Mechanical

INTRODUCTION            With the technological enhancement a lot of new technologies are arriving in the world. Many industries got their faces due to the arrival of these technologies. An automobile technology is one of them. As a part of automobile, there are also innovations in brake. The commonly used types of brakes used in automobiles are drum and disc brakes. Various types of braking system used are hydraulic,pneumatic etc.

Definition of automobile       brake system Actually, vehicle can be regard as energy conversion device, which transfers the momentum into heat, in other words, which transfers the kinetic energy into thermal energy. The brakes are used to reduce the speed of the vehicle, and the speed of conversion determines the rate of the vehicle slows down.

INTRODUCTION      A machine consists of a power source and a power transmission system, which provides controlled application of the power. Merriam-Webster defines transmission as an assembly of parts including the speed-changing gears and the propeller shaft by which the power is transmitted from an engine to a live axle.Often transmission refers simply to the gearbox that usesgears and gear trains to provide speed and torque conversions from a rotating power source to another device. In British English, the term transmission refers to the whole drivetrain, including clutch, gearbox, prop shaft (for rear-wheel drive), differential, and final drive shafts.

Carburetion  Introduction       Spark-ignition engines normally use volatile liquid fuels. Preparation of fuel-air mixture is done outside the engine cylinder and formation of a homogeneous mixture is normally not completed in the inlet manifold. Fuel droplets, which remain in suspension, continue to evaporate and mix with air even during suction and compression processes. The process of mixture preparation is extremely important for spark-ignition engines. The purpose of carburetion is to provide a combustible mixture of fuel and air in the required quantity and quality for efficient operation of the engine under all conditions.

How a Turbocharger Works            The turbocharger has been a great source of maximizing efficiency of an internal combustion engine since the late 1920’s. Alfred Buchi was the engineer that came up with the idea to utilize the wasted energy that is expelled through the exhaust system. It was in 1915 that he created his first prototype, which failed. This however did not stop the persistent inventor. He worked on it for another 10 years before he produced the first practical, functioning turbocharger that increase efficiency of an engine by 40%.

  Thermal processing of metals and alloys      Apart from mechanical processing, metals are very often subjected to thermal processing for various reasons, like: to refine grain structure/size, to minimize residual stresses, to impart phase changes, to develop special phases over external surfaces, etc. Metals and alloys develop requisite properties by thermal processing either through grain refinement of phase changes. Thermal processing is also known as heat treatment. Heat treatment originated as an ancient art in man’s attempts to improve the performance of materials in their practical applications. In present day metallurgical practice, heat treatment has become very important for obvious reasons.

Metal forming  In these techniques, a metallic piece is subjected to external pressures (in excess of yield strength of the material) to induce deformation, thus material acquires a desired shape.

Applications and Processing of Metals and Alloys       In the materials world we are living in, when making a new device/component, most often we come across a very familiar problem. This is nothing but select the right material. As learnt in earlier chapter, selection of material can play very important role preventing failures. Selection of material for a specific purpose depends on many factors. Some of the important ones are: strength, ease of forming, resistance to environmental degradation, etc. Another dimension an engineer should be aware of it is how to tailor the required properties of materials. 

Pump            A pump is a device used to move fluids, such as liquids, gases or scurries. A pump displaces a volume by physical or mechanical action. Pumps fall into three major groups: direct lift, displacement, and gravity pumps. Their names describe the method for moving a fluid. Positive displacement pumps  loop pump          A positive displacement pump causes a fluid to move by trapping a fixed amount of it then forcing (displacing) that trapped volume into the discharge pipe.

ENGINE & WORKING PRINCIPLES           A heat engine is a machine, which converts heat energy into mechanical energy. The combustion of fuel such as coal, petrol, diesel generates heat. This heat is supplied to a working substance at high temperature. By the expansion of this substance in suitable machines, heat energy is converted into useful work. Heat engines can be further divided into two types:

Injection Molding   Injection machine  The injection machine is a machine that melt plasticize the molding material inside the heating  cylinder and inject this into the mold tool to create the molded product by solidifying inside it. The  injection machine is constructed of a mold clamping device that opens and closes the mold tool, and  device that plasticize and inject the molding material. There are several types in the injection  machine, and the difference is made by how these two devices are arranged. 

Purpose of Fuel Injection System           The performance of diesel engines is heavily influenced by their injection system design. In fact, the most notable advances achieved in diesel engines resulted directly from superior fuel injection system designs. While the main purpose of the system is to deliver fuel to the cylinders of a diesel engine, it is how that fuel is delivered that makes the difference in engine performance, emissions, and noise characteristics.

    In this system, the fuel 15 pumpedhy single high pressure mid-cylinder pump into a common rail or header through likens and low pressure or transfer pump. The pressure on the common rail ls controlled by the relief valve which is kept constant.  Due to the high pressure in common rail, the fuel is forced to ciao. of the nozzle located in the cylinders. A metered quantity of fuel is supplied to each cylinder through  nozzle by operating their fuel injection values with the help of cam mechanism driven by the crankshaft of the engine.  Advantages  Only one pump is sufficient for multi-cylinder engines.  System is simple to construct and also for maintenance.  Less maintenance cost. Variation in pump supply pressure will alfect all the cylinders uniformly. It fulfills the requirements of either                        constant load with variable speed                         constant speed with variable load    Disadvantages System requires very accurate

In this niethod, the fuel is supplied at high pressure to the combustion chamber in atdmised state.t This method requires a pump to deliver the fuel at high pressure (150 bar to 300 bar) to the fuel injector. So, the main components of this system are fuel pump and fuel injector. The fuel pump is operated by a cam which 18 mounted by a cam shah. The power required to operate the cam is taken from the engine crank shaft.This system is further classified according to the location of basic components (fuel pump and fuel injector)  and the method used to meter the fuel as  common rail system Individual pump and nozzle system Distributor system

In this method, a blast of air along with the fuel is injected into the cylinder. Before injecting, the air is compressed tn I compressor to a high pressure at 70 bar .For this, normally three stage compressors are used. A fuel pump is driven by the engine itself. The cam shaft operates the fuel pump through cam and the power required to rotate the cam shaft is taken from the main shaft of the engine through a set of gears and discharges a definite quantity of fuel into the injection valve. In this method, a blast of air along with the fuel is injected into the cylinder. Before injecting, the air is   compressed tn I compressor to a high pressure at 70 bar F or this, normally three stage compressors are used. A fuel pump is driven by the engine itself.The earn shaft operates the fuel pump through cam and the power required to rotate the cam shaft ts taken from the main shaft of the engine through a set of gears and discharge: a definite quantity of fuel into the injection valve.

          Fuel injection is the introduction of fuel in an internal combustion engine, most commonly automotive engines, by the means of an injector. All diesel engines use fuel injection by design. Petrol engines can use gasoline direct injection, where the fuel is directly delivered into the combustion chamber, or indirect injection where the fuel is mixed with air before the intake stroke. On petrol engines, fuel injection replaced carburetors from the 1980s onward.The primary difference between carburetors and fuel injection is that fuel injection atomizes the fuel through a small nozzle under high pressure, while a carburetor relies on suction created by intake air accelerated through a Venturi tube to draw the fuel into the air-stream. Methods of injection system Air injection system (or) Air blast injection system Airless(or) Solid injection system

In the context of an Internal combustion engine, the term stroke has the following related meanings:  A phase of the engine's cycle (eg compression stroke , exhaust stroke ), during which the piston travels from top to bottom or vice-versa.  The type of power cycle used by a piston engine (eg two-stroke engine, four-stroke engine).  "Stroke length", the distance travelled by the piston in each cycle. The stroke length- along with bore diameter - determines the engine's displacement.  Phases in the power cycle 4 stroke engine 2 stroke engine The phases/strokes of a four-stroke engine.  1: intake 2: compression 3: power 4: exhaust Commonly-used engine phases/strokes (ie those used in a four-stroke engine) are described below. Other types of engines can have very different phases. Induction/Intake stroke               The induction stroke is the first stroke in a four-stroke internal combustion engine cycle. It involves the downward move

          Flux-cored arc welding (FCAW or FCA) is a semi-automatic or automatic arc welding process. FCAW requires a continuously-fed consumable tubular electrode containing a flux and a constant-voltage or, less commonly, a constant-current welding power supply.   An externally supplied shielding gas is sometimes used, but often the flux itself is relied upon to generate the necessary protection from the atmosphere, producing both gaseous protection and liquid slag protecting the weld. The process is widely used in construction because of its high welding speed and it portability.

     GAS-TUNGSTEN ARC WELDING (GTAW) , also known as HeliArc and tungsten inert gas (TIG). Tungsten Inert Gas welding (TIG) is the old name for TIG welding process was developed in the late 1930s when a need to weld magnesium became apparent. The process now known as gas tungsten arc welding GTAW and the new name became popular in the technical books. TIG WELDING PRINCIPLE      In the Gas Tungsten Arc Welding (GTAW) metals are fused together by heating them by an electric arc established between a non-consumable (does not melt) tungsten electrode and the work piece. A filler metal may not be used depending on the design of the joint. The molten metal, tungsten electrode and the welding zone are shielded from the atmosphere (the air around it ) by a stream of inert gas through the welding torch. The resulting welds have the same chemical integrity as the original base metal. GTAW TIG Welding can be done in any welding position and in manual, semiautomatic and automatic modes;

         Arc welding  is a process that is used to join metal to metal by using electricity to create enough heat to melt metal, and the melted metals when cool result in a binding of the metals. It is a type of welding that uses a welding power supply to create an electric arc between an electrode and the base material to melt the metals at the welding point. They can use either direct (DC) or alternating (AC) current, and consumable or non-consumable electrodes. The welding region is usually protected by some type of shielding gas,   vapor , or slag. Arc welding processes may be manual, semi-automatic, or fully automated. First developed in the late part of the 19th century, arc welding became commercially important in shipbuilding during the Second World War. Today it remains an important process for the fabrication of steel structures and vehicles arc welding

  Gas metal arc welding (GMAW)        sometimes referred to by its subtypes metal inert gas (MIG ) welding or metal active gas ( MAG ) welding, is a welding process in which an electric arc forms between a consumable wire electrode and the workpiece metal(s), which heats the workpiece metal(s), causing them to melt and join. Along with the wire electrode, a shielding gas feeds through the welding gun, which shields the process from contaminants in the air. The process can be semi-automatic or automatic. A constant voltage , direct current power source is most commonly used with GMAW, but constant current systems, as well as alternating current , can be used. There are four primary methods of metal transfer in GMAW, called globular, short-circuiting, spray, and pulsed-spray, each of which has distinct properties and corresponding advantages and limitations. Originally developed for welding aluminium and other non-ferrous materials in the 1940s, GMAW was soon applied to steels because

MIG (Metal Inert Gas) Welding or GMAW (Gas Metal Arc Welding): Arc Welding or SMAW ( Shielded Metal Arc Welding ): TIG ( Tungsten Inert Gas ) or GTAW (Gas Tungsten Arc Welding): FCAW ( Flux-Cored Arc Welding )

      Welding  is a process of joining similar and dissimilar metals or other material by application of heat with or without application of pressure and addition of filler material. It is used as permanent fasteners. Welding is essential process of every manufacturing industries. In fact, the future of any new metal may depend on how far it would lend itself to fabrication by welding.        The weldability has been defined as the capacity of being welded into inseparable joints having specified properties such as definite weld strength proper structure. The weldability of any metal depends on five major factors. These are melting point, thermal conductivity, thermal expansion, surface condition, and change in microstructure.

1. External combustion (E.C.) Engine              It is an engine in which combustion of fuel take place outside of the engine. In this type of engine heat, which is generated by burning of fuel is use to convert the water or other low boiling temperature fluid into steam. This high pressure steam used to rotate a turbine. In this engine we can use all solid, liquid and gases fuel. These engines are generally used in driving locomotive, ships, generation of electric power etc. 2 . Internal Combustion (I.C.) Engine            It is an engine in which combustion of fuel take place inside the engine. When the fuel burns inside the engine cylinder, it generates a high temperature and pressure. This high pressure force is exerted on the piston (A device which free to moves inside the cylinder and transmit the pressure force to crank by use of connecting rod), which used to rotate the wheels of vehicle. In these engines we can use only gases and high volatile fuel like petrol, diesel