Dynamometer System for Two ISSN 2395-1621 Wheeler … of Compact Chassis... · Dynamometer System for Two Wheeler Vehicle ... The chassis dynamometer is used to study the performance

www.ierjournal.org International Engineering Research Journal (IERJ) Special Issue 2 Page 4114-4118, 2015, ISSN 2395-1621

© 2015, IERJ All Rights Reserved Page 1

ISSN 2395-1621

Development of Compact Chassis

Dynamometer System for Two

Wheeler Vehicle

#1K.A. Tapre,

#2K.M.Narkar

[email protected] [email protected]

#12

Department of Mechanical Engineering, D. Y. Patil College of Engineering, Akurdi, Pune,

Maharashtra, India.

ABSTRACT

ARTICLE INFO

This paper deals with design and development of compact chassis dynamometer for two

wheeler vehicle. In comparison to prior chassis dynamometers, the current work aims to check

the performance of the vehicle by using air cooled eddy current retarder instead of wet eddy

current retarder to achieve the compact size dynamometer and reduce the volume and cost.

The chassis dynamometer consists of three major components roll set, the absorption unit and

a torque indication system.

In this paper the focus is on designing aspects of the chassis dynamometer system to avoid its

complexity. Design of Test rig equipment like Roller, Bed, Plummer blocks, Cardan shaft,

Mechanical coupling and Pneumatic arrangement for front wheel clamping is the objective of

this paper. The design validation of dynamometer and other parts is considered. The chassis

dynamometer is used to study the performance of vehicle under different load condition and to

perform different test on the vehicle.

Keywords- a Air cooled eddy current retarder, dynamometer system, roll set and two

wheeler.

Article History

Received :18th

November 2015

Received in revised form :

19th

November 2015

Accepted : 21st

November ,

2015

Published online :

22nd

November 2015

I. INTRODUCTION

In this paper different aspects of automotive chassis

dynamometer test system are explained in details. The

topics that will cover in this paper will include: what is

chassis dynamometer is, its importance, how it is operated

and a process of how to design, develop and validate a

chassis dynamometer.

A dynamometer is a general term for any device that can

apply a resistance load and measure that load and loaded

speed to determine the power output. Dynamometer can

measure wide range of power for different system but a

specific type of dynamometer must be selected or designed.

In this paper the chassis dynamometer is designed.

II.CHASSIS DYNAMOMETER

A chassis dynamometer is primarily used in the automotive

industry to measure the power that an automobile puts to the

ground or to the tires. Measuring the power at the tires gives

the designer a better understanding of actual vehicle

performance characteristics. Unlike the engine

dynamometer the chassis dynamometer includes the

transmission and differential losses to help designer’s better

understanding of the end power and torque capabilities of

the vehicle. Therefore it can be decide that the current

engine, transmission and differential configurations are

suitable to achieve the desired vehicle performance.

Chassis dynamometer is a service tool that allows to safely

placing controlled load on a vehicle through a load changing

device. It is a tool to evaluate a vehicles performance under

various load conditions.

In this paper the design part of the chassis dynamometer is

focused in order to reduce its complexity the small air

cooled eddy current retarder is used and according to the

retarder the design of test rig equipment like bed, roller,

cardan shaft, mechanical coupling is carried out.

III.MAJOR COMPONENTS

i. Roll set

ii. Absorption unit

iii. Torque indication system.

i. Roll set -

Roll sets come in variety of diameters

Selection depends on vehicle application

Automotive application- smaller diameter roll set

and large truck dyno- larger diameter roll set is

used.



All the members of roll set are dynamically

balanced

Rollers are of Stainless Steel tube with steel end

discs welded & fitted into a center shaft.

Complete roller assembly is stress relieved, prior to

precision machining.

Roller assembly is both statically & dynamically

balanced to make whole structure vibration free.

Roll sets are placed in a specially designed frame.

They are either to directly couple to the

dynamometer absorption unit or to a belt drive

system.

Roll sets may be of fixed dimensions to suit a

single vehicle.

It can be with adjustable version to accommodate a

variety of wheelbases.

With adjustable wheelbase, multiple vehicles can

be tested with a single machine.

Rollers are supported on the central shaft by heavy

Plummer block bearings.

Design of Roller-

The functions of roller are as follows- it receives the

power provided by the vehicle wheel and it absorbs and

stores this energy in form of angular velocity, acts of inertial

wheel. The characteristics that must have an optimal roller

are:

Inertia must be maximum.

Roller RPM at the end of the test must be

maximum.

Material Selected – Stainless Steel

Properties- Density 7900 kg/m

Configuration A

Configuration B

Out of the above two configurations A & B, for achieving

the

Compactness of the system configuration B has been

selected so that the retarder can mount below the test bed

platform instead of sideways. The space can be optimized

by using the configuration B.

Dynamometer rolls vary in size from 20cm to 127cm. The

smaller rollers have a greater potential for damaging the

tires.

During a dynamometer check, there is little weight on the

tires and only a small area of the tread face usually the

centre rib or centre portion of the tread is in contact with the

roll. Excessive heat builds up in this small area. If the test

runs too long, the excessive heat can damage the tire to the

point where it could fail later on the highway.

The roll diameter should be as large as possible to avoid the

damage of the tyre. The tyre diameter is in the range of 43

to 47 cm for the two wheelers. The diameter of roller can be

considered according to the analysis carried out for tyre.

Fig 1. 30 cm roller & 40 cm roller

So as the roller size increases the stress value in the tyre

decreases. Therefore the larger roller size i.e. 40 cm is

selected for the roller of the chassis dynamometer.

ii. Absorption unit

The power absorption units used in chassis

dynamometer are as follows-

- Hydraulic dynamometer

- Eddy current dynamometer

From the above mentioned power absorption unit Eddy

current dynamometer is used because of the following

reason-

In hydraulic dynamometer, water is used for torque

coupling, while it is magnetic coupling in E C

Dynamometer

Hydraulic dynamometers are unidirectional, while

E C dynamometers are bi-directional

Theoretically E C Dynamometer can be run

without water, but not hydraulic, as loading

depends on water in hydraulic dynamometer.

E C dynamometers are well adapted to computer

control, while hydraulic are not.

Response is quick in E C machines as compared to

Hydraulic machine.

E C absorption unit is selected considering the

compactness of the system.

These are electromagnetic load devices

It uses the magnetic field generated by an

energizing coils

The toothed rotor rotating in this field applies the

load on the vehicle



Load can be varied by changing current in the

energizing coil.

iii. Torque indication system –

In all cases, a torque arm is attached to the

absorption unit, at a fixed distance from its center.

The load cell at the end of the torque arm

experiences the force due to the reaction on the

casing of the unit

Torque can be measured by :

Torque = Force x Distance

Knowing the speed of the vehicle, H P can be

found by the relationship

H P = (torque * rpm) / Dyno constant

IV.DESIGN REQUIREMENTS

The two wheeler chassis dynamometer is primarily being

concentrated on the testing for different parameters and

accordingly tuning of the two wheeler vehicle. The

dynamometer must be capable of simulating road load and

of one of the following classifications:

A) Dynamometer with fixed load curve, i.e., a dynamometer

whose physical characteristics provide a fixed load curve

shape. Chassis Dynamometer with fixed load curve: the load

simulator shall be adjusted to absorb the power exerted on

the driving wheels at a steady speed of 40 km/h. This is not

a preferred type of dynamometer.

B) Dynamometer with adjustable load curve, i.e. a

dynamometer with at least two road load parameters that

can be adjusted to shape the load curve. Dynamometer with

adjustable load curve: the load simulator shall be adjusted in

order to absorb the power exerted on the driving wheels at

various steady speeds. This is a preferred type of

dynamometer.

C) It shall be equipped with means to simulate inertia and

load. These simulators shall be connected to the front roller,

in the case of a two roller dynamometer.

D) The roller shall be fitted with a revolution counter with

reset facility to measure the distance actually covered.

Performance Curve

The dynamometer specified here is designed to permit the

operation of checking the performance of two wheeler

vehicles in a compact space in a manner which simulates

actual road load operating conditions such as vehicle

frictional loss, vehicle and rider inertia, tyre rolling

resistance and aerodynamic resistance.

Torque measurement:-

Inertia of dynamometer rotor I kg/m2

Rate of increase in speed N rpm/s

Input torque to dynamometer T1 Nm

Torque measured by dynamometer T2 Nm\

T1-T2 = 2ΠNI / 60 Nm

V. AIR COOLED E C DYNAMOMETER

a Air-Cooled Eddy-Current Absorbers offer very quick

load control, moderate inertia, and high specific load

capacity, especially in the lower RPM working ranges of

most industrial-type engines. Its self-cooled rotors require

no external water supply. It is researched and developed

based on need of automobile test equipments like two

wheeler chassis dynamometer, emission testing equipment

and in instruments which uses a load and torque

measurement.

The parameters used for selecting the absorption unit are

as follows-

- Power requirement

- Torque requirement

- Compactness of the system

For two wheel vehicle specification the torque and power

requirement is considered. The specifications of 149 cc

vehicles are collected as maximum torque in the range of

12Nm at 5500 rpm.

For this specification the air cooled power absorber unit

having maximum torque of 27 Nm at maximum admissible

rpm is selected.



Fig 2: Isometric view of retarder in Creo 2.0

Fig 3: Expanded view of power absorber unit

Fig 4 Assembly Drawing of the Retarder

VI.TEST BED PLATFORM

a. Test Bed Platform designed considering all the types of

loads which are produced by vehicle and retarding forces of

dynamometer.

The major design requirements of test bed platform are:

a. - Vehicle weight and carriage

b. - Rotating forces generated by retarder

c. - Space reduction (compactness)

The design of platform is taken in to consideration of

compactness of the system. It is made suitable to

accommodate, roller, power absorption unit, pneumatic

cylinders for wheel clamping arrangement.

Selecting Materials-

The total weight exerted on the platform of the chassis

dynamometer is approximately around 2943N.

Accordingly materials selected based on their mechanical

properties are-

• Steel AISI 1020 Cold Rolled

• Aluminum 1050-H14

• Aluminum Steel ASTM A36

• Stainless steel AISI 1020 Cold Rolled

Fig 5 Two wheeler on Test Bed Platform

Fig 6- Arrangement of roller retarder below the bed

Fig.7 Conceptual drawing of test bed platform.

Front wheel clamping arrangement-

It consists of brackets moving in-out (Clamp-de clamp

position). Clamping brackets are mounted on the sliding

guides & are moved pneumatically. Brackets are provided

with sliding base to adjust the wheelbase, if required when

the test vehicle is changed. Rack and pinion arrangement is

provided to synchronize the clamps bracket motion. The air

supply is 5.5 bars to operate the pneumatic mechanism.



Drive Shafts-

Also known as propeller shaft or cardan shaft & used for

mechanical power transmission from engine to

dynamometer.

Data required for calculation to select a suitable shaft is –

-Speed range & torque characteristic of engine to be

tested

-Rotational inertia of engine

- Load factor with reference to nominal rating of shaft

-Maximum engine torque

-Whirling of shaft

-Degree of misalignment of engine & dynamometer

Wrong choice of cardan shaft may give rise to following

problems-

-Torsional oscillations

- Vibration of engine or dynamometer

- Whirling of shaft

- Imposition of axial load on bearings of engine or

dynamometer

Never make any alteration in the original shaft.

Never re-weld the cardan shaft.

VII.CHASSIS DYNAMOMETER OPERATION

Vehicle is driven onto the roll set of the chassis

dynamometer.

Vehicle is secured either using a strap/chains or

free wheel clamping device

As a safety, rotating wheels should be covered

with a wire net to prevent accident due to escaping

of a boulder stuck in the tire.

The vehicle then performs a series of tests. These

conditions are those the vehicle would face during

its intended use.

Automated tests are also possible depending on the

control system, supplied with the chassis

dynamometer.

Two wheeler engines are air cooled

Tests on two wheeler for –

Brake testing.

Speedometer testing.

Acceleration Time Measurement.

To measure the maximum velocity of the

vehicle

VIII.FUTURE WORK

Assembly of all fabricated parts.

Testing of the assembly.

Testing vehicle performance on chassis

dynamometer.

Results and conclusions.

IX.CONCLUSIONS

In this paper the designing aspects of the chassis

dynamometer system are considered to avoid its complexity.

The roller is which is driven by vehicle wheel is absorbing

the power. This power is drive by belt drive to the retarder.

The retarder is mounted below the test bed platform so the

system becomes compact. The use eddy current retarder

instead of hydraulic retarders is the reason for the

compactness of the dynamometer system.

ACKNOWLEDGMENT

I would like thank the many people who have contributed

to this research. I would like to thanks my advisor Prof.

K.M. Narkar for sharing his knowledge with me and for

providing me with much guidance, support and

encouragement.

REFERENCE

a

[1] Martyr, A and Plint, M.A., Engine Testing: Theory

and Practice, 3rd

ed., Elsevier Ltd. Burlington, 2007,

pp. 452-480.

[2] Mate, N.R and Dhande, D.Y., A study of the two

wheeler retarder type dynamometer system, Int.

Journal of Innovative Research in Science,

Engineering and Technology, 2014, 3(2), pp. 9057-

9061.

[3] Su, D.T., Shiao.,Y.S. and Yang., J.L.,Design and

implementation of a chassis dynamometer for testing

battery-powered motorcycle, WSEAS Trans.,2008,

7(10), pp. 879-889.

[4] Jirawattanasomkul, J., and Koetniyom, S., Design

and development of road load conditions for chassis

dynamometer, International Conference on Production,

Materials and Automobile Engineering , King

Mongkut University North Bangkok, Bangkok,

Thailand, 2012, pp. 153-157.

[5] Yunda, H.U., The research on test-bed test system

of automobile eddy current retarder, International

Conference on Future Electrical Power and Energy

Systems, zhejiang industry &trade vocational college,

Wenzhou,China,2012,pp.1351–1357.

[6] Patent no. 3,940,978,”United

States”,Mar.2,Motorcycle Dynamometer, 1976.

Documents

Dynamometer System for Two ISSN 2395-1621 Wheeler … of Compact Chassis... · Dynamometer System for Two Wheeler Vehicle ... The chassis dynamometer is used to study the performance