2. It is derived form of SuperCharger
Consist of turbine and a comprressor coupled in
shaft
Instead of using the power from the engine to turn
the turbine which rotates the compressor.
Turbocharges can only act at high velocity exhaust so
they need somt time to startup a cold start. This
time is called as turbo lag.
INTRODUCTION
6. The exahust from various cylinder discharged into a common
intake manifold ..at pressure higher than the atmosphere
pressuer.
Exhaust gases form all cylinder are expanded in the exhaust
valves of the engin to an constant pressure in commom
manifold it delivers to turbine
From commom intake manifold exhaust gases is supplied to
the turbine where its expand to produce mechanical work
In the turbin ,the blow down energy in the form of internal
energy of exhaust gases is converted into work
The exhaust gases are maintained at constant pressure at
inlet of turbine during whole cycle
Normally this type engin used in automobile engine
CONSTANT PRESSURE TURBOCHARGING
7. More efficient than pluse turbocharger,if the
pressure ratio is 3 or higher
The exhaust pipes are very simple for multy cylinder
engine,highly efficient turbine can be used
Engine speed is not limited by the pressure waves in
the exhaust pipes
Exhust gases is supplied to te turbine at constant
pressuer,temperature,therefor the turbine runs at
high efficiency.
ADVANTAGES
8. Scavanging is not efficient.
Inorder to maintain constant pressure, long sized
exhaust pipe is required.
It is not suitable for two stroke engine.
It does not make full use of high kinetic engine of
gases leaving the exhaust port.
This is due to very slow acceleration against low
increased.
DISADVANTAGES
10. In this type, short small cross-section pipe contact each
exhaust port to the turbine. So that much kinetic energy
associated with exhaust blow down can be utilised.
The exhaust pulses are sequential and have minimum overlap.
The flow and unsteadiness can held to acceptable level.
Then exhaust valve open and considerable part of the blow
down energy is converted into exhaust pulse.
This pulses are fed to the turbine through narrow exhaust
pulses and thermal energy into work.
It is more suitable for engine having four or more cylinders.
It is commonly used in large diesel engine.
PULSE TURBOCHARGING
11. The space required is less due to short diameter
pipe.
More efficient than constant pressure system.
Separate exhaust pipes are used so that various
cylinder do not interfere with one another.
Comparatively better scavanging is obtained at low
loads due to reduced pressure.
ADVANTAGES
12. The length of the pipe and engine speed is limited.
At higher pressure ratio in turbine, recivery of engine
is poor.
In case of the single or two cylinder engine turbine
efficency is very less.
Scavanging process is ditrubuted if the waves have to
travel long distance.
DISADVANTAGES
14. It has good part load efficency and also provides good
scavenging.
It is a good combination of constant pressure and pulse
turbochargers.
In the pulse converter different branches of manifold are
connected together in a special designed venturi junction
before turbine.
The pressure pulse is converted into kinetic energy in the
nozzle section of venturi.
It creates a suction effect in a exhuast line and helps in
scavenging process of engine.
In the diffusion section pressure gradually increases and high
pressure exhaust and supply to turbine.
It gives quick response to the engine.
PULSE CONVERTOR TURBOCHARGING
