UEAUA36 TWO AND THREE WHEELERS
BY.
B.HARISHBABU Asst.prof,VTU
UNIT I
2
Four Stroke SI Engine
Stroke 1: Fuel-air mixture introduced into cylinder
through intake valve
Stroke 2: Fuel-air mixture compressed
Stroke 3: Combustion (~constant volume) occurs
and product gases expand doing work
Stroke 4: Product gases pushed out of the cylinder
through the exhaust valve
FUEL
A
Ignition
I
R
Fuel/Air
Mixture
Intake
Stroke
Compression
Stroke
Combustion
Products
Power
Stroke
Exhaust
Stroke
3
Spark plug for SI engine
Fuel injector for CI engine
Cylinder
Components
Valves
Top
Center
(TC)
Stroke
Bottom
Center
(BC)
TC
0o
Crank shaft
q
270o
90o
180o
BC
Clearance
volume
Cylinder
wall
Piston
Four-Stroke SI Engine
Exhaust gas
residual
IVO - intake valve opens, IVC – intake valve closes
EVO – exhaust valve opens, EVC – exhaust valve opens
Xb – burned gas mole fraction
Two Stroke SI Engine
Exhaust
port
Fuel-air-oil
mixture
compressed
Check
valve
Expansion
Exhaust
Intake (“Scavenging”)
Crank
shaft
Fuel-air-oil
mixture
Compression
Ignition
Rotary Combustion Engines
7
Rotor Visual & Explanation
8
9
Two-Stroke Scavenging
Cross
Loop
Uniflow
UNIT II
11
Two-Stroke SI Engine
scavenging
Exhaust area
Intake area
EPO – exhaust port open
EPC – exhaust port closed
IPO – intake port open
IPC – intake port closed
Cylinder Arrangement
Single-cylinder engine gives one power stroke per crank revolution
(2 stroke) or two revolutions (4 stroke). The torque pulses are widely
spaced, and engine vibration and smoothness are significant problems.
Used in small engine applications where engine size is more important
Multi-cylinder engines spread out the displacement volume amongst
multiple smaller cylinders. Increased frequency of power strokes
produces smoother torque characteristics. Engine balance (inertia forces
associated with accelerating and decelerating piston) better than single
cylinder.
Most common cylinder arrangements:
- In-line 4-cylinder
- In-line 6-cylinder
- V-6 and V-8
Power Regulation (Throttling)
An IC engine is basically an air engine, the more air you get into the
cylinder, the more fuel you can burn, the more power you get out.
The initial pressure in the cylinder is roughly equal to the pressure
in the intake manifold.
Pressure in the intake manifold is varied by opening and closing the
throttle plate to change the pressure drop. Maximum air flow (and
power) achieved at wide-open-throttle (WOT). Minimum air flow
at idle
Fuel
Patm
Pint < Patm
Idle
Intake manifold
WOT
Basic Carburetor Design
Air Flow
Venturi
Fuel
Throttle
Mixture to manifold
Fuel Injection System
Air intake
manifold
Throttle
Fuel tank
During start-up the components are cold so fuel evaporation is very slow, as a result
additional fuel is added through a second injecting valve
Superchargers are compressors that are mechanically driven by the
engine crankshaft and thus represent a parasitic load.
Patm
Pint > Patm
Compressor
Turbochargers couple a compressor with a turbine driven by the exhaust
gas. The compressor pressure is proportional to the engine speed
The peak pressure in the exhaust system is only slightly greater than
atmospheric – small DP across turbine.
In order to produce enough power to run compressor the turbine speed
must be very fast (100k-200k rev/min). It takes time for the turbine to
get up to speed so when the throttle is opened suddenly there is a delay
in achieving peak power - Turbo lag.
Waste gate valve controls the exhaust gas flow rate to the turbine.
It is controlled by the intake manifold pressure
EXHAUST
FLOW
INTAKE
AIR
Electronic ignition system
20
A centrifugal clutch is a clutch that
uses centrifugal force to connect two
concentric shafts, with the driving shaft
nested inside the driven shaft.
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Chassis
The two-wheeler chassis consists of the frame, suspension,
wheels and brakes.
The chassis is what truly sets the overall style of the two-wheeler.
Automotive chassis is the main carriage systems of a vehicle. The type
determines the gearing configuration, flex and the type of modifications
that can be accommodated.
Frame: The frame serves as a skeleton upon which parts like
gearbox and engine are mounted. It can be made of steel, aluminum or
an alloy. It keeps the wheels in line to maintain the handling of the twowheeler.
Suspension: It is a collection of springs and shock absorbers. It
can be of two types: front suspension and rear suspension. It insulates
both the rider and the bulk of the machine from road shocks and also
keeps the wheels in the closest possible contact with the ground and
gives control of the vehicle to the rider. The front suspension helps to
guide the front wheel, to steer, to spring, to dampen, and to provide
support under braking.
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Types of Frames:
Motor cycles / Mopeds use three basic frame designs:
1.Cradle Frame, (2) Back Bone Frame, (3) Stamped Frame
The cradle frame is one of the most enduring type and is shown in figure
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Stamped underbone frame
Details of shock absorber
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Wheels: A wheel is a circular object which with an axle, allows
low friction in motion by rolling. A wheel is made up of the rim and spokes
or disc plate. Wheels should be aligned properly because it directly
influences driving. Two-wheeler wheels are generally of aluminum or
steel rims with spokes.
Brakes: Generally, there are two independent brakes on a twowheeler: one set on the front wheel and one on the rear, however, there
are many models which have 'linked brakes' and apply both at the same
time. The front brake is generally much more powerful than the rear
brake. Brakes can either be drum or disc based. When the rider operates
one of the brakes, a fluid element known as hydraulics is pressurized to
provide the required forces to squeeze the brake pad material onto the
rotor and slow down or stop the vehicle.
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Gear Box:
The motorcycle gear box contains a number of gears in different
sizes. In the process of gear switching, different pairs of gearwheels lock
together. A large and small wheel lock together in the lowest or slowest
gear. Similar size wheels lock together in the highest or fastest gear.
The motorcycle gear box is the component that makes the actual ratio
between the engine and the driving wheels. It is also referred to as
transmission gear.
Types of Motorcyle Gear Box:
In a general manner, the motorcycle gear box can be of three
types, they are:
Horizontally Split: It has a seam on the horizontal plane.
Vertically Split: It has a seam on the vertical plane.
Cassette Type: The gears are loaded in from one side.
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Characteristics of Gear Box:
The gears are constantly meshed with one another and they
are always spinning.
Uses of Gear Box:
It controls gear and shaft alignment.
It controls the engine RPM.
It protects the gears and lubricants from water, dust and other
environmental contaminants.
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Functions of Two Wheeler Shock Absorbers:
They absorb the shock from bumps on the road and helps to
1.make riding safe and smooth.
2.they allow the use of soft springs while controlling the rate of
3.suspension movement in response to bumps.
4.They also, along with hysteresis in the tire itself, damp the motion of
the unsprung weight up and down on the springiness of the tire.
5.Shock Absorber system make the vehicle manageable.
Materials used for making Shock absorbers:
The most commonly used materials for making these absorbers are:
Steel
Aluminum
Maintenance of Shock Absorbers:
It should be checked regularly.
Oils should be changed according to the recommended time.
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Suspension system
Introduction:
A Motorcycle Suspension System consists of a spring coupled to a
viscous damping element, a piston, in a cylinder filled with oil. The piston
smooths out vibrations induced by the vehicle while moving as it moves
through the oil. The flow of oil through the piston is regulated by an
adjustable elastic deformable flap called a shim.
Types of Motorcycle Suspension:
Front Suspension: The predominant type of front suspension is
the suspension fork. The bottom part of the fork is fitted over the
tubes that connect the fork to the frame. When the vehicle hits a
bump, the spring gets compressed and the piston forces fluid
through the orifice.
Rear Suspension: Most of the time the rear suspension are used
as a shock absorber
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Functions of Motorcycle Suspension:
The main functions of the motorcycle suspensions are:
To insulate both the rider and the bulk of the machine from road
shocks. It makes a much safer and comfortable ride and is
important for proper mechanical reliability and longevity.
To keep the wheels in the closest possible contact with the ground
and gives control of the vehicle to the rider.
The front suspension helps to guides the front wheel, to steer, to
spring, to dampen, and to provide support under braking.
Materials used for making Suspensions:
The materials most commonly used for making suspensions are:
Steel
Aluminum
Maintenance of Suspensions:
The suspensions should be checked for loose nuts and bolts and
leaks.
The swing arm bearings should be lubricated monthly.
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UNIT III
33
Disk brake
Components of Disk brake:
brake calipers
brake pads
rotors
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Drum brake
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Wheel parts:
A wheel is a circular object which with an axle, allows low friction in
motion by rolling. A wheel is made up of the rim and spokes or disc
plate. The standard size of wheels for two-wheelers is 17 inch. Wheels
should be aligned properly because it directly influences driving.
Parts of a Wheel:
There are two basic parts of a Wheel:
Tire
Wheel Rim
Wheel Spoke or Compact Disc
Tire is also an important part of a wheel. It works as a wheel only after it
is installed on the rim and is inflated.
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Two types of spokes.
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Split disc wheel
Spoked wheel transmits driving
torque and braking torque through
different set of spokes.
Wheel hub details
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Materials used for making Motorcycle Wheel Parts:
Wheel for two-wheelers are usually made of aluminum. Magnesium is
also used for making wheels, but they are meant for race bikes
because they are very strong and light. Even carbon fibers are also
used for making wheels.
Maintenance of Motorcycle Wheel Parts:
Though a simple device, the wheel needs proper care and
maintenance to keep it taut and free of damage and in perfect
balance.
Regular inspection for loose or damaged spokes is a must.
They must be kept clean and free of rust.
The wheel should be aligned properly otherwise it can wear the tires,
reduce tire mileage and impair steering and cornering.
Proper checking of the wheels to insure that they are in good
condition is a must because cracked or bent wheel can lead to the
loss of air and cause subsequent deflation of the tire.
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Tyre
A Rubber Tire is a device covering the circumference of a wheel. It
is an essential part of most ground vehicles. The combination of air
with rubber tire supports the vehicle and its contents.
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Part of a tyre
Figure: Simple tyre tread patterns
Tyre wear: (1) Skid depth. (2) Side
wall. (3) Wear indicator
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Tyre road contact for different extent of tyre inflation: (a) Correct inflation. (b) Under inflation, tyre cries “May
side walls are heated due to bending. I need more air”. (c) Over inflation.
Tyre rotation
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Parts of a Rubber Tire:
The Bead: fits inside the rim of the wheel and is held in place by tire pressure.
The Sidewall: protects the cord plies and has all the tire information printed on it.
The Tread: provides strength and stability and is the interface that provides
traction to the road surface.
The Belt Plies and Body Plies: give the tire its stability and resistance to road
damage.
An inner liner: combats permeability (keeping the air in the tire).
Sipes: are small slits in the tread that improve traction.
Functions of Rubber Tires:
Rubber Tire absorbs the shock of road roughness and can provide a smooth, safe
ride.
They protect the wheel from wear and tear.
They provide a high-friction bond between the vehicle and the road to improve
acceleration and handling.
They also provide other functions such as traction for moving, stopping and steering
as well as providing a cushion for the vehicle
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UNIT IV & V
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Two wheelers
Case study to Two wheeler and three wheeler
www.iatss.or.jp/pdf/research/28/28-1-03.pdf
www.ccsindia.org/ccsindia/policy/live/studies/wp00
65.pdf
www.tvsmotor.in/pdf/analystmeet2005.pdf
http://www.ustudy.in/node/2103
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Motor Cycle components
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Unit 5: Three Wheelers
Case study of Autorickshaws, Pick up vans, delivery van and Trailer
– servicing and Maintenance.
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For details
www.tvsmotor.in
http://www.jsauto.co.in/
www.alibaba.com/showroom/three-wheelermanufacturer-in-india.html
www.pal3wheeler.com/
www.bajajauto.com/commercial_vehicle.asp
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Thank you
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