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Patents granted recently to Mr. Rode have changed the industry capability to adjust and verify wheel-end bearings on trucks. Until now it was believed1 that there was nothing available to confirm or verify the most desirable settings of preload on these bearings. The new, breakthrough invention is a tool and spindle-locking nut that permit quick and accurate wheel bearing adjustment by utilizing direct reading force measurement. Bearings can be set to either SAE recommended preloads or specific endplay settings. The author has been working on bearing adjustment methods for industrial applications for over forty years, and considers these inventions to be his most important breakthrough for solving this elusive bearing adjustment problem. Consistent wheel bearing preload adjustment was not possible before, even though it was widely known to achieve the best wheel performance as noted in SAE specification J2535 and re-affirmed in 2006 by the SAE Truck and Bus Wheel Subcommittee.

A heavy truck wind tunnel test program is currently underway at the Langley Full Scale Tunnel (LFST). Seven passive drag reducing device configurations have been evaluated on a heavy truck model with the objective of understanding the practical limits to drag reduction achievable on a modern tractor trailer through add-on devices. The configurations tested include side skirts of varying length, a full gap seal, and tapered rear panels. All configurations were evaluated over a nominal 15 degree yaw sweep to establish wind averaged drag coefficients over a broad speed range using SAE J1252. The tests were conducted by first quantifying the benefit of each individual treatment and finally looking at the combined benefit of an ideal fully treated vehicle. Results show a maximum achievable gain in wind averaged drag coefficient (65 mph) of about 31 percent for the modern conventional-cab tractor-trailer.

This paper presents a simulation of the cooling airflow and surface temperatures of a midsize truck. The simulation uses full detailed geometry of the truck. Performance of the under-hood cooling airflow is analyzed and potential design changes leading to better cooling airflow are highlighted. Surface temperature over certain under-hood part is studied. Possible optimizations using various material and configurations are proposed. It is shown that the presented simulation approach provides valuable information to evaluate cooling system and thermal protection performance. Fast design iterations can be achieved using this approach.

The objective of this research project was to compare B20 (20% biodiesel fuel) and ultra-low-sulfur (ULSD) diesel-fueled buses in terms of fuel economy, vehicle maintenance, engine performance, component wear, and lube oil performance. We examined 15 model year (MY) 2002 Gillig 40-foot transit buses equipped with MY 2002 Cummins ISM engines. The engines met 2004 U.S. emission standards and employed exhaust gas recirculation (EGR). For 18 months, eight of these buses operated exclusively on B20 and seven operated exclusively on ULSD. The B20 and ULSD study groups operated from different depots of the St. Louis (Missouri) Metro, with bus routes matched for duty cycle parity. The B20- and ULSD-fueled buses exhibited comparable fuel economy, reliability (as measured by miles between road calls), and total maintenance costs. Engine and fuel system maintenance costs were also the same for the two groups after correcting for the higher average mileage of the B20 group.

An effort was undertaken to capture the relationship between the output of mass flow sensors and the input rate of mass flow for harvesting combines with yield monitors. Different types of models were considered that characterize this relationship and that can be applied to a variety of mass flow sensor technologies. Issues such as implementation during harvesting and calibration of these sensors and models were explored. Additionally, an example of such a model and its validation against experimental data was examined. For small-scale laboratory experiments, the model was shown to closely capture the general trend of the data as well as to yield reasonable estimates of the mass flowing through the system based on the sensor output. For large-scale experiments, the model was able to be fitted to the experimental data, and to estimate mass flow rate with relatively low errors across a variety of operating conditions.

The soot distribution as function of ambient O₂ mole fraction in a heavy-duty diesel engine was investigated at low load (6 bar IMEP) with laser-induced incandescence (LII) and natural luminosity. A Multi-YAG laser system was utilized to create time-resolved LII using 8 laser pulses with a spacing of one CAD with detection on an 8-chip framing camera. It is well known that the engine-out smoke level increases with decreasing oxygen fraction up to a certain level where it starts to decrease again. For the studied case the peak occurred at an O₂ fraction of 11.4%. When the oxygen fraction was decreased successively from 21% to 9%, the initial soot formation moved downstream in the jet. At the lower oxygen fractions, below 12%, no soot was formed until after the wall interaction. At oxygen fractions below 11% the first evidence of soot is in the recirculation zone between two adjacent jets.

In this paper, we are interested in developing a robust tire-force estimator for heavy duty vehicles. We use a combined model of the articulated vehicle: a yaw plane model for the chassis motion and a vertical plane model for the axles. In the proposed method, we make use of the on-board available sensors to which low-cost sensors are added. In order to optimize the sensors configuration, a robust exact differentiator is used in order to obtain accelerations from the measured velocities. Once the differentiation is obtained, the model is inverted to determine the unknown input forces. The approach is validated by comparing the estimation results to those given by the software simulator prosper .

The application of stability systems on heavy vehicles clearly has numerous advantages, when the cost of the cargo, the service life of vehicles, and the vehicle potential for damage are taken into account. The primary objective of such systems is to assist the driver to maintain control in the face of uncertain driving conditions. The dynamic effects of such system, however, are not widely tested by the industry. The study presented in this paper will present an evaluation of the effects of full and partial stability systems on tractor-trailers using hardware-in-the-loop simulation. With the advancement of simulation capabilities that enables the repeatability of maneuvers, the study presented attempts to provide various deterministic “what-if” scenarios under various vehicle stability system combinations.

Recent fluctuation in oil prices has generated interest in fuel-efficient vehicles, especially their aerodynamic profile. The literature indicates that turbulent wakes that form at the rear end of the vehicle contribute to vehicle drag in a major way. Minor studies have addressed the effects of rear-end wall angle to the drag force through effecting the wake behind the vehicle; however, this study assesses the reduction of drag using angular side walls. A previous simulation of external airflow over Ahmed's body was investigated, utilizing the k-ω SST models. Different angles of side walls were analyzed, and a maximum 36.85% reduction in drag coefficient was achieved using an angular rear side wall. The turbulent model was validated and the effectiveness of angular rear side walls thus proven. The study then simulated the flow for a road vehicle model to investigate the real world effect of angular rear side walls.

With the introduction of advanced digital road maps, which include information on the slope and curve radius of the highways, predictive control for standard and hybrid commercial vehicles, based on these maps, is about to be released by the vehicle manufacturers. For example, intelligent predictive cruise control has been announced for introduction in 2012 by Scania and Daimler. In addition, hybrid commercial city buses like MAN's Lion's City Hybrid have already been implemented. But the question remains about the type of vehicle suitable for the implementation of predictive intelligent concepts, due to the high investment cost compared to the sometimes relatively low operating cost savings.

This research was to model a 6×4 tractor-trailer rig using TruckSim and simulate severe braking maneuvers with hardware in the loop and software in the loop simulations. For the hardware in the loop simulation (HIL), the tractor model was integrated with a 4s4m anti-lock braking system (ABS) and straight line braking tests were conducted. In developing the model, over 100 vehicle parameters were acquired from a real production tractor and entered into TruckSim. For the HIL simulation, the hardware consisted of a 4s4m ABS braking system with six brake chambers, four modulators, a treadle and an electronic control unit (ECU). A dSPACE simulator was used as the “interface” between the TruckSim computer model and the hardware.

The main purpose of this research is to investigate the optimal design of pipeline diameter in an air brake system in order to reduce the response time for driving safety using DOE (Design of Experiment) method. To achieve this purpose, this paper presents the development and validation of a computer-aided analytical dynamic model of a pneumatic brake system in commercial vehicles. The brake system includes the subsystems for brake pedal, treadle valve, quick release valve, load sensing proportional valve and brake chamber, and the simulation models for individual components of the brake system are established within the multi-domain physical modeling software- AMESim based on the logic structure. An experimental test bench was set up by connecting each component with the nylon pipelines based on the actual layout of the 4×2 commercial vehicle air brake system.

Due to the diversity of Heavy Duty Vehicles (HDV), the European CO2 and fuel consumption monitoring methodology for HDVs will be based on a combination of component testing and vehicle simulation. In this context, one of the key input parameters that need to be accurately defined for achieving a representative and accurate fuel consumption simulation is the vehicle's aerodynamic drag. A highly repeatable, accurate and sensitive measurement methodology was needed, in order to capture small differences in the aerodynamic characteristics of different vehicle bodies. A measurement methodology is proposed which is based on constant speed measurements on a test track, the use of torque measurement systems and wind speed measurement. In order to support the development and evaluation of the proposed approach, a series of experiments were conducted on 2 different trucks, a Daimler 40 ton truck with a semi-trailer and a DAF 18 ton rigid truck.

This paper reviews fuel-saving technologies for commercial trailers, provides an overview of the trailer market in the U.S., and explores options for policy measures at the federal level that can promote the development and deployment of trailers with improved efficiency. For trailer aerodynamics, there are many technologies that exist and are in development to target each of the three primary areas where drag occurs: 1) the tractor-trailer gap, 2) the side and underbody of the trailer, and 3) the rear end of the trailer. In addition, there are tire technologies and weight reduction opportunities for trailers, which can lead to reduced rolling resistance and inertial loss. As with the commercial vehicle sector, the trailer market is diverse, and there are a variety of sizes and configurations that are employed to meet a wide range of freight demands.

Safety and minimal transit time are vital during transportation of essential commodities and passengers, especially in winter conditions. Icy roads are the worst driving conditions with the least available friction, leaving valuable cargo and precious human lives at stake. The study investigates the available friction at the tire-ice interface due to changes in key operational parameters. Experimental analysis of tractive performance of tires on ice was carried out indoor, using the terramechanics rig located at the Advanced Vehicle Dynamics Laboratory (AVDL) at Virginia Tech. The friction-slip ratio curves obtained from indoor testing were inputted into TruckSIM, defining tire behavior for various ice scenarios and then simulating performance of trucks on ice. The shortcomings of simulations in considering the effects of all the operational parameters result in differences between findings of indoor testing and truck performance simulations.

In this research paper, a novel train traction system is described. In this system, the vehicle is lifted like a hovercraft by air cushion and the traction is achieved by using horizontally mounted all-wheel drive. Chance of derailment is completely eliminated and wherein even in the event of failure of few traction wheel stations during run, the train remains mobile with absolute safety even at high speeds. All-wheel drive traction is powered by overhead electrification to maintain high power to weight ratio and faster acceleration. In the present invention, no rail is used. This eliminates the enormous cost of laying the complex and expensive railway tracks. Other advantages include the lack of exhaust fumes and carbon emissions at point of use especially in countries where electricity comes primarily from non-fossil sources, less noise, lower maintenance requirements of the traction units.

Several drive cycles have been developed to describe heavy-duty class 8 truck tractor operations. However, regional delivery operations, consisting of a mix of urban and over-the-road driving using highways to access several delivery/pick-up sites in dense urban areas, have not been well described. With funding from the U.S. Army National Automotive Center, the High-efficiency Truck Users Forum (HTUF) developed two drive cycles in an effort to better describe the full range of Class 8 truck tractor operations, which in total consumed about 30 billion gallons of diesel in the United States in 2010. This paper describes the rational for and the process to develop two regional delivery drive cycles: HTUF Regional Delivery #1 and HTUF Regional Delivery #2. These cycles were developed from more than eight months of cumulative data collected on six diesel Class 8 truck tractors operating across North America and representing several types of truck vocations.

This paper presents a novel methodology to develop and validate fuel consumption models of Refuse Collecting Vehicles (RCVs). The model development is based on the improvement of the classic approach. The validation methodology is based on recording vehicle drive cycles by the use of a low cost data acquisition system and post processing them by the use of GPS and map data. The corrected data are used to feed the mathematical energy models and the fuel consumption is estimated. In order to validate the proposed system, the fuel consumption estimated from these models is compared with real filling station refueling records. This comparison shows that these models are accurate to within 5%.

The emergence of tougher environmental legislations and ever increasing demand for increased ride comfort, fuel efficiency, and low emissions have triggered exploration and advances towards more efficient vehicle gearbox technologies. The growing complexity and spatial distribution of such a mechatronic gearbox demands precise timing and coordination of the embedded electronics, integrated sensors and actuators as well as excellent overall reliability. The increased gearbox distributed systems have seen an increased dependence on sensors for feedback control, predominantly relying on hardware redundancy for faults diagnosis. However, the conventional hardware redundancy has disadvantages due to increased costs, weight, volume, power requirements and failure rates. This paper presents a virtual position sensor-based Fault Detection, Isolation and Accommodation (FDIA), which generates an analytical redundancy for comparison against the actual sensor output.

Fuel consumption reduction on medium-duty tactical truck has and continues to be a significant initiative for the U.S. Army. The Crankshaft-Integrated-Starter-Generator (C-ISG) is one of the parallel hybrid propulsions to improve the fuel economy. The C-ISG configuration is attractive because one electric machine can be used to propel the vehicle, to start the engine, and to be function as a generator. The C-ISG has been implemented in one M1083A1 5-ton tactical cargo truck. This paper presents the experimental assessments of the C-ISG hybrid truck characteristics. The experimental assessments include all electric range for on- and off-road mission cycles and fuel consumption for the high voltage battery charging. Stationary tests related to the charging profile of the battery pack and the silent watch time duration is also conducted.