Cummins Particulate Filter
Meeting Low Emissions With The Right Technology

Cummins QSX15, QSX11.9, QSL9 and QSB6.7 engines ranging from 174-hp to 600-hp (130-447 kW) will meet the 2011 low emissions standards with an integrated Cummins Particulate Filter exhaust aftertreatment and a cooled exhaust gas recirculation (EGR) system incorporated with the engine.

The cooled EGR system enables clean combustion with NOx reduced by 45% compared to Tier 3, while the Cummins Particulate Filter exhaust aftertreatment system reduces particulate matter by over 90% from engine exhaust.    

Particulate aftertreatment technology is new to the off-highway equipment industry – but it is not new to Cummins. Cummins introduced on-highway engines in 2007 certified to EPA standards in North America using both cooled EGR and the Cummins Particulate Filter. Our experience of using EGR extends back to 2002.

Cummins designs and manufactures the Cummins Particulate Filter as an integrated system with the engine. Meeting Tier 4 Interim and Stage IIIB demands new levels of system integration in order to achieve very low emissions while improving performance.

Cummins capability with this technology is unmatched in the industry, reflected in these production figures at the start of 2011: EGR engines produced: over 1 million Particulate filter aftertreatment systems produced: 650,000

For detailed information on operating the Cummins Particulate Filter for Tier 4, please read our Tier 4 operating tips card [pdf, opens in new window].

Cummins Particulate Filter cutaway
How does the Cummins Particulate Filter remove particulate matter (PM)?
Cummins Particulate Filter in most cases replaces the Tier 3 muffler and provides equivalent or better sound reduction.  The Cummins Particulate Filter consists of four sections: an inlet, a Diesel Oxidation Catalyst (DOC), a Diesel Particulate Filter (DPF) and an outlet.
Exhaust flows out of the engine and into the Cummins Particulate Filter. It passes through the DOC and then into the DPF where PM is collected on the walls of the DPF. The PM collected is then oxidized to remove it from the DPF. This is known as regeneration. 

When operating conditions maintain sufficient exhaust temperatures, the DPF is continually self-regenerating. This is known as passive regeneration and results in clean exhaust out of the tailpipe. On very infrequent occasions, an active self-regeneration is required to remove a build-up of PM in the DPF, due to insufficient exhaust temperatures.

What is passive regeneration?
Cummins engines are designed to maximize the use of passive self-regeneration. This occurs when operating conditions maintain sufficient exhaust temperature, therefore enabling continuous oxidation of the PM. Passive self-regeneration is completely transparent to the operator and does not affect the machine’s operation or performance. Cummins field test results have shown that most off-highway equipment operates at a high enough engine load factor for the Cummins Particulate Filter to self-regenerate in passive mode the majority of the time.

What is active regeneration?
Active self-regeneration occurs when there is not sufficient heat in the exhaust to convert the PM being collected in the DPF. Exhaust temperatures are raised by injecting a small amount of fuel upstream of the Cummins Particulate Filter. The resulting chemical reaction over the DOC raises exhaust gas temperatures high enough to oxidize the PM from the filter. This is all done without any operator intervention.  Cummins Tier 4 Interim system is designed to minimize the need for active self-regeneration. The overall fuel consumption increase due to active regeneration of the particulate filter is barely measurable – approximately 0.1% for most applications.  This minor increase resulting from active regeneration is included within Cummins overall Tier 4 fuel efficiency improvement of up to 5%.  Cummins field tests have proven the majority of active regenerations will be less than 1% of the total operating time.

What is a stationary regeneration?
Stationary, or parked, regeneration is the same as active regeneration but takes place while the equipment is not being operated. It offers the equipment operator the option, if needed, of performing regeneration outside the normal duty cycle. Using this option may only be required in a very limited number of applications. 

Does the Cummins Particulate Filter get hotter than a typical muffler during active regeneration?
Active self-regeneration takes place typically less than 1% of equipment operating time. The skin temperature of the Cummins Particulate Filter, which is double-thermally insulated, is actually lower than the muffler skin temperature of today’s Tier 3 powered machines.

Service Intervals

What service does the Cummins Particulate Filter require?
The Cummins Particulate Filter is service-free up to 5,000 hours when low ash oil is used and the base engine is properly maintained. At that point, ash cleaning is required. The EPA has set minimum ash cleaning intervals of 4,500 hours for engines above 173 hp (129 kW). Cummins expects to reach 5,000 hours before ash cleaning is required.

What causes ash in the Particulate Filter?
Ash is incombustible material derived from the additive pack in the lube oil. All engines consume a small amount of oil as part of their normal operation. The oil is burned in the combustion chamber along with the fuel, and the resulting small amount of residual ash from the oil is trapped in the filter section of the aftertreatment system. During filter regeneration, the PM is oxidized and removed from the filter. However, ash from the lube oil cannot be oxidized and remains in the filter. 

How is the Cummins Particulate Filter serviced?
The Cummins Particulate Filter must be removed and cleaned by a Cummins-approved cleaning method and authorized technician. The ash cleaning process typically takes 30 minutes, plus the time to remove the Cummins Particulate Filter from the equipment.

What is the life of the Cummins Particulate Filter?
The Cummins Particulate Filter is designed to last the life of the engine. The aftertreatment is specially strengthened against high levels of vibration and shock loading.