international efficiency challenge technical design …

INTERNATIONAL EFFICIENCY CHALLENGE

ELECTRIC VEHICLE RACES

TECHNICAL DESIGN REPORT

Delivery Date: 1 - 4 August 2021

UNIVERSITY: ERCIYES UNIVERSITY

VEHICLE AND TEAM NAME: VOLTAH2 – ENERJISTH2

CONSULTANT: ASST. PROF. SALTUK BUĞRA SELÇUKLU

TEAM CAPTAIN: EMRE ÖZDOĞAN

CATEGORY: ELECTROMOBILE HYDROMOBILE

CONTENTS

UNIVERSITY: ERCIYES UNIVERSITY ............................................................................................. 1

VEHICLE AND TEAM NAME: VOLTAH2 – ENERJISTH2 ............................................................ 1

CONSULTANT: ASST. PROF. SALTUK BUĞRA SELÇUKLU ..................................................... 1

TEAM CAPTAIN: EMRE ÖZDOĞAN ................................................................................................ 1

1. VEHICLE SPECIFICATIONS TABLE .................................................................................... 3

2. DYNAMIC DRIVING TEST...................................................................................................... 4

3. DOMESTIC PARTS ................................................................................................................. 4

4. MOTOR ...................................................................................................................................... 5

5. MOTOR DRIVER ...................................................................................................................... 6

6. BATARYA MANAGEMENT SYSTEM (BMS) ....................................................................... 7

7. BUILT-IN CHARGING UNIT ................................................................................................. 14

8. ENERGY MANAGEMENT SYSTEM ................................................................................... 24

9. BATTERY PACKING .............................................................................................................. 35

10. VEHICLE CONTROL UNIT (VCU) ....................................................................................... 41

11. DOOR MECHANISM ............................................................................................................. 54

12. MECHANICAL DETAILS ....................................................................................................... 55

13. FUEL CELL .............................................................................................................................. 76

14. FUEL CELL CONTROL SYSTEM ........................................................................................ 78

15. VEHICLE ELECTRICAL AND HYDROGEN DIAGRAM ................................................... 80

15.1 Vehicle Electrical Diagram ......................................................................................................... 80

15.2 Vehicle Hydrogen Diagram ........................................................................................................ 82

16. Cost calculation ....................................................................................................................... 86

3

1. VEHICLE SPECIFICATIONS TABLE

Feature Unit Value

Length mm 2687,9

Width mm 1241,1

Height mm 1172

Chassis Material Al 6063-T6

Shell Material Carbon Fiber

Brake System Hydraulic Disc, Front, Rear,

Handbrake Disc

Motor Type Ready-Made Gear Motor

Motor Driver Own Designs, Ready Product Domestic Product

Motor Power Kw 5

Engine Efficiency % %89

Electric Machine

Weight Kg 10

Battery Type Li-İon

Battery Pack Rated

Voltage V 50,4

Battery Pack

Capacity Ah 60

Battery Pack

Maximum Voltage V 58,8

Battery Pack Energy Wh 3024

Fuel Cell Power KW 1,2

Number Of Hydrogen

Cylinders # 1

Hydrogen Cylinder

Pressure Bar 2-10

Supercapacitor Ye Or No No

4

2. DYNAMIC DRIVING TEST

Dynamic driving test video has been shared in the link below.

https://sendgb.com/NsmGqVeuvQS

3. DOMESTIC PARTS

1. Motor Mandatory for Electromobile

and Hydromobile

☐

2. Motor Driver Mandatory for Electromobile

and Hydromobile

☐

3. Battery Management System

(BMS)

Mandatory for Electromobile

and Hydromobile

☒

4. Built-In Charging Dock Mandatory for electromobile ☒

5. Energy Management System Mandatory for hydromobile ☒

6. Battery Packaging Optional ☒

7. Electronic Differential Application Optional ☐

8. Vehicle Control System (VCS) Optional ☒

9. Fuelcell Optional ☐

10. Fuel Cell Control System Optional ☐

11. Insulation Monitoring Device Optional ☐

12. Steering System Optional ☐

13. Door Mechanism Optional ☒

5

4. MOTOR

Ready-made commercial geared motor with model number LEM-170-127 manufactured

by Lynch Motors will be used. The motor has a nominal operating voltage of 48V, a speed

of 3264 rpm and a torque of 16.2 Nm. Since the engine speed is above the required speed

for the vehicle, 1/4 gear transmission is used.

Thus, the engine speed was calculated as 816 rpm and the torque value as approximately

64.8 Nm. Technical data of LEM-170 motor is shown in figure 1, and efficiency, speed,

torque, and output power versus input current in figure.2. (Also see product data sheet.

https://www.lynchmotors.co.uk/pdfs/lmc-lem-170.pdf)

Figure 1: LEM-170’s Technical Data

Figure 2: LEM170’s Typical Technical Data Curve

6

5. MOTOR DRIVER

AXE 7234 model motor driver produced by Alltrax Inc. has been preferred. This motor

driver has been preferred because it meets the requirements of the motor to be used. It is

preferred because it is compatible with the motor operating voltage of 48V and meets the

starting current of the motor about 300A. Motor Driver Data is shown in table1. (Also see

product data sheet. https://alltraxinc.com/wp-content/uploads/2017/03/Doc100-004-

B_OP-AXE-Mini-Man.pdf)

AXE 7234 Permanent Magnet Motor Controllers

Battery Voltage 24-72 V

Current Limit 300 A

2 Minute Rating 300 A



Voltage Drop @ 100 Amp <0.16 V

Table 1: Motor Driver Data

7

6. BATARYA MANAGEMENT SYSTEM (BMS)

a) Circuit design

The curcuit down below which is curcuit design of BMS. Our BMS’s type is

passive balancing. This method is discharging from resistors. We see the LEDs instead

of discharging resistors which is providing balancing.

Figure 3.

Circuit has 4 section. First one is measurement section. We use resistors for

dividing voltage in the entry of BMS. Voltage divider provides us our battery pack’s voltage

measure in TTL(5V). After that we see analog Muxes which is 4067. These Muxes help

16 cells’ measurement in 1 ADC pin. Then we use voltage follower for get better signal for

amplification. The divided voltage from cell is amplifying by op-amp. PIC16F877A’s AN0

pin is connecting to op-amp which is amplified voltage for more resolution for ADC input.

8

This is the first section. We deal the battery measurement from picture down below which

is Figure 4.

Figure 4.

Now we will show section 2. Section 2 contains temperature sensor and

microcontroller. We are using LM35 for measure the temperature which is very cheap and

easy to use and helps microcontroller for more speed. Microcontroller is PIC16F877A. It

runs in 20MHz clock frequency which is maximum clock frequency for this model.

Microcontroller helps measure voltage levels and decides which cell needs discharge or

in critical situation. It drives the opto-couplers after that opto-couplers trigger mosfets what

drives resistor for discharging. Microcontroller helps to see what happens in system with

LEDs. LED green one indicates system is working. Orange LED indicates cells are

balancing and the last LED shows us there is critical situation in circuit. Working of BMS

is shown in Figure 5.

9

Figure 5.

Section 3 is about communication of BMS to vehicle control system unit. We can

understand what’s going on BMS. Vehicle control system shows to us information about

vehicle situation like BMS by screen in front of driver. We can see communication pins in

down below Figure 7.

Figure 6.

We came to final section. Section 4 balances cells. In this section, microcontroller

measures voltage level of cells and decides which cell has more charge. After that,

controller gives signal to opto-couplers to higher voltage level from others. Opto-couplers

switch MOSFETs which switches discharging resistors until higher voltage levels are

getting same voltage level from others. In this design we show LEDs instead of resistors

(we are driving LEDs by MOSFETs, opto-couplers aren’t driving LEDs). You should think

these LEDs discharging resistors. Section 4’s design is indicating in Figure 7.

10

Figure 7.

b) Balancing method

Cell-balancing circuits may be generalized into two categories: passive and active.

In passive cell-balancing circuits, energy is drawn from a cell having a higher SoC and is

dissipated as heat though a resistive circuit. While charging, current may be also

selectively routed around a cell having a higher SoC, via the resistive circuit, to avoid

further charging of the cell. Passive cell-balancing circuits may also be referred to as

dissipative cell-balancing circuits and such terms are used interchangeably herein.

Dissipative cell-balancing circuits are hardware efficient, generally requiring only a resistor

and a transistor for each cell, but typically waste energy in the form of heat. Our balancing

method is passive balancing.

An active cell-balancing circuit transfers energy from a cell having a higher SoC to

a cell having a lower SoC. Typically, the transfer of energy between cells is performed

indirectly through an energy storage element such as a capacitor or an inductor. Active

cell-balancing circuits may also be referred to as non-dissipative cell-balancing circuits

and such terms are used interchangeably herein. Active cell-balancing circuits are energy

efficient but are generally more expensive due to the cost of inductors and/or capacitors

and the need for extra wiring to transfer energy between the cells.

11

c) Control algorithm

We choose flowcharts to understand our BMS how it works.

Figure 8.

12

d) Simulation studies

In figure 7 we can see how we discharge cells. There are switches for opto-couplers

to drive MOSFETs. If we close any switch what will drive to related cell’s resistor consume

energy for discharging. The switches will be MCU’s pins. We just try to show mechanics.

We use Multisim software for simulation.

Figure 9.

e) Printed circuit studies

There’s our BMS’s PCB design. We designed with Altium Designer.

Figure 10.

13

f) Production studies

We didn’t print our BMS design. Give an order to Manufacturer. We assembled

BMS with related devices.

Figure 11.

Figure 12.

14

7. BUILT-IN CHARGING UNIT

Circuit Topology

The circuit topology of our vehicle's battery charger has been selected as half bridge. First,

we convert the 220V AC voltage from the network to 310V DC voltage with bridge diode.

What is required for the battery is the charging unit, which outputs at 600W at 60V voltage.

To operate the PWM control integrate, we convert the AC voltage we receive through the

transformer to 15V AC voltage. Here we again convert 15V AC voltage to 21V DC voltage

using bridge diode. Then we convert the voltage to 12V voltage with the voltage regulator

7812. We're sending the 12V voltage out of here into the integrate. Then comes the

location where the PWM signal needed for the trigger of the circuit is produced by SG3525

and the signal produced by the IR2110 MOSFET drive is applied to the MOSFET gate.

The frequency of the generated PWM signal depends on the resistance and capacitor

values of the SG3525 connected to the T and CT ends, where the output voltage can be

changed by changing the frequency. We're working at a frequency of 50 khz. When

MOSFET works like a switch, a current is cut and discharged 50,000 times per second

through the transformer, creating a variable magnetic field on that transformer 50,000

times per second. In this variable magnetic field, the current is induced in secondary

windings so that the desired voltage is obtained according to the number of bandages.

Finally, the voltage directed by fast diode and capacitors passes through the LC filter to

show the output voltage. The selected topology is half bridge topology and there is also

feedback of the circuit. The Pin 10 of the SG3525 is used to provide overcurrent

protection. Lithium batteries will be fed the battery management system in accordance

with the charging methods. The circuit was simulated, PCB design was made and copper

plaque was printed.

The circuit consists of four parts in general;

Fig.13: 220V AC voltage is converted to 310V DC voltage with the help of bridge diode

15

Fig.14: The part where the PWM signal is produced, the signal mosfets produced with

the IR2110 integration continue.

Fig.15: When the mosfets work like keys, a current is generated through the transformer

that is cut and drained 50.000 times per second, which induces the current in the

secondary windings within the magnetic field.

16

Fig.16: The voltage obtained at the exit is re-directed, the bridge is filtered with the help

of voltage capacitors pointed with the help diode

Primer Winding Turn Calculation

Parameters to be used for winding number;

Np= Number of turns for primer winding

F=Operation frequency (50000 Hz)

Ae=Core area (çekirdek alanı) (3.68 mm^2)

Bmax=1800 Gaussian mean value was obtained.

Magnetic flux constant for ferrite core = 4

Nominal voltage= 220*1.41=310V

Half Bridge Topology for voltage calculation = 310/2=155V

Common equation;

N_p=(155*〖10〗^8)/(4*50000*1800*3,68)≅11

The number of turns in the primary part was set to 1 * 11.

17

Secondary Winding Turn Calculation

Parameters to be used for winding number;

Ns= Number of turns for primer winding

F=Operation frequency (50000 Hz)

Ae=Core area (çekirdek alanı) (3.68 mm^2)

Bmax=1800 Gaussian mean value was obtained.

Magnetic flux constant for ferrite core = 4

Vout=60V

Common equation;

60=4*1800*3.68*50000*〖10〗^(-8)*N_s

From here N_s≅ 5 is calculated. Because the circuit has a symmetrical feed and the

wires of the secondary windings are wrapped in 2 * 5 turns so that the cable can resist

current.

Fig.17 Altium circuit drawing

18

Fig.18 Altium pcb drawing

Fig.19 PWM controller simulation

19

Fig.20 Mosfet simulation

Fig.21 Simulation of running the transformer

20

Fig.22 Printed circuit board

Fig.23 Integrated square wave output

21

Fig.24 Production studies

Fig.25 Production studies 2

22

Fig.26 310V DC output

In addition, component work files are shared via the link below.

https://www.sendgb.com/upload/?utm_source=JGgQAXy612r

Before Design Current Design

Circuit Design : - Half-Bridge

Power Level : - 540W

Output Voltage Range : - 60-70 DC V

Output Current

Oscillation :

- 8A

Input Power Factor : - 220ACV

Power Cycle Efficiency : - 0.879

PWM Control Integration : - SG3525

Protection Circuits /

Elements :

- -

Printed Circuit Size : - 212mm x 204mm

23

Fig.27

24

8. ENERGY MANAGEMENT SYSTEM

Control Algorithm

The energy management system to be used in the vehicle will be converted into two

power sources and DC-DC, which will deliver the voltage levels for these sources. The

location of the power supplies and DC converters in the vehicle is in figure-28.

The nominal operation of the Fuel cell, which is one of the sources, is 26V. Rated motor

operation is 48V. Fuel Cell Voltage Level the Voltage booster DC converter at the power

level required for the motor to run will increase the Power Cell Voltage to 48V.

Battery pack, another power source, is nominal 50.4V. But reasonable usage is 58.8V,

with a minimum of 28V.

Figure 28.

Since the nominal voltage of the power supplies in the topology is different, a converter

was needed to equalize each other. Since the use of converters for both is not good in

terms of efficiency, we designed a Boost type converter to equalize the fuel cell voltage

in our system with the battery pack. Figure-29. Again, we preferred the Boost converter

in terms of losses and efficiency.

25

Figure 29: First topology diagram

Figure 30: Initial topology Mosfet(gate) simulation

26

In the R&D studies in the first topology section, competence was tried to be established

in the subjects of boost converter and PWM design, which are the main requirements in

the system.

However, since only a boost converter would not be enough and it would be required for

the communication between sources, which is the main purpose of the energy

management system, there were options to design a system that would both generate a

pwm signal and control voltage by a smarter system (microcontroller) or an integrated

system. We preferred to design a voltage-controlled system. we did.

Circuit Design

Figure 31: Circuit diagram

If we talk about the IC, the control section consists of 1IN+(1), 1IN-(2), 2IN+(16), 2IN-

(15), DTC(4), FEEDBACK(3) and Output Control(13).

As seen in the block diagram, it contains 2 internal operational amplifiers (error amp 1-

2). These operational amplifiers can be used as error amplifiers or as comparators if

desired. The key difference between an amplifier and a comparator is that the amplifier

has a gain. In general practice, one of these op-amps is used as a comparator to limit

the transistor current, while the other is used to regulate the output voltage by forming

an amplifier with the FEEDBACK pin. As seen in the diagram, the FEEDBACK pin is

connected to the outputs of the op-amps. Thanks to this connection, a gain op-amp

circuit is created using a feedback resistor and it is possible to control the voltage in

smaller ranges.

27

Figure 32: Example Comparator design and amplifier design

According to the variable battery voltage in our designed circuit, a design that keeps the

EMS output voltage equal to the battery has been realized. In variable battery voltage, it

can be kept at the same level thanks to the frequency value changing with the voltage

Figure 33.

FUEL CELL VİN BATTERY VİN EYSOUT

33 51 51

20 51 51

25 43 43

27 37 37

Table 2: Equality check with randomly entered data

28

Simulation

Figure 33: EMS output 1485W

Figure 34: Mosfet gate trigger

29

Figure 35: Test part set up for frequency variation by changing the battery voltage, which

is the reference voltage

Altium Designs

Figure 36: The oscillator circuit set up for the integrated

30

Figure 37.

Figure 38: Transistors and triggered Mosfet to power the TL494 trigger

31

Figure 39: Voltage dividers and power sections

Figure 40: Altium pcb design

32

Development And Test Results

The randomly entered data given in Table 1 and the actual results and test stages of the

equality control studies are given in Figure 41 and Figure 42.

Since the sources are in the testing phase, they are included in the test as power source

(battery) and battery (fuel cell).

Figure 41: Fuel Cell Voltage

33

Figure 42: The voltage taken from the power source used instead of the battery and the

measured EYS output voltage.

34

Figure 43: Cooler used against Mosfet and Diode heating.

Figure 44: Printed circuit stage.



35

Previous Desing Current Desing

Circuit Topology : - Entegre kontrollü boost

Power level : - Max:1400W

Input Voltage Range

:

- Fuel cell Minimum in:24

Fuel cell Max:40

Battery min:28

Battery max:58.8

Output Voltage Range :

- EYS min:28

EYS Max:58.8

Power Cycle Efficiency : - %70

PWM Control Integration : - TL494

Semiconductor Power

Switches :

- IXFH320N10T2

Protection Circuits /Elements : - 100 amp fuse

Printed Circuit Size : - 10CM-15CM

-

9. BATTERY PACKING

Batarya paketini oluştururken kullanacağımız motorun akım, gerilim değerlerine ve yeni

yarışacağımız pistle ilgili yaptığımız hesaplamalara bağlı olarak sonuca vardık.

Seçtiğimiz hücrenin nominal voltajına, devamlı deşarj akımına ve yaptığımız ısıl

analizlere bağlı olarak 14 seri 10 paralel bir batarya paketi oluşturduk arabada 2 adet

paralel bağlı batarya paketi kullanacağız.

Kullanacağımız batarya hücresine ait datasheet:

https://www.batteryspace.com/prod-specs/9989.specs.pdf

https://www.batteryspace.com/prod-specs/9989.specs.pdf

36

a) Cell Properties:

Battery Material Li-On

Manufacturer LG

Nominal Voltage 3.6v

Minimum-Maximum Voltage 4,2v/2v

Rated Capacity (25 Degrees) 3000 mAh

Cell Weight 47 g

Continuous Discharge Current 10A

Maximum Discharge Current 20A

Cell Dimensions Ø18 X 65

Operating Temperature -20 ~ 60℃

Table 3: Cell Data

b) Specification Of Package:

Cell Capacity 1512 Wh

Number Of Cells 140 Adet

Total Weight 6580 Gr

Max Voltage 58,8v

Nominal Voltage 50,4v

Minimum Voltage 28v

Continuous Discharge Current 100A

Maximum Discharge Current 200A

Table 4: Package Data

37

c) Specifications Of Package Material:

Material Name PVC

Shrinkage Temperature 80℃

Melting Temperature 105℃

Rated Voltage 300v

Table 5: Package Material Data

d) Thermal Analysis Of Battery Modules Or Package:

Figure 45: Thermal Analysis Results With COMSOL Multiphysics

38

e) Placement And İsolation Of Modules And Packages:

Figure 46: Battery Cell

Figure 46: Battery Module Solidworks Drawing

39

Figure 47: Battery Module Punting Operations

Figure 48: Packaging Operations

40

Figure 49: Battery Module Final State

f) Battery Cooling System Design:

Figure 50: Battery Cooling System Design

41

10. VEHICLE CONTROL UNIT (VCU)

VCU Function:

The vehicle control system includes elements such as microcontroller, voltage regulator,

sensors, display, and relays. For the vehicle control system to control the vehicle, these

elements are harmoniously integrated among themselves.

An VCU is manufactured to control the front and rear of the vehicle. Two Arduinos were

used for the front and rear sides of the vehicle control system. SPI communication was

used for the communication of these Arduinos. Buttons, relays, headlights, and horns are

located at the front and a screen is used to transmit sensor data to the driver at the front.

Sensors are used in the rear to obtain values such as speed, temperature and current.

Voltage regulator is used to ensure the voltage that the system needs to operate. UDEA

Rf module was used to send information that needed to be monitored, such as sensor

data, to the computer at base station. Battery stabilization status, battery and cell

measurements will be carried out by BMS and communicated with VCU and displayed on

the screen. VCU is manufactured locally.

Main functions:

a) In-car communication system

SPI communication protocol is used for communication between Arduinos used for front

and rear side. SPI protocol was also used to communicate with other components of Car

such as Bms , Ems etc.

b) Monitoring the vehicle status and communicating it to the user

The information received and processed from the sensors is shown on the Nextion screen

and the information is displayed to the user.

c) Transfer of vehicle data to the monitoring center

Transfer of data from sensors to vehicle monitoring center by using telemetry.

42

Component Selection

Microcontroller:

Figure 51: ATMEGA328P Processor

The ATMEGA328P processor has been selected for the vehicle control unit.

ATMEGA328P is a processor designed with Atmel's RISC architecture. It has high

performance and low power consumption. It works range from -40 degrees to +85

degrees. It works with feed from 1.8 V to 5.5V. Supports communication protocols such

as SPI and I2C. Due to these features, the ATMEGA328P processor for VCU has been

used.

Display:

Figure 52: Nextion Display

43

Nextion display is used as a screen in the vehicle control unit. Communication with the

processor via serial port was provided. Due to its ease of use and compatibility with the

processor we use, it has been selected as a display for the vehicle control unit.

Temperature Sensor:

Figure 53:D S18B20 Temperature Sensor

The Ds18b20 temperature sensor is selected to measure the temperature in the vehicle

control system. The Ds18b20 temperature sensor is a digital sensor. The biggest factor

in selecting this sensor is that the sensor is sensitive, waterproof and has a digital sensor.

The discovery of the Arduino library provides ease of use. Used with 4.7k ohm resistance

connection for communication between Arduino and sensor.

Hall-Effect Sensor:

Figure 54: Hall-effect 3144E sensor

44

The hall-effect 3144E sensor was used to determine the vehicle's speed information. It is

the sensor that produces digital signals with a magnet located on the inside of the wheel.

In each round, the magnet activates the sensor, and a cycle is read on the processor. The

information read is replaced in the speed equation and the speed information is obtained.

Experimental Studies

1) Communication Protocol:

The SPI communication protocol for the vehicle is preferred for reasons such as being

faster, more efficient, and more functional than I2C like communication protocols. Rear

and front system communication simulation is shown in figure 55 and figure 56 shows

the communication experiment.

Figure 55: Schematic connections for SPI communication

Figure 56: SPI communication Proteus simulation The data package that was formed

was sent from master Arduino to slave Arduino

45

Figure 57: installation and operation of the simulated circuit

2) Sensor Experiments:

Sensor studies are primarily simulated on the proteus. Then, circuits were installed on the

breadboard and the experiment was carried out. Figure 58 is a single sensor

measurement and communication experiment, figure 59 and figure 60 sensor

experiments and outputs are seen.

46

Figure 58: Sending temperature data with SPI

(a)

(b)

Figure 59: Performing the temperature sensor experiment(a) and (b) output.

47

Figure 60 shows the experiment in which circuit temperature sensor and potentiometer

data were obtained. The potentiometer represents the data to be taken from the current

sensor.

(a)

(b)

Figure 60:. Conducting temperature sensor and potentiometer experiments(a) and (b)

output.

Temperature sensor and potentiometer data are obtained and shown on the LCD

screenas shown in figure 61.

48

Figure 61: Nextion display and circuit

3) Warnings and Signs

Warnings such as High Temperature and Low battery voltage are displayed in the lower

left corner of the screen. In case of High Temperature Warning (When the Safe

Temperature Limit Specified in the Rules is Exceeded), the Horn and Flasher got

activated. In addition, vehicle shutdown occurs when a Higher Critical Value is Exceeded.

Bms operating status is displayed in the lower right corner of the screen. BMS operating

status is indicated in 3 different colors. If the balancing situation is successfully terminated,

the green light will be displayed on the screen in case of continuing balancing, yellow light

and balancing, or an error in the BMS card. AKS tool screen shape. Shown in '62.

49

Figure: 62 AKS Vehicle display Image

Telemetry:

With the RF module in the rear system, temperature, current, voltage, speed information

was transmitted to the computer interface on the receiving side. UDEA UFM-A12 WPA

has been selected as rf module. The circuit required for UDEA operation is located built

into the AKS card. It consists of two parts: Receiver and Transmitter. Transmitter in Figure

63. In 64, the receiving System is shown.

Fİgure. 63 RF Module Transmitter Part Circuit

RF modules require two separate feeds, + 5V and + 3.3V. Two voltage regulators are

used to meet two different RF voltage GDI interface modules. + 5V output Max232, the

RF module feed, adjustable voltage regulator integrates to the LM317. LM317 voltage

regulator 3.3V resistance output voltage R1 and R2 resistors are set to apply to the 3.3V

voltage input to the RF module. The telemetry module in the vehicle is communicated with

the Arduino in serial and transmits the data to the receiver module.

50

(a)

(b)

Figure 64. RF Receiver (a)schematic and (b) PCB design

51

Figure 65. Pin Assignment to Atmega328

Figure 66 Control unit and communication ports

52

Figure 65 VCU main card 3D Model

Figure 66 Front Card (Dashboard) 3D model



53

Previous Design Current Design

VCU Functions : -

Speed Measurement,

Transfer of Vehicle Data

to the Monitoring Center,

Temperature

Measurement, Current

Measurement, In-Vehicle

Communication System,

Monitoring of Vehicle

Status and Transmitting

to the User

Controller Integrated

Circuit : - ATMEGA328P

Number of VCU I/O : - 23

Electronic Circuit

Design : -

Microprocessor and

semiconductors are used

Printed Circuit Board

Design : - SMD-TH mix

Printed Circuit Board

Production : - Handmade

Software Algorithm : - Atmel Atmege 328P

based.

Experimental Study : -

Experimental Study Has

Been Performed On

BreadBoard

Size (PCB/Box) : - 110x130 mm

54

11. DOOR MECHANISM

Figure.67Door lock mechanism design

55

12. MECHANICAL DETAILS

T

Figure.68 Vehicle mechanical dimensions

Aerodynamic of car:

(a)

Hydromobile

56

(b)

(c)

Figure.69 (a) Pressure contour side view, (b) Streamlines at 30 m/s, (c) drag coefficient

graph

The flow can be described by Navier-Stokes equation:

(1)

57

Rollbar & Rollcage design:

The rollbar & rollcage design was realized using SolidWorks. The model is realized by

means of tubular frame, having external dimension 30mm and wall thicknesses 3mm.

Figure 70: Rollbar & Rollcage design

Figure 71: Rollbar & Rollcage welding process

58

Strength analysis:

Strength analysis was performed using ANSYS Workbench. The roll bar height

dimensions are given in Figures.

Figure 72. Rear rollbar measures

Figure 73. Front rollbar measurements

When the point load is applied between the lowest point and the upper point of the roll

cage; 1kN was the calculated force in the horizontal direction . The analysis of the

59

amount of displacement as a result of the rollbar force to the front and rear H / 200 has

been shown. Both calculations are made for the front and rear rollcage (H: The

difference in height between the bottom point of the top spot).

Figure 74. Orientation and fixation points at which the force is applied

Figure 75. Mesh structure

60

Figure 76. 1000 N horizontal load status

Figure 77. Total 1000 N deformation amount when loading in Z direction

61

Figure 78. Z total deformation amount according to the force applied through

As shown in Fig. 42, a maximum deformation of 3.02 mm occurs under a load of 1 KN

when applied in the Z direction. In this case a horizontal loading of the rollbar and

rollcage design tools (Displacement a>b) it is seen that it is within the limits defined

as safe. Applied to the top spot in the rollcage, strength analysis showed 40kN applied

load under the point when tested in buckling of the rollbar sprain.

Figure 79. 40000 N. -Y direction load status

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Figure 80: the amount of deformation occurring in the direction -Y

Figure 81: corresponds to the load direction of the -Y - Von misses stress values

As shown in Figure, if a load of 40 kN is applied in the Y direction, a maximum of 0.6

mm deformation occurred on the roll cage. 3 mm deformation maximum total

deformation can be seen.

Outer Shell Production:

The shell was produced in the team laboratory together.

Stage 1: The outer shell of our vehicle is drawn in SolidWorks as shown in Figure x.

The shell production stage is as follows:

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Figure 82: Outer shell of vehicle

Stage 2: Using 3D CAD Data of our drawings, a block of expanded polystyrene is cut up

into into 3 parts (with a density of 30%) using a hot wire.

Figure 83. Cut with a hot wire EPS

Stage 3: Using CNC code we formed the shell structure from the EPS material.

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Figure 84. Starting material models (EPS)

Stage 4: Epoxy molding phase of EPS was used. The water-based putty was then

applied on the CNC machine 4 times.

Figure 85. Water based putty coating on model material.

Stage 5: After that fiberglass reinforcements were added and we obtained a hard shell.

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Figure 86. Obtaining hard shell material from EPS

Stage 6: Vehicle modeling is completed after abrasive lining on top of the glass fiber.

Figure 87. Car model

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Stage 7: The model was created by putting steel paste onto a smooth surface. Then the

female mold is made of polyester fiber glass fabric by applying a model bond

Figure 88. Fiber Glass Mold

Stage 8: The carbon fiber, peel ply fabric, vacuum net are placed on top of each other

in the fiber glass mold which is made smooth.

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Figure 89. Vacuum Infusion Preparation

Stage 9: Sealing is provided and covered with vacuum bag. Then vacuum pump and

epoxy connectors for infusion are placed on the mold.

Figure 90. Vacuum infusion

Stage 10: We applied the epoxy and the excess was withdrawn using vacuum pump.

Then the required heat treatment was applied and the body removed from the mold.

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Figure 91. Body produced by vacuum infusion method

Stage 11: Cavities needed for wheel parts, windows and wind shield were cut

and the necessary parts added by our team. The outer shell reached its final

state.

Figure 92. Final state of the body

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Chassis Analysis

When we make the required fixations in this pressure analysis made for the chassis and

put it on the load of 2500 N, our values are between 1 N / m ^ 2 and 2 N / m ^ 2 as seen

on the pressure graph. This indicates that our chassis is durable in the loading situation.

Figure 93: Chassis design

Figure 94. Chassis von mises stress

In this displacement analysis made for the chassis, necessary stabilizations are made and

when put on 2500 N load, as shown in the displacement chart, our value is max. 1.11 mm

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displacement. We decided that our chassis was appropriate because it was worth ignoring

the relocation.

Figure 95. Chassis total displacement

We can see that there is not much deformation in this case because it is between 0 and

2 as it is seen in deformation (distortion) chart when 2500 N load is placed on the load

region.

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Figure 96. Chasis volumetric strain

Support and axle tree analysis:

The pressure analysis for the left-hand motor housing shows that when we put on the 750

N load, the value is 0 N / m ^ 2 and 1.5 N / m ^ 2, as shown in the pressure graph, which

indicates that our motor housing is durable.

Figure 96. Left support von mises stress

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In the displacement analysis for the motor carrier on the left side, necessary fixings are

made and ... When placed on 750 N load, as shown on the displacement chart, our value

is max. 0.07 mm displacement. We decided that our motor housing is appropriate because

it is a value that can be neglected.

Figure 97. Left support total displacement

We can see that there is not a lot of deformation in this case because we have made the

necessary stabilizations in the deformation analysis of the motor housing on the left side

and the value is between 0.5 and 1.5 as seen in deformation (distortion) chart when 750

N is placed on the load.

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Figure 98. Left support volumetric strain

When we make the necessary fixings in the pressure analysis made for the wheel carrier

on the right side and put it on 750 N load, our value is 0 N / m 2 and 1 N / m ^ 2 as seen

on the pressure graph. This indicates that our wheel loader is durable in the load case.

Figure 99. Right support von mises stress

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In the displacement analysis for the right side tackle carrier, necessary fixings are made

and when the load is placed on 750 N load, as shown in the displacement chart, our value

is max. 0.02 mm displacement. We decided that our car housing was appropriate because

it was a value that could be neglected.

Figure 100. Right support total displacement

We see that there is not a lot of deformation in this case because we have made the

necessary stabilizations in the deformation analysis of the wheel carrier on the right side

... and when we put 750 N on the load, our value is between 0.5 and 1.5 as seen in

deformation (distortion) chart.

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Figure 101. Right support volumetric strain

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13. FUEL CELL

The fuel cell will be used as a commercial ready product. The product is the Nexa 1200

Fuel cell module, produced in partnership with Ballard and Heliocentris in the early

2000s. The Nexa 1200 Fuel cell module produces an irregular DC output of up to 1200

Watts at a nominal output voltage of 26VDC. By using an external fuel supply,

operation is continuous. Using hydrogen fuel, the Nexa™ module is extremely quiet

and allows indoor operations with zero emissions. Figure.102 shows Nexa 1200 Fuel

Cell module and Figure.103 shows Polarization and power curve. Figure.104 shows

Cell Input-OutpuIİnformation. (Also see product data sheet.

https://drive.google.com/file/d/12w3GEPU_aKDS9DclPKVHxWKYwLyNaGdA/view?u

sp=sharing)

Fig.102 Nexa 1200 Fuel Cell module

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Fig.103 Nexa 1200 Polarization and Power Curve

(a)

78

(b)

Fig.104 Fuel Cell (a) Output and (b) Input Information

14. FUEL CELL CONTROL SYSTEM

There is a built-in control system on the Nexa 1200 Fuel cell module. This control

system ensures safety and system stability. The Nexa 1200 Fuel cell module contains

all the auxiliary equipment necessary for the operation of the fuel cell as well as the

fuel cell. Auxiliary subsystems include hydrogen distribution, oxidizing air supply and

cooling air supply. Built-in sensors monitor system performance, and the control board

and microprocessor fully automate operation. The Nexa™ system also includes

operational safety systems for indoor operation. By making computer communication

with the fuel cell control card, instant data can be recorded, and performance can be

monitored through graphics. Figure.105 shows the system diagram of the Nexa 1200

fuel cell module and figure106 shows the fuel cell control system.

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Figure.105 Nexa 1200 System Diagram

Figure 106 Nexa 1200 Fuel Cell Control System

80

15. VEHICLE ELECTRICAL AND HYDROGEN DIAGRAM

15.1 Vehicle Electrical Diagram

(a)

81

(b)

Figure 107 Vehicle (a) Electrical Diagram (b) placement

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15.2 Vehicle Hydrogen Diagram

Vehicle hydrogen installation diagram is shown in fig.Figure 108.

Figure.108 Vehicle Hydrogen Diagram

The certificates submitted by the supplier company of the products such as Regulator,

Solenoid Valve, Check Valve, Relief Valve, Flame Trap to be used in the hydrogen

installation are shown in the figure.109 and figure.110.

S le i

alve

I :0-40 ar

ut:0-10 ar

Pressure

Regulat r

la e

Tra

1 ar

Relie

alve

C e

alve

y r ge

l eter

uel ell

I ter al

Relie

alve

uel ell

I ter al

S le i

alve

uel ell

I ter al

Pressure

Regulat r

uel ell

Ballar

Ne a

1200

uel ell

I let

Metal y ri e

Ca asity:1 00N

Pressure:2-10 ar

Sa ety

alve

83

Figure.109 Certificate for Products to be Used in Hydrogen Installation

84

Figure.110 Certificate for Products to be Used in Hydrogen Installation

85

The metal hydride tank, which is purchased from the Bulgarian tank company Labtech

Hydrogen that has 1500N Liter Hydrogen capacity and 25 SLPM output flow, which can

operate in the pressure range of 2-10 bar.

Şekil.111 HBond1500L Metal Hydride

86

16. Cost calculation

Product Name Quantity Price(TL)

Fuel Cell 1 Pcs 90.000 TL (Sponsorship)

MetalHydride HBond 1500L 1Pcs 17.583,29 TL

Motor 1 Pcs 28.000 TL (Sponsorship)

Vechile Control Unit 1 Pcs 3.980 TL (Sponsorship)

Energy Managementy System 1Pcs 4.760 TL (Sponsorship)

Built-in Charge Device 1Pcs 2.760 TL (Sponsorship)

Motor Driver 1Pcs 9.000 TL (Sponsorship)

Seat 2 Pcs 6.200 TL (Sponsorship)

Fiberglass 45m2 2.485 TL (Sponsorship)

Brake System 2 Pcs 6.425 TL (Sponsorship)

Steel Whell Rim 5 Pcs 3.980 TL (Sponsorship)

Battery Management System 1 Pcs 3.427 TL (Sponsorship)

Hydrogen İnstallation 7.426 TL (Sponsorship)

Mechanical Repair 6.250 TL (Sponsorship)

international efficiency challenge technical design …

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