Automotive Acoustics Conference 2019: 5. Internationale ATZ-Fachtagung Fahrzeugakustik
()
Über dieses E-Book
Der Tagungsband zur ATZlive-Veranstaltung „Automotive Acoustics Conference 2019“ befasst sich mit technischer Akustik und NVH, welche zu den wichtigsten Indikatoren für Fahrzeugqualität und -verarbeitung gehören. Mit den grundlegenden Veränderungen der Antriebstechnik rücken diese Aspekte daher zunehmend in den Fokus der Automobilforschung und -entwicklung. Fahrzeugarchitekturen, Antriebssysteme und Designgrundsätze werden aufgrund der weltweiten Emissionsgesetzgebungen, die energieeffiziente Fahrzeuge fördern, einer kritischen Betrachtung unterzogen. Schon in sehr naher Zukunft muss die gleiche oder eine höhere NVH-Performance durch Leichtbaustrukturen, kleinere Motoren mit Turbolader oder alternative Antriebsstränge erreicht werden. Die internationale Automotive Acoustics Conference bietet hierfür ein wichtiges globales Forum für den Wissens- und Meinungsaustausch.
Ähnlich wie Automotive Acoustics Conference 2019
Ähnliche E-Books
21. Internationales Stuttgarter Symposium: Automobil- und Motorentechnik Bewertung: 0 von 5 Sternen0 BewertungenExperten-Forum Powertrain: Simulation und Test 2019: Vom Prüfstand bis Big Data - ganzheitliche Validierung-in-the-Loop Bewertung: 0 von 5 Sternen0 BewertungenElektronik in der Fahrzeugtechnik: Hardware, Software, Systeme und Projektmanagement Bewertung: 0 von 5 Sternen0 BewertungenGrundlagen Verbrennungsmotoren: Funktionsweise und alternative Antriebssysteme Verbrennung, Messtechnik und Simulation Bewertung: 0 von 5 Sternen0 BewertungenZuverlässige Bauelemente für elektronische Systeme: Fehlerphysik, Ausfallmechanismen, Prüffeldpraxis, Qualitätsüberwachung Bewertung: 0 von 5 Sternen0 BewertungenEinsatz der Blockchain-Technologie im Energiesektor: Grundlagen, Anwendungsgebiete und Konzepte Bewertung: 0 von 5 Sternen0 BewertungenLeitfaden Safety of the Intended Functionality: Verfeinerung der Sicherheit der Sollfunktion auf dem Weg zum autonomen Fahren Bewertung: 0 von 5 Sternen0 BewertungenEMSR-Stellenplan: Symbolik und Übergang von DIN 40719-2 zu DIN EN 81346-2 Bewertung: 0 von 5 Sternen0 BewertungenBussysteme in der Fahrzeugtechnik: Protokolle, Standards und Softwarearchitektur Bewertung: 0 von 5 Sternen0 BewertungenSchriftenreihe des Fachbereichs Informatik der Fachhochschule Dortmund: Band 3 Bewertung: 0 von 5 Sternen0 BewertungenEnergie für nachhaltige Mobilität: Trends und Konzepte Bewertung: 0 von 5 Sternen0 BewertungenMesstechnik und Prüfstände für Verbrennungsmotoren: Messungen am Motor, Abgasanalytik, Prüfstände und Medienversorgung Bewertung: 0 von 5 Sternen0 BewertungenLeitfaden Automotive Cybersecurity Engineering: Absicherung vernetzter Fahrzeuge auf dem Weg zum autonomen Fahren Bewertung: 0 von 5 Sternen0 BewertungenHydraulik – Fluid-Mechatronik: Grundlagen, Komponenten, Systeme, Messtechnik und virtuelles Engineering Bewertung: 0 von 5 Sternen0 BewertungenElektromobilität und Sektorenkopplung: Infrastruktur- und Systemkomponenten Bewertung: 0 von 5 Sternen0 BewertungenKosteneffiziente und nachhaltige Automobile: Bewertung der realen Klimabelastung und der Gesamtkosten – Heute und in Zukunft Bewertung: 0 von 5 Sternen0 BewertungenDubbel Taschenbuch für den Maschinenbau 2: Anwendungen Bewertung: 0 von 5 Sternen0 BewertungenElektromobilität: Grundlagen einer Zukunftstechnologie Bewertung: 0 von 5 Sternen0 Bewertungen3D-Druck beleuchtet: Additive Manufacturing auf dem Weg in die Anwendung Bewertung: 0 von 5 Sternen0 BewertungenVerkehrsmanagementzentralen für Autobahnen: Aktuelle Entwicklungen aus Deutschland, Österreich und der Schweiz Bewertung: 0 von 5 Sternen0 BewertungenGasmesstechnik in Theorie und Praxis: Messgeräte, Sensoren, Anwendungen Bewertung: 0 von 5 Sternen0 BewertungenIndustrielles Luftfahrtmanagement: Technik und Organisation luftfahrttechnischer Betriebe Bewertung: 0 von 5 Sternen0 BewertungenDatenanalyse, Abstimmung und Entwicklung Bewertung: 0 von 5 Sternen0 BewertungenDiesel – eine sachliche Bewertung der aktuellen Debatte: Technische Aspekte und Potenziale zur Emissionsreduzierung Bewertung: 0 von 5 Sternen0 BewertungenDubbel Taschenbuch für den Maschinenbau 3: Maschinen und Systeme Bewertung: 0 von 5 Sternen0 BewertungenSensoren für die Prozess- und Fabrikautomation: Funktion – Ausführung – Anwendung Bewertung: 0 von 5 Sternen0 BewertungenSchwingungen mechanischer Antriebssysteme: Modellbildung, Berechnung, Analyse, Synthese Bewertung: 0 von 5 Sternen0 BewertungenBussysteme in der Automatisierungs- und Prozesstechnik: Grundlagen, Systeme und Anwendungen der industriellen Kommunikation Bewertung: 0 von 5 Sternen0 BewertungenDie Brennstoffzelle: Eine technische und logistische Betrachtung sowie deren Anwendung im ÖPNV Bewertung: 0 von 5 Sternen0 BewertungenSystem Lifecycle Management: Digitalisierung des Engineering Bewertung: 0 von 5 Sternen0 Bewertungen
Automobil für Sie
Der ultimative Bike-Workshop: Alle Reparaturen, Kaufberatung, Profi-Tipps Bewertung: 0 von 5 Sternen0 BewertungenDeutsche Autos: Die schönsten Modelle seit 1945 Bewertung: 0 von 5 Sternen0 BewertungenDas Busbastler Academy Handbuch: Schritt für Schritt zum eigenen Campervan Bewertung: 0 von 5 Sternen0 BewertungenDer Europäische Führerschein: Oder ohne MPU in die Freiheit !!! Bewertung: 0 von 5 Sternen0 BewertungenPraxisratgeber Klassikerkauf Mercedes-Benz 190 (W 201): Alle Modelle von 1982-1993 Bewertung: 0 von 5 Sternen0 BewertungenE-Auto einfach erklärt: Von A wie Akku bis Z wie zu Hause laden Bewertung: 0 von 5 Sternen0 BewertungenVan it Yourself!: Ausbautipps für deinen Camper – von Bus bis Sprinter Bewertung: 0 von 5 Sternen0 BewertungenFahr Rad!: Alles über Kauf, Ausrüstung, Fahrtechnik und Reparaturen Bewertung: 0 von 5 Sternen0 BewertungenFührerscheinverlust und MPU (3. Auflage): Erfolgreich durch die Medizinisch Psychologische Untersuchung. 3. Auflage 2020 Bewertung: 0 von 5 Sternen0 BewertungenFast alles über Opel: Ein Sammelsurium Bewertung: 0 von 5 Sternen0 BewertungenWohnwagen, Wohnmobil oder Wohnbus?: Freiheit die ich meine..... Bewertung: 0 von 5 Sternen0 BewertungenDas Vespa Schrauberhandbuch: Reparieren und Optimieren leicht gemacht. Smallframe-Modelle (1965 - 1989) Bewertung: 0 von 5 Sternen0 BewertungenPedelecs, E-Bikes selber bauen: Greifen Sie zum Werkzeug und bauen Sie Ihr eigenes Pedelec! Bewertung: 0 von 5 Sternen0 BewertungenKleine Hubschrauberschule: Fliegen leicht gemacht Bewertung: 0 von 5 Sternen0 BewertungenMit dem Fahrrad ins Büro: Alles, was Fahrradpendler wissen sollten Bewertung: 0 von 5 Sternen0 BewertungenFeuerwehr: Die spektakulärsten Einsatzfahrzeuge Bewertung: 0 von 5 Sternen0 BewertungenPraxisratgeber Klassikerkauf Porsche 911 (964): Alle Modelle 1989 - 1994 Bewertung: 0 von 5 Sternen0 BewertungenVerkehrsflugzeuge: Das aktuelle Typentaschenbuch Bewertung: 0 von 5 Sternen0 Bewertungen101 Dinge, die man über E-Autos wissen muss Bewertung: 0 von 5 Sternen0 BewertungenMofas und zweirädrige Kleinkrafträder bis 25 km/h Bewertung: 0 von 5 Sternen0 BewertungenVolkswagen Käfer: läuft und läuft ... seit 75 Jahren Bewertung: 0 von 5 Sternen0 BewertungenDas E-Bike: Technik, Modelle, Praxis für Pedelecs und Elektrofahrräder Bewertung: 0 von 5 Sternen0 BewertungenDie PS-Dynastie: Ferdinand Porsche und seine Nachkommen Bewertung: 0 von 5 Sternen0 BewertungenDas große Buch der Lederpflege: Schuhpflege - Bekleidung - Möbelpflege Bewertung: 0 von 5 Sternen0 Bewertungen101 Dinge, die man über die Raumfahrt wissen muss Bewertung: 0 von 5 Sternen0 BewertungenDie Tesla-Methode: 7 Prinzipien, die Ihr Unternehmen fit für die Zukunft machen Bewertung: 0 von 5 Sternen0 BewertungenE-MTB: Wartung, Pflege & Reparatur: Sitzposition, Motor, Schaltung, Bremsen, Federung, Laufräder Bewertung: 0 von 5 Sternen0 BewertungenDas Automobil und seine Geschichte: vom einfachen Karren zum modernen Automobil Bewertung: 0 von 5 Sternen0 BewertungenEin Fahrlehrer packt richtig aus!: Über die Gefahren im Straßenverkehr und wie wir alle besser werden können Bewertung: 5 von 5 Sternen5/5VW Bus T3: Alle Modelle 1979-1992 Bewertung: 0 von 5 Sternen0 Bewertungen
Verwandte Kategorien
Rezensionen für Automotive Acoustics Conference 2019
0 Bewertungen0 Rezensionen
Buchvorschau
Automotive Acoustics Conference 2019 - Wolfgang Siebenpfeiffer
© Springer Fachmedien Wiesbaden GmbH, ein Teil von Springer Nature 2020
W. Siebenpfeiffer (Hrsg.)Automotive Acoustics Conference 2019Proceedingshttps://doi.org/10.1007/978-3-658-27669-0_1
NVH Refinement Issues for BEV
Léon Gavric¹
(1)
VP & Senior NVH Expert, Department of Quality and Engineering, PSA Groupe, Paris, France
Léon Gavric
Email: leon.gavric@mpsa.com
Abstract
Regulatory pressures on internal combustion engines (ICEs), combined with technological improvements in electric powertrains and batteries lead to an increase of demand for electric vehicles (EVs). Both, the traditional carmakers as well as new entrants without ICE legacies are developing and putting on the market new EV models.
Worldwide sales of pure battery EVs (BEV-excluding hybrids) grew by approximately 45% in 2016. Since, BEVs become mass-market product, it is necessary that automotive acoustic engineers apprehend and evaluate related technology trends and their influences on vehicle NVH. The BEV is a radically different vehicle and it needs an updated NVH approach, which targets all relevant NVH comfort issues in a specific electric environment. As demand rises, BEV technology and design will continue to evolve, and strategic challenges will follow. Established OEMs and their traditional suppliers will need to rethink their approaches to preserve their revenue and profitability.
The ZE driving implies silence
. Consequently, some NVH performances are to be increased for BEVs. The lack of IC engine noise masking exacerbates: the noises of different systems & devices, wind noise, rolling noise and tire hiss, etc. the corresponding NVH requirements are to be strengthened, comparing to the IC engine vehicles. The completely new, but crucial NVH challenge for BEV is to control e-Powertrain whining. Disturbing noises like squeak rattle and buzz, particularly in low noise BEV context are prohibited, too.
Keywords
Battery Electric VehiclesNVH performancesNVH design
1 Actual Market and BEV
1.1 Why do EOMs Invest Massively in BEV
Environmental, friendly car becomes societal objective due to: the ecological conscience of customer, the tax policy in favor of low consumption cars and CO2 reduction objectives imposed by EU legislation.
The ‘ecological conscience’ of consumer, the CO2 reduction imposed by legislation and the low consumption tax policy adopted by majority of countries, motivate car manufacturers to develop new generation of low CO2 emission cars.
Concerning the CAFE The reduction of CO2 emission is required by new European legislation. The objectives are fixed by CAFE index: Corporate Average Fuel Economy
and expressed as quantity of CO2 generated by average car in grams per kilometer. The averaging is performed on total car ensemble sold in all European countries by a manufacturer. The non-respect of the objectives fixed by EU will lead to financial penalties proportional to the observed deviation. By 2021, phased in from 2020, the fleet average to be achieved by all new cars is 95 g of CO2 per kilometer (4.0 L/km). From 2019, the penalty will be €95 form the first gram of exceedance. The low emission BEVs will count double when compute the average. Moreover the percentage of low emission vehicles (BEV and PHEV) is imposed for the years to come (2025 xx% and 2030 XX%). Therefore, BEV technology seem to be unavoidable in order to reach those objectives.
CO2 emissions from new cars should be cut by 45% by 2030 and market uptake of zero – and low-emission vehicles should accelerate, said committee MEPs on Monday.
Environment Committee MEPs proposed setting a higher target for reducing EU fleet-wide emissions for new cars by 2030: 45% (compared to the EU Commission’s 30%) with an intermediate target of 20% by 2025. The draft legislation also sets similar targets for new vans.
Manufacturers whose average CO2 emissions exceed these targets will pay a premium to the EU budget, to be used, inter alia, for up-skilling workers affected by changes in the automotive sector, MEPs agreed.
Carmakers will also have to ensure that zero- and low- emission vehicles – ZLEVs – (which emit less than 50 g CO2/km) have a 40% market share of sales of new cars and vans by 2030, and 20% by 2025.
1.2 BEV Technology
The principle of BEV is simple: an electric motor powered by a battery replaces the Internal Combustion Engine Vehicle (ICEV) and the tank, and the vehicle is plugged to a charging spot when the battery needs to be charged (Fig. 1).
../images/488964_1_De_1_Chapter/488964_1_De_1_Fig1_HTML.pngFig. 1.
BEV (Battery Electric Vehicle) vs ICEV (Internal Combustion Engine Vehicle): technology and principal devices needed for generation of motion and energy storage.
They have many advantages: they are highly efficient, do not produce tailpipe emissions which is beneficial for local air quality, they have good acceleration, can be charged overnight on low cost electricity produced by any type of power station, including renewables. However, despite these advantages, BEVs, also, face significant challenges. Electricity storage is still expensive and the charging of the battery is time consuming; this is why the range of these vehicles is limited (Fig. 2).
../images/488964_1_De_1_Chapter/488964_1_De_1_Fig2_HTML.pngFig. 2.
E-powertrain and battery pack are the principal subsystems needed for electric motion.
E-powertrin comparing to IC-powertrain
It is generally of lower mass and moment of inertia, which implies lower excitation by road induced vibrations. It has a high torque, which can be observed even at low motor speeds. This may excite some driveline modes, like tip-in / let-off
or sway mode. E-motors have a low torque irregularity. In electric drives, it is usually called torque ripple
and generally does not exceed few percent of overall torque (~5%).
E-motors for vehicle driveline have high rotational speeds (up to 15 000 rpm). Still the inertial forces are low since there is no linear moving of masses (like pistons, valves, etc.) and consequently no unbalanced inertial forces. E-powertrain does not have idle speed vibrations neither shake due to stop & start.
Battery pack capacity and platform issues
A specific or native
platform is needed for a high-performances and driving range of BEV. A clear gap is observed in driving range and interior space between models with native BEV platforms and those compatible with IC powertrain. Non-native or multi-energy BEV platforms force the battery into the awkward footprint of the existing IC powertrain vehicles. The battery pack in native BEV platforms, by contrast, can take a simple, rectangular shape, giving native BEVs up to twice the range—over 300 km per charge and up to approximately 400 km for the best performers, for today’s battery technologies. In addition, native BEVs achieve a larger interior space (up to 10% by regression line) for the same wheelbase compared with not only non-native counterparts, but also standard ICE vehicles in the same segment.
1.3 Why Do Peoples Like BEV (… When They Like It !)
BEV are really fun and easy to drive. Nothing in the car needs to gear up so when you step on the accelerator it just goes, and it accelerates fast and from any initial speed. Conversely, you can use your brakes a lot less while driving an electric car. Moreover the breaking recaptures power to feed back to the battery. Not only does this let you go farther without recharging but it’s very handy because all you have to do is lift your foot of the gas
pedal and the car will start slowing down by itself.
Electric cars are quiet. That can make them even dangerous around pedestrians. To combat this, the legislation imposes AVAS (Alerting Vehicle Acoustic System), a devise producing alerting sound at speeds below 20 mph. Even so, BEV is infinitely quieter than a ICE car would be. Without engine noise, even the base model sound system gives me clearer sounding music than in a ICE vehicle.
The most BEV manufactures insist on making different
looking cars. They are more stylish, look better and new. The driver of electric cars is definitely different
from others. While this is very subjective, but the electric
technology is often associated with the care for planet and to the lot of other positive values. Consequently, a BEV owner is considered as a green oriented, young spirit, altruist person. All these positive values increase the self-esteem of BEV owners resulting in a willingness to possess BEV.
2 Specific NVH Issues for BEV
2.1 E-motor Noise
Permanent Magnet Synchronous Motor PMSM is used for most of electrified vehicle powertrains. PMSM rotor is equipped with permanent magnets and it follow rotating magnetic field. For the simplest bi-polar
motor (one pair of poles) the rotation frequency is proportional to the stator current frequency. PMS motors with 4, 5 or 6 pole pairs equip the most electric powertrains. Higher number of poles implies proportional speed reduction for the same stator current frequency. The motor torque is proportional to the phase angle between the magnetic field and rotor – load angle. The sinusoidal current of varying frequency powering PMS motors is created using adequate electronic devices and PWM technique (Pulse Width Modulation). Pulse-width modulation (PWM), as it applies to motor control, is a way of delivering energy through a succession of pulses rather than a continuously varying (analog) signal. By increasing or decreasing pulse width, the controller regulates energy flow to the motor shaft.
Permanent magnet synchronous motor PMSM is used for most of electrified vehicle powertrains. The principal vibration excitation of PMS motors correspond to complex pattern of forces due to the magnetic flux and resulting Maxwell pressure. The forces change shape and intensity as function of time, while still being periodic. Both radial and tangential forces are to be accounted for, since both generate radial stator displacements. The Maxwell forces can be then developed into double Fourier series in time and space/angle domains and analyzed as the fundamental excitation components (Fig. 3).
../images/488964_1_De_1_Chapter/488964_1_De_1_Fig3_HTML.pngFig. 3.
Principal sources of e-whining are: e-motor, reduction gears and power electronics.
Electrical drives are typically quieter than their ICE counterparts, but with very different NVH characteristics. While the ICE has a broadband noise spectrum, the electrical machine causes single tones in the audible spectrum, which unfortunately often corresponds to the frequency band in which the human ear is most sensitive. Therefore, despite their lower overall noise level, EVs may be sensed more unpleasant compared with ICE powered vehicles. Reducing the audible noise of the EVs asks for the analysis of the acoustic behavior including the electromagnetic force excitation, structural dynamic behavior and sound transmission and radiation, from the component (electrical machine) to the subsystem (electrical drive) and system level (powertrain).
Principal sources of whining are: electric motor, speed reduction gears and power electronics. Design parameters important for NVH are: number of poles, phases and slots, rotor and stator design, type of winding and skewing, stiffness and resonant frequencies, transmission error and axe rigidity, gear tooth surface and machining, frequency of PWM – Pulse Width Modulation and current control. All these parameters influence: the efficiency, the torque and the power characteristics of e-driveline. Consequently, a trade-off between NVH and other performances is generally needed.
2.2 Road Induced Noise and Vibration in BEV
Noise and vibration excited by the road are more noticeable in BEV because there is no masking effect of the corresponding IC engine excitation.
The tire/rolling noise
of BEV is louder, since they are heavier due to the high battery mass. Such noise is not a emotional vector when driving but is pursued as a lack of acoustic insulation (quality). The tires impacts are at origin of the noise which is then can be attenuate (or amplified) by wheels, axles and overall vehicle.
The low-frequency vibrations
are also produced by contact between the tires and the road. If correctly designed, the car body suspension filter this excitation. The optimization of powertrain suspension and stiffness of the BIW can improve the road induced vibrations (Fig. 4).
../images/488964_1_De_1_Chapter/488964_1_De_1_Fig4_HTML.pngFig. 4.
Vehicle suspension behavior due to the road excitation for different frequency ranges.
In order to isolate ICE idle excitation the modal frequencies of powertrain on elastic mounts have to be lower than the principal excitation frequency. For example, the principal engine order of 4-cylinder engine is 2 i.e twice of crankshaft rotational frequency. Moreover, the high road excitation at very low frequencies and engine order 0.5 characteristic for 2 time piston engines should be avoided, too. Consequently, all the resonances of powertrain on elastic mounts should be inside these two frequency limits.
When e-powertrain is considered, there is no idle speed excitation by principal engine order. Therefore, the modal frequencies of e-powertrain on elastic mounts can be higher in order to avoid the road excitation. Still, the mounts have to attenuate the structure borne part of whining excitation. For this purpose, a specific double filtering via a sub-frame may be used. There is no the specific, well suited, architecture of suspension to be used for e-powertrains. The design results from a trade-off between: the maximizing the mount spacing in order to diminish the saturation of mounts due to quasi-static load and the minimizing the part length in order to avoid resonances which may amplify the whining excitation (Fig. 5).
../images/488964_1_De_1_Chapter/488964_1_De_1_Fig5_HTML.pngFig. 5.
Principal sources of e-whining are: e-motor, reduction gears and power electronics.
E-powertrain suspension system is platform dependent. The multi-energy
platform, developed from an existing ICE one, have to allows integration of both IC and e-powertrains. Generally, a modified pendulum
system is chosen for such platform, while for a native
electric vehicle a dedicated mounting system can be designed.
In both cases, electric motor can be elastically mounted on an adequate sub-frame. The sub-frame is then fixed to the vehicle by the supplementary bushings, ensuring excellent isolation of whining structure borne noise (HF vibration).
The low rolling noise, underlines the quietness of BEV driving. When rolling, the road surface and tire tread pattern excite wheel over a wide frequency range. The wheel transmits part of this excitation to the vehicle and causes rolling noise inside of the vehicle. Depending on the design, the wheel can whether: isolate and attenuate the vibrations or amplify them if the wheel resonances are excited. The high rim rigidity is very important for a low road induced rolling noise. Specific design of alloy rims having high resonances is observed on BEV. Moreover, the road excitation can be amplified by car body deformations due to the low frequency modes of car body structure (torsion and flexion).
2.3 Battery Pack and BIW Rigidity
The capacity of Body-in-White (BIW) to attenuate road-induced noise and vibration is generally evaluated using two simple criteria: static torsional stiffness and frequency of first torsional mode. Same type of engineering criterion can be established for flexural deformation.
The structural rigidity of multi-energy platform highly depends on battery pack stiffness and mass. As a general rule, battery pack increases the static stiffness due to the additional rigidity fixed to the structure but diminishes the principal torsional mode frequency due to the added mass. Nevertheless, if well designed, the multi-energy platform preserves an equal performance attenuation of road excitation in both versions ICEV and BEV (Fig. 6).
../images/488964_1_De_1_Chapter/488964_1_De_1_Fig6_HTML.pngFig. 6.
Battery pack fixed to the BIW increases the stiffness and decreases the resonant frequencies (torsion and flexion) due to the added mass.
Native BEV platforms maximize battery packaging and autonomy. As a rule, native platforms, compared to the multi-energy ones, have higher static torsional rigidity due to the battery pack stiffness and lower torsional frequency due to battery mass. An appropriate design of both, platform and battery-pack, can improve the attenuation of structure borne noise and vibration induced by road up to 4–5 dB in the frequency range of 50–500 Hz.
2.4 Acoustic Transparency and Insulation
Both, external traffic noise and driving generated noise are to be accounted for when designing NVH treatment of BEV. The lack of IC engine masking, increase the importance of insulation from the external noise. The noise of surrounding traffic is very penalizing for the customer acoustic comfort and overall impression of quality and market positioning of vehicle. Therefore, the vehicle have to be soundproof up to certain sound pressure level, which can be achieved by an appropriate (high) thickness of windshield and car glass, by sealing of car doors (no acoustic leakage) and by applying absorption material in the driver’s compartment (Fig. 7).
../images/488964_1_De_1_Chapter/488964_1_De_1_Fig7_HTML.pngFig. 7.
A performant insulation is important for BEV. Both external noise and nose generated by the vehicle have to be taken into account when design the acoustic treatment. The sealing in order to diminish acoustic leakage and corresponding transparency due to external noise.
During the benchmarking it is observed that the mass of NVH treatments in ICEV and BEV is approximatively the same, at least on multi-energy platforms where comparison is easy to do.
2.5 Noise of Auxiliaries and Other Devices
In the ICEV the IC engine drives accessories. In the BEV the different devices as compressors, pumps and fans are to be electrically driven. The noise of such devices is particular important, since exacerbated, without IC engine masking. Such a new type of accessory generates new type of NVH problems (whining, electric whistling etc) (Fig. 8).
../images/488964_1_De_1_Chapter/488964_1_De_1_Fig8_HTML.pngFig. 8.
BEV accessory is electrified and potentially represents high whining risk. Moreover, the lack of ICE engine masking results in more sever specifications for most of driving conditions.
The noise generated by the electrified accessory in not the only acoustic issue. Disturbing dysfunctional BSR noises (buzz, squeak and rattle) can result in a very low car positioning with respect to the perceived quality. Consequently, the NVH specification on system & device noise have to be strengthened, in order to take into account relative quietness of BEVs.
3 State of the Art and Concluding Remarks
Battery Electric Vehicles (BEVs), compared to classic internal combustion engine (ICE) vehicles, are fairly simple and easy to operate. The simplest powertrain architecture consists in a high voltage battery, an electric motor with power electronics controller and a single speed gearbox.
With zero tailpipe emissions, BEVs also offer a clean alternative to vehicles with ICEs by helping to reduce exposure to air pollution resulting from fuel combustion and limiting external noise. This is especially relevant in urban areas and along major transportation axes. Electric cars eliminate engine noise, and the relatively high-pitched noise electric motors do emit does not propagate as far. However, the faster vehicles are traveling, the more road and tire noise dominate, and the more wind passage noise contributes; those two are particularly important for internal acoustic comfort. Even for low speed urban driving conditions, BEV can have high tire noise contribution due to heavy battery and higher tire pressure.
Since without IC engine, the electric powertrain offers favorable conditions for a low operating external noise, still a careful NVH integration is necessary to achieve a NVH behavior compatible with an idea of quiet electric driving important for BEV customer.
Reference
1.
Gavric, L.: Electric vehicles and principal NVH issues: Proceedings of Automotive NVH Comfort – Le Mans, France 17–18 October 2018; SIA Conference (2018).
© Springer Fachmedien Wiesbaden GmbH, ein Teil von Springer Nature 2020
W. Siebenpfeiffer (Hrsg.)Automotive Acoustics Conference 2019Proceedingshttps://doi.org/10.1007/978-3-658-27669-0_2
NVH Design Criterion of Electric Powertrain Mounts
Qiang Kang¹ und Perry Gu¹
(1)
Geely Automobile Research Institute, Ningbo, China
Perry Gu
Email: gupengyun@geely.com
Abstract
Compared with the mechanical and combustion noise of low-frequency firing orders of an internal combustion engine, the electric drive assembly noise of electric vehicles is mainly the high-frequency whining noise generated by electromagnetic forces and transmission gear meshing. Although the radiated sound power is far less than that of an internal combustion engine, the high frequency noise of the electric motor and the transmission is much annoying. Noise below 2000–2500 Hz generated by an electric drive assembly in a vehicle passenger compartment is mainly contributed by structural transfer paths. Due to the high torque of the electric drive motor of electric vehicles, it is a challenge to achieve better mount isolation performance at the same time when the anti-torque performance of the electric drive assembly mounting system is realized. In this paper, by comparing the vibration characteristics of electric vehicles and traditional ICE vehicles, comparing different mount layout schemes, and analyzing the main factors affecting the vibration isolation rate of the electric drive assembly mounting system, the general design principles of the electric drive assembly mounting system are summarized to achieve balanced attribute performance.
1 Introduction
With the development of energy saving, environmental protection and intelligentization of vehicles, the automobile industry is moving toward electrification, automated driving and shared mobility. NVH of automobiles is also facing new challenges brought by electrification. Compared with the low-frequency mechanical and combustion noise of an internal combustion engine, the electric drive assembly noise is mainly the high-frequency whining noise generated by the electromagnetic force of the motor and gear meshing of the reducer [1]. Although the radiated sound power of the high frequency noise is much lower than that of the internal combustion engine noise, the high frequency noise of the motor and the reducer is subjectively quite annoying. In order to meet the user’s expectation of quietness in vehicle interiors, it is necessary to completely prevent the whining noise of the electric drive assembly from transmitting to the vehicle interior. On one hand, the high-frequency whining noise of the motor and reducer heard by the passengers in the interior is transmitted