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CHAPTER 3

Materials and Methods

This chapter deals with the materials used (including their selection,

development/procurement and manufacturing) and the methods used for

conversion of the conventional TATA Indica Diesel car in to Hybrid Electric

Vehicle as well as the testing methods with experimental plan. Following main

points were considered:

i. Conversion should be economical and affordable.

ii. Conversion should be easy, such that an unskilled worker/mechanic

should be able to carry out the conversion within 4 to 5 hours, after

receiving necessary one day training.

iii. There should be minimum requirement of special tools for initial

conversion as well as for any service maintenance work to be carried out

on the HEV in future.

iv. Return on investment should be measurable and attractive for the user.

v. Convenient to use for the end customer / user / driver.

vi. Reliability and ease of maintenance.

vii. Ease of implementation even for vehicle manufacturer on the similar

new models cars OR newly designed models introduced in future.

viii. Satisfactory performance.

Part numbering system has been developed and bill of materials is prepared for

the conversion of conventional car into hybrid electric car. Process chart is

prepared to explain the sequence of operations as well as provides knowledge

for possibility of concurrent manufacturing of components and sub-assembly

and assembly, for reducing the time required for Conversion of Conventional

existing Diesel car in to Hybrid Electric car. This can be useful for

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understanding the disassembly/assembly procedure for maintenance and service

requirements.

3.1. Materials: The material, parts, subassembly and assembly components were

segregated into categories in the form of parts newly required for the

conversion and those removed from the existing conventional car which

are required to be reused without any modification, to be modified before

reuse or not required at all. The conversion of existing Diesel car in to

Hybrid Electric Vehicle (HEV) was carried out by using categorisation

of the material utilization, for simplicity of understanding (as shown in

Table: 3.1). There is no separate mention of all the remaining parts of the

conventional car, which continue to be part of the HEV. They are neither

removed nor required to be modified. Such components are part and

parcel of conventional car as well as HEV. In fact the entire car except

those parts mentioned in the Bill of Materials (Annexure: 1), are

functionally required in Hybrid Electric car as well. Hence, there is no

need to dismantle / remove them from the vehicle for conversion.

Annexure: 2 is prepared for explanation of the convention for levels in

BOM and Annexure:3 shows the elucidation for part numbering system

logic.

The above concept proved to be cost effective and gave clarity of understanding

for the repeatability of the conversion process.

3.2 List of Components:

This section covers all the parts required / used for conversion of

conventional diesel car into Hybrid Electric Vehicle as well as the test

equipments and experimental set up.

3.2.1. Import component:

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Only certain parts, which are usable as it is and not available in India are

developed as per our requirement and imported from China. They are:

i. Stator Assembly with winding (fig. 3.1 and Plate. 4)

ii. Rotor Assembly with Permanent Magnets (as per Fig. 3.1 and

Plate. 4)

iii. Controller Assembly (Plate. 12)

iv. Accelerator Pedal control (Plate. 13)

Table: 3.1: Segregation of Components and assembly parts

A TATA make : Indica DLS model, existing Diesel car.

B Part removed but not used in the finally converted hybrid electric car.

C Parts dismantled but reused for conversion as it is, without any

modifications or rework.

D Parts dismantled but reused for conversion after due modifications or

rework, as required (part no. is mentioned for the new part).

E New part or assembly directly fitted on to the vehicle, for conversion of the

conventional car in to hybrid electric car.

F Electric wires, Connectors, Battery, Battery Terminals & Switches.

G Test equipments for Fuel Consumption measurement, combined RPM

meter, Speedo meters and Trip meter, Ampere meters, Volt meter and its

components.

3.2.2. Standard parts: Following parts are standard parts readily available, chosen according to

the functional and performance demand / load characteristics:

i. All nut bolts

ii. Bearing inner 6206 RS1 (Make: SKF) – (as per Fig. 3.1)

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iii. Bearing outer 805945 (Make: FAG) – (as per Fig. 3.1) iv. A set of 4 nos. of 12 Volt DC Batteries and connecting cables

(Plate. 11) v. Wiring harness and switches (Annexure: 8)

3.2.3. Other parts: The other parts are designed and manufactured as per the functional and

performance requirement, as per optimum dimensions required.

i. Axle shaft (as per Fig. 3.2 and Plate. 3)

ii. Inner plate (Plate. 1)

iii. Grooved spacer (as per Fig. 3.4)

iv. Outer plate (as per Fig. 3.3)

v. Brake discs, RH and LH (Plate. 2, 3,6,7 and 8)

vi. Brake calipers, RH and LH(Plate. 7)

vii. Brackets for mounting brake calipers

viii. Battery charger (Plate. 14)

ix. Axle washers and axle nuts (Plate. 19)

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Fig. 3.1

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Fig. 3.2

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Fig. 3.3

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Fig. 3.4

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Plate 1: Cover Inner

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Plate 2: Cover Inner with Brake Disc

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Plate 3: Brake Disc, Cover Inner & Retainer with motor shaft assembly on Suspension arm

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Plate 4: PM BLDC Hub Motors Assembly

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Plate 5: Existing car with brake drum assembly

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Plate 6: RH Hub motor with Brake Disc assembly on car

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Plate 7: Hub motor with Brake Caliper assembly on car

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Plate 8: LH Hub motor with Brake Disc assembly on car

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Plate 9: RH and LH Hub motors assembly mounted on car

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Plate 10: RH and LH Wheels mounted on Hub motor

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Plate 11: Set of 4 nos. of 12 Volt Batteries

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Plate 12: Controllers mounted on dickey panel

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Plate 13: Accelerator Pedal

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Plate 14: Battery Charger

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Plate 15: Combined RPM, Speedometer and Trip meter

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Plate 16: Ampere meter, Volt meter and RPM meter

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Plate 17: Fuel Consumption measuring set up

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Plate 18: Laboratory test set up

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Plate 19: Hybrid Electric Vehicle ready for testing

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3.2.4. Test equipments & experimental set up: The test equipments and experimental set up was fabricated / developed as per

the requirement of measurement of performance parameters /test data, for

laboratory testing (Plate no.18) and while the vehicle is in motion (Plate no. 15,

16 and 17). Such gadgets were not readily available (e.g. the measurement of

Amperes drawn by each motor operating on 48 Volt - DC, but the meter supply

voltage being 12 volt DC, similarly all the other meters operating on 12 Volt,

DC vehicular battery of), hence were specially made as per order or fabricated.

They are all installed for experimentation only. All or any of these equipments

may not be part of mandatory requirement on the HEV usage for routine

purpose.

3.2.4.1. Volt meter: Since the main parameter essential for measuring / recording the performance

data required for comparison are state of charge (Voltage across the set of 4 nos.

12 Volt batteries connected in series) of batteries from starting of the test till the

batteries are not able to provide sufficient current required to run the motors (to

develop torque required to propel the car) any further, a digital Voltmeter is

developed (Plate. 16). The digital Voltmeter should be able to indicate state

charge for 4 nos. of 12 Volt batteries connected in series, but the LED’s display

of the volt meter is operational on 12 Volt vehicular battery. Because, the pack

of 48 Volt batteries is expected to be charged fully for running of motors and it

may be depleted as per the usage. If the volt meter is also operating on the same

48 Volt battery, it may show misleading readings and eventually fail

prematurely under fluctuating current drawn. It is important for driver to

know/note that how much charge is consumed and how much charge is still

remaining, at every stage continuously.

3.2.4.2. Ampere meter: Two nos. of Ampere meter (Plate. 16) were developed for measuring the current

drawn by each of the motors, to record the level of discharge current drawn at

different RPM, load and under varying state of charge of batteries. In

production vehicles, total current drawn by both Hub motors can be measured

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by combined single Ampere meter. Not only these meters will indicate

performance, it can help in diagnosis of any malfunction, in case of failures or

under performance / deterioration in output v/s input. An independent Ampere

meter for each motor can help identifying that which motor has developed fault

(e.g. if one of the motor is drawing excessive current as compared to other or

stopped working).

3.2.4.3. RPM, Speedometer and Trip meter for Electric motors: Two digital display meters (Plate. 15) working on the principle of ‘Proximity’

sensor based measurement of Motor RPM, separately for both RH & LH motors

are developed. These meters are able to measure the RPM and vehicular speed

(in unit of measure as Km/hr) of motor always and display the information on

distance covered (in Km unit), whether the vehicle is running on IC engine or

electric motors. This measurement will verify the recording of analog meter for

conventional vehicle running on IC engine, when the vehicle is moving in

straight ahead condition. And it will indicate the vehicle speed when the vehicle

is ‘Switched ON’ to move on electric motors. There is one switch provided for

switching ‘ON’ the display of Trip meter. It means, the Trip meter switch

should be put ‘ON’ along with Hub Motors dc voltage supply switch has been

put ‘ON’. So that the distance covered by the vehicle on electric battery charge

from fully charged condition to low voltage condition can be measured.

Two separate proximity sensors and combined RPM, Speedometer & Trip

meters are developed and installed for knowledge of variations under different

running conditions of straight ahead driving, turning and braking as well as

variations in respective hub motor performance due to inherent current drawn

conditions of RH & LH Hub motors.

Also for the routine usage purpose only one such measurement may be

sufficient, if the user wants to have the knowledge of distance/mileage covered

in electric mode.

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3.2.4.4Fuel Consumption Measurement set up:

Fuel supply line from fuel tank to fuel feed pump and return fuel line from fuel

injection pump to fuel tank are disconnected (both flexible rubber pipes near the

engine) at the front end. It was necessary to connect the measuring flask (Plate.

17), so that bleeding of fuel system is achievable and airlock does not occur

while running. Also the return line connection is connected to the measuring

flask, for accurate measurement of consumption of fuel.

3.3. Part Numbering System:

Part numbering system as per (Annexure: 1, 2 and 3) is developed for assisting

in identifying the components for reordering, storage, pick and assembly.

However, all components are designed such a way that sub-assembly of any

components cannot be wrongly done. It means “POKA YOKE” system is

adopted (which is called mistake proofing). The Bill of Materials (BOM) for the

conversion kit indicates all the part nos. as per the given part numbering system.

3.4. Methodology for Conversion in to HEV:

Methodology adopted for “reduction in consumption of fuel in existing diesel

cars” by fitment of two DC hub motors directly on rear wheels (for front wheel

drive vehicles with semi trailing link suspension), for conversion of existing

diesel car in to hybrid electric car, is discussed through four heads:

i. Process to be followed for assembly of motor on the suspension arm.

ii. Installation of suspension arm (with motor assembly) on the vehicle.

iii. Installation of test equipments on the test vehicle – conventional car

converted in to HEV.

iv. Testing of vehicle fitted with hub motors by running in IC engine mode

and hybrid mode to determine the reduction in consumption of fuel in

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existing diesel car, after converting it in to HEV, with two hub motors

fitted directly in the rear wheels.

The complete process sheet is given in Annexure: 4.

3.4.1. Process for Assembly of Motor on the Suspension arm: The details of step by step methodology is given below

i. Step by step process for assembly of motor on the suspension arm begins

with concurrent production of parts being kept ready as part of preparation

for sub assembly of components and then final assembly of all the

components and sub assemblies to make the assembly of motor on the

suspension arm. The parts that are required to be manufactured are Axle

shaft, Inner grooved sleeve – spacer, Inner cover plate and Outer cover

plate (with outer bearing hub).

ii. Initially the suspension arm assembly from the vehicle is made ready by

removing the existing axle shaft. The newly designed and machined shaft

is press fitted in the suspension arm, at the same location from where the

old axle shaft was removed.

iii. As a second step the brake disc is inserted on the shaft and then the Inner

plate assembly of Inner Plate and Inner bearing 6206 – 2RS1 is press fitted

on the axle shaft.

iv. The third step is to insert the Sleeve of set of wires inside the inclined hole

in the axle shaft.

v. Next step is to insert the grooved sleeve, as a spacer on the axle shaft.

vi. Press the woodruff key in the key slot provided on the axle shaft.

vii. Assemble the stator winding assembly on the axle shaft (by aligning the

key slot with the key on the axle shaft). Pull the stator winding from the

center of shaft from inside for clearing of slack, if any.

viii. Assemble outer bearing sleeve by press fitting on the axle shaft (against

stator hub).

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ix. Then insert the assembly – rotor housing (sub assembly of rotor housing

and permanent magnets), very carefully.

x. Fix inner plate assembly to the Rotor housing using six Allen key screws.

xi. Fix brake disc plate to the inner plate assembly with six counter sinking

screws.

xii. Assemble the outer plate assembly (sub assembly of outer plate and outer

bearing 805945) by press fitting.

xiii. Fix outer plate assembly to the rotor housing using six Allen key screws.

xiv. Use the special washer and fix axle nut. Tighten the axle nut with adequate

torque. Tighten lock nut.

xv. Fix the bracket for caliper mounting with the lower end of suspension arm.

xvi. Last step is to mount caliper assembly on the bracket.

(Steps from 3.4.1.i to 3.4.1.xvi are to be performed in the serial sequence only,

as mentioned above).

3.4.2. Installation of Suspension arm (with Motor assembly) on the

Test vehicle: The assembly of suspension arm with motor RH and assembly of suspension

arm with motor LH are to be located in RH and LH side of the rear suspension

respectively.

i. For installation of the assembly of suspension arm with motor for converting

the conventional car in to hybrid electric car, we have to prepare the car by

removing certain parts which are not to be used in the hybrid car. Hence, the

complete process includes removal of existing parts, discard non usable

parts and refit usable along with new parts. In the beginning the steps for

removal of parts /assembly parts are mentioned, followed by installation of

suspension arm with motor and other parts. Subsequently, steps required to

be followed for fitment of the parts removed but, required to be used with

the Hybrid car are explained. Some of the steps as part of safety requirement

are also list at appropriate locations.

ii. Disconnect battery – ve terminal connection.

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iii. Put wheel chokes in front and rear of the both front wheels.

iv. Put the rear end of vehicle chassis on firm and steady props with both RH &

LH wheels clear from the ground.

v. Remove wheel rim assembly (with tyre) by loosening four wheel bolts. All

four wheel bolts and wheel rim assembly (with tyre) are to be retained for

reuse with hybrid conversion.

vi. Dismantle shock absorber assembly lower mounting bolt and nuts. Shock

absorber and lower mounting bolt – nut should be retained for reuse.

vii. Dismantle hydraulic brake pipes and hand brake cable connections.

Hydraulic pipe and banjo bolts to be reused (but hand brake cable will

remain unused for test vehicle only).

viii. Dismantle front suspension arm nut – bolts for mounting suspension arm

with the chassis. The entire suspension arm assembly will be totally

disassembled from vehicular chassis. This entire set of assembly of parts

including Suspension arm, axle shaft, brake drum assembly, and brake back

plate (with brake shoe & wheel cylinder) is to be discarded (Plate. 5). Only

the mounting /fixing nut – bolts / hardware parts will be reused.

ix. Assemble the suspension arm assembly with motor by using / fixing front

end mounting nut – bolts.

x. Assemble the shock absorber lower end mounting nut – bolt to the new

suspension arm assembly with motor.

xi. Connect hydraulic pipe connection with banjo bolt and new banjo washers

to the brake calipers.

xii. Fix wheel rim with tyre on the outer plate of motor, with the help of 4 wheel

bolts.

xiii. Carryout the bleeding of hydraulic brake system, as per the standard

process, specified by vehicle manufacturer. xiv. Mount the controller in proper position with positive fixing and make

connect in to motor connectors.

xv. Connect 48 Volt battery bank (4 nos. of 12 Volt each battery connected in

series) + ve and – ve terminal cables connections to controller, motor, and

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accelerator pedal controller as well as ON – OFF switch. Ensure that all the

connections are properly insulated and securely fastened, to avoid short

circuit problem.

3.4.3. Installation of Test equipments: (contacts as per the fig. no. 3.21)

i. Connect ‘SHUNT’ on the battery positive cable – in series connection.

ii. Connect + ve and – ve connections of Ampere meter – RH as designated on

the ‘SHUNT’.

iii. Repeat these two steps above for connecting Ampere meter – LH, also.

iv. Connect Voltmeter + ve and – ve connections to the + ve and – ve terminal

connection of 48 V battery bank.

v. Connect all the three (two Ampere meters Rh & LH and one Volt meter to +

ve and – ve terminals of 12 V vehicular battery (or auxiliary 12 Volt battery),

because the power source for (LED lights) all the meters is 12 V DC.

vi. Mount proximity sensor in appropriate position.

vii. Connect sensor and the combined display of RPM/Vehicle speed & Trip

meter.

viii. Connect power source for this meter also from 12 Volt DC vehicular battery.

ix. Finally the set up for measurement of Fuel consumption (Plate. 16):

Importantly the main objective of this research project is “reduction in

consumption of fuel in existing diesel car”. The set up is consisting of a Glass

bulb of 1 liter capacity having two necks, one used for supplying diesel

(connected to the fuel filter inlet, by disconnecting supply line from fuel tank

to fuel filter and block it, so that fuel from the tank does not leak) and another

neck connected to the return fuel line from fuel injection pump to inverted

measuring flask (with its lower most outlet location is above the top level of

bulb). A measuring cylinder is connected to the flask reservoir. When the tests

are being conducted the bulb must be completely full without any air pocket,

so that the measured quantity consumed for a definite distance covered in IC

engine power mode OR Electric Motor driving mode as per the test “fuel

consumption” can be measured and recorded for comparison and analysis.

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The return of over flow of diesel from fuel injection pump is dropped back in

the measuring flask. Any simple type of flow meter or electronic flow meters

for can be also used.