experimental performance analysis of single cylinder · pdf file273 int. j. mech. eng. &...

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Int. J. Mech. Eng. & Rob. Res. 2014 Maneesh Kumar Dubey and Ravindra Randa, 2014

EXPERIMENTAL PERFORMANCE ANALYSIS OFSINGLE CYLINDER TWO STROKE PETROL ENGINE

USING GASOLINE AND LPGManeesh Kumar Dubey1* and Ravindra Randa1

*Corresponding Author: Maneesh Kumar Dubey,[email protected]

Present work shows a comparison of performance by using petrol and LPG at no load anddifferent load condition. Work was done in I.C. engine lab of mechanical engineering departmentUIT RGPV Bhopal and found that fuel consumption was minimum at 2250 RPM in case of bothfuels at no load and fuel consumption is minimum at 50% of the load in case of both fuels atloading condition. The experiment also shows that LPG gives maximum Brake Thermal Efficiency(BTE) at 50% of load and 31.32% less Fuel Consumption (FC) than petrol at load, low BrakeSpecific Fuel Consumption (BSFC), low Brake Specific Energy Consumption (BSEC) than petrolat the loading condition of the engine. The experiment also shows that LPG consumption atdifferent loading was also lower than the petrol and found minimum at 50% of the load and at noload condition, consumption of LPG is comparatively lower than the consumption of petrol. Forthis experiment minor modification was required wherever done to run the engine by LPG withoutany problem using some necessary attachments like attachment for lubrication, etc. This articlepresents the comparative testing results of a two stroke, single cylinder, air cooled, modified,petrol engine operating on petrol and LPG. This comparative performance analysis shows thatLPG is one of the better substitutes of petrol. Detailed comparative analysis of the engineperformance using petrol and LPG has been made by the graph plotted between variousparameters like Fuel Consumption (FC) and speed (RPM) for no load and for the different loadingconditions, graphs between load and Fuel Consumption (FC), load and Brake Specific FuelConsumption (BSFC), load and brake specific energy consumption (BSEC), and load and BrakeThermal Efficiency (BTE) and also done economic analysis. The present study shows that LPGis one of the better substitutes of petrol in terms of performance, consumption and cost.

Keywords: I.C. engine, Performance of I.C. engine, LPG and Petrol

INTRODUCTIONLiquefied Petroleum Gas (LPG) is one of themembers of natural gases and has been

ISSN 2278 – 0149 www.ijmerr.comVol. 3, No. 4, October 2014

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Int. J. Mech. Eng. & Rob. Res. 2014

1 University Institute of Technology, Rajiv Gandhi Proudyogiki Vishwavidyalya, Bhopal, India.

declared as the cleaner fuel. LPG isincreasingly chosen as the preferred burningfuel for all types of vehicles due to its

Research Paper

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advantageous fuel properties (Yusuf et al.,2005). A lot of researches have been done toprove that vehicles using LPG as the burningfuel shows no decreased in efficiencycompared to the conventional fuel operatingvehicles along with its advantage of reductionin emission gases from the exhaust of anengine (Mustafa and Gitano-Briggs, 2008).Besides that, LPG has the capability to reducethe noise from a running engine, helping toeffectively decrease noise pollution in urbanareas especially during the traffic congestionperiod (Seshaiah, 2010). There are currentlyover 4 million road vehicles using LPG incountries such as Italy, Holland, Japan, theUSA, and Australia due to the vast advantagesof LPG usage. Due of the abundance of LPGan important energy and environmentaladvantages, LPG has been promoted forusage in vehicles (Orhan Durgun and HakanBayraktar, 2005; and Seshaiah, 2010).However, the use of LPG requires that fueling,maintenance and storage facilities to beupgraded to a certain standard to ensureoperational safety of its (Semin Ibrahim et al.,2009). LPG is stored as a liquid in a separatesteel or composite vessel at the pressure of10 bars, although it can stand a pressure of20-30 bars (Kansu Wan and Kwankaomen,2010). LPG supply to the engine is controlledby a regulator or vaporizer, which converts theLPG to vapors. The vapors are fed to a mixerlocated near the intake manifold, where it ismetered and mixed with filtered air beforebeing drawn into the combustion chamberwhere it is burned to produce power, just likegasoline (Ceviz and Yuksel, 2006). The LPGenergy content (High Heating Value, HHV) is46.23 MJ/kg (Zuhadi Salhab, 2011). Thehigher octane rating and the low carbon and

oil contamination characteristics of LPG resultin a documented longer engine lifetime, up totwice that of the gasoline engines. Becausethe fuel mixture is fully gaseous, cold startproblems associated with liquid fuel areeliminated (Rosli Abu Bakar et al., 2002; andAlbela Pundkar et al., 2012). LPG hasrelatively high energy content per unit of mass;the range of LPG vehicles is equivalent to thatof petrol vehicles. Due to low maintenancecost, economic market price and environmentfriendly characteristics LPG are becoming apopular alternative for gasoline (Shinichi Gotoet al., 2000). LPG has the followingcharacteristics against gasoline (SyedYousufuddin and Syed Nawazish Mehdi, 2008;and Lawankar and Dhamade, 2013).

• Relative fuel consumption of LPG is abouteighty percent of that of gasoline by volume.

• LPG has a higher octane number, whichenables a higher compression ratio to beemployed and gives more thermalefficiency.

• Due to the gaseous nature of LPG fueldistribution between cylinders is improvedand smoother acceleration is achieved.

• LPG tank is heavier and requires morespace than a gasoline tank because LPGis stored under pressure.

• Engine life is increased for LPG operatedengine as cylinder bore wear is reduced &combustion chamber and spark Plugdeposits are reduced.

• Starting load on the battery for an LPGoperated engine is higher than gasolineengine due to higher ignition system Energyrequired.

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• LPG system requires more safety. In caseof leakage LPG has hazardous, it maycatch fire.

• LPG required more volume (15 to 20%more) as compared to gasoline.

Although LPG has a great deal ofadvantages, it has some limitations too, aslisted below (Thirumal Mamidi andSuryawanshi, 2012; and Deepak Bharadwajet al., 2012);

1. LPG is a non-renewable fossil fuel. If LPGuses faster than its generation, it will beginto deplete.

2. LPG is denser than air, in case of anyleakage it will accumulate in low lying areas,it may catch fire.

3. A bulky storage tank is needed to store LPG.Hence, the larger boot area is required toplace the storage tank in place. That alsoreduces the storage capacity.

4. It was revealed that there exist a number ofcountries with underdevelopedtechnologies for LPG distribution systemand therefore, limits its usage. LPG is onlyused in residential homes as heating andcooking gas.

5. The contents of propane in LPG are differentfor most countries. For instance, LPGcontains more than 90% propane in the UK,whereas in Italy the level can be as low as20% and 70% in India.

This fluctuation proves to be a barrier tostandardization of LPG vehicles aroundEurope and the rest of the world.

EXPERIMENTAL SETUPThe setup consists of single cylinder, twostroke, and air cooled petrol engine connectedto an electrical type dynamometer and loadingunit (rheostat type) for loading. It is providedwith necessary instruments for measurementsof various parameters. The setup has stand-alone consisting of air box, fuel tank,manometer, fuel measuring unit, etc. Presentstudy performs in thermal engineering lab of

Characteristics Gasoline Propane

Chemical formula C8H18 C3H8

Boiling point (°C) 30-225 -44

Molecular weight (kg/Kmol) 114.2 44.1

Density at 15 °C kg/l 0.705 0.507

Auto ignition temperature (°C) 285 480

Octane number (RON) 91.8 112

Octane number (MON) 89 99.5

Stoichiometric air fuel ratio(kg/kg) 14.7 15.6

Upper Flammability limits in air(% vol) 7.6 74.5

Lower Flammability limits in air(% vol) 1.3 4.1

Lower calorific value (KJ/kg) 44000 46500

Higher calorific value (KJ/Kg) 46530 50150

Table 1: Properties of Gasoline and LPG

Source: Bayraktar and Durgun (2003) and ETSAP (2010)

Figure 1: Experimental Setup at UIT RGPVBhopal

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UIT RGPV Bhopal (M.P.), set up image shownin Figure 1.

The main aim of this experiment is toinvestigate the effect on performance ofgasoline and LPG in single cylinder, two stroke,and petrol engine. Performance investigationof LPG and gasoline were evaluated in a twostroke, single cylinder spark ignition engineoperated at different-different speed at no loadcondition and at constant speed in varying loadcondition. Engine tests were carried out atdifferent speed (rpm) at no load and findspeed (RPM) at which minimum fuelconsumption takes place and at loadingcondition engine test was carried out atconstant speed (2250 rpm) for fuelconsumption in case of gasoline is used as afuel. The same test is carried out for engine byusing LPG as a fuel with few additionalcomponents and modification, require for safeoperation of two stroke spark ignition engineoperated with LPG. Technical specifications

of the test engine are given in Table 2 andsimplified block diagram of the experimentalsetup in Figure 2.

Parameters Details

Name of manufacturer Brand new assembleengine Bajaj make

Speed 800-6000 RPM

No of Stroke Two stroke

Fuel used Petrol

No of cylinder Single

Type of cooling Air cooled

Type of starting Kick start

Fuel intake measurement Calibrated burette

Dynamometer Electrical type (2 KW)

Loading system Rheostat loading

Air intake measurement Orifice and watermanometer

Exhaust gas calorimeter Water cooled type

Table 2: Detailed Specificationsof the Test Engine Setup

Figure 2: Block Diagram of ExperimentalSetup

Modified Experimental SetupA number of problems encountered in usingLPG directly as fuel in two stroke petrol engine.Due To problems encountered in starting ofthe engine, lubrication problem, etc. variousadditional components like arrangement forlubrication, and few modifications are requirefor engine operation. Following additionalcomponents require for LPG operation are: (i)Gas vaporizer, (ii) Pressure regulator, (iii) LPGtank, (iv) Weighing Machine (WM), (v) Mixerand Tee, (vi) Pipe for LPG, lubricant andvacuum, (vii) Lubricant Bottle (LB).

Gas Vaporizer: It is the most important partof the modified experimental set up withoutvaporizer engine cannot be operated throughLPG fuel. A vaporizer is a device thattransforms liquid phase LPG to vapor phaseLPG. LPG Vaporizers are used for vaporizingliquid fuel gases (i.e., propane, butane, naturalgas) or even other gases for use in variousheating or other processes. In the first stageLPG is firstly vaporized and successively

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reduced in pressure. The second stagechamber is very sensible to the vacuumpressure. The vacuum pressure causes theflow of LPG to the engine to increase ordecrease depending on the pressuredifference. Any pressure difference istransferred to the second stage chamber andthe membrane will allows for a greater flow ofgas to enter the engine.

Pressure Regulator: A pressure regulator isa valve that controls the flow of a liquid gas atcertain pressure. Gas pressure regulators areused to regulate gas flow and are not used formeasuring flow rates. A pressure regulator’sprimary function is to match the flow of gasthrough the regulator to the demand for gasplaced upon the system. If the load flowdecreases, then the regulator flow mustdecrease also. If the load flow increases, thenthe regulator flow must increase.

LPG Tank: Available in 18 different approvedsizes to suit most vehicles in India. The twovariant available are called; Cylindrical typeand toroidal type. The tank also has differentcapacity variants. LPG cylinder of 2 kg capacityis used in this experiment.

Weighing Machine: Weighing scales areused in many industrial and commercialapplications. In present experiment electronic(digital type) weighing machine is used forcalculating the consumption quantity of LPG,which have least count of one gram andmaximum capacity of weighing machine is 10Kg. Electronic type weighing machines havean advantage over mechanical balances dueto the following reasons; (i) Compactness, (ii)Good accuracy and Ease of operation, (iii)Ruggedness and reliability.

Mixer and Tee: The mixer has an extremelyimportance. The right air- fuel ratio dependson the mixer and this is the reason for theexistence of mixer. The mixer for vehiclesequipped with engine between carburetor andengine. Mixer are metallic and non metallic.We have use metallic mixer for experiment inthis test. T-shape metallic valve is used tocontrol the supply of lubricating oil to the engine.It is fitted near the mixer in the lubricant supplypipe. Arrangement for controlling the quantityof lubricating oil is also given with tee.

Pipe for LPG, Lubricant and Vacuum: Pipeuse to supply LPG, from LPG tank to vaporizeris called LPG or fuel pipe. It is larger indiameter than lubricant and vacuum pipeshown. LPG pipe should have better qualitybecause continuous supply of LPG candamage the pipe when it is use very long time.Pipe through which lubricant is supplied to theengine is called lubricant pipe, it connectlubricant bottle with mixer through tee. It istransparent in colour. Pipe which is providedfor air is called air or vacuum pipe, its one endis connected to the mixer and other isconnected to vaporizer.

Lubricant Bottle: In two stroke petrol enginelubricating oil is mixed with petrol in petrol tankbut when engine is operated with LPGattachment for lubrication of engine is requirewhich supply lubricant to the engine directly.Special bottle for lubricant is attached to theengine for proper lubrication when engine isoperated with LPG.

RESULTS AND DISCUSSIONTwo stroke stationary petrol engine wasoperated under different speed at no load byusing petrol and LPG respectively and find the

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speed (rpm) at which minimum fuelconsumption takes place in both cases whenengine is operated with LPG and petrol andplotting the graph between speed (rpm) andFuel Consumption (FC) for both LPG andpetrol fuel. With the help of graph compare andinvestigate the fuel consumption for both of thefuel. By investigating the graph we findminimum fuel consumption takes place at2250 rpm for both of the fuel. Again enginewas operated at different loading condition andat steady state speed (2500 rpm) anddetermine various performance parameter likeFuel Consumption (FC), Brake Specific FuelConsumption (BSFC), Brake Specific EnergyConsumption (BSEC), and brake thermalefficiency. By plotting graphs between load andfuel consumption, load and BSFC, load andBSEC, and load and brake thermal efficiencyand then comparing the performance for LPGand petrol fuel, we find that LPG becomesbetter substitute of petrol fuel because cast ofcommercial LPG cast is less than the cast ofpetrol fuel.

The results obtained by Performing theexperiment on the Engine by using gasolineand LPG respectively at different-differentspeed and different-different loadingconditions are discussed. In the presentinvestigation the fuel consumption (when petrolis used) is increase with the speed (RPM). Itbecomes minimum at 2250 rpm and thenincrease with speed up to maximum speedlimit of the engine.

When LPG is used as a fuel, fuelconsumption follow same pattern as in caseof gasoline, in this case minimum consumptionof LPG takes place also at 2250 rpm. In thiscase fuel consumption increases with the

speed (RPM) and minimum at 2250 rpm thenincrease up to maximum speed limit, whenengine is running at no load. Variation of FuelConsumption (FC) with speed (RPM) is shownin the graph (Figure 3).

When engine is operated at loadingkeeping speed (RPM) constant andinvestigate the consumption of fuel when loadis increased. For loading condition of engineby using relation we can determine FuelConsumption (FC), Brake sSpecific FuelConsumption (BSFC), Brake Specific EnergyConsumption (BSEC) and brake thermalefficiency. And plot graphs between load andvarious parameters (FC, BSFC, BSEC, BTE)

Figure 3: Graph Between FuelConsumption and Speed (RPM)

at No Load Condition

Figure 4: Graph Between FuelConsumption (FC) and Load

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and by studying the graphs (Figures 4 to 7)we can compare performance of the SI engineoperated with LPG and petrol and findoperation of engine is better, efficient and

economical by LPG fuel then petrol fuel.Consumption of lubricating oil is also less incase of LPG fuel operation that makesoperation of engine by LPG is moreeconomical.

CONCLUSIONOn the basis of experimental results followingconclusion can be drawn;

• Consumption of LPG fuel is slightly lowerthan the petrol at no load condition. LPGconsumption is16.92% less than the petrolconsumption at 2250 RPM at whichminimum consumption of fuel takes placefor both of the fuel.

• LPG consumption is also low compare topetrol when engine is operated at loadingcondition. Fuel consumption decreaseswith load increase and minimum when loadon engine is 50% of the full load for bothfuels than fuel consumption again increaseswith load. After 75% of loading fuelconsumption is nearly same for both of fuel.At 50% of loading LPG consumption is31.32% less than the petrol consumption.

• Brake Specific Fuel Consumption (BSFC)and Brake Specific Energy Consumption(BSEC) is comparatively lower for LPG fuel.BSFC and BSEC for both of the fuel areapproximately same after 64% of theloading on the engine. Before 64% of theloading on engine, BSFC and BSEC bothare comparatively low for LPG fuel.

• Brake thermal efficiency for LPG fuel ismore than the petrol fuel at same load. Incase of LPG fuel BTE is maximum at 50%of the loading and in case of petrol fuel BTEis maximum at 75% of loading. In low

Figure 5: Graph Between Brake SpecificFuel Consumption (BSFC) and Speed

(RPM)

Figure 6: Graph Between Brake SpecificEnergy Consumption (BSEC) and Load

Figure 7: Graph Between Brake ThermalEfficiency and Load

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loading condition BTE is lower and itincreases with load up to a certain limit thestart to decrease with load. BTE of enginewhen LPG is used as a fuel is higher thanthe petrol fuel.

• Results obtained after experiment indicatethat LPG characteristics are very close andsuperior to petrol. It can be one of the betteralternate fuels for petrol engine and can beused as a one of the alternate fuel for petrolengine, which is cheap and satisfactoryperformance.

• From economy point of view LPG fuel iscomparatively less in cast (auto gas or LPG51.52 Rs./liter.) than the petrol (75.08 Rs./liter.) and in case of petrol fuel lubricatingoil consumption is more than the LPG fueloperation. This means that operation ofengine by LPG is more economical then thepetrol fuel operation.

ACKNOWLEDGMENTThe authors wish to acknowledge the supportrendered by University Institute of Technology,Bhopal in preparation of this manuscript.

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