![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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Unit 1 - Automobile Engineering - Intro.pdf
- 1. ME 5691 Basic Automobile Engineering Open Elective Unit 1 - Introduction
- 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 2
- 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
- 5. Vehicle Development Organization Product Engineering Vehicle Engineering Styling Body Engineering Chassis Engineering Powertrain Engineering Climate Control Engineering Electrical Engineering Package Engineering Weight Engineering Safety Engineering Vehicle Dynamics Vehicle Durability Vehicle NVH Vehicle Thermal & Aero Prototype Planning/Test Exterior Styling Interior Styling Vehicle Development Process
- 6. Vehicle, System & Component Spec Production Design & Testing Prototype Design & Testing Program Approval Concept Evaluation To Meet Spec Fix Problems Before Production Vehicle Development Process
- 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 9
- 10. Types of Automobile 10 • 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 11 • 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 12
- 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 13
- 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 14
- 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 17
- 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 18
- 19. Chassis - Construction Chassis Construction
- 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 20
- 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.
- 38. Sub Frame - Construction
- 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
- 43. Vehicle Body
- 44. Vehicle Body Construction Vehicle Body Types
- 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 56
- 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 57
- 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 58
- 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 59
- 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 60
- 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 61
- 62. Wind Tunnel Testing 62 • 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
- 70. Vehicle Battery Energy Density Fig: Energy Density of different types of batteries 70
- 71. Vehicle Battery Capacity Fig: Battery capacity of different types of vehicles 71
- 72. • Fuel Economy • Acceleration • Top Speed • Ride Comfort • Handling Characteristics • etc. 72 Vehicle Performance Parameters
- 75. Engine Performance 75 High-performance vehicles usually offer great speed and power
- 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 77
- 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. 78
- 79. Bharat NCAP - Crash Test Rating Example 79
- 80. Links • Vehicle frame: https://www.youtube.com/watch?v=qfkTVYJIx8Q • Body types: https://www.youtube.com/watch?v=ghsXaJtc8zg • Aerodynamics: https://www.youtube.com/watch?v=jOG6RSjIEEs • Bharat NCAP Crash Testing: https://www.youtube.com/watch?v=fZRnr-7E6c4 80
- 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 . 81 Test your learning