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发帖数: 11530 | 1 Engineering Explained: The Pros And Cons Of Turbochargers Vs Superchargers
Have you ever wondered what the advantages of a turbocharger are over a
supercharger? Or vice versa? Well, wonder no more, because here is the best
explanation you're likely to ever read...
Engineering Explained: The Pros And Cons Of Turbochargers Vs Superchargers -
Japanese
When designing an engine to pull in more than atmospheric pressure, tuners
often turn to forced induction. It’s one of the fastest ways to add
significant power to almost any engine, and there are two prevalent ways it
can be done: supercharging and turbocharging.
What’s the difference? A supercharger is an air compressor driven by the
crankshaft of an engine, usually connected with a belt. Alternatively, a
turbocharger is simply an air compressor driven by an exhaust gas turbine.
That’s the one key difference; a supercharger requires engine power to run,
while a turbocharger runs off waste energy created by the engine. You might
assume that because the turbo is run off waste gases that it’s more
efficient, and you’d be correct!
1. Turbocharger advantages and disadvantages:
Engineering Explained: The Pros And Cons Of Turbochargers Vs Superchargers -
Japanese
Pros:
Significant increase in horsepower.
Power vs size: allows for smaller engine displacements to produce much
more power relative to their size.
Better fuel economy: smaller engines use less fuel to idle, and have
less rotational and reciprocating mass, which improves fuel economy.
Higher efficiency: turbochargers run off energy that is typically lost
in naturally-aspirated and supercharged engines (exhaust gases), thus the
recovery of this energy improves the overall efficiency of the engine.
Cons:
Turbo lag: turbochargers, especially large turbochargers, take time to
spool up and provide useful boost.
Boost threshold: for traditional turbochargers, they are often sized for
a certain RPM range where the exhaust gas flow is adequate to provide
additional boost for the engine. They typically do not operate across as
wide an RPM range as superchargers.
Power surge: in some turbocharger applications, especially with larger
turbos, reaching the boost threshold can provide an almost instantaneous
surge in power, which could compromise tyre traction or cause some
instability of the car.
Oil requirement: turbochargers get very hot and often tap into the
engine’s oil supply. This calls for additional plumbing, and is more
demanding on the engine oil. Superchargers typically do not require engine
oil lubrication.
Here’s a quick video on how turbochargers work. Hold judgement on my
drawing capabilities, it’s the second video I ever made…
2. Supercharger advantages and disadvantages:
Engineering Explained: The Pros And Cons Of Turbochargers Vs Superchargers -
Japanese
Pros:
Increased horsepower: adding a supercharger to any engine is a quick
solution to boosting power.
No lag: the supercharger’s biggest advantage over a turbocharger is
that it does not have any lag. Power delivery is immediate because the
supercharger is driven by the engine’s crankshaft.
Low RPM boost: good power at low RPM in comparison with turbochargers.
Price: cost effective way of increasing horsepower.
Cons:
Less efficient: the biggest disadvantage of superchargers is that they
suck engine power simply to produce engine power. They’re run off an engine
belt connected to the crankshaft, so you’re essentially powering an air
pump with another air pump. Because of this, superchargers are significantly
less efficient than turbochargers.
Reliability: with all forced induction systems (including turbochargers)
, the engine internals will be exposed to higher pressures and temperatures,
which will of course affect the longevity of the engine. It’s best to
build the engine from the bottom up to handle these pressures, rather than
relying on stock internals.
Superchargers often go hand in hand with big V8s, and they’re certainly
capable of producing big power. Here’s a video on how they work:
Which do I prefer?
As an engineer, it’s difficult to not side with efficiency. Turbochargers
simply make more sense, as they improve the efficiency of the engine in
multiple ways. Superchargers are an extra demand on the engine, even if they
are capable of producing useful boost at low RPM. But if you find yourself
unable to decide, it is possible to use both simultaneously, and it’s
called twincharging.
Image source: Mercedes AMG Petronas Image source: Mercedes AMG Petronas
Where will things head in the future?
Electric turbos will likely be more common in future vehicles, where an
electric motor spools up the turbo at low RPMs, producing useful boost until
the exhaust gases are sufficient enough to power the turbo. This is exactly
what’s happening in Formula 1 with the ERS system, and it’s the solution
to the turbo’s biggest disadvantage - turbo lag. | j********a
发帖数: 1743 | |
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