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Vehicle sound quality has become an important basic performance requirement. Traditionally, automobile noise studies were focused on quietness. It is now necessary for the automobile to be more than quiet. The sound must be pleasing. This paper describes a development process to improve both vehicle noise level and sound quality. Formal experimental design techniques were utilized to quantify various hardware effects. A-weighted sound pressure level, Speech Intelligibility, and Composite Rating of Preference were the three descriptors used to characterize the vehicle's sound quality. Engineering knowledge augmented with graphical and statistical techniques were utilized during data analysis. The individual component contributions to each of the sound quality descriptors were also quantified in this study.

A new method to predict brake squeal occurrence was developed by MSC under contract to Ford Motor Company. The results indicate that the stability characteristics of this disc brake assembly are governed mainly by the frictional properties between the pads and rotor. The stability is achieved when the friction coefficient of the pads is decreasing as the contact force increases. Based on the results, a stable brake system can be obtained without changing the brake structure by incorporating the appropriate frictional coefficient in the brake system. The method developed here can be also used as a tool to test the quality of any brake design in the early design stage.

This paper presents a new transient passenger thermal comfort model. The model uses as inputs the vehicle environmental variables: air temperature, air velocity, relative humidity and mean radiant temperature all of which can vary as a function of time and space. The model also uses as inputs the clothing level and the initial physiological state of the body. The model then predicts as a function of time the physiological state of the body and an effective human thermal sensation response (e.g. cold, comfort, hot, etc.). The advantage of this model is that it can accurately predict the human thermal sensation response during transient vehicle warm-up and cooldown conditions. It also allows design engineers the ability to conduct parametric studies of climate control systems before hardware is available. Here we present the basis of the new thermal comfort model and its predictions for transient warm-up and cooldown conditions.

In this study, we present an intelligent and wireless subsystem for powering and communicating with three sets of seat belt buckle sensors that are each installed on removable and interchangeable automobile seating. As automobile intelligence systems advance, a logical step is for the driver’s dashboard to display seat belt buckle indicators for rear seating in addition to the front seating. The problem encountered is that removable and interchangeable automobile seating outfitted with wired power and data links are inherently less reliable than rigidly fixed seating, as there is a risk of damage to the detachable power and data connectors throughout end-user seating removal/re-installation cycles.

Ribbed floor panels have been widely applied in vehicle body structures to reduce interior noise. The conventional approach to evaluate ribbed floor panel designs is to compare natural frequencies and local stiffness. However, this approach may not result in the desired outcome of the reduction in radiated noise. Designing a “quiet” floor panel requires minimizing the total radiated noise resulting from vibration of the floor panel. In this study, the objective of ribbed floor panel design is to reduce the total radiated sound power by optimizing the rib patterns. A parametric study was conducted first to understand the effects of rib design parameters such as rib height, width, orientation, and density. Next, a finite element model of a simplified body structure with ribbed floor panel was built and analyzed. The structural vibration profile was generated using MSCINastran, and integrated with the acoustic boundary element model.

To serve the need of in-line rear axle diagnostics as well as other types of transmission inspection, an angular sensor development has been undertaken. It has resulted in a new device, incorporated into a system which performs angular error sensing at three levels. High precision of better than 0.003% in velocity variations is achieved. A continuous check of the null-error status of the devices is maintained in order to ensure maximum reliability of the readings. An easy on-site calibration check is available which eliminates the need for any precision calibrating fixture. The device is configured to accommodate a pass-through drive shaft for in-line mounting. A rugged design and immunity to rotor imperfections are advantageous in a plant environment.

The technique of evaporating fuel by localized heating before entering the intake manifold is evaluated as a means of improving A/F ratio control. Techniques currently in use are briefly discussed, and attempts to analyze fuel evaporation in S.I. engines are reviewed. A test fixture which includes all the essential features of production feasible hardware is used to develop a basis of understanding for the evaporation process. Tests are conducted on a flow bench using water as “fuel”, and on an engine using isooctane and gasoline. A heat-mass transfer analogy is described and used to predict evaporation rates for water and isooctane. Predicted and measured rates are compared for both bench and engine tests. Engine tests with gasoline show the ability of the test configuration to evaporate all part throttle fuel flow before it enters the intake manifold.

For many years, carmakers have developed unique system designs to gain a competitive advantage using some unique technology or an optimization of a design to cut costs or improve quality. This leads to continual increase in complexity, long development times and high development costs. A common platform, based on an "open architecture,'' provides a solution for many of the problems associated with the conventional automotive approach to electrical/electronic system designs. The PC industry is a prime example of how an open architecture can provide benefits to the consumer, manufacturers of software and hardware components, as well as complete system integrators. The PC, based on the initial IBM computer developed in the early eighties, has become a de facto standard that has survived 20 years of fast and dramatic changes in the fundamental technologies used within the platform.

Sliding door designs are applied to rear side doors on vans and other large vehicles with a trend towards dual sliding doors with power operation. It is beneficial for the vehicle user to reduce the weight of and space occupied by these doors. Alcoa, in conjunction with Ford, has developed a multi-product, multi-material-based solution, which significantly reduces the cost of an aluminum sliding door and provides both consumer delight and stamping-assembly plant benefits. The design was successfully demonstrated through a concept readiness/technology demonstration program.

Recent investigations by others have indicated that the dynamic response of automotive brake rotors in the squeal frequency range involves the classic flexural modes as well as in-plane motion. While the latter set creates primarily in-plane displacements, there is coupling to transverse displacements that might produce vibrational instabilities. This question is investigated here by analyzing a modal model that includes two modes of the rotor and two modes of the pad and caliper assembly. Coupling between in-plane and transverse displacements is explicitly controlled. Results from this model indicate that the coupling does create vibrational instabilities. The instabilities, whose frequencies are in the squeal range, are characterized by power flow through the transverse motion of the rotor.

Automatic headway control is an evolutionary step towards an automatic vehicle guidance and control system. This system expands the capability of the currently available production option-speed control. This paper describes the system from a theoretical and hardware viewpoint, with emphasis on the control logic. The electronic and electromechanical hardware design based on the theory presented is fully described. The limitations and advantages of the system are explained, based on test results from actual trial runs on an implemented vehicle. Capacity and safety benefits are made somewhat tangible by direct comparison with test results obtained on a roadway similar to that for which this system is recommended, under test conditions directly analogous to the operating characteristics of the automatic headway control system.

Side impact collisions account for about 29% of all vehicle occupant fatalities and for about one-fifth of all the “harm” to vehicle occupants. This paper addresses many aspects of side impact induced injuries which vehicle planners and designers may choose to consider during the evolution of a vehicle design. The proposed NHTSA side impact test, side impact dummies, the biomechanics of different human body areas and general concepts for increased occupant protection are discussed from a theoretical point of view. It is believed that this paper or a future update of it, can only become a useful tool when there is general agreement that it reflects solid biomechanical direction which in turn, can be reflected in actual, practicable, responsible hardware design.

For purposes of reducing development time, cost and risk, the majority of new vehicles are derived strongly or at least generally from a surrogate vehicle, often of the same general size or body style. Previous test data and lessons learned can be applied as a starting point for design of the new vehicle, especially at early phases of the design before definite design decisions have been finalized and before prototype of production test hardware is available. This is true as well of vehicle NVH development where most new vehicles being developed are variants of existing vehicles for which the main noise transfer paths from sources of interest are already understood via test results and existing targets. The NVH targets for new vehicles are defined via benchmarking, market considerations, and other higher-level decisions. The objective is then to bridge the gap between test data from surrogate vehicles to direct support of the NVH development of new vehicle programs.

This paper proposes to utilize the Automobiles Entertainment Audio and Cellular Phone Systems as an information terminal to access the Information Super Highway better known as the WorldWide Web. As society moves to an ever increasing information based technology, there will be an ever expanding need to provide new ways and means of allowing access to the data on the WorldWide Web and Internet from many various locations and at a variety of different times. The authors recognize that rather large amounts of data and research have conducted and presented relative to obtaining information from and across the WorldWide Web. Additionally much work has been expended in the development of enhanced Driver Information Systems within the Automotive Industry.

This paper describes a test-based process used to identify structural characteristics of a vehicle windshield wiper system that contribute to customer impression of the sound. The method of paired comparisons determined which wiper system sounds customers preferred. Annoyance ratings of sound components then identified contributors to customer preference. Wiper motor noise was identified as the major annoyance factor affecting system sound quality. This information guided a study of the structures responsible for radiated motor noise. Laser based test methods were used to interrogate the structures clearly identifying transmission paths into the surrounding structure. Paths were then modified reducing structure-borne motor sound as measured with acoustic retests. Thus, a logical technique for hardware testing and modification guided by customer perceptions is presented allowing efforts to be focussed on the most critical aspects of vehicle sound quality.

The idea of using a single electrical machine for both starting the engine and generating electrical power is not new. However, the real benefits, that justify the higher cost of a combined starter-alternator, become apparent when it is used as part of a hybrid powerplant. This powerplant allows a substantial improvement in fuel economy by a variety of methods (i.e. the engine shut-down during deceleration and idle, regenerative braking, etc.), as well as enhancements to engine performance, emissions, and vehicle driveability. This paper describes the analysis of the structure supporting the starter-alternator on the end of the engine crankshaft (Figure 1). It deals with the requirement to maintain a small radial gap between the rotor and stator, and it discusses how the rotor affects the loading on the crankshaft. In addition, thermal deformations of the rotor/clutch assembly are analyzed with three light-weight materials.

Friction behavior is one of the most critical factors in brake system design and performance. For up-front design and system modeling it is desirable to be able to describe a lining's frictional behavior as a function of the local conditions, such as contact pressure, temperature and sliding speed. Typically, frictional performance is assessed using brake dynamometer testing of full-scale hardware, and an average friction value is used during brake system development. This traditional approach yields an average brake friction coefficient that is hardware-dependent and fails to capture in-stop friction variation; it is also unavailable in advance of component testing, ruling out true up-front design and prediction. To address these shortcomings, a scaled inertial brake dynamometer was used to determine the frictional characteristics of candidate lining materials.

There is an ever increasing demand on part quality and tighter tolerances for machining of components in high volume manufacturing. A major source of problem in the machine tools is the thermally induced error due to thermal gradients and uneven heating and expansion of various machine components. Current practice of manufacturing precision parts involves periodic gaging of parts, whereby, production is interrupted and manual compensating offsets are input to the controller. Also, additional production costs are introduced due to requirement of initial warm up cycles without cutting parts and utilization of chillers for temperature controlled coolants. In this paper, a methodology is described for automatic compensation for thermal error by means of components/locations temperature profile and calculated error between the tool tip and the workpiece.

Turbocharged gasoline engines are typically equipped with a compressor anti-surge valve or CBV (compressor by-pass valve). The purpose of this valve is to release pressurized air between the throttle and the compressor outlet during tip-out maneuvers. At normal operating conditions, the CBV is closed. There are two major CBV mounting configurations. One is to mount the CBV on the AIS system. The other is to mount the CBV directly on the compressor housing, which is called an integrated CBV. For an integrated CBV, at normal operating conditions, it is closed and the enclosed passageway between high pressure side and low pressure side forms a “side-branch” in the compressor inlet side (Figure 12). The cavity modes associated with this “side-branch” could be excited by shear layer flow and result in narrow band flow noises.

Real-time pressure measurement inside sealed electrical connectors has been achieved using a new experimental approach. This approach has significant benefits to designers of connectors and the seals used to waterproof the connectors. The seal designer needs to know what pressure is in the connector but until now, pressure measurements were inaccurate due to the slow response time of the equipment. The result was that a peak in pressure of less than 1 second duration would be not recorded. This lack of accurate pressure data has resulted in overdesigned seal plugs - to compensate for the unknowns in testing - and potentially connectors that do not seal as well as required. With the new experimental technique described in this paper, data sampling rates have been increased to 100 samples per second with high accuracy. The new technique uses a portable micro pressure transducer that has been repackaged to fit where a connector wire normally fits.