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Structural Vibration and Acoustic Analysis of a 3-Phase AC Induction Motor

Peyman Poozesh
Kettering Univ-Allan Taylor, Javad Baqersad
  • Technical Paper
  • 2019-01-1458
To be published on 2019-06-05 by SAE International in United States
This paper is aimed at studying the NVH and acoustic performance of a 3-phase AC induction motor in order to find a way to reduce the magnetic component of noise from an electric motor in an electric vehicle (EV). The method suggested here is to reduce the magnetic component of sound from the motor by making modifications to the end bracket of the motor housing. EVs are being considered the future of mobility mainly owing to the fact that they are environment-friendly. With a lot of companies already investing heavily in this technology, electric drives are set to become extremely popular in the years to come. The heart of an EV is its motor. Modern electric vehicles are quiet and with the lack of an IC engine to mask most sounds from other components, the sound from the electric motor and other auxiliary parts become more prominent. This paper lays down a process to analyze the sound radiated from the electric motor in three broad steps. First, to model the motor in an electromagnetic platform,…

Target Setting Process for Hybrid Electric Drives Using TPA, Jury Studies, and Torque Management

FCA US LLC-Vinod Singh, Anil Charan
  • Technical Paper
  • 2019-01-1453
To be published on 2019-06-05 by SAE International in United States
The idea of improved efficiency without compromising the “fun to drive” aspect has renewed the auto industry’s interest toward electrification and hybridization. Electric drives benefit from having multiple gear ratios which can use advantageous operating set points thus increasing range. Hybrid vehicles benefit significantly from frequent decelerations and stopping as is experienced in city driving conditions. To recuperate as much energy as possible, deceleration is done at high torque. This presents an interesting but serious sound quality issue in the form of highly tonal whine harmonics of rapidly changing gears that do not track with vehicle speed thus being objectionable to the vehicle occupants. This paper presents an NVH target setting process for a hybrid electric transmission being integrated into two existing vehicles, one belonging to the premium segment and another aimed at enthusiasts with off-road applications. The demand for power has shifted from mechanical domain into electrical domain, and as such, the solution to electric drive NVH issues also lies partly, in the way these drive systems are calibrated. A time-domain Transfer Path Analysis…

Test and Analysis of Electromagnetic Noise of an Electric Motor in a Pure Electric Car

Geely Automobile Research Institute-Perry Gu, Chao Gong
Geely Automoile Research Institute-Qiang kang
  • Technical Paper
  • 2019-01-1492
To be published on 2019-06-05 by SAE International in United States
Compared with the low-frequency ignition order of mechanical and combustion noise of the internal combustion engine, the electric drive assembly noise of electric vehicles is mainly the high-frequency whining order noise generated by the electromagnetic force and gear meshing, as well as the high-frequency umbrella noise generated by DC/AC pulse width modulation. Although the radiated sound power is far less than that of an internal combustion engine, the high frequency noise of the motor and the reducer is also annoying. In this paper, the main characteristics of the vibration and noise of an electric motor are obtained by testing it on the vehicle and on the test rig. The main frequency orders are multiplies of motor poles, of which the most significant is the 48th order. The deformation of the motor at the resonance frequency of the 48th order is the breathing mode. Through analysis of electromagnetic force wave, the sources of main orders of motor noise are explained. The most significant order 48th comes from the interaction between rotor magnetic field and stator slots.…

Effectiveness of Power-law Profile Indentations on Structure-Borne Noise

General Motors-Jeffrey Curtis
General Motors Technical Center India-Pranoy Sureshbabu Nair, Nilankan Karmakar, Seshagiri Rao Maddipati
  • Technical Paper
  • 2019-01-1496
To be published on 2019-06-05 by SAE International in United States
With the focus shifting towards to the electric drives, owing to the stringent requirements for noise and vibrations, different measures are being taken to reduce the energy loss from the system via noise or heat dissipation but the conventional N&V approach of increasing the stiffness of the flexible component and reducing the mass may not always help in avoiding the resonance condition with the unwanted excitations owing to a wide range of operating range for motors and absence of engine noise makes it worse. Apart from any structural modifications, implementation of sound barriers like acoustic covers for sound absorption is also generally adopted for noise treatment. Locally modifying the structure thickness between two spatial locations helps in decreasing the reflection coefficient at the terminating edges thus reducing reflection of flexural waves. Power law profiles where the thickness gradually decreases along the space with an order greater than 1 are found to be more effective in reducing wave reflections. Recent research on locally modifying the wave velocity by implementing power law profiles within the structure have…

NVH Aspects of Electric Drive Unit Development and Vehicle Integration

FEV Europe GmbH-Christoph Steffens, Peter Janssen
FEV North America Inc.-Thomas Wellmann, Todd Tousignant, Kiran Govindswamy, Dean Tomazic
  • Technical Paper
  • 2019-01-1454
To be published on 2019-06-05 by SAE International in United States
The automotive industry continues to develop new powertrain and vehicle technologies aimed at reducing overall vehicle-level fuel consumption. Specifically, the use of electrified propulsion systems is expected to play an increasingly important role in helping OEM’s meet fleet CO2 reduction targets for 2025 and beyond. This will also include a strong growth in the demand for electric drive units (EDU). The change from conventional vehicles to vehicles propelled by EDU leads to a reduction in overall vehicle exterior and interior noise levels, especially during low-speed vehicle operation. Despite the overall noise levels being low, the NVH behavior of such vehicles can be objectionable due to the presence of tonal noise coming from electric machines and geartrain components. In order to ensure customer acceptance of electrically propelled vehicles, it is imperative that these NVH challenges are understood and solved

Experimental PEM-Fuel Cell Range Extender System Operation and Parameter Influence Analysis

Vienna University of Technology-Johannes Höflinger, Peter Hofmann, Bernhard Geringer
  • Technical Paper
  • 2019-01-0378
To be published on 2019-04-02 by SAE International in United States
Fuel cells as alternative propulsion systems in vehicles can achieve higher driving ranges and shorter refueling times compared to pure battery-electric vehicles, while maintaining the local zero-emission status. However, to take advantage of pure battery electric driving, an externally rechargeable battery can be combined with a fuel cell range extender. As part of a research project, an efficient air supply system for a fuel cell range extender was developed. To this end, a 25 kW PEM fuel cell system test bench was set up. The different parameter influences of the test bench, in particular of the air supply system, were analyzed and evaluated in terms of stack/system efficiency and functionality. The control software of the test bench was specifically developed for the flexible operating parameter variation. All adjustable variables of the system (air ratio, stack temperature, pressure, etc.) were varied and evaluated at steady-state operating points. Likewise, the system was analyzed during dynamic operation and fault cases in adverse operating conditions (water condensation, oxygen deficiency) were identified. The system's warm-up process was also evaluated in…
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Design of an Electric Drive Transmission for a Formula Student Race Car

Gavin White, Geoffrey Cunningham, Darryl Doyle
  • Technical Paper
  • 2019-01-1295
To be published on 2019-04-02 by SAE International in United States
This paper presents a methodology used to configure an electric drive system for a Formula Student car and the detailed design of a transmission for in-hub motor placement. Various options for the size, number and placement of electric motors were considered and a systematic process was undertaken to determine the optimum configuration and type of motor required. The final configuration selected had four 38 kW in-hub motors connected through a 14.8:1 reduction transmission to 10” wheels. Preliminary design of the transmission indicated that the overall gear ratio would be best achieved with a two-stage reduction, and in this work an offset primary spur stage coupled to a planetary second stage was chosen. Detailed design and validation of the transmission was conducted in Ricardo SABR and GEAR, using a duty cycle derived from an existing internal combustion Formula Student car. The analysis was conducted in line with ISO 6336 and permitted the examination of the stresses in gear teeth and the prediction of gear and bearing life. A detailed design was proposed with due regard to…
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Robot-Based Fast Charging of Electric Vehicles

Graz University of Technology-Bernhard Walzel, Mario Hirz, Helmut Brunner
representing BMW Group-Nico Kreutzer
  • Technical Paper
  • 2019-01-0869
To be published on 2019-04-02 by SAE International in United States
Automated, conductive charging systems enable both the transmission of high charging power for long electric driving distances as well as comfortable and safe charging processes. Particularly in connection with autonomously driving and parking vehicles, new fields of application and opportunities are emerging. This paper deals with the definition of requirements for automated conductive charging stations and highlights the development and conception of a robot-based prototype for automated charging of electric and plug-in hybrid vehicles. In cooperation with the project partners BMW AG, Magna Steyr Engineering, KEBA AG and the Institute of Automotive Engineering of Graz University of Technology, the development and implementation of the prototype took place in the course of a governmental funded the research project titled “KoMoT”. In the presented approach, the entire docking and undocking process of the charging cable is performed completely autonomously by a robotic arm. An essential aim of the research activities was to design the sensor technology and the robot system control in such a way, that even when using different vehicle types and vehicle positions no adaptations…

The Coordinated Control of Plug-In Hybrid Electric Vehicle during Engine Starting in Driving Process

ASCL Jilin University-Yulong Lei, Pengxiang Song, Yao Fu, Fei Guo
  • Technical Paper
  • 2019-01-0361
To be published on 2019-04-02 by SAE International in United States
The number of internal combustion engine vehicles are growing rapidly, and the resulting energy crisis and air pollution are becoming more and more serious. Pure electric vehicles are subject to imperfect battery technology and infrastructure, the driving mileage and charging time will cause troubles to consumers. Plug-in hybrid electric vehicles (PHEV) incorporating the advantages of traditional internal combustion engine vehicles and pure electric vehicles, can achieve the purpose of energy conservation and emission reduction and has been the research hotspot in the field of new energy vehicles. PHEV has multiple operating modes, when operating mode switching, inadequate control could result in poor ride comfort. Therefore, research on the smoothness control of the switching mode of PHEV is crucial.In this paper, the plug-in hybrid electric vehicle with a Dual-Clutch Automatic Transmission (DCT) is taken as the research object, and the dynamic model of the process which the electric drive mode switching to the engine drive mode is established and analyzed. Aiming at the problem of the vehicle impact caused by the fluctuation of the driving torque…
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Modeling of Engine After Treatment System Cooling for Hybrid Vehicles

Linköping University-Olov Holmer, Lars Eriksson
Volvo Group Trucks Technology-Fredrik Blomgren
  • Technical Paper
  • 2019-01-0989
To be published on 2019-04-02 by SAE International in United States
The medium and heavy duty transport industry is currently showing a growing interest in hybrid powertrains. Currently, this technology is mainly used in buses but distribution trucks, both heavy and medium duty, are expected to become growing market segments. Hybrid trucks are potentially superior to conventional internal combustion engine (ICE) propelled trucks in a wide range of environmental areas like noise, CO2 and NOx emissions. However, since the hybrid vehicle is still partially powered by an ICE, an engine after treatment system (EATS) is necessary. Traditionally, the EATS is heated by the waste heat entering the tail pipe after the turbo. This is the most fuel efficient and practical way of bringing the EATS up to and maintaining operating temperatures of about 200 - 400 ̊C, where it's most efficient. However, in hybrid vehicles the ICE can be shut off to a larger extent than in conventional vehicles, and when the engine is off the EATS cools down. Eventually the EATS will drop below the desired temperature range making the EATS ineffective when the ICE…