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Technical Paper

Electromagnetic Compatibility in the Off-Highway Vehicle

The key words in the marketplace for off-highway vehicles are durability, performance, and efficiency. A manufacturer of these vehicles recognizes that one way to successfully address these needs is by a well thought through electronics design. With the computer sophistication now being incorporated into off-highway vehicles, engineers must work closely to assure electromagnetic compatibility (EMC) of the entire system. A properly established EMC program extending from concept to final design will support each of a product's specified operations and still function as an integrated whole. This paper describes the process for designing the EMC for an off-highway vehicle.
Technical Paper

Preparation and Testing of an Electric Competition Vehicle

A Dodge Omni electric car was prepared for competition in an electric “stock car” 2-hour endurance event: the inaugural Solar and Electric 500 Race, April 7, 1991. This entry utilized a series-wound, direct-current 21-hp electric motor controlled by an SCR frequency and pulse width modulator. Two types of lead-acid batteries were evaluated and the final configuration was a set of 16 (6-volt each) deep-cycle units. Preparation involved weight and friction reduction; suspension modification; load, charge and temperature instrumentaltion; and electrical interlock and collision safety systems. Vehicle testing totalled 15 hours of operation. Ranges observed in testing with the final configuration were from 30 to 52 miles for loads of 175 to 90 amperes. These were nearly constant, continuous discharge cycles. The track qualifying speed (64mph) was near the 68 mph record set by the DEMI Honda at the event on the one-mile track.
Technical Paper

An Intake Charge Cooling System for Application to Diesel, Gasoline and Natural Gas Engines

Low intake manifold temperature, well below ambient, has many applications in internal combustion engines. In diesel engines, it can reduce NOx to a level of 2.0 g/hp-hr or below, going beyond the 1994 heavy duty diesel engine emissions standards. In gasoline engines, it can allow high compression ratio, turbocharged operation without end gas knock. This will permit ready conversion of some heavy duty diesel engines to gasoline operation at increased power density and lower emissions. In natural gas engines, it will allow base diesel engine to be converted to stoichiometric natural gas operation without increasing thermal loads. A three way catalyst can then be used to reduce emissions.
Technical Paper

Electronic Data Acquisition and Analysis for the NHTSA ABS Fleet Evaluation

Antilock brake systems for air braked vehicles have been growing in popularity in Great Britain and Europe and appear to be candidates for extensive use in the United States as well. Previous mandated use in the United States during the 1970's was not successful, in part because of reliability problems, and the National Highway Traffic Safety Administration (NHTSA) has decided that a thorough evaluation of air brake antilock systems is necessary prior to any decision about the appropriateness of future mandatory use in the United States. This paper describes the electronic data collection equipment and processing techniques which are being used in the NHTSA 200 truck evaluation project. Detailed maintenance histories for each truck are being recorded manually as a separate segment of the project. An average of 6 to 7 megabytes of data per week is being collected in the various cities in which fleets are operating test vehicles.
Technical Paper

Probabilistic Structural Analysis Methods

The purpose in doing probabilistic structural analysis is to provide the designer with a more realistic ability to assess the importance of uncertainty in the structural response. This paper provides an overview of the methodology and discusses validation of modular structural analysis packages capable of predicting the probabilistic response distribution for key structural variables such as stress, displacement, natural frequencies, buckling loads, transient responses, etc. The structural analysis solution is in terms of the cumulative distribution function (CDF). Probabilistic structural analysis methods (PSAM) can be used to estimate structural safety and reliability, while providing the engineer with information on the confidence that should be given to the predicted behavior.
Technical Paper

Options for the Introduction of Methanol as a Transportation Fuel

It is generally recognized chat methanol is the best candidate for long-term replacement of petroleum-based fuels at soma time in the future. The transition from an established fuel to a new fuel, and vehicles that can use the new fuel, is difficult, however. This paper discusses two independent investigations of possible transition uses of methanol, which, when combined, may provide an option for introduction of methanol that takes advantage of the existing industrial base, and provides economic incentives to the consumer. The concept combines the intermediate blends of methanol and gasoline (50%-70% methanol) with the Flexible Fuel Vehicle. In addition to a possible maximum cost effectiveness, these fuels ease vehicle range restrictions due to refueling logistics, and mitigate cold starting problems, while at the same time providing most of the performance of the higher concentration blends.
Technical Paper

Automated Planning and Resource Management in an Autonomous Underwater Vehicle

The Autonomous Underwater Vehicle (AUV) is a fully automated robot submarine that is capable of maintaining a set of electronic sensors under the polar icecap. This function is primarily an issue of automated planning. The AUV is driven by three independent, and often conflicting, goals. These are mission, survival, and covertness. The plan that must be generated is essentially a route to achieve a mission that is acceptable to all three goals. The conflicting goals are implemented as independent expert systems that place constraints on the route taken. A higher level arbiter is used to help resolve conflicts in the situations where restraints posed by the independent goals preclude any solution being found.
Technical Paper

Low Heat Rejection Engines

The paper gives a general overview of the state-of-the-art in low heat rejection (LHR) engines. It also gives experimental results obtained at SwRI with a single-cylinder research engine using an electrically heated cylinder liner to simulate LHR operation and examine the effects of increased liner temperature. It was concluded that the improvement in fuel economy from LHR operation is negligible in naturally-aspirated (NA) engines, about 7 percent in turbocharged (TC) engines and about 15 percent in turbocompound (TCO) engines. LHR operation reduces power in NA engines only. It increases NOx emissions by around 15 percent, but reduces HC and CO emissions. LHR operation offers benefits in the reduction of noise and smoke, and in operation on low cetane fuels. Much more research is needed to overcome the practical problems before LHR engines can be put into production.
Technical Paper

A Second Generation Expert System for Diagnosis and Repair of Mechanical and Electrical Devices

Existing expert systems have a high percentage agreement with human experts in a particular field in many situations. However, in many ways their overall behavior is not like that of a human expert. These areas include the inability to give flexible, functional explanations of their reasoning processes and the failure to degrade gracefully when dealing with problems at the periphery of their knowledge. These two important shortcomings can be improved when the right knowledge is available to the system. This paper presents an expert system design, called the Integrated Diagnostic Model (IDM), that integrates two sources of knowledge: a shallow, empirically-oriented, experiential knowledge base and a deep, functionally-oriented, physical knowledge base. To demonstrate the IDM's usefulness in the problem area of diagnosis and repair of electrical and mechanical devices, two implementations and our experience with them is described.
Technical Paper

Microcomputer Control System Design for a Tracked Amphibious Vehicle

A 14-ton tracked amphibious vehicle has been equipped with a hydrostatic drivetrain that consists of land drive and seaborne transmissions. The transmissions and the vehicle's engine are under microcomputer control. In addition, the microcomputer reads operator inputs and does operational checks of the vehicle's various subsystems. If arty of the subsystems is found to be degraded in their performance the microcomputer informs the operator. This paper presents an overview of the drivetrain systems and the implementation of the control and diagnostic systems.
Technical Paper

Application of a Commercially Available Process Control Computer to Engine Testing

This paper describes a distributed digital process control computer designed for large industrial processing plants that has been applied successfully to laboratory engine testing. Over the past two years several complete systems have been installed and adapted to control engines from 75 kW to over 1800 kW with various dynamometer/generator absorption devices. Control problems encountered, and solutions we have found, are discussed along with the wide range of capabilities this type of system can provide. A short comparison is made between distributed digital control systems and mini-computers, listing advantages and disadvantages of both.
Technical Paper

Evaluation of Emission Control Technology Approaches for Heavy-Duty Gasoline Engines

This paper summarizes a laboratory effort toward reducing nine-mode cycle composite emissions and fuel consumption in a heavy-duty gasoline engine, while retaining current durability performance. Evaluations involved standard carburetors, a Dresserator inductor, a Bendix electronic fuel injection system, exhaust manifold thermal reactors, and exhaust gas recirculation, along with other components and engine operating parameters. A system consisting of electronic fuel injection, thermal reactors with air injection and exhaust gas recirculation, was assembled which met specified project goals. An oxidation catalyst was included as an add-on during the service accumulation demonstration. In addition, the driveability of this engine configuration was demonstrated.
Technical Paper

Automated Acquisition and Reduction of Engine Lubricant Test Data

An automated data handling system to assist in the operation of a diesel engine lubricant test laboratory, involving two mini-computers, is described in terms of why it was needed, the design goals sought, and the operating experience which resulted from its use. The concept of two digital systems, one for on-line data logging and another as a ready back-up, as well as a data processor, is discussed. Direct and peripheral benefits which have resulted from the application of the system, such as semi-automated report processing, operational aids, and various engineering applications, are reported.
Technical Paper

Diagnostics of Diesel Engines Using Exhaust Smoke and Temperature

An experimental sensor array that measures dynamic exhaust temperature and dynamic smoke for the purpose of diagnosing diesel engine fuel injection equipment was designed, built, and tested. The sensor array is portable and easily installed on truck tailpipes, and was tested using two 6V-53 Detroit Diesel engines. The dynamic temperature sensor is a very high response instrument capable of measuring changes in gas temperature in excess of 104°F/second. The dynamic smokemeter is an optical device designed to measure very low levels of light opacity in the smoke plume, with a response compatible with the engine firing frequency. Dynamic exhaust temperature data had more diagnostic significance than dynamic smoke in the detection of maximum power degrading fuel injection faults.
Technical Paper

Emissions Control of Gasoline Engines for Heavy-Duty Vehicles

This paper summarizes an investigation of reductions in exhaust emission levels attainable using various techniques appropriate to gasoline engines used in vehicles over 14,000 lbs GVW. Of the eight gasoline engines investigated, two were evaluated parametrically resulting in an oxidation and reduction catalyst “best combination” configuration. Four of the engines were evaluated in an EGR plus oxidation catalyst configuration, and two involved only baseline tests. Test procedures used in evaluating the six “best combination” configurations include: three engine emission test procedures using an engine dynamometer, a determination of vehicle driveability, and two vehicle emission test procedures using a chassis dynamometer. Dramatic reductions in emissions were attained with the catalyst “best combination” configurations. Engine durability, however, was not investigated.
Technical Paper

Spectrometric Analysis of Used Oils

This paper discusses the techniques and diagnostic significance of atomic absorption, atomic emission, and infrared spectrometric analysis of crankcase lubricants, with the use of supplementary data where pertinent. The parameters affecting used oil analytical data are discussed in terms of examples from Army general purpose vehicle test engines. Wear metals in used gear oils are also discussed and examples are given. Analytical methods and their applications are fully described, and the equipment and procedures for infrared spectroscopy and gas chromatography techniques are outlined.
Technical Paper

Noise Reduction Techniques as They Apply to Engine-Generator Design and Treatment

Small engines may require soundproofing to eliminate one or more of the following effects: hearing loss, speech interference, community annoyance, detectability, and psychological disorientation. Detectability criteria are frequently associated with military applications and may require the use of a soundproof enclosure in addition to other engine treatments. Acoustical noise sources are conveniently classed as either aerodynamic or mechanical. Aerodynamic sources are predominant on small engines. Treatment of exhaust noise by individual components, e.g., muffler, is inadequate; a system approach, through the use of an electro-acoustic analog computer, has proved to be a much more satisfactory procedure.
Technical Paper

A Temperature Telemetry Technique for Reciprocating Engines

A unique system has been devised to measure and telemeter critical temperatures of reciprocating engine components. A prototype has been used to measure the piston pin bearing temperature in a full-scale EMD 2-567D diesel engine.