The tough diesel engines used in automobiles and trucks can reach hundreds of thousands of kilometres when properly maintained. The old formulations of diesel fuel, however, are high in sulphur and fail to completely combust, producing soot that adds to air pollution. Since the development of diesel particulate filters and the introduction of low sulphur fuel, the combination has significantly reduced diesel vehicle's emissions. When a diesel owner seeks a new diesel particulate filter, he or she should follow the manufacturer's recommendations for the vehicle to avoid damaging the emissions system.
Types of diesel particulate filters
Installed in place of a muffler, a diesel particulate filter draws the diesel exhaust through a filter designed to remove the carbon, or soot, particles. Several types of diesel particulate filters used in automobiles and trucks are reusable when maintained regularly. Partial filters used in retrofitting older vehicles are not as efficient, but do remove between 50 and 85 per cent of particles from the exhaust.
Cordierite is a ceramic material used in diesel particulate filters and catalytic converter cores. The gases flow through the holes in the ceramic filter, capturing the soot on an inlet face. They are efficient and relatively economical, but have a low melting point of 1,200 degrees Celsius.
With a 2,700-degree Celsius melting point, silicon carbide is a sturdy option when manufacturing diesel particulate filters. Silicon carbide filters also force the hot gases through the filter, collecting the particles on an inlet face. However, silicon carbide is not as stable as cordierite. Large cores contain several smaller pieces attached by a cement product that expand as the filter gets hot.
Combining a variety of ceramic fibres allows the manufacturer to build custom filters for automotive and industrial diesel engines. Manufacturers adjust the density of the fibres to high, medium, or low porosity, depending on the application. The exhaust flows through the fibres, which capture the soot particles. Because an accumulation of soot clogs the filter, it requires regular maintenance.
Woven together into a filter, metal fibres capture the soot as it passes through the filter. One advantage of a metal filter is that an electric current passed through the fibres during the cleaning process helps burn off the accumulated soot. Generally, metal fibre filters are not interchangeable with cordierite or silicon carbide filters.
Cleaning the diesel particulate filter
Regular maintenance is necessary to keep a diesel particulate filter clean. Manufacturers use different processes to burn off the accumulated soot at approximately 600 degrees Celsius, reducing the soot particles to a few ashes.
Sensors monitor the accumulation of soot particles on the filter. When the system determines that the diesel particulate filter needs cleaning, it automatically adjusts the exhaust system to increase the exhaust's temperature, which burns off the soot and reduces it to ash. The regeneration intervals vary according to the make, model, and usage of the vehicle.
Passive regeneration systems rely on the high exhaust temperatures generated by highway driving. Automobiles driven mostly in the city or only on short drives may not generate enough heat to burn off the soot particles. A clogged filter reduces fuel economy and may require cleaning or replacement by a mechanic.
If the diesel particulate filter warning light flashes, the driver should take the car out onto the highway. Driving for 20 minutes at 60 km/h or faster may start the regeneration process and clean the filter. If the light stays on, a visit to the mechanic may resolve the problem with a filter change or ultrasonic cleaning.
When the diesel particulate filter clogs, a second warning light notifies the driver that a trip to the mechanic or dealership is necessary. At the shop, a mechanic can use the computer to run a regeneration program to burn off the accumulated soot. He can also change the oil and oil filter to ensure a clean running engine.
How to buy diesel particulate filters on eBay
Locating and purchasing a replacement diesel particulate filter is easy when you search the vast array of listings on eBay. Use the convenient search bar and perform a keyword such for "diesel particulate filter" to view a variety of results, or for specific listings include the make and model of the vehicle. A click on the search button reveals a wide range of diesel particulate filters appropriate for your vehicle. After selecting and purchasing a new filter, it is not long before your diesel is purring down the highway again.