European Automotive Research Partners Association aisbl ... - EARPA

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European Automotive Research Partners Association aisbl ... - EARPA

European Automotive Research Partners Association aisbl

36-38 Rue Joseph II B-1000 Brussels, Belgium

Tel +31 888 668 287 Fax +31 15 269 21 11

EARPA POSITION PAPER

NOISE, VIBRATION AND HARSHNESS RESEARCH PRIORITIES OF ROAD TRANSPORT

17 October 2011

_______________________________________

1. THE EARPA “NOISE VIBRATION AND HARSHNESS” (NVH) TASK FORCE

Founded in 2002, EARPA is the association of European automotive research organisations. It brings

together the most prominent independent R&D providers in the automotive sector throughout Europe. At

present, EARPA counts 39 members ranging from large and small commercial organisations to national

institutes and universities.

The Task Force NVH was formed in 2005 in order to contribute actively to the European research in road

transport NVH for shaping the sound of tomorrow’s on-road mobility. Thus, the main goals of the Task

Force NVH are

• to emphasize the importance of NVH research in road transport, especially in view of CO 2

discussions, light weight design and electrification,

• to identify technology needs and research gaps yielding input to future R&D programmes,

• to develop and foster cooperation and innovative projects in the field of road transport NVH.

Sixteen members of EARPA form this task force 1 , with expertise in all major fields of automotive NVH

research integrating the key elements of the road transport system – the vehicle, the infrastructure and

the user.

This position paper presents an overall synthesis of the task force members’ view: the relevance of

research and technological development (RTD) on NVH of automotive vehicles, the definition of related

boundary conditions and RTD suggestions for the current (FP7) and next Framework Programme of the

European Union and further research programmes. From the independent research providers’ perspective,

four major research areas were identified:

• new noise and vibration reduction technologies for propulsion systems and vehicles with low CO 2

emission, considering light-weight design, smart systems and novel materials

• research in specific NVH behaviour of electrified vehicles particularly for urban transport

• specific research in tyre-road noise with focus on electric vehicles, heavy duty vehicles and urban

transport

• further advancing and extending of simulation tools and models for improved concept modelling and

for higher prediction accuracy of noise and vibration generated by conventional, hybrid and fully

electrified road transport

2. RELEVANCE AND IMPORTANCE OF RTD ON NOISE, VIBRATION AND HARSHNESS OF VEHICLES

Noise, vibration and harshness (NVH) as a field of vehicle technology has two different scopes: firstly,

interior NVH aspects which include the improvement of the interior vibro-acoustic environment for the

drivers and passengers and the protection against occupational health issues for the professional vehicle

driver and, secondly, exterior NVH aspects aiming at the control and reduction of environmental noise

emission by road vehicles but aiming also at a sufficient acoustic noticeability of electric vehicles (EV) at

low speeds for the safety of vulnerable road users.

The objectives within the first scope are determined by market needs and have achieved great progress

over the last twenty years. In view of the new challenges of CO 2 reduction with the future propulsion

1

Members of EARPA TF NVH:

AIT, AVL, CIDAUT, FEV, FhG-LBF, IDIADA, IKA, K.U. Leuven, LMS, Ricardo, SP, Tecnalia, TNO,

TUE, UNIFI-DMTI, UPV-CMT

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European Automotive Research Partners Association aisbl

36-38 Rue Joseph II B-1000 Brussels, Belgium

Tel +31 888 668 287 Fax +31 15 269 21 11

systems, it is important to maintain the current comfort levels under the new boundary conditions imposed

by the alternative drives in order to ensure the competitiveness of the European automotive industry.

The second scope is mostly determined by the social concern about environmental issues. Environmental

noise emission is an attribute of the vehicle that cannot be perceived and assessed by the vehicle driver

and is therefore governed not by market needs, but by governmental and EU regulations.

Over the last ten years noise impact from road vehicles has been a point of special interest in the field of

the environmental effects of road transport. According to the communication “Greening Transport” 2

32 % of the EU’s population is affected by noise and that at least one million healthy life years are lost

every year from traffic related noise in the western part of Europe 3 . Important counteracting initiatives

were taken over the last ten years:

• Directive 2002/49/EC on the assessment and management of environmental noise

• Amendment to the Directive 70/157/EEC on the permissible sound level of motor vehicles

• Amendment to the Directive 92/24/EC relating to the components and characteristics of two- and

three-wheeled motor vehicles

• Proposal for a regulation concerning type approval requirements for the general safety of motor

vehicles (including tyre-road noise emission) [COM (2008) 316]

• Within the consecutive EU Framework programmes many research projects aimed at development

of noise reducing technologies and noise assessment methods for road transportation noise were

executed (e.g. SILENCE, HARMONOISE, IMAGINE, SILVIA, QCITY, SIRUUS, INMAR, ROTRANOMO,

RATIN), as well as the CALM I and II network activities for the exchange of information and

development of noise abatement strategies

Despite all these actions and initiatives the growth of the traffic density and of the number of vehicles in

use will continue. Therefore the total noise impact from road traffic is expected to rise further in the

coming years. Noise emissions per vehicle in each vehicle class have decreased slightly as a result of type

approval regulations and EU framework research efforts, but trends towards heavier vehicles and

developments in vehicle technology (e.g. wider passenger car tyres) have more or less neutralised the

effect of the noise emission reductions on a fleet average level.

Further development of low noise and vibration technology in vehicle design and construction will be

needed to achieve a significant reduction of the noise emission per vehicle, and therefore of the total noise

impact of road transport. In recent years the attention for noise as an environmental issue seems to have

shifted towards the problem of climate change and the related ambition to reduce the energy consumption

of road vehicles. New developments in vehicle technology emerge: reduction of vehicle weight by the use

of lightweight materials, downsizing of engines and the accelerated introduction of hybrid and electric

vehicles. These trends will have definite influences, both positive and negative, on the NVH characteristics

of vehicles. Therefore continuous research efforts will be needed, aiming at

• an improved understanding of the relations between vehicle design, driving patterns and noise

emission,

• the development of measures to further control and reduce the noise emission,

• ensuring a good vibro-acoustic interior environment to strengthen the competitiveness of the

European automotive industry.

3. BOUNDARY CONDITIONS FOR RTD ACTIVITIES IN THE FIELD OF NVH

Due to the high environmental impacts of transport such as CO 2 emission, local air and noise pollution and

consumption of fossil energy resources, the activities for achieving green and sustainable transport have

high priority 4 and need to be supported by further advanced and new technologies. Thus, research for

2

3

4

SEC(2208) 2206: Commission Staff Working Document on Greening Transport, Brussels, 8.7.2008.

WHO (2011): Burden of disease from environmental noise - Quantification of healthy life years lost in Europe

COM(2008) 433 final: Greening Transport, Brussels, 8.7.2008

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European Automotive Research Partners Association aisbl

36-38 Rue Joseph II B-1000 Brussels, Belgium

Tel +31 888 668 287 Fax +31 15 269 21 11

reducing transport noise also has to consider all the other aspects of greening the European transport and

its consequences. In addition, it must take into account the economic and market situation.

In EARPA’s view, the primary boundary conditions for research and technological development (RTD) in

road transport NVH are:

• compatibility with emission reducing and energy saving technologies (e.g. low friction, light-weight

design, down-sizing of engines)

• consideration of alternative propulsion systems (e.g. hybrids, electrification, range extenders, fuel

cells)

• safety aspects (e.g. electric vehicles too quiet for pedestrians, wet grip of low-noise tyres,

low/uncommon system feedback to drivers)

• cost competitiveness (e.g. in comparison with conventional power trains and vehicles)

• new mobility requirements

• ecologically friendly technologies (e.g. the use of natural light–weight materials, recyclability)

4. RESEARCH NEEDS AND SUGGESTIONS FOR EUROPEAN RESEARCH PROGRAMMES

Greening the European transport system requires vehicle manufacturers to adapt a new way of developing

vehicles. Power train and transmission systems are in a fundamental change (electrification, hybrid etc.),

and vehicles and engines must be scaled down to reduce weight, cost and fuel consumption. At the same

time, the current high levels of other vehicle attributes such as safety, NVH and reliability have to be

maintained. In addition, quality and efficiency of development and production must be improved, to

achieve vehicles that are not only clean, safe and reliable, but also competitive in the end.

This necessitates adaptations and supplements in the research needs of previous research agendas 5,6

leading to updated or new research papers 7,8 .

Under consideration of the primary boundary conditions as described above, the EARPA NVH Task Force

sees the following four major fields of NVH research needs:

A. New noise and vibration reduction technologies for propulsion systems and vehicles with

low CO 2 emission, considering light-weight design, smart systems and novel materials

Low noise technologies for light-weight design of both propulsion systems and vehicle structures

Development/adaptation of novel acoustic materials (such as high damping materials, metal or other

structural foams, meta-materials etc.), in particular for use in urban road transport

Development of smart systems for improved NVH behaviour (e.g. piezo-electric actuators for active

vibration/noise cancellation) and their integration into the vehicle

B. Research in specific NVH behaviour of electrified vehicles particularly for urban transport

Investigation of the noise behaviour of electrified propulsion systems and identification of the related

NVH requirements and achievable targets including sound quality aspects and customers noise

perceptions

Noise reduction technologies for NVH critical elements of electrified propulsion systems such as electric

motor, electric converters, range extender unit, cooling system, air supply and compressor of fuel cells

Noise performance of electrical auxiliary aggregates of (electrified) freight vehicles

5

6

7

8

ERTRAC Strategic Research Agenda Overview, Oct. 2004 (www.ertrac.org)

CALM Strategy Paper: Research for a Quieter Europe in 2020, Sep. 2007

ERTRAC Strategic Research Agenda 2010, Executive Summary and Technical Document, Oct. 2010 (www.ertrac.org)

EARPA General Position Paper 2010: A Vision for Integrated Road Transport Research, Nov. 2010 (www.earpa.eu)

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European Automotive Research Partners Association aisbl

36-38 Rue Joseph II B-1000 Brussels, Belgium

Tel +31 888 668 287 Fax +31 15 269 21 11

Noise reduction technologies for the auxiliary units of hybrid and electric vehicles such as A/C

compressor, power steering pump, cabin heater etc.

Investigation on the need of a minimum noise emission from electrified vehicles for safety reasons

C. Specific research in tyre-road noise with focus on electric vehicles, heavy duty vehicles and

urban transport

Investigation of tyre-road noise generation of electric vehicles and heavy duty vehicles especially in

urban traffic under steady and transient driving conditions (such as braking, curves, acceleration etc.)

Quiet road surfaces dedicated to urban areas for less generation of tyre-road noise and reduction of

noise propagation to surrounding (residential) areas

D. Further advancing and extending of simulation tools and models for improved concept

modelling and for higher prediction accuracy of noise and vibration generated by

conventional, hybrid and fully electrified road transport 9

Improvements in concept modelling and simulation for providing reliable NVH concept and design

aspects in early design stages (enabling more efficient frontloading of the design engineering process)

Improved modelling of the actual dynamic source loading and the most relevant damping mechanisms

(including non-linear effects)

Extension of current NVH simulation methodologies to the mid-frequency range for conventional,

hybrid and fully electrified vehicles

Adaptation of models for coupling computational fluid dynamics (CFD) with acoustic approaches for

reliable prediction of flow-induced noise and vibration (e.g. in intake and exhaust systems, wind noise

etc.)

Extension of models for noise and vibration prediction of alternative propulsion systems

Extension/adaptation of prediction models for the behaviour of advanced acoustic materials such as

multi-layer trim components, novel light-weight structures, meta-materials, visco-elastic materials etc.

Further advancing of probabilistic methods to treat uncertainty and variability effects on the dynamic

response, in particular for use in large (vehicle) NVH models

Development of modelling paradigms for sound engineering of new generation transport vehicles

(e.g. modelling for sound quality)

The EARPA Task Force NVH sees the requirement to carefully identify research topics on a European level

in close co-operation with all relevant stakeholders. Taking advantage of their expertise, EARPA members

can offer support to this identification process on a neutral basis. Moreover, EARPA invites all stakeholders

to discuss the above research issues with the Task Force NVH.

CONTACT:

The EARPA Noise Vibration & Harshness Task Force

NVH TF Chairman

Bert Pluymers, K.U. Leuven

Tel: +32 (0) 16 32 24 80

bert.pluymers@mech.kuleuven.be

More information on EARPA at: www.earpa.eu

NVH TF Secretary

Manfred Haider, Austrian Institute of Technology

Tel: +43 (0) 50 550 6256

manfred.haider@ait.ac.at

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compare also EARPA Position Paper: The Key Role of Modelling & Simulation, Oct. 2010 (www.earpa.eu)

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