Friday, March 05, 2010

The Cummins Diesel Engine AfterTreatment System

Cummins Diesel Engines have developed an after-treatment system that is very compact and easy to maintain. The only requirement is to have Diesel Exhaust Fluid available to add to the holding tank which is supplied by the Original Equipment Manufacturer.

Take a look at an over view of this system. Our fleet will be getting into these systems since we're running Cummins ISB and ISC Diesel Engines. Technology never stops growing, the age of smoky and sooty old exhaust pipes have come to an end.

Frequently Asked Questions - Cummins Aftertreatment System

1) What makes up the Cummins Aftertreatment System?

There are four major components: Selective Catalytic Reduction (SCR) Catalyst, Decomposition Reactor, DEF Dosing Valve, Cummins Particulate Filter.

2) What is DEF (Diesel Exhaust Fluid)?
DEF is a 32.5% strength urea water solution.

3) How much DEF will be required?
DEF consumption is expected to be approximately 2% of fuel consumption dependent on vehicle operation – duty cycle, geography, ratings, etc.

4) What size DEF tank is required on a vehicle?
The vehicle manufacturer/OEM will determine exact tank size and location on the vehicle. However, Cummins will be providing installation recommendations to the OEMs on tank size selections.

For example, in Europe, vehicle SCR tank sizes are typically 15 – 20 gallons.

5) What happens if the vehicle runs out of DEF?

Vehicles in 2010 that will use DEF will have two indicators on the dash that will alert the driver to quantity of DEF on board. One, there will be a new DEF gauge very similar to a fuel gauge today that will indicate level of DEF (i.e. full, half, quarter, etc.) Second, there will be a new DEF low level warning lamp that will illuminate when less than 10% of DEF is in the tank.

If the vehicle is operated such that one would run completely out of DEF the vehicle will not be shut down; however, power will be reduced enough to encourage the operator to refill the DEF tank. Once the tank has been refilled the engine will resume normal power levels.Mechanic Information to live by...


Anonymous said...

Great and very informative article! As always!
Please keep them coming.
You bring people like myself up to date information we might not get anywhere else.
Keep them coming ,your my only link to practcal application of todays new technical inovations.
Thanks again . Rodd

B.J.trotman said...

That is amazing John.Hope it's on the market soon. Looks though it could be quite expensive but if it helps the planet we should go for it.
Hope your keeping well your end.

John Whelan said...

Diesels are getting extremely technical and they are fussy beyond words. Moisture and bad grounds are the enemy. NOX gases are the enemy as well, don't leave home without a couple of jugs of DEF! Thanks for the comments!

Gregory Van Tighem said...

Hi John. Great information on the emission treatment system on Cummins engines. I noticed you said in your post: "The only requirement is to have Diesel Exhaust Fluid available to add to the holding tank which is supplied by the Original Equipment Manufacturer." You might also remind readers that there's also a requirement to clean the DEF fluid filter periodically. (Think of this as similar to a fuel filter). Also Cummins recommends that the DPF be cleaned on a truck engine very 200,000 miles (I believe.) Here is a link to the Cummins information page on the 2010 emissions:

Anonymous said...


Wow john, good post. the dpf system is the more efficient there to minimize emissions of the engine diesel.

Pedro Jr.

Lucas said...

I have a buddy who works withused diesel engines and he's been struggling with that whole DEF gauge thing. I think it's really cool that you have a DEF gauge.

geralmilan said...

We currently have a 2011 bluebird/cummins that requires D.E.F.This bus didnt come with a option heater.At what temp will the DEF freeze?Last February we had a winter storm come to DFW,TX and temps were at 25-28.We kept bus in temp 65degrees.We do keep our 2.5 gallons of DEF inside shop. Thanks for any advice.Geral

John Whelan said...

Geral,32.5% solution of DEF will begin to crystallize and freeze at 12 deg F (-11 deg C). At 32.5%, both
the urea and water will freeze at the same rate, ensuring that as it thaws, the fluid does not become diluted, or over concentrated.

The freezing and unthawing of DEF will not cause degradation of the