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Computational Fluid Dynamics (CFD) is used in this investigation to determine the velocity field in the vicinity of vehicle windshield due to defroster flow. The analysis was performed using the CFD package STAR-CD. CFD results were obtained and compared to test data. Hot-wire anemometry was used to experimentally determine the velocity field in the vicinity of the defroster nozzle jet flow and windshield interior surface. The experimental results were used to verify the integrity of the CFD models and validate our use of CFD modeling. The ability of the CFD models to quantify the flow field can be inferred from the present results. Based on the degree of correlation of the velocity profiles between the CFD simulations and the experimental work, it can be concluded that CFD simulation is a valid technique to investigate the air flow characteristics of vehicle defroster and windshield flow field.

In this paper, functional analysis is employed to develop an ideal path of a vehicle undergoing a limit lane-change maneuver. Inputs to the problem are the lane width, tire-road coefficient of friction and either vehicle velocity or total longitudinal lane-change distance. Vehicle velocity is assumed to be constant. The problem is formulated using the calculus of variations. The solution technique relies on elliptic functions to achieve a closed-form solution. The synthesis of an ideal lane-change trajectory is treated as a minimal-energy-curve optimization problem with prescribed continuity and boundary conditions. The concept of critical speed is employed to limit the maximum curvature of any specified lane-change, thereby ensuring that the synthesized trajectory function describes a path that can be traversed under realistic road conditions. The analytical solution is confirmed by comparison to a numerical solution and a validated 8 degree-of-freedom vehicle model simulation.

This paper will explain the C5 Corvette Active Handling (AH) control strategy formulated around the base vehicle characteristics and additional integrated components. The new chassis control strategy uses electrohydraulic brake pressure at all four corners to input braking forces independent of the driver. AH was designed to assist the driver in controlling the vehicle during limit handling situations. The primary inputs to the chassis control strategy are vehicle speed, steering wheel angle, yaw rate about a vertical axis passing through the vehicle's c.g., brake pressure and lateral acceleration. Vehicle ride demonstrations and vehicle modeling were used to show the benefit of Active Handling.

This paper presents a computationally efficient tire model developed for real-time simulation that produces functionally correct behavior over a wide variety of operating conditions. The fidelity must be sufficient to support validation of antilock brakes, traction control and chassis control systems. The model is based on an idealized physical representation of the tire. It decomposes the tire-road characteristics into a point model of the contact patch, coupled to the wheel through radial, longitudinal, and lateral stiffness and damping. Sliding at the contact point between the tire and road is determined using the friction circle approach. Lateral and longitudinal coefficients of friction are based on the sliding velocity. The apparent slip, both lateral and longitudinal, of the tire as it rolls is a direct result of the state of deformation of the tire, and is characterized by relaxation parameters. Deformation state variables also provide the transient response of tire forces.

The prevalence of microprocessor-based controllers in automotive systems has greatly increased the need for tools which can be used to validate and test control systems over their full range of operation. The objective of this paper is to develop a real time simulator of an anti-lock brake system and the methodology of using hardware-in-the-loop simulation based on a personal computer. By use of this simulator, the analyses of a commercial electronic control unit as well as the validation of the developed control logics for ABS were performed successfully. The simulator of this research can be applied to the development of more advanced control systems, such as traction control system, vehicle dynamic control system and so forth.

Rapid and effective windshield defrosting has been the goal of various investigations by automotive engineers around the world. Car manufacturers have invested considerable resources to satisfy the thermal needs, safety requirements, and comfort demands of their customers. This paper addresses the climate control issues of defrosting automotive windshields. The paper summarizes the state of knowledge of the various approaches for improving defroster performance. Experimental as well as computational efforts, accompanied by heating techniques and heat boosters will be presented. The paper also features relevant measurement methods for airflow and thermal patterns, and discusses current challenges. Recommendations are made on where to focus engineering and design efforts given the state of present technologies.

In conventional powder metallurgy (P/M), structural stainless steel parts are produced by pressing alloy powder of the appropriate composition in a die to produce a compact. The compact is then sintered at an elevated temperature in a controlled atmosphere, bonding the particles together by diffusion and densifying the part. In this paper the P/M process is reviewed and its capabilities are discussed. Following this, the more common stainless steel compositions are detailed and the advantages of the P/M process are summarized.

A low-cost approach for experimenting using numerical methods, including finite element analysis (FEA), is presented. The method is illustrated by its application to the design of a D-shaped shaft. A reduction of >23% in stress is achieved compared with an “educated guess” design. Commonly used experimental techniques including Taguchi methods require many unneeded runs when applied to numerical methods. They also make insupportable assumptions about interactions being zero, not allowing the user to fit commonly used non-linear models. We describe how our method with 36 runs is likely to give better results than Taguchi methods using 162 runs.

This paper investigates an approach to minimize the mass imbalance excitation of an automotive HVAC blower system through the control of the blower fan dynamic imbalance. The total mass imbalance of a blower fan, known as the fan static imbalance, is resolved into two plane dynamic imbalances. A theoretical analysis relates the magnitude of each plane imbalance and the phase angle between the two plane imbalances, is included. The vibration spectra of the imbalance design of experiment DOE runs, in the radial and axial directions, with respect to the blower motor shaft, are recorded. The data are analyzed by linear and second order statistic models, the results and contour plots of peak vibration levels versus the two plane imbalance are described. The interaction between the resultant imbalance of a blower fan and the that of its driving motor is studied to reveal a noise factor in the DOE.

Forged bearing steels and powder forged steels (e.g. AISI 52100, SAE 5160 and MPIF FL-4680) have been used to make cam lobes for assembled camshafts operating with roller followers. Application of powder metal (pressed and sintered) alloys to this and other components that operate under high rolling contact stress has been limited by relatively poor rolling contact fatigue (RCF) properties. This paper introduces developmental sintered steel alloys with high RCF strength. The density of these alloys is 7.4-7.6 Mg/m3 and the macrohardness is 500-800 HV. Endurance limits are in the range 1,700-2,280 MPa. The RCF endurance limit at 200 million stress cycles was determined using a testing rig. Camshafts for a 4.6 L V8 engine and a 4.0 L V6 engine have been assembled. These engines have a single overhead camshaft with end pivot rocker with roller follower (type 2 valve-train).

A new 12.5 L four-valve heavy duty diesel engine has demonstrated that Powdered Metal (PM) is an effective material alternative to wrought steel for the valve bridge. The valve bridge, an element that spans the pair of intake or exhaust valves, allows a single rocker arm to actuate the pair of valves. The component is subjected to a high number of cycles at a moderately high load and geometry precision is essential for desirable wear characteristics. The PM material selected, MPIF FL4605-120HT, has replaced 8620 steel after making component geometry changes. The PM part has a higher load capacity than the original design with equivalent wear characteristics and offers a 80% cost saving over the original design. This paper presents the geometry changes defined by FEA analysis and component testing performed to verify the change from wrought steel to PM. A required characteristic of this component is moderately high fatigue strength.

High density is well known to improve both mechanical and magnetic properties. The limited number of applications of PM in automotive starters was mainly due to low cost target not compatible with the obtention of the needed density. This paper will present two successful developments in that field: a starter gear and a magnetic pole. In both cases, the use of SPSS process in cold conditions has allowed the establishment of the cost target. The magnetic pole is produced in pure iron, pressed at a density of 7.50 g/cm3 and sintered at 1120 °C. The starter gear needed high density and high hardness, associated to high toughness (resistance to pitting but also shock resistance). The paper will describe how a density of 7.65 g/cm3 was achieved in cold condition after pressing / sintering / sizing leading to hardness of 62 HRC after case hardening. Dimensional properties at that density level will be also presented and discussed.

P/M soft magnetic materials represent a substantial and rapidly growing segment of advanced particulate materials used to produce high performance automotive components. In addition, new automotive engineering designs often require improved magnetic characteristics, typically beyond the capabilities of the most widely used P/M materials for soft magnetic applications. The influence of modified chemical composition and processing parameters on the soft magnetic properties of several common P/M soft magnetic materials are discussed. The soft magnetic properties obtained from these experiments are presented and discussed relative to higher performance requirements of the end users.

Light distributions of headlamps have a large influence on the areas of fixation of drivers at nighttime. Physiologigal factors of the perception cause a fixation in bright areas in the field of vision. The illumination of the road scene and therewith the luminance of the road and the objects is depending on the light distribution of the headlamp. The paper shows the influence of typical light distributions of different types of headlamps on the visual strategy of drivers. It trys to answer the question “Is it possible to influence the drivers field of viewing?” In a second part it deals with the question of the influence on the driving behaviour and the safety feeling of drivers.

Although we have measured the luminance of visual circumstances like road surface, lane-mark, traffic sign, etc., by using luminance meters. It took us a lot of operating time to grasp spread of all visual circumstances. Under the circumstances varied with the time such as fog, rain and so on, it is impossible to measure at many points on a definite condition. In this report, we would present our development of the new system and its real application to visual circumstances, in which a lot of brilliance can be measured at the same time by the transaction of portrait of digital still camera.

As competitive pressures grow in the automobile market, the reciprocal influences exerted between rearlamp styling trends and ever-more rapid developments in design and production techniques are increasingly important. After an examination of the mechanisms which by which Styling and Engineering both drive and emulate each other, we will deal with probable future developments.

Vehicle wind noise testing is usually done at elaborate tunnel facilities with minimal tunnel background noise, Techniques to reduce the tunnel noise, such as acoustic panels or improved fan systems, translate into higher costs for wind noise testing. We introduce an innovative procedure using an adaptive filtering algorithm to separate the tunnel noise from the wind noise inside the cabin of the vehicle. This new technique is capable of artificially reducing the tunnel background noise at low frequencies. Such a procedure has the potential to dramatically improve the wind noise testing capability of any wind tunnel, without the need for costly acoustic treatments.

Neon light sources offer unique challenges to the optical design of automotive lighting. When the tubular neon light source was first introduced, its luminous intensity distribution was assumed to be the same as other tubular sources, such as fluorescent tubes. However, upon investigation and analysis of measured data it became apparent that unlike fluorescents, neon tubes, as a volume source, provide a unique luminous intensity distribution instead of the familiar Lambertian distribution. This paper will develop an optical model for a tubular volume light source (neon tube), and further results will identify the effects of other optical elements, such as fluted lensing.

There is a continuing debate in the scientific literature and among policy making bodies regarding the role of roof crush in the causation of rollover accident injuries. A question arising from field studies is whether the correlation between roof crush and injuries occurs because roof crush causes injuries or because roof crush is associated with accident severity, which is related to injury potential. Recent literature is reviewed to address this question. The Malibu rollover tests have been criticized for the level of “potentially injurious impacts” measured in the Hybrid III dummies used in these studies. Additionally, it has been asserted that the Hybrid III neck is excessively stiff in compression and that experimental testing with the Hybrid III produces results that are not representative of human occupant responses.

The aerodynamic forces induced on a generic ‘hatchback’ model have been measured as it passes through a perpendicular cross-wind jet generating a relative yaw angle of 30°. This has been done in the unique University of Durham automotive wind tunnel, which utilises the stationary model approach, with the cross-wind being introduced by means of a second jet which is separated from the main jet by a moving belt and aperture assembly. Data acquisition was by means of an array of surface pressure tappings. Transient pressure force and moment coefficients have been measured and it is shown that the side and lift forces experienced in the transient situation exceed the steady state values at corresponding yaw angles by between 10% and 20%.