2. Contents
• Types of automobiles
• Vehicle construction, Different layouts
• Chassis, Frame and Body
• Aerodynamic Drag
• Specifications
• Performance Parameters
• Bharat New Vehicle Safety Assessment Program (BNVSAP) –
Crash Test norms
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3. Automobile
• An Automobile is a self propelled
vehicle which contains the power
source for its propulsion and is used
for carrying passengers and goods on
the ground, such as car, bus, trucks,
etc.,,
3
4. Role of Automobile Engineering
• Design vehicle and components
• Manufacture
• Assemble
• Ensure smooth operation
4
7. Vehicle
Systems Attributes
• Body
• Chassis
• Powertrain
• Climate Control
• Electrical
• Cost
• Weight
• Package
• Safety
• Dynamics
• Durability
• NVH
• Styling
Vehicle Systems & Attributes
8. Vehicle System Function
Body
• Provide durable attachment for other major systems
• Provide safe and pleasant seating environment for all passengers
• Protect passengers from crashes
Chassis
• Provide capability to steer the vehicle
• Provide capability to brake the vehicle safely
• Provide isolation between road and passengers
Powertrain
• Provide capability to accelerate the vehicle by transferring
torque to wheels
• Provide capability to control vehicle speed
• Meet regulatory exhaust requirement
Climate Control
• Maintain comfortable temperature distribution for passengers
• Provide windshield defrost capability
Electrical &
Electronics
• Provide power supply where needed
• Provide desirable entertainment system
• Provide functional sensors and controls
Function of Vehicle Systems
9. Types of Automobile
The automobiles are classified according to:
• Fuel used
• Body style
• Number of wheels
• Load carrying capacity
• Transmission type
• Driving position
• Driving axle
• Position of engine
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10. Types of Automobile
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• On the basis of fuel used
– Petrol vehicle, e.g. motorcycle, scooter,
cars, etc.
– Diesel vehicle, e.g. trucks, buses, etc.
– Electric vehicle which use battery to drive
– Steam vehicle, e.g. an engine which uses
steam engine
– Gas vehicle, e.g. Hydrogen, LPG and CNG
vehicles
11. Types of Automobile
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• On the basis of body style
– Sedan, Hatchback car
– Coupe car, Station
wagon, Convertible
– Van, Special purpose
vehicle, e.g. ambulance,
milk van, etc.
– Truck, Tanker, Delivery
van, Pick-up truck, Mini
load van.
– Motor Bike, Auto,
Passenger van, Bus etc.
12. Types of Automobile
• On the basis of wheels
– Two wheeler vehicle, for
example : Scooter, motorcycle,
scooty, etc.
– Three wheeler vehicle, Ex: Auto
rickshaw
– Three wheeler scooter for
handicaps and tempo, etc.
– Four wheeler vehicle, Ex: Car,
jeep, trucks, buses, etc.
– Six wheeler vehicle, Ex: Big
trucks with two gear axles
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13. Types of Automobile
• On the basis of Load
– Heavy transport vehicle (HTV) or heavy motor vehicle (HMV)
– Light transport vehicle (LTV), Light motor vehicle (LMV)
• On the basis of Transmission
– Conventional vehicles with manual transmission
– Semi-automatic
– Automatic: In automatic transmission, gears are not required
to be changed manually
• On the basis of Drive
– Left hand drive
– Right hand drive
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14. Types of Automobile
• On the basis of Driving Axle
– Front wheel drive
– Rear wheel drive
– All wheel drive
• Position of Engine
– Engine in Front - Most of the vehicles have engine in the
front
– Engine in the Rear Side - Very few vehicles have engine
located in the rear. Example: Nano car
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15. Vehicle Components
• Part or Component refers to the smallest units on a vehicle
• An assembly is several parts that fit together
• Panel refers to a large removable body part
• Pan refers to a floor-related component
• Chassis includes everything under the body, consisting of the
mechanical systems that support and power the car
16. Main Components of an Automobile
• Frame
• Chassis
• Body
• Power unit
• Transmission
system
Chassis = Frame +
Base components
Vehicle = Chassis +
Body 16
17. Important Structural Parts of an Automobile
Chassis
• If the frame contains the base components its called as chassis
• The components are like Engine, radiator, clutch, gearbox,
silencer, road wheels, fuel tank, wirings, differential units, etc..,
Frame
• The frame is the skeleton of the vehicle. It servers as a main
foundation and base for alignment for the chassis
• Types
– Body-over-frame or full frame
– Semi integral frame
– Integral or unibody frame
Body
• Body is the superstructure of the vehicle and it is bolted to the
chassis
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18. Chassis
• Chassis is derived from French term which means frame or
main structure of a vehicle
• In automobile, chassis is the external structure of the vehicle
which houses all the components of the vehicle and mounted
on the wheels of vehicle with help of frame
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20. Components of Chassis
• Frame
• Front suspension
• Steering mechanism
• Silencer
• Storage battery
• Rear springs
• Road wheels
• Shock absorbers
• Brakes and braking system
• Propeller shaft
• Engine, clutch, gearbox
• Radiator
• Fuel tank
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21. Chassis Layout of Vehicles
Front Engine
• Better protection
• Better cooling
22. Rear Engine
• Clutch, gearbox and final drive
• Independent rear suspension system
• Tail heavy
• Handling will be difficult due to high speed
• Large amount of space.
• Increase load will provide better grip on road
23. Central or Mid-Engine
• Used in sports car
• Location of engine provide excellent weight distribution
• Good handling and maximum traction from driving
wheels
• Disadvantage in traditional cars
• Two seat
24. Front Engine, Front Wheel Drive
Advantages
• Road holding is improved in wet and slippery conditions
• Passenger and cargo spaces are good because no need
of transmission shaft
• Good road adhesion is obtained
• Lower flat floor line is provided
• Provide more comfort
25. Front Engine, Front Wheel Drive
Disadvantages
• Acceleration is affected because the load transfer to rear of
the vehicle
• Complicated drive shafts are needed for CV
• Special universal joints and more complicated assembly
required due to short distance of transmission
• Possible for skidding under heavy brake
26. Front Engine, Rear Wheel Drive
Advantages
• Reasonably balanced weight
distribution between front and rear
• A large luggage space is available
• Control linkages such as choke, clutch
and gear box are short and simple
• Cooling by wind
Disadvantages
• Noise and vibration by universal joint and
propeller shaft
• Propeller shaft operation need floor
tunnel clearance
• When stuck in mud, tends to plough into
ground
27. Rear Engine Rear Wheel Drive
Advantages
• Short line drive
• Improved traction in rear wheels
• Effective rear wheel braking
• Absence of drive shaft give more floor space
• Front of the vehicle can be designed for good visibility
• This drive arrangement results a compact car
Disadvantages
• Vehicle affected by side winds at high speed
• Difficult to accommodate the liquid cooling
• Difficult to fix fuel tank in a safe zone
• Space for luggage is reduced
• Natural air cooling is not possible
• Steering is difficult in slippery conditions
28. Advantages
• Increased traction
• Wear of tyres and other
components are evenly shared
• Easily recover when it struck in
mud
Disadvantages
• Increase weight, cost, fuel
consumption, maintenance
• Difficult to accommodate ABS
Four Wheel Drive
29. Frames
There are three types of frames :
(a) Conventional frame,
(b) Semi-integral frame, and
(c) Integral frame (or unit frame).
30. Conventional Frame
• This suspension in the main skeleton
of the vehicle which is supported on
the axles through springs.
• The loads of the vehicle are
transferred to the suspensions by the
frame.
• The body is made of flexible material
like wood and isolated frame by
inserting rubber mountings in
between.
• The frame is made of channel section
or tubular section or box section.
32. Ladder Frame
• So named for its resemblance to a ladder, the ladder frame is
the simplest and oldest of all designs
• It consists merely of two symmetrical rails, or beams, and cross
member connecting them
• Originally seen on almost all vehicles, the ladder frame was
gradually phased out on cars around the 1940s in favour of
perimeter frames and is now seen mainly on trucks
• This design offers good beam resistance because of its
continuous rails from front to rear, but poor resistance to torsion
or warping if simple, perpendicular cross members are used
• The vehicle's overall height will be higher due to the floor pan
sitting above the frame instead of inside it.
33. Ladder Frame
• Channel Section - Good
resistance to bending
• Tabular Section - Good
resistance to Torsion
• Box Section - Good
resistance to both bending
and Torsion
34. Perimeter Frame
• Similar to a ladder frame, but the middle sections of the
frame rails sit outboard of the front and rear rails just behind
the rocker panels/sill panels
• This was done to allow for a lower floor pan, and therefore
lower overall vehicle in passenger cars
• This was the prevalent design for cars in the United States, but
not in the rest of the world, until the uni-body gained
popularity and is still used on US full frame cars
35. Perimeter Frame
• Perimeter frame allowed the annual model changes introduced in the
1950s to increase sales, but without costly structural changes.
• In addition to a lowered roof, the perimeter frame allows for more
comfortable lower seating positions and offers better safety in the event
of a side impact
• However, the reason this design isn't used on all vehicles is that it lacks
stiffness, because the transition areas from front to centre and centre to
rear reduce beam and torsional resistance, hence the use of torque boxes,
and soft suspension settings.
36. Semi-Integral Frame
• Half frame is fixed in the front end on which the engine,
gearbox and front suspension are mounted so that the
complete front portion can be repaired and replaced easily in
case of accidents
• The rubber mountings used in conventional frame between
frame and suspension are replaced by more stiff mountings
• Popular in Fiat cars and other European and American cars
37. Sub Frame
• The sub frame, or stub frame, is a boxed frame section that
attaches to a unibody. Seen primarily on the front end of cars,
it's also sometimes used in the rear.
• Both the front and rear are used to attach the suspension to
the vehicle and either may contain the engine
and transmission.
• The most prolific example is the 1967-1981 Chevrolet Camaro.
39. Integral or Frame-less Construction
• In this type of construction, there is no frame. It is also called
unitized frame-body construction.
• In this case, the body shell and underbody are welded into
single unit. The underbody is made of floor plates and
channel and box sections welded into single unit.
• This assembly replaces the frame. This decreases the overall
weight compared to conventional separate frame and body
construction.
40. Backbone Tube Frame
• Backbone chassis is a type of an
automobile construction
chassis that is similar to the
body-on-frame design.
• Instead of a two-dimensional
ladder type structure, it
consists of a strong tubular
backbone (usually rectangular
in cross section) that connects
the front and rear suspension
attachment areas. A body is
then placed on this structure.
41. Superleggera
• An Italian term (meaning "super-
light") for sports-car construction
using a three -dimensional frame that
consists of a cage of narrow tubes
that, besides being under the body,
run up the fenders and over the
radiator, cowl, and roof, and under
the rear window
• It resembles a geodesic structure
• The body, which is not stress-bearing,
is attached to the outside of the
frame and is often made of
aluminium
42. Various Loads acting on the Frame
• Short duration Load - While crossing a broken patch
• Momentary duration Load - While taking a curve
• Impact Loads - Due to the collision of the vehicle
• Inertia Load - While applying brakes
• Static Loads - Loads due to chassis parts
• Over Loads - Beyond Design capacity
45. Requirements of Vehicle Body
• The body should be light
• It should have minimum number of components
• It should provide sufficient space for passengers and luggage
• It should withstand vibrations while in motion
• It should offer minimum resistance to air
• It should be cheap and easy in manufacturing
• It should be attractive in shape and color
• It should have uniformly distributed load
• It should have long fatigue life
• It should provide good vision and ventilation
46. Types of Vehicle Body
According to Chassis design the body can
divided into
a) Conventional Type / Full Frame
b) Integral Type
c) Semi- Integral Type
47. Types of Vehicle Body
According to other usage:
a) Light vehicle Bodies - cars, jeeps
b) Heavy vehicle Bodies – Busses, Lorries
c) Medium vehicle Bodies - Vans, Metadoors
48. Full Frame or Body-over-frame
• Body-over-frame vehicles have separate body and chassis
parts bolted to the frame
• Full frame vehicle is heavier - high amounts of energy are
absorbed by the frame in a collision
• Torque boxes allow some twisting to absorb road shock and
collision impact
• Cross members extend sideways across frame rails to support
the engine, suspension, chassis
• Full- or partial-frame construction is used on most full-size
and some small pickup trucks
49. Body-over-frame Construction
• Frame is an independent separate
part
• Perimeter frame has a frame rail
near the outside of the vehicle, and
is the most common
• Ladder frame has long frame rails
with a series of straight cross
members, and is seldom used
• Partial frame is a cross between a
solid frame and a unibody where
Sub-frame assemblies are used at
the front and rear while the
unibody supports the middle area
Body-over-frame construction,
commonly used in large trucks
and SUVs
50. Unibody Construction
• Unibody construction uses body
parts welded and bolted together
– Uses lighter, thinner, high-strength
steel alloys
• Body shell is formed by welding
sheet metal into a box- or egg-like
configuration
– Strength is achieved through shape
and design instead of mass and
weight
• Stressed hull structure disperses
force over the entire body shell
Unibody construction welds major
body panels together to form the
frame for attaching the engine,
drivetrain, suspension, and other
parts. This type of construction is
commonly used in cars
51. The suspension and braking systems bolt directly
to the body on a vehicle with unibody construction
Unibody Construction
53. Space Frame Construction
• Space frame vehicle has a metal body structure
covered with an outer skin of plastic or composite
panels
• Roof and quarter panels may be attached with
mechanical fasteners or adhesives
• After a collision a space frame is more likely to have
hidden damage, or hidden corrosion
• Support members are bolted to unibody bottom
– Needed in high-stress areas to reduce body flex
54. Space Frame Construction
Space frame construction. Composite (plastic) panels fasten to
a metal inner body structure. Composite panels can be made
flexible to resist door dings and small dents.
55. Joining Vehicle Parts Together
• Fastened parts are held together with fasteners
• Welded parts are permanently joined by welding
• Press-fit or snap-fit parts use clips or an interface to fit parts
together
• Adhesive-bonded parts use high-strength epoxy or special
glue to hold parts together
• Composite unibody is made of plastics and other materials by
Keeping metal parts to a minimum cuts weight while
increasing strength and performance
56. Resistance to Vehicle Motion
1. Air resistance or aerodynamic drag:
A vehicle travelling at a particular speed in air
encounters a force resisting its motion. It is called
drag. Air drag depends on:
(a) Size of the vehicle
(b) Shape of the vehicle
(c) Speed of the vehicle
(d) Wind velocity
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57. Drag , Lift and Down Forces
• Frontal pressure is reduced by minimizing exposed frontal
surface area and making front end smooth
• Continuous curve originating from the line of bumper
allowing the air molecules to pass smoothly
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58. Resistance to Vehicle Motion
2. Gradient resistance
– Component of the vehicle weight
which is parallel to the plane of
the road
– When the vehicle travels uphill, a
component of its weight works in
a direction opposite to its motion
– If some energy is not supplied to
overcome this backward force,
then the vehicle would slow down,
stall and roll backwards
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59. Resistance to Vehicle Motion
3. Rolling resistance: of tyres on hard surfaces
is due to hysteresis in the tyre-material
a) Tyre rolling resistance
b) Road resistance
c) Resistance due to tyre slip angle
d) Resistance due to bearing friction and residual
braking
e) Inertia resistance
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60. Resistance to Vehicle Motion
4. Inertia Resistance
• In addition to the driving resistance inertia forces occur during
acceleration and braking
• Total mass of the vehicle & inertia mass are the factors
influencing the resistance to acceleration
• Moment of inertia of the drive elements of engine, clutch,
gearbox, drive shaft including all the road wheels are reduced
to the driving axle
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61. Tyre Rolling Resistance
Rolling Resistance composed primarily of
1. Resistance from tire deformation ( 90%)
2. Tire penetration and surface compression ( 4%)
3. Tire slippage and air circulation around wheel ( 6%)
4. Wide range of factors affect total rolling resistance
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62. Wind Tunnel Testing
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• Wind tunnels are used to test the aerodynamics of many
objects, including automobile vehicles. A vehicle is kept inside
the wind tunnel and high velocity air is allowed pass over the
vehicle. The drag force is calculated by measuring the pulling
force of wind on the vehicle
63. Open Type Wind Tunnel
63
• Air is taken from atmosphere at inlet and it is allowed to go to
atmosphere after passing through the test chamber
• The walls of the tunnel are kept smooth to avoid turbulence
• Most wind tunnels are also moderately sized for need
• Small tunnels to test scaled down models and parts
64. Closed Type Wind Tunnel
64
• Air flow is
recirculated through a
circular passage
• Contains five basic
sections, namely the
settling chamber,
contraction cone, test
section, diffuser and
drive section
• Provide more smooth
airflow in test
chamber
• Saves energy
65. • A snapshot of a vehicle's important details
• Provided by vehicle manufacturer
• Usually a published information about a vehicle
• Gives information on vehicle construction, operation,
performance and features
• Easy to compare different vehicles while purchasing
• Mostly includes:
– Dimensional specifications
– Engine specifications
– Capacity specifications
– Performance specifications
– Safety specifications
– Drivetrain, brakes, and suspension specifications
65
Vehicle Specifications
67. Torque is measured using a dynamometer.
Load cell
Force F
Stator
Rotor
b
N
The torque exerted by the engine is: T = F b with units: J
The power P delivered by the engine turning at a speed N and
absorbed by the dynamometer is:
P = T = (2 N) T w/units: (rad/rev)(rev/s)(J) = Watt
Note: is the shaft angular velocity with units: rad/s
Engine Torque and Power
68. There is a maximum in the brake power
versus engine speed called the rated
brake power.
At higher speeds brake power decreases as
friction power becomes significant compared
to the indicated power
There is a maximum in the torque versus
speed called maximum brake torque (MBT).
Brake torque drops off at:
• Lower speeds do to heat losses
• Higher speeds it becomes more difficult
to ingest a full charge of air
Max brake torque
1 kW = 1.341 hp
Rated brake power
Power and Torque versus Engine Speed
69. • For transportation vehicles fuel economy is generally given as mpg, or
liters/100 km
• In engine testing the fuel consumption is measured in terms of the fuel
mass flow rate mf
• The specific fuel consumption, sfc, is a measure of how efficiently
the fuel supplied to the engine is used to produce power,
bsfc = mf / Wb isfc = mf / Wi w/units: g/(kW hr)
• Clearly a low value for sfc is desirable since at a given power level less
fuel will be consumed
Specific Fuel Consumption
76. Electric Vehicle Performance
Electric vehicle performance comparison:
76
• Vehicle battery effectiveness ranges 4.1-5.6 km/kWh depending upon
overall vehicle size and design
77. Bharat New Vehicle Safety Assessment Program (BNVSAP)
• Also called Bharat NCAP (New Car Assessment Program) 10th world’s NCAP
• Launched in October 2023, provide safety star ratings to the cars in India
• Within two years of implementation, new cars sold in India will need to
comply with voluntary star ratings based on crash safety performance tests
• Critical safety features such as airbags, ABS, and seat belt reminders will
become standard in cars sold in India resulting from rankings and
mandatory crash testing
• Offset front crash, side, and pole impact test will be conducted
• Cars will gradually have to meet more stringent norms such as pedestrian
protection, whiplash neck injury and child restraint systems standards
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78. Bharat NCAP - Crash Test Norms
• Car crash worthiness is very important as India has seen more road deaths
per year than any other nation since 2006, costing lives at the rate of
230,000 annually.
• Bharat NCAP 2023 is similar to Global NCAP 2023,[10] which is based on
Latin NCAP 2016
• Bharat NCAP started the official testing from December 2023 onwards.
• The car testing protocols is defined by the Automotive Research
Association of India (ARAI) and published in AIS 197.
(AIS-Automotive Industry Standard)
• The impact test includes:
– Offset Deformable Barrier (ODB) Frontal Impact Test (64 km/h speed)
– Mobile Deformable Barrier (MDB) Side Impact Test (50 km/h speed)
– Pole Side Impact Test (29 km/h speed)
• Points would be awarded to the car based on crash test results and the
safety features in the car like ABS, seat belt reminders, child lock, and
Electronic Stability Control.
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81. 1. Explain about different types of automobiles.
2. Briefly explain on construction of a vehicle with neat sketch.
3. Discuss different chassis layouts of an automobile based on engine and
drive axle positions with their merits and demerits.
4. Explain different types of frames used in vehicles with their merits.
5. Discuss different types of automobile bodies and discuss their
characteristics.
6. Discuss about the air resistance to vehicle motion and its measurement
techniques.
7. Discuss about different vehicle specifications of ICE, hybrid and electric
vehicles.
8. Explain about different performance parameters of automobiles .
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