Download engine performance using gasoline ethanol mixture - e

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ENGINE PERFORMANCE USING GASOLINE ETHANOL MIXTURE TOWARD
OPTIMUM HYBRIDNESS ON HYBRID POWER SYSTEM 2.8 HP
Sena Mahendra
FPTK IKIP Veteran Semarang
Email : [email protected]
ABSTRACT
The research was conducted to determine the changeover optimum hybridity level on
hybrid power system. The writer used two kinds of fuel as the comparison against
premium. Fuel number one is the mixture gasoline and ethanol (gasohol) 5% (E-5) and
the second fuel is the mixture gasoline and ethanol (gasohol) 10% (E-10). Both are at
various levels of torque. The results show that the mixture 10% gasohol (E-10) increase
the hybridity level. The optimum hybridity level at 3.5 Nm of torque shows an increase of
42%. The same torque decrease power consumption only 10.2% and it showed the
increased of fuel consumption in 9%.
Keywords : Hybrid, hybridness , fuel consumption, optimum, ethanol mixture
1. INTRODUCTION.
Ethanol is short for ethyl alcohol (C2H5OH), sometimes it is called grain alcohol,
pure alcohol, absolute alcohol, or alcohol. Ethanol is used in various industries, such as
material for mixed liquor (sake or gin), cosmetic raw materials, fuel mix alcohol gasoline
(gasohol) on the internal combustion engine, and octane enhancer.
The research of the mixture ethanol and gasoline as a fuel for vehicle, have been
carried out in various countries. It will greatly reduce exhaust emissions and global
warming. In The Washington Auto Show, Ford Motor Company launched the Ford Escape
Hybrid E-85, it is a research vehicle, combining two petroleum-saving technologies hybrid-fueled electric power and flexible capabilities.
Hybrid powered system use two or more energy source at the same power
system. The combination will take a consideration upon advantage and disadvantage from
each system. Internal Combustion Engine (ICE) has an advantage on spontaneous
acceleration. Acceleration is needed to accelerate vehicle on a heavy situation because of
road load. On the other hand, ICE is not efficient when compared with electric motor.
ICE’s thermal efficiency is only about 28% and this condition because of heat loss on
cooling system, heat absorbption on silinder block, and high temperature emission.
If compared with ICE, electric motor works efficiently with no emission, but electric
motor need a huge electrical power to start. Based on the facts, there are some effort to
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combine both advantages from ICE and electric motor to make an efficient system with
low fuel consumption and low emission either. Specific fuel consumption and the power
used on each system are influenced by the load, while the load is cannot kept constant.
Due to the reason, the system must be managed but still concern on minimum specific
fuel consumption on ICE and electric consumption on electric motor.
This research was conducted to determine the changeover optimum level of
hybridity of hybrid power system. The fuel used is a mixture gasoline with ethanol
(gasohol) 5% and 10% at various levels of torque.
2. BASIC THEORY
Hight Heating Value (HHV) calculated using a bomb calorimeter experiment,
where fuel combustion is cooled to ambient temperature so most of the water vapor
formed by the combustion of hydrogen condenses and releases its latent heat. The data
obtained from the testing of the bomb calorimeter is the temperature of the cooling water
before and after ignition. Furthermore, to calculate the calorific value, can be calculated by
equation as follows:
HHV = (T2-T1-Tkp) x Cv (kJ/kg)
(1)
(2.1)
where:
HHV = High heating Value (kJ/kg)
T1
= Cooling water temperature before ignition (°C).
T2
= Cooling water temperature after ignition (°C).
Cv
= Specific heat bomb calorimetre (73529.6 kJ/kg °C).
Tkp
= Temperature rise due to ignition wire (0.05 °C).
Power is the amount of work done per time unit expressed in kilowatts. Objects
experiencing business processes will form the track with a certain distance per unit time
(t). Velocity of doing business that charged him to cover a certain distance per unit time is
called power or energy. Power can be calculated using the equation:
(2)
(2.2)
where :
P = Power (watt)
n = revolution per minute (rpm)
T = Torque (N.m)
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To determine the torque, following equation:
(3)
(2.3)
(4)
(2.4)
whereas :
with :
F = gravity (N)
m = mass of object (kg)
g = acceleration gravity (m/s2)
l = length of arm on dynamometer (m)
specific fuel consumption :
(5)
(2.5)
whereas:
(6)
(2.6)
where :
SFC = specific fuel consumption (kg/kW.h)
mf = fuel cinsumption (kg/h)
P
= power (kW)
b
= fuel used in test (cc)
t
= time required to discharge fuel in burette (s)
fibb = fuel density (kg/l)
3. RESEARCH METHOD
The first step, High Heating Value (HHV) test for gasoline and the mixture of
gasoline with ethanol (gasohol ) 5% and 10%. We use bomb calorimetre. The result show
that the comparison by the High Heating Value (HHV) for gasoline, gasohol E-5 and
gasohol E-10, valued at: 47206 kJ/kg, 46911.88 kJ/kg and 45882.47 kJ/kg.
The second step, experiment is done to find electric motor and ICE’s characteristic on
constant load and different revolution using brake dynamometer. The ascending of
revolution is 250 rpm on ICE and 50 rpm on electric motor.
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Data taken from ICE are revolution per minute, torque and time needed to finish 5
cc fuel of gasoline, gasohol E-5 and gasohol E-10. Then, the data taken from electric
motor are revolution per minute, torqe, voltage and electric current consumed by electric
motor at each revolution.
By the ICE’s testing will be calculated each Brake Specific Fuel Consumption
using premium, gasohol E-5 and gasohol E-10 to verificate the result of overall
experiment. Then, from electric motor testing it shows that there is an efficiency which is
the result of comparison between electricity consumption and brake power as a function.
This function will be used as approachment to find electric motor’s brake power on
hybrid system.
ICE’s specification :
Brand
: Multi Equipment.
Type
: 4 strokes OHV.
Bore
: 53 mm
Stroke
: 36 mm
Fuel
: gasoline
Fuel system
: carburator
Electric motor’s specification :
Revolution
: 1680 rpm
Max voltage
: 170 Volt DC
Max current
: 9,8 Ampere
Max power
: 1,5 kW
Dynamometer’s specification :
Brand
: De Lorenzo
Type
: Generator DC Shunt
Max voltage output : 220 Volt
Max current output : 22,7 Ampere
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Figure 1. Hybred powered system
Figure 2. Electric motor transmision’s ratios
The experimental method on hybrid powered sytem are following :
1. Testing are done on torque 1.5 N.m, 2.5 Nm, and 3.5 N.m.
2. Setting ICE’s revolution so the Torque Measuring Unit (TMU) displaying wanted torque.
Set electric motor’s on and set revolution until voltmeter shows positive nominal and
amperemeter on zero. It means DC electric motor does not works as a generator.
3. Decreassing ICE’s revolution by regulate throtle untill torque on TMU show decrease.
Then, increase electric motor’s revolution by turning voltage regulator untill torqe on
TMU show the torque wanted.
4. Repeating step 3 untill torque does not change when ICE’s power is affecting to torque
change.
5. Observing and processing the data based on time needed to burn 5 cc of fuel
(gasoline, gasohol E-5 and gasohol E-10), revolution per minute, torque, voltage and
ampere consumed by electric motor.
Power on hybrid power sytem is a combination of internal combustion engine (ICE)
power and electric motor power. To find the brake power on electric motor the writer uses
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the graph relation between electricity consumption versus electric motor’s shaft. The
graph gained from the earlier test on electric motor. Power on hybrid system can be
represented by equation :
PB = (f(PML)) + PMB
where :
PB
: hybrid system’s brake power
f(PML)
: graphical function from relation between electricity consumption versus
electric motor’s brake power
: ICE’s power
PMB
Hybridness is an index which is expressing percentage of electric motor usage on
hybrid system. When hybridness 1, it means system is using 100% power from electric
motor. Indeks of hybridness expressed by equation :
H=
where :
PML : electric motor’s power
PMB : ICE’s power
4. RESULT AND DISCUSSION
a. ICE (Internal Combustion Engine)
The test results show, the torque generated engine with gasoline is still highest
compared to the torque generated of engine fuel consumptions with gasohol E-5 and E10. The maximum torque generated engine with gasoline is 4.4 Nm at 3250 rpm and 3500
rpm. While the highest torque generated engine with fuel gasohol-E-5 is 4.2 Nm at 3500
rpm. Last, the highest engine torque with fuel consumption gasohol E-10 is 3.6 Nm at
3000 rpm.
Figure 3. Torque versus Engine Speed
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Figure 4. Power versus Engine Speed
Enigne’s max power which is used gasoline as a fuel is on 1.612 kW at 3500 rpm. Power
which is produced by the engine with E-5 is 1.539 kW. max power which is used E-10 has
1.157 kW max power at 3250 rpm.
Figure 5. Specific Fuel consumption versus Engine speed
Figure 5 shows, the highest specific fuel consumption of gasohol E-10 is 1.34 kg / kWh at
1750 rpm. At the same rotation, specific fuel consumption of gasoline and gasohol E-5 is
0.92 kg / kWh and 1:02 kg / kWh.
b. Electric Motor
Test on electric motor without transmision ratio shows a graph between electricity
consumption versus its brake power on 1000 rpm up to 1800 rpm. This result is shown on
figure 6.
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Figure 6. Brake Power versus Electric consumption.
Line function from this graph will be used for approach presumtive of electric motor’s
power based on its electric consumption.
Figure 7. Brake Power versus Electric Consumption.
Relation between electric motor’s brake power and torque versus revolution have linear
trend (figure 7).
c. Hybrid System
Figure 8. Power Consumption versus hibridness at torque1,5 N.m with gasohol E-5
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Figure 8 is, examples of comparison charts to find the optimum level of hybridity, electrical
consumption and fuel consumption at torque 1.5 Nm, 2.5 Nm and 3.5 Nm with gasoline
and gasoline-ethanol mixture.
Figure 9. Optimum Hybridness versus Torque
The results (figure 9) shows. At torque 3.5 Nm, the highest optimum hybridness use
gasohol E-10, which is 0.31. At the same torque, optimum hybridness gasohol E-5 and
gasoline occurred on the same level, ie 0.28.
Figure 10. Optimum Fuel Consumption versus Torque
The results (figure 10) shows, the highest fuel consumption is achieved by gasohol E-10
is 0.55 kg / h with torque 3.5 Nm. At the same torque, gasohol E-5 and gasoline is 0.51
kg/hour and 0.50 kg / hour.
Figure 11. Electric Consumption versus Torque
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The results (figure 11) shows at torque 3.5 Nm, the highest of electric consumption is
achieved gasohol E-10, which is 0.54 kW. At the same torque, electric consumption of
gasohol E-10 and gasohol E-5 is same, which is 0.49 kW.
5. CONCLUSION.
1. Higher content of ethanol in gasoline-ethanol mixture can decrease the fuel heating
value, because the heating value of ethanol is lower than the gasoline.
2. Higher heating value of fuel increases the combustion energy. The opposite, lower
heating value of fuel, it leads to the decrease of combustion energy.
3. There is no significant effect at the optimum hybrid between premium and gasoline
ethanol mixture.
4. Effect of gasoline with gasoline-ethanol mixture of fuel consumption on hybrid power
systems is very small. At torque 2.5 Nm, fuel consumption gasoline and gasohol E-5
there is a decrease of 5%. At the same torque, fuel consumption of gasoline and
gasohol E-10 is declined 7.83%.
5. There is no significant effect on electric power consumption of electric motors on hybrid
power system between gasoline with gasoline-ethanol mixture.
REFERENCES
Chalilullah, Rangkuti., “Panduan Praktikum Bom Kalorimeter”, Laboratorium Motor
Bakar Teknik Mesin USU, Medan, 1996.
Fuhs, A.E., “Hybrid Vehicles and The Future of Personal Transportation”, CRC Press,
New York, 2009, p.233.
Garett,T.K., “The Motor Vehicle”, Butterworth-Heinemann, London, 2001, p.4.
McCormick., “Technical Barriers to the Use of Ethanol in Diesel Fuel, 2001.
Sugiarto, B., “Motor Pembakaran Dalam”, Departemen Teknik Mesin Fakultas Teknik
Universitas Indonesia, 2005.
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