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Technical Paper

A New Look at the Service Life Expectancy of Passenger Cars in the United States

An estimate of the rate of attrition of passenger cars, needed to establish the service life expectancy of passenger cars, is of major interest whenever long range production plans are made, marketing strategies are developed, the total needs of vehicles on the roads are estimated, etc. Estimation of vehicle attrition is very complex, however, due to the lack of accurate data and the interaction of the parameters affecting attrition. In 1980 and 1985, similar studies of attrition [1,2] utilized vehicle registration data available as of July, 1979 and as of July, 1984. The object of this paper is to update the results of these papers, using the 1991 July registration data, available in May 1992. Within the scope of this paper the attrition rates of various passenger cars are compared and the effect of geographical location on the attrition rates and the change in attrition rates during the past twenty years are discussed.
Technical Paper

ACT - Ford's Automatically Controlled Transportation System

This paper contains a technical description of the Ford Motor Co.'s ACT system which has been designed to meet transportation needs in a wide variety of urban applications. The discussion covers the systems design features and operation of the driverless rubber-tired vehicles, the guideway, and the system's ability to meet expanding needs by a modular approach to the command and control design. Descriptions of Ford's new Cherry Hill Test Track and the first installations at the Fairlane Town Center in Dearborn, Mich., and the Bradley International Airport, Hartford, Conn., are also presented.
Technical Paper

Accurate Modeling for the Powertrain and Subframe Modes

Powertrain mounts are one of the important design characteristics of a vehicle. Powertrain is mostly mounted to the front subframe and once installed in a vehicle, powertrain mounting has an important role in determining the vehicle vibration characteristics. A good mounting system isolates engine input vibration from the vehicle body and minimizes the effect of road inputs to the customer. This paper discusses results of several dynamic models as they relate to noise, vibration and harshness (NVH) and compares the accuracy of these models. Various powertrain models are studied and their accuracy in comparison with full a vehicle model is discussed.
Technical Paper

An Approach for Highway Transportation Systems Research — A Model and Instrumentation

This paper outlines an approach to highway transportation research which considers the interrelationship of the major subsystems. It describes the framework, the variables, surveillance techniques, and new vehicle instrumentation. A model is described which serves as the basis for field testing and subsequent mathematical analyses. Surveillance systems including instrumented vehicles, ground, aerial, and space platforms are required as components of a real-time system. A research project, designed to evaluate driver stress, is discussed and sample computer data are shown.
Technical Paper

An Objective Approach to Highway Truck Frame Design

The design requirements for the frame as a load carrying member are discussed in relationship to a highway truck and its basic vehicle package. The theoretical and experimental procedures are given in detail to demonstrate the techniques for frame design. The features of a method to laboratory test a frame with correlation to service miles is discussed.
Technical Paper

Application of Random Vibration Test Methods for Automotive Subsystems Using Power Spectral Density (PSD)

The object of this paper is to develop a random vibration laboratory test specification for automotive subsystems using the Power Spectral Density (PSD) method. This development is based on the 150k mile field data collected from vehicle proving grounds. The simulated vibration bench test will be used to simulate the energy of the 150k mile field data. The developed specification will include 3 axis random vibration profiles of appropriate duration. The Power Spectral Density method converts the time-domain field data into the frequency-domain data. The Enveloped Energy method groups the similar road PSD profiles to produce a generic PSD profile. The Inverse Law allocates an adjusted duration to the desired PSD energy level. The Road Test Specification provides the duration time for the developed bench test. The n-Soft tool [1] is utilized for data reduction analysis. The Bench Test Specification of the Fuel subsystem is a pilot for this development.
Technical Paper

Can All Engine Wear Be Trapped in a Can?

THE study of engine life, carried out by investigating engine wear in typical service, and by then striving to find the most effective ways of controlling it, forms the basis of this paper on contaminants in lubricants. The investigation involved a study of engine wear in 20,000 miles of operation typical of the average driver. The average driver was selected by using test cars from an employee transportation car pool. At the conclusion of the tests it was found that the use of the full-flow oil filter proved to be the best method for restricting engine wear caused by contaminants that get inside the engine. It was also shown that after successfully eliminating large, solid particles, further restriction of engine wear would depend upon the ability of the oil to lubricate, and upon the engine design to provide the oil supply in a manner suitable for lubrication of each part of the engine.
Technical Paper

Chassis Dynamometer Simulation of Road Noise

This paper describes experimental methods for simulating and analyzing road noise using an artificial road surface mounted to a chassis dynamometer. The nature of the relationship of road noise to road surface is discussed, including the nature of sound produced by the artificial surface mounted to the dynamometer. A method is described for converting the harmonics usually produced in a chassis rolls test into a continuous spectrum. This method also smoothes statistical fluctuations which arise due to the short length of road simulated. Dynamometer techniques are shown to be particularly effective in separating sound contributions from the front and rear suspension, and in separating contributions due to road surface and the tire tread.
Technical Paper

Compensation for Road Noise in Automotive Entertainment Systems

Vehicle operation noise, even in the quietest cars, produces high sound pressure levels (SPL) at very low frequencies. This noise masks desired signals in and above this frequency range. A blind subjective test, using ten listeners, was undertaken to determine a frequency response equalization curve that would compensate for this noise under specific but realistic conditions. Starting with a 4 dB full-band level increase, an average of 40 listener responses showed a gentle rise in bass reaching an additional 4 dB at 50 Hz.
Technical Paper

Correlation Test: Guaporé Mountain Test vs Proving Ground

Downhill tests are widely used as a method of evaluation, development and validation of braking efficiency, friction pair durability, braking balance, as well as fade characteristics and recovery of friction material properties. This test procedure is used for both: passenger vehicles and light & heavy commercial vehicles. The energy levels in the brake system are higher on commercial vehicles and the thermal characteristics much more critical. Added to the fact that such tests are conducted on public highways, it has an intrinsic security risk for both the vehicle tested and all others around. Until a few years ago, it was still feasible to conduct tests downhill on different routes keeping a high security level. Given an increasing traffic on highways, where the test is currently carried out, a need to create a similar downhill procedure (called Guaporé Mountain Test) within a Proving Ground under controlled conditions has been noticed.
Technical Paper

Cruising the Information Super Highway Via the Automobile

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.
Technical Paper


TWENTY-FIVE-YEAR statistics, detailed in this paper, show declining accident and fatality rates despite radical increase in vehicle registrations and annual vehicle miles. The author shows how the passenger-car industry has built safety into vehicles to the point where-as an example-only 14% of accidents on the Pennsylvania Turnpike over its 13-year history were attributed to vehicle failures. Paralleling these efforts and the increasing emphasis on safer highways, better traffic management and driver education, are extensive studies aimed at bypassing the human factor and increasing human safety in automotive vehicles. Among those described here are crash investigations, laboratory tests of safety devices, and establishment through various other means of design criteria for human impact tolerance.
Technical Paper

Estimating the Population of Passenger Cars in Service

The approximate population of passenger cars in service and the rate of attrition of that population must be known when long range production plans are made, marketing strategies are developed, the total fuel need of the vehicles on U.S. roads is estimated, etc. Estimation of population is complex due to the lack of accurate data and the interactions between the parameters affecting attrition. Various methods are available to estimate the present and future population levels of passenger cars in service. Within the scope of this paper the projected populations of various passenger cars are compared and various attrition projection methods are discussed.
Technical Paper

Experimental Assessment Of Door Window Glass Smooth Operation And Tracking

Since the door glass windows are used regularly, they have a great influence on the vehicle owner's perception of vehicle quality. Today's customers demand that moveable door window glass operates smoothly. Experimental methods have been developed to evaluate window glass smoothness and positional stability. This paper presents experimental results that quantify the chattering and positional stability of the window glass. For window glass smooth operation and tracking, the measurements were taken on glass chatter, glass velocity, motor current, motor voltage, and glass stall force. The change in glass position was measured on the vehicle during several stages of four poster durability testing to evaluate window glass positional stability during road induced vibrations. Using these experimental methods, the designers should be able to evaluate several window glass functional requirements and achieve cost/time savings.
Technical Paper

Ford GT Body Engineering - Delivering the Designer's Vision in 24 Months

The objective was to engineer a world-class supercar body that faithfully reproduces the 2002 Concept and pays homage to the 1960's road racer. The car had to be designed, developed and launched in 24 months, while meeting tough requirements for function, weight, occupant package and aerodynamics. Challenging features such as the cantilevered door, “clamshell” engine decklid and a deeply contoured hood were to be included. This paper will discuss how a dedicated team of enthusiasts can have a flexible approach to the engineering process, material selections and manufacturing processes to achieve the designer's vision in 24 months (Figure 1).
Technical Paper

Headlight Beam Pattern Evaluation Customer to Engineer to Customer - A Continuation

The method of communication between the customer and the engineer has been refined to further improve the headlight beam pattern development process. The refinements included: a) reduction of word pairs used for semantic differential scaling and b) use of shortened questionnaire on night-roadway viewing zones. The added benefit of the new questionnaire method allows the engineer to evaluate the customer responses of the beam pattern within specific areas on the road scene. A statistical technique called factor analysis has been used to evaluate and to reduce the large number of semantic differential word pairs used in the previous work by Jack, O'Day and Bhise (1). A comparison of the two questionnaire forms used in the evaluation surveys was completed based on an evaluation of beam patterns in a dynamic drive situation.
Technical Paper

Motion Sensitivity as a Guide to Road Design

HUMAN perception thresholds to motions and the various characteristics of motions in six degrees of freedom are presented. Experiments made to establish these thresholds for disturbances of the duration or frequency that might arise from highway geometry—durations in the range of from one second to several hundred seconds—are described. Applications of motion sensitivity criteria in the design of vertical and horizontal highway curves and transitions are developed, with examples from company proving grounds in Arizona and Michigan. The resulting geometric features of the high-speed road systems differ in several important respects from conventional highway practice and previous automotive test-track designs.
Technical Paper

Off Track - Frame and Suspension Tuning (FAST)

Through Frame and Suspension Tuning (FAST) you can identify suspension and frame Set-ups in the lab with out risk to the car or driver. For on track verification the number of Set-ups can be reduced from an unlimited number to 2 or 3 and then optimized on the track, rather than developed on the track. This method can be used with all forms of racing. It has been applied to Indy, GT, Winston Cup, and Trans Am cars. Through the use of a road simulator we are able to evaluate and improve the frame and suspension dynamics in a laboratory. This paper will focus on the first step in the tuning process, frame tuning. If the frame is not tuned for the input energy conditions it can become an uncontrolled suspension component. The first step is to identify the frame dynamic characteristics. Operational deform shapes are measured to identify local and global motion. The frames are modified to optimize the response for the type of race track.
Technical Paper

Operational Spindle Load Estimation Methodology for Road NVH Applications

A new experimental methodology has been developed to quantify spindle loads of a vehicle under actual operational conditions. The methodology applies an indirect six degree-of-freedom (6 DOF) frequency response function (FRF) measurement technique to obtain three translation/force and three rotation/moment FRFs of the suspension system of the vehicle. The Inverse Frequency Response Function (IFRF) method estimates the spindle loads under operational conditions. The feasibility and applicability of the developed methodology for vehicle road NVH applications was experimentally demonstrated. The results show that the methodology provides accurate spindle load estimation over a broad frequency range. This methodology can be used for benchmarking and target setting of spindle loads to achieve desired road NVH performance as well as for diagnosing root causes in problem solving applications.
Technical Paper

Power Steering System Key-Life Test Procedure Development

As part of an effort to develop a laboratory steering system durability test, power steering system test procedure development was conducted. Fatigue damage to steering systems caused by road roughness was quantified utilizing data recorded from instrumented test vehicles and customer survey results. In addition, data recorded from customer vehicles were employed to determine fatigue damage to steering systems caused by driving style and road style inputs. Proving ground steering system test procedures that generate the same amount of damage to a steering system as that accumulated by the design target percentile customer for the design target miles of public road usage were developed.