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Technical Paper

Electrochromic Glazings for Use in Automobiles

1996-04-01
91A110
In the present paper we will outline the principles, designs, problems and benefits of electrochromic coatings and present our own laboratory results. The effect of electrochromic coatings on the thermal comfort of a parked vehicle is theoretically calculated and the results confronted with the performances of selective coatings.
Technical Paper

Multifunctional Glasses for Automotive

1996-04-01
91A109
The windows of a vehicle have to satisfy the following driver and passenger needs concerning visibility and climate perception both related to active safety: transparency, reluctance, dazzling, glare and diffused light (scattering). All functions are related to visibility and so to the optics of glazing, solar control, deicing, defogging, demisting. The task of material science is to find the multifunctional glasses solving simultaneously problems of visibility, safety and comfort. Particular kind of glasses, colored, wired, coated, electrochromic, liquid crystal, photochromic can be already considered solutions which can operate passively or actively. The example of passive solar control and active heatable coated glasses is shown as a possible practical multifunctional glass very soon.
Technical Paper

Australian Initiatives in Traffic Management and Energy - Vehicle Parameters and Interactions

1988-03-01
871158
This paper reviews the interactions between vehicle and road designers, particularly in the area of fuel consumption related to traffic management. The need for increased interaction between vehicle and road designers is illustrated in the cases of truck traffic performance, truck technology, information technology in cars, car performance, speed control and road information. Fuel consumption models developed at the Australian Road Research Board are described for the purposes of traffic management analysis for intersections, road links and broad urban studies. These models are a major step towards appropriate choice of traffic control systems, but need accurate estimates of vehicle performance characteristics in real traffic.
Technical Paper

A Non-Averaging Method of Determining the Rheological Properties of Traction Fluids

1999-05-03
1999-01-1518
Traction machines have been frequently used to study the rheological properties of lubricants in elasto-hydrodynamic lubrication (EHL) contacts. Fundamental properties are inferred from EHL traction measurements based on the average pressures and temperatures in the contact. This average approach leads to uncertainty in the accuracy of the results due to the highly nonlinear response of fluid rheological behavior to both pressure and temperature. A non-averaging method is developed in this paper to determine the elastic and plastic properties of traction fluids operating in EHL contacts at small slide-to-roll ratios. A precision line-contact traction rig is used to measure the EHL traction at a given oil temperature and Hertz pressure. By choosing a sensible pressure-property expression, the parameters of the expression can be determined through the initial slope and peak traction coefficient of the traction measurements.
Technical Paper

A New Method for Determining Tire Traction on Ice

2000-05-01
2000-01-1640
The development of tires traction models is very important for tire mechanics and automobile dynamics. Based on principle of thermal balance and theory of frictional melting, a new method for determining tire traction on an iced highway was presented. It was shown that the computed results could compare with the available test results. The advantages of a car with CTI-DS travelling on ice or compact snow were demonstrated in theory and in experiment. It was recommended that an automobile be operating at lower inflation pressures to increase tire traction force on the above highways.
Technical Paper

Improving the Ride & Handling Qualities of a Passenger Car via Modification of its Rear Suspension Mechanism

2000-05-01
2000-01-1630
This paper presents the results of a recent project of IKCo’s research center to modify the Paykan 1600’s rear suspension mechanism with the purpose of improving the car’s comfort, stability and handling qualities. The car was originally equipped with a solid rear axle with leaf springs. By replacing the original mechanism with a three-link mechanism with panhard bar and coil springs, the ride comfort and handling characteristics of the car were noticeably improved.3-D, nonlinear ride and handling models were developed and analyzed to determine the important kinematics and dynamic effects of the new mechanism on vehicle responses. To verify the analytical results, subjective tests were carried out on the vehicle. The results of these tests demonstrated remarkable improvement of the dynamics behavior of the car.
Technical Paper

A Simple and Efficient Description of Car Body Movements for Use in Virtual Prototyping and Ride Comfort Evaluation

2000-05-01
2000-01-1629
Ideally, ride comfort evaluation, or any field evaluating human perception of motion, would be greatly simplified if such evaluation could be made based upon a single number or a simple curve that correlates with the perception of motion. The paper describes a ride comfort descriptor of pitch movements that is simple to use in virtual prototyping and ride comfort evaluations. This descriptor, i.e. Pitch Indicator, is validated in a calculation model, ride comfort measurements and subjective evaluations.
Technical Paper

Motorcycle Suspension Development Using Ride Comfort Analysis with a Laboratory Test System

1999-09-28
1999-01-3276
An analytical approach to developing motorcycle suspensions is presented. Typical uncontrolled and subjective evaluations that place limits on suspension development are curtailed through the use of a laboratory-based road simulation technique, which evaluates vehicle ride quality. Ride comfort is calculated using a specifically tailored NASA model after primary and secondary frequency regimes have been established for this type of motorcycle. Correlation between road and laboratory simulation is measured and compared to the road data variance. A designed experiment evaluates changes in ride quality as a function of suspension and tire pressure adjustments. Various suspension settings are repeated on the simulator and corresponding ride numbers are calculated for both environments. An analysis is performed to correlate ride quality improvements on the simulator with ride quality improvements in the field.
Technical Paper

The Durability and Reliability of Variators for a Dual-cavity Full-toroidal CVT

2000-03-06
2000-01-0826
A full-toroidal CVT has been expected as a new generation of transmission. However, high contact pressure is needed to generate traction force and temperature due to shear in contact areas becomes very high. Therefore, the fatigue life of variator is insufficient. This paper describes the application of developed bearing steel to improve the fatigue life of the varitator. Failure due to pitting depends on a film parameter Λ so that the limitation of Λ to prevent failure has been determined by a two roller test machine. Durability test of the variator made of developed bearing steel with the larger Λ than the limitation has been carried out to confirm the prevention of pitting by a dual-cavity full-toroidal CVT's variator test rig. The thickness of EHD (Elastohydrodynamic) fluid film has also been calculated by isothermal Newtonian EHD analysis with spin motion to confirm whether adequate film thickness is provided to avoid failure.
Technical Paper

Communication and Information Systems - A Comparison of Ideas, Concepts and Products

2000-03-06
2000-01-0810
How can car manufacturers, which are primary mechanical engineers, become software specialists? This is a question of prime importance for car electronics in the future. Modern vehicles offer a large number of electronic and software based functions to achieve a high level of safety, fuel economy, comfort, entertainment and security which are developed under pressure of regulations, of consumers needs and of competitive time to market aspects. This contribution draws a picture, what could be important in future for in car communication and information system in terms of development process, HW & SW architectures, partnerships in automotive industry and security of industrial properties. For this purpose the automotive development is reviewed and actual examples of system designs are given.
Technical Paper

Designing Mobile Air–conditioning Systems to Provide Occupant Comfort

2000-03-06
2000-01-1273
The designer of mobile air–conditioning systems must consider the total vehicle in order to provide occupant comfort. An effective refrigerant circuit is only one portion of the vehicle “Comfort System” and without the system's ability to deliver adequate cooling it will not meet the consumer's expectations. A significant considered is the design of the vehicle's body, including the panel outlets and the extent of window glazing surfaces. The location of the panel outlets to provide the occupant's adequate and controllable system airflow for changing weather conditions is a major factor in achieving comfort. Window glazing locations and areas have a major effect on increasing the air–conditioning thermal load by allowing direct solar radiation into the vehicle. Unfortunately, the styling of the vehicle dictates these areas and these constraints very often result in the customer having an air–conditioning system that provides an unsatisfactory level of performance.
Technical Paper

Numerical Study of the Influence of Air Vent Area and Air Mass Flux on the Thermal Comfort of Car Occupants

2000-03-06
2000-01-0980
In the present paper, first results of an extensive and ongoing parametric study are shown. The objective of the parametric study is to clarify the influence of relevant flow and geometrical parameters on the microclimate and thermal comfort of the occupants. Flow parameters included in the study are air mass fluxes, velocity magnitude, air temperature and inflow direction at the vents. Geometrical parameters of interest are number, location, area and shape of the air vents as well as geometrical details of the passenger compartment itself. The parametric study is performed numerically on the basis of a computational model for a passenger compartment of a Mercedes E-Class sedan. The numerical method used has been published earlier and consists of a system of three programs for simulating the flow and temperature field in the cabin, the heat transfer and radiation and the thermal sensation of the occupants.
Technical Paper

Air Diffusion Concept for Climate Comfort Improvement

2000-03-06
2000-01-0979
Current systems of air diffusion inside the car cabin are leading in some conditions to passenger discomfort. To solve this problem our company has developed a new concept of air diffusion. It consists in an air distribution system composed of a wide central air diffusion area on the top of the instrument panel and two lateral outlets. To evaluate the comfort performances of the concept a methodology based on experiments, simulation and subjective evaluation has been defined and used. The comparison between the current air diffusion and the new one shows a significant impact on the driver's and passenger's comfort. The purpose of this paper is to describe the methodology developed to analyze the air diffusion impact on the comfort and the improvements obtained by the new concept.
Technical Paper

Vehicle Defroster System Evaluation

2000-03-06
2000-01-0984
Vehicle defrost systems are required to defrost the windshield and side windows in a short period. This portion of the HVAC system is not only required to work without interfering with operator comfort relating to high temperatures being felt by the drivers face, but also relating to noise. Add to these restrictions the requirement that the defrost outlets used must be esthetically pleasing, and one can see how much development time is required to design an effective defrost system. Once a design is established, it must be tested. The methods currently used to test defrost performance leaves much to be desired, due to the time required to transpose actual test results into usable data. This transposition includes removing marked tracing from the windows in a cold chamber to trace paper, and then the trace paper needs to be reduced into manageable sizes of paper.
Technical Paper

A Wind Tunnel Investigation of the Transient Aerodynamic Effects on a Four-Car Platoon during Passing Maneuvers

2000-03-06
2000-01-0875
Wind tunnel experiments have been conducted to study the transient aerodynamic forces experienced by the members of a four-car platoon during passing maneuvers with a single vehicle. The drag and side force coefficients on each of the four platoon members are measured simultaneously using strain gauge balances during the maneuver to characterize the transient effects. The results show that every car in the platoon experiences significant changes of drag and side force coefficients when the passing model moves to the proximity of each car. Influences of the lateral spacing and relative velocity between the platoon and the passing model, as well as the shape of the passing model, have also been investigated. Similar trends in force coefficients are observed in both simulation of a vehicle passing a platoon and a platoon overtaking a vehicle.
Technical Paper

Digital Occupant: Personal Immersion for Subjective Evaluations of a Vehicle

2000-06-06
2000-01-2154
Ford’s use of digital mockups in vehicle design has improved the package and fit of components and systems within the vehicle. However, to fully meet and exceed the consumer’s expectations of a vehicle it is crucial to make subjective evaluations of a vehicle’s comfort, convenience, visibility, and accessibility early in the design process. Efficient and nimble design requires an understanding of the subjective qualities of the vehicle before any physical prototypes exist. The Digital Occupant personally immerses an individual (e.g. member of the design team, market researcher or consumer) within the digital mockup earlier to facilitate these subjective evaluations. This paper describes the technologies and emerging methodologies integrated to produce the Digital Occupant. This personally immersive simulation includes a full body real-time dynamic digital representation of the individual being immersed.
Technical Paper

Influence of Forces on Comfort Feeling in Vehicles

2000-06-06
2000-01-2171
When investigating the posture comfort in vehicles two important influencing factors can be distinguished: In order to evaluate these influences a combined laboratory-field-experiment was carried out. A real car was equipped with cameras to record the body posture and the joint angles. The static forces exerted by the driver on his contact points were recorded in a corresponding mock-up. The forces to maintain the body posture were calculated. The following results were found:
Technical Paper

Ergonomic Evaluation of an Aircraft Cockpit with RAMSIS 3D Human Modeling Software

2001-06-26
2001-01-2115
The 3D digital human model RAMSIS, which is primarily used in the automotive industry, has been used to predict probable pilot behavior in a proposed cockpit design for the Eclipse 500 jet. The results were used to detect potential accommodation problems as early as possible, as well as to establish guidelines and requirements for further design of the cockpit and interior components. Defining interactions between a digital human model and a CAD environment, such that it reflects interaction between real pilots and cockpits as realistically as possible, is often an arbitrary process. Nevertheless, 3D human models prove to be powerful design tools for aircraft cockpit designers to ensure functional and comfortable accommodation of the target pilot population.
Technical Paper

Ergonomic Evaluation and Visualization in the Car Design Process

2001-06-26
2001-01-2114
Industries strive to minimize their development costs, to shorten the time required for development and to increase the quality of the product. The paper summarizes three ergonomic evaluation methods developed for the automotive industry. The first method presents a manikin with a movement pattern similar to people. The second method is a tool to evaluate comfort that can be combined with a manikin. The third and last, is a methodology for eliciting user comments. Ergonomic evaluation methods and tests with a computer support and generate information that may lead to reduced product development cost. These kinds of tools are also suitably used in cross-functional project groups in order to visualize alternative designs, and evaluations in a participative process. Visualization of traffic, driver and eye-movements seems to open up the discussion and is a step to a more user-centered design process.
Technical Paper

Modeling of Human Thermal Comfort

2001-06-26
2001-01-2117
Current vehicle climate control systems are dramatically overpowered because they are designed to condition the cabin air mass in a specified period of time. A more effective and energy efficient objective is to directly achieve thermal comfort of the passengers. NREL is developing numerical and experimental tools to predict human thermal comfort in non-uniform transient thermal environments. These tools include a finite element model of human thermal physiology, a psychological model that predicts both local and global thermal comfort, and a high spatial resolution sweating thermal manikin for testing in actual vehicles.
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