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Closed Loop Control Algorithm of Fuel Cell Output Power for a City Bus

SAE International Journal of Alternative Powertrains

Sunrise Power Co,. Ltd.-Quanquan Gan
Tsinghua Univ-Minggao Ouyang, Jianqiu Li, Haiyan Huang, Fuyuan Yang
  • Journal Article
  • 2013-01-0479
Published 2013-04-08 by SAE International in United States
This paper studies a control algorithm for fuel cell/battery city buses. The output power of the fuel cell is controlled by a D.C. converter, and the output ports of the converter and the battery are connected in parallel to supply power for the electric motor. One way to prolong service life is to have the fuel cell system to deliver a steady-state power. However, because of fluctuations in the bus voltage and uncertainness in the D.C. converter, the output power of the fuel cell system changes drastically. A closed-loop control algorithm is necessary to eliminate the errors between the output and target power of the fuel cell system. The algorithm is composed of two parts, the feed forward one and the feedback one. Influences of the bus voltage and D.C. efficiency are compensated automatically in the feedback algorithm by using a PI algorithm. The stability and robustness of the algorithm is analyzed. Formulas for choosing suitable parameters are given considering both the transient process and the system stability. Experimental results show that, the stable relative…
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Regenerative Braking Control Enhancement for the Power Split Hybrid Architecture with the Utilization of Hardware-in-the-loop Simulations

SAE International Journal of Alternative Powertrains

Ford Motor Co-Kerem Bayar, Ryan McGee, Hai Yu, Dale Crombez
  • Journal Article
  • 2013-01-1466
Published 2013-04-08 by SAE International in United States
This study presents the utilization of the hardware-in-the-loop (HIL) approach for regenerative braking (regen) control enhancement efforts for the power split hybrid vehicle architecture. The HIL stand used in this study includes a production brake control module along with the hydraulic brake system, constituted of an accelerator/brake pedal assembly, electric vacuum booster and pump, brake hydraulic circuit and four brake calipers.This work presents the validation of this HIL simulator with real vehicle data, during mild and heavy braking. Then by using the HIL approach, regen control is enhanced, specifically for two cases. The first case is the jerk in deceleration caused by the brake booster delay, during transitions from regen to friction braking. As an example, the case where the regen is ramped out at a low speed threshold, and the hydraulic braking ramped in, can be considered. During this transition, due to the communication delay and the delay associated with booster dynamics, the regen ramp out and hydraulic braking ramp in are not perfectly synchronized, which can cause a jerk in deceleration.The second case…
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Development of a Smart Main Relay Assembly using IGBTs for xEV Battery System

SAE International Journal of Alternative Powertrains

HK Semitech Co., LTD.-Taeyeon Lee, Byungsub Jung
Yura Corporation-Sang-Ryong Lee, Ho-Kyung Kim, Sa-Heun Wie, Dae-Hwan Kwon, Min-Chul Joo
  • Journal Article
  • 2013-01-1764
Published 2013-04-08 by SAE International in United States
This paper proposes a smart main relay assembly or power relay assembly for xEV battery system. The role of main relay assembly is to connect and disconnect main high voltage battery and loads including the inverter. Current main relay is usually a special electro-mechanical relay which has a gas chamber to suppress electrical sparks between relay contacts for switching high current safely. The gas-chambered electro-mechanical relay is relatively too heavy and bulky to decrease design flexibility and may worsen fuel economy.The proposed smart main relay assembly uses IGBT (insulated gate bipolar transistor) for transient states to switches on or off, and uses relays for steady states to connect or disconnect current. As no spark induces to relay contacts directly with the proposed method, conventional electro-mechanical relays without gas-chambers can be used. Therefore the mass and volume can be reduced to increase gas mileage and also reduce the material cost. Using a current sensor in the assembly, a fail-safe diagnosis function which detects and disconnects an abrupt change of high current up to a given limit,…
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Investigation of the Impact Phenomenon During Minor Collision

SAE International Journal of Alternative Powertrains

Japan Automobile Research Institute-Masashi Takahashi, Masaru Takabayashi, Hiroyuki Mitsuishi
  • Journal Article
  • 2013-01-1545
Published 2013-04-08 by SAE International in United States
ISO 12405-1,2 specifies international testing standards for lithium-ion batteries for vehicles. In the mechanical shock test is used to determine if the battery is damaged due to the shock imposed when the vehicle runs over a curb or similar minor accidents. Therefore, we conducted minor collision tests against a curb using an actual vehicle and compared the test results with the conditions specified in ISO 12405-1,2. The results confirmed that the impulse wave obtained using an actual vehicle within the range of the test in this study differs from the shape of the impulse wave specified in ISO 12405-1,2.
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Development of a New Two-Motor Plug-In Hybrid System

SAE International Journal of Alternative Powertrains

Honda R&D Co., Ltd.-Naritomo Higuchi, Yoshihiro Sunaga, Masashi Tanaka, Hiroo Shimada
  • Journal Article
  • 2013-01-1476
Published 2013-04-08 by SAE International in United States
A highly efficient two-motor plug-in hybrid system is developed to satisfy the global demands of CO2 reduction. This system switches three operation modes, what is called “EV Drive”, “Hybrid Drive” and “Engine Drive”, to maximize fuel efficiency according to the driving condition of the vehicle. Practical plug-in EV (Electric Vehicle) capability is also realized by adding a high-power on-board charger and a high capacity Li-ion battery to the original system.The outlines of the system components including a newly developed Atkinson cycle engine, a highly efficient electric coupled CVT (Continuously Variable Transmission) with built-in motor and generator, an integrated PCU (Power Control Unit) and an exclusive battery for plug-in HEV (Hybrid Electric Vehicle) are described in this paper.In addition to the switching of three driving modes and the efficiency improvement of each device, cooperative control of the hybrid system is introduced.By installing this system in 2014 Accord plug-in hybrid, superior fuel economy is achieved with values of 46 MPG in CS (Charge Sustaining) mode and 115 MPGe (Miles Per Gallon equivalent) in CD (Charge Depleting) mode.…
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Fire Fighting of Li-Ion Traction Batteries

SAE International Journal of Alternative Powertrains

DEKRA Automobil GmbH-Markus Egelhaaf, David Kress, Dieter Wolpert, Thomas Lange
Daimler AG-Rainer Justen
  • Journal Article
  • 2013-01-0213
Published 2013-04-08 by SAE International in United States
The number of full electric and hybrid electric vehicles is rapidly growing [1][2][3]. The new technologies accompanying this trend are increasingly becoming a focal point of interest for rescue services. There is much uncertainty about the right techniques to free trapped occupants after an accident. The same applies to vehicle fires. Can car fires involving vehicles with a lithium ion traction battery be handled in the same way as conventional vehicle fires? Is water the right extinguishing agent? Is there a risk of explosion?There are many unanswered questions surrounding the topic of electric vehicle safety. The lack of information is a breeding ground for rumours, misinformation and superficial knowledge. Discussions on various internet platforms further this trend.Tests were conducted on three lithium ion traction batteries, which were fuel-fired until burning on their own. The batteries were then extinguished with water, a surfactant and a gelling agent. The temperatures of the batteries and the required amount of water were recorded.This paper presents the results of the tests and provides information which can be forwarded to fire…
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Thermal Management of Vehicular Payloads Using Nanofluid Augmented Coolant Rail - Modeling and Analysis

SAE International Journal of Alternative Powertrains

Fan He, David Ewing, Joshua Finn, John Wagner, Lin Ma
  • Journal Article
  • 2013-01-1641
Published 2013-04-08 by SAE International in United States
Various payloads, such as electronic systems, have become an integral part of modern military ground vehicles. These payloads often feature high thermal density that need to be effectively managed, especially under demanding operating conditions, to maintain system reliability. This paper describes the modeling and analysis of a nanofluid augmented coolant rail combined with thermoelectric devices to address the cooling challenges posed by these payloads. A sensitivity analysis has been performed to investigate the nanoparticle enhancement model. Numerical results obtained show that the convective heat transfer coefficient can be enhanced by up to 16% with the augmentation of nanoparticles into the base fluid. The results also show that the peak computer temperature is rather insensitive to the complexity of the model used and that the proposed system provides cooling performance which would not be possible with traditional air-cooled heat sinks.
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Scalable Complexity Simulation in the Electric Vehicle Thermal Management Development Process

SAE International Journal of Alternative Powertrains

Engineering Center Steyr GmbH & CoKG-Christian Rathberger, Alexander Lichtenberger
Magna Powertrain-Christoph M. Stroh
  • Journal Article
  • 2013-01-1777
Published 2013-04-08 by SAE International in United States
In order to provide efficient thermal management for an electric vehicle, the development of the cooling and conditioning system has to start early on in the overall product development cycle. This means that the first simulation models have to make do with relatively few actual data, mostly based on concepts and design studies. Accordingly the possible results are mainly useable for early on feasibility assessments.With more data and more details available, these simulation models gradually evolve, until in the end the overall cooling system is modeled with a relatively high level of detail. This allows e.g. transient analysis of warm-up or cool-down runs, simulation of driving cycles, implementation and optimization of control strategies.Although this basic workflow is true both for ICE and electric vehicles, for the latter specific topics like battery thermal management and HVAC integration add to the overall complexity. Especially the electric battery with its strong temperature constraints and its complex internal structure normally requires several modeling steps with increasing levels of detail during the development process.We want to discuss:Which data is required…
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Multi-Physics Numerical Analysis of PEMFC for Automobile Application

SAE International Journal of Alternative Powertrains

Nissan Motor Company, Ltd.-Yuichiro Tabuchi, Toshikazu Kotaka
The Pennsylvania State University-Chao-Yang Wang
  • Journal Article
  • 2013-01-0476
Published 2013-04-08 by SAE International in United States
Polymer Electrolyte Membrane Fuel Cell (PEMFC) is regarded as a potential alternative clean energy source for automobile applications. Key challenges to the acceptance of PEMFC for automobiles are the cost reduction, improvement in power density for its compactness, and cold-start capability. High current density operation is a promising solution for them. However, high current density operation under normal and sub-zero temperature requires more oxygen flux for the electrochemical reaction in the catalyst layer, and it causes more heat and water flux, resulting in the significant voltage losses. So, the theoretical investigation is very helpful for the fundamental understanding of complex transport phenomena in high current density operation under normal and sub-zero temperature. In this study, the numerical model was established to elucidate the impacts of mass transport phenomena on the cell performance through the numerical validation with experimental and visualization results. The results indicated that the higher current density operation causes non-uniform reaction distribution, resulting in lower cell performance under normal temperature and less accumulated produced water under sub-zero temperature. They also quantitatively indicated the…
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The Measured Impact of Vehicle Mass on Road Load Forces and Energy Consumption for a BEV, HEV, and ICE Vehicle

SAE International Journal of Alternative Powertrains

Argonne National Laboratory-Henning Lohse-Busch
ECOtality North America-Jeremy Diez
  • Journal Article
  • 2013-01-1457
Published 2013-04-08 by SAE International in United States
The U.S. Department of Energy's Office of Energy Efficiency & Renewable Energy initiated a study that conducted coastdown testing and chassis dynamometer testing of three vehicles, each at multiple test weights, in an effort to determine the impact of a vehicle's mass on road load force and energy consumption. The testing and analysis also investigated the sensitivity of the vehicle's powertrain architecture (i.e., conventional internal combustion powertrain, hybrid electric, or all-electric) on the magnitude of the impact of vehicle mass. The three vehicles used in testing are a 2012 Ford Fusion V6, a 2012 Ford Fusion Hybrid, and a 2011 Nissan Leaf. Testing included coastdown testing on a test track to determine the drag forces and road load at each test weight for each vehicle. Many quality measures were used to ensure only mass variations impact the road load measurements. Chassis dynamometer testing was conducted over standard drive cycles on each vehicle at multiple test weights to determine the fuel consumption or electrical energy consumption impact caused by change in vehicle mass. The road load…
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