Presented byPresented by ::
CHETHAN S A,
Sem. Mechanical Engg.,
B.C.E – Shravanabelagola.
2. Parts of Turbocharger
5. Turbocharger Lag
A turbocharger is a turbine driven device that increases an I.C
engine’s efficiency and power output.
Nearly 35% to 40% of heat energy supplied to engine goes in to
exhaust and will be wasted.
A part of this energy could be utilized to drive a gas turbine.
Which in turn runs a compressor and hence results in supply of
more air to the engine inlet. 3
PARTS of TURBOCHARGERPARTS of TURBOCHARGER
The different parts of turbocharger are as follows :
Exhaust gas turbine
Inlet air compressor
Inlet & exhaust manifold
Waste gate actuator
5Fig. 1: Turbocharger of a single cylinder engine
Turbine & compressor are coupled to the same shaft and are
mounted within the casing.
Turbine is attached to exhaust manifold while compressor is
attached to inlet manifold of the engine.
An intercooler is present in between the compressor and
A waste gate actuator is connected to the exhaust manifold.
An oil inlet & outlet is present in between the turbine and
compressor for lubrication. 6
The exhaust gases from the engine enters in to turbine through
Exhaust gases strikes the turbine blade and thus rotates the
Thus heat energy of exhaust gas is converted in to kinetic
Since turbine and compressors are coupled to the same shaft as
turbine rotates compressor also rotates.
Thus rotating compressor sucks atmospheric air from air inlet.7
The atmospheric air gets compressed by the compressor blades
The compressed air then enters in to the engine inlet through
Since the temperature of compressed air is high (65-95˚c) an
intercooler is provided in inlet manifold.
An intercooler reduce the temperature of compressed air & it
works similar to radiator.
Thus it maintains the density & quantity of compressed air
entering into engine.
The exhaust gases after rotating turbine blades leaves turbine
& ejected to atmosphere through muffler & silencer.
A waste gate is provided in exhaust manifold and is actuated by
waste gate actuator.
When large quantity of exhaust gas enters into exhaust
manifold waste gate actuator opens the waste gate.
Thus excess exhaust gas passes through the waste gate and
required quantity of gas enters into turbine.
Finally the gas from waste gate & turbine is ejected into
Fig. 2: 3D view of turbocharger
TURBOCHARGER LAGTURBOCHARGER LAG
It is the time period required for the exhaust gases to accelerate
the turbine & compressor.
It represents short delay period before the boost pressure
Increases thermal efficiency and power output of the engine.
Deduce emission and thus reduce air pollutants to the
Required quantity of air supply is obtained and thus complete
combustion is possible.
Minimizes fuel consumption rate .
Proper air fuel mixture is obtained.
It requires special exhaust manifold.
Blade erosion takes place due to entry of dust particles.
Larger pumping elements or nozzles are needed. This
Pressure ratio is high and it has to withstand high pressure.
It is bulky and heavy.
Poor response to load change.
Petrol powered cars like Porsche, Chevrolet.
Diesel powered cars like Mercedes Benz.
Motorcycles like Kawasaki.
In trucks and tractors.