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While much research has focused on improving terrain mobility, energy and fuel efficiency of terrain trucks, only a limited amount of investigation has gone into analysis of power distribution between the driving wheels. Distribution of power among the driving wheels has been shown to have a significant effect on vehicle operating characteristics for a given set of operating conditions and total power supplied to the wheels. Wheel power distribution is largely a function of the design of the driveline power dividing units (PDUs). In this paper, 6×6/6×4 terrain truck models are analyzed with the focus on various combinations of PDUs and suspension systems. While these models were found to have some common features, they demonstrate several different approaches to driveline system design.

In this paper, a method for directional control of articulated heavy vehicles is proposed. The tractor yaw rate, the tractor lateral velocity and the articulation angle are selected as the control variables. The desired values of these states are defined in such way to improve the maneuverability and the stability of the articulated vehicle. A linear quadratic regulator controller is designed based on the linear model of the articulated vehicle to make the control variables follow the desired responses. Furthermore, a nonlinear 14 Degrees of freedom (DoF) model is developed to evaluate the proposed control method. The significant effect of the proposed method on improving the directional behavior of the articulated vehicle is proved through the simulations of the high speed lane change maneuver on a slippery road.

The 9-meter wind tunnel of the National Research Council (NRC) of Canada is commonly employed in testing of class 8 tractors at full- and model-scales. In support of this work a series of tests of an identical model at full- and half-scale were performed to investigate some of the effects resulting from simulation compromises. Minimum Reynolds Number considerations drive the crucial decisions of what scale and speed to employ for testing. The full- and half-scale campaigns included Reynolds Number sweeps allowing conclusions to be reached on the minimum Reynolds number required for testing of fully-detailed commercial truck models. Furthermore the Reynolds sweeps were repeated at a variety of yaw angles to examine whether the minimum Reynolds Number was a function of yaw angle and the resulting flow regime changes. The test section of the NRC 9-meter wind tunnel is not sufficiently long to accommodate a full-scale tractor and a typical trailer length of 48′ or more.

There is a clear trend for major truck manufacturers to expand outside their traditional “home markets,” and it appears almost inevitable that a global truck industry will eventually become a reality. It is therefore of interest to speculate whether such global manufacturers will be able to serve world markets with a single product line, i.e., a world truck. This paper examines the factors that have brought about variations in the form and function of trucks (3.5 tons and up) in different regions of the world, as well as the trends toward convergence (or lack thereof) of these design variations that are now taking place. The factors that appear to have influenced variation and which are considered here include: historical development, source of vehicles (manufacturing base), regulations, geography, technology, and special market factors.

To get the useful information for a ventilation in tunnels, two-dimensional turbulence flow fields around trucks in tunnels are, as the first step, calculated numerically, while changing the vehicular gap and ejecting speed of gas exhausted from the rear of truck. In addition, to compare the calculated and measured results, the flow patterns in tunnel are visualized by an optical method of laser light sheet and pressure distributions along to center line of the truck are measured by a pressure transducer. Consequently, relationships between the flow and diffusion patterns of exhausted gas and aerodynamic characteristics around the truck are discussed for various vehicular gaps. Furthermore, the pressure coefficients and flow patterns obtained by calculation are found to be in reasonable agreement with those obtained from measurement.

From time to time, over many years, MIRA (the Motor Industry Research Association) has carried out surveys of the handling behaviours of various classes of road vehicles. The most recent investigation has concerned modern European intercity buses, or coaches as they are termed in Britain. The work was sponsored by the British Government together with five vehicle manufacturers who each supplied one bus. The main aim of the work was to ascertain the handling characteristics of a sample of modern buses in terms of both absolute behaviour and relative behaviour compared to other classes of road vehicles. However, the manufacturers sponsoring the work were also very interested to discover any correlation between various features of layout of the vehicles and the handling characteristics.

New communication and information processing technology is significantly changing the world of logistics and transportation. A new program established by the U.S. Department of Transportation, known as the Intelligent Vehicle-Highway System (IVHS) Program, seeks to apply this technology to transportation in an organized fashion. The goal is to improve the efficiency and safety of the highway system. Many of the new technologies have the potential to allow the automation of the hazard communication process during hazardous material transportaiton. This paper identifies and discusses some of the potential applications of IVHS technology to the hazardous material transportation environment.

This paper reviews the history of heavy truck noise legislation in the U.S. Both legislative activity and the response of vehicle and engine manufacturers are described. The cost cycle experienced by manufacturers is also described. Over a period of time, the costs involved in meeting noise regulations are reduced without increasing truck noise levels. Data is presented which shows that public complaints about truck noise are often related to modified vehicle exhaust systems. The data shows that modified exhaust systems have an especially severe effect on compression brake noise. Additional results suggest that some trucks with extensively modified exhaust systems may be able to pass the in-use noise standard.

In January 1989, the California Energy Commission called on engine and coach manufacturers to identify the concerns and obstacles to be overcome in order to develop a School Bus Demonstration Program using alternative fuels. Working closely with Detroit Diesel Corporation, Crown Coach undertook the development to apply DDC's methanol-fueled 6V-92TA engine in the Crown transit style heavy-duty school bus. Safety was the prime consideration in designing a vehicle that not only exceeded FMVSS-301 Fuel System Integrity requirements and State specifications, but also met the anticipated needs of the operating school districts and potential concerns of parents.

The paper will review existing seals used in off-highway heavy equipment, both radial lip seal applications and face type seal applications in general use on track vehicles. With the trend towards improved reliability and durability, together with the never ending quest for quality and product improvements, the paper will discuss a number of seal development programs which will result in products that meet the new and projected future requirements for seals from the off-highway heavy equipment manufacturers.

The key words in the marketplace for off-highway vehicles are durability, performance, and efficiency. A manufacturer of these vehicles recognizes that one way to successfully address these needs is by a well thought through electronics design. With the computer sophistication now being incorporated into off-highway vehicles, engineers must work closely to assure electromagnetic compatibility (EMC) of the entire system. A properly established EMC program extending from concept to final design will support each of a product's specified operations and still function as an integrated whole. This paper describes the process for designing the EMC for an off-highway vehicle.

SCR technology has proven its ability to significantly reduce NOX emissions to fulfill future emission legislations. The key to this technology is the generation of ammonia on-board to reduce the NOX. Ammonia generation catalyst systems need to be highly efficient in a limited packaging space. The influence of physical parameters of the catalyst's substrate such as thermal mass, hydraulic diameter and geometric surface area on catalyst's efficiency is well known, but the transport processes in structured metallic substrates are still an object of investigation. A numerical study for 3 structured substrates was carried out, and the results were compared with experimental data. An increase of the volumetric efficiency was found when structured substrates were applied. The numerical results are in good accordance with the experimental data and therefore proven to be an excellent tool for channel design optimization.

The future demand for more fuel efficient and cleaner vehicles and machinery is a huge engineering challenge. On one side, regulated particulate matter reduction and gaseous exhaust emissions are addressed by higher EGR rates and optimized combustion technology. On the other side, after treatment components are added. Very compact systems are required and pressure drop need to be engineered to a minimum to minimize negative effects on fuel consumption. This paper describes the usage of thermodynamically optimized advanced metallic substrates components to address packaging at minimum exhaust flow resistance. The newly developed metallic cost-effective substrates with structured foil technology are engineered for lowest flow restriction and highest effectiveness.

Electronic stability control (ESC) is being incorporated as a standard feature in almost all passenger cars since it is highly effective in reducing road accidents. Moreover, many commercial vehicles can be equipped with ESC, which includes roll stability control. ESC determines vehicle stability on the basis of the driver's operation, vehicle behavior, and preset control parameters. When the vehicle stability is likely to be lost, control intervenes to stabilize the vehicle. The characteristics of commercial vehicles affect the ESC parameters and vary significantly with the payload (e.g., weight and height of the cargo and the loading state). Therefore, the control parameters need to be adjusted according to the loading conditions to enhance vehicle stability and avoid unnecessary control intervention. We have developed an ESC that improves the yaw and roll stability of trucks. For this development, accurate evaluation of the payload states is important.

Build variation and tolerance stack up are unavoidable in the vehicle manufacturing process, not only for individual components and assemblies but also for the vehicle at large. Deviations across several components, each within tolerance limits, could ultimately have a significant effect on vehicle aerodynamic performance. The objective of this study is to quantify the impact of several such build variations on vehicle drag. A Lattice-Boltzmann-based simulation method was used in conjunction with design of experiments to construct a Kriging response surface interpolation model to efficiently characterize the impact of 17 different body and chassis build variations on the aerodynamic drag of a VNL 780 tractor trailer at a nonzero yaw angle. The top three parameters with greatest aerodynamic impact were then evaluated at the opposite symmetric yaw angle to understand the impact of build variation on vehicle asymmetry.

Abstract This research develops a hierarchical control strategy to improve the stability of multi-axle electric vehicles with in-wheel motors while driving at high speed or on low adhesion-coefficient roads. The yaw rate and sideslip angle are chosen as the control parameters, and the direct yaw-moment control (DYC) method is employed to ensure the yaw stability of the vehicle. On the basis of this methodology, a hierarchical yaw stability control architecture that consists of a state reference layer, a desired moment calculation layer, a longitudinal force calculation layer, and a torque distribution layer is proposed. The ideal vehicle steering state is deduced by the state reference layer according to a linear two-degree-of-freedom (2-DOF) vehicle dynamics model.

This document specifies the format, content and parameters for a product identification numbering system for off-road recreation vehicles, based on the PIN structure for earth-moving machinery in ISO 10261:2002E and is not applicable to the identification of components or attachments. This standard applies only to the off-road recreation vehicle industry and does not impose parameters for the marine, lawn and garden, silviculture, husbandry, construction or earth moving sectors.

Global environmental and economic concerns of today's world dictate strict requirements for modern heavy duty engines, especially in emissions, noise control, power generation, and extended oil drain intervals. These requirements lead to increased stresses imposed on lubricants in modern heavy duty engines. At the same time, the original equipment manufacturers (OEMs) desire additional fuel economy from the lubricating oil, requiring the use of lower viscosity lubricants to minimize frictional losses in the engine. These lower viscosity oils are subjected to increased stresses in the engine and need to provide robust performance throughout their lifetime in order to protect engine parts from wear and damage. One of the most important lubricant qualities is to maintain viscosity throughout the drain interval and thus provide continuous engine protection.

Abstract The present study assesses the use of a two-equation eddy-viscosity turbulence model, which is a shear-stress transport (SST) k-ω turbulence model, in two-way coupled aerodynamics and vehicle dynamics simulation of a heavy ground vehicle subjected to crosswind. The obtained results are compared with the corresponding results of the improved delayed detached-eddy simulation (IDDES) conducted at similar conditions from the previous literature. The aim is to evaluate the effects of different turbulence models used in aerodynamics simulations to resolve the vehicle dynamics results in two-way coupled simulations. The results present that the absolute relative percent differences between the lateral displacement, yaw angle and roll angle results of the SST k-ω and the IDDES simulations are less than 1%, 3%, and 10%, respectively.

Abstract Articulated vehicles contribute to the major portions of cargo transport through roads. Fifth wheel (FW) is an important component in these vehicles, which acts as the bridge between tractor and trailer and is often used as a parameter to adjust the axle loads. Ride and comfort studies linked to FW position exist. However, its influence on durability is often not considered seriously. In this article, three different FW positions placed at 200 mm, 400 mm, and 600 mm in front of the rear axle are studied virtually on a 4×2 tractor with three-axle semitrailer combination. To assess the risk associated with FW movement, acceleration-based pseudo-relative damage, power spectral density (PSD), and level crossing plots are analyzed for each FW position. Further, fatigue analysis is done on the cab structural components to understand the durability. Outcome shows that the FW position has an influence in determining the cab dynamics and durability of the components to a great extent.