Pollution Free Engine; Stirling Engine

1. A
SEMINAR REPORT
ON
POLUTION FREE ENGINE
SUBMITTED TO
IN PARTIAL FULFILMENT OF THE REQUIREMENT FOR THE
AWARD OF THE DEGREE OF
BACHELOR OF TECHNOLOGY
IN
MECHANICAL ENGINEERING
SUBMITTED BY
NILESH KUMAR
(1805240907)
UNDER THE GUIDANCE OF
Er. PRAYAS RAI
MED, IET, LUCKNOW
Mechanical Engineering Department,
Institute of Engineering & Technology,
Lucknow-226021, U.P.
2019-20

2. Certificate
Certified that this B.Tech. Seminar/Project Report titled “Pollution Free Engine” by
“NILESH KUMAR” is approved by me for submission. Certified further that, to the best of my
knowledge, the report represents work carried out by the student.
DATE:-
Er. PRAYAS RAI Dr. Arun K. Tiwari
Guide & Asst. Professor Head of the Department
Department of Mechanical
Engineering,
Department of Mechanical
Engineering
IET, Lucknow-226021 IET, Lucknow-226021
Mechanical Engineering Department,
Institute of Engineering & Technology,
Lucknow-226021, UP
2019-20

3. Acknowledgements
I would like to express my sincere gratitude, regards and thanks to my respected guide
Er. Prayas Rai, Assistant Professor, Department of Mechanical Engineering, IET, Lucknow,
for providing valuable insights, setting up clear and well-defined goals during the course of
this work, who is apart from being my guide has been a great mentor and motivator. It is one
of my achievements to work under his guidance. He is constant source of encouragement and
momentum that any intricacy becomes simple. I gained a lot of invaluable guidance and
prompt suggestions from him during my entire report work. I remained indebted of him
forever and I take pride to work under his guidance.
At last, the utmost sense of gratitude is felt towards my parents and family. I humbly
thanks to God for every success in my life.
NILESH KUMAR

4. 1
SEMINAR REPORT
2019-20
MECHANICAL ENGINEERING DEPARTMENT
Abstract
The quest of human beings to develop engines with high power, high torque, less vibration and most
essentially with no pollution is on since the discovery and development of engine. Stirling engine is
just one step forward towards the creation of a noise free and pollution less engine.
The Stirling engine is the engine, which uses a fixed amount of gas sealed inside a cylinder. The
expansion and contraction of the gas, using heat from external source, creates the useful work. The
main advantage of this engine is its capability to use any type of fuel and the emission of no exhaust
gases.
Due to this pollution free and use of any type of fuel characteristics the Stirling engine shows a greater
potential over any other type of engine existing today. To consolidate this claim an effort has been made
to develop a working model of Stirling

5. 2
SEMINAR REPORT
2019-20
MECHANICAL ENGINEERING DEPARTMENT
CONTENTS
Abstract....................................................................................01
Contents ..................................................................................02
List of Figures ..........................................................................03
1. INTRODUCTION .....................................................................04
2. HISTORICAL JOURNEY OF THE ENGINE.............................05
3. STIRLING ENGINE..................................................................06
4. TYPES OF STIRLING ENGINE ...............................................07
4.1 TWO PISTON TYPE STIRLING ENGINE...........................07
4.2 DISPLACER TYPE STIRLING ENGINE .............................08
5. PARTS OF STIRLING ENGINE ...............................................09
6. STIRLING CYCLE ...................................................................10
7. MERITS AND DEMERITS OF STIRLING CYCLE....................12
7.1 MERITS..............................................................................12
7.2 DEMERITS.........................................................................12
8. RECENT APPLICATIONS OF STIRLING CYCLE ...................13
9. SUMMARY...............................................................................14
10. REFERENCES ........................................................................15

6. 3
SEMINAR REPORT
2019-20
MECHANICAL ENGINEERING DEPARTMENT
LIST OF FIGURES
Figure3.1:SIMPLE STIRLING ENGINE .............................................................. 06
Figure4.1: Two Piston Type Stirling Engine ........................................................ 07
Figure4.2: Displacer Type Stirling Engine........................................................... 08
Figure5.1 Stirling Engine and Its Components...................................................... 09
Figure6.1:P-V & T-S diagrams of Stirling Cycle................................................. 10
Figure8.1:Multiple Cylinder Alpha Stirling Engine ............................................... 13

7. 4
SEMINAR REPORT
2019-20
MECHANICAL ENGINEERING DEPARTMENT
CHAPTER-1
INTRODUCTION
All of us including the lamest of laymen would have at one time or another experienced
problems with our vehicles engine and most of the time after moaning and cursing finally
in line with the universe and accepting our doom we would have coughed up the cash for
repairs and parts and insistently taken old parts home, disregarding the fact that no
descent human would have wanted them and during this exercise in existence it is
doubtful that anybody would have chance to miss seeing a piston or two, this ubiquitous
creatures that scurry up and down in an enclosed cylindrical space, getting their crowns
slammed regularly and unceremoniously…eventually to be thrown aside and replaced by
a marginally wider chap. Doubtful that any of us would be able to imagine modern travel
without an internal combustion cycle. Hell if we ask our mechanic if he has ever seen a
vehicle without any exhaust then he is probably going to refer to you to the nearest
shrink.
So an engine without any exhaust gas is a mirage or it can be a reality? The answer
for this is definitely yes. We can have an engine without any exhaust gas and that is what
a Stirling engine is.

8. 5
SEMINAR REPORT
2019-20
MECHANICAL ENGINEERING DEPARTMENT
CHPTER-2
HISTORICAL JOURNEY OF THE ENGINE
The Stirling engine is a heat engine that is vastly different from the internal-combustion
engine in your car. It was invented by Robert Stirling in 1816 as a pumping engine in
mines. It used air at low pressure as its ‘working fluid’.It was inefficient and bulky and was
replaced due to lack of thermodynamic knowledge 150 years ago. Modern technology
made possible the revival of the Stirling engine by Philips in 1938. The practical Stirling
engines in small numbers are being produced since 1965.
The Stirling engine has the potential to be much more efficient than a gasoline or diesel
engine. But today, Stirling engines are used only in some very specialized applications,
like in submarines or auxiliary power generators for yachts, where quiet operation is
important. Although there hasn't been a successful mass-market application for the Stirling
engine, some very high power inventos are working on it.

9. 6
SEMINAR REPORT
2019-20
MECHANICAL ENGINEERING DEPARTMENT
CHAPTER-3
STIRLING ENGINE
The Stirling engine is a heat engine that is vastly different from an internal combustion
engine. It is an external combustion engine. Stirling engines have two pistons that create
a 90-degree phase angle and two different temperature spaces. The working gas in the
engine is perfectly sealed, and doesn't go in and out to the atmosphere. The Stirling
engine uses a Stirling cycle, which is unlike the cycles used in normal internal
combustion engines.
FIG-3.1 SIMPLE STIRLING ENGINE
(Ref.; https://www.a3bs.com/imagelibrary/U49327/U49327_01_Simple-Stirling-Engine.jpg )
• The gas used inside Stirling engine never leaves the engine. There are no exhaust
valves that vent high-pressure gases as in petrol or diesel engine, and there are no
explosions taking place.
• The Stirling cycle uses external heat source, which could be anything from
gasoline to solar energy to heat produced by decaying plants. No combustion
takes place inside cylinder of the engine.

10. 7
SEMINAR REPORT
2019-20
MECHANICAL ENGINEERING DEPARTMENT
CHAPTER-4
TYPES OF STIRLING ENGINE
Stirling engines can be classified as:
1. Two pistons type Stirling engine
2. Displacer type Stirling engine
4.1 Two Piston Type Stirling Engine:
The two-piston type Stirling engine uses two power pistons as shown in fig-4.1. Out of the two
pistons one is hot piston, which is used in hot chamber, and the other one is a cold piston used in
cold chamber. The space above a hot piston is always heated by a heat source. The space above a
cold piston is cooled always by cold air. In this engine, the heated cylinder is heated by an
external flame. The cooled cylinder is air-cooled, and has fins on it to aid in the cooling process.
A rod stemming from each piston is connected to a small disc, which is in turn connected to a
larger flywheel. This keeps the pistons moving when no power is being generated by the engine.
FIG-4.1 Two Piston Type Stirling Engine
(Ref.: https://www.stirlingengine.com/wp-content/uploads/2018/04/two-piston.gif )

11. 8
SEMINAR REPORT
2019-20
MECHANICAL ENGINEERING DEPARTMENT
4.2 Displacer Type Stirling Engine:
The displacer type Stirling engine uses a power piston and a displacer. That means instead of
having two pistons, a displacer-type engine has one piston and a displacer as shown in Fig-4.2;
1. The power piston - This is the smaller piston at the top of the engine. It is a tightly-sealed
piston that moves up as the gas inside the engine expands.
2. The displacer - This is the large piston in the drawing. This piston is very loose in its cylinder,
so air can move easily between the heated and cooled sections of the engine as the piston
moves up and down.
The displacer serves to control when the gas chamber is heated and when it is cooled. The
space below a displacer piston is always heated by a heat source. The space above the
displacer piston is cooled always by cold air. The displacer piston displaces hot air and cold
air.
In order to run, the engine above requires a temperature difference between the top and
the bottom of the large cylinder. In this case, the difference between the temperature of
your hand and the air around it is enough to run the engine.
FIG-4.2 Displacer Type Stirling Engine
(Ref.: http://people.westminstercollege.edu/faculty/ccline/courses/resources/wp/Stirling/tech2.gif )

12. 9
SEMINAR REPORT
2019-20
MECHANICAL ENGINEERING DEPARTMENT
CHAPTER-5
PARTS OF A STIRLING ENGINE
5.1 Main chamber: It is the chamber where a fixed amount of gas is sealed initially.
Inside this chamber only expansion and compression of gas takes place.
5.2 Output Shaft: It is horizontal and mounted several inches above the main
chamber. The end of shaft centered over the main chamber has a crank and
connecting rod, which drives the displacer.
5.3 Displacer: This is the large piston in the drawing. This piston is very loose in its
cylinder, so air can move easily between the heated and cooled sections of the
engine as the piston moves up and down.
5.4 Power piston: This is the smaller piston at the top of the engine. It is a tightly
sealed piston that moves up as the gas inside the engine expands.
5.5 Crankshaft: The crankshaft is made up of steel, which passes through the bearing
and receives the crank disc .the crank disc forms mount for flywheel.
5.6 Regenerator: The regenerator is constructed of material that readily conducts heat
and has a high surface area. When hot gas is transferred to the cool cylinder, it is
first driven through the regenerator, where a portion of the heat is deposited. When
the cool gas is transferred back, this heat is reclaimed; thus the regenerator "pre
heats" and "pre cools" the working gas, dramatically improving efficiency.
FIG-5.1 Stirling Engine and its Components
(Ref.; https://www.mdpi.com/energies/energies-10-01609/article_deploy/html/images/energies-10-01609-g001-550.jpg )

13. 10
SEMINAR REPORT
2019-20
MECHANICAL ENGINEERING DEPARTMENT
CHAPTER-6
STIRLING CYCLE
The key principle of Stirling engine is that a fixed amount of gas is sealed inside the
engine. The Stirling cycle involves a series of events that change the pressure of gas
inside the engine, causing it to work.
Stirling engine uses two cylinders, one cylinder is heated by an external heat source and
the other is cooled by an external cooling source. A linkage that determines how they
will move in relation one another connects the gas chambers of the two cylinders to each
other mechanically.
Thermodynamically, the ideal Stirling cycle consists of an isothermal compression,
constant volume heat addition, isothermal expansion, and constant volume heat
rejection.
The P-V and T-S diagrams of an ideal Stirling cycle is shown in fig-6.1, include the
following four thermodynamic processes;
FIG-6.1 P-V & T-S diagrams of Stirling Cycle
(Ref.; https://ars.els-cdn.com/content/image/3-s2.0-B9780128015759000019-f01-06-
9780128015759.jpg?_ )
i. 1-2: Reversible isothermal compression;- In which volume of the gas decreases and
the pressure increases as it gives up heat to the sink.

14. 11
SEMINAR REPORT
2019-20
MECHANICAL ENGINEERING DEPARTMENT
ii. 2-3: Reversible isochoric heat addition;- In which the volume of the gas remains
constant as it passes back through the regenerator and regains some of its previous heat.
iii. 3-4: Reversible isothermal expansion;- In which the gas absorbs energy from the
source, its volume increases and its pressure decreases, while the temperature remains
constant.
iv. 4-1: Reversible isochoric heat rejection;- in which the volume of the gas remains
constant as it transfers through the regenerator and cools.
The working medium in a Stirling cycle is a gaseous matter, such as air, helium,
hydrogen, etc., instead of water and steam. Like the Carnot cycle all the processes in an
ideal Stirling cycle are reversible in nature, hence when the gas is heated the engine
produces work or power and when work is supplied to the cycle it works as the
refrigerator or the heat pump. When the processes in the Stirling cycle are reversed they
act as cryogenerator and the cycle is used in the field of cryogenics to produce extremely
low temperatures or to liquefy gases like helium and hydrogen.

15. 12
SEMINAR REPORT
2019-20
MECHANICAL ENGINEERING DEPARTMENT
CHAPTER-7
MERITS AND DEMERITS OF STIRLING ENGINE
7.1 MERITS:
1. The biggest advantage of Stirling engines is that they're much more efficient than
steam engines.
2. There is no exhaust of gases as in case of normal piston engines.
3. These engines are quieter in operation.
4. Gas inside the engine never leaves the engine.
5. The external heat source could be anything-even heat from our hand.
6. No combustion takes place inside cylinder of engine. Hence there is no
explosion.
7.2 DEMERITS:
On the downside, there is some demerits of Stirling engine;
1. Stirling engines don't start instantly i.e. it takes time for the all-important heat
exchanger to warm up and the flywheel to run up to speed.
2. They don't work so well in stop-start operation (unlike internal combustion
engines).
3. They also need large radiators that can expel waste heat, which makes them
unsuitable for some applications.

16. 13
SEMINAR REPORT
2019-20
MECHANICAL ENGINEERING DEPARTMENT
CHAPTER-8
RECENT APPLICATIONS OF STIRLING CYCLE
Multiple Cylinder Alpha Stirlin Engine:-
It is also know as The Siemens Stirling Engine. The Alpha engine can be compacted into a small
multiple cylinder configuration, enabling very high power output. A schematic diagram of the
"Siemens" configuration is shown in fig-8.1. The Siemens configuration does not use two separate
pistons, but rather uses the front and back side of one piston called a double-acting piston. With a
double-acting piston, the expansion space of the front side of one piston is connected to the
compression space of the back side of the adjacent piston through the in line heater, regenerator, and
cooler. The Siemens configuration involves four cylinders each with a double-acting piston 90
degrees out of phase with the next cylinder. The Siemens configuration greatly improves the engine
efficiency over the original alpha arrangement. These engines have the power piston connected to the
crankshaft by a second connecting rod, which is itself in another small cylinder to eliminate the lateral
forces from the crankshaft from putting pressure on the engine cylinder walls. This arrangement is
called a "crosshead". A seal is used between the cross-head and piston to separate the high pressure
area from the low pressure zone. This allows the crosshead surfaces to stay lubricated in the low
pressure area while preventing fouling in the high pressure engine system.
FIG-8.1 Multiple Cylinder Alpha Stirling Engine
(Ref.; https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcTQ-RRLkGmNoxbvkKohD3rbINNGm3dfnhQQU3-
BX3YEoNFlYGpc&s )

17. 14
SEMINAR REPORT
2019-20
MECHANICAL ENGINEERING DEPARTMENT
CHAPTER-9
SUMMERY
The Stirling engine, types, parts; working cycle, advantages along with recent
applications has been empounded in this paper. The Stirling engine is the engine, which
uses the gas sealed inside the cylinder. The expansion and contraction of the gas, using
heat from external source, creates the useful work. This engine can work on any type of
fuel whether it is conventional or non-conventional fuel. And the basic advantage of this
engine is that the amount of gas inside the chamber remains fixed that is there is no
exhaust and hence this engine is pollution less.
Due to this pollution free and use of any type of fuel characteristics the Stirling engine
has greater potential over any other type of engine existing today. Hence this engine is
highly preferred in automobile sector finding its application in submarines to hybrid cars.
Due to the above specified advantages the Striling engine is giving a cutting edge to all
other engine existing today and is viewed as an answer to the existing energy crisis.

18. 15
SEMINAR REPORT
2019-20
MECHANICAL ENGINEERING DEPARTMENT
REFERENCES:
[1]. Dhanpat Rai Publications, Internal Combustion Engine, 23rd
Reprint
Ed.;2011 , Chap. 1, pp 11-13, M.L. MATHUR, New Delhi, 1976.
[2].“Dipak K. Sarkar, in “Thermal Power Plant”, 2015”
(https://www.sciencedirect.com/topics/engineering/stirling-cycle )
[3].“Stirling engine by Chris Woodford”, December 22, 2018.
(https://www.explainthatstuff.com/how-stirling-engines-work.html)
[4]. “How Stirling Engines Work”
(https://auto.howstuffworks.com/stirling-engine1.htm)
[5]. “Stirling engine configurations”
(https://www.ohio.edu/mechanical/stirling/engines/engines.html)
[6]. (http://solarcellcentral.com/stirling_page.html)
[7]. (https://www.mdpi.com/journal/energies)
[8]. (https://www.sciencedirect.com/)