different types of engines and their working is discussed

1. NATIONAL INSTITUTE OFNATIONAL INSTITUTE OF
TECHNICAL TEACHERSTECHNICAL TEACHERS
TRAINING AND RESEARCHTRAINING AND RESEARCH
CHANDIGARHCHANDIGARH
112/20/14
Prof. (Dr.) MP Poonia
Director, NITTTR
Chandigarh (India)

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3. Diesel Emission
Reductions

4. Fuel technology
Combustion
technology
Aftertreatment
technology
Fuel system
technology
Better understanding
of combustion
Alternate Fuels
(Biodiesel)Low
sulfur
PM
trap
Rate control
High pressure
Multi-injection
EGR technology
Others
Control
technology
Technology Pathway

5. Emission norms for
passenger cars ( Petrol)
5
Norms CO( g/km) HC+ NOx)(g/km)
1991Norms 14.3-27.1 2.0(Only HC)
1996 Norms 8.68-12.40 3.00-4.36
1998Norms 4.34-6.20 1.50-2.18
stage
2000 norms
2.72 0.97
Bharat stage-II 2.2 0.5
Bharat Stage-III 2.3 0.35(combined)
Bharat Stage-IV 1.0 0.18(combined)

6. Emission norms for
Heavy diesel vehicles:
6
Norms CO
(g/kwhr)
HC
(g/kwhr)
Nox
(g/kwhr)
PM
(g/kwhr)
1991 Norms 14 3.5 18 -
1996 Norms 11.2 2.4 14.4 -
stage 2000 Norms 4.5 1.1 8.0 0.36
Bharat stage-II 4.0 1.1 7.0 0.15
Bharat Stage-III 2.1 1.6 5.0 0.10
Bharat Stage-IV 1.5 0.96 3.5 0.02

7. Emission sources in a
gasoline fuelled car
Ref : http://nptel.iitm.ac.in/courses/112104033/2

8. Emission Sources in a Diesel
Engine Powered Bus
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• Volumetric efficiency (ηv) = (mass of air actually drawn into
cylinder) / (mass of air that ideally could be drawn into cylinder)
where ρair is at ambient = Pambient/RTambient and R - 287 J/kgK for air
• Volumetric efficiency indicates how well the engine “breathes” -
what lowers ηv below 100%?
– Pressure drops in intake system (e.g. throttling) & intake
valves
– Temperature rise due to heating of air
– Volume occupied by fuel
– Non-ideal valve timing
– “Choking” (air flow reaching speed of sound) in part of intake
system having smallest area
Volumetric Efficiency
nNVdair
v
/
(measured)mair
ρ
η

≡

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13. Turbochargers &
Superchargers
• Superchargers:
mechanically driven from
engine crankshaft
• Turbochargers:
driven by waste exhaust
gases increased air mass
improves the engine's
thermal efficiency (fuel
economy) and emissions
performance,

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• Engine performance is specified in both in
terms of power and engine torque - which is
more important?
–Wheel torque = engine torque x gear ratio
tells you whether you can climb the hill
Power and Torque

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–Power tells you how fast you can climb the hill
–Torque can be increased by transmission (e.g.
2:1 gear ratio ideally multiplies torque by 2)
Power can’t be increased by transmission; in
fact because of friction and other losses, power
will decrease in transmission
–Power tells how fast you can accelerate or how
fast you can climb a hill, but power to torque
ratio ~ N tells you what gear ratios you’ll need
to do the job

23. There is a maximum in the brake power
versus engine speed called the rated
brake power.
At higher speeds brake power decreases
as
friction power becomes significant
compared
to the indicated power
There is a maximum in the torque versus
speed called maximum brake torque
(MBT).
Brake torque drops off:
• at lower speeds do to heat losses
• at higher speeds it becomes more
difficult to ingest a full charge of air.
Max brake torque
1 kW = 1.341 hp
Rated brake power
Power and Torque versus
Engine Speed

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Mathematically different from
the British unit
1 Power PS = 0.986 Bhp
Pferde Stärke = Horse
Strength (German)
Power
(PS@rpm)
67@5500 65@6200
Torque
(Nm@rpm)
99@2800 84@3500

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Convert from these to
watts (W)
multiply by
erg's per second (erg/s) 0.000 000 1
horsepower (electric) 746
horsepower (hp)
(metric,DIN,PS)
735.4988
horsepower (hp)(U.K.) 745.7
kilowatt (kW) 1000

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Engine
Engine Type/Model 1.4L SOHC Petrol
Displacement cc 1405
Power (PS@rpm) 60PS @4500rpm
Torque (Nm@rpm) 105Nm @2500rpm
Valve Mechanism SOHC
Bore (mm) 75
Stroke (mm) 95
Compression Ratio 9:1
No of Cylinders (cylinder) 4
Cylinder Configuration Inline
Valves per Cylinder (valve) 2
Fuel Type Petrol
Fuel System Carburettor mechanical fuel pump

28. Engine Torque and Power
Torque is measured using a dynamometer.
Load cell
Force FStator
Rotor
b
N
The torque exerted by the engine is: T = F b with units: J
The power Wdot delivered by the engine turning at a speed N and
absorbed by the dynamometer is:
Wdot = ω T = (2π N) T w/units: (rad/rev)(rev/s)(J) = Watt
Note: ω is the shaft angular velocity with units: rad/s

29. Indicated Work
Given the cylinder pressure data over the operating cycle of the engine
one can calculate the work done by the gas on the piston.
The indicated work per cycle is ∫= PdVWi
Compression
W<0
Power
W>0
Intake
W>0
Exhaust
W<0
WA > 0
WB < 0

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Indicated Mean Effective Pressure (Pim):
p-V diagram for an ideal four-stroke cycle
engine

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35. I.C. ENGINE TESTING
Measurement of Air
Supply of an I.C.
Engine:
Measurement
of Air
by Air Box
Method.
5

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