Design and Fabrication of Electric Go-Kart

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Design and Fabrication of Electric Go-Kart

Aashish Porwal

Department of Mechanical Engineering Shivajirao Kadam Institute of Technology & Management,

Indore, Madhya Pradesh, India

Karunesh Chouhan

Department of Mechanical Engineering Shivajirao Kadam Institute of Technology & Management,

Indore, Madhya Pradesh, India

Nirmal Chohuan

Department of Mechanical Engineering Shivajirao Kadam Institute of Technology & Management,

Indore, Madhya Pradesh, India

Jhanvi Chatur

Department of Electronics & Communication Shivajirao Kadam Institute of Technology & Management,

Indore, Madhya Pradesh, India

Abstract:- The report aims at discussing the design procedure of the Go-Kart vehicle. The report is an account of application of extensive engineering concepts, production engineering, project management and team work. The report is a submission proof that these ideas have been efficiently and viably converted into a high performance vehicle.

With the vision to eliminate the harmful gases in the air caused due to smouldering of fuel and to form a pollution-free environment, we have designed an electric go-kart.

This report is aimed at designing and developing a working model of an electric go-kart. The design and fabrication of the go-kart are made simple so that it could be operated even by non-professional drivers. The design is made keeping in mind the high strength of vehicle which can sustain more weight and provide the best facilities at a low cost.

Keywords Go-Kart, Electric vehicle, Lithium ion Battery, High performance vehicle.

  1. INTRODUCTION

    The design has been approached by considering all possible alternatives for a system by modelling them in CAD software like CREO Parametric 3.0 and analysed it on ANSYS 16.0 FEA software.

    The design is mainly focused on the following objectives: Safety, Serviceability, Strength, Ruggedness, cost, durable, lightweight, high performance, ergonomics, and aesthetics.

    Sub-Departments for Design:

    Chassis Department Steering Department

    Brakes and Tyres Department Transmissions Department

  2. DESIGN METHODOLOGY

    Fig.1. Design Methodology

    Parameters

    Specifications

    Overall Length

    1.90691m (75.1)

    Overall Width

    1.1938m (47")

    Overall Height

    1.088m (42.82)

    Wheelbase

    1.1684m (46)

    Track Width

    0.9652m (38)

    Ground Clearance

    0.06326m (2.5)

    Max Speed

    21.37 m/s

    Max Acceleration

    3.16 m/s2

    C.G Height

    0.1397m (5.5)

    Stopping Distance

    1.240 m (48.8)

    Overall Weight

    190 Kg

    Steering Ratio

    1:1

    Weight Distribution

    35:65

    Motor

    48 V, 4.5KW BLDC

    Battery

    48 V, 50Ah Li-ion

    Brake Disc

    0.190m

    Turning Radius

    3.0214m

    Ackermann Angle

    21.8°

    Parameters

    Specifications

    Overall Length

    1.90691m (75.1)

    Overall Width

    1.1938m (47")

    Overall Height

    1.088m (42.82)

    Wheelbase

    1.1684m (46)

    Track Width

    0.9652m (38)

    Ground Clearance

    0.06326m (2.5)

    Max Speed

    21.37 m/s

    Max Acceleration

    3.16 m/s2

    C.G Height

    0.1397m (5.5)

    Stopping Distance

    1.240 m (48.8)

    Overall Weight

    190 Kg

    Steering Ratio

    1:1

    Weight Distribution

    35:65

    Motor

    48 V, 4.5KW BLDC

    Battery

    48 V, 50Ah Li-ion

    Brake Disc

    0.190m

    Turning Radius

    3.0214m

    Ackermann Angle

    21.8°

    TABLE I: COMPLETE VEHICLE SPECIFICATION

  3. MATERIAL SELECTION

    The material with low cost high strength and good weld ability must be used for the roll cage. After the extensive paper study of different material, we concluded to decide between SAE 1018 and SAE 4130.

    Alter discussion and analysis considering the physical strength, weight, availability and cost of the material we decided to use AISI 4130 as a roll cage material.

    TABLE II. MATERIAL COMPARISON

    Properties

    AISI 1018

    AISI 4130

    % carbon

    0.14-0.20

    0.28-0.33

    Density (g/cc)

    7.87

    7.85

    Modulus of Elasticity (GPa)

    200

    205

    Yield Strength (MPa)

    365

    435

    Ultimate Strength (MPa)

    450

    670

    Bulk Modulus

    140

    140

    Poissons Ratio

    0.29

    0.29

    Elongation at Break

    15%

    25.50%

    1. ROLL CAGE

      Calculation of Impact force:

      The estimation of impact force was done by using "Impulse- Change in momentum theorem.

      Impulse = F. t

      Overall Weight (m) = 190 Kg (max.)

      t = Impact time

      F. t = P

      Velocity (v) = 70Km/hr = 19.44m/sec

      F = 9237 N

      Conclusion:-

      Deformation= 0.0035142m Stress generated= 490.23MPa

  4. CAD MODEL

    =

    Impulse Time = Weight*(velocity/load)

    t= 0.4 sec

    1. Worst collision case

    2. General Case (Real world scenario)

      Front Impact Tests:

      Impact load calculations regarding front impact test are as follows:

      M (mass of the vehicle = 190kg Driver included) Velocity (v) = 90Km/hr = 25m/sec

      Fig.2. Isometric View Roll cage

      =

      F = 11875 N

      Conclusion:-

      Deformation = 0.52997mm Stress generated = 334.65MPa

      Thus in frontal collision, if the load reaches to the front most member the chassis and driver would be safe with

      F.O.S = 1.148 (considering yield point as material strength)

      Rear Impact Test:

      In rear collision, the vehicle is assumed to be stationary, fixed and another vehicle with same mass and collides with the former vehicle. Force is applied on rear portion of vehicle and all DOFS of front were constrained.

      Fig.3. Front View

      Fig.4. Left View

      Fig.5. Right View

      Fig.6. Top View

  5. CAE ANALYSIS

      1. Front Impact

        Fig.7. Total Deformation

        Fig.8. Equivalent Stresses

      2. Rear Impact

    <>Fig. 9. Total Deformation

    Fig.10. Equivalent Stresses

    1. STEERING

      Steering system is one of the crucial mechanisms, which are responsible for a smooth maneuver controlling of the vehicle. Apart from the controlling of the vehicle, steering system is expected to display its Good Ergonomics as well as the ease of use. The primary objective of the any steering mechanism is to reduce the steering effort as possible and for that, decreasing the steering wheel travel which results in a quick responsiveness of the steering wheel. The steering geometry is Ackermann-type steering mechanisms which uses four-bar linkages.

      Description

      Values

      Wheelbase

      1.1684 m

      Track Width

      0.9652 m

      Inner Wheel Angle

      32.6°

      Outer Wheel Angle

      22.2°

      Turning Radius

      3.0214 m

      Description

      Values

      Wheelbase

      1.1684 m

      Track Width

      0.9652 m

      Inner Wheel Angle

      32.6°

      Outer Wheel Angle

      22.2°

      Turning Radius

      3.0214 m

      TABLE III.

      Motor Voltage

      48V

      Motor Maximum rpm

      4500

      Maximum Velocity

      21.4 m/s

      Maximum Acceleration

      3.16 m/s2

      Torque on Wheel

      104.2 Nm

      Transmission Efficiency

      90%

      Tyre radius

      0.14m

      Total tractive effort

      143.2 N

      Rolling Resistance

      93.2 N

      Air Drag

      50 N

      Force at Wheels

      601.09 N

      Ackermann Angle

      21.8°

      Length of Tie Rod

      0.341m

      Length of Stub Axle

      0.132 m

      Ackermann Error

      0.4

      Steering Ratio

      01:01

      Normal Force

      686 N

      Lateral Force

      8750 N

      Tractive Force

      411 N

      Moment of NF

      4.05Nm

      Moment of LF

      38.7Nm

      Moment of TF

      53.4Nm

      Torque on Kingpin

      107.3Nm

      Pivot Distance

      0.3579 m

      Camber Angle

      2°

      Caster Angle

      2°

      King Pin Inclination

      2°

      Scrub Radius

      0.1317 m

      Caster Trail

      0.00433 m

      Ackermann Angle

      21.8°

      Length of Tie Rod

      0.341m

      Length of Stub Axle

      0.132 m

      Ackermann Error

      0.4

      Steering Ratio

      01:01

      Normal Force

      686 N

      Lateral Force

      8750 N

      Tractive Force

      411 N

      Moment of NF

      4.05Nm

      Moment of LF

      38.7Nm

      Moment of TF

      53.4Nm

      Torque on Kingpin

      107.3Nm

      Pivot Distance

      0.3579 m

      Camber Angle

      2°

      Caster Angle

      2°

      King Pin Inclination

      2°

      Scrub Radius

      0.1317 m

      Caster Trail

      0.00433 m

      Fig.11. Stub arm Total Deformation

      Fig.12. Knuckle Total Deformation

    2. TRANSMISSION

      Electric Powertrain – EVs have a single-speed transmission which sends power from the motor to the wheels.

      The motor is powered by a battery or by multiple batteries which store the electricity required to run an EV. The higher the kW of the battery, the higher the range.

      We have used chain drive type Transmission Between motor and drive shaft. The main advantage being its lightweight, highly efficient, low maintenance characteristics.

      TABLE IV. TRANSMISSION SPECIFICATION

    3. BRAKING SYSTEM

      The hydraulic disc brakes are used in motor vehicles to slow down its rotational motion by the help of frictional force. It is caused by pushing the brake pads against the disk rotor. It converts kinetic energy into heat energy that dissipates through the rotor vents and slows down the vehicle. Disc brake offers much better stopping performance.

      Advantages of Disc brake system:-

      • Ability to provide more consistent frictional behaviour.

      • Better braking performance at high speed.

      • Ability to lose heat developed due to friction quickly. Selection of brakes:

        These are considerations and certain selections that are selected for the better and safe braking. For the vary purpose master cylinder bore diameter was taken under consideration and calculation was done. Two discs have been used at the shaft for multiplying braking force. Some selected parameters are:-

        TABLE VII. BRAKE SPECIFICATION

        Parts

        Specification

        Overall Weight

        190 kg

        Deceleration

        0.7g

        Weight ratio

        35:65

        Tire Diameter Rear

        11

        Tire Diameter front

        10

        Static Rear Weight

        123.5 Kg

        Static Front Weight

        66.5 Kg

        COF Between Tire & Road

        0.7

        COF Between Pad & Rotor

        0.45

        Wheel Base

        46

        Height of Gravity

        0.1397m

        Dynamic Front Weight

        811.365 N

        Dynamic Rear Weight

        1052.535 N

        Master cylinder (bore diameter)

        0.014m

        Caliper (piston diameter)

        0.028 m

        Number of caliper piston

        2

        Load Applied on Brake pedal

        20 Kg

        Pedal Ratio

        5:1

        Force on Push Road

        1000 N

        Clamping Force

        7193.1915 N

        Braking Torque

        1009722.56 Nm

        Braking Force

        722779 N

        Deceleration

        38.04m/s2

        Stopping Distance

        1.240 m

        Stopping Time

        0.255 sec

        Brake fluid

        DOT 3

        Description

        Values

        Transmission Type

        Chain drive

        Motor Sprocket teeth

        13

        Shaft Sprocket teeth

        40

        Gear Ratio

        3.08:1

        <>Motor Peak Torque

        38 Nm

        Motor Maximum Power

        4.5 KW

        Motor Type

        BLDC

        TABLE IX. BATTERY SPECIFICATION

        Supply voltage

        48v

        Battery capacity

        50 Ah

        Cell voltage

        3.6v

        Efficiency(n)

        90%

        Weight

        34kg

        Cooling system

        Natural cooling

        BMS

        Integrated

        Charging Time (15Amp)

        7200 Sec

        Fig.13. Layout of braking circuit

    4. ELECTRICAL SYSTEM

      Objective:

      The E-power train system has the following objectives are:

      • To have a combustion free vehicle.

      • To have agility in the performance.

      • To achieve flexibility on the road.

      1. BLDC Motor:

        Brushless DC motors work on the same principle as that of a conventional DC motor. Due to its low noise and lightweight, it is being used for a vehicle. It requires low maintenance as well.

        TABLE VIII. MOTOR SPECIFICATION

        Criteria

        Specification

        Max power

        4.5KW

        Peak torque

        38N-m

        Max. RPM

        4500

        Rated Current DC

        94 Amp

        Weight

        12 Kg

        Continues Torque

        10.8 N-m

        Efficiency (n)

        89%

        Supply voltage

        48V

        Operating Temperature

        500 C

        Protection

        IP55

      2. Battery (Li-ion):-

        Lithium-ion batteries have a high energy density and are rechargeable. They are commonly used in consumer electronics. The life cycle and efficiency of Li-ion batteries are more as compared to the other rechargeable batteries.

        Fig 14: Battery BMS System

      3. Controller:

    A motor controller is a device used for operating an electric motor and is coordinated in some predetermined manner. A controller can have a manual or automatic system in order to start and stop the motor, for changing the direction of rotation from forward to reverse, for selection and regulation of speed and for limiting the torque. It is also used to protect the motor from overloads and faults.

    Other components:

    Fuse, Kill Switch, Contactor, FNR, Relay.

    Battery

    48V, 50Ah

    BMS

    Contactor

    Battery

    48V, 50Ah

    BMS

    Contactor

    Convertor (48V to 12V)

    Controller

    Motor

    Convertor (48V to 12V)

    Controller

    Motor

    Accessories

    Driveline

    Accessories

    Driveline

    Fig 15: Circuit Diagram

    Fig. 16. Circuit Diagram

  6. VEHICLE VIEWS

Fig.17

Fig.18

REFERENCES

  1. International GO-KART Championship Season 8Rules & guideline

  2. Practical Finite Element analysis Nitin S. Gokhale

  3. Strength of Materials R.K Rajput

  4. https://www.machinedesign.com/news/article/21817009/how- to-design-a-double-fourbar-steering-system

  5. https://www.bmikarts.com/Go-Kart-Spindles

  6. Race Car Vehicle Dynamics by Milliken D., Karsprak E., Metz L.and Milliken W. (2003).

  7. Thomas D. Gillespie Fundamentals of Vehicle Dynamics

  8. "Breaking system of go-kart" by IARJSET vol.4, issue 5 may 2017

  9. "Design of breaking system of go-kart"IJETER Volume 5, Issue 11, November (2017)

  10. B.Babu, M.Prabhu, P.Dharmaraj, R.Sampath 2014 Stress Analysis of Steering Knuckle of AutomobileSteering System International Journal of Research in Engineering and Technology.

  11. Advance vehicle Technology by HeinsHeisler

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