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This paper summarizes the methodology and findings of an investigation to determine friction coefficients between typical loads and trailer deck materials in static, sinusoidal, and field measured random vibration environments. To conduct the tests in a controlled laboratory environment, a special sled-deck fixture was designed. Provisions were made to allow a change in sled-deck contact materials and to vary the load on the sled. For dynamic testing, the deck was subjected to sinusoidal and field based random signals obtained from tractor-trailer traversing paved and gravel roads. The results reveal that under vertical vibration, these friction coefficients can be as low as 25% of their corresponding static values. The random vibration tests revealed that friction coefficients can fall below 75% of the mean value for up to 35% of the total test duration. Thus, loads that rely on static friction for security may be highly prone to load shifts in a dynamic environment.

It is well known that the excessive levels of vibration in heavy vehicles negatively affect driver comfortability, cargo safety and road condition. The current challenge in the field of suspension design for heavy vehicles is to optimize the suspension dynamic parameters to improve such requirements. Almost all of the previous work in this field is based on applying the mathematical optimization considering active or passive suspension systems to obtain the optimal dynamic parameters. In this work a new passive suspension systems for heavy trucks is suggested and compared with the conventional passive suspension systems. The new systems rely on transferring the vertical motion, (vibration), into horizontal motion through a bell-crank mechanism to be taken by a horizontal passive suspension system. The system dynamic parameters like body acceleration, suspension travel and dynamic tire load are calculated assuming random excitation due to road irregularities.

Today, active dynamic control systems for commercial vehicles, offering improved safety, are frequently discussed. Yaw stabilising systems are based on theories from passenger car implementation, yet roll stabilisation - probably introduced in the near future - requires increased knowledge of rollover mechanics. Static analysis, providing steady state rollover threshold (SSRT), is the most common approach. Nevertheless in a rolling vehicle, kinetic energy is always present, deteriorating roll stability, invalidating the analysis. A simple method determining the dynamic rollover threshold (DRT) is therefore introduces in this paper. DRT is the worst case measure of roll instability: the conditions are necessary but not sufficient for rollover.

This SAE Recommended Practice applies to all commercial, self-propelled, or towed motor vehicles which transport property or passengers in interstate commerce in which the gross vehicle weight rating or gross combination weight rating exceeds 4550 kg (10 000 lb).

A modern product creation process has been applied to a commercial vehicle development project at DaimlerChrysler do Brasil S.A. Key elements are a structured development process in defined stages divided by gateways, which are surpassed only upon successful completion of exit criteria. The process is based on the product development process GPO of DaimlerChrysler's European truck business unit.

The increase of active safety will demand more and more electronic intelligence, if a drastic optimization of conventional systems is not possible any more. Starting from today's mechatronic systems, the trend leads via tomorrow's smart electronic systems to the future electronic networking of all intelligent vehicle systems. The paper describes the present status of these systems in Europe and the possibilities of increasing the active safety by using electronic intelligence.

The development of electronic intelligence and the continually increasing intensive knowledge of driving dynamics make it possible nowadays to conceive intelligent vehicle systems and to make such systems available for series production, which are capable of substantially enhancing the active safety of commercial vehicles. Through the implementation of advanced subsystems, which can be integrated as software packages into the basic electronic braking system, it will be possible to expand the possibilities of introducing assistance systems, which are capable of both, helping and relieving the driver from stress in critical situations. The driver will be relieved of all duties which could divert his attention or cause severe stress. As a consequence, the active safety of commercial vehicles will be considerably increased.

The objective of this paper is to present the update procedures and the future tendencies for the diagnosis projects in commercial vehicles, specially buses and trucks. The constant increase in the number of components and electronic systems in commercial vehicles demands that the subject “Diagnosis” be treated and previously defined, while the vehicle is in the project phase. The final goal of this thought is to provide to the vehicle the best possible acting of all the electronics systems placed in vehicle, and, as a consequence, the best running of the On-Board and Off-Board diagnosis systems which should assist the customer needs directly. The tendency is to project the vehicles of the same brand in the same conceptual line facilitating the assembly work in production line and the after sales support.

The present work aims at to approach considerations of trucks suspension design. The proposal of the work consists of discussing the aspects related to the acting of the suspension and of factors that interact with the system through representative models of the dynamic behaviour of the vehicle ride when operating in total load and/or empty conditions. The importance of this work is to revise some procedures of suspension study in the sense of adapting them to the Brazilian reality, tends in view the importance of the design characterisation and adaptation to the typical roads of Brazil.

Windup behavior is particularly dangerous in a commercial vehicle, since it can generate undesired lateral movements. Methods previously applied to determine this behavior were not cost nor time efficient. A new proposed method that applies CAD/CAE tools was presented in a previous paper, but that work still relied on a correction factor that is based on a experimental test. Therefore, the present study is geared at eliminating these experimental tests, through the use of a suitable mathematical model and nonlinear analysis.

Sport Activity Vehicle (SAV) share a growing market of an entirely new class of vehicles. Outstanding comfort in traditional on-road and also off-road terrain combined with leading edge technology are basic features of this concept. But in addition to that, the SAV has to offer the same overall safety features, expected by e.g. a luxury-segment sedan. A way to ensure the BMW X5 becoming one of the safest cars was the consequent use of simulation techniques in passive safety development. This paper deals with introduction of a CAE driven development process for passive safety in the BMW X5 project, focusing on examples in front and side impact.

Lightpipe design According to Breault Research Organization, any off-highway instrument or control that needs illumination is a candidate for a lightpipe to take light from where it is generated to where it is needed. The biodiesel choice Experts from the Natural Biodiesel Board believe it is time to consider alternatives to the current fuel structure. One solution to rising fuel prices is the pursuit of biodiesel fuels. Understanding machining difficulties in gray iron Bosch Braking Systems' engineers look more closely than usual at iron brake rotor samples to give new insights into critical characteristics of the material. Caterpillar mining for customers With commodity prices low, Caterpillar wants to make mining as productive an enterprise as possible for customers.

HID for both beams Automotive Lighting engineers have developed HID lighting for high-beam as well as low-beam functions. High-flux LED light sources Hella's advances in LED design provide new options for signal lights and styling variations for indirect lighting. Top 10 technologies for 2000 Readers have selected the most interesting technology stories appearing in Automotive Engineering International during the past year. The rankings are based on reader responses from feature articles and shorter technology items. Some of the stories appear here in shortened form. Synthetic diesel engine oil Researchers at ExxonMobil have developed an advanced lubricant for heavy-duty diesel engines. Disel Emission Control--Sulfur Effects The objective of this government-industry program is to determine the impact of fuel sulfur levels on emissions-control systems of diesel engines.

Increased demand for gears to transmit more power through smaller, lighter, quieter, and more reliable packages that must operate over a wide range of service conditions, has made the design and manufacture of gears much more complex. Gears manufactured from certain steels are found to meet these demands, and become especially effective when heat treated and finish machined for high geometric accuracy. However, distortion of the gear after heat treatment offers the gear engineer a challenging opportunity not only in ensuring a high quality product but also in controlling manufacturing costs. Heat Treatment of Gears is designed to provide the gear design engineer with a better understanding of heat treatment and its effects on gear quality and performance, especially as these considerations are critical to ensuring that the gears perform satisfactorily under anticipated service conditions.

Designed to support the need of engineering, management, and other professionals for information on titanium by providing an overview of the major topics, Titanium: A Technical Guide provides a concise summary of the most useful information required to understanding titanium and its alloys. The author provides a review of the significant features of the metallurgy and application of titanium and its alloys. All technical aspects of the use of titanium are covered, with sufficient metals property data for most users.

Because of the intense focus on fuel economy and fuel emission standards, it has become imperative to optimize vehicle drivetrains. In light of this, component efficiencies have become an important factor in the drivetrain decision-making process. It has therefore become necessary to develop a universal standard to judge transmission efficiency. This SAE Recommended Practice specifies a test procedure which maps torque transmittal efficiency and parasitic losses for manual transmissions. The application of this document is intended for manual transmissions used in light (class 4) through heavy truck applications with both simple and compound ratio structures. This document is separated into two parts. The first compares input and output torque throughout a specified input speed range in order to determine the overall transmission efficiency. This test is used to evaluate all forward gears; testing in reverse is optional.

Getting the aero advantage Team Rahal has come up with several innovative ways of integrating and implementing Fluent Inc.'s computational fluid dynamics softwarae into its engineering process. Jordan Grand Prix benefits from 3-D design This motorsports team's transition from 2-D design to 3-D digital modeling using SDRC's I-DEAS software has resulted in shorter lead times and improved part fit. The 2002 Explorer/Mountaineer Ford engineers further improve ride, handling, and safety while increasing the vehicles' power. Cadillac's re-engineered Escalade The 2002 model has a host of new, advanced features including "Northstar-inspired" powertrains, StabiliTrak stability control, and a Road Sensing Suspension system. Explorer Sport Trac breaks new ground Ford says its 2001 Explorer Sport Trac, based on the 2001 Explorer four-door, was engineered for improved ride and handling, and is the first traditional SUV with an open cargo area.

Since aluminum alloys offer an excellent combination of light weight, high-strength, great corrosion resistance and reasonable cost, they have become one of the most commonly used metal groups today. This electronic publication addresses the need for basic information on aluminum alloys and their tempers. The author provides the reader with an understanding of the advantages and limitations of aluminum alloys and temper combinations in terms of the relationship of their composition, process history, and microstructure to service requirements. The temper designation of an aluminum alloy provides the user with background information as to how the alloy has been produced in order to obtain specific and desired properties and characteristics.

Three joint Government/Industry program have been reviewed to evaluate the effect of fuel properties and source on exhaust emissions from three post 1994 model year heavy-duty diesel engines, a single cylinder research engine and a prototype multicylinder engine designed to meet the 2004 model year oxides of nitrogen limit. The three post 1994 engines tested (at Environment Canada's facility) were a Detroit Diesel Series 50, a Caterpillar 3406E and a Cummins N14. Exhaust emissions of NOx, PM, CO, HC, and CO2 were measured using the “hot” US EPA Heavy-duty Transient Test Procedure. The single cylinder Ricardo Proteus research engine (run at the National Research Council of Canada) and the multicylinder Caterpillar 3176 prototype engine (run at the Southwest Research Institute) were tested using the AVL 8 mode test cycle. Fifteen fuels were tested in total: three “reference” Commercial Low Sulphur diesel fuels and twelve experimental fuels.

CFD simulations have been conducted to investigate the combustion in a direct-inject (DI) diesel engine using the Ricardo engine CFD program VECTIS and the Ricardo Two-Zone Flamelet (RTZF) combustion model. The simulation program covers full load and part load operating conditions, each including 6 to 7 cases forming an injection timing swing. CFD simulation results are compared against engine tests for the in-cylinder pressures and NOx emissions. The comparison shows that the RTZF combustion model performs well in all cases studied with no tuning of model coefficients necessary. The detailed time history of spray, fuel distribution and flame development obtained from the CFD simulation provides useful information towards gaining a better understanding of the features of combustion in DI diesel engines.