The document provides a comprehensive overview of an engine's exhaust system, including components like mufflers, catalytic converters, and turbochargers, detailing their function and operation. It highlights the role of the exhaust system in managing emissions, reducing noise, and enhancing engine performance. Additionally, the document addresses the importance of service and maintenance to prevent issues such as rust and backpressure.

1. Welcome
Presentation Topic:
Exhaust System of an Engine
Md Sujon Babu
ID: 15207019

2. Contents
• Introduction of exhaust system
• Describe the parts and operation of exhaust system
components
• Understand the operation of a muffler
• Understand the operation of a catalytic convertor
• Understand the operation of a Resonator
• Understand the operation of a heat shield
• Turbocharger and its operation
• Discuss about turbocharger
• Question-answer session

3. Introduction of exhaust system
An Exhaust system is usually piping used to
guide reaction exhaust gases away from a
controlled combustion inside an engine or
stove. The entire system conveys burnt gases
from the engine and includes one or more
exhaust pipes.

4. Introduction ( cont.)
Depending on the overall system design, the
exhaust gas may flow through one or more of
• Cylinder head and exhaust manifold
• A turbocharger to increase engine power
• A catalytic converter to reduce pollution
• A muffler or silencer to reduce noise.

5. Exhaust system fundamentals
• Exhaust system functions
– Carries burned exhaust gases away from the
passenger compartment
– Quiets the engine
– Most new cars have one or more catalytic converters
• Excessive backpressure
– Reduces performance and fuel economy
• Exhaust system flow
– Not severely affected by bends in the pipe

6. Exhaust system fundamentals
• Mounted to cylinder head's exhaust ports
– Typically made of cast iron or steel
• Exhaust temperature
– Related to the amount of load on the engine
• Headers
– Aftermarket manifolds made of tube steel
– Sometimes require modification to install

7. Exhaust Manifold
• Fastens over the exhaust ports to carry burned
gases into the exhaust system
• Connects the cylinder head exhaust ports to a
header pipe
• Can be made of heavy cast iron or lightweight
aluminum or stainless steel tubing

8. Exhaust Manifold

9. Exhaust system of an engine

10. Cross Flow Head
This shows how the burnt gases comes out from the
engine cylinder.

11. Exhaust pipes
There are three types of exhaust pip
• Header pipe
• Intermediate pipe
• Tail pipe
Usually made of rust-resistant tubing so we have to
make sure the pipes are cleared of any obstructions
and clogs.

12. Muffler
Sheet metal chamber that dampens pressures
pulsations to reduce exhaust noise.
This is used conjunctions with a resonator.
Service
• To ensure proper function, listen for a rattling noise
when the car accelerates.
• Check for rust.

13. Muffler

14. Catalytic Converter
• An enclose, high temperature afterburner that consumes
and chemically treats pollutants in the engine exhaust.
• An afterburner used to reduce the amount of exhaust
pollutants entering the atmosphere
One or more catalytic converter can be located in the
exhaust system
Types of catalytic converter
• Mini catalytic converter
• Two-way catalytic converter
• Three-way catalytic converter
• Dual bed catalytic converter

15. Catalytic converter

16. Resonator
• A resonator is a hollow chamber in the exhaust tract
that creates a frequency of pulses that reverse the
pulses coming down the exhaust pipe
• It works in conjunction with the muffler to quiet the
exhaustion being emitted from the car
Service
Check for rattling to indicate loose pieces or debris
build-up

17. Resonators

18. Heat Shield
• Metal plates that prevent exhaust heat from
transferring to the fuel lines, floor, transmission and
engine
• Located in areas where the exhaust system
components are close to the vehicle’s body or near
the ground
• The shields reduce the amount of heat transferred
into the body and protect items under the vehicle
• Heat shields should be flat and not bent

19. Heat Shield

20. Exhaust system service
• Exhaust systems rust because of acids and moisture
– Exhaust gaskets suffer a good deal of abuse
– Header pipes collapse resulting in a restriction
• Tools used for exhaust work
– Chain-type pipe and roller-type exhaust cutters
– Pipe expander
– Deep sockets
– Chisel cutter
– Oxyacetylene torch

21. Damaged exhaust pipe

22. Turbocharger
• Small radial fan pump driven by the energy of the
exhaust flow
– Helps a smaller engine provide more power
• Components and characteristics
– Centrifugal pump
– Diffuser and volute
– Size must match compressor
– Boost pressure: amount of air density provided
– Turbo lag: time required to bring the turbo up to a
functioning speed

23. Turbocharger(Cont)
• Supercharged systems
– Use different ways to prevent excess pressure from
accumulating
• Waste gate
– Prevents overpowering
– Internal and external
– Amount of boost can be changed
• Spring or boost controllers
• Valves
– Blow-off and compressor by-pass

24. Turbocharger(Cont)
• Variable geometry turbochargers
– Vary turbocharger geometry
• After cooler/intercooler
– Cooled by either air or water
• Turbocharger thrust/boost differential
– Occurs when pressure is higher in either the turbine
or the compressor
• Turbocharger parts
– Bearings, turbine shaft, compressor, turbine wheels,
and housings

26. Function of Turbocharger
A turbocharger 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. This improvement
over a naturally aspirated engine’s power output is
due to the fact that the compressor can force more
air and proportionately more fuel into the
combustion chamber than atmospheric pressure
alone.

27. Functions of turbocharger parts
• 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 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.
Turbochargers start producing boost only when a certain
amount of kinetic energy is present in the exhaust gases.
Without adequate exhaust gas flow to spin the turbine blades,
the turbocharger cannot produce the necessary force needed
to compress the air going into the engine.

28. Functions of turbocharger parts(cont.)
• Turbine
The turbocharger turbine, which consists of a turbine
wheel and a turbine housing, converts the engine
exhaust gas into mechanical energy to drive the
compressor. The gas, which is restricted by the
turbine’s flow cross-sectional area, results in a
pressure and temperature drop between the inlet
and outlet. This pressure drop is converted by the
turbine into kinetic energy to drive the turbine
wheel.

29. Functions of turbocharger parts(cont.)
• Compressor
Turbocharger compressors are generally centrifugal
compressors consisting of three essential component:
compressor wheel, diffuser, and housing. With the
rotational speed of the wheel, air is drawn in axially,
accelerated to high velocity and then expelled in a radial
direction. The diffuser slows down the high-velocity air,
largely without losses, so that both pressure and
temperature rise. The diffuser is formed by the
compressor backplate and a part of the volute housing,
which in its turbine collects the air and slows it down
further before it reaches the compressor exit.

30. Functions of turbocharger parts(cont.)
• Center Housing/ Hub
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. For instance,
in automotive applications the CHRA typically uses a thrust
bearing of ball bearing lubricated by a constant supply of
pressurized engine oil. The CHRA may also be considered
water-cooled by having and entry and exit point for engine
coolant. Water-cooled models use engine coolant to keep
lubricating oil cooler, avoiding possible oil coking from the
extreme heat in the turbine. The development of air-foil
bearing removed the risk.

31. Turbocharger (Troubleshooting)
• Turbocharger balance
– Turbo spin in excess of 100,000 rpm and are
balanced to run in excess of 150,000 rpm
• Turbocharger replacement
– Not usually attempted in repair shops
• Turbocharger troubleshooting
– Common failures: blockages, leaks, and foreign
object damage

32. Turbocharger(Troubleshooting)
• Diagnosing damage to a turbo
– Turbine damage
• Broken piston rings, valves, or pistons
– Compressor damage
• Results from objects entering the intake
• Thrust bearing failure
– Not common