IC engines, Classification , Application

1. Chapter I
Introduction to IC Engines
By
Dr. S. Murali
Professor & Head
Dept. of Mechanical Engineering

2. Thermodynamics
•Branch of science which deals with H t
B
h f i
hi h d l
ith Heat
and Work
•Basic principles
B i
i i l
–Zeroeth law
• Basis for Temperature measurement
–First Law
• Conversion of Energies
–Second Law
• Rectifies flaws in First Law
• Basic theories for Heat Engines development

3. Engine & Heat Engine
Engine : D i used t convert one form
E i
Device
d to
t
f
of energy another form of energy.
A heat engine diverts some heat as it flows
naturally from hot to cold and converts
that heat into useful work
Heat Engine:
(i) Internal combustion engine
(ii) External combustion engine

4. Internal Combustion engine

5. External Combustion engine

6. IC Engine(Reciprocating)
Gudgeon pin
Cylinder
Cooling Jacket
Crank Shaft
Crank Web
Crankcase

7. Reciprocating IC Engine(Parts)
• Pi t
Piston- cylindrical piece of metal th t moves
li d i l i
f
t l that
up and down the cylinder.
• Piston rings rings provide a sliding seal
ringsbetween the piston and cylinder.
• Rings serve two purposes:
–prevent fuel/air from leaking into the
sump
–prevent oil from entering the combustion
chamber0
•Combustion chamber- area where
combustion and compression takes place.

8. Reciprocating IC Engine(Parts)
•Connecting rod- connects th piston t the
C
ti
d
t the i t
to th
crankshaft.
•Crankshaft- th crankshaft turns the up
C
k h ft the
k h ft t
th
and down motion of the piston into circular
motion
•Sump- (oil pan) contains and collects oil
for lubrication

9. IC Engine Terminology
Clearance
Top dead center
(TDC)
Stoke (L)
Bottom dead center
(BDC)
Cylinder B
C li d Bore
(D)
π
Displacement or Stroke Volume (Vs ) = A × L = D 2 L
4
Cylinder Volume (V )
C li d V l
= dispacement volume + clearance volume = VS + VC
VS
V VC + VS
Compression Ratio(r ) =
p
=
= 1+
VC
VC
VC

10. CLASSIFICATION OF IC ENGINES
1.
1 Application
2. Basic Engine Design
3. Operating Cycle
4. Working Cycle
5. Valve/Port Design and Location
6. Fuel
7. Mixture Preparation
8. Ignition
8 I iti
9. Stratification of Charge
10.
10 Combustion Chamber Design
11. Method of Load Control
12. Cooling
g

11. CLASSIFICATION OF IC ENGINES
Application
1. Automotive:
()
(i) Car
(ii) Truck/Bus
(iii) Off-highway
2.
2 Locomotive
3. Light Aircraft
4. Marine: (i) Outboard
(ii) Inboard
(iii) Ship
5. Power Generation:
(i)
(ii)
Portable (Domestic)
Fixed (Peak Power)

12. Application

13. CLASSIFICATION OF IC ENGINES
6.
6 Agricultural:
(i)
(ii)
7. Earthmoving:
(i)
(ii)
(iii)
8. Home U
8 H
Use:
(i)
(ii)
(iii)
9. Others
Tractors
Pump sets
Dumpers
Tippers
Mining Equipment
Lawnmowers
Snow blowers
Tools

14. Application

15. CLASSIFICATION OF IC ENGINES
Basic Engine Design
Design:
1. Reciprocating
(a) Single Cylinder
(b) Multi-cylinder
(I)
In-line
(ii)
V
(iii)
Radial
(iv) Opposed Cylinder
(v)
Opposed Piston
2. R t
2 Rotary: (a) Single Rotor
( ) Si l R t
(b) Multi-rotor

16. Basic Engine Design
Vertical
Horizontal
Slanted

17. Basic Engine Design
In-line
V
Horizontally opposed

18. Basic Engine Design

19. CLASSIFICATION OF IC ENGINES
•
•
•
•
•
Operating Cycle
O
ti
C l
Otto (For the Conventional SI Engine)
Atkinson (For Complete Expansion SI
Engine)
Miller (For Early
Mill (F E l or L t I l t Valve
Late Inlet V l
Closing type SI Engine)
Diesel (For the Ideal Di
Di
l (F th Id l Diesel Engine)
lE i )
Dual (For the Actual Diesel Engine)

20. CLASSIFICATION OF IC ENGINES
Working C cle (St okes)
Wo king Cycle (Strokes)
1. Four Stroke Cycle:
(a) Naturally Aspirated
(b)Supercharged/Turbocharged
2.
2 Two Stroke Cycle:
(a) Crankcase Scavenged
(b) Uniflow Scavenged
(i) Inlet valve/Exhaust Port
(ii) Inlet Port/Exhaust Valve
(iii) Inlet and Exhaust Valve
ay b
a u a y sp a d
May be Naturally Aspirated
Turbocharged

21. CLASSIFICATION OF IC ENGINES
1.
2.
2
3.
4.
4
1.
1
2.
3.
4.
Valve/Port
Val e/Po t Design
Poppet Valve
Rotary Valve
Reed Valve
Piston Controlled Porting
Valve Location
The T-head
T head
The L-head
The F-head
F head
The I-head: (i) Over head Valve (OHV)
(ii) Over head Cam (OHC)
( ) O
ad Ca (O C)

22. CLASSIFICATION OF IC ENGINES
Fuel
1.Conventional:
(a) Crude oil derived
(i) Petrol
(ii) Diesel
(b) Other sources
(i) Coal
(ii) Wood (i l d bi
W d (includes bio-mass)
)
(iii)Tar Sands
(iv)Shale

23. CLASSIFICATION OF IC ENGINES
Fuel
2. Alternate:
(a) Petroleum derived
(i) CNG(Compressed Natural Gas)
(ii) LPG(Liquid Petroleum Gas)
(b) Bio-mass Derived
(i) Alcohols (methyl and ethyl)
(ii) Vegetable oils
V
t bl
il
(iii) Producer gas and biogas
(iv) Hydrogen
3. Blending
4. Dual fueling
g

24. CLASSIFICATION OF IC ENGINES
Mixture P
Mi t
Preparation
ti
1. Carburetion
2. Fuel Injection
(i) Diesel
(ii) Gasoline
(a) Manifold
(b) Port
(c) Cylinder

25. CLASSIFICATION OF IC ENGINES
Ignition
I iti
1. Spark Ignition
(a)
Conventional
(i) Battery
(ii) Magneto
(b)
Other methods
2. Compression Ignition

26. CLASSIFICATION OF IC ENGINES
Charge Stratification
Ch
St tifi ti
1. Homogeneous Charge (Also Pre-mixed
charge)
2. Stratified Ch
2 St tifi d Charge
(i) With carburetion
(ii) With fuel injection

27. CLASSIFICATION OF IC ENGINES
1.
2.
Combustion Chambe
Comb stion Chamber Design
Open Chamber
(i) Disc type
(ii) Wedge
(iii) Hemispherical
(iv) Bowl-in-piston
(v) Other design
Divided Chamber
(For CI)
(For SI)
(i) Swirl chamber (i) CVCC
(ii) Pre-chamber
( )
a b
(ii) Other designs
( )O
d sg s

28. CLASSIFICATION OF IC ENGINES
Method f L d Control
M th d of Load C t l
1. Throttling: (To keep mixture strength
constant) Al called Ch
t t) Also ll d Charge Control
C t l
Used in the Carbureted S.I. Engine
2. Fuel C t l (To
2 F l Control (T vary th mixture
the i t
strength according to load)
Used in th C I E i
U d i the C.I. Engine
3. Combination
Used in the F l i j t d S.I. E i
U d i th Fuel-injected S I Engine.

29. CLASSIFICATION OF IC ENGINES
Cooling
1.
1 Direct Air cooling
Air-cooling
2.
2 Indirect Air-cooling (Liquid Cooling)
3.
3 Low Heat Rejection (Semi-adiabatic)
(Semi adiabatic)
engine.

30. CLASSIFICATION OF IC ENGINES
Cooling
1.
1 Direct Air cooling
Air-cooling
2.
2 Indirect Air-cooling (Liquid Cooling)
3.
3 Low Heat Rejection (Semi-adiabatic)
(Semi adiabatic)
engine.

31. Cooling

32. Working of Four Stroke SI Engine
Sequential operations
S
i l
i
•Induction Stroke: fill cylinder with air fuel
mixture
•Compression Stroke: squeeze mixture
•Power Stroke: burn and extract work
•Exhaust Stroke: empty cylinder of exhaust

33. Induction Stroke(1→2)
• Piston moves from TDC to BDC
• Intake valve - open
• Exhaust valve- closed
• Engine pulls piston out of cylinder
• Low pressure inside cylinder
• air fuel mixture (carburretted 14 to 15
on weight basis) enters into cylinder
• Flywheel angle of rotation 0-180
• Engine does work on the gases during
this stroke

34. Compression Stroke(2→3)
• Piston moves from BDC to TDC
• Intake valve – closed
• Exhaust valve- closed
• Engine pushes piston into cylinder
• Mixture is compressed to high
pressure and temperature
• Flywheel angle of rotation 180-360
• Engine does work on the gases during
this stroke

35. Power Stroke(3→4)
• Piston moves from TDC-BDC
• Intake valve - closed
• Exhaust valve - closed
• Mixture burns to form hot gases
• Gases push piston out of cylinder
• Gases expand to lower pressure and
temperature
• Flywheel angle of rotation 360-540
• Gases do work on engine during this
stroke

36. Exhaust Stroke
• Piston moving up
•
Intake valve closed
•
Exhaust valve open
• Engine pushes piston into cylinder
• High pressure inside cylinder
• Pressure pushes burned gases out of
cylinder
• Flywheel angle of rotation 540-720
• Engine does work on the gases during
this stroke

37. SI Engine Animation & Ideal PV-Diagram
3
1
2
3
4
1
intake
isentropic compression
isochoric h ti
i
h i heating
isentropic expansion
0 exhaust
ignition
P
0
1
2
3
4
2
Patm
0
1
exhau
ust
4
Intake / exhaust
V2
V1
V

38. Working of 4 stroke CI Engine
• operation i quite similar t SI engine
ti
is
it i il to
i
–However
• F l Injectors are used for
Fuel I j t
df
atomized fuel injection
• Fresh air is entered during induction stroke
g
• Heterogeneous mixture is burned because of
self ignition of the fuel

39. Working of 4 stroke CI Engine
0 → 1induction
1 → 2 isentropic compression
2 → 3const. vloume heat addition
3 → 4 isentropic exp ansion
4 → 1 → 0 const. pressure
heat j ti
h t rejection
0
Intake / exhaust

40. Salient features of 4 stroke engine
•Provided with valves
P
id d ith
l
•It requires four strokes
•Two revolution of crank shaft
•One power stroke for every four strokes
•Flywheel stores energy during power
stroke and supplies part of energy for idle
strokes

41. SI engine Vs CI engine
Description
Basic Cycle
Fuel
Introduction f
I t d ti of
Fuel
SI
CI
Otto cycle or constant
Diesel cycle or
volume heat addition cycle constant pressure heat
addition
Gasoline, a highly volatile Diesel, a non volatile
,
g y
,
fuel, high self ignition
fuel, low self ignition
temperature
temperature
A mixture of fuel and air is F l i injected just at
i t
f f l d i i Fuel is i j t d j t t
introduced during suction the end of compression
stroke(Induction Stroke)
stroke
Load control
Quantity governed
Quality governed
Fuel Ignition
g
Requires Spark plug
q
p
p g
Self ignition
g

42. SI engine Vs CI engine(contd)
Description
Compression
ratio
Thermal
efficiency
y
Weight
SI
CI
6-10
16-20
Low efficiency(Lower
compression ratio)
p
)
Higher
efficiency(higher
y( g
compression ratio)
Heavier(higher peak
pressure)
)
Lighter in weight(low
peak pressure)
k
)

43. Click to edit Master title style
THANK YOU
Contact: smualichinna@gmail.com