Compressed Air Engine Modified Four Stroke Single Cylinder Petrol Engine Working on 2 Stroke Compressed Air Engine Cycle

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International Journal of Emerging Technology and Advanced Engineering

Website: www.ijetae.com (ISSN 2250-2459, ISO 9001:2008 Certified Journal, Volume 7, Issue 11, November 2017)

52

Compressed Air Engine Modified Four Stroke Single Cylinder

Petrol Engine Working on 2 Stroke Compressed Air Engine

Cycle

Sourabh Parikh

1

, Kshitij Sharma

2

, Abhishek Yawalkar

3

, Aakash Jangir

4 Medi-Caps Institute of Technology and Management

Abstract— Changes have always been a part of technology.

Since, the world is shifting towards renewable sources of energy in almost all the aspects of energy requirement, automobile is the most required one. Petroleum fuels like petrol and diesel are about be vanished in upcoming 45-50 years, thus compressed air can be a useful option as a fuel for driving the vehicles. A Compressed Air Engine is run by the Compressed Air that pushes piston to provide motion to the crankshaft by the help of pressure energy stored in it, which is released when the air expands. Compressed air also an eco-friendly fuel to the engine because no harmful emissions like CO2, SO2 or CO are observed since there is no combustion inside the cylinder and through the exhaust expanded natural air is emitted to the environment. While developing a Compressed Air Engine, control of compressed air parameters like temperature, pressure of the air, air released to the engine, pressure and volume of the air storage tank and emission control has to be mastered for the development of a safe and light weight Compressed Air Engine. Opting this technology will help in reducing global warming since temperature.

Keywords— Compressed Air, Engine, Environment, Energy, Fuels, Pressure, Technology

I. INTRODUCTION

Compressed Air Engines have been an immense part of automobile research since late 18th century

.

Louise Mekarski

(

a Polish researcher) was the first person to establish a Compressed Air Vehicle in 1870, which got its patent in 1872 in Paris. Then numerous innovations have been performed in this field by the various Scientists, Innovators and Automobile freaks. In 1984 Armando Regusci from Uruguay constructed a Four Wheeler with pneumatic engine which ran 100 km on single tank in year 1992. The best Air engine till date has been developed by a French Motor Vehicle company MDI and Its former Formula One engineer Guy Negre. The compressed-air -4-cylinder engine runs on Air and Gasoline, which claims to be eco-friendly because of its zero pollution cause.

This Air engine uses compressed air to push piston to provide motion to the crank shaft under 35 mph and at higher speed of 90 mph, the heated compressed air (by bio-fuels or gasoline) is used which expands before entering the engine. They claim to have a fuel efficiency of about 100 mpg. Another motor vehicle giant from Indian automobile market Tata Motor Vehicles is also working on the same project to industrialize the market with Compressed Air Cars in upcoming years.

Compared to battery Air Engines are more favorable because of high energy density and low cost of fuel. Out of all the concept vehicles that has been proposed running on solar energy, algae or biogas, Compressed Air Vehicles are the topic of great interest because of their easy-to-find-fuel and low cost.

II. COMPRESSED AIR ENGINE PRINCIPLE

A Compressed Air Engine is run by using compressed air which is stored in a high pressure tank (up to 300bar). This compressed air is supplied to inlet of the engine which works on 2 stroke cycle i.e. inlet and exhaust by the help of pressure regulating valves. This compressed air expands inside the cylinder and pushes the piston downwards. One manufacturer claims to have designed an engine which is 90% efficient.

The two strokes on which a Compressed Air Engine works are:

1.Intake cum power Stroke: Compressed air from the air tank enters the cylinder of the modified engine. This compressed air expands from a pressure P1 to P2 and exerts

a force on piston which draws piston from T.D.C. to B.D.C.

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International Journal of Emerging Technology and Advanced Engineering

53 Intake and Exhaust of a Compressed Air Engine

Theoretical P-V Diagram of a CAE

These graph has been studied and analysed and we reached to a conclusion that actual graph differs from theoretical because of several loses in the supply, expansion and exhaust of the compressed air gas. In the research we have found an actual graph which was quite addressing our analysis is shown below.

Actual P-V Diagram of a CAE

This is the actual graph made on the basis of analysis made. The process of a compressed air engine is not a closed cycle in practicality but rather can be considered as the one for further analysis.

III. ENGINE USED FOR CONVERSION TO CAE

For the proper implementation of our concept we have chosen an engine which would be able fulfill all the requirements like light in weight, easy to handle, proper lubricated and proper valve train and timing. Thus we analysed that Bajaj CT 100 is most feasible choice for our theoretical analysis whose specifications are:

Engine Specifications

Displacement 99.26 cc, Petrol engine No. of cylinders 1

Maximum Power 8.1 BHP @ 7500RPM Maximum Torque 8.05 NM @ 4500 RPM Compression ratio 9.5:1

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International Journal of Emerging Technology and Advanced Engineering

54 IV. DESIGN MODIFICATION AND CALCULATION

From the comparison of the conventional and air engine cycle we scrutinized that intervals for operation of inlet and outlet for both the engines are different. The valves must operate twice for air engine as compared to those of IC engines. Thus the cam for the retrofitted 2 stroke Compressed Air Engine must have double lift i.e. for 360o of rotation; cam must actuate the valve twice. For this requirement we have modified the cam shaft from 2 lobes on 90o angle to 180o as per the requirement as shown in the figure.

Movement of cam at different strokes in conventional 4-stroke single cylinder IC engine

Movement of cam in modified Compressed Air Engine (CAE)

This modified cam shaft helps in maintaining alternate opening and closing of inlet and exhaust valves. A comparing image between actual and modified cam shaft is given below.

Modified Compressed Air Engine

The figure shows a Compressed Air Engine in working condition after cam modification. The Inlet valve is opened in the first process and exhaust is closed, thus compressed air enters in to the cylinder. This compressed air expands and then inlet valve is closed and exhaust is opened to release the air.

In the theoretical analysis we concluded that CAE has three cycles for real, these are

 Constant pressure air intake

 Isentropic expansion of the compressed air

 Exhaust through outlet in slightly isochoric way Thus the calculation related to this can be made on the basis of this process cycle.

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International Journal of Emerging Technology and Advanced Engineering

55 Where N is engine RPM and T is torque.

B.P. = 3.937 KW

The required Indicated mean effective pressure will be based on this brake power which will provide the motion to the piston while running,

Here A is the bore area of the engine, L is the stroke length, n is N/2 = 2250 RPM (for 4-stroke engine), K=1 for single cylinder, by this formula the Bmep was found to be

10.1 bar.

For Imep, efficiency of the IC engine is assumed to be

80% and thus Imep was found to be 12.1 bar.

By this Indicated mean effective pressure it was analyzed that varying the pressure supply from 8 bar to 20 bar maximum torque can be achieved by the Compressed Air Engine.

This required supply of the pressure is fulfilled by a compressed air tank in which air is stored at high pressure (up to 300 bar) for the maximum storage. The variation in different parameters of compressed air as a function of compressed air pressure is shown by the graph.

The temperature of the compressed air reduces after adiabatic expansion. The efficiency of the CAE can be calculated by taking ratio of output power i.e. 2πNT/60 to input energy supplied to the engine i.e. _ΔP×Q, where _ΔP is

the change in pressure from inlet to outlet and Q is air flow under compressed conditions.

Since the input volume to the cylinder is V1 at pressure

P1 and pressure at the exhaust is Pexhaust. Thus efficiency is

calculated by the formula,

This would be the actual overall efficiency of the Compressed Air Engine.

V. ADVANTAGES AND DISADVANTAGES OF CAE

Advantages:

 It runs on electricity as compressor uses electricity to fill the tank but takes much lesser time to refilling than a battery takes to recharge.

 No transportation of compressed air is required like petroleum fuels thus reduces cost.

 Temperature generated inside the engine cylinder is very less as compared to IC engine thus low thermally sensitive material can be used to manufacture engine and also cooling system is not required.

 Exhaust can be installed easily because.

 The most important factor is price of refilling the tank of compressed air is much lesser as compared to petrol or diesel which makes it economic.

Disadvantages:

 In expansion stroke temperature of compressed air is reduces which causes the overall reduction in its thermal efficiency.

 It required air filling stations which are not common yet.

 The material of the air tanks must be carbon fibre or high speed steel because air is stored at very high pressure which can cause the bursting of tanks.

 Also for the low capacity tanks, air needs to filled frequently which causes loss in efficiency and reduces its reliability.

VI. CONCLUSION

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International Journal of Emerging Technology and Advanced Engineering

56 This paper lights the overall view on a Compressed Air Engine which is made by applying few modifications on a conventional IC engine and helps in understanding the working and process of different cycles in an air engine. Future developments can be made in designing a light weight vehicle for this kind of engines.

Acknowledgement

We would like to thank to Mr. Ram Bansal, professor at Medi-Caps Institute of Technology and Management for such a great help for this paper.

REFERENCES

[1] S.S.Verma, “AIR POWERED VEHICLES”,The Open Fuel & Energy Science Journal, 2008, Volume 1, pp.54-56.

[2] V.Ganeshan “Internal Combustion Engine-3rd Edition” chapter 1,2 and 7; Tata McGraw Hill Education Private Limited

[3] Guy and Cyril Negre- “Compressed Air: The Most Sustainable Energy Carrier for Community Vehicles”- Speech in front of assembly at Kultur gathered for “Fuel Cells World” Tuesday29th June ’2004.

[4] JP Yadav, Bharat Raj Singh,”Study and Fabrication Of Compressed Air Engine” S-JPSET : ISSn : 2229-7111,Vol. 2, Issue

[5] R.S.Khurmi, J.K. Gupta “A Text Book of Theory of Machines”, S.Chand.

[6] G.D. Rai, “NON-CONVENTIONAL ENERGY SOURCES”, Khanna Publishers, Fourth Edition, pp. 784-786.

[7] AIR POWERED ENGINE -Pramod Kumar J. ,International Journal of Mechanical Engineering and Technology (IJMET), Volume 7, Issue 2

[8] A.A.Keste, S. B. Vise, A. N. Adik, P. R. Borase“VEHICLE OPERATING ON COMPRESSED AIR BY INVERSION OF SLIDER CRANK MECHANISM”,IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE), pp. 50-54.

[9] Prof. B.S.Patel, Mr. R.S.Barot, Karan Shah, Pushpendrasharma; “AIR POWERED ENGINE” National conference on Recent Trends in Engineering & Technology-B.V.M. Engg. College, V.V.Nager, Gujarat, India, 13-14 May 2011.

[10] Haliburton, M.-S. Pure Energy Systems News, Engineair’s Ultra- Efficient Rotary Compressed-Air Motor, http://pesn.com/2006/05/11/9500269_Engineair_Compressed-Air_Motor/ (accessed June, 2008).

[11] [Online] Available: http://www.visionengineer.com [12] [Online] Available: http://www.tpup.com [13] SAE technical papers

[14] MDI (Moteur Development International). http://www.mdi.lu/english/2014%20english.php