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Presented herein are the results of analyses of single-vehicle-accident tripped-rollover maneuvers involving eight light vehicles from four classes of ground vehicles. In particular, the minimum rollover velocities of vehicles encountering soil and curb terrain discontinuities in non-tracking situations are correlated with various vehicle-design parameters. All of the vehicles, except for the passenger cars, are analyzed in both unladen and laden states. The minimum rollover velocities for the vehicles in the various maneuvers and states of lading are generated with a 14 degree-of-freedom computer model which was validated using experimental tripped-rollover maneuver results.

Airport land planning commissions often are faced with determining how much area around an airport is affected by the sound exposure levels (SELs) associated with helicopter operations. This paper presents a study of the effects changing the size and composition of a microphone array has on the computed SEL contour (ground footprint) areas used by such commissions. Descent flight acoustic data measured by a fifteen microphone array were reprocessed for five different combinations of microphones within this array. This resulted in data for six different arrays for which SEL contours were computed. The fifteen microphone array was defined as the “baseline” array since it contained the greatest amount of data. The computations used a newly developed technique, the Acoustic Re-propagation Technique (ART), which uses parts of the NASA noise prediction program ROTONET. After the areas of the SEL contours were calculated the differences between the areas were determined.

An experimental and analytical study was conducted to investigate the effects of load control with port throttling on stability and fuel consumption at idle. With port throttling, the pressure in the intake port increases during the valve-closed period due to flow past the throttle. If the pressure in the port recovers to ambient before the valve overlap period, back flow into the intake system from the cylinder is eliminated. This allows increased valve overlap to be used without increasing the residual mass fraction in the cylinder. Results showed that, with high valve overlap and port throttling, idle stability and fuel consumption can be maintained at values associated with low overlap in a conventionally throttled engine. However, implementation of this concept in production is regarded to require precision-fit and balanced port throttles, an external vacuum pump for vacuum systems support, and revision of the PCV system.

Maintaining stability in the variator control system after quick torque changes is an important factor in achieving smooth mode changes in a power-split CVT system. In this paper, the ratio-changing characteristics of a half-toroidal CVT variator with hydraulic and mechanical loading devices are analyzed using a newly developed analytical model under dynamic load transmission. The ratio-changing characteristics of a variator with a mechanical loading device show a large overshoot after quick torque changes. In the case of a hydraulic loading device under constant application of axial pressure, it has been demonstrated that the ratio-changing characteristics are stable both theoretically and experimentally.

In order to achieve predictable handling of a race car, local mounts connecting suspension components to the chassis should be sufficiently rigid to minimize unwanted local deflection which may adversely affect suspension geometry. In this work, the effects of local chassis flexibility of the spring perch on roll stiffness, tire camber change, and steer angle change are determined from a finite element model (FEM) of a Winston Cup race car. Details such as side gussets, supporting brackets, and local curvature of the frame rail spring pocket are included in a shell model of the spring perch. The local shell model of the spring perch is integrated with the global finite element stiffness model of the chassis and suspension consisting of an assembly of beam and shell elements. A parametric study on the effects of thickness changes for seven different areas of the spring perch has been performed.

Operating characteristics including ignition limits, cyclic variability, and exhaust emissions were studied in the combustion of natural gas in a spark ignition, single-cylinder, variable compression ratio engine, operated at intake mixture temperatures ranging between 120 and -60 F. The work confirmed in general the feasibility of using natural gas in a spark ignition engine operated under extremely cold intake temperature conditions. It was learned that both the maximum peak cylinder pressures and the mass of mixture inducted by the engine increased as the intake mixture temperature was lowered, and that the emissions of pollutants were not significantly increased. These findings are thought to be particularly relevant to the use of natural gas in spark ignition engines, either as LNG or under very cold wintry conditions.

Lift and pitching moment coefficients are determined for a symmetrical NACA 0012 and an asymmetrical NASA LS(1)-0417 for free stream turbulent intensities, urms /U equal to 0.005 and 0.015. The tests are performed at Reynolds numbers based on chord length equal to 150,000 and 500,000 in an open return, closed test section type wind tunnel. Velocity information is obtained via laser Doppler and hot wire anemometry techniques. The lift coefficients, Cℓ for both airfoils decrease approximately 15% at each angle of attack at the higher turbulence level. The maximum Cℓ, however, is increased as is the stall angle. Also, the pitching moment coefficients became more positive with respect to the quarter chord. The integral scale of the free stream turbulence is approximately 1.5 cm.

The U.S. Environmental Protection Agency has recently reduced the permissible concentration of lead in gasoline from 1.1 to 0.1 gram per gallon, and has proposed to eliminate lead entirely by 1988. In addition to its octane-enhancing properties, lead in gasoline protects exhaust valve seats in older engines from undue wear (“valve-seat recession), and it and its scavengers have numerous other positive and negative effects. These include changes in octane requirements, hydrocarbon emissions, engine rusting, corrosive wear, oil thickening and degradation, spark-plug fouling, exhaust-valve burning, and exhaust system corrosion. This paper reviews the literature on the harmful and beneficial effects of lead and lead scavengers on engines, and examines some of the substantial body of operating experience that has been accumulated with unleaded gasoline in older engines.

An investigation of the effects of lubricant composition changes on spark ignition engine wear and deposits when using alcohol fuel was jointly sponsored by the U.S. Department of Energy and the U.S. Army Mobility Equipment Research and Development Command. In the work covered by this paper, tests were conducted with methanol fuel in a 2.3-liter engine using a modified ASTM Sequence V-D procedure. The baseline lubricant was a 10W-30 grade product, qualified under MIL-L-46152, for which a large amount of field and laboratory data were available. Eleven variations of the baseline lubricant were supplied and tested. The results indicate that a magnesium-based detergent additive was less effective in controlling methanol-related engine wear than was a calcium-based additive. Ashless dispersant chemistry was also determined to be of importance in controlling wear with methanol fuel.

Some of the factors influencing the introduction of mandatory seatbelt use in Great Britain are outlined. The effectiveness of seatbelts is considered. Pre- and postlaw seatbelt use rates are described. The reductions in frontseat car occupant casualties following the introduction of the law are reported, and it is noted the actual reduction in fatalities is in line with the expected reduction. The results of the time series analyses of all road accident casualties are presented. These analyses indicate, with the data currently available, the changes in the numbers of other road users injured and killed cannot be attributed to the effects of the seatbelt legislation but are in line with normal seasonal and annual fluctuations. A brief review is made of studies relevant to the debate on risk compensation, and it is concluded that available evidence indicates that risk compensation probably does not occur when drivers are compelled to wear seatbelts.

The supporting flange for a wet liner in a diesel engine was analyzed. The results show that stresses can vary as much due to manufacturing tolerance bands as due to major dimensional changes in the joint area. Guidelines have been developed for selecting fillet radii and for the size and shape of the contact area between the liner and block. Further, the paper shows that analytical methods can be used to aid the designer in determining not only the basic dimensions but also the tolerances. The analytical techniques also allow “trial and error” comparison of slight variations in design more easily than by testing. Detail evaluation can be accomplished with this analytical approach that is difficult, if not impossible, to accomplish with available experimental methods.

The introduction of Worldwide harmonized Light vehicles Test Procedures (WLTP) in Europe and increased Corporate Average Fuel Economy (CAFE) standards in the United States for fuel economy and emissions reductions are going to have a larger role in vehicle development. Two major ways to increase fuel economy and reduce emissions are by reducing mass and improving aerodynamics. In the wheel segment, these two possible means to improve fuel economy compete against each other. Most lightweight wheel designs are detrimental to aerodynamics and aerodynamic wheels are seen as unstylish and with a high mass penalty. One solution is through the use of composite wheel technology which replaces non-structural aluminum with lighter weight materials. This study used SAE J2263 and SAE J2264 procedures to establish baseline fuel economy numbers and to evaluate various mass, inertial and aerodynamic differences between wheel concepts.

This paper continues a previous study of the effects of uncertainty of measurement upon accident reconstruction. The task is to identify, given the many inevitable errors of observation, the few of greatest import, so that these errors may be reduced, and to document the accuracy of the associated reconstruction. Until recently, it was not for lack of method that such studies could not be properly performed, but for lack of good data on uncertainty of measurement. The essential data was provided in 2002 in a report by Bartlett and others of juried studies performed by volunteer field investigators, summarized and supplemented in 2003 by Bartlett and Fonda in the form of a single table of all likely errors of measurement (furnished again here). In that paper, Finite Difference Analysis (FDA) was reviewed and with the aid of the new data was applied to automotive accident reconstruction.

Nitrogen finished galvanized steel and other grades of zinc coated steels with little or no zinc-iron alloy layer have been found to accept normal metal finishing techniques without adversely affecting their pretreating or painting characteristics. The finished surface is comparable in appearance to a painted cold rolled steel surface. The durability and corrosion resistance of the painted metal finished surface from which all zinc has been removed is equivalent to that of painted cold rolled steel. Grades with appreciable zinc-iron interfacial alloy in the coating micro-structure can be a problem when the alloy is exposed by metal finishing. Iron-zinc surfaces have a tendency to cause cratering in electrocoat primers.

A single cylinder carburetor SI engine with a modified L type cylinder head and equipped with a fuel injector was used to inject methanol into the combustion chamber. Four series of runs at an engine speed of 2500 rpm were made. One series with different values of λ* was performed with gasoline, and the other three series methanol was injected into the gasoline-air mixture. Each series of methanol injected run was supplied with the same energy input per cycle to correspond to that of the gasoline. The results of the experiments indicated that the performance (BHP) of the engine was proportional to the energy input of the mixture up to about 50% methanol injected. With the equivalence air-fuel ratio above λ = 1.15 (lean mixture), it was found the NOx concentration decreased more than 30% while the BSFC remained constant.

This experimental study was conducted in a motored research engine to investigate the effect of blending methanol and ethanol on hydrocarbon oxidation and autoignition. An 87 octane mixture of primary reference fuels, 87 PRF, was blended with small percentages of the alcohols to yield a constant gravimetric oxygen percentage in the fuel. The stoichiometric fuel mixtures and neat methanol and ethanol were tested in a modified single-cylinder engine at a compression ratio of 8.2. Supercharging and heating of the intake charge were used to control reactivity. The inlet gas temperature was increased from 325 K to the point of autoignition or the maximum achievable temperature of 500 K. Exhaust carbon monoxide levels and in-cylinder pressure histories were monitored in order to determine and quantify reactivity.

This report presents the Auto/Oil AQIRP results of a methanol fueled vehicle emission study. Nineteen early prototype flexible/variable fueled vehicles (FFV/VFV) were emission tested with industry average gasoline (M0), an 85% methanol-gasoline blend (M85), and a splash-blend of M85 with M0 (gasoline) giving 10% methanol (M10). Vehicle emissions were analyzed for the FTP exhaust emissions, SHED diurnal and hot soak evaporative emissions, and running loss evaporative emissions. Measurements were made for HC, CO and NOx emissions and up to 151 organic emission species, including air toxic components. M0 and M10 emissions were very similar except for elevated M10 evaporative emissions resulting from the high M10 fuel vapor pressure. M85 showed lower exhaust emissions than M0 for NMHC (non-methane hydrocarbon), OMHCE (organic material hydrocarbon equivalent), CO and most species. M85 had higher exhaust emissions for NMOG (non-methane organic gases), NOx, methanol and formaldehyde.

It has been observed that a certain percentage of diesel particulate filters (DPFs) from the field form mid-channel ash plugs both in light duty and heavy duty applications. As revealed in a post mortem study, some field samples have ash plugs of 3-10 cm length in the middle of DPF inlet channels, which can potentially reduce the inlet channel volume by more than 50%. As a result, the mid-channel ash plug reduces the effective filtration area and decreases the effective channel open width in the middle of the channel. This explains why these filters are reported as having large increases in pressure drop. Moreover, the mid-channel ash deposits reduce the DPF service life and render the filter cleaning process ineffective. In the present study, an open source CFD tool is applied to study the 3D flow crossing two representative inlet and outlet DPF channels where the inlet channels have mid-channel ash plugs.

Vehicle suspension systems that adopt Hotchkiss layout are commonly based on leaf springs. For better comfort for passengers, some features such as rubber pads are used on the springs to reduce noise from metallic contact between leaves, but those pads can compromise the durability of the spring if not well designed or located in the spring assembly, as we will demonstrate on this paper. To do so, it will be presented comparisons using CAE methodology and physical parts test results from vehicle and bench testing which were loaded in different conditions to demonstrate how the rubber pad position can influence the durability of the spring, especially near the eyelet region for some specific load conditions. The case studies presented here are focused on the impact of the rubber pads on durability life of springs, but not defined as root cause of failures.

Previous research in our laboratory has shown that NOx emissions can be sharply reduced by PREDIC (PRE-mixed lean DIesel Combustion), in which fuel is injected very early in the compression process. However some problems still remain, such as higher fuel consumption, a lack of ignition timing control, and a large increase in THC and CO, compared to conventional diesel combustion. Appropriate mixture formation is necessary to solve these problems. In this paper, the influence of mixture formation on PREDIC was investigated. It was found that the pintle type injection nozzle was shown to be suitable for PREDIC, because it produced a comparatively uniform mixture in the combustion chamber and avoided collision of the fuel spray with the cylinder liner. Modeling by the KIVA-II software package was carried out to improve our understanding of the mixture formation process.