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2017-06-02
Article
Kenworth and Peterbilt vehicles will feature a new proprietary front axle using an innovative tapered kingpin roller bearing, beginning in the third quarter of 2017.
2017-06-01
Magazine
Tackling NVH one dB per day New tools and technologies are helping engineers reduce vehicle Noise, Vibration and Harshness. Artificial intelligence becomes a reality Automakers could be among the leaders in deploying AI in free-standing, high-reliability environments. But developers must determine how to mitigate undesirable side-effects. Lidar: autonomy's mission-critical component Automated-driving capability likely won't happen without Lidar. But what technology-and at what price? Formula One goes longer, lower, wider for 2017 New rules make the cars faster and more aggressive-looking, with a wider track, wider tires and bigger wings. Editorial: Core Ford, New Ford...OneFord? SAE Standards News Seeking a common language for vehicle automation Supplier Eye Are you innovating for NVH?
2017-05-30
Technical Paper
2017-01-5002
James Bradley Skarie
Abstract Antilock braking systems (ABS) are inherently limited by the static coefficient of friction (µ) between a vehicle’s tires and the road surface. This paper explores a unique active safety concept, Integrated Coefficient Enhancement (ICE), which works to improve ABS well beyond their present limits. The ICE concept was developed using a basic physics principle: to change µ between two surfaces, at least one of the surfaces must be altered in some way. By quickly deploying a specially designed tractive medium (TM) to aid in directional stability and braking, hazardous situations can be greatly mitigated. This paper describes the features and testing results of this TM and its aerodynamic-mechanical-electronic deployment apparatus. Under all slippery road conditions tested, the developed TM mitigated skidding, with improvements that ranged from 20% to several hundred percent, depending on conditions and deployment rates.
CURRENT
2017-05-30
Standard
J2494/1_201705
This SAE Standard covers general and dimensional specifications for brass bodied reusable Push to Connect tube fittings for use in the piping of vehicular air brake systems. This type of fitting is intended for use with nylon tubing per SAE J844. See SAE J2494-3 for the Performance Requirements of Reusable (Push to Connect) Fittings Intended for Use in Automotive Air Brake Systems and U.S. Department of Transportation, National Highway Traffic Safety Administration (NHTSA) Federal Motor Vehicle Safety Standards (FMVSS) 571.
2017-05-24
Technical Paper
2017-36-0001
Luís Fernando Nuss de Souza, Antônio Carlos de Oliveira, Narã Vieira Vetter
Abstract After the anti-skid brake system (ABS) introduction, mandatory for all vehicles in the Brazilian market, manufacturers have given increasing attention to optimized systems which meet legal and safety requirements. For commercial vehicles, an alternative for the ABS, which presents feasibility, is the configuration 4S/3M (4 wheel-speed sensors and 3 modulator valves) in substitution to the configuration 4S/4M. In other words, application of just one modulator valve to control the brakes of the same axle, front or rear, instead of independent control per each brake of the vehicle. The aim of this paper is to present a performance comparison between a brake system fitted with ABS configuration 4S/3M and an ABS configuration 4S/4M. To this end, both configurations were tested on the same vehicle application in accordance with the Brazilian legislation, CONTRAN 519/15.
2017-05-24
Technical Paper
2017-36-0003
Rafael Paini Pavlak, Patric Daniel Neis, Jean Carlos Poletto, Liu Yesukai de Barros, Ney Francisco Ferreira
Abstract The current study presents some testing procedures which have been designed for friction and noise measurements of brake friction materials using a laboratory-scale tribometer. The uncertainties (errors) and precision of the measurements are also described in this paper. Some case studies related to friction, wear and noise related issues in brake friction materials were chosen to show the respective testing procedures. Through the error study, it was shown that the uncertainties of the lab. test bench are mainly associated with 3 variables: torque, force and sliding radius. The combined uncertainty of the friction measurements is less than or equal to ±1%, considering the typical operating range of the machine. The possibility of using two samples from a single brake pad also contributes to the reliability of the machine test and procedures.
2017-05-24
Technical Paper
2017-36-0004
Wesley Bolognesi Prado, Silvia Faria Iombriller, Jonathan Orsi Chiu, Alexandre Roman
Abstract S-cam brakes concept are largely used by commercial vehicles around the world due to its low cost, easy maintenance and robustness. An important component of s-cam brakes is the slack adjuster, that is responsible for amplify brake chamber forces and assure correct lining and drum clearance. Therefore usually slack adjuster mechanism characteristics are defined only by empiric method considering trial and error tentative. This paper aims to demonstrate a methodology created to develop new air s-cam brakes slack adjuster definition taken in consideration its interface with other brake components. During this study was identified design specification for each component and its influence on adjustment process. It was verified the intrinsic characteristics of slack adjuster mechanism and developed a calculation tool to predict its actuation on the brake. The interface of slack adjuster with other foundation brake components and drum compliance were also studied.
2017-05-24
Technical Paper
2017-36-0005
Diego Severo Antunes, Diego Masotti
Abstract Analytical models used to design most of drum brake systems assume rigid body behavior of shoes and drum, resulting in sinusoidal pressure distribution in the friction interface. This approach leads to various limitations and sometimes incoherent results at typical applications since brake components are highly deformable and the contact pressure distribution plays an important role on the brake system efficiency. This study addresses a numerical analysis of drum brake pressure distribution, using Finite Element Method and considering shoes and drum as flexible bodies. The model validation from experimental procedure, where brake components were instrumented in an inertial dynamometer test. Once the pressure distribution can not be accurately measured, this research uses strain field measurements to calibrate the numerical model. This model is nonlinear, implying in convergence difficulties.
2017-05-24
Technical Paper
2017-36-0006
Claudio Jr. Ferreto, Ademir S. Carvalho, Robson D. A. Abreu, Pedro F. Marinho, Luiz R. Guimarães
Abstract Brake noise causes discomfort to passengers and a perception of reduced vehicle quality. Other types of vehicle noises have been significantly reduced and consequently brake noise and vibration are becoming more perceivable by owners, leading to high warranty costs. It is known in the Brake Industry that the natural frequencies of brake rotors may have a significant participation in disc brake squeal generation, and, a robust process control of this characteristic in the manufacturing gives an important contribution to reduce brake noise. However, recent studies have demonstrated a significant variation of natural frequencies due to manufacturing and this is the outcome of carbon equivalent content in gray cast iron. This paper is concerned with the understanding of this phenomenon and its influence on disc brake noise generation. For this research, it was manufactured two batches of this rotor from two different grades of carbon equivalent.
2017-05-24
Technical Paper
2017-36-0007
Luiz Roberto Guimarães, Robson Demétrius Araújo Abreu, Ademir Carvalho, Claudio Jr. Ferreto
Abstract The improvement of motor’s power requires consequently the improvement in brake system also. The kinetic energy of moving vehicles is transformed in a big part of heat, but there is a part that can be transformed in vibration and sound pressure. One of these vibration and sound pressure complain is known as howl noise. The howl noise complain is very intense and uncomfortable for passengers and pedestrians. Today, the customers spend a lot of money in his vehicles comfort and this disorder can’t occur. This paper presents a methodology which uses Experimental Modal Analysis (EMA) and Operational Modal Analysis (OMA) to survey the dynamic behavior of suspension and brake systems at the howl noise occurrence condition.
2017-05-24
Technical Paper
2017-36-0010
André G. L. Suetti, Carlos Eduardo Correia
Abstract The knowledge of the elastic properties of friction materials is especially important in the development of brake systems. The stiffness of the system directly impacts on the consumption of the fluid during braking and the user interaction with the brake pedal, in addition to being strongly linked to the occurrence or not of certain types of noise. For the analysis of brake pad stiffness, is well known the compressibility equipment, which evaluates the deformation subject to a load in the axial direction. The first stage of the work proves that the compressive deformation of the pad has a non-linear behaviour as a function of the applied force. Based on this non-linearity, tests are carried out on 93 brake pads, where trends between the instantaneous deformation and the final compressibility result are sought.
2017-05-24
Technical Paper
2017-36-0021
Jean Cory de Souza Silva, Juan Carlos Horta Gutierrez
Abstract This work consists in a study about regulations for brake system in Brazil, which aims to show the current scenario, as well as the evolution of the resolutions and technologies. Within the last few years Brazil had a considerable evolution in terms of safety requirements for brake systems. In 2009 an important step was taken when Brazilian Traffic National Consil (Conselho Nacional de Trânsito - CONTRAN), the agency responsible for traffic regulations in Brazil, emitted the resolution N° 312, which established the mandatory use of Anti-lock Brake System (ABS). This obligatoriness was introduced gradually, beginning by passengers cars in 2010, when 8% of the automobiles manufactured in that year should have the system installed as standard item. This percentage would increase until reaching 100% of vehicle production in 2014.
2017-05-24
Technical Paper
2017-36-0020
Luiz Filipe de Medeiros Gomes, Fernanda de Lima Menezes, Ademir de Silva Carvalho, Claudio Junior Ferreto, Luciano Matozo
Abstract The brake system is one of the most important safety systems of the vehicle. So far, several researches are being conducted with the objective of improve its efficiency. In a disc brake, it is the friction between the pads and the rotor the responsible for kinetic energy conversion into heat and brake torque generation. Demanding brake applications, can generate high temperatures levels which can reduce the friction coefficient between pads and rotor, reducing brake efficiency. Thus, the present work aims to evaluate the front disc temperature drop by the installation of a duct on the vehicle frontal bumper to direct the outside air into the wheelhouse This duct has the function to direct the outside air towards to the brake disc. Theoretical studies, Computational Fluid Dynamics (CFD) simulations and experimental dynamometer tests were carried out.
2017-05-24
Technical Paper
2017-36-0016
Mathias Haag, Achim Reich, Angelo Sardá, Michael Wurmlinger-Georg, Martin Semsch, Leonardo Felix Borim
Abstract Residual brake torque (RBT) is generated in disc brakes as a result of contact between brake disc and brake pads when the braking pressure is not applied. Among the negative implications of RBT are, notably, dispensable additional fuel consumption as well as increased pad (taper) wear. Several properties of the brake system have a direct influence on the level of residual torque [1]. A major effect is connected to the caliper properties determining the clearance gap. This is characterized by the default air gap between pads and disc and its distribution regarding vehicle inner and outer sides (piston and fist sides for floating type calipers). Initial air gap is mainly influenced by the sealing grove design (between piston and housing, where the sealing ring is positioned). The retraction of the piston due to the sealing ring, also called rollback, mainly depends on the load case (e.g. applied pressure and temperature).
2017-05-24
Technical Paper
2017-36-0015
Alexis Klauber Chaia Kléperon, Robson Demétrius Araújo Abreu, Rômulo Morais Bitencourt, Francis José Marochi Almeida
Abstract The vibroacoustic comfort sense inside vehicles is a topic of major concern in current automotive industry. Moreover, the increase in demand of users and the competition in the automotive sector lead automakers to invest in developing more comfortable vehicles. Thus, even noises in specific usage scenarios and short time is claimed. This paper raises the cause and proposes solutions to a noise from the brake system known as "Moan Noise". This noise happens under specific conditions of use, but is easily identified by the user. Moreover, it is a random phenomenon and difficult to characterize. Thus, this study shows a methodology to survey the phenomenon under study and validation of proposals for improvement through operational techniques and experimental modal analysis.
2017-05-24
Technical Paper
2017-36-0011
J. Ocampo, S. Jelic, J. Han
Abstract Thermal performance of a brake system is one of the key attributes in a new vehicle development process. Adequate brake cooling characteristics are part of the vehicle performance and safety requirements. The design of a new brake system, however, can be a complex task from a thermal engineering perspective, particularly because of complex interactions between the brake component and the rest of the vehicle. Frequently, the vehicle integration issues are the most serious challenges for brake engineers. There are considerations on how much heat should be dissipated from a single and/or consecutive braking events vs. how much cooling can be provided to the brake corner. Design issues such as where to direct the cooling air to how much flexibility is allowed while complying with other requirements from the studio and aero teams. For a brake engineer, the priority is to maximize cooling to the brake corner and prevent system failure.
CURRENT
2017-05-18
Standard
J3052_201705
This recommended practice provides a method, test set-up, and test conditions for brake hydraulic component flow rate measurement for high differential pressure (>5 bar) flow conditions. It is intended for hydraulic brake components which affect the brake fluid flow characteristics in a hydraulic brake circuit, that are part of a circuit for which the flow characteristics are important to system operation, and that are exposed to high operating pressure differentials (in the 5 to 100 bar range). Typical applications may include measurement of flow through chassis controls valve bodies, orifices in the brake system such as in flow bolts, junction blocks, and master cylinders, and through brake pipe configurations.
2017-05-16
WIP Standard
J1842
This SAE Recommended Practice is intended for hubs and spoke wheels used on Class 6, 7, and 8 truck/truck-tractor non-powered front axles, powered and non-powered rear axles and trailer axles, for which bearing setting is manually adjusted. Assemblies using spacers to control bearing preload and endplay may differ in geometry and bearing componentry.
2017-05-15
Article
Lightweighting, direct fuel injection and turbocharging have been vital to achieving significant improvements in performance and efficiency; however, mechanical solutions alone cannot solve these challenges, says Dana CTO George Constand. Integrated electronics and software solutions are key for overall system design strategies.
2017-05-09
Article
Equipped with Continental sensor technology, the height of ContiTech’s air springs can now be adjusted electronically, the internal pressure monitored and the internal temperature measured.
2017-05-09
WIP Standard
J1953
This SAE Recommended Practice shall cover mechanical- readjust stroke indicators for actuators with visible exposed pushrods and electrical-readjust stroke indicators for all air-brake actuators. This device shall indicate the foundation brake(s) may require adjustment or service when inspected per vehicle manufacturer's procedures. A measurement shall be made to determine actual stroke measurement for any system not factory calibrated. Stroke indication accuracy of an air-brake actuator can be assured only when all of its components are supplied by the original brake actuator manufacturer.
2017-05-03
Article
Volvo Buses has started the global launch of its latest chassis powered by the 8-L Volvo engine. The Volvo B8R and B8RLE replace the top-selling Volvo B7R and B7RLE, which saw a production run exceeding 40,000 units and sales in 65 countries.
2017-05-03
WIP Standard
AIR6952
The pupose of this SAE AIR is to provide guidelines for sizing stored energy systems in use in emergency braking systems, in light of their intended purpose and applicable certification regulations.
2017-05-03
WIP Standard
J2383
This SAE Recommended Practice establishes uniform Installation Parameters for desiccant Air Dryers for vehicles with compressed air systems.
2017-05-02
WIP Standard
AIR6168A
This SAE Aerospace Information Report (AIR) discusses past and present approaches for monitoring the landing gear structure and shock absorber, methods for transient overload detection, techniques for measuring the forces seen by the landing gear structure, and methods for determining the fatigue state of the landing gear structure. This AIR covers the landing gear structure and shock absorber. It does not include the landing gear systems or landing gear wheels, tires and brakes. Landing gear tire condition and pressure monitoring are detailed in AIR4830 and ARP6137, respectively.
2017-05-02
WIP Standard
ARP6951
Identify best practices to reduce tire damage during storage, shipping and handling.
2017-05-02
WIP Standard
J2255
This SAE Recommended Practice provides instructions and test procedures for measuring air consumption of air braked vehicles equipped with Antilock Brake Systems (ABS) used on highways. This document provides a method to determine the air consumption of highway vehicles when the brake system must maintain performance when the service brake control is applied for long periods of time.
2017-05-02
WIP Standard
J2384
This SAE Recommended Practice establishes uniform Test Procedures for desiccant Air Dryers used in vehicles with compressed air systems per SAE J2383. Continuous flow desiccant Air Dryers are excluded from the scope of this document.
2017-05-01
Article
With smaller exterior dimensions, 200-lb less mass and unique chassis tuning, the 2017 Rogue Sport crossover utility is called Qashqai in other markets.
CURRENT
2017-04-27
Standard
J2743_201704
This SAE Recommended Practice is intended to describe a procedure for rating the size of single-stage reciprocating air compressors. It describes the conditions that can be used for testing and it defines a standardized rating expressed in SLPM (SCFM).
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