Experimental Study of Hybridness and Fuel Consumption Hybrid Powered System Bayu Aji Girawan Department of Mechanical Engineering Polytechnic of Cilacap

ABSTRACT This paper describes the experimental study of serie-parallel hybridness power system, based on 2.8 Hp internal combustion engine and 1.5 kW electric motor’s power. An apparatus has been made to analyze its caracteristics which is related to hybridness on optmimum fuel and electric consumption with varied torque. The result shows that on 1.5 N.m of torque, system will be optimum at 0.91 of hybridness. On 2.5 N.m of torque, system will be optimum at 0.55 of hybridness and on 0.27 N.m of torque system will be optimum at 0.50 of hybridness. This result can be applied as logical data input for fuel and electric consumption control system. Keywords: Hybrid, hybridness , fuel consumption

1. INTRODUCTION. The oil consumption of road vehicle is one the major issues in the world, especially in the field of energy and environment. Particularly, the oil consumption and carbon dioxide emission from road transportation in Indonesia have exhibited a dramatic growth. Internal Combustion Engine Vehicles (ICEVs) have been developed for over 120 years. Nevertheless, their energy efficiency has not been greatly improved from the original version. Actually, for modern gasoline fueled ICEVs have only about 25% of the fuel combustion energy is utilized for vehicle operation whereas about 40% is loss in the form of waste heat of exhaust gas [1]. ICE’s thermal efficiency is about 28% due to the heat losses on cooling system, heat absorbption on silinder block, and high temperature on exhaust gas emission [2]. Electric motor have a high efficiency because losses when it works is less than ICE with no emission. But electric motor need a huge electrical on its start. With that facts, so have been built a system to combine advantage of each system to make an efficient system with low fuel consumption and emission. Along with the technology research, nowadays many vehicles are built based on the hybrid technology. Hybrid powered system in automobile can be described as a vehicle that use two or more types of more prime mover as a propulsion, electric motor and gasoline engine. This combination of energy source was taken based on consideration upon advantage and disadvantage from each of its system. The hybrid vehicle can decrease the fuel consumption and increase the mileage. Fuel specific consumption and power on each system is influenced by loading which is can’t be kept constant. So power needed from each system must be managed but still concern on minimum specific fuel consumption on ICE and electric consumption on electric motor [3]. This research describes an objective of hybridness index between low specific fuel of ICE and electric traction motor consumption at the various given torque. The results are very useful as a logical information data for controlling the traction distribution system which represent movement mechanism of accelerator pedal.

2. RESEARCH METHOD Firstly, the experiment done to find electric motor and ICE’s characteristicusing brake dynamometer on constant load with variation on revolution. Revolution increases 250 rpm on ICE, and 50 rpm on electric motor. The data which gathered from ICE are revolution per minute, torque and time needed to deplate 5 cc of fuel. The data which gathered from electric motor are torque, voltage and electric current comsumed at each rpm.

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Figure 1. Hybrid Powered System

By the ICE’s testing will be calculated each Brake Specific Fuel Consumption (BSFC) to verificate the result of overall experiment. From electric motor testing, will be got comparison between electricity consumption and brake power as a function. This function is used as approachment to find electric motor’s brake power on serie-parallel hybridness power 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

Figure 2. Electric motor’s transmission

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The experimental method on serie-parallel hybridness power sytem are following this method: 1. The test is done on torque 1.5 N.m, 2.5 Nm, and 3.5 N.m. 2. Set ICE’s revolution so the Torque Measuring Unit (TMU) displaying wanted torque. Set electric motor’s on and set revolution untill voltmeter shown positive nominal and amperemeter on zero. It means DC electric motor does not work as a generator. 3. Decrease 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 torque wanted. 4. Repeat step 3 untill torque does not change when ICE’s power isaffecting on torque change. 5. Repeat this method for 2,5 N.m and 3,5 N.m of torque. Power on hybrid sytem is a married of electric motor’s power and ICE’s power, and represented by equation: PB = (f(PML)) + PMB where as : PB : hybrid system’s brake power f(PML) : graphical function from relation between electricity consumption vs electric motor’s brake power PMB : ICE’s power

Figure 3. Hibrid classification

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 PMB

: Electric motor’s power : ICE’s power

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3. RESULT AND DISCUSSION 3.1. ICE caracteristic

Figure 4. Torque and power vs revolution ICE test show relation between torque and power on figure 4. Max torque is on 4.4 N.m and 3750 rpm. Max power occured on the same rpm to. Relation between BSFC vs revolution is shown on figure 5.

Figure 5. BSFC vs revolution

3.2. 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 vs Electric consumption

Line function from this graph is used for approach presumtive of electric motor’s power based on its electric consumption.

Figure 7. Torque and Brake Power vs Revolution

Relation between electric motor’s brake power and torque versus revolution haslinear trend (figure 7). 3.3. Serie-parallel Hybridness Power System Result from serie-parallel hybridness sistem test ( figure 8) on 2310 rpm with torque 1.5 N.m, system generate 362,7 watt brake power. On this circumstance with BSFC and electric consumption as an objective, the optimum of hybridness is on 0,91. According ICE’s characteris, this engine has a bad BSFC on this rpm (figure 4). Using more electric motor’s power will be more appropriate.

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Figure 8. Hybrid system on torque of 1.5 N.m

On 2450 rpm with torque 2.5 N.m, system generate 641,08 watt. The result (figure 9) shows optimum hybridness on this circumstance is on 0,55.

Figure 9. Hybrid system on torque of 2.5 N.m According ICE’s characteristic, on this revolution ICE has a better BSFC compared with 2310 rpm (figure 4).

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Figure 10. Hybrid system on torque of 3.5 N.m

On 3240 rpm with torque 3.5 N.m, system generate 1186,92 watt. The result (figure 11) shows that sytem will be optimize on hybridness 0,27. It means power of ICE is 866 watt. According ICE’s characteristic (figure 5), on this revolution ICE has the best BSFC.

Figure 11. Engine Map on Best BSFC

4. CONCLUSION. Hybrid powered system will be optimize when meet a good configuration : 1. Right revolution with minimum BSFC. This is very important part to make a good configuration with minimum fuel usage. 2. A good efficiency from electric motor. When hybrid powered system having a good efficiency on electric motor so it has a good electric consumption. 3. Make an engine map is an absolute step to make an optimum system. This data which is used for logical data input of controll system.

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REFERENCES [1] Xiaodong Z., K.T., Chau and Chan C.C., Overview of Thermoelectric Generation for Hybrid Vehicles, Journal of Asian Electric Vehicles, Vol. 6, No. 2, p1119-1124, 2008 [2] Garett,T.K.,The Motor Vehicle, Butterworth-Heinemann, London, 2001, p.4. [3] Fuhs, A.E.,Hybrid Vehicles and The Future of Personal Transportation, CRC Press, New York, 2009, p.233. [4] Yap, W., K., and Karri, V., “Performance Simulation and Predictive Model For a Multi-Mode Parallel Hybrid Electric Scooter Drive”, International Journal Of Energy Research, pp. 67–83, 2009. [5] Choi, D. and Kim, H., “Evaluation of Fuel Economy for a Parallel Hybrid Electric Vehicle”, KSME International Journal, Vol. 16 No. 10, pp. 1287 –1295, 2002. [6] Husain, I., “Electricand Hybrid Vehicle Design Fundamental”, CRC Press, New York, 2005

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