Terms:
SAE International Journal of Commercial Vehicles
AND
6
AND
2
The SAE MOBILUS platform will continue to be accessible and populated with high quality technical content during the coronavirus (COVID-19) pandemic. x
Show Only

Collections

File Formats

Content Types

Dates

Sectors

Topics

Authors

Publishers

Affiliations

Events

   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Reducing Vehicle Drag Force Through a Tapered Rear Side Wall

SAE International Journal of Commercial Vehicles

UKM-Rozli Zulkifli
Universiti Kebangsaan Malaysia-Shahrir Abdullah
  • Journal Article
  • 2013-01-9020
Published 2013-10-20 by SAE International in United States
Recent fluctuation in oil prices has generated interest in fuel-efficient vehicles, especially their aerodynamic profile. The literature indicates that turbulent wakes that form at the rear end of the vehicle contribute to vehicle drag in a major way. Minor studies have addressed the effects of rear-end wall angle to the drag force through effecting the wake behind the vehicle; however, this study assesses the reduction of drag using angular side walls. A previous simulation of external airflow over Ahmed's body was investigated, utilizing the k-ω SST models. Different angles of side walls were analyzed, and a maximum 36.85% reduction in drag coefficient was achieved using an angular rear side wall. The turbulent model was validated and the effectiveness of angular rear side walls thus proven. The study then simulated the flow for a road vehicle model to investigate the real world effect of angular rear side walls. The results showed up to 11.39% reduction in drag coefficient, supporting the effect of angular rear walls on reducing drag coefficient.
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Intelligent Predictive Cruise Control Application Analysis for Commercial Vehicles based on a Commercial Vehicles Usage Study

SAE International Journal of Commercial Vehicles

Kingston University-Andrzej Ordys
Kingston University London-Gordana Collier
  • Journal Article
  • 2013-01-9022
Published 2013-10-20 by SAE International in United States
With the introduction of advanced digital road maps, which include information on the slope and curve radius of the highways, predictive control for standard and hybrid commercial vehicles, based on these maps, is about to be released by the vehicle manufacturers. For example, intelligent predictive cruise control has been announced for introduction in 2012 by Scania and Daimler. In addition, hybrid commercial city buses like MAN's Lion's City Hybrid have already been implemented. But the question remains about the type of vehicle suitable for the implementation of predictive intelligent concepts, due to the high investment cost compared to the sometimes relatively low operating cost savings. This study analyses usage and performance data collected from approximately 20,000 commercial vehicles, which include long distance trucks, distribution trucks, city buses and coaches, in order to answer the question which vehicle types should be equipped with intelligent predictive cruise control considering an economic reasonable return on investment.
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Gearshift Actuator Dynamics Predictions in a Dual Clutch Transmission

SAE International Journal of Commercial Vehicles

Western Michigan University-John Manyala
  • Journal Article
  • 2013-01-9021
Published 2013-10-20 by SAE International in United States
Although hybrid variants of Automated Mechanical Transmissions such as the Dual Clutch Transmissions are less affected by driveline torque interrupts, actuator dynamics is very critical in the speed of gear pre-selection and during multiple gear shifts. To avoid torque interrupts, such systems require precise gearshift duration hence the actuators are expected to have fast, stable and predictable responses. However, actuator dynamics and controls remain barriers to attaining the full benefits of such complex systems, demanding precise timing and coordination of the gearshifts alongside the clutches engagement and disengagement. To overcome such challenges, a dynamic model of an electro-hydraulic gearshift actuator, the synchronizer and the shift fork has been developed. The model predicts the gearshift actuator dynamics for a given set of input parameters, which can be correlated against experimental data. The significance of the work is that an efficient and robust means of improving the gearshift quality of a DCT has been devised.
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Investigations on Valve Recession of a Commercial Vehicle Engine

SAE International Journal of Commercial Vehicles

SPSU, Udaipur-Lakshmi Prasad Boggupalli
  • Journal Article
  • 2013-01-9019
Published 2013-10-20 by SAE International in United States
Investigations on valve recession of a commercial vehicle engine inlet valve are done. Failure analysis of inlet valve of a six cylinder commercial vehicle engine developing power of 155 BHP is carried out using the software tools IDEAS and TYCON. Failed engine valves are investigated and concluded that the mode of failure of most of them is valve recession, the possible factors responsible for the valve failure are analyzed including the metallurgical properties of the valve. Combustion force, impact force during closure of the valve are the major factors responsible for valve recession. The valve seat angle is considered in the analysis to find if the change in this angle is helpful in increasing the life of the valve. The prevailing wear mechanism has been shown related to the critical operating conditions such as valve closing velocity, combustion load, valve misalignment relative to the seat insert and seat insert material choice. Besides this, the wear volume of the valve face was found to change with valve material, engine operation conditions, geometries, and dynamics changed. Besides…
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Load Estimation of an Open-Link Locomotion Module for Robotic and Commercial Multi-Wheel Applications

SAE International Journal of Commercial Vehicles

General Physics Institute-Tatiana I. Ksenevich
Moscow Bauman State Tech Univ-Boris Beloousov
  • Journal Article
  • 2013-01-2358
Published 2013-09-24 by SAE International in United States
An open-link locomotion module, comprising a driving wheel with an electric motor, a system of electro-hydraulic suspension, and an electro-hydraulic power steering system, is presented in this paper as the basis for the modular design of unmanned (robotic) ground vehicles. The open-link-type configuration allows the module to be functionally integrated and engineered with a system of similar modules and thus virtually allows to compile vehicles with any required number of driving wheels. The overall dimensions and carrying capacity of the tire used in the module, as well as technical characteristics of the suspension and power steering systems make possible to employ the module for commercial ground vehicle applications.This paper considers technical issues related to designing the locomotion module. In particular, the interaction of the suspension and steering systems is studied while the systems form the normal reaction of the wheel and influence the resistance moment in the tire-road contact patch. The suspension characteristics influence the wheel normal reaction, tire deflections, and the over roll area of the tire patch. An increased tire patch area has…
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

A Comparison of Full Scale Aft Cavity Drag Reduction Concepts With Equivalent Wind Tunnel Test Results

SAE International Journal of Commercial Vehicles

ATDynamics-Jeff Grossman, Jared Niemiec, Andrew Smith, Charles M. Horrell
Clarkson University-Joshua P. Kehs, Kenneth D. Visser
  • Journal Article
  • 2013-01-2429
Published 2013-09-24 by SAE International in United States
Comparison studies have been conducted on a 1:16th scale model and a full scale tractor trailer of a variety of sealed aft cavity devices as a means to develop or enhance commercial drag reduction technology for class 8 vehicles. Various base cavity geometries with pressure taps were created for the scale model. The studies confirmed that length has an important effect on performance. The interaction of the boat-tailed aft cavity with other drag reduction devices, specifically side skirts, was investigated with results showing no discernable drag performance interaction between them. Overall, the experiments show that a boat-tailed aft cavity can reduce the drag up to 13%. Full-scale tests of a commercially derived product based on these scale tests were also completed using SAE Type II testing procedures. Full-scale tests indicated a fuel savings of over 6.5%. The implementation of these devices is shown to be a viable, effective and economical way to reduce fuel consumption on ground transport vehicles.
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

In-Use and Vehicle Dynamometer Evaluation and Comparison of Class 7 Hybrid Electric and Conventional Diesel Delivery Trucks

SAE International Journal of Commercial Vehicles

National Renewable Energy Laboratory-Jonathan Burton, Kevin Walkowicz, Petr Sindler, Adam Duran
  • Journal Article
  • 2013-01-2468
Published 2013-09-24 by SAE International in United States
This study compared fuel economy and emissions between heavy-duty hybrid electric vehicles (HEVs) and equivalent conventional diesel vehicles. In-use field data were collected from daily fleet operations carried out at a FedEx facility in California on six HEV and six conventional 2010 Freightliner M2-106 straight box trucks. Field data collection primarily focused on route assessment and vehicle fuel consumption over a six-month period. Chassis dynamometer testing was also carried out on one conventional vehicle and one HEV to determine differences in fuel consumption and emissions. Route data from the field study was analyzed to determine the selection of dynamometer test cycles. From this analysis, the New York Composite (NYComp), Hybrid Truck Users Forum Class 6 (HTUF 6), and California Air Resource Board (CARB) Heavy Heavy-Duty Diesel Truck (HHDDT) drive cycles were chosen. The HEV showed 31% better fuel economy on the NYComp cycle, 25% better on the HTUF 6 cycle and 4% worse on the CARB HHDDT cycle when compared to the conventional vehicle. The in-use field data indicates that the HEVs had around 16%…
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Fuel Cell Auxiliary Power Units for Heavy Duty Truck Anti-Idling

SAE International Journal of Commercial Vehicles

AVL LIST GmbH-Juergen Rechberger
Eberspächer Climate Control Systems-Andreas Kaupert
  • Journal Article
  • 2013-01-2470
Published 2013-09-24 by SAE International in United States
The DESTA project, funded by the European Commission under the FCH JU program, is a collaborative effort of AVL List GmbH, Eberspächer Climate Control Systems, Topsoe Fuel Cell (TOFC), Volvo and Forschungszentrum Jülich to bring fuel cell based auxiliary power units (APU) for heavy duty truck idling elimination closer to the market. Within this project Solid Oxide Fuel Cell (SOFC) technology is used, which enables the use of conventional diesel fuel. During the project the technology is significantly optimized and around 10 APU systems are thoroughly tested. In 2014 a vehicle demonstration on board of a US type Volvo class 8 truck will be performed.
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

UniTire Model for Tire Forces and Moments under Combined Slip Conditions with Anisotropic Tire Slip Stiffness

SAE International Journal of Commercial Vehicles

ASCL,Jilin University-Nan Xu, Konghui Guo, Xinjie Zhang
  • Journal Article
  • 2013-01-2362
Published 2013-09-24 by SAE International in United States
The tire mechanics characteristics are essential for analysis, simulation and control of vehicle dynamics. This paper develops the UniTire model for tire forces and moments under combined slip conditions with anisotropic tire slip stiffness.The anisotropy of tire slip stiffness, which means the difference of tire longitudinal slip stiffness and cornering stiffness, will cause that the direction of tire resultant shear stress in adhesion region is different from that in sliding region. Eventually the tire forces and moments under combined slip conditions will be influenced obviously. The author has proposed a “direction factor” before to modify the direction of resultant force in the tire-road contact patch, which can describe tire forces at cornering/braking combination accurately. However, the aligning moments which are very complicated under combined slip conditions are not considered in previous analysis.The simplified physical tire model is introduced firstly in this paper to analyze the tire mechanics characteristics under combined cornering/braking situations, containing the tire forces and aligning moments. Then considering the influence of anisotropic tire slip stiffness and the expression of “direction factor”, a…
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

A Statistical Characterization of School Bus Drive Cycles Collected via Onboard Logging Systems

SAE International Journal of Commercial Vehicles

National Renewable Energy Laboratory-Adam Duran, Kevin Walkowicz
  • Journal Article
  • 2013-01-2400
Published 2013-09-24 by SAE International in United States
In an effort to characterize the dynamics typical of school bus operation, National Renewable Energy Laboratory (NREL) researchers set out to gather in-use duty cycle data from school bus fleets operating across the country. Employing a combination of Isaac Instruments GPS/CAN data loggers in conjunction with existing onboard telemetric systems resulted in the capture of operating information for more than 200 individual vehicles in three geographically unique domestic locations. In total, over 1,500 individual operational route shifts from Washington, New York, and Colorado were collected.Upon completing the collection of in-use field data using either NREL-installed data acquisition devices or existing onboard telemetry systems, large-scale duty-cycle statistical analyses were performed to examine underlying vehicle dynamics trends within the data and to explore vehicle operation variations between fleet locations. Based on the results of these analyses, high, low, and average vehicle dynamics requirements were determined, resulting in the selection of representative standard chassis dynamometer test cycles for each condition.In this paper, the methodology and accompanying results of the large-scale duty-cycle statistical analysis are presented, including graphical and…
Annotation ability available