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Engineers doing squeak and rattle testing of instrument panels (IP's) have successfully used large electrodynamic vibration systems to identify sources of squeaks and rattles (S&R's). Their successes led to demands to test more IP's, i.e., to increase throughput of IP's to reflect the many design, material, and/or manufacturing process changes that occur, and to do so at any stage of the development, production, or QA process. What is needed is a radically different and portable way to find S&R's in a fraction of the time and at lower capital cost without compromising S&R detection results.

Automotive outside rear view mirror shape has become an important consideration in achieving wind noise and aerodynamic performance objectives. This paper describes a two step process used to develop a mirror shape which meets both wind noise and aerodynamic objectives. First, basic understanding of door mounted verses sail mounted mirrors and shape parameters was obtained by evaluating selected shapes and studying their physical measurements relative to their measured responses. Relationships between the wind noise and drag responses revealed performance range limitations for sail mounted mirrors. Second, a central composite experimental design was utilized to more closely investigate door mounted mirror shape parameters to determine optimal mirror performance potential. The resulting empirical models developed were used to determine the best overall solution.

The current ability of the Virtual Aerodynamic/ Aeroacoustic Wind Tunnel to predict interior vehicle sound pressure levels is demonstrated using an automobile model which has variable windshield angles. This prediction method uses time-averaged flow solutions from a lattice gas CFD code coupled with wave number-frequency spectra for the various flow regimes to calculate the side window vibration from which the sound pressure level spectrum at the driver's ear is determined. These predictions are compared to experimental wind tunnel data. The results demonstrate the ability of this methodology to correctly predict wind noise spectral trends as well as the overall loudness at the driver's ear. A more sophisticated simulation method employing the same lattice gas code is investigated for prediction of the time-accurate flow field necessary to compute the actual side glass pressure spectra.

Wind noise is the sound made as air rushes over a moving vehicle. As other vehicle sound sources are improved, the wind noise becomes the dominant source under certain conditions. The purpose of this paper is to examine the relationship between the properties of wind noise and the human perception of this sound.We find that a particular loudness measure (Zwicker loudness as defined in IS0532B) is the prime factor governing the customer perception of wind noise.

The origin of the car radio is, like that of the automobile, an obscure one. This paper attempts to describe its early-history in the United States and Western Europe, briefly describing at the end some recent developments made possible by modern technology.

Acid rain in the U.S. is becoming a major environmental issue. This paper reviews the known information regarding pollution sources, impact on the environment and the role of the automobile in acid rain. Although natural sources of sulfur and nitrogen pollutants are equal to or greater than man-made sources on a global scale, many scientists believe man's activities are the major cause of high levels of acidity. Attempts to relate specific sources of SO2 to specific acid rain events in the northeastern U. S. have been unsuccessful. The roles of tall stacks, long range transport and dry vs. wet deposition are incompletely understood. Temporal and geographic trends in acidity are not well defined except for increased acidity in the southeast. About 30% of the acidity in rain in the northeast is due to HNO3. In the process of utilizing nitrates as a nutrient, plants partly neutralize the affect of HNO3 in the rain.

A laboratory wear test is used to evaluate the wear protection properties of new and used engine oils formulated for FFV service. Laboratory-blended mixtures of these oils with methanol and water have also been tested. The test consists of a steel ball rotating against three polished cast iron discs. Oil samples are obtained at periodic intervals from a fleet of 3.0L Taurus vehicles operating under controlled go-stop conditions. To account for the effects of fuel dilution, some oils are tested before and after a stripping procedure to eliminate gasoline, methanol and other volatile components. In addition to TAN and TBN measurements, a capillary electrophoresis technique is used to evaluate the formate content in the oils. The results suggest that wear properties of used FFV lubricants change significantly with their degree of usage.

The fuel injection process in the port of a firing 4-valve SI engine at part load and 25°C head temperature was observed by a high speed video camera. Fuel was injected when the valve was closed. The reverse blow-down flow when the intake valve opens has been identified as an important factor in the mixture preparation process because it not only alters the thermal environment of the intake port, but also strip-atomizes the liquid film at the vicinity of the intake valve and carries the droplets away from the engine. In a series of “fuel-on” experiments, the fuel injected in the current cycle was observed to influence the fuel delivery to the engine in the subsequent cycles.

A test cell was developed for evaluating a 6-speed automatic transmission. The target vehicle had an internal combustion 5.4L gasoline V8 engine. An electric dynamometer was used to closely simulate the engine characteristics. This included generating mean torque from the ECU engine map, with a transient capability of 10,000 rpm/second. Engine inertia was simulated with a transient capability of 20,000 rpm/second, and torque pulsation was simulated individually for each piston, with a transient capability of 50,000 rpm/second. Quantitative results are presented for the correlation between the engine driven and the dynamometer driven transmission performance over more than 60 test cycles. Concerns about using the virtual engine in validation testing are discussed, and related to the high frequency transient performance required from the electric dynamometer. Qualitative differences between the fueled engine and electric driven testing are presented.

A piezoelectrically driven vibrating cantilever blade is damped by a number of mechanisms including viscous damping in a still fluid and aerodynamic damping in a flow. By measuring the damping of devices operating at resonance in the 1 to 5 kHz region, one can measure such properties as mass flow, absolute pressure or the product of molecualar mass and viscosity. In the case of the mass flow measurement, the device offers a mechanical alternative to hotwire and hot film devices for the automotive application.

EQUIPMENT for measuring vibration in airplane structures and powerplants during actual flight is described in this paper. This development is the result of a cooperative research program carried out by the Bureau of Aeronautics of the U. S. Navy and the Massachusetts Institute of Technology with contributions of improvements in design and new features by the Sperry Gyroscope Co., Inc. In its essentials, the M.I.T.-Sperry Apparatus consists of a number of electrical pickup units which operate a central amplifying and recording unit. The recorder is a double-element photographic oscillograph. Each pickup is adapted especially to the type of vibration that it is intended to measure and is made so small that it does not appreciably affect the vibration characteristics of the member to which it is attached rigidly. By using a number of systematically placed pickups, all the necessary vibration information on an airplane can be recorded during a few short flights.

This paper outlines the key elements in a laboratory reliability verification test program for an automotive sub-system. Many of these elements are described in some detail through the various stages of development from prototype concept to production. By means of an actual case study, verification testing of the 1970 Ford Anti-Theft Steering Column, steps required to design tests which yield meaningful information and the rationale used to analyze the results are presented. The steering column on a late model automobile is a complex system which combines several functions and features; steering, shifting, warning devices (turn signal and emergency flashers), ignition switch, anti-theft devices plus several safety features. The effectiveness of the overall verification program is evaluated through the presentation of actual field-feedback results.

Several emission performance tests like Butane Working Capacity (BWC), Cycle Life, and ORVR load tests are required for the certification of a vehicle; these tests are both expensive and time consuming. This paper presents a test process based upon analytical simulation of BWC of an automotive carbon canister in order to greatly reduce the cost incurred in physical tests. The computational model for the fixed-bed system of a carbon canister is based upon non-equilibrium, non-Isothermal, and non-adiabatic algorithm to simulate the real life loading/purging of hydrocarbon vapors from this device.

A series of tests have been performed on a production vehicle to determine the characteristics of the external turbulent flow field in wind tunnel and road conditions. Empirical formulas are developed to use the measured data as source levels for a Statistical Energy Analysis (SEA) model of the vehicle structural and acoustical responses. Exterior turbulent flow and acoustical subsystems are used to receive power from the source excitations. This allows for both the magnitudes and wavelengths of the exterior excitations to be taken into account - a necessary condition for consistently accurate results. Comparisons of measured and calculated interior sound levels show good correlation.

Panel acoustic contribution analysis (PACA) is an advanced engineering tool to improve the NVH quality of vehicles. Using PACA areas of vehicle body panels are categorized according to their contribution to the total sound. Positive contribution areas increase the sound level as vibration amplitude increases, negative contribution areas decrease the sound level as vibration amplitude increases, and neutral areas have no significant effect on the sound level. This knowledge is important to guide vehicle NVH refinement. This paper presents the technical approach of PACA and the results of an experiment used to validate the PACA techniques. Vehicle application results to improve NVH quality and reduce weight are also included.

This paper explores the extent to which standard dilution tunnel measurements of motor vehicle exhaust particulate matter modify particle number and size. Steady state size distributions made directly at the tailpipe, using an ejector pump, are compared to dilution tunnel measurements for three configurations of transfer hose used to transport exhaust from the vehicle tailpipe to the dilution tunnel. For gasoline vehicles run at a steady 50 - 70 mph, ejector pump and dilution tunnel measurements give consistent results of particle size and number when using an uninsulated stainless steel transfer hose. Both methods show particles in the 10 - 100 nm range at tailpipe concentrations of the order of 104 particles/cm3.

The Vehicle Electrical System Computer Aided Design (VESCAD) tool is a means by which the vehicle electrical system, including all wiring and the components attached to wiring can be laid out over an outline of the planform (looking down on the vehicle) view of the vehicle. This graphical representation of the vehicle electrical system is linked to a database that contains the definition of all the wiring of the vehicle plus electrical component attributes. The vehicle electrical system can be composed and completely manipulated graphically, using a mouse, and the database is dynamically changed, including automatic re-routing of the wiring in the wiring harnesses. A complete series of reports can be generated once a vehicle electrical system is configured using VESCAD. All of the reports can be keyed by component(s), harness(es), subsystem(s) or the entire vehicle.

Brake related warranty costs are a major concern to the automotive industry. Large part of these costs are due to noise, more particularly due to the brake squeal complaints. Computer-aided engineering solutions have attracted a lot of attention from the engineering and development community for more effective brake product development. Recently, three brake squeal analysis methods were implemented on disc type brakes in a vehicle program at Ford. This paper summarizes the results and documents the experience obtained during implementation in the vehicle CAE process.

As vehicle tailpipe emission levels decrease with improvements in emission control technology and reformulation of gasolines, exhaust hydrocarbon levels begin to approach the levels in ambient air. Hydrocarbon speciation at these low levels requires high sensitivity capillary gas chromatography methods. In this study, a mixture of “synthetic” exhaust was prepared at two concentration levels (approximately 5 ppm C and 10 ppm C), and was analyzed by the widely-used Auto/Oil Air Quality Improvement Research Program (AQIRP) Phase II (gas chromatography) speciation method with a sensitivity of 0.005 ppm C for individual species. The mixture at each concentration level, along with a sample of ambient air, was analyzed a total of 20 times on 10 separate days over a 2½ week period. Concentrations of total hydrocarbons (HCs) and individual species (using the AQIRP library) were measured; averages and standard deviations were calculated.

Liquid fuels and the fuel vapors in equilibrium with them typically differ in composition. These differences impact automotive fuel systems in several ways. Large compositional differences between liquid and vapor phases affect the composition of species taken up within the evaporative emission control canister, since the canister typically operates far from saturation and doesn't reach equilibrium with the fuel tank. Here we discuss how these differences may be used to diagnose the mode of emission from a sealed container, e.g., a fuel tank. Liquid or vapor leaks lead to particular compositions (reported here) that depend on the fuel components but are independent of the container material. Permeation leads to emissions whose composition depends on the container material. If information on the relative permeation rates of the different fuel components is available, the results given here provide a tool to decide whether leakage or permeation is the dominant mode of emission.