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The conceptual design for a large scale, alternative motor fuels demonstration using delivery vans in the Los Angeles area is described. Vehicles built by Chrysler, Ford, and General Motors will be demonstrated on compressed natural gas, methanol (M-85), ethanol blend, reformulated gasoline, and liquefied petroleum gas. Control vehicles will run on unleaded gasoline. About 20 vehicles will run on each fuel. A smaller number of electric vehicles from other sources will also be demonstrated. Data will be collected over a 24-month period on speciated emissions, safety, performance, reliability, maintenance, and durability. An economic assessment of the use of each of the fuels will be performed from a fleet operator's perspective. Federal Express Corporation will serve as the host fleet.

Natural Gas engines are viewed as an alternative to diesel power in the quest to reduce heavy duty vehicle emissions in polluted urban areas. In particular, it is acknowledged that natural gas has the potential to reduce the inventory of particulate matter, and this has encouraged the use of natural gas engines in transit bus applications. Extensive data on natural gas and diesel bus emissions have been gathered using two Transportable Heavy Duty Vehicle Emissions Testing Laboratories, that employ chassis dynamometers to simulate bus inertia and road load. Most of the natural gas buses tested prior to 1997 were powered by Cummins L-10 engines, which were lean-burn and employed a mechanical mixer for fuel introduction. The Central Business District (CBD) cycle was used as the test schedule.

A validated three-dimensional mathematical model was used to examine the extent of flammable plumes resulting from both large and small CNG leak scenarios inside a typical transit maintenance and storage facility ventilated at a rate of five air changes per hour. The leak rates used were based on an engineering and experimental analysis of actual CNG bus fuel system components. The results showed that both large and small CNG leaks produced flammable plumes, such plumes extended from a half a bus length to several bus lengths away from the leak source, and the plume from a large leak formed a layer along the ceiling before being dispersed by building ventilation.

A study to determine whether performance-based brake testing technologies can improve the safety of our highways and roadways through more effective or efficient inspections of brakes of on-the-road commercial vehicles is being sponsored by FHWA/DOT-OMC. A key objective of the study is to determine how the results from performance-based “inspections” compare with results obtained through traditional visual methods, such as those recommended by the Commercial Vehicle Safety Alliance (CVSA). Data from joint inspections (i.e., CVSA and performance-based inspections on the same vehicle), obtained over approximately a one year period, have been analyzed. Description of three of the performance-based technologies and preliminary results from approximately 1,400 joint inspections are covered in this paper.

There is recent interest in examining whether performance-based brake tests are advantageous compared to presently used visual inspections for safety checks of on-the-road commercial vehicles. In this first of a series of two papers, the basic features of visual inspections and performance-based brake tests are presented and discussed. It is shown that the visual inspection method is inherently “predictive” in nature and therefore conservative. A performance-based brake test is objective but not predictive. The performance based test may reveal safety-related defects only for the specific vehicle load configuration and operating condition. The presentation is concluded with a discussion of what may be required for future enforceable use of performance-based brake testing devices for “on the road” inspections of commercial vehicles. In the short term, use of performance based testing will depend on correlation of test results with presently enforceable visual methods or standards.

An important part of ITS (Intelligent Transportation Systems, formerly IVHS) is the development of collision avoidance systems. These systems continuously sense the dynamic state of the vehicle and the roadway situation, and they assess the potential for a collision. When the system determines that an emergency situation might be developing, it warns the driver to take evasive action. Such countermeasure systems must be subjected to rigorous testing to ensure reasonable performance in all foreseeable circumstances and effectiveness in reducing the incidence of collisions. The efficiency and safety of testing can be greatly enhanced by using a dynamic simulation of a vehicle in near-collision situations and “equipping” the vehicle with a proposed collision avoidance system. This paper discusses the development and application of a time-domain simulation code based on a dynamic model of the driver/vehicle/counter-measure system.

Biodiesel has been used to reduce petroleum consumption and pollutant emissions. B20, a 20% blend of biodiesel with 80% petroleum diesel, has become the most common blend used in the United States. Little quantitative information is available on the impact of biodiesel on engine operating costs and durability. In this study, eight engines and fuel systems were removed from trucks that had operated on B20 or diesel, including four 1993 Ford cargo vans and four 1996 Mack tractors (two of each running on B20 and two on diesel). The engines and fuel system components were disassembled, inspected, and evaluated to compare wear characteristics after 4 years of operation and more than 600,000 miles accumulated on B20. The vehicle case history-including mileage accumulation, fuel use, and maintenance costs-was also documented. The results indicate that there was little difference that could be attributed to fuel in operational and maintenance costs between the B20- and diesel-fueled groups.

Previous studies have shown that regenerating particulate filters are very effective at reducing particulate matter emissions from diesel engines. Some particulate filters are passive devices that can be installed in place of the muffler on both new and older model diesel engines. These passive devices could potentially be used to retrofit large numbers of trucks and buses already in service, to substantially reduce particulate matter emissions. Catalyst-type particulate filters must be used with diesel fuels having low sulfur content to avoid poisoning the catalyst. A project has been launched to evaluate a truck fleet retrofitted with two types of passive particulate filter systems and operating on diesel fuel having ultra-low sulfur content. The objective of this project is to evaluate new particulate filter and fuel technology in service, using a fleet of twenty Class 8 grocery store trucks. This paper summarizes the truck fleet start-up experience.