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Govindswamy, Kiran
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Target Development for Transmission and Electric Motor NVH

FEV North America, Inc.-Todd Tousignant, Alex Ford, Kiran Govindswamy
Ford Motor Company-Justin Dech, Frederick Vanhaaften, Matthew Hettenhouse
Published 2019-06-05 by SAE International in United States
It is a common practice to conduct NVH fingerprinting and benchmarking assessments at the powertrain level, to understand source level noise and vibration. To assess the NVH influence of engine, e-motor, and transmission, sub-system testing is often conducted in addition to full powertrain testing. These powertrain or sub-system investigations provide valuable information regarding the status of “source” level excitations relative to targets and / or competitive powertrains. In the case of transmissions and e-machines, it is particularly important to understand source level tonal content and how this will be perceived at the vehicle level. However, variation in component design results in differences in order content, which complicates the process of objectively comparing multiple products.Multiple methods are presented here for characterizing tonal content of transmission and e-machines, based on assessments conducted in a component hemi-anechoic dynamometer test cell. Ultimately, sound quality is assessed by the customer at the vehicle level. Accordingly, the methods developed incorporate means of cascading results between component level and vehicle level. Furthermore, since the perception of tonal noise content is dependent upon…
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Assessment of Automotive Environmental Noise on Mobile Phone Hands-Free Call Quality

FEV North America, Inc.-Jeffrey Pruetz, Channing Watson, Todd Tousignant, Kiran Govindswamy
Published 2019-06-05 by SAE International in United States
Environmental noises such as wind, road, powertrain, and HVAC noise are important aspects to consider when implementing a hands-free terminal for mobile phone calling from within a car. Traditionally, these environmental noises have been exclusively considered for driver comfort; however, with the introduction of the hands-free terminals (HFT) and increasing consumer demand relative to mobile phone call quality, a broader implication of high background noise levels should be considered. HFT algorithm development and implementation can and does provide a high level of background noise suppression to mitigate these concerns, but this is often done at the expense of computational power and cumulative delay during a phone call. The more advantageous solution would be to address the problem from a source and path perspective with emphasis on reduction of noise in the frequency bands which most influence call quality performance. The assessments shown throughout this paper establish a sensitivity of HFT call quality to background noise levels based on industry-standard metrics, including those defined by International Telecommunication Union (ITU) standards. These assessments were established based on…
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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
Published 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 global demand for electric drive units (EDUs).The change from conventional vehicles to vehicles propelled by EDUs 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 as well as relatively high shares of road/wind noise. In order to ensure customer acceptance of electrically propelled vehicles, it is imperative that these NVH challenges are understood and solved.This paper discusses various aspects of the EDU NVH development process. This will include a discussion of the NVH target cascading methodologies for EDUs, followed by a description of…
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Reduction of Parasitic Losses in Front-End Accessory Drive Systems: Part 2

SAE International Journal of Engines

FEV Group GmbH-Stefan Trampert
FEV North America Inc.-Marek Tatur, Dean Tomazic, Kiran Govindswamy
  • Journal Article
  • 2018-01-0326
Published 2018-04-03 by SAE International in United States
Demanding CO2 and fuel economy regulations are continuing to pressure the automotive industry into considering innovative powertrain and vehicle-level solutions. Powertrain engineers continue to minimize engine internal friction and transmission parasitic losses with the aim of reducing overall vehicle fuel consumption.In Part 1 of the study (2017-01-0893) described aspects of the test stand design that provides flexibility for adaptation to various test scenarios. The results from measurements for a number of front-end accessory drive (FEAD) components were shown in the context of scatterbands derived from multiple component tests. Key results from direct drive and belt-driven component tests were compared to illustrate the influence of the belt layout on mechanical efficiency of the FEAD system.The second part of the series will focus exclusively on the operation of the alternator. Two main elements of the study are discussed. The first part explores tests performed to evaluate the main design aspects of the component. Different belt designs, routing, and tension levels were tested and compared. A resulting matrix allows to determine an optimized belt design and layout for…
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Assessment of Lightweight Automotive Glass Solutions on Interior Noise Levels & Sound Quality

Corning Inc.-Vikram Bhatia, Shivani Polasani, W Keith Fisher
FEV North America, Inc.-Todd Tousignant, Kiran Govindswamy
Published 2017-06-05 by SAE International in United States
The automotive industry continues to develop technologies for reducing vehicle fuel consumption. Specifically, vehicle lightweighting is expected to be a key enabler for achieving fleet CO2 reduction targets for 2025 and beyond. Hybrid glass laminates that incorporate fusion draw and ion exchange innovations are thinner and thereby, offer more than 30% weight reduction compared to conventional automotive laminates. These lightweight hybrid laminates provide additional benefits, including improved toughness and superior optics. However, glazing weight reduction leads to an increase in transmission of sound through the laminates for certain frequencies. This paper documents a study that uses a systematic test-based approach to understand the sensitivity of interior vehicle noise behavior to changes in acoustic attenuation driven by installation of lightweight glass. Specifically, this study evaluates the influence of a lightweight windshield on wind, road, and powertrain contributions to vehicle interior noise.To facilitate this assessment, operating tests were conducted utilizing variable operating conditions and road surfaces such that varying balances of powertrain, wind, and road-induced interior vehicle noise could be evaluated. A time-domain noise transfer path analysis…
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Impact of the Future Fuel Economy Targets on Powertrain, Driveline and Vehicle NVH Development

SAE International Journal of Vehicle Dynamics, Stability, and NVH

FEV North America, Inc.-Thomas Wellmann, Kiran Govindswamy, Dean Tomazic
  • Journal Article
  • 2017-01-1777
Published 2017-06-05 by SAE International in United States
The automotive industry continues to develop new technologies aimed at reducing overall vehicle level fuel consumption. Powertrain and driveline related technologies will play a key role in helping OEM’s meet fleet CO2 reduction targets for 2025 and beyond. Specifically, use of technologies such as downsized engines, idle start-stop systems, aggressive torque converter lock-up schedules, wide-ratio spread transmissions, and electrified propulsion systems are vital towards meeting aggressive fuel economy targets. Judicious combinations of such powertrain and driveline technology packages in conjunction with measures such as the use of low rolling resistance tires and vehicle lightweighting will be required to meet future OEM fleet CO2 targets. Many of the technologies needed for meeting the fuel economy and CO2 targets come with unique NVH challenges. In order to ensure customer acceptance of new vehicles, it is imperative that these NVH challenges be understood and solved.This paper will begin with an introduction of the legislative framework with respect to fuel economy and CO2 targets for light duty vehicles. Key megatrends of engine, transmission, driveline, and electrified propulsion systems will…
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Optimization of Electric Vehicle Exterior Noise for Pedestrian Safety and Sound Quality

FEV Europe GmbH-Georg Eisele, Christoph Steffens
FEV North America, Inc-Kiran Govindswamy
Published 2017-06-05 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. Electric and hybrid electric vehicles do not typically utilize IC engines for low-speed operation. Under these low-speed operating conditions, the vehicles are much quieter than conventional IC engine-powered vehicles, making their approach difficult to detect by pedestrians. To mitigate this safety concern, many manufacturers have synthesized noise (using exterior speakers) to increase detection distance. Further, the US National Highway Traffic Safety Administration (NHTSA) has provided recommendations pursuant to the Pedestrian Safety Enhancement Act (PSEA) of 2010 for such exterior noise signatures to ensure detectability. This has created potential challenges for automakers to meet the anticipated regulatory requirements while maintaining a high level of sound quality for both exterior and interior noise.In development of exterior noise signals, the goal is to achieve the required levels and transient pitch requirements, while ensuring…
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Reduction of Parasitic Losses in Front-End-Accessory-Drive Systems - Part 1

FEV North America Inc.-Marek Tatur, Kiran Govindswamy, Dean Tomazic
Published 2017-03-28 by SAE International in United States
Demanding CO2 and fuel economy regulations are continuing to pressure the automotive industry into considering innovative powertrain and vehicle-level solutions. Powertrain engineers continue to minimize engine internal friction and transmission parasitic losses with the aim of reducing overall vehicle fuel consumption. Strip friction methods are used to determine and isolate components in engines and transmissions with the highest contribution to friction losses. However, there is relatively little focus on friction optimization of Front-End-Accessory-Drive (FEAD) components such as alternators and Air Conditioning (AC) compressors. This paper expands on the work performed by other researchers’ specifically targeting in-depth understanding of system design and operating strategy. Prime focus of the first part of the study is to outline the development of a flexible test stand that allows for highly accurate torque measurements on such components under precisely controlled environmental boundary conditions and device loads. Initial testing results from multiple test units are also presented.This paper will detail aspects of the test stand design that provide flexibility for adaptation to various test scenarios. The results from measurements for a…
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Vehicle NVH Evaluations and NVH Target Cascading Considerations for Hybrid Electric Vehicles

FEV North America, Inc.-Todd Tousignant, Kiran Govindswamy
Ford Motor Company-Mark Stickler, Ming-Ran Lee
Published 2015-06-15 by SAE International in United States
The increasing trend toward electric and hybrid-electric vehicles (HEVs) has created unique challenges for NVH development and refinement. Traditionally, characterization of in-vehicle powertrain noise and vibration has been assessed through standard operating conditions such as fixed gear engine speed sweeps at varied loads. Given the multiple modes of operation which typically exist for HEVs, characterization and source-path analysis of these vehicles can be more complicated than conventional vehicles.In-vehicle NVH assessment of an HEV powertrain requires testing under multiple operating conditions for identification and characterization of the various issues which may be experienced by the driver. Generally, it is necessary to assess issues related to IC engine operation and electric motor operation (running simultaneously with and independent of the IC engine), under both motoring and regeneration conditions. Additionally, mode transitions, including IC engine start/stop must be assessed.An analysis is presented here, which explores the differences in NVH performance of multiple HEVs currently available in the US-market. Measurements were conducted on these vehicles to assess noise and vibration at the powertrain-level and vehicle interior. Two of the…
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Influence of Automatic Engine Stop/Start Systems on Vehicle NVH and Launch Performance

SAE International Journal of Engines

FCA US LLC-Jeff Orzechowski, Sudharsan Srinivasan
FEV North America, Inc.-Thomas Wellmann, Kiran Govindswamy
  • Journal Article
  • 2015-01-2183
Published 2015-06-15 by SAE International in United States
Integration of automatic engine Stop/Start systems in “conventional” drivetrains with 12V starters is a relatively cost-effective measure to reduce fuel consumption. Therefore, automatic engine Stop/Start systems are becoming more prevalent and increasing market share of such systems is predicted. A quick, reliable and consistent engine start behavior is essential for customer acceptance of these systems. The launch of the vehicle should not be compromised by the Stop/Start system, which implies that the engine start time and transmission readiness for transmitting torque should occur within the time the driver releases the brake pedal and de-presses the accelerator pedal. Comfort and NVH aspects will continue to play an important role for customer acceptance of these systems. Hence, the engine stop and re-start behavior should be imperceptible to the driver from both a tactile and acoustic standpoint.This paper describes the details of various powertrain calibration factors for the engine start process. The key phases of an engine start event are described in detail, and their influence on the vehicle vibration investigated. The engine stop behavior is analyzed with…
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