The Objective was to Develop a Motorcycle running on alternative fuel, in this case Methane Gas. The Project was a success and we were able to switch between petrol and gas as fuel resulting in a hybrid motorcycle. The project was featured in local and national news channels.

1. Final Year Group Project
Group Members: Amit Prem, Anup Suvarna, Varun Uthappa, Guru Prasad Shetty

2.  The main aim of the project was to develop a prototype hybrid motorcycle to run
on Compressed Natural Gas (CNG) and petrol as fuel.
 The objective of the project are as follows:
◦ Design and build working prototypes for inlet and exhaust systems to
accommodate both types of fuel.
◦ Modification to the motorcycle chassis to accommodate additional
components.
◦ Engine tuning to run CNG.
◦ Reduce Emission and do a comparative test with the two fuel types.
◦ Compare performance changes.
Aim and ObjectivesAim and Objectives

3.  Compressed natural gas (CNG) is one of the alternative fuels and in its compressed
form can play a vital role to augment the bargaining demand of diesel and petrol
in the transport sector.
 CNG as a fuel is clean and has got distinct technical, economic and ecological
advantage over conventional fuel which makes it an excellent automotive fuel.
More than the economic consideration the potential to reduce emissions will be
the main reason to promote natural gas by many countries.
 Existing petrol vehicles can use CNG by installing a bi-fuel conversion kit and then
the converted vehicles can have the flexibility of operation either on CNG or
petrol.
 CNG is a mixture of hydrocarbons consisting of approximately 80% to 90%
methane in gaseous form. Due to its low energy density, it is compressed to a
pressure of 200 to 250 kg/cm² and hence the name compressed natural gas.
IntroductionIntroduction

4.  Methane is the simplest alkaline and the principal component of natural gas.
A chemical compound with the molecular formula CH4. Methane was
discovered and isolated by Alessandro Volta between 1776 and 1778 when studying
marsh gas from Lake Maggiore.
 Methane's bond angles are 109.5 degrees. Burning methane in the presence of
oxygen produces carbon dioxide and water. The relative abundance of methane and
its clean burning process makes it a very attractive alternative fuel.
 Methane being a gas at normal temperature and pressure, is difficult to transport
from its source. In its natural gas form, it is generally transported in bulk by pipeline
or LNG carriers.
 The abundance of methane in the Earth's atmosphere in 1998 was 1745 parts per
billion, up from 700 ppb in 1750. In the same time period, CO2 increased from 278 to
365 parts per million. In addition, there is a large, but unknown, amount of methane
in methane clathrates in the ocean floors. The Earth contains huge amounts of
methane. Large amounts of methane are produced anaerobically by methanogenesis.
Other sources include mud volcanoes, which are connected with deep geological
faults, and livestock (primarily cows) from fermentation.
Methane-The Next Generation FuelMethane-The Next Generation Fuel

5.  In general, methane reactions are hard to control. Partial oxidation to methanol, for
example, is difficult to achieve; the reaction typically progresses all the way to carbon
dioxide and water.
 Methane is believed to form a formaldehyde ( H2CO). The formaldehyde gives a formyl
radical (HCO), which then forms carbon monoxide (CO). The process is called oxidative
pyrolysis:
CH4 + O2 → CO + H2 + H2O
 Following oxidative pyrolysis, the H2 oxidizes, forming H2O, replenishing the active
species and releasing heat. This occurs very quickly, usually in significantly less than a
millisecond.
2H2 + O2 →2H2O
 Finally, the CO oxidizes, forming CO2 and releasing more heat. This process is generally
slower than the other chemical steps, and typically requires a few to several milliseconds
to occur.
2CO + O2 →2CO2
 The result of the above is the following total equation:
CH4(g) + 2O2(g) → CO2(g) + 2H2O(l) + 890 kJ/mol
Where bracketed "g" stands for gaseous form and bracketed "l" stands for liquid form.
Methane-The Next Generation FuelMethane-The Next Generation Fuel

6. Constituent Approximate %
Methane 94.50
Ethane 3.20
Propane 0.60
Heavier Hydro Carbon 0.30
Carbon Dioxide 0.05
Nitrogen Gases 1.25
Other Gases 0.10
Composition of MethaneComposition of Methane

7. Properties of MethaneProperties of Methane
Property Value
Auto Ignition Temperature 813K
Adiabatic Flame Temperature 2148K
Net Calorific Value 51367kj/Cubic mt
Constant Pressure heat of reaction 47772 kj/kg
Research Octane No 130
Flammability limits in air (% by volume) 5-15
Maximum burning velocity in air at
NTP
0.39mt/sec
Molecular Weight 20.69
Gas constant 0.4018
Specific heat at Constant Pressure 1.6297 kj/kgK
Specific heat at Constant Volume 1.2279 kj/kgK

8.  It is a gas at normal condition; it forms a homogenous mixture with air, hence a
complete combustion is possible.
 Octane number is very high hence ideal fuel for S.I engine. This indicates that
higher compression ratio can be used.
 Flammability limits are wide; hence it can be operated as a lean mixture; this will
lead to low emission of carbon monoxide and nitrogen dioxide.
 Stoichiometric air fuel ratio on the mass basis is comparable to other petroleum
liquid fuel.
 It has an extremely low density as compared to liquid fuels. Hence has to be
compressed in order to reduce the storage space.
 Its calorific valve on the mass basis is better than other liquid fuels, but on the
volume basis (even at every high pressure of 220 bars) it is extremely low; hence
the storage space will have to be high even at high pressure.
 As the fuel is already available in gaseous form cold starting is possible.
Advantages of Using CNGAdvantages of Using CNG

9.  It is lighter than air; hence in the event of leakage it will rise in air and reduce the
risk of fire.
 Since the C/H ratio of methane gas is lower than petrol or diesel, its product
contain lesser carbon dioxide. This aspect is of great importance due to the
mounting concern with “GREEN HOUSE EFFECT”.
 Owing to CNG’s distinct features, it does not contaminate or dilute crankcase oil,
giving a new lease of life to the engine.
 It is pollution-free and totally environment friendly. It is non-toxic, non-corrosive,
and non-carcinogenic. Its high compression ratio reduces fuel consumption and it
cannot be adulterated or pilfered.
 CNG is an environment friendly fuel. The natural gas is mainly composed of
methane and its exhaust emissions consist of water vapours and a small fraction
of carbon monoxide. The absence of carbon and other particulates result in
negligible amount of harmful elements in exhaust fumes.
 Safer; as it is lighter and dissipates quickly. Due to this it ignites quickly, but only
when the fuel to air ratio was between 5 – 15% by volume.
Advantages of Using CNGAdvantages of Using CNG

10.  Higher Octane number in the range of 120 to 130, which is considerably higher
than 93 to 99 Octane for petrol. A high Octane number ensures that CNG fuel can
run at high compression ratio without any knocking phenomena to the piston that
will cause damage to the engine. Higher flammability compared to petrol that
makes it appropriate to run on lean burn technology.
 Because it is a clean burning fuel, it reduces the required maintenance cost of
vehicle; it can be half of petrol—oil changes can be done for more than 15,000-
30,000 km, spark plug points can be changed at intervals up to 120,000 km.
 Plenty of reserve; there is an estimated 65-70 year supply of natural gas. Besides
made from fossil fuel, natural gas can also be made from agricultural waste,
human waste and garbage. Cheaper per litre equivalent than petrol, in Europe 14-
17% less than petrol and 12-74% less expensive than diesel.
Advantages of Using CNGAdvantages of Using CNG

11.  CNG fuel has some disadvantages that limit its potential to achieve the optimum
engine performance, are as stated below:
◦ Since CNG is available in gaseous form, it has a low density. CNG from the
mixer drawn into the engine cylinder displaces approximately 8% to 10% of
Oxygen by volume. This reduces the amount of Oxygen due to larger space
occupied by the CNG in the combustion chamber.
◦ CNG has a low flame speed. Its burns slower than conventional fuels, such as
petrol and diesel. As much as 60% decrease in burning velocity has been
measured. This prolongs the total combustion duration compared with diesel
and petrol. This can cause a further reduction in the engine output of 5 to 10%.
Disadvantages of CNG SystemDisadvantages of CNG System

12.  Methane has low density and high diffusivity (three times that of petrol vapor )
hence if leaked methane is unconfined, will disperse quickly to oxygen
concentration; where it cannot burn.
 Minimum ignition energy needed to ignite methane (0.29 MJ) is higher than
petrol(0.24 MJ) hence the risk of fire is lesser.
 Higher concentration as compared to petrol is needed to burn methane (5.3% vs
1% to burn and 6.3% vs. 1.1% to detonate); methane flame is colder and is of less
heat. Its ignition temperature is high. All these aspect makes this fuel safer.
 It is non toxic, carcinogenic, caustic; contact with CNG (after expansion from high
pressure) can cause frostbite.
Safety Aspects of CNG (Compare to Petrol)Safety Aspects of CNG (Compare to Petrol)

13.  Higher CR and better flow components for CNG system. This will help to improve
engine and vehicle performance further.
 An idle speed controller that considers engine load idle, engine coolant
temperature and ambient temperature as an input and corrects the mixture
accordingly. This is similar to the idle speed control used in case of MPFI vehicles.
The vacuum solenoid operated AC kick off can also be used for this purpose.
 Experiments are being done to improve the cylinder capacity and also to reduce
the size and weight of the cylinder for better mileage of the vehicles.
Performance Improvements of CNG systemPerformance Improvements of CNG system

14. BioBike: SpecificationsBioBike: Specifications
Engine Displacement (CC) 97.2
No of cylinders 1
Stroke 2/4 4
Bore x Stroke 52.4 mm x 57.8mm
Maximum Power (bhp/rpm) 7.5/8500
Torque (Nm/rpm) 7.2/5000
Compression ratio 6.1:1
No of Gears 4
Ignition System CDI
Start (Kick/Electric) Kick
Kerb Weight 120 kg
Front Suspension Telescopic Forks
Rear suspension Spring with Hydraulic damper

15.  CNG Cylinder
 High pressure copper tubes
 Pressure regulator
 Pressure reducer
 Gas-Air mixer
 Low pressure gas tube
 Pressure gauge
 On-Off valve
BioBike: CNG system componentsBioBike: CNG system components

16.  CNG is typically stored in steel or composite containers at high pressure (3000 to
4000 lbf/in², or 205 to 275 bar). These containers are not typically temperature
controlled, but are allowed to stay at local ambient temperature.
 The cylinder used for our project is 23cm in diameter and 72cm in length.
 In order to place the cylinder onto the bike, the existing fuel tank had to be
removed. Due to the relative large size of the tank mounting the tank onto the
bike required some modification.
 The brackets for the tank were made of steel with a length of 79cm, width of 2cm
and thickness of 0.5cm. The clamp to hold the brackets were welded onto the
chassis. Because of the weight of the NGV tanks, this bracket has to withstand
great mechanical stress.
 The forces that act on it are very high and can tear it off in a collision; therefore,
this bracket must be adequately mounted, with four bolts of no less than M10
with their corresponding lock washer and nuts.
BioBike: CNG system Cylinder MountingBioBike: CNG system Cylinder Mounting

17. • The brackets for the NGV cylinders or cradles are specific for each cylinder and for each type
of vehicle.
• They are made up of the following parts: Steel bracket on which the cylinder rests, a pair of
metallic bands covered with a plastic sheath that avoids friction between the metals and a
pair of rubber straps to be placed between the cylinder and the above mentioned bracket,
also to avoid contact between the metals.
• A pressurized gas cylinder is probably the strongest component on the vehicle. Vehicles that
were totally destroyed in collisions show the only discernable component being the intact
gas cylinder.
• It is unlikely that cylinders will rupture due to collision impact. Natural gas is lighter than air
and dissipates upward quite quickly if there were a leak.
BioBike: CNG system Cylinder MountingBioBike: CNG system Cylinder Mounting

18. The installation of the high-pressure piping can
be divided into three sections.
Section 1: Filling Valve – Pressure Regulator
Section 2: Pressure Regulator – Pressure
Reducer
Section 3: Pressure Reducer – Engine Intake
Manifold
BioBike: CNG system High Pressure Copper TubesBioBike: CNG system High Pressure Copper Tubes

19.  A “loop” must be made in the Section “filling valve – pressure regulator” every
time there is a change in direction of the pipe, or only one if the pipe maintains
one direction. It is very important that this section be as short as possible, to avoid
passing over other equipment in the engine compartment. The diameter of the
copper tube which has been used is 0.7cm.
The following precautions must be taken in the Section “filling valve – NGV
cylinders”:
 Securely fasten the fuel pipe to the vehicle body using galvanized metal or plastic
clamps so that there is no movement whatsoever. The fasteners or clamps should
not be placed at a distance exceeding 600 mm.
 As in the case of the previous Section, every time there is a change in the direction
of the pipe, a “loop” must be made. The piping that goes under the vehicle must
not “hang”; it must be placed over some fixed part of the vehicle’s body that can
act as its support base.
BioBike: CNG system High Pressure Copper TubesBioBike: CNG system High Pressure Copper Tubes

20. A pressure-reducing regulator comprising of a
regulator body has an inlet port, an outlet
port, and a flow path. A valve element is
moved relative to a valve seat by a diaphragm
assembly to control gas flow along the flow
path. The regulator comprises one or more of:
A coalescing filter mounted in the inlet port
 The diaphragm assembly coupled to the
valve element via a resilient member
 A diaphragm chamber comprising a non-
constant depth in the regulator body along its
diameter
 An aspirator tube extending into the outlet
port from a passage between the diaphragm
chamber and the outlet port
 The valve seat comprising an inner seat and
a protective covering over the inner seat.
BioBike: CNG system Pressure RegulatorBioBike: CNG system Pressure Regulator

21. Reduces CNG pressure from fuel cylinder (s).
 Inlet from 250 kg/ sq .cm to a range from 0 – 250 kg/sq .cm
 Factory setting ranges from 0 to 300 kg/sq .cm
Manages gas pressure to engine fuel system.
 Must respond quickly to changing gas flow
 Must have very predictable output pressure throughout range of flow,
temperature and tank pressure.
Manages varying gas compositions.
 Discussion of Joule-Thomson effect
 Requires heat to prevent icing inside regulator
 Enable options for pressure sensor, HP and LP gas fittings, relief valve connection,
etc.
BioBike: CNG system Pressure RegulatorBioBike: CNG system Pressure Regulator

22.  The compressed natural gas enters the reducer at up to 200bar(3000psi)
pressure.
 The gas enters the 1st stage of the reducer where the pressure is reduced to
3.8 - 4.8bar. The gas pressure stabilizer technology is active.
 The gas enters the 2nd stage of the reducer where the pressure is reduced to
0.8 – 1.5bar.
 The gas enters the 3rd stage, intake manifold. Vacuum moves the membrane
according to engine load and R.P.M. A dampener provision stabilizes the flow
and prevents excessive erratic movement of the metering membrane which is
optional, assuming smooth engine operation and lowest exhaust emissions.
 A small amount of gas bypasses the 3rd stage for easy starting and idle control
(adjustable needle valve). This unique feature guaranties easy starting and
virtually eliminates the risk of backfire.
BioBike: CNG system Pressure ReducerBioBike: CNG system Pressure Reducer

23. BioBike: CNG system Pressure ReducerBioBike: CNG system Pressure Reducer

24.  In a well designed system, the exhaust can not only ‘scavenge’ the cylinder of
burnt gases, but actually suck intake charge into the cylinder at slightly more than
atmospheric pressure. Two effects contribute to this. One is to utilize the
tendency of the exhaust gases, once moving, to keep on doing so “inertia tuning”.
The other “pulse tuning” which relies on pressure waves somewhat like a two –
stroke system.
 A slight amount of back pressure is required so that the unburnt charge is not
sucked into the exhaust. Pulse tuning depends on the length and diameter of the
header pipes when the exhaust valve opens, a pressure wave travels down the
exhaust, and is reflected at the end as a wave of negative pressure. This travels
back up the pipe and helps scavenge and refill the cylinder. Exhaust gases travels
down the pipe at around 300 feet per second. But pressure waves, travel up to 5
times as fast.
BioBike: Exhaust SystemBioBike: Exhaust System

25.  The exhaust that we used has a header pipe diameter of 2.32cm and a length of
59.9cm. The aftermarket end can that was used provided a power gain of 2hp
compromising slightly for the 10% loss in power when a vehicle runs on CNG. The
end can that was used was 6.05cm in diameter with a length of 28.3cm. The total
length of the exhaust system was 88.2cm.
BioBike: Exhaust SystemBioBike: Exhaust System

26.  Due to the nature of the combustion requirement of CNG, the air entering the
engine needed to be between 5 to 15 (% by volume).
 This would not have been achieved with the regular air flow that is required for
the petrol system.
 In order to control or minimize the air entering into the engine the air inlet into
the air-box was blocked off and a hole was drilled onto the side cover. This hole
was then fitted with a threaded PVC pipe so that a cap could be threaded on.
 This arrangement enables us to limit the air flow into the engine for the
combustion of methane maintaining it within the required range.
 The advantage of performing this modification is that if the bike has to be run on
petrol at some point all the rider had to do is open the cap so as to increase the air
flow into the system for the combustion requirement of petrol.
 CNG system works only with limited air entering the engine and the stock air filter
system is essential in correctly being able to perform this process.
BioBike: Air-Box TuningBioBike: Air-Box Tuning

27. BioBike: Air-Box TuningBioBike: Air-Box Tuning

28.  The Gas-Air mixer is a simple unit which is fixed onto the carburetor with a rubber
sleeve. The Gas-Air mixer was made using Aluminium.
 It consists of a channel at the center through which air passes into the carburetor.
 The unit consists of a Gas inlet from which the low pressure gas from the pressure
reducer enters with the help of low pressure rubber hose. Inside the mixer, Air
mixes with the Gas from the pressure reducer and enters the engine through the
original intake manifold via the carburetor.
 No other modification is required for the intake of the gas into the combustion
chamber. The throttle action of the existing carburetor causing the slider to move
up and down controls the Gas-Air mixture entering the engine.
BioBike: Gas-Air Mixture TuningBioBike: Gas-Air Mixture Tuning

29. BioBike: Gas-Air Mixture TuningBioBike: Gas-Air Mixture Tuning

30. BioBike: Before ModificationsBioBike: Before Modifications

31. BioBike: Before ModificationsBioBike: Before Modifications

32. BioBike: After ModificationsBioBike: After Modifications

33. BioBike: After ModificationsBioBike: After Modifications

34. BioBike: After ModificationsBioBike: After Modifications

35. BioBike: After ModificationsBioBike: After Modifications

36. BioBike: Results - Emission comparisonBioBike: Results - Emission comparison
Constituent Petrol CNG % Reduction
Nox 11 PPM Vol 2 PPM Vol 81.82 %
CO 0.06 PPM Vol 0.02 PPM Vol 66.66 %
NO 10 PPM Vol 2 PPM Vol 80 %
HC
251 PPM Vol 166 PPM Vol
33.86 %

37.  The emission tests conducted shows a remarkable decrease in the pollutant gases
that are exhausted into the environment. Methane constitutes of 85% to 99% of
natural gas and it is the lightest hydrocarbon, this makes natural gas inherently
clean burning fuel, the test conducted proves that fact.
 Methane itself is a greenhouse gas and since its utilization results in lesser
harmful emissions when compared to petrol shows that a considerable reduction
in harmful emission and fewer greenhouse gases will be generated resulting in
slowing down of Global Warming and since methane is being utilized the results
are more beneficial to the environment and to us.
BioBike: Results - Emission comparisonBioBike: Results - Emission comparison

38.  To produce a cleaner environment for all to live and work in, the development of
alternative, cleaner fuels is essential. To encourage the use of the fuels,
competitive prices combined with good marketing techniques are required.
 Our project bike provided a millage of 110km/kg of methane while the same
engine provided a mileage of 70km/liter of petrol this meant the bike is very
cheap to run per km in methane which is 16 paisa. The total cost of the conversion
can be recovered quickly from the savings accruing by use of CNG. Moreover,
Compressed Natural Gas being a cleaner and greener fuel in comparison to
Petrol / Diesel there is less wear and tear of the engine.
 There is much less carbon deposit in the engine and also the life of Engine oil is
enhanced. One can say that on a whole 20 to 30% of bike maintenance costs are
saved by using CNG in the long run. Besides economy, there is no compromise to
the safety of the bike which is better than petrol due to the nature of the fuel.
Engine runs smoother and there is reduction in the noise or vibration of the bike.
There is a small amount of power loss but it can be compensated for by increasing
the compression ratio and by using an fuel mixture controller based on engine
loads. We ran a free flow exhaust to get a 2hp increase in power.
 Overall the project was a success and we were able to efficiently demonstrate the
use and benefits of CNG as fuel on a Motorcycle. There were a number of learning
opportunities through this project.
BioBike: ConclusionBioBike: Conclusion

39. BioBikeBioBike
Special thanks
•Engineering department for the support
•Head of Department Dr. NS Sriram
•Supervisor Mr Muralidhar
•Ashith Shetty for his support.

40. THANK YOU