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1. Chapter 11 Turbo Charging And Supercharging 1

2. Introduction 2 Turbocharger T urboc h a r ger i s basically an air p u mp driven by the exhaust gas from the engine. Location The turbocharger will installed in between the air cleaner and the intake manifold

3. 3 Purpose Turbocharger forces an additional amount of air into the engine cylinder. With more air-fuel to burn, the engine produces more combustion pressure and hence more engine power. On many turbocharged engines, power output is boosted 30% or mo re (for example, a 100 horsepower engine could produce 130 horsepower with a turbocharger). With turbocharger a smaller engine which has good fuel economy can produce high power when needed. Con…..

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5. Construction The turbocharger consists of the turbine housing, compressor housing, center housing, turbine wheel, compressor wheel, full floating bearings, waste gate valve, actuator, etc. Turbocharger 5

6. 6 Turbine & Compressor Wheels The turbine wheel and the compressor wheel are mounted on the same shaft. When the engine is running, the exhaust gases flow from the exhaust manifold to the turbine wheel. They strike the blades of the turbine, spinning it up to 100,000 rpm or higher. Si n ce the c o m p res s or is o n the sa m e shaft , it al s o sp i ns a t high speed. As the compressor spins, it forces the intake air into the engine cylinders. Since the turbine wheel is exposed directly to the exhaust gases, it becomes extremely hot and since it rotates at high speeds and must be heat resistant and durable , it is made of an ultra-heat resistant alloy. Con…..

7. Center Housing The center housing supports the turbine and compressor wheels via the shaft. Inside the housing, engine oil is circulated through channels that are provided for this purpose. Also, engine coolant is circulated through coolant channels that are built into the housing. 7 Con…..

8. 8 Full-Floating Bearings Since the turbine and compressor wheels turn at speeds of up to 100,000 rpm or higher, full floating bearings are used to ensure the absorption of vibrations from the shaft and lubrication of the shaft and bearings. These bearings are lubricated by the engine oil and rotate freely between the shaft and the housing to prevent seizing during high-speed operation. Engine oil is prevented from leaking by two ring seals or by a mechanical seal and a ring seal fitted to the shaft. Con…..

9. 9 Waste Gate Valve & Actuator The waste gate valve is built into the turbine housing . Its purpose is to reduce the boost pressure when this begins to rise too high. W h en this valve o p en s , part o f the ex h aust gas b y p a ss e s the turbine wheel and flow to the exhaust pipe. The opening and closing of the waste gate valve is controlled by the actuator. Basically, it is a spring loaded diaphragm. One side of the diaphragm is connected to the boost pressure of the compressor by means of tube. When the boost pressure goes too high, it forces the diaphragm and opens the waste gate valve. No w s o m e o f the ex h aust gas b y pa s se s the turbine b y fl o w i ng through the waste gate valve. turbine speed, thereby limiting T h is p r eve n ts inc r ease in compressor speed. This limits the boost pressure Con…..

10. 10 Intercooler (or) Charge Air Cooler Air gets hot when it is compressed. This causes the air to expand and become less dense. Heated air contains less oxygen to support combustion. To cool the air and increase its density, most turbocharged engines have a charge air cooler or intercooler which is either of the air-cooled type or water-cooled type. This is a radiator like heat exchanger that cools the air after it has been pressurized. At the same time, by lowering the temperature of the air-fuel mixture, knocking is suppressed , giving improved driveability and fuel economy Con…..

11. 11 Su p erc h a r ger The method of increasing the air capacity of an engine is known as supercharging. The device used to increase the air density is known as supercharger. It is a pressure–boosting device which supplies air (or mixture )at a higher pressure. Supercharger is merely a blower or a compressor that provides a denser charge to the engine.

12. There are three type of supercharger Centrifugal type Root’s type Vane type 12 Con…..

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14. 14 Higher power output Greater induction of charge mass Better atomization of fuel Better mixing of fuel and air Better scavenging of product Increased detonation tendency in SI engines Smooth operation and reduction in diesel knock tendency Con….. Effect of supercharging

15. 15 Thank you!