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Investigation and Improvement of a Bouncing Torsional Vibration in Automotive Dual Mass Flywheel by Combining Testing and 1D CAE Modeling Approach

Doshisha University-Nobutaka Tsujiuchi, Akihito Ito
EXEDY Corp.-Yoshihiro Yamakaji, Daisuke Yoshimoto
Published 2019-06-05 by SAE International in United States
Dual mass flywheel (DMF) is a well-known isolation system for vehicle drivetrain. DMF has two typical elastic energy storage systems: long travel arc springs and in-series spring units (including two or more springs) and sliding shoes connected in series. DMF has such complex nonlinear characteristics as torque-dependent torsional stiffness and rotational speed-dependent hysteresis friction due to its dependency of centrifugal force that is applied to components and radial force of springs. Because of this complexity, sub-harmonic vibration (SHV) may occur under certain circumstances, such as under light-load and high-rotational conditions. In general, since SHV’s frequency is 1/2 or 1/3 of the engine’s combustion frequency and may cause human discomfort, DMF must be designed robust against such nonlinear vibration. In this paper to reduce the SHV occurrence and to show a more robust design indicator, the SHV causing the mechanism is researched by testing and 1D CAE modeling. In detail, DMF interior behavior in high-speed rotation is clarified with high-speed cinematography on a test bench, and high-resolution relative torsional angle of DMF is obtained by evaluating…
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Battery Electrolyte Doubles Driving Range for Electric Vehicles

  • Magazine Article
  • TBMG-34610
Published 2019-06-01 by Tech Briefs Media Group in United States

Conventional electrolytes used in lithium-ion batteries that power household electronics like computers and cellphones are not suitable for lithium-metal batteries. Lithium-metal batteries that replace a graphite electrode with a lithium electrode are the holy grail of energy storage systems because lithium has a greater storage capacity and, therefore, a lithium-metal battery has double or triple the storage capacity. That extra power enables electric vehicles to drive more than two times longer between charges.

 

Wireless Power Transfer for Light-Duty Plug-in/Electric Vehicles and Alignment Methodology

Hybrid - EV Committee
  • Ground Vehicle Standard
  • J2954_201904
  • Current
Published 2019-04-23 by SAE International in United States
The Recommended Practice SAE J2954 establishes an industry-wide specification that defines acceptable criteria for interoperability, electromagnetic compatibility, EMF, minimum performance, safety, and testing for wireless charging of light-duty electric and plug-in electric vehicles. The specification defines various charging levels that are based on the levels defined for SAE J1772 conductive AC charge levels 1, 2, and 3, with some variations. A standard for wireless power transfer (WPT) based on these charge levels enables selection of a charging rate based on vehicle requirements, thus allowing for better vehicle packaging and ease of customer use. The specification supports home (private) charging and public wireless charging. In the near term, vehicles that are able to be charged wirelessly under Recommended Practice SAE J2954 should also be able to be charged by SAE J1772 plug-in chargers. This Recommended Practice is planned to be standardized after the 2018 timeframe after receiving vehicle data. The contents, including frequency, parameters, specifications, procedures, and other contents of this Recommended Practice, are to be re-evaluated at that time to allow for additional developments and…
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Comparison of Particulate Emissions of a Range Extended Electric Vehicle under Different Energy Management Strategies

Tongji University-Yaxin Wang, Diming Lou, Ning Xu, Piqiang Tan, Zhiyuan Hu
Published 2019-04-02 by SAE International in United States
Range extended electric vehicles achieve significant reductions in fuel consumption by employing as an energy source a small displacement combustion engine that is optimized for high efficiency at one, or a few, operating points. The present paper examines the impact of various energy management strategies on the particulate emissions from the auxiliary power unit (APU) of a range extended electric bus, including optimized auxiliary power unit (APU) on/off strategy, single-point strategy, two-point strategy, power-following strategy and equivalent fuel consumption minimization strategy (ECMS). In addition, this paper also compares the particulate emissions of single energy storage system and composite energy storage system on single-point energy management strategy. The main conclusions in this paper are as follows: After optimizing the APU on/off strategy, the APU starts and stops frequently to make the cylinder temperature relatively low, which results in the reductions of both the particle mass (PM) and the particle number (PN). The application of two-point strategy and power-following strategy maximizes the output power of high load, and then the particulate emission presents significant increasing. With the…
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Design of a Grid-Friendly DC Fast Charge Station with Second Life Batteries

Ohio State University-Matilde D'Arpino, Massimo Cancian
Published 2019-04-02 by SAE International in United States
DC-fast charge (DCFC) may be amenable for widespread EV adoption. However, there are potential challenges associated with implementation and operation of the DCFC infrastructures. The integration of energy storage systems can limit the scale of grid installation required for DCFC and enable more efficient grid energy usage. In addition, second-life batteries (SLBs) can find application in DCFC, significantly reducing installation cost when compared to solutions based on new battery packs. However, both system architecture and control strategy require optimization to ensure an optimal use of SLBs, including degradation and thermal aspects. This study proposes an application of automotive SLBs for DCFC stations where high power grid connection is not available or feasible. Several SLBs are connected to the grid by means of low power chargers (e.g. L2 charging station), and a DC/DC converter controls the power to the EV power dispenser. The architecture of the DC bus, the size and state of health of the battery system determine efficiency, cost, and reliability of the station. A technical and economic comparison is proposed, evaluating solutions with…
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Energy Management Strategy and Size Optimization of a LFP/LTO Hybrid Battery System for Electric Vehicle

Nanjing University of Science and Techno-Yang Ding
Southeast University-Guangmin Li, Weichao Zhuang, Guodong Yin, Yanjun Ren
Published 2019-04-02 by SAE International in United States
This paper proposes a semi-active hybrid battery system (HBS), composed by lithium iron phosphate battery (LFP) and lithium titanate battery (LTO) for electric vehicle (EV) to reduce the life cycle cost of energy storage system. Firstly, the topology of this HBS is introduced. The high energy-density battery, LFP is adopted as the primary energy source, while the high power-density one, LTO is connected in parallel with a bidirectional DC-DC converter and used as secondary energy source to extend the lifetime of HBS by reducing the current stress of LFP. The dynamic model of this HBS is built, in which, the LFP and LTO are both modeled as second-order RC model. In addition, dynamic semi-empirical degradation model of the LFP battery is chosen to estimate the lifetime of HBS. Secondly, a fuzzy logic controller with 3 inputs and 1 output is proposed to decide the power split between the primary and secondary power sources. LFP and LTO both could provide power to drive the vehicle, while the electricity generated by regenerative braking is only stored in…
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Achieving Carbon Footprint Reduction with Flywheel Technology

  • Magazine Article
  • TBMG-34146
Published 2019-04-01 by Tech Briefs Media Group in United States

Recent technical advances have enabled flywheel energy storage systems (FESS) to become more compact and able to support higher-power applications. Due to their proven reliability, low cost of ownership, and favorable green environmental aspects, engineers and managers of data centers, hospitals, industrial systems, electric rail, and microgrid applications are reaping the benefits of clean energy storage that flywheels offer.

 

Technical Information Report on Automotive Battery Recycling

Battery Standards Recycling Committee
  • Ground Vehicle Standard
  • J2974_201902
  • Current
Published 2019-02-11 by SAE International in United States
This document will focus on the language used to describe batteries at the end of battery or vehicle life as batteries are transitioned to the recycler, dismantler, or other third party. This document also provides a compilation of current recycling technologies and flow sheets, and their application to different battery chemistries at the end of battery life. At the time of document authorship, the technical information cited is most applicable to Li-ion battery type rechargeable energy storage systems (RESS), but the language used is not to be limited by chemistry of the battery systems and is generally applicable to other RESS.
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An Introduction to PCM Heat Sinks

Aerospace & Defense Technology: February 2019

  • Magazine Article
  • 19AERP02_02
Published 2019-02-01 by SAE International in United States

With the exception of thermal storage heat sinks, the term heat sink is a misnomer. Standard heat sinks for electronics cooling are actually heat exchangers, taking the heat from the electronics, and transferring it to a fluid, either air or coolant. Phase Change Material (PCM) heat sinks are the only heat sinks that actually act as a (temporary) sink for heat. They are emerging in the thermal management realm to solve thermal problems in systems where active solutions cannot be used. When there is no place to dissipate the heat generated by electric components, a PCM heat sink is capable of absorbing the generated waste heat [1].

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A Heuristic Supervisory Controller for a 48V Hybrid Electric Vehicle Considering Fuel Economy and Battery Aging

Clemson University-Farzam Malmir, Bin Xu, Zoran Filipi
Published 2019-01-15 by SAE International in United States
Most studies on supervisory controllers of hybrid electric vehicles consider only fuel economy in the objective function. Taking into consideration the importance of the energy storage system health and its impact on the vehicle’s functionality, cost, and warranty, recent studies have included battery degradation as the second objective function by proposing different energy management strategies and battery life estimation methods. In this paper, a rule-based supervisory controller is proposed that splits the torque demand based not only on fuel consumption, but also on the battery capacity fade using the concept of severity factor. For this aim, the severity factor is calculated at each time step of a driving cycle using a look-up table with three different inputs including c-rate, working temperature, and state of charge of the battery. The capacity loss of the battery is then calculated using a semi-empirical capacity fade model. Eventually, the fuel economy, and capacity loss as two of the most important objectives are compared with and without implementing the proposed controller. In the comparative study, four customized driving cycles are…
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