Influence of Bioethanol–gasoline blended fuel on performance and emissions characteristics from...

Influence of Bioethanol–gasoline blended fuel on performance and emissions characteristics from port injection Sinjai Engine 650 cc

Bambang Sudarmanta1,a, Sudjud Darsopuspito1,b, Djoko Sungkono1,c 1Fuels and Combustion Engineering Laboratory, Mechanical Engineering Department ITS Indonesia

[email protected], [email protected], [email protected]

Keywords: SINJAI engine, bioethanol, gasoline, blended fuel, performance and emission.

Abstract. Performance and emissions characteristics from port injection SINJAI engine 650 cc

operating on bioethanol-gasoline blended fuels of 0%, 5%, 10%, 15% and 20% were investigated on

water brake dynamometers with power capacity 120 hp. The properties of bioethanol were measured

based on American Society for Testing Materials (ASTM) standards. Fuel consumption was

measured by the time fuel consumption per 25 cc of fuel in a measuring glass whereas combustion air

consumption was measured using an air flow meter. The emission parameters, exhaust gas

temperature and air fuel ratio were measured using STARGAS exhaust gas analyzer. The increase of

bioethanol content will increases the engine performance and reduces pollutan emission. The highest

engine performance produced by E15 blended fuel with increased torsi, mean effective pressure and

power output of 10,27 %, thermal efficiency 1,8% but specific fuel consumption increased

approximatelly 12,42%. This condition occurs at engine speed 3000 - 3500 rpm. While the emission

CO and HC emissions decreased significantly as a result of the leaning effect caused by the

bioethanol addition. In this study, it was found that using bioetanol-gasoline blended fuels , the CO

and HC emissions would be reduced appoximatelly by 55 and 32% Respectively.

Introduction

Developing renewable energy has become an important part of worldwide energy policy to reduce

greenhouse gas emissions caused by fossil fuels. Renewable alternative fuels, as defined by the

energy Policy Act of 1992 (EPACT), include alcohols (include biometanol,bioethanol and others),

natural gas, liquified petroleum gas, hydrogen, coal derived liquid fuels, biofuels (include biodiesel),

and electricity. These fuels are being used wordwide in a variety of vehicle applications. They are a

major force in the effort to reduce fossil fuels consumption and environmental impact (include

harmful pollutans and exhaust emissions) in the transportation sectors.

Bioethanol is one of fuels employed most widely, so many researcher was studying the effect of

bioethanol fuel on the performance and pollutant emissions of an engine by experiment[1-3] and

artificial neural network [4]. The reasons are in the followings [1]: First, it can be produced from

cellulosic biomass, such as trees and grasses and is called bioethanol. Secondly, bioethanol

(C2H5OH) is made up of a group of chemical compounds whose molecules contain a hydroxyl group,

OH, bonded to a carbon atom; so, the oxygen content of this fuel favors the further combustion of

gasoline. Besides, bioethanol is most commonly used to increase gasoline’s octane number. It can be

concluded that using bioethanol–gasoline blended fuels can reduced air pollution and the depletion of

petroleum fuels simultaneously.

According to these issues, the development of new clean-gasoline engines, such as injection

system fueled with bioethanol fuel, is important because it has at the same time the advantages of

higher thermal efficiency due to fuel injection and higher power output than conventional engines [5].

The injection system gasoline engine has also a better transient response, more precise control of the

air–fuel ratio, an improvement of fuel economy and a reduction of exhaust emissions. Moreover, the

higher compression ratio due to the reduced possibility of knocking, leads to an improvement of the

output performance by using gasoline bioetanol blended fuel [6].

Bioethanol has a heating value about 60% lower and higher research octane number than gasoline

fuel. These parameters allow higher compression ratio, higher boost in turbocharged engine and

require synchronization between the timing of injection and ignition. For the purpose of

Applied Mechanics and Materials Vol. 493 (2014) pp 273-280© (2014) Trans Tech Publications, Switzerlanddoi:10.4028/www.scientific.net/AMM.493.273

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synchronizing the time of injection and ignition then need a programmable ECU to adjust the degree

of suitability of the injection and ignition. Mapping the ignition timing to optimize performance and

emissions of port injection gasoline engine has been done by [7]. In the port injection system, fuel is

injected into the intake port of each cylinder, and there is an associated time lag between the injection

event and the induction of the fuel and air into the cylinder. During cranking and cold starting, a

transient film of liquid fuel forms in the intake valve area of the port. This causes a fuel delivery delay

and an associated inherent metering error due to partial vaporization, making it necessary to supply

amounts of fuel that significantly exceed that required for the ideal stoichiometric ratio. This puddling

and time lag may cause the engine to either misfire or experience a partial burn on the first 4–10

cycles, with an associated significant increase in the UBHC emissions [8].

The purpose of the present study is to investigate the influence of bioethanol-gasoline blended fuel

on performance and emissions characteristic from port injection Sinjai engine 650 cc. This engine is

equipped with a programmable electronic control unit which has the facility to adjust the suitability of

injection and ignition timings. ECU function is to control the quantity of fuel, injection timing,

ignition timing and engine speed by receiving signals from six sensors. These sensors are oxygen

sensor, manifold air pressure sensor, intake air temperature sensor, throttle position sensor, cooled

water temperature sensor and engine speed sensor. A multi port fuel injection system with is used to

inject the fuel into intake valve area of the port to the combustion chamber. The ignition system was

designed semi-static distributor with less ignition.

Experimental setup and procedures

In this study, the experiments were performed by SINJAI engine 20 kW, two cylinder, and ignition

spark plug. The engine specification is given in Table 1.

Table 1. SINJAI engine specification

Waterbrake dynamometer with power capacity 120 hp used in these experiments. The fuel

consumption was measured by the time fuel consumption per 25 cc of fuel in a measuring glass,

whereas combustion air consumption was measured using an air flow meter. The emission

parameters, exhaust gas temperature and air fuel ratio were measured using STARGAS exhaust gas

analyzer. The fuel measuring glass was fitted to gasoline engine and this contained

bioethanol-gasoline blended fuels alternately (E0, E5, E10, E15 and E20). A schematic diagram of

experimental setup is shown in Fig. 1.

Engine type SINJAI 20

Number of cylinder 2

Bore x stroke 76 x 71 mm

Displacement volume 650 cc

Compression ratio 9

Control system Programmable ECU

Fuel intake system multi port injection

Maximum torque 57 Nm /3000 rpm

Maximum Power 20 kW/4500 rpm

Coolant system liquid with Radiator

274 Advances in Applied Mechanics and Materials

Fig. 1. Schematic diagram of the experimental setup

The performance and emission from the engine running on bioetanol-gasoline blended fuels (E0,

E5, E10, E15 and E20) were evaluated. The properties of bioethanol-gasoline blended fuels are given

in Table 2.

Table 2. The properties of bioethanol-gasoline blended fuels

The bioethanol-gasoline blended fuels were prepared just before starting the experiment to ensure

that the fuel mixture was homogenous and to avoid the reaction of bioethanol with water. A series of

experiments were carried out using gasoline, and continued with the various bioethanol blends. All

blended fuels were tested with variable engine speed method. The engine was started using gasoline

fuel and it was operated until it reached the steady state condition. The engine speed, fuel

consumption, waterbrake load engine, emission parameters such as CO, HC, CO2, O2 and exhaust

temperature were measured, while the brake power, brake specific fuel consumption (bsfc), brake

mean effective pressure and brake thermal efficiency were computed. All experiments have been

carried out at full open throttle setting. To adjust ignition timing, programmable ECU system was

used.

Result and discussion

Engine performance is not the same for every engine speed so need to know the performance

characteristics of the engine for each engine speed. In addition, the effect of adding bioethanol will

also affect engine performance. Engine performance parameters include torque, power, mean

effective pressure, specific fuel consumption and thermal efficiency.

Torque is a measure of the ability to produce a working engine and is used to overcome the

obstacles in the way or to raise engine speed. Fig. 2. showed atendency that the torque starts to rise

from the lower engine speed to achieve maximum torque at a certain engine speed and further

decreased at higher engine speed. This is because that the higher the engine speed, the turbulence of

the flow entering the combustion chamber will be higher thus increasing the air mixing with the fuel

E0 E5 E10 E15 E20

Density kg/m3

ASTM D-1298 708,0 711,6 715,6 719,2 721,2

Viscosity cSt ASTM D-445 0,47 0,50 0,50 0,52 0,51

LHV kJ/kg ASTM D-240 44.929 43.154 41.414 39.490 37.730

Gasoline-bioethanol blend fuelsMethodProperty Unit

1. Fuel tank

2. Measuring glass

3. Filter fuel

4. Port injection system

5. Cables trottle

6. SINJAI engine

7. Exhaust muffler

8. Coupling

9. Tachometer

10. Water brake

dynamometer

11. Valve

12. water pump

13. Water reservoir

14. blower

Applied Mechanics and Materials Vol. 493 275

and flame propagation so that the output torque will increase. Along with the increase in engine speed

will be greater the friction losses, heat losses and uncomplete combustion process.

Fig. 2. shows the influence of different bioethanol–gasoline blended fuels on torque output. The

increase of bioethanol content will increases the torque output of the engine. The highest output

torque of 57.84 Nm occurs at engine speed 3000 rpm and produced by E15 blended fuel. Overall, the

addition of 15% bioethanol in gasoline fuel can increase the torque output of 10.27% compared to

using pure gasoline. This increase is due to that the addition of bioethanol properly to produce the

right chemical mixture so be perfect of atomization and combustion processes. It can be proved that

the HC emissions of E15 blended fuel was lower. While on E20 blended fuel, despite the atomization

process better but the calorific value is much smaller than the E15 blended fuel so torque is lower than

the E15 blended fuel. Added bioethanol produces lean mixtures that increase the relative air–fuel

ratio and makes combustion processes more efficient.

Fig. 2. Torque output at different fuel blends and engine speed

The amount of brake power is proportional to the torque output that occurs, because it is related to

the braking load by waterbrake dynamometer. The greater the braking load increased torque occurs.

Theoretically, when the engine speed increases, the power output will also increase. Fig. 3 shows the

influence of different bioethanol–gasoline blended fuels on power output. The increase of bioethanol

content will increases the power output of the engine. The highest power output of 19,59 watt occurs

at engine speed 3500 rpm and produced by E15 blended fuel. Overall, the addition of 15% bioethanol

in gasoline fuel can increase the power output of 10.27% compared to using pure gasoline. As same

with torque, this increase is due to that the addition of bioethanol properly to produce the right

chemical mixture so be perfect of atomization and combustion processes. It can be proved that the HC

emissions of E15 blended fuel was lower. Moreover that the heat of evaporation of bioethanol is

higher than that gasoline, this provides fuel air charge cooling and increases the density of the charge,

and thus higher power output is obtained. With the increase the addition of, the density of the mixture

and the engine volumetric efficiency increases and this causes the increase of power output.

Fig. 3. Brake power output at different fuel blends and engine speed

A parameter used to describe the performance of engines with reciprocating piston is the mean

effective pressure, mep or bmep. The mean effective pressure is the theoretical constant pressure that,

if it acted on the piston during the power stroke, would produce the same net work as actually

developed in one cycle. Fig. 4 shows the influence of different bioethanol–gasoline blended fuel on

mean effective pressure. The increase of bioethanol content will increases the mean effective pressure


of the engine. The highest bmep of 1128 kPa occurs at engine speed 3000 rpm and produced by E15

blended fuel. Overall, the addition of 15% bioethanol in gasoline fuel can increase the power output

of 10.27% compared to using pure gasoline.

Fig. 4. Bmep at different fuel blends and engine speed

The relationship between engine speed and specific fuel consumption for different fuel blends

(bioethanol and gasoline) is shown in Fig. 5. As shown in this figure, the bsfc decreases as the

bioethanol percentage increases. As engine speed increases reaching 3500 rpm, the bsfc decreases

reaching its minimum values. This is due to the increase in brake thermal efficiency. Fig. 5 shows the

influence of different bioethanol–gasoline blended fuels on brake specific fuel consumption. Fig.

shows that with the addition of the percentage of bio ethanol will result in higher sfc compared with

pure gasoline until 12,42%. This is due to the lower calorific value of bioethanol compared to

gasoline, so to produce the same power for a certain time would require fuel consumption is greater.

To use pure gasoline, minimum sfc is 0.21 kg / KW.jam at 3500 rpm engine speed.

Fig. 5. Brake specific fuel consumption at different fuel blends and engine speed

Thermal efficiency is a measure of the amount of utilization of the thermal energy stored in the

fuel is converted into power for the engine. Thermal efficiency value depends on the quality of the air

and fuel mixture is burned in the combustion chamber. Fig. 6 presents the effect of using bioethanol–

gasoline blended fuels on brake thermal efficiency. The highest brake thermal efficiency of 44,10

occurs at engine speed 3000 rpm and was produced by E15 blended fuel. Overall, the addition of

15% bioethanol in gasoline fuel can increase the brake thermal efficiency of 1.81% compared to

using pure gasoline. This is due to the lower calorific value of bioethanol compared to gasoline, so to

produce the same power for a certain time would require fuel consumption is greater. As the engine

speed increases reaching 3000 rpm, the brake thermal efficiency increases reaching its maximum

values.

Fig. 6. Brake thermal efficiency at different fuel blends and engine speed


Fig. 7. shows the concentrations of CO emission for different engine speeds. It can be seen from

this figure that when bioethanol percentage increases, the CO concentration decreases which means

the combustion is tuned to be completed. The CO concentration in the exhaust gas emission at 3000

rpm for gasoline fuel was 0,80 %vol, while the CO concentration were 0,64; 0,59; 0,52 and 0,38 %

vol at 3000 rpm each for the blended fuels of 5%. 10%, 15% dan 20%, respectively or if expressed as

a percent reduction in CO emissions compared gasoline fuel were 22%, 25%, 36% and 55%

respectively. This result indicates that bioethanol can significantly reduce CO emissions.

The reduction in CO concentration using 15% blended fuels until 36% is due to the fact that

ethanol (C2H5OH) has less carbon than gasoline (C8H18). Another significant reason of this reduction

is that the oxygen content in the blended fuels increases the oxygen-to-fuel ratio in the fuel-rich

regions.

Fig. 7. CO emission at different fuel blends and engine speed

Exhaust emissions of hydrocarbons (HC) is the amount of fuel is not burned during the

combustion process. In general, levels of HC emission decreases with increasing engine speed

increases due to higher rpm when the homogenity of a mixture of air and fuel, the better. But that only

happens to a certain rpm. When the rpm is accelerating again, the burning time will be more narrow

so levels of unburned fuel will be greater. HC emissions for different speeds are illustrated in Fig. 8.

The HC concentration in the exhaust gas emission at 3000 rpm for gasoline fuel was 183 ppm, while

the HC concentration of E5, E10, E15 and E20 at 3000 rpm were 152, 139, 137 and 125 ppm,

respectively. or if expressed as a percent reduction in HC emissions compared gasoline fuel were

16.94%, 24.04%, 25.14% and 31.69%, respectively in comparison to gasoline. This result indicates

that bioethanol can significantly reduce HC emissions.

Fig. 8. HC emission at different fuel blends and engine speed

Engine temperature is measured on the outer wall of the cylinder head. At this engine uses forced

air cooling medium and water, because there are as auxiliary blower for air flow to the outer cylinder

wall and radiator. Based Fig. 9 is seen that the magnitude of engine temperature will rise in line with

increasing engine speed. With increasing engine speed so the amount of fuel into the combustion

chamber more and more, so heat is released into the combustion cylinder walls are also more and

more, so engine temperature was rise.


Fig. 9. Engine temperature at different fuel blends and engine speed

Fig. 9 shows that the highest temperature occurred on E15 blended fuel, while the lowest

temperature when the engine is generated using the E5. temperature rise that occurs when the engine

using E15 blended fuel wass 7% compared to using pure gasoline. In general, the addition of 5%,

10%, and 20% ethanol resulted in 99.7% on gasoline, engine temperature tends to decrease, due to the

low calorific value of the blended fuel. Another thing different in composition E15, happening right

chemical mix that caused combustion to be more perfect. With the composition of the fuel

combustion process in combuation chamber happen quickly, so the energy contained in the fuel can

be separated by more perfect, than when using pure gasoline. Also can be also be caused by the

addition of bioethanol produces fogging better fuel, so fuel atomization getting better and better

combustion anyway. With good combustion the temperature generated in the combustion chamber

becomes higher. This can be proved by HC exhaust emissions followed by a low E15 E20. While on

E20 blended fuel, despite the fogging better but the calorific value is much smaller than the E15 so the

temperature chart down back.

Exhaust gas temperature measured at the exhaust hole using a thermocouple. In general, based on

the figure shows that the exhaust gas temperature increases with increasing engine speed. With

increasing engine speed so the amount of fuel into the combustion chamber for more, so the

combustion heat released also getting bigger, so exhaust temperature also increased. Exhaust

temperatures indicate the losses that occur in the combustion chamber.

Fig. 10. Exhaust temperature at different fuel blends and engine speed

Fig. 10 reveals that visible highest exhaust temperatures generated when the engine using the

bioethanol-gasoline blended fuels. Lowest exhaust temperatures generated when the engine using

E15 blended fuel. On average, a decrease of 15% compared to the pure gasoline. Also can be also be

caused by atomization of the fuel better, resulting in better combustion. This can be proved by HC

exhaust emissions followed by a low E15 and E20.

Summary

The influence of different bioethanol–gasoline blended fuels engine performance and pollutan

emission of SINJAI engine were investigated. The increase of bioethanol content will increases the

engine performance and reduces pollutan emission. The highest engine performance produced by

E15 blended fuel with increased torsi, mean effective pressure and power output of 10,27 %, thermal

efficiency 1,8% but specific fuel consumption increased approximatelly 12,42%. This condition

occurs at engine speed 3000-3500 rpm. While the emission CO and HC emissions decreased


significantly as a result of the leaning effect caused by the bioethanol addition. In this study, it was

found that using bioetanol-gasoline blended fuels, the CO and HC emissions would be reduced

appoximatelly by 55 and 32% Respectively.

Acknowledgements

This article is part of the research activities funded by the Research and Technology

Incentives SINas 2013 through the Institute's research and community service (LPPM )ITS for fiscal

year 2013, so in this opportunity, authors would like to thank Kemenristek SINas Incentive Program

and LPPM ITS thanks to funding that has been given. Authors also thank to the team SINJAI

engine (Yoga and Trihandoyo).

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