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The study of heavy vehicles rollover prediction, especially in algorithm-based heavy vehicles active safety control for improving road handling, is a challenging task for the heavy vehicle industry. Due to the high fatality rate caused by vehicle rollover, how to precisely and effectively predict the rollover of heavy vehicles became a hot topic in both academia and industry. Because of the strong non-linear characteristics of Human-Vehicle-Road interaction and the uncertainty of modeling, the traditional deterministic method cannot predict the rollover hazard of heavy vehicles accurately. To deal with the above issues, this paper applies a probability method of uncertainty to the design of a dynamic rollover prediction algorithm for heavy vehicles and proposes a novel algorithm for predicting the rollover hazard based on the combined empirical model of reliability index and failure probability.

Excessive vibration and poor controllability occur in many mobile fluid power applications, with negative consequences as concerns operators' health and comfort as well as machine safety and productivity. This paper addresses the problem of reducing oscillations in fluid power machines presenting a novel control technique of general applicability. Strong nonlinearities of hydraulic systems and the unpredictable operating conditions of the specific application (e.g. uneven ground, varying loads, etc.) are the main challenges to the development of satisfactory general vibration damping methods. The state of the art methods are typically designed as a function of the specific application, and in many cases they introduce energy dissipation and/or system slowdown. This paper contributes to this research by introducing an energy efficient active damping method based on feedback signals from pressure sensors mounted on the flow control valve block.

A novel method was developed to predict the free-stream velocity experienced by a traveling vehicle based on track-side anemometric measurements. The end objective of this research was to enhance the reliability of the prediction of free-stream conditions in order to improve the accuracy of aerodynamic drag coefficient (CD) assessments from track tests of surface vehicles. Although the technique was applied to heavy-duty vehicles in the present work, it is equally applicable to any vehicle type. The proposed method is based on Taylor’s hypothesis, a principle applied in fluid mechanics to convert temporal signals into the spatial domain. It considers that the turbulent wind velocity fluctuations measured at one point are due to the "passage of an unchanging pattern of turbulent motion over the point". The method is applied to predict the wind velocity that the vehicle will experience as it encounters a wind pattern detected earlier by an anemometer located upwind.

The increase in the global warming potential and increase in the pollution rate; people tend to adopt an alternative for the internal combustion engine vehicles. And the alternative leans toward electric vehicle technology. The pure electric vehicle technology also has the limitations of lesser energy storing capacity and higher charging time; needs further improvement. The advancements are Fuel Cell Electric Vehicles (FCEV) helps the vehicles to have a higher range and lesser filling time. The efficient thermal management system in FCEV leads higher energy utilization and increased vehicle range. This paper deals with the significance of thermal management energy consumption on the range and effective working of the FCEV System.

Tracked vehicles are widely used for agriculture, construction and many other areas. Due to high emissions, hybrid electric driveline has been applied to tracked vehicles. The hybrid powertrain design for the tracked vehicle has been researched for years. Different from wheeled vehicles, the tracked vehicle not only requires high mobility while straight driving, but also pursues strong steering performance. The paper takes the hybrid track-type dozers (TTDs) as an example and proposes an optimal design of a novel power-split powertrain for TTDs. The commercial hybrid TTD usually adopts the series hybrid powertrain, and sometimes with an extra steering mechanism, which has led to low efficiency and made the structure more complicated. The proposed three-planetary-gear power-split hybrid powertrain can overcome the problems above by utilizing the characteristics of planetary gear sets.

In the last decades, the locomotion of wheeled and tracked vehicles on soft soils has been widely investigated due to the large interest in planetary, agricultural, and military applications. The development of a tire-soft soil contact model which accurately represents the micro and macro-scale interactions plays a crucial role for the performance assessment in off-road conditions since vehicle traction and handling are strongly influenced by the soil characteristics. In this framework, the analysis of realistic operative conditions turns out to be a challenging research target. In this research work, a semi-empirical model describing the interaction between a tire and homogeneous and fine-grained soils is developed in Matlab/Simulink. The stress distribution and the resulting forces at the contact patch are based on well-known terramechanics theories, such as pressure-sinkage Bekker’s approach and Mohr-Coulomb’s failure criterion.

This study provides a numerical evaluation of the dynamic coupling that exists between the powertrain, suspensions, and tire dynamics in class 8 trucks. The spatial dynamics of the driveline, including the offset angels that commonly exist in practice, are modeled along with a lumped-parameter representation of the suspension and tire dynamics in vertical, longitudinal, and torsional directions. The model is used to show how the suspension dynamics and the angle change that it causes in driveline geometry can affect the vibrations resulting from the powertrain. The numerical model is also used for a parametric study in which the effect of various suspension and powertrain parameters on the dynamic coupling that exists between the two is evaluated.

The aerodynamic characteristics of automobiles have received substantial interest recently. Detailed knowledge of vehicle aerodynamics is essential to improve fuel efficiency and enhance stability at high-speed cruising. In this study, a numerical simulation has been carried out for three-dimensional turbulent flows around a commercial bus body. Also, the effect of a rear-spoiler attached at the rear end of the bus body was investigated. The Navier-Stokes equation is solved with the SIMPLE method in a general curvilinear coordinates system. RNG k- ε turbulence model with the MARS scheme was used for evaluating aerodynamic forces, velocity and pressure distribution. The results show that complex wake structure in the immediate rear of the bus body has been confirmed. The rear-spoiler modifies the near wake structure and decreases aerodynamic drag and improvement in lift force was achieved.

The pulsating flow in a duct with a junction was studied numerically using a Random-Choice Method and the experiments were carried out to check if this numerical simulation is valid or not. As a result, good agreement was found between the experiment and numerical calculation. Concerning the location of the shock wave the agreement was excellent. The Random-Choice Method may be applied to real reciprocating engines by coupling it to a multi-dimensional in-cylinder simulation.

In this paper, computation fluid dynamics (CFD) simulations are employed to describe the effect of flow parameters on the formation of soot and NOx in a heavy duty engine under low load and high load. The complexity of diesel combustion, specially when soot, NOx and other emissions are of interest, requires using a detailed chemical mechanism to have a correct estimation of temperature and species distribution. In this work, Multiple Representative Interactive Flamelets (MRIF) method is employed to describe the chemical reactions, ignition, flame propagation and emissions in the engine. A phenomenological model for soot formation, including soot nucleation, coagulation and oxidation with O2 and OH is incorporated into the flamelet combustion model. Different strategies for modelling NOx are chosen to take into account the longer time scale for NOx formation. The numerical results are compared with experimental data to show the validity of the model for the cases under study.

A one thousand horsepower machine to be used for milling and excavating concrete and asphalt pavement is currently being produced. The machine was designed primarily for large pavement removal or surface texturing jobs. This paper contains general description of the machine, its overall size, power distribution, drive configuration, etc. It is significant that the machine represents a proven, quick economically sound method of resurfacing, recycling, restoring and reclaiming our nations deteriorating highway system.

It is apparent that a new generator and regulator design is needed to supply the additional electrical loads and meet the requirements for durability, reliability, and environmental protection on earthmoving equipment. The author discusses the d-c and alternator type systems which have been used to supply electrical needs. A detailed analysis of the integral charging system is presented. This system overcomes many of the shortcomings of the present electrical systems and, because it has a minimum number of moving parts, it is potentially the most reliable charging system in use on heavy duty equipment.

A Department of Energy funded research project currently in the final stages of completion has resulted in a web-based tool that gives non-expert users the ability to add aerodynamic devices to a CFD model of a single bogie trailer and generalized tractor model. This model was used to assess the aerodynamic performance of skirt geometries. The skirts were defined using 5 independent geometric parameters and 2 installation parameters. These parameters allow enough freedom in the geometry definition to capture the shape and installation position and angle of a wide number of commercially available skirts on the market today. Using a Design of Experiments approach, the aerodynamic drag response of the truck and trailer to any parametric change in the skirt geometry has been determined across a range of yaw angles.

The insertion loss of louvered terminations positioned at the end of a rectangular duct is determined using acoustic finite element analysis. Insertion loss was determined by taking the difference between the sound power with and without the louvers at the termination. Analyses were conducted in the plane wave regime and the acoustic source was anechoic eliminating any reflections from the source. The effect of different louver configurations on insertion loss was examined. Parameters investigated included louver length, angle, and spacing between louvers. Based on the analyses, equations were developed for the insertion loss of unlined louvers.

The variables affecting bending strength of spur gear teeth have been reviewed with the purpose of showing the magnitude and trend in the change of strength as a result of a change in a variable. Also presented is a unique interactive computer program giving numerical results as well as displaying the tooth profile as it is being generated by the hob. This demonstrates the dramatic change in the tooth profile which can result while either developing the maximum strength of the tooth or optimizing the strength of a gearset.

The objective of this paper is to identify patterns of behavior exhibited by successful project teams working in the commercial vehicle environment. Case studies of both successful and unsuccessful project teams were performed. Concepts that repeated themselves and appeared to contribute to the success of the overall project have been identified as patterns. Recurring concepts that appeared to have contributed to the ultimate failure of a project were identified as antipatterns.

The material presented in this paper addresses the following questions of the engineer of the ‘80’s: 1. How can an (earthmoving) engineer be successful in the ‘80’s? 2. Should he isolate himself in his work? 3. Are there special needs in the ‘80’s? 4. What should he do-personally-to succeed and to improve the world in which we live? 5. Can the engineer help solve specific problems facing us now? 6. Can today’s problems-unemployment, inflation, world unrest, competition from new sources around the world, social unrest, energy limitations, pollution, and others, be met directly by the engineer with any success?

In commercial vehicles, the exhaust brake assists the service brake to share the excess load and is used as an auxiliary brake to assist with the safety of the engine and the service brake on downhill slopes. To meet the customer's demand for auxiliary brakes, the specification of auxiliary brakes must be determined at the product proposal stage. In this study, performance design was conducted to derive exhaust brake specifications that fit the customer's requirements. For performance design, a system model was created and key design factors with high performance contribution were extracted. Optimal specifications were derived from parameter studies for key design factors. Additionally, performance analysis was performed with design tolerances using the performance design model. Performance was verified through actual vehicle evaluation and design specifications were confirmed.

The objective of this study was to evaluate iso-butanol (C4H9OH) as an alternative fuel for spark ignition engines. Unlike methanol (CH3OH) and ethanol (C2H5OH), iso-butanol has not been extensively studied in the past as either a fuel blend candidate with gasoline or straight fuel. The performance of a single cylinder engine (ASTM=CFR) was studied using alcohol-gasoline blends under different input parameters. The engine operating conditions were: three carburetor settings (three different fuel flow rates), spark timings of 5°, 10°, 15°, 20°, and 25° BTDC, and a range of compression ratios from a minimum of 7.5 to a maximum of 15 in steps of one depending on knock. The fuels tested were alcohol-gasoline blends having 5%, 10%, 15%, and 20% of iso-butanol, ethanol, and methanol. And also as a baseline fuel, pure gasoline (93 ON) was used. The engine was run at a constant speed of 800 RPM.

Recent research on carburized steels has demonstrated a correlation between the toughness properties of a carburized steel and the fatigue performance in combined load testing (high-cycle fatigue plus overload). The data presented suggest that, for applications where loads above the fatigue limit are encountered, both processing and alloying must be considered. Results from a number of investigations are reviewed to illustrate that high-cycle fatigue properties are controlled primarily by the processing, whereas toughness characteristics, such as resistance to random cyclic loading, are a result of the alloying.