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Particulate emission from diesel engines is one of the most important pollutants in urban areas. As a result, particulate emission control from urban bus diesel engines using particle filter technology is being evaluated at several locations in the US. A project entitled “Clean Diesel Demonstration Program” has been initiated by NY City Transit under the supervision of NY State DEC and with active participation from several industrial partners. Under this program, several NY City transit buses with DDC Series 50 engines have been equipped with continuously regenerating diesel particulate filter system and are operating with ultra low sulfur diesel (< 30 ppm S) in transit service in Manhattan since February 2000. These buses are being evaluated over a 8-9 month period for operations, maintainability and durability of the particulate filter.

In urban areas, particulate emission from diesel engines is one of the pollutants of most concern. As a result, particulate emission control from urban bus diesel engines using particle filter technology is being evaluated at several locations in the US. A project entitled, “Clean Diesel Vehicle Air Quality Project” has been initiated by NY City Transit under the supervision of NYSDEC and with active participation from several industry partners. Under this program, 25 NY City transit buses with DDC Series 50 engines have been equipped with continuously regenerating diesel particulate filter systems and have been operating with ultra low sulfur diesel (< 30 ppm S) in transit service in Manhattan since February 2000. These buses were evaluated over a 9 month period for operations, maintainability and durability of the particulate filter.

Since 1989, a research and development program has been ongoing to determine the viability of equipping a DDC 6V-92TA engine (the engine most commonly used in North America for transit buses) with a diesel particulate filter system. The engine is operated on a Southeastern Pennsylvania Transit Authority (SEPTA) Neoplan bus. The initial design targets included: the reduction of particulate emissions to levels below 0.1 g/bhp.hr. as well as the 1990 Clean Air Act Amendments, for carbon monoxide and hydrocarbons. a requirement for no ancillary hardware or energy sources in order to achieve regeneration. design simplicity for easy removal and inspection. good performance for normal SEPTA in-service conditions. low cost. Initially, baseline measurements were taken to determine under what conditions the filter system would have to perform. Several initial designs were evaluated with varying degrees of success.

Recently, 3000 catalytic purifiers have been sold into Santiago, Chile, for use on urban buses. The sale into Santiago resulted from over two years of demonstrating the performance of diesel catalytic purifiers in various Latin American countries. This paper highlights the results of the demonstrations including a variety of engine-types, opacity reductions provided by the use of purifiers, preliminary durability data and the present status of the use of catalytic technology in Latin America.

The New York City Metropolitan Transit Authority (MTA) has initiated a program to utilize various diesel emission control, alternative fuel, and hybrid electric drive technologies as part of its ongoing effort to provide environmentally friendly bus service. The New York State Department of Environmental Conservation (DEC) has joined with the MTA and Environment Canada in evaluating this program, and has established a protocol for measuring both regulated and unregulated emissions, as well as other operational parameters. This paper compares and contrasts the emissions of buses powered by Detroit Diesel Series 50 diesel engines and Series 50G Compressed Natural Gas (CNG) engines. All buses have been tested for regulated emissions at the Emissions Research and Measurement Division of Environment Canada, in Ottawa, Ontario. Unregulated emissions measurements, including particle size distributions and chemical analysis, have been supported by DEC staff.

A series of demonstration programs have been carried out over the last three years to determine the efficiency and performance of diesel catalytic converters on urban buses for smoke and gaseous emissions reductions. Some of these studies and results were outlined last year in an SAE Paper No. 930132. This paper highlights the final results of the demonstration programs including the gaseous emissions and opacity reductions achieved on various types of diesel powered engines by using diesel catalytic converters. Also included in this paper is durability data obtained on the converters during these demonstrations.

SAE Paper 930131 outlined initial work performed on a diesel particulate filter system using a copper additive for regeneration. Laboratory evaluations of soot oxidation, fuel stability, and emissions reductions were presented along with preliminary field data. Since then, a total of thirty-four buses have been included in the North American fleet trials. The buses are powered by different engines and engine configurations. Results of the field trial are presented along with problems encountered and their resolution.

The recent tightening of emission standards for new heavy duty engines has lead to the development and implementation of alternative fuel engines, particularly for urban transit bus applications. Alternative fuels are intended to offer a potential emissions benefit with regards to the regulated emissions, and especially the particulate matter, which has received the greatest degree of regulatory action. However, the entire composition of the engine emissions should be considered when evaluating the environmental benefits of these new fuels, and also the continued performance of these engines in actual fleet service. In this study the exhaust emissions from methanol, ethanol, and diesel - powered buses were determined during transient operation of the vehicles on a heavy duty chassis dynamometer. The tests of the alcohol fuelled buses, and a control diesel bus were conducted as the buses accumulated mileage in revenue generating service.

Heavy-duty diesel engines for transit bus applications are having to meet increasingly stringent emission standards. The new engines are significantly cleaner than they were just a few years ago. However, due to the long life of transit buses in Ontario (18 years), many buses still in service are powered by older engines which produce greater amounts of regulated exhaust emissions. The Ottawa-Carleton Regional Transit Commission (OC Transpo) has an interest in reducing emissions from older transit buses in their fleet. Eight Donaldson particulate trap systems were installed on transit buses. The purpose of the work, involving four different bus/engine combinations, was to assess the practicality and benefits of particulate traps in transit applications. This paper discusses the demonstration of diesel exhaust particulate traps in Ottawa-based transit buses.