Turbocharging-Basics

1. TURBOCHARGING
Shubham Patel
130040119085
6th Mech-M2

2. WHAT IS A
TURBOCHARGER?
A turbocharger,
or turbo is a turbine-
driven forced
induction device that
increases an internal
combustion engine's
efficiency and power
output by forcing extra
air into the combustion
chamber.
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3. HISTORY
The turbocharger was invented by Swiss engineer Alfred
Büchi (1879-1959), the head of Diesel engine research
at Gebrüder Sulzer engine manufacturing company
in Winterthur, who received a patent in 1905 for using a
compressor driven by exhaust gases to force air into an
internal combustion engine to increase power output, but it
took another 20 years for the idea to come to fruition.
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4. WHY TURBOCHARGERS ARE
USED?
This results in a greater mass of air entering the cylinders on
each intake stroke. The power needed to spin the centrifugal
compressor is derived from the kinetic energy of the engine's
exhaust gases. A turbocharger may also beused to increase
fuel efficiency without increasing power.
Turbochargers are widely used in car and commercial vehicles
because they allow smaller-capacity engines to have improved
fuel economy, reduced emissions, higher power and
considerably higher torque.
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5. HOW DOES IT
WORK?
In order to achieve this
boost, the turbocharger
uses the exhaust flow from
the engine to spin
a turbine, which in turn
spins an air pump. The
turbine in the turbocharger
spins at speeds of up to
150,000 rotations per
minute (rpm) -- that's about
30 times faster than most
car engines can go. And
since it is hooked up to the
exhaust, the temperatures
in the turbine are also very
high.
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6. TERMS RELATED TO OPERATING
PRINCIPLE
There are three terms related to the operating principle of the
turbochargers:
 Pressure increase (Boost)
 Turbocharger lag
 Boost threshold
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7. • Pressure increase(Boost): In automotive
applications, boost refers to the amount by which intake
manifold pressure exceeds atmospheric pressure. This is
representative of the extra air pressure that is achieved over
what would be achieved without the forced induction.
• Turbocharger lag: is the time required to change power
output in response to a throttle change, noticed as a
hesitation or slowed throttle response when accelerating as
compared to a naturally aspirated engine. This is due to the
time needed for the exhaust system and turbocharger to
generate the required boost.
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8. • Boost threshold: The boost threshold of a turbocharger
system is the lower bound of the region within which the
compressor operates. Below a certain rate of flow, a
compressor produces insignificant boost. This limits boost
at a particular RPM, regardless of exhaust gas pressure.
Newer turbocharger and engine developments have steadily
reduced boost thresholds.
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9. KEY COMPONENTS OF
TURBOCHARGER
The turbocharger has three main components:
• The turbine, which is almost always a radial inflow turbine
(but is almost always a single-stage axial inflow turbine in
large Diesel engines)
• The compressor, which is almost always a centrifugal
compressor,
• The center housing/hub rotating assembly
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10. TURBINE
• The turbine housings direct the gas flow through the turbine
as it spins at up to 250,000 rpm,
• The turbine and impeller wheel sizes also dictate the
amount of air or exhaust that can flow through the system,
and the relative efficiency at which they operate. In general,
the larger the turbine wheel and compressor wheel the
larger the flow capacity.
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11. COMPRESSOR
• The compressor increases the mass of intake air entering the
combustion chamber. The compressor is made up of an
impeller, a diffuser and a volute housing.
• The flow range of a turbocharger compressor can be
increased by allowing air to bleed from a ring of holes or a
circular groove around the compressor at a point slightly
downstream of the compressor inlet (but far nearer to the
inlet than to the outlet).
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12. CENTRE HOUSING/HUB
ROTATING ASSEMBLY
• The center hub rotating assembly (CHRA) houses the shaft
that connects the compressor impeller and turbine.
• It also must contain a bearing system to suspend the shaft,
allowing it to rotate at very high speed with minimal
friction.
• The CHRA may also be considered "water-cooled" by
having an entry and exit point for engine coolant. Water-
cooled models use engine coolant to keep lubricating oil
cooler, avoiding possible oil coking (destructive distillation
of engine oil) from the extreme heat in the turbine.
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13. TURBOCHARGING &
SUPERCHARGING
 Turbocharging is using the exhaust stream to drive a
compressor with MAP at or below 30 InHg. This is
normally for altitude compensation only
 Turbosupercharging is the use of the exhaust stream to drive
a compressor to increase MAP above 30 InHg
 Normalizers are gear driven compressors that compensate
for altitude (below 30 InHg)
 Ground-boosting is the use of a supercharger to increase
take-off horsepower
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14. APPLICATIONS
• Petrol-powered cars
• Diesel-powered cars
• Motorcycles
• Trucks
• Aircraft
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15. THANK_YOU
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