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Brake Effectiveness Marking for Brake Blocks - Truck and Bus

Truck and Bus Foundation Brake Committee
  • Ground Vehicle Standard
  • J1801_201906
  • Current
Published 2019-06-06 by SAE International in United States

This SAE Recommended Practice provides the method to assign numerical values of brake effectiveness, using data from single station inertia dynamometer effectiveness tests, and to identify a uniform procedure to mark these values on the edge of brake blocks in excess of 12.7 mm (0.51 in) in thickness.

 
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Vibro-Acoustic Analysis for Modeling Propeller Shaft Liner Material

General Motors-Rajith R. Jayaratne, Yu Liu, Mark Gehringer, Jeff Rayce, Wallace Hill
Published 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. Historically, CAE methods and capabilities have not been able to accurately predict propshaft airborne noise making it impossible to cascade subsystem noise requirements needed to achieve desired vehicle level performance. As a result, late and costly changes can be needed to make a given vehicle commercially acceptable for N&V performance prior to launch.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 radiated noise under the excitation obtained from the first step. Finally, acceleration and acoustic test data are presented to assess…
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Fast Accurate Non-Destructive Measurement of Absorber Impedance and Absorption

3M Company-Jon Alexander
Bruel & Kjaer Sound and Vibration A/S-Jason Kunio, Flemming Larsen
Published 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 impedance…
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Driveline NVH Integration of An NA Truck Program

American Axle & Manufacturing-Ying Peng, Zhenghong Shi, Christopher Folts, Gregory Kopp, Zhaohui Sun, Alexander Sandstrom
Published 2019-06-05 by SAE International in United States
In the current automotive industry, it is common 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. Two case studies of a pick-up vehicle driveline program integration are used in this paper to illustrate the effectiveness…
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Toyota's proven fuel-cell stack reduces cost, complexity in H2 semi-truck

SAE Truck & Off-Highway Engineering: June 2019

Sebastian Blanco
  • Magazine Article
  • 19TOFHP06_14
Published 2019-06-01 by SAE International in United States

Hydrogen proponents likely know that Mirai means “future” in Japanese, but Toyota is only just beginning to explore how important the fuel cell stack in its H2-powered passenger car will be to the future of the company.

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Getting driverless trucks onto roadways

SAE Truck & Off-Highway Engineering: June 2019

based on exclusive interview with TuSimple's Chuck Price-Terry Costlow
  • Magazine Article
  • 19TOFHP06_03
Published 2019-06-01 by SAE International in United States

Autonomous developers at TuSimple address many technical issues, but they also must consider regulations and operating modes.

The developers who are creating autonomous systems have plenty of complex technical questions that must be analyzed and solved, but their challenges don't stop there. Design teams also have to plan for the use cases of driverless vehicles, even going so far as to plan for what might happen if the vehicle has to sacrifice itself to avoid a serious accident.

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HYDROGEN BOOM!

SAE Truck & Off-Highway Engineering: June 2019

Ryan Gehm
  • Magazine Article
  • 19TOFHP06_05
Published 2019-06-01 by SAE International in United States

Nikola reveals Two and Tre fuel-cell trucks and its H2 fueling roadmap, as well as battery-electric military and powersports vehicles.

On-highway Class 6-8 trucks are Nikola's main business and engineering focus, but the Arizona-based startup is expanding its product range to include powersports and military sectors to demonstrate its technology's adaptability. In addition to the Nikola Two and Tre hydrogen fuel-cell trucks for North America and Europe, respectively, the manufacturer revealed a battery-electric all-terrain vehicle, an autonomous-capable military vehicle and a personal-watercraft concept to about 2,000 attendees of the Nikola World opening event in Scottsdale, Ariz., near the company's Phoenix headquarters.

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EDITORIAL: Diesel's doing just fine, thank you

SAE Truck & Off-Highway Engineering: June 2019

Editor-in-Chief-Ryan Gehm
  • Magazine Article
  • 19TOFHP06_08
Published 2019-06-01 by SAE International in United States

Alternative propulsion features prominently in this issue, starting from the cover shot of Nikola's sleek fuel-cell electric Class 8 tractor, the Two, and continuing into the annual Executive Viewpoints series of articles, in which experts discuss the challenges and opportunities in a range of technology areas, including biomethane and hybrid power systems.

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Security, bandwidth drive over-the-air development

SAE Truck & Off-Highway Engineering: June 2019

Terry Costlow
  • Magazine Article
  • 19TOFHP06_10
Published 2019-06-01 by SAE International in United States

Over-the-air (OTA) updating has evolved rapidly from a limited function to a wide-ranging technology for keeping vehicle software up to date. As OTA moves deeper into the mainstream, commercial-vehicle suppliers are focusing on security and techniques that efficiently allow downloading of a growing number of files.

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Cleaner Trucks Initiative starts NOx-reduction journey

SAE Truck & Off-Highway Engineering: June 2019

Bruce Morey
  • Magazine Article
  • 19TOFHP06_12
Published 2019-06-01 by SAE International in United States

The U.S. Environmental Protection Agency (EPA) is in the beginning stages of establishing new NOx regulations for heavy-duty on-highway trucks. The agency is spurred by advances in technology and a desire to streamline the certification process.

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