CleanBus

About the Test Project

Air quality is important. By using public transit, you can contribute to a cleaner environment and cleaner air by reducing the number of vehicles on our roads. A single bus can carry as many people as 40 to 50 passenger vehicles at emissions close to one-quarter the level per passenger-kilometre.

Transit buses run on diesel

There are about 580 ETS buses running weekdays in Edmonton and most use diesel fuel. Diesel engines are the workhorses of Canada’s transportation industry, but emissions from diesel-powered engines are a source of air pollutants. Transit buses are considered heavy-duty diesel-powered vehicles.

Reducing air pollutants from diesel-powered engines

Over the next five years, new diesel-powered vehicles will be required to reduce emissions by over 90%. This will dramatically reduce transportation emissions over time, but what about all the diesel vehicles that are currently in use? Diesel engines are very durable and can stay in service for a long time. Is there something we can do to reduce emissions from these vehicles? We can start by testing new technology.

Testing new technology

Two ETS buses dubbed the "CleanBuses" have been retrofitted with diesel particulate filters (DPFs) and will be monitored closely for up to one year. The filter has shown positive results in warmer climates like California. The filter is an example of "after-burn" technology and can replace existing mufflers on some heavy-duty diesel-powered vehicles.

Used in combination with ultra-low sulphur diesel fuel, the filters have reduced air pollutants by up to 80%. This includes pollutants such as:

• Soot (particulate matter)
• Carbon monoxide
• Hydrocarbons

To work most efficiently the DPF-equipped bus also needs special ultra-low sulphur diesel fuel. While most diesel fuel used in Canada is already low sulphur, effective 2006 ultra-low sulphur diesel with less than 15 parts per million of sulphur will become standard for on-road use in Canada.

The filters will be cleaned regularly of all trapped soot (particulate matter that otherwise went into the air), which is then destroyed using environmentally sound procedures.

Easy to install, the DPF is one of the most economical ways to reduce harmful emissions from heavy-duty vehicles, including transit buses.

Why test the DPF in Edmonton?

Although this new technology has shown positive results in other cities around the world, the DPF needs to be tested in our colder climate.

Environment Canada will be testing the filters and monitoring the exhaust during the winter of 2003 and 2004. The testing uses an on-board computer system that measures what comes out of the exhaust pipe.

This test project is one step towards a cleaner environment and cleaner air in Edmonton and the entire country.

Background

Diesel engines are a significant source of particulate matter (PM), nitrogen oxides (NOx), carbon monoxide (CO), and hydrocarbon (HC) emissions.

The U.S. Environmental Protection Agency and Environment Canada have identified PM10 (particulate matter equal to or less than 10 micrograms) as a health concern and declared it to be toxic under the Canadian Environmental Protection Act.

The California Air Resources Board (CARB) has sponsored a significant amount of research into the health effects of PM from diesel engine emissions.

Options to reduce particulate matter from diesel-powered vehicles:

• Substitution of diesel with cleaner burning alternative fuels, such as natural gas, biodiesel, propane, etc.
• Reduction in overall kilometres travelled by changing transportation demand.
• Technological advances in engine design and engine pollution control systems.
• Utilization of "after-burn" emissions treatment devices like the diesel particulate filter in the existing fleet.

The diesel particulate filter (DPF)

The DPF is an example of the "after-burn" mitigation strategy and is typically designed as a replacement for a vehicle’s existing muffler.

Open the Fleetguard Emissions Solutions presentation (PDF 480 KB) for details on the DPF’s function.These devices are designed to operate exclusively with ultra-low sulphur diesel fuel, which has been mandated by the federal government to be the Canadian standard by 2006.

The DPF removes exhaust pollutants via a two-stage process:

In the initial oxidation stage, carbon monoxide (CO) and hydrocarbon (HC) are converted to carbon
• dioxide (CO2) and water (H2O).
In the second stage, soot (particulate matter) is trapped on the walls of the filter and is
• subsequently destroyed.
• Over time, the filter’s capacity to hold deposited particles becomes fully utilized so the filters must be regularly cleaned, once every two to three years depending on duty cycle.
• One of the most attractive characteristics of DPF technology is that it is economical in relation to conversions to alternative fuels, as it can be applied to existing diesel engines which can have extremely long operational lives (20-30 years).

The US EPA has certified several DPF designs for use in the United States (including the Johnson Matthey CRT® diesel particulate filter).

Research shows positive results

• Laboratory dynamometer testing indicates that DPFs, when operated with ultra low sulphur diesel fuel (ULSD), can reduce PM, CO and HC emissions by as much as 80-90%
• In-use testing under a variety of environmental conditions can verify the above results.
• It is critical that the Canadian transportation industry gain greater knowledge and understanding as to the effectiveness of DPF technology under Canadian climatic conditions, most notably under severe cold temperatures, as engine exhaust temperature must be maintained at a minimum level for DPF technology to properly function. Only in-use testing under a variety of environmental conditions and uses can definitively answer the above question.

Testing the DPF in Edmonton

• Environment Canada emissions testing would be conducted twice.
• Each test would consist of an original equipment manufacturer (OEM) configuration and a DPF configuration (without DPF installed and with DPF installed).
• The first testing would be completed during the first winter of operation (2003) with the installed DPF.
• The second set of testing would be completed at a later time within a one-year window (2004)

The two sets of testing will be performed during two winter seasons (2003 and 2004) as one of the prime objectives of the project is to evaluate the winter performance of the technology.

Reporting on results

Environment Canada (Emissions Research and Measurement Division) will produce a report on the DPF’s performance. The report will include a discussion of the testing methodology, emission results, and conclusions as to the DPF’s performance and effectiveness during the demonstration period.

The Edmonton Transit System will produce a report that analyzes the impacts, if any, of the DPF on bus performance (based on their monitoring program). Project aspects to be monitored by the municipal transit authority will include fuel consumption, engine back-pressure, engine oil consumption, general engine wear and bus operation characteristics (based on driver observations/experiences).

The Clean Air Strategic Alliance vehicle emissions team will make recommendations about the use of this technology after evaluating the results using CASA’s consensus decision-making process that includes environmental non-government organizations, government, and industry.

All the results and evaluation will be posted on this website and shared with municipalities and the Canadian transportation industry.

History

The diesel particulate filter (CleanBus.ca) test project was initiated in Edmonton, Alberta to investigate the reduction of emissions from heavy-duty diesel-powered vehicles. Diesel particulate filters were installed on two Edmonton Transit buses and the reports outlines the results from two testing periods, one in January 2003 and the other in January 2004.

Environment Canada tested the buses without the filters and then again with the filters using one-of-a-kind on-board testing equipment. Testing was conducted to see if there were significant reductions in the total hydrocarbons (THC), carbon monoxide (CO), nitrogen oxides (NOx), and total particulate matter (TPM) emissions while the buses were operated with the filters.

The first round of exhaust emissions testing in January 2003 concludes that both buses showed decreases in total hydrocarbons between 51-60 per cent, carbon monoxide between 68-80 per cent, and total particulate matter between 60-73 per cent. There was a significant increase in nitrogen oxides (NOx) emissions on one bus, and no statistical difference in NOx emissions on the other bus. The variance in NOX was not explained by Environment Canada.

After a year of normal operations, the buses were tested for the second time in January 2004. The second round of testing shows decreases in total hydrocarbons between 61-87 per cent, carbon monoxide between 83-89 per cent, and total particulate matter between 73-75 per cent.

All of the reductions occurred without a change in fuel consumption levels.

Partners

PARTNERS ON BOARD

Generous financial and in-kind contributions from the following sponsors made the Diesel Particulate Filter Test Project a reality.

Thank you to our partners for supporting this great initiative:

• Alberta Environment
• Alberta Transportation
• Environment Canada
• Transport Canada’s MOST program
• Canadian Association of Petroleum Producers
• CASA
• Edmonton Transit System
• Fleetguard Emission Solutions
• Pattison Outdoor Advertising
• Shell Canada Ltd

Quick facts

Diesel Particulate Filter (DPF) Test Project

• Two ETS buses dubbed the "CleanBuses" have been retrofitted with diesel particulate filters (DPFs) and will be monitored closely for up to one year.
• The filter is an example of "after-burn" technology and can replace existing mufflers on some heavy-duty diesel-powered vehicles.
• Diesel particulate filter + ultra-low sulphur fuel = Up to 80% reductions in particulate matter (soot), carbon monoxide, and hydrocarbons.
• The filters will be cleaned regularly of all trapped soot (particulate matter) that would otherwise go into the air and destroyed using environmentally-sound procedures.
• This one-year project will evaluate if DPFs can work effectively during Canada’s winter months.
• Environment Canada will be testing the filters and monitoring the exhaust during the winter of 2003 and 2004.
• The Clean Air Strategic (CASA) is managing this project with the financial and in-kind support of several partners.
• Edmonton Transit System (ETS)
• There are about 570 ETS buses running every day in Edmonton.
• Riding public transit is an important way to reduce air pollution from motor vehicles.
• A single transit bus can carry as many people as 40 to 50 passenger vehicles at emissions close to one-quarter the level per passenger-kilometre.
• Most ETS buses are diesel-powered and are considered heavy-duty vehicles.

Technical Information

DPF PILOT TEST SUMMARY

Two diesel-powered Edmonton Transit System buses will be retrofitted with diesel particulate filter (DPF) emission reduction devices.

Emissions of particulate matter (PM), hydrocarbons (HC) and carbon monoxide (CO) will be monitored for up to a one-year period.

The Clean Air Strategic Alliance’s (CASA) vehicle emissions project team (VET) will evaluate the effectiveness of the new filter technology, as well as the feasibility of the technology for use by urban transit authorities and other diesel fleet operators in Alberta.