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Using the CDC (SAE J224), a comparison of the NASS data and the UMTRI field accident files (UM series) indicates a similar distribution of offset frontal crashes. Offset frontal damage occurs in 56-61% of crashes, often involving more than one third of the front of the car. Lap-shoulder belted drivers sustain more AIS 2 or greater injuries when there is interior intrusion and occur more often when the offset damage is in front of the driver. However, this may well be due to the severity of the crash. European studies have no uniformity as to offset frontal collision descriptors are difficult to interpret, or to compare one to another.

A global, systems-level model which characterizes the thermal behavior of internal combustion engines is described in this paper. Based on resistor-capacitor thermal networks, either steady-state or transient thermal simulations can be performed. A two-zone, quasi-dimensional spark-ignition engine simulation is used to determine in-cylinder gas temperature and convection coefficients. Engine heat fluxes and component temperatures can subsequently be predicted from specification of general engine dimensions, materials, and operating conditions. Emphasis has been placed on minimizing the number of model inputs and keeping them as simple as possible to make the model practical and useful as an early design tool. The success of the global model depends on properly scaling the general engine inputs to accurately model engine heat flow paths across families of engine designs. The development and validation of suitable, scalable submodels is described in detail in this paper.

The U.S. EPA initiated the Common Sense Initiative (CSI) to develop “Cleaner, Cheaper, Smarter” environmental policy and management practices. This paper addresses the application of life cycle design and assessment tools to automotive instrument panels (IP) as part of the Automotive Manufacturing Sector CSI pilot project investigation. For this study, an “average IP” was modeled based on the instrument panels of three mid-sized U.S. car models: 1995 Chevrolet Lumina, 1996 Dodge Intrepid and 1996 Ford Taurus. This “average IP” consisted of seventeen different materials and weighed over 22 kg (49 lbs.). A life cycle inventory analysis was conducted to evaluate the environmental burdens associated with materials production, manufacturing, use, and retirement. A thorough evaluation of solid waste production and energy consumption was completed and partial inventories of air emission and water effluent releases were also conducted.

An experimental heat release rate analysis was conducted on a six cylinder, 12.7 liter Detroit Diesel Series 60 turbocharged engine operating under steady state conditions. The overall chemical, or gross, rate of heat release and the net apparent rate of heat release were determined from experimental measurements. The gross, time averaged, heat release rate was determined by two separate concepts/methods using exhaust gas concentration measurements from the Nicolet Rega 7000 Real Time Exhaust Gas Analyzer and the measured exhaust gas flow rate. The net apparent rate of heat release was determined from the in-cylinder pressure measurements for each of the six cylinders, averaged over 80 cycles. These pressure measurements were obtained using a VXI based Tektronix data acquisition system and LabVIEW software. A computer algorithm then computed the net apparent rate of heat release from the averaged in-cylinder pressure measurements.

A comprehensive quasi-dimensional computer simulation of the spark-ignition (SI) engine was used to explore part-load, fuel economy benefits of the Variable Stroke Engine (VSE) compared to the conventional throttled engine. First it was shown that varying stroke can replace conventional throttling to control engine load, without changing the engine characteristics. Subsequently, the effects of varying stroke on turbulence, burn rate, heat transfer, and pumping and friction losses were revealed. Finally these relationships were used to explain the behavior of the VSE as stroke is reduced. Under part load operation, it was shown that the VSE concept can improve brake specific fuel consumption by 18% to 21% for speeds ranging from 1500 to 3000 rpm. Further, at part load, NOx was reduced by up to 33%. Overall, this study provides insight into changes in processes within and outside the combustion chamber that cause the benefits and limitations of the VSE concept.

Piston heat transfer measurements were taken under varying knock intensity in a modern spark-ignition engine combustion chamber. For a range of knocking spark timings, two knock intensity levels were obtained by using a high (80°C) and a low (50°C) cylinder head coolant temperature. Data were taken with a central and a side spark plug configuration. When the spark-plug was placed at the center of the combustion chamber, a linear variation of peak heat flux with knock intensity was found in the end-gas region. Very large changes in peak heat flux (on the order of 100%) occurred at probes whose relative location with respect to the end gas zone changed from being within (80°C coolant case) to being outside the zone (50°C coolant case). With side spark-plug, distinct differences in peak heat flux occurred at all probes and under all knock intensities, but the correlation between knock intensity and heat flux was not linear.

Since muscles act to translate an electrical impulse from the central nervous system into motion, it is essential to have a suitable mathematical model for muscles and groups of muscles for a virtual soldier environment. This paper presents a methodology in which the muscle contraction is broken down into three distinct physiological processes: calcium release and re-absorption by the sarcoplasmic reticulum, the rate at which calcium binds and unbinds to troponin, and the generation of force due to cross-bridge cycling and the elasticity of the muscle fibers. These processes have been successfully modeled by Ding and Wexler as a system of coupled differential and algebraic equations. These equations give the calcium-time history and the force time history of the muscle. By varying the electrical stimulation rates, the muscles can produce forces of varying magnitude and duration over which the force can be maintained.

Simulations of humans performing seated reaches require accurate descriptions of the movements of the body segments that make up the torso. Data to generate such simulations were obtained in a laboratory study using industrial, auto, and truck seats. Twelve men and women reached to push-button targets located throughout their right-hand reach envelopes as their movements were recorded using an electromagnetic tracking system. The data illustrate complex patterns of motion that depend on target location and shoulder range of motion. Pelvis motion contributes substantially to seated reach capability. On padded seats, the effective center of rotation of the pelvis is often within the seat cushion below the pelvis rather than at the hips. Lumbar spine motions differ markedly depending on the location of the target. A categorization of reach targets into four zones differentiated by torso kinematics is proposed.

An experimental study has been carried out to provide qualitative and quantitative insight into gas to wall heat transfer in a gasoline fueled Homogeneous Charge Compression Ignition (HCCI) engine. Fast response thermocouples are embedded in the piston top and cylinder head surface to measure instantaneous wall temperature and heat flux. Heat flux measurements obtained at multiple locations show small spatial variations, thus confirming relative uniformity of in-cylinder conditions in a HCCI engine operating with premixed charge. Consequently, the spatially-averaged heat flux represents well the global heat transfer from the gas to the combustion chamber walls in the premixed HCCI engine, as confirmed through the gross heat release analysis. Heat flux measurements were used for assessing several existing heat transfer correlations. One of the most popular models, the Woschni expression, was shown to be inadequate for the HCCI engine.

Despite remarkable progress made over the past 30 years, automobiles continue to be a major source of hydrocarbon emissions. The objective of this study is to evaluate whether variable exhaust valve opening (EVO) and exhaust valve closing (EVC) can be used to reduce hydrocarbon emissions. An automotive gasoline engine was tested with different EVO and EVC timings under steady-state and start-up conditions. The first strategy that was evaluated uses early EVO with standard EVC. Although exhaust gas temperature is increased and catalyst light-off time is reduced, the rapid drop in cylinder temperature increases cylinder-out hydrocarbons to such a degree that a net increase in hydrocarbon emissions results. The second strategy that was evaluated uses early EVO with early EVC. Early EVO reduces catalyst light-off time by increasing exhaust gas temperature and early EVC keeps the hydrocarbon-rich exhaust gas from the piston crevice from leaving the cylinder.

THIS paper reports work begun in 1935 at the instigation of the Murray Corp. of America. Methods used in studying the relations between the automobile seat cushion and its function in transporting passengers with greater comfort and less fatigue are described. Constructed for this purpose was a piece of apparatus called the Universal Test Seat, whose dimensions were completely adjustable with arrangements to vary the distribution of the supporting pressure in any manner which seemed most comfortable to the passenger. The authors describe tests made by use of this apparatus, present summaries of some of the results recorded and conclude that, to give the passenger the maximum comfort and least fatigue, the following mechanical objectives should be attained by the cushion: 1. To support the passenger over a large area to get the smallest unit pressure on the flesh; 2.

Based on a review of existing theoretical and empirical knowledge of the mechanics of pneumatic tires and tire/vehicle systems, a requirement is defined for experimental data relating the shear forces developed at the tire-road interface to the kinematic variables of influence. Test equipment to satisfy this requirement consists of two complementary pieces of apparatus: a laboratory facility which is a modified version of the B. F. Goodrich flat-bed tester, and a mobile device which consists of a three-component (Fx, Fy, Mz) strain-gage dynamometer mounted on a heavy duty highway tractor. The latter provides a capability for testing at speeds up to 70 mph, normal loads up to 2000 lb, tire sideslip angles up to 18 deg, and steady state or programmed variations in longitudinal tire slip from fully locked (100% slip) to 30% overdriven (-30% slip). Representative samples of tire mechanics data obtained using the new equipment are presented and discussed.

Originally written in 1976 and previously revised in 1983, The Maintenance Council (TMC) Recommended Practice RP-404B is intended to enhance the safety of motor carrier employees by providing guidance regarding the purchase and use of access systems on heavy truck and truck tractors. Compliance with the recommended practice is intended to permit anyone entering or exiting a cab to have three limbs in contact with the truck or truck-tractor at arty time. The scope of the recommended practice covers access systems to the cab and rear of cab areas of all types of heavy trucks and truck tractors, in contrast to Bureau of Motor Carrier Safety (BMCS) regulations which applies only to Cab Over Engine (COE) tractors. The Maintenance Council recommended practice also varies from the BMCS requirements in that it remains a design oriented document.

Investigating combustion characteristics of oxygenated gasoline and gasoline blended ethanol is a subject of recent interest. The non-linearity in the interaction of fuel components in the oxygenated gasoline can be studied by developing chemical kinetics of relevant surrogate of fewer components. This work proposes a new reduced four-component (isooctane, heptane, toluene, and ethanol) oxygenated gasoline surrogate mechanism consisting of 67 species and 325 reactions, applicable for dynamic CFD applications in engine combustion and sprays. The model introduces the addition of eight C1-C3 species into the previous model (Li et al; 2019) followed by extensive tuning of reaction rate constants of C7 - C8 chemistry. The current mechanism delivers excellent prediction capabilities in comprehensive combustion applications with an improved performance in lean conditions.

A failure prediction methodology that can predict sheet metal failure under arbitrary deformation histories including rotating principal stretch directions and bending/unbending with consideration of damage evolution is reviewed in this paper. An anisotropic Gurson yield criterion is adopted to characterize the effects of microvoids on the load carrying capacity of sheet metals where Hill’s quadratic anisotropic yield criterion is used to describe the matrix normal anisotropy and planar isotropy. The evolution of the void damage is based on the growth, nucleation and coalescence of microvoids. Mroz’s anisotropic hardening rule, which was proposed based on the cyclic plastic behavior of metals observed in experiments, is generalized to characterize the anisotropic hardening behavior due to loading/unloading with consideration of the evolution of void volume fraction. The effects of yield surface curvature are also included in the plasticity model.

The emission of excessive quantities of NOx when the automobile air conditioner is turned on has received a fair amount of attention in recent years. Since NOx is a smog precursor, it is important to understand the reasons for this jump in emissions especially on hot sunny days when air conditioner usage is at a maximum. A simple thermodynamic model is used to demonstrate how the torque from a typical air conditioner compressor is mainly related to the ambient temperature. The compressor's on-off cycling patterns are also characterized. Since the compressor significantly loads the engine, it affects fuel economy and emissions. The key independent variable that we employ to represent engine load is fuel rate. The correlations between engine-out NOx emissions and fuel rate are shown for a number of light duty vehicles and trucks. From these, a physical model for engine-out NOx emissions (with and without air conditioning) is presented.

The addition of synthetic traffic to a driving simulation greatly enhances the realism of the virtual world. Giving this traffic human-like behavior is likewise desirable, and has been the focus of some research over the past few years. This paper presents a modular architecture for including autonomous traffic in a driving simulation, and describes the first steps taken toward the application of this architecture to the DaimlerChrysler Auburn Hills Simulator. By separating the planning part of the agent from the low-level control and vehicle dynamics systems, the described architecture permits the inclusion of powerful, previously developed components in a straightforward way; in the present application, agents use Soar to reason about their actions. This paper gives an overview of the structures of the agents, and of the entire system, describes the components and their implementations, and discusses the current state of the project and plans for the future.

This paper presents an overview of techniques for measuring friction using bench tests and fired engines. The test methods discussed have been developed to provide efficient, yet realistic, assessments of new component designs, materials, and lubricants for in-cylinder and overall engine applications. A Cameron-Plint Friction and Wear Tester was modified to permit ring-in-piston-groove movement by the test specimen, and used to evaluate a number of cylinder bore coatings for friction and wear performance. In a second study, it was used to evaluate the energy conserving characteristics of several engine lubricant formulations. Results were consistent with engine and vehicle testing, and were correlated with measured fuel economy performance. The Instantaneous IMEP Method for measuring in-cylinder frictional forces was extended to higher engine speeds and to modern, low-friction engine designs.

A numerical model is presented that is capable of isolating and quantifying the heat flux from the gas within the bag to the air bag fabric due to internal surface convection during the inflator discharge period of an air bag deployment. The model is also capable of predicting the volume averaged fabric temperatures during the air bag deployment period. Implementation of the model into an air bag deployment code, namely Inflator Simulation Program (ISP), is presented along with the simulation results for typical inflators. The predicted effect of the heat loss from the bag gas to the fabric on the internal bag gas temperature and pressure and the resulting bulk fabric temperature as a function of fabric parameters and the inflator exit gas properties are presented for both permeable and impermeable air bag fabrics.

Previous work done at the University of Michigan shows the capability of the vacuum-insulated catalytic converter (VICC) to retain heat during soak and the resulting benefits in reducing cold start emissions. This paper provides an improved version of the design which overcomes some of the shortcomings of the previous model and further improves the applicability and benefits of VICC. Also, newer materials have been evaluated and their effects on heat retention and emissions have studied using the 1-D after treatment model. Cold start emissions constitute around 60% to 80% of all the hydrocarbon and CO emissions in present day vehicles. The time taken to achieve the catalyst light-off temperature in a three-way catalytic converter significantly affects the emissions and fuel efficiency. The current work aims at developing a method to retain heat in catalytic converter, thus avoiding the need for light-off and reducing cold start emissions effectively.