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SAE International Journal of Commercial Vehicles
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Investigation on Underhood Thermal Analysis of Truck Platooning

SAE International Journal of Commercial Vehicles

Argonne National Laboratory-Surya Narayana Prasa Vegendla, Tanju Sofu
Cummins, Inc.-Rohit Saha, Long-Kung Hwang, Mahesh Madurai Kumar
  • Journal Article
  • 02-11-01-0001
Published 2018-03-22 by SAE International in United States
This paper presents a combined aero-thermal computational fluid dynamic (CFD) evaluation of platooning medium duty commercial vehicles in two highway configurations. Thermal analysis comparison is made between an approach that includes vehicle drag reduction on engine heat rejection and one that does not by assuming a constant heat rejection based on open road conditions. The paper concludes that accounting for aerodynamic drag reduction on engine heat load provides a more real world evaluation than assuming a constant heat load based on open road conditions. A 3D CFD underhood thermal simulations are performed in two different vehicle platooning configurations; (i) single-lane and (ii) two-lane traffic conditions. The vehicle platooning consists of two identical vehicles, i.e. leading and trailing vehicle. In this work, heat exchangers are modeled by two different heat rejection rate models. In the first model, a constant heat rejection rates are considered as similar to no-traffic vehicle condition. In the other model, a varied heat rejection rates are implemented by considering an aerodynamic influence on fuel consumption rates. In a constant heat rejection rate…
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Investigation of Passive Porosity as a Means for Bluff-Body Drag Reduction

SAE International Journal of Commercial Vehicles

Brunel University-Alvin Gatto
Cambridge University-Holger Babinsky
  • Journal Article
  • 02-11-01-0006
Published 2018-03-16 by SAE International in United States
An investigation into the capability of passive porosity to reduce the drag of a bluff-body is presented. This initial work involves integrating varying degrees of porosity into the side and back faces of a small-scale model to determine optimum conditions for maximum drag reduction. Both force and pressure measurements at differing degrees of model yaw are presented, with the conditions for optimum performance, identified. At a length-based Reynolds number of 2.3 × 106, results showed a maximum drag reduction of 12% at zero yaw when the ratio of the open area on the back face relative to the side faces was between two and four. For all non-zero yaw angles tested, this ratio reduced to approximately two, with the drag benefit reducing to 6% at 10.5 degrees. From a supplementary theoretical analysis, calculated optimum bleed rate into the base for maximum drag reduction, also showed reasonable agreement to other results reported previously.
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Design and Implementation of a Hybrid Fuzzy-Reinforcement Learning Algorithm for Driver Drowsiness Detection Using a Driving Simulator

SAE International Journal of Commercial Vehicles

K. N. Toosi University of Technology-Armin Kassemi Langroodi, Ali Nahvi
  • Journal Article
  • 02-11-01-0005
Published 2018-03-08 by SAE International in United States
Driver drowsiness is the cause of many fatal accidents all over the world. Many research works have been conducted on detecting driver drowsiness for more than half a century, but statistical data show that such accidents have not decreased significantly. Most researchers have focused on using certain sensors and extracting their relevant features. However, there has been no research work on developing an algorithm to detect driver drowsiness independently from the input type. In this paper, a hybrid fuzzy-reinforcement learning drowsiness detection algorithm is presented. This algorithm is flexible to work with any number and any kind of data related to driver alertness. It estimates the level of alertness based on an arbitrary number of inputs. The algorithm extracts driving patterns specific to each driver and determines driver’s level of drowsiness using a continuous numerical variable rather than a discrete variable. To evaluate the algorithm, only six features related to only steering wheel angle and velocity are used. The accuracy of the user-specific data is 81.1% validated with the Observer Rating of Drowsiness criterion. This…
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Aerodynamic Analysis of Cooling Airflow for Different Front-End Designs of a Heavy-Duty Cab-Over-Engine Truck

SAE International Journal of Commercial Vehicles

Chalmers University of Technology-Helena Martini, Lennart Lofdahl
Volvo Group Trucks Technology-Peter Gullberg
  • Journal Article
  • 02-11-01-0003
Published 2018-04-07 by SAE International in United States
Improving the aerodynamics of heavy trucks is an important consideration in the strive for more energy-efficient vehicles. Cooling drag is one part of the total aerodynamic resistance acting on a vehicle, which arises as a consequence of air flowing through the grille area, the heat exchangers, and the irregular under-hood area. Today cooling packages of heavy trucks are dimensioned for a critical cooling case, typically when the vehicle is driving fully laden, at low speed up a steep hill. However, for long-haul trucks, mostly operating at highway speeds on mostly level roads, it may not be necessary to have all the cooling airflow from an open-grille configuration. It can therefore be desirable for fuel consumption purposes, to shut off the entire cooling airflow, or a portion of it, under certain driving conditions dictated by the cooling demands. In Europe, most trucks operating on the roads are of cab-over-engine type, as a consequence of the length legislations present. However, there are new directions from the European Union, which would permit slightly longer vehicles to improve aerodynamics…
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CFD Windshield Deicing Simulations for Commercial Vehicle Applications

SAE International Journal of Commercial Vehicles

Navistar, Inc.-Krystian J. Link
Northern Illinois University-Nicholas A. Pohlman
  • Journal Article
  • 02-11-01-0002
Published 2018-04-06 by SAE International in United States
Windshield deicing performance is a key metric for HVAC system development and optimization within the sphere of commercial vehicle design. The primary physical parameters that drive this metric are pressure drops in the HVAC ducting, flow rate of the air through the system, and the transient vent temperature rise affected by engine coolant warm-up. However, many design engineers also have to take underhood and instrument panel (IP) space constraints into consideration while trying to optimize a new HVAC system design. This study leverages historical deicing simulation methodologies in conjunction with modern computational horsepower so as to optimize the HVAC ductwork in the studied commercial truck at the beginning of the design phase. By iterating on a design in the computational domain under steady-state and transient flow and thermal conditions, a robust HVAC system design can be created even prior to the prototyping stage of development. Furthermore, when the vehicle runs through an experimental regime, the design engineer has reasonable certainty of meeting their targets with respect to the HVAC system’s deicing performance. By completing steady…
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Methodology for Developing a Diesel Exhaust After Treatment Simulation Tool

SAE International Journal of Commercial Vehicles

Technical University of Denmark-Tine Christiansen, Johanne Jensen, Andreas Åberg, Jens Abildskov, Jakob Huusom
  • Journal Article
  • 02-11-01-0004
Published 2017-09-16 by SAE International in United States
A methodology for the development of catalyst models is presented. Also, a methodology of the implementation of such models into a modular simulation tool, which simulates the units in succession, is presented. A case study is presented illustrating how suitable models can be found and used for simulations. Such simulations illustrate the behavior of the individual units and the overall system. It is shown how, by simulating the units in succession, the entire after treatment system can be tested and optimized, because the integration makes it possible to observe the effect of the modules on one another.
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