NSQF Automobile midterm Notes 2021-22
NSQF Automobile midterm Notes 2021-22
SECOND P.U N.S.Q.F LEVEL-4
AUTOMOBILE SUBJECT
MID TERM PORTION.
UNIT -1SERVICE MANUAL
Session=01.
UNIT-2INSPECTION AND REPAIR OF FASTENERS
Session= 01 TO 05.
UNIT-3MEASURING EQUIPMENT’S
Session=01 TO 04.
UNIT-4SERVICEABILITY, REPLACEMENT OR REPAIR OF ENGINE
COMPONENTS
Session= 01 TO 04.
UNIT -6SUSPENSION SYSTEM
Session= 01TO 06.
N.S.Q.F
LEVEL 4
AUTOMOBILE
NOTES
UNIT 1 ---
SERVICE MANUAL
SESSION 1 – READING OF SERVICE
MANUAL
I.
FILL IN THE BLANKS
1.
Service manual are important for maintaining originality in performance
2.
Service manual is used for service technician
3.
Service manual is available with a service center/service
advisor
4.
Mechanic use service
manualfor any defect in a vehicle.
5.
The manufacturers develop service manual.
6.
The automobile
today has many electrical electronic gadgets which operate only at specialized voltages,
amperage and resistance
7.
Service manual
should be kept in handy place.
8.
This helps
technician to take appropriate decision to solve the problems the service
manual also gives circuit diagram with color code
9.
The technician must use the service manual
regularity to check the serviceability of component this helps the technician to
decide about replacement
of component.
II.
Answer the following question:
1. Why service manual is used?
ANS: Service manual used for,
*) The technician/mechanic must use the service manual regularity to check the serviceability of component. This helps technician to take appropriate decision to solve the problem.
2.
Importance of maintenance.
ANS:Any product after purchasing of
some year it requires maintenance to maintain originality of that product so
that it is very imp to of maintenance. It
is also the key to successful maintenance ofany motor vehicles.
3. What are the content of vehicle service
manual?
ANS: The content of vehicle service
manual are.
·
Index*Page
number*Expanded
view of assembly*Disassembly
sequence
·
Tolerances, gazes, sizes of components*Serviceability*Life span
·
Decision for Repair or Replacement*Assembly procedure and Working
test procedure
4. Who develops the service manual?
ANS: The service
manufacturers develops service manual, which gives clear cut ideas of their
product like material used specification service limit span life of component
storage life
5. Importance of service manual.
ANS: Service manual helps mechanic to learn
new development, new changes, technique to disassemble, assembly procedure,
testing etc.
6. What are advantages of using
service manual?
ANS: Advantage of service manual are:
·
To learn new development, new changes,
technique to disassemble, assembly procedure, testing.
·
To
maintain originality in performance of vehicle.
·
The service manual helps to teach the
technicians to work on the vehicle systematically to solve the problems as well
as to provide service to maintain originality.
·
This helps the technician
to decide about replacement of component.
7. List the
areas covered by service manual
·
Expanded view of an unit/assembly
·
Name of parts with part number
·
The specification of each part and their tolerances in
assembly
·
Sequencing of disassembly and precaution
·
Sequencing of assembly with tolerance, play adjustment
etc.
·
Testing procedures and workability
·
Maintenance schedule
·
Replacement limit of components
·
Trouble shooting chart
· Use of special tools and their part number
UNIT 2
Fasteners:-
An automobile vehicle is an assembly of a large number of sub-assemblies
and components. The assemblies such as
engine-clutch-gearbox-differential-wheels-brakes etc.
Each of these assemblies is
formed by joining many components. Some of the components can move with respect
to each other, others are physically fixed together, with no relative motion
possible.
The first type of connection is
called a Kinematic joint,intended
to allow some motion) and the second type is called a Rigid
joint. Both types of joints are important in manufacturing
a vehicle.
The process and methods used for
joining depend on the type of joint, there are five most common methods of
joining:
. Mechanical fasteners
· Screws
· Bolts
· Nuts and
· Rivets
. Welding
. Brazing
. Soldering
. Adhesive bonding
In this we will study about
the fasteners used in automobiles.
Mechanical fasteners
Mechanically joins or affixes
two or more objects together. A fastener can be a bolt or a screw. Varieties of
fasteners are available in the market as shown in Fig-1 and can be selected
according to need or requirement.
Automotive fasteners are the mechanical devices or components
like bolts, nuts, screw, stud, rivets, shims, pin, tie rods etc. used for
holding or connecting two or more objects together in a structure.Fasteners are
widely used in number of industries such as aerospace, defense, automotive,
petrochemical, marine and pharmaceutical sectors.
Automotive
fasteners are made up of variety of metals such as stainless steel, iron,
brass, aluminum, nickel etc.
Session
1:Automotive bolts/machine screws
I. FILL IN THE BLANKS
1.
A fastener is a hardware device that
mechanically joins or affixes two or
more objects together.
2.
Automotive fasteners are made up of
variety of metals.
3.
A bolt is an externally threaded headed fastener,
which is used in conjunction with a nut.
4.
External threads are on the boltor screws
and internal threads are on the nut
5.
In the country we use ISO metric thread
6.
Machine screws have machine thread for use with a nut or
in a tapped
hole.
II. ANSWER THE FOLLING
QUESTIONS.
1. Define bolts?
ANSAutomotive Bolt is an externally threaded headed fastener, which is used
in conjunction with a nut.
2. Describe the importance of bolts.
ANS:Automotive Bolt is an externally threaded headed
fastener, which is used in conjunction with a nut. It should always be
tightened by holding the bolt head stationary and turning the nut.
3. Describe the importance of machine screws.
ANS:The machine screw is an externally threaded
headed fastener, which is tightened by applying torque to the head, causing it
to be threaded into the material it will hold.
4. What is importance of threads on bolt and machine screws and why threads
are important?
ANS:A thread is a ridge of uniform section
in the form of a helix on the internal or external surface of a cylinder. External threads are on the bolts
or screws and internal threads are on the nuts.
There
are two types or directions of the thread helix, left hand and right hand
threads. Most Common threads are right hand threads.
5. Differentiate between bolt and screw.
Bolt: Automotive bolts often known as threaded fasteners is
one of the types of auto fasteners that having a head at one end.
Screw:The machine screw is an externally threaded headed
fastener, which is tightened by applying torque to the head,Machine screws have
machine threads for use with in a tapped hole.
6.
What you understand by metric
thread? Make a profile of metric thread and state all the terminologies.
Pitch diameter: The pitch diameter of a parallel thread is equal to
half the nominal pitch of the thread.
Major diameter: The major diameter of a thread is the diameter of the
imaginary co axial cylinder that just touches the crest of an external thread.
Minor diameter:The minor diameter is
the diameter of an imaginary cylinder that just touches roots of an external
thread.
Crest:The crest of a thread
is the prominent part of a thread, whether internal or external.
Root:The root is the bottom
of the groove between the two flanking surfaces of the thread whether internal or
external.
Flank:The flanks of a thread
are the straight sides that connect the crest and the root.
Thread angle:The angle of a thread is the angle between the flanks, measured in an
axial plane section.
Pitch:The pitch of a thread is the distance, measured
parallel to its axis, between corresponding points on adjacent surfaces, in the
same axial plane.
7. List the materials used for bolt and machine
screw
Aluminum, Brass, Copper alloy, Plastic, Steel,
Hardened steel, Stainless steel, super alloy and Titanium
Session 2 Automotive Nuts
I. Fill in the blanks:
1. A nut is a
type of fastener with a threaded hole.
2. For joining
two metal part the nut is screwed on the bolt.
4. The nut can
have left hand or right hand internalthreads.
5. A hexagonal
nut is a type of metal fastener that has six sides.
II. Answer the following
questions:
1) What is nut?
ANS:A nut is a type
of fasteners with a threaded hole. Nut are almost used opposite a mating bolt
to fasten.
2) What are the material which
used to make nuts?
ANS:Aluminium,
brass, copper alloy, plastic, steel and stainless steel, super alloys titanium
etc.
3) Describe the importance of nuts.
ANS:Automotive
nuts, one of the important types of auto fasteners are usually square or
hexagonal shaped metal having a threaded hole which is used for screwing a bolt
that hold together.
4)
Why the nuts are made of four or six faces?
ANS:Because the
sides of 4 and 6 faces give enough faces for tool to grip and not to slip when
applying higher torque.
5)
What is importance of threads in a nut and why threads are
important?
ANS:For joining two
metal part the nut is screwed on the bolt. Therefore the thread profile of bolt
and nut must match. The pitch of the bolt and nut must be same else the nut
cannot be screwed on the bolt.
Because, thread in a
nut given to grip and not to slip when applying higher torque.
6)
Name different types of nuts used in automobile?
ANS:Automotive nuts
can be of different types such as simple nuts, collar nuts, locking nuts,
t-nuts, hex nuts, and jam nuts, lug nuts, plate nuts, self-locking nuts,
stainless steel nuts Heavy hex, square,
coupling, Flange, nylon insert lock, wing etc.
7) Differentiate
between bolt and nut.
Bolt:Automotive Bolt is an
externally threaded headed fastener, which is used in conjunction with a nut.
Nut: A nut is a type of
fastener with a threaded hole. Nuts are almost always used opposite a mating
bolt to fasten a stack of parts together.
8) What you understand by ISO metric thread?
ANS:All the dimensions are related to the internal
diameter of the nut.
SESSION-3: AUTOMOTIVE
STUDS
I. FILL IN THE BLANKS
1. Studs are mechanical fasteners
which are threaded
on one or both ends.
2.
Automotive studs are fastened
at both the ends with the help of an unthreaded shank.
3. Wheel studs are the
threaded fasteners that hold on thewheelof many automobiles.
4. Press-in studs are
installed from the back side of the diskor drum.
5. For a performance or heavy dutyapplication,
the use of studis
preferred whenever possible instead of main cap bolts.
II. Answer the following questions:
1. What is stud?
ANS:
One end is secured
to an object and the other end is with a nut,
2.
·
Engine Stud
·
Wheel stud
·
Stainless Steel stud
3. Describe the importance of studs.
·
Studs are mechanical fasteners which are
threaded on one or both ends. One end is secured to an object. The other end is
used typically with a nut.
·
Automotive studs are commonly referred to as a double
ended automobile fastener.
4. What are the advantages of studs over bolts?
·
Studs are requires a two part assembly operations.
·
They eliminate deviations from perfect squareness in
an assembly.
5.
In what
conditions the studs should be used in place of bolts?
·
For performance of heavy duty applications
·
The use of stud is preferred whenever possible instead
of main cap bolts, in those instances where a choice is available.
6.
Differentiate
between bolt and stud.
·
Bolt:Automotive Bolt is an
externally threaded headed fastener, which is used in conjunction with a nut.
·
Studs: Automotive studs are commonly referred to as
a double ended automobile fastener.
7.
Importance
of wheel stud.
ANS:Wheel studs are the threaded fasteners that hold on
the wheels of many automobiles. They are semi-permanently mounted directly to
the vehicle hub, usually through the brake drum or brake disk.
SESSION- 4: AUTOMOTIVE
WASHERS AND RIVETS
I. FILL IN
THE LANKS
1.
A washer is a thin platewith a hole that is
normally used to distributethe load of threaded fasteners.
2.
Automotive washers are the small flat dishes
having aholein
the center.
3.
Rivets are the oldest forms of automotive fasteners
used in building
traditional wooden boat.
4.
Rivets are usually categorized on the basis of
their heads.
5.
Circlips are often used to secure pinned connections.
6.
Split pins are typically made of shaft metal, making them easy
to install
and remove.
7.
Spring pins have a body diameter which is larger than the hole
diameter, and a chamfer on either one or both ends to
facilitate starting
the pin into the hole
II. Answer the following questions:
1. Describe the importance of washers.
ANS:A washer is a thin
plate (typically disk-shaped) with a hole (typically in the middle) that is
normally used to distribute the load of a threaded fastener, such as a screw or
nut. Washers usually have an outer diameter (OD) about twice the width of their
inner diameter (ID).
2. Describe the importance of rivets.
ANS:Rivets often regarded
as a semi-permanent mechanical fastener having a cylindrical shaft with head on
one hand and the end opposite the head is called buck-tail. Rivets are the
oldest forms of automotive fasteners used in building traditional wooden boat.
But now rivets are used as automobile fasteners in a wide number of
applications like vehicle bodies, aircraft, bridges, cranes, building frames
etc.
3. What are the advantages of using washers as
fasteners?
· To protect the surface
from damage during installation.
· They distribute the
pressure
· Prevent the fasteners
from moving.
4. In what conditions the rivets should be used
as fasteners?
ANS:Because there is effectively a head on each end of an
installed rivet, it can support tension loads however, it is much more capable
of supporting shear loads.
5. What are the advantages of using split pin
as fastener?
· A split pin washers
used to reduce friction between the split pin and the wheel.
· Split pin are strong
but after they can wear and break
6.
What are the
advantages of using spring pin as fastener?
·
The benefits of spring pin washer lies in the
trapezoidal shape of the washer.
·
This prevents loosening.
7.
·
Universal
·
Cone Head
·
·
Button Head
·
Truss Head
·
Pan Head
·
Flat Head
·
Flat top countersunk head
8. What are uses of circlip?
·
Circlips are commonly used in motors, turbines and
pistons.
·
Circlips fit into grooves on the inside of a bore or
outside of a shaft.
·
Circlips are often used to secure pinned connections.
9. Name different
types of washers.
*Fender,
split lock, dock, sealing, finishing etc.
10.
Name different types of rivets.
Types of rivets are: 1 universal, button head, pan
head, cone head, and trues head
SESSION-
5: REMOVAL OF DAMAGED FASTENERS AND REPLACEMENT
I. FILL IN THE BLANKS
- In automobile, due to jerk,vibration
andcorrosionscrews
get broken.
- Use hacksaw blade and dress the groove.
- In automobile, due to jerk movement and
vibration, nuts and bolt get loosened.
- A stud is stronger than a bolt,with correct stud
installation; the stud is screwed into the threaded hole without
applying pressure.
- Anti-rust solution are used for
dissolving the dust, rust from the fastener area.
II.Answer the following questions:
1.
Method to
remove screw with spoiled head.
·
Use hacksaw blade and
dress the groove
·
Now use screw driver
of thick snap and turn anticlockwise
·
This removes the
screw, if it is not responded
·
Take a prick punch and
hammer. Give light blow in anti-clock wise direction.
·
If it does not work
then use drill machine of drill bit smaller than size of screw
·
Now drill it at the center of screw, now 100% screw
will be removed
2.
Method to
remove screw without head/un headed.
·
If the screw is broken
at the top of the assembly
·
Remove the other screw
and separate the assembly
·
Hold the jaws of the
crippler on broken screw
·
Lock the crippler and
turn anti-clock wise & Screw may come out
3.
Method for
removal of UN headed screw broken in the assembly.
·
Use drill machine of
drill bit smaller than size of screw
·
Now drill it at the
center of screw, now 100% screw will be removed
·
Now dress the threads before fixing new screw
4.
Method of
removal of spoiled headed nut/bolts.
·
Use spanner of smaller
size, fix it on the nut/bolt and turn anti-clock wise It will come out
·
If it does not come
out, use prick punch.
·
Take a prick punch and
hammer at the face of nut/bolt. Give light blow in anti-clock wise direction.
·
If it does not work
then use drill machine of drill bit smaller than size of nut/bolt
·
Now drill it at the
center of nut/bolt an remove the edges of nut, in case of bolt remove the bolt
head by using crippler, remove the remaining part of the bolt from the
assembly.
5. Method of removal of broken/ spoiled
threaded studs.
·
To remove spoiled
threaded stud, give gentle pressure on assembly by using screw driver, this
will lift the spoiled portion of the stud threads upward.
·
Turn the nut in
anticlockwise, turn the stud assembly and gentle press the screw
·
driver inside so that
stud will come out
·
In case, if the nut
threads internal threads of the nut/external threads of the studs are spoiled,
then give welding spot to nut and stud
6. Importance of antirust solution.
ANS:Anti-rust solution are used for dissolving the dust,
rust from the fastener area. Use of this solution will make fasteners
comfortable during removal/changing process. Now days Indian as well as
imported antirust solution/spray are available in the market.
Use of anti-rust solution
Anti-rust
solution are used for dissolving the dust, rust from the fastener area. Use of
this solution will make fasteners comfortable during removal/changing process.
Now days Indian as well as imported antirust solution/spray are available in
the market.
UNIT 3 -
MEASURING INSTRUMENT
SESSION 1 – HANDLING AND USAGE OF DIRECT AND INDIRECT MEASURING INSTRUMENTS
I. FILL IN THE BLANKS.
1.
A measurement is
assigning a value to length, mass and time.
2.
The measuring instruments, which do not
require the help of otherinstrument for
measuring are called direct measuring
instruments.
3.
Steel scale/rule is a line measuring
device.
4.
The Vernier Caliper is a precision
instrument that can be used to measure internal and
external distances extremely accurately.
5.
In the Vernier caliper sliding jaw
containing the Vernier scale,
moves over the main scale.
6.
For measuring the depth of hole, recesses
and distance from a
plane surface to a projection, the Vernier depth gauge is employed.
7.
The micrometer is a precision measuring
instrument, used by engineers and technicians for inspectionand
measuring the distance between two faces.
8.
The digital micrometer displays the finalreading.
II. ANSWER
THE FOLLOWING:
- What
is measuring equipment?
ANS:Measuring
equipment are measuring tools they are to measure dimension of an object
Ex: calliper,
micro meter, gauges etc.
- Classify
the measuring instruments?
ANS:Measuring
instruments are classified in automobile field as follows:
1)
Liner measurements
2)
Direct measuring instrument ex:
steel scale screw gage.
3)
Indirect measuring instrumentex:
callipers inside and outside.
4)
Angular measuring
5)
Plane surface measurement
1. Make a list of direct and indirect measuring instruments
ANS:Direct measuring instruments:Ex: steel scale
screw gage
In-Direct measuring instruments:Ex:
callipers inside and outside
2. Importance of measuring instruments.
ANS:Important measuring
instrument used in our daily life. Similarly measuring instruments are also
used in automobile serviceability. These instruments help in measurement of
important dimensions of components.
Important measuring instruments used are Dial
gauge, Bore Gauge, Vernier caliper, Depth Gauge, Micrometer, Hydrometer and
Multi meter etc.
3. What is difference between direct and
indirect measuring instruments?
Direct
Measuring Instrument: The measuring instruments, which do not require the help of other
instruments for measuring, are called direct measuring instruments.
Usually a line measurement using scale
Ex: scale steel tape calliper etc.
In Direct Measuring Instrument:Indirect
measuring instruments are measuring instruments, they are used to measure the
dimension of an object indirectly,
Ex:
callipers, inside calliper, outside calliper
4. Describe the procedure for determining the
least count of Vernier caliper.
The Vernier scale consists of a main scale
graduated in centimeters and millimeters (in inches if there is imperial
scale).
Least count = one main scale (MS) division -
one vernier scale (VS) division.\
Suppose 10
division of Vernier scale = 9 division of main scale. Therefore one division of
Vernier scale = 9/10 = 0.9 mm of main scale division (one division of main
scale = 1 mm).
Therefore
the least count will be
= 1 mm - 0.9 mm
= 0.1 mm or = 0.01 cm
5. Describe the procedure for determining the
least count of micrometer.
Least Count (L. C) = Pitch/No. of divisions on
micrometer barrel (thimble) where, Pitch = distance travelled by thimble on
linear scale in one rotation, which is usually 0.5 mm unless stated. In the
examples below, the number of division on the barrel are 50. Therefore the least
count of the micrometer will be 0.5/50 = 0.01
Read the scale on the sleeve.
6. Describe the process for measurement with
indirect measuring instruments.
There are situations where direct measuring
instruments cannot be used. The simple calipers can be used in these
situations. For measuring, the object is held between the ends, object removed
and the ends are placed on steel scale to determine the distance. These
calipers can be used to measure the length, outside and inside diameters.
7. Differentiate between Vernier and digital
caliper.
Vernier Caliper:The meter
scale enables us to measure the length to the nearest millimeter only.
Automobile technicians need to measure much smaller distances accurately
Digital Caliper:it is
refinement or replacement of the analog dial with an electronic digital display
on which the reading is displayed as a single value.
8. Describe the parameters which can be
measured with Vernier depth gauge.
·
For measuring the
depth of holes, recesses and distances from a plane surface to a projection.
·
Write a short note on the following
*vernier calliper:
Vernier calliper
is a measuring tool commonly used to measure smaller distance an accurately.
*in vernier
calliper can measure length diameter inside and outside diameter of an object
*the vernier
calliper consist of a main scale and a fixed jaw and a movable jaw
·
Draw a neat diagram of vernier
calliper
SESSION 2 – ANGULAR MEASURING INSTRUMENTS
I. FILL IN
THE BLANKS
1.
Instruments used for measuring the angle
are called angularmeasuring
instruments.
2.
A protractor is a device for measuring the
angle between two intersecting lines.
3.
The blade protractor has double
graduations from 0 - 180° in opposite directions permitting the direct
reading of angles and supplementaryangles.
4.
A bevel gauge is an adjustable gauge for
setting and transferring angles.
5.
The universal bevel protractor is designed
for precision measuring
and layout of
angles.
II. ANSWER THE
FOLLOWING:
1. Make a list of angular measuring instruments
·
Protractor
·
Blade Protractor
·
Bevel or Combination
·
Universal Protractor
2.
Importance
of angular measurement and measuring instruments.
ANS:Instruments used for measuring the angle are
called angular measuring instruments.
3.
What is
difference between protractor and blade protractor?
Protractor:A protractor is a device for measuring the
angle between two intersecting lines.
Blade Protractor:This is a highly
useful and accurate tool for setting bevels, transferring angles, small
squaring tasks, and many other applications.
4.
Describe the
procedure for using the bevel gauge/combination gauge.
·
A bevel gauge is an adjustable gauge for
setting and transferring angles. The handle is usually made of wood or plastic
or steel and is connected to a metal blade with a thumb screw,the blade pivots
and can be locked at any angle b loosening or tightening the thumb screw.
·
Gauge is mainly used to measure of angle of valve face.
The straight edge is used to check the cylinder head, cylinder block
5. Importance of universal bevel protractor.
·
The universal bevel
protractor picks up where the blade protractor leaves off. The universal bevel
protractor is designed for precision measuring and layout of angles.
·
The universal bevel
protractor is capable of measuring obtuse angles as well as acute angles
SESSION 3 – DIAL INDICATOR/GAUGE AND OTHER GAUGES
I. FILL IN THE BLANKS
1. Dial gauge is used as
a measuring device to measure the accuracies in alignment,
eccentricityof the parts/components.
2. Dial gauge works on
the rackand
pinion
principal.
3. A telescoping gauge is a measuring tool with
spring-loaded plunger used together with
a micrometer to measure the inside of holes or bores.
4. A Vernier bore gauge
measures a bore directly.
5. A dial bore gauge is a
special tool, which is used to accurately measure the inside diameter of
a hole, cylinder or pipe and will also detect ovality and tapers in bores.
6. Screw pitch gauges are
used to check the pitch of the thread immediately.
7. Feeler gauges are used
for checking the clearance between mating surfaces
II. ANSWER
THE FOLLOWING:
1. Various
types of gauges are used for checking components of automobile. Make a list of
these gauges
·
Dial gauge, Digital Dial Gauge, Telescopic gauge, Bore
Gauge, Screw Pitch gauge,Feeler Gauge
2. Importance of dial indicator/gauge and other
gauges.
·
It is used as a
measuring device to measure the accuracies in alignment, eccentricity of the
parts/components.
·
Dial indicators are
also great for checking crankshaft run out, crank end play, shaft thrust, and
gear backlash, flywheel face run out,
·
A dial gauge is like a fine watch. It consists of a
graduated dial, pointer, plunger and a clamp.
·
It measures the displacement of its plunger on a
circular dial by means of rotating pointer.
3. Describe the working principle of dial
gauge.
It works on the rack and pinion principle. A dial gauge is like a fine watch. It consists
of a graduated dial, pointer, plunger and aclamp. It measures the displacement
of its plunger on a circular dial by means of a rotating
Pointer.
4. Describe feeler gauge and its application.
·
Feeler gauges are used
for checking the clearance between mating surfaces.
·
They are mainly used in adjusting the valve clearance
and setting of spark plug gaps in automobiles.
·
They are made from 0.03to 1.0mm thick of 100mm long
leaves. The blades are pivoted in a holder.
To know or adjust the clearance/ gap, the leaf of the feeler
gauge is selected and insertedin
the gap, the leaf should not be loose or inserted with force. The leaf
should go in the gap with slight drag/resistance. The value of the
clearance/gap is read from the leaf offeeler gauge.
5. Importance of telescopic gauge
·
A telescoping gauge is
a measuring tool with spring-loaded plungers used together with a micrometer to
measure the inside of holes or bores.
·
Telescopic gauge is
used to find out the internal diameter of pipe, cylinder bore and slots.
·
This gauge has ratchet
locking at top, handle, body and telescopic operated plungers
·
A telescoping gauge is
an indirect measuring device,
6. Importance of Bore gauge.
·
A dial or Vernier bore
gauge measures a bore directly. The gauge has three symmetrical anvils that
protrude from the gauge body that are connected to the dial or micrometer
mechanism.
7. Importance of dial bore gauge
·
A dial bore gauge
(Fig-21) is a special tool, which is used to accurately measure the inside
diameter of a hole, cylinder or pipe and will also detect ovality and tapers in
bores.
·
Dial-bore gauges are useful in checking for taper or
out-of-round conditions in a cylinder bore as well as many other inside
machinists measurements. In conjunction with a micrometer, a bore gauge will
give the exact reading of a bore size.
8. Describe screw pitch gauge and its
application.
·
Screw pitch gauges are
used to check the pitch of the thread immediately. It is very much in everyday
tool used to pick out a required screw.
SESSION 4 – INSTRUMENTS ON THE DASH BOARD OF A VEHICLE
I. FILL IN THE BLANKS
1. The speedometer tells the driver the speedof
a vehicle.
2. Tachometer tells how fast engine is turning in
revolution
per minute(rpm).
3. An odometer is an instrument that indicatesdistancetraveled
by a vehicle.
4. The fuel gauge informs abut status of the amount
of fuel in the tank of vehicle.
5. The temperature gauge doesn’t actually measure
the temperature of your engine; instead, it measures the temperature of
engine’s coolant.
6. An automotive navigation system is a satellite
system designed for use in automobiles.
II. ANSWER THE FOLLOWING:
1. List the important instruments which are
fitted on a dashboard of a vehicle.
·
Speedometer,
·
Tachometer,
·
Odometer and
·
Fuel gauge, and
·
Indicators such as
gearshift position,
·
Seat belt warning
light,
·
Parking-brake-engagement
warning light and an
·
Engine-malfunction
light.
·
Low fuel, low oil
pressure,
·
Low tire pressure and
·
Faults in the airbag
(srs) system.
·
Heating and ventilation controls and vents,
·
Lighting controls,
·
Audio equipment and
·
Automotive navigation systems
2. Importance of instruments on the dash board.
·
A dashboard can be
considered as a control panel placed in front of the driver on which he keeps
an eye for proper functioning of the vehicle.
·
The dashboard has
cluster of instruments and gauges which convey the health of vehicle to the
driver.
3. What information is given by the
speedometer?
The speedometer tells the driver the speed of
a vehicle whether he is driving fast or slow or within specified speed limit.
Speed is measured in kilometers per hour.
4. What information is given by the odometer?
An odometer is an instrument that indicates
distance traveled by a vehicle. The device may be electronic, mechanical, or a
combination of the both. The device is helpful to know the distance covered
between two destinations.
5. What information is given by the Tachometer?
Tachometer tells how fast engine is turning in
revolutions per minute (rpm). Driver should avoid running engine so hard like
“danger zone” as indicated on the tachometer.
6. What information is given by the fuel gauge?
The fuel gauge informs about the amount of
fuel in the tank of vehicle. If you don’t keep an eye on your fuel gauge, you
could run out of fuel. We should regularly check the fuel gauge so that we are
not stranded at road due to absence of fuel.
7. What information is given by the temperature
gauge?
·
The temperature gauge
doesn’t actually measure the temperature of your engine. Instead, it measures
the temperature of engine’s coolant.
·
It’s important to get an idea of how hot car typically
runs.
8. What information is given by the malfunction
indicator lamp?
·
A malfunction
indicator lamp (MIL), also known as a check engine light, is a tell-tale to
indicate malfunction of a computerized engine management system.
·
It is found on the
instrument panel of most automobiles. When illuminated, it is typically either
an amber or red color.
·
The malfunction indicator lamp usually bears the
legend CHECK ENGINE, SERVICE ENGINE SOON.
9. What is the use of navigation system in automotive
vehicles?
·
An automotive
navigation system is a satellite navigation system designed for use in
automobiles.
·
It typically uses a
GPS navigation device to acquire position data to locate the user on a road in
the unit's map database.
·
Using the road
database, the unit can give directions to other locations along roads also in
its database.
·
Various companies
manufacture this unit and same can be fitted in dashboard of vehicle.
10. What is the use of driver information
system?
Now days most of the vehicles are fitted with
DIS System. This system enables driver about various information such as
spontaneous fuel consumption, range of travel, available quantity of fuel in
terms of kilometer, digital watch with atmospheric temperature.
UNIT 4 - SERVICEABILITY, REPLACEMENT OR REPAIR OF
ENGINE COMPONENTS
SESSION 1:
RECONDITIONING OF VALVE MECHANISM
I. FILL IN THE BLANKS
1. A poppet valve is a valve typically used to
control the timing and quantity of gas or vapor flow into an engine.
2. In overhead valve mechanism (OHV) the camshaft
is fixed in the crank case.
3. In overhead cam mechanism (OHC) the camshaft
is fixed in the cylinder head.
4. To overcome leakages of combustion gases,
valve reconditioning
is required.
5. Remove the valves using a valve spring
compressor, observe the valve leakage.
6.
Measure the angle of valve seat with help of bevel
protractor.
II. ANSWER THE FOLLOWING:
1. Make a list of reasons for valve leakage in
a vehicle.
If the combustion gases leaks from valve, then
it may cause
·
Excessive fuel
consumption
·
No pickup
·
Engine do not take
load
·
Hard starting
·
Valve sticks
·
Engine overheats
2.
What is
poppet valve? Orwhat is the purpose of a valve?
A poppet valve is a
valve typically used to control the timing and quantity of gas.Or vapor flow
into an engine.
3.
How many
kinds of valve used in IC Engine?
Two types of valves used in engine are inlet valve and
exhaust valve.
4.
Briefly
describe a function of a valve & draw its line diagrams with details?
Functions
·
To control the timing
and quantity of gas or vapor flow into an engine.
·
To take the air fuel
mixture into the cylinder and expel the exhaust gaseous.
5.
What are the
seat angles & why it is required?
ANS:Valve seat angle is
related to both engine breathing performance and valve seat wear
durability. Because, they are used to
regulate the flow of liquid, gases, steam, vacuum and even aggressive fluids.
6.
Which part
control opening & closing of a valve?
ANS:Camshaft consists of
several parts like camshaft journals, cam lobes.
7.
What are the
uses of valve mechanism and lit the types?
It controls submission of inlet gases and emission of
exhaust gases at right time in relation with rotation of cam shaft. Valve
mechanism are classified as given below
1. Overhead valve mechanism (OHV)
2. Overhead Cam
mechanism (OHC)
8.
What are
main difference between overhead valve mechanism and overhead cam mechanism?
Overhead valve mechanism (OHV): It consist of inlet valve, exhaust valve, valve
guide, valve spring lock, valve seat, push rod, and rocker arm and rocker
shaft. In this case camshaft is fixed in the crankcase.
Overhead Cam mechanism (OHC): It consist of inlet valve, exhaust valve, valve
guide, valve spring lock, valve seat, valve spring, rocker arm, and rocker
shaft. In this case camshaft is fixed in the cylinder head.
9.
Why
reconditioning of valve is necessary and write the procedure?
To overcome leakages
of combustion gases, valve reconditioning is required.
·
Dismantle the cylinder
head from the engine.
·
Remove the carbon from
the head, and piston head.
·
Clean the piston head.
·
Add little quantity of
precision blue in petrol and with the help of dropper, put the mixture on the
valve face.
·
Remove the valves
using a valve spring compressor, observe the valve leakage.
·
Blue color shows
leakage area.
·
Clean the valves with a wire brush
10. Write the name of the tools required for
valve seat grinding?
·
Bevel protractor * Grinder *Cutter.
11. Write the procedure for resurfacing the
valve.
§ Inspect the valve run out if it is more than 2
degree
§ Inspect the valve margin if it is less than 2
mm then it is necessary to replace the valve
§ Place the valve on valve resurfacing machine.
§ Set the machine at the angle between 35 to 45
degree,
§ Start the machine,
§ Open the coolant
supply and start resurfacing operation slowly.
12. Write the procedure for valve seat cutting
and grinding operations.
·
Measure the angle of
valve seat with help of bevel protractor,
·
Check the margin of
valve seat, If it is less than 2 mm replace the valve seat.
·
If it is more than 2mm
then it is suggested to carryout valve seat grinding operation,
·
Select grinder/ cutter
of appropriate size and angle,
·
Fix the holder and
pilot to the grinding stone/cutter,
·
Now grind the valve
seat with machine or manually and cut the valve seat to get required angle.
13. Write the procedure for valve lapping
operations.
§ Select the valve lapping stick of proper size,
§ Place its rubber hide on the valve face,
§ Apply abrasive/emery coarse paste on the valve
face,
§ Now turn the lapping stick in to clockwise and
anticlockwise direction, this will lap valve with valve seat.
SESSION 2:
REPLACEMENT OF PISTON RINGS
I. FILL IN THE BLANKS
1.
A piston ring is a
split ring which fits into a grooves of an internal combustion engine or
steam engine piston.
2.
Most automobile engine
piston has three
rings.
3.
Compression ring withstands for more pressure
and temperature.
4.
Piston rings expandand
contract
during compression and exhaust stroke.
5.
Two compression rings
are used in most of the internal combustion engine.
6.
Piston rings transfer
heat from the piston to the cylinder wall.
7.
Oil ring is also replaced
when oil enters in combustion chamber and there is increasein the consumption of
oil.
II. ANSWER THE FOLLOWING:
1.
Make a list
of steps required to measure the clearance between piston and cylinder wall.
§ Place the vehicle on level ground.
§ Remove the negative terminal of the battery.
§ Keep a tray below the engine.
§ Take the spanner and remove the drain plug.
§ Allow all the oil to flow out of the engine
into the tray and keep the tray aside.
§ Remove the connection of radiator hoses, pipe
from water pump also.
§ Take out the radiator by unscrewing the nuts/bolts.
§ Take out the fan, and then remove the belt
from pulley.
§ Dismantle the water pump and keep aside.
§ The alternator, starter motor is not necessary
to remove out, keep it aside on the chassis.
§ Then from underneath remove the nut of the
sump using ring spanner.
§ Remove the oil sump.
§ Then remove the tapped cover.
§ Now remove the induction manifold.
§ Using 14-15 ring spanner remove the connection
of fuel line pipe and keep aside.
§ Then remove the engine
heater connection and lose the heaters.
2.
How many
types of rings used in piston?
ANS:Three rings (Two
Compression Ring and One Oil Ring).
3.
How much the
clearance provided in the cylinder bore?
ANS:The minimum clearance
provided in the cylinder bore is 54.02mm.
4.
What is the
function of compression rings?
ANS:The main function of
compression ring is to trap combustion gases and increase the combustion
pressure and efficiency.
5.
What is the
function of oil control ring?
ANS:To control the supply
of oil to the cylinder wall and in order to lubricate the piston skirt and oil
control ring.
6.
What is the
position of the ring in the piston?
ANS:Two rings (Compression
Rings) are positioned near to TDC and One Ring (Oil Ring) is positioned near to
BDC.
7.
How to check
the end gap, side gap and piston clearance?
END GAP
·
Take the piston ring and place it in cylinder bore at
TDC.
·
Align and level the piston ring with the help of
piston.
·
Take the feeler gauge and slide it in place between
the end gaps of the ring.
·
Take the micrometer and measure the feeler gauge.
·
Note the reading.
SIDE GAP
·
Take the piston and piston ring.
·
Take any one piston ring on the ring groove with
feeler gauge.
·
Then take the micrometer and measure the feeler gauge.
·
Note down the reading.
PISTON CLEARANCE
·
Take the piston out from the respective
cylinder.
·
Place the piston in the respective
cylinder bore with feeler gauge.
·
Use micrometer to measure the feeler gauge
thickness.
·
The measured thickness is known as piston
clearance.
SESSION 3:
INSPECTION AND REPLACEMENT OF CYLINDER LINER/
BORE
SLEEVE, CONNECTING ROD AND ENGINE BEARING
I. FILL IN THE BLANKS
1. Always replace the
bend or twistconnecting
rod.
2. Turn the crank shaft,
if run out is noticed more than 0.06mm, then it is need to regrind the crank
shaft.
3. The permissible value
of ovality is 0.01mm to 0.015mm.
4. The permissible value
of tapernes is 0.01mm to 0.015mm.
II. ANSWER THE
FOLLOWING:
1.
Make a list of steps required for
inspection and replacement of cylinder liner/ bore sleeve.
§ Place the engine block
on the press.
§ Use special tool as
per the size of cylinder bore.
§ Support the engine
block properly and rigidly fix on the press.
§ Apply pressure of 0.2
to 0.5 tone for dry liner of B.D.C.
§ The old sleeve will
come out from engine block
§ Select new standard
size bore sleeve with standard piston and rings.
§ Place the sleeve in
liquid hydrogen where it will become easy to place in the engine block bore.
§ Place the sleeve on
the engine block from the cylinder head side.
§ Operate the press
slowly with pressure of 0.1 to 0.3 tone the sleeve will easily enter in the engine
block.
§ Inspect the height of
the sleeve in engine block with machinist edge and feeler gauge.
§ Maintain equal height
for all cylinders.
§ Clean and lubricate
the bore
§ Check piston clearance
with the help of feeler gauge..
§ Repeat the same for
all sleeves.
2.
What is the function of connecting
rod?
Connecting rod is an
engine component that transfers motion from piston to the crank shaft and
functions as a lever arm.
3.
Why do some connecting rod have hole
drilled from small end to the big end bearing?
Because small end
bearing is connected to piston with the help of piston pin and big end bearing
is connected to crankshaft with the help of gudgeon pin.
4.
Which part is connected to the small
end of the connecting rod?
Piston Pin
5.
Which part of connecting rod is connected
with crankshaft?
Big end bearing
6.
How to check bend in connecting rod?
To check the bend in
connecting rod with the help of a rod checker (Rod Alignment) and Twist checker
7.
How to check clearance between
connecting rod and crankshaft?
Feeler gauge and Micro meter
SESSION 4:
TESTING OF COOLING SYSTEM AND REPLACEMENT OF
DEFECTIVE
COMPONENTS
I.FILL IN THE BLANKS
1.
In I.C. engine during power stroke, the
engine temperature reaches between 700 to 900 oC.
2.
In a vehicle, most of the energy of fuel
(approx. 70%) is converted into heat, and it is
the job of the cooling systemto take
care of that heat.
3.
The primary job of the cooling system is
to keep the engine from overheating by transferring this heat
to the air.
II. ANSWER
THE FOLLOWING:
1. Make a list of common faults in cooling
system
·
Loose or broken water pump pulley
·
Low level of coolant
·
Faulty thermostat
·
Faulty water pump
·
Faulty radiator cap
·
Coolant leakage on cooling system
·
Defective cooling fan motor
·
Improper Ignition timing
·
Faulty Thermostatic switch
2.
Why the
cooling system is important in I C Engine?
The primary job of the cooling system is
to keep the engine from overheating by transferring this heat to the air.
3.
Name the
different component of cooling system
·
Radiator*Cooling Fan*Thermostat *Reserve
Tank*Water
Pump*Pressure
cap*Hoses
4.
Name the
different methods of engine cooling.
·
Air cooling
·
Water cooling
·
Liquid cooling
·
Pressure sealed cooling
5.
Difference
between oil cooling system and water cooling system.
Oil cooling
system:Oil cooling is the use of oil as a coolant, typically
to removes surplus heat from an internal combustion engine.
Water
cooling System:Water cooling system
is a system used to supply water from radiator to engine water jacket to
maintain optimum temperature.
6.
What is the
function of radiator in cooling system?
The radiator transfer the heat from the fluid
inside to the air outside, which in turn cool the engine and also cool
automatic transmission fluid.
7.
Why coolant
is added in the radiator?
The purpose of coolant is to add to absorb the
excess heat from the engine part and carry it via passageways and tubes to the
radiator where the excess heat release to the atmosphere.
8.
What is the
function of thermostats?
The function of
thermostat is to control the temperature difference between engine and
radiator.
9. What is the function of water pump and
cooling fan?
Water Pump:The function of water pump is to push coolant
through the engine block, radiator and hoses to get the engine heat away from
the system.
Cooling Fan: The cooling fan is temperature controlled to
only run when needed.
SESSION 5: REGULAR
SERVICING OF MPFI SYSTEM
I. FILL IN THE BLANKS
1.
Sensors sense different parameter of the engine and
send signal
to ECM.
2.
Actuators receives control signal from ECM and does functionaccordingly.
3.
Processor collects all the data from sensor
and process,
takes appropriate decision.
4.
The function of ECM is to receive signal from various sensor,
manipulate the signals and send control signals to the actuators.
5.
MPFI system is also called motronic engine management
system.
II. ANSWER THE FOLLOWING:
1.
Make a list
of advantages of MPFI system
·
More uniform Air-Fuel
ratio will be supplied to each cylinder, hence the difference in power
developed in each cylinder is minimum.
·
No need to crank the
engine twice or thrice in case of cold starting as happens in the carburetor
system.
·
Immediate response, in
case of sudden acceleration / deceleration.
·
Since the engine is
controlled by ECM* (Engine Control Module), more accurate amount of A/F mixture
will be supplied and as a result complete combustion will take place.
·
The mileage of the
vehicle will be improved.
2.
What is the
full form of MPFI?
MPFI – Multi Port Fuel Injection
3.
What are
main components of MPFI?
ECM, Sensor, Actuators
and Processor
4.
What are the advantages of MPFI over
Conventional System?
·
More uniform Air-Fuel ratio will be supplied to each cylinder;
hence the difference in power developed in each cylinder is minimum.
·
The mileage of the vehicle will be improved.
5.
What are the disadvantages of MPFI
over Conventional System?
Inthis system each cylinder has number of
injectors to supply/spray fuel in the cylinders as compared to one injector
located centrally to supply/spray fuel
6.
What precaution to be taken while
working on MPFI system?
·
Always remove wire from spark plug.
·
Do not check for spark with spark plug removed
·
Do not tamper with springs.
·
Do not modify this system in any way.
·
Ensure that all the fuel and oil has been removed from
the engine.
7.
What is Sensor?
Sensing different parameters (Temperature,
Pressure, Engine Speed etc.) of the engine and send to ECM. Some of the important sensor are
crank angle sensor (CKP), cam sensor, throttle position sensor, AMF (Air mass
flow) sensor, coolant temperature sensor, oxygen (lymda) sensor etc.
8.
What is Actuator?
Receives control signal from ECM and does
function accordingly. (ISCA, PCSV, Injectors and Power Transistor etc.)
Important actuators are fuel injector, immobilizer unit, body control module,
motorized headlight, fuel pump etc.
9.
What is ECM?
The function of ECM is to receive signal from
various sensors, manipulate the signals and send control signals to the
actuators.
10. Write the two name of sensor used in MPFI?
Cam sensor and coolant temperature sensor
11. Write the importance of throttle body.
Throttle body is very important part of air
supply system to the engine. It should be regularly cleaned. Due to carbon
deposit inside the throttle valve and backfire. Throttle body (Butter fly) can
be cleaned by carbo cleaner.
SESSION 6:
CRDI AND NON CRDI SYSTEM
I. FILL IN THE BLANKS
1.
In common rail fuel injection system a single injection
pump with injector called as unit injector is employed on each.
2.
In individual pump fuel injection system
fuel is drawn from the fuel tankby means
of fuel feed pumpwhich is
operated from the injection pump camshaft.
3.
To inject the fuel in the cylinderin
properly, atomized form and in proper quantity, fuel injector nozzleis used.
4.
Nozzle consist of small hole which
helps insprayof the
fuel.
5.
A turbo charger or turbo is a forced injection device
used to allow more power to be produced by anengineof a given
size.
6.
Turbo chargers are popularly used with
petrol and diesel internal
combustion engines.
II. ANSWER
THE FOLLOWING:
1.
Make a list
of components of CRDI system
·
Storage of
fuel( Fuel tank)
·
Filtering
of fuel(Fuel filter, sedi meter)
·
Delivery
of fuel to injection pump (Primary pump)
·
Injecting
the fuel into engine cylinder(rail assembly, unit injector, high pressure pump)
·
Controlling the engine speed (ECM
operated)
2.
What is the
full form of CRDI?
CRDI -
Common Rail Direct Injection
3.
What are the
Advantages of CRDI over Conventional Diesel system?
·
Reduced noise and vibration
·
Reduced smoke, particulate and exhaust.
·
Increased fuel economy
·
Higher power output even at lower RPM
4.
What are the
disadvantages of CRDI over Conventional Diesel system?
·
High cost due to high pressure pump & ECU
·
Technology cannot be employed in present engine
5.
What
precaution to be taken while working on CRDI system?
·
Smokes anywhere near an engine with suspicion of a
diesel tank.
·
Do not carry out repairs until fuel injection pressure
has dropped to zero.
·
Do not carry out repairs to injection equipment with
engine running
·
Always consult vehicle dealers if any doubt as to
correct procedure.
6.
List the
types of CRDI.
Common Rail Fuel Injection system: In this
type of system a single injection pump with injector called as unit injector is
employed on each cylinder. These unit injectors are operated by rocker arms
& springs similar to engine valves.
Individual
Pump Fuel Injection system:In this
system fuel is drawn from the fuel tank by means of fuel feed pump which is
operated from the injection pump cam shaft. The fuel injection pump then
injects definite quantity of fuel into individual cylinders according to firing
order through injectors fitted on them. It is also known Non CRDI system.
7.
Explain the
use of fuel injector nozzle
To inject the fuel in the cylinder
in properly,atomized form and in proper quantity, fuel injector nozzle is used.
Nozzle consist of small holes which help in spray of the fuel.
8.
Explain the
use of turbo charger.
Turbo Charger: A turbo
charger or turbo is a
forced induction device used to allow more power to be produced by an engine of
a given size. A turbocharged engine can be more powerful and efficient than a
naturally aspirated engine because the turbine forces more air (oxygen), and
proportionately more fuel, into the combustion chamber than atmospheric
pressure alone.
9.
How to Servicing of turbo charger?
Normally turbochargers are working at 150000
rpm. Servicing of turbocharger is not recommended by the manufacture but if the
oil seal failure occurs than complete turbocharger assembly is replaced.
Precaution to be taken not came across dust entry while disassembly of
turbocharger
UNIT – 06
SUSPENSION
SYSTEM
SESSION 1: MAINTENANCE OF
SUSPENSION SYSTEM
I.FILL IN THE BLANKS
1.
The shock absorbers on a vehicle go
through as many as one thousandmovements
per kilometer.
2.
The springs support the weight of
vehicle act as a flexible link that allows the body and frame to ride with
minimal disturbance.
3.
Suspension keeps the vehicles tyres in
contact with the road surface.
4.
Suspension is very important to the safety and performance of
vehicle.
5.
Most of the suspension parts are made of rubber material
to minimizeshocks.
II. ANSWER
THE FOLLOWING:
1. Make a list of important functions of suspension system of a vehicle.
·
Maintaining
the correct vehicle ride height
·
Reducing
the effect of shock forces to the vehicle
·
Maintaining
the correct wheel alignment
·
Supporting
the vehicles driving stability
·
Keeping
the vehicles tyres in contact with the road
·
Control of
vehicle’s direction of travel.
·
Maintain
the centre of gravity, when vehicle is moving.
2.
Why is suspension system required in
a vehicle?
The function of keeping the tyres evenly
connected with the road and maintaining a vertical load on the tyres.
3.
Name different components of a
suspension system?
Vehicle’s suspension system is made up of
four basic components namely the struts, shock absorbers, springs and tyres.
4. Make a list of maintenance tips for suspension system.
·
Thoroughly
clean the leaf spring set and its fittings,
·
With the
help of grease or pneumatic grease gun, lubricate all shackle pins, swing arm
of the leaf spring set,
·
Lubricate
each leaf with graphite grease,
·
Tighten
the u clamp bolts /nuts with specified torque,
·
Check the
centre bolt,
·
Tighten
the clamp nut bolt with specified torque,
·
Check the
slackness of shackle and tighten the set if needed
·
In case of
shock absorber/stud, tighten the holding nuts and bolts at both ends
·
In case of
two wheeler, tighten the swinging of nuts/bolts of front and rear wheels,
·
Avoid
overloading vehicle.
·
Avoid
sudden acceleration and breaking.
5. How to Servicing of suspension system
The shock absorbers on a vehicle go
through as many as one thousand movements per kilometer so it is not surprising
that they wear out quite quickly and should be checked every 20,000 kilometers
during major servicing.
SESSION 2:
SERVICE AND REPLACEMENT OF LEAFS, CAMBERING OF LEAF
SPRINGS,
SHACKLE, SHACKLE PIN AND CENTRE BOLT
I.FILL IN THE BLANKS
1.
A leaf spring is a simple form ofspringcommonly
used for the suspension in wheeled vehicles.
2.
A leaf spring takes the form of a slender
arc-shaped length of spring steel of
rectangular cross-section.
3.
Leaf springs can serve locating and to
some extent damping as well
as springing functions.
4.
The leaf spring acts as a linkage for
holding the axle in position and thus separate linkage are not
necessary.
5.
Cambering helps to reduce the flexibility of
spring.
6.
A spring shackle is a device found on
leaf-spring equipped vehicles.
7.
Centre bolt holds the bunch of leaf
together to bear theshocks.
II. ANSWER THE FOLLOWING:
1.
Why leaf springs are provided in
vehicle, state its functions?
·
The leaf
spring acts as a linkage for holding the axle in position and thus separate
linkage are not necessary. It makes the construction of the suspension simple
and strong.
2.
Sate the role of leaf spring in a
vehicle?
·
As the
positioning of the axle is carried out by the leaf springs so it makes it
disadvantageous to use soft springs i.e. a spring with low spring constant.
·
The
inter-leaf friction between the leaf springs affects the riding comfort.
3.
Describe the functions of shackle.
·
To allow
different mounting heights.
·
The
shackles allow for movement of the suspension by pulling in or pushing out as
the suspension travels through its up and down cycle.
4.
Describe the functions of center
bolt.
It holds the bunch of leaf
together to bear the shocks. If it is broken, it will leads to vehicle pull to
one side, It is necessary to replace immediately.
5.
What tools
and equipment are required for servicing of leaf spring system.
Chassis jack/hydraulic jack, screw
jack, supporting stands, Socket spanner set, Open end spanner, DE ring spanner,
spring clamp, anvil, hammer
6.
What is
meaning of leaf spring?
A leaf spring is a simple form of
spring commonly used for the suspension in wheeled vehicles, sometimes referred
to as a semi-elliptical spring or cart spring, it is one of the oldest forms of
springing, dating back to medieval times.
7.
What is
meaning of shackle?
A spring shackle is a device found
on leaf-spring equipped vehicles. The spring shackle mounts to one end of the
leaf spring and allows it to flex and move while keeping the tire on the road.
8.
List the
precautions to be taken while servicing, maintenance and repair of leaf spring.
·
Fix the
spanners properly.
·
Use
special jack and the stand to support the spring.
·
While
disassembling the leaf spring, fix it on the vice and disassemble it.
·
Place the
every nut/bolts properly in the tray.
·
Support
the chassis and axle with stand before removing it from the chassis.
·
Tighten the nut/bolts to the specified
torque.
9.
Make a list
of steps to carry out the servicing, maintenance and repair of leaf spring.
·
Keep the vehicle on plane hard surface.
·
Disconnect the negative terminal from the
battery.
·
Take the stand and support the chassis at
appropriate height.
·
Take the stand and support the axle/axle
beam.
·
Using appropriate spanner loosens the nuts
and removes the ‘U’ clamp bolts.
·
Remove the shackle pin from the chassis
fixed end.
·
Slowly dismount the spring assembly set
from the chassis.
·
Take the leaf spring set and place it on
the workbench.
·
With proper precaution, place the leaf
spring in the spring vice and remove the Centre bolt.
·
Separate the spring leaves and place it in
proper order.
·
Clean the leaves thoroughly.
SESSION 3:
REPLACEMENT OF STRUT/SHOCK ABSORBERS, INSPECTION OF STEERING LINKAGES
I.FILL IN THE BLANKS
1.
A shock absorber is a mechanical device
designed to smooth out or dampshockand
dissipateenergy.
2.
Suspension system has damper withspring.
3.
Every shock up/suspensionhas its
own life.
II. ANSWER THE FOLLOWING:
- Make a list of steps to carry out the
testing of shock absorber off the vehicle.
·
Keep the
vehicle on level ground
·
Jack up
the vehicle at the certain height to make the wheel free to rotate
·
Loosen the
wheel nut and remove out the front wheel
·
Remove
brake drum with bearing from stub axle by using hub puller
·
Remove the
brakes pins/ bolts from strut bracket
·
Remove the
strut bracket bolts
·
Remove
support nuts by supporting the strut properly
·
Dismount
the strut assembly from the vehicle
·
Use a
spring compressor to remove the strut spring
·
Fix the
spring compressor on the strut and compress the spring
- Make a list of steps to carry
out the testing of shock absorber on the vehicle.
1.
Keep the vehicle on the level ground,
2.
Press the front portion of the car with
gentle pressure,
3.
Now feel resistance in the up and down
movement of front portion,
4.
If notice any jerking movement, indicates
defect in shock absorber,
5.
Release the pressure and experience,
upward movement with same resistance,
6.
If it feels hard, noisy and stucked
/binding at any movement indicate faulty shock up.
7.
Visually inspect the shock up for fluid
leakage if found, replace it
- Describe the uses and applications of
shock absorbers?
To reduce the effect of traveling
over rough ground, leading to improved ride quality and vehicle handling. Every
shock up/suspension has its own life.
- Sate the reasons which affect life span
of shock absorbers?
·
Overloading
·
Road
conditions
·
Worn-out
Linkage/bushes
·
Leakage of
fluid/gas
·
Broken
casing
·
Deterioration
of Bump stopper
·
Rubber
bellows
·
Improper handling in service
- What tools and equipment are required for
servicing of shock absorber.
·
Open end spanners, ring spanner, tubular
spanner, locking clamps, screw drivers etc.
·
Oil, grease, metal tray, bolts waste,
equivalent parts etc
SESSION 4:
INSPECTION OF STEERING LINKAGE
I.FILL IN THE BLANKS:
1.
A steering linkage is the part of an
automotive steering system that connects to the front wheels.
2.
Regular Inspection of steering linkage is
necessity to maintain safety and control the
vehicle.
II. ANSWER
THE FOLLOWING:
1.
Make a list
of steps to carry out the inspection of steering linkages
·
Lift the front portion of the car/vehicle,
·
Turn the steering wheel from one lock end
to another lock end,
·
Check for noise and binding in-steer.
·
If the binding is traced, remove the drag
link connection from steering gearbox.
·
Now rotate the steering wheel in both the
direction and trace for the binding. If the binding is noticed then it probably
lies in the steering gear box.
·
If the binding is not traced in steering
gear box then problem is in steering linkage.
·
Inspect the ball joint if it is worn out
or bellow torned then replace it.
·
Inspect the bushes of the torsion bar and
replace it.
·
Inspect the draglink, tie rod for its straightens.
·
Remove the bush by using special tool and
replace the same.
2.
Make a list
of precautions to be taken while inspection of steering linkages
·
Fix the spanner properly.
·
Keep the removed nut bolts properly.
·
Handle the pots carefully.
·
Support the chassis properly with stand.
3.
What is
meaning of steering linkage?
A steering linkage is the part of
an automotive steering system that connects to the front wheels. Steering
linkages consist of drag link (pitman arm), tie rod, ball joint, end joint, arm
assembly, torsion bar, and steering shock absorber, bushes of steering axis,
steering arm and stub axle.
4.
What are
functions of steering linkages?
The function of steering linkage is to
maintain safety and control of the vehicle.
SESSION 5: MANUAL AND POWER
STEERING SYSTEM
I. FILL IN
THE BLANKS
1.
Rack and pinion type of steering gear is
used for lightvehicles
and in power steering.
2.
In hydraulic operated power steering,
fluid is pressurized through a
centrifugal pump.
3.
The centrifugal pump is driven by the
engine crankshaft through v
belt.
4.
EPS uses as electric motorto assist
the driver of the vehicle.
5.
Air suspension is a type of vehicle
suspension powered by an
electric or engine driven air pumpor
compressor.
6.
The purpose of air suspension is to provide a smooth,
constant ride
quality and in some cases it is self-leveling.
II. ANSWER
THE FOLLOWING:
1. In automobile different types of steering
are used. Make a list of types of steering.
·
Worm and roller
shaft
·
Worm and
nuts
·
Rack and
pinion
·
Worm and
sector
2. Make a list of steps followed for servicing
of rack and pinion type of steering.
·
Conduct
the road test and mark the central or the mid position of the road wheels
·
and the
steering gear box,
·
Raise the
front portion of a car and turn the steering wheel,
·
To check
for the binding in the steering,
·
If binding is traced then the fault is in
the steering gear box, and need to service
·
the steering gear box,
·
Disconnect the electric connections from
the steering wheel,
·
Using specified spanner remove the
steering wheel nut from the steering shaft,
·
Use special tool to remove the steering
wheel,
·
Remove the steering gear mounting bolts
and dismount the steering gear box from the chassis.
·
Clean the external portion of the steering
box,
·
Remove the side cover from the steering
gear box,
·
Remove the cross shaft from the steering gear
box casing,
·
Loosen the steering column bolts and
remove it out.
3. Describe the procedure for servicing of the
manual steering system.
Same as
question no 2
4. Describe the procedure for servicing of rack
and pinion type of steering.
·
Slide
driver seat as back as possible.
·
Put off
the front part of floor mat on the driver side and remove steering shaft joint
cover.
·
Remove the
steering shaft lower joint bolt and disconnect lower joint bolt form pinion.
·
Hoist car
at appropriate height and remove both wheels.
·
Remove
quarter pin/split pins and tie rod castle nuts from both knuckles.
·
Disconnect
both tie rod ends from knuckle using special tool.
·
Remove
steering gear cage mount bolts gear cage brackets and then gear case.
·
Remove the
rubber boot wire clip and remove the rubber boot from the tie rod.
·
Unbend
parts of tie rod lock washer and remove tie rod from rack.
·
Remove the
rack damper screw cap, damper screw and remove the plunger from steering rack.
5. State types of powers used in operation of
power steering.
·
Hydraulic
operated power steering:
·
Electronic power
assisted steering system EPS
6. Describe the procedure for inspection of
power steering.
·
Park the
vehicle on the level ground
·
Switch off
the engine and check the oil level in power steering container
·
It should be between minimum and maximum level
·
Type of
fluid is known as power steering fluid
·
Check
power steering hose connections for leakage/damages/cracks
·
Check and
replace fluid filter at regular interval as per service manual.
·
Inspect
the functioning of centrifugal pump in turning of vehicle, if faulty replace
the pump
·
Carry out
bleeding operation after each service
7. Describe principle of working of air
suspension system.
Air suspension is a type of vehicle suspension powered by
an electric or engine driven air pump or compressor. This pump compresses the
air using compressor. Compressed air is sent to the balloon. Air suspension is
used in place of conventional steel springs and in heavy vehicle applications
such as buses and trucks. If the engine is left off for an extended period, the
vehicle will gradually settle to the ground. The purpose of air suspension is
to provide a smooth, constant ride quality and in some cases it is self-leveling.
Now days gas filled shock absorber are being used for more comfort.
8. What is function of steering in vehicle?
The function of steering system is
to turn the vehicle either left or right.
9. Write the name of components of steering
system.
·
Steering wheel
·
Steering Column
·
Rack and pinion
·
Steering knuckle
·
Steering gear
·
Tie Rods
10.
In modern
vehicle which types of steering are used?
Power steering system
11.
What are
limitations of manual steering?
·
It is bigger in size.
·
At low speed, need to put in a lot of
effort to turn the wheel.
·
It is difficult to handle in city traffic
conditions.
12.
What are
advantages of power steering over manual steering?
·
Easy of operations (easy to turn)
·
With less effort on the steering.
·
Smoother than simple steering.
·
More comfortable to driver
SESSION 6: STEERING SYSTEM ADJUSTMENTS
I. FILL IN
THE BLANKS
1.
Wheels which are out of balance generally produce a vibrationthat
makes uncomfortable
to drive a vehicle.
2.
The first sign that wheels may be out of balance is
when steering wheel starts to wobble at certain speed.
3.
Wheel alignment consists of adjusting the angle
of the wheels so that they are set to the manufacturer's specification.
4.
When the wheels tilt out ward at top the camber is positive.
5.
Toe-in is a measurement of how much the front and/or
rear wheels are turned in or outfrom
a straight-ahead position.
6.
Toe in adjustment maintains the normal wearof
the tyre.
7.
Defined as the angle, created by the steering pivot
point from the front to back of the vehicle is called caster angle.
8.
The distance between the center of the front axle and
the rear axle is called the wheel -base.
9.
The improper wheel base causes abnormal tyre wear.
10.
When the vehicle is steered the inner wheel turns an
angle of 23
degrees the outer wheel turns an angle of 20 degrees.
II. ANSWER THE FOLLOWING:
1.
Make a list
of preliminary procedure for wheel alignment
·
Check all
tyres for the proper inflation pressure and also same tread wear
·
Check for
the run out of the tyre and wheel
·
Check for
the looseness of the ball joint
·
Check and
adjust the slackness of the suspension system
·
Check for
the loose of suspension arm
·
Check for
loose or missing stabilizer bar attachment
·
Test for
the binding in the steering gear
·
Lubricate
the ball joints and tighten the joints with specified torque
·
Tighten the U Clamp Bolts at regular
intervals.
2.
Make a list
of adjustments which can be done in steering gear
Ø
Worm shaft and play adjustments
·
Hold the
steering wheel by the right hand and with a left hand hold the steering column
·
Now pull
and push the steering shaft /worm shaft in and out
·
If
excessive play is noticed check the condition of the worm shaft bearings or add
the shims again check the end play.
Ø
Cross shaft end play adjustments
·
Loosen the
adjusting nut of the cross shaft
·
Now pull
and push the cross shaft in and out
·
If
excessive play is noticed then tighten the stud and reduce the play
·
After
setting the play tighten the nut
3.
What is the use of castor plate?
Caster is the forward and backward
adjustment in the plates. The purpose of caster is to keep the tires as
vertical as possible through a turn, to better grip and tractions.
4.
Write the turning radius of two
small cars?
The turning radius of two small cars as 35.5 feet (10.82m). It is often
used as a generalized term rather than a numerical figure
5.
What is a Wheel Balancing/Wheel
alignment?
Wheel balancing is the process of
balancing the weight of a tire and wheel assembly so that it travels evenly at
high speeds.
6.
Why wheel balancing is required in a
vehicle?
To eliminate vibration and avoid premature
wear caused by an imbalance in the rotating wheel and tyre assembly.
7.
How dynamic balancing of wheel is
carried out with the help of balancing machine?
Wheels are balanced on a wheel
balancing machine. The machine rotates the wheel assembly and automatically
calculates the weight and location of the balance counter, As a result of wheel
balancing, one will feel a smoother ride and low wear from tyres.
8.
Write the symptoms of imbalanced
wheel in the vehicle?
·
Faster thread wear
·
Poor fuel economy
·
Tires are uneven
·
Vibration in the steering wheel
9.
What are the ill-effects, if wheels
are not properly balanced in a car?
·
Faster thread wear
·
Poor fuel economy
·
Tires are uneven
·
Vibration in the steering wheel
10. What do you understand by toe-in and toe-out?
Toe – in: Toe-in is
a measurement of how much the front and/or rear wheels are turned in or out
from a straight-ahead
position. When the wheels are turned in, toe is positive (+). When the wheels
are turned out, toe is negative (-).
Toe – out: Is a the
difference in angles between the front two wheels during a turn, steering
system is designed to turn the inner wheel at more angle then the outer wheel.
11. What is castor angle and how does it affects steering system?
·
Defined as
the angle, created by the steering pivot point from the front to back of the
vehicle. Caster is positive if the line is angled forward, and negative if
backward.
·
Caster is
affected by the vehicle height, therefore it is important to keep the body at
its designed height.
12.
What is
camber angle and how does it affects steering system?
Ø
Camber is
the tilting of the front wheels from the vertical
·
When the
wheels tilt out ward at top the camber is positive
·
When the
wheels tilt inward ward at the top, the camber is negative
·
Camber
maintains the directional stability
Ø
The change
in the camber causes due to damaged, loose, bend, dented or worn out suspension
parts and they should be replace.
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