Perfect sound for Electric Vehicles
The electric drives make our vehicles significantly quieter – both for those sitting inside and those passing by outside. This change poses new challenges in terms of acoustics: Noises that had previously been drowned out by the sound of a combustion engine have now become a source of irritation. These kinds of noise can crop up in lots of places on electric vehicles and are mainly produced by auxiliary units and sub-systems. The highest-performance auxiliary unit in an e-vehicle is the air-conditioning compressor, which is built into in the cooling circuit as a vehicle sub-system.
Acoustic Engineering for Vehicle Development
IPETRONIK's acoustic engineering team offers all-round expertise and extensive experience in this field of technology, amassed from a wide range of projects. Their focus is in developing methodology and in supporting the series development of hybrid and e-vehicles.
The IPETRONIK engineering facilities in Eichstätt and in Baden-Baden house a wide selection of test bench resources. These include several acoustic testing chambers large enough for entire vehicles – they can create a conditioned environment of between -20°C and +50°C, can control relative humidity and can simulate solar radiation of up to 1200 W/m2. Units such as the air-conditioning compressor and various other vehicle sub-systems can be built and operated on the relevant test benches.
Our Service Portfolio
- Climate Acoustic Chamber for complete Vehicle
- Evaluation of Sources and Transfer Paths
- Unit and component acoustics
- Ventilation Acoustics
- Acoustic Chamber with 350 kW Charging Column
- Development Partnership
- Concepts for mounting and decoupling of Auxiliary Units
- Acoustic Simulation
Key Development Methodologies
- Consistent concept of sensors, measurement and analysis technology at the relevant interfaces regarding vibration, dynamic force, gas pulsation or airborne noise as well as hardware modules, data loggers and software
- Authentic operating concept at component level analogous to typical vehicle operation
- Close comparison of actual status, development goals and specification values
- Combination of design (CAD), simulation (structural and gas dynamics, airborne sound radiation) and testing
Acoustic chamber with HV Charging Column
- Integrated 350 kW DC charging column for vehicle testing (Baden-Baden location)
- Measurement/display of standard charging processes (AC up to 22 kW) and higher power classes
- Measurement documentation of the charging processes with regard to all relevant parameters
- Quantification of charging power influence on the external noise emitted by the vehicle
Comprehensive NVH Testing
The resources available at IPETRONIK's Baden-Baden facility for the NVH test of the fast charge facilitate comprehensive evaluation and optimisation of development agents with regard to hardware and operating strategy.
Alongside the general NVH development methods, such as the multi-channel data acquisition for identifying impulses and transmission paths, IPETRONIK has established other specialist processes. These include psychoacoustic evaluation, the blind test with test subjects and other methods, such as locating the source of a noise using acoustic cameras (GFAI) or laser vibrometry (Polytec).
Find the right solution!
Climate Acoustic Chamber
The climate-acoustic chamber with its flexible conditioning from cold to heat climate offers ideal boundary conditions to realistically load the heating/air conditioning system of a vehicle. With the control of the temperature from -20°C to +50°, the humidity, the sun simulation by means of infrared lamps as well as the vehicle inflow with up to 32 km/h driving wind, a variety of climate zones can be simulated as vehicle environment. In addition to the thermodynamic usability, the design as an acoustic semi-free-field room together with the hydrophobic attenuation of all conditioning components allows the authentic evaluation and measurement of acoustic phenomena. Typical applications include the testing and subjective evaluation of in-vehicle air conditioning compressors, HVAC noise (evaporator hiss) and general transfer path analysis of the refrigeration circuit.
HV Charging Column Acoustic Chamber
The acoustic chamber with HV charging column offers a wide range of possibilities for acoustic testing of vehicles, vehicle subsystems and general technical superstructures. Designed as a semi-open-air room with large hinged doors on two sides, the acoustic chamber has a vehicle lifting platform that allows very flexible control and modification of test setups already being tested. The combination of HV charging station and acoustic environment supports tests and development steps, as recently demanded in automotive engineering with purely electric vehicles and fast charging technology.
The acoustic development of automotive components benefits significantly from the interaction of testing and simulation. While general experience and analyses of measurements form the basis for new developments, simulation allows the evaluation of components and concepts in advance, independently of time- consuming and cost-intensive hardware. Thus, it is possible to select from several designs, weak points can be identified and avoided at an early stage. Thus, the parallel management of simulation and testing allows a constant mutual optimization - the quality of each hardware construction stage benefits from the previous simulation; likewise, the accuracy of the simulation models can be optimized by comparison with the subsequently available measurement data.
Services with the Acoustic Camera
As is well known, multi-channel microphone measurements allow the evaluation of sound propagation at different positions. This allows conclusions to be drawn about different assemblies and their acoustic radiation behavior. However, the spatial resolution when using conventional microphones is limited and the exact assignment of where a sound is actually emitted is often very inaccurate. Here, the use of the acoustic camera offers a practical and fast possibility for the identification of dominant partial sound sources. Using a ring-shaped arrangement of 48 individual microphones (microphone array) and a video camera in the center of the ring, the sound radiation is initially recorded synchronously with the video image data. The analysis of the different propagation times of the sound radiation of individual partial sources allows the directional assignment of their radiation points.
NVH System Acoustics Test Bench
With its NVH system test bench, IPETRONIK offers the possibility of recording and analyzing the noise development at the HVAC (air conditioning unit) using in-house acoustic measurement technology. For this purpose, microphones are placed in the near field of local sound sources and, if necessary, the so-called acoustic camera (GFAI, see figure on the right) is used for sound localization. Sensors for vibration and pulsation of the refrigerant can also be placed in the system.
Starting with consulting and system procurement, we take over the entire project management. We install the measurement technology, including cabling and the complete application of sensors and actuators. Configuration and data evaluation are just as much part of the scope of services as calibration, functional testing and subsequent dismantling of the test vehicles. A modern technology center and an experienced team of application engineers and mechanics are available specifically for this purpose. In the course of the steadily growing importance of hybrid systems and electric vehicles, we have developed our own high-voltage hardware solutions for current, voltage and temperature. These allow all relevant measured variables to be recorded via IPEmotion or our CAN bus data logger. They can also be integrated into existing CAN bus systems. In the context of the development of hybrid systems and electric vehicles, these are becoming increasingly important. Thanks to TÜV certification of our HV measurement technology as well as continuous further education and regular training in the high-voltage field, we guarantee the highest level of quality and safety. A separate area is available for the safe upgrade of electric and hybrid vehicles.
Quiet Air Test Bench
With the Quiet Air Test Bench, IPETRONIK offers the possibility of testing air-flow systems and components. The Quiet Air Test Bench has established itself as a multifunctional tool for testing vehicle ventilation. The focus here is on aeroacoustic and flow-physical issues. The compactness and mobility of the test bench allow the realization of various test architectures from standardized to specific setups. The in-house developed test rig is used solo, but also in combination with other test equipment. Acoustic chambers and climatic-acoustic chambers are available for aeroacoustic tests.