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A study was conducted to assess the status of the antilock brake system (ABS) malfunction warning system on in-service air-braked commercial motor vehicles (CMVs). Data from a total of approximately 1,000 CMVs were collected in California, Ohio, Pennsylvania, and Washington in August and September of 2004 by enforcement personnel who had been trained to inspect the ABS warning lamp. With four categories covering warning lamp system functionality; no lamp (including lamp could not be found), lamp inoperational (including covered up or bulb removed), lamp ON (thus indicating an active ABS system fault), or OK, a snapshot of the operational status of the ABS malfunction warning system was created for the CMV population checked. Results indicate that about one in six power units manufactured on or after March 1, 1997 showed some problem with their ABS warning lamp system. One in three trailers manufactured on or after March 1, 1998 showed a problem.

Welding has been used extensively in automotive components design due to its flexibility to be applied in manufacturing, high structural strength and low cost. To improve fuel economy and reduce material cost, weight reduction by optimized structural design has been a high priority in auto industry. In the majority of heavy duty vehicle's chassis components design, the ability to predict the mechanical performance of welded joints is the key to success of structural optimization. FEA (finite element analysis) has been used in the industry to analyze welded parts. However, mesh sensitivity and material properties have been major issues due to geometry irregularity, metallurgical degradation of the base material, and inherent residual stress associated with welded joints. An approach, equilibrium-equivalent structural stress method, led by Battelle and through several joint industrial projects (JIP), has been developed.

Diesel oxidation catalysts and particulate filters are recognized as proven solutions for reducing diesel emission levels. However, such systems now operate under extreme and unique conditions in order to meet even more demanding emission regulations. Long term cold holding performance, erosion resistance and high temperature stability are issues that must be addressed to assure a robust design in diesel oxidation catalysts and diesel particulate filters. This paper will describe the application of new concepts for support mat systems and results from internal lab testing. It will describe three different case histories, present the design parameters, and compare results with traditional support mat systems.

The realistic simulation of vehicle-trailer combinations and the development of controllers for vehicle trains require comprehensive models for the dynamics of vehicle and trailer as well as a numerically feasible representation of the hitch. While the equations of motion for the two chassis can be reduced to systems of ordinary differential equations, introducing the coupling yields additional algebraic constraints on the relative vehicle-trailer motion. In this paper, a numerical algorithm for the simulation of vehicle trains is presented which overcomes the stability and drift-off phenomena known from the treatment of differential-algebraic equations and achieves real-time capability. Numerical results from simulations with a commercial vehicle dynamics program are shown proving its effectiveness for different vehicle-trailer combinations and demanding driving maneuvers.

A study was carried out to investigate, experimentally using a wind tunnel, the drag contribution (base drag) due to the flat-end of most van-type semi-trailers used for inter-city tractor-semi-trailer transportation. The study was focused on high cruise-speed operation of such vehicles at about 100 km/h (62.2 mile/h) a speed that can often be maintained for long distances on inter-city runs. It was found that it is possible to reduce overall aerodynamic drags significantly using a modestly tapered after-body terminating in a flat base. It was also shown that such after-bodies can be arranged to permit easy aft-end loading or unloading of trailers and that a reduction of engine fuel consumption at high-speed cruise on a level road of about 14% should be achievable when due allowance is also made for vehicle rolling resistance.

The reduction of particulate emissions from diesel engines is one of the most challenging problems associated with the exhaust air pollution control. Particulate emissions can be controlled by the adjustments of the combustion parameters of a diesel engine but these measures result in increased emissions of oxides of Nitrogen.Diesel particulate Filters (DPF) hold out the prospects of substantially reducing regulated particulate emissions but the question of the reliable regeneration of filters still remains a difficult hurdle. Many of the solutions proposed to date suffer from high engineering complexity, cost, thermal cracking, increased backpressure which in turn deteriorates diesel engine combustion performance. This paper presents an improved computer aided analytical approach for controlling Diesel soot particulate emission by Cyclone separator. Reduction of soot particles in the exhaust in turn reduces the Diesel Particulate Matter formation.

This paper presents good results obtained by an integrated work between experimental and numerical simulation areas of DaimlerChrysler do Brasil to identify an undesirable vibration phenomenon observed in the cabin of a medium truck prototype, characterized experimentally. The phenomenon was reproduced in the modal and dynamic analyses using FEA, consistent with the performed measurements in the vehicle. Modifications on the project of cabin suspension were developed and approved in vibration analyses, showing a reduction of the acceleration values to acceptable levels when evaluated in the prototype. Due to these modifications, an evaluation under durability criteria was necessary. The stress analyses showed necessity of alteration in some components of the cabin suspension. The prototypes, with the new cabin suspension, were submitted to test bench and evaluation in high severity road (off-road) and urban traffic aiming at the final product approval.

The Resolution 68/98 authorized the circulation of Long Combination Vehicles. Representative of freight vehicles evolution, these combinations should be observed taking into account their handling performance. Due to the quantity of articulations, they are subject to specific phenomena which affect their handling. The most relevant being “Rearward Amplification.” This concerns the increase in lateral deplacement of the last unit when compared with the first. The tractor-unit is subject to greater lateral acceleration, and has the potential to rollover. A study in rear amplification is essential for the evolution of freight vehicles, roads, road signals and in the training of drivers.

Every time we measure the terrain profiles we would get a different set of data due to the measuring errors and due to the fact that the linear tracks on which the measuring vehicle travels can not be exactly the same every time. However the data collected at different times from the same terrain should share the similar intrinsic properties. Hence it is natural to consider statistical modeling of the terrain profiles. In this paper we shall use the time series models with time being the distance from the starting point. We receive data from the Belgian Block and the Perryman3 testing tracks. The Belgian Block data are shown to behave like a uniformly modulated process([7]), i.e. it is the product of a deterministic function and a stationary process. The modeling of the profiles can be done by estimating the deterministic function and fit the stationary process with a well-known ARMA model. The Perryman3 data are more irregular.

With the Durability Transfer Concept a new methodology is presented, in which the fatigue damage under operational loading conditions in different areas of a vehicle is determined from the accelerations measured on the suspension. Thus long term measurements can be performed extremely cost efficient with only a 3 axis accelerometer on the suspension and a data logger. The accelerations are online processed, rain flow counted and by damage accumulation evaluated. The effort for the instrumentation of a vehicle and during measurements is reduced to a minimum. Counting into the rainflow matrices allows measurements without time limit. From the calculated damages of the accelerations the damage evolution of other quantities all over the vehicle is derived based on the durability transfer functions identified from short term measurements.

The U.S. Army uses the root mean square and power spectral density of elevation to characterize road/terrain (off-road) roughness for durability. This paper describes research aimed toward improving these metrics. The focus is on taking previously developed metrics and applying them to mathematically generated terrains to determine how each metric discerns the relative roughness of the terrains from a vehicle durability perspective. Multiple terrains for each roughness level were evaluated to determine the variability for each terrain rating metric. One method currently under consideration is running a relatively simple, yet vehicle class specific, model over a given terrain and using predicted vehicle response(s) to classify or characterize the terrain.

In this paper, we proposed a novel integrated vehicle chassis control configuration, which is based on the combination of vehicle vertical and lateral motion controls. Focusing on the improvement of vehicle handling and riding performance, particularly the active safety under critical driving condition, the purpose of Active Suspension (AS) in the integrated system is to achieve ride comfort quality and to provide more tyre cornering ability near the cornering force saturation regions, while the effect of Four Wheel Steering (4WS) is expected to eliminate the body side slip angle and to achieve an ideal yaw rate model following.

First, the energy consumption of a passive suspension via damper and the energy demand for an LQG optimal vehicle active suspension are investigated, showing valuable potentials for an active suspension with vibration energy regeneration. Then, the feasibility of energy regenerative approaches is discussed, and an electrical active suspension configuration is proposed with the description of its working principle and structure. The study on feasibility and configuration shows that the proposed configuration and control approach can be an effective approach for the active control and the energy regeneration of vehicle vibration. And potentially, it also can be useful for future electrical suspension design of electrical vehicles.

In this paper, we describe the development of multi-axis, accelerated durability tests for commercial vehicle suspension systems. The objective of the exercise is to design accelerated durability tests that have well-defined correlation with customer usage. The procedure starts with a definition of the vehicle's duty cycle based on the expected operational parameters, namely: road profile, vehicle speed, and warranty life. The second step is determining the durability proving ground test schedule such that the accumulated pseudo-damage (based on spindle loads) is representative of the vehicle's duty cycle. The third step in the process is developing a multi-axis laboratory rig test for the suspension system, such that the accumulated damage in the proving ground is replicated in a compressed time frame.

Soil cutting for preparing a proper seedbed with the purpose of crop production is tillage. Though tillage is a dynamic process, most of the previous studies are based on quasi-static analysis following the passive earth pressure theories. The focus of this research was to describe the mechanical behavior of soil under the action of a tillage tool from the dynamic perspective using fluid flow analysis. This paper describes the application of a commercially available, three-dimensional computational fluid dynamics (CFD) model to simulate and analyze dynamic tool interaction with soil during tillage. Soil has been considered as a Bingham material taking into account its non-Newtonian viscoplastic behavior. Simulations used a rectangular flow geometry based on the tool influence zone obtained from previous research. Soil flow behavior has been studied as a conduit with the interaction of a bluff body in the flow domain.

A numerical methodology using 3D computational fluid dynamics (CFD) was developed to simulate the water flows on vehicles in order to check the specifications under rain (visibility of door mirror by the driver, sealing…), or to evaluate washing efficiency (washing headlight, washing windshield …). The CFD method is constituted by a three step procedure. In the first step, the aerodynamic field around the vehicle is calculated with Powerflow software in a large domain. It uses a Lattice Boltzmann approach to solve airflow. The existing process of Powerflow computation developed by aerodynamic and aeroacoustic teams of Renault SAS was adapted to refine results in high gradients of velocity zones. In the second step, the field of air velocity vectors calculated with Powerflow is mapped towards a small domain where the water flow will be solved.

An existing tire model was investigated for additional normal load-dependent characteristics to improve the large truck simulations developed by the National Highway Traffic Safety Administration (NHTSA) for the National Advanced Driving Simulator (NADS). Of the existing tire model coefficients, plysteer, lateral friction decay, aligning torque stiffness and normalized longitudinal stiffness were investigated. The findings of the investigation led to improvements in the tire model. The improved model was then applied to TruckSim to compare with the TruckSim table lookup tire model and test data. Additionally, speed-dependent properties for the NADS tire model were investigated (using data from a light truck tire).

Using a simulation model, this study intends to provide a preliminary evaluation of whether semiactive dampers are beneficial to improving ride and handling in class 8 trucks. One of the great challenges in designing a truck suspension system is maintaining a good balance between vehicle ride and handling. The suspension components are often designed with great care for handling, while maintaining good comfort. For Class 8 trucks, the vehicle comfort is also greatly affected by the cab and seat suspensions. Dampers for passive suspensions are tuned “optimally,” using various metrics that the ride engineer may consider, for the condition in which the truck operates most frequently. In recent years, the popularity of semiactive dampers in passenger vehicles has prompted the possibility of considering them for class 8 trucks. In this study, the vehicle safety versus ride comfort trade-off is studied for a certain class of suspensions with semiactive fuzzy control.

A typical 10 tonne Midi-bus driveline includes an electric retarder device, located at the transmission output, which is used during vehicle braking thereby reducing service brake usage and wear. The retarder is activated via the brake pedal and operates down to speeds of 1 kph. To reduce cost and complexity it may be possible to delete the electric retarder when an infinitely variable transmission (IVT) powertrain is used in place of the standard 5 speed automatic transmission (5AT). The purpose of this study is to determine the amount of service brake usage, in terms of energy dissipation, for both the 5AT (with retarder) and IVT (without retarder) over the Millbrook London Transport Bus (MLTB) drive cycle. Validated MATLAB® dynamic models of both drivelines are used to calculate retarder and service brake usage.

The close proximity of seat suspensions to human body presents several challenges in terms of the perception of the suspension forces by the vehicle operator. This is particularly true of the suspensions with time-varying forces, such as semiactive seat suspensions. The major challenge in such suspensions is changing the suspension force from one state to under, without causing excessive amounts of dynamic jerk. This paper looks into the cause of dynamic jerk in semiactive suspensions with skyhook control, and presents two alternative implementations of skyhook control, called “no-jerk skyhook,” and “skyhook function,” for the purpose of this study. An analysis of the relationship between absolute velocity of the sprung mass and the relative velocity across the suspension is used to show the damping force discontinuities that result from skyhook control.