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A study was conducted by General Motors (GM) to further expand upon the currently available research regarding the safety belt buckle environment during full scale vehicle crash tests. A previous study by GM [1] focused on the environment experienced by safety belt buckles in planar, non-rollover, vehicle crash conditions. This study expands upon that work by measuring buckle acceleration and webbing tension in a variety of full scale vehicle rollover crash tests. A variety of test vehicles, rollover crash types, seating positions, roll directions, test speeds, and safety belt systems were included in the study. Emphasis was placed on examination of the buckle response data during vehicle-to-ground impacts (roof, body, and wheel). This study reports on data recorded from 20 full scale rollover crash tests with 40 instrumented end release safety belt buckles.

The focus of this paper is an air charge estimator for engine control system applications which do not feature a mass air flow (MAF) sensor. The proposed approach, beyond its independency of a MAF sensor, is designed to be compatible with the confines of a typical production control system configuration. The air charge estimation algorithm is based on mean-value models for the manifold pressure dynamics and the gas flows through the throttle and valve orifices. It involves nominal static models for the volumetric efficiency of the engine and for the throttle discharge coefficient. The static models for those parameters are complemented with correction factors that are adjusted on-line. The update of the volumetric efficiency correction is implemented in the form of a Kalman-filter which uses the difference between the measured and the modeled manifold pressure as an error metric.

Although rollover crashes represent a small fraction (approximately 3%) of all motor vehicle crashes, they account for roughly one quarter of crash fatalities to occupants of cars, light trucks, and vans (NHTSA Traffic Safety Facts, 2004(1)). Therefore, the National Highway Traffic Safety Administration (NHTSA) has identified rollover injuries as one of its safety priorities. Motor vehicle manufacturers are developing technologies to reduce the risk of injury associated with rollover collisions. During a series of rollover sensor development tests conducted by General Motors, data was collected and analyzed to identify the required load and energy absorption characteristics of the ejection mitigation device used. General Motors then derived from that data a component level test that can be used to evaluate the potential of a rollover capable side air bag to mitigate the likelihood of ejection in a majority of rollover tests.

This paper presents the results of a study of CFD simulation of NASCAR's Car of Tomorrow (COT). Aerodynamic flowfield and forces are computed to investigate effects of moving ground and rotating wheel conditions. Mesh dependence and convergence behavior of various forces is also analyzed to develop an accurate analysis process. Thereafter, the analysis process is applied to compute effects of various design changes of the baseline COT. CFD analysis showed that the lift on the COT decreases due to the moving ground and rotating wheel (MVG&RW) effects. However the drag increases, in contrast to the typical observations for passenger cars. This was attributed to smaller interaction of the underbody flow with the wake flow. The aerodynamic force increments for design changes showed that MVG&RW may not be required to estimate effects of some of the design changes.

Euro 6 European legislation emission limits, expected to be introduced around the 2014 timeframe, Lean NOx Trap (LNT) Aftertreatment technology is today considered one the of candidate technology to allow diesel Engine to meet the future Euro 6 limit. The working principle of the LNT is based on its capability to store the NOx engine out during the normal lean (excess of Oxygen) phase operation condition of the Diesel engine. The NOx will be then reduced in a dedicated regeneration phase which consist in creating for relatively short time a rich exhaust gas condition inside the LNT. The LNT regeneration strategy lead to run a Diesel engine with a rich mixture out of the combustion as a Gasoline engine. This can be obtained using advanced air and fuel management. The fuel management implicate the use of delayed injections (after and/or post injections) which can have a direct impact on oil dilution.

Carbon, hydrogen and oxygen are major elements in modern fuels. Varying combinations of these elements in motor fuel alter the stoichiometric air-fuel ratio (A/F). Stoichiometric A/F ratio is an important parameter in engine calibration affecting vehicle performance, emissions and fuel economy. With increasing use of ethanol in automotive fuels in recent years, since it can be made from renewable feedstocks, oxygen contents in fuel are increasing. Oxygen contents can be around 1.7 mass % in European E5 gasoline or 3.5 mass % in U.S. E10 gasoline and up to 29 mass % in E85 fuel. The increase in oxygen content of fuel has resulted in changes in other physical and chemical properties due to the differences between ethanol and hydrocarbons refined from fossil oil. A previous paper (SAE 2010-01-1517) discussed the change in energy content of automotive fuel and the estimation of net heating values from common fuel properties.

Continuing pressure to reduce mass and cost of vehicles is driving the development of new high strength steel products with improved combinations of strength and formability. Galvanized, cold rolled dual phase steel products are new alternatives to conventional high strength low alloy (HSLA) steel for strength limited applications in vehicles. These steels have higher tensile strengths than HSLA products with nearly equivalent formability. This paper compares the performance of HSLA and dual phase sheet steel products in a series of drop tower tests. Samples were prepared by stamping the steel sheets into typical rail-type parts using a production-intent die process. The parts were sectioned, and subsequently fabricated into hat-shaped assemblies that were then dynamically crushed by a drop weight. The experiments were designed such that the entire energy input by the drop weight was absorbed by the samples.

Electrical ac impedance measurements were used for tracking the time dependence of the electrical properties (resistivity and permittivity) for 18 fully formulated engine oils during two types of engine dynamometer tests: high-temperature high-load (HTHL) and postal cycle (PC). The signatures in the time dependence of the electrical resistivity of engine oil at beginning-of life (BOL) and during early service differentiate both oil service classifications and test/driving conditions. The air content in engine oils can be determined quantitatively from the permittivity with a detection limit of 0.2 vol%. The significance of our results and their consequences for on-board monitoring of engine oil through sensing technology based on electrical ac impedance measurements are discussed.

The advent of Enhanced Inspection/Maintenance (I/M) Programs brought a need for specialized diagnostics and repair procedures to enable the proper repair of failing vehicles. Unlike previous emission testing programs. Centralized Enhanced I/M Programs such as IM240 present a unique challenge for technicians - the inability to confirm the effectiveness of the repair without the use of similar equipment. This inability to confirm that proper repairs have been made to meet IM240 requirements coupled with a desire not to risk repeat vehicle failures inspired General Motors to investigate all known equipment and procedures relative to this subject GM has conducted a study to measure the effectiveness of various IM240 repair confirmation products and procedures in predicting IM240 outcomes. Appropriate statistical methods were employed to interpret the data acquired in this study. Also collected was vehicle repair and exhaust gas failure information on the vehicles tested.

Since its inception, the internal combustion (IC) engine has undergone continuous improvements with respect to efficiency and performance. Future regulatory and environmental requirements are not only driving still further improvements, but also extending the propulsion system efficiency through hybridization and potentially obsolescing the IC engine with hydrogen fuel cells. This paper describes the potential IC engine improvements to meet tomorrow’s challenges and the associated business and technical challenges in obtaining these challenges. The future propulsion system portfolio mix will encompass gasoline engines, diesel engines, hybrids and fuel cells. The critical role of the IC engine in this portfolio mix is examined.

An analytical spray model is described which can be used to calculate the penetration and trajectory of a spray in an engine combustion chamber with air swirl. The model consists of integral continuity and momentum equations written for a steady-state gas jet. The model contains adjustable entrainment and drag parameters evaluated from experimental data. A special single-cylinder, see-through engine and a schlieren optical system were used to study transient liquid fuel sprays under varied conditions. These experimental observations were used to determine appropriate values for the adjustable parameters in the spray model. Comparisons between model calculations and the experimentally observed sprays are presented for a wide range of conditions.

The authors examine the engineering requirements of a passenger car instrument panel having improved ability to reduce occupant injury. In the development of materials and their geometric configuration, the pad and its underlying structure receive primary consideration. A prototype instrument panel is described, and data are presented on approximately 40 different materials and combinations of materials evaluating their ability to absorb occupant energy.

This paper describes a study to determine the influence of preimpact vehicle braking on the positions and postures of unrestrained, children in the front seat at the time of collision. Anesthetized baboons were used as child surrogates. The unrestrained animals were placed in various initial sitting, kneeling, and standing positions typically assumed by children while traveling in automobiles. Tests were conducted with various front seat positions and seat covering materials. Measurements were made of pertinent vehicle dynamics and surrogate kinematics during the hard braking event. For each initial condition evaluated, a photosequence is given showing typical positions and postures of the surrogate during the braking event.

The new lightweight DA-6 Automotive Air Conditioning Compressor and Clutch Assembly is the lightest weight, most versatile 164 cc displacement compressor available today. It was designed and developed by General Motors which has produced over 72,000,000 compressors beginning with a 26.3 Kg rotary in 1953. In 1961, the 15.1 Kg six cylinder axial design was introduced and still remains a standard for the industry. A lighter weight 8.1 Kg radial four started production in 1974 and in 1982 the lightweight 5.7 Kg DA-6 will be introduced.

Prior to nationwide installation of evaporative emission controls in 1971, a significant quantity of hydrocarbon vapors was lost from fuel tank vents during vehicle operation. Earlier published quantifications of that emission source mode were based on test protocols which predated and differed significantly from the now well established 1975 Federal Test Procedure for regulatory emission measurement. This paper reports the results of a series of running loss evaporative emission tests on a fleet of 1970 cars. The testing was designed to provide experimental data under conditions consistent with the regulatory test. Uncontrolled baseline values of 6.7 g (0.9 g/mi) for 1970 cars and 6.0g (0.8 g/mi) for 1960 cars are consequently proposed as benchmarks from which to measure the extent of evaporative emission control accomplished by today's automobiles

A method for structural analysis using cast plastic scale models is presented. The method was used to predict the dynamic structural response of a vehicle powertrain using one-half scale cast Polyurethane models of the engine block and transmission case. The results of the model test program allowed the design to be modified to meet structural objectives before tooling commitments were made.