Search Results

The flow field contained within ten planes inside a cylinder of a 3.5 liter, 24-valve, V-6 engine was mapped using a three-dimensional Laser Doppler Velocimetry (3-D LDV) system. A total of 1,548 LDV measurement locations were used to construct the time history of the in-cylinder flow fields during the intake and compression strokes. The measurements began during the intake stroke at a crank angle of 60° ATDC and continued until approximately 280° ATDC. The ensemble averaged LDV measurements allowed for a quantitative analysis of the dynamic in-cylinder flow process in terms of tumble and swirl motions. Both of these quantities were calculated at every 1.8 crank degrees during the described measurement interval. Tumble calculations were performed about axes in multiple planes in both the Cartesian directions perpendicular to the plane of the piston top. Swirl calculations were also accomplished in multiple planes that lie parallel to the plane of the piston top.

The SAE Recommended Practice J963 “Anthropomorphic Test Device for Dynamic Testing” describes a standard 50th percentile adult male anthropomorphic test dummy. For nearly three years the Crash Test Dummy Task Force worked with the limited data available in selecting values for the body dimensions and ranges of motion. The data for specifying the values of mass distribution were developed experimentally as was a test procedure for determining the dynamic spring rate of the thorax.

TFC/IW, total fuel consumption divided by inertia (test) weight is a useful concept in analyzing the total or composite fuel economy generated in thousands of tests using the carbon balance technique in EPA Federal Test Procedure and Highway Driving Cycle. TFC/IW is a measure of drive train efficiency that requires no additional complicating assumptions. It is applicable to one test or a fleet representing many tests.

A running loss test procedure has been developed which integrates a point-source collection method to measure fuel evaporative running loss from vehicles during their operation on the chassis dynamometer. The point-source method is part of a complete running loss test procedure which employs the combination of site-specific collection devices on the vehicle, and a sampling pump with sampling lines. Fugitive fuel vapor is drawn into these collectors which have been matched to characteristics of the vehicle and the test cell. The composite vapor sample is routed to a collection bag through an adaptation of the ordinary constant volume dilution system typically used for vehicle exhaust gas sampling. Analysis of the contents of such bags provides an accurate measure of the mass and species of running loss collected during each of three LA-4* driving cycles. Other running loss sampling methods were considered by the Auto-Oil Air Quality Improvement Research Program (AQIRP or Program).

For designing new products or developing new specifications, the reliability performance of systems and components experienced by the customer provides invaluable information for the engineer. This information, not only provides for the visibility of reliability requirements, but also an awareness of potential degradation of the systems and components during its life cycle. In this paper, a method is presented for predicting vehicle system and component reliability from vehicle fleet repair data. This method combines sampling stratification, computer data analysis and statistical modeling techniques into a reliability analysis procedure to provide reliability prediction. Specifically, published vehicle fleet data was used to provide the basis for predicting the vehicle system and component reliability at any mileage level.

Vacuum insulation and phase-change thermal storage have been used to enhance the heat retention of a prototype catalytic converter. Storing heat in the converter between trips allows exhaust gases to be converted more quickly, significantly reducing cold-start emissions. Using a small metal hydride, the thermal conductance of the vacuum insulation can be varied continuously between 0.49 and 27 W/m2K (R-12 to R-0.2 insulation) to prevent overheating of the catalyst. A prototype was installed in a Dodge Neon with a 2.0-liter engine. Following a standard preconditioning and a 23-hour cold soak, an FTP (Federal Test Procedure) emissions test was performed. Although exhaust temperatures during the preconditioning were not hot enough to melt the phase-change material, the vacuum insulation performed well, resulting in a converter temperature of 146°C after the 23-hour cold soak at 27°C.

An extensive program has been established to screen and evaluate heat- and corrosion-resistant alloys that may have some potential application in emission-control systems anywhere from the exhaust manifold to the tailpipe. The various phases of this program, which include tests conducted in air and controlled exhaust atmospheres at temperatures between 1300-2200°F are described. Some selected test data and the results of metallographic studies are presented to illustrate how representative alloys react to the various test conditions. The characteristics and functions of the basic emission-control devices are reviewed in light of their effect upon materials requirements.

This paper presents the development of a test procedure for evaluation of inadvertent deployment of air bags. The methodology and early development of the procedure is discussed along with additional criteria thought to be required for trucks and sport utility vehicles. Tests conducted address severe off-road use in relation to air bag sensing systems. Data is collected from accelerometers. After worst case test conditions are identified (examples include rough road, snow plowing and jerk towing events), the data is analyzed and comparisons for design decisions can be made.

The UBHC emissions during cold starting need to be controlled in order to meet the future stringent standards. This requires a better understanding of the characteristics of the time resolved UBHC signal measured by a high frequency FID and its phasing with respect to the valve events. The computer program supplied with the instrument and currently used to compute the phase shift has many uncertainties due to the unsteady nature of engine operation during starting. A new technique is developed to measure the in-situ phase shift of the UBHC signal under the transient thermodynamic and dynamic conditions of the engine. The UBHC concentration is measured at two locations in the exhaust manifold of one cylinder in a multicylinder port injected gasoline engine. The two locations are 77 mm apart. The downstream probe is positioned opposite to a solenoid-operated injector which delivers a gaseous jet of hydrocarbon-free nitrogen upon command.

Typical sand-casting techniques have been shown to be inappropriate in pouring particulate reinforced aluminum metal matrix composite (Al-MMC) castings. New gating/risering configurations were necessary to produce castings of acceptable soundness. Several automotive components, including brake rotors, cylinder liners and camshaft thrust plates, were prepared using special techniques. Initial durability test results of several Al-MMC prototype components are presented.

The head Severity Index concept has attracted widespread attention in the automotive industry. This index is intended to estimate human survivability in a systematic way without relying on judgment values. It is employed for evaluating the probability of internal head injury for those indeterminate conditions where the human tolerance limits are not clearly defined. This paper discusses a damage index which is believed to be superior to the current Severity Index in several respects: 1. The concept is applicable to internal injuries of the torso as well as the head. 2. It is felt to describe the actual damage mechanism more directly. 3. It fits the Wayne State head tolerance curve better than the Severity Index. 4. It is suitable for analyzing impact pulses of any time duration. Examples cited in this paper include rocket sled exposures (250 ms duration) down to severe head impacts (5 ms duration). 5. It is more convenient to employ.

Federal legislation mandates that automotive OEMS provide occupant protection in collisions involving front and side impacts This legislation, which is to be phased-in over several years, covers not only passenger cars but also light-duty trucks and multipurpose passenger vehicles (MPVs) having a gross vehicle weigh rating (GVWR) of 8,500 lb (3,850 kg) or less. During a frontal impact, occupants within the vehicle undergo rapid changes in velocity. This is primarily due to rapid vehicle deceleration caused by the rigid nature of the vehicle's metal frame components and body assembly. Many of today's vehicles incorporate deformable, energy-absorbing (EA) structures within the vehicle structure to manage the collision energy and slow the deceleration which in turn can lower the occupant velocity relative to the vehicle. Occupant velocities can be higher in light-duty trucks and MPVs having a full-frame structure resulting in increased demands on the supplemental restraint system (SRS).

Testing of an OHC valve train with hydraulic lash adjuster in which the valve displacements, velocities and accelerations were measured and analyzed in both time and frequency domains, coupled with analysis of the frequency content of the valve acceleration function and its ramps, show that traditional designs of the opening and closing ramps used on some IC engine valve cams can exacerbate vibration in the follower system causing higher levels of spring surge and noise. Suggestions are made for improvement to the design of the beginning and ending transitions of valve motion which can potentially reduce dynamic oscillation and vibration in the follower train.

This paper discusses the development and implementation of a 16 channel data acquisition system for high “G” impact testing which includes a self-contained, on-board data acquisition unit, a programmer-exerciser and debriefing subsystems. The microprocessor controlled, on-board unit contains all signal conditioning, A/D conversion hardware and logic to store 4K 12 bit samples of data per channel. This unit will debrief into an oscilloscope, a desk-top computer or a large disk-based minicomputer system. Advantages over previous systems include the elimination of costly hardware (such as umbilical cables and recorders), and a reduction in pre-test preparation and data processing time.

This paper describes the development of a rubber-like skin Finite Elements Model (FEM) for the Hybrid III headform and an experimental method to determine its material properties. The finite element modeling procedures, using material parameters derived from tests conducted on the headform skin (rubber) material, are described. Dynamic responses and computations of HIC using the developed headform model show that an Elastic-Plastic Hydrodynamic (EPH) material model of the rubber can be used for headform impact simulations. The results obtained from the headform simulation using an EPH rubber material model and drop tower tests of the headform on both a rigid and a deformable structure will be compared, in order to show the applicability of the EPH model.

THE design and development of the new valve-in-head V-8 Chrysler engine of 7.5 compression ratio are described here. Among the features discussed by the authors are: the hemispherical combustion chamber, V-8 cylinder arrangement, double-breaker distributor, “thermal flywheel” on automatic choke, and exhaust-heated and water-jacketed throttle bodies. The hemispherical combustion chamber was adopted after it had displayed excellent volumetric and indicated thermal efficiencies, and an ability to maintain these high efficiencies in service. The high volumetric efficiency, for example, is considered to be due to such design features as valves not crowded together, nor surrounded closely by the combustion-chamber walls. They are thereby fully effective in the flow of the fuel-air mixture and the exhaust gases. The authors also present performance data for this engine, which, at full throttle, develops 180 hp at 4000 rpm and 312 ft-lb of torque at 2000 rpm.

Testing for vehicle emissions and fuel economy certification occurs primarily on chassis dynamometers in a laboratory setting and therefore the actual road conditions, such as forces due to tire rolling resistance and internal friction, must be simulated. Test track coastdown procedures measure vehicle road load forces and produce an equation which relates these forces to velocity. The recent inclusion of onboard anemometry has allowed the coastdown procedure to account for varying wind effects; however, the new anemometer based mechanical loss coefficients do not take into account ambient weather conditions. The two purposes of this study are (1) to determine the new tire rolling resistance temperature correction coefficient that should be used when test ambient temperature is different from the standard reference value of 68°F, and (2) to investigate the effects of auxiliary measurements, such as other ambient conditions and vehicle settings, on this correction coefficient.

A cycle-by-cycle analysis of HC emissions from each cylinder of a four-stroke V-6, 3.3 L production engine was made during cold start. The HC emissions were measured in the exhaust port using a high frequency flame ionization detector (FID). The effect of the initial startup position of the piston and valves in the cycle on combustion and HC emissions from each cylinder was examined. The mass of fuel injected, burned and emitted was calculated for each cycle. The equivalence ratio of the charge in the firing cycles was determined. The analysis covered the first 120 cycles and included the effect of engine transients on HC emissions.

WORK done in a development program relative to camshafts and tappets in the design of the Chrysler overhead-valve V-8 engine is described. The types of failure encountered are categorized as wear, scuffing, and fatigue. An accelerated test procedure was designed to promote early cam-tappet failures, and the development work was predicated upon the results obtained therefrom. Among the variables affecting the failure conditions, major emphasis was placed on material development. Specifically, the greater amount of time was spent in determining the optimum tappet material, while some time was devoted to the camshaft material. A combination of adjusted chemical composition and heat-treatment of hardenable cast iron for camshaft and tappets provided the best solution to the failure problems.

In anticipation of complying with European standards for impact protection, an instrument panel design was analyzed to determine A. impact zone boundaries B. impact test velocitiesfor the head of a front seat passenger. Chrysler computer aided design (C.A.D.) surfacing capabilities were utilized in the solution. Early knowledge of impact zone location is important to intelligent design decisions; knowledge of impact velocities aids in performing compliance testing.