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CAE Methods for Predicting Radiated Noise From Large Diameter Single-Piece Aluminum Propeller Shafts With Liner Treatments

General Motors-Rajith R. Jayaratne, Yu Liu, Mark Gehringer, Jeff Rayce, Wallace Hill
  • Technical Paper
  • 2019-01-1560
To be published on 2019-06-05 by SAE International in United States
In recent truck applications, single-piece large-diameter propshafts, in lieu of two-piece propshafts, have become more prevalent to reduce cost and mass. These large-diameter props, however, amplify driveline radiated noise. The challenge presented is to optimize prop shaft modal tuning to achieve acceptable radiated noise levels. This paper will cover the development of a two-step CAE method to predict modal characteristics and airborne noise sensitivities of large-diameter single piece aluminum propshafts fitted with different liner treatments. The first step is the use of a traditional CAE software to calculate prop surface response. The second step is a boundary element simulation to calculate prop surface radiating noise under the excitation obtained from the first step. Finally, test data, acceleration and acoustic, in both subsystem and vehicle levels are presented to assess the accuracy of the CAE method. The new CAE method can dramatically benefit driveline N&V integration, such as prop liner selection or prop modes tuning to reduce the driveline noise.
 

Truck front cabin mount tuning for cabin Noise boom elimination and overall interior noise reduction.

VE Commercial Vehicles Ltd-Sourabh Jadhav
VE Commercial Vehicles, Ltd.-Saahil Saxena
  • Technical Paper
  • 2019-01-1513
To be published on 2019-06-05 by SAE International in United States
In today's automobile industry refined NVH performance is a key feature and of high importance governing occupant comfort and overall quality impression of vehicle. This paper interior noise measurement is done on one of the light truck and few dominant low frequency noise booms were observed in operation range. Modal analysis was done for the cabin at virtual as well as experimental level and few modes were found close to these noise booms. Vibrations were measured across the various cabin mounts and it was found that the isolation of front mounts is not effective at lower boom frequencies. Taking this as an input, the mount hardness and profile optimized to shift the natural frequency and hence improve the isolation behavior at the lowest dominant boom frequency. This was followed by static and dynamic measurement of the mounts at test rig level and finally the interior noise measurement after fitment on truck. Boom elimination and overall interior noise reduction is achieved with this approach. This paper takes up a real-time noise scenario , its root cause…
 

Fast accurate non-destructive measurement of absorber impedance and absorption

3M-Jon Alexander
Bruel & Kjaer S&V Measurement A/S-Jason Kunio, Flemming Larsen
  • Technical Paper
  • 2019-01-1584
To be published on 2019-06-05 by SAE International in United States
Cabin acoustic comfort is a major contributor to the potential sales success of new aircraft, cars, trucks, and trains. Recent design challenges have included the increased use of composites, and the switch to electrically powered vehicles, each of which change the interior noise spectral content and level. The role of acoustic absorption in cabins is key to the optimisation of cabin acoustic comfort for modern vehicles, with acoustic impedance data needed in order to assess and optimise the impact of each component of a given lay-up. Measurements of absorbing interior trim are traditionally performed using either sample holder tests in a static impedance tube (impedance and absorption), or through tests in reverberation rooms (absorption only). Both of these procedures present challenges. In-tube absorption and impedance measurements are destructive, requiring highly accurate sample cutting and sealing. Reverberation room absorption measurements are subject to the effects of varying room diffusion, along with the impact of edge diffraction, sample geometry, and location. Finally, while non-destructive methods using hand-held probes also measure absorption, they are not able to measure…
 

Driveline NVH integration of A NA truck program

AAM (American Axle & Mfg Inc)-Christopher Folts, Alexander Sandstrom
American Axle & Manufacturing-Ying Peng, Zhaohui Sun, Gregory Kopp, Zhenghong Shi
  • Technical Paper
  • 2019-01-1559
To be published on 2019-06-05 by SAE International in United States
In current automotive industry, it is well known that the driveline subsystem and components are normally from different automotive suppliers for OEMs. In order to ensure proper system integration and successful development of driveline system NVH performances, collaboration efforts between OEMs and suppliers are very demanding and important. In this paper, a process is presented to achieve successfulness in developing and optimizing vehicle integration through effective teamwork between a driveline supplier and a major OEM. The development process includes multiple critical steps. They include target development and roll down, targets being specific and measurable, comprehension of interactions of driveline and vehicle dynamics, accurate definition of sensitivity, proper deployment of modal mapping strategy, which requires open data sharing; and system dynamics and optimization. More specially, the supplier can work with OEM to seek the most cost effective solutions, through tuning the driveline system dynamics to provide “quiet” frequency zone against vehicle sensitivity, to avoid normally needed costly suspension changes. A case study of a pickup vehicle driveline program integration is used in this paper to illustrate…
 

Heavy-Duty Aerodynamic Testing for CO2 Certification: A Methodology Comparison

Intl. Council on Clean Transportation-J. Felipe Rodriguez, Oscar Delgado
University of Technology Graz-Martin Rexeis, Martin Röck
  • Technical Paper
  • 2019-01-0649
To be published on 2019-04-02 by SAE International in United States
Aerodynamic drag testing is a key component of the CO2 certification schemes for heavy-duty vehicles around the world. This paper presents and compares the regulatory approaches for measuring the drag coefficient of heavy-duty vehicles in Europe, which uses a constant-speed test, and in the United States and Canada, which use a coastdown test. Two European trucks and one North American truck were tested using the constant-speed and coastdown methods. When corrected to zero yaw angle, a difference of up to 12% was observed in the measured drag coefficients from the US coastdown procedure and the EU constant-speed test. The differences in the measured drag coefficient can be attributed, among others, to the assumptions in the speed-dependence of the tire rolling resistance and axle spin losses, the data post-processing required by each methodology, unaccounted frictional losses in the transmission, the behavior of the automated manual transmission during the coastdown run, and the yaw angle correction.
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Methodology of Roller Bearing’s Preload Setting and Physical Verification of Axle in Tipper Application.

VE Commercial, Ltd.-Jeevan Ramesh Jathar
  • Technical Paper
  • 2019-01-1297
To be published on 2019-04-02 by SAE International in United States
The roller bearings and their performance is basic factor to uniqueness of transmission life, in automobile car, trucks as well as in tipper also. Transmission use helical gearing and taper roller bearings. The Continues running with heavy loads will deteriorate the performance of vehicle mainly due to bearing failures, that phenomenon happens because of improper alignment on shaft and wrong setting of preloading. The life of bearings L10 (Hrs) confirmed by setting of bearing preload (50 ~ 100 microns) through shim selection in accordance with the tolerance stack methodology. The bearings itself have radial as well as linear clearance depends on size and its application, while running of vehicle ( Dynamic Condition) bearings are taking all degrees of torque reactions and full-fill the transmission purpose, due to continuous high level of vibration through driveline and from power train , bearing sleeve loosening effects carry over there and deteriorate transmission performance, avoid such situation bearing’s clearances are optimized in accordance with consideration of application, load, temperature and fit called as preload. By this approach bearings are…
 

Evaluating a Heavy-Duty Truck Climate Control System Using Thermal Comfort-Focused Testing and Simulation Techniques

ThermoAnalytics Inc.-Mark Hepokoski, Steven Patterson, Allen Curran
Volvo Trucks North America-Steven Adelman, Miguel Javier
  • Technical Paper
  • 2019-01-0696
To be published on 2019-04-02 by SAE International in United States
A test protocol previously developed for automotive applications was adapted to evaluate the performance of a climate control system for a heavy-duty truck. Human subjects, as well as a test system composed of a high-resolution passive sensor manikin and a human thermal model, were employed to evaluate thermal comfort perception. Testing was performed in a climate-controlled wind tunnel equipped with a dynamometer. The truck’s HVAC system performance was evaluated in a −10 °C environment. Additionally, the test protocol was designed to explore a large range of thermal sensation and comfort states. Subjective responses, including thermal sensation and comfort, as well as thermo-physiological state information, quantified by skin temperatures measured across the body, were obtained from the human test participants and compared to that which was indicated by the test system.
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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…
 

A generalized component efficiency and input-data generation model for creating fleet-representative vehicle simulation cases in VECTO

Aristotle University of Thessaloniki-Nikiforos Zacharof
European Commission Joint Research-Alessandro Tansini, Theodoros Grigoratos, Georgios Fontaras
  • Technical Paper
  • 2019-01-1280
To be published on 2019-04-02 by SAE International in United States
The Vehicle Energy Consumption calculation Tool (VECTO) is used for the official calculation and reporting of CO2 emissions of HDVs in Europe. It uses certified input data in the form of energy or torque loss maps of driveline components and engine fuel consumption maps. Such data are proprietary and are not disclosed. Any further analysis of the fleet performance and CO2 emissions evolution using VECTO would require generic inputs or reconstructing realistic component input data. The current study attempts to address this issue by developing a process that would create VECTO input files based as much as possible on publicly available data. The core of the process is a series of models that calculate the vehicle component efficiency maps and produce the necessary VECTO input data. The process was applied to generate vehicle input files for rigid trucks and tractor-trailers of HDV Classes 4, 5, 9 and 10. Subsequently, evaluating the accuracy of the process, the simulation results were compared with reference VECTO results supplied by various vehicle manufacturers. The results showed that the difference…
 

A method for calculating Heavy-Duty Trucks energy and fuel consumption with the use of correlation formulas derived from VECTO simulations

Aristotle University of Thessaloniki-Nikiforos Zacharof
European Commission Joint Research-Alessandro Tansini, Georgios Fontaras, Biagio Ciuffo
  • Technical Paper
  • 2019-01-1278
To be published on 2019-04-02 by SAE International in United States
The Vehicle Energy Consumption calculation Tool (VECTO) is used in Europe for calculating standardised energy consumption and CO2 emissions from Heavy-Duty Trucks (HDTs) for certification purposes. The tool requires detailed vehicle technical specifications and a series of component efficiency maps, which are difficult to retrieve for those that are outside of the manufacturing industry. In the context of quantifying HDT CO2 emissions, the Joint Research Centre (JRC) of the European Commission received VECTO simulation data of the 2016 vehicle fleet from the vehicle manufacturers. In previous work, this simulation data has been normalised to compensate for differences and issues in the quality of the input data used to run the simulations. This work, which is a continuation of the previous exercise, focuses on the deeper meaning of the data received to understand the factors contributing to energy and fuel consumption. Fuel efficiency distributions and energy breakdown figures were derived from the data and are presented in this work. Correlation formulas were produced to calculate the energy loss contributions of individual components and resistances (air drag,…