Harvesting Energy from the Vibration of Suspension of a Passenger Vehicle

MOHD AZMAN ABDULLAH, JAZLI FIRDAUS JAMIL

Department of Automotive, Faculty of Mechanical Engineering Universiti Teknikal Malaysia Melaka (UTeM)

Hang Tuah Jaya, 76100 Durian Tunggal, Melaka MALAYSIA

mohdazman@utem.edu.my http://www.utem.edu.my Abstract: - In this research, an energy harvesting device is developed and tested on a passenger car. The study started with observation of the potential vibrations from the suspension on a passenger vehicle running on a selected route. Based on the frequency and amplitude of the potential vibrations, a device is designed and developed. Among few designs produced, the best design is selected via design selection process. The device is then analyzed for further improvement. A prototype of the device is fabricated and design for manufacturing (DFM) is practiced. The device is tested on a test rig for laboratory scale experimentation procedure to observe its reliability and harvesting potential. The device is then installed on a passenger vehicle with minor modification on the suspension system. The vehicle is operated on the same route to monitor the electrical voltage harvested during ordinary driving on actual traffic. On a short distance travel, the device is capable of harvesting energy in term of electrical voltage to be stored in an onboard battery. With available components, the device can be used to harvest wasted energy during vibration of suspension system for frequent daily route and long distance highway travel. Key-Words: - Energy harvesting device, regenerative suspension, design selection, design for manufacturing. 1 Introduction

Suspension is a system that consists of a spring, damper and linkage that connect the sprung and un-sprung mass of a vehicle that allow the vehicle and the wheel to move independently from each other [1][2]. The damper is designed to dissipate vibration energy into heat to absorb the vibration produced from the irregular road surface. The green technology manufacturing is important in the future for the vehicle industry because suspension system has important source of energy dissipation and the energy is wasted. The wasted energy can be harvested and convert to regenerative energy to improve the vehicle fuel efficiency. Other than that, the harvested energy can be converted to electricity and stored for hybrid vehicle usage. The stored electricity can be used as the power for the vehicle electronics [3]. The regenerative shock absorber can reduces the fuel consumption as the harvested energy can charge the battery of the vehicle and help to power up the battery instead of using the alternator on the vehicle [4]. There are several ways to convert kinetic energy from vibrating structures to form a more usable energy. One method is using the hydraulic and

electro-chemical regenerative suspension. The research on the system has been done with a designed shock absorber [5]. The most efficient method is the electromagnetic regenerative suspension system. The harvested energy from the vibration is enough to complete the requirement in the consumption process for the system [6]. The recent research has discussed the use of electromagnetic suspension to absorb vibration in vehicle suspension system is an acceptable alternative to harvest the wasted energy from the vertical vibration on vehicle suspension system. The system is suitable for converting the kinetic energy to electricity to use on the electric vehicle and stored for vehicle electronics and high in performance. There are several more researches focused on the system. The system functions by the displacement of the body and wheel that cause relative displacement between the magnet and coil windings [7]. The reciprocating of the suspension will operate the regenerative suspension and the coil will cut the magnetic induction lines and produces current in the coil.

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2 Potential Vibrations from Suspension In order to harvest energy from vibration, the potential vibrations should be first studied and analyzed. The experimental vehicle is operated on a selected route and the vibrations from the driving are recorded and analyzed. In this study, the selected route is shown by Fig. 1. The length of the route is 9.6 km from Industrial Campus to the Main Campus of UTeM. This route is chosen since the students and lecturers are commuting 3 to 4 times on a daily basis. The specification of the vehicle chosen for the vibrations data collection is shown by Table 1. Before the experiment is performed. The vibration sensor and data acquisition (DAQ) box are positioned at the center of the gravity (COG) of the vehicle.

Figure 1: Selected route for vibration study.

Table 1. Vehicle specification. Criteria Specifications

Model Code 4G13 Transmission F5M21 Fuel system MPI Max. power 55kW(74hp)@6000rpm Max. torque 108Nm@3000rpm Bore & Stroke 71x82 Displacement 1299cc Max. speed 164 km/h Overall length 4360mm Overall width 1680mm Overall height 1385mm Wheelbase 2500mm Kerb weight 980 kg

The COG of the vehicle is derived using simple weighting technics at horizontal and slope of 5 degree increment on the front wheels. The sensor

and DAQ are shown in Fig. 2. The location of COG is usually at the handbrake of the vehicle (Fig. 3). Fig. 4 shows the result of vertical vibration data recorded. From this figure, it can be observed that there are vibrations with amplitude more than 2 m/s2 which are potentially can be harvested along the journey of the vehicle.

Figure 2: Vibration sensor and DAQ.

Figure 3: Sensor and DAQ at COG.

0 200 400 600-10

-5

0

5

10

Ver

tical

acc

eler

atio

n, m

/s2

Time, s

Figure 4: Vertical vibration from the vehicle. 3 Design Selection Based on the available stroke and space in the suspension system of the vehicle, 3 conceptual designs for the harvesting device are produced and compared for fabrication. Commercial computer aided design (CAD) software is used to draw the components and for assembly. Fig. 5 illustrates the

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first concept of the device. The design concept is square and simple. The joining is welded on the lower part of the housing. The inner part of the system can be changed by opening the upper cover. The material use for this concept is steel to prevent from rusting because the system is located under the vehicle body and exposed to the air surrounding. Fig. 6 illustrates the second concept of the device. The system is using a barrel like concept. The housing can be separated from the top cover and bottom cover. This concept eases the setting of the parameter in the system. The coil and magnet can be changed by disassembling the part of the system. This design use aluminium material which is light weight. Furthermore, the aluminium is anti-rusting material that is suitable to be use under the body of a vehicle. The light weight of the aluminium also gives advantage to minimize the weight after fully assembling the system. Fig. 7 illustrates the third concept of the device for the vehicle. This third concept uses the concept of double barrel which is doubling the system. This concept uses the same material of the second concept which is aluminium. As the system is double, the weight will be double but the size will be smaller for each barrel. The size of the system depends on the vehicle suspension space. The design is suitable for a certain vehicle model. Other than that, the cost of the fabrication will be high.

Figure 5: Conceptual design no. 1.

Figure 6: Conceptual design no. 2.

Figure 7: Conceptual design no. 3.

The number of windings that used on the coil can be calculated using the Eq. 1.

DcLN = (1)

Where N is the number of windings, L is the length of the wire used, (m) and Dc is the diameter of the coil, (m). The length of the wire used can be determined using the formula. The theoretical value of voltage produce by the device can be calculated using the Eq. 2.

BrVzDrNVe ⋅⋅⋅⋅= π (2)

Where Ve is the voltage produce in volt, (V), N is the number of windings, Dr is the average diameter of the windings, (m), Vz is the lateral velocity of the magnet, (m/s) and Br is the magnetic flux density, (T). The lateral magnet velocity, Vz can be calculated using the Eq. 3.

22 whhVVz+

⋅= (3)

The device is assumed to use the parameter shown in Table 2 and the theoretical value using Eq. 1, Eq. 2 and Eq.3 of each design is shown in Table 3. In Table 2, the material used for each design is stated with the estimation cost of fabrication for the system.

Table 2: Parameters assumption for the system. Speed, [km/h] 20 Magnetic flux density, [T] 0.2 Coil diameter, [mm] 0.29 Speed bump, [mm] h = 75, w =300

Table 3: Theoretical value, material and estimate cost for the system.

Criteria Design 1 2 3

No of winding 380 530 500 Length of wire, (m) 58 80 64 Voltage, (V) 0.93 1.30 1.22 Material St Al Al Estimate cost, (RM) 250 400 550

From the theoretical value, material and estimation cost, the design is analyse by using the weighted rating matrix as illustrates in Table 4 to get the best

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concept design. The criteria on the matrix are stated by referring each of the design concept and the theoretical value. The best concept design is then chosen to be fabricated. The design is chosen by taking the highest value in the total rating. The weight rating value is set from 0 to 4 which stand from unsatisfactory to a very good rating. From the table, design no. 2 is selected for fabrication.

Table 4: Weighted decision matrix.

Criteria Design 1 2 3

Low cost 0.30 0.20 0.10 Low maintenance 0.15 0.15 0.10 Easy to use 0.15 0.20 0.15 Light weight 0.10 0.20 0.15 Safe to use 0.30 0.40 0.40 High performance 0.45 0.60 0.60 High efficiency 0.45 0.60 0.60 Adjustability 0.10 0.15 0.15 Reliability 0.20 0.40 0.30 Durability 0.30 0.30 0.30 Robustness 0.30 0.30 0.30 Total score 2.80 3.50 3.15

4 Energy Harvesting Device Fabrication After the concept design is selected, the device is fabricated. Fig. 8 and 9 show the actual harvesting device fabricated and assembled.

Figure 8: Components of the device

Figure 9: Device assembly

5 Laboratory Testing Fig. 10 shows the installation of the device on the laboratory test rig. The tests are set at different parameters such as the number of winding and diameter of the coil. The test on the laboratory is performed on a test rig that moves in the vertical direction the same as in the suspension system on a vehicle. The frequency of the experiment is different which is set from 10 Hz to 50 Hz. The coil diameter used for the testing is 0.29 mm and standard magnet magnetic flux density of 0.2 T. The number of loop that is used in the system is different to record the different value of voltage produces by each set of coil loop. Table 5 shows the results of laboratory testing using different coil diameter. Here, it can be observed that, the smallest diameter of coil produces the highest voltage. Table 6 shows the results from the laboratory testing. From the result of experiment, the number of loop used in the system affected the voltage produces by the device. The greater the number of loop, the greater the voltage produces by the system. The highest voltage reading is occurs at 40 Hz frequency with the voltage value of 3.03 V.

Figure 10: Laboratory test rig.

Table 5: Voltage reading of different coil diameter. Coil diameter, mm Voltage, V

0.29 6.30 0.40 0.90 0.80 0.78

Harvesting device

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Table 6: Voltage readings from laboratory testing. No. of loop/ 400 250 100

Frequency (Hz) Voltage (V)

10 0.82 0.43 0.27 20 2.06 1.98 1.25 30 1.64 2.01 1.56 40 3.03 2.24 1.98 50 1.40 1.15 0.73

6 On-Vehicle Testing Fig. 11 shows the installation of the device on the rear suspension system of the passenger vehicle. Additional mounting plate is mounted on the vehicle suspension to hold the device. The parameters of the device is set for the testing on the vehicle is shown in Table 7. The vehicle is driven on the same route previously performed during potential vibrations data recording. The voltage readings of the device is recorded. Fig. 12 shows the testing result for 530 windings, Fig. 13 for 350 windings and Fig. 14 for 250 windings. The maximum reading of the device is logged when the car is passing through a road bumper. This is because the vertical movement of the car is high. Frequency is one of the other reasons that cause the voltage reading is high. A higher frequency will affect the reading of the device system. Other than that, the reading of the voltage is high when taking a corner with a high speed. A slalom type of driving will also give out high voltage reading compared to normal driving style. When the car is decelerating, the voltage recorded is also significant since the suspension system vertical movement is large. During a constant driving on a straight road, the voltage reading is slightly lower but in a constant value. This charge of voltage can be stored for alternative power for the car electronics and lighting. The use of this voltage charge can reduces the demands on the alternator and in the same time will reduce the fuel consumption of the car as the work load for the engine is also reduced. The maximum reading of voltage during experiment is |-5.6| V at 530 number of windings. Fig. 9 shows the recorded maximum voltage reading. The number of windings in the device plays an important role on the test. The higher the number of windings, the higher the voltage produces by the device system as shown in Table 7.

Figure 9. Maximum voltage reading of EReSS during experiment on car.

Figure 11: Harvesting device on suspension

Table 6: Parameters of the device.

Criteria Description Number of windings 530,350,250 Magnetic flux density, (T) 0.2 Magnet type Isotropic Ferrite Coil diameter, (mm) 0.29 Coil material Copper

0 200 400 600

-5

0

5

Vol

tage

, V

Time, s Figure 12. Device testing with 530 windings.

Harvesting device

Vehicle suspension

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0 200 400 600

-1

0

1

Vol

tage

, V

Time, s

Figure 13. Device testing with 350 windings.

0 200 400 600-1

-0.5

0

0.5

1

Vol

tage

, V

Time, s Figure 14. Device testing with 250 windings.

Table 7. Maximum voltage reading of different number of windings on car testing.

Number of windings Voltage, V 530 |-5.60| 350 |1.26| 250 |-1.17| 7 Conclusion In this research, the development of harvesting device for suspension system is presented. The device is designed based on the stroke and amplitude of potential vibrations from the vehicle on a selected route. Design selection for 3 concepts of harvesting device is performed and the device is fabricated. The DFM process is well established and demonstrated. The device is successfully tested in laboratory scale and on-the-road test. The device can harvest energy from the vibration of suspension. With available electric energy storage system, the device can be integrated and store the energy for the vehicle electronic system applications. 8 Acknowledgement The authors gratefully acknowledged the Advanced Vehicle Technology (AcTiVe) research group of Centre for Advanced Research on Energy (CARe), the financial support from Universiti Teknikal Malaysia Melaka and The Ministry of Education, Malaysia under Short Term Research Grant, Grant

no. PJP/2014/FKM(10A)/S01330 and Fundamental Research Grant Scheme (FRGS), grant no.: FRGS/2013/FKM/TK06/02/2/F00165. References: [1] Z. Jin-qiu, P. Zhi-zhao, Z. Lei and Z. Yu, A

Review on Energy-Regenerative Suspension System for Vehicles, Proceeding of The World Congress on Engineering 2013 Vol. III, WCE 2013, July 3-5, 2013, London, UK.

[2] M.A. Abdullah, M.A. Salim and M.Z. Mohammad Nasir, Dynamics Performances of Malaysian Passenger Vehicle, Proceeding of International Conference on Automotive, Innovation and Green Energy Vehicle (AiGEV 2014) Pahang, 26-27 August 2014, Malaysia, Organized by Universiti Malaysia Pahang, Paper ID: P027.

[3] R.H. Patil and S.S. Gawade, Design and Static Magnetic Analysis of Electromagnetic Regenerative Shock Absorber, International Journal of Advanced Engineering Technology Vol. III, April-June, 2012, 54-59.

[4] B.L.J. Gysen, P.J. Tom and J.J.H. Paulides, Efficiency of a Regenerative Direct-Drive Electromagnetic Active Suspension, IEEE Transaction on Vehicle Technology, 2011, Vol.60, No. 4.

[5] Z. Longxin and W. Xiaogang, Structure and Performance Analysis of Regenerative Electromagnetic Shock Absorber, Journal of Networks, 2010, Vol. 5, No. 12. doi:10.4304/jnw.5.12.14671474.

[6] A. Tonoli, N. Amati, J.G. Detoni, R. Galluzi and E. Gasparin, Modelling and Validation of Electromechanical Shock Absorber, International Journal of Vehicle Mechanics and Mobility, 2013. doi:10.1080/00423114.

[7] M.A. Abdullah, N. Tamaldin, M.A. Mohamad, R.S. Rosdi and M.N.I. Ramlan, Energy Harvesting and Regeneration from the Vibration of Suspension System, Applied Mechanics and Materials, 2015, Trans Tech Publications, Vols. 699, pp 800-805, doi:10.4028/www.scientific.net/AMM.699.800.

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