automatic dual fuel engine

CHAPTER 1

STUDY OF DUAL FUEL ENGINE

1.1 INTRODUCTION:

There is an urgent need to conserve the conventional fuels, diesel and petrol, so as to reduce

the oil import bills of an oil-dependent country and also to mitigate the menace of the

environmental pollution. Automobiles can be made to run either on diesel or LPG or by both

of them. Diesel is used as the primary fuel and LPG as the secondary fuel. This dual fuel

operation enables to change from LPG to diesel or from diesel to LPG at his convenience by

automatically when the engine speed reaches 1000 rpm. On the LPG line there is an electro-

mechanical solenoid. The device closes the flow of LPG during the operation of DIESEL and

opens the LPG line when the engine is running on LPG or by both.

These fuels will have to be replaced by suitable alternative fuels like alcohols and various

gaseous fuels. Among various gaseous fuels, CNG, LPG and hydrogen are prominent. Dual-

fuel operation is found to be one of the prominent methods of conserving diesel and petrol.

There is the importance of understanding combustion process in dual-fuel engines with

regard to enhanced performance and reduced pollution.

Application:

Dual fuel engines are becoming popular in many parts of the world. Dual fuel systems

provided by small number of technologies companies are becoming increasingly popular

worldwide; however original components manufacturers are beginning to show more interest

in some of these promising technologies.

Volvo is also working on dual fuel technology for their trucks.

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Advantages:

Fuel cost savings

Significantly reduced emissions, in both diesel and gas modes

Fully rated horsepower

Lower maintenance costs & improved longevity due to cleaner fuel

Retains diesel only versatility

Significantly reduced emissions, in both diesel and gas modes

Fully rated horsepower

Retrofit system - expands capability and adds value to your present investment

Lower maintenance costs & improved longevity due to cleaner fuel

Retains diesel only versatility

Limitations:

Unable to operate at 100% in gaseous fuel

Skilled operators are needed for this operation.

Periodic maintenance is necessary due to use of dual fuels in operations

Compare to diesel mode noise is more in dual fuel mode.

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CHAPTER 2

INJECTION SYSTEM

2.1 INTRODUCTION:

A dual fuel injection arrangement for use in an internal combustion engine comprises of one

injector for injecting fuels into an inlet manifold of the engine. Here diesel is used as a

primary fuel and LPG as secondary fuel. In dual fuel injection system second fuel is supplied

at higher pressure than the first fuel.

The fuel regulator is incorporated with the non-return valve in the second fuel outlet i.e.,

Liquefied Petroleum Gas (LPG). The fuel is than passed through the flame trap to prevent

any fire accidents if there is any back flow of the gas.

Here solenoid valve is also incorporated with the outlet of the secondary fuel. So now the

secondary fuel will move out from the LPG tank and will pass to the flame trap as said above

and than through the solenoid valve and thus will finally reach to the engine cylinder.

2.2 SOLENOID VALVE:

A solenoid is a device which converts energy into linear motion and controls the flow of gas

or liquid. The electrical device causes a current to flow through a coil located on the solenoid

valve. This current flow in turn results in a magnetic field which causes the displacement of a

metal actuator.

The actuator is mechanically linked to a mechanical valve inside the solenoid valve. The

valve then changes its state; either opening or closing to allow a liquid or gas to either flow

through or be blocked by the solenoid valve. A spring is used to return the actuator and valve

back to their resting state when the current flow is removed.

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2.3 SPECIFICATION OF SOLENOID:

Helix 2 way solenoid model no. : H013/R801

2.4 WORKING:

This valve is a control unit which, when electrically energized or de-energized, either cut off

or permits fluid flow. The actuator is an electromagnet. When the valve is energized, a

magnetic field builds up which pulls a plunger against the action of a spring. When de-

energized, the plunger or pivoted armature is returned to its original position by the action of

the spring.

In this normally closed type solenoid valve, the seat seal is attached to the solenoid core. In

the de-energized condition, a seat orifice is closed, which opens when the valve is energized.

This two-way valve is a shut-off valve having one inlet port and one outlet port. The inlet

port facilitates the introduction of gas from the outlet of the flame trap through a pipe into the

valve. Through the outlet of the valve the gas goes into the air gas mixture adapter, from

which it is then sent into the combustion chamber. The coil of the valve is connected to the

electric source which energizes or de-energizes it.

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TYPE 2- WAY, NORMALLY CLOSED

MEDIA GAS

NET WEIGHT 300 GM

PRESSURE RANGE 0-10 bar

OPERATING ENVIROMENT 4-66A C

PORTING G ¼

VOLTAGE 12 VDC

POWER 2.5 WATTS

In the de-energized condition, the core spring, assisted by the pressure of the fluid, holds the

valve seal on the valve seat, shutting off the flow. When energized, the core and seal are

pulled into the solenoid coil and the valve opens. The electromagnetic force is greater than

the combined spring force and the static and dynamic pressure forces of the medium.

The valve is controlled by means of an electric switch. When the switch is in on condition,

the valve gets energized and allows the flow of gas from the flame trap to the air- gas mixture

adapter. The off condition of the switch de-energizes the flow thus terminating the flow of

gas.

FIG. 1 CUT SECTION OF SOLENOID VALVE

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2.5 FUEL INJECTOR:

Fuel injected engines employ fuel injectors, each of which delivers a metered quantity of fuel

to an associated engine cylinder during each engine cycle. Prior fuel injectors were of the

mechanically or hydraulically actuated type with either mechanical or hydraulic control of

fuel delivery. More recently, electronically controlled fuel injectors have been developed. In

the case of an electronic unit injector, fuel is supplied to the injector by a transfer pump. The

injector includes a plunger which is movable by a cam-driven rocker arm to compress the

fuel delivered by the transfer pump to a high pressure. An electrically operated mechanism

either carried outside the injector body or disposed within the injector proper is then actuated

to cause fuel delivery to the associated engine cylinder.

Prior fuel injector designs have included high pressure fuel passages extending around a

central recess containing a solenoid coil and a solenoid armature. Because the overall size of

the fuel injector is limited, the size of the solenoid must also be limited, thereby undesirably

reducing the available solenoid force. In addition, the high pressure fuel passage must include

turns and bends in order not to intersect the solenoid recess, thereby complicating formation

of the passages and requiring the use of plugs to seal off portions of the passages after

formation. Because of the increase in the path length of the fuel passages, relatively large

forces must be placed on the various parts in order to achieve proper sealing, thereby leading

to part deflections which can undesirably affect the various components.

Quick and complete combustion is ensured by a well designed fuel injector fuel injector. By

atomizing the fuel into fine droplets, it increases the surface area of the fuel droplets resulting

in better mixing and subsequent combustion. Atomizing is done by forcing the fuel through a

small orifice under high pressure.

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The injector assembly consists of

A needle valve

A compression spring

A nozzle

An injector body

FIG. 2 INJECTOR

When the fuel is supplied by the injection pump it exerts sufficient force against the spring to

lift the nozzle valve, fuel is sprayed into the combustion chamber in a finely atomized

particles. After, fuel from the delivery pump gets exhausted, the spring pressure forces the

nozzle valve back into its seat. For proper lubrication between nozzle valve and its guide a

small quantity of fuel is allowed to leak through the clearance between them and then drained

back to fuel tank through leak off connection. The spring tension and hence the valve opening

pressure is controlled by adjusting the screw provided at the top.

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2.6FLAME TRAP:

FIG. 3 FLAME TRAP

The flame trap is used to prevent the return fire to the cyclinder back fire can be prevented by

water present in it. There wull be one inlet and one outlet. Totally our cylinder capacity is

9.5litre and the overflow valve thickness is 5mm all over the diameter, material is mild steel.

The inlet pipe will be dipped inside the water to prevent the fire. If the fire occurs, water will

take off the fire.

APPLICATION:

To stop the spread of an open fire.

To confine fire within an enclosed controlled location.

To limit the spread of an explosive event that has occurred.

To protect potentially explosive mixtures from igniting.

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CHAPTER 3

OPERATION OF SOLENOID

3.1 LIST OF COMPONENTS:

LIST OF COMPONENTS

S.NO PARTS MATERIAL QUANTITY

1. Gas regulator Brass 1 nos

2. “1/2” gas hose Rubber 5 nos

3. “1/2” hose nipple Brass 8 nos

4. Pressure gauge range from 0-10 kg/cm2

--- 2 nos

5. Solenoid valve --- 1 nos

6. “1/2” brass valve Brass 2 nos

7. Flame trap Mild steel 1 nos

8. Aluminium gas mixture adapter Aluminium 1 nos

9. Hexagonal nipple Brass 3 nos

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3.2 ENGINE SPECIFICATION:

SPECIFICATION OF THE ENGINE

Engine Four stroke engine cyclinder

Brake power 5 horse power

Revolution per minute(RPM) 1500

Fuel Diesel

No. of cylinder One

Bore length 80mm

Stroke length 110mm

Starting Cranking

Working cycle Four stroke

Method of cooling Water cooled

Method of ignition Compression ignition

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3.3 EXPERIMENTAL SET UP:

A single cylinder, 4-stroke, water cooled diesel engine of 5.2vkw rated power is considered

for the purpose of experimentation. The engine is coupled to an eddy current dynamometer

through a load cell. It is integrated with a data equisition system to store the data for the off-

line analysis.

Necessary provisions are made to regulate and measure the flow rates of air, fuel and the

coolant. Initially, the engine is operated on the diesel baseline mode at a constant speed of

1500 rpm at 10%, 20%, 30% etc of the full load upto the full load.

Then the engine is operated on the dual fuel mode at different loads using various proportions

of diesel and LPG by energy, like 90-10, 80-20, and so on.

In the 90-10 mode of operation, 90% of the heat is supplied due to the combustion of diesel

and 10% of the energy is supplied due to the combustion of LPG. Combustions of diesel and

LPG, the lower calorific value of diesel is taken as 43000kj/kg while that of LPG is taken as

45700kj/kg.

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3.4 THEORY OF OPERATION:

The main feature of dual fuel engine is simultaneous combustion of two types of fuel in its

combustion chamber. The most typical combustion is diesel oil and Liquified Petroleum

Gases (LPG). Diesel oil combustion is decreased and missing energy input is covered by

LPG. The decreased amount of diesel oil is called ignition portion and it’s main function is to

provide ignition for LPG and air mixture.

Initially the engine will start with diesel fuel as we cannot use LPG, as because LPG requires

a very high temperature to burn which cannot be attained in the compression ignition engine.

Once the engine starts with diesel the temperature inside the combustion chamber increases

and thus we can change the mode to LPG. When the switch is ON position the solenoid valve

gets energized as the current flows to the electric coil which in turn creates magnetic field and

thus displace the metal actuator. The actuator is mechanically linked with valve. The valve

than changes the state of position either opening or closing to allow the flow of gases to flow

through the solenoid valve. A spring is also used to return the actuator in original position

when current flow is removed.

When the solenoid switch is switched ON, the LPG will move out from the cylinder and

moves in the flame trap through pressure gauge where we can measure the pressure of the

LPG. After that the LPG will flow through the pressure reducing valve where we can adjust

the pressure of the LPG as per the requirement of the system. Now the LPG will move to the

aluminium gas mixture adaptor where the LPG will mix up with the air and thus penetrate to

the combustion chamber where it combines with the atomized particles of the diesel which is

feed by the injector.

The brake power of the engine was found to be about 15% more on the dual fuel operation,

while the brake specific fuel consumption was found to be about 30% lower than diesel fuel

mode of operation. This could be due to better mixing of air and LPG and hence improves

combustion efficiency. Here LPG is used as a partial replacement of diesel in the dual fuel

mode of operation.

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CHAPTER 4

EXPERIMENTATION

4.1 TABULATION:

TABL

E 1:

DIE

SEL

MAN

OM

ETER

READ

ING h2 30 33 31 33

h1 80 77 79 77

TEM

PERA

TURE

READ

ING

T6 35 35 36 36

T5 85 98 114

133

T4 120

148

179

218

T3 29 29 30 30

T2 34 35 36 38

T1 28 28 28 27

TIM

E

TAKE

N

FOR

1Occ

DRO

P

75 55 40 32

LOAD 0 5 10 15

RPM

1500

1500

1500

1500

SL.

NO

.

1 2 3 4

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TABL

E 2:

DIE

SEL

+ LP

G

MAN

OM

ETER

READ

ING h2 30 32 34 34

h1 80 78 76 76

TEM

PERA

TURE

READ

ING

T6 36 38 39 39

T5 92 116

127

145

T4 154

191

218

255

T3 31 31 31 31

T2 33 33 35 36

T1 30 29 28 28

TIM

E

TAKE

N

FOR

1Occ

DRO

P

85 72 55 36

LOAD 0 5 10 15

RPM

1500

1500

1500

1500

SL.

NO

.

1 2 3 4

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Where, T1= Inlet water temperature of engine jacket.

T2= Outlet water temperature of engine jacket.

T3= Outlet water temperature from calorie meter.

T4 = Exhaust gas temperature from the engine.

T5 = Exhaust gas temperature from the calorie meter.

T6 = Room temperature

4.2: CALCULATIONS:

FORMULAE USED:

MECHANICAL EFFICIENCY(ƞm) =

BREAK THERMAL EFFICIENCY(ηbth) =

INDICATED THERMAL EFFICIENCY(ηith) =

WHERE,

B.P = BRAKE POWER = kW

I.P = INDICATED POWER = RATED POWER

mf = MASS OF FUEL PER SEC.

c = CALORIFIC VALUE OF FUEL

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T = R S

Where, R = RADIUS OF THE ARM = 0.13 m

S = LOAD in kg

MECHANICAL EFFICIENCY :

AT LOAD 5kg, ƞm= = 27%



BREAK THERMAL EFFICIENCY (DIESEL AND LPG):

AT LOAD 5kg, ƞbth= = 19.63%



BREAK THERMAL EFFICIENCY (DIESEL):

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AT LOAD 10kg, ƞbth= = 22%


INDICATED THERMAL EFFICIENCY (DIESEL AND LPG):




INDICATED THERMAL EFFICIENCY (DIESEL):

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AT LOAD 5kg, ƞbth= =54.9%

AT LOAD 10kg, ƞbth= =39.9%

AT LOAD 15kg, ƞbth= =32%

4.3 GRAPHICAL REPRESENTATION:

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CHAPTER 5

PART AND ASSEMBLY DRAWINGS

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EXPERIMENTAL SETUP LAYOUT :

FIG. 4 EXPERIMENTAL SETUP LAYOUT

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FIG.5 : FUEL INJECTOR

FIG.6 : FLAME TRAP

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FIG. 7 : SOLENOID VALVE

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CHAPTER 6

SNAP SHOTS

CHAPTER 7

CONCLUSION

Dual fuel operation is more convenient and economical for conserving the precious

conventional liquid fuels. A diesel base line engine could be operated on the dual fuel mode

with minor changes. The following conclusions have been made from the above work.

• The engine operation is smoother and more efficient particularly at high engine loads,

• At lower loads, mechanical, brake thermal efficiencies of the engine are more on the pure

diesel mode but at higher loads the reverse is true.

• The engine operation is more economical on the pure diesel mode at lower loads, however

at higher loads dual-fuel operation is better.

• The smoke density is negligible on the dual-fuel mode with higher LPG energy

substitutions.

• Stationary diesel engines can be conveniently operated on the dual-fuel mode at higher

loads.

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CHAPTER 8

REFERENCES

1. Performance evaluation of a dual fuel engine (Diesel + LPG) – Patent submitted by

G.A. Rao, A.V.S. Raju, K. GovindaRajuluand C.V. Mohan Rao, Dr.Paul Raj

Engineering College, Bhadrachalam, Dist.Khammam-507111 (A.P.), India

2. Dual Fual Injection System – Wikipedia.

3. Solenoid Valve – Wikipedia.

4. Wisegeek.(website).

5. A Study on the Solenoid Valvein Diesel Engine - Qing Yang, Hongguang Zhang,

Guansheng Huang, YoutongZhang, Changqichen(Department of vehicle engineering,

Beijing Institute of Technology, Beijing 100081

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automatic dual fuel engine

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