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On current competitive scenario for road load transportation in Brazilian market, the operational costs should be reduced as much as possible. The suspension system commonly used on road commercial trucks is based on leaf spring use and Hotchkiss concept for axle locating devices. The use of leaf springs without bolt attachment eyelets are still common for rear suspension systems. When using the leaf spring with direct contact to the brackets, wear plates are placed between them to work as wear elements due to the friction between the parts. The friction will cause wear on the parts, and the wear plate is designed to suffer the damages of this friction instead of the leaf spring, being the cheapest element and can be easily replaced. When the system works on a severe contamination environment with high levels of grit and dirt, the degradation of the parts are accelerated.

The brake pedal is the brake system component that the driver fundamentally has contact and through its action wait the response of the whole system. Each OEM defines during vehicle conceptualization the behavior of brake pedal that characterizes the pedal feel that in general reflects not only the characteristic from that vehicle but also from the entire brand. Technically, the term known as Pedal Feel means the relation between the force applied on the pedal, the pedal travel and the deceleration achieved by the vehicle. Such relation curves are also analyzed in conjunction with objective analysis sheets where the vehicle brake behavior is analyzed in test track considering different deceleration conditions, force and pedal travel. On technical literature, it is possible to find some data and studies considering the hydraulic brakes behavior.

The stabilizer bar attachments problem can not be simply analyzed by using linear FEA methodology. The large deformation in the bushing, the elastic-plastic material property in the bushing retainer bracket, and the contact between different parts all add complexity to the problem and result in the need for an analysis method using a non-linear code, such as ABAQUS. The material properties of the bushing were experimentally determined and applied to the CAE model. It was found that using strains to estimate the fatigue life was more accurate and reliable than using stress. Many modeling techniques used in this analysis were able to improve analysis efficiency.

Some communication buses are too powerful and expensive for simple digital on/off operations such as activating lights, wipers, windows, etc. For these applications the LIN bus is currently the most promising communication protocol across the world's automotive industry. This paper addresses a study using LIN (Local Interconnect Network) for Ford South America vehicles. This will propose a new electrical architecture designed with LIN network, which will be replacing the conventional rear and front lights cables in Trucks, where other higher protocols, such as CAN, are not cost effective. LIN is a new low cost serial communication system intended to be used for distributed electronic system that will allow gaining further quality enhancement and cost reduction on cables, connectors and switches.

Considering that the most part of commercial vehicles are equipped with air brakes it is very important assure specific technical requirements for air brake system and its components. In addition, the effects of brake system failure are more critical for commercial vehicles which require more attention on their requirements details. Historically, the development of air brakes technology started on North America and Europe and consequently two strong and distinct resolutions were structured: FMVSS 121 and ECE R.13, respectively. For passenger cars were developed the ECER.13H to harmonize North American and European resolutions. However, for commercial vehicles regional applications, culture and implementation time must be considered. These commercial vehicles peculiarities must be understood and their specific requirements harmonized to attend the global marketing growth.

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.

The development costs that new design requires are subject to everyday discussions and saving opportunities are mandatory. Using CAE to predict design changes can avoid excessive costs with prototypes parts, considering the high reliability those current mathematical models can provide. This paper presents the methodology used during the development of a parabolic leaf spring for the rear suspension of a commercial truck, considering mainly the parabolic profiles and stress distribution on the leaves, calculated using CAE software (ANSYS) and experimental tests to measure the actual stress on each leaf, certifying the correlation between computational calculations and real stress on the parts during bench and vehicle evaluations.

In order to optimize the development of bolted joints used to components attachments in the Sidemember of commercial vehicles, the joints development has become relevant to better definition of the fasteners size, eliminating overweight and avoiding under or super-sized. This paper presents a development sequential approach of bolted joints applied on commercial vehicles ensuring the correct specifications usage of the fasteners and the joint to keep their clamp force. The evaluations were conducted based on theoretical and practical aspects applied on products and in the definition of all elements contained in a joint. The calculation methodology was developed based on standardized bolts and forces generated through the reactions of the components required for each vehicle family.

Hydroformed truck frame side rails from circular tubes are studied for gage variations and pre-strain to be used in crash FEA modeling practice. This study provides simplified models that achieve feasible correlation with actual tests. Meanwhile, from plasticity theory we derive a forming equation in conjunction with forming limit diagrams to estimate material properties for hydroformed rails.

Recent surveys of customer satisfaction with full size pickup trucks have raised the standards for passenger comfort and refinement of such vehicles. Customers for this type of vehicle demand performance levels for attributes such as NVH, ride, and handling that previously belonged to luxury passenger cars. Along with the increased passenger comfort, full size pickup trucks must retain a tough image and be as durable as the previous generation trucks. The challenge is to design for NVH performance that can match and surpass many well behaved and “good” NVH passenger cars without any compromise in durability performance. One aspect of “good” NVH is a steering wheel which is free from vibration. As part of the development of a new design for a full sized pick up truck, an NVH subjective rating of 8-9 (10 is maximum) was targeted for the design of steering column/ instrument panel assembly.

The growing competition of the automotive market makes more and more necessary the reduction of development time and consequently, the increase of the capacity to quickly respond to the launching of the competitors. One of the most costly phases on the vehicle development process is the field durability test, both in function of the number of prototypes employed and the time needed to its execution. More and more diffused, the fatigue life prediction methods have played an important part in the durability analysis via CAE. Nevertheless, in order they can be reliable and really being able to reduce the development time and cost, they need to be provided with load cases that can accurately represent the field durability tests. This work presents a CAE approach used for light trucks in order to get a reasonable understanding of component durability behavior due to payload increase. In general, road load data is not available for a new payload condition.

Recent accomplishments, made possible by advances in manufacturing and material technology, have led to the development of a one-piece stamped I-Beam axle with ball joints as a replacemet to the forged axle with king pin design. The new stamped I-Beam axle brings with it a number of improvements to Ford's Twin I-Beam suspension system. This paper describes the objectives, improvements, evolution of the design, testing, and the manufacturing process for this latest suspension system improvement on Ford light trucks.

This paper discusses the possible impact of the FM tape recorder and servo-hydraulic actuators on the testing of automotive structures. The use of tape recorders and automatic data reduction systems will permit more accurate definition of service conditions and properly “set-the-stage” for laboratory testing. Servo-hydraulic strokers should encourage better laboratory simulation because of their great flexibility. Test set-up time is reduced, fixtures can be simplified and load control is more precise. Simultaneous multiple inputs can be controlled as to amplitude and phase relationships.

This paper describes the design and build of an experimental super transport truck for high-speed, long distance freight hauling on the interstate highway system of the 1970's. The tractor, powered by a 600-hp gas turbine engine, pulls two 40-foot tandem axle trailers at a G.C.W. of 170,000 lbs. Details of the turbine engine development are covered in SAE paper, No. 991B. One of the features of the super transport truck is the cab, which is designed for long-distance, non-stop, two-man operation. It is provided with sleeping accommodations, washroom conveniences, food facilities, and a complete heating and air-conditioning system. The 13-foot high cab roof is flush with the top of the trailers, providing a substantial aerodynamic advantage. Other features and components of the truck are described, and observations made during the 5500-mile national tour are discussed.

Integrating microcomputer-based components and high technology displays to the heavy-duty truck instrument panel is an evolutionary step in panel development. The application and technology, based on automotive experience, is proven and the initially higher cost of more sophisticated instrumentation will be offset by capabilities offering a return on investment not possible even with the most modern electromechanical instrumentation.

Ford's continued effort to improve fuel economy in automotive applications has emphasized the need for lightweight components that retain all the toughness associated with Ford truck vehicle characteristics. The application of an impact extrusion process to wheel design and manufacture, for Ford Aerostar, provides strength, performance and style more efficiently than other traditional processes. It results in a valuable 33% weight saving over comparable HSLA steel wheels, and provides the customer with uncompromised value. The Ford Aerostar Impact Extruded Aluminum Wheel was designed to be of one-piece construction, manufactured from a less than 1″ thick aluminum wafer-shaped blank. The process permits manufacture in half the steps of a conventional stamped steel wheel, and eliminates extensive machining required with forged or cast aluminum wheels.

Do older light trucks, often with second (and subsequent) owners, present a higher risk to either their own occupants or to other road users? And is the safety record for newer trucks better or worse than the record for their older counterparts? To answer these questions, fatalities in crashes involving at least one light truck were examined using the Fatal Analysis Reporting System (FARS). Fatality rates for both occupants of the light truck and for other road users (occupants of other motor vehicles, pedestrians, etc.) in these crashes were computed, based both on the number of registered vehicles and on the vehicle miles of travel. Two trends in these fatality rates are observed. First, as light trucks age, a consistent decline is found in risk both to their own occupants and to other road users. Second, a distinct decrease is found in road user risk for newer light trucks compared to older light trucks when they were new, both for their own occupants and for other road users.

Analysis of road accidents has shown that an important portion of fatal crashes involving Commercial Vehicles are caused by rollovers. ESC systems in Commercial Vehicles can reduce rollovers, severe understeer or oversteer conditions and minimize occurrences of jackknifing events. Several studies have estimated that this positive effect of ESC on road safety is substantial. In Europe, Electronic Stability Control (ESC) is expected to prevent by far the most fatalities and injuries: about 3,000 fatalities (-14%), and about 50,000 injuries (-6%) per year. In Europe, Electronic Stability Control Systems is mandatory for all vehicles (since Nov. 1st, 2011 for new types of vehicle and Nov. 1st, 2014 for all new vehicles), including Commercial Vehicles, Buses, Trucks and Trailers.

The brake pedal is the brake system component that the driver fundamentally has contact and through its action wait the response of the whole system. Each OEM defines during vehicle conceptualization the behavior of brake pedal that characterizes the pedal feel that in general reflects not only the characteristic from that vehicle but also from the entire brand. Technically, the term known as Pedal Feel means the relation between the force applied on the pedal, the pedal travel and the deceleration achieved by the vehicle. Such relation curves are also analyzed in conjunction with objective analysis sheets where the vehicle brake behavior is analyzed in test track considering different deceleration conditions, force and pedal travel. On technical literature, it is possible to find some data and studies considering the hydraulic brakes behavior.

Fuel power consumption for light duty vehicles has previously been shown to be proportional to vehicle traction power, with an offset for overhead and accessory losses. This allows the fuel consumption for an individual powertrain to be projected across different vehicles, missions, and drive cycles. This work applies the power-based model to commercial vehicles and demonstrates its usefulness for projecting fuel consumption on both regulatory and customer use cycles. The ability to project fuel consumption to different missions is particularly useful for commercial vehicles, as they are used in a wide range of applications and with customized designs. Specific cases are investigated for Light and Medium Heavy- Duty work trucks. The average power required by a vehicle to drive the regulatory cycles varies by nearly a factor 10 between the Class 4 vehicle on the ARB Transient cycle and the loaded Class 7 vehicle at 65 mph on grade.