil in the four-cycle engine



• Lubricating of two-cycle engine

List 4 types of tractor tyre tread commonly used for field operations. (4marks)
• General purpose tread
• Industrial lug
• Floation
• Deep lug/rice tread

There is various kind of power in farm mechanization. List types of power basically can be
determined in the tractor. (4 marks)

• Brake
• PTO
• Drawbar

Why proper valve adjustment is important in engine process? Briefly discuss. (4 marks)
• Engine will use fuel more efficiently.
• Engine will start more easily.
• Maximum power will be achieved.
• Valves will give longer service.
• Overheating of engine is less likely to occur.

The diesel fuel-injection system must perform five (5) basic functions. List the five (5) functions.
(5 marks)
• Supply the correct quantity of fuel/diesel
• Time the fuel delivery
• Control the delivery rate
• Break up or atomize the fuel
• Distribute fuel evenly through the cylinders

Compare and contrast the process of the compression stroke of a diesel 4-stroke engine and
gasoline 4-stroke engine. (5 marks)
compression stroke of diesel 4-stroke engine compression stroke of gasoline 4-stroke
engine

• It compresses the fuel air mixture •
• During the this stroke, both the intake
and exhaust valves are close



Explain what happens to the piston, valves, spark plug and fuel-air mixture during the
compression stroke and exhaust stroke of a four-stroke petrol engine. (10 marks)
compression stroke exhaust stroke

• The piston moves up while both the • The cylinder will be filled with waste
intake and exhaust valve are close. gas at the end of the power
• This will result in the compression of • In the exhaust stroke, the piston
the trapped fuel-air mixture moves from BDC to TDC.
• When the piston approaches TDC, the • At this time, the exhaust valve is
spark plug produce a spark to ignite opened and the waste gas moves out
the mixture through it and into the environment
via the muffler.

Explain the energy conversions in an internal combustion engine. (4 marks)
• Form of heat engine because heat engine produced by the burning of fuel within the
engine is changed into mechanical energy.
• Is a structure that converts chemical energy (fuel) to mechanical energy
• Usually made available on a rotating output shaft.
• Normal engine that been used on road is known as Internal Combustion Engine (IC).
• Is a reciprocating engines that have pistons that move back and forth in cylinders within
the engine

What are 'lean' and 'rich' mixtures, and how can one be changed to the other? (4 marks)
Too rich mixture -Fuel consumption increased
-Cause carbon deposits to accumulate in combustion chamber
Too lean mixture -Reduces power
-Valve burning from extra hot slow burning gases

What are the four (4) basic components of the intake system?
• Air cleaner
• Intake manifold
• Combustion chamber
• Carburetor
• Intake valve

Give three (4) functions of exhaust system.
• Carry away burn gases from combustion chamber
• Reduce muffling of engine noise



• Reduce heat at the engine

List three (3) basic components of the exhaust system. (10 marks)
• Muffler
• Silencer
• Exhaust valve
• Exhaust manifold

Name three (3) types of engine lubricating system in which they are commonly found and how
full face feed system work? (6 marks)
Type of engine lubricating system
• Circulating splash
• Internal force feed and splash
• Full internal force feed
How full face feed system work?
• Oil pump pushes oil through the system.
• A reserve of oil is stored in the crankcase for circulation through the system.
• At the oil filter, dirt is taken out of the oil to help it keep clean.

List 5 major parts involve in the lubricating system. (5 marks)
• Oil pump
• Crankcase
• Oil cooler
• Oil filter
• Pressure regulating valve
• Pressure gauge

Give three main functions of an engine lubrication system (3 marks)
• Reduces friction between moving parts
• Absorbs and dissipates heat
• Seal the piston rings and cylinder walls
• Cleans and flushes moving parts
• Helps deaden the noise of the engine



Write short notes on the effects of overheating in the cooling system of an engine. (5 marks)
• Burned valves and spark plugs
• Scored pistons
• Lubrication failure
• Excessive engine wear
• Engine knock, Detonation, Pre ignition
• Cylinder head and block can warp
• Rings and valves may seize or stick due to gums, lacquers, and varnishes forming from
overheated oil and carbon formation.
• Bearings may be damaged causing excessive wear.

2 type of fans that are commonly used in the engine cooling system
• Blower fan
• Suction fan
Cooling system
i) Pressure cap/radiator cap
-reduce temperature of water in cooling system
-to allow atmosphere pressure to enter the cooling system

ii) Connecting hoses
-help to reduce from vibration of the radiator
-allow water to pass from engine block to the radiator
-the flexible connections between the engine and other parts of the cooling system

Describe 3 problems that can happen to an engine if there is no cooling system (3 marks)
• Overheating could burn up engine a short period
• Lubricating failure
• Excessive engine wear

Discuss three major function of the engine cooling system (3 marks)
• To prevent overheating of the engine
• To regulate temperature at optimum level
• To prevent from overheating

Describe three (3) functions of the carburetor. (6 marks)
• Atomizes fuel for the engine
• Provides proper fuel-air ratio
• An air tube which operate by a change in air pressure.



List ten (10) components of the electrical system and explain their functions. (10 marks)
• Starter- Activate the flow of current in the starter circuit.
• Ammeter-Indicate the amount of charging produce by alternator to charge battery
• Alternator-Charge the battery/produce charging
• Voltage regulator-Regulate the charging of battery charge, and control the voltage
• Starter solenoid-Attach the starter motor, to assist the starting of the engine
• Starter motor-Start the engine with rotate the flywheel
• Distributor-Distribute high voltage current to various spark plug for fire
• Coil-Increase the low voltage to the high voltage of battery
• Battery-Supply energy to the circuit
• Spark plug-Produce spark in the combustion chamber

What is the main purpose of an electrical system on a tractor? List various other purposes of
such system. (5 marks)
• Recharge the battery after its electrical power is used up to start the engine or other
electrical devices e.g. lights, horn, etc.
• Generates current during operation.

Purposes such Regulator system
• Closes the circuit when engine is running & open the circuit when the engine is stopped.

• Prevents overcharging the batter.

• Prevent high flow of current through the system that could damage other components.

Give some examples of preventive maintenance for an electrical system on a tractor.
(4 marks)
• Servicing and maintenance of battery
• Servicing of spark plugs
• Servicing the distributor
• Replacing breaker point
• Servicing alternator and starting motor

Name two type of generator and kind of electrical current each one produces (3 marks)
• High tension wiring
• Distributor cap
• Low voltage



• High voltage
• Primary current

What is the major function of battery charging circuit (2 marks)
• Receives and stores electrical charge that enters into it and supplies the electrical
charge to other electrical devices.

List 4 component involve in the battery charging circuit. (4 marks)
• Battery
• Regulator
• Dynamo
• Ampere Meter

Explain the operation of the cranking or starting circuit. You are to list down the four basic parts
of starting circuit. (10 marks)
Battery - supply energy to the circuit.
Starter switch - activate the circuit.
Motor switch - engages the motor drive with the engine flywheel.
Starting motor - drives the flywheel to start the engine, As soon as the engine starts, the
starting motor disengages. It is designed to handle heavy loads
for short periods of time only.

What device is used to make starting easier in a magneto ignition system? (2 marks)
Starting motor
• Drives the flywheel to start the engine. As soon as the engine starts, the starting motor
disengages. It is designed to handle heavy loads for short periods of time only.

What is the difference between a dynamo and alternator? Explain their principles of operation.
(4 marks)
Dynamo Alternator

- driven by the engine by the transmission belt - charge the battery and produce charging.
and it supplies direct current to the battery.

List three basic function of a regulator in the charging circuit. (3 marks)



• Closes the circuit when engine is running & open the circuit when the engine is
stopped.
• Prevents overcharging the batter.
• Prevent high flow of current through the system that could damage other components.

Stage three major function of ignition distributor in the engine ignition system (3 marks)
• To have available, at the proper spark plug
• Enough voltage to cause a spark to jump the spark-plug gap for ignition of the fuel-air
mixture in the cylinder.

Name five (5) agricultural implements that are powered by the tractor's PTO system and name
another five (5) secondary tillage implements that are not PTO driven. (10 marks)
PTO system not PTO driven

• Slasher • Harrow
• Rotovator • Fine spring time
• Auger • Ridger
• Boom sprayer • Spring fine cultivator
• Bailer • Mulcher
• Shredder • Leveler

What is the differential lock and how does it work?
• To break the differential component in transmission system
• Both wheels are in same speed to make a corner.
• Used it to down moth and wheel are embed
• For factor that in rood
Give 4 major component of power transmission system in an agricultural tractor
• Clutch
• Gearbox system
• Differential
• Final drive
• Drive wheels

Briefly discuss the basic construction and operation of the PTO in a tractor. (4 marks)



• Is an attachment in the power train of a machine, it drives auxiliary equipment.
• Normally gear driven from the transmission and send power through a shaft to the PTO
outlet where the driven equipment is coupled.
• Drive equipment at standard speed of 540 – 1000 rpm.
• Operated by a clutch release, which is sometimes part of the main engine clutch.

Name 3 types of PTO system and function in how the clutch system operation
• PTO, normal type
- PTO takes its rotation from the engine through the same clutch as the gearbox
therefore engaging the clutch starts both the tractor and the PTO.
• PTO, live type
- Clutch of the dual plate type controlled progressively by a pedal.
• PTO, fully independent
- Tractor provided with 2 clutches, one for gearbox and the other for PTO.

List the four function of transmission system for a farm tractor (2 marks)
• To connect and disconnect power
• Select speed ratios
• Provide a means of reversing
• Equalizes power to the drive wheels for turning

In the term tractor hydraulic system, write short note regarding function and operation of the
following components:
• Tree-point linkage
-used for hitching mounted and semi mounted implement. It consists of one top link.
• Position control system
-in the hydraulic control of an attached and allow the operation to pre select and to
position the implement as determined by the position of hand control levels.
• Automatic draft control system
-will automatically raise or lower an implement as the draft or resistance of the attached
implement increase/decrease.
-the position of the hand control level, effect established the draft to mount.

Name the two basic types of hydraulic system (2 marks)
• Open-center system
• Closes-center system



Explain the six (6) advantages and two (2) disadvantages of hydraulic system. (16 marks)
advantages of hydraulic system disadvantages of hydraulic system

Flexibility: power can remove to any location Efficiency: mechanical system is better than
hydraulic system

Simplest the system Need for cleanliness

Compactness Need more maintenance

Safety

Economy

Describe how the basic hydraulic system operates in a tractor. (4 marks)
The basic hydraulic system has two components, namely the pump which moves the oil and the
cylinder which uses the moving oil to do work
Explain the difference between broadcast and full width fertilizer distributors. Name four (4)
types of broadcast distributor. (6 marks)
broadcast full width fertilizer distributors

• These have a hopper for the fertilizer • Other type of fertilizer distributor
with a spreading mechanism • Unlike broadcasters, this type of
• The drive is usually from the PTO but distributor is almost as wide as the
some machines have hydraulic motor spreading width when it is in work
drive • 2 types of full width distributor: 1 has
• Most broadcasters are mounted but mechanical feed, the other is
the largest capacity models are trailed pneumatic
• Either a spinning disc or oscillating
spout is used to distribute the fertilizer

Types of broadcast distributor:
• Spinning disc
• Mounted machines
• Pendulum or oscillating spout

Proper mounting procedures have to be followed if the plough is to work efficiently. List down
the steps in the mounting procedures (10 marks)
• The support wheels and accompanying frame structure required on pull-type implement ere
eliminated, and a single depth or height control system, which is part of the tractor, serves
for all or most of the mounted and semi-mounted implement used with any one tractor.



• Maneuverability, visibility, ease of transport, and the advantage gained by draft sensing and
weight transfer through the tractor’s control system make mounted implements popular
standardization of the three-point hitch and quick-attaching couplers, to permit
interchangeable use of different makes of equipment, has made attaching and detaching of
mounted and semi-mounted implements a simple and easy operation.
• The physical size and weight of equipment that can be mounted on the rear of a tractor and
fully supported by it are limited by the carrying capacity of the tractor chassis and by the
transport stability limitations of the combination.
• Semi-mounting, in which the tractor carries only part of the weight, overcome these
limitations and stills the advantage of maneuverability, lower investment cost and the
ability to utilize the tractor’s draft-sensing system.
• Semi-mounting, in preference to full mounting, is particularly appropriate for moldboard
plows having more than 4 or 5 bottoms, because their weight and great length would
produce an excessive moment on the tractor, thus causing instability during transport.

There are basically four (4) general types of field implements based upon their relation to the
power unit. Briefly discuss each of these types of field implements. (10 marks)

1. Pull-type or trailed implements

• Is one that is pulled and guided from a single hitch point and is never completely
supported by the tractor.

2. Mounted implements

• Is one that is attached through a hitch linkage in such a manner that it is completely
supported by the tractor when in raised it position.

3. Semi-mounted implements

• Is attached to the tractor through a horizontal or nearly horizontal hinge axis and is
partially supported by the tractor, at least during transport, but is never completely
supported by the tractor.

4. Self-propelled machine

• In comparison with pull-type units, self –propelled machines tend to provide more
flexibility and better maneuverability, better visibility and control by the operator and



improved with field harvesting equipment, field operating losses are minimized because
the cutting or gathering unit is across the front of the machine rather than projecting to
one side.

Name six types of soil tillage implements (3 marks)
• Mouldbord
• Disc plough
• Sub soilers
• Rotovator
• Harrow
• Ridger

List 4 different types of implements for crop planting or seeding operation (4 marks)
• Disc plough
• Chisel plough
• Sub soilers
• Rotary tillers

Name four different implement for dry mineral fertilizer applications (4 marks)
• Spinning disc
• Mounted machine
• Pendulum or oscillating spout

• Mechanical feed

• pneumatic

With the aid of a diagram, list the eight (8) major components of the mold board plow and
explain the function of each component. (10 marks)
• The crass shalf -a still shalf to which the beam DF individual plow are mounted
• The beam -on which the pull of the tractor is exerted and to which is
mounted the leg and courter
• The frog -which is mounted the share mould board and the landslide
• The courter -which is mounted on the beam ahead of the plow body. It makes
a vertical cut into the soil as the plow is drawn through
the soil



• The leg -which is mounted the shared, mould board and the landslide
• The share -which is mounted in front of the flog and which act to make a
horizontal run into the soil
• The mould board -which acts to rats, overturn and bleak up the furrow slice the has
been cut
• The landslide -a flat rectangular pieces of metal which act to make on the side
thrust on the plow as it is drawn through the soil

What is tillage? (2 marks)
• The mechanical modification of soil structure to make it suitable for seed germination
and growth.

What is the purpose of tillage? (6 marks)
• To get suitable medium for seed germination and rood growth by loosing up the soil
structure
• To improve soil aeration and water absorption
• To destroy weed
• Plant residue
• To control insect pest & diseases
• To control soil moisture levels

Why is secondary tillage necessary for seedbed preparation and plant growth? Explain five (5)
benefits that can be achieved from this operation. (5 marks)
Why is Secondary tillage?
• The large soil clods resulting from primary tillage are not suitable for seed germination
and plant growth.
• To improve the rood penetration
• Give opportunity to seed emergence
Benefits:
• High whc
• Destroy pest and disease
• Destroy weed and grass
• Improve soil fertility
• Break down the bigger part of soil into the small part
• Prevent soil erosion



Compare and contrast primary and secondary tillage. List three implements that are used for
primary and secondary tillage. (5 marks)

Primary tillage Secondary tillage

• more aggressive, deeper operation and • works the soil to shallow depth
usually • levels and firm the soil
leaves the surface rough cut and • closes air pockets
shatters soil • kill weeds and helps conserve
moisture

Implements: Implements:

1. Mouldboard and disc plough 1. Disc, spring tooth and spike tooth
harrow
2. Chisel plough
2. Spring and rigid tined cultivators
3. Sub soilers
3. Ridgers, bedders or listers
4. Rotary tillers or cultivators
4. Roller pockets and roller harrows

5. Weed control implement

What are the constructional features required if you are to design a general purpose seed drill?
List the components and explain the function of those components. Explain how the seeding
rate of the above seed drill is calibrated. (10 marks)

= 10,000/N x C x W
= kg/ha

Construction of major components of Seed Drill:
• Full width seed box to hold seeds
• Furrow opener- to cut open a shallow furrow into which seeds are to be placed.
• A metering device or feeding mechanism- meter out the correct amount of seeds for
each row.
• A seed hopper- to deliver seeds from feeding mechanism and drop into the furrow of
each row.
• A pair of land wheels - support the planter and to drive the feeding mechanism



Name four kind of seed drills (4marks)
• Row crop planter-trailing drill
• Front tractor mounted
• Rear tractor mounted
• Broadcast cop planters

Why do we need irrigation agriculture activities? (4 marks)
• Increasing demands of water
• Limited availability
• Costing
• To provide water for plant growth
• To obtain optimum yield

What is irrigation?
• Not much new land waiting to be opened up for agriculture. The main increase in food
supplies has to come from making better use of land already farmed
• More efficient crop production will help e.g. better varieties, more use of fertilizer,
mechanization, etc. but rainfall is still a limiting factor for a very large proportion of the
earth’s surface and so irrigation is important in increasing production
• With irrigation, crop yields may be made more reliable, or two crop a year may be
possible instead of one

List the advantages of irrigation system. (4 marks)
• To supply moisture which allows plant growth where there was none before, or to get
better growth, or to extend the growing season
• An insurance against drought
• To allow the movement of plant nutrients. The chemicals for plant growth are absorbed by
the plant in solutions
• To leach undesirable salts, that is to wash them out in solution
• To control the environment for growing plants. E.g. prevent frosts, to keep plant cool or to
keep them moist

Types of irrigation method:
• Subirrigation
• Surface irrigation
• Sprinkler irrigation
• Microirrigation



Give 2 basic types of spray liquid chemical applications (2 marks)
• Reaction rotation sprinkler
• Fixed head sprays

• Perforated pipe
• Slow rotation sprinkler or Rain gun

Explain three (3) factors that can influence the application rate of ground crop sprayers.
(6
marks)
• Tractor forward speed
A low forward speed gives a high application rate. By changing gear to double the
forward, the application rate will be halved.
• Spraying pressure
Higher application rate are obtained by adjusting the relief valve control to increase
working pressure. High pressure reduces droplet size and increases the risk of the
chemical being blown away by the wind (drift)
• Nozzle size
Nozzles with a large hole will give a high application

In an ideal cycle of four stroke petrol engine, the valves open and close exactly at Top Dead
Center (TDC) and Bottom Dead Center (BDC). But in actual working condition, the valves open
and close before or after the piston reaches the TDC or BDC. Explain in detail the reason why:
(i) The intake valve opens 15° of crankshaft rotation before TDC on the exhaust stroke,
• To allow more FAM to enter into the combustion explanted

(ii) The exhaust valve opens 50° before the piston reach BDC. (4 marks)
• To allow for smoke from combustion to flow out early and thus make an empty space
for the FAM to fill up

In order to ensure the maximum life of an engine, it must be maintained regularly. Answer
following questions regarding engine maintenance.



a) What is the tool use to set the clearance between the valve tip and rocker arm during
maintenance of the valves?
• Feeler gauge or micrometer or hole page

b) What must be done if the petrol engine runs too fast at idling?
• Adjust the timing by screwing up or down the choke valve

c) What must be done if one of the cylinders does not produce spark during the power stroke?
• Change the spark plug or check the electrical circuit system

d) What are some basic maintenance that should be carried out at every 50 working hours of
tractor?
• Change oil, oil and fuel filter, clean up the air filter and clean the engine from debris/dirt

e) What type of lubrication oil is used inside the engine body in our country?
• SAE 30, SAE 30w or SAE 30-50

f) Which piston ring must be replaced if the black smoke from exhaust pipe is too thick?
• Middle ring

g) What may possibly prevent the engine from starting although it can be cranked at normal
speed at starting?
• Ignition system defective

h) What may cause the engine to overheat faster than usual during normal engine operation?
• Late ignition timing
i) What may cause exhaust smoke to turn blue?
• Excessive oil consumption

j) What may happen if the regulator is removed from the circuit leaving the alternator to be
directly connected to the other electrical devices? (10 marks)
• Electrical devices may damage because of high current flow into

For engine to operate, a definite of events must occur in sequence. List the four events in
sequence (4 marks)
• Fill cylinder with combustible mixture
• Compress mixture into smaller space
• Invite mixture- causing it to expand and produce power



• Remove burned gasses from the cylinder

What does it mean to ‘bleed’ the fuel line and when must this be done? (3 marks)
• Removed air tube
• When the diesel tank is empty and the engine tractor stop

Tractor has been referred to be a 'central power station' in order to provide power for many
operations or activities during mobile or stationary operations. List five (5) major functions of
some of the power outlets in a tractor and examples of the equipments that use each of those
outlets. (10 marks)
• To provide easy and accurate control of the equipment from the tractor drive’s seat

• To provide electric starting, light and light-signalling

• Have rapidly become common place include such item as multi-speed gear-boxes, live
power take-off, differential lock, power steering and various devices for transferring
weight

What are the factors that may affect the field efficiency? Or list five (5) factors that can affect
the field efficiency. (5 marks)

• Not using the full capacity of the tractor
• Refilling procedures
• Transporting procedures
• Repairing of machine in the field
• Irregular resting hours
• Cleanliness of implements
• Rest of operation
• Adjustment of implement

What other alternatives that can be used to reduce the seeding rate? (2 marks)
• Treatment the seeds
• Apply good distance
• The best practice for planting

What are the factors that will result in the increase of the horsepower required for the same
size machine? (3 marks)
• Moving the tractor over the ground
• Pulling the implement over the ground
• Powering the implement for useful work


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