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Several configurations of truck tractor sleeper cabs were tested and modeled to investigate the potential to reduce heating and cooling loads. Two trucks were tested outdoors and a third was used as a control. Data from the testing were used to validate a computational fluid dynamics (CFD) model and this model was used to predict reductions in cooling loads during daytime rest periods. The test configurations included the application of standard-equipped sleeper privacy curtain and window shades, an optional insulated or arctic sleeper curtain, and insulated window coverings. The standard curtain reduced sleeper area heating load by 21% in one test truck, while the arctic curtain decreased it by 26%. Insulated window coverings reduced the heating load by 16% in the other test truck and lowered daytime solar temperature gain by 8°C. The lowered temperature resulted in a predicted 34% reduction in cooling load from the model.

The increasing complexity of the electrical and electronic systems on trucks requires a more sophisticated electrical control system. Replacing many of the discrete electronic controls and wiring with a central Electrical System Controller (ESC) allows for easier integration of system components and improved system response. The use of software control within the Electrical System Controller, provides opportunities for enhanced system capabilities and a fluid platform for future development. This paper examines the software architecture employed within an Electrical System Controller and also examines the factors that govern the software's design. These include a requirement for the ESC to be highly configurable to accommodate a variety of features desired by customers.

Engineering tests that do not impact business decisions waste time, budgets and morale. This paper will consider input and output information for the test process-specifically in vehicle dynamics and structural integrity labs. Uncontrolled test processes are unlikely to fulfill expectations. Conversely, the process may be closely defined in a widespread specification, and yet not answer the question at hand. Potential downstream impacts of loosely defined technical details will be discussed. Topics include selection of transducers, recording parameters, filtering and analysis techniques. Physics of common environmental loading are presented, along with implications for both the test plan and later use of the test data. Case studies as both a truck, bus and railroad test services provider and consumer will be discussed.

The increased use of power field-effect transistors instead of power relays for controlling electrical loads on vehicles has created an opportunity for the development of a software based virtual fuse. This development has several important aspects to the vehicle OEM. Not only will the cost of the fuse be saved along with the cost of the fuse holder, but also perhaps the largest cost associated with using a traditional fuse: the wiring to and from the fuse. In commercial vehicles, the variability of one vehicle to the next may force different circuits to occupy the same physical space on the different vehicles. These differing circuits may also require different values of fuse elements. Ensuring that the correct fuse value is installed under these conditions can be a difficult task at best. Having a software based virtual fuse that can be programmed to match the vehicle configuration can eliminate having an unprotected circuit due to an assembly error.

This paper will review and discuss the advantages and disadvantages of utilizing modular systems in vehicle assembly, particularly Medium Duty, Severe Service, and Heavy Duty trucks. Focus will be put on cab interior modules, as they were developed for the International 4000, 7000, and 8000 series trucks. For the purposes of this paper, “system” or “system module” refers to an assembly of components that can wholly or substantially perform its design function as a stand-alone unit. An example would be a vehicle seat assembly. A completed seat can perform its intended function sitting on the plant floor, as well as in the vehicle. The impacts of the system module design approach on assembly processing, manufacturing complexity, reliability and quality, and design and validation will be discussed. Various levels of system modularity have been successfully used in recent years in many types of vehicle manufacturing, particularly in the automotive industry.

Workflow automation is a revolutionary technology that dramatically improves office business processes. This paper is a case study of how workflow was introduced into the Truck Design and Technical Center of International Truck and Engine Corporation. Some results and lessons learned are offered.

Effective application of human figure models to truck interior design requires accurate data on the postures and positions of truck drivers. Errors in positioning of figure models propagate to errors in reach, visibility, and other analyses. This paper describes methods used in a recent study to measure in-vehicle driving postures in Class 6, 7, and 8 trucks. A three-dimensional coordinate measurement machine was used to measure body landmark locations after a driver completed a short road course. The data were used to validate posture-prediction models developed in a previous laboratory study. Vehicle calibration, driver selection, and testing methods are reviewed.

Propagation of vehicle interior noise may be discovered through experimental or analytical methods. This study demonstrates a new MATLAB™ application, where detailed acoustic distributions are determined and displayed from limited measurements. In particular, this method renders energy emanating from a commercial truck dash panel. Results show discernable surface details with a blanket contour plot. The contour mesh comprised of linearly-interpolated values from a small number of discrete measurements. Qualitative and quantitative conclusions were easily made from this interpolation, including relative acoustic leakage and radiation concerns - demonstrated by near-field sound intensity.

This paper discusses an analytical tool that has been developed to predict what types of interior sound package treatments may be necessary in a truck cab to meet a predetermined target sound level at the driver location. The steps that were taken to develop this tool involved a combination of experimental measurement and analytical based studies. Measurements were conducted to identify the acoustic strengths of the major noise paths through which sound travels from outside to inside the truck. These findings were then used to develop a sound package that reduced the vehicle interior noise to meet the target. Measurements were primarily made on a chassis roll dynamometer with final road verification to substantiate the dynamometer data. Data obtained from these measurements were also used in the analytical model that predicts the impact of various acoustics parts in the vehicle, and has the capability to optimize the sound package treatment in the vehicle.

International Truck and Engine Corporation introduced a new line of High Performance trucks based on its next generation medium duty platform in February 2001. The new 4000 series that reached full production in April 2001 was the first in a series of models based on this platform to be introduced over the next two years. The new platform will replace all but the heaviest trucks in International's lineup. Even though the primary focus of International's next generation product is addressing the needs of the owners, drivers and maintainers of the truck, the new product is also a key enabler for the execution of International's business strategies of cost and complexity reduction. Integral to the attainment of internal objectives was International's ability to develop products on a common platform to serve across fairly diverse markets.

In this paper, interior noise of a heavy commercial truck was modeled with the room equation. This approach assumed that large truck cabins may be adequately modeled as a practical room as is done in architectural acoustics, where ray theory and statistical concepts are suitable, and where application of complicated wave theory may not be necessary. This simplifies computational requirements, making a semi-empirical scheme useful for timely product development. This study employed sound power measurements at thirty-four surface patches encompassing the interior cabin boundary. Each surface-patch constituted an individual interior noise source. Predicted and measured results correlated well, demonstrating the capability to estimate driver-position noise level from predicted periphery sound intensity changes.