13-06-2012, 01:16 PM
TURBO CHARGER
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ABSTRACT
TURBOCHARGER
A turbocharger or turbo is a centrifugal compressor powered by a turbine which is driven by an engine's exhaust gases. Its benefit lies with the compressor increasing the pressure of air entered with internal combustion engines such as four stroke g the engine. This results in greater performance in its power &efficiency. They are popularly use engines working on Otto & diesel cycles. The turbocharger was invented by Swiss engineer alfredbuchi in 1905.
The engine is said to have 100% volumetric efficiency if the density of the intake air above the piston is equal to atmospheric. The main objective of a turbocharger is to improve an engine's volumetric efficiency by increasing the intake density. The compressor draws in ambient air and compresses it before it enters into the intake of manifold at increasing pressure. This results in greater mass of air entering the cylinder thus increasing power and efficiency. The impeller and turbine are the two main components of a turbo charger
INTRODUCTION
A turbocharger or turbo is a centrifugal compressor powered by a turbine which is driven by an engines exhaust gases. Its benefit lies with the compressor increasing the pressure of air entering the engine thus resulting in greater performance. They are popularly used with internal combustion engines. Turbochargers have also been found useful compounding external combustion engines such as automotive fuel cells.
It mainly consists of a turbine, compressor, centre housing rotating assembly and other optional features for its better control and efficient working. They provide greater boost and power at high altitudes. It is one of the greater advantages which make the turbocharger more popular. But boost threshold and turbolag must be controlled efficiently for its effective working.
HISTORY
In 1896 Rudolph Diesel tried to increase power of the engine by pre-compressing intake air. But turbocharger was firstly invented by Swiss engineer Alfred Buchi. His patent for a turbocharger was applied for use in 1905.Diesel ships and locomotives with turbochargers began appearing in the 1920’s. During the First World War French engineer AugusteRateau fitted turbochargers to Renault engines powering various French fighters with some success.
Turbochargers were first used in production aircraft engines in 1920’s.Aircrafts such as B-17, P-47 all used turbochargers to increase high altitude engine power. Turbocharger’s first commercial diesel truck application came in 1938 by “Swiss Machine Works Sauer”. First production application of turbocharger wasin passenger cars. It was in 1962.
TURBO V/S SUPERCHARGING
In contrast to turbochargers, superchargers are not powered by a turbine but are connected directly to an engine .Belts ,chains, direct shaft, coupled shaft, gears and electric motors are probably only a few of the many ways this is performed. Successful superchargers were developed and used during the late 1800’s.
A supercharger inevitably requires some energy to be bled from the engine to drive the supercharger. For instance, the supercharger uses up about 150 hp.For that 110 hp engine generates an additional 400 hp and delivers 1,000 hp when it would deliver 750hpa net gain of 250 hp.This is where the principal disadvantage of a supercharger becomes apparent; the internal hardware of the engine must withstand generating 1150hp.
In comparison, a turbocharger will also use 150hp to drive the compressor. It has the ability to be more efficient by utilizing the wasted energy extracted from exhaust gas and converting it into useful power to compress the intake air. It actually converts the heat of the exhaust into 150hp used to drive the compressor. In contrast to supercharging principal disadvantages of turbo charging are the back pressuring of the engine and the inefficiencies of the turbine versus direct drive.
OPERATING PRINCIPLE
The power generated by the I.C engine is directly related to the compression force exerted on the air fuel mixture. By pressurizing the intake mixture before entering the cylinder, more fuel and air molecules can be packed into combustion chamber.
COMPONENTS
The turbocharger has three main components. First a turbine, which is almost always a radial inflow turbine. Second a compressor, which is almost a centrifugal compressor. These first two components are the primary flow path components. Third, the center housing/hub rotating assembly (CHRA). Then, depending upon the exact installation and application, numerous other parts, features and controls may be required, such as