Group: System Maintenance

How do I know whether my DPF is functioning properly or not?

If you see any black smoke or soot residue at the stack or tail pipe outlet, your DPF has failed and is allowing Diesel Particulate Matter (PM) to bypass the DPF and must be replaced. There are several other types of DPF failures that are not as easy to detect because there are no visible signs. Some other common conditions that may indicate that your DPF may not be functioning properly are frequent DPF plugging or your engine may be experiencing shorter intervals between regenerations,

What is a “runaway regeneration”?

An “uncontrolled or runaway regeneration” is a spontaneous uncontrolled thermal event where a high concentration of accumulated soot of a DPF rapidly burns off. It is often caused by high soot load accumulations followed by a period of low power or idle condition. This raises the oxygen content in the flow restricted exhaust. Exhaust gas temperatures can spike to temperatures above 20000 C (36320 F) during an uncontrolled regeneration event causing immediate and irreparable damage to the DPF.

Does a DPF make my engine consume more fuel?

An Active DPF system can increase fuel consumption over older non DPF equipped engines because they use additional fuel to stimulate higher exhaust temperatures post combustion. The fuel penalty with this type of system can be as high as 5% of fuel consumption. As well, as a DPF becomes loaded with soot/PM and ash, exhaust flow is restricted reducing engine power and performance and increasing fuel consumption.

Can I shut off my engine during a regeneration?

Under normal circumstances an engine can be shut off during a regeneration without any harm to the DPF. Once the engine is shut down, the conditions that support regeneration will subside and regeneration will cease. However, caution must be exercised when parking a DPF equipped vehicle to ensure that the exhaust outlet is not exposed to any combustible substances or materials that could be damaged or catch fire by exposure to excessively high temperatures such as shop ceilings, trees and grass etc.

My engine is consuming oil. Can this harm my DPF?

Yes. Consuming engine oil with a DPF equipped engine will poison or cause irreparable damage the catalyst coating on the DPF substrate material. The trace elements that are by-products of excessive amounts of combusted engine oil attach to the catalyst coating creating a “mask” preventing the oxidation process from taking place reducing efficient regeneration regardless of exhaust temperatures. Once a DPF has been poisoned, it must be replaced. A DPF with a high concentration of oil saturated PM is highly susceptible to an Runaway Regeneration.

My DPF does it’s own regeneration, does it still need to be cleaned?

Yes. The regeneration process leaves residual sulphated ash as a by-product of combusted engine oil. The main purpose for performing a basic pneumatic cleaning is to purge the residual ash from the cells of the DPF. In addition, the efficiency of a vehicles’ regeneration is dependent upon its duty cycle. Most vehicles operating conditions don’t promote perfect regeneration that would ensure that a DPF is completely purged of unburned PM (particulate matter) therefore must be cleaned periodically.

How often does a DPF need to be cleaned?

When and how often a DPF needs to be serviced depends on several variables. Engine RPM, duty cycle, idle time, fuel quality, engine oil quality and maintenance procedures can all have a tremendous influence on how frequently a DPF needs to be serviced. The most common methods for triggering a DPF service light are based upon the hours of operation, mileage or backpressure differential in the exhaust system. Always use the OEM service manual recommendations as guideline for your application. You may need more frequent cleanings based upon application and duty cycle.

How many times can a DPF be cleaned?

If cleaned properly there is no limit to the number of DPF cleanings that can be performed. The key to this statement is that the DPFs must be cleaned by properly trained emissions personnel using the appropriate cleaning methods. It’s very common for inexperienced personnel to destroy an otherwise good DPF using improper cleaning methods even when using the most sophisticated DPF cleaning equipment.

Can I clean a DPF myself?

No. The ash and soot are hazardous waste materials that must be disposed of properly according to regional environmental regulations. Cleaning your own filter with compressed air, chemicals or water puts these hazardous materials into the air, groundwater or sewer system which is illegal and could prove to be quite costly if caught. Besides that, you can’t clean a DPF without specialized equipment. If you want proof, put some on some protective gloves, smear on some soot and attempt to clean your hands.