Introduction to Automobile engineering department

Introduction to
Automobile
Guided By :- Prof. V. D. Thakur
Ayush R. Banait18ME005
Saurav S. Chaudhary 18ME012
Pranav M. Choudhari 18ME015
Pranav R. Mahurkar 18ME046
Harshad A. Vitonde 18ME062

What is an Automobile?
● The word Automobile is derived from towards 'Auto' and 'Mobile'
Auto is self-propelled and Mobile is the vehicle and as such the
meaning of these two words is "self-propelled vehicle.” All such
vehicle which run with their own power are called Automobile.
● Automobile Engineering is a branch of engineering which deals
with designing, manufacturing and operating automobiles

Classification of automobiles
● Automobiles can be classified into several types based on
many criteria. A brief classification of automobiles is listed
below:
a. Based on Purpose
b. Based on Load Capacity
c. Based on fuel used
d. Based on Drive of the vehicles
e. Based on type of transmission
f. Based on number of wheels
g. Based on the side of drive
h. Based on Suspension system used

Classification Based on Use
● Auto-cycle
● Mopeds
● Motor-cycle
● Scooter
● Three-wheeler
● Cars, Station wagon , Pick-up , etc.
● Buses , Ordinary and double Decker
● Trucks half body, Punjad body & special purpose bodies.

Pick up Mopeds
Car
Bus
Scooter Half Body Truck
3- Wheeler
Motor Cycle
SUV

Classification Based on Load Capacity
● HTV or HMV – e.g. Trucks, Buses, Dampers.
● LTV – e.g. Pick-up , Station wagons
● LMV – e.g. Jeeps & cars.

Classification Based on Fuel Used
● Petrol vehicle
● Diesel vehicle
● Gas vehicle
● Electric
● Steam
Petrol Vehicles
Diesel Vehicles
Electric Vehicles
Gas Vehicles

Classification Based on Drive of vehicle
● Front wheel drive e.g. Hyundai Creta
● Rear Wheel drive e.g. Mahindra scorpio
● All wheel drive e.g. Jeeps, Tata Safari

Classification Based on Transmission
● Manual Transmission
● Semi-Automatic Transmission
● Automatic Transmission
Manual Transmission
Automatic Transmission

Classification Based on number of wheels
● Two wheeler
● Three wheeler
● Four wheeler ( 4 x 2) & (4 x 4)
● Six wheeler (6 x 2) and (6 x 4)

6 X 4
4 X 2
4 X 2
4 X 4
3-Wheeler
2-Wheeler

Classification Based on position of Engine
● Engine at front e.g. Maruti Suzuki 800
● Engine at back e.g. Tata Nano
● Engine at mid of chassis

Automobile Manufacturers In India

Body
● A body is outer covering of vehicle.

Chassis
● A vehicle without body is called chassis.
● Chassis is a French word was used to denote the frame
parts or main structure of vehicle. It is a backbone of
vehicle and is made of steel. All moving parts of the vehicle
fitted on it.

Introduction to Automobile engineering department

General Assemblies of chassis
● Chassis Frame
● Front Axle
● Steering System
● Rear Axle
● Suspension System
● Transmission System
● Break System
● Electrical System
● Engine, Fuel System, Exhaust System, Cooling system.

Chassis Frame
● Made of steel section for making them strong enough to withstand the
weight
● Light in weight to reduce dead weight of the automobile.
● Generally , consists of 2 long members and 6 cross members

Front Axle
● It is fitted at front by means of spring assembly and it carry all front load.
● It supports steering wheels as well as carries parts of steering systems and
breaks.

Rear Axle
● Final unit in the suspension system.
● Carries the rear load wheels
● Transmit the Drive to rear wheels.
● To provide the drive to rear wheels at right angle.
● Differentiate the speed of rear wheels at turn.

Steering System
● It is the mechanism to steer the front wheel so that the vehicle is
properly guide to desired path.

Location of Different Parts on
Frame

Vehicle Layout
● It is defined as the location and arrangement of the main component
such as engine and drive wheels.
● It can be divided into three categories as:
a. Front wheel drive
b. Rear wheel drive
c. Four wheel drive.

Significance of Vehicle Layout
● Normally automobile manufacturers tend to make their vehicle have an
equal weight distribution for each wheel.
● The overall best weight distribution helps the car for good at
acceleration, braking and steering.
● The different layouts play an Important role in weight distribution. It
also help for handling characteristics of vehicle.
● It also concentrates the drive component on one area.

Types of Vehicle Layout
● Front Engine , front wheel drive
● Front engine, rear wheel drive
● Rear engine rear wheel drive
● Four wheel drive

Front engine, Front wheel Drive
● Engine, clutch gearbox and final drive build together to form a single
integral assembly. Normally transversal Engine Arrangement is used.
Longitudinal-mounted engine is the other possible layout.
● Weight distribution tends to be more than 50% in the front axle.
● In this arrangement the engine is fitted in the front of vehicle and
drive is given to the front wheel.
● The propeller shaft length is reduced or neglects the propeller shaft.
● The drive is transferred from engine, situated at front end, to the gear
box to the differential with the help of gear .The differential unit is
placed in the front axle.

Front engine, Front wheel Drive

Advantages
● Improves Acceleration:- Having engine, clutch, gearbox and final-
drive in the front makes the front heavy and this helps acceleration
This type of arrangement provides optimum passenger space and
a flat floor line resulting in a transverse under floor longitudinal
engine position
● No Propeller Shaft:- The propeller shaft length is reduced or
neglects the propeller shaft.
● Good grip:- Good Grip with road surface due to engine weight at
front.
The chance of wheel skidding and slipping is very much reduced.
● Reduced power required for Cooling:- Power required for the
cooling is reduced as Natural air-cooling of the radiator due to
motion of vehicle.

Disadvantages
● Traction is penalized when hill-climbing, weight moves backwards.
● Less efficient braking
● Steering radius is reduced because of drive shafts. The front
wheels have to do almost all the work (accelerate, brake. Steering)

Applications
● Generally this layout is used in Cars such as
1. Maruti suzuki
2. Toyota
3. Audi, etc

Front engine, Rear wheel drive
● Rear-wheel drive places the engine in the front of the vehicle and
the driven wheels are located at the rear, a configuration known
as front-engine, rear-wheel drive layout.
● In this layout a front mounted
engine clutch-gearbox unit
drives a beam type rear axle
supported on leaf springs
through a propeller shaft with
two universal joints
● With the help of coil springs, the front wheels are independently
spring this layout is one of the Oldest layout which remains
unchanged for many years.

Front engine, Rear wheel drive

Advantages
● Even weight distribution: Balanced weight distribution between
the front and the rear wheels providing good handling
characteristics.
● More Luggage Space: Large luggage space is provided behind
the rear seat.
● Easy Maintenance and accessibility: Easy Maintenance and
accessibility of engine, gear box is easy to access and the control
over the accelerator, clutch and choke is simple.
● Less power consumption for cooling: Radiator cooling is natural
(by air) so decreases the power require for cooling.

Disadvantages
● Reduces back seats legroom space.
● A tunnel is needed for the propeller shaft.
● Reduces boot space.
● Heavier and more expensive.
● If stuck in mud or snow it is harder to drive away than in a front
wheel drive car.

Difference Between Rear Wheel Drive And Front
Wheel Drive

Advantages
● Excellent traction is available while climbing hills.
● Larger Passenger space: A larger passenger space is available for the
given length of body.
● Very compact and accessible power and transmission assembly is provided.
● Improved Breaking: Lot of weight at the back improves acceleration and
braking, rear wheels and disc brakes can be designed to take a bigger
amount of braking due to the weight distribution to the rear end.
● Passengers are comfortable from engine noise, heat and fumes.
● Front of the vehicle provides good visibility and by designing the body to
aerodynamic shape gives good streaming lining

Disadvantages
● Tendancy of over steer: At high speed, relatively high proportions of
weight at the rear axle will make the car unstable at speed. There is a
Strong tendency for the vehicle to over steer.
● The space at the front has to be reduced to allow for the steering
lock of the front wheel.
● Space utilized for engine compartment is wasted.
● Difficulties in arrangement of the engine cooling system: Natural
cooling of radiator is not possible. Power requirement increases.
● Difficult Maintenance: Compact engine, clutch and gearbox make
servicing more difficult.

Mid-Engine rear wheel Drive
● This type of engine layout places the engine between the two axles and
the rear wheels are driven.
● The weight is equally distributed between front and rear wheel.
● This type of engine layout places the engine between the two axles and
the rear wheels are driven.
● Normally 50-50 weight distribution.

Advantages
● Good acceleration due to back weight transfer.
● Good braking.
● Neutral handling.
● Front of the car can be aerodynamically optimized.

Disadvantages
● When accelerating some steering is lost.
● Takes a lot of space.
● No back seats. Difficulties with the cooling system.

Four wheel Drive (4WD)
● To increase maneuverability of the vehicle required to travel on
rough roads this four wheel drive is provided. In this arrangement all
the four wheels of the vehicle are driven by the engine thus making
the entire vehicle weight available for traction.
● These four wheel drive vehicles are very useful on Hill station if one
of the wheel slipping or skidding then the other Axle wheel transmit
the tractive force to the vehicle. The steering of the four wheel drive
is hard to operate compared With other type of drive.
● In this arrangement all the four wheels of the vehicle are driven by
the engine thus making the entire vehicle weight Available for
traction.

Working of Four wheel Drive
● When the engine is started the power is transmitted to the rear
wheel.
● When the shifter mechanism of a transfer case is connected to the
input shaft with the big input gear, but the other shifter mechanism B
disconnects the front output shaft from the rear output shaft. In this
position, the two wheel drive with the high gear is obtained.
● Similarly the situation of four wheel drive in low gear. Obviously, four
wheel drive with low gear should be used Invariably with the low
gears on the main transmission. Also the transfer case should be
engaged with the stationary vehicle since these are not provided with
synchromesh devices.

Advantages
● Traction is nearly doubled compared to a two-wheel-drive layout.
● Handling characteristics in normal conditions can be configured to
emulate FWD or RWD.
● Gives sufficient power, this results in unparalleled acceleration and
drivability on surfaces with less than ideal grip, and Superior engine
braking on loose surfaces.

Disadvantages
● The manufacturing cost of the vehicle is high.
● More component and complicate transmission.
● Increase power-train mass, rotational inertia and power
transmission losses.
● Increased fuel consumption compared to 2WD.

Applications
● Military Vehicles
● Tata Safari
● Jeeps

Differentiate between Front and Rear Mount
Engine Vehicle

Frame
● It is an important part of Chassis
● It Is A Rigid Structure That Forms A Skeleton To Hold Other Parts
Of Chassis
● Made Of Steel
Frame

Functions of frame
● To carry load of the passengers or goods carried in the body.
● To support the load of the body, engine, gear box etc.
● To withstand the force used due to the sudden braking or
acceleration
● To withstand the stresses caused due to the bad road condition.
● To withstand centrifugal force while cornering

Requirements of Chassis, Frame and Body
● Space availability: There must be adequate space inside the body
for the passenger and luggage both.
● Stiffness: The car body may be considered a rigid beam which is
supported on wheels at each end. The car body must have
sufficient stiffness to prevent excessive sagging or bending in the
middle.
● Strength: The body must be strong enough to withstand all types
of forces to which the car is subjected, which include the weight of
the car, passengers and luggage, inertia, and side forces. It should
also be able to cope with impact loads of reasonable magnitude.

Requirements of Chassis, Frame and Body
● Protection against weather: The design of the body must be
such that the occupants and the luggage are protected from bad
weather.
● Torsional stiffness: The body should be sufficiently rigid so as to
resist twisting movement on rough roads.
● Resistance to Corrosion: The vehicle body is exposed to
corrosion throughout the life. The body should be designed such
that no moisture should be accumulated which causes rust. The
materials are used also be such that no corrosion takes place.

Frame Construction
● The frame is the main part of the chassis on which the other
automobile components are attached. It is rigid and strong
enough to support the weight of the vehicle and to withstand
stress, shocks and vibrations encountered on the roads.
● It consists of two symmetrical beams rails, or channels running
the length of the vehicle, and several transverse cross members
connecting them.
● The frame is made of box, tubular channels or U-shaped section,
welded or riveted together.

● A simplified Fig 1.3.1 represent the frame shows the longitudinal
member and cross members The frame is upswept at the rear and the
free to accommodate the movement of the axle due to springing.
● The frame is taper from the rear to the front to permit adequate
movement of steering wheel to give the smaller turning circle and
steering lock.
● Brackets or tubular or box section cross members provide supports
the body and increase torsional rigidity of the frame.
● They also provided with bumpers brackets for mounting the spring.

● The construction of frame is of box shaped tubular or steel members
welded together known as ladder frame arrangement. The complete
frame is fabricated by welding process.
● Since the commercial have to carry heavy loads. frame construction is
invariably used Because in these the ground clearance is larger and
sufficient space is available for steer the wheel.
● So the frame for these have only straight member without taper toward
the front or upswept at the front or rear.
● The engine is mounted at the front end of the frame is supported at the
three places by means of rubber pads.
● This rubber pads helps to isolate the engine from road shocks and the
body from vibrations.

Load on Chassis Frame
● Short duration load: While crossing a broken patch of road, a
vehicle acted by a heavy and suddenly applied load for short
duration.
● Momentary load or combine load: While negotiating a curve,
during braking, sudden striking a pot hole a vehicle acted upon by
a combined load for momentary duration.
● Impact loads: Due to collision of a vehicle with another object, it
is subjected to externally applied impact load.
● Inertia load: During the application of brakes, the inertia load of
short duration are applied on the vehicle.

● Static load: Loads due to chassis component like engine load,
transmission system, and suspension load, steering and body,
fuel supply system load, passenger etc. are constantly acting
on the vehicle.
● Overloads: This is the overloading of a vehicle beyond the
design capacity.
● The upward twisting forces caused by the road shock which
caused the torsional effect so torsional load or bending loads
must be taken up by frame.

Types of Frame
● Conventional Frame
● Unitized Frame
● Sub Frame

Convectional Frame
● Conventional pressed steel also known as non load carrying
frame.
● The conventional type of frame is supported on the wheel axle
by means of springs so the loads on the vehicle are transferred
to the suspension system entirely by a separate chassis.
● In this case, the body work is either being made of very flexible
material or being made stiff. The body is isolated from the
chassis deflection rubber mountings.
● In this case, the vehicle loads get concentrated round the
mounting and hence result in early failures. This construction
has almost disappeared in the case of cars..

Convectional Frame
● Here all the mechanical components are attached to it and the body
is superimposed on it These types of frame are used in commercial
vehicle and preferable in large expensive private and open cars.
● The body work is made of material like wood and completely
isolated from the frame deflection with the help of rubber
mounting. This type of frame is not much suitable to resist torsion.
● There are in general conventional type of frame is supported three
main designs for frame rails. Their cross-sections include:
1. C shaped
2. Boxed
3. Hat

C - Shaped
● By far the most common, the C-rail has been used on nearly
every type of vehicle at one time or another. It is made by
taking a flat piece of steel (usually ranging in thickness from
1/8" to 3/16") and rolling both sides over to form a c shaped
beam running the length of the vehicle.

Boxed Shape
● Originally, boxed frames were made by welding two matching C-rails
together to form a rectangular tube. Modern techniques, however,
use a process similar to making C-rails in that a piece of steel is bent
into four sides and then welded where both ends meet. Hat-shaped
cross-member in the background, C-shape rails and cross-member
in centre and a slight arch over the axle.

Hat Shaped
● Hat frames resemble a "U" and may be either right-side-up or
inverted with the open area facing down. Not commonly used
due to weakness and a propensity to rust, however they can
be found on 1936-1954 Chevroletcars. Abandoned for a while,
the hat frame gained popularity again when companies
started welding it to the bottom of uni-body cars, in effect
creating a boxed frame.

Unitized Frame
● Unitized construction also known as integral frame or frameless
construction.
● This type of construction mostly used in cars.
● In this type of construction, there is no frame and need of heavy
side member are eliminated and all the mechanical component
are attached to the body.

Unitized Frame
● These body shells are made up from pillars, rails, sills, and panels
all welded together, and a reinforcing channel-section under-frame
with an extended sub-frame
at the front is provided to
replace the chassis.
● In this case, the body shell
and under body are welded
into single unit. The under body is made of floor plates and
channel and box sections welded into single unit, In some cases
sub frame is also provided for isolation, flexibility and simplified
production. This construction gives more strength and rigidity.

This assembly replaces the frame. This decreases the overall weight compared to
conventional separate frame and body construction.

Advantages of Unitized Frame
● Cost is less
● Dead weight of the vehicle is less
● Centre of gravity of vehicle is more and gives more

Disadvantages of Unitized frame
● In case of accidents, it becomes difficult to repair, set it right
and properly align the same

Sub frame
● The various components of a vehicle are bolted directly either
on the main frame members or cross members. However,
sometimes the engine and gearbox are carried on a sub-frame
supported both the main frame usually at three points. This
arrangement helps to isolate the components from the effect
of twisting and flexing of the main frame.
● Rubber mountings are used between the engine gear box unit
and the frame to reduce the vibrations for the same reason
the body is also mounted on rubber blocks on the frame.

Sub Frame
● The chassis and the body thus make the complete vehicle
body being the super structure of the vehicle. In larger and
heavier vehicles, the chassis and the body are each made as a
separate unit and the bolted together.
● The body is usually made from a large number of steel
pressings which are welded together. The body is bolted to the
chassis at numerous point, rubber or felt strips being
interposed to damp-down vibration an. noise.

Advantages of Sub frame
● In case of accident, the front half frame can be replaced easily
for replacement instead of replacing the complete chassis
frame.
● It provides smooth ride.
● Reduced Cost of maintenance
● It can work equally well on all sizes of car.
● It simplifies production because different mechanical units
produced separately can be built-up or their sub-frame easily.

Wheel track and wheel Base
● Wheel Track:-. The distance between the centers of front
wheel is known as wheel track.
● Wheel Base:- Wheel base is the distance between the centers
of the front and rear wheels

REAR WHEEL TRACK
Front Wheel Track Rear wheel track
Wheel Base

Chassis Overhang
● In motor vehicles certain length of chassis is always extended
after the rear axle , but in bus chassis it is extended further so
that floor space increased.
Front Overhang
Rear Overhang

Functions of Body of vehicle
● The body forms the passenger compartment
● Offers storage space
● Houses the automobile's systems
● In most instances, its solid structure protects passengers from the
force of an accident.

Requirements of Vehicle Body
● It should have minimum number of component.
● It should reduce noise and withstand vibration when vehicle in
motion.
● It should be distribute the load uniformly.
● It should have long fatigue life.
● It should be light weight body.
● It provide good vision and ventilation.

Significance of Streamlining
● Streamlining in aerodynamics the contouring of an object, such
as an vehicle body, to reduce its drag, or resistance to motion
through a stream of air.
● A moving body causes the air to
flow around it in definite patterns,
components of which are called
streamlines.
● A streamline body of an automobile
is a shape given to vehicle body
which lower the friction drag as
the vehicle moves through the air.
● Drag is a force that slows down motion.

Need and Importance of Aerodynamics Aspect
● In automotive aerodynamics is the main aim to reduce drag
and wind noise, minimize noise emission and prevent
undesirable lift forces and other causes of aerodynamic
instability at high speed. Air is also considered as a fluid in this
case.
● The body shape and size of the vehicle must have acceptable
aerodynamic characteristics.
● The aerodynamic aspects will be more expensive but lowering
aerodynamic drag the fuel economy of the fastest vehicle can
be improved.

Aerodynamic Forces acting on Vehicle
● There are three forces acting on a vehicle:-
1) Air drag force acting in a direction of vehicle motion.
2) Aerodynamic lift acting vertically upward.
3) Cross wind force acting in lateral direction.

Aerodynamic Drag
● Aerodynamic means the behavior of the air motion relative to car body.
Aerodynamic drag is also called as air resistance.
● Total aerodynamic drag of a vehicle include many factors such as Form
drag is also known as pressure drag or profile drag (57%) is the drag
caused by the separation of the boundary layer from the surface and
the wake created by the separation. It is depend on the shape of body.
● Induced drag (8%) skin friction drag (10%) arises from the friction of the
air against the surface and is caused by viscous drag in the boundary
layer around the automobile body.
● Interference drag (15%) is created by mixing of airflow streamline and
cooling and ventilation drag (10%). The wake is the region of turbulent
flow downstream of the moving automobile body.

Aerodynamic Lift
● The aerodynamic lift and pitching moment are undesirable
effect. The aerodynamic lift tend to reduce the pressure
between the tyre and the ground. This causes the loss of
steering on the front axle and loss of traction on the rear axle.
● Pitching causes rear wheel lift off the ground and reduce
available traction. Ii is the rocking chair or rotating action
about the transverse axis through the vehicle parallel to
ground. Due to pinching, the front suspension moves out of
phase with the rear resulting in rocking effect in a vehicle.

Yawing
● It is vertical moment of the complete body. When complete
body of vehicle goes up and down which is known bounce or
bouncing. Depending upon the movement of front end or rear
end the bounce is known as front end bounce or rear end
bounce.

Side Force
● The imbalance of the wheel due to centrifugal force acts on
the vehicle during turning which produce a side thrust.
● To sustain that force the plane of the wheel makes some angle
with the direction of motion of the vehicle. This achieved by
the distortion of tyre which is flexible.
● The angle form during taking turn to sustain the side thrust is
known as slip angle and the force produce to counter acts the
side thrust is called as Cornering force.

Rolling Movement
● It is the movement of a vehicle about its longitudinal axis produced
due to centrifugal force act during cornering.
● During cornering, a turning couple is produced about the
longitudinal axis of the vehicle owing to centrifugal force acting at
centre of gravity and forces acting at the point of contact of road
and tyre patch. This results in a motion known as rolling.
● A combination of rolling and pitching is called diagonal pitch.
● In order to control all the above suspension movements anti-roll bar,
stabilizer, pitch and roll control bars, drolytic systems. mechanical
leveling devices etc.
are provided to a
vehicles.

1.5 Alternative Fuels: LPG and CNG
● Alternative Fuel are derived from sources other than petroleum.
● The rapid depletion of fossil fuels and increasing price of crude oil
made the researchers to search for alternative source of energy.
● The scarcity of known petroleum reserves will make renewable
energy resources more attractive.
● The most feasible way to meet this growing demand is it utilizing
alternative fuels.
● The Cities Like Delhi are greatly affected by the pollution, in which
automobile and petroleum based fuels play a vital role.

Need:
● As a result gases from fossil fuel emission have caused and
continuing to caused great damage to the atmosphere such as
greenhouse effect and acidic rain.
● Alternative fuel which are renewable and eco friendly reduce the
dependency on fossil fuels and they help to preserve the atmosphere
by reducing the emission levels.
● The burning of fossil fuels create higher levels of CO, and other gases
in atmosphere affecting the green house effect.
● The scarcity of conventional fossil fuels, growing emissions of
combustion causing pollutants and their increasing costs will make
biomass sources more attractive.
● The conventional fuel as diesel exhaust may cause cancer and other
respiratory diseases.

Fuel Characteristics:
● CNG is called compressed natural gas, and it is mainly a methane gks
which is compressed at pressure between 200 to 240 bars CNG obtained
from coal bed methane and oil wells. CNG is a good fuel substitute for
vehicles CNG is lighter than the air.
1. CNG
● LPG is called liquefied petroleum gas, and it is a mixture of propane and
butane liquefied at the temperature of 15 C and a pressure between 1.7 to 7.5
bar. Propane is automatically generated from the gas fields while natural gas
is extracted. Propane is usually used for heating, cooking or agricultural uses.
LPG is heavier than air, hence it is highly flammable LPG vehicles the gas
mixes readily with air, allowing for more complete combustion.
● LPG vehicles give a longer engine life due to its clean burning characteristics.
2. LPG

CNG Fuel Characteristics
CNG Characteristics Value
Vapour density 0.68
Auto ignition 700 C
Octane rating 130
Boiling point 162 C
Air Fuel ratio 17.25
Strong pressure 20.6 MPa
Fuel air mixture quality Good
Fuel air mixture Low

LPG Fuel Characteristics
LPG Characteristics Value
Liquid Density 509 kg/m^3
Calorific value 46.34
Boiling Point -42 C
Auto Ignition Temperature 510 C
Flame Temperature 1980 C
Flame Speed 0.4 m/s
Stoichiometric air/fuel 15.8
Octane Number 111

CNG Engine
●The CNG engine uses a second fuel tank which has to be attached to
the vehicle, and is situated in the trunk. This tanke is usually larger in
size, as it has to keep the gas used compressed.
● Construction And Working
● The pressure range may vary from
engine to engine. The driver has a
choice to run the vehicle using any
one Bei simply pressing a switch on
the dashboard. This means that the
car can alternate between the different
tanks, d fuel from either.

● A CNG vehicle is a combination of the two, contains parts of both
gasoline and CNG vehicles.
● The CNG engine uses a separate fuel tank situated in the trunk. The size
of tank is large to keep the gas compressed.
● The driver has a choice to run the vehicle using any one fuels by simply
operating a switch.
● Once the driver selects the CNG tank, the
compressed gas in the tank is sucked
through a series of highly pressured lines
until it reaches the regulator.
● The function of regulator is to control the
pressure on the gas to match the
amount of fuel needed by the fuel
injection system of the vehicle engine.

● During this the piston moves downward, This stroke is called as
induction or suction stroke. The gas and air mixture is compressed to a
required compression ratio which increases temperature and pressure
and it is ignited in the combustion chamber.
● Due to combustion large amount of heat energy is released increasing
temperature and pressure which acts on piston to move the piston
downward developing power which moves the vehicle forward.
● When pressure of gas reaches to acceptable level, the solenoid valve
allows the gas to move into the fuel injection system and mixed with nir
in the pro proportion in engine. This mixture is then enters into the
suction manifold to the engine.

LPG Engine
● The propane fuel system is a completely closed system that contains a
supply of pressurized LPG.
● Since the fuel is already under pressure, no fuel pump is needed.
● From the pressurized fuel tanks, the fuel flows to a vacuum filter fuel locK
This serves as a filter and a control allowing the fuel to flow to the engine
● The gas (propane) supplied from the fuel tank through the reducer, in
which the gas changes from the liquid to the gaseous state, is injected
into the air intake just before the turbo pump
● The mass flow rate is adjusted by gas injector controlled by an electronic
control unitęECU), which adjusts the entire system based on information
obtained from load, RPM and temperature in the exhaust system
● Construction And Working

● Exhaust Gas temperature sensor acts as safety control, if the exhaust
temperature rises, the system immediately reacts by reducing gas flow
through the computer control, the engine is not at risk for knock
combustion or abnormal wear in comparison to an engine without an
LPG system installed.
● A solenoid valve must be installed on the fuel fine in between the tank
and the engine. This valve cuts the flow of LPG when the car is running
on gasoline and when the engine is shut off It also has a filter built in
that removes any dirt that may be in the fuel.
● The carburetor mixes gaseous propane with air.
● Air flow into the engine is controlled by a butterfly valve in the venturi.
● The mixture is controlled by a fuel metering valve operated by a
diaphragm, which is controlled by the pressure in the intake manifold.
● The idle system is an air bleed, similar to a gasoline engine.

Advantages
● The fuel cost is less.
● Less pollution and more efficiency: It emits 99% less pollutants carbon
dioxide (CO,), unburned hydrocarbon carbon monoxide (CO), nitrogen
oxides (NO), sulphur oxides (SOx) and particulate matter than petrol.
● It is safer for vehicle.
● Increased life of lubricating oils, as CNG does not contaminate and
dilute the crankcase oil. No need of oil change before 193000 km and
reduce vehicle maintenance.
● Being a gaseous fuel, CNG mixes easily and evenly in air.
● Low maintenance
● High Knocking resistance
● CNG fuel systems are sealed, preventing fuel losses from spills or
evaporation

Disadvantages
● The space required for CNG cylinders and their weight about 300
pounds which is more in most of the application.
● While as compare to diesel engine compression ratio of CNG is lower,
so fuel efficiency of these engine is 10-20% lower than diesel engine.

Electric Vehicles
● In the electric car, the engine is replaced by an electric motor which
gives electrical energy from a set of batteries. Aa electric vehicle also
referred to as an electric drive vehicle, uses one or more electric
motors or traction motors for Propulsion.
● Three main types of electric vehicles exist,
1. Directly powered from an external power
station, e.g. electric train.
2. Powered by stored electricity originally from
an external power source e.g. electric boats.
3. Powered by an on-board electric, generator,
such as an engine (a hybrid electric
vehicle), or hydrogen fuel cell Electric
vehicles include electric cars.

Need of Electric Vehicles
● The fast depletion of crude oil reserves, frequent price hike and high
atmospheric pollution from the code automobile, it is the need to
reduce the use of conventional fuel in the automobile, So the use of
battery op electric and solar vehicle are the best alternative.
● The social and environmental impacts of electric and hybrid include
effects on mobility and travel, electricity supply system operation,
petroleum and other fuel consumption pollution and traffic noise.
● Hybrid electric vehicles (HEV») are alternatives to conventional
vehicles, and have a critical role in mitigating climate change and
saVing oil resources. Petroleum consumption for transportation
purposes will decline, but the benefits are dependent on the type of
fuel used to generate recharge electricity.

Working of Electric Vehicles
● The battery used in electric car is lead-acid battery whose only
disadvantage is relatively low specific energy (27-33 Wh/kg).
● Sodium- sulphur type with specific energy 78-81 Wh/kg is a good
alternative but of very high cost and its use is yet limited
● The drive controller takes powers from the batteries and delivers to
motor.
● The drive controller consists of two variable resistors operated by
accelerator pedal or brake pedal

● Accelerator pedal signal sent to drive controller through
resistor to adjust the power to be delivered to the motor.
● Two resistors (potentiometers) are used for safety
● The drive controller gets signals from both the potentiometers
but operates only if the two signals are equal.
● The drive controller takes in about 300 volts DC from the
battery set and converted into maximum of 240 volts three
phase AC to send to the same motor.

Advantages of electric vehicles
1. Rapid acceleration
2. Noise free operation:Electric vehicles typically have less noise pollution than an
internal combustion engine vehicle, whether it is at rest or in motion.
3. No exhaust fumes:Electric vehicles release almost no any air pollutants at the
place where they are operated. In addition, it is generally easier to build
pollution control systems into centralized power stations than retrofit enormous
numbers of cars. Electric vehicles emit no tailpipe CO, or pollutants such as NO,
NMHC, CO and PM at the point of use. Electric motors do not require oxygen,
unlike internal combustion engines.
4. High reliability: Due to absence of numerous engine parts, such as pistons,
connecting roads, cams, valves, clutch flywheels, starter motor, distributer, spark
plugs, valve tappers etc., electric car has high reliability

5. As moving parts are less it is Easy for maintenance.
6. Regenerative braking:When we take foot off the accelerator pedal, the motor
becomes a generator, sucking the energy of motion back into the battery. ABS
brakes are automatically applied in emergency stops. Energy spent climbing
uphill is recovered on the way down, rather than in burring up the brake linings
7. No loss of power in idling: Electric motor does not need to idle and stops, thus
avoiding the power loss during ilinin case of conventional vehicles.
8. Easy to drive:No clutch operation or gear shifts are required, Full power is
available as soon as you step on brake pedal
Continued…
...

Disadvantages of Electric cars
1. The range is limited to about 100-150
km because of the need to recharge
the batteries
2. The top speed is quite low (about 60
km per hour).
3. Life of batteries is quite short, which
means very high replacement posts.
Thus it is found that it is much
expensive per kilometer run compared
to the conventional petrol engine
vehicle.

Limitations of electric car
1. High acceleration by high torque from the motor is lowered
efficiency in the motor windings caused by the high electric
current due to higher losses in the form of Joule heating
2. This energy loss increases fourfold as the input current is
doubled, so the practical limit for sustained torque from an
electric motor depends on how well it can be cooled during
operation
3. There is always a compromise between torque and energy
efficiency. This limits the top speed of electric vehicles
operating on a single gear due to the need to limit the
required torque and maintain efficiency at low vehicle speeds

Hydrogen Fuel Cell
● A fuel cell is a device which produce electrical power through a
chemical reaction by converting a fuel (hydrogen) inte electricity.
Although fuel cells and batteries are both considered electrochemical
cells and consist of similar structure fuel cells require a continuous
source of fuel and oxygen to run similar to an internal combustion
engine needs a continuous flow of gasoline or diesel.
● A hydrogen fuel cell consists of three main
components an anode, the negative post of
the fuel cell, cathode the positive post of the
fuel cell and an polymer electrolyte
membrane to create the chemical reaction
between hydrogen gas (H2) and oxygen gas
(02) as fuel.
 Construction and working

● A polymer electrolyte membrane (Proton Exchange Membrane) permits the
appropriate ions to pass between the anode and the cathode. If the electrolyte
gave free control for all electrons or ions to pass freely, it would disrupt the
chemical reaction. At the end of the process the positively charged hydrogen
atoms react with the oxygen to form both water and heat while creating an
electrical charge.
● First, a hydrogen fuel is channeled to the anode
through flow fields. Hydrogen atoms become
ionized (stripped of electrons), and carry only a
positive charge. Then, oxygen enters the fuel
cell at the cathode, where it combines with
electrons returning from the electrical circuit and
the ionized hydrogen atoms.
● Here, the oxygen atom picks up the electrons,
then it flow through the electrolyte to combine
with the hydrogen ion. The combination of
oxygen and ionized hydrogen serve as the basis
for the chemical reaction
Continued…
...

Advantages of Hydrogen Fuel Cell
1. It play important role in providing power and storing them.
2. This fuel cell are two to three times more efficient than 1.C. engine.
3. Fuel cell can provide electrical power for remote location.
4. Fuel cells are used in both stationary and motive power and play
significant role in transportation industry. It emit only water vapour
assuming no leakage of hydrogen gas.
5. It is environmental friendly.

Disadvantages of Hydrogen fuel cell
1. It still costs a considerably more.
2. It is dangerous

Applications of Hydrogen fuel cell
1. Cars, trucks, buses, and recreational vehicles.
Material handling equipment.
2. Act as a primary power source for high volume
data centers or commercial, industrial, and
residential buildings. Backup power source to
critical computer and communication networks.
3. Generating power on-site.

Introduction to Automobile engineering department

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