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This paper reports the emissions measurement results of the BIOBUS project1. Environment Canada's facilities at the Emissions Research and Measurement Division (ERMD) in Ottawa were used to conduct detailed emission measurements in order to compare the two engine types used by the urban transit bus operator in Montreal; Société des transports de Montréal (STM). The test engines were operated on 500 ppm sulphur diesel fuel, and biodiesel blends of 3 different origins (vegetable oil, animal fat and used cooking oil) at 2 different concentrations (5% and 20%). Tests were conducted using a 1998 and a 2000 model year, four-stroke, 250-HP, Cummins Diesel engines equipped with either a mechanical fuel injection pump or a computer-controlled electronic fuel injection system. All emissions tests were conducted with a degreened diesel oxidation catalyst in place, as is typical for the STM buses purchased from Nova Bus.

A 1.9L turbocharged direct-injection engine representing a model year 1998-2003 Volkswagen vehicle, equipped with the OEM diesel oxidation catalyst (DOC) and exhaust gas recirculation (EGR), was tested on an eddy-current engine dynamometer with a critical flow venturi-constant volume sampling system (CFV-CVS). The engine was operated over three steady-state modes: 1600 rev/min at 54 Nm; 1800 rev/min at 81 Nm; and 2000 rev/min at 98 Nm. Commercially available ultra-low sulfur diesel fuel (≺15 ppm S) was splash-blended with fatty acid methyl ester biodiesels derived from three different feedstocks: canola, soy, and tallow/waste fry oil. Test blend levels included: 0%, 2%, 5%, 20%, 50%, and 100% biodiesel for each feedstock.

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.

The need to assess the effect of exhaust gas emissions from heavy duty vehicles (buses and trucks) on emission inventories is urgent. Exhaust gas emissions measured during the fuel economy measurement test procedures that are used in different countries sometimes do not represent the in-use vehicle emissions. Since both local and imported vehicles are running on the roads, it is thought that studying the testing cycles of the major vehicle manufacturer countries is worthy. Standard vehicle testing cycles on chassis dynamometer from the United States, Canada, European Community Market, and Japan1 are considered in this study. Each of the tested cycles is categorized as either actual or synthesized cycle and its representativness of the observed driving patterns is investigated. A total of fourteen parameters are chosen to characterize any given driving cycle and the cycles under investigation were compared using these parameters.

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.

This paper presents the emissions testing results of various heavy duty engines and vehicles with and without retrofitted diesel oxidation catalyst technology. 1987 Cummins L10 and 1991 DDC 6V92TA DDECII engine results over the U.S. Heavy Duty Transient Test are presented for comparison to chassis test results. The vehicles in this study include two urban buses, two school buses and three heavy duty trucks. The Central Business District, New York Bus and New York Composite urban driving cycles have been used to evaluate baseline emissions and the catalyst performance on a heavy duty chassis dynamometer. The results demonstrate that 25-45% particulate reduction is readily achievable on a wide variety of heavy duty vehicles. Significant carbon monoxide and hydrocarbon reductions were also observed.

As more stringent vehicle emission standards are introduced worldwide, there is an increased need to provide a thorough assessment of the environmental impact of alternative fuels. With the advent of CNG as a viable transportation fuel, the development of advanced computer controlled fuel delivery systems is imperative in order to ensure acceptable emission performance. At present, the majority of light and medium duty engines operating on natural gas are primarily gasoline automotive engines which have been retrofitted to allow for the use of CNG. The Mobile Sources Emissions Division of Environment Canada and the Canadian Gas Association have conducted a joint test program in order to develop a database of exhaust emissions from vehicles typically converted for operation on either gasoline or natural gas at various operating temperatures.