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Viewing 70801 to 70830 of 104525
1988-10-01
Technical Paper
881596
M. G. Henk, G. H. Hilbers
A brief review of a variety of Inspection/Maintenance programs is provided. The costs and benefits of several of these programs are discussed. The effects of vehicle operating parameters on the performance of the catalyst in the exhaust system of the vehicle are discussed in detail. Key variables for catalyst performance are light-off performance and exhaust temperature and air/fuel ratio. The relative effects of common causes of catalyst deactivation on control of HC, CO and NOx are also discussed.
1988-10-01
Technical Paper
881599
Morrie Kirshenblatt, Matthew A. Bol
If diesel fuel is to be replaced with methanol in compression ignition engines, the differences in methanol's properties could be considered advantageous, neutral or nonadvantageous. Of 26 properties studied, only lubricity, critical temperature, flame luminance and odour were identified as amenable to modification through fuel additives. Testing was then performed to individually examine the effect of selected additives on luminance and odour. Butanethiol was identified as a promising malodourant, offering a relatively strong odour at a low concentration. Flame luminosity testing failed to identify any additive applied in low concentrations, that could raise the average luminance of methanol to anywhere near gasoline.
1988-10-01
Technical Paper
881602
John Abraham, F.V. Bracco
The first comparisons of measured and computed mean velocities, and of measured fluctuation intensities and computed turbulence intensities in a motored rotary engine are presented. The computations were performed with a recently developed three–dimensional model. The measurements were made at the Sandia National Laboratories by Dimpelfeld and Witze at several locations along the rotor housing and at two engine speeds. The measured and computed mean velocities agree to within 15% whereas the computed turbulence intensities correctly are lower than the measured fluctuation intensities by about 30% to 50%, as anticipated. Under motored conditions, the turbulence intensity tends to be rather homogeneous and of similar magnitude somewhat before and after top dead center but significantly inhomogeneous and of greater magnitude around top dead center. The comparisons suggest that predictions of mean gas velocity and of turbulence intensity can be made with the available model.
1988-10-01
Technical Paper
881601
L.J. King, G.B. Hamilton
The question of whether methanol-fuelled engines can provide needed reductions in output of regulated exhaust pollutants without corresponding increases in formaldehyde levels is still not clearly answered. If ongoing engine development fails to bring formaldehyde down to diesel or gasoline engine levels, or if aldehyde output is separately regulated, catalytic exhaust after-treatment could be required for methanol-fuelled engines. This paper provides an overview of current industry philosophies, research work and testing regarding catalytic converters for methanol fuel, with particular emphasis, on applications for heavy duty compression-ignition type engines.
1988-10-01
Technical Paper
881546
Robert McCormick, Bret Yetter
The transition from the current Shuttle Space Transportation System (STS) payload delivery capability to an advanced launch system has been the topic of several studies and proposals. The need for an early, reliable, low cost heavy lift vehicle has been identified and supported by NASA as a response to that need. This paper will provide a brief background and description of the Shuttle-C, and will primarily focus on cargo bay sizing and manifesting for one of the three identified design reference missions: Space Station Freedom assembly.
1988-10-01
Technical Paper
881547
Sheryl L. Chappell
Pilots' use of the traffic alert and collision avoidance system (TCAS II) was evaluated in simulated air carrier line operations. Sixteen three-person airline flight crews currently flying the Boeing 727 served as subjects. Each crew flew eight flights with or without TCAS as part of the full-mission simulation. Their performance of the avoidance maneuvers and evaluation of the system were measured. The crews were trained on the aircraft differences and the TCAS II. The second day consisted of a 10 hour duty day of normal line operations. All communications, navigation, and cockpit procedures were carried out according to the standards of their particular airline. The crews were under full air traffic control along with the other aircraft in the airspace. All crews were exposed to the same traffic conflicts under the same conditions of high/low traffic densities, high/low workload, high/low visibility. Pilot flying and dusk/night lighting were counterbalanced.
1988-10-01
Technical Paper
881548
Berton E. Beach
There have been some air carrier concerns that basic aviator skills are atrophying due to the increasing use of automation in all phases of airline operation. We will examine three systems where automation has greatly influenced crew activity, outline our concerns, and discuss how we are addressing those concerns.
1988-10-01
Technical Paper
881576
Donald J. Smolenski, Stephen P. Bergin
The ASTM Sequence IIID engine-dynamometer test has been used to evaluate the high-temperature protection provided by engine oils with respect to valve train wear, viscosity increase (oil thickening), deposits, and oil consumption. The obsolescence of the engine used in this test along with the need to define even higher levels of performance associated with a new oil category (SG) prompted efforts at developing a replacement test. This paper describes the hardware and procedure development of this replacement test, the ASTM Sequence IIIE test. Test precision and correlation with field and Sequence IIID results on a series of reference oils is also discussed.
1988-10-01
Technical Paper
881579
Denis C. Roberts
European engine oil requirements differ from those of North American. The paper reviews the current European passenger car and commercial vehicle service fill requirements. These are largely built on a core of ASTM tests but with additional European test requirements to cover specific performance areas not addressed or not adequately covered by API Service Station and Commercial Service categories. Recent and expected changes on the European scene are discussed and a look is taken at the future.
1988-10-01
Technical Paper
881580
R. T. Graf, W. G. Copan, R. E. Kornbrekke, J. P. Murphy
The relationship of engine test sludge to field sludge was investigated by a variety of analytical techniques. Engine oil drains and sludges are suspensions of aggregated, resinous particles in oil. The sludges, in particular, contain large particle networks which are readily broken under shear. The resinous phase itself contains highly oxidized fuel fragments, and is enriched in aromatics, acidic species, and additive elements relative to the hulk oil. Field sludge and drain oil samples from the U.S., Europe, and the Far East are shown to be chemically similar to sequence VE engine test sludge and drain oil. Fleet test drain oils from vehicles powered by the Daimler Bens M102E engine are shown to be chemically similar to M102E engine test drain oils. The VE test is different from the M102E test: the VE engine test emphasizes the build-up of nitro-oxidized fuel fragments in the drain oils, compared to the M102E test which emphasizes the build-up of fuel residue in the drain oils.
1988-10-01
Technical Paper
881581
J. B. Hanson, S. W. Harris, C. T. West
In the Sequence VE test, combustion-derived contaminants provide the dominant stress on the lubricant's ability to maintain engine cleanliness and prevent wear. Contamination levels in the Sequence VE test are as much as twice as high as in the Sequence V-D. This is accomplished by hardware and operational design, and is demonstrated by analysis of used-oil contaminant levels. The control of sludge deposits by dispersants is essentially a stoichiometric process. The VE test responds very well to increased dispersant treatment in proportion to the increased contaminant load. Chemical analyses of the blowby gases and used VE engine oils offer insight into mechanisms by which engine sludge and wear are generated. Acidic species in the oil appear to play a major role. VE wear also contributes to establishing sludge severity, but this can be avoided by controlling wear with the proper balance of conventional inhibitors.
1988-10-01
Technical Paper
881582
M. Tayeb Benchaita
This paper reports a lubricant study conducted on a Caterpillar 1Y540 single-cylinder engine test equipped with a 34068 truck production piston. The sequence test, run under well controlled conditions for a large number of CE and CD+ diesel oils, shows a good discrimination of the lubricant for oil consumption and piston deposits and similar to that given by new North American multicylinder engine tests utilizing LTL pistons. Owing to its excellent reliability, adequate severity, and availability of hardware parts, this engine test provides a suitable alternative for replacement of the Caterpillar 1G2 and EMA SCOTE-1.
1988-10-01
Technical Paper
881583
Philip R. Shore
The oil consumption of a turbocharged, aftercooled direct-injection truck diesel engine was measured using a tritium-tracer technique. The advantages of the method over other chemical and radioactive tracers are described, and supplemented with data from radioanalysis of tritiated oils. As a proportion of fuel consumption, the oil consumption was shown to range from <0.1% to >0.4% depending upon the engine's load and speed, with the highest consumption at idle and at full load conditions. The mass consumption rate ranged from 6 g/h at light load, low speed to 230 g/h at full load, rated speed. The contribution of consumed oil to another truck engine's particulate-bound hydrocarbon emission was shown to be greatest at light and intermediate loads and negligible at high loads. The implications of these observations on diesel particulate control are discussed.
1988-10-01
Technical Paper
881881
Robert D. Hillebrand
Abstract Lear Siegler Truck Products Corp. has improved the design of their Neway height control valve (HCV) for use with truck, bus, and trailer air suspensions. This improvement applies a patented method for developing the time delay feature. Air suspension applications in the commercial, military, and recreational segments of the vehicle market have recorded sustained growth. Vehicle air suspensions as well as air suspended cabs, seats, and kingpins are increasingly specified options. At least one HCV is required on every air suspension system. The HCV will automatically control the design height reliably for several years. The main objectives for the valve improvements were: to increase durability, reduce sensitivity to misinstallation, and improve manufacturability. This paper will deal with the design, development, and testing of the improved Neway HCV.
1988-10-01
Technical Paper
881878
Nobuo Kobayashi, Minoru Yamada
One-box type vehicles are especially liable to a loss of stability when entering a region of cross-wind. The reasons for this instability were investigated using scale models and by means of a mathematical simulation. Results indicated that yawing moment attains a peak at a precise position of the vehicle relative to the cross-wind. Visualization of the air flow and measurement of the pressure distributions established the cause of the phenomenon. Furthermore a study was conducted into the effects of body shape on stability and the efficacy of various modifications was assessed.
1988-10-01
Technical Paper
881880
Bruce A. Purkey, Elihue Ackerson
This paper will discuss the methodology historically used to select the charging system for commercial vehicles. It will detail both the design and operating principles of a new recording device that records actual vehicle electrical load during vehicle operation. It also covers data manipulation through computer simulation to determine exact needs, plus identify and address problem application.
1988-10-01
Technical Paper
881877
Olga J. Pendleton, Rodger J. Koppa, Ofelia Gonzalez-Vega
Methods for reducing and analyzing the measurements made of splash and spray from heavy trucks using laser transmissometers have been under study for the past decade. Approaches have ranged from simple selection of spray density data with no corrections for wind direction and velocity to elaborate “normalization” approaches. None of these approaches have assisted in predicting what a given aerodynamic configuration will produce under wind conditions that have not actually been investigated. This paper describes an approach to such prediction based on a regression model that was developed from well over 100 observations made on one configuration under a wide variety of different wind conditions. The model is then applied to recent test results to illustrate its utility in making splash and spray evaluations more generalizable to real-world conditions.
1988-10-01
Technical Paper
881875
M. E. Olson, P. R. Fry
The application of aerodynamics to treat highway tractor-trailer vehicles, primarily for fuel economy gains, has a potentially significant effect in reducing the spray generated from surface water at high road speeds. This paper describes the evaluation of an aerodynamically designed conventional tractor-trailer system to determine the levels of spray control assignable to individual aero features. Basic study involved vehicle operation through controlled water depths using laser instrumentation to rate the level of spray generated. Additionally, video documentation of certain configurations operating on-highway compared the real world effectiveness of aerodynamic designs in moderate rainfall.
1988-10-01
Technical Paper
881874
Timothy T. Maxwell, Jesse C. Jones, William B. Jones
Students and faculty of the Mechanical Engineering Department at Texas Tech University have developed two add-on devices that can significantly reduce pickup truck drag without limiting vehicle utility. One device is a wing structure mounted behind the top rear of the cab; the other device is a cover over the rear portion of the pickup bed. Both devices have demonstrated 5% to 6% drag reductions. Further, the rear bed cover reduces vehicle lift by 30%. Most significant, scale model tests have indicated drag reduction on the order of 17% and lift reduction of 30% when the wing and bed cover are used together. Work to date has involved scale model tests in a low speed wind tunnel and full scale tests in the Lockheed wind tunnel. In addition, computational fluid dynamic studies have been performed to aid in designing the test program and interpreting the test results.
1988-10-01
Technical Paper
881873
I. Kemp
Testing of truck tyres of a 3/6 rib pattern configuration with varying degrees of even and uneven (one-shoulder) wear on a variety of road surfaces has shown a fairly consistent relationship between even and uneven worn tyres of similar pattern depths. When a wheel slip brake control system is operating, the relationship between the braking force of even and unevenly worn tyres is noticeably speed dependent. A wheel slip brake control system gives an improvement in overall vehicle retardation on all surfaces involved in the evaluation, which improvement may be speed dependent.
1988-10-01
Technical Paper
881872
Richard W. Harden
A study was conducted for the purpose of evaluating the effects of load and age on truck tire traction performance. A statistically designed experiment was utilized for this purpose. The general methodology of traction data analysis and presentation is given. A method of presenting traction data via a matrix, utilizing the concept of Least Significant Difference is shown. This method provides a basis for better decision making. The results of the study indicate that load can have significant impact on truck tire traction. All aspects of dry traction are affected by load as is wet peak traction. Load was observed to have no significant effect on wet slide traction. Tire aging was found to have no significant effect on any aspect of truck tire traction.
1988-10-01
Technical Paper
881871
William C. Pierce
A New drive axle air suspension for commercial trucks and tractors has been developed by Neway Operations of Lear Siegler Truck Products Corp. to answer some of the most important issues facing the transportation industry today. This suspension, named the Air-Beam™, is the culmination of five years of research, development and testing, and effectively meets the industry needs for low installed cost, light weight, good ride and handling, and extended durability. This paper will outline the approach taken to design, test and produce this suspension.
1988-10-01
Technical Paper
881868
Lloyd M. Rinehart, Robert A. Novack
Abstract This paper presents a review of the core functions and decisions of transportation and traffic management in the automobile industry. Its purpose is to present the concepts within a revised framework which is set in a logistical channels context. Using this approach it easier to see the interdependence which is necessary between shippers and carriers that handle raw materials, component parts, and finished products.
1988-10-01
Technical Paper
881866
D. D. Furleigh, M. J. Vanderploeg, C. Y. Oh
This paper presents an analytical study of the performance improvements that can be obtained at both high and low speed using multiple steered axles on heavy articulated trucks. At high speed, rollover usually represents a worst case scenario. Therefore we have chosen to evaluate possible steering designs based on their ability to reduce lateral acceleration of the semitrailer center of gravity. This is in contrast to passenger cars where four-wheel steering has typically been evaluated based on measures that were thought to be related to driver acceptance. This paper also investigates the effects of steering rear tractor axles on the low-speed maneuverability of the vehicle. Steering algorithms for the rear tractor tires were evaluated using frequency response and simulation of an obstacle avoidance maneuver. Results indicate that at high speeds considerable reductions in trailer lateral acceleration can be obtained during transient maneuvers.
1988-10-01
Technical Paper
881867
Jules C. Guillemette
Increasing payloads on trucks and trailers, together with changing legislation for vehicle carrying capacities, are creating demand for trailers with multiple axles and widespread suspensions. The Self-Steering Axle eliminates tire scuffing on tight turns negotiated by these vehicles. It is a non-powered, self-centering axle that operates by natural trailing geometry and road friction.
1988-10-01
Technical Paper
881864
Jack R. Brace, Helmut Steiner
A possible solution to transfer weight from the Power Unit to the Trailer Unit would be to add a third axle to the trailer and remove one of the normal three axles of the Power Unit. This third trailer axle would be a self steering axle which would handle the increased trailer weight and at the same time reduce tire wear and increase trailer stability.
1988-10-01
Technical Paper
881862
Michael J. Reed, Mukesh R. Trivedi
Product design cycle time can be significantly reduced with the utilization of Computer Aided Engineering. (CAE) techniques. Computer modeling and analyses can eliminate portions of the lengthy procedure required by traditionally accepted Product Development Methods. This paper examines and compares a CAE application to a conventional method in the redesign of a structural component of a heavy-duty truck. The procedures to achieve design objectives: Modeling through stress analysis iterations and verification of analyses by prototype testing will be addressed together with the impact of such approach on cost and quality of engineering.
1988-10-01
Technical Paper
881861
P. G. Gerardot, M. W. Stasell
The need to deliver new vehicle designs to the marketplace in shorter time periods is mandating a change to the “do it right the first time” design philosophy. Multiple stages of prototyping must be reduced to one or two stages in order to reduce cycle development time to meet market demands. This paper discusses an effort to reduce the development time for an aero package through the integration of finite element analysis (FEA) and laboratory testing. FEA provides design guidelines prior to prototype testing and a mathematical prototype on which changes can be quickly evaluated during testing. Laboratory testing, using an electrohydraulic system with Remote Parameter Control (RPC), provides accurate accelerated durability testing of the design.
1988-10-01
Technical Paper
881860
Robert W. Morrison, Peter W. Strause, Walter Pienta, John Krebs
Simultaneous engineering techniques have been applied to a SMC truck hood to reduce the lead-time for production introduction from 22 months to 12 months. Several other technologies were also applied to insure a successful product introduction in this reduced timeframe: computer definition of the hood surface for accuracy, RTM prototype tooling for early design tryout and durability testing, Finite Element Analysis to further confirm durability of the hood structure, and brittle lacquer combined with strain gaging to provide life data using a hydraulic road simulator for load inputs.
1988-10-01
Technical Paper
881859
Kiyoshi Minami, Tohru Yasuma, Shigeru Okabayashi, Masao Sakata, Itsuro Muramoto, Tadao Kohzu
The serious highway accidents related to heavy-duty trucks were caused mainly by absent-minded conditions of drivers, according to an investigation of highway accidents in Japan. Thus, a collision avoidance warning system has been developed. A laser radar sensor detects the distance to a reflector of the target vehicle. Together with information of the own vehicle speed detected by a magnetic pick-up, a microcomputer assesses the risk of a rear-end collision and provides warning when a dangerous condition has developed. Warning suppresion is considered in unnecessary situations, such as driving in curves, driving at constant speed and distance, and driving at low speed. The system was installed on a heavy-duty truck, and a system evaluation test was carried out on proving grounds and highways. As the result, false alarms created by reflectable objects located adjacent to the road and unnecessary warning could be sufficiently suppressed, and the system was found to be useful.