Basics Of Automobile

AUTOMOTIVE TECHNOLOGY

(BASICS)

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ANATOMY OF AN AUTOMOBILE
(REAR WHEEL DRIVE - 2WD)
STEERING
TYRE TYRE
BRAKE BRAKE

WHEE TRACK
EL
ENGINE GEAR BOX
DIFFERENTIAL

K
PROPELLOR
CLUTCH SHAFT - REAR

BRAKE
SUSPENSION BRAKE
TYRE TYRE

WHEEL BASE

(FOUR WHEEL DRIVE)
STEERING
TYRE PROPELLOR TYRE
BRAKE SHAFT - FRONT BRAKE

TRANSFER
CASE - 4WD

WHEE TRACK
DIFFERENTIAL
4WD

EL
ENGINE GEAR BOX
DIFFERENTIAL

K
PROPELLOR
CLUTCH SHAFT - REAR

BRAKE
SUSPENSION BRAKE
TYRE TYRE

WHEEL BASE

(FRONT WHEEL DRIVE)
STEERING
TYRE TYRE
BRAKE BRAKE

WHEE TRACK
TRANSAXLE
FTS

EL
RIVE SHAF

CLUTCH
NGINE
DR

EN

K
BRAKE
SUSPENSION BRAKE
TYRE TYRE

WHEEL BASE

SYSTEMS IN AN AUTOMOBILE
A. POWER TRAIN SYSTEM

• POWER PLANT (POWER GENERATION - ENGINE)

• ENGINE
• FUEL SYSTEM
• INTAKE SYSTEM
• EXHAUST SYSTEM
• COOLING SYSTEM

• DRIVE LINE (POWER TRANSMISSION )

• CLUTCH
• GEAR BOX/TRANSMISSION
• TRANSFER CASE
• DIFFERENTIAL
• WHEELS/TYRES

B. RUNNING SYSTEM

• SUSPENSION
• STEERING
• BRAKING

C.
C COMFORT SYSTEM

• HVAC/AC/HEATER SYSTEM
• SEATING/UPHOLSTRY/FACIA/INSTRUMENTS
• AUDIO/VIDEO/GPS

ANATOMY OF AN AUTOMOBILE - POWER PLANT

STEERING
TYRE PROPELLOR TYRE
BRAKE SHAFT - FRONT BRAKE

TRANSFER
CASE - 4WD

WHEE TRACK
DIFFERENTIAL
4WD

EL
ENGINE GEAR BOX
DIFFERENTIAL

K
PROPELLOR
CLUTCH SHAFT - REAR

BRAKE
SUSPENSION BRAKE
TYRE TYRE

WHEEL BASE

ENGINE

ENGINE IS THE HEART OF THE AUTOMOBILE

• IT GENERATES MOTIVE POWER FOR LOCOMOTION

• IT CONVERTS CHEMICAL ENERGY OF THE FUEL TO
MECHANICAL ENERGY

• ENGINE DEVELOPS POWER & TORQUE

TORQUE : - Is the capacity to do work
Measured in Kg-m , N-m , Lb-ft

POWER : - How fast the work can be done
Measured in - Horse Power, Kilo watt

CLASSIFICATION OF ENGINES
ENGINES CAN BE CLASSIFIED IN MANY WAYS :

1. By Mechanical construction - 4 Stroke/2-Stroke
Stroke/2 Stroke

2. By type of Ignition - Compression Ignition/Spark Ignition

COMPRESSION IGNITION ENGINES

• Basically Diesel engines
• Use diesel fuel
• Combustion is initiated by heat, on its own

SPARK IGNITION ENGINES

• Basically Petrol engines, LPG engines, CNG engines
• Use leaded or unleaded petrol Alcohol LPG or CNG
petrol, Alcohol,
• Combustion is initiated by a spark from a spark plug

DIESEL ENGINE
DIESEL ENGIENS ARE COMPRESSION IGNITION ENGINES & USE DIESEL FUEL

DIESEL ENGINES ARE BROADLY CLASSIFIED AS DIRECT INJECTION (DI) AND
INDIRECT INJECTION (IDI)

DIRECT INJECTION ENGINE (DI)

ON DIRECT INJECTION DIESEL ENGINES, FUEL IS SPRAYED DIRECTLY ON TOP OF
THE PISTON.

• Highly fuel efficient
• Noisy
• Easy cold starting ability

INDIRECT INJECTION ENGINE

ON INDIRECT INJECTION DIESEL ENGINES, FUEL IS SPRAYED ON TO A SEPERATE
PRE-CHAMBER.

• Less fuel efficient
• Less Noisy/smoother
• Requires pre-heating for starting

PETROL/CNG/LPG ENGINES
PETROL ENGINES ARE SPARK IGNITION ENGINES & USE GASOLINE/CNG/LPG FUEL

PETROL ENGINES ARE BROADLY CLASSIFIED AS CARBURATED AND FUEL INJECTED
ENGINE

CARBURETED ENGINE

ON CARBURETED ENGINE , THE PETROL & AIR ARE MIXED IN THE CARBURETER
BEFORE BEING SENT IN TO THE ENGINE

FUEL INJECTED ENGINE

ON FUEL INJECTED ENGINES, THE PETROL IS INJECTED SEPERATELY AND THE
PETROL AND AIR ARE MIXED INSIDE THE CYLINDER.

FUEL INJECTED ENGINES CAN BE FURTHER CLASSIFIED AS :

SINGLE/MULTI POINT FUEL INJECTION, Where the fuel is injected outside the cylinder

GASOLINE DIRECT INJECTION (GDI) , Where the fuel is injected directly in to the engine
cylinder

INTERNAL COMBUSTION ENGINE

RECIPROCATING ROTARY GAS TURBINE

4STROKE 2STROKE

COMPRESSION IGNITION SPARK IGNITION
(DIESEL) (GASOLINE/LPG/CNG)

CARBURETED
INDIRECT INJECTION

INJECTED

DIRECT INJECTION

SINGLE POINT MULTI POINT DIRECT
INJECTION INJECTION INJECTION

THERMAL EFFICIENCY

C
O
O EFFICIENCY = OUTPUT
L 33% % INPUT
I
N
G

INPUT OUTPUT

FUEL ENGINE WORK

33%
100%

E TYPICAL EFFICIENCIES
X
H 33%
A PETROL - 25%
U
S
DIESEL IDI - 28-30%
T DIESEL DI - 32-33%

FUEL EFFICIENCY
(FUEL CONSUMPTION)

FUEL EFFICIENCY IS A COMBINATION OF ENGINE EFFICIENCY,
VEHICLE PARAMTERS & DRIVING PATTERN

ENGINE EFFICIENCY
+
TRANSMISSION EFFICIENCY
(CLUTCH+GEARBOX+DIFFERENTIAL+ WHEELS + TYRES)
+
WEIGHT/LOAD/SPEED
+
AERODYNAMIC PARAMETERS
(DRAG - BODY SHAPE)
+
DRIVING PATTERN
(DRIVING STYLE & TRAFFIC CONDITIONS)

FUEL EFFICIENCY - Kms/Lit OR Lit/100 Kms

ENGINE PARAMETERS
CLEARANCE VOLUME

STROKE, mm

BORE,mm

CYLINDER CAPACITY,cc

ENGINE CAPACITY, cc = CYL. CAPACITY X No OF CYL
UNITS - cc - Cubic centimeter
- Lit - Liters = cc/1000

ENGINE PARAMETERS
BORE,
BORE mm : Th diameter of the cylinder
The di t f th li d

STROKE, mm : The distance between top most point of piston travel to the
bottommost point of piston movement
p p

CAPACITY, cc : Also called displacement. The volume displaced by all
pistons while moving from top to bottom. Also indicated in Liters.

CLEARANCE VOLUME : The volume available above piston, with the
piston in top most point.

COMPRESSION RATIO : The ratio between the total volume to the
clearance volume.

VALVE MECHANISM : The mechanism by which the valves are
operated. It could be push rod type or overhead camshaft type

TIMING SYSTEM : The mechanism by which the camshaft & fuel
injection pump are operated . It could be gear driven, chain driven or
belt driven.

VALVE LAYOUTS
(NO. OF VALVES PER CYLINDER)

I
E I
E

2 VALVES/CYL 2 VALVES/CYL

E
E E
I I
I I

3 VALVES/CYL 4 VALVES/CYL

VALVE OPERATING MECHANISM
ROCKER SHAFT
(CAMSHAFT LOCATIONS)
ROCKER ARM
CAMSHAFT
ROCKER ARM ROCKER SHAFT

VALVE
HYDRAULIC
TAPPET

PUSHROD CYL HEAD CYL HEAD CYL HEAD

TAPPET FUEL PUMP

CAMSHAFT CYL CYL CYL
BLOCK BLOCK BLOCK

CRANKSHAFT

SOHC DOHC

PUSH ROD ENGINE OVERHEAD CAM ENGINE

SINGLE OVERHEAD CAMSHAFT (SOHC)

E I E I E I E I

2 VALVES/CYL , SOHC - VALVES OPERATED EITHER DIRECTLY OR THROUGH
ROCKERS

E E E E E E E E

I I I I I I I I

4 VALVES/CYL , SOHC - VALVES OPERATED THROUGH ROCKERS

DOUBLE OVERHEAD CAMSHAFT (DOHC)

E E E E E E E E

I I I I I I I I

4 VALVES/CYL , DOHC - VALVES OPERATED EITHER DIRECTLY OR THROUGH
ROCKERS

TIMING MECHANISM
GEAR DRIVE ENGINE GEAR DRIVE ENGINE

CYL HEAD CYL HEAD

CAMSHAFT FUEL PUMP

IDLER

CRANKSHAFT

CYL HEAD

CYL HEAD

CHAIN DRIVE ENGINE
BELT DRIVE ENGINE

ENGINE SUPPORT SYSTEMS

FOR THE ENGINE TO FUNCTION, IT REQUIRES SUPPORT SYSTEMS.
FUNCTION SYSTEMS
THE MAJOR SUPPORT SYSTEMS OF AN ENGINE ARE :

FUEL SYSTEM

INTAKE SYSTEM

EXHAUST SYSTEM

COOLING SYSTEM

FUEL SYSTEM
• FUEL SYSTEM IS THE HEART OF THE ENGINE

• IT TRANSPORTS FUEL FROM THE FUEL TANK AND INJECTS IT UNDER
HIGH PRESSURE IN TO THE ENGINE

• FUEL INJECTION SYSTEM IS A HIGH PRECISION, HIGH TECHNOLOGY
PRODUCT

• FUEL INJECTION PUMPS ARE OF 2 TYPES - INLINE PUMP & ROTARY
PUMP

• COMPONENTS OF FUEL SYSTEM ARE :
• FUEL INJECTION PUMP(FIP)
• FUEL TRANSFER PUMP
• FUEL INJECTORS
• FUEL FILTERS
• FUEL LINES

FUEL SYSTEM
INJECTOR
INLINE PUMP

ENGINE
OVERFLOW
FIP FUEL TANK

SUPPLY
TRANSFER PUMP

PRIMER
ROTARY PUMP

FUEL FILTER

ENGINE

FIP
FUEL TANK

FUEL SYSTEM COMPONENTS
1. FUEL INJECTION PUMP - Fuel injection pump sucks fuel from the
tank , pressurises the fuel to approx. 600 - 1000 bar and sends it to
the i j t
th injectors.

• Inline FIP - Has separate pumping chambers for each cylinder

• Rotary FIP(Distributor pump) - Has one pumping chamber and the
pump distributes to each cylinder as per sequence- firing order

2. INJECTORS - Inject the high pressure fuel in to each cylinder.

3. FUEL FILTER - Filters the fuel from dirt & sediments, since the Fuel
,
injection pump requires clean fuel.

INTAKE SYSTEM
INTAKE SYSTEM CLEANS & TRANSPORTS ATMOSPHERIC AIR
TO THE ENGINE CYLINDERS

NA ENGINE - NATURALLY ASPIRATED ENGINE - The air is
transported to the engine cylinder , at atmospheric pressure

TURBO ENGINE - TURBO CHARGED ENGINE - The air is
compressed and transported to engine cylinder, at higher than
atmospheric pressure.
p p

COMPONENTS OF THE INTAKE SYSTEM

• AIR FILTER
• TURBO CHARGER
• INTERCOOLER
• AIR FILTER CLOGGING INDICATOR
• HOSES

INTAKE SYSTEM CLOGGING INDICATOR

AIR FILTER

ENGINE

EXHAUST

NATURALLY ASPIRATED ENGINE

INTAKE SYSTEM CLOGGING INDICATOR

AIR AT ATMOSPHERIC
AIR FILTER
PRESSURE

HOT COMPRESSED AIR

COOL COMPRESSED AIR

INTERCOOLER
ENGINE
TURBOCHARGER

EXHAUST

TURBO CHARGED/INTERCOOLED ENGINE

INTAKE SYSTEM

1. AIR FILTER - The purpose of the air filter is to clean the atmospheric air
of dirt & dust before entering the engine cylinder. Air filters needs to
cleaned regularly and replaced at recommended intervals.
l d l l d l d t d di t l

2. CLOGGING INDICATOR - Clogging indicator indicates the condition of
t e air te
the a filter as to whether is c ea o c o ed
et e s clean or choked.

A visible RED band in the indicator indicates choked air filter

INTAKE SYSTEM

3. TURBOCHARGER - The turbo charger utilizes the wasted heat energy
in the exhaust system, to run a compressor which compresses the intake
air. Compressed intake air has more density and hence more fuel can be
injected i
i j t d increasing the power of the engine.
i th f th i

Turbo charging is an ideal way to increase the engine power without
increasing the engine size.
g g

For trouble free performance of turbocharger a clean air filter element is a
must.

A turbo charger spins at very high speed (~ 1.6 Lakh RPM). The turbo
charger is lubricated by engine oil. If the engine is switched off abruptly ,
the oil supply to turbo bearing stops instantly. Since the turbine is
running at very high speeds, it takes some time to wind down. During this
time the turbine bearing can be starved off oil.

Hence it is recommended to idle the engine for some time before shutting
off the engine.

INTAKE SYSTEM

4. INTERCOOLER - When the atmospheric air is compressed by the
compressor in the turbocharger, the temperature of the air increases. The
temperature of the air needs to be reduced before it enters the engine
cylinder. The hot compressed air is passed through a i t
li d Th h t d i i d th h intercooler t
l to
reduce the temperature.

Intercooler is a heat exchanger where the hot compressed air flows on
g p
the inside and cool atmospheric air flows on the outside leading to
cooling of the compressed air

ATM
AIR

HOT COMPRESSED AIR INTERCOOLER COOL COMPRESSED AIR

EXHAUST SYSTEM
EXHAUST SYSTEM TRANSPORTS THE BURNED EXHAUST
GASES FROM ENGINE CYLINDER TO THE ATMOSPHERE,
TOWARDS THE REAR OR TO THE RIGHT SIDE OF THE VEHICLE.

Since the exhaust gases are at higher pressure than atmospheric
pressure, the exhaust system has to reduce the pressure of
exhaust gases so that there is no noise on discharge to
h t th t th i i di h t
atmosphere.

Catalytic converter (if fitted) reduces harmful pollutants in the
exhaust gases to un-harmful gases.

COMPONENTS OF EXHAUST SYSTEM

• SILENCER/MUFFLER/EXPANSION CHAMBER
• CATALYTIC CONVERTER
• OXYGEN SENSOR (PETROL VEHICLES)

EXHAUST SYSTEM
AIR FILTER
CLOGGING INDICATOR DOWNSTREAM
OXYGEN
SENSOR
INTERCOOLER
(PETROL)
TURBOCHARGER

ENGINE CATALYTIC
UPSTREAM CONVERTER
OXYGEN
SENSOR
EXHAUST (PETROL)
SILENCER
MUFFLER

TO ATMOSPHERE

EXHAUST SYSTEM
1. SILENCER/MUFFLER/EXPANSION CHAMBER - Silencers are separate
chambers fitted on the exhaust system fitted with baffles on the inside. The
silencer reduces the pressure of the exhaust gases progressively and lets
out th exhaust gases to atmosphere at atmospheric pressures.
t the h t t t h t t h i

2. CATALYTIC CONVERTER - Catalytic converters are emission control
devices fitted on the exhaust system. Catalytic converters convert harmful
y y
exhaust gases to un-harmful gases. Catalytic converters are coated with
noble metals like Platinum, Palladium, Rhodium on the inside.

Catalytic converters are of 2 types namely :
types,

A. OXIDATION CATALYST - Fitted on diesel engines. Converts CO, HC to CO2
and H20.

B. THREE WAY CATALYST - Fitted on Petrol engines. Converts CO, HC &
NOx to CO2 , H20 & N2.

COOLING SYSTEM
COOLING SYSTEM REMOVES THE EXCESSIVE HEAT OF
COMBUSTION FROM THE ENGINE.

Cooling system circulates coolant (Combination of water and a
chemical) through the engine components which absorbs the heat
and transfers the heat to the atmospheric air through a heat
exchanger.

COMPONENTS OF THE COOLING SYSTEM

• WATER PUMP
• THERMOSTAT
• COOLING FAN
• OIL COOLER
• RADIATOR
• RADIATOR PRESSURE CAP
• COOLANT RECOVERY TANK/DEGASSING TANK
• DRIVE BELTS

RADIATOR PRESSURE CAP
COOLING SYSTEM

THERMOSTAT

AIR ENGINE

RADIATOR

WATER PUMP
COOLING OIL COOLER
FAN

BASIC SYSTEM

COOLANT
COOLING SYSTEM
RECOVERY RADIATOR PRESSURE CAP
TANK

THERMOSTAT

AIR ENGINE

COOLING
FAN

WATER PUMP
OIL COOLER
RADIATOR

COOLANT RECOVERY SYSTEM
(No Loss System)

DEGASSING
TANK COOLING SYSTEM
PRESSURE CAP
COOLING
FAN

THERMOSTAT

MAX

ENGINE
AIR

OIL COOLER
WATER PUMP
RADIATOR

GASES
DEGASSING TANK SYSTEM
(No Loss System & Degassing)

COOLING SYSTEM
1. WATER PUMP - Water pump sucks water from the radiator bottom tank
and pushes the water in to the engine block/cylinder head. Water pump is
driven by the engine crankshaft by a belt (in some cases it may be gear
driven)

2. THERMOSTAT - Thermostat is a temperature sensitive valve fitted on the
outlet of the engine. The thermostat will open only when the predetermined
temperature (75-90 C) is reached. Thermostat ensures that a cold engine
warms up f t and also ensures engine runs at optimum temperature for
faster d l i t ti t t f
best fuel efficiency.

2.RADIATOR - Radiator is a heat exchanger. The hot coolant (water) from
g ( )
engine enters to the top tank of the radiator and passes through the core to
the bottom tank of the radiator. Cool atmospheric air is drawn over the core
by the cooling fan, leading to cooling of the radiator water. Radiators can be
of :

Down Flow type - Water passes from top tank to bottom tank in a downward
direction.
Cross Flow type - Water passes from left to right across the radiator.

Radiators can be made of Copper or Aluminum

COOLING SYSTEM
4. RADIATOR PRESSURE CAP - Water normally starts boiling at 100 deg C.
In order to increase the boiling temperature of water, the cooling system is
pressurized. The Radiator pressure cap is set at 0.9 Bar so that the cooling
system operates under a pressure of 1.9 Bar. When the pressure exceeds
1.9 Bar, the pressure valve opens and lets out the excessive pressure along
with some coolant. When the engine cools down , the vacuum valve opens
and let in air so that the radiator does not collapse inwards due to vacuum.

5.
5 COOLING FAN - C li
Cooling fan sucks i fresh cool air through the radiator,
f k in f h l i th h th di t
thus cooling the hot water. Cooling fan can be of 3 types based on how it is
driven & controlled.

MECHANICAL FAN - Is driven by the engine crankshaft by a belt. Cooling fan speed is
dependent on engine speed.

VISCOUS FAN - Is driven by the engine by a belt. However, the speed of the fan is
y g y , p
controlled by a viscous clutch based on the radiator temperature.

ELECTRIC FAN - Is driven by an electric motor. The motor is controlled by a
controller based on various parameters like engine temperature, engine speed, A/c
p g p , g p ,
operation etc.

COOLING SYSTEM
6. OIL COOLER - Oil cooler is a heat exchanger which uses coolant to cool
the engine oil. The hot engine oil is passed through the inside of the oil
cooler and a relatively cool coolant flows on the outside.

ENGINE
COOLANT

HOT ENGINE OIL OIL COOLER COOLER ENGINE OIL

ANATOMY OF AN AUTOMOBILE - DRIVELINE

STEERING
TYRE TYRE
BRAKE BRAKE

TRANSFER
CASE - 4WD

WHEE TRACK
DIFFERENTIAL
4WD

EL
ENGINE GEAR BOX
DIFFERENTIAL

K
PROPELLOR
CLUTCH SHAFT

BRAKE
SUSPENSION BRAKE
TYRE TYRE

WHEEL BASE

DRIVELINE - POWER TRANSMISSION
POWER IS GENERATED BY THE POWER PLANT (ENGINE)

THE GENERATED POWER NEEDS TO BE MODIFIED &
TRANSMITTED TO THE WHEELS FOR VEHICLE LOCOMOTION.

DRIVELINE MODIFIES & TRANSMITS THE POWER/TORQUE TO
THE WHEELS OF THE AUTOMOBILE.

COMPONENTS OF DRIVELINE

• CLUTCH
• PROPELLOR SHAFT
• DIFFERENTIAL
• AXLE SHAFTS
• WHEELS
• TYRES

CLUTCH SYSTEM
CLUTCH IS THE CRUCIAL LINK BETWEEN THE POWER PLANT
(ENGINE) AND THE DRIVELINE

THE PURPOSE OF THE CLUTCH IS TO LINK OR DE
DE-
LINK(ENGAGE OR DIS-ENGAGE) THE ENGINE FROM THE
DRIVELINE, AS DESIRED BY THE DRIVER

COMPONENTS OF CLUCH

• CLUTCH ACTUATION MECHANISM
• LINK TYPE
• CABLE TYPE
• HYDRAULIC TYPE
• CLUTCH CABLE
• CLUTCH MASTER CYLINDER
• CLUTCH SLAVE CYLINDER
• RELEASER BEARING
• CLUTCH PRESSURE PLATE
• CLUTCH DRIVEN PLATE

CLUTCH SYSTEM
ENGAGED CLUTCH PEDAL -FREE

LINKED DIS-ENGAGED

CLUTCH PEDAL -PRESSED
ENGINE GEAR BOX

CLUTCH

DE LINKED
DE-LINKED

CLUTCH ACTUATION ENGINE GEAR BOX
MECHANISM

CLUTCH ACTUATION MECHANISM
The clutch operating mechanism transfers the force exerted by the
driver at the clutch pedal to the clutch and either engages or
disengages the clutch.

Clutch actuation mechanism can be classified as :

1.
1 Mechanical Clutch - Where the driver s foot effort is transmitted
driver’s
to the clutch through a set of levers and links

2. Cable Clutch - Where the driver s foot effort is transmitted to the
driver’s
clutch through a cable.

3. Hydraulic Clutch - Where the driver’s foot effort is transferred to
y
a hydraulic oil medium, which in turn operates the clutch through
master cylinder & slave cylinder. Pedal efforts are lower & doesnot
require clutch pedal free play adjustments.

ENGAGED RESERVOIR HYDRAULIC CLUTCH SYSTEM
CLUTCH PEDAL -FREE

MASTER CYLINDER
LINKED CLUTCH DIS-ENGAGED

CLUTCH PEDAL -PRESSED
ENGINE GEAR BOX
RESERVOIR

SLAVE CYLINDER

DE-LINKED

CLUTCH PIPES/TUBES

ENGINE GEAR BOX

HYDRAULIC CLUTCH SYSTEM

1. CLUTCH MASTER CYLINDER - Converts driver’s foot effort to
hydraulic pressure and transmits the pressure to clutch slave
cylinder

2. CLUTCH SLAVE CYLINDER - Receives the hydraulic pressure
from Clutch master cylinder and moves the clutch fork to either
f Cl t h t li d d th l t h f k t ith
disengage or engage the clutch mechanism

3.
3 CLUTCH PIPES/TUBES - The connection between the Clutch
master cylinder and Clutch slave cylinder, transmitting the
hydraulic fluid.

4. RESERVOIR - The storage for clutch fluid

CLUTCH MECHANISM
FLYWHEEL
CLUTCH DRIVEN PLATE
CLUTCH PRESSURE PLATE

ENGINE GEAR BOX

RELEASER BEARING

ENGAGE

CLUTCH FORK

CLUTCH PEDAL FREE
CLUTCH ENGAGED

CLUTCH MECHANISM
FLYWHEEL
CLUTCH DRIVEN PLATE
CLUTCH PRESSURE PLATE

ENGINE GEAR BOX

RELEASER BEARING

DIS-ENGAGE
DIS ENGAGE

CLUTCH FORK

CLUTCH PEDAL PRESSED
CLUTCH DISENGAGED

CLUTCH MECHANISM
1.
1 CLUTCH DRIVEN PLATE - Cl t h pressure plate is the link
Clutch l t i th li k
between the engine & gear box transmitting power & torque to the
driveline. In engaged condition, the clutch plate is sandwiched
between the engine flywheel & the Clutch pressure plate
plate.

2. CLUTCH PRESSURE PLATE - Clutch pressure plate ensures that
the clutch plate is clamped tightly to the flywheel in engaged
condition and releases the clutch plate from flywheel in dis-
engaged condition. The drivers’ foot effort is transmitted to the
clutch pressure plate through the actuation mechanism and the
p p g
releaser bearing.

3. RELEASER BEARING

4. CLUTCH FORK

GEAR BOX
(TRANSMISSION)

GEAR BOX MODIFIES & TRANSMITS THE TORQUE OF THE ENGINE
TO THE DRIVE LINE.

THE AMOUNT OF MODIFICATION OF TORQUE REQUIRED IS
DECIDED BY THE DRIVER AND IS ACTUATED BY A GEAR LEVER
WHICH SELECTS A REQUIRED GEAR RATIO.

COMPONENTS OF GEAR BOX

• GEAR BOX
• GEAR SELECTION LEVER

GEAR BOX
(TRANSMISSION)
GEAR BOXES ARE CLASSIFIED AS :

• STEPPED TRANSMISSION
• STEPLESS TRANSMISSION (USED MOSTLY IN 2 WHEELERS)

STEPPED TRANSMISSION ARE GEAR BOXES WHICH HAS
DEFINED STEPS OR GEAR RATIOS. THE NUMBER OF STEPS CAN
RATIOS
BE 3 , 4 OR 5.

STEPPED TRANSMISSIONS CAN BE FURTHER CLASSIFIED AS

MANUAL TRANSMISSION WHERE THE REQUIRED STEP OR GEAR
IS SELECTED BY THE DRIVER, AS PER THE DRIVING
,
REQUIREMENT

AUTOMATIC TRANSMISSION WHERE THE STEP OR GEAR RATIO
IS AUTOMATICALLY SELECTED, AS DECIDED BY A ECU BASED
ON INFORMATION FROM VARIOUS SENSORS

GEAR LEVER
GEAR BOX
(MANUAL TRANSMISSION)
SHIFT RAILS

MAIN SHAFT

FOURTH GEAR
SYNCHRONISER
FROM CLUTCH

TO PROP SHAFT

SECON GEAR

FIRS GEAR
THIRD GEAR

FIFTH GEAR
COUNTER SHAFT ST
ND

H
D

REVERSE GEAR NOT SHOWN

GEAR BOX
GEAR RATIO - G Gear ratios are gear reduction steps in the gear
ti d ti t i th
box. A gear reduction multiplies the engine torque by the gear
ratio amount. Torque requirement at the wheel depends
operating conditions For example :
conditions.

To move a vehicle from standstill requires much more torque than
the peak torque of the engine. Hence the torque is multiplied by
the first gear ratio.

Once the vehicle is started and moved using first gear, it requires
g g q
less torque at the wheels to keep it moving. Hence it requires no
multiplication or very less multiplication.

If the vehicle suddenly encounters a gradient , it will require more
torque at the wheels to keep the vehicle moving. Hence a
intermediate ratio is required.

GEAR BOX
GEAR CHANGE MECHANISM(EXTERNAL) - A desired gear ratio
can be selected by the driver by selecting and shifting the gear
lever
GEAR SHIFTING

1 3 5 1 3
GEAR SELECTION

2 4 R 2 4 R

5 SPEED TRANSMISSION 4 SPEED TRANSMISSION
S S SS O
• BA10 • KMT 90
• NISSAN • MS 90
• ISUZU

GEAR BOX
GEAR CHANGE MECHANISM(INTERNAL) - The desired gear ratio
selected by the driver is transmitted through the gear lever, set of
shift rails to the gears located inside the gear box.

The
Th gear shifting mechanism i id th gear box can be broadly
hifti h i inside the b b b dl
classified as :

SLIDING MESH - In which , the gears needs to be moved physically in
to mesh with the corresponding gear. This requires that the vehicle is
stationary when the gears are shifted, Hence sliding mesh is obsolete
and is used only in First Gear or Reverse gear.

CONSTANT MESH - In which, all the gears are in constant mesh and
the required gear engagement is achieved by operating a
q g g g y p g
synchroniser mechanism. Synchronisation mechanism can be
classified as :

Manual Synchronisation - Double de-clutching
Automatic Synchronisation - Single stroke shifting

GEAR BOX
SYNCHRONISER MECHANISM - In order to avoid gears crashing,crashing
when shifting from one gear ratio to another, it is required to match
the speeds of both the drive & the driven gears, before the shifting
can happen.

Synchroniser mechanism does the job of synchronising the speeds
of the drive & driven gear so that shifting takes place smoothly.

All forward gears (except First) need to have synchronisers

Synchroniser mechanism are of different designs :

Strut type

Pin Type

TRANSFER CASE

TRANSFER CASES ARE FITTED ONLY IN 4WD VEHICLES

TRANSFER CASE MODIFIES & RE-DIRECTS THE TORQUE OF THE
ENGINE TO BOTH FRONT AND REAR AXLES, AS DESIRED.

4WD VEHICLES CAN BE CLASSIFIED AS :

FULL TIME 4WD - Where all the 4 wheels are connected to the
engine, permanently
engine permanently. Also known as All Wheel Drive(AWD)

PART TIME 4WD - Where either 2WD mode or 4WD mode can be
selected by the driver by shifting a gear lever (Manual shift)) or by
turning a switch (Electric shift)

TRANSFER CASE
Sliding/Meshing gear type
g/ gg yp

FROM GEAR BOX

LOW GEAR HIGH GEAR

2WD/4WD COUPLING

TO REAR
TO FRONT
2WD HIGH

4WD LOW
2WD MODE
N 4WD HIGH

TRANSFER CASE
Sliding/Meshing gear type
g gg yp
FROM GEAR BOX FROM GEAR BOX

TO REAR
TO FRONT
TO REAR TO FRONT

2WD HIGH
4WD HIGH MODE 2WD HIGH 4WD LOW MODE

O
4WD LOW
4WD LOW N 4WD HIGH
N 4WD HIGH

TRANSFER CASE
Planetary g
y gear/chain drive
RING GEAR

SUN GEAR

FROM GEAR BOX

TO REAR

PLANET GEAR
CHAIN DRIVE

2WD HIGH
TO FRONT

4WD HIGH

N

4WD LOW
2WD MODE

TRANSFER CASE
Planetary g
y gear/chain drive
RING GEAR

SUN GEAR

FROM GEAR BOX

TO REAR

PLANET GEAR
CHAIN DRIVE

2WD HIGH

4WD HIGH
TO FRONT

N

4WD LOW
4WD HIGH MODE

TRANSFER CASE
Planetary g
y gear/chain drive
RING GEAR

SUN GEAR

FROM GEAR BOX

TO REAR

PLANET GEAR
CHAIN DRIVE

2WD HIGH

4WD HIGH
TO FRONT

N

4WD LOW
4WD LOW MODE

PROPELLOR SHAFT

PROPOELLOR SHAFT TRANSMITS THE ENGINE TORQUE FROM
THE GEAR BOX/TRANSFER CASE TO THE DIFFERENTIAL.

PROPELLOR SHAFTS CAN BE EITHER :

SINGLE PROPELLOR SHAFT
SPLIT PROPELLOR SHAFT

DIFFERENTIAL

DIFFERENTIAL RECEIVES TORQUE FROM THE GEAR BOX,
MODIFIES AND TRANSMITS IT TO THE WHEELS, IN A
PERPENDICULAR DIRECTION
DIRECTION.

DIFFERENTIAL ALSO ALLOWS EACH WHEEL TO ROTATE AT
DIFFERENT SPEEDS, ESPECIALLY WHEN THE VEHICLE TAKES A
,
TURN

COMPONENTS OF DIFFERENTIAL

• CROWN WHEEL /PINION (REAR AXLE RATIO)
• DIFFERENTIAL GEARS

DIFFERENTIAL
TORQUE FROM GEAR BOX

PINION
CROWN/
RING GEAR
PLANET PINION

LEFT RIGHT

AXLE SHAFT SUN GEAR

DIFFERENTIAL CAGE

DIFFERENTIAL
1. CROWN WHEEL/PINION - Also known as rear axle ratio, is fixed
gear reduction at the rear axle. Crown wheel/pinion receives the
torque from gear box (through propeller shaft) , multiplies the
torque and directs it to both wheels in a perpendicular direction,
through the differential. Crown & Pinion pair is known as Hypoid
pair.

2. DIFFERENTIAL MECHANISM - Equalises the torque between both
wheels. Allows both wheels to rotate at different speeds to avoid
tyre slippage during cornering Due to the feature of “torque
cornering.
equalisation” , if one tyre is stuck in soft ground.mud, the other tyre
will not rotate.

3. AXLE SHAFTS - Carries the torque from the differential to the
wheels.

WHEELS
WHEELS CARRY THE LOAD OF THE VEHICLE & TRANSMIT THE
SC O O C S
TORQUE TO THE TYRES

WHEELS ARE SUPPORTED IN WHEEL BEARINGS

BASED ON WAY IN WHICH THE LOAD IS CARRIED AND THE
TORQUE IS TRANSMITTED, THE AXLE CAN BE CLASSIFIED AS :

SEMI-FLOATING AXLE - In which the vehicle load as well as the
torque are transmitted by the axle shaft

FULL FLOATING AXLE - In which the axle shaft only transmits the
drive torque to the wheels. The vehicle load is taken up by the rear
axle housing
housing.

COMPONENTS OF WHEELS

• AXLE SHAFT
• WHEEL SPINDLE
• WHEEL BEARINGS

WHEELS
AXLE HOUSING WHEEL BEARING
WHEEL
AXLE SHAFT

FROM DIFFERENTIAL

SEMI-FLOATING
SEMI FLOATING AXLE
WHEEL BEARING WHEEL

WHEEL SPINDLE
FROM DIFFERENTIAL

FULL FLOATING AXLE

WHEEL RIM
WHEEL RIMS ARE ATTACHED TO THE WHEEL AND CARRY THE
TYRE & TUBE AT THE OTHER END.

WHEEL RIMS ARE SPECIFIED AS :

1. WHEEL RIM DIAMETER - The diameter of the wheel rim is
specified in inches - 16”, 15 etc
16 , 15”

2. WHEEL RIM OFFSET - It is the difference between the wheel rim
centre and the wheel rim mounting face
g
OFFSET

DIAMETER

WHEEL RIM
WHEEL RIM SPECIFICATIONS

6J X 15

WHEEL RIM OFFSET

WHEEL RIM DIAMTER, in

TYRE
THE PURPOSE OF THE TYRE IS TO PROVIDE A FRICTIONAL
INTERFACE WITH THE ROAD SO THAT THE DRIVE TORQUE CAN
BE TRANSMITTED TO THE ROAD FOR VEHILCE MOTION.

TYRE ALSO SUPPORTS THE VEHICLE LOAD

TYRES ARE CLASSIFIED AS :

CROSS PLY TYRES - The inner plies run at an angle to the tyre
centre line

RADIAL PLY TYRE - The inner plies run perpendicular to the tyre
centre line Radial tyres have low rolling resistance and hence the
line.
fuel efficiency of the vehicle improves. Radial tyres also provide
softer ride due to the softer side walls.

TYRE
TYRE SPECIFICATIONS

ASPECT RATIO = TYRE HEIGHT X 100
------------------
TYRE WIDTH

TYRE HEIGHT

TYRE WIDTH

TYRE
TYRE SPECIFICATIONS

P 235/75 R 15
PASSENGER CAR

TYRE WIDTH , mm

ASPECT RATIO, %

RADIAL


TYRE
TYRE SPECIFICATIONS

6.00
6 00 X 16 8 PR

TYRE WIDTH , in


PLY RATING

RUNNING SYSTEM

• POWER PLANT GENERATES THE POWER/TORQUE
• DRIVELINE MODIFIES & TRANSMITS THE TORQUE

THE RUNNING SYSTEM CONTROLS THE VEHICLE

RUNNING SYSTEM CONSISTS OF

SUSPENSION - Provides a comfortable ride
BRAKES - Allows to slow down the vehicle
STEERING - Allows to change direction of the vehicle

SUSPENSION

SUSPENSION ABSORBS ROAD SHOCKS AND PROVIDES
COMFORTABLE RIDE FOR THE PASSENGERS

SUSPENSION CAN BE CLASSIFIED AS :

RIGID SUSPENSION
INDEPENDENT SUSPENSION

COMPONENTS OF SUSPENSION

• SPRINGS
• SHOCK ABSORBER
• STABILIZER BAR

SUSPENSION
1. SPRINGS - Springs are mounted at each wheel and they absorb
the road shocks created when the vehicle travels over potholes or
speed breakers.

Springs are of various types, namely :

Leaf springs - Leaf springs are multi-layered steel plates clamped
together.

Coil springs - Coil springs are made of thick steel wires wound in a
spring form

Torsion bar - Torsion bar are long steel rods of either circular or
square cross section. The springing action is generated by the
torsional forces when the torsion bar is twisted

SUSPENSION
2. SHOCK ABSORBERS - The springs absorb road shocks. While
absorbing the shock , the spring is compressed. However, due to
the characteristic of springs, the absorbed shock will be released
immediately with the rebound of the spring. Hence , the vehicle will
start oscillating after encountering a road irregularity.

The purpose of the shock absorber is to absorb the shocks when
the spring starts oscillating, thus providing a smooth ride.

Shock absorbers are of Hydraulic , double acting type or G filled
S f Gas f
REBOUND VALVE

BUMP/REBOUND
HYDRAULIC OIL BUMP VALVE

SUSPENSION
3. STABILIZER BAR - Stabilizer bars are fitted on the axles to
reduce the amount of body roll, when the vehicle is cornered.
Stabilizers bar acts as torsion bars and twist , restricting the
excessive body roll.

SUSPENSION
TYPES OF SUSPENSIONS

SUSPENSION TYPES CAN BE BROADLY CLASSIFIED AS :

RIGID SUSPENSION - In rigid suspension both the wheels in an
axle are connected by a rigid beam or a tube. Road irregularities
encountered by one wheel is partially passed on to the other wheel
t db h li ti ll d t th th h l

SPRING

AXLE
TYRE

SUSPENSION
TYPES OF SUSPENSIONS
S O SUS SO S

INDEPENDENT SUSPENSION - In independent suspension, each
wheel is mounted separately. Road irregularities encountered by
one wheel is absorbed by that wheel only.

IFS - Independent Front Suspension
IRS - I d
Independent Rear Suspension
d tR S i

STEERING
THE PURPOSE OF THE STEERING IS TO CHANGE THE
DIRECTION OF VEHICLE MOVEMENT, AS DESIRED BY THE
DRIVER.

STEERING SYSTEMS CAN BE :

MANUAL STEERING
POWER ASSISTED STEERING

COMPONENTS OF STEERING SYSTEM

• STEERING GEAR BOX
• STEERING WHEEL
• STEERING INNER/OUTER COLUMNS
• TIE RODS
• POWER STEERING PUMP
• POWER STEERING RESERVOIR
• POWER STEERING HOSES/PIPES

STEERING
MANUAL STEERING - I which, the driver’s muscular energy is
In hi h th d i ’ l i
directly used in steering the wheels of the vehicle.

POWER ASSISTED STEERING - In which the driver is aided by
which,
an external power assistance, so that the efforts required at the
steering wheel is lower.

In case of failure of the source of power, the steering system
reverts to manual steering.

Power source for the steering can be :

1. Hydraulic power - Hydraulic pressure generated by a power
steering pump, driven by the engine.

2. Electric power - An electric motor driven by the vehicle
electrical s stem and controlled b a an ECU Also kno n as
system by ECU. known
Electronic Power Steering (EPS)

STEERING GEAR BOX
STEERING
MANUAL STEERING
U S G
STEERING COLUMN
STEERING WHEEL

STEERING INTERMEDIATE COLUMN

TIE ROD
POWER ASSISTED STEERING
(HYDRAULIC)

ENGINE
POWER STEERING PUMP

STEERING GEAR BOX RESERVOIR

STEERING
1. STEERING GEAR BOX - Steering gear box converts driver’s
effort at steering wheel (Rotary) to a linear movement at tie rods.
The tie rods are connected to the wheels which turn either left or
right.

Various types of steering gear box designs are available. The
various designs are based on the type of gear reduction used
i d i b d th t f d ti d
inside the steering gear box

Worm & roller

Re-circulating Ball type (RCBT)

Rack & pinion type

Steering gear can be either Manual or Power assisted

STEERING
2. STEERING WHEEL - Transmits the driver’s hand effort to the steering
gear box.

3.
3 STEERING COLUMNS - Li k between the steering wheel and the
Link b t th t i h l d th
steering gear box.

4. TIE-RODS - The connection between the steering gear box and the
gg
wheels.

5 .POWER STEERING RESERVOIR - Holds the hydraulic steering fluid
and supplies the same to Steering pump , as and when required.
required

STEERING
6. POWER STEERING PUMP - Driven by engine. Generates hydraulic
pressure and directs it to the steering gear box.

Since the power steering pump is driven by the engine, the pump speed
Si th t i i di b th i th d
increases as the engine speed increases. Increase in the engine speed
generates more pressure of the power steering fluid. Due to higher
stee g u d p essu es, the amount of ass sta ce also c eases
steering fluid pressures, t e a ou t o assistance a so increases at
higher engine/vehicle speeds. This is not desirable as the steering
becomes softer and softer as the vehicle speed increases, leading to
difficulty in controlling the vehicle.

SPEED SENSITIVE POWER STEERING - In which a special valve
reduces the steering fluid pressure as the engine speed increases. This
is known as speed sensitive power steering.
p p g

BRAKES
THE PURPOSE OF THE BRAKES IS TO SLOW DOWN OR STOP THE
VEHICLE AS DESIRED BY THE DRIVER

BRAKE SYSTEMS CAN BE CLASSIFIED AS :

HYDRAULIC BRAKES
POWER ASSISTED BRAKES
• VACUUM ASSISTED
• COMPRESSED AIR ASSISTED
AIR BRAKES (Used in heavy commercial vehicles)

COMPONENTS OF THE BRAKING SYSTEM

• TANDEM MASTER CYLINDER
• WHEEL BRAKES
• BRAKE BOOSTER
• VACUUM PUMP
• PRESSURE CONTROL VALVES (G VALVE/LSPV)
• BRAKE FLUID RESERVOIR

BRAKES BRAKE FLUID RESERVOIR
MANUAL HYDRAULIC BRAKE

TANDEM MASTER CYLINDER
TYRE TYRE
BRAKE BRAKE

LSPV

BRAKE BRAKE
TYRE TYRE
G-VALVE BRAKE PIPES

EITHER G-VALVE OR LSPV IS FITETD

BRAKES
BRAKE SPLIT

FRONT/BACK SPLIT X- SPLIT

BRAKE TANDEM POWER ASSISTED BRAKE
BRAKES FLUID MASTER VACUUM (VACUUM)
RESERVOIR CYLINDER BOOSTER

TYRE TYRE
BRAKE BRAKE

VACUUM
PUMP

ENGINE LSPV

BRAKE
BRAKE
TYRE
TYRE
G-VALVE BRAKE PIPES

BRAKES
1.
1 TANDEM MASTER CYLINDER - Converts driver s foot effort to
driver’s
hydraulic pressure and transmits the pressure to wheel cylinders.

The tandem master cylinder has 2 compartments for safety . Each
compartment is connected separately and independently to either
front or rear wheel brakes. Failure of one circuit (leakage) will lead
to brake failure in that particular axle. The vehicle can be brought to
stop with the working brakes in the other axle, with higher pedal
effort.

BRAKES
2.
2 WHEEL BRAKES - Wheel brakes are fitted on each wheel Wheel
wheel.Wheel
brakes can be classified as Drum brakes & Disc brakes

DRUM BRAKES - Where a set of brake liners expand against a
brake drum leading to braking of the vehicle.The brake liners are
operated by a wheel cylinder which receives hydraulic pressure
form the tandem master cylinder.

Drum brakes are normally fitted on Front & Rear brakes

Drum brakes can be further classified as :

Simplex(HNSS) - Hydraulic Normal Shoe Sliding - Fitted at
Rear/Front
Duplex (HLSS) - Hydraulic Leading Shoe Sliding - Fitted at Front
Duo-Duplex -

BRAKE FLUID BRAKE FLUID
FROM MASTER BRAKES FROM MASTER
CYLINDER CYLINDER
DRUM BRAKES

WHEEL CYLINDER
BRAKE LINER

BRAKE DRUM

BRAKE FLUID
FROM MASTER
CYLINDER

SIMPLEX DUPLEX

BRAKES
DRUM BRAKES

BRAKE FLUID
FROM MASTER
CYLINDER
WHEEL CYLINDER

BRAKE LINER

BRAKE DRUM

BRAKE FLUID
FROM MASTER
DUO- DUPLEX CYLINDER

BRAKES
DISC BRAKES - Where a set of brake pads expand against a brake disc
leading to braking of the vehicle.The brake liners are operated by a
wheel cylinder which receives hydraulic pressure form the tandem
master cylinder.

Disc brakes are normally fitted on Front brakes

Disc brakes can be further classified as :

Fixed Caliper - Where there are separate wheel cylinders each for inner
& outer brake pad. (used in earth moving equipment)

Floating Caliper - Where there is only inner pad is moved by the wheel
cylinder , the outer pad is moved by the caliper.
y p y p

Floating caliper brakes can be further classified as :

Single pot - Where one wheel cylinder operates the inner pad
Twin pot - Where two wheel cylinders operates the inner pad

BRAKES
DISC BRAKES - FLOATING CALIPER - SINGLE POT

BRAKE CALIPER (MOVING)

BRAKE FLUID
FROM MASTER
CYLINDER

BRAKE PADS
WHEEL CYLINDER

BRAKE DISC

BRAKES
DISC BRAKES - FLOATING CALIPER - TWIN POT

BRAKE CALIPER (MOVING)

BRAKE FLUID
FROM MASTER
CYLINDER

BRAKE PADS

WHEEL CYLINDERS

BRAKE DISC

BRAKES
DISC BRAKES - FIXED CALIPER

BRAKE CALIPER (FIXED)

BRAKE FLUID BRAKE FLUID
FROM MASTER FROM MASTER
CYLINDER CYLINDER

BRAKE PADS
WHEEL CYLINDER

BRAKE DISC

BRAKES
3. BRAKE BOOSTER - Also known as Brake Servo. Brake booster is
fitted between the brake pedal and the tandem master cylinder.
Brake booster supplies additional effort to the tandem master
cylinder as soon as the brake pedal is pressed by the driver. The
additional effort is derived from the vacuum generated by the
dditi l ff t i d i d f th t d b th
vacuum pump. Brake pedal efforts are lower when equipped with
brake booster.

Brake boosters are specified by the diameter of the diaphragm - 9”
or 10”

In case of failure of the brake booster or loss of vacuum, the braking
system reverts to manual system. More effort will be required to
stop the vehicle.
p

TANDEM BOOSTER - Tandem boosters are 2 boosters of different
sizes sandwiched in to one housing.

BRAKES
AIR VALVE
VACUUM VALVE - CLOSED
- OPEN BOOSTER

BRAKE RELEASED

MASTER CYL

VACUUM FROM
VACUUM PUMP

AIR VALVE
- OPEN

VACUUM VALVE
- CLOSED

BRAKE PRESSED

MASTER CYL
ATM AIR
VACUUM FROM
VACUUM PUMP

BRAKES
AIR VALVES
VACUUM VALVES
- OPEN
- CLOSED TANDEM BOOSTER

BRAKE RELEASED
MASTER CYL
VACUUM FROM
VACUUM PUMP

VACUUM VALVES
AIR VALVES
- CLOSED
- OPEN

ATM AIR BRAKE PRESSED

MASTER CYL

VACUUM FROM
VACUUM PUMP

BRAKES
4. PRESSURE CONTROL VALVES - Pressure control valves modify
the brake fluid pressure to the rear braking circuit, under certain
circuit
conditions to avoid rear wheel locking.

When a vehicle is braked at high speeds, weight transfer happens.
The vehicle weight shifts to the front axle. There will be relatively
very less weight in the rear axles. The brake fluid pressure is same
for both front & rear axles. This will lead to “Rear Wheel Lock”
condition. A locked rear wheel will lead to vehicle instability and
skidding/Tail swing.

Pressure control valves reduce the brake fluid pressure to the rear
circuit , under these conditions. Pressure control valves are
classified as :

PCRV - Pressure Conscious Regulating Valve
DCRV - Deceleration Conscious Regulating Valve
LCRV - Load Conscious Regulating Valve

BRAKES
G-VALVE - G-valve is a deceleration conscious pressure regulating
valve, fitted on the rear brake circuit. When the vehicle is braked
hard,
hard the g-level of the deceleration is sensed by a steel ball , which
g level
rolls forward and partially blocks the brake fluid to the rear brakes.

TYRE TYRE
BRAKE BRAKE

BRAKE BRAKE
TYRE TYRE
G-VALVE

G-Valves are fitted at a specified angle in direction of vehicle motion

BRAKES
LCRV (Load Conscious Regulating Valve) - Also known as LSPV
(Load Sensitive Pressure Valve). LCRV detects the load on the
vehicle and accordingly regulates the brake fluid pressure to the rear
brakes.

Load (fully laden or unladen) is detected by height difference
between the rear axle and the body , using levers or springs.

BODY
LCRV/LSPV BODY
SPRING

UNLADEN LADEN

BRAKES
5. VACUUM PUMP - Vacuum pump generates vacuum for the
brake booster. Vacuum pumps are mounted on the rear side of
the alternator and are generally driven by the engine by a belt.

Failure of the belt will lead to vacuum pump stopping functioning
leading to loss of vacuum to the booster and hard brakes.

6. BRAKE FLUID RESERVOIR - Stores brake fluid and supplies to
tandem master cylinder. Brake fluid reservoir has 2 separate
compartments for front circuit and rear circuit
circuit.

COMFORT/CONVIENIENCE SYSTEMS

• POWER PLANT GENERATES THE POWER/TORQUE
• DRIVELINE MODIFIES & TRANSMITS THE TORQUE
• THE RUNNING SYSTEM CONTROLS THE VEHICLE

COMFORT/CONVIENIENCE SYSTEM CONSISTS OF

HVAC/AC - Provides a comfortable climate inside the vehicle
ELECTRICALS - Operates a host of electrical aggregates
INSTRUMENTS - Provides information about vehicle systems
y
AUDIO/VIDEO - Provides in-car entertainment
SEAT/UPHOLSTRY

HEATING, VENTILATION & COOLING

HVAC SYSTEM ALLOWS THE PASSENGERS TO CONTROL THE
CLIMATIC CONDITIONS INSIDE THE VEHICLE TO THEIR COMFORT
& CONVIENIENCE.

THE VARIOUS FUNCTIONS OF THE HVAC SYSTEM ARE :

COOLING - Brings down the temperature of air inside the vehicle
when the outside temperatures are very high

HEATING - Brings up the temperature of inside the vehicle when the
outside temperatures are very low.

VENTILATION - Allows to purge the stale air inside the vehicle and
bring in fresh air from outside.

(HVAC SYSTEM)
CONDENSOR
HEATER
VALVE HEATER

EVAPORATOR

AC COMPRESSOR
BLOWER
FAN
HOT AIR
ATM AIR
ENGINE
COOL AIR

CONDENSOR
FAN
W
A
R
M

A
I
R
EXPANSION
VALVE

RECEIVER-DRIER
RD BOTTLE R-134a REFRIGERANT - CFC FREE

(HVAC SYSTEM)

THE HVAC SYSTEM IS OF AIR MIXING TYPE, WHERE THE DESIRED
TEMPERATURE IS OBTINED BY MIXING THE HOT AIR FROM
HEATER & COLD AIR FROM THE EVAPORATOR.

AIR MIXING IS CONTROLLED BY ADJUSTING THE VARIOUS FLAPS
OR THE HEATER VALVE INSIDE THE HVAC UNIT.

USES R134a REFRIGERANT, WHICH IS CFC-FREE

(COOLING SYSTEM)
CONDENSOR

EVAPORATOR

AC COMPRESSOR
BLOWER
FAN

ATM AIR
ENGINE
COOL AIR

CONDENSOR
FAN THERMISTOR
W
A
R
M

A
I
R
RECEIVER-DRIER EXPANSION
RD BOTTLE THERMOAMPLIFIER VALVE
TEMP
CONTROL

BLOWER
SWITCH
R-134a REFRIGERANT - CFC FREE

(COOLING SYSTEM)

THE COOLING SYSTEM IS OF THERMO AMPLIFIER TYPE, WHERE
THE DESIRED TEMPERATURE IS OBTAINED BY SWITCHING ON &
OFF THE AC COMPRESSOR.

REQUIRED TEMPERATURE IS SET BY ADJUSTING THE
TEMPERATURE CONTROL KNOB & BLOWER SWITCH.

USES R134a REFRIGERANT, WHICH IS CFC-FREE

(COOLING + HEATER SYSTEM)
CONDENSOR

EVAPORATOR

AC COMPRESSOR
BLOWER
FAN
HOT AIR
ATM AIR
ENGINE
COOL AIR
HEATER
VALVE

CONDENSOR
FAN THERMISTOR
W
A
R
M

A
I
RECEIVER-DRIER R EXPANSION
RD BOTTLE THERMOAMPLIFIER VALVE
TEMP
CONTROL HEATER
SWITCH
BLOWER
SWITCH
R-134a REFRIGERANT - CFC FREE

1. COMPRESSOR - Compressor sucks the refrigerant from
evaporator
e aporator , compresses the same and delivers to condenser
deli ers condenser.

2. CONDENSOR - Condenser is similar to radiator , where the hot,
compressed refrigerant is cooled
cooled.

3. CONDENSOR FAN - Condenser fan sucks fresh atmospheric air
through the condenser aiding in cooling of the refrigerant inside
the condenser.

4. REECEIVER-DRIER (RD BOTTLE) - Receives the compressed
and cooled refrigerant and removes any humidity from the
refrigerant.

5.
5 EXPANSION VALVE - R Receives cooled & compressed refrigerant
i l d d fi
and expands the refrigerant and passes it in to the evaporator.
Expanded refrigerent gases are very cold

6. EVAPORATOR - Evaporator is similar to radiator. The expanded
cold refrigerant is passed over warm air from inside the vehicle.

7.
7 BLOWER - Blower fan sucks warm air from inside the vehicle
and passes it over the evaporator which has cold refrigerant on
the inner side , thus cooling the vehicle interiors.

8. HEATER - Heater is similar to radiator , where hot coolant from
the engine is circulated on the inside. Blower fan passes cold air
from the vehicle interior.

ELECTRICAL SYSTEM
THE VEHICLE ELECTRICAL SYSTEM CAN BE BROADLY
CLASSIFIED AS :

POWER GENERATION - Generation of electrical power when the
engine is running - Alt
i i i Alternator
t

STORAGE - Storage of electrical energy for use in the vehicle when
the engine is not running - Battery

TRANSMISSION & CONTROLS - Transmits & controls the power
flow to the consumers - Wiring harness, Fuses, Relays.

CONSUMERS - Electrical aggregates which consume electricity for
functioning.
g

VEHICLE ELECTRICAL SYSTEM OPERATE ON 12 V DC

ELECTRICAL SYSTEM
POWER GENERATION - P Power generation is done by the
ti i d b th
Alternator. Alternator is driven by the engine through a belt.
Alternator consists of :

Generation Unit - Generates AC power
Rectifier - Rectifies the AC and converts to DC
Regulator - Regulates the alternator output voltage to a maximum
of 14.5 Volts
VACUUM PUMP
ALTERNATOR PULLEY
Driven by engine
GENERATION

RECTIFIER REGULATOR

ELECTRICAL SYSTEM
STORAGE - The electrical energy generated by the Alternator is
stored in a Battery for use when the engine is not running. Battery
stores the energy in an electro-chemical form.

While starting the vehicle , the starter motor , takes electrical
energy from the battery. This drains the battery. As soon as the
engine is started, the alternator starts charging the battery .
started

- +

BATTERY

ELECTRICAL SYSTEM
TRANSMISSION AND CONTROLS - The electrical energy from
alternator or battery is transmitted to the various consumers
through wires. A bunch of wires is called wiring harness. Also, the
flow of electrical energy is controlled by various controls, namely,
fl f l ti l i t ll d b i t l l
Fuses, Relays, Switches etc.

ELECTRICAL SYSTEM
CONSUMERS - Consumers are electrical aggregates which
consume electricity for functioning. Some of the major consumers
are :

• LIGHTING SYSTEM
• WINDSHIELD WIPE/WASH SYSTEM
• HEATERS/DEMISTERS
• WINDOW OPERATING SYSTEMS
• DOOR LOCKING SYSTEM
• ENGINE MANAGEMENT SYSTEMS
• STARTING SYSTEM
• HVAC - BLOWER FAN/CONDENSOR FAN

VEHICLE DIMENSIONS
OVERALLWIDTH OVERALL HEIGHT OVERALL LENGTH

ANGLE OF APPROACH ANGLE OF DEPARTURE

WHEEL BASE

WHEEL TRACK GROUND CLEARANCE

VEHICLE WEIGHTS
KERB WEIGHT - The unladen weight of the vehicle - No passengers

GVW (Gross Vehicle Weight) - The fully laden weight of the vehicle
with passengers/goods.
ith / d

PAYLOAD - The difference between GVW and Kerb weight

VEHICLE PARAMETERS

GRADEABILITY - The maximum gradient a vehicle can climb, under
GVW conditions, in first gear.

GRADEABILITY , Deg

VEHICLE PARAMETERS

MINIMUM TURNING RADIUS - The radius of the circle made by the
outermost point in the vehicle, while taking a turn with maximum
wheel turning

TURNING RADIUS

Basics Of Automobile

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Basics Of Automobile