Engine Performance And Exhaust

Published Date: 02 Nov 2017

CHAPTER 2

Hakan Bayraktar observed the effects of ethanol addition to gasoline on an SI

engine performance and exhaust

emissions, experimentally and

theoretically.

Experimental applications have been carried out with the blends containing 1.5, 3, 4.5, 6,

7.5, 9, 10.5 and 12 vol% ethanol. Results obtained from both theoretical and experimental

studies are compared graphically. Experimental results have shown that among the

various blends, the blend of 7.5% ethanol was the most suitable one from the engine

performance and CO emissions points of view. However, theoretical comparisons have

shown that the blend containing 16.5% ethanol was the most suited blend for SI engines

[1].

M. Bahattin Celik studied experimental determination of suitable ethanol–

gasoline blend rate at high compression ratio for gasoline engine. In this study, ethanol

was used as fuel at high compression ratio to improve performance and to reduce

emissions in a small gasoline engine with low efficiency. Initially, the engine whose

compression ratio was 6/1 was tested with gasoline, E25 (75% gasoline + 25% ethanol),

E50, E75 and E100 fuels at a constant load and speed. It was determined from the

experimental results that the most suitable fuel in terms of performance and emissions

was E50. Then, the compression ratio was raised from 6/1 to 10/1. The experimental

results showed that engine power increased by about 29% when running with E50 fuel

compared to the running with E0 fuel. Moreover, the specific fuel consumption, and CO,

CO2, HC and NOx emissions were reduced by about 3%, 53%, 10%, 12% and 19%,

respectively [2].

G. Najafi, et. al. did research on Performance and exhaust emissions of a gasoline

engine with ethanol blended gasoline fuels using artificial neural network. The purpose of

this study is to experimentally analyse the performance and the pollutant emissions of a

four-stroke SI engine operating on ethanol–gasoline blends of 0%, 5%, 10%, 15% and

20% with the aid of artificial neural network (ANN). The experimental results revealed

that using ethanol–gasoline blended fuels increased the power and torque output of the

engine marginally. An ANN model was developed to predict a correlation between brake

1

power, torque, brake specific fuel consumption, brake thermal efficiency, volumetric

efficiency and emission components using different gasoline–ethanol blends and speeds

as inputs data. This study demonstrates that ANN approach can be used to accurately

predict the SI engine performance and emissions [3].

Alan C. Hansen et. al in their review paper presented a review on the properties

and specifications of ethanol blended with diesel fuel. Special emphasis is placed on the

factors critical to the potential commercial use of these blends. These factors include

blend properties such as stability, viscosity and lubricity, safety and materials

compatibility. The effect of the fuel on engine performance, durability and emissions are

also considered. The formulation of additives to correct certain key properties and

maintain blend stability is suggested as a critical factor in ensuring fuel compatibility with

engines. However, maintaining vehicle safety with these blends may entail fuel tank

modifications [4].

Eliana Weber de Menezes et. al proposed an azeotropic TBE (ethyl tert-butyl

ether)/ethanol mixture as a possible oxygenated additive for the formulation of eurosuper-

type gasoline. Formulations containing this additive offer advantages over ethanol (low

volatility and low solubility in water) and ETBE (higher octane number and lower

production cost). Gasoline with azeotropic additives show lower Reid vapor pressures

(RVPs) than gasoline formulated with ethanol, and therefore low levels of volatile

organic compounds, similarly to highly pure ETBE. The use of the azeotropic mixture

containing ethanol (renewable, deriving from biomass) and ETBE (produced from

ethanol and isobutene) in its formulation is environmentally attractive in industrialized

countries due to the need to reduce carbon dioxide emissions [5].

Hu¨seyin Serdar Yu¨cesu, et. al in this study, explained the effect of

compression ratio on engine performance and exhaust emissions at stoichiometric air/fuel

ratio, full load and minimum advanced timing for the best torque MBT in a single

cylinder, four stroke, with variable compression ratio and spark ignition engine. In their

study, test fuels were prepared using 99.9% pure ethanol and gasoline blended with the

volumetric ratios of 0-30% (E0, E5, E10, E20 and E30). It is reported that, this arose

from the original fuel injection system strategies which prepare rich fuel mixtures.

Therefore, the leaning effect of ethanol to increase the air fuel equivalence ratio (k) to

2

higher value, and make the burning closer to be stoichiometric. As a result the better

combustion can be achieved and higher torque output can be acquired [6].

Jincheng Huang, et. al., did an experimental investigation on the application of

the blends of ethanol with diesel to a diesel engine. The test results show that it is feasible

and applicable for the blends with n-butanol to replace pure diesel as the fuel for diesel

engine; the thermal efficiencies of the engine fueled by the blends were comparable with

that fueled by diesel, with some increase of fuel consumptions, which is due to the lower

heating value of ethanol. The characteristics of the emissions were also studied [7].

Mustafa Koç, et. al. investigated experimentally, the effects of unleaded gasoline

(E0) and unleaded gasoline-ethanol blends (E50 and E85) on engine performance and

pollutant emissions in a single cylinder four-stroke spark-ignition engine at two

compression ratios (10:1 and 11:1). The engine speed was changed from 1500 to 5000

rpm at wide open throttle (WOT). The results of the engine test showed that ethanol

addition to unleaded gasoline increase the engine torque, power and fuel consumption and

reduce carbon monoxide (CO), nitrogen oxides (NOx) and hydrocarbon (HC) emissions.

It was also found that ethanol-gasoline blends allow increasing compression ratio (CR)

without knock occurrence [8].

Perihan Sekmen, Yakup Sekmen formulated mathematical model to find the

performance of an engine whose basic design parameters are known. This can be

predicted with the assistance of simulation programs into the less time, cost and near

value of actual. However, inadequate areas of the current model can guide future research

because the effects of design variables on engine performance can be determined before.

In their study, thermodynamic cycle and performance analyses were simulated for various

engine speeds (1800, 2400 ve 3600 1/min) and various excess air coefficients (EAC)

(0.95-1.05) to crank shaft angle (CA) with 1 degree increment at full load and 8:1

constant compression ratio (CR) of a SI engine with four stroke, single cylinder and

natural aspirated. Brake mean effective pressure, power, thermal efficiency, specific fuel

consumption (sfc), etc engine performance parameters were calculated; the values of peak

cylinder pressures and temperatures and positions of them were determined by the present

program. Variations of these parameters with crank angle, engine speed and excess air

coefficient were presented graphically. The calculated results show good agreement with

3

literature. Simulation program was used to set for varies load, compression ratios, and

engine sizes [9].

M. Al- Hasan investigated the effect of using unleaded gasoline–ethanol blends

on SI engine performance and exhaust emission. A four stroke, four cylinder SI engine

(type TOYOTA, TERCEL-3A) was used for conducting this study. Performance tests

were conducted for equivalence air–fuel ratio, fuel consumption, volumetric efficiency,

brake thermal efficiency, brake power, engine torque and brake specific fuel

consumption, while exhaust emissions were analyzed for carbon monoxide (CO), carbon

dioxide (CO2) and unburned hydrocarbons (HC), using unleaded gasoline–ethanol blends

with different percentages of fuel at three-fourth throttle opening position and variable

engine speed ranging from 1000 to 4000 rpm. The results showed that blending unleaded

gasoline with ethanol increases the brake power, torque, volumetric and brake thermal

efficiencies and fuel consumption, while it decreases the brake specific fuel consumption

and equivalence air–fuel ratio. The CO and HC emissions concentrations in the engine

exhaust decrease, while the CO2 concentration increases. The 20 vol.% ethanol in fuel

blend gave the best results for all measured parameters at all engine speeds [10].

Sundeep Ramachandran presented a thermodynamic model for the simulation of

a spark ignition engine running on alternate hydrocarbon fuel. This paper aims to develop

a simple, fast and accurate engine simulation model without the need for a great deal of

computational power or knowledge of precise engine geometrical data. The model is

based on the classical two-zone approach, wherein parameters like heat transfer from the

cylinder, blowby energy loss and heat release rate are also considered. Curve-fit

coefficients are then employed to simulate air and fuel data along with frozen

composition and practical chemical equilibrium routines [11].

M.A. Ceviz , F. Yuksel presented a paper to find out the ways to reduce cyclic

variability. A small amount of cyclic variability (slow burns) can produce undesirable

engine vibrations. On the other hand, a larger amount of cyclic variability (incomplete

burns) leads to an increase in hydrocarbon consumption and emissions. This paper

investigates the effects of using ethanol–unleaded gasoline blends on cyclic variability

and emissions in a spark-ignited engine. Results of this study showed that using ethanol–

unleaded gasoline blends as a fuel decreased the coefficient of variation in indicated mean

4

effective pressure, and CO and HC emission concentrations, while increased CO2

concentration up to 10vol.% ethanol in fuel blend. On the other hand, after this level of

blend a reverse effect was observed on the parameters aforementioned. The 10vol.%

ethanol in fuel blend gave the best results [12].

Wei-Dong Hsieh, Rong-Hong Chen, Tsung-Lin Wu, Ta-Hui Lin did the study

to experimentally investigate the engine performance and pollutant emission of a

commercial SI engine using ethanol–gasoline blended fuels with various blended rates

(0%, 5%, 10%, 20%, 30%). Fuel properties of ethanol–gasoline blended fuels were first

examined by the standard ASTM methods. Results showed that with increasing the

ethanol content, the heating value of the blended fuels is decreased, while the octane

number of the blended fuels increases. It was also found that with increasing the ethanol

content, the Reid vapor pressure of the blended fuels initially increases to a maximum at

10% ethanol addition, and then decreases. Results of the engine test indicated that using

ethanol–gasoline blended fuels, torque output and fuel consumption of the engine slightly

increase; CO and HC emissions decrease dramatically as a result of the leaning effect

caused by the ethanol addition; and CO2 emission increases because of the improved

combustion. Finally, it was noted that NOx emission depends on the engine operating

condition rather than the ethanol content [13].

K Venkateswarlu, M Ramesh, K Veladri tested the effect of methanol-gasoline

blends. Their work described the improved engine efficiency with higher compression

ratios by using methanol-gasoline blends (mixing-methanol in small proportions with

gasoline) as methanol had high anti-knock characteristics. Existing engines were not

generally suitable to operate on higher contents of methanol, as the engine needs major

modifications. The present work considered methanol blended fuels M-10, M-20 and M-

30 (number denotes the percentage of methanol in gasoline) as alternative fuel for four

stroke variable compression ratio spark ignition (S I) engine. Experimental results

demonstrated that an increase of 48% in brake thermal efficiency had been observed

compared to gasoline operation. An increase of 8% in volumetric efficiency was found

and a reduction of 24% in BSFC was observed [14].

Ivan Arsie, Cesare Pianese, Rizzo presented a thermodynamic model

for

Prediction of Performance and Emission in a Spark Ignition Engine. This model is a part

5

of intergratged system of models of structure developed for optimal study and optimal

design of engine control strategies [15].

Martyn Roberts studied benefits and challenges of VCR Engine. Potential

benefits of Variable Compression Ratio (VCR) spark ignition engines were presented

based on an examination of the relationship between Compression Ratio, BMEP and

spark advance at light load and full load. Alternative methods of implementing VCR are

illustrated and critically examined. System control strategies are presented. Fuel economy

benefits attainable from other technologies such as cylinder deactivation, camless valve

operation and GDI are shown to be inferior to the use of downsized boosted engines [16].

Antoni Jankowski, Alexander Sandel did the research on emission reuction of

engines using biofuels. Introduction of biofuels to fueling of automotive engines is the

one method to decrease emissions of greenhouse gases. The CO2 from biofuels, is emitted

during combustion and absorbed during growth of tree end plants. The results of biofuels

applying in viewpoint of exhaust emissions are presented in this paper. The most

promising of biofuels for fueling of internal combustion engines are esters of vegetable

oils and ethanol. Ethanol can be used for fueling spark ignition engines and compression

ignition engines but vegetable oil esters can be used in compression ignition engines only.

The paper describes an increase of CO2 content in atmospheric air and advantages and

concerns from using of biofuels [17].

Adnan Berber, Mustafa Tinkir, S. Sinan Gültekin and Ismet Çelikten used

different modeling techniques for prediction of diesel engine characteristics. In thier

study, the characteristics of a four-stroke internal combustion diesel engine have been

investigated by means of artificial neural networks (ANNs) and adaptive neuro-fuzzy

inference system (ANFIS) modelling techniques, using injection pressure, engine speed

and torque. The proposed ANNs and ANFIS models are composed of the results of

implemented measurements. ANNs model of the diesel engine has two subsystem. The

first subsystem has two outputs (BMEP, FF) and the second subsystem has single output

as specific fuel consumption (SFC). The performance of ANNs and ANFIS models are

compared with each other in same figures for same experimental data. The results of

modeling techniques of a four-stroke internal combustion diesel engine are observed to be

very close with the experimental results [18].

6

Mayur D. Bawankure, Prashant A. Potekar, Bhushan A.Nandane, Vivek R.

Gandhewar, found the methods to predict the performance evaluation of CI engine using

fuel blends. A comprehensive study on the ethanol as an alternative fuel with Palm

Stearin Methyl-Ester oil as additive has been carried out. A four stroke single cylinder

water cooled variable compression ratio diesel engine was used to study engine power,

torque, break specific fuel consumption, break thermal efficiency and exhaust gas

temperature with the diesel – ethanol blend with addition of small amount of

biodiesel(PSME). The experiment result shows that the brake thermal efficiency of the

engine increases for B40 blend for medium load capacity. It also shows that the exhaust

gas temperature for B10 ratio is near the diesel fuel. Brake specific fuel consumption of

all ethanol Methyl-ester, diesel blends are lower compared with diesel at full load [19].

Alvydas Pikūnas, Saugirdas Pukalskas, Juozas Grabys found out the effect of

gasoline ethanol blend on engine performance.

The purpose of their study was to

investigate experimentally and compare the engine performance and pollutant emission of

a SI engine using ethanol–gasoline blended fuel and pure gasoline. The results showed

that when ethanol is added, the heating value of the blended fuel decreases, while the

octane number of the blended fuel increases. The results of the engine test indicated that

when ethanol–gasoline blended fuel is used, the engine power and specific fuel

consumption of the engine slightly increase; CO emission decreases dramatically as a

result of the leaning effect caused by the ethanol addition; HC emission decreases in some

engine working conditions; and CO2 emission increases because of the improved

combustion [20].

Wei-Dong Hsieha, Rong-Hong Chenb, Tsung-Lin Wub, Ta-Hui Lina did the

research on effect of blending gasoline ethanol on engine performance and emissions of

the engine. The purpose of the study was to experimentally investigate the engine

performance and pollutant emission of a commercial SI engine using ethanol–gasoline

blended fuels with various blended rates (0%, 5%, 10%, 20%, 30%). Results showed that

with increasing the ethanol content, the heating value of the blended fuels is decreased,

while the octane number of the blended fuels increases. Results of the engine test

indicated that using ethanol–gasoline blended fuels, torque output and fuel consumption

of the engine slightly increase; CO and HC emissions decrease dramatically as a result of

7

the leaning effect caused by the ethanol addition; and CO2 emission increases because of

the improved combustion [21].

Wayne Moore, Matthew Foster and Kevin Hoyer presented the techniques for

engine performance enhancement using ethanol fuel blends.

In this paper results are

presented from a flexible fuel engine capable of operating with blends from E0-E85. The

increased geometric compression ratio, (from 9.2 to 11.85) can be reduced to a lower

effective compression ratio using advanced valvetrain operating on an Early Intake Valve

Closing (EIVC) or Late Intake Valve Closing (LIVC) strategy. DICP with a high

authority intake phaser is used to enable compression ratio management. The advanced

valve train also provides significantly reduced throttling losses by efficient control of

intake air and residuals. Increased ethanol blends provide improvements in power density

due to knock resistance [22].

N. Seshaiah studied the effect of biofuel on performance of engine and its

emissions. In their research work, the variable compression ratio spark ignition engine

designed to run on gasoline has been tested with pure gasoline, LPG (Isobutene), and

gasoline blended with ethanol 10%, 15%, 25% and 35% by volume. Also, the gasoline

mixed with kerosene at 15%, 25% and 35% by volume without any engine modifications

has been tested and presented the result. Brake thermal and volumetric efficiency

variation with brake load is compared and presented. CO and CO2 emissions have been

also compared for all tested fuels [23].

Dr. A. R. A. Habbo, Raad A. Khalil, Hassan S. Hammoodi presented a paper

on Effect of Magnetizing the Fuel on the Performance of an S.I. Engine. The aim of this

study was to investigate the effect of the magnetized fuel on the performance of spark

ignition engine. The engine performance was observed by examining the engine brake

power (BP) , thermal efficiency , specific fuel consumption (SFC) and exhaust emissions

.The fuel is subjected to a magnetic field which is placed to fuel supply line to magnetize

the fuel before admitted to the engine cylinder.

The results show a significant

improvements in engine performance, the thermal efficiency and engine power increased

by (4 %) and (3.3 %) respectively when a magnetic coil of 1000 Gauss is used, and a

reduction in the specific fuel consumption by (12.8 %) was achieved [24].

8

Shailesh Kumar Trivedi, Abid Haleem in their paper computed the available

and unavailable energy using first and second law of thermodynamics for wet ethanol

operated homogeneous charge compression ignition (HCCI) engine for cogeneration

application. This paper also presents the evaluation of effect of ambient temperature,

turbocharger compressor pressure ratio and effectiveness of regenerator on the first and

second law efficiencies of the system. The numerical computational analysis of the

system indicates that the first and second law efficiencies are decreasing with ambient

temperature as the increase in ambient temperature increases the charge intake

temperature which leads to reduced work output and it finally results in reduced

efficiencies [25].

Peerawat Saisirirat, Anthony Dubreuil, Fabrice

Foucher,

Christine

Mounaïm-Rousselle, Somchai Chanchaona studied of HCCI Combustion for

Hydrocarbon-Ethanol Mixture.. The heat release rate-time history from cylinder pressure

data analysing shows the interesting characteristics of each fuel depends on its kinetics

mechanism. This study is concentrated on the HCCI combustion for n-heptane/ethanol

mixture.. The effects of ethanol fraction to combustion characteristics were explained

with this approach. The results show why the cool flame approaches to the main heat

release when ethanol fraction is increased. In the future work, the planar laser induced

fluorescence (PLIF) technique will be applied to the experimental work to fulfil the

understanding of HCCI combustion [26].

Rodrigo C. Costa, José R. Sodré compared the performance and emissions from

a production 1.0-l, eight-valve, and four-stroke engine fuelled by hydrous ethanol (6.8%

water content in ethanol) or 78% gasoline-22% ethanol blend. The results showed that

torque and BMEP were higher when the gasoline-ethanol blend was used as fuel on low

engine speeds. On the other hand, for high engine speeds, higher torque and BMEP were

achieved when hydrous ethanol fuel was used. Hydrous ethanol produced higher thermal

efficiency and higher SFC than the gasoline-ethanol blend throughout all the engine speed

range studied. With regard to exhaust emissions hydrous ethanol reduced CO and HC, but

increased CO2 and NOX levels [27].

Er. Milind S Patil, Dr. R. S. Jahagirdar, Er. Eknath R Deore conducted

research on 3.75 kW diesel engine AV1 Single Cylinder water cooled, Kirloskar Make to

9

test blends of diesel with kerosene and Ethanol. This paper presents a study report on the

performance of IC engine using blends of kerosene and ethanol with diesel with various

blending ratio. Parameters like speed of engine, fuel consumption and torque were

measured at different loads for pure diesel and various combination of dual fuel. Break

Power, BSFC, BTE and heat balance were calculated. Paper represents the test results for

blends 5% to 20% [28].

C. Anada Srinivasan and C.G.Saravanan in their study, the effects of ethanol

and unleaded gasoline with 1, 4 Dioxan blends on multi-cylinder SI engine were

investigated. The test fuels were prepared using 99.9% pure ethanol and gasoline with 1,4

Dioxan blend, in the ratio of 50+5 1,4 Dioxan, E 60+101,4 Dioxan, the rest gasoline. In

this work, the performance and emission tests were conducted in a multi-cylinder petrol

engine. The experimental results reveal the increase in brake thermal efficiency for the

blends when compared to that of sole fuel. In this investigation, the emission tests are

made with the help of AVL Di Gas analyzer, in which CO, CO2, HC, NOX are

appreciably reduced and O2 is increased for all the blends when compared to sole fuel

[29].

S. Y. Liao, D. M. Jiang, Q. Cheng, Z. H. Huang, and Q. Wei conducted

experimental study in a closed combustion chamber to investigate combustion

characteristics of ethanol-gasoline blends at low temperature, which is related to the cold-

start operation of engines fueled with ethanol-gasoline. The result shows that, for an

ethanol-gasoline engine, it must not be overfueled to realize a reliable cold start, as is the

case for a gasoline engine at the same temperature, especially at a temperature range

around ethanol’s boiling point, because ethanol addition into gasoline results in the

improvement of blend evaporation. It is shown that, for ethanol-gasoline blends with

ethanol content below 30%, the suitable fuel-air ratio to realize fast flame propagation is

about 1.3 [30].

Suri Rajan and Fariborz F. Saniee investigated the miscibility characteristics of

hydrated ethanol with gasoline as a means of reducing the cost of ethanol/gasoline blends

for use as a spark ignition engine fuel. For a given percentage of water in the ethanol, the

experimental data shows that a limited volume of gasoline can be added to form a stable

mixture. Engine experiments indicate that, at normal ambient temperatures, a

10

water/ethanol/gasoline mixture containing up to 6 vol% of water in the ethanol constitutes

a desirable motor fuel with power characteristics similar to those of the base gasoline

[31].

Wei-Dong Hsieha, Rong-Hong Chenb, Tsung-Lin Wub, Ta-Hui Lina

conducted the study to experimentally investigate the engine performance and pollutant

emission of a commercial SI engine using ethanol–gasoline blended fuels with various

blended rates (0%, 5%, 10%, 20%, 30%). Results showed that with increasing the ethanol

content, the heating value of the blended fuels is decreased, while the octane number of

the blended fuels increases. It was also found that with increasing the ethanol content, the

Reid vapor pressure of the blended fuels initially increases to a maximum at 10% ethanol

addition, and then decreases. Finally, it was noted that NOx emission depends on the

engine operating condition rather than the ethanol content [32].

Hsi-Hsien Yang , Ta-Chuan Liu , Chia-Feng Chang , Eva Lee investigated the

emission characteristics of regulated air pollutants and carbonyls from motorcycles using

gasoline blended with 3% ethanol (E3) and gasoline (E0) in this study. Nine motorcycles

were operated on a chassis dynamometer and driven according to the ECE driving cycle

for air pollutant measurements. In addition, durability testing was performed on two

brand-new motorcycles of the same model, using E3 in one and E0 in the other, to assess

the effects of E3 usage on motorcycle emissions. The results show that average emission

factors of CO and THC decreased by 20.0% and 5.27%, respectively using E3 fuel.

However, NO and CO emission increased by 5.22% and 2.57% [33].

John M. E. Storey, Teresa L. Barone, Kevin M. Norman, and Samuel A.

Lewis, Sr did the research t find the effects of gasoline ethanol blend on direct injection

SI engine. In addition to changes in gasoline engine technology, fuel composition may

increase in ethanol content beyond the 10% allowed by current law due to the Renewable

Fuels. In this study, authors presented the results of an emissions analysis of a U.S.-legal

stoichiometric, turbocharged DISI vehicle, operating on ethanol blends, with an emphasis on

detailed particulate matter (PM) characterization [34].

V. Arul Mozhi Selvan, R. B. Anand and M. Udayakumar carried out an

experimental investigation to establish the performance and emission characteristics of a

11

compression ignition engine while using cerium oxide nanoparticles as additive in neat

diesel and diesel-biodiesel-ethanol blends. In the first phase of the experiments, stability

of neat diesel and diesel-biodiesel-ethanol fuel blends with the addition of cerium oxide

nanoparticles are analyzed. The tests revealed that cerium oxide nanoparticles can be used

as additive in diesel and diesel-biodiesel-ethanol blend to improve complete combustion

of the fuel and reduce the exhaust emissions significantly [35].

Radivoje Peši

, Snežana Petkovi

, Golec Kazimierz, Emil Hnatko, Stevan

Veinovi

conducted a research on Biofules and delusions of the Kyoto Protocol. The next

stage of power train and fuel strategy involves using new high economy combustion

engines that can be run with partially renewable fuels and used worldwide. This paper

analyses delusions of the "Kyoto protocol" and presents the results of our own research of

cetane characteristics, bio-diesel fuel and technological solutions for maximal energy

efficiency engines with minimal adverse effects on environment [36].

Shane Curtis, Mark Owen, Terrence Hess and Scott Egan did the investigation

of effect of ethanol blends on SI engine. The objective of this research was to determine

the effect of ethanol blending on the performance and emissions of internal combustion

engines that are calibrated to run on 100% gasoline. Experimental tests were performed

on an engine using pure gasoline, 10% ethanol and 20% ethanol blends. The results of the

study show that 10% ethanol blends can be used in internal combustion engines without

any negative drawbacks. The fuel conversion efficiency remains the same, while CO

emissions are greatly reduced. 20% ethanol blends decrease the fuel conversion efficiency

and brake power of an engine, but still reduces CO emissions [37].

R. Scott Frazier investrigated the effects of ethanol gasoline blend in small

engines. In many parts of the United States, the use of ethanol/gasoline fuel blends is very

common. The state of Oklahoma only recently began using 10 percent blended fuels

(E10) in many service stations. Along with this new fuel availability are customer

concerns regarding compatibility with small engines such as lawn mowers and trimmers.

The following presents information so consumers can decide if using ethanol blended

fuels is appropriate for them. Also included are some basic suggestions to mitigate some

possible problems that might exist [38].

12