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AERODYNAMICS IN AUTOMOBILES

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SSC CGL ONLINE COACHING COURSE 2017 & 2018 (Tier 1 - 4) What is Aerodynamics ? As the name suggests , " Aero "  "dynamics" i.e. Dynamics of Air. This means that Aerodynamics is that branch of engineering that deals with the study on Forces by Air in layman language. How to study Aerodynamics ? One of the most difficult problems that students face while beginning there study on aerodynamics is ,            " Where to start from". Aerodynamics is in itself so wide a branch , that one may find it difficult to gallop the elephant at once. Thus , it has to be cut in pieces and eaten accordingly. O ne must classify his/her branch eg.    Aeronautical /Automobile and should pick up specific studies. Another problem that students face is that at times the subject can be really boring. Unlike other divisions in automobile engineering , Aerodynamics does not present itself with visuals . So, this might result in the boredom of ...

Clutch

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Clutch The clutch is housed between the engine and transmission where it provides a mechanical coupling between the flywheel and the transmission input shaft.The main purpose of the clutch is to disengage the engine from the drive line while changing gears or starting from rest,however, there are other requirements too. REQUIREMENTS: (1) Pick up load smoothly. (2) Have a driven disc of low moment        of inertia for quick shifting. (3) Damp vibrations of crankshaft. ($) Require little pressure to operate. (5) Be easy to access. (6) Be cheap to manufacture. Now, Mechanical clutches fall in two main categories positive engagement and progressive engagement . The former is either positively disengaged, so that no torque can be transmitted from the driving to the driven shaft, or positively engaged, in which case the shafts rotate together, connected by some mechanical devices such as splines, keys or dogs. In contrast, t...

CHASSIS DESIGN

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This particular blog deals with a brief introduction to chassis design. Most of the people find it very difficult to find precise and appropriate content related to chassis design . A lot also find it a little boring as it does not contain videos in it.Here, I will.. try to share some info. step wise so that you don't find it boring. First I will start with some basic types of Chassis Ladder Frame Two long beams that run the length of the vehicle and provide a strong support for weight and originally based on a carriage design. Body on frame achitecture is a good example of this type of chassis . Space Frame A nodal triangulated truss network that attempts to distribute all loads into axial directions so that no part of the frame is subjected to the harsher bending forces. A good example of this type of chassis is most Formula SAE chassis or a Lamborgini Countach. Audi Aluminum Space Frame A technology that blends mass manufactured monocoque design with large cros...

Drum Brakes

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                                       DRUM BRAKE                         PRINCIPLE  OF OPERATION- principle of operation of drum brake part-1 principle of operation of drum brake part-2 DRUM BRAKE COMPONENTS- Modern drum brakes are sometimes called internal expanding brakes, since the brake components are internal (inside a drum), and the shoes must expand, or move out­ward, to contact the drum. Drum brake components vary only slightly between manufacturers. Most design differ­ences are in the methods of brake shoe anchoring and spring placement. Backing Plate - To provide a foundation for the drum brake COMPONENTS  and to act as a splash shield against water and road  debris, a backing plate (sometimes call ed a support plate)  is used. The wheel cylinder,brake ...

Four Wheel Drive Transmission

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Four Wheel Drive Layout Typically in a Four Wheel Drive layout, a transfer box is interposed between the gearbox and back axle.The function of the transfer box, as can be comprehended, is to transfer the drive to both the front and the rear axles. In the transfer box is pinion A, see figure,driven by a coupling from the gearbox output  shaft. The pinion, through an intermediate gear B, drives a third gear C,  mounted on the cage of a differential gear assembly. From the differential  gears, one shaft is taken forward to the front axle and the other rearwards to  the back axle. Both the axles house their own differentials and final drive  gears, but that at the front carries at its outer ends the universal joints D,  which are necessary to allow the front wheels to be steered.  The differential at C, in the transfer box, is necessary to distribute the  drive equally between the front and rear axles and to allow for the...

Braking System

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History of Braking System In a little over a hundred years since the automobile took hold of people's imagination, technologies designed to make them accelerate faster and reach higher speeds have evolved with a fury the likes of which we can only see in the aeronautics industry. Still, despite chargers, turbochargers, twin turbochargers or NOX, there are limits which cannot be surpassed by a land based vehicle in terms of speed, be it because of technological limitations or the laws of physics.  Not the same can be said about the rather unseen part of the automotive evolution: brakes. The only limitations imposed to them are in connection with the human body's ability to withstand rapid deceleration. Otherwise, it would be a lot easier stopping a car than making it go insanely fast.  Whether they come in the form of drum brakes, as was the case in the dawn of the automobile, or as discs, the brakes have been the horsepower's companion throughout the...

Rear Engine Vehicles with Live Axle

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This arrangement has primary advantage in buses and coaches because it allows floor to be set at low level and to be flat and clear throughout the whole length.In the Figure 1, the engine and gearbox are made as one unit mounted transversely behind the rear axle.The clutch is interposed between these two.At the other end of box is a bevel gear pair known as the transfer drive . Now to transfer the drive to rear axle, the gear is coupled by a universal joint to a relatively short propeller shaft which is then coupled by pinion shaft to final drive unit. Obviously, the shorter the propeller shaft, the greater is the angle through  which it has to swing to accommodate the relative movements of both the  engine on its mountings and the axle on its springs. Therefore, the final drive  unit is incorporated at one side of the axle, instead of near its centre. The  drive is turned through much less than 90° from the propeller shaft at both its final drive ...

Types Of Mechanical Transmission Systems

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Most mechanical transmission fall in three basic categories with three elements each, namely- (1) Clutch, Gearbox and Live Axle, (2) Clutch, Gearbox and Dead Axle, (3) Clutch, Gearbox and Axle-less transmission Clutch, Gearbox and Live Axle --> The engine is in the front with its crankshaft parallel to the axis of vehicle.The drive is transmitted from engine through a clutch and a short shaft 'c' to the gearbox ('c' is almost always integral with the primary gear in gearbox, but sometimes is a separate component with universal joints).From the gearbox the "Propeller Shaft"-having U joints at both ends and a sliding joint at front end-takes the drive to rear live axle.Live axle is the one through which the drive is transmitted while a dead axle is the one through which the drive is not transmitted.Bevel or worm gearing (g) within the axle turns the drive through  90°, and differential gears divide it equally between the two drive shafts, or  ha...

TRANSMISSION REQUIREMENTS

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The internal combustion engine, as used in road vehicles, has the following requirements and characteristics— (1) To start it, some form of external energy must be applied. (2) Its maximum torque is small compared with that of a steam engine or electric traction motor of the same maximum horse power. (3) Its maximum power is developed at a relatively high speed – ranging from about 1700 rev/min for heavy commercial vehicles to 12000 rev/min and more in racing cars. In consequence, it must be used in conjunction with a transmission that differs in many respects from those of either steam- or electrically-powered vehicles. Various methods have been used for starting engines – for instance, from energy stored in a spring or flywheel, or chemical energy in a cartridge – but the general rule of course is to use a battery-electric starter. During starting, provision should be made to disengage engine from the drive line and consequently engaging the drive should be smooth a...

WHEELS

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They are like shining wings..sparkling jewels..the ultimate expression of an automobile...emotions and impressions are focused on them..their light alloy material is seductive..WHEELS are the finest feature of any car.

How Its Made

SHOCK ABSORBERS This video gives a better understanding on how a shock absorber is made.As in the previous post basics of a shock absorber were covered in a more theoretical approach so you may want to refer that first to absorb things easily( Shock Absorbers ).But let us revise some things, wheel vibrations causes the piston in the pressure tube to move up and down and force oil through the valve which then absorbs energy and dampens the vibrations.The mechanical energy is, thus, converted into heat energy and then dissipated into the atmosphere as a result reducing the bounce. Here is the construction of a twin tube type shocker.Both the reserve tube and the pressure tube made of steel sheets being formed into a tube by rollers one after other and welded and then cut into shock absorber lengths.One thing is to be noted that the reserve tube is compressed at the ends so as to house more oil.The valves through which oil flows are made by sintering (powder metallurgy process) ...

SHOCK ABSORBERS

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A BRIEF HISTORY  In the early 1900's, cars still rode on carriage springs. After all, early drivers had bigger things to worry about than the quality of their ride - like keeping their cars rolling over the rocks and ruts that often passed for roads. 

TYRES

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Often students and other automotive enthusiasts don't get