ฝึกพูดภาษาอังกฤษด้วยเทคนิค Shadowing จากวิดีโอ: How Superchargers vs. Turbos Work

I'm Jake O'Neal, creator of Animagraffs. And  this is how superchargers vs. turbos work.

The basic function of both superchargers  and turbos is to deliver more air to an engine’s internal combustion process. The  main distinction between the two is this: superchargers are mechanically powered,  often by connection to the engine crankshaft, while turbos are powered by engine exhaust gas.

Let's look at how each unit works,  starting with a supercharger.

The supercharger type shown here sits  on top of the air intake manifold.

A serpentine belt transfers crankshaft  power to the supercharger pulley.

Pulley diameter and construction is  an easily accessible way to quickly alter supercharger performance characteristics.

A gear drive system delivers  incoming power to opposing rotors.

Outside air enters through the  air filter and intake pipe.

Interlocking rotors force  air through the supercharger.

The long fins or ridges that span the  length of the rotor shaft are called lobes.

Air exits the supercharger  through a specially shaped discharge port at the bottom of the housing.

Here are a few common supercharger types: Roots The roots type supercharger saw its  first automobile application in 1900.

The term "blower" or "blown engine" originates  from the roots supercharger’s basic function as an air blower, as opposed to  other designs that compress air.

Twin screw Twin screw type superchargers feature complex rotors with intricately designed lobes  that compress air as it moves through the unit.

This increased complexity results in better  performance, but also higher manufacturing cost.

Centrifugal Centrifugal superchargers have much in common with the turbo design concept,  though they are still mechanically driven.

They produce an exponential power curve and are  often tuned to make full boost at engine redline.

Now let's look at how Turbochargers work. The turbo connects to the engine exhaust system.

In turbo setups, the exhaust manifold may  be specially designed for turbo placement, and to handle increased heat and pressure. The turbo has two separate compartments, called the turbine section and the compressor section.

Exhaust flows through the turbine section as  exhaust heat and pressure drive the turbine or exhaust wheel. A sealed shaft connects this exhaust  wheel to the compressor wheel.

The compressor wheel pulls air in  through the air filter and intake pipe.

Its specially shaped fins force air through an increasingly smaller  chamber, building compression.

Air gets hot during intake and compression,  so most turbo setups have an intercooler between the turbo and engine intake to  get air back down to ambient temperatures.

Cooler air has greater density, serving the  goal of forcing more air into the engine.

The intercooler works something like a  radiator. Hot air passes through internal tubes as outside air rushes by for cooling. Here are some common turbo designs: Single turbo All exhaust flows through a single turbocharger.

Twin turbo A setup with two turbochargers. For example, on a 6 cylinder  engine with one turbo for each cylinder bank.

Twin scroll turbo Exhaust exits the cylinder in a pulse, with a  high pressure section followed by low pressure.

Twin scroll turbos separate cylinders into pairs  so that exhaust pulse waves do not interfere with each other, and a continuous stream of  maximum pressure exhaust reaches the turbine.

Now, let's compare superchargers  and turbos in very general terms.

Again, superchargers are powered  by mechanical energy; for example, by connection to an engine’s crankshaft, while turbos are powered by otherwise wasted heat energy from engine exhaust. Boost characteristics Roots and twin screw superchargers have "positive  displacement", meaning that they move the same amount of air for each engine revolution,  regardless of RPM. This also means that they can make boost immediately (even at low  RPMs), and have a fairly linear power curve.

Turbo setups produce an exponential power  curve. Since they are powered by exhaust, turbos take time to build turbine speed  and pressure before producing usable boost.

This delay is called "turbo lag". Efficiency Superchargers take power to make power,  and an average setup can require 40-60 horsepower to function. This doesn't mean  that overall engine efficiency is always sacrificed as some setups can increase  fuel economy when not driven aggressively.

Though turbos do increase back pressure on the  engine, they derive power primarily from otherwise wasted exhaust heat as opposed to exhaust flow  pressure. As such, they can be very efficient.

In conclusion, superchargers can  be a less complex, less expensive way to increase engine performance. They  are usually easier to tune and maintain.

Supercharges can be ideal in applications  that require predictable boost at all RPMs.

Turbos might require more peripheral parts  like oil and vacuum lines, an intercooler, custom exhaust manifolds and  exhaust piping, and so on.

Turbos can require more skill to properly  configure. However, a well tuned turbo system may be able to produce boost more efficiently  and in greater quantity than a supercharger.