Internal Combustion Engines

Lecture-30
Prepared under
QIP-CD Cell Project
Internal Combustion Engines
Ujjwal K Saha, Ph.D.
Department of Mechanical Engineering
Indian Institute of Technology Guwahati
1
Four stroke engines
2
History of Wankel Engine
Dr. Ing Felix Wankel
• Wankel first conceived the rotary engine in
1924.
• Received first patent in 1929.
• In 1951, he collaborated with NSU, a
motorcycle bulider, and equipped them
with rotary engines.
3
Other Companies that Have Produced
the Rotary
•
•
•
•
•
•
General Motors
Mazda
Ford
Mercedes-Benz (Diamler-Benz)
NSU (Neckarsulmer Strickmachinen Union)
Citroen
4
Overview
• RCE engines are Otto Cycle engines. (4 phases
in combustion cycle)
• Compression is achieved by volume reduction.
• There are three separate volumes of gas at any
point.
5
Overview
• In a piston engine the
same volume of space
does four different jobs
(intake, compression,
combustion and exhaust).
• A Rotary engine does
the same four jobs in
separate parts of the
housing.
6
Wankel Engine Cycles
•
•
•
•
Intake
Compression
Combustion
Exhaust
7
Engine Geometry
• Rotor has equilateral
curved-sided
triangular shape
• Stationary part of RC
engine has inner
contour of two-lobed
epitrochoid
8
Intake Cycle
• Vacuum pulls air fuel mixture in chamber
9
Compression
• Air- fuel mixture is compressed
10
Spark Plugs fire
• spark plugs ignite
the air/fuel mixture
• pressure quickly
builds
• forces the rotor to
move
11
Combustion cycle
• combustion
gases continue
to expand
• moving the rotor
and creating
power
12
Exhaust
• high-pressure
combustion
gases are free
to flow out the
exhaust
13
Parts
• Rotor
• Housing
• Output Shaft.
• Intake & exhaust ports
14
• Three convex faces
• Each act as piston
Rotor
15
16
H
Housing
• The
housing
is
epitrochoid in shape.
• Designed to keep all
three tips of rotor in
contact with housing
at all times.
• Creates three separate
volumes of gas at any
time during rotation.
• Housing is designed
with
four
parts
specifically dedicated
to one of the following:
Intake,compression,
combustion and exhaust.
17
Output Shaft
• Output shaft has lobes mounted offset
from the centerline of the shaft. Rotors
are mounted on these lobes.
• Each lobe acts as a crankshaft on the
piston engine.
• When rotor follows the surface of the
housing it creates torque on the lobes
making the output shaft rotate.
18
Intake and Exhaust Ports
• Ports are created in the
housing
eliminating
valves,
camshafts,
cams, lifter rods and
timing belts.
• Rotary engines have 4
or 6 ports for intake and
exhaust.
• 6 port rotary engines
use one extra intake
port per rotor used only
at higher RPM’S.
19
Differences
• No piston, cylinder, and mechanical
valves, there is a triangular rotor
• Rotary has 40 % fewer parts and
roughly 1/3 less the bulk and weight
• capable of running at unusually high
speeds for long periods of time
• motor exhibits
weight ratio
a
high
power-to20
• exceptionally good torque
curve at all engine speeds
• tremendous
horsepower
for its size
• Piston
engines
restrict
engine speed with the
valve mechanism
• piston
engine
cause
shaking and rattling
• Also there is power lost
when the piston moves
around (points of zero
momentum and speed)
21
Disadvantages
• High surface to volume ratio in
combustion chamber (two spark
plugs)
• Higher fuel consumption in naive
designs
• Higher carbon monoxide (CO)
emissions in naive designs
22
Features of Rotary engine
• No reciprocating parts.
• No separate intake-exhaust valve
mechanism.
• One explosion for one rotation of output
shaft
• No cranking mechanism required
23
Applications
•
•
•
•
•
High performance motor cycle (Comotor)
Snowmobile (Outboard marine USA)
Helicopter engine (U.S. Air force)
Industrial engine( Ingersoll-Rand USA)
Passenger cars (Maszda,Japan)
24
Cars with rotary engines
•
RX-2
•
RX-7
•
RX-5
•
RX-8
25
Future of RCE Engines
• New triple rotor
engine in
development
by Mazda Corp.
26
References
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Crouse WH, and Anglin DL,
DL (1985), Automotive Engines, Tata McGraw Hill.
Eastop TD, and McConkey A, (1993), Applied Thermodynamics for Engg.
Technologists, Addison Wisley.
Fergusan CR, and Kirkpatrick AT, (2001), Internal Combustion Engines,
John Wiley & Sons.
Gill PW, Smith JH, and Ziurys EJ, (1959), Fundamentals of I. C. Engines,
Oxford and IBH Pub Ltd.
Heisler H, (1999), Vehicle and Engine Technology, Arnold Publishers.
Heywood JB, (1989), Internal Combustion Engine Fundamentals, McGraw Hill.
Heywood JB, and Sher E, (1999), The Two-Stroke Cycle Engine, Taylor &
Francis.
Mathur ML, and Sharma RP, (1994), A Course in Internal Combustion
Engines, Dhanpat Rai & Sons, New Delhi.
Pulkrabek WW, (1997), Engineering Fundamentals of the I. C. Engine, Prentice
Hall.
Rogers GFC, and Mayhew YR,
YR (1992), Engineering Thermodynamics, Addison
Wisley.
Stone R, (1992), Internal Combustion Engines, The Macmillan Press Limited,
London.
Taylor CF, (1985), The Internal-Combustion Engine in Theory and Practice, Vol. 1
& 2, The MIT Press, Cambridge, Massachusetts.
27
Web Resources
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
http://rvgs.k12.va.us/faculty/aschuetz/physics/ STS/tri2_2003/projects/uzelac/Wankel%20Engines2.ppt
http://me.queensu.ca/courses
http://www2.hawaii.edu/~atogashi/powerpoint.ppt
http://www.sewanee.edu/physics/PHYSICS111/ PROJECTS/Rotary%20Engine.ppt
http://www.eng.fsu.edu
http://www.glenroseffa.org/
http://www.howstuffworks.com
http://www.me.psu.edu
http://www.uic.edu/classes/me/ me429/lecture-air-cyc-web%5B1%5D.ppt
http://www.osti.gov/fcvt/HETE2004/Stable.pdf
http://www.rmi.org/sitepages/pid457.php
http://www.tpub.com/content/engine/14081/css
http://webpages.csus.edu
http://www.nebo.edu/misc/learning_resources/ ppt/6-12
http://netlogo.modelingcomplexity.org/Small_engines.ppt
http://www.ku.edu/~kunrotc/academics/180/Lesson%2008%20Diesel.ppt
http://navsci.berkeley.edu/NS10/PPT/
http://www.career-center.org/ secondary/powerpoint/sge-parts.ppt
http://mcdetflw.tecom.usmc.mil
http://ferl.becta.org.uk/display.cfm
http://www.eng.fsu.edu/ME_senior_design/2002/folder14/ccd/Combustion
http://www.me.udel.edu
http://online.physics.uiuc.edu/courses/phys140
http://widget.ecn.purdue.edu/~yanchen/ME200/ME200-8.ppt 28