TURBO CHARGING AND ITS WORKING PRINCIPLES

ABSTRACT

        This paper analyses the force induction system   (turbo charging) and its working principles. It further explains the history and how a turbo charger could be used to create more power in the combustion chamber of an engine.

 

                       INTRODUCTION.

        The internal combustion engine is an air consuming machine. This is because the fuel that is burned requires air with which it can mix to complete the combustion cycle. Once the air/fuel ratio reaches a certain point, the addition of more fuel will not produce more power, but only black smoke rather the amount of power an engine can make is relative to the amount of air it can flow into the cylinders, and this can be done effectively using force induction system which is turbo charging.  

   A turbo charger is a small radial fan pump driven by the energy of the exhaust gases of an engine, a turbo charger consist of a turbine and a compressor on a shared shaft.  

 

DEFINITION OF TERMS.

•        Forced Induction: is the act of using an external air pump or compressor to force more air into the engine's cylinders than it would otherwise be able to ingest atmospherically.

•        Natural aspiration: This means without a turbo charger, using atmospheric air.

 

•        Turbo Boost: is a function of compressor speed, which itself is a function of turbine speed.

 

•        The waste gate: is a device which can bypass some exhaust gas around the turbocharger when necessary to limit boost to a pre-set value.

 

                     WORKING PRINCIPLES

 

                        TURBINE SECTION.

•        The turbine is driven by the engine exhaust gas, which enters via the gas inlet casing. The gas expands through a nozzle ring where the pressure energy of the gas is converted to kinetic energy. This high velocity gas is directed onto the turbine blades where it drives the turbine wheel,

                       COMPRESSOR SECTION.

•        On the compressor, air is drawn in through  filters, and enters the compressor wheel  axially where it is accelerated to high velocity. The air exits the impeller radially and passes through a diffuser, where some of the kinetic energy gets converted to pressure energy. The air passes to the volute casing where a further energy conversion takes place.

 

•        HOW A TURBO CHARGER COULD BE USED TO CREATE MORE POWER IN AN ENGINE.

 

•        As anyone in the business of tuning engines knows, the amount of power an engine can make is relative to the amount of air it can flow into its cylinders, and so, the way to make more power is to flow more air into the cylinders. This can be done in essentially in three ways.

•        i. The first way is to increase the physical volume of the cylinders, By having larger cylinders, more air will flow into the cylinders. This is how power is made in a large engines.

 

•        such as the  V10 Dodge Viper sports car. The ten massive cylinders in the Viper engine displace a total volume of 8.3 liters.

 

•        2. High RPM

•        The second way is to increase the ability of an engine to rev higher. By spinning fast, the pistons cycle more often, and more air can flow into the cylinders per unit time. It is in this way that an 8 cylinder 2.4 liter Formula 1 engine, revolving at close to 20,000 rpm, can produce around 750 horsepower.

 

•        3. Increased Volumetric Efficiency

•        The third way to increase power is to increase an engine's volumetric efficiency. VE is the measure of how much air actually makes it into the cylinder on an intake stroke compared to the actual volume of the cylinder.

 

•       Early 1950's, Cliff Garrett was heavily committed to the design of small turbo charger engine from 20 - 90 horse power, high speed seals, radial inflow turbines, and centrifugal compressors.

 

•       On September 27, 1954, Cliff Garrett made the decision to separate the turbocharger group from the Gas Turbine department due to commercial diesel turbocharger opportunities. That was the beginning of the new Cliff Research Industrial Division - for turbocharger design and manufacturing. Cliff Research Industrial Division was later named Cliff Automobile.

 

 

•       The Chevrolet were the first turbo-powered passenger cars, and made its way into the US market  in 1962.

 

•       After the first oil crisis in 1973, turbo charging became more acceptable in commercial diesel applications. Until then, the high investment costs of turbo charging were offset only by fuel cost savings, which were minimal. Increasingly stringent emission regulations in the late 80's resulted in an increase in the number of turbocharged truck engines, so that today, virtually every truck engine is turbocharged.

 

•       In the 70's, with the turbocharger's entry into motor sports, especially into Formula I racing, the turbocharged passenger car engine became very popular. The word "turbo" became quite fashionable.

 

 

•       The real breakthrough in passenger car turbo charging was achieved in 1978 with the introduction of the first turbocharged diesel engine passenger car in the Mercedes-Benz 300 SD, followed by the VW Golf Turbo diesel in 1981. By means of the turbocharger, the diesel engine passenger car's efficiency could be increased, with almost petrol engine "drivability", and the emissions significantly reduced.

 

•       Today, the turbo charging of petrol engines is no longer primarily seen from the performance perspective, but is rather viewed as a means of reducing fuel consumption and, consequently, environmental pollution on account of  reduced carbon dioxide emission.

 

 

       ADVANTAGES OF EXHAUST GAS TURBO CHARGING.

•        Compared with a naturally aspirated engine of identical power output, the fuel consumption of a turbo engine is moderate, and it has less exhaust emission.

    It is therefore less noisy than a naturally aspirated engine with identical output. The turbocharger itself acts as an additional silencer.

•        The turbocharger compresses intake air

     up to four times that of atmospheric pressure. This

     greater amount of dense air allows more fuel to be

     burned, thereby doubling the engine’s power output

 

                               CONCLUSION

A turbocharger is probably the most effective way to increase the performance of a given displacement engine, and will yield the highest specific output and best power to weight ratio. With many turbo charge cars hitting the market soon.

We anticipate seeing a BRZ Subaru with a turbo charging hitting the showrooms in the 2015 model year.

 

•                                                             REFERENCES

 

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•       Injection. Transactions of the SAE 2003. SAE N&V

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•       injection diesel engines Transaction of the 20. Internationals

•       Wiener Motorensymposium 6-7 mai 1999,

•       [3] Schachner, P.; Reisinger, W. : Akustische

•       Optimierung von Abgasturboladern für PKW-Dieselfahrzeuge,

•       VDI-Berichte, (1991) Heft 910, Seite 297-314

•       [4] Rebbert, M.: Simulation der Kurbelwellendynamik

•       unter Berücksichtigung der hydrodynamischen Lagerung zur

•       Lösung motorakustischer Fragen, Dissertation RWTH Aachen,

•       2000

 

 

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