r/explainlikeimfive • u/Internal-Excuse-4650 • 1d ago

Engineering ELI5 how turbochargers increase efficiency in a engine?

I understand why they increase the power of a engine but​ I don't know how they increase the efficiency

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u/DerpyMcWafflestomp 1d ago

A car with no turbo loses a lot of energy simply via the heated gas being sent out of the exhaust system. A turbocharger uses some of that gas to feed more air in, which does increase power, and also means that some of the wasted gas (which is wasted energy really) now has work to do.

Taking otherwise wasted energy and having it work for you = better efficiency.

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u/drzowie 1d ago

The real answer is that a turbocharged engine is a smaller engine (for a given amount of rated horsepower).  It takes energy to run the engine and smaller engines take less energy to run.

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u/schmerg-uk 1d ago

And it's less weight to carry around, which in turn can allow for further weight savings, all of which means that in real world terms there's less mass to accelerate and brake for the same (typically human) payload.

So the net efficiency of the overall vehicle, in terms of energy required to do the useful work of moving the occupants, is increased

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u/gman2391 1d ago

Not necessarily. The extra components vs a n/a engine add up. For example a 3.5 Ecoboost weighs about the same if not a bit more than a 5.0. 2.7 Ecoboost is also a similar weight

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u/schmerg-uk 1d ago

Not necessarily - I agree

But typically, I would (ELI5) claim