Showing papers in "SAE transactions in 2001"

Advanced Aerodynamic Devices to Improve the Performance, Economics, Handling and Safety of Heavy Vehicles

Abstract: Research is being conducted at the Georgia Tech Research Institute (GTRI) to develop advanced aerodynamic devices to improve the performance, economics, stability, handling and safety of operation of Heavy Vehicles by using previously-developed and flight-tested pneumatic (blown) aircraft technology. Recent wind-tunnel investigations of a generic Heavy Vehicle model with blowing slots on both the leading and trailing edges of the trailer have been conducted under contract to the DOE Office of Heavy Vehicle Technologies. These experimental results show overall aerodynamic drag reductions on the Pneumatic Heavy Vehicle of 50% using only 1 psig blowing pressure in the plenums, and over 80% drag reductions if additional blowing air were available. Additionally, an increase in drag force for braking was confirmed by blowing different slots. Lift coefficient was increased for rolling resistance reduction by blowing only the top slot, while downforce was produced for traction increase by blowing only the bottom. Also, side force and yawing moment were generated on either side of the vehicle, and directional stability was restored by blowing the appropriate side slot. These experimental results and the predicted full-scale payoffs are presented in this paper, as is a discussion of additional applications to conventional commercial autos, buses, motor homes, and Sport Utility Vehicles.

The effect of metallurgical variables on the machinability of compacted graphite iron

Abstract: The influence of graphite shape, pearlite content and chemical composition have been investigated to determine their effect on the machinability of compacted graphite iron (CGI) . In the comparison to gray iron, the reduced sulfur content of CGI prevents the beneficial formation of a protective manganese sulfide layer on the cutting insert. This accounts for much of the difference in tool life during high speed continuous cutting. Beyond this critical mechanism, the machinability of CGI can be optimized by providing a consistent, low nodularity microstructure with a minimum of tramp elements such as titanium and chromium that form abrasive inclusions.

A Preliminary Study of Energy Recovery in Vehicles by Using Regenerative Magnetic Shock Absorbers

Abstract: Road vehicles can expend a significant amount of energy in undesirable vertical motions that are induced by road bumps, and much of that is dissipated in conventional shock absorbers as they dampen the vertical motions. Presented in this paper are some of the results of a study aimed at determining the effectiveness of efficiently transforming that energy into electrical power by using optimally designed regenerative electromagnetic shock absorbers. In turn, the electrical power can be used to recharge batteries or other efficient energy storage devices (e.g., flywheels) rather than be dissipated. The results of the study are encouraging - they suggest that a significant amount of the vertical motion energy can be recovered and stored.

Dynamic interactions between loaded and unloaded gear pairs under rattle conditions

Abstract: In many manual transmissions, conditions for the onset of vibro-impacts from an unloaded gear pair are more likely than from an engaged set. Although some of the general characteristics of neutral gear rattle are known, no specific analytical models are available in the literature that can explain interactions between unloaded and loaded gear pairs in the drive rattle mode. For the sake of illustration, a particular problem for a light duty truck is studied in this paper and dynamic interactions are investigated. Some experimental measurements are first presented to define the unloaded gear rattle problem. Linear and non-linear mathematical models of the driveline are developed to understand, quantify and control the rattle problem. Trends predicted by simulations are compared with those observed in experiments. The effects of various gear run-ups and vibratory drag torques are investigated.

A Case Study in Applying a Product Line Approach for Car Periphery Supervision Systems

Abstract: Car Periphery Supervision (CPS) systems comprise a family of automotive systems that are based on sensors installed around the vehicle to monitor its environment. The measurement and evaluation of sensor data enables the realization of several kinds of higher level applications such as parking assistance or blind spot detection. Although a lot of similarity can be identified among CPS applications, these systems are traditionally built separately. Usually, each single system is built with its own electronic control unit, and it is likely that the application software is bound to the controller’s hardware. Current systems engineering therefore often leads to a large number of inflexible, dedicated systems in the automobile that together consume a large amount of power, weight, and installation space and produce high manufacturing and maintenance costs. This paper reports on an initiative undertaken by the Bosch Group in applying a product line development approach to develop CPS systems economically. Product line development represents a multi-system engineering approach which takes common and variable aspects between systems in the same application domain into account. It provides a basis to develop a line of products economically based on a common system architecture and reusable components. A product line allows the degree of reusability to be optimized across different systems while simultaneously preserving the overall quality. This supports the need to develop more integrated and flexible multi-functional systems quickly and cost-effectively. The purpose of this paper is to report on the experiences and results obtained from a case study in developing a product line of CPS systems.

Effect of solar reflective glazing on ford explorer climate control, fuel economy, and emissions

Abstract: The energy used to air condition an automobile has a significant effect on vehicle fuel economy and tailpipe emissions. If a small reduction in energy use can be applied to many vehicles, the impact on national fuel consumption could be significant. The SCO3 is a new emissions test conducted with the air conditioner (A/C) operating that is part of the Supplemental Federal Test Procedure (SFTP). With the 100% phase-in of the SFTP in 2004 for passenger cars and light light-duty trucks, there is additional motivation to reduce the size of the A/C system. The U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) is investigating ways to reduce the amount of energy consumed for automobile climate control. If the peak soak temperature in an automobile can be reduced, the power consumed by the air conditioner may be decreased while passenger comfort is maintained or enhanced. Solar reflective glass is one way to reduce the peak soak temperature. NREL and PPG Industries conducted a test program with Sungate laminated solar reflective glass installed in a Ford Explorer to quantify improvements in fuel economy and reductions in tailpipe emissions. Test results showed a dramatic reduction in interior and glass temperatures. After the A/C system and its effect on the passenger compartment were modeled to assess the potential reduction in compressor power, the vehicle performance was predicted.

Using Cluster Analysis for Deriving Menu Structures for Automotive Mobile Multimedia Applications

Abstract: This paper describes the cluster analysis technique and how it can be used to support menu interface design for in-vehicle multimedia applications. Cluster analysis and similar types of classifying techniques have proven effective for developing simple menu interfaces. This paper extends the use of the cluster analysis technique to a more complex system that consists of 201 generic functions. These functions are representative of those being incorporated into near-term multimedia products. Study results show promise for using cluster analysis as a tool for incorporating the user’s organizational structure into the design of a complex menu architecture. Cluster analysis may also benefit the automotive menu designer by providing a means for partitioning menu tasks into chunkable units that can be easily accessed by the driver in single glances.

Towards Understanding the Workspace of the Upper Extremities

Abstract: Significant attention in recent years has been given towards obtaining a better understanding of human joint ranges, measurement, and functionality, especially in conjunction with commands issued by the central nervous system. Studies of those commands often include computer algorithms to describe path trajectories. These are typically in \" open-form \" with specific descriptions of motions, but not \" closed form \" mathematical solutions of the full range of possibilities. This paper proposes a rigorous \" closed form \" kinematic formulation to model human limbs, understand their workspace, and delineate barriers therein where a path becomes difficult or impossible owing to physical constraints. The novel ability to visualize barriers in the workspace emphasizes the power of these closed form equations. Moreover, this formulation takes into account joint limits in terms of ranges of motion. Examples include the workspaces of a typical forearm, a typical finger, and is used to illustrate the visualization of the progress in the functionality of a wrist undergoing rehabilitation.

Design of an Advanced Heavy Tactical Truck: A Target Cascading Case Study

Abstract: The target cascading methodology is applied to the conceptual design of an advanced heavy tactical truck. Two levels are defined: an integrated truck model is represented at the top (vehicle) level and four independent suspension arms are represented at the lower (system) level. Necessary analysis models are developed, and design problems are formulated and solved iteratively at both levels. Hence, vehicle design variables and system specifications are determined in a consistent manner. Two different target sets and two different propulsion systems are considered. Trade-offs between conflicting targets are identified. It is demonstrated that target cascading can be useful in avoiding costly design iterations late in the product development process.

Gender and age influence on fatality risk from the same physical impact determined using two-car crashes

Abstract: In the study presented in this scientific poster crashes between single occupant cars, one driven by a female and the other by a male, were selected from the Fatality Analysis Reporting System (FARS). The analysis establishes that females are more likely to die than males for ages from 20 to about 35, corrobating the higher precision results of an earlier study. The analysis also shows that the male and female fatality risk increases with increasing age are consistent with the higher precision results of the earlier studies using unrelated methods and data. The relatively close quantitative agreement between estimates using unrelated methods and non-overlapping data provides additional support for the interpreretation that each study is measuring fundamental differences in human response to blunt trauma insults. The agreement further solidifies the essential validity of each of the conceptually unrelated methods. For the covering abstract of the conference see ITRD E203784.