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Technical Paper

Using Modern Technology to Improve Truck Seating

Many advancements have been made through the use of technology that give seat manufacturers the capability to provide greatly improved truck seats. Until recently the design and development of new seating was accomplished primarily through static surveys. Modern technologies available today will reduce cost, development time, and the overall effort associated with utilizing real people to develop a seating project. In many instances when these seats were placed into vehicles with actual truck drivers riding in them for many hours a day, the drivers inputs resulted in multiple revisions to the original seat to satisfy their comfort issues. With modern technologies such as computer generated seat modeling, pressure mapping, and our state of the art test equipment such as a six–axis ride simulator, it has become part of any new seat development program to acquire field ride data in specific trucks and duplicate these inputs in the test laboratory.
Technical Paper

Dynamometer Simulation of Truck and Bus Road Horsepower for Transient Emissions Evaluations

Appropriate chassis dynamometer simulation of road power for truck tractor-trailers and buses were required for emissions evaluations. To establish such simulations, the power required to operate vehicles over a roadway (speed-power relationship) was determined for two truck tractor-trailers and one city bus. Results of these determinations, along with data reported in the literature, were used to determine the power to be absorbed by a chassis dynamometer to simulate On-road driving of trucks and buses. The chassis dynamometer is being used in the subsequent phases of this study involving emissions evaluations of heavy duty vehicles. THE PURPOSE OF THIS PAPER is to describe the findings associated with road power determination and simulation for heavy-duty trucks and buses. Included is a general discussion of road power, along with the results of evaluations on the road and on the chassis dynamometer.
Technical Paper

Diagnostic Aids Required to Support Service Technicians in Construction Machinery Dealerships

The manufacturers goal of maximizing product uptime and maintaining acceptable levels of repair costs is significantly influenced by diagnostics. Diagnostic aids such as test equipment, technical manuals, diagnostic procedures, combined with dealership service department operations, technical training and design of the manufacturers product line directly affect a service technician’s ability and capability to properly support a product. In an “ideal” diagnostic situation, results of reduced diagnostic error and repair costs, with improved product uptime and marketability are more readily achieved. The combined influence of all the factors affecting diagnostics are best considered in total, versus consideration of each factor separately.
Technical Paper

Speed and Power Regressions for Quality Control of Heavy Duty Vehicle Chassis Dynamometer Research

When performing a transient test on a heavy-duty engine as outlined in the Code of Federal Regulations (CFR), defined regression values of engine speed, torque and power must meet specific tolerances for the test to be considered valid. Regression of actual engine feedback data against target points from a schedule defined from an engine map is performed using the method of least squares to determine the slope, intercept, coefficient of regression and standard error of the estimate. To minimize the biasing effects of time lag between actual and schedule data, shifting of the data in the time domain prior to analysis and certain point deletions are permitted. There are presently no regression criteria available for heavy duty chassis testing. This leaves facilities performing these chassis tests with no suitable guidelines to validate individual tests. This study applies the regression analysis used in engine testing to chassis testing and examines the difficulties encountered.
Technical Paper

Software Life-Cycle Costs and Solutions

Electronic control system manufactures within the off-highway industry are aggressively upgrading their embedded software development processes to include simulation, rapid prototyping, and Hardware-in-loop testing (HIL). However, software life cycle concerns are not always considered during process revolutions such as these, even though most project managers agree that the majority of software costs accrue during maintenance. This paper proposes the use of automated implementation and unit test tools to generate production code and unit test vectors from a graphical representation of the ECU model used during simulation and prototyping. These automated tools not only improve development time but, more importantly, save on maintenance and reuse costs. Another proposal is made herein regarding the use of a new rapid prototyping environment for more accurately accounting for production microcontroller constraints during control algorithm design.
Technical Paper

Computer Controlled Automatic Test Equipment Concepts

In designing and developing a computer based automatic test equipment (ATE) system, the interaction between the major elements of the system is as important as the choice of elements themselves. This paper first looks at the five major elements of an engine ATE system and then discusses the interactions of these major elements together as a system. Computer simulation, the first element, is used to define the process and its limits. It is also used later to test and optimize plant level designs. A second major element of an engine ATE system is the definition of the individual processes and the decision on the control technique to employ. A third element is the choice of software language - should the system use a specialized test language that is optimized for the process, or should a more general purpose, widely understood language be used. A fourth parameter that becomes more important as the system grows is communication technique.
Technical Paper

Test Tools for CAN Networks

Networking is a need for interlinking todays and future electronic modules into systems. Networked systems offer reduced wiring harness, more open system expandability and an additional degree of freedom for system optimization. On the other hand networked systems represent highly complex problems for the system designers and therefore require correspondingly powerful tools. Subsequently the characteristics of networking are described based on the example of the CAN-network-protocol. A set of requirements for needed tool support is derived from the inherent networked system characteristics. A set of CAN network development tools is described - Simulator, Emulator, Analyzer, handy NetTest, PcNet-interface - supporting the various needs in the different design phases. Finally some future activities are described depicting tools enhancement and integration. In addition research activities are mentioned focusing on definition and evaluation of higher protocol layers.
Technical Paper

Meeting ISO 8178 Requirements for the Measurement of Diesel Particulates with Partial-Flow Dilution Systems

The ISO 8178 Draft for Particulate Measurement of Off-Highway Diesel engines specifies partial-flow dilution systems as the preferred measurement equipment. Two critical points of such systems are presented in this paper: First, the correct implementation and/or determination of exhaust sampling and dilution ratio within the accuracy limits of ISO 8178. Second, the influence of size, length and temperature conditioning of the transfer tube and tunnel on particulate formation, deposition and re-entrainment. As a result of our investigations, recommendations for the proper layout of a partial-flow dilution system are given. Such a system will yield particulate emission values closely following the values obtained with a full-flow CVS system, where engine size permits the comparison. Where the engine size precludes the full-flow dilution, a particulate test equipment with proven correlation to a CVS system should be used
Technical Paper

Metrology: A Definition of Quality

Since defining quality so it will be accepted from company to company is a difficult task. This paper will discuss definitions of quality and how metrology can assist a company in defining its' quality. The title; Metrology:A Definition of Quality implies an explanation of how metrologists thinking has become important to companies committed to quality. This paper discusses the advantages quality programs derive from having metrology heavily involved in their processes and procedures. This paper also talks about the changing role of metrologists from strictly calibrating of the test equipment to applying process metrology in order to ensure the overall quality of the products.
Technical Paper

The Interaction of Fuel Spray and Air Swirl in a Diesel Combustion Chamber with Nitrogen Gas Circulation

A single cylinder engine was modified into a photographic test equipment. A new method-filling and cycling nitrogen gas to the cylinder-was used to keep the fuel in combustion chamber out of firing. Tests were carried out at three fuel injection pressure and three gas swirl rates. The chamber swirl rate was measured by hot-wire anemometer, the fuel spray pictures were taken by a high speed camera. By reference to the experimental results, the spray bevaviers in swiling flow were discussed both in the main injection and the end injection periods.
Technical Paper

The Use of a Chassis Dynamometer for Urban Transit Bys Preventive Maintenance Inspection

The use of a chassis dynamometer for inspection maintenance and drive train fault diagnosis has been developed for urban transit buses. Transit bus maintenance management has long sought a means to optimize bus preventive maintenance intervals. Historically, transit bus preventive maintenance has been scheduled with either time or mileage as the controlling parameter. This paper provides a basis for implementing vehicle dynamic testing that can substantially reduce the costs and manpower associated with preventive maintenance inspections and repairs. By subjecting the whole bus to the appropriate repeatable test conditions, certain measurements can be made to ascertain system parameters which can then be compared to established standards to indicate deteriorating conditions and diagnose defects. Dynamic inspection on a chassis dynamometer reduces to practice the maintenance principle, “if it works, don't fix it.”
Technical Paper

The Latest Developments in Heavy Duty Vehicle Aftertreatment Testing for Real World Emissions and Fuel Economy

Current Heavy Duty testing is performed almost exclusively on engine dynamometers. The limitations of this method to obtain detailed emission data for heavy duty vehicles operating in the field are widely known. The wide variety of vehicles into which an engine type may be fitted and the disparate operating conditions that the vehicle is then subject to, mean that the real environmental impact of heavy duty vehicles can never be established. A Variable Temperature Emissions Chamber (VTEC) has been developed and used for chassis dynamometer testing of numerous road vehicles right up to Double Decker Buses. This facility enables accurate emissions data to be measured for specific vehicles in their real operating environments. The facility is equipped to simulate ambient temperatures from -30°C to + 50°C and with a high volume, speed tracking air flow. Driving cycles have been developed for buses and trucks, both from detailed on-road data logging and from simulated operations.
Technical Paper

Performance Testing Equipment for 11 - 26 in Diameter Heavy-Duty Torque Converters

This paper shows the necessity of extensive machinery and instruments to test torque converters. Review of the principle options and reasons for choice of particular machines and instruments for testing torque converters through the full range of possible performance, that is, through coast and counterrotation as well as normal operation.
Technical Paper

Prediction of Dynamometer Power Absorption to Simulate Light Duty Truck Road Load

When vehicle exhaust emission tests or vehicle fuel consumption measurements are performed on a chassis dynamometer, the dynamometer is usually adjusted to simulate the road experience of the vehicle. In this study, road load versus speed data were obtained from 15 light duty trucks. The road load of each truck was determined for different pay loads, resulting in a total of approximately 50 road load measurements. Dynamometer power absorption settings to simulate the measured road loads are computed. These dynamometer settings are regressed against vehicle frontal area and vehicle inertia weight. It is concluded that the dynamometer load settings are most accurately predicted on the basis of the vehicle frontal area.
Technical Paper

Analysis of Torsional Vibration for a Multi-Branch Drive-Train in a Chassis Dynamometer

Due to the rapid development in advanced complex machinery, the analysis of torsional vibrations for multi-junction, multi-branch systems is becoming a subject of increasing interest. Torsional vibration may occur within an operation range in a rotating system and cause a serious failure in the machine. This is the case when an excitating frequency gets close to the natural frequency of the system. In this paper, an efficient and accurate method has been developed to calculate torsional natural frequencies of complex rotating systems. The method is used in designing a drive-train of a chassis dynamometer simulating a multi-junction, multi-branch rotating system. Natural frequencies and mode shapes of the drive-train have been determined and used for further development in the components of the system.
Technical Paper

Research on the Behaviour of Heavy Mobile Machinery in Simulated Subzero Conditions

The operational behaviour of hydraulic and mechanical systems in subzero temperatures is of considerable interest to manufacturers and operators of mobile and earthmoving machines which work in extremely cold climatic conditions. The majority of such machines are designed for operation in moderate climatic conditions and will have to be specially adapted for working in very low temperatures. The adaptation of such machines to operation in subzero temperatures and verification of their operational limits may be very expensive as it usually requires field testing. To carry out such tests the machines and test equipment must be transported to a low temperature zone. The conduct of tests is weather dependent and only limited modifications to machines are possible under field conditions.
Technical Paper

Electromagnetic Compatibility in the Off-Highway Vehicle Part III: Electromagnetic Emissions (EME)

Electromagnetic emissions (EME) from vehicles and their effect on broadcast radio and television were studied as early as 1944. Their original effect was significantly reduced by the early 1960s. Today, ignition noise (broadband) and vehicular micro-processor-controlled system noise (narrowband) are interfering with Land Mobile (two-way) communication services and other devices such as computers. Two SAE test methods, J551 and J1816, are used to measure this EME. Under development are methods to measure conducted EME on vehicle signal wiring and power input leads. This paper discusses EME measurement methods, provides insight into the sources of EME problems, and gives information on the test instrumentation used to make these measurements. This paper is the third in a series of papers on electromagnetic compatibility (EMC) in the off-highway vehicle. The first paper was an overview of a complete EMC program with discussion of several important segments.

Engine Testing with Low-Temperature Charge Air-cooler Systems in a Dynamometer Test Cell

The methods presented in this SAE Recommended Practice apply to the controlled testing of low-temperature charge, air-cooled, heavy-duty diesel engines. This document encompasses the following main sections: a Definitions of pertinent parameters b Vehicle testing to determine typical values for these parameters c Description of the setup and operation of the test cell system d Validation testing of the test cell system While not covered in this document, computer modeling of the vehicle engine cooler system is recognized as a valid tool to determine cooler system performance and could be utilized to supplement the testing described. However, adequate in-vehicle testing should be performed to validate the model before it is used for the purposes outlined. The procedure makes references to test cycles that are prescribed by the United States Environmental Protection Agency (US EPA) and are contained in the Code of Federal Regulations.