Man has always been in pursuit of energy to meet his ever increasing demands. Nowadays due to increase in pollutions and global warming, there is a need for use of eco friendly fuels. In this project attempt has been made to use LPG as an alternative (secondary) fuel for two wheeler of four stroke engine. By using LPG, efficiency of engine can be increased and pollutions caused due to emissions can be reduced. Separate LPG fuel supply system (Gas Kit) has been installed through which LPG is supplied to carburetor directly. By this both Gasoline and LPG can be used in a single vehicle. According to our requirements we can change the supply of fuel to the engine. The changes required to install LPG to the vehicle are discussed below. When the vehicle is running at lower speed LPG is suitable and at higher speed Gasoline is suitable. So, this concept of using both Gasoline and LPG as fuel is suitable for cities where operation of vehicle is in lower speed due to the traffic. Hence by using this concept we save money in buying fuel and also reduce pollutions caused. Keywords:Liquefied Petroleum Gas (LPG); LPG Fuel Supply System (Gas Kit); Four Stroke Spark Ignition Engine; Performance, Emission Characteristics

1. International Journal of Education and Research Publication (IJREP)-2018,
Volume-1, Issue-1
Available at Online :www.ijerp.org
JERP Volume-1, Issue-1, July-2018 1 | P a g e Copyright@ IJERPPublication-2018
Liquefied Petroleum Gas (LPG) as an
Secondary Fuel in 4-Stroke SI Engine
Balu A1
, Manu Kumar D M2
Department of Mechanical Engineering
G Madegowda Institute of Technology, VTU Belgaum, Karnataka India
Email: balugowda.2505@gmail.com1
, gowdadmk@gmail.com2
Abstract: Man has always been in pursuit of energy to meet his ever increasing demands. Nowadays due to
increase in pollutions and global warming, there is a need for use of eco friendly fuels. In this project attempt
has been made to use LPG as an alternative (secondary) fuel for two wheeler of four stroke engine. By using
LPG, efficiency of engine can be increased and pollutions caused due to emissions can be reduced. Separate
LPG fuel supply system (Gas Kit) has been installed through which LPG is supplied to carburetor directly. By
this both Gasoline and LPG can be used in a single vehicle. According to our requirements we can change the
supply of fuel to the engine. The changes required to install LPG to the vehicle are discussed below. When the
vehicle is running at lower speed LPG is suitable and at higher speed Gasoline is suitable. So, this concept of
using both Gasoline and LPG as fuel is suitable for cities where operation of vehicle is in lower speed due to the
traffic. Hence by using this concept we save money in buying fuel and also reduce pollutions caused.
Keywords:Liquefied Petroleum Gas (LPG); LPG Fuel Supply System (Gas Kit); Four Stroke Spark Ignition
Engine; Performance, Emission Characteristics.
1. Introduction
Nowadays in Automobile field most of the
engines use Gasoline (Petrol) and Diesel as their fuel in
spark and compression ignition engines respectively.
Basically both the fuels are obtained from the crude oil.
Now the world is facing the problem of decrease in
availability of crude oil (Petroleum) in bulk and
insufficient for future decades. Hence an alternative
fuel is essential to fight against the scarcity. Hence in
this project we have selected LPG as alternative fuel.
LPG stands for liquefied petroleum gas. It is referred as
simple propane or butane. LPG is flammable mixtures
of hydrocarbon gases which is used as fuel. It is
increasingly used as an aerosol and a refrigerant
replacing chlorofluorocarbons in an effort to reduce
damage to the ozone layer. When using in vehicle it is
known as auto gas. LPG is prepared by refining
petroleum or wet natural gas and is almost completely
derived from fossil fuel sources. The mixture of
liquefied hydrocarbon gases C3-C4 (Propane and
Butane), called colloquially liquefied gas or LPG, is a
particular energy carrier, counted among the group of
alternative fuels. LPG has more than 1000 different
uses, including applications in industry, civil
engineering, communal economy, agriculture,
households, and transport. Because of simplified
logistics of transport ensuring supply diversification,
availability of sources, and most of all environmental
aspects, LPG exhibits high dynamics of production and
consumption; the global production of this fuel comes
close to 280 million tones. LPG in IC engine reduces

2. International Journal of Education and Research Publication (IJREP)-2018,
Volume-1, Issue-1
Available at Online :www.ijerp.org
JERP Volume-1, Issue-1, July-2018 2 | P a g e Copyright@ IJERPPublication-2018
the emission of hydrocarbons, nitrous oxide and carbon
dioxide to half the value of emission by using
Gasoline. LPG has high volatility that it it will be in
gaseous state in atmospheric pressure. But it can be
converted into liquid state very easily under pressure.
Since the world is facing major problem of various
pollutions, the use of LPG helps to reduce the pollution
level. LPG gas kit concept can be adapted to on road
vehicles by cheaper costs and the cost of newly
produced vehicles containing gas kit will be decreased
due to cheaper fuels used.
2. Objectives of Project
 Increasing efficiency of the vehicle.
 Avoiding emission of harmful gases to
atmosphere by burning a clean fuel.
 Preventing scarcity of commercial
fuels(Petrol, Diesel) by reducing their use.
3. Requirement for using alternating fuel
As we all know that most of all the automobiles
use Petrol and Diesel as their fuel in large quantity. But
nowadays the world is facing a serious problem of
decrease in availability of crude oil deposits day by day
and insufficient for future decades. Hence alternative
fuel is essential to fight against scarcity.Some of the
alternative fuels are experimented by various
manufacturing units with technicians and listed below.
 Methyl Alcohol
 Compressed Natural Gas (CNG)
 Liquefied Petroleum Gas (LPG)
In this project we have preferred LPG as alternative
fuel in four stroke engine.
Comparison of Gasoline and LPG
PROPERTIES OF
FUEL
GASOLINE LPG
Chemical structure
C7H17 C4 to
C12
C4H10
Octane Number 87-94 110-112
Energy Density 46.4MJ/kg 49.6MJ/kg
Stoichiometric air fuel
ratio
14.7:1 15.5:1
4. Methodology
4.1 Assembly
In this section we have discussed about the
assembly of Gas kit into the four stroke
engine. We use the bike of following
specification.
4.1.1Technical specifications of Engine
Bike Name: Hero Honda Splendor Plus
Cooling system: Air cooled, OHC
Strokes: 4
Number of cylinder: 1
Compression Ratio: 9.9:1
Maximum Power: 6.15kW @ 8000rpm
Maximum Torque: 8.05Nm @ 5000rpm
To get the system working, we put the LPG
cylinder into a bag, and hanged it on the rear side of
bike. The LPG converter (Gas Kit) is fixed under the
fuel tank, right side of the bike. The gas pipe is
connected to the inlet of Gas kit, and the outlet pipe
through which regulated gas supply comes out is
connected to inlet of the carburetor. Vacuum pipe from
gas kit is connected to the cylinder. It is also important
that methods we used are very easy but should have

3. International Journal of Education and Research Publication (IJREP)-2018,
Volume-1, Issue-1
Available at Online :www.ijerp.org
JERP Volume-1, Issue-1, July-2018 3 | P a g e Copyright@ IJERPPublication-2018
good knowledge in auto technology and natural gas
properties.
Fig 1: Bike connected with LPG
Fig 2: Gas kit fitted to petrol engine bike
4.2Results and conclusion
After implementing Gas kit to our Bike we performed
following tests
4.2.1 Emission Test: We check the
emission of our bike by multi gas
analyzer at Government emission testing
centre. The emission results are discussed
below.
Comparison of emission from LPG and Gasoline
Emission Gasoline (Petrol) LPG
CO in % Vol 0.71 0.11
HC in PPM 807 631
CO2 in % Vol 4.20 0.10
O2 in PPM 15.0 19.7

4. International Journal of Education and Research Publication (IJREP)-2018,
Volume-1, Issue-1
Available at Online :www.ijerp.org
JERP Volume-1, Issue-1, July-2018 4 | P a g e Copyright@ IJERPPublication-2018
Fig 3: Emission Test Certificate for using LPG
Fig 4: Emission Certificate for using Gasoline
Graph 1: HC Emission v/s Brake Power
From Graph 1, it is found that as the Brake Power (BP)
increases, HC emission increases. Compared to LPG,
HC emission is more from Gasoline.
Graph 2: CO Emission v/s Brake power
From Graph 2, it is found that as the Brake Power
increases the emission of Carbon monoxide increases.
Compared to LPG emission of CO is more from
Gasoline.
Graph 3: CO2 Emission v/s Brake Power
From Graph 3, it is found that emission of Carbon
dioxide increases with increase in Brake power.
Compared to LPG emission of CO2 is more from
Gasoline.
4.2.2 Efficiency: We calculated the
efficiency of our engine by using LPG as
well as Gasoline in same engine. The
results are discussed below.
Comparison of Performance from LPG and Gasoline
Engine
cc
Gasoline
km/ltr
Rs/km
LPG
km/kg
Rs/km
100cc to
125cc
50km/ltr 1.14 80km/kg 0.48
0
100
200
300
400
500
600
700
800
900
1000
0 kW 0.5 kW 1.0 kW 1.5 kW
HCemissioninPPM
BP in kW
Petrol
Gas
0
0.2
0.4
0.6
0.8
1
0 kW 0.5 kW 1.0 kW 1.5 kW
COemissionin%volume
BP in kW
Petrol
Gas
0
1
2
3
4
5
6
0 kW 0.5 kW 1.0 kW 1.5 kW
CO2emissionin%
volume
BP in kW
Petrol
Gas

5. International Journal of Education and Research Publication (IJREP)-2018,
Volume-1, Issue-1
Available at Online :www.ijerp.org
JERP Volume-1, Issue-1, July-2018 5 | P a g e Copyright@ IJERPPublication-2018
5. Advantages
 Efficiency of LPG is greater than remaining fuels.
 Complete combustion takes place as it is in
vaporized form.
 Due to complete combustion exhaust rate
decreases and there by pollution is reduced.
 LPG improves the life of the engine and reduces
noise and vibration.
6. Limitations
 Less LPG refueling stations in cities.
 Rural areas don’t have LPG gas refueling
stations.
 Small LPG tank.
 Little risky to handle LPG under pressure of
about 18 bars.
7. Conclusion
From the above results of various
tests conducted, we conclude that using LPG
as fuel in four stroke engine, emission of
harmful gases into atmosphere can be reduced
and high efficiency compared to Gasoline fuel
in engine can be achieved. This reduces the
expenditure made for purchasing fuels.
8. Scope of future work
The project has been divided into two phases. In
first phase Performance and Emission
characteristics has been determined for four stroke
engine using both LPG and Gasoline. The second
phase is in progress, where Design and
Fabrication of two chambered Fuel tank is done.
In this two chambered fuel tank we can store LPG
and Gasoline simultaneously through which it can
be supplied to carburetor according to our
requirement. In future if LPG reaches extinct
condition, we can use Hydrogen Gas or any other
fuels like bio fuels in the place of LPG in same
tank.
9. Reference
[1] “CNG:Alternative fuel for two wheeler”
International journal of advanced technology in
engineering and science. Volume 2, special issue 1,
September 2014
[2] “Conversion of petrol bike into LPG and
emission Check” International journal of
mechanical engineering and technology
Volume 6, issue 4, April (2015), pp. 65-71
[3] “LPG as alternative fuel for two wheelers”
International journal of innovative research in
science, engineering and technology. Volume 6,
special issue 8, may 2017