Your Selections

SAE Commercial Vehicle Engineering Congress & Exhibition
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.

The Effect of Flow Forces Compensating Profile on the Metering Characteristics of a Conical Seat Valve

DIMEC – University of Modena and Reggio Emilia-M. Borghi, M. Milani, F. Paltrinieri
Published 2004-10-26 by SAE International in United States
This paper studies the influence of the discharge chamber geometrical parameters on the steady-state characteristics behavior of a conical seat valve having compensating profile.More in details, starting from the analysis of the experimental behavior of an actual valve showing inefficient characteristic curves, the metering openings leading to the transition from under to over compensation are individuated.Then, a 3D CFD steady-state, incompressible and isothermal analysis is involved, mainly to evidence the valve discharge coefficient and flow-forces variations with operating conditions.After, two alternative valve configurations, presenting a low pressure region designed to optimize the flow-forces compensation, are characterized through the 3D CFD analysis.
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

ToughMet® Alloy: Improving Thrust Bearing Performance Through Enhanced Material Properties

Brush Wellman Inc.-David Krus, W. Raymond Cribb
Published 2004-10-26 by SAE International in United States
We present standardized test results indicating that ToughMet® copper-nickel-tin alloy will outlast traditional transmission thrust bearing materials without increasing frictional power loss or endangering mating components. Sleeve bearing tests show the PV (bearing pressure × linear speed) limit of ToughMet is more than three times that of leaded tin bronze. In thrust washer wear rate testing ToughMet provided 4 and 14 times reduction in wear rate as compared to leaded tin bronze at speeds and pressures found in transmissions. The performance advantage is related to differences in physical and mechanical properties between the two materials.
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

A Web Based Finite Element Frequency Analysis Program for Designing a Driveline System

DANA Corp.-Murali M. R. Krishna, Jun Yoshioka, Manish Sharma
Published 2004-10-26 by SAE International in United States
A web based software program has been developed to do a Finite Element (FE) analysis of a simplified driveline system. In the past, an expert analyst had to make a Finite Element Model, analyze and then report results. It has been observed that this process is time consuming besides the difficulties of doing quick parametric studies, geographical location of designers, analysts, etc. The web-based software program aims to solve these issues. The designer could get analytical & Finite element results anywhere around the world (where the designer has access to the web) without any expertise in FE modeling. This software is a joint effort of Engineering and Information Technology (IT) software groups. It is based on Active Server Page (ASP) technology and MSC/NASTRAN technologies combined. Input data deck is prepared from user inputs and submitted over the internet to a remote system, solved and results are retrieved and plots shown in minutes, instead of days earlier. The designer can quickly do parametric studies and also get reports. This web-based technology has a great potential for…
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

A Vehicle Parameter Study on Crosswind Sensitivity of Buses

Scania Commercial Vehicles AB-Peter Eriksson
Scania Commercial Vehicles AB KTH Vehicle Dynamics, Sweden-Magnus Juhlin
Published 2004-10-26 by SAE International in United States
Incidents with heavy vehicles have brought the issue of directional stability of buses under the influence of crosswind gusts into focus. In this work the directional stability of buses when exposed to crosswind gusts has been investigated by performing a parameter study on a MBS vehicle-model combined with a generalised crosswind gust model. The study shows that the most important parameters are the magnitude of the yaw moment overshoot at gust entry and the weight distribution in combination with the location of the aerodynamic pressure centre.
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Improving Spool Valve Operating Effort Using CFD

HUSCO International, Inc.-Roger Yang
Published 2004-10-26 by SAE International in United States
Hydraulic oil flow and flow induced forces inside hydraulic spool valves have been studied using a commercially available Computational Fluid Dynamics (CFD) software package with an aim of improving hydraulic spool valve operating efforts. The main objective is to investigate flow induced forces on the spool with a range of different geometries or operating conditions and therefore to minimize or utilize their effect on spool effort. This CFD problem was treated as incompressible, turbulent, steady and adiabatic or isothermal. Integration of solved pressure field from a commercial CFD solution over related a valve component surface area was used to integrate the desirable flow induced forces. Additional viscous drag forces on the spool effect on total spool operating effort have also been investigated. The focus in this article is mainly based on studies for open center flow type four-way spool valves in cases such that the hydraulic oil flow direction towards spool. Some other spool metering cases will also be presented. CFD results are compared to experimental results with overall good correlation.
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

A Multi-Level Approach for the Validation of a Tractor-Semitrailer Ride and Handling Model

International Truck and Engine Corp.-Stefano J. Cassara, David C. Anderson, J. Magnus Olofsson
Published 2004-10-26 by SAE International in United States
The accurate prediction of commercial-vehicle ride and handling performance with computer simulation tools is dependent on the level of correlation between the computer model and experimental data. Correlating vehicle attributes to physical test data is often challenging due to the large number of degrees of freedom - and, correspondingly, the large number of tunable parameters - typically required to accurately model vehicle behavior. A high level of interaction between input parameters and vehicle attributes further complicates the task. As a result, this type of correlation is a multi-objective optimization exercise in which the judicious planning of supporting test activity is critical to achieving the right level of model accuracy with an acceptable amount of resource investment.This paper discusses the methodology implemented in the validation of a tractor-semitrailer ADAMS model for both ride and handling simulations and presents the results obtained. A select set of vehicle-, subsystem- and component-level tests was performed to provide a basis for subsystem correlation and subsystem-interaction studies at the vehicle level. These included suspension characterization, modal testing, moment of inertia measurements…
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Designing Single-Purpose or Multi-Purpose Engines for On-Road and Non-Road Use - A Platform Approach

AVL List GmbH-Franz X. Moser, Gunnar Stein
Published 2004-10-26 by SAE International in United States
The paper gives an overview of the partially extremely complex problem when looking into commonalities and differences of the three main application areas of engines and powertrains - automotive, agricultural tractors, and industrial engines, the last being predominantly but not exclusively focused on construction equipment.The modern “platform” approach has been used in the automotive world to a large extent and the learned experiences may be of interest for the agricultural tractors and/or the construction equipment manufacturers. On the other hand the truck engine engineers and manufacturers will learn more about the special requirements of the tractor and the industrial engines fields, and thus influence concepts and development procedures and also the production of the automotive engines which in many cases serve as the basis for derivate engines. The question will be raised whether there are benefits of the “single-purpose engine” as compared to the “multi-purpose or universal engine”. What will be the cost implications of the two main approaches and how should the production be organized and optimized for the two ways? A major role…
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

The Impact of the Dynamic Tractor-Semitrailer Interaction on the Ride Behaviour of Fully-Laden and Unladen Trucks

Helwan University, Egypt-I. M. Ibrahim
Leeds University, UK-D. A. Crolla, D. C. Barton
Published 2004-10-26 by SAE International in United States
In this paper, the effect of the dynamic interaction between tractor and semitrailer on the ride behaviour of heavy good vehicles is investigated. A multi-body model is constructed for a 4-axle tractor-semitrailer vehicle with flexible frames and excited by random road irregularities. The modal parameters of the connected frames are calculated using the FEM (Finite Element Method), as an integrated free vibrating structure, and incorporated with the equations of motion of the whole vehicle which are generated using the Lagrange energy approach.Frequency response analysis is carried out for random road excitations to evaluate the vehicle ride dynamics. In order to give a broad overview of the vehicle ride quality, different loading conditions are considered in the computer simulation. The results showed that the acceleration levels of vehicle components are significantly increased when the effect of an empty semitrailer is considered within the vehicle model. This effect is suppressed by reducing the stiffness and damping coefficients of the suspension systems of the tractor and semitrailer. Practically, a change in the suspension stiffness can be achieved using…
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Drive Line Control for Off-Road Vehicles Helps to Save Fuel

Institute for Aircraft Systems Engineering, Technical University of Hamburg-Harburg, Germany-Jean-Claude Ossyra, Monika Ivantysynova
Published 2004-10-26 by SAE International in United States
A new control concept was developed to minimize the power losses of a hydrostatic drive line for off-road vehicles. The drive line control concept is based on two separate closed loop controls, one for the hydrostatic transmission and another for the combustion engine. The command values for both control loops are calculated under consideration of the characteristic curves of the combustion engine and the losses within the hydrostatic transmission, using an on-line optimization procedure. This paper discusses the benefits of this control concept based on a comparison of typical realistic driving manoeuvres. Objective of the investigations for different output powers is the potential of fuel savings under different operating conditions. A hardware-in-the-loop test rig for the investigated hydrostatic propel drive is used for the experimental validation.
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

The Novacab System to Reduce Energy Consumption for HVAC in Bus and Commercial Van Applications

Groupe Enerstat Inc.-Stéphane Bilodeau
Published 2004-10-26 by SAE International in United States
The heating ventilating and air conditioning systems (HVAC systems) in use today on internal combustion vehicles do not lend themselves to efficient application in vehicles having long idling period, especially in the buses and commercial vehicles market.An integrated climate control system has been developed by Groupe Enerstat over the past seven years. Applying a high-efficiency thermal storage technology (based on phase change of specific materials), the Novacab Climate Control System has been implemented in commercial trucks and buses to reduce idling (for “off road and off engine” heating and cooling). Comprehensive performance analyses and testing of the high-performance heat pump, but also a comparison with other systems have highlighted many benefits of using the technology (improved fuel economy by reducing vehicle idle and allowing for engine longer shut-off conditions).This article presents the system and shows the results (in terms of reduction in energy consumption and emissions) of the implementation with monitored on-road data in commercial truck applications.
Annotation ability available