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Technical Paper

Brake Squeal Generation

1999-05-17
1999-01-1735
Brake squeal, which is a noise, occurs in the range of frequencies 1 to 16 kHz is an important task for research to develop the vehicle passenger comfort. This phenomena has been studied many years theoretically and experimentally to gain better performance of brake and eliminating the squeal problem. The work presented here is focusing on the effect of the brake pad manufacturing on the generation of brake squeal. A simple proposed three-degree of freedom model has been used in the study to simulate the brake components (pad, caliper, and disc). The brake squeal and frequency response of brake pad has been measured at different working conditions (pressure, sliding speed, and brake pad type). A comparison between the theoretical and experimental work has been made and a good agreement was found between the theoretical prediction of the brake assembly natural frequency and the experimental measurement.
Technical Paper

A Study in Rollover Prevention Using Anti-Rollover Braking

2000-05-01
2000-01-1642
A single vehicle on-road rollover accident of a small van is used to examine the effectiveness of the Anti-Rollover Braking System (ARB). The circumstances of the accident are reviewed, and how the accident was modeled using ADAMS. ARB is then added to the vehicle model to examine what would happen if ARB had been on the vehicle. Two cases are examined. One case uses the same steering as in the accident, and one case uses the same path as the accident. In both of these cases, ARB would have prevented the vehicle from rolling over.
Technical Paper

A New Sliding Mode Controller for Four-Wheel Anti-Lock Braking System (ABS)

2000-05-01
2000-01-1639
This paper presents a new method for finding slip control law of Anti-lock Braking System (ABS), based on sliding mode control method . A four wheel car model with seven degrees of freedom is considered. Slip of each wheel is controlled separately so that it remains in the desired range for every kind of road condition, and by tuning desired slip undesired yaw on miu-split surfaces is prevented.
Technical Paper

Design of Front Wheel Active Steering for Improved Vehicle Handling and Stability

2000-05-15
2000-01-1619
Active steering has received lot of attention in the recent years because of the development of vehicle stability control systems and intelligent vehicle highway systems. Active steering systems allow for correction of the steer angle to achieve the desired vehicle yaw gain. The proposed system can be easily integrated with the vehicle stability control systems that use braking to control the vehicle yaw gain. The paper describes the concept of front wheel active steering system and the design techniques involved in order to achieve the desired performance from the system. The design techniques demonstrated in the paper do not address noise (gear rattles, motor noise, gear whine etc), electromagnetic compatibility and thermal issues related to DC motor and digital controller.
Technical Paper

Simulation Based ABS Algorithm Development

1999-11-15
1999-01-3714
This paper discusses the needs for utilizing pure simulation based studies in the algorithm development process for cost reduction in today's competitive business environment. Continuous improvement to any algorithm is essential for sustained existence and any modification to the logic needs to be verified to work for every scenario from feasibility and robustness viewpoints. A Pareto analysis performed on the development cycle of an ABS algorithm identifies these high cycles clearly. In this paper, it is proposed that significant cycle time reduction can be achieved with the aid of pure desktop simulations during the development phases. Additionally, the feasibility of using such simulations is demonstrated through the ABS algorithm simulation model that is developed at AlliedSignal Truck Brake Systems.
Technical Paper

Verification of Heavy Truck EBS and ABS Using MatrixX Hardware in the Loop Tools

1999-11-15
1999-01-3713
The development of advanced ABS, EBS, and vehicle dynamics control systems requires significant resources and testing. Even in the most controlled environment, on-track vehicle tests are not repeatable. A heavy vehicle model combined with pneumatic brake hardware connected to actual brake system controllers creates a powerful engineering tool. This tool is useful for control system development, electro-mechanical actuator development, and brake system development. An existing heavy vehicle model is modified to interact with the realtime simulation hardware and the pneumatic brake system hardware. Data from several hardware in the loop simulations are presented.
Technical Paper

Improved Heavy Vehicle Wheel Dynamics Model Using MATLAB/SIMULINK

1999-11-15
1999-01-3707
The accuracy of existing rotational wheel dynamics models has been found to be insufficient for heavy vehicle Antilock Braking System (ABS) and Electropneumatic Braking System (EBS) simulation, specifically when wheelspeeds are at or near zero but the vehicle speed is not. Control strategies specific to ABS and EBS, the low frequency response of pneumatic actuation, and the practice of using fewer modulators than braked wheels require that a vehicle model be able to handle lockedwheel scenarios accurately. Commercially available models have been found unsatisfactory in this regard, and technical literature has not been found to address this issue.
Technical Paper

Advanced Compressor and Air Dryer Charging Systems

1999-11-15
1999-01-3772
This paper presents the advantages and disadvantages of the traditional charging and storage systems of a heavy duty air braked vehicle, versus an advanced air charging system. Traditionally separate components are installed on a heavy duty vehicle to perform the air drying and air distribution functions. Current air systems charge the primary and secondary reservoirs through a supply reservoir. As a result, current systems require more space, have more potential leak points and are more labor intensive to install. Charging and storage system Failure Mode and Effects Analysis (FMEA) will discuss the various alternate strategies to simplify and enhance the air charging system. Furthermore, a look at future enhancements to charging systems is considered.
Technical Paper

Electronic Compressor and Air Dryer Control

1999-11-15
1999-01-3771
The paper details opportunities for electronic control of the pneumatic charging system of an air braked vehicle. Electronic control of the charging and drying functions can result in increased fuel efficiency and improved air quality. Control functions can be used to identify and warn of in-service issues, provide prioritized system charging for faster drive-away, and signal required preventative maintenance. The first portion of the paper describes current industry practice, as well as common issues that can result from those practices. This is followed by presentation of areas of improvement, where specialized control features result in energy savings, air quality increases and maintenance/downtime savings. This portion will focus on adaptive control of components used today, and will briefly discuss opportunities for the next generation of charging system devices. The final section of the paper presents the control logic and vehicle interface allowing for system integration.
Technical Paper

Analysis of Elastic Distortions of a Piston Ring in the Reciprocating Air Brake Compressor Due to the Installation Stresses

1999-11-15
1999-01-3770
The objective of this paper is to present the results of an investigation of elastic distortions of split piston rings that are used in lubricated and non-lubricated air brake compressors. Concepts of advanced stress analysis and Finite Element Analysis (FEA) have been employed in this study. The analysis of elastic distortions (twist) of piston rings due to the installation stresses has been quite poorly documented in the technical literature. As a result, unjustifiable engineering assumptions are some time made which result in misleading design solutions. This paper demonstrates analytically and with the support of FEA the mechanical/geometrical parameters of a split ring which affect the twist of the ring during the installation in the cylinder bore, and the calculated magnitude of this twist along the ring circumference.
Technical Paper

Analytical Solution of Piston Ring Pack Lubrication for Truck Air Brake Compressor

1999-11-15
1999-01-3769
This paper presents an analytical solution of piston ring pack lubrication for two-cylinder truck air brake compressor. A system of nonlinear equations with seven variables was developed to describe lubrication phenomena of the piston ring pack for both fully flooded and starvation conditions. The full mass conservation boundary conditions defined by JFO ([14],[15]) theory were employed for complete description of the cavitation algorithm with enclosed and open cavitation patterns. Impact of the piston ring design parameters such as offset, crown height, and tension on the oil transport, lubrication conditions and friction losses of the compressor were discussed in details.
Technical Paper

New Traction-Optimized Front Axle Limited-Slip Differential for AWD All-Terrain-Vehicle

2000-03-06
2000-01-1155
An advancement in All-Terrain-Vehicle (ATV) traction control has entered the market place with the debut of the 1999 Bombardier Traxter. The basis for this is the progressive front axle limited-slip differential. The Visco Lok‚ differential provides a speed-sensing progressive traction-optimized characteristic for maximum off-road performance. This paper includes an overview of the vehicle driveline system, functional characteristics of the differential, and torque transfer requirements.
Technical Paper

Molding Advancements for Phenolic Automotive Components

2000-03-06
2000-01-1164
This paper will explore molding systems that are improving phenolic composite molding specifically for the automotive component market. Topics will address processing advancements including innovative injection molding systems such as HTM™ (High Temperature Molding), RIC™ (Runnerless Injection Compression), utilization of “Live Sprues” in injection tools, and general automation of the processes which produce these components. Competition within the industry is becoming very intense and the utilization of these processes along with the advances in computer technologies will help to keep profits and reduce manufacturing costs. Molded Components that will be addressed in this paper are: Solenoid Cap - Standard compression molding vs. Automated compression molding, vs.
Technical Paper

Sources of Hydrocarbon Emissions from a Direct Injection Stratified Charge Spark Ignition Engine

2000-06-19
2000-01-1906
The purpose of this paper is to assess the influence of fuel properties on cycle-resolved exhaust hydrocarbons and investigate the sources of hydrocarbon (HC) emissions in a direct injection stratified charge (DISC) SI engine. The tested engine is a single cylinder version of a commercial DISC engine that uses a wall guided combustion system. The HC emissions were analyzed using both a fast flame ionization detector (Fast FID) and conventional emission measurement equipment. Three fuels were compared in the study: iso-Pentane, iso-Octane and a gasoline of Japanese specification. The measurements were conducted at part-load, where the combustion is in stratified mode. The start of injection (SOI) was altered in relation to the series calibration to vary the mixture preparation time, the time from SOI to ignition. The ignition timing was set at maximum brake torque (MBT) for each test.
Technical Paper

Characterization of Emissions from Hybrid-Electric and Conventional Transit Buses

2000-06-19
2000-01-2011
Hybrid-electric transit buses offer benefits over conventional transit buses of comparable capacity. These benefits include reduced fuel consumption, reduced emissions and the utilization of smaller engines. Factors allowing for these benefits are the use of regenerative braking and reductions in engine transient operation through sophisticated power management systems. However, characterization of emissions from these buses represents new territory: the whole vehicle must be tested to estimate real world tailpipe emissions levels and fuel economy. The West Virginia University Transportable Heavy Duty Emissions Testing Laboratories were used to characterize emissions from diesel hybrid-electric powered as well as diesel and natural gas powered transit buses in Boston, MA and New York City.
Technical Paper

Variable Effort Steering for Vehicle Stability Enhancement Using an Electric Power Steering System

2000-03-06
2000-01-0817
This paper investigates a method for improving vehicle stability by incorporating feedback from a yaw rate sensor into an electric power steering system. Presently, vehicle stability enhancement techniques are an extension of antilock braking systems in aiding the driver during vehicle maneuvers. One of the contributors to loss of vehicle control is the reduction in tactile feedback from the steering handwheel when driving on wet or icy pavement. This paper presents research indicating that the use yaw rate feedback improves vehicle stability by increasing the amount of tactile feedback when driving under adverse road conditions.
Technical Paper

OSEKtime: A Dependable Real-Time Fault-Tolerant Operating System and Communication Layer as an Enabling Technology for By-Wire Applications

2000-03-06
2000-01-1051
The new generation of drive-by-wire systems currently under development has demanding requirements on the electronic architecture. Functions such as brake-by-wire or steer-by-wire require continued operation even in the presence of component failures. The electronic architecture must therefore provide fault-tolerance and real-time response. This in turn requires the operating system and the communication layer to be predictable, dependable and composable. It is well known that this properties are best supported by a time-triggered approach. A consortium consisting of German and French car manufacturers and suppliers, which aims at becoming a working group within the OSEK/VDX initiative, the OSEKtime consortium, is currently defining a specification for a time-triggered operating system and a fault-tolerant communication layer.1 The operating system and the communication layer are based on applicable interfaces of the OSEK/VDX standard.
Technical Paper

Development of Indigenous Automatic Load Sensing Valve

2001-01-10
2001-26-0036
Braking of automotive vehicles is facilitated by the adhesion between the tyre and the ground. Braking forces generated at the wheels of a vehicle have to be appropriately matched to this adhesion. Load Sensing Valve(LSV) is one of the devices used to achieve this objective. An Automatic Load Sensing Valve (ALSV) is developed which can be used in the Air Brake system of commercial vehicles. Considering the typical Indian operating conditions (compared to European and American environment) for commercial vehicles, it was necessary to collect ‘customer voices’ to finalise minimum as well as desirable product features for the valve. Quality Function Deployment (QFD) was used to convert these customer voices into design specifications. Benchmarking of several similar products was done. This has resulted in a product which is having not only the minimum features found in a similar contemporary international product but also meets the typical requirements of Indian customers.
Technical Paper

Design Issues of the Switched Reluctance Motor Drive for Propulsion and Regenerative Braking in EV and HEV

2001-08-20
2001-01-2526
There is a growing interest in electric and hybrid electric vehicles (EV and HEV) due to their high efficiency and low emission. In EV and HEV, the characteristic of the traction motor is essential for the performance and efficiency of the EV and HEV. In this paper, the advantages of the extended constant power range characteristic of the traction motor for both propulsion and regenerative braking are analyzed. Simulation results are presented to verify the conclusions. Due to its several inherent advantages, especially its capability of having an extended constant power range, Switched Reluctance Motor (SRM) is proposed as the candidate of the traction motor in EV and HEV. The design methodology of SRM for achieving an extended constant power range and the control strategy of SRM for regenerative braking in EV and HEV are presented.
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