vega technical specification

vega Vibration Electrical Generator for Acyclism

Technical Documentation

S Y S T E M S E N G I N E E R I N G & T E S T S R I G S

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Pôle d’activités Yvon MORANDAT - 1480 avenue d’Arménie - 13120 Gardanne - FRANCE

tel. : +33(0)4 42 24 52 00 [email protected] www.nerys.biz

The torsional vibrations generated by internal combustion engines ACYCLISM

The operation of alternative internal combustion

engines involves alternance between compression

and combustion steps.

This means an alternance between positive torque

steps (the engine produces a mechanical work,

provided by the combustion) and negative torque

steps (the engine consumes a mechanical work, used

for the compression).

The engine torque used to run the vehicle is the average value of these positive and negative torques.

This alternance of torque involves an acyclism. The consequence is a non-uniform rotational speed that is composed of two components:

An average and uniform speed component

A pulsed component

THE ISSUE OF ACYCLISM

Although filtered by the flywheel, the acyclism propagates to the kinematic chain (clutch, gearbox, transmission), as well as the engine accessories (alternator, AC compressor, vaccum pump, belts, etc.). This generates harmful vibro-acoustic phenomena both for the comfort of the user and for the equipment subject to it (accelerated aging, loss of performance or functional characteristics). Today, due to increased performances and efficiency, optimized equipment and the growing concern for reliability, manufacturers integrate increasingly consideration of the acyclism in the technical requests both for the design of equipment and for carrying out the tests. Including acyclisme in their tests enables manufacturers to:

Caracterize the equipment performances

Check the equipment reliability and qualify the lifetime with endurance tests

Uniform mean speed Pulsed speed Acyclic speed

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HOW THE ACYCLISM IS GENERATED?

To simulate the engine acyclism on a test bench, tree methods can be applied:

METHOD Strengths Weak points

The mechanical generation of acyclism: using a drive shaft keyed so that the angle of the cardan break generates a sinusoidal speed on harmonic 2 between the two ends of the shaft.

Low cost Only the harmonic 2 is generated

Limited speed Encombrement The phase is

constant but not tunable

The hydraulic generation of acyclism: an hydraulic rotating actuator is used to add an angular oscillation to a constant speed provided by an electrical engine.

High level dynamic torque

Multi-harmonic generation possible

Tunable phase

High cost Technical

complexity Limitation due to

the hydraulic passband

The electrical generation of acyclism: An electric engine is used. The generation of acyclism is obtained by analog setpoint signal applied to the inverter.

Technical simplicity

Low cost Easy to use Multi-harmonic

generation possible

Tunable phase

Level of acyclism limited by the ratio torque/inertia of the engine



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NERYS STANDARD SOLUTION: VEGA, the Acyclism generator designed by NERYS, is intended for generate, measure and manage the

acyclism on an electrical engine. This allows to simulate, by the use of an electrical engine, the torsional

vibration naturally produced by combustion engines.

This is an easy and cost-efficiency way to simulate the acyclic environment of a real engine, and so to

test, validate and characterize the behaviour of equipments used on engines, as alternators, pumps,

transmission devices, etc.

SYSTEM LAYOUT

Fig. 1 General layout



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Includes the following parts:

An electric cabinet, with :

The protection and switching devices

The inverter

The electric devices for the control and safety

A control cabinet, with :

A computer (PC)

A data acquisition system

A front panel with buttons and light indicators

A synchron brushless servomotor

An incremental encoder used for the acyclism process control

A dedicated software managing the acyclism generator



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DETAILLED SPECIFICATIONS

Unit Version A Version B

Electrical engine : Technology Synchrone brushless motor

Nominal power kW 41 60

Nominal torque Nm 132 226

Max speed * rpm 3500 4000

Rotor inertia Kg.m² 0.013 0.039

Cooling Forced air convection

Electric cabinet : Power supply 400V 3-ph. - 48kVA 400V 3 ph. - 75kVA

Dimensions (L x P x H) mm 800 x 400 x 1900 ** 800 x 400 x 1900 **

Control cabinet : Power supply 230V – 1kVA 230V – 1kVA

Dimensions (L x P x H) mm 600 x 600 x 900 600 x 600 x 900

Acquisition system Embedded Real-time controller (National Instruments)

Features

Acyclism servo-control Level and phase

Generated acyclism order Fractionnary, from 1 to 5

Incremental encoder Imp/tr 640

Multi-order generation Optional, each order servo-controlled on level and phase

Performances ***

Exemple 1

Total inertia (tested equipment + interfaces) Kg.m² 0.015 0.05

Generated order 2 2

Rotational speed rpm 1000 1000

Max possible acyclism level % 21.5 11.6

Exemple 2


Generated order 4 4



Exemple 3


Generated order 1.5 1.5





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* Higher speeds are possible but request special bearings, deflux mode in the inverter, and liquid-

cooling for the motor and the inverter. These configurations can be proposed as specific

applications.

** +410 mm high with the brake resistance

*** The performances of the VEGA acyclism generator depend mainly on the inertia value of the

tested equipment and interfaces. The values mentioned in the above table are, in case of direct

driving of the tested device.

SOFTWARE FEATURES:

VEGA product includes the VASCO Acyclism software, that is the VASCO Suite software

package plus the Acyclism plugin with specific features for the control of acyclisme.

More detailed information on the standard VASCO Suite software package is available on the

following link: http://www.nerys.biz/index.php/lien-vers-vasco-suite.html.

VASCO Acyclism software can be implemented in two different situations:

Vasco Acyclism is used as a supervisor

The VEGA package is a subset of a global test rig controlled by a specific

supervisor. So, Vasco Acyclism acts as a « black box », and communicates with

the supervisor via DLL functions.

The Human Machine Interface presented below is the “VASCO Acyclism supervisor” and

allows the control of the speed and acyclism.



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From this software interface, the user can operate the following features:

Control the mean speed value of the motor :

Set manually speed value, or predefined speed profile

Control the acyclism :

Set manually order and level values, or 3D-chart appliance for the level

control versus the mean speed (from editable file)

Order sweep feature

Graphical overview for the raw dynamic speed measured on the motor shaft

Overall and autonomous security control :

Motor stop on specific thresholds available on all parameters

Max level acyclism template versus speed, defined in editable file

Software and hardware watchdog to secure the communication between the

computer and the real time embedded module

Time chart display of the mean speed and level of acyclism

All the standard features of the VASCO Suite package are available, and

particularly :

Easy creation of new user interfaces, including graph charts, digital displays…

Data logging, on frequency up to the acquisition frequency, with assistant for

configuration

In the case of an application without supervision, all the control functions are operated from

an exchange table managed by a DLL module delivered with the package. The corresponding

parameters will have to be managed in the main supervisor software of the test rig.



vega technical specification

Automotive