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Technical Paper

Why Multicylinder Motorcycle Engines?

1969-02-01
690748
Combustion engines with up to 48 cyl have been built. It is shown that this is neither accident nor fanciness when high specific power output is involved. As is demonstrated on hand of equations, the subdivision of a certain displacement into larger numbers of smaller cylinders brings about a substantial increase in power. At this time, for example, more than twice that of single cylinder engines. Values of highly developed motorcycle competition engines are compared with these theoretical results and an amazingly high degree of agreement exists. These laws are not limited to motorcycle engines, but may be used for other applications also.
Technical Paper

Why Not 125 BMEP in an L-Head Truck Engine?

1939-01-01
390130
HIGH output per cubic inch of piston displacement is desirable not alone for the purpose of being able to transport more payload faster, but more particularly for the invariably associated byproduct of lower specific fuel consumption, and especially at road-load requirements. The only way of accomplishing this purpose is through the use of higher compression ratios, and the limiting factors for this objective are fuel distribution and the operating temperatures of the component parts. A manifold is proposed which not only definitely improves distribution at both full and road loads, but has the inherent additional advantage of reducing the formation of condensate, thus still further facilitating a reduction in road-load specific fuel consumption. Hydraulic valve lifters, obviation of mechanical and thermal distortion, and controlled water flow are the essentials in improved cooling.
Technical Paper

Why Not Convert to Ductile Iron?

2002-03-19
2002-01-1451
Cast iron is generally thought of as a weak, dirty, cheap, brittle material that does not have a place in applications requiring high strength and defined engineering properties. While gray cast iron is relatively brittle by comparison with steel, ductile iron is not. In fact, ductile iron has strengths and toughness very similar to steel and the machinability advantages make an attractive opportunity for significant cost reductions. Gray and ductile iron bar stock is commercially available and can be used as a direct replacement in applications that are currently being made from carbon steel bar. Ductile iron bar stock conversions are very prevalent in many fluid power applications including glands and rod guides, cylinders, hydrostatic transmission barrels and in high-pressure manifolds. Automotive gears are being converted to ductile iron for its damping capacity and cost reductions.
Technical Paper

Why Not Evolve Into the Solar System with a Sensible Space Utilization Architecture?

1990-09-01
901862
Numerous space projects are underway worldwide which, in the long run, intend to further expand humankind's reach into space and to accelerate the discovery and utilization of resources there. Specific initiatives involving extensive human space activity have been proposed by the US, USSR, European Space Agency and Japan, particularly in Earth orbit, on the Moon and at Mars. As an integrated whole, these proposals suggest an increasing demand for launch systems, upper stages, maneuvering and orbit transfer vehicles of all kinds, and significant increases in total habitable volume in various orbits and extraterrestrial surfaces. There is one critical flaw in all of this, however, that is choking progress every step of the way: the space infrastructure has no architecture; it has no conceptual integrity.
Technical Paper

Why Not Triples?

1974-02-01
740619
The size and weight of commercial motor vehicles have been effectively frozen since the adoption of the Federal Aid Highway Act of 1956. The removal of political barriers for the liberalization of these restrictions will help stem the tide of inflation, while at the same time making potential fuel savings of as much as 21% for intercity freight trucks a reality. With transportation a recurrent cost in every phase of production, distribution, and service, fuel becoming more expensive, and the security of supply more tenuous, the significant increase in transportation efficiency provided by the triple trailer combination must not be withheld from the nation's economy. Millions of operational miles have clearly demonstrated that our nation's highways have been built to the point where they can safely handle this equipment, with triples having established the best safety record of any vehicle ever used on our highways.
Technical Paper

Why Not a New Engine ?

1980-11-01
801428
Leading contenders in the search for a superior alternative powerplant for light-duty automotive use include the steam and Stirling engines, the gas turbine, and the diesel. In this paper the status of each of those alternative engines is reviewed and i its prognosis considered. The steam engine is unsuitable because of poor fuel economy. Obstacles blocking acceptance of the Stirling and gas turbine engines are sufficient so that even if they are surmountable, significant-use in light-duty vehicles is unlikely before the 1990s. The light-duty diesel is here today but faces some difficult regulatory hurdles in the near future.
Technical Paper

Why Our Landfill Equipment Needs are Different

1972-02-01
720383
Waste disposal is no longer a simple matter of finding landfill areas and dumping in the refuse cast off by the public and industry. As this paper emphasizes, landfill must be considered as salvageable real estate useful for later development. This requires specialized techniques and specialized machinery, all of which have identifiable needs that are unlike those of the usual earthmoving operations. How much these needs differ and how they can be satisfied by design changes to produce efficient machines capable of handling continuous, all-weather landfill programs are highlighted. The urgency of findings ways to handle an ever increasing burden of trash and waste is a compelling reason for solving the problems of this industry.
Technical Paper

Why P/M Provides the Advantage

1998-02-23
980310
In conventional powder metallurgy (P/M), structural stainless steel parts are produced by pressing alloy powder of the appropriate composition in a die to produce a compact. The compact is then sintered at an elevated temperature in a controlled atmosphere, bonding the particles together by diffusion and densifying the part. In this paper the P/M process is reviewed and its capabilities are discussed. Following this, the more common stainless steel compositions are detailed and the advantages of the P/M process are summarized.
Technical Paper

Why People Die in Motor Vehicle Crashes: Linking Detailed Causes of Death with FARS Data

1998-02-23
980216
NHTSA's Fatal Crash Reporting System (FARS) collects information on all US fatal public roadway motor vehicle crashes.1 However, FARS contains only the information “K”(killed) as injury information for the individuals sustaining fatal injuries. This paper discusses how a 100 fold improvement in injury detail can be obtained with ICD-9 mortality information by linking FARS with the Vital Statistics Multiple Cause of Death (MCOD) database.2 This link, developed by NHTSA, is accomplished on an individual by individual basis. The FARS database contains about 40,000 individuals killed per year, and nearly 25 years of data available. A multi-year linked FARS-MCOD database can contain detailed cause of death for more than 1,000,000 motor vehicle fatalities. The linked FARS-MCOD allows the reasons why people die in MVC to be studied down to specific vehicle make/model combinations.
Technical Paper

Why Private Carriage - Why Not?

1974-02-01
740776
The decision to adopt private carriage for regular movement of freight by a manufacturer was a two-step process. The first step was the conclusion after study that air transportation had far more cost benefits than surface transport. Once this decision was reached, the various modes of air transportation--scheduled airlines, nonscheduled operators, and private carriage-were surveyed, and it was found that private carriage was the least costly mode. The experiences encountered and lessons learned in six years of private carriage are presented.
Technical Paper

Why SAE J1739?

1995-02-01
950569
SAE J1739 is the revised coordinated Big Three (Chrysler, Ford and General Motors) Failure Mode and Effects Analysis Reference Manual for both design and process analyses. It replaces the Big Three FMEA Reference Manual which was released through the Automotive Industry Action Group (AIAG) in 1993. This paper tells why SAE J1739 was developed by Chrysler, Ford and General Motors, describes the historical events leading up to SAE J1739, and describes the key features and the advancements in automotive FMEA application reflected by SAE J1739.
Technical Paper

Why Separate Simulation of Input Influences for Accelerated Reliability and Durability Testing is Not Effective?

2017-03-28
2017-01-0276
This paper considers the situation in the laboratory testing: different stress types and accelerated testing, including accelerated reliability/durability testing, accelerated life testing, reliability testing, proving grounds, vibration, temperature, voltage, humidity, and others. In comparison with field situation, most of these testing simulate only one or part of the field input influences. One uses often not accurately the theory of physics-of-degradation process or failures for comparison of the field results with laboratory results. This situation will be considered with practical examples. It will be demonstrated that often used laboratory testing does not offer the possibility for successful prediction of product performance during service life As a result, there are many complaints, recalls, and less profit than was predicted during design and manufacturing. It will be shown how one can improve this situation..
Journal Article

Why Should Auto-Generated C be Treated any Differently from Hand-Coded C?

2008-04-14
2008-01-0661
Many embedded software developers producing C code for automotive applications will be familiar with the MISRA C guidelines. These provide practical guidance in avoiding some of the common pitfalls associated with the C language. They were originally meant for automotive developers, but are now increasingly used in other critical sectors such as aerospace and medical devices. The commonly-held view, expressed in the MISRA C guidelines, is that all C code, whether hand-written or automatically generated, should be subjected to exactly the same verification and validation activities. However, as modeling language and automatic code generation techniques have evolved over the 10 years since the first edition of MISRA C, this advice may no longer be so relevant. This paper looks at some of the issues related to verification and validation of automatically-generated C code and identifies the situations in which the authors believe that a different approach is warranted.
Technical Paper

Why Simulation? An Interesting Case Study

2016-04-05
2016-01-1484
This paper presents an example application for vehicle dynamics simulation software. This example investigates the validity of the vehicle motion presented in the famous car chase scene from the 1968 movie Bullitt. In this car chase, a 1968 Ford Mustang, driven by Det. Frank Bullitt of the San Francisco Police Department, is chasing a criminal driving a 1968 Dodge Charger through the streets of the Russian Hill district of San Francisco. The purpose of the simulation was to reconstruct the chase scene to determine the level of realism in the movie, in terms of conformance to Newton’s Laws of motion. To produce the simulation, several city blocks of the pertinent area of the city were surveyed and exemplar vehicles were measured and inspected. Three-dimensional computer models of the scene and vehicles were built. The movie footage was analyzed to determine vehicle speeds and driver inputs. The event was then simulated using three-dimensional vehicle dynamics simulation software.
Technical Paper

Why Simulators are More Difficult to Fly Than Aircraft

1991-09-01
912098
Simulators are typically more difficult to fly than the aircraft they represent. The factors involved include limited field of view, degraded visual acuity, scene distortion, absence of depth perception, attenuation or absence of motion cues, and response delays that are often inconsistent among visual, motion, and instruments. It is suggested that for most training tasks the added difficulty because of these factors is not a drawback, and should not be alleviated at the expense of dynamic fidelity.
Technical Paper

Why Some Passenger Car Motor Oils Are No Longer Suitable for Motorcycles: Gear Pitting Issues

2005-10-12
2005-32-0088
The new American Petroleum Institute (API) categories for passenger car motor oils have focused on improving fuel economy and reducing emissions. This has resulted in more fuel efficient oils being developed by lowering the viscometrics and by adding friction modifiers. The emissions reductions have resulted from lowering the percent phosphorus (%P) in the engine oils because phosphorus has been found to poison the catalyst in the catalytic converter. When friction modifiers were introduced, researchers from four Japanese motorcycle manufacturers published the results of their studies (SAE 961217) which indicated that low friction oil can cause too much slippage in starter motor clutches, one-way limited slip clutches, and wet multi-plate clutches. In that same study they reported that engine manufacturers use 10W-30 grade oil to develop new engine technology, and gear pitting was observed with oils of viscosity grades lower than 10W-30 in all four manufacturers' motorcycle engines.
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