Tải luận văn:điều khiển động cơ KĐB 3 pha

Đây là luận văn rất hay, các bạn có thể tải về tham khảo tại đây:

Click vào đây

Turbocharger là gì?

WHAT IS A TURBOCHARGER?

Turbocharger là một quạt gió ly tâm được dẫn động thông qua tuốc bin sử dụng dòng khí xả của động cơ. Và được dùng để tăng áp dòng khí nạp cho động cơ.

IT IS SIMPLY AN AIR PUMP –

• Forces more air into the engine at higher than ambient pressure.

WHY DO WE NEED MORE AIR ?

DIESEL ENGINE

More Air + More Fuel = More Power More Air + Same Fuel = Cleaner Exhaust

GASOLINE ENGINE

More Air + More Fuel = More Power (Gasoline engine has closer limits on air/fuel ratio)

How does the Turbo work?

TURBINE

• A turbine wheel is driven by the otherwise ‘waste’ exhaust gases. The turbine is connected to a compressor wheel and the whole assembly rotates at speeds up to 230,000 rpm.

COMPRESSOR

• Ambient air is drawn into the turbo via an air filter, then, as it passes over the compressor wheel it accelerates up to very high speed.

• Once past the compressor wheel it passes through a ‘diffuser’ which is formed between the face of the backplate (or centre housing) and the machined face of the compressor housing.
• As it passes through this area the air moving at high speed slows down and this continues as it passes though the ‘volute’ of the compressor housing (shaped like a snail’s shell!). This turns the Kinetic energy of the moving air into high pressure air.

Turbocharger Gas & Air Flow

Turbocharger Gas & Air Flow – On Engine

Turbocharger Construction

1 Shaftwheel Assembly

• The machined shaft and investment cast turbine wheel are joined by Inertia Welding or Electron Beam Welding

• Samples of the weld tested for hardness in heat affected area
• Weld penetration checked

2 Centre Housing

• Sand castings in various material grades
• Tested for porosity and for dimensional accuracy
• Bearing bore finish is critical surface
• Some use oil squirt hole for additional cooling

3 Thrust assembly – the thrust bearing
Sintered bronze or sintered iron

• Many different designs
• 270 degree or 360 degree

3 Thrust assembly – the thrust collar

Multi function

• Controls axial movement
• Separates oil and gases (oil thrower or slinger)
• Piston ring dynamic seal

Compressor End Dynamic Seal

4 Journal bearings

• Most fully floating
• Some semi floating

• Both designs use two oil films…………………..

5 The compressor wheel

• Many different designs
• Rely on high speeds for efficiency
• Flatback and EBD

6 The CHRA

http://www.youtube.com/v/D-DYNyF02dI&hl=en_US&fs=1&rel=0&color1=0x3a3a3a&color2=0x999999&border=1
www.arturbo.co.uk