Viewing 110701 to 110717 of 110717
Technical Paper
Krzysztof Prażnowski, Jaroslaw Mamala
Abstract The vibrations of the sprung mass of a passenger car, traveling along a road surface, are random. They also form its main source but there are besides other factors to consider. The resulting force ratio is overlapped by other phenomena occurring at the interface of the pneumatic tire with the road surface, such as non-uniformity of tires, shape deformations and imbalances. The resulting additional inertia force acts on the kinematic force that was previously induced on the car body. The vibrations of the sprung mass of the car body at the time can be considered as a potential source of diagnostic information, but getting insight their direct identification is difficult. Moreover, the basic identification is complicated because of the forces induced due to the random interference from road roughness. In such a case, the ratio defined as SNR assumes negative values.
Technical Paper
Frank Borik
A laboratory test was developed to evaluate materials for their resistance to low-stress abrasion. The abrasion is caused by a silica sand slurry conveyed between the specimen and a 7 in. diameter steel wheel, having a neoprene rubber rim, rotating at a speed of 240 rpm. The specimen is pressed against the wheel with a force of 50 lb. The wear test was used to determine and to compare the abrasion resistance of a variety of materials ranging from constructional steels to sintered carbides. The effects of test variables, metallurgical variables, and reproducibility of results are discussed. The test proved to be highly reproducible.
Technical Paper
Rubens Cioto, André Renato Collares, César Henrique Zuffo, Luiz Roberto Marins, Wilsimar do Carmo Silva
For decades, automotive connecting rod were fabricated machining separately the cap from the body, with precision to maintain accurate alignment, being that the fixing was by the use of special screws, with grinded body to remain perfectly adjusted in passage holes, aiming this way prevent possible lateral displacements. From the end of the last century, due to new technologies in the production and use of special microalloyed steels such C7056BY, permitted to introduce in the market connecting rods made of a single part, using the method of fracture splitting process to separate the cap from the body of the connecting rod. This technique provided gains as weight reduction and consequently reducing noise and vibration due to the decrease of the oscillating mass from the system. By the literature is estimated cost savings of up to 25%, and better fatigue performance.
Technical Paper
Charles Y. Warner, Charles E. Stother, Michael B. James, Robin L. Decker
The National Highway Traffic Safety Administration (NHTSA) has recently opened a rulemaking docket seeking comments on the design of automobile seats and their performance in rear Impacts. There are two philosophies of seat design: one advocates rigid seats, the other advocates seats which yield in a controlled manner. A review of the legislative history of seat back design standards indicates that yielding seats have historically been considered a better approach for passenger cars. The design characteristics of current production automobile seats are evaluated and show no significant changes over the past three decades. Concerns about the performance of rigid seat backs in real world rear impacts are discussed, specifically increased injury exposure due to ramping, rebound and out-of-position occupants.
Technical Paper
Michael B. James, Charles E. Strother, Charles Y. Warner, Robin L. Decker, Thomas R. Perl
Recent detailed field accident data are examined with regard to injuries associated with rear impacts. The distribution of “Societal Harm” associated with various injury mechanisms is presented, and used to evaluate the performance of current seat back and restraint system designs. Deformation associated with seat back yield is shown to be beneficial in reducing overall Societal Harm in rear impacts. The Societal Harm associated with ejection and contact with the vehicle rear interior (the two injury mechanisms addressed by a rigid seat approach), is shown to be minimal. The field accident data also confirm that restraint usage in rear impacts has a substantial injury-reducing effect. Laboratory tests and computer simulations were run to investigate the mechanism by which seat belts protect occupants in rear impacts.
Journal Article
Hong Liu, Jiajia Jin, Hongyu Li, Kazuo Yamamori, Toyoharu Kaneko, Minoru Yamashita, Liping Zhang
Abstract It has been long established fact that fuel economy is a key driving force of low viscosity gasoline engine oil research and development considered by the original equipment manufacturers (OEMs) and lubricant companies. The development of low viscosity gasoline engine oils should not only focus on fuel economy improvement, but also on the low speed pre-ignition (LSPI) prevention property. In previous LSPI prevention literatures, the necessity of applying Ca/Mg-based detergents system in the engine oil formulations was proposed. In this paper, we adopted a specific Group III base oil containing Ca-salicylate detergent, borated dispersant, Mo-DTC in the formulation and investigated the various effects of Mg-salicylate and Mg-sulfonate on the performance of engine oil. It was found that Mg-sulfonate showed a significant detrimental impact on silicone rubber compatibility while the influence from Mg-salicylate remains acceptable.
Technical Paper
Sławomir Dzierzek
The paper presents the results of an experiment-base modeling of a typical cylindrical rubber bushing used in wheel suspension mechanisms. The aim of the study was to build a bushing model which emulates its stiffness and damping behavior in the full range of static and dynamic loads, which are specific to automotive suspensions.The model developed maintains relative simplicity making it suitable for fast, large-scale dynamic simulations and requires a reasonable number of tests to determine its parameters. A procedure for the identification of model parameters is outlined in the paper, and a typical application of the model, the simulation of forced spatial vibration of a wheel carrier in an independent wheel suspension, is presented.
Technical Paper
Biljana Mikijelj, John Mangels, Edwin Belfield, Andrew MacQueen
The need for more efficient diesel engines combined with increasingly stringent emissions standards have resulted in increased cylinder operating pressures and fuel injection pressures. These conditions result in higher contact stresses in key components, which can result in wear, galling, micro-welding and finally failure of metal components. New material options are required to solve these problems. Silicon nitride has unique tribological and physical properties (low mass combined with high strength and contact fatigue resistance) that allow its use under high contact stresses. Selection of appropriate grade of silicon nitride can solve problems in the valve train and the fuel delivery systems for light and heavy-duty diesel engines.
Technical Paper
Dale R. Tree, Paul D. Wiczynski, Thomas M. Yonushonis
Measurements have been made to determine the effect of piston crown surface properties on combustion. Back-to-back engine tests were conducted to compare surface modified pistons to a production piston. Each modified piston was found to prolong combustion duration. Porous coatings and a non porous, roughened piston were observed to increase fuel consumption. Increase in fuel consumption was determined to be the result of increased heat release duration. The data show surface roughness alone affects the duration of heat release. The shift in magnitude of the centroid of heat release was similar to the shift observed in insulated engine experiments.
Technical Paper
S. D. Heron
FUELS for use in aircraft engines are discussed with reference to their antiknock value, volatility, vapor-locking and engine-starting properties, gum content and availability, and to antiknock agents. The usefulness of a fuel for spark-ignition engines is stated to be limited by its tendency to heat the cylinder and the piston unit. Definite evidence is available that the tendency of fuels to heat the cylinder unit is not always in accord with their tendency to cause audible knocking. The fuel required depends upon the compression ratio of the engine, its volumetric efficiency, the design, size and temperature of the cylinder unit, and the rate of revolution. Mid-Continent Domestic Aviation gasoline having an approximate antiknock value of 50 octane-50 heptane gives excellent results if the engine output is kept within the limitations of this fuel but is not suitable for many modern aircraft engines if flown wide open at sea level.
Technical Paper
Richard A. Demmin, Fred Girshick, Alan M. Schilowitz
Two programs were conducted to study the relationships between engine oil rheology and crankshaft bearing wear. A Chassis Dynamometer test of four oils in four cars was used to explore and define the key variables affecting bearing wear. These results were used to design a Field Test of nine oils in 45 taxicabs in New York City. The test oils (SAE OW-20 to 20W-20) were formulated to measure the effects of viscosity, viscosity index improver, and detergent inhibitor package. Bearing wear tended to be either low and unremarkable or very high, particularly in the thrust bearings. Oil performance was best expressed as the frequency of excessive wear, rather than by quantitative wear measurement. There were many instances of very high wear in cabs operated with the lowest viscosity oils but none in cabs with higher viscosity oils.
Technical Paper
P.I. Lacey, S. Gunsel, M.D. Ferner, M. Pozebanchuk, A Alim
The average oil change interval for passenger vehicles in the USA is gradually increasing, and is currently approaching 8,320 km (5,200 miles). This paper details the results of lubricant condition monitoring on samples taken from hundreds of vehicles at intervals ranging from 0 to 25,600 km (16,000 miles). The data indicate steady additive depletion by 4,800 to 9,600 km (3,000-6,000 miles), resulting in a concomitant decrease in measured oxidation resistance. Oxidation and nitration of the basestock was also found to be present at this point, resulting in a gradual increase in both kinematic and HTHS viscosity. As a result, it is predicted that excessively long drain intervals will produce a measurable increase in fuel consumption and associated CO2 emissions. Many owners' manuals recommend service intervals of 12,000 and 4,800 km (7,500 and 3,000 miles) under “normal” and “severe” service conditions, respectively.
Technical Paper
Akira Ono, Satoru Kurimoto, Toshiaki Kawachi, Katsuya Arai, Toshiaki Kuribayashi
Properties of engine bearings were investigated with different bearing materials and different HTHS viscosity oils by means of both an engine test and a rig test. The rig test well simulated the bearing wear which occurred in the engine test. Lead-bronze bearings with lead-tin-indium overlay gave the least amount of wear in operating under high speed and heavy load conditions even with low HTHS viscosity oil. Aluminum bearings without overlay gave good wear resistance in the case of no seizure occurrence. The wear amount of bearings were well correlated with HTHS viscosity, not with kinematic viscosity.
Technical Paper
Toshihide Ohmori, Mamoru Tohyama, Masago Yamamoto, Kenyu Akiyama, Kazuyoshi Tasaka, Tomio Yoshihara
The influence of engine oil viscosity on the wear of piston rings and cam faces has been investigated by fired engine tests using a radioisotope (RI) tracer technique. High-temperature and high-shear-rate (HTHS; 150°C, 1O6 s-1) viscosities of the experimental oils prepared are 2.2, 2.4, 2.6 and 3.1 mPa•s. At an oil temperature of 90°C the wear of piston rings and cam faces did not increase, even if the HTHS viscosity was lowered down to 2.2 mPa•s. However, both piston rings and cam faces exhibited an increase in wear below 2.4 mPa•s at 130°C. It was also recognized that valve train wear did not significantly increase with reducing viscosity in the motored engine tests at a temperature of 50°C. From these test results, it was suggested that the oil with the HTHS viscosity of 2.6 mPa•s sufficiently demonstrates the antiwear performance equivalent to that with around 3.0 mPa•s for application to piston rings and cam faces.
Journal Article
Sumit Basu, Matthew Henrichsen, Pushkar Tandon, Suhao He, Achim Heibel
A simple 1-dimensional filter model, with symmetric and asymmetric channels, has been developed to investigate the fundamental behavior and performance of ceramic partial diesel particulate filters (PFs). The governing equations of mass and momentum are similar to those of a full DPF [7, 15]. A standard DPF with the plugs at its inlet face removed has been referred to as a ‘rear-plugged PF’ while, one with the plugs at the outlet face removed has been referred to as a ‘front-plugged PF’ in the present study. Removal of some of the plugs from a standard ceramic DPF reduces the (i) overall pressure drop (ΔP) across the filter, (ii) filtration efficiency (FE) of the DPF, and (iii) manufacturing cost. Partial filters stand a high chance of being deployed in diesel exhaust after-treatment systems for the emerging markets (Brazil, Russia, India, China) that follow Euro 4 emission regulations.
Technical Paper
M.G.L. Cresswell, P.B. Hertz
Until recently, the aerodynamic design of large transport trucks has often ignored an important contribution to drag caused by the accessory rearview mirrors. In this study, three commercially available truck mirrors are tested full-scale in a wind tunnel at highway speeds. The actual drag forces and the coefficients of drag based on frontal and glass areas are compared for various mirror angles, with and without a convex-mirror attachment. All three mirror types produced significantly high drag forces which were used to estimate the fuel consumption attributed to mirror aerodynamic resistance. A standard rearview mirror, with mounting brackets, set was found to exhibit a drag coefficient, based on the glass area, of 1.81, which would increase the drag of a typical (Cd = 0.7, Af = 4.5m2) truck by about 8.5 percent.
Technical Paper
James A. Ennis
The reason for the inclusion of the word "business" in the title is self-explanatory. For us to be competitive in the world market, we must look at all aspects of the molding and thermoplastic components. We all know that molding involves more than pushing a cycle button. Packard Electric has several hundred molding machines, and I would like to share with you an insight into our total operation, including the checks and balances used to mold a quality part at the lowest possible cost. The presentation will include our design, processing and validation of both to meet our customers' demands in a product. Then we will move into the production phase and discuss our receiving inspection of material, our manufacturing process controls and final release mechanism for the distribution of product. I'm sure most of you are aware of the "parts" of the molding operation.
Viewing 110701 to 110717 of 110717


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