Your strong partner for NVH testing

For more than 15 years, ATESTEO has offered reliable noise, vibration, and harshness (NVH) testing in test benches. At the largest independent European testing centre for drivetrains, our headquarters in Alsdorf, Germany, we test your transmissions during development for audible and tangible vibrations. With our own key equipment for testing powertrains and a total of three of our own NVH component test benches, an acoustics dynamometer, and a test track, we assist you to identify NVH phenomena early and to optimise your transmissions during development.

NVH – Noise, vibration, harshness

Noise, vibration, and harshness, or NVH for short, are terms that describe audible (noise) or tangible (vibration) vibrations in vehicles. Harshness is the rough transmission of vibrations, felt as a sudden tremor, in the speed range of the motor from 20 to 100 Hertz. Minimising these vibrations such that the end consumer in the vehicle no longer perceives them as disturbing is a major aim during the development of the drivetrain. NVH testing enables early recognition of NVH phenomena, which can then be avoided early during the development stage of the powertrain. This later makes driving in the production vehicle more comfortable and serves to avoid complaints and a loss of image.

NVH testing: vibration measurements and vibration reduction at test benches

Enabling the recognition of NVH phenomena early during development; thus, avoiding them in later standard production vehicles, is the aim of ATESTEO’s NVH test benches. This is accomplished by frontloading the NVH issues during development of the transmission and system. Besides the test bench which has been running for 15 years, ATESTEO now offers two new Class 1 NVH test benches in accordance with ISO 3745, on which both FWD and AWD transmissions may be tested. Our new NVH test benches permit NVH testing of all forms of transmissions, and are set up for the special needs of electric and hybrid drives. An additional electric machine (permanent magnet motor) may be employed to enable HIL (Hardware in the Loop) testing.

Range of services at our new NVH test benches

Conventional NVH tests

Engine torque pulsation simulation drive

Rattle and howling tests

Background noise <35 dB(A)

Start-stop simulation

Sound pressure and sound power measurements from 150 Hz to 16,000 Hz

HIL testing

Highly dynamic tests under real operating conditions

Substitution of simulation models for real mechanics

Real-time rest bus simulation to control the machines

Low inertia values

Testing of e-axles and hybrid drive systems

Electric motors with high torques are used

Speeds of up to 20,000 rpm

Low noise emissions

Battery simulator for e-motors

Power meter for measuring efficiency

Components are balanced during operation

Component testing

Highly dynamic machines to test components such as dual-mass flywheels, transmissions (gear units), or rear axles

Rapid control of the drive units with 6 kHz

Tests of e-motors and vehicle inverters

Hollow shaft machine for providing drive with a coaxial construction

Layout of the new test benches

Click on the graphic to enlarge

The new test benches feature a modern, high-tech layout. The input drive is, for example, performed by a hollow shaft, which enables testing state-of-the-art coaxial transmissions. To avoid influences of the swiftly rotating input motor on measurements, the input motor is decoupled from the rest of the test bench by pneumatic springs. Likewise, the corresponding swiftly rotating drive shafts are supplied with a balance quality of 2.5G.

Technical data of the new NVH test benches

NVH cell data

Class 1 NVH cell in accordance with ISO 3745

Sizes of test objects up to 500 mm x 800 mm

Frequency range: 150–16,000 Hz

Background noise: <35 dB(A)

Technical data of the input machine with hollow shaft

Torque: 575 Nm

Rotation: 20,000 rpm

Acceleration: 4,000 rad/s2

Simulation possibilities

of pulsation of the engine torque (ETPS drive)

of the drivetrain and its components

of the vehicle battery

HIL testing with additional permanent magnet (PM) motor

NVH testing for electric drive systems

The development of hybrid and electric vehicles involves new challenges for the development of NVH testing. We have taken these into account and met them when developing our new NVH test benches.

Because of the properties of electric drives, new demands on the drives of NVH test benches arise, such as low vibration response or a low system response up to speeds of 20,000 rpm and low noise emission. We respond to these challenges with comprehensive new developments as follows:

NVH drive unit

Reinforced, preloaded, high balance quality, and filter

> Low vibration excitation

Mount for drive and test object

High natural frequencies and dampening materials

>Low system responses

Motor sheathing

Curved, covered, and with double-walled insulation

> Sound emission < 35 dB(A)

Array of microphones for measuring sound

Fully automated for high reproducibility and quickly changing out the test object

NVH testing for hybrid drive systems

For testing electric and hybrid drive systems, it is possible to simulate the correspondingly necessary components of the electric or hybrid vehicle in the NVH test bench. First and foremost, battery simulators are required.

Click on the graphic to enlarge

HIL testing on the NVH test bench

The new test benches are equipped not only for NVH analysis, but also for HIL testing. By using an additional permanent magnet (PM) motor, hardware in the loop simulations may be conducted directly on the ATESTEO test bench. HIL involves testing individual components by substituting a simulation model for the real mechanics and constructing a realistic test environment for the test object.

Click on the graphic to enlarge

Pass-by noise (PBN) measurements in accordance with DIN ISO 362

At the ATESTEO proving grounds (test track), we can conduct outdoor pass-by noise measurements when the vehicle is driving past under acceleration, in accordance with DIN ISO 362 and according to the new guideline R 51. The vehicle to be tested approaches the measuring site at a constant speed, then accelerates with a wide-open throttle while entering the site until the rear of the vehicle has left the measuring site. During this accelerated pass-by, the sound pressure levels on both sides of the vehicle and the vehicle speed are recorded and analysed. The test track surface is prepared in accordance with DIN 10844 and adapted to the needs of heavy-duty vehicles.

Considerable development expertise

Drivetrain simulation

ATESTEO has the know-how and technical facilities to conduct complex simulations; for example, those of the powertrain. This great expertise also flows into the development of new test benches.

Click on the graphic to enlarge

Frontloading during the development phase

Employing NVH test benches enables the frontloading of NVH testing during the development process. Through using corresponding analysis software, NVH phenomena such as gear whining become visible.

Click on the graphic to enlarge

The ATESTEO expert teams for your NVH testing challenges

We offer you a wide range of services and expertise in the field of NVH testing. Three NVH teams in Alsdorf, Germany support the following fields of activity:

 

Click on the graphic to enlarge

Download

All further information on test bench-based vibration testing as well as NVH measurements on the entire vehicle at ATESTEO can be found in our current performance brochures.

Download NVH Vibration Testing
Download NVH Measurement Vehicle

Would you like to know more about the services and advantages we offer in the field of NVH testing?

Your personal ATESTEO contact will be pleased to assist you.

+49 2404 9870 0
nvh-testing@atesteo.com