How a turbocharger works

The turbocharger has been a

great source of maximizing efficiency

of an internal combustion engine since

the late 1920’s. Alfred Buchi was the

engineer that came up with the idea

to utilize the wasted energy that is

expelled through the exhaust system.

It was in 1915 that he created his first

prototype, which failed. This however

did not stop the persistent inventor. He

worked on it for another 10 years

before he produced the first practical,

functioning turbocharger that increase

efficiency of an engine by 40%.

      Over the years however, the

turbocharger has benefitted the internal combustion engine much more than

maximizing its efficiency. It has been utilized to create massive gains in power output

of an engine compared to the amount of power achievable with a naturally aspirated

platform (no forced induction utilized). Turbocharges, utilized in the right way, can

increase a non-turbocharged motor from 200 bhp to over a 1000 bhp; with supporting modifications.

How It Works

A turbocharger is composed of 3 basic parts, a compressor, a turbine, and a

center housing. The turbine is the section of the turbocharger where the exhaust

gases of the engine are forced through to cause the turbine wheel to spin. This

rotation energy is then transferred through the center housing and into the

compressor by means of a stainless steel, or sometimes inconel, shaft. This center

housing is comprised of journal or ball bearings, depending upon the application, as

well as oil lubrication ports and drains. This allows the bearings to well lubricated, as

well as cooled, to handle the immense rotational speeds and heat that they have to

endure. Some center housings have integrated coolant passages to provide

supplemental cooling. This is not always required, but it does drastically improve a

turbochargers life, as well as protect it in circumstances where it is put under high

or prolonged demand. The compressor does exactly what it’s named for, it compresses

air.

The compressor is spun by the rotational force created by exhaust gases flowing

through the turbine. This would feed the intake side of the motor. Air is inducted

into the compressor and then compressed into the piping, feeding the air intake ports

of the motor. This creates an increased flow, as well as density, of air to be fed into

the combustion chambers of the motor.

              

  So quite simply, the more oxygen that can be forced into the motor means that

more fuel can be added to maintain a stabilized combustion. This in turn causes a

larger, more powerful combustion. Thus, increasing the power output of the motor.

  The diagram above depicts the process of utilizing the engines exhaust gases to

force clean air into the motor for combustion. In the diagram above, you may notice

a “charge air cooler” or more commonly known as an intercooler. Although not

utilized in all cases, most turbocharged platforms utilize an intercooler to cool the

compressed air back down to the ambient air temperature. This is due to the fact

that heat is transferred from the turbine of the turbocharger to the compressor by consequence of the exhaust gases flowing through it. This causes an undesired effect of heating the compressed air that is formed by the compressor of the

turbocharger. A higher temperature air becomes less dense of oxygen molecules,

which intern cause less oxygen to flow into the combustion chambers and produces a

smaller, less powerful combustion (less power output). So to counter this effect, an

intercooler is implemented to cool the air back down.

    Hopefully, this has helped you to understand the dynamics and purpose of a

turbocharger. The turbocharger seems like a simple aspect, but it can get very indepth

and specific to select the correct one for an application. They are highly

engineered to exact tolerances and flow patterns, and they are very easy to destroy

if you do not understand their limitations